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Kotb, Ata Wael Galal Mohamed. "Intelligent control of tracked vehicle suspension." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/intelligent-control-of-tracked-vehicle-suspension(00b9d080-2e1b-4634-89ec-061ab5899b76).html.
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Vibrations caused by rough road excitations influence tracked vehicle dynamic performance. Good capabilities of such vehicles like high mobility, manoeuvrability and comfort are guaranteed by optimal suspension systems. The suspension systems of tracked vehicles are exposed to extreme operating conditions. This creates a conflict between ride comfort and handling that is even greater than the conflict between ride comfort and handling for general road vehicles. Tracked vehicles must be able to traverse not only rough roads but also smooth terrains. The challenges in developing an optimized suspension system for tracked vehicles include the high and changeable damping forces required for tracked vehicles crossing rough terrains. The use of active or semi-active suspension systems overcomes the limitations inherent in the conventional passive suspension. However, active suspension systems are expensive, complicated to design and have high power demand. Thus, semi-active suspension systems have emerged as a good compromise between active and passive suspension system. There is considerable current research on the applications of magnetorheological (MR) fluid dampers for semi-active suspensions of executive brand of some cars. However, there is very little research on semi-active devices for tracked vehicle suspension. In fact, currently, there is no commercially available large scale MR dampers in the market that produce the high damping force to suit such applications. In response to these requirements, this research proposes a novel semi-active tracked vehicle suspension system that uses MR dampers to improve the ride comfort and handling characteristics of tracked vehicles. It also assesses the dynamics of the new suspension with various semi-active control methods. This study is conducted in four phases. The first phase provides a numerical investigation on the dynamic performance of a seven-degrees-of-freedom (7-DOF) passive suspension model of the armour personnel carrier (APC) M113 tracked vehicle. The numerical investigation considers the influence of variation of five suspension design parameters on the vehicle dynamic performance. These parameters include number, locations of hydraulic shock absorber, damping coefficient, suspension and wheel stiffnesses. The results indicate that the optimal suspension performance is attained by using two or three dampers. The best locations for these dampers are at the extreme road wheels i.e. the first, second and last road wheel stations. Moreover, the vehicle performance is reduced when the damping coefficient is increased. Additionally, low suspension stiffness offers better vehicle ride while high wheel stiffness degrades the vehicle performance. These results identify the limitations inherent in the conventional passive suspension. For the second phase, the dynamic characteristics of the hydraulic, hydro-gas and MR dampers are experimentally measured and fitted using the Chebyshev orthogonal functions to produce the restoring force surfaces for each damper, which are compared. On one hand, the restoring force surfaces of the hydraulic and hydro-gas dampers show fixed properties at specified frequencies. On the other hand, the restoring force surfaces of the MR dampers show properties that can be controlled at the same specified frequencies by the variation of the applied current levels. Thus, the potential and the effectiveness of the controllable properties of MR dampers for semi-active vibration control is demonstrated. Also, in this phase, the best set of parameters to use in the modified Bouc-Wen model to characterise the MR dampers, has been derived. The third phase of the project is also experimentally based. A new and novel test rig which represents the 7-DOF scaled suspension model of the tracked vehicle is designed and fabricated. The primary purpose of the test rig is to evaluate the performance of the proposed suspension with MR dampers. Furthermore, experiments are conducted on the test rig to evaluate some semi-active control methods and their effectiveness in reducing suspension vibration. The results show that the use of two or three MR dampers at the extreme wheels offers optimal suspension performance. This confirms the numerical results that are derived from the full scale passive suspension system with hydraulic dampers. The experimental results also show that skyhook control and hybrid control (which combines groundhook and skyhook controls) of the semi-active suspension are more effective in reducing the road-induced vibration and improving the suspension dynamic behaviours. Also, validations of the predicted responses of the semi-active scaled MR suspension model with the measured responses have been presented. The fourth and final phase provides a numerical simulation on the development and evaluation of the semi-active control methods for a full scale tracked vehicle suspension with MR dampers using the validated suspension model. Three semi-active control strategies are proposed. The first two controllers are the skyhook and hybrid controls which provide better suspension performance. In addition, the third controller, which is an intelligent fuzzy-hybrid control system, is used to optimize the suspension performance. The results from this intelligent system are compared with the two traditional control methods (skyhook and hybrid controls) under bump, sinusoidal and random excitations. It is shown that the proposed controller can enhance simultaneously the vehicle ride and handling characteristics.
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Karlén, Anton. "RC-TMV : Remote Controlled Tracked Multipurpose Vehicle." Thesis, KTH, Mekatronik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-295799.
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This project seeks to design and construct a track-driven radio controlled vehicle and controller. The purpose is to research if radio can be effectively used to control the robot remotely, as well as research to what extent a tracked design increases the mobility when compared to a wheel-design. The prototype consists of two parts: Vehicle and controller. The vehicle is track-driven with two DC-engines connected by H-bridge. A receiver is fitted to the vehicle. The controller consists of two joysticks, a linear potentiometer as well as a transmitter. Testing was performed by driving the vehicle on different terrain.The results show that it is possible to control via RC and that the vehicle had increased mobility compared to wheeled designs. Two problems were identified: Firstly, the tracks used lacks friction, causing the vehicle to glide when attempting to climb certain objects. Secondly, due to the design of the chassis, objects contact the chassis body instead of the tracks. Causing the vehicle to stall.Detta projekt menar att designa samt konstruera ett banddrivet radiostyrt fordon och tillhörande kontroll. Syftet med detta är att forska om radiostyrning kan effektivt användas för fjärrstyrning och för att undersöka om band-drift ökar fordonets rörlighet jämfört med hjuldrivna motsvarigheter. Prototypen består av två delar; fordon och kontroll. Fordonet är band-drivet med två DC-motorer med högt drivmoment kopplade till en H-brygga. En mottagare är monterad på fordonet. Kontrollen består av två joysticks, en linjärpotentiometer samt en sändare. Testen genomfördes genom att låta fordonet köra över olika terräng. Resultaten av testerna visade att det är möjligt att fjärrstyra med RC samt att fordonet hade ökad rörlighet jämfört med hjuldrivna motsvarigheter. Två problem identifierades under testen. Banden saknar friktion och glider ibland i stället för att klättra över hinder. På grund av chassits form kolliderade ibland objekt med chassit före banden vilket stoppade fordonet.
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Johnson, Christopher Patrick. "Comparative Analysis of Lightweight Robotic Wheeled and Tracked Vehicle." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/76994.
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This study focuses on conducting a benchmarking analysis for light wheeled and tracked robotic vehicles. Vehicle mobility has long been a key aspect of research for many organizations. According to the Department of Defense vehicle mobility is defined as, "the overall capacity to move from place to place while retaining its ability to perform its primary mission"[1]. Until recently this definition has been applied exclusively to large scale wheeled and tracked vehicles. With new development lightweight ground vehicles designed for military and space exploration applications, the meaning of vehicle mobility must be revised and the tools at our disposal for evaluating mobility must also be expanded. In this context a significant gap in research is present and the main goal of this thesis is to help fill the void in knowledge regarding small robotic vehicle mobility assessment. Another important aspect of any vehicle is energy efficiency. Thus, another aim of this study is to compare the energy needs for a wheeled versus tracked robot, while performing similar tasks.
The first stage of the research is a comprehensive review of the state-of-the-art in vehicle mobility assessment. From this review, a mobility assessment criterion for light robots will be developed. The second stage will be outfitting a light robotic vehicle with a sensor suite capable of capturing relevant mobility criteria. The third stage of this study will be an experimental investigation of the mobility capability of the vehicle. Finally the fourth stage will include quantitative and qualitative evaluation of the benchmarking study.Master of Science
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Kanarat, Amnart. "Modeling and Simulation of a Multi-Unit Tracked Vehicle." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/9755.
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A multi-unit tracked vehicle such as a continuous haulage system is widely used in underground mining applications due to its high mobility and payload capacity on rugged and soft terrain. To automate such a system, a high fidelity model of a tracked vehicle is essential in designing a controller for each tracked vehicle in the system, and a system model is required to simulate its response to input commands.
This thesis presents the 2-D mathematical models of a tracked vehicle and a multi-unit tracked vehicle. All existing track-terrain interaction models are investigated and modified. By employing the modified track-terrain interaction model and applying Newton's second law of motion, the equations of motion of both single and multi-unit tracked vehicles can be derived. Computer programs for simulating the motions of these tracked vehicles on level ground have been implemented on a digital computer based on the derived system of differential equations. The fourth-order Runge-Kutta and Keun's methods are adopted to numerically integrate these differential equations.
The simulation results clearly show that the programs can accurately predict the motion of a tracked vehicle maneuvered on horizontal plane, and closely predict the response of a multi-unit tracked vehicle operated on level ground its command inputs.Master of Science
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Kirimlioglu, Serdar. "Multisensor Dead Reckoning Navigation On A Tracked Vehicle Using Kalman Filter." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614939/index.pdf.
