Vehicle dynamics

About: Vehicle dynamics is a research topic. Over the lifetime, 12909 publications have been published within this topic receiving 204091 citations.

Influence of locomotive tractive effort on the forces between wheel and rail

Abstract: For the complex simulation of dynamic behaviour of a locomotive in connection with drive dynamics and traction control, large longitudinal creep between wheel and rail and decreasing part of creep-force function behind adhesion limit have to he modelled. This needs an adaptation of models used for the computation of tangential forces between wheel and rail in vehicle dynamics. A fast method for the calculation of wheel-rail forces developed by the author was extended to get the properties mentioned above. The simulations with a locomotive model running in a curve with varying tractive force show the influence on the wheel-rail forces distribution and on the radial steering ability. Another application example presents the investigation of a complex mechatronic system of the traction control and vehicle dynamics. A comparison with the measurements confirms that the proposed method is suitable for the investigation of problems regarding the interaction of axle drive dynamics and vehicle behaviour. For the covering abstract see ITRD E111409.

Holistic LSTM for Pedestrian Trajectory Prediction

Abstract: Accurate predictions of future pedestrian trajectory could prevent a considerable number of traffic injuries and improve pedestrian safety. It involves multiple sources of information and real-time interactions, e.g. , vehicle speed and ego-motion, pedestrian intention and historical locations. Existing methods directly apply a simple concatenation operation to combine multiple cues while their dynamics over time are less studied. In this paper, we propose a novel Long Short-Term Memory (LSTM), namely, to incorporate multiple sources of information from pedestrians and vehicles adaptively. Different from LSTM, our considers mutual interactions and explores intrinsic relations among multiple cues. First, we introduce extra memory cells to improve the transferability of LSTMs in modeling future variations. These extra memory cells include a speed cell to explicitly model vehicle speed dynamics, an intention cell to dynamically analyze pedestrian crossing intentions and a correlation cell to exploit correlations among temporal frames. These three individual cells uncover the future movement of vehicles, pedestrians and global scenes. Second, we propose a gated shifting operation to learn the movement of pedestrians. The intention of crossing the road or not would significantly affect pedestrian’s spatial locations. To this end, global scene dynamics and pedestrian intention information are leveraged to model the spatial shifts. Third, we integrate the speed variations to the output gate and dynamically reweight the output channels via the scaling of vehicle speed. The movement of the vehicle would alter the scale of the predicted pedestrian bounding box: as the vehicle gets closer to the pedestrian, the bounding box is enlarging. Our rescaling process captures the relative movement and updates the size of pedestrian bounding boxes accordingly. Experiments conducted on three pedestrian trajectory forecasting benchmarks show that our achieves state-of-the-art performance.

Periodic forcing, dynamics and control of underactuated spacecraft and underwater vehicles

Abstract: In this paper we describe spacecraft and underwater vehicle dynamics with small-amplitude, periodically time-varying forcing. The dynamic descriptions are derived so that they can be used to prescribe forcing laws for controlling the motion of these systems when they are underactuated, i.e., when the number of force inputs is less than the dimension of the configuration space. The use of periodic force inputs is motivated by the demonstrated success of using periodic velocity inputs in the associated nonholonomic kinematic spacecraft and underwater vehicle motion control problems, e.g., controlling underactuated spacecraft driven with internal rotors and underwater vehicles at low Reynolds number. By now addressing dynamic as well as kinematic response, we provide results that are useful in many practical problems in which the system cannot be modelled as purely kinematic, e.g., controlling underactuated spacecraft driven with gas jets and underwater vehicles at high Reynolds number.

Anti-lock braking control using a sliding mode like approach

Abstract: The paper starts with a brief history of the design of anti-lock brakes (ABS). The advantages of ABS are explained. For the analysis and controller design a nonlinear longitudinal car model is derived. It is shown that the dynamics can be separated conveniently into two different linear dynamics dependent on the tyre slip. The analysis of the dynamics show the highest possible braking performance. It is further shown that a continuous feedback law cannot not achieve the maximum braking performance. To achieve the maximum braking performance a sliding mode like controller design approach is suggested. The merits of this controller are shown in an example.