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Dissertations / Theses on the topic 'Terrain vehicle'

Author: Grafiati
Published: 4 June 2021
Last updated: 17 February 2022

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1

Becker, Carl Martin. "Profiling of rough terrain." Pretoria : [s.n.], 2008. http://upetd.up.ac.za/thesis/available/etd-11262009-171410/.

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2

Smith, Robert. "Terrain-aided navigation of an underwater vehicle." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244626.

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3

Frisk, Alexander. "Real-Time Vehicle Trails in Deformable Terrain." Thesis, Umeå universitet, Institutionen för datavetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-136485.

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One way to make racing games more realistic is to have the vehicles in the game deform the terrain and leave permanent trails when driving them. This master thesis presents algorithms and theories about generating those trails behind the vehicles in real-time applications. The proposed trail system is based on Bézier curves to represent and store the path of the trails. All the steps in the algorithm needed to create the trail and handle some of the edge cases are explained in detail. The game called Snow Moto Racing Freedom by Zordix, which is used for testing and implementing the solutions, is covered as well. The finished trail system has both been implemented as a CPU and as a GPU based version, where the two implementations have been tested to see which one is the most effective in the game used. The report is summarized with a list of extensions which can be used to further develop and enhance the trail system. It ends with a summary of the project as a whole with some advices for a similar projects.
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4

Wiberg, Viktor. "Terrain machine learning : A predictive method for estimating terrain model parameters using simulated sensors, vehicle and terrain." Thesis, Umeå universitet, Institutionen för fysik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-149815.

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Predicting terrain trafficability of deformable terrain is a difficult task with applications in e.g, forestry, agriculture, exploratory missions. The currently used techniques are neither practical, efficient, nor sufficiently accurate and inadequate for certain soil types. An online method which predicts terrain trafficability is of interest for any vehicle with purpose to reduce ground damage, improve steering and increase mobility. This thesis presents a novel approach for predicting the model parameters used in modelling a virtual terrain. The model parameters include particle stiffness, tangential friction, rolling resistance and two parameters related to particle plasticity and adhesion. Using multi-body dynamics, both vehicle and terrain can be simulated, which allows for an efficient exploration of a great variety of terrains. A vehicle with access to certain sensors can frequently gather sensor data providing information regarding vehicle-terrain interaction. The proposed method develops a statistical model which uses the sensor data in predicting the terrain model parameters. However, these parameters are specified at model particle level and do not directly explain bulk properties measurable on a real terrain. Simulations were carried out of a single tracked bogie constrained to move in one direction when traversing flat, homogeneous terrains. The statistical model with best prediction accuracy was ridge regression using polynomial features and interaction terms of second degree. The model proved capable of predicting particle stiffness, tangential friction and particle plasticity, with moderate accuracy. However, it was deduced that the current predictors and training scenarios were insufficient in estimating particle adhesion and rolling resistance. Nevertheless, this thesis indicates that it should be possible to develop a method which successfully predicts terrain model properties.
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Noréus, Olof. "Modelling of six-wheeled electric transmission terrain vehicle." Licentiate thesis, KTH, Aeronautical and Vehicle Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4291.

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In vehicles with electric transmission and independent wheel stations, it is possible to have a possibility to control propulsion, steering and suspension individually for each wheel. This makes it possible to improve mobility, performance and driving safety. The long term goal of this work is to develop a methodt hat can evaluate and improve the mobility of such vehicles in terrain. This contribution concerns how a six wheeled electric transmission vehicle should be modelled to enable evaluation of the dynamic behaviour in different type of terrain. This is made by combining modelling of vehicle, transmission and tire-terrain behaviour.

For wheeled vehicles an electric transmission with hub motors provides the ability to accurately control the torque on every wheel independently, giving a great ability to improve both mobility in terrain and vehicle behaviour on road. In this work the components of a diesel-electric powertrain for off-road vehicles are modelled and a control layout with the possibility to include functions for improved performance both while driving off- and on-road is proposed.

To handle driving on soft ground, a tire/terrain model is needed. The model should include lateral deformation in order to be able to steer. A tire/terrain model is derived based on the ideas of Wong and Reece. The terrain characteristics are chosen to be described by parameters according to the Bekker model, since this data are widely available in literature.

The developed tire/terrain model has been implemented together with a vehicle model. This terrain vehicle model is shown to be able to estimate sinkage, rolling resistance, traction force and steering characteristics, of a six wheeledterrain vehicle using electric transmission.

To conclude, models of a six-wheeled vehicle with electric transmission and tire models both for soft and rigid ground have been developed. These models form a simulation platform, which makes it possible to evaluate control strategies for the electric transmission with the purpose to improve mobility.

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6

Noréus, Olof. "Modelling of six-wheeled electric transmission terrain vehicle /." Stockholm : Kungl. tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4291.

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7

Juriga, Jacob T. "Terrain aided navigation for REMUS autonomous underwater vehicle." Thesis, Monterey, California: Naval Postgraduate School, 2014. http://hdl.handle.net/10945/42654.

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Approved for public release; distribution is unlimited
This research investigates the ability to create an undersea bathymetry map and navigate relative to the map. This is known as terrain aided navigation (TAN). In our particular case, the goal was for an autonomous underwater vehicle (AUV) to reduce positional uncertainty through the use of downward-looking swath sonar and employing TAN techniques. This is considered important for undersea operations where positioning systems such as GPS are either not available or difficult to put in place. There are several challenges associated with TAN that are presented: The image processing necessary to extract altitude data from the sonar image, the initial building of the bathymetry map, incorporating a system and measurement model that takes into consideration AUV motion and sensor uncertainty and near-optimal, real-time estimation algorithms. The thesis presents a methodology coupled with analysis on datasets collected from joint Naval Postgraduate School/National Aeronautical Space Administration experimentation conducted at the Aquarius undersea habitat near Key Largo, Florida. .
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8

Pedreira, Carabel Carlos Javier. "Terrain Mapping for Autonomous Vehicles." Thesis, KTH, Datorseende och robotik, CVAP, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-174132.

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Autonomous vehicles have become the forefront of the automotive industry nowadays, looking to have safer and more efficient transportation systems. One of the main issues for every autonomous vehicle consists in being aware of its position and the presence of obstacles along its path. The current project addresses the pose and terrain mapping problem integrating a visual odometry method and a mapping technique. An RGB-D camera, the Kinect v2 from Microsoft, was chosen as sensor for capturing information from the environment. It was connected to an Intel mini-PC for real-time processing. Both pieces of hardware were mounted on-board of a four-wheeled research concept vehicle (RCV) to test the feasibility of the current solution at outdoor locations. The Robot Operating System (ROS) was used as development environment with C++ as programming language. The visual odometry strategy consisted in a frame registration algorithm called Adaptive Iterative Closest Keypoint (AICK) based on Iterative Closest Point (ICP) using Oriented FAST and Rotated BRIEF (ORB) as image keypoint extractor. A grid-based local costmap rolling window type was implemented to have a two-dimensional representation of the obstacles close to the vehicle within a predefined area, in order to allow further path planning applications. Experiments were performed both offline and in real-time to test the system at indoors and outdoors scenarios. The results confirmed the viability of using the designed framework to keep tracking the pose of the camera and detect objects in indoor environments. However, outdoor environments evidenced the limitations of the features of the RGB-D sensor, making the current system configuration unfeasible for outdoor purposes.
Autonoma fordon har blivit spetsen för bilindustrin i dag i sökandet efter säkrare och effektivare transportsystem. En av de viktigaste sakerna för varje autonomt fordon består i att vara medveten om sin position och närvaron av hinder längs vägen. Det aktuella projektet behandlar position och riktning samt terrängkartläggningsproblemet genom att integrera en visuell distansmätnings och kartläggningsmetod. RGB-D kameran Kinect v2 från Microsoft valdes som sensor för att samla in information från omgivningen. Den var ansluten till en Intel mini PC för realtidsbehandling. Båda komponenterna monterades på ett fyrhjuligt forskningskonceptfordon (RCV) för att testa genomförbarheten av den nuvarande lösningen i utomhusmiljöer. Robotoperativsystemet (ROS) användes som utvecklingsmiljö med C++ som programmeringsspråk. Den visuella distansmätningsstrategin bestod i en bildregistrerings-algoritm som kallas Adaptive Iterative Closest Keypoint (AICK) baserat på Iterative Closest Point (ICP) med hjälp av Oriented FAST och Rotated BRIEF (ORB) som nyckelpunktsutvinning från bilder. En rutnätsbaserad lokalkostnadskarta av rullande-fönster-typ implementerades för att få en tvådimensionell representation av de hinder som befinner sig nära fordonet inom ett fördefinierat område, i syfte att möjliggöra ytterligare applikationer för körvägen. Experiment utfördes både offline och i realtid för att testa systemet i inomhus- och utomhusscenarier. Resultaten bekräftade möjligheten att använda den utvecklade metoden för att spåra position och riktning av kameran samt upptäcka föremål i inomhusmiljöer. Men utomhus visades begränsningar i RGB-D-sensorn som gör att den aktuella systemkonfigurationen är värdelös för utomhusbruk.
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9

Kawale, Sujay J. "Implication of Terrain Topology Modelling on Ground Vehicle Reliability." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31241.