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The aim of this thesis is to write a multisensor navigation algorithm and to design a test setup. After doing these, test the algorithm by using the test setup. In navigation, dead reckoning is a procedure to calculate the position from initial position with some measured inputs. These measurements do not include absolute position data. Using only an inertial measurement unit is an example for dead reckoning navigation. Calculating position and velocity with the inertial measurement unit is highly erroneous because, this calculation requires integration of acceleration data. Integration means accumulation of errors as time goes. For example, a constant acceleration error of 0.1 m/s^2 on 1 m/s^2 of acceleration will lead to 10% of position error in only 5 seconds. In addition to this, wrong calculation of attitude is going to blow the accumulated position errors. However, solving the navigation equations while knowing the initial position and the IMU readings is possible, the IMU is not used solely in practice. In literature, there are studies about this topic and in these studiessome other sensors aid the navigation calculations. The aiding or fusion of sensors is accomplished via Kalman filter. In this thesis, a navigation algorithm and a sensor fusion algorithm were written. The sensor fusion algorithm is based on estimation of IMU errors by use of a Kalman filter. The design of Kalman filter is possible after deriving the mathematical model of error propagation of mechanization equations. For the sensor fusion, an IMU, two incremental encoders and a digital compass were utilized. The digital compass outputs the orientation data directly (without integration). In order to find the position, encoder data is calculated in dead reckoning sense. The sensor triplet aids the IMU which calculates position data by integrations. In order to mount these four sensors, an unmanned tracked vehicle prototype was manufactured. For data acquisition, an xPC&ndash
Target system was set. After planning the test procedure, the tests were performed. In the tests, different paths for different sensor fusion algorithms were experimented. The results were recorded in a computer and a number of figures were plotted in order to analyze the results. The results illustrate the benefit of sensor fusion and how much feedback sensor fusion is better than feed forward sensor fusion.
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Wang, Kun. "Dynamic analysis of a tracked snowplowing vehicle and assessment of ride quality." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0007/MQ39481.pdf.
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Keese, William. "A Remotely Operated Multi-Tracked Vehicle for Subterranean Exploration of Gopher Tortoise Burrows." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3179.
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The gopher tortoise is a land tortoise living in the southeastern United States. It is a species in decline and is listed as threatened or endangered in six different states. The gopher (as commonly referred) digs burrows that it uses for many reasons and spends most of its time underground. Problems occur when trying to estimate a population because a gopher tortoise digs more than one burrow. This thesis demonstrates an innovative way to survey and investigate a gopher tortoise burrow hole by using a multi-tracked remotely operated vehicle. The vehicle carried two cameras (fore and aft) and was equipped with a microphone and LED illumination. It has tracks on four sides to increase its propulsion ratio. Its performance was evaluated in a sand pit where parameters such as incline could be controlled, and in an actual tortoise burrow. This research was done in conjunction with the Hillsborough County Parks and Recreation Department.
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Sebastian, Bijo. "Traversability Estimation Techniques for Improved Navigation of Tracked Mobile Robots." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/94629.
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The focus of this dissertation is to improve autonomous navigation in unstructured terrain conditions, with specific application to unmanned casualty extraction in disaster scenarios. Robotic systems are being widely employed for search and rescue applications, especially in disaster scenarios. But a majority of these are focused solely on the search aspect of the problem. This dissertation proposes a conceptual design of a Semi-Autonomous Victim Extraction Robot (SAVER) capable of safe and effective unmanned casualty extraction, thereby reducing the risk to the lives of first responders. In addition, the proposed design addresses the limitations of existing state-of-the-art rescue robots specifically in the aspect of head and neck stabilization as well as fast and safe evacuation.
One of the primary capabilities needed for effective casualty extraction is reliable navigation in unstructured terrain conditions. Autonomous navigation in unstructured terrain, particularly for systems with tracked locomotion mode involves unique challenges in path planning and trajectory tracking. The dynamics of robot-terrain interaction, along with additional factors such as slip experienced by the vehicle, slope of the terrain, and actuator limitations of the robotic system, need to be taken into consideration. To realize these capabilities, this dissertation proposes a hybrid navigation architecture that employs a physics engine to perform fast and accurate state expansion inside a graph-based planner.
Tracked skid-steer systems experience significant slip, especially while turning. This greatly affects the trajectory tracking accuracy of the robot. In order to enable efficient trajectory tracking in varying terrain conditions, this dissertation proposes the use of an active disturbance rejection controller. The proposed controller is capable of estimating and counter acting the effects of slip in real-time to improve trajectory tracking. As an extension of the above application, this dissertation also proposes the use of support vector machine architecture to perform terrain identification, solely based on the estimated slip parameters.
Combining all of the above techniques, an overall architecture is proposed to assist and inform tele-operation of tracked robotic systems in unstructured terrain conditions. All of the above proposed techniques have been validated through simulations and experiments in indoor and simple outdoor terrain conditions.Doctor of Philosophy
This dissertation explores ways to improve autonomous navigation in unstructured terrain conditions, with specific applications to unmanned casualty extraction in disaster scenarios. Search and rescue applications often put the lives of first responders at risk. Using robotic systems for human rescue in disaster scenarios can keep first responders out of danger. To enable safe robotic casualty extraction, this dissertation proposes a novel rescue robot design concept named SAVER. The proposed design concept consists of several subsystems including a declining stretcher bed, head and neck support system, and robotic arms that conceptually enable safe casualty manipulation and extraction based on high-level commands issued by a remote operator. In order to enable autonomous navigation of the proposed conceptual system in challenging outdoor terrain conditions, this dissertation proposes improvements in planning, trajectory tracking control and terrain estimation. The proposed techniques are able to take into account the dynamic effects of robot-terrain interaction including slip experienced by the vehicle, slope of the terrain and actuator limitations. The proposed techniques have been validated through simulations and experiments in indoor and simple outdoor terrain conditions. The applicability of the above techniques in improving tele-operation of rescue robotic systems in unstructured terrain is also discussed at the end of this dissertation.
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Saidane, Chiheb. "Decision support system for the management of an Army's tracked and wheeled vehicle fleet." Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion.exe/07Mar%5FSaidane.pdf.
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Thesis (M.S. in Computer Science)--Naval Postgraduate School, March 2007.Thesis Advisor(s): Man-Tak Shing, Arijit Das. "March 2007." Includes bibliographical references (p.85-86). Also available in print.
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Mezacasa, Nathan. "Metodologia para simulação dinâmica e otimização de veículos de esteira." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/179570.
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Devido as severas condições as quais veículos militares blindados de esteira são submetidos, o desenvolvimento de modelos que representam o comportamento dinâmico destes veículos torna-se imprescindível, para além da possibilidade de avaliação das intensidades das vibrações ocorrendo na cabine, ser possível criar veículos que tenham vantagens na mobilidade, fator esse que engloba tanto a transposição de obstáculos, como a rodagem em condições menos severas, e por fim, no tempo e na exatidão dos disparos, afetada pelas respostas dinâmicas que o veículo fornece. Para ser possível encontrar um veículo que desempenhe tais condições de forma satisfatória, apenas modelos que representem adequadamente as suas propriedades, apresentando respostas das acelerações e deslocamentos, não são suficientes. O objetivo deste trabalho é o desenvolvimento de um modelo numérico que tenha a capacidade de simular as condições dinâmicas extremas as quais um veículo de esteira é induzido, e também, otimizar o modelo, com a finalidade de encontrar molas e amortecedores capazes de proporcionar respostas adequadas às funções custo desenvolvidas. Estas funções objetivo são definidas como a combinação linear da aceleração e deslocamento, verticais e rotacionais, em conjunto de restrições impostas, objetivando encontrar uma combinação ideal para mobilidade, tempo e exatidão nos disparos e por fim, molas e amortecedores adequados as condições de logística Para proposta deste estudo, um modelo matemático 2D e um 3D, de um veículo de esteira, foi desenvolvido. O modelo possibilita a avaliação dos graus de liberdade de deslocamento vertical das massas não suspensas e do deslocamento vertical, arfagem e rolagem da massa suspensa. Os efeitos da esteira são modelados como molas verticais lineares exercendo uma força de restauração para alinhar as rodas de rodagem, proporcional ao deslocamento relativo entre essas rodas. A otimização é feita através de ferramentas numéricas presentes no software comercial Simulink, sendo necessário o desenvolvimento das funções custo que caracterizem os objetivos ideais para cada tipo de análise. Os resultados de simulações numéricas sob a forma de cursos de deslocamento de pontos característicos do casco e deslocamentos dos eixos de rodas em um sistema de coordenadas de referência assumido, também estão incluídos, bem como as quantidades de valor RMS de cada uma das respostas, comparando um veículo padrão, com o veículo com a suspensão otimizada.Due to the severe conditions in which armored military vehicles are submitted, the development of models that represent the dynamic behavior of these vehicles becomes essential, besides the possibility of evaluating the vibration intensities occurring in the cabin, to be possible to create vehicles that have mobility a factor that encompasses both the transposition of obstacles, and the shooting in less severe conditions, and finally, in the time and accuracy of the shots, affected by the dynamic responses that the vehicle provides. In order to be able to find a vehicle that fulfills these conditions satisfactorily, only models that adequately represent its properties, presenting responses of the accelerations and displacements, are not enough. The objective of this work is the development of a numerical model that has the ability to simulate extreme dynamic conditions such as a tracked vehicle is induced, and also to optimize the model with the purpose of finding springs and shock absorbers capable of adequate alternative answers cost functions developed. These are the goals defined as a linear combination of acceleration and displacement, vertical and rotational, together imposed constraints, aiming to find an ideal combination for mobility, time and precision in the shots and, finally, springs and dampers suitable as logistics conditions To propose this study, a 2D and 3D mathematical model of a tracked vehicle were developed. The model allows the evaluation of the degrees of freedom of vertical displacement of the non-suspended masses and the vertical displacement, pitch and roll of the suspended mass. The effects of the track are modeled as linear vertical springs exerting a restoring force to align the road wheels, proportional to the relative displacement between these wheels. The optimization is done through numerical tools present in Simulink software, and it is necessary to develop cost functions that characterize the ideal objectives for each type of analysis. The results of numerical simulations in the form of displacement courses of characteristic hull points and wheel axle displacements in an assumed reference coordinate system are also included, as well as the RMS value quantities of each of the responses, comparing a standard vehicle with the optimized suspension.
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Rose, Michael Scott. "Design of a Helicopter Deployable Ground Robotic System for Hazardous Environments." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31150.
