Research on Steering Mode Switching for Autonomous Vehicles

In order to enhance the safety of autonomous driving vehicles, this work focuses on the issue of automatic-to-manual mode transition in the column electric power steering (C-EPS) system. First, we utilized an extended state observer to estimate the driver's steering torque and designed a steering mode transition unit. Second, we validated the mode switching function through an experimental platform. The results indicated that when using the extended state observer for torque estimation, the steering wheel angle and lower input angle errors were approximately ±0.5%. The input and observed torque curves were closely aligned, demonstrating excellent tracking capability of the system. In addition, by adopting a steering mode conversion unit, the switch from autonomous control to manual control has been obtained, achieving a smooth and minimal change in steering wheel angle without significant bumps. The experimental results demonstrate that the designed mode switching strategy has the advantages of speed and smoothness, and has strong practical value.