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The accuracy of computer-based ground vehicle durability and ride quality simulations depends on accurate representation of road surface topology as an excitation to vehicle dynamics simulation software, since most of the excitation input to a vehicle as it traverses terrain is provided by the surface topology. It is not computationally efficient to utilise physically measured terrain topology for these simulations since extremely large data sets would be required to represent terrain of all desired types. Moreover, performing repeated simulations on the same set of measured data would not provide a random character typical of real world usage. There exist several methods of synthesising terrain data through the use of stochastic or mathematical models in order to capture such physical properties of measured terrain as roughness, bank angle and grade. In first part of this work, the autoregressive model and the Markov chain model have been applied to generate synthetic two-dimensional terrain profiles. The synthesised terrain profiles generated are expected to capture the statistical properties of the measured data. A methodology is then proposed; to assess the performance of these models of terrain in capturing the statistical properties of the measured terrain. This is done through the application of several statistical property tests to the measured and synthesized terrain profiles. The second part of this work describes the procedure that has been followed to assess the performance of these models in capturing the vehicle component fatigue-inducing characteristics of the measured terrain, by predicting suspension component fatigue life based on the loading conditions obtained from the measured terrain and the corresponding synthesized terrain. The terrain model assessment methodology presented in this work can be applied to any model of terrain, serving to identify which terrain models are suited to which type of terrain.
Master of Science
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10

Smail, Robert A. "Wisconsin all terrain vehicle owners : recreational motivations and attitudes toward regulation /." Link to full text, 2007. http://epapers.uwsp.edu/thesis/2007/Smail.pdf.

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11

Mattox, Kyle E. "Joint light tactical vehicle and mine resistant ambush protected all-terrain vehicle optimum procurement ratio." Thesis, Monterey, California. Naval Postgraduate School, 2012. http://hdl.handle.net/10945/27866.

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This thesis builds an optimization decision model that can be used to determine the optimum ratio of the two vehicles that the Army and Marine Corps can purchase to minimize costs while taking into account constraints related to each vehicles capabilities, such as required off-road capabilities and transport ease for missions supported by the services. The proposed optimization decision model is a cost minimizing non-linear programming model that also accounts for changes in the average production cost of each type of vehicle by embedding a cumulative average cost formula into the objective function of the model.
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Markgren, Jonas. "Creating a self-driving terrain vehicle in a simulated environment." Thesis, Umeå universitet, Institutionen för fysik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-173273.

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Outside of the city environment, there are many unstructured and rough environments that are challenging in vehicle navigation tasks. In these environments, vehicle vibrations caused by rough terrain can be harmful for humans. In addition, a human operator can not work around the clock. A promising solution is to use artificial intelligence to replace human operators. I test this by using the artificial intelligence technique know as reinforcement learning, with the algorithm Proximal Policy Optimization, to perform some basic locomotion tasks in a simulated environment with a simple terrain vehicle. The terrain vehicle consists of two chassis, each having two wheels attached, connected to each other with an articulation joint that can rotate to turn the vehicle. I show that a trained model can learn to operate the terrain vehicle and complete basic tasks, such as finding and following a path while avoiding obstacles. I tested robustness by evaluating performance on sloped terrains with a model trained to operate on flat ground. The results from the tests with different slopes show that, for most environments, the trained model could handle slopes up to around 7.5-10 degrees without much issue, even though it had no way of detecting the slope. This tells us that the models can perform their tasks quite well even when disturbances are introduced, as long as these disturbances doesn't require them to significantly change their behaviors.
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13

Jia, Bingrui. "Modeling of All-Terrain Vehicle in Steady-State Cornering Maneuvers." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1502596074556465.

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14

Nikyar, Erfan, and Vishal Venkatachalam. "Development of Active Safety Systems for Rollover Prevention of All-Terrain Vehicles." Thesis, KTH, Fordonsdynamik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-266105.

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The sales of all-terrain vehicles (ATVs) are increasing year by year, especially in countries like Sweden, Australia and New Zealand. With the increase in sales, a proportional rise in number of accidents involving all-terrain vehicles is also evident. Of these accidents the major cause was identified as rollover occurrence. While there are some protection devices, the lack of rollover prevention devices available is glaring. In addition to that, ATVs do not have many control units or electronic systems compared to modern-day cars. This makes it difficult to implement complicated computer technology to improve vehicle stability or act as a prevention system. In this thesis, a couple of active safety systems to prevent rollover have been proposed. Lateral Load Transfer Ratio (LLTR) is used as the primary parameter to analyse and signify rollover. First, an alarm has been proposed based on LLTR and roll angle. Two different types of alarms have been analysed, one based on real-time values and the other on predicted values. The prediction-based alarm shows better performance over the other alarm by giving the driver more time to take action. Second, to remove the flaws of the alarms and take away control from the driver, in case of impending rollover, an active braking system has been proposed. Multiple braking strategies have been simulated. The strategy where the brakes are applied on the outer wheels was found to be most effective.
Försäljningen av terrängfordon (ATV:s) ökar år för år, särskilt i länder som Sverige, Australien och Nya Zeeland. Som effekt av den ökande försäljningen kan man observera en proportionell ökning av antalet olyckor med terrängfordon. Bland dessa har huvudorsaken identifierats till vältningsolyckor. Även om det i dagsläget finns anordningar som skyddar förare av ATV:s vid tippning så råder det en tydlig brist på utrustning som förebygger själva vältningen. Dessutom har ATV:s inte många reglerenheter eller elektroniska system jämfört med moderna bilar. Detta gör det svårt att implementera komplicerad elektronisk teknologi för att förbättra stabilitet och förebygga uppkomsten av vältning. I denna avhandling har flera aktiva säkerhetssystem som förebygger vältning föreslagits. Lateral Load Transfer Ratio (LLTR) används som den primära parametern för att analysera och visa på risken av vältning. Först har ett varningssystem föreslagits i form av ett larm baserat på LLTR och krängningsvinkel. Två olika typer larm har analyserats, ett baserat på realtidsvärdena av dessa parametrar och det andra på deras predikterade värden. Larmet baserat på prediktering har visat bättre resultat gentemot realtidsalarmet genom att förse föraren med mer tid för att utföra en stabiliserande manöver. För att förbättra effektiviteten av säkerhetssystemet och befria föraren från att behöva vidta åtgärder har även ett aktivt bromssystem föreslagits där olika bromsstrategier simulerats. Av dessa vältningsförebyggande bromsstrategier har det som bromsar de yttre hjulen visat bäst resultat.
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15

Griffiths, Stephen R. "Remote Terrain Navigation for Unmanned Air Vehicles." BYU ScholarsArchive, 2006. https://scholarsarchive.byu.edu/etd/1059.

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There are many applications for which small unmanned aerial vehicles (SUAVs) are well suited, including surveillance, reconnaissance, search and rescue, convoy support, and short-range low-altitude perimeter patrol missions. As technologies for microcontrollers and small sensors have improved, so have the capabilities of SUAVs. These improvements in SUAV performance increase the possibility for hazardous missions through mountainous and urban terrain in the successful completion of many of these missions. The focus of this research was on remote terrain navigation and the issues faced when dealing with limited onboard processing and limited payload and power capabilities. Additional challenges associated with canyon and urban navigation missions included reactive path following, sensor noise, and flight test design and execution. The main challenge was for an SUAV to successfully navigate through a mountainous canyon by reactively altering its own preplanned path to avoid canyon walls and other stationary obstacles. A robust path following method for SUAVs that uses a vector field approach to track functionally curved paths is presented along with flight test results. In these results, the average tracking error for an SUAV following a variety of curved paths is 3.4~m for amplitudes ranging between 10 and 100~m and spatial periods between 125 and 500~m. Additionally, a reactive path following method is presented that allows a UAV to continually offset or bias its planned path as distance information from the left and right ranging sensors is computed. This allows the UAV to to center itself between potential hazards even with imperfect waypoint path planning. Flight results of an SUAV reactively navigating through mountainous canyons experimentally verify the feasibility of this approach. In a flight test through Goshen Canyon in central Utah, an SUAV biased its planned path by 3 to 10~m to the right as it flew to center itself through the canyon and avoid the possibility of crashing into a canyon wall.
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16

Michael, John Stuart. "Characterizing occupational instabilities induced by a four-DOF all-terrain vehicle simulator." Thesis, University of Iowa, 2017. https://ir.uiowa.edu/etd/5969.