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The use of robotics in hazardous environments is becoming more common, where autonomy can handle the dull, dirty and dangerous jobs that humans have previously supported. This thesis focuses on the design of a helicopter deployable unmanned ground vehicle for use in hazardous environments, and presents the benefits of heterogeneous unmanned vehicle teams for operation in beyond line-of-site hazardous environments.
The design of a ground robot that is capable of being flown on the undercarriage of a Yamaha RMAX unmanned air vehicle is presented. The robot is size, weight, and power limited and must be capable of traversing rough, unstructured terrain. The results of testing show that the design criteria for size, weight, and mobility are met. A path planning algorithm is developed using the A* search algorithm for the planning of optimal paths through rough terrain. The algorithm makes use of a vehicle/terrain interaction model to compute the cost of path traversal. In the CONOPS, the terrain model is generated real-time during a mission through the use of a stereovision system carried on the helicopter, which station-keeps above the ground robot. The algorithm simulates the robot on the terrain and presents the best feasible path to the operator to aid in teleoperated robot navigation. Simulations of the planning algorithm provided feasible paths over a rough terrain environment.
A user study was conducted that evaluates the abilities of both mono- and stereo-vision systems in providing the teleoperator with adequate situational awareness with the intent of proving that stereovision data is more effective at aiding the user in making timely navigation decisions. The results of the study showed that the helicopter-mounted stereovision system was more efficient than the monovision system with respect to navigation time, the number of invalid moves, and total moves required for navigation of a simulated rough terrain environment.
Master of Science
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Hallbeck, Viktor. "System modelling and evaluation of main battle tank fire precision." Thesis, KTH, Fordonsdynamik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-302278.
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This master thesis describes a study of the main battle tank dynamics in order to investigate the fire precision when a tank is driving in terrain. A model has been developed to simulate the dynamic interaction between the tank's hull and the ground irregularity in MATLAB and SIMULINK through the modelling of the tank's dynamics. Two different models of suspension system have been analysed. One linear model and one hydro-pneumatic model. Further the contribution from the cannon's recoil has been modelled to investigate its contribution to the dynamics of the vehicle. The models developed are on system level and is to be implemented in a larger model. Therefore are the models simplified and the thesis investigates to what degree of simplification the models will accurately predict the movement of the tank.Denna examensarbete beskriver en studie på stridsvagnsdynamik för att undersöka precision av målträff när stridsvagnen framförs i terräng. En modell har utvecklats för att simulera hur stridsvagnar påverkas av underlagets variation i MATLAB och SIMULINK genom att modellera stridsvagnens dynamik. Två olika former av stötdämpare har undersökts, en linjär modell samt en hydro-pneumatisk modell. Även bidraget från kanonen's avfyrning har modellerats för att se hur rekylens bidrag påverkar rörelsen av stridsvagnen. Målet med studien var att ta fram en så förenklad modell som möjligt. Flera modeller har därför utvecklats för att jämföra förenklingsgraden.
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Gower, Daniel W. "Speech intelligibility in tracked vehicle and pink noise under active noise reduction and passive attenuation communications headsets /." This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-06062008-170444/.
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Pawlowski, Daniel F. "Tracking Dynamic Obstacles in a Structured Urban Environment and Subsequent Decision Making for an Autonomous Ground Vehicle." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1213804587.
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Gothing, Grant Edward. "Development of the "Discretized Dynamic Expanding Zones with Memory" Autonomous Mobility Algorithm for the Nemesis Tracked Vehicle Platform." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/34404.
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The Nemesis tracked vehicle platform is a differentially driven Humanitarian Demining tractor developed by Applied Research Associates, Inc. The vehicle is capable of teleoperational control and is outfitted with a sensor suite used for detecting and neutralizing landmines. Because the detection process requires the vehicle to travel at speeds less than 0.5 km/h, teleoperation is a tedious process. The added autonomous capabilities of waypoint navigation and obstacle avoidance could greatly reduce operator fatigue.
ARA chose to leverage Virginia Tech's experience in developing an autonomous mobility capability for the Nemesis platform. The resulting algorithms utilize the waypoint navigation techniques of Virginia Tech's JAUS (Joint Architecture for Unmanned Systems) toolkit, and a modified version of the Dynamic Expanding Zones (DEZ) algorithm developed for the 2005 DARPA Grand Challenge. The modified approach discretizes the perception zones of the DEZ algorithm and provides the added capability of obstacle memory, resulting in the Discretized Dynamic Expanding Zones with Memory (DDEZm) algorithm. These additions are necessary for efficient autonomous control of the differentially driven Nemesis vehicle.
The DDEZm algorithm was coded in LabVIEW and used to autonomously navigate the Nemesis vehicle through a waypoint course while avoiding obstacles. The Joint Architecture for Unmanned Systems (JAUS) was used as the communication standard to facilitate the interoperability between the software developed at Virginia Tech and the existing Nemesis software developed by ARA. In addition to development and deployment, the algorithm has been fully documented for embedded coding by a software engineer. With embedded implementation on the vehicle, this algorithm will help to increase the efficiency of the landmine detection process, ultimately saving lives.
Master of Science
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Pattumma, Klairoong. "VEGETATION STRUCTURE, LIGHT AVAILABILITY, AND SEDIMENT DEPOSITION WITHIN SINKHOLE BUFFERS ASSOCIATED WITH TRACKED AND WHEELED VEHICLE TRAINING AT FORT KNOX, KENTUCKY." OpenSIUC, 2011. https://opensiuc.lib.siu.edu/theses/691.
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Heavy wheeled and tracked vehicle training has been conducted on portions of the landscape of Fort Knox, Kentucky for approximately 60 years. Fort Knox is located on the Kentucky Karst Plain and sinkholes are dominant features of this area. Sinkholes and karst terrain present an atypical problem in combination with this unique land use, potentially impacting downstream and local terrestrial environment. A study of the training area sinkhole complex was conducted as a first step toward mitigating the impact of military activities and reduces potential problems of sedimentation and water quality degradation. A total of 20 sinkholes within Training Areas 9 and 10 at the Fort Knox Military Reservation were randomly selected to represent the study area. The objective of this study was to determine the relationship between stand structural characteristics, understory light availability and understory vegetation in sinkhole riparian buffers and concentrated flow paths and with the amount of sediment entering sinkholes in the study area. Vegetation data were collected during the growing months of May and June in 2009. All regressions analyses for vegetative structures have r2 values between 0.000 to 0.308 indicating weak to no correlation among the variables. Light availability and percent herbaceous cover showed moderate and weak relationship in buffers (r = 0.547, p = 0.003) and flow paths (r = 0.164, p = 0.245). Sediment gained in splay areas showed no significant relationship to vegetation structure (r = 0.039 to -0.335). The relationship between sediment gained and mean percent herbaceous cover was not significant in flow paths (r = -0.172, p = 0.2341) or buffers (r = 0.130, p = 0.292). While the results of this study suggest the amount of the sediment depositing in the sinkholes was unrelated to observe variation in sinkhole vegetation, the relationship between overstory vegetation and understory vegetation within sinkholes was more noticeable. On site observations strongly suggest that concentrated flow paths were the primary conduits for sedimentation into splay areas. Therefore, management considerations pertaining to training areas should minimize flow paths leading to sinkholes. Best management practices for Fort Knox training areas should integrate these research findings, in addition to current knowledge of riparian buffers and training areas' management requirements.
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Andersson, Tobias. "Elhybridteknik i bandvagnssystemet : Den militära nyttan i logistikfunktionen." Thesis, Försvarshögskolan, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:fhs:diva-4709.
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Fossila bränslen är ändliga resurser och FMV menar i sin Tekniska Prognos 2013 att Försvarsmakten redan nu bör planera för en omställning till alternativa tekniker till dagens förbränningsmotor. Den teknik som verkar mest lämplig som interimslösning mellan framtidens vision om ren eldrift och förbränningsmotorn är elhybridteknik. Uppsatsen undersöker hur Försvarsmaktens logistikfunktion påverkas om bandvagnssystemet skulle övergå till seriehybridteknik. Uppsatsens ansats är kvalitativ med en kombination av textstudier, intervjuer samt ett frågeformulär som besvaras av totalt tre personer fördelat på Amf1, FMTS och I19 där samtliga innehar mångårig erfarenhet av bandvagnssystemet. Formulären kompletteras med intervjuer med dessa personer samt personer på BAE Systems som bidrar med teknisk expertis. Slutsatsen är att seriehybridtekniken har potential att både direkt och indirekt påverka logistikfunktionen positivt, men att konkreta vinster är svåra att bedöma med hänsyn till osäkerheter kopplat både mot tekniska faktorer och att tekniken inte är prövad i strid.Fossil fuels are finite resources and in a report from 2013, the Swedish Defence Material Administration encourages the Swedish Armed Forces to start planning for the transition to alternative propulsion systems to reduce its dependency of fossil fuels. The most promising technology to bridge the gap between pure electric propulsion and today’s internal combustion engine is hybrid electric technology. This essay examines the implications a series hybrid solution would have on military logistics. The method used includes analysis of both scientific reports and of survey answers from personnel in the SAF with several years of experience working with the tracked vehicle Bandvagn 309. The analysis of the survey answers is completed with interviews with these people and others working at BAE Systems who contributes with technical expertise. The essay will conclude that a series hybrid solution would have a positive impact on military logistics even though it is hard to specify how great the effect would be due to technical uncertainties and the fact that the technology is yet to be tested in combat.
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Eriksson, Linus. "Motorbyte BV206 : Utredning och rekommendation." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-59659.
