Vehicle dynamics

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

Adaptive-Event-Trigger-Based Fuzzy Nonlinear Lateral Dynamic Control for Autonomous Electric Vehicles Under Insecure Communication Networks

Abstract: This article presents a novel adaptive-event-trigger-based fuzzy nonlinear lateral dynamic control algorithm for autonomous electric vehicles under insecure communication networks. The integration of path following control and direct yaw moment control is considered to acquire a better lateral dynamic performance. To effectively tackle inherent nonlinearities of lateral dynamics, the Takagi–Sugeno fuzzy model approach is employed to approximate the nonlinear lateral dynamics. To avoid the infeasibility of state-feedback control due to the immeasurability of sideslip angle, a fuzzy output feedback control strategy is proposed via a useful transformation. To improve resource utilization of the band-limited communication networks, an adaptive event-triggered communication mechanism is proposed to save communication resource. Moreover, to enhance the robustness of the proposed controller, the insecure communication link is considered, which is described by the Bernoulli random distributed process. Finally, simulation results show the proposed adaptive-event-trigger-based fuzzy controller not only can save communication resource, but also achieve the perfect control performance.

Active toe adjustment apparatus

Abstract: The advantage of the theoretically correct Ackerman steering of land vehicles is well documented in the literature. Steering forces, vehicle handling, and tire wear are greatly improved by having correct toe angles of all steerable wheels. Adjustements in the suspension system and steering apparatus at the factory only provide first-order corrections to toe angles. A process for actively adjusting toe angles during operation of the vehicle is disclosed in this invention. Vehicle dynamics measuring devices to sense vehicle motion or position steering devices to measure toe angles are used in this process. Secondary toe angle corrections can be actively provided to account for inherent toe angle changes during maneuvers of the vehicle. An aftermarket apparatus for actively adjusting the toe angle is an embodiment of this invention. One such device includes a mechanical screw actuator apparatus, a microstepping motor with optical encoder, computer with control strategy chip and a toe angle sensing device or an onboard dynamics computer. This apparatus can be used on all land vehicles and is especially useful for modifying existing truck and bus steering systems.

Toward More Realistic Driving Behavior Models for Autonomous Vehicles in Driving Simulators

Abstract: Autonomous vehicles are perhaps the most encountered element in a driving simulator. Their effect on the realism of the simulator is critical. For autonomous vehicles to contribute positively to the realism of the hosting driving simulator, they need to have a realistic appearance and, possibly more importantly, realistic behavior. Addressed is the problem of modeling realistic and humanlike behaviors on simulated highway systems by developing an abstract framework that captures the details of human driving at the microscopic level. This framework consists of four units that together define and specify the elements needed for a concrete humanlike driving model to be implemented within a driving simulator. These units are the perception unit, the emotions unit, the decision-making unit, and the decision-implementation unit. Realistic models of humanlike driving behavior can be built by implementing the specifications set by the driving framework. Four humanlike driving models have been implemented on the basis of the driving framework: (a) a generic normal driving model, (b) an aggressive driving model, (c) an alcoholic driving model, and (d) an elderly driving model. These driving models provide experiment designers with a powerful tool for generating complex traffic scenarios in their experiments. These behavioral models were incorporated along with three-dimensional visual models and vehicle dynamics models into one entity, which is the autonomous vehicle. Subjects perceived the autonomous vehicles with the described behavioral models as having a positive effect on the realism of the driving simulator. The erratic driving models were identified correctly by the subjects in most cases.

Hierarchical Design of Connected Cruise Control in the Presence of Information Delays and Uncertain Vehicle Dynamics

Abstract: In this paper, we investigate the design of connected cruise control that exploits wireless vehicle-to-vehicle communication to enhance vehicle mobility and safety. A hierarchical framework is used to reduce the complexity for design and analysis. A high-level controller incorporates the motion data received from multiple vehicles ahead and also considers information delays, in order to generate the desired longitudinal dynamics. At the lower level, we consider a physics-based vehicle model and design an adaptive sliding-mode controller that regulates the engine torque, so that the vehicle can track the desired dynamics in the presence of uncertainties and external perturbations. Numerical simulations are used to validate the analytical results and demonstrate the robustness of the controller.