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All-terrain vehicles (ATVs) are used widely throughout the United States both for recreational activities, such as hunting and riding, and in occupational settings, such as agriculture. In both such activities, ATVs can pose a risk of injury and death resulting from a number of factors, including operator error, operating in an altered state, and misuse. In a study by Milosavlijevic et al. (2011), a survey of agricultural workers in New Zealand displayed that roughly 60% of workers who operated an ATV experienced a loss of control event. The same study showed that nearly 50% of those occurred while riding on a steep slope. Despite these high levels of incidence, little research has been performed to understand the mechanisms that lead to loss of control or instability. In order to study loss of control and instability, a four-degree-of-freedom human-in-the-loop ATV simulator was developed and integrated with a shaking table in a real-time interaction. The simulator allowed for operators to approach conditions by their own means and to study mechanisms of each individual’s approach to traversing a terrain. Inertial measurement units were used to measure the acceleration and angular velocity of each subject at the S1, T10, C7, and head. Inertial measurement units were also mounted on the ATV and table. The ATV was instrumented with 32 force sensors to sense reaction forces applied to the machine at the feet, hands, saddle, and seat. A five-camera motion capture system was used to capture posture throughout the time series of each terrain. Data were reviewed and analyzed at a finer resolution of roughly three seconds in select subjects at moments when there were peaks in both force and acceleration. Analysis showed that a cycle of instability and stability existed as moments of sudden input accelerations caused reactions in the spine and head. Further, component accelerations were analyzed to identify the acceleration of the subject relative to the ATV. The cycle and the time from input acceleration to bracing on the ATV to regain stability serve as a baseline for the subject’s reaction to input acceleration and the time between input acceleration and regaining stability.
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Aquilio, Anthony Scott. "A Framework for Dynamic Terrain with Application in Off-road Ground Vehicle Simulations." Digital Archive @ GSU, 2006. http://digitalarchive.gsu.edu/cs_diss/11.

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The dissertation develops a framework for the visualization of dynamic terrains for use in interactive real-time 3D systems. Terrain visualization techniques may be classified as either static or dynamic. Static terrain solutions simulate rigid surface types exclusively; whereas dynamic solutions can also represent non-rigid surfaces. Systems that employ a static terrain approach lack realism due to their rigid nature. Disregarding the accurate representation of terrain surface interaction is rationalized because of the inherent difficulties associated with providing runtime dynamism. Nonetheless, dynamic terrain systems are a more correct solution because they allow the terrain database to be modified at run-time for the purpose of deforming the surface. Many established techniques in terrain visualization rely on invalid assumptions and weak computational models that hinder the use of dynamic terrain. Moreover, many existing techniques do not exploit the capabilities offered by current computer hardware. In this research, we present a component framework for terrain visualization that is useful in research, entertainment, and simulation systems. In addition, we present a novel method for deforming the terrain that can be used in real-time, interactive systems. The development of a component framework unifies disparate works under a single architecture. The high-level nature of the framework makes it flexible and adaptable for developing a variety of systems, independent of the static or dynamic nature of the solution. Currently, there are only a handful of documented deformation techniques and, in particular, none make explicit use of graphics hardware. The approach developed by this research offloads extra work to the graphics processing unit; in an effort to alleviate the overhead associated with deforming the terrain. Off-road ground vehicle simulation is used as an application domain to demonstrate the practical nature of the framework and the deformation technique. In order to realistically simulate terrain surface interactivity with the vehicle, the solution balances visual fidelity and speed. Accurately depicting terrain surface interactivity in off-road ground vehicle simulations improves visual realism; thereby, increasing the significance and worth of the application. Systems in academia, government, and commercial institutes can make use of the research findings to achieve the real-time display of interactive terrain surfaces.
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18

Mann, Marilynne Jones. ""Bad Apples," Overworked Trail Workers and Landowner Relations: Meanings of ATV Riding in Maine's Clubs." Fogler Library, University of Maine, 2008. http://www.library.umaine.edu/theses/pdf/MannMJ2008.pdf.

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19

Taheri, Shahyar. "Finite Element Modeling Of Tire-Terrain Dynamic Interaction For Full Vehicle Simulation Applications." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/76991.

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Studying the kinetic and kinematics of the rim-tire combination is very important in full vehicle simulations, as well as for the tire design process. Tire maneuvers are either quasi-static, such as steady-state rolling, or dynamic, such as traction and braking. The rolling of the tire over obstacles and potholes and, more generally, over uneven roads are other examples of dynamic events which are of importance. In the latter case, tire dynamic models are used for durability assessment of the vehicle chassis, and should be studied using high fidelity simulation models. In this study, a threedimensional finite element model (FEM) of the 16 inch TMPT Tire has been developed using the commercial software package ABAQUS. The purpose of this study is to investigate tire transient dynamic behavior for various inputs. The process of running dynamic FE tire simulations starts by statically inflating and loading the tire using an implicit method with refined mesh in the contact patch. Then, by using the "result transfer" option in ABAQUS, final state vectors are used as initial conditions for subsequent simulations. Using this sequence of loading steps helps increase the efficiency of the code. The validation of the model is performed in two stages. First, tire mode shapes and associated natural frequencies and damping values are compared with the experimental data. Second, a series of transient dynamic simulations are performed using an explicit method with a fine mesh around the circumference of the tire. Finally, the FEM model results are filtered to eliminate the numerical noise, and their correlation with the test data is investigated. Moreover, the peak values and time shifts associated with spindle forces as a function of normal load are studied. The results show that the tire dynamic response is autonomous.
Master of Science
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20

Bayar, Gokhan. "Trajectory Tracking Control Of Unmanned Ground Vehicles In Mixed Terrain." Phd thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615105/index.pdf.

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Mobile robots are commonly used to achieve tasks involving tracking a desired trajectory and following a predefined path in different types of terrains that have different surface characteristics. A mobile robot can perform the same navigation task task over different surfaces if the tracking performance and accuracy are not essential. However, if the tracking performance is the main objective, due to changing the characteristics of wheel-ground interaction, a single set of controller parameters or an equation of motion might be easily failing to guarantee a desired performance and accuracy. The interaction occurring between the wheels and ground can be integrated into the system model so that the performance of the mobile robot can be enhanced on various surfaces. This modeling approach related to wheel-ground interaction can also be incorporated into the motion controller. In this thesis study, modeling studies for a two wheeled differential drive mobile robot and a steerable four-wheeled robot vehicle are carried out. A strategy to achieve better tracking performance for a differential drive mobile robot is developed by introducing a procedure including the effects of external wheel forces
i.e, traction, rolling and lateral. A new methodology to represent the effects of lateral wheel force is proposed. An estimation procedure to estimate the parameters of external wheel forces is also introduced. Moreover, a modeling study that is related to show the effects of surface inclination on tracking performance is performed and the system model of the differential drive mobile robot is updated accordingly. In order to accomplish better trajectory tracking performance and accuracy for a steerable four-wheeled mobile robot, a modeling work that includes a desired trajectory generator and trajectory tracking controller is implemented. The slippage is defined via the slip velocities of steerable front and motorized rear wheels of the mobile robot. These slip velocities are obtained by using the proposed slippage estimation procedure. The estimated slippage information is then comprised into the system model so as to increase the performance and accuracy of the trajectory tracking tasks. All the modeling studies proposed in this study are tested by using simulations and verified on experimental platforms.
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Atac, Selcuk. "Gps Based Altitude Control Of An Unmanned Air Vehicle Using Digital Terrain Elevation Data." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607383/index.pdf.

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In this thesis, an unmanned air vehicle (UAV) is used to develop a prototype base test platform for flight testing of new control algorithms and avionics for advanced UAV system development applications. A control system that holds the UAV at a fixed altitude above the ground is designed and flight tested. Only the longitudinal motion of the UAV is considered during the controller design, hence its lateral motions are controlled manually by a remote control unit from the ground. UAV&
#8217
s altitude with respect to the mean sea level and position are obtained by an onboard global positioning system (GPS) and this information is transmitted to the ground computer via radio frequency (RF) communication modules. The altitude of the UAV above the ground is calculated by using the digital terrain elevation data (DTED). A controller is designed and its gains are tuned to maintain this flight altitude at a desired value by using the mathematical model developed to represent the longitudinal dynamics of the UAV. Input signals generated by the controller for elevator deflections are transmitted back to the UAV via RF communication modules to drive onboard servomotors to generate desired elevator deflections. All controller computations and RF communications are handled by a MATLAB®
based platform on a ground computer. UAV flight tests are carried out at two different autopilot modes
namely, mean sea level (MSL) altitude hold mode and above ground level (AGL) altitude hold mode. The developed platform worked properly during flight tests and proved to be reliable in almost every condition. Moreover, the designed controller system is demonstrated to be effective and it fulfills the requirements.
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Gough, Renee D. "Assessment of tractor and all-terrain vehicle safety programs available to youth in West Virginia." Morgantown, W. Va. : [West Virginia University Libraries], 2004. https://etd.wvu.edu/etd/controller.jsp?moduleName=documentdata&jsp%5FetdId=3351.

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Thesis (M.S.)--West Virginia University, 2004.
Title from document title page. Document formatted into pages; contains xi, 76 p. Vita. Includes abstract. Includes bibliographical references (p. 55-56).
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23

Larsson, Joel. "Gimbal stabilizer for cockpit bases of terrain vehicle or combat boat : A proof of concept." Thesis, Uppsala universitet, Signaler och System, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-355160.