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Scandinavian Terrain Vehicles AB (STV) konstruerar och bygger bandvagnar för civilt bruk. I utbudet ingår även vad STV kallar Mid Life Improvement (MLI) vilket syftar i att renovera Hägglunds BV206. En del av MLI-programmet är byte av motor och växellåda där de gamla komponenterna från sent 80-tal till tidigt 90-tal byts ut mot ny motor och växellåda. Den nya kombinationen av motor och växellåda möter militär standard och blir därför en onödigt kostsam del då många av STV:s kunder skulle vara nöjda även med ett enklare alternativ. För att minska kostnaden för MLI-programmet och därmed potentiellt utöka kundkretsen undersöktes möjligheterna till att hitta nya leverantörer av motor och växellåda. Som alternativ undersöktes möjligheterna till drift genom diesel- eller Ottomotor samt transmission av typerna automatisk växellåda, hydrostatisk och elektrisk transmission. Sökning av komponenter utgick från att undersöka vilka komponenttillverkare som används av liknande applikationer. Genom en kriterieviktsmetod blev det rekommenderade lösningsalternativet motorn Cummins ISF 2.8 120 kW och växellådan Allison 1000SP. Kombinationen levererar som mest 1384 Nm och vid 5200 rpm 185 Nm till fördelningsväxeln. Resultatet styrks av att motorn enligt tillverkaren är lämpad för fordon såsom mindre lastbilar och terrängfordon samt att växellådor av samma tillverkare används till bland annat BAE Systems Hägglunds bandvagn BvS10.Scandinavian Terrain Vehicles AB (STV) is a company that designs and builds tracked vehicles for civilian usage. One of their services is what they call Mid Life Improvement (MLI) which serves to recondition Hägglunds BV206’s. A significant part of the MLI-program is the exchange of engine and transmission where components from the late 80’s to early 90’s are replaced with new parts. The new parts consist of a combination of engine and gearbox that meets military standards and is therefore an expensive part especially since many of STV’s customers would settle with a more elementary alternative. To reduce costs within the MLI-program and potentially expand clientele STV sought to find new suppliers for engine and gearbox. Considered alternatives for replacement were Otto- and Diesel engines in coupled with a transmission in the form of either an automatic gearbox, a hydrostatic or an electric transmission. By examining which suppliers were being used by similar applications and selection through a weighted criteria method, the engine Cummins ISF 2.8 120 kW and transmission Allison 1000SP were found to be the best suited alternative. The combination delivers to the distribution gearbox a maximum torque of 1384 Nm and 185 Nm at 5200 rpm. The result is attested by the fact that the engine is according to the manufacturer suitable for applications like trucks and utility vehicles together with that the same brand of transmission is used by BAE Systems Hägglunds in their BvS10.
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Valík, Michal. "Návrh mobilního robotu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318858.
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This diploma thesis deals with design of machinware of mobile robot. The purpose of this work is to design complete technical product documentation for manufacturing of a prototype. In first theoretical part of this thesis there is an analysis of contemporary situation of mobile robots. In second practical section, there is a design of all needed mechanical parts for tracked vehicle, all needed calculations are included. Diploma thesis contains hazard analysis, complete technical product documentation with 3D model included and final price statement.
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Зыонг, Ши Хиеп. "Улучшение управляемости быстроходных гусеничных машин за счет установки электромеханических механизмов поворота." Thesis, НТУ "ХПИ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/22688.
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Диссертация на соискание научной степени кандидата технических наук по специальности 05.22.02 – автомобили и тракторы. – Национальный технический университет "Харьковский политехнический институт". – Харьков, 2016.
Диссертация посвящена решению научно-прикладной задачи разработки научно обоснованных технических решений, позволяющих для быстроходных гусеничных машин (БГМ) предыдущего поколения с двухпоточными механическими ступенчатыми механизмами передач и поворота (МПП) с минимальными затратами добиться плавного управляемого изменения радиуса поворота от свободного до фиксированного с рекуперацией энергии торможения отстающего борта. ргию торможения отстающего борта на повороте в аккумуляторных батареях. При выборе типа электромоторов для МП и способа их управления выбор был остановлен на асинхронных двигателях с частотным управлением потому, что именно они обеспечивают на данном этапе наилучшее сочетание внешней моментной характеристики, малой чувствительности к ударам и вибрациям и бюджетной стоимости. Обобщена математическая модель криволинейного движения БГМ за счет введения возможности совместного использования электрического и механического приводов в двухпоточных механических ступенчатых МПП, что позволяет анализировать динамику криволинейного движения БГМ с двухпоточной трансмиссией любой структуры.Thesis for granting the Degree of Candidate of Technical sciences in speciality 05.22.02 – Automobiles and Tractors. – National Technical University "Kharkiv Polytechnic Institute". – Kharkiv, 2016. Dissertation is devoted to solving scientific problems of development of science-based technical solutions, which allow for the old tracked vehicles with double-flow mechanical stepped mechanisms of transmission and turning with minimum costs to achieve a smooth change-managed turning radius. This change comes from free radius of the turning to a fixed with recuperation of braking energy of the lagging side. Directions and embodiments of shallow modernization of double-flow mechanical stepped mechanisms of transmission and turning, proposed and verified by dint of methods of mathematical modeling and numerical experiment was allowed to bring the old tracked vehicles to the modern requirements and standards for the controllability and mobility.
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Зионг, Ші Хіеп. "Покращення керованості швидкохідних гусеничних машин за рахунок встановлення електромеханічних механізмів повороту." Thesis, НТУ "ХПІ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/22687.
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Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.22.02 – автомобілі та трактори. – Національний технічний університет "Харківський політехнічний інститут". – Харків, 2016.
Дисертація присвячена вирішенню науково-практичної задачі розробки науково обґрунтованих технічних рішень, що дозволяють для гусеничних машин попереднього покоління з двопотоковими механічними ступінчастими механізмами передач і повороту з мінімальними витратами домогтися плавної керованої зміни радіуса повороту від вільного до фіксованого з рекуперацією енергії гальмування. Запропоновані і теоретично обґрунтовані напрями і варіанти реалізації часткової модернізації двопотокових механічних ступінчастих механізмів передач і повороту, які дають можливість наблизити гусеничні машини попереднього покоління до сучасних вимог і стандартів з керованості та рухливості.Thesis for granting the Degree of Candidate of Technical sciences in speciality 05.22.02 – Automobiles and Tractors. – National Technical University "Kharkiv Polytechnic Institute". – Kharkiv, 2016. Dissertation is devoted to solving scientific problems of development of science-based technical solutions, which allow for the old tracked vehicles with double-flow mechanical stepped mechanisms of transmission and turning with minimum costs to achieve a smooth change-managed turning radius. This change comes from free radius of the turning to a fixed with recuperation of braking energy of the lagging side. Directions and embodiments of shallow modernization of double-flow mechanical stepped mechanisms of transmission and turning, proposed and verified by dint of methods of mathematical modeling and numerical experiment was allowed to bring the old tracked vehicles to the modern requirements and standards for the controllability and mobility.
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Vogel, Alexander. "Energy Usage of Personal Rapid Transit Systems : Simulation of the SkyCab Concept." Thesis, KTH, Spårfordon, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-180037.
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Den globala situationen för person- och godstransporter visar att energianvändningen inom transportsektorn stadigt ökar och prognoser tyder på att den kommer att fördubblas till 2050. Den största ökningen förväntas ske i Asien där, Kina kommer att stå för över 12 % av den globala energianvändningen år 2050. Inom EU, Europeiska Unionen, stod personbilarna 2012 för över 81 % av passagerartransporterna räknat i antal passagerarkilometrar. Nya energieffektiva och miljövänliga transportlösningar behöver utvecklas. En lösning med spårtaxi kombinerar fördelarna med konventionella vägtransportsystem (flexibilitet, tillgänglighet och attraktivitet) och spårtransportsystem (säkerhet, kapacitet och miljövänlighet). I detta examensarbete undersöks energianvändningen för spårtaxi. Detta sker i form av en fallstudie. Spårtaxi är en automatiserad transporttjänst för direktresor utan väntetider (likt taxiservice) i ett nätverk med banor som kompletterar masstransportsystem. Fokus i studien ligger på att utvärdera fordonens energianvändning i drift. Målet är att identifiera relevanta parametrar som avgör energianvändningen samt deras bidrag till denna. Frågan om effektiv energianvändning besvaras med hjälp av en simuleringsmodell. Denna baseras på konceptet SkyCab och en bedömning av fordonets parametrar. En beräkning är utförd som utgör en referens för att sedan jämföras med 16 variationer av nyckelparametrar. Relationen till växhusgaser undersöks och utsläppen beräknas för olika elektricitetsblandningar. Ett andragradspolynom är framtaget för att beskriva fordonets gångmotstånd som inkluderar uppskattningar av vagnens rullmotstånd för små, pneumatiska däck på en raksträcka samt i doserade kurvor. Hjälpkraftens energianvändning uppskattas säsom motsvarande en liten elektrisk bil och är starkt beroende av passagerarnas komfortbehov och yttre (väder)förhållanden. Ett resultat är att rullmotståndet står för cirka 44 % av energianvändningen och hjälpkraften för 33 %. Båda är potentiella mål för effektivitetsförbättringar. Ändringar av accelerationsnivåer har liten betydelse för energianvändningen då det är en mindre del av energin som regenereras. En ökning av topphastigheten är ett effektivt sätt att minska restiden med förhållanderis liten ökning av energianvändningen. Förslag lämnas i studien hur man kan minska energianvändningen genom att förbättra fordonets och banans nyckelegenskaper.he global situation of personal and freight transport shows that the energy demand for transportation steadily increases, and prognoses indicate that the energy usage will double until 2050. The largest growth rates are expected in Asia, and China in particular will account for over 12 % of global transport energy usage in 2050. Over 81 % of passenger transport in passenger kilometre was produced by passenger cars in 2012 in the European Union, and new energy eÿcient and environmental friendly solutions have to be developed.PRT (Personal Rapid Transit) systems combine the benefits of traditional road systems (flexibility, accessibility, attractiveness) and rail systems (safety, capacity, environmental friendliness). This MSc thesis investigates a concept by SkyCab AB as a case study, which o˙ers an automated, non-stop and on-demand transportation service in a dedicated network and is supposed to fill a gap between personal cars and public transport. The focus is put on the energy usage of the vehicles in the operational phase.The objective is to identify the relevant parameters that determine the energy usage and their contributions. This request is addressed by setting up a simulation model, based on the SkyCab concept and estimations of vehicle parameters. A reference calculation and 16 variations of key parameters are conducted. The relation to greenhouse gas emissions is investigated and emissions are calculated for di˙erent electricity mixes.A second-order polynomial of running resistance for the vehicle is determined, includ-ing estimations of rolling resistance of small pneumatic tyres on straight track and in superelevated curves. The auxiliary power is estimated for the SkyCab vehicle on basis of a small electric passenger car.For the reference case the energy for rolling resistance is approx. 44 % of the energy usage, and auxiliary energy contributes by 33 %. Both o˙er potential for eÿciency im-provement. The auxiliary power is strongly dependent on the passengers’ comfort needs and the ambient conditions. Changes of acceleration rates have low impact on the energy usage, since a smaller proportion of energy is regenerated. An increase in top speed is a suÿcient measure to reduce trip time with comparably low increase in energy usage. Finally, suggestions are proposed to reduce the energy usage by improving key properties of the vehicle and guideway.
