Journal articles: 'Longitudinal dynamics'

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Spiryagin, Maksym, Qing Wu, and Colin Cole. "Longitudinal train dynamics." Vehicle System Dynamics 55, no. 4 (2017): 449. http://dx.doi.org/10.1080/00423114.2017.1285510.

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CLOVER, C. L., and J. E. BERNARD. "Longitudinal Tire Dynamics." Vehicle System Dynamics 29, no. 4 (1998): 231–60. http://dx.doi.org/10.1080/00423119808969374.

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Oleksij, Fomin, Lovska Alyona, Kovtun Oleksandr, and Nerubatskyi Volodymyr. "DEFINING PATTERNS IN THE LONGITUDINAL LOAD ON A TRAIN EQUIPPED WITH THE NEW CONCEPTUAL COUPLERS." Eastern-European Journal of Enterprise Technologies 2, no. 7 (104) (2020): 33–40. https://doi.org/10.15587/1729-4061.2020.198660.

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The longitudinal-dynamic load on a railroad train has been studied at its steady motion along the track of a homogeneous profile. A value of the longitudinal loading that a train is exposed to has been established. The calculations were carried out for a train consisting of 40 similar semi-wagons. The magnitude of the longitudinal loading, in this case, is taken to equal 1.2 MN. It is important to note that when increasing the motion speed, as well as the weight of a train, the magnitude of the longitudinal load may exceed the specified value. This contributes to the additional loading on the bearing structures of cars on the train and can cause damage to them. In addition, significant longitudinal-dynamic loads contribute to disrupting the motion stability of cars in the train. In order to reduce the longitudinal-dynamic efforts in the train under operating modes, including braking, it has been proposed to use, instead of a standard automatic coupling device, a conceptual coupler. In this case, the impact's kinetic energy is damped by transforming it into the work of a viscous resistance force. This resistance is created by moving a viscous liquid through the throttle holes of the piston based on the principle of hydraulic damper operation. To substantiate the use of a conceptual coupler, the calculation has been performed based on a method for determining the strength of the coupling device through the imaginary separation of a train into two parts. Taking into consideration a coefficient of the viscous resistance, which is created by the conceptual coupler, the acceleration experienced by a train reached about 0.8 m/s<sup>2</sup>. In other words, the use of a conceptual coupler makes it possible to reduce the longitudinal loading on a train by almost 30 % compared with the standard scheme of interaction between a locomotive and cars. The rod of the conceptual coupler has been estimated for strength. It has been established that the maximum equivalent stresses do not exceed permissible limits. The proposed measures would contribute to the reduction of a dynamic load on a railroad train under the loading modes of operation. The implementation of a given concept could also contribute to bringing down the damage to railroad stock in exploitation

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CORNELIU, LAZAR, and TIGANASU ALEXANDRU. "Control-Oriented Models for vehicle longitudinal motion." Journal of Engineering Sciences and Innovation 3, no. 3 (2018): 251–64. http://dx.doi.org/10.56958/jesi.2018.3.3.251.

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The use of mathematical models is widespread both in simulating the dynamic behavior of vehicle longitudinal motion and in designing related controllers. This paper focuses on control-oriented models for longitudinal motion which better captured the plant dynamics for vehicles with internal combustion engines. Firstly, a review of some simplified models is presented and secondly, two more complex control-oriented models which take into account the powertrain dynamics are proposed.

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Wu, Qing, Maksym Spiryagin, and Colin Cole. "Longitudinal train dynamics: an overview." Vehicle System Dynamics 54, no. 12 (2016): 1688–714. http://dx.doi.org/10.1080/00423114.2016.1228988.

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Ansari, M., E. Esmailzadeh, and D. Younesian. "Longitudinal dynamics of freight trains." International Journal of Heavy Vehicle Systems 16, no. 1/2 (2009): 102. http://dx.doi.org/10.1504/ijhvs.2009.023857.

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Davydov, Yurii, and Maxim Keyno. "Longitudinal Dynamics in Connected Trains." Procedia Engineering 165 (2016): 1490–95. http://dx.doi.org/10.1016/j.proeng.2016.11.884.

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Müller, Hans-Georg, and Fang Yao. "Empirical dynamics for longitudinal data." Annals of Statistics 38, no. 6 (2010): 3458–86. http://dx.doi.org/10.1214/09-aos786.

