Toward integrated motion planning and control using potential fields and torque-based steering actuation for autonomous driving

This paper proposes an integrated motion planning and control approach for autonomous car navigation. Existing approaches to autonomous vehicle navigation typically plan a trajectory and pass it on to a steering controller that commands steering wheel angle (SWA) or curvature at every timestep to minimize tracking error. However, this approach exhibits large amounts of control effort, and ignores other criteria such as smoothness or the importance of staying on plan at different times. Conversely, our proposed approach leverages the concept of potential fields to represent a driving corridor with a desired tracking error tolerance and direct torque-based steering control to smoothly steer the vehicle with a much smaller control effort. Further, using potential fields allows us to naturally incorporate obstacles in the driving corridor to circumvent them, with typically no need for explicit trajectory planning. We compare our approach to a standard steering controller in experiments with a real-world autonomous vehicle platform. Results show that our proposed approach achieves similar path tracking performance as a high-gain SWA controller, but with much less actuator effort.