液压挖掘机工作装置模型及控制的试验研究

Model and experimental research on control of hydraulic excavator's manipulator

对某型液压挖掘机的工作装置进行3自由度的动力学分析,利用拉格朗日方法建立其动力学方程;并在该动力学方程的基础上给出挖掘机铲斗轨迹控制方法;介绍控制系统的软件、硬件、反馈检测装置、轨迹控制器以及为了对挖掘机进行计算机控制所进行的相关改造;给出PID控制的框图、铲斗轨迹跟踪控制表达式;对其铲斗轨迹跟踪控制进行三自由度的测试试验;由于试验挖掘机所采用的控制阀为电液比例阀,有较大的死区,为了保证控制精度,给出了死区补偿的试验方法以及PID参数设置方法和数值。研究结果表明:在所给定的PID参数下,铲斗跟踪的设定水平直线长度为2.500 m,对铲斗水平跟踪速度为136 mm/s,其精度可以控制在110 mm之内,非直线度最大为4.2%。

The dynamic analysis of the manipulator in a certain hydraulic excavator using three degrees of freedom （DOF） was carried out, and the dynamic equation of the system according to Lagrange equation was established. Trajectory tracking control law for the bucket of excavator was developed. The software, hardware, feedback measure device, trajectory controller of control system and related retrofitted work on experimental excavator were given. The three DOF test experiment on the trajectory tracking control of the excavator＇s bucket tip was carried out according to the PID control figure and trajectory tracking control equation. At the same time the method for compensating the dead band of the electro-hydraulic proportional valves and the selection of the PID parameters were put forward. The results show that at the selected parameters, the errors between the tested data and the target data are less than 110 mm on condition that the objective level line is 2. 500 m length, and the level tracking velocity of the bucket is 136 mm/s, the maximal nonlinearity is 4.2 %.