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The purpose of this project was to construct a 2-axis stabilized model platform, as a proof of concept, intended to use for a cockpit base of a terrain vehicle or a combat boat. The stabilization of the platform in the roll and pitch axes is realized using a feedback control system that contains a proportional-integral-derivative (PID) controller, two DC motors driving the roll and pitch movements, and a 6-axis inertial measurement unit (IMU) measuring the roll and pitch angles. The project started with a study of various stabilized platforms and the theories behind them and a model of the system was created in SimuLink to simulate the system and design the controller. After the simulations where satisfactory a model platform of a scaled-down actual size was constructed. The platform’s frame was printed in a 3D printer. The control system for the platform has been implemented. The PID controller was implemented on the Arduino Mega 2560 development board, and it regulates the pitch and roll movements through two DC motors. The platform’s pitch and roll angles are measured by a 3-axis gyroscope in an IMU sensor (MPU-6050). The measurements are processed by a Kalman filter implemented on the Arduino board to reduce the noise. The Simulink simulation provided a functioning control system. However, the prototype of the implemented model platform does not work with god stability as expected. The reason for this result is mostly due to the unsuccessful construction of the platform frame and the bad choice of motors.
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24

Wilson, Jessica L. "CHARACTERISTICS OF ALL-TERRAIN VEHICLES AND THEIR OPERATORS ON KENTUCKY FARMS." UKnowledge, 2012. http://uknowledge.uky.edu/nursing_etds/5.

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All-terrain vehicles (ATVs) were first developed and marketed in the U.S. in the 1970s. They have soared in popularity for occupational and recreational uses since that time. In 2008, there were approximately 10.2 million all-terrain vehicles (ATVs) in use in the United States. In 2001, it was estimated that 23 million Americans rode ATVs; 69% were adults and 31% children (CPSC, 2003). Deaths and injuries from ATVs have increased over time. According to the U.S. Consumer Product Safety Commission, Kentucky led the nation for ATV deaths from 2002-2006, with increasing numbers of fatalities annually. ATV use on farms is increasing across the country because the vehicles provide an efficient and reliable replacement for horses and tractors for farm work, such as checking livestock, feeding, or fence repair. Aging farmers and farmers with physical disabilities can often increase their productivity by using ATVs for their transportation needs on the farm. ATVs also serve as an inexpensive and popular recreational vehicle used by families especially in rural areas. In 2001, there were an estimated 481 ATVs per 1,000 (CI95% ± 27) farms in the southern region of the U.S. A literature review and a descriptive cross-sectional study were conducted. The specific aims of this dissertation were to: 1. Critically analyze the state of the science on ATV-related injury risk factors and explore recreational and occupational use of ATVs on farms. 2. Describe individual characteristics and demographic factors that are associated with ATV ownership and ridership among adult farmers. 3. Describe individual characteristics and environmental factors that are associated with ATV injury on farms. 4. Test models for predicting ATV ownership, ATV ridership, and ATV injury risk factors among adult farmers.
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Garratt, Matthew Adam, and m. garratt@adfa edu au. "Biologically Inspired Vision and Control for an Autonomous Flying Vehicle." The Australian National University. Research School of Biological Sciences, 2008. http://thesis.anu.edu.au./public/adt-ANU20090116.154822.

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This thesis makes a number of new contributions to control and sensing for unmanned vehicles. I begin by developing a non-linear simulation of a small unmanned helicopter and then proceed to develop new algorithms for control and sensing using the simulation. The work is field-tested in successful flight trials of biologically inspired vision and neural network control for an unstable rotorcraft. The techniques are more robust and more easily implemented on a small flying vehicle than previously attempted methods.¶ Experiments from biology suggest that the sensing of image motion or optic flow in insects provides a means of determining the range to obstacles and terrain. This biologically inspired approach is applied to control of height in a helicopter, leading to the World’s first optic flow based terrain following controller for an unmanned helicopter in forward flight. Another novel optic flow based controller is developed for the control of velocity in hover. Using the measurements of height from other sensors, optic flow is used to provide a measure of the helicopters lateral and longitudinal velocities relative to the ground plane. Feedback of these velocity measurements enables automated hover with a drift of only a few cm per second, which is sufficient to allow a helicopter to land autonomously in gusty conditions with no absolute measurement of position.¶ New techniques for sensor fusion using Extended Kalman Filtering are developed to estimate attitude and velocity from noisy inertial sensors and optic flow measurements. However, such control and sensor fusion techniques can be computationally intensive, rendering them difficult or impossible to implement on a small unmanned vehicle due to limitations on computing resources. Since neural networks can perform these functions with minimal computing hardware, a new technique of control using neural networks is presented. First a hybrid plant model consisting of exactly known dynamics is combined with a black-box representation of the unknown dynamics. Simulated trajectories are then calculated for the plant using an optimal controller. Finally, a neural network is trained to mimic the optimal controller. Flight test results of control of the heave dynamics of a helicopter confirm the neural network controller’s ability to operate in high disturbance conditions and suggest that the neural network outperforms a PD controller. Sensor fusion and control of the lateral and longitudinal dynamics of the helicopter are also shown to be easily achieved using computationally modest neural networks.
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Kang, Yong Suk. "Development of Predictive Vehicle Control System using Driving Environment Data for Autonomous Vehicles and Advanced Driver Assistance Systems." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/85106.

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In the field of modern automotive engineering, many researchers are focusing on the development of advanced vehicle control systems such as autonomous vehicle systems and Advanced Driver Assistance Systems (ADAS). Furthermore, Driver Assistance Systems (DAS) such as cruise control, Anti-Lock Braking Systems (ABS), and Electronic Stability Control (ESC) have become widely popular in the automotive industry. Therefore, vehicle control research attracts attention from both academia and industry, and has been an active area of vehicle research for over 30 years, resulting in impressive DAS contributions. Although current vehicle control systems have improved vehicle safety and performance, there is room for improvement for dealing with various situations. The objective of the research is to develop a predictive vehicle control system for improving vehicle safety and performance for autonomous vehicles and ADAS. In order to improve the vehicle control system, the proposed system utilizes information about the upcoming local driving environment such as terrain roughness, elevation grade, bank angle, curvature, and friction. The local driving environment is measured in advance with a terrain measurement system to provide terrain data. Furthermore, in order to obtain the information about road conditions that cannot be measured in advance, this work begins by analyzing the response measurements of a preceding vehicle. The response measurements of a preceding vehicle are acquired through Vehicle-to-Vehicle (V2V) or Vehicle-to-Infrastructure (V2I) communication. The identification method analyzes the response measurements of a preceding vehicle to estimate road data. The estimated road data or the pre-measured road data is used as the upcoming driving environment information for the developed vehicle control system. The metric that objectively quantifies vehicle performance, the Performance Margin, is developed to accomplish the control objectives in an efficient manner. The metric is used as a control reference input and continuously estimated to predict current and future vehicle performance. Next, the predictive control algorithm is developed based on the upcoming driving environment and the performance metric. The developed system predicts future vehicle dynamics states using the upcoming driving environment and the Performance Margin. If the algorithm detects the risks of future vehicle dynamics, the control system intervenes between the driver's input commands based on estimated future vehicle states. The developed control system maintains vehicle handling capabilities based on the results of the prediction by regulating the metric into an acceptable range. By these processes, the developed control system ensures that the vehicle maintains stability consistently, and improves vehicle performance for the near future even if there are undesirable and unexpected driving circumstances. To implement and evaluate the integrated systems of this work, the real-time driving simulator, which uses precise real-world driving environment data, has been developed for advanced high computational vehicle control systems. The developed vehicle control system is implemented in the driving simulator, and the results show that the proposed system is a clear improvement on autonomous vehicle systems and ADAS.
Ph. D.
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27

Rickenbach, Mark Douglas. "Correction of inertial navigation system drift errors for an autonomous land vehicle using optical radar terrain data." Thesis, Monterey, Calif. : Naval Postgraduate School, 1987. http://hdl.handle.net/10945/22225.

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28

Worley, Marilyn Elizabeth. "Experimental Study on the Mobility of Lightweight Vehicles on Sand." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/34005.

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This study focuses on developing a better comprehension of the mobility of lightweight autonomous vehicles with varying locomotion platforms on sand. This research involves four segments.

The first segment is a review of military criteria for the development of lightweight unmanned ground vehicles, followed by a review a review of current methodologies for evaluating the terramechanic (vehicle-ground interaction) mobility measures of heavyweight wheeled and tracked vehicles, and ending with a review of the defining properties of deformable terrain with specific emphasis on sand. These present a basis for understanding what currently defines mobility and how mobility is quantified for traditional heavyweight wheeled and tracked vehicles, as well as an understanding of the environment of operation (sandy terrain) for the lightweight vehicles in this study.

