Abstract: In order to improve the comfort and safety of commercial vehicles, and enhance the intelligent level of commercial vehicles. For heavy commercial vehicles, an Intelligent Electro-Hydraulic steering system with conventional power assisted mode, torque superposition mode and automatic steering mode is developed based on hydraulic power assisted recirculating ball steering gear and motor, and the decision-making method of man-machine cooperative control for steering system is designed. In order to verify the function and performance of the designed intelligent electro-hydraulic steering system, the steering angle step response test and nozzle function test are carried out. The results indicate that, the step response time of steering angle is less than 23 ms, the steady-state error is less than 0.8 ° and the rise time meets the requirements of steering system, the steering system can switch from the automatic steering mode to the manual intervention mode according to the test requirements. The developed intelligent electro-hydraulic steering system has good performance, which lays a foundation for the intelligent driving of commercial vehicles.

Key words: Commercial vehicle; Intelligent electro hydraulic steering system; Decision-making method of manmachine cooperative control

摘要： 为提高商用车的舒适性和安全性，提升商用车的智能化水平，针对重型商用车，以液压助力式循环球转向 器和电机为基础，开发了具有常规助力模式、力矩叠加模式、自动转向模式的智能电液转向系统，设计了转向系统 人机协同控制决策方法。为验证所设计的智能电液转向系统的功能及性能，进行了转向角阶跃响应试验和接管功能 试验。试验结果表明，转向角阶跃响应时间小于 23 ms，稳态误差小于 0.8°，上升时间满足转向系统要求；转向 系统能按试验要求由自动转向模式切换至人工介入助力模式。所开发的智能电液转向系统具有良好的性能，为商用 车的智能化驾驶打下了基础。

关键词: 商用车；智能电液转向系统；人机协同控制决策