Research On Motion Control Strategy Of Hydraulic Excavator Working Device

As a common construction machinery,hydraulic excavators p lay an extremely imp ortant role in construction engineering,municip al engineering,water conservancy construction and mineral mining.The vast majority of hydraulic excavators we have seen require manual op eration,which not only increases the inp ut of labor costs,but also endangers the life of driver s in some sp ecial workplaces that are not suitable for p ersonnel to enter.Therefore,it is very urgent to study the intelligent,autonomous and unmanned hydraulic excavators.Among them,the research on the joint motion control of the hydraulic excavator working device is the basis for the unmanned develop ment of the hydraulic excavator in the future.Taking the joint motion control strategy of the hydraulic excavator working device as the main research content.Firstly,the forward and inverse kinematics analysis of the hydraulic excavator working device is carried out by introducing the D-H coordinate method in robotics,and the tooth tip position of the excavator bucket is obtained.The mutual conversion relationship between the posture coordinates,the joint angle of the working device and the expansion and contraction of the working cylinder,then the cubic spline interpolation method is used to plan the spatial excavation path of the excavator working device,and then the piecewise polynomial planning method is used to plan the excavation of the excavator.trajectory planning.Secondly,by analyzing the working principle of the electro-hydraulic proportional control system of the hydraulic excavator,the working device model of the hydraulic excavator can be simplified to a hydraulic cylinder model controlled by a multi-way valve.Then,the transfer function of the electrohydraulic proportional control system of the excavator working device is established through the force balance equation of the hydraulic cylinder of the working device,the flow continuity equation and the pressure-flow equation of the multi-way valve.Thirdly,the working principle of the genetic algorithm and firefly algorithm to set the proportional integral differential(PID)controller parameters is introduced in detail,and then the PID motion controller of the hydraulic excavator working device based on the Genetic Firefly Algorithm(GFA)is designed,and then carry out a simulation comparative analysis in MATLAB/Simulink,which further verifies that the genetic firefly algorithm to tune the PID control parameters has a more superior control effect.Finally,it is proposed to introduce the sliding mode variable structure control method into the joint motion control of the excavator working device to enhance the robustness of the control system;The radial basis function(RBF)neural network is used to approximate the nonlinear factors in the system.Aiming at the problem of chattering in the traditional sliding mode variable structure control,an improved sliding mode switching control term is used to suppress the chattering phenomenon;In order to improve the pressure response in the hydraulic control system of the working device,also considers the influence of the nonlinear characteristics of the dead zone of the multi-way valve in the hydraulic system of the working device on the control effect,and then designs a multi-way valve dead zone compensated neural network sliding mode controller,and the simulation comparative analysis is carried out through the Solid Works and MATLAB/Simulink co-simulation platform.The simulation results show that the control strategy proposed in this paper is more robust than the GFA-PID control and sliding mode variable structure control on the joint motion of the hydraulic excavator working device,and the pressure response in the hydraulic system of the working device is better.The tracking control error of the desired motion trajectory of the working device joint is smaller,which verifies the effectiveness and superiority of the neural network sliding mode control strategy with multiway valve dead zone compensation proposed.