The second segment involves the identification of key properties associated with the mobility and operation of lightweight vehicles on sand as related to given mission criteria, so as to form a quantitative assessment system to compare lightweight vehicles of varying locomotion platforms. A table based on the House of Quality shows the relationships—high, low, or adverse—between mission profile requirements and general performance measures and geometries of vehicles under consideration for use. This table, when combined with known values for vehicle metrics, provides information for an index formula used to quantitatively compare the mobility of a user-chosen set of vehicles, regardless of their methods of locomotion. This table identifies several important or fundamental terramechanics properties that necessitate model development for robots with novel locomotion platforms and testing for lightweight wheeled and tracked vehicles so as to consider the adaptation of counterpart heavyweight terramechanics models for use.

The third segment is a study of robots utilizing novel forms of locomotion, emphasizing the kinematics of locomotion (gait and foot placement) and proposed starting points for the development of terramechanics models so as to compare their mobility and performance with more traditional wheeled and tracked vehicles. In this study several new autonomous vehicles—bipedal, self-excited dynamic tripedal, active spoke-wheel—that are currently under development are explored.

The final segment involves experimentation of several lightweight vehicles and robots on sand. A preliminary experimentation was performed evaluating a lightweight autonomous tracked vehicle for its performance and operation on sand. A bipedal robot was then tested to study the foot-ground interaction with and sinkage into a medium-grade sand, utilizing a one of the first-developed walking gaits. Finally, a comprehensive set of experiments was performed on a lightweight wheeled vehicle. While the terramechanics properties of wheeled and tracked vehicles, such as the contact patch pressure distribution, have been understood and models have been developed for heavy vehicles, the feasibility of extrapolating them to the analysis of light vehicles is still under analysis. A wheeled all-terrain vehicle was tested for effects of sand gradation, vehicle speed, and vehicle payload on measures of pressure and sinkage in the contact patch, and preliminary analysis is presented on the sinkage of the wheeled all-terrain vehicle.

These four segments—review of properties of sandy terrain and measures of and criteria for the mobility of lightweight vehicles operating on sandy terrain, the development of the comparison matrix and indexing function, modeling and development of novel forms of locomotion, and physical experimentation of lightweight tracked and wheeled vehicles as well as a bipedal robot—combine to give an overall picture of mobility that spans across different forms of locomotion.
Master of Science

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Hofmeyr, Melanie Kemp. "Modified simplification of HDM-4 methodology for the calculation of vehicle operating cost to incorporate terrain and expanded to all vehicle types for use in the Western Cape context F HDM-4 METHODOLOGY FOR THE CALCULATION OF VEHICLE OPERATING COST TO INCORPORATE TERRAIN AND EXPANDED TO ALL VEHICLE TYPES FOR USE IN THE WESTERN CAPE CONTEXT." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96824.

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Thesis (MSc)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: INTRODUCTION The Western Cape Government (WCG) uses Vehicle Operating Cost (VOC) as part of their Road Management System since 1992. VOC is used in the process of prioritisation of maintenance projects as well as for the identification of economically viable maintenance strategies and is thus an integral part of the system. In 2001 changes to the VOC calculation methodology in the system to Highway Development and Management (HDM-4) system methodology occurred. The reasons were twofold – to bring the calculation method in line with world trends and due to lack of updated cost factors used in the previous methodology. In October 2001 a model was implemented with riding quality (IRI) as independent variable. This model was partly based on regression table data. As no geometric/topography data, defined as Terrain data, was available at this stage, Terrain was ignored. In 2006 WCG Systems were updated with Global Positioning System (GPS) data and a process to classify or categorise Terrain was initiated, thus providing the opportunity to include Terrain. As part of the redevelopment to include Terrain, it was decided to re-evaluate the vehicle fleet. METHODOLOGY Various alternative methods to develop the Modified Simplification equations were available and evaluated, e.g. regression or direct mathematical substitution. HDM-4 requires the input of Vehicle Type dependent cost parameters that is based on real vehicles. The WCG required that changes to these dependent parameters is feasible, so that they can be updated periodically. A set of equations therefore needed to be developed, allowing the input of Vehicle Type dependent parameters and the subsequent calculation of VOC with riding quality (IRI) as independent variable. This renders the use of regression analysis untenable. Composition of the vehicle fleet on each road section is required to utilise HDM-4 for analyses. In order to simplify calculations, different traffic strata was defined, i.e. Business, Commuter, Rural and General. In the evaluation of the Vehicle it is this strata and data from permanent counting stations that is used to compile a Vehicle fleet. MODEL DEVELOPMENT The Modified Simplification to include Terrain results in 48 combinations of Vehicle Type, Surface Type and Terrain Type for the basic equation of VOC. VOC = TCav + PARTSCOST + LABOURCOST +DEPCSTav ( )´ Length of road segment 1000 +(FuelCostav +OilCostav )´ Length of road segment av TC -Tyre Cost PARTSCOST -Parts Cost LABOURCOST - Labour Cost av DEPCST - Depreciation Cost av FuelCost -Fuel Cost av OilCost - Oil Cost The variables in VOC are defined by a couple of equations. For explanatory purposes a numeric example is presented. CONCLUSION AND RECOMMENDATION The implementation of this Modified Simplification has assisted not only the WCG, but also other entities, that also use the VOC (published annually) based on these principles. Interested parties have the option to include Terrain in their implementation. Caution should be taken when using the Modified Simplification, as it is important that the principles used to simplify HDM-4 apply to the implementation and the business rules of the Management system of the user. The current development will not require a redevelopment due to any vehicle fleet change in future as the decision to simplify all defined Vehicle Types in HDM-4 allows the new fleet to be updated. Recommendation for further research and development include: • Standalone function that is already considered by the WCG • Investigating Published Vehicle data • Economic vehicle data for use in specific applications
AFRIKAANSE OPSOMMING: INLEIDING Sedert 1992 gebruik die Wes-Kaapse Regering (WCG) voertuiggebruikskoste (VOC) as deel van hul Plaveisel Bestuurstelsels. VOC word gebruik in die proses van prioritisering van die instandhoudingprojekte sowel as vir die identifisering van ekonomies-vatbare instandhouding-strategieë en is dus 'n integrale deel van die stelsel. In 2001 is daar besluit om oor te skakel na die berekeningsmetode van Highway Development and Management (HDM-4). Die redes was tweeledig – om die berekeningsmetode in lyn met die wêreld tendense te bring; en as gevolg van 'n gebrek aan opgedateerde koste-faktore in die voorheen-gebruikte metode. In Oktober 2001 is 'n VOC-model, met rygehalte (IRI) as onafhanklike veranderlike geïmplementeer. Hierdie model was gedeeltelik gebaseer op regressie tabel data. Aangesien daar geen geometriese/topografiese data (gedefiniëer as terreindata) beskikbaar was nie, is die terrein geïgnoreer. In 2006 is WCG Stelsels opgedateer met Globale Positionering Stelsel (GPS) data en 'n proses om terrein te klassifiseer is van stapel gestuur. Deur die verandering in beskikbare data, is die geleentheid om terrein in te sluit in die VOC model geskep. As deel van die insluiting van herontwikkeling om terrein in te sluit, is daar besluit om die voertuigvloot te her-evalueer. METODOLOGIE Verskeie alternatiewe metodes om die Gewysigde Vereenvoudiging-vergelykings te ontwikkel was beskikbaar en is geëvalueer, bv. regressie of direkte wiskundige vervanging en vereenvoudiging. HDM-4 se voertuigafhanklike koste-parameters is op werklike voertuie gebaseer. Die WCG het vereis dat hierdie afhanklike parameters veranderbaar moet wees, sodat hulle dit van tyd tot tyd kan opdateer. Dit was dus nodig om 'n stel vergelykings te ontwikkel met die tipe voertuigkosteafhanklike parameters as insette. Verder moes alle vergelykings weer in terme van rygehalte wees. Dit maak die gebruik van regressie-analise ononderhoubaar. Samestelling van die voertuigvloot op elke padseksie is 'n vereiste om HDM-4 aan te wend vir ontledingsdoeleindes. Ten einde berekeninge te vereenvoudig is verskillende verkeerstrata gedefinieer, naamlik Besigheid, Pendel, Landelik en Algemeen. In die evaluering van die Voertuig is dit hierdie strata en data uit permanente telstasies wat gebruik word om 'n voertuigvloot saam te stel. MODELONTWIKKELING Die Gemodifiseerde Vereenvoudiging, insluitend terrein, het 48 kombinasies van tipe voertuig, oppervlak en terrein vir die basiese vergelyking van VOC: VOC = TCav + PARTSCOST + LABOURCOST +DEPCSTav ( )´ Length of road segment 1000 +(FuelCostav +OilCostav )´ Length of road segment TCav - Bandkoste; PARTSCOST - Onderdele-koste; LABOURCOST - Arbeidskoste; av FuelCost - Brandstofkoste; av DEPCST - Waardeverminderingskoste; av OilCost - Oliekoste Die veranderlikes in VOC word gedefinieer deur 'n paar vergelykings. Vir verduidelikende doeleindes word 'n numeriese voorbeeld ingesluit. GEVOLGTREKKING EN AANBEVELING Die implementering van hierdie Gewysigde Vereenvoudiging het nie net die WCG nie, maar ook ander entiteite wat ook die VOC (jaarliks gepubliseer) gebruik, bygestaan. Belangstellendes het die opsie om die terrein in hul implementering in te sluit. Dit is belangrik om ag te slaan op die beginsels wat gebruik is om HDM-4 te vereenvoudig tesame met die besigheidsreëls van die Gewysigde Vereenvoudiging, indien dit gebruik word. Die huidige model vereis nie 'n herontwikkeling as gevolg van enige voertuigvloot verandering in die toekoms nie. As gevolg van die besluit om alle gedefinieerde tipes voertuig te vereenvoudig, kan die voertuigvloot keuse net in die stelsel opgedateer word. Aanbeveling vir verdere navorsing en ontwikkeling sluit in: • Alleenstaande funksie wat reeds deur die WCG beskou word • Ondersoek Gepubliseerde Voertuig data • Gebruik van Ekonomiese voertuigdata vir sekere toepassings
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30

