Design of Fault-Tolerant Control for Trajectory Tracking

International audienceThe paper proposes a fault-tolerant integrated control system with the brake and the steering for developing a driver assistance system. The purpose is to design a fault-tolerant control which is able to guarantee the trajectory tracking and lateral stability of the vehicle against actuator fault scenarios. Since both actuators affect the lateral dynamics of the vehicle, in the control design a balance and priority between them must be achieved. The method is extended with a fault-tolerant feature based on a robust LPV method, into which the detected fault information are incorporated. The control design is performed by using the Matlab/Simulink software and the verification of the designed controller is performed by using the CarSim software

Robust LPV - Hinf Control for Active Suspensions with Performance Adaptation in view of Global Chassis Control

International audienceThis 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 to improve the vehicle road holding (safety) and passenger comfort but not at the same time. In order to reach them for every driving situation, an “adaptive” two degree 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 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/Hinf theory. Robust stability and performances are analyzed within the μ- analysis framework

A LPV suspension control with performance adaptation to roll behavior, integrated in a global vehicle dynamics control strategy

International audienceThis paper is concerned with an integrated vehicle dynamic control using different kind of actuators. The new and very interesting trends in vehicle dynamic control are to synthesize multivariable controllers using LPV/H∞ framework, see [1]. A new strategy for global chassis control is proposed using a smart coordination between the front/rear active steering actuators and four active suspension ones in order to improve vehicle handling and ride performances. This control is achieved in the LPV/H∞ robust control framework, which allows activating appropriately the steering controllers and performs suitable combination with the suspension control depending on some varying parameters. First the use of front and rear steering actuators is of great interest to control the yaw rate, and to maintain a low side-slip angle in order to keep the vehicle stability (without using the braking systems that would reduce the vehicle speed). On the other hand the suspension control is adapted simultaneously (for each of the four active dampers) in order to ensure the passenger comfort in normal situations and, in the case of critical driving situations, to improve the road handling performances. In particular the objectives will be to mitigate the influence of the road profile (stochastic), to reduce the effects of load transfers, and to minimize the roll angle. A specific stability monitor based on the vehicle side-slip measurement provides the scheduling parameter which enables the active steering control when a dangerous situation appears. This new kind of scheduling strategy permits smooth control actions between the suspension and steering systems. The interesting side effect concerns the prevention of the car skidding behavior that would appear using active braking systems (due to possible high braking torques). Simulations on a full non-linear vehicle model, subject to dangerous driving situation, reveals the satisfactory improvements on the vehicle handling performance, stability and robustness of the proposed LPV/H∞ control strategy