基于半实物仿真的丘陵山地拖拉机电液悬挂控制试验

针对丘陵山地拖拉机电液悬挂控制系统田间试验困难、可重复性差等问题,基于半实物仿真技术开展电液悬挂控制系统试验研究。首先通过对试验拖拉机和悬挂作业装置进行受力分析,建立了丘陵山地拖拉机整机动力学模型、铧犁体的土壤阻力模型和拖拉机悬挂装置动力学模型。然后对丘陵山地拖拉机电液悬挂系统横向仿形控制、位控制、牵引力控制以及力位综合控制的系统原理进行了分析,设计了丘陵山地拖拉机电液悬挂模糊PID控制器。之后搭建拖拉机电液悬挂控制系统半实物仿真试验平台,开发电液悬挂控制系统,开展电液悬挂系统仿地形控制、力控制、位控制和力位综合控制等试验,对比分析模糊PID控制和经典PID控制方法性能。试验结果表明,模糊PID控制性能较好：在位置控制模式下,模糊PID控制无超调,控制系统响应时间为0.6s,较经典PID控制提高约33.3%;耕深控制系统稳态误差约为0.05cm,较经典PID控制降低约50%;在力控制模式下,模糊PID控制耕深的跟随误差最大值为0.38cm,标准差为0.17cm,较经典PID控制分别下降了64.5%、39.3%,验证了所开发的电液悬挂控制系统的有效性。

Experiment on Electro-hydraulic Hitch Control System for Hilly and Mountainous Tractor Based on Semi-physical Simulation

Aiming at the difficulties in the field test and poor repeatability of the electro-hydraulic hitch control system for hilly and mountainous tractors, the research on the electro-hydraulic hitch control system was carried out based on the semi-physical simulation technology. Firstly, through the force analysis of the test tractor and the suspension operation device, the dynamic model of the whole hilly and mountainous tractor, the soil resistance model of the plough body and the dynamic model of the tractor suspension device were established. The system principles of lateral profiling control, position control, force control and force-position integrated control of the electro-hydraulic suspension system for hilly and mountainous tractors were analyzed, and then a fuzzy PID controller for the electro-hydraulic suspension of hilly and mountainous tractors was designed. Afterwards the electro-hydraulic suspension control system was developed, experiments such as terrain imitation control, force control, position control and force-position integrated control of electro-hydraulic suspension system were carried out, and the performances of fuzzy PID control and classical PID control method were compared and analyzed. Finally, the test results showed that the fuzzy PID control performance was better: in the position control mode, the fuzzy PID control had no overshoot, and the control system response time was 0.6s, which was about 33.3% higher than the classical PID control; the steady-state error of the tillage control system was about 0.05cm, which was about 50% lower than that of the classical PID control; in the force control mode, the maximum value of the tillage depth following error of the fuzzy PID control was 0.38cm, and the standard deviation was 0.17cm, which were respectively 64.5% and 39.3% lower than that of the classical PID control, which verified the effectiveness of the developed electro-hydraulic suspension control system.