Research On Joint Motion Control Of Hydraulic Excavator

Excavator is a widely used construction machine.Traditional excavators require manual operation by the driver to complete the work,which consumes a lot of manpower and material resources.At the same time,the environment of the excavator work is diverse,and the excavator often needs to work in an environment which is not suitable for manual operation.This raises the need for the development of excavators to become unmanned and robotized.The effective control of the joint motion of the excavator is a key step in the robotization of the excavator.At the same time,with the development of computer technology and control theory,effective control of the joint motion of the excavator become possible.In this case,aiming at the characteristics of the excavator arm,this paper designs a fuzzy PD controller with dead zone compensation to control the joint motion of the excavator.The main work of this paper is as follows:Firstly,the working characteristics of the hydraulic excavator are analyzed,and the hydraulic mechanical arm model of the excavator is simplified into a valvecontrolled hydraulic cylinder model and modeled.Based on the multi-way valve pressure-flow equation,a non-symmetric hydraulic cylinder continuous flow equation and a hydraulic cylinder force balance equation establish a nonlinear model.The Laplace transform is used to linearize the differential equations to obtain a transfer function from the displacement of the multi-way valve spool to the elongation of the hydraulic cylinder.Second,design the PD controller,design the multi-channel dead zone compensation and use the genetic algorithm to tune the two parameters of the PD controller.The closed-loop control simulation was performed in MATLAB using the established nonlinear model and the PD controller.Thirdly,the fuzzy controller is combined with the PD controller to design a fuzzy PD controller with dead zone compensation.The nonlinear model is also used for closed-loop control simulation.The results obtained are compared with those obtained in PD simulation.In contrast,it is proved that the effect of fuzzy PD control in single-joint hydraulic cylinder motion control is better than PD control.Finally,the experimental platform was modified,and the self-made valve block and sensor were installed and the PC information acquisition software program was programmed to perform closed-loop control experiments and verify the effectiveness of the control algorithm.