拖拉机线控液压转向系统的联合仿真

随着农业机械的智能化、自动化程度不断提高,线控转向技术在拖拉机等农用车辆上的应用得到了重视和研究,为了指导拖拉机线控液压转向的研究,缩短开发周期。本文在分析线控液压转向系统的控制算法与结构的基础上,建立其联合仿真模型。基于AMESim软件平台建立液压系统模型,以及整车模型;利用Simulink分别建立模糊免疫PID、模糊PID、常规PID的控制器模型,通过Visual C++6.0实现接口通讯,完成了传动比为1时的转角响应、转角跟随的联合仿真,以及在拖拉机车速15 km/h,方向盘转角180°,传动比为9时的横摆角速度响应、质心侧偏角响应等联合仿真。模糊免疫PID控制可以获得0.272 s的阶跃响应时间、1.182°的跟随误差、3%的横摆角速度响应超调量、0.85°/s的质心侧偏角响应稳态值,均优于常规PID与模糊PID。联合仿真具有较强的参考价值,模糊免疫PID控制应用于线控液压转向系统可以获得理想的控制效果。

Co-simulation on hydraulic steer-by-wire system of tractor

Along with the intelligence and automation improving in agricultural machinery, the application of steering-by-wire technology in agricultural vehicles such as tractors has received concerns and researches. In order to guide the study of hydraulic steering-by-wire of tractor and to shorten the development cycle, a co-simulation model was built based on the analysis of hydraulic steering-by-wire system control algorithm and structure. The hydraulic system and full vehicle model were built on AMESim software platform. Meantime, PID, fuzzy PID and fuzzy immune PID control modeling were constructed by using Simulink software. While Visual C++ 6.0 was chosen to realize interface communication, the angle response and angle following co-simulation were completed with angle transmission ratio 1; as well as the co-simulation of yawing angular velocity response and centroid side-slip angle response under the speed of 15 km/h, the steering wheel Angle 180°, angle transmission ratio 9. The experimental results show that step response time achieves 0.272 s with fuzzy immune PID control, following error of 1.182°, 3% overshoot amount of the yawing angular velocity response, and 0.85°/s steady-state value of centroid side-slip angle response, they both prevail over the performance of common PID and fuzzy PID. In conclusion, co-simulation maintains a strong reference value, and an ideal control effect is able to achieve while fuzzy immune PID control are applied into hydraulic steering-by-wire system.