Åström, Charlotte. "Effects of vibration on muscles in the neck and upper limbs : with focus on occupational terrain vehicle drivers." Doctoral thesis, Umeå universitet, Institutionen för samhällsmedicin och rehabilitering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1668.

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Introduction: Occupational drivers of terrain vehicles are exposed to several risk factors associated with musculoskeletal symptoms in the lower back as well as in the neck and upper limbs. Vibration has been suggested to be a main risk factor. These drivers are exposed to both whole-body vibration (WBV) and hand-arm vibration (HAV). Aim: This study establishes the association between driving terrain vehicles and musculoskeletal disorders (MSDs) in the neck and upper limbs as well as hand-arm vibration syndrome (HAVS). In addition, this study examines the effect on muscles in the neck and upper limbs of the type of vibration exposure that occurs in occupational driving of terrain vehicles. Methods and results: In Paper I, a cross-sectional questionnaire study on occupational drivers of terrain vehicles, increased Prevalence Odds Ratios (POR) were found for numbness, sensation of cold and white fingers (POR 1.5-3.9) and for MSDs in the neck (POR 2.1-3.9), shoulder (POR 1.8-2.6) and wrist (POR 1.7-2.6). For the shoulders, neck and elbow, there appears to be a pattern of increased odds with increasing exposure time. In Paper II, an experimental study on the trapezius muscle, which included 20 men and 17 women, the mean frequency of the electromyography signal (EMGMNF) decreased significantly more in a three minute sub-maximal contraction without vibration (-3.71Hz and -4.37Hz) compared to with induced vibration (-3.54Hz and -1.48Hz). In Paper III, a higher initial increase of the mean of the root-mean-square of the electromyography signal (EMGRMS) was seen in a three minute sub-maximal contraction with vibration exposure compared to without vibration (0.096% vs. 0.045%). There was a larger mean EMGMNF decrease for NV compared to V in the total three minutes, and a larger decrease also in the first time period was seen for the NV compared to V. A small gender effect was also noticed. In Paper IV, the combination of HAV and WBV was studied in laboratory settings and resulted in a higher trapezius EMGRMS compared to the HAV and WBV separately. Conclusion: Occupational drivers of terrain vehicles are likely to experience symptoms related to HAVS and musculoskeletal symptoms in the neck and upper limbs. Local vibration does not seem to have any negative acute effects on trapezius muscle fatigue. Vibration exposure seems to cause an initial increase in muscle activity in the trapezius that could be related to recruitment on new motor-units. A combination of HAV and WBV causes a larger muscular demand on the trapezius muscle.
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Khakimbayev, Jasur S. "Development of integrated 3D terrain maps for Unmanned Aerial Vehicle (UAV) Flight and Mission Control Support System (FMCSS)." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2006. http://library.nps.navy.mil/uhtbin/hyperion/06Mar%5FKhakimbayev.pdf.

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Thesis (M.S. in Modeling, Virtual Environments, and Simulation (Moves))--Naval Postgraduate School, March 2006.
Thesis Advisor(s): Wolfgang Baer, Curtis L. Blais. "March 2006." Includes bibliographical references (p.99-101). Also available online.
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Engh, Cameron Howard. "A See-ability Metric to Improve Mini Unmanned Aerial Vehicle Operator Awareness Using Video Georegistered to Terrain Models." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2664.pdf.

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33

Parvathareddy, Bhavana. "STATISTICAL ANALYSIS OF INJURY DATA AND THE CONCEPTUAL DESIGN OF A ROLLOVER PROTECTIVE STRUCTURE FOR AN ALL-TERRAIN VEHICLE." UKnowledge, 2005. http://uknowledge.uky.edu/gradschool_theses/347.

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The rising statistics of fatal and non-fatal injuries involving an all-terrain vehicle has called for an analysis of the accumulated data from the past years. The analysis has led to the conclusion that in the past years, the fatal and non-fatal injuries have been rising rapidly in spite of the consent decrees which were brought into effect from 1988-1998 by the consumer product safety commission. A necessity to provide increased safety while riding an all-terrain vehicle is recognized. Rollover protective structures which were used with successful results in curbing the injuries on agricultural tractors have been identified as having a potential to serve the purpose. A conceptual design of an automatically deployable rollover protective structure has been dealt with, in the thesis.
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34

Taheri, Shahyar. "A Hybrid Soft Soil Tire Model (HSSTM) For Vehicle Mobility And Deterministic Performance Analysis In Terramechanics Applications." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/76654.

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Accurate and efficient tire models for deformable terrain operations are essential for performing vehicle simulations. Assessment of the forces and moments that occur at the tire-terrain interface, and the effect of the tire motion on properties of the terrain are crucial in understanding the performance of a vehicle. In order to model the dynamic behavior of the tire on different terrains, a lumped mass discretized tire model using Kelvin-Voigt elements is developed. To optimize the computational time of the code, different techniques were used in memory allocation, parameter initialization, code sequence, and multi-processing. This has resulted in significant improvements in efficiency of the code that can now run close to real time and therefore it is suitable for use by commercially available vehicle simulation packages. Model parameters are obtained using a validated finite element tire model, modal analysis, and other experimental test procedures. Experimental tests were performed on the Terramechanics rig at Virginia Tech. The tests were performed on different terrains; tire forces and moments, soil sinkage, and tire deformation data were collected for various case studies based on a design of experiment matrix. This data, in addition to modal analysis data were used to validate the tire model. Furthermore, to study the validity of the tire model, simulations at conditions similar to the test conditions were performed on a quarter car model. The results have indicated the superiority of this model as compared to other lumped parameter models currently available.
Ph. D.
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35

Peterson, Bryan. "Integration of deformable tire-soil interaction simulation capabilities in physics-based off-road mobility solver." Thesis, University of Iowa, 2016. https://ir.uiowa.edu/etd/2258.

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The objective of this study is to integrate a continuum-based deformable tire and terrain interaction model into a general-use physics-based simulation environment capable of off-road vehicle mobility analysis and high-performance computing potential. Specifically, the physics-based deformable tire and terrain models which were recently proposed and validated by Yamashita, et al. will be implemented into the structure of the multi-physics simulation engine Chrono. In off-road vehicle mobility analysis, empirical and analytical models have been commonly used for vehicle-terrain interaction. While these models utilize experimental data or terramechanics theories to create quick predictive mobility models, they are unable to capture the highly nonlinear behavior of soft soil deformation, which can lead to inaccurate or unreliable results. In order to resolve these limitations, the use of physics-based numerical approaches have been proposed. These methods make use of finite element and discrete element simulations to describe the interaction between the vehicle and deformable terrain. Continuum-based finite element models transfer tire forces to the terrain and model the deformation with elasto-plastic constitutive models. Discrete element soil uses a large number of small rigid body particles to describe the microscale behavior of granular terrain, with the deformation of the soil represented by the motion and contact of the particles. While these physics-based models offer a more accurate vehicle-terrain interaction model, the solution procedure can become complex and computationally expensive since co-simulation techniques are often used. To address these issues, the analysis of physics-based full vehicle dynamics simulations utilizing high-fidelity deformable tire and terrain models in a multi-physics engine with high-performance computing capability is desired. To this end, a continuum mechanics based shear deformable laminated composite shell element proposed by Yamashita, et al. was integrated into the flexible body dynamics simulation framework of Chrono. This element was based on the absolute nodal coordinate formulation and is defined by the global position coordinates and the transverse gradient coordinates of its four nodes. Element lockings are eliminated with the incorporation of the enhanced assumed strain (EAS) and assumed natural strain approaches (ANS). The element formulation includes an extension to model laminated composite materials. Additionally, a locking-free 9-node brick element was integrated into the Chrono framework that makes use of the curvature coordinates at the center of the element. This element is formulated with the Hencky strain measure such that multiplicative finite strain plasticity theory can be used to incorporate soil plasticity models, such as the capped Drucker-Prager failed criterion. With the shear deformable laminated composite shell element and plastic soil brick element integrated into the Chrono multi-physics simulation engine, an off-road deformable tire and terrain interaction model was developed using the vehicle dynamics simulation module Chrono::Vehicle. An off-road deformable tire model was parameterized based on commercial tire properties and generated as an interchangeable tire model option in the full vehicle dynamics system. Benchmark verification tests were performed to ensure the accuracy of tire deformation and tire force characteristics. Further tests were performed to validate a deformable tire model with a deformable tread pattern constructed from shear deformable shell elements and co-rotational tetrahedral elements. The deformable soil model was also integrated as a terrain option in Chrono::Vehicle and numerical tests were carried out to demonstrate its interaction with rigid and deformable tire models. To make use of the computational performance enhancements available in Chrono, Open Multi-Processing (OpenMP) and Advanced Vector Extensions (AVX) were applied to the evaluation of the elastic force/Jacobian matrix and large matrix operations of flexible bodies, respectively, in order to reduce the computation time by nearly 60%.
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Baillie, Allan Stuart. "Development of a fuzzy logic controller for an active suspension of an off-road vehicle fitted with terrain preview." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0004/MQ44897.pdf.