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Zhu, Xiaowu, and Li Li. "On longitudinal dynamics of nanorods." International Journal of Engineering Science 120 (November 2017): 129–45. http://dx.doi.org/10.1016/j.ijengsci.2017.08.003.

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Colton, Eugene P. "Longitudinal dynamics in storage rings." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 258, no. 3 (1987): 508–14. http://dx.doi.org/10.1016/0168-9002(87)90934-x.

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Visaya, Maria Vivien, and David Sherwell. "Dynamics from Multivariable Longitudinal Data." Journal of Nonlinear Dynamics 2014 (March 19, 2014): 1–16. http://dx.doi.org/10.1155/2014/901838.

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We introduce a method of analysing longitudinal data in n≥1 variables and a population of K≥1 observations. Longitudinal data of each observation is exactly coded to an orbit in a two-dimensional state space Sn. At each time, information of each observation is coded to a point (x,y)∈Sn, where x is the physical condition of the observation and y is an ordering of variables. Orbit of each observation in Sn is described by a map that dynamically rearranges order of variables at each time step, eventually placing the most stable, least frequently changing variable to the left and the most frequently changing variable to the right. By this operation, we are able to extract dynamics from data and visualise the orbit of each observation. In addition, clustering of data in the stable variables is revealed. All possible paths that any observation can take in Sn are given by a subshift of finite type (SFT). We discuss mathematical properties of the transition matrix associated to this SFT. Dynamics of the population is a nonautonomous multivalued map equivalent to a nonstationary SFT. We illustrate the method using a longitudinal data of a population of households from Agincourt, South Africa.

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Lee, J. H., and Collaboration BRAHMS. "Probing Longitudinal Dynamics at RHIC." Acta Physica Hungarica A) Heavy Ion Physics 25, no. 2-4 (2006): 507–14. http://dx.doi.org/10.1556/aph.25.2006.2-4.42.

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Dattoli, G., L. Giannessi, and A. Renieri. "Storage-Ring FEL longitudinal dynamics." Optics Communications 123, no. 1-3 (1996): 353–62. http://dx.doi.org/10.1016/0030-4018(95)00445-9.

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Tremaine, Scott, and Tim de Zeeuw. "Stellar Dynamics of Needles." Symposium - International Astronomical Union 127 (1987): 493–94. http://dx.doi.org/10.1017/s0074180900185900.

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One dimensional “needles” are a limiting case of general triaxial stellar systems. Self-consistent, finite needles can have arbitrary longitudinal density distributions but have a fixed, universal distribution function. All needles are stable to all longitudinal perturbations but neutral to transverse perturbations.

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Li, Wenfei, Huiyun Li, Kun Xu, Zhejun Huang, Ke Li, and Haiping Du. "Estimation of Vehicle Dynamic Parameters Based on the Two-Stage Estimation Method." Sensors 21, no. 11 (2021): 3711. http://dx.doi.org/10.3390/s21113711.

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Vehicle dynamic parameters are of vital importance to establish feasible vehicle models which are used to provide active controls and automated driving control. However, most vehicle dynamics parameters are difficult to obtain directly. In this paper, a new method, which requires only conventional sensors, is proposed to estimate vehicle dynamic parameters. The influence of vehicle dynamic parameters on vehicle dynamics often involves coupling. To solve the problem of coupling, a two-stage estimation method, consisting of multiple-models and the Unscented Kalman Filter, is proposed in this paper. During the first stage, the longitudinal vehicle dynamics model is used. Through vehicle acceleration/deceleration, this model can be used to estimate the distance between the vehicle centroid and vehicle front, the height of vehicle centroid and tire longitudinal stiffness. The estimated parameter can be used in the second stage. During the second stage, a single-track with roll dynamics vehicle model is adopted. By making vehicle continuous steering, this vehicle model can be used to estimate tire cornering stiffness, the vehicle moment of inertia around the yaw axis and the moment of inertia around the longitudinal axis. The simulation results show that the proposed method is effective and vehicle dynamic parameters can be well estimated.

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Dai, Wei, Yongjun Pan, Chuan Min, Sheng-Peng Zhang, and Jian Zhao. "Real-Time Modeling of Vehicle’s Longitudinal-Vertical Dynamics in ADAS Applications." Actuators 11, no. 12 (2022): 378. http://dx.doi.org/10.3390/act11120378.