Der weltweite Energiebedarf des Personen- und Gütertransports zeigt einen kontinuier-lichen Anstieg, und der Ausblick bis 2050 zeigt eine Verdopplung des gesamten Ener-giebedarfs. Die größten Zuwachsraten werden in Asien erwartet, und insbesondere China allein wird in 2050 über 12 % des weltweiten Energiebedarfs verzeichnen. Über 81 % aller Personenkilometer in der Europäischen Union in 2012 wurden mit dem persönlichen Auto-mobil durchgeführt, und ein Bedarf für energieeÿziente und umweltfreundliche Transport-möglichkeiten wird deutlich.PRT (Personal Rapid Transit) Systeme vereinen die Vorzüge von traditionellen straßenge-bundenen Transportsystemen (Flexibilität, Zugänglichkeit, Attraktivität) und Schien-ensystemen (Sicherheit, Kapazität, Umweltfreundlichkeit). Diese MSc Thesis untersucht das Transportkonzept von SkyCab AB als Fallstudie. Es bietet einen automatisierten, un-unterbrochenen und bedarfsgesteuerten Transportdienst auf einem exklusiven Netzwerk und soll so die Lücke zwischen dem persönlichen Automobil und ö˙entlichen Transport-mitteln schließen. Der Fokus wird dabei auf den Energieverbrauch des Fahrzeugs in der operativen Phase gelegt.Die Zielsetzung besteht in der Identifizierung und Quantifizierung der relevanten Para-meter, die den Energieverbrauch bestimmen. Zu diesem Zweck wird ein Simulationsmodell konfiguriert welches auf dem Konzept von SkyCab basiert und zusätzlich Abschätzungen von Fahrzeugparametern enthält. Eine Referenzberechnung und 16 Parametervariationen werden durchgeführt. Der Bezug zur Emission von Treibhausgasen wird für verschiedene Energiemixe hergestellt.Das Polynom zweiter Ordnung für den Fahrwiderstand wird aufgestellt, wobei Abschätzun-gen bezüglich des Rollwiderstands kleiner pneumatischer Reifen auf gerader Strecke und in überhöhten Kurven berücksichtigt werden. Die Zusatzleistung für das Konzeptfahrzeug wird auf Basis eines kleinen rein elektrischen Fahrzeugs abgeschätzt.Der Energieverbrauch in der Referenzsimulation für den Rollwiderstand beträgt ca. 44 % des Gesamtenergieverbrauchs, und die Zusatzenergie beläuft sich auf ca. 33 %. Beide Anteile bieten Potential zur Optimierung, und die Zusatzenergie ist stark abhängig von den Komfortbedürfnissen der Passagiere und den Umgebungsbedingungen. Variationen der Beschleunigungs- und Bremsraten haben einen geringen Einfluss auf den Energiever-brauch, da gleichzeitig ein kleinerer Anteil regeneriert wird. Eine Zunahme der Höchst-geschwindigkeit wirkt sich durch mehr regenerierte Energie vergleichsweise gering auf den bezogenen Energieverbrauch aus, reduziert jedoch die Fahrzeit merklich. Abschließend werden Potentiale von Schlüsselparametern zur Reduktion des Energieverbrauchs des Fahrzeugs und der Fahrbahn aufgedeckt.
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Peterson, Jeremy. "Directional control of a tracked machine utilizing a dual-path hydrostatic transmission /." free to MU campus, to others for purchase, 2003. http://wwwlib.umi.com/cr/mo/fullcit?p1418057.
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Chiang, Chi-Feng. "Handling characteristics of tracked vehicles on non-deformable surfaces." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0018/MQ48517.pdf.
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Chiang, Chi-Feng Carleton University Dissertation Engineering Mechanical and Aerospace. "Handling characteristics of tracked vehicles on non-deformable surfaces." Ottawa, 1999.
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Hawari, Haitham M. "Minimising track degradation through managing vehicle/track interaction." Queensland University of Technology, 2007. http://eprints.qut.edu.au/16366/.
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The rate at which a railway track deteriorates depends on the response of the track under different static and repeated dynamic forces. These wheel/rail forces lead to imperfections in the rail surface and deviation in track geometry alignment. The wheel/rail forces are dependent upon the quality of maintenance of the characteristics of both train and track. If train components such as wheelsets and suspensions are maintained to a high standard, less dynamic forces are generated at the wheel/rail interface and less damage is caused over time. Therefore, the amount and cost of maintenance of track are reduced. However, there is little known about how the characteristics of train components affect time-dependent track degradation. Track degradation through deviation of track from its ideal position has the most effect on maintenance costs. Therefore, the present research aims to investigate this track degradation and improve understanding of the effects of train characteristics (such as train mass and speed, suspension stiffness and damping) on railway tracks. The research is conducted by looking into the relationship between wheel/rail forces and track degradation on one hand and between wheel/rail forces and train characteristics on the other hand, with the objective of assisting in managing vehicle/track interaction in order to minimise track degradation. This aim is achieved by investigating the above two relationships to attain the desired relationship between track degradation and train characteristics. The research focuses on wheel/rail vertical forces (both amplitudes and frequencies), vertical track alignment (longitudinal vertical profile), and rail head defects. The study started by collecting wheel/rail vertical forces data in addition to data on vertical track degradation under sustained traffic loads on a heavy haul railway section of track in Central Queensland. Also, five years of degradation and maintenance history data were collected on three other test sections of railway track under variety of traffic conditions and loads in Central Queensland. There were four main analyses of this data employed to probe the study. The first analysis was performed by examining the track degradation history data. The standard deviation method was used in this first analysis to acquire the rate of deterioration in terms of its relationship to track profile (roughness). The second analysis was accomplished by correlating the vertical wheel/rail forces to both vertical track profile and rail roughness using signal processing principles and a function know as coherence. The third analysis was carried out by using the computer simulation software NUCARS to obtain the link between wheel/rail forces and the deterioration of the vertical track profile. The fourth analysis was achieved by combining the results obtained from the above three analyses to acquire the rate of track deterioration in terms of its relationship to varying train characteristics. The first analysis mentioned above quantified the relationship between the level of roughness of the track and rate at which that roughness deteriorated. An important outcome of this relationship is that there is a threshold of roughness below which track deterioration is minimal. The track maintenance planners can now use that threshold for cost effective targeting of tamping activities. The correlation study between track roughness and wheel/rail forces using the coherence function found, surprisingly, that the overall deterioration of the track roughness, in the absence of frequencies of forces above 30 Hz, is due to the so-called quasi-static lower frequency oscillations of dynamic forces. This conclusion together with the relationship between vehicle characteristics and track forces, established in the analyses above, has significant implications for the design of wagon bogies and for charges track owners might levy on trains using their tracks. This research is part of a larger Rail CRC project 11/4 called 'Enhancing the Optimisation of Maintenance/Renewal' being carried out in the School of Urban Development in Queensland University of Technology.
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White, Darris L. "Statistical Characterization of Vehicle and Track Interaction Using Rail Vehicle Response and Track Geometry Measurements." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36835.
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This study evaluates the dynamic interaction between rail vehicles and the track on which they travel. The measurements were analyzed in the time and frequency domain. The effects of external parameters such as the vehicle design, subgrade stiffness, and degree of curvature were analyzed and compared for both the vehicle response and the track geometry data.
This study was conducted in close cooperation with the Transportation Technology Center, Inc. (TTCI) in Pueblo, Colorado. The track and vehicle response data was collected on the High Tonnage Loop at TTCI over a span of approximately ten years. For the purpose of this study, TTCI provided this data to the Advanced Vehicle Dynamics Laboratories (AVDL) at Virginia Tech.
The analysis of the data was first completed for the vehicle response and track geometry measurements separately. In this manner, the effects of the subgrade stiffness, the degree of curvature, and the vehicle design could be evaluated for each of the measurements. The analysis of the track and rail vehicle response was successfully completed, and the results from this analysis are presented in the following chapters.