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37

Osborne, William Dale. "NPSNET : an accurate low-cost technique for real-time display of transient events : vehicle collisions, explosions and terrain modifications." Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/26651.

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38

Wallace, Shane Alan. "DEVELOPMENT OF A SMALL AND INEXPENSIVE TERRAIN AVOIDANCE SYSTEM FOR AN UNMANNED AERIAL VEHICLE VIA POTENTIAL FUNCTION GUIDANCE ALGORITHM." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/380.

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Despite the first unmanned aerial vehicle (UAV) mission being flown on Aug 22 1849 to bomb Venice UAVs have only recently began to modernize into sophisticated tools beyond simple aerial vehicles. With an increasing number of potential applications, such as cargo delivery, communications, search and rescue, law enforcement, and homeland security, the need for appropriate UAV technology advancement also arose. Here, the development of a low-cost collision avoidance system is described. Hardware was tested and selected based on predetermined constraints and goals. Additionally, a variety of potential functions were explored and assessed at their effectiveness in preventing a collision of a UAV with mountainous terrain. Simulations were conducted using Cloud Cap’s Piccolo autopilot in conjunction with Matlab. Based on these simulations, a set of potential functions was selected to be used with the chosen hardware on subsequent UAV-development-related projects.
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Matthews, Patricia Aileen 1963. "Validation of a vehicle mobility computer model for heavy earthmoving equipment." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/276946.

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The computer program WHEEL is a mathematical model which predicts off-road vehicle performance characteristics. The program was developed using empirical relationships resulting from mobility tests on conventional-sized trucks and tires. The model was subsequently validated by comparing the model's predicted values of vehicle performance parameters, such as net drawbar pull, slip, sinkage and torque, with field test results for conventional-sized vehicles. However, validity of the model for predicting the off-road mobility of vehicles with large diameter tires was not established. The purpose of this study was to provide this validation. Values of net drawbar pull and slip for a Case 2390 tractor with 70.2" diameter driven wheels predicted by computer program WHEEL compare favorably with traction data obtained from tractor performance tests conducted by the University of Arizona Department of Agricultural Engineering. Therefore, the model may be used confidently to analyze performance of vehicles with large diameter wheels.
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40

Wiet, Christopher J. "Energy Optimization of an In-Wheel-Motor Electric Ground Vehicle over a Given Terrain with Considerations of Various Traffic Elements." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397045426.

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41

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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42

OSTERMAN, NILAS. "Finding the most suitable auxiliary sonar for terrain-aided navigation and behavior-fusion based obstacle avoidance for an autonomous underwater vehicle." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-263287.

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Autonomous underwater vehicles are rapidly becoming more common and developed for both military as well as civilian applications such as; mine countermeasures or in the field of geoscience. One of the main issues these vehicles are facing today is the navigation capability. Since they operate in an underwater environment, modern navigation strategies such as GPS and radar are not available due to the quick attenuation of the high frequency signals. The most commonly used navigation strategy is the dead-reckoning navigation which estimates the location of the vehicle using sensor data and numerical integration. The disadvantage with this technique is the accumulative errors during longer operation times. Terrain-aided navigation has been extensively researched as of late and deemed as a viable approach to compensate for the errors when using dead-reckoning navigation. This type of navigation uses a predefined map of the bathymetry and estimates the position of the vehicle on the map using a particle filter and bathymetry measurements from the sonars attached to the vehicle. This project is focused on finding the most suitable auxiliary sonar for the underwater vehicle which enables accurate terrainaided navigation with regards to physical limitations such as the weight, resolution, power consumption and accuracy of the sonar. The sonars to be tested are a single-beam echo sounder, multiple singe-beam echo sounders, multi-beam echo sounder and a 2.5D sonar. The four different sonars are tested with the terrain-aided navigation algorithm where a vehicle simulator developed by Saab is used for the simulations. The results show that the multiple single-beam echo sounder configuration is the most suitable solution due to its high accuracy during the navigation and its low impact on the system dynamics and power consumption. The chosen sonar configuration is later integrated together with a behavior-fusion algorithm to achieve reliable obstacle avoidance capabilities for the vehicle. The algorithm uses a weighted mean-value of the sonar beams to identify approaching obstacles as well as a bathymetry derivative estimation to make the system more adaptive to its surroundings. The vehicle was able to detect incoming obstacles ahead and to the sides of the vehicle up to 17 seconds earlier compared to when only using a doppler velocity log.
Autonoma undervattensfarkoster håller just nu på att slå igenom på bred front inom både militära och civila tillämpningar såsom; minjakt eller inom geovetenskap. Ett av de största problemen denna typ av farkoster har idag är förmågan att säkert navigera under uppdragen. Då de används i en undervattensmiljö så kan inte moderna navigationsmetoder såsom GPS eller radar användas då högfrekventa signaler dämpas snabbt. Den vanligaste typen av navigation är död räkning, vilket estimerar farkostens position genom användning av sensor data och numerisk integration. Nackdelen med denna typ av teknik är de ackumulerade felen som uppstår under längre körningar. På senare tid har terrängnavigering varit i fokus inom forskningen och anses vara en bra lösning för att kompensera för positionsfelen som uppstår vid navigation med död räkning. Denna typ av navigation använder sig av en fördefinierad karta över batymetrin och estimerar farkostens position relativt kartan med hjälp av ett partikel filter och batymetrimätningar från sonarer moneterade på farkosten. Detta projekt fokuserar på att hitta den mest passade sonaren för farkosten som gör det möjligt att använda terrängnavigering med hög precision då fysiska aspekter såsom, vikt, upplösning, strömförbrukning och noggranheten av sonaren tas till hänsyn. Sonarerna som skall testas består av; ett enstråligt ekolod, flera enstråliga ekolod, ett flerstråligt ekolod och en 2.5D sonar. De fyra sonarerna testas med terrängnavigeringsalgoritmen, där en simulator av farkosten utvecklad av Saab används som grund för simuleringarna. Resultaten visar att användningen av flera enstråliga ekolod är den mest passade lösningen då den resulterar i väldigt god navigationsförmåga med låg inverkan på farkostens strömförbrukning och dynamik jämfört med de andra alternativen. Den valda sonaren används sedan tillsammans med en behaviour-fusion baserad algoritm för att farkosten skall uppnå pålitlig hinderundvikning. Algoritmen använder sig av ett viktat medelvärde av sonarstrålarna för att identifiera närmade hinder tillsammans med en uppskattning av batymetrins derivata för att få en mer adaptiv hinderundvikning. Farkosten kunde med hjälp av behaviour-fusion algoritmen och de flerstråliga ekoloden identifiera närmande objekt upp till 17 sekunder tidigare än om bara en doppler velocity log användes.
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43

Jakubík, Norbert. "Design elektrického užitkového terénního vozidla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-232067.

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The subject of this diploma thesis is to create a new interesting design of electric utility terrain vehicle in accordance with technical, ergonomic and aesthetic requirements for such product. My main aim is to create an innovative design concept of terrain vehicle with utility dump bed and seats for two passengers.
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44

Vickous, Kim Elaine Young. "An All-Terrain Vehicle Safety Educational Program: Is It Effective in Improving Attitudes, Safety Knowledge, and Behaviors in Adolescents Ages 12 to 18?" TopSCHOLAR®, 2008. http://digitalcommons.wku.edu/theses/23.