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The selection of an appropriate method for modeling vehicle dynamics heavily depends on the application. Due to the absence of human intervention, the demand for an accurate and real-time model of vehicle dynamics for intelligent control increases for autonomous vehicles. This paper develops a multibody vehicle model for longitudinal-vertical dynamics applicable to advanced driver assistance (ADAS) applications. The dynamic properties of the chassis, suspension, and tires are considered and modeled, which results in accurate vehicle dynamics and states. Unlike the vehicle dynamics models built into commercial software packages, such as ADAMS and CarSim, the proposed nonlinear dynamics model poses the equations of motion using a subset of relative coordinates. Therefore, the real-time simulation is conducted to improve riding performance and transportation safety. First, a vehicle system is modeled using a semi-recursive multibody dynamics formulation, and the vehicle kinematics and dynamics are accurately calculated using the system tree-topology. Second, a fork-arm removal technique based on the rod-removal technique is proposed to reduce the number of bodies, relative coordinates, and equations constrained by loop-closure. This increase the computational efficiency even further. Third, the dynamic simulations of the vehicle are performed on bumpy and sloping roads. The accuracy and efficiency of the numerical results are compared to the reference data. The comparative results demonstrate that the proposed vehicle model is effective. This efficient model can be utilized for the intelligent control of vehicle ADAS applications, such as forward collision avoidance, adaptive cruise control, and platooning.

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Fauzi, Ahmad, Saiful Amri Mazlan, and Hairi Zamzuri. "Modeling and Validation of Quarter Vehicle Traction Model." Applied Mechanics and Materials 554 (June 2014): 489–93. http://dx.doi.org/10.4028/www.scientific.net/amm.554.489.

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This manuscript provides modeling and validation of a quarter car vehicle model to study the wheel dynamics behavior in longitudinal direction. The model is consists of a longitudinal slip model subsystem, a quarter body dynamic and tire subsystems. The quarter vehicle model was then validated using an instrumented experimental vehicle based on the driver input from brake and throttle pedals. Vehicle transient handling dynamic tests known as sudden braking test was performed for the purpose of validation. Several behaviors of the vehicle dynamics were observed during braking maneuvers such as body longitudinal velocity, wheel linear velocity and tire longitudinal slip at a quarter of the vehicle. Comparisons of the experimental results and model responses with sudden braking imposed motions were made. Consequently, the trends between simulation results and experimental data were found almost similar with an acceptable level of error for the application at hand.

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Dietl, John M., and Ephrahim Garcia. "Stability in Ornithopter Longitudinal Flight Dynamics." Journal of Guidance, Control, and Dynamics 31, no. 4 (2008): 1157–63. http://dx.doi.org/10.2514/1.33561.

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MANSOUR, I., and M. KATARY. "SINGULAR PERTURBATIONS AND AIRCRAFT LONGITUDINAL DYNAMICS." International Conference on Applied Mechanics and Mechanical Engineering 2, no. 2 (1986): 193–201. http://dx.doi.org/10.21608/amme.1986.56820.

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Staszel, P. "Transverse and longitudinal dynamics at RHIC." Journal of Physics G: Nuclear and Particle Physics 35, no. 4 (2008): 044016. http://dx.doi.org/10.1088/0954-3899/35/4/044016.

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Bliss‡, Joan, Ian Morrison, and Jon Ogborn. "A longitudinal study of dynamics concepts." International Journal of Science Education 10, no. 1 (1988): 99–110. http://dx.doi.org/10.1080/0950069880100109.

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de Matteis, Guido. "Longitudinal dynamics of a towed sailplane." Journal of Guidance, Control, and Dynamics 16, no. 5 (1993): 822–29. http://dx.doi.org/10.2514/3.21088.

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Wickenheiser, Adam M., and Ephrahim Garcia. "Longitudinal Dynamics of a Perching Aircraft." Journal of Aircraft 43, no. 5 (2006): 1386–92. http://dx.doi.org/10.2514/1.20197.

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Fotakis, Jan A., Moritz Greif, Harri Niemi, Gabriel S. Denicol, and Carsten Greiner. "Longitudinal dynamics of multiple conserved charges." Nuclear Physics A 1005 (January 2021): 121899. http://dx.doi.org/10.1016/j.nuclphysa.2020.121899.

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Baek, Seung Ik, and Young Min Kim. "Longitudinal analysis of online community dynamics." Industrial Management & Data Systems 115, no. 4 (2015): 661–77. http://dx.doi.org/10.1108/imds-09-2014-0266.