The analysis showed that the subgrade stiffness had a significant effect on the vertical wheel loads, the track crosslevel, and the track gauge. For an increase in the degree of curvature, the variation of the crosslevel increased. The dynamic response of the vertical and lateral wheel loads showed a significant dependence on the alignment of the rails. Improvements for future studies of the interaction between the track and rail vehicles have been recommended.Master of Science
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Kasim, Salim Y. "Ride Analysis For Suspension System of off-Road Tracked Vehicles." Thesis, Cranfield University, 1991. http://dspace.lib.cranfield.ac.uk/handle/1826/4664.
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In this work. an attempt has been made to develop a programming package
for ride analysis of off-road vehicles based upon a finite-element
formulation of vehicle suspension systems. Mathematical modelling of
generalised suspension systems has been carried out with several
non-linear aspects being investigated and implemented in the programming
package. such as large deflection. non-linear characteristics of springs
and dampers. bump stops and wheel separation. Different types of soi 1
have been considered together with an appropriate modelling of vehicle
tracks. Several methods for time integration of dynamic equations have
been investigated so as to deal wi th numerical instabi 1 i ty problems
expected for off-road suspension systems which often have "stiff"
differential equations of motion. Three ride analysis criteria have also
been considered in the programming package. Several case studies have been analysed using the developed programming
package. They consist of two simple case studies with known analytical
solutions. an existing wheeled off-road vehicle with published analog
computer resul t s , and an off-road tracked vehicle wi th known
experimental results. The package has been validated and proved to be an
acceptable tool for the ride analysis of off-road vehicles. within the
approximating assumptions considered. Several measures for future
development have also been suggested.
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Bodin, Anders. "Improving the mobility performance of tracked vehicles in deep snow /." Luleå : Luleå tekniska univ, 2002. http://epubl.luth.se/1402-1544/2002/10/index.html.
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Lee, Sang Uk S. M. Massachusetts Institute of Technology. "Robust motion planning for autonomous tracked vehicles in deformable terrain." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/106779.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 90-95).
Ensuring the safety of autonomous vehicles during operation is a challenging task. Numerous factors such as process noise, sensor noise, incorrect model etc. can yield uncertainty in robot's state. Especially for tracked vehicles operating on rough terrain, vehicle slip due to vehicle terrain interaction affects the vehicle system significantly. In such cases, the motion planning of the autonomous vehicle must be performed robustly, considering the uncertain factors in advance of the real-time navigation. The primary contribution of this thesis is to present a robust optimal global planner for autonomous tracked vehicles operating in off-road terrain with uncertain slip. In order to achieve this goal, three tasks must be completed. First, the motion planner must be able to work efficiently under the non-holonomic vehicle system model. An approximate method is applied to the tracked vehicle system ensuring both optimality and efficiency. Second, the motion planner should ensure robustness. For this, a robust incremental sampling based motion planning algorithm (CC-RRT*) is combined with the LQG-MP algorithm. CC-RRT* yields the optimal and probabilistically feasible trajectory by using a chance constrained approach under the RRT* framework. LQG-MP provides the capability of considering the role of compensator in the motion planning phase and bounds the degree of uncertainty to appropriate size. Third, the effect of slip on the vehicle system must be modeled properly. This can be done in advance of operation if we have experimental data and full information about the environment. However, in case where such knowledge is not available, the online slip estimation can be performed using system identification method such as the IPEM algorithm. Simulation results shows that the resulting algorithms are efficient, optimal, and robust. The simulation was performed on a realistic scenario with several important factors that can increase the uncertainty of the vehicle. Experimental results are also provided to support the validity of the proposed algorithm. The proposed framework can be applied to other robotic systems where robustness is an important issue.
by Sang Uk Lee.
S.M.
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Tappe, Jack A. "Development of star tracker system for accurate estimation of spacecraft attitude." Thesis, Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Dec/09Dec%5FTappe.pdf.
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Thesis (M.S. in Astronautical Engineering)--Naval Postgraduate School, December 2009.Thesis Advisor(s): Kim, Jae Jim ; Agrawal, Brij N. "December 2009." Description based on title screen as viewed on January 26, 2010. Author(s) subject terms: Star tracker, Planar triangles, Angle method, Spherical triangle, Quaternion estimator, Least-squares (QUEST), TRIAD Includes bibliographical references (p. 87-88). Also available in print.
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Chaar, Nizar. "Wheelset Structural Flexibility and Track Flexibility in Vehicle-Track Dynamic Interaction." Doctoral thesis, Stockholm : Farkost och flyg, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4345.
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Hunt, Geoffrey A. "Dynamic analysis of railway vehicle/track interaction forces." Thesis, Loughborough University, 1986. https://dspace.lboro.ac.uk/2134/7492.
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Methods of predicting the dynamic forces are developed for the cases of vehicles negotiating vertical and lateral track irregularities. The bounds of validity of various models of the track are evaluated, from single degree of freedom, lumped parameter models to the case of a two layered beam on elastic foundation with a moving dynamic load. For the case of the lateral response of a vehicle negotiating a track switch, a finite element model of the track is also developed. The vehicle model developed for-the vertical case contains all the rigid body modes of a four axle vehicle for which primary and secondary suspension can be included with viscous or friction suspension damping. Solution of the vehicle/track interaction problem for these non-linear models is obtained by numerical integration, vehicle and track being connected by the non-linear wheel/rail contact stiffness. The most significant forces are shown to arise from the interaction of the unsprung mass and track resilience, with the vehicle modes also making a significant contribution, particularly in friction damped cases. For the lateral case use is made of an existing model of transient vehicle behaviour containing the wheel/rail contact non-linearities, to which track resilience is added in order to predict the track forces. The model is used to predict the forces which would be anticipated at discrete lateral irregularities such as those to be found at track switches. Once again the interaction with the track introduces modes of vibration which are significant in terms of wheel/rail forces. Comparison is made with experimental results obtained from full scale tests in the field. In one experiment the vertical track forces due to a range of vehicles negotiating a series of dipped welds in the track were measured, and in a second the lateral forces were recorded at the site of an artificially introduced lateral kink. A particular application of the results is in the prediction of the rate of deterioration of vertical and lateral geometry due to dynamic forces. This is to offer an improved understanding of the deterioration mechanism in order to influence the future design of vehicles and track to reduce maintenance costs.
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WILKENS, J. T. "Vehicle Track Sensing Based on Radio Tomographic Imaging." Universidade Federal do Espírito Santo, 2016. http://repositorio.ufes.br/handle/10/9672.
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Previous issue date: 2016-03-04O aumento da quantidade de veículos nas estradas faz com que engarrafamentos representam um problema global crescente. Monitoramento do tráfego é tarefa crucial para o melhoramento do fluxo de tráfego. O foco desta dissertação de Mestrado está na proposta e no desenvolvimento de uma metodologia para a estimativa em tempo real de ocupação e velocidade de um ou dois veículos em um único segmento de pista, trafegando à velocidades que variam entre 10 km/h e 50 km/h, usando uma rede de tomografia de rádio por imagem RTI (Radio Tomographic Imaging). RTI é uma tecnologia emergente e consiste de uma rede de sensores sem fio que produz imagens da mudançaa no campo eletromagnético de uma área monitorada usando potência do sinal recebido RSS (Received Signal Strength). Isso permite o rastreamento de objetos tais como pessoas e carros que não contêm dispositivos de transcepção. A proposta é a primeira a apresentar uma rede RTI que é dividida em várias sub-redes para alcançar uma frequência de varredura de rede suficientemente rápida para evitar a desfocagem nas imagens capturadas por veículos que andam a velocidades acima dos 50 km/h. Sugere-se nesta proposta um novo método de cálculo da matriz de peso, uma nova configuração de espaçamento de nó e um novo método de detecção de veículos. A principal contribuição deste trabalho é estimular a pesquisa sobre a possibilidade de usar redes RTI como sendo parte de um sistema de transporte inteligente em um ambiente de cidades inteligentes. Esta dissertação apresenta também um novo modelo de simulação relativamente completo para o sistema RTI proposto. Este modelo gera medições RSS baseado no protocolo IEEE 802.15.4 para a comunicação ZigBee, que são processadas utilizando técnicas RTI comumente utilizadas na literatura. O modelo permite a especificação de uma rede RTI a partir do zero, incluindo posições de nó, tamanho e geometria da rede, sendo que o processamento de medição de RSS pode utilizar qualquer técnica desenvolvida. Os resultados das simulações, obtidos pós a aplicação do sistema RTI proposto para o modelo de simulação validado, indicam que é possível detectar um ou dois carros populares simultaneamente. Usando técnicas que reduzem a variância do RSS devido aos efeitos múltiplos percursos, o desempenho da detecção de veículos apresentou acurácia entre 95% e 100%.
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Leiviskä, Albin. "Load generation on a CV90 track system using multibody dynamics." Thesis, Umeå universitet, Institutionen för fysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-187750.
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Bae, Sungkoo. "GLAS spacecraft attitude determination using CCD star tracker and 3-axis gyros /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
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Frydrýšek, Jan. "Simulační modely vozidel." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218012.
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This thesis deals with simulation vehicle models for lateral control. It surveys step by step to models of tire, truck and control. At the end are showed influences of model parameters to vehicles dynamics.
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Lönnbark, Gustav. "Characterization of Track Irregularities With respect to vehicle response." Thesis, KTH, Spårfordon, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102039.
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In this thesis a study, investigating the correlation between vehicle/track forces and track irregularities, is presented. The aim is to see if the correlation increases, using the first and second order derivatives of the track irregularities instead of the amplitude of the irregularities themselves. Data from on track tests during the DynoTRAIN measurement campaign is used as input to a MatLab program. The program processes the data with filtering and calculation of the derivatives, as well as a meter-by-meter alignment of the parameters. A linear regression analysis is done and the results are presented in scatter diagrams along with their correlation coefficients. The results are inconclusive implying that there are more parameters affecting the results than the ones analyzed, suggesting multidimensional regression analysis to be used.
