Controllability of Steer-by-Wire Steering Angle Faults at the Limits of Driving Dynamics

To ensure functional safety of vehicle dynamics controllers, monitoring functions are used to limit the effectiveness of lateral dynamic inputs to a safe, controllable level. For this purpose, driving situation dependent limits for maximum permissible lateral dynamic inputs are determined with the help of subject studies. To exploratively investigate limits of a steer-by-wire superposition function in a nonlinear driving situation, a subject study (N = 52) was conducted in a semi-dynamic driving simulator. This paper presents the study design and discusses the results obtained. A 4 × 4 within subject design including an additional baseline condition was used to investigate the independent variables steering angle fault and side slip angle. First, significant effects on the maximum lateral deviation and the integral of the side slip angle are demonstrated with a two-way ANOVA, thus proving the methodical approach. Second, limits for permissible additional steering input of a steer-by-wire system in an oversteering driving situation are determined from the obtained data.