Steering actuator sizing of prototype electric one-seater

Abstract

This work describes the setting of power requirements of the steering actuator for an electric demonstration vehicle (EDV). The EDV is a small one-seater vehicle with mass of approximately ~ 400 kg and is equipped with a steer-by-wire system. The dimensioning of steering systems components other than the steering actuator is not discussed in this report. An analytic method has been developed to estimate maximum expected steering torque in creep and high speed scenarios. Furthermore, the model allows the prediction of suspension geometry influence on steering torque amplitude. The steering effort is analyzed by means of maximum expected tire forces, which are estimated by a simple physical tire model. In the tire model maximum tire-to-ground friction is estimated for various driving scenarios considering the physical limits of the tires. This approach allows the analysis to be performed independent of vehicle motion and without a detailed dynamic car model. The general design of the steer-by-wire system and a steering control setup is presented in order to evaluate the proposed steering system with respect to control time and precision. This is accomplished for a given actuator setup. As major outcome of this work the overall power requirements - such as torque, speed, power and energy demand - of the steering actuator are presented.