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Bezin, Yann. "An Integrated Flexible Track System Modelfor Railway Vehicle Dynamics." Thesis, Manchester Metropolitan University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502435.
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This thesis describes the development and validation of a versatile and Flexible Track System Model (FTSM) and its integration into a commercial railway vehicle dynamics software tool. The work was initiated to fill a gap in current disciplines and tools used to investigate problems relating to vehicle and railway track dynamics due to a lack of correlation between Finite Element (FE) and MuItibody System (MBS) based models. The. FTSM track model was validated against results from laboratory testing and compared with existing models. It was then used to study several aspects of the deterioration of ballasted track under the dynamic loading of passing vehicles at speeds, including consideration of the non-linear nature of the track support condition such as sleeper voiding and variable sleeper support stiffness. . The research contributes to the fundamental understanding of the vehicl~-track interaction forces and particularly to the relation that exists between wheel-rail contact forces and track forces. It shows that.in order to accurately predict track degradation forces, a detailed flexible track model is essential. The major differences in terms of wheel-rail contact condition and forces obtained from the conventional simplified track models and from the FTSM are also highlighted. The presence of higher frequency modes of vibration of the flexible track proves essential for those studies involving local and sudden track events. The model was also applied to the analysis and design development of innovative track structures that seem to offer several advantages with respect to conventional ballasted tracks, most importantly a more consistent or continuous support to the rail. This characteristic is shown to be essential for minimising the interactive cycle of dynamic interaction forces and track deformation leading to track settlement and deterioration.
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Tegeder, Troy. "Development of an efficient solar powered unmanned aerial vehicle with an onboard solar tracker /." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1723.pdf.
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Tegeder, Troy Dixon. "Development of an Efficient Solar Powered Unmanned Aerial Vehicle with an Onboard Solar Tracker." BYU ScholarsArchive, 2007. https://scholarsarchive.byu.edu/etd/856.
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Methods were developed for the design of a solar powered UAV capable of tracking the sun to achieve maximum solar energy capture. A single-axis solar tracking system was designed and constructed. This system autonomously rotated an onboard solar panel to find the angle of maximum solar irradiance while the UAV was airborne. A microcontroller was programmed and implemented to control the solar tracking system. A solar panel and an efficient airframe capable of housing the solar tracking system was designed and constructed. Each of these subsystems was tested individually with either ground or flight tests. Ultimately, the final assembled system was tested. These tests were used to determine where and when a UAV with an onboard solar tracker would be advantageous over a conventional solar powered UAV with PV cells statically fixed to its wings. The final UAV had a wingspan of 3.2 meters, a length of 2.6 meters, and weighed 4.1 kilograms. Its solar panel provided a maximum power output of 37.7 watts. The predicted system performance, airframe drag, and system power requirements were validated with a battery powered flight test. The UAV's analytical model predicted the drag to be 41% lower than the actual drag found from flight testing. Full system functionality was verified with a solar powered flight test. The results and analysis of the system tests are presented in this thesis. The net energy increase from the solar tracking UAV over a conventional solar powered UAV for the duration of a day is dependent on season and geographical location. The solar tracking UAV that was developed was found to have a maximum net energy gain of 34.5% over a conventional solar powered version of the UAV. The minimum net energy gain of the solar tracking UAV was found to be 0.8%.
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Rådman, Marcus. "Implementation and testing of a path tracker for a full-scale Unmanned Ground Vehicle." Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-73079.
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This project is the implementation and testing of a path tracker for a car-sized Unmanned Ground Vehicle. The vehicle, a Toyota Land Cruiser, was provided by SSC and hadpreviously been modified for remote operation. The developed path tracker uses a "follow the carrot" algorithm and has been writtenin C using the Robot Operating Software (ROS) framework and has been integrated intothe vehicles existing ROS powered software. During the implementation, the Gazebo rigid body simulator was used to simulate a simplified vehicle. Integration with the real sensors was performed using a small-scalecar, both indoors with the aid of a Vicon motion capture system and outdoors utilizingonly sensors available to the full-size car. The small-scale tests showed promise, howeverwhen full-scale field tests were performed the results showed some problems and reasonsfor these are discussed.
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Frohling, Robert Desmond. "Deterioration of railway track due to dynamic vehicle loading and spatially varying track stiffness." Thesis, Pretoria : [s.n.], 1997. http://upetd.up.ac.za/thesis/available/etd-01122009-160350.
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Flodin, Jesper. "Investigate the track gauge widening on the Iron-ore line and suggest maintenance limits." Thesis, KTH, Spårfordon, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-280154.
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Iron ore export remains a major player in the Swedish economy to date, with 90% of all iron ore produced in Europe stemming from the relatively small northern country. A large amount of this ore is transported from the mines to harbours for world-wide freight on railways. On such railway is the SwedishIron-ore Line running from Kiruna to Riksgränsen, connecting to the Norwegian Ofoten line which continues to Narvik. The line has the highest permissible axle-load in Europe at 30 tonnes, which poses challenges in its own. Historically, damage on the high rail of curves have been problematic, butremedies introduced in the form of wear adapted rail profiles has brought light to a new issue. Lowrail spalling damage, caused by rolling contact fatigue (RCF) has been problematic on the line, as it reduces the life of the rails and increases maintenancecosts. It is believed that a major factor to this damage is the track gauge width. The current limit values for maintenance of the track gauge is set at 1450mm, a figure derived from empirical studies. It is therefore the wish of the infrastructure manager Trafikverket to investigate the effect the gaugewidth has on this RCF induced damage, in order to review current maintenance practices. By applying current state of the art in rail vehicle dynamics simulations and contact mechanics, the current maintenance limit has been investigated.The outcome of said investigation has yielded a foundation of support for the current maintenance limit, as it closely aligns with where damage is calculated to form at a significantly higher rate than at lower gauges.Malmexport utgör idag en av de största pelarna av Sveriges ekonomi och står ensamt för produktionen av 90% av all järnmalm som produceras i Europa. En stor del av denna malm transporteras från gruvorna till hamnar för vidare frakt på fartyg med hjälp utav järnvägar. En sådan järnväg är den Svenska Malmbanan som går mellan Kiruna och Riksgränsen, med direkt anslutning till norska Ofotenbanan som fortsätter till Narvik. Banan är den tyngsta i sitt slag i Europa med en största tillåten axellast på 30 ton, vilket innebär egna utmaningar. Rälskador på ytterrälen i kurvor har tidigare varit problematiska, men tidiga åtgärder i form av slitageanpassade rälprofiler har motverkat dessa, och istället skänkt uppmärksamhet åt ett annat problem. Ytsplittring på innerrälen i kurvor, orsakat av rullkontaktutmattning har varit problematiskt, då det reducerar rälens livslängd, och ökar underhållskostnaderna. En faktor som tros påverka dessa skador kraftigt är spårvidden. Den nuvarande spårviddsgränsen för banan är satt till 1450mm och är baserad på tidigare empiriska studier. Det är därför den svenska infrastrukturägaren, Trafikverkets, önskan att utreda effekten av spårvidden på rullkontaktutmattnings initierade skador. Genom att applicera den senaste kunskapen inom fordonsdynamiska simuleringar och kontaktmekanik, har den nuvarande underhållsgränsen utretts. Den nämnda utredning har resulterat i en grund som stöttar den nuvarande underhållsgränsen, då den nära överensstämmer med den plats där skadorna ökar mycket kraftigt i förhållande till smalare spårvidder.
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Thellman, Jonas. "Vehicle Dynamics Testing in Advanced DrivingSimulators Using a Single Track Model." Thesis, Linköpings universitet, Fordonssystem, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-79397.
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The purpose of this work is to investigate if simple vehicle models are realisticand useful in simulator environment. These simple models have been parametrisedby the Department of Electrical Engineering at Linköping University and havebeen validated with good results. The models have been implemented in a simulatorenvironment and a simulator study was made with 24 participants. Eachtest person drove both slalom and double lane change manoeuvres with the simplemodels and with VTI’s advanced model. The test persons were able to successfullycomplete double lane changes for higher velocities with the linear tyre modelcompared to both the non-linear tyre model and the advanced model. The wholestudy shows that aggressive driving of a simple vehicle model with non-linear tyredynamics is perceived to be quite similar to an advanced model. It is noted significantdifferences between the simple models and the advanced model when drivingunder normal circumstances, e.g. lack of motion cueing in the simple model suchas pitch and roll.
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Shih, Jou-Yi. "Models for vehicle/track/ground interaction in the time domain." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/412638/.