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Purpose – The purpose of this paper is to explore the dynamics of an online community by examining its participants’ centrality measures: degree, closeness, and the betweenness centrality. Each centrality measure shows the different roles and positions of an individual participant within an online community. To be specific, this research examines how an individual participant’s role and position affects her/his information sharing activities within an online community over time. Additionally, it investigates the differences between two different online communities (a personal interest focussed community and a social interest focussed community), in terms of the interaction patterns of participants. Design/methodology/approach – For this research, the authors collected log files from Korean online discussion communities (café.naver.com) using a crawler program. A social network analysis was used to explore the interaction patterns of participants and calculate the centrality measures of individual participants. Time series cross-sectional analysis was used to analyze the effects of the roles and the positions on their information sharing activities in a longitudinal setting. Findings – The results of this research showed that all three centrality measures of an individual participant in previous time periods positively influenced his/her information sharing activity in the current periods. In addition, this research found that, depending on the nature of the discussion issues, the participants showed different interaction patterns. Throughout this research, the authors explored the interaction patterns of individual participants by using a network variable, the centrality, within a large online community, and found that the interaction patterns provided strong impact on their information sharing activities in the following months. Research limitations/implications – To investigate the changes of participant’s behaviors, this study simply relies on the numbers of comments received and posted without considering the contents of the comments. Future studies might need to analyze the contents of the comments exchanged between participants, as well as the social network among participants. Practical implications – Online communities have developed to take a more active role in inviting public opinions and promoting discussion about various socio-economic issues. Governments and companies need to understand the dynamics which are created by the interactions among many participants. This study offers them a framework for analyzing the dynamics of large online communities. Furthermore, it helps them to respond to online communities in the right way and in the right time. Social implications – Online communities do not merely function as a platform for the free exchange and sharing of personal information and knowledge, but also as a social network that exerts massive influence in various parts of society including politics, economy, and culture. Now online communities become playing an important role in our society. By examining communication or interaction behaviors of individual participants, this study tries to understand how the online communities are evolved over time. Originality/value – In the area of online communities, many previous studies have relied on the subjective data, like participant’s perception data, in a particular time by using survey or interview. However, this study explores the dynamics of online communities by analyzing the vast amount of data accumulated in online communities.

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Trinks, U. "Longitudinal particle dynamics in the Tritron." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 306, no. 1-2 (1991): 27–35. http://dx.doi.org/10.1016/0168-9002(91)90298-5.

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Galkina, E. G., B. A. Ivanov, and V. I. Butrim. "Longitudinal spin dynamics in nickel fluorosilicate." Low Temperature Physics 40, no. 7 (2014): 635–40. http://dx.doi.org/10.1063/1.4890989.

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Balucani, U., R. Vaia, A. Federighi, and V. Tognetti. "The dynamics of longitudinal spin fluctuations." Journal of Applied Physics 63, no. 8 (1988): 3820–22. http://dx.doi.org/10.1063/1.340624.

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Xu, Yan, Shi Yun Zhao, and Na Na Wang. "The Influences of the Load Distribution Pattern and the Position of the Locomotive on Train Longitudinal Dynamics." Applied Mechanics and Materials 496-500 (January 2014): 1063–67. http://dx.doi.org/10.4028/www.scientific.net/amm.496-500.1063.

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According to the principle of the train longitudinal dynamics, the heavy haul longitudinal dynamics nonlinear model is established to analyze the influences of the load distribution pattern and the locomotive position on train longitudinal dynamics. The study of this paper is divided into two parts. The first, train model is composed by a locomotive and six trailers, researching the influences of the load distribution pattern on train longitudinal dynamics, the analysis results show that, the best load distribution pattern is the descending from head to tail of the train, in this case, the coupler force is minimum, and the train longitudinal dynamics is best; the second, train model is composed by two locomotives and five trailers, researching the influences of the position of the locomotive on train longitudinal dynamics. The analysis results show that, if the first locomotive is at the head of the train, then the second locomotives best position is at the end of the train, in this case, the coupler is minimum. But the train longitudinal dynamics performance is the worst with two locomotives are located in the head.

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Abdullah, Muhammad, Syed Idros, Siti Fauziah Toha, and Mohamad Syazarudin Md Said. "Modelling of Vehicle Longitudinal Dynamics for Speed Control." Journal of Advanced Research in Applied Mechanics 123, no. 1 (2024): 56–74. http://dx.doi.org/10.37934/aram.123.1.5674.