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All terrain vehicles (ATVs) are a popular source of recreation. For some rural adolescents, ATVs are frequently used for agricultural work. Whether for work or recreation, many adolescents operate ATVs improperly either from a lack of knowledge, poor judgment or they engage in risky behaviors resulting in injuries and fatalities. The Kentucky Department of Agriculture (KDA) has devoted resources to provide ATV safety programs to educate adolescents statewide. However, there are no known studies evaluating the effectiveness of this KDA intervention. Therefore, a pilot study was proposed to determine the effectiveness of The KDA ATV safety program in improving ATV safety knowledge, attitudes and behaviors of adolescents ages 12 to 18. Following HSRB approval, a pre-experimental one group, pre-test, post-test design pilot study was conducted. A convenience sample (n=18) was drawn from adolescents registered to attend an ATV safety program provided by the KDA. The study was conducted in a south central Kentucky city. Haddon’s Matrix was used as the theoretical framework using the dual axis approach to injury prevention and injury control. On one axis are the host, the agent and the environment. In this study the host is the adolescent ATV driver, and the agent is the all-terrain vehicle. The environment includes the terrain, applicable ATV laws and societal attitudes toward ATV safety. On the second axis are the pre-event, event and post-event phases. Haddon’s Matrix is a process mechanism in which opportunities to reduce ATV related injuries and fatalities can be identified. It is believed that knowledge, attitudes and behaviors regarding ATV safety can be positively influenced through effective educational strategies, ATV engineering design changes and ATV law enforcement issues as identified through the use of Haddon’s Matrix. Descriptive statistics and paired t-tests were used to analyze the data. The analysis revealed no statistically significant changes in adolescent knowledge following the intervention. However, there were statistically significant improvements in ATV related safety attitudes and behaviors. In conclusion, efforts should continue to prevent ATV-related injuries and fatalities via educational strategies to change behaviors and attitudes regarding ATV safety in communities and individuals. Implications include the need for further research to determine best practice ATV educational strategies that create positive change.
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45

Mihálik, Boris. "Terénní čtyřkolový motocykl pro seniory." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2014. http://www.nusl.cz/ntk/nusl-231447.

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This diploma thesis deals with the design and realization of function pattern of off-road four-wheel vehicle for seniors. First part of the work consist of research of current commercial vehicles for the elderly, as well as small four-wheeled off-road vehicles and their individual design elements. In this part of the work were also dismantled the proposed legislation allowing legal movement of vehicles on public roads and seniors ergonomics. Another section dealt with the proposal of possible variants for solving the essential structural elements of the vehicle. The last major parts of the work deals with detail description of each selected construction elements of the vehicle. Functional pattern has been manufactured and tested. At the end of this work were published the results of testing of the vehicle and also were proposed possible changes of design.
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46

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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47

Horák, Martin. "Design terénního vozidla." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-232065.

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The main goal of this diploma thesis is to create a design of an off-road vehicle. The vehicle has become a concept vision of an ecological off-road of the future fueled by hydrogen fuel cells. The secondary goal is: to bring new innovative form elements into conventional design solution of off-road vehicles and to highlight the problem with ecology, environmental protection and limited resources of fossil fuels.
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48

Nygren, Ingemar. "Terrain navigation for underwater vehicles." Doctoral thesis, KTH, School of Electrical Engineering (EES), 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-540.

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In this thesis a terrain positioning method for underwater vehicles called the correlation method is presented. Using the method the vehicle can determine its absolute position with the help of a sonar and a map of the bottom topography. The thesis is focused towards underwater positioning but most of the material is directly applicable to flying vehicles as well. The positioning of surface vehicles has been revolutionized by the global positioning system (GPS). However, since the GPS signal does not penetrate into the sea water volume, underwater vehicles still have to use the inertial navigation system (INS) for navigation. Terrain positioning is therefore a serious alternative to GPS for underwater vehicles for zeroing out the INS error in military applications. The thesis begins with a review of different estimation methods as Bayesian and extended Kalman filter methods that have been used for terrain navigation. Some other methods that may be used as the unscented Kalman filter or solving the Fokker-Planck equation using finite element methods are also discussed. The correlation method is then described and the well known problem with multiple terrain positions is discussed. It is shown that the risk of false positions decreases exponentially with the number of measurement beams. A simple hypothesis test of false peaks is presented. It is also shown that the likelihood function for the position under weak assumptions converges to a Gaussian probability density function when the number of measuring beams tends to infinity. The Cramér-Rao lower bound on the position error covariance is determined and it is shown that the proposed method achieves this bound asymptotically. The problem with measurement bias causing position bias is discussed and a simple method for removing the measurement bias is presented. By adjusting the footprint of the measuring sonar beams to the bottom topography a large increase in accuracy and robustness can be achieved in many bottom areas. This matter is discussed and a systematic theory about how to choose way-points is developed. Three sea-trials have been conducted to verify the characteristics of the method and some results from the last one in October 2002 are presented. The sea-trials verify to a very high degree the theory presented. Finally the method is briefly discussed under the assumption that the bottom topography can be described by an autoregressive stochastic process.

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49

Sköld, Olivia. "Analys av lägesosäkerheter hos fotogrammetriskt framställda DTM - en jämförelse mellan två programvaror." Thesis, Högskolan i Gävle, Samhällsbyggnad, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-32058.

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Idag blir användningen av drönare allt mer vanlig för dokumentation av markytor. Det är ett billigare alternativ för att dokumentera små och otillgängliga områden. Genom tekniken går det bland annat att framställa olika digitala modeller som representerar jordens yta. En sådan modell kan vara en terrängmodell (DTM) som är en modell av markytan exklusive vegetation, hus eller annat som befinner sig på marken. Modeller kan framställas genom flygdata såsom laserskannad (LiDAR-data) eller flygfotograferade data (flygbilder). För att framställa en digital modell från rådata används olika programvaror. Den här studien utvärderar två olika programvarors förmåga att framställa digitala terrängmodeller från flygbilder. Främst undersöks levererade osäkerheter och användarvänligheten i programmen. Referensdata som användes i denna studie tillhandahölls av Norconsult och samlades in vid ett projekt över Hammarbyhöjdsskogen i Stockholm, hösten 2018. Den data som erhölls från projektet till denna studie var flygbilder samt terrestra detaljmätningar. Programmen som studien utvärderar är UAS Master som både använder datorseende och fotogrammetriska metoder och SURE Aerial som använder datorseende. Genom studien visade det sig att fler än de ursprungliga programvarorna behövdes för att framställa de digitala terrängmodellerna och vidare jämföra dessa. En orsak var att UAS Master saknade förmågor att redigera och visa punktmoln i 3D-vy och vidare skapa en DTM. Detta resulterade i att använda Trimble Business Center för slutarbetet. En annan orsak var att SURE Aerial visade sig vara avsett för framställning av digitala ytmodeller (representation av den faktiska, synliga ytan). För att framställa en DTM av punktmolnet användes både Cloud Compare och Agisoft Photoscan (numera Metashape). Geo användes sedan för att ta ut höjdavvikelserna från modellen. Två slutsatser som kunde dras utifrån denna studie var: 1) trots de olika tillvägagångssätten erhölls snarlika resultat för marktypernas lägesosäkerheter för respektive programvara (asfalt: 0,039 m; grus: ca 0,040 m; gräs: ca 0,048 m), varpå alla blev godkända enligt HMK – Flygfotografering 2017; 2) SURE Aerial är ett enklare och snabbbare program men med UAS Master har man som användare bättre förståelse över processerna och erhåller bättre dokumentation.
Drones have become a more and more frequent tool to document the surface of the ground, especially in smaller areas that otherwise are too expensive to observe by other means. This technology makes it possible to create digital terrain models (DTM) that represents the surface of the ground excluding vegetation, houses or other objects on the ground. These models can be created by laser scanned data (LiDAR-data) or aerial photogrammetry (aerial photos).  In order to create a digital model from raw data are various software needed. This study aims to test two software’s ability to create digital terrain models from UAS photos. The software were evaluated by the uncertainties of the models, as well as the user-friendliness of each software. All data used in this study was collected by Norconsult for another project in 2018 and consist of UAS photos and data from terrestrial measurements.  The softwares used in this study for comparison are UAS Master (using both computer vision and photogrammetric methods) and SURE Aerial (using computer vision). It turned out that additional use of software were needed to create DTMs that were comparable. UAS Master could not show or edit point clouds in 3D, because of this the software Trimble Business Centre had to be used. This program was also used to obtain height deviations. SURE Aerial on the other hand turned out to only be able to create digital surface models (models of the visible ground). The software Cloud Compare and Agisoft Photoscan (nowadays Metashape) were therefore used to create the DTM from the point cloud. The height deviations from the ladder DTM were obtained from the software Geo. Two conclusions could be drawn from this study: 1) the uncertainties of the different surface types were similar in the software despite the different ways to create the DTMs (asphalt: 0.039 m; gravel: 0.040 m; grass: 0.048 m). All of which meet the requirements according to HMK – Flygfotografering 2017; 2) SURE Aerial is a lot easier and quicker to work with but UAS Master give the user a lot more feedback in the way of documentation throughout the different processes.
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Curtis, Andrew B. "Path Planning for Unmanned Air and Ground Vehicles in Urban Environments." Diss., CLICK HERE for online access, 2008. http://contentdm.lib.byu.edu/ETD/image/etd2270.pdf.

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