Enhanced Discrete-Time Modeling via Variational Integrators and Digital Controller Design for Ground Vehicles

In this paper, a discrete-time controller for ground vehicles is proposed, for the tracking of desired references for lateral and yaw velocities. A novel discrete-time model of the vehicle dynamics is considered, which is obtained by means of a variational integrator known as symplectic Euler. The control inputs are given by active front steering and rear torque vectoring. Simulations have been carried out considering a virtual automobile implemented in CarSim, and a comparative study has been performed considering alternative discrete-time controllers, based on a sampled continuous-time controller and on a discrete-time vehicle model obtained by means of the explicit Euler method. The controller performance has been analyzed considering various sampling periods, showing a robustness property when the sampling period increases. Moreover, the robustness of the proposed discrete-time controller performance has been tested to show its robustness versus parameter variations.