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Longitudinal dynamics control is one of the essential tasks for an autonomous vehicle, where it deals with speed regulation to ensure smooth and safe operations. To design a good controller, a simple yet reliable mathematical model is needed so that it can be used as a plant and to tune the controller. Although there are many types of mathematical models available in the literature, finding the right one for control application is essential. The model cannot be too complex and can be too simple. Thus, the main objective of this work is to derive a simple yet reliable vehicle longitudinal model so that it can be used as a simulation plant in MATLAB Simulink to test or tune various types of control algorithm's performance. The model consists of three main parts which are the vehicle body dynamics, simplified power train dynamic, and braking dynamic. To validate the reliability of the model, standard urban drive cycles will be used as a reference speed and a hierarchical PID control structure with inverse plant model is used to control the pedal inputs replacing the driver in simulation environment. Results show that the controller managed to track the drive cycle with an acceptable pedal pressing response which is between 40% throttle press and 20% brake press that in line with the normal operation of a vehicle. Although only simulation result is presented, the model can be used as a good starting point for further development and testing of different types of control algorithms for future work.

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Nasir, Rizal E. M., Wahyu Kuntjoro, Wisnoe Wirachman, and Zurriati Ali. "Longitudinal Flight Dynamics of Baseline-II BWB UAV." Advanced Materials Research 433-440 (January 2012): 6636–40. http://dx.doi.org/10.4028/www.scientific.net/amr.433-440.6636.

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The objective of this paper is to investigate longitudinal flight dynamics of the said aircraft at loitering flight condition near sea level. Three mathematical dynamic models are used to compute transient response of Baseline-II E-2 BWB along with a proposed model known as Model-N. Model-N is derived to incorporate as many important derivatives, including gravitational and pitch angle factor, as possible. While all these four dynamic models are different in a sense where one model is more simple or complex than the others, the basic architecture of all these models are the same. This paper shows the short-period mode needs serious attention. A control algorithm is needed to overcome its handicap which is below Level 3 damping ratio according to MIL-F-8785C. Improvement to phugoid can be considered secondary, but one must ensure that bringing short period mode to Level 1 flying quality does not make phugiod mode response worse than it is now.

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Retnowati, Nurcahyani Dewi, Buyung Junaidin, and Engelbertus Rande. "GLIDER MODEL FLYING DYNAMICS SIMULATION EAGE-X ON LONGITUDINAL MATRA." Vortex 3, no. 1 (2022): 59. http://dx.doi.org/10.28989/vortex.v3i1.1165.

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The Glider Eagle-X aircraft is an unmanned aircraft which is expected to fly with a height of 7 meters above the ground in Yogyakarta (120 m above sea level) with a flying speed of 10 m/s. In order for the Eagle-X glider to fly stably, it is necessary to analyze the flight stability of the Eagle-X glider model. Therefore, in this study, the analysis phase of static stability and dynamic response of disturbances in the longitudinal dimension was carried out. This can be useful for students so that they can better understand the analysis of static stability and dynamic response of disturbances in the longitudinal dimension. The results of the analysis show that the flight dynamics is a value of CM-α < 0 indicating the plane is statically longitudinal and the initial response of the graph is getting smaller which indicates the plane's motion is dynamically stable. The output of the stability analysis of the flying dynamics of the Eagle-X glider model is in the form of a graph. The simulation of the flying dynamics of the Eagle-X glider in the expected longitudinal dimension is shown by the aircraft movement following the graph from the results of the stability analysis which is used as the path of the Eagle-X glider model.

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Tong, Shengxiang, Zhiwei Shi, Tao Yun, and Yizhang Dong. "Longitudinal flight dynamics modeling and a flight stability analysis of a monocopter." AIP Advances 12, no. 11 (2022): 115322. http://dx.doi.org/10.1063/5.0130626.

