Research On Active Disturbance Rejection Control Of Underwater Manipulator

The underwater robot-robotic arm platform is an important tool for completing underwater operations,realizing underwater resource development,exploration,mining,and completing various complex tasks.Because the underwater environment is complex and changeable,the ROV base will be disturbed by water flow,etc.,and the robot arm will be subject to water resistance,friction,coupling between the robot arm and ROV,etc.The above disturbances will affect the accuracy of the end effector of the robot arm.In this paper,an EKF predictive compensation algorithm is proposed for the disturbance to the base,and then an auto-disturbance control strategy is proposed for the disturbance to the manipulator joint to suppress the influence of the disturbance on the robot arm system.Position tracking control of the actuator.This paper first investigates the research and development status of underwater robot-robotic systems at home and abroad,and summarizes the current control methods and characteristics of various types of underwater robotic arms.Starting from the research background of this subject,the control method and system composition of the robot-robotic system of this subject are introduced,and the research goals of this subject are proposed.Secondly,the kinematics and dynamics of the underwater master-slave manipulator in this subject are studied.As the basis of manipulator motion control,this paper uses the DH method to establish the model between the joint coordinate systems of the underwater manipulator,obtain the conversion relationship between the end effector coordinate system and the base coordinate system,and establish the positive kinematics equation of the system The simulation verification is performed;the dynamic model of the manipulator is established by the Morsion formula and the Lagrange equation,and the joint driving torque is obtained;the mathematical model of the joint motor is established by the mechanism modeling method and the frequency sweep method.After obtaining the kinematics and dynamics model of the system,analyze the disturbance to the base,and predict the pose and position of the end effector in the disturbed state through the positive kinematics equation and Kalman prediction method.Combining the inverse of the Jacobian matrix to obtain the compensation speed of each joint.By analyzing the joint motor model and the dynamic model of the manipulator,a servo system model of the underwater manipulator was established to study the disturbances in the servo system,as well as the nonlinearity and uncertainty of the system itself.A PD feedback linearization algorithm and ADRC control technology are proposed for servo tracking control of underwater manipulators,which overcome the internal and external disturbances to the system,improve the dynamic anti-interference ability of the manipulator joints,and perform simulation verification.Finally,the effectiveness of the pedestal disturbance predictive compensation control algorithm and the robotic arm's auto-disturbance disturbance control algorithm are verified by experiments.The results show that in the case of comprehensive disturbance,a good control effect is achieved and the expected goal is achieved.