Improving EV lateral dynamics control using infinity norm approach with closed-form solution

Abstract

Over-actuated EVs offer a high degree of freedoms that can be exploited for better vehicle dynamic behaviour, energy efficiency, vehicle safety and comfort. If the cost of the actuators can be brought to a reasonable level, then sophisticated control algorithm should make the most out of the over-actuation property. A key aspect in lateral dynamics control of an over actuated EV with In Wheel motors and active front and/or rear steering is the so called control allocation problem. Often such problems are solved using the 2 norm (weighted least square solution) as it is expressed in a closed form-solution and has a low fixed number of arithmetic operations suited for real time control. In this work a closed-form solution based on the infinity norm for the case of 2 to 3 control allocation problem in EV lateral dynamic control is derived, and validated by means of simulation runs considering an electric vehicle with In-Wheel-Motor traction and active front and rear steering. During a “sine with a dwell” steering command at a constant velocity the superiority of the proposed algorithm based on the infinity norm is shown.