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A monocopter, which is a biology-inspired aircraft based on the samara, has been proved to have passive flight stability. However, due to the asymmetry of its configurations and the constant rotation during flight, its flight dynamics equation is complex. In this paper, the longitudinal stability of a monocopter is systematically analyzed. The longitudinal motion of the monocopter is used as the main research object in this paper. By transforming the body axis coordinate frame to the semi-body axis coordinate frame, its longitudinal dynamics equation is greatly simplified. Then, a fourth-order state space matrix of the longitudinal motion of the monocopter is established, and its longitudinal stability is analyzed at different pitch angles of the wing. Furthermore, the fourth-order state space matrix is simplified into a third-order matrix, and the Rouse criterion is used to analyze the stability of the simplified state space. A set of sufficient conditions is obtained as the criterion for longitudinal stability. Based on this criterion, it is found that the product of inertia [Formula: see text] is a very important factor affecting the stability. Then, the inertial parameters of the aircraft are modified, which greatly expands the range of the pitch angle that maintains longitudinal stability. Finally, the six-degree-of-freedom nonlinear flight dynamic simulation is performed to verify the rationality of the longitudinal stability criterion.

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Liu, Jinglong, Zhonghua Wu, Xiaowen Xing, and Qizhi He. "Barrier Lyapunov function and disturbance observer based omnidirectional robust gust response stabilization for multi-control-effectors aircraft." Aircraft Engineering and Aerospace Technology 92, no. 6 (2020): 777–99. http://dx.doi.org/10.1108/aeat-08-2019-0168.

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Purpose The purpose of this paper is to find an omnidirectional robust gust response stabilization (GRS) scheme with anti-disturbance and state-limited features. Design/methodology/approach Disturbance observer and barrier Lyapunov techniques, which can, respectively, estimate the lumped disturbances of the dynamic system in real-time and ensure the middle states within some prescribed ranges according to some flight safety indexes. Findings In the existing literature, almost all of the GRS controllers are either only for the longitudinal dynamics or only for the latitudinal dynamics. Few studies have considered the gust response alleviation problem with omnidirectional wind disturbance and full aircraft model. Originality/value This paper proposes a fresh scheme to deal with a more holistic GRS problem; the disturbance observer based (DOB) barrier Lyapunov backstepping longitudinal controller has been put forward; DOB nonlinear dynamic inversion to handle the multi-input-multi-output lateral dynamics; and to closely connect the two loops of the latitudinal dynamics, a manipulating variable conversion method is proposed.

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Shi, Jin, Shujing Ren, and Mengran Zhang. "MODEL-BASED ASSESSMENT OF LONGITUDINAL DYNAMIC PERFORMANCE AND ENERGY CONSUMPTION OF HEAVY HAUL TRAIN ON LONG-STEEP DOWNGRADES." Transport 34, no. 3 (2019): 250–59. http://dx.doi.org/10.3846/transport.2019.9043.

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Longitudinal dynamics performance and energy consumption of heavy haul train should be considered in the design of heavy haul railway profile of long-steep downgrades. A quantitative analytical tool is developed to assess the longitudinal dynamic performance and energy consumption of heavy haul trains with large axle loads on grades with different longitudinal profiles, including a longitudinal dynamic model of the train and a method of calculating the energy consumption during the operation of heavy haul train. The model is then preliminarily validated by the data of coupler force collected in two comprehensive tests. Finally, the proposed analytical tool is used to assess the designed longitudinal track profile of a long-deep downgrade segment of the central south heavy haul railway of Shanxi (China).

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Krishna, Visakh V., Mats Berg, and Sebastian Stichel. "Tolerable longitudinal forces for freight trains in tight S-curves using three-dimensional multi-body simulations." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 234, no. 5 (2019): 454–67. http://dx.doi.org/10.1177/0954409719841794.

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With the need for increasing length of freight trains, the longitudinal train dynamics and its influence on the running safety become a key issue. Longitudinal train dynamics is a complex issue with contributions from both the vehicle and the operating conditions such as infrastructure design, braking regimes, etc. Standards such as the UIC Code 530-2 and EN-15839 detail the procedure for on-track propelling tests that should be conducted to determine the running safety of a single wagon. Also, it only considers a single S-curve and specifies neighbouring wagons and buffers. Hence, the resulting longitudinal train dynamics would not be able to judge the effects of various heterogeneities in the train formation such as the adjacent wagons, buffer types, carbody torsional stiffnesses, curvatures, etc. Here, there is a potential of using three-dimensional multi-body simulations to develop a methodology to judge the running safety of a train with regard to its longitudinal dynamic behaviour, subjected to various heterogeneities. In this study, a tool based on three-dimensional multi-body simulations has been developed to provide longitudinal compressive force limits and tolerable longitudinal compressive force for wagon combinations passing through S-curves of varying curvatures, and the sensitivities of the various heterogeneities present in the train are assessed. The methodology is applied to open wagons of the ‘Falns’ type on tight S-curves by calculating the corresponding tolerable longitudinal compressive force, and the effect of various parameters on the same is discussed.

