There is growing interest in steer-by-wire (SBW) systems because they provide significant benefits to classical vehicles, and are indispensable to autonomous vehicles. However, an emergency backup strategy is needed to steer a vehicle to safety if its SBW actuators fail completely. Differential drive assisted steering (DDAS), which uses torque vectoring to steer a vehicle, has been proposed as a backup strategy for SBW systems. However, vehicle stability control (VSC) — a required feature in most modern vehicles — also relies on torque vectoring. This paper demonstrates, for the first time, through simulations, that conflicts may arise between VSC and DDAS, rendering DDAS ineffective as a SBW system backup strategy. This preliminary study motivates the need to pay attention to, and develop strategies for addressing these conflicts. As an example, the addition of speed control to DDAS is shown as a potential strategy for mitigating these conflicts.
