电液耦合转向系统建模与控制方法研究

Research on Modeling and Control Strategy of Electro-hydraulic Coupling Steering System

电液耦合转向(EHCS)系统是同时具备电动助力和液压助力的新型转向系统,是提高商用车转向性能的一种方案。目前该系统工程化缺乏理论研究,为满足转向系统转向路感、转向轻便性、操纵稳定性及主动回正等性能要求,提出基于助力特性曲线设计,结合模糊PID控制的双层控制策略。完成控制器设计以后,在分析系统各部分数学模型基础上,构建了Simulink/Trucksim联合仿真模型并对结果进行仿真。结果表明:模糊PID控制下不同车速的电机实际电流跟踪性能满足要求,设计的助力特性使EHCS相较于传统转向系统具有更好的转向性能,验证了控制策略的有效性。

The Electro-Hydraulic Coupling Steering System(EHCS)is a kind of novel steering system with both electric power and hydraulic power.It is a scheme to improve the steering performance of commercial vehicles.At present,the engineering of the system is lack of theoretical research.In order to meet the performance requirements of the steering system,such as steering road feel,steering portability,handling stability and active return,a double-layer control strategy based on power assist characteristic curve design and fuzzy PID control is proposed.After completion of the controller,the co-simulation model in Simulink/Trucksim was constructed based on the analysis of the EHCS’s mathematical model.The results indicate that the actual current tracking performance of the motor at different speeds can meet the requirements under the fuzzy PID control,and the designed assist characteristic curves makes the EHCS have better steering performance than the traditional steering system,which verifies the effectiveness of the control strategy.