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Zuo, Shuguang, Duoqiang Li, Yu Mao, and Wenzhe Deng. "Longitudinal vibration analysis and suppression of electric wheel system driven by in-wheel motor considering unbalanced magnetic pull." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 233, no. 11 (2018): 2729–45. http://dx.doi.org/10.1177/0954407018806118.

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With the blowout of electric vehicles recently, the key parts of the electric vehicles driven by in-wheel motors named the electric wheel system become the core of development research. The torque ripple of the in-wheel motor mainly results in the longitudinal dynamics of the electric wheel system. The excitation sources are first analyzed through the finite element method, including the torque ripple induced by the in-wheel motor and the unbalanced magnetic pull produced by the relative motion between the stator and rotor. The accuracy of the finite element model is verified by the back electromotive force test of the in-wheel motor. Second, the longitudinal-torsional coupled dynamic model is established. The proposed model can take into account the unbalanced magnetic pull. Based on the model, the modal characteristics and the longitudinal dynamics of the electric wheel system are analyzed. The coupled dynamic model is verified by the vibration test of the electric wheel system. Two indexes, namely, the root mean square of longitudinal vibration of the stator and the signal-to-noise ratio of the tire slip rate, are proposed to evaluate the electric wheel longitudinal performance. The influence of unbalanced magnetic pull on the evaluation indexes of the longitudinal dynamics is analyzed. Finally, the influence of motor’s structural parameters on the average torque, torque ripple, and equivalent electromagnetic stiffness are analyzed through the orthogonal test. A surrogate model between the structural parameters of the in-wheel motor and the average torque, torque ripple, and equivalent electromagnetic stiffness is established based on the Bp neural network. The torque ripple and the equivalent electromagnetic stiffness are then reduced through optimizing the structural parameters of the in-wheel motor. It turns out that the proposed Bp neural network–based method is effective to suppress the longitudinal vibration of the electric wheel system.

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Kaur, Harvinder, Anil Kumar Bhalla, and Praveen Kumar. "Longitudinal growth dynamics of term symmetric and asymmetric small for gestational age infants." Anthropologischer Anzeiger 74, no. 1 (2017): 25–37. http://dx.doi.org/10.1127/anthranz/2016/0640.

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Polyakov, Vladislav A., and Nikolai M. Khachapuridze. "Magnetically levitated train’s longitudinal motion (Simulation results)." Transportation Systems and Technology 4, no. 3 (2018): 143–53. http://dx.doi.org/10.17816/transsyst201843143-153.

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Background: The no-stationary regimes of the magnetically levitated train’s (MLT) motion were the object of research. Aim: The purpose of the study is to evaluate its dynamic qualities and loading in such regimes. Methods: The work was carried out by conducting a series of experiments with a computer model of train’s dynamics. Results: The simulation results reflect its motion in the modes of acceleration, passage of the tunnel, as well as service and emergency braking. Conclusion: An analysis of these results made it possible to evaluate the dynamic properties of a train in various non-stationary motion modes and its loading in their process.

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Tianwei, Qu, Ma Weihua, Wu Dong, and Luo Shihui. "Influence of Coupler and Buffer on Dynamics Performance of Heavy Haul Locomotive." Open Mechanical Engineering Journal 9, no. 1 (2015): 1033–38. http://dx.doi.org/10.2174/1874155x01509011033.

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Aimed at the safety problem of the locomotive under the dynamic braking condition, this paper analyzes the influence of the coupler and buffer system. The coupler reposition methods of the large rotation angle coupler and the small rotation angle coupler under longitudinal coupler press force were compared. The influence of coupler and buffer system to the dynamics performance of locomotive was researched through dynamic simulation. Results show that the longitudinal coupler press force afforded by large rotation angle coupler with coupler shoulder, is larger than that of small rotation angle coupler.

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Kudryshev, Sergey B., Valentin S. Minakov, Alexey A. Zakaluyzhnyy, and Vladimir A. Peglivanyan. "Dynamics of transformation of ultrasonic vibrations in twisted waveguides." MATEC Web of Conferences 226 (2018): 04019. http://dx.doi.org/10.1051/matecconf/201822604019.

