Vehicle dynamics

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

A complete fault diagnostic system for automated vehicles operating in a platoon

Abstract: A "complete" fault diagnostic system is developed for automated vehicles operating as a platoon on an automated highway system. The diagnostic system is designed to monitor the complete set of sensors and actuators used by the lateral and longitudinal controllers of the vehicle, including radar sensors, magnetometers and inter-vehicle communication systems. A fault in any of the twelve sensors and three actuators is identified without requiring any additional hardware redundancy. The diagnostic system uses parity equations and several reduced-order nonlinear observers constructed from a simplified dynamic model of the vehicle. Nonlinear observer design techniques are used to guarantee asymptotically stable convergence of estimates for the nonlinear dynamic system. Different combinations of the observer estimates and the available sensor measurements are then processed to construct a bank of residues. The paper analytically shows that a fault in any one of the sensors or actuators creates a unique subset of these residues to grow so as to enable exact identification of the faulty component. Both simulation and experimental results are presented to demonstrate the effectiveness of the fault diagnostic system in the presence of various faults.

The DARPA grand challenge - development of an autonomous vehicle

Abstract: The DARPA Grand Challenge (DGC) was an opportunity to test autonomous vehicles in a competitive situation. In addition to intelligent behaviour, the participating vehicles must also exhibit ruggedness and endurance in order to survive the fast ride over rough terrain ("win with the software- lose with the hardware"). The SciAutonics teams decided to use compact and agile vehicles that employ proven mechanical designs very suitable for the desert environment. 4-wheel drive ensures robust controllability even in slippery ground, and a roll cage protects the vehicle components from damage in case of a collision. The control system relies primarily on a differential GPS (Starfire) and a set of inertial sensors for navigating between the given set of waypoints. A sensor suite using infrared laser (LIDAR) and ultrasound sensing provides the capability of obstacle avoidance and path following. This paper shows the components of the vehicle and results from driving at the DGC.

Robust local and string stability for a decentralized car following control strategy for connected automated vehicles

Abstract: This paper presents a robust car-following control strategy under uncertainty for connected and automated vehicles (CAVs). The proposed control is designed as a decentralized linear feedback and feedforward controller with a focus on robust local and string stability under (i) time-varying uncertain vehicle dynamics and (ii) time-varying uncertain communication delay. The former uncertainty is incorporated into the general longitudinal vehicle dynamics (GLVD) equation that regulates the difference between the desired acceleration (prescribed by the control model) and the actual acceleration by compensating for nonlinear vehicle dynamics (e.g., due to aerodynamic drag force). The latter uncertainty is incorporated into acceleration information received from the vehicle immediately ahead. As a primary contribution, this study derives and proves (i) a sufficient and necessary condition for local stability and (ii) sufficient conditions for robust string stability in the frequency domain using the Laplacian transformation. Simulation experiments verify the correctness of the mathematical proofs and demonstrate that the proposed control is effective for ensuring stability against uncertainties.

Real-time weighted multi-objective model predictive controller for adaptive cruise control systems

Abstract: In this paper, a novel spacing control law is developed for vehicles with adaptive cruise control (ACC) systems to perform spacing control mode. Rather than establishing a steady-state following distance behind a newly encountered vehicle to avoid collision, the proposed spacing control law based on model predictive control (MPC) further considers fuel economy and ride comfort. Firstly, a hierarchical control architecture is utilized in which a lower controller compensates for nonlinear longitudinal vehicle dynamics and enables to track the desired acceleration. The upper controller based on the proposed spacing control law is designed to compute the desired acceleration to maintain the control objectives. Moreover, the control objectives are then formulated into the model predictive control problem using acceleration and jerk limits as constrains. Furthermore, due to the complex driving conditions during in the transitional state, the traditional model predictive control algorithm with constant weight matrix cannot meet the requirement of improvement in the fuel economy and ride comfort. Therefore, a real-time weight tuning strategy is proposed to solve time-varying multi-objective control problems, where the weight of each objective can be adjusted with respect to different operating conditions. In addition, simulation results demonstrate that the ACC system with the proposed real-time weighted MPC (RW-MPC) can provide better performance than that using constant weight MPC (CW-MPC) in terms of fuel economy and ride comfort.

Robust LPV– ∞ control for active suspensions with performance adaptation in view of global chassis control

Abstract: This paper presents a new methodology for suspension control in view of global chassis control, developed in particular to guarantee greater driving safety and comfort. The control of the suspension subsystem allows the vehicle road holding (safety) and passenger comfort to be improved, but not at the same time. In order to reach them for every driving situation, an ‘adaptive’ two-degrees-of-freedom controller for active suspensions is proposed. This control architecture is ‘open’ and could be linked and aggregated to many other controllers of vehicle dynamics. This control strategy ensures, on the one hand, the robustness in performances with respect to parameter uncertainties and, on the other hand, the trade-off between road holding and comfort. The proposed design is based on the LPV/ ∞ theory. Robust stability and performances are analysed within the μ-analysis framework.