A Super-twisting Controller for Active Control of Ground Vehicles with Lateral Tire-road Friction Estimation and CarSim Validation

Abstract

In this paper, a ground vehicle equipped with Active Front Steering (AFS) and Rear Torque Vectoring (RTV) is considered. The AFS, actuated through the front tires, adds an incremental steer angle on top of the driver’s input, whereas the RTV, actuated through the rear tires, imposes a yaw torque to the vehicle. These actuators allow the active control of the vehicle chassis, so that a feasible and safe reference trajectory can be tracked. To obtain such a feasible reference generation and an efficient control action, the lateral tire-road friction coefficient has to be estimated. To this aim, in this paper the lateral tire-road friction coefficient is estimated in finite-time by means of a high-order sliding mode differentiator. Then, based on this estimation, a high-order sliding mode controller is designed to track the desired references. The performance of the dynamic controller is evaluated using a CarSim virtual vehicle, and the simulation results highlight the characteristics of the proposed observer-based control.