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The effective use of ultrasound energy in various technological processes largely depends on the type of ultrasonic vibrations. Wide application in practice has found longitudinal ultrasonic fluctuations in connection with simplicity of realization, and also presence of the developed theoretical and settlement base. The longitudinal-torsional ultrasonic oscillations, the realization of which practically does not differ from the realization of longitudinal oscillations, and the efficiency and technological flexibility are much higher than for longitudinal or torsional ultrasonic oscillations, practically no applications have been found. This is due to several circumstances and, above all, from the theoretical basis for the transformation of this type of oscillation, since the theory of compressedtwisted rods was developed mainly in connection with the problem of longitudinal stability. The article deals with the case of transformation of longitudinal ultrasonic oscillations into complex ones by attaching to the last stage of the concentrator of the longitudinal acoustic system of the twisted waveguide.

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Ding, Li Fen, and Ji Long Xie. "Research on the Effect of Traction Tonnage on Train Longitudinal Impact." Key Engineering Materials 450 (November 2010): 466–69. http://dx.doi.org/10.4028/www.scientific.net/kem.450.466.

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The traction tonnage has important effect on train longitudinal impact. An integrated model of train longitudinal dynamics was established based on simulation and test results. The effect of the traction tonnage on train longitudinal dynamics was investigated through modeling different types of heavy-haul trains. The model was validated by using measured longitudinal force time histories from on-track tests. Case study shows that the traction tonnage has significant influence on train longitudinal impact; Train longitudinal force increases with traction tonnage. The relationships between the maximum coupler forces (including tensile and compressive forces) and traction tonnage were obtained with the least square method for cases of train under emergency baking and release condition. The established train longitudinal dynamics model provides a platform for car body and coupler structure optimization and train control.

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Mohammed, Tariq O., Xiang Jin Wu, and Dao Chun Li. "Nonlinear Simulation of Aircraft Longitudinal Flight Dynamics." Applied Mechanics and Materials 444-445 (October 2013): 753–58. http://dx.doi.org/10.4028/www.scientific.net/amm.444-445.753.

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The purpose of this paper is to simulate flight path of Boeing-747 for longitudinal motion at selected flight conditions using 6 DoF (Degrees of freedom) nonlinear equations with MATLAB and SIMULINK. The equations are solved to compute the flight path within 100 seconds of Boeing 747 at three flight conditions, for cruise flight with different Mach numbers at same altitudes, and then Mach number at high altitude with MATLAB programming (ode45). Simulation results for different conditions are presented and analyzed.

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Driesch, Patrick, Kai Andre Horwat, Niko Maas, and Dieter Schramm. "Modeling the Longitudinal Dynamics of Terminal Tractors." ATZheavy duty worldwide 14, no. 2 (2021): 48–53. http://dx.doi.org/10.1007/s41321-021-0424-4.

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Taha, Haithem E., Muhammad R. Hajj, and Ali H. Nayfeh. "Longitudinal Flight Dynamics of Hovering MAVs/Insects." Journal of Guidance, Control, and Dynamics 37, no. 3 (2014): 970–79. http://dx.doi.org/10.2514/1.62323.

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Da Lio, Mauro, Daniele Bortoluzzi, and Gastone Pietro Rosati Papini. "Modelling longitudinal vehicle dynamics with neural networks." Vehicle System Dynamics 58, no. 11 (2019): 1675–93. http://dx.doi.org/10.1080/00423114.2019.1638947.

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Stogin, J., T. Sen, and R. S. Moore. "Longitudinal dynamics and tomography in the Tevatron." Journal of Instrumentation 7, no. 01 (2012): T01001. http://dx.doi.org/10.1088/1748-0221/7/01/t01001.

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Zdravković, S., M. V. Satarić, and S. Zeković. "Nonlinear dynamics of microtubules —A longitudinal model." EPL (Europhysics Letters) 102, no. 3 (2013): 38002. http://dx.doi.org/10.1209/0295-5075/102/38002.

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Iskrenovic-Momcilovic, Olivera. "Sliding Mode Control for Longitudinal Aircraft Dynamics." Journal of Automation, Mobile Robotics and Intelligent Systems 12, no. 3 (2018): 55–60. http://dx.doi.org/10.14313/jamris_3-2018/18.

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Berry, Donald T. "National aerospace plane longitudinal long-period dynamics." Journal of Guidance, Control, and Dynamics 14, no. 1 (1991): 205–6. http://dx.doi.org/10.2514/3.20623.

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Journal articles on the topic 'Longitudinal dynamics'

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