Applications of Force Feedback Steering for Steer-by-wire Vehicles with Active Steering
The question of what kind of torque to create on a FFB steering system for a steer-by-wire vehicle is a broad one. As a first step, since steer-by-wire vehicles have no inherent steering feel like conventional steering vehicles, creating an artificial steering feel is important. This allows a steer-by-wire vehicle to `feel' like a conventional steering vehicle and gives the driver the same kinds of information that he is used to getting from those vehicles. Once a realistic and stable artificial steering feel can be created on steer-by-wire vehicles to mimic conventional steering vehicles, the question of active steering can be addressed. Conventional steering systems reflect the actual moments acting on the roadwheels in their steering feel. However, during an active steering intervention, the handwheel and roadwheels are no longer in sync, begging the question of what moments should be reflected in the steering feel then. This dissertation shows that using the concept of a virtual wheel to feed back the driver's intended tire moments, rather than the actual tire moments, results in a supportive steering feel. Therefore, using the techniques presented in this dissertation, a steering feel that supports scenarios with and without active steering can be implemented on steer-by-wire vehicles. The last major contribution of this work builds on the artificial steering feel created by overlaying this supportive steering feel with predictive haptic cues to aid in the obstacle avoidance task.