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Due to the demands of increasing population and environmental concerns, the high-speed train has become an important means of transportation in many countries. However, severe vibration induced by high-speed trains can occur when train speeds approach the speed of waves in the ground and track deflections can then become large. Consequently, the track and ground may no longer behave linearly. The aim of this work is to develop a three-dimensional model of vehicle/track/ground interaction in the time domain that can include the consideration of soil nonlinearity. A three-dimensional time-domain model of a coupled vehicle, track and ground has been developed in the finite element (FE) software ABAQUS. A new analysis approach has been adopted for modelling the moving vehicle without the need for a user-defined subroutine. The results from a track on a hemispherical ground model surrounded by infinite elements show good agreement with the results from a wavenumber finite element/boundary element method at lower speeds. However, significant differences are found for load speeds close to the critical speed for a homogeneous ground. This has been shown to be due to a relatively long transient in the numerical simulation that requires a considerable distance to achieve convergence to steady-state results. As a result, a very long model is required to derive the steady-state results. However, this becomes expensive because of the model geometry. Moreover, the results from the hemispherical model contain incorrect whole-body displacements due to the use of the infinite elements that make the ground model become unconstrained. Therefore, a cuboid model with a fixed boundary at the bottom is used for the further simulations to prevent these incorrect phenomena. Two different cuboid models, with or without the infinite elements at the sides, are compared. Finally, a wider cuboid model with fixed boundaries is used with appropriate Rayleigh damping which shows the best results and efficiency. A very long model, around 150~300 m, is required when the load speed is equal to the critical speed for a homogeneous soft ground. However, a shorter model is sufficient to obtain the steady-state results for a layered half-space. For a load moving close to the critical speed on a layered half-space, the track oscillates with a certain dominant frequency. An investigation is presented into the dependence of the oscillating frequency on the ground properties, taking account of the dispersive surface waves. Three different methods are used to investigate this oscillating frequency for a layered half-space ground and a parametric study is carried out. The oscillating frequency is found to vary with the speed of the moving load and tends to decrease when the load speed increases. It mainly depends on the shear wave speed of the upper soil layer and the depth of this layer. A formula is introduced to estimate this oscillating frequency in a layered half-space. Finally, soil nonlinearity is introduced in the FE model through a user-defined subroutine. The nonlinearity is specified in terms of the shear modulus reduction as a function of octahedral shear strain, based on data obtained from laboratory tests on soil samples. The model is applied to the soft soil site at Ledsgård in Sweden, from which extensive measurements are available from the late 1990s. It is shown that the use of a linear model based on the small-strain soil parameters leads to an underestimation of the track displacements when the train speed approaches the critical speed, whereas the nonlinear model gives improved agreement with the measurements. However, the results are quite sensitive to the choice of nonlinear model. In addition, an equivalent linear model is considered in which the equivalent soil modulus is derived from the laboratory curve of shear modulus reduction using an 'effective' shear strain. It is shown that the predictions are improved by using a value of 20% of the maximum strain as the effective strain rather than the value of 65% commonly used in earthquake studies.
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Gong, Cencen. "The interaction between railway vehicle dynamics and track lateral alignment." Thesis, University of Huddersfield, 2013. http://eprints.hud.ac.uk/id/eprint/19755/.
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This thesis examines the effect of vehicle dynamics on lateral deterioration of the track alignment. As rail traffic runs along a route, the forces imposed upon the track cause the ballast to settle, and hence the track geometry deteriorates. At a specified value of deterioration the track geometry needs to be restored by tamping or other methods. As the deterioration is mainly in the vertical direction, this aspect has been more widely studied and models have been developed to predict vertical track geometry deterioration. On the other hand, lateral track deterioration is not as well understood, and this thesis aims to fill the gap in this knowledge. However, the understanding of the lateral deterioration mechanisms becomes more important as speed and capacity increase. This thesis describes statistical studies of track lateral deterioration, as well as the development and validation of a vehicle-track lateral dynamic interaction model. This work is undertaken to contribute to the fundamental understanding of the mechanisms of track lateral deterioration, therefore making the effective control and reduction of the lateral deterioration achievable. The statistical analysis provides a better understanding of three aspects of track lateral irregularities, namely: the relationship between vertical and lateral irregularities, the relationship between track curvature and track lateral irregularity and the change in track lateral deterioration over time. The vertical and lateral track irregularity magnitudes are clearly correlated. The track quality in the vertical direction is generally worse than in the lateral direction, however the number of track sections with lateral quality significantly worse than the vertical is non-negligible. The lateral irregularities tend to be larger on curves. It is notable that less than ten percent of the track studied has a constant lateral deterioration due to frequent maintenance activities and bidirectional lateral dynamic forces. Unlike vertical settlement, lateral deterioration develops exponentially in both magnitude and wavelength, and the major influences are found from the irregularities with wavelength longer than 10 m. The change in track lateral irregularity with different curve radii and the lateral deterioration rate are described in separate exponential power functions due to the limitation of the available track data. The parameters for these empirical equations do not remain constant due to the change in track conditions. Current track lateral models mainly focus on lateral failures such as buckling and lateral sliding. The development of lateral track irregularities tends to be studied using representative values of net lateral forces and net L/V (Lateral/Vertical) load ratios. Unlike other track lateral deterioration models, the model developed in this thesis focuses on the development of lateral irregularities based on the dynamic interactions between the vehicles and the track system. This model makes it possible to carry out more integrations and analysis of the track lateral deterioration in a realistic dynamic simulation, using vehicle models, contact conditions, track initial irregularities, and traffic mix more close to the reality. The vehicle-track lateral dynamic interaction model was validated against track geometry data measured on the West Coast Mainline (WCML) in England. It has been found that the model gives a reasonably accurate prediction of the development of lateral track irregularities. However, it also tends to predict a short wavelength deterioration that is not seen in the actual track deterioration. Improvements to the model are suggested by either adding more factors or simplifying the model depending on specific target application. Enhancing the model by including more details, such as longitudinal forces, temperature effect, more layered track systems, uneven track bed conditions and more representative wheel-rail contact conditions etc., may help understand the reason of the additional short wavelength. A sensitivity analysis was performed in order to identify the critical factors that influence lateral track deterioration. The track damage caused by specific vehicles can be controlled by understanding different vehicle dynamics behaviour on a particular track section or route. Vehicles with simple suspension design and heavy axle loads tend to cause more lateral track damage. Within a certain speed range, there will be a critical speed that generates the largest lateral deterioration. Vehicles with different dynamic behaviours can generate a potential offset of the lateral deterioration, so it is possible to design the traffic mix to cancel out the peak deterioration. However, it may not be very practical to redesign the traffic mix due to different traffic requirements. Subsequently, actions can be taken to effectively reduce track lateral deterioration, such as optimise the suspension design, vehicle weight, the selection of an optimal operation speed, and enhance the traffic mix design. As the most important interface between vehicle and track, the wheel-rail contact condition has an extremely large influence on lateral deterioration. Wheel and rail profiles with different wear conditions can cause altered vehicle-track lateral dynamic interaction. It is found that increasingly worn wheel/rail profiles within an acceptable tolerance can effectively reduce the lateral deterioration. Lateral deterioration can also be reduced by increasing all the track stiffness values, damping values and the mass of rails and sleepers, or alternatively, by decreasing the sleeper spacing. The sleeper-ballast interface is found to play the most important role in lateral deterioration. The interfaces between the sleeper and ballast shoulder, crib and base determines the non-linear characteristic such as hysteresis and sliding features. Improving the strength of the sleeper-ballast interface can improve the elastic limits and hysteresis characteristics, hence reducing the lateral deterioration. The findings of the investigation indicate that the model provides in-depth knowledge of the mechanisms influencing lateral deterioration and provides effective solutions with consideration of vehicles, wheel-rail contact and the track system. Further work would include track data with sufficient information in order to develop a more comprehensive empirical model that describes the lateral deterioration, inclusion of more potentially influential factors such as: temperature, ground condition, traffic etc. The model can be improved by taking into account additional factors such as the influence of longitudinal forces from the wheels to the rails, different weather and temperatures, subgrade and ground conditions, etc. The reason for the high frequency noise in the deterioration prediction is not understood yet and it should be discussed in terms of more accurate vehicle simulation results and more comprehensive rail and wheel worn profiles measured on the target track and vehicles. Furthermore, the sleeper-ballast lateral characteristics are not well understood and the previous research in this area is quite limited. To improve on the present work it would be useful to carry out laboratory tests in order to capture more accurately track lateral stiffness and damping values as well as the comprehensive non-linear characteristic of track lateral residual resistance behaviour.
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Le, Good G. M. "Aerodynamic characteristics of passenger cars : comparison between wind tunnel and track derived data." Thesis, Cranfield University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260296.
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Robinson, Andreas. "Implementation and evaluation of a 3D tracker." Thesis, Linköpings universitet, Datorseende, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-111887.
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Many methods have been developed for visual tracking of generic objects. The vast majority of these assume the world is two-dimensional, either ignoring the third dimension or only dealing with it indirectly. This causes difficulties for the tracker when the target approaches or moves away from the camera, is occluded or moves out of the camera frame. Unmanned aerial vehicles (UAVs) are increasingly used in civilian applications and some of these will undoubtedly carry tracking systems in the future. As they move around, these trackers will encounter both scale changes and occlusions. To improve the tracking performance in these cases, the third dimension should be taken into account. This thesis extends the capabilities of a 2D tracker to three dimensions, with the assumption that the target moves on a ground plane. The position of the tracker camera is established by matching the video it produces to a sparse point-cloud map built with off-the-shelf structure-from-motion software. A target is tracked with a generic 2D tracker and subsequently positioned on the ground. Should the target disappear from view, its motion on the ground is predicted. In combination, these simple techniques are shown to improve the robustness of a tracking system on a moving platform under target scale changes and occlusions.
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Gely, Pierre. "High frequency vehicle-track interactionsimulation : Coupling of an advanced track model with a multi-bodysystem." Thesis, KTH, Järnvägsteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-159277.
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The forces caused by the high frequency vehicle-track interaction have a great impact on thetrack maintenance. They should be represented in vehicle-track models in order to predicttheir impact. As a result, a multi-body system (MBS) should be extended with an advancedtrack model. The MBS represents the vehicle and the wheel-rail contact with a great accuracy.The track will be modeled in two different ways: a moving track model and a continuous trackmodel which is a finite element modeling (FEM). The first one will be a lumped-mass model.The most advanced system will be the second one, which is a MBS-FEM representation andoffers a great precision to represent the high frequency dynamical properties. The system willbe used to simulate pertinent phenomena such as a wheelflats, corrugations and rail joint.Based on the literature and the measurements, the model is validated in a wider frequencyrange than the one currently used (0-20Hz). The results given by both models are close tothe literature and the measurement.