| Autonomous Underwater Vehicle-Manipulator System is an important platform of underwater operation.In the observation mission,the base disturbance have a big impact on the manipulator end pose control accuracy.In this paper,based on the kinematics and dynamics analysis of the underwater manipulator,hierarchical control is proposed for strong and weak disturbance of AUV,and an optimal compensation algorithm for three joints of manipulator is proposed for weak disturbance.The feedback linearization controller is designed for the manipulator joints,and the hydrodynamic,joint friction and AUV coupling dynamic compensation terms are combined.Finally,the visual simulation of the disturbance compensation algorithm and the verification of the pool test are completed.Firstly,this paper investigates the research status of underwater manipulator and sumrmarizes the characteristics of various manipulator control algorithms.Then the research objectives and the effectiveness index of manipulator terminal pose control are proposed,which provide the effectiveness criteria for the simulation and test afterwards.Secondly,the paper analyzes the kinematics and dynamics of underwater manipulator.In this paper,the standard D-H method is used to establish the coordinate system of the links of the three-function underwater manipulator.Finally,the transformation relation between the target coordinate system,the manipulator end coordinate system and the AUV carrier coordinate system are obtained,and the pose of the underwater manipulator and AUV under the optimal working mode is deduced.And Lagrange dynamics equations of underwater manipulator is adopted to establish the basic dynamic equations,and AUV coupling dynamic influence term is analyzed.Then the integrated underwater manipulator dynamic equation is obtained.Then,the classification of AUV disturbance is discussed,and the hierarchical control strategy is proposed according to the strong and weak disturbance criteria.The analysis is mainly aimed at the bow disturbance,lateral drift disturbance and depth disturbance of AUV,and the optimization cormpensation algorithm is designed to compensate the original expected input of the shoulder joint and arm joints.Then,aiming at the nonlinear term in the dynamic equation of the underwater manipulator,the feedback linearization control algorithm of the manipulator joint was designed,and the friction compensation module of the hydrodynamic joint was built.After that,the simulation visualization platform was built by Matlab Simulink Simmechanic module for simulation.The simulation results showed that the disturbance compensation algorithm met the validity criterion of pose accuracy.Finally,the pool experiment is prepared.Using Matlab Simulink XPC real-time control module,computer PC as a PC,uses industrial computer and data acquisition board to complete the control instruction issuing and feedback signal acquisition.Design two scenarios including faster and slower movement of manipulator under the comprehensive disturbance to explore the control effect of algorithm.The experimental results show that the disturbance compensation algorithm proposed in this paper has a good control effect,and its position and attitude mean square error meet the criterion of effective observation range,which proves that the algorithm has a good control accuracy under the combined disturbance of base heading and depth. |
