Analytical Solution And Control Algorithm Of Seven-DOF Manipulator

Robotics and the robot industry have become important pillars of future socio-economic development The seven-degree-of-freedom(7-DOF)manipulator is an important direction for the future development of robots due to its flexibility,light weight,and diverse applica-tions.This thesis takes the 7-DOF manipulator with spherical wrist structure as an example,and studies the kinematics analytical solution,dynamics analytical solution and control the-ory of the 7-DOF robotic arm and verifies the accuracy and feasibility of these algorithms through simulation.The main contents of the research are:(1)The configuration of the robotic arm was classified and compared in this thesis,and the 7-DOF manipulator configuration with a spherical wrist joint was selected as the research object.D-H coordinate system is established,and the arm-angle is parameterized using the characteristics of the D-H coordinate system and the geometric characteristics of the manip-ulator,so as to realize the kinematic analytical solution of the manipulator.Considering the application of the algorithm,the accuracy of the algorithm was studied,and the formula for determining the accuracy was proposed to avoid the sudden change of motion.The MATLAB robotics toolbox and ROS were used to establish the robotic arm model for its visualization,the consistency of the preset target and the calculation result verifies the accu-racy of the forward and inverse kinematics algorithm.From the working conditions of the joints of the robot arm in a complete trajectory,the smoothness of the trajectory curve proves the continuity of motion.The numerical solution method in is compared with statistical re-sults,and the superiority of the algorithm is verified through faster calculation speed and more stable calculation results.(2)With screw theory and kinematics,from the analysis of the characteristics of the spherical wrist configuration,the Jacobian matrix of the 7-DOF manipulator composed of screws is derived,including the overall Jacobian matrix of the 7-DOF manipulator and the Jacobian matrix of the object with each joint as the reference system.On this basis,the inertial matrix of each joint of the manipulator is established to obtain the kinetic energy of the manipulator and combine it with kinematics,the algorithm finds the potential energy.In this way,La-grange dynamic equations are constructed.Through the application of screw to combine coordinates,matrix and motion,it solves the problem that the structure of the 7-DOF ma-nipulator is so complex and it is difficult to establish and solve dynamic equations.Subse-quently,numerical simulation is carried out through the dynamic numerical calculation mod-ule of MATLAB,and the correctness of the analytical solution of dynamics is proved by comparing the simulation results with the theoretical results.(3)Combining the model of kinematics and dynamics,this thesis uses MATLAB/simulink platform for simulation control research.Using the characteristics of force control space and position control space being orthogonal and non-interfering with each other,the kinematics algorithm is used for position control in the S-Function custom module,and the dynamics algorithm is used for torque control.The control law is the PD control law.In order to deter-mine the value of the PD control parameters,it is derived from the dynamic parameters of the robotic arm to preliminarily determine the value range of the PD control parameters;Then the MATLAB genetic algorithm toolbox is applied,and the adjustment time of the control system is used as the objective function to optimize the PD control parameters.The control algorithm is optimized through the error control of each joint during the motion of the 7-DOF manipulator system.