拖拉机电控液压动力转向系统的研究

Electro-hydraulic power steering system for tractors

以铁牛654 l拖拉机为实验平台设计了一种电控液压动力转向系统,提出了双通道PD控制方法,利用目标转角和实际转角的偏差作为控制器输入,控制器通过判断左右转向调整PD控制参数以补偿转向油缸的不对称性对转向系统造成的影响,从而使左右转向获得相同的转向特性。台架试验结果表明:该方法很好的解决了转向油缸不对称造成的左右转向不对称问题。提高了系统的稳定性,控制精度和快速响应特性,可以作为自动或辅助驾驶车辆的转向执行机构。

An electronic hydraulic power steering system for automatically operating tractor is introduced in this paper. The control system includes steering controller and driving mechanism. A dual-channel Proportional Derivative （PD） control algoithm was devreloped for orientation tracking. The difference value between the expected angle acquired from the upper computer（that is, the computer for automatic drive control） and the actual angle of the steering wheel was used as the input parameter of the controller. By the estimation of the turning direction and the regulation of PD control parameters, the impact on the steering system from the asymmetry of the cylinder can be compensated by the controller. Therefore both steering operations can obtain the same steering quality. Experimental results show that the control algorithm can avoid the asymmetrical problems and improve the stability, control precision and quick response of the system. It can be used as the steering operator for automatic operation or assistant vehicles.