Research On Electro-hydraulic Servo Control Strategy For Trajectory Tracking Of Robotic Excavator

Compared with the traditional hydraulic excavator,robotic excavator is a comprehensive and multiple field high-tech,which can not only save human cost,improve work efficiency,but also complete the work with higher quality.The electrical and hydraulic servo control strategy of robotic excavator is the core of automatic digging.This paper mainly studies the electrical and hydraulic servo control strategy of robotic excavator.For this reason,the kinematics analysis of the working device and the mathematical modeling of the hydraulic system of robotic excavator are carried out,the single hydraulic cylinder tracking error controller based on the sliding mode variable structure and the multiple hydraulic cylinder synchronous error controller based on PID are designed,and the anti flow saturation controller based on load prediction is designed.A joint simulation experiment based on AMESim and Simulink is carried out,and a test-bed of robotic excavator is built,and the experimental research on the tracking control of straight-line motion and irregular motion of robotic excavator is completed.This paper mainly studies the following aspects:1.The kinematics of the working device of robotic excavator is analyzed,and the conversion method between the joint space variables and driving space variables of the working device are proposed.This paper analyzes the characteristics of the hydraulic components of robotic excavator’s hydraulic system,and establishes the mathematical model of the hydraulic system.2.The overall design of the servo control system for the trajectory tracking of robotic excavator is carried out,including the design of the tracking error controller based on sliding mode variable structure and the design of multiple hydraulic cylinder synchronous error controller based on the PID control method,which effectively suppress the influence of the single joint motion error on the multiple joint final composite motion.And the anti flow saturation control strategy is designed to solve the problem of flow saturation effectively.3.A joint simulation model based on AMESim and Simulink is built for robotic excavator,and the track tracking simulation experiments are carried out for the synchronous controller of robotic excavator and the anti flow saturation controller when the flow saturation phenomenon occurs.The results show that the synchronous controller and anti flow saturation controller can improve robotic excavator control accuracy of human trajectory tracking.4.The experimental platform of robotic excavator is designed.The experimental platform of robotic excavator is built based on the small excavator.The tracking experiment of the straight-line trajectory of robotic excavator is carried out.The validity and feasibility of the designed electrical and hydraulic servo controller are verified.