CLC number: U463.6

Research on Steering Mode Switching for Autonomous Vehicles

基于自动驾驶车辆的转向模式切换研究

¹ School of Electronics and Control Engineering, Chang'an University, Xi'an 710064, Shaanxi, China
² Chang'an Dublin International College of Transportation, Chang'an University, Xi'an 710064, Shaanxi, China
³ State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031, Sichuan, China
⁴ Shaanxi Zhuoxin Engineering Testing Co., Ltd, Xi'an 710000, Shaanxi, China

Received: 28 August 2024

Abstract

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.

摘要

为了提高自动驾驶车辆的安全性，以管柱式电动助力转向系统(Column Electric Power Steering，C-EPS)为研究对象，研究了车辆转向系统自动向人工模式的切换问题。首先利用扩张观测器预估驾驶员手力矩，设计转向模式过渡单元，然后通过实验台进行了模式切换功能验证。结果表明：扩张状态观测器进行手力矩估算时，转向盘角度和下端输入角度误差约为±0.5%，输入手力矩和观测手力矩曲线基本重合，系统具有良好的跟踪能力；采用转向模式过渡单元后，当驾驶员介入时，与驾驶控制权直接切换的方式相比，转向盘的角度变化率较小，无明显顿挫感，验证了设计的模式切换策略具有良好的快速性和平滑性，具有较强的实用价值。