Research Of Control Strategy For Manipulator With Flexible Joints Based On Lagrange Method

The traditional rigid body model system described parts and joints as rigid body, make it not applicable in actual robot arm system with flexible joint. With the development of manipulator technology, researchers have focused on model of robot system with flexibility. To realize the modeling of robot system with flexibility, we can use some method such as accurate trajectory tracking and impedance control. The main purpose of manipulator dynamics is to describe the relationship between joint driving moment and movement. The existence of flexibility in robot joints has significant effect on manipulator dynamics.This research studied the equivalent model of robot manipulator with flexible joints. We designed the mechanical structure of four degrees manipulator and build the CAD model based on commercial software Solidworks first. Then the Lagrange energy method is used in the analysis to deduce mathematical model of four-degree of freedom flexible joint manipulator and external disturbance. The transfer function of the robot system was obtained from the analysis model. The trajectory controllers of robot system were designed with PID, backstepping method and neural network backstepping control method respectively. The performance of the controllers was verified based on the Lyapunov stability theory, simulated in MATLAB.In the same way, we propose a method for backstepping control of nonlinear systems with disturbances, which was the backstepping sliding mode control. Its stability was verified based on Lyapunov stability theory. The third using MATLAB simulated two-degree of freedom flexible joint manipulator and.the result of simulation verify the rationality of its design. The dynamic equations of Cartesian impedance of flexible joint manipulator were obtained. The dynamic backstepping control strategies were applied in the controller design, which solved "number" expansion problem comparing with traditional backstepping. The performance of the controller is verified based on the Lyapunov stability theory. Author:Xiaopin Xia (Machinery Manufacturing and Automatization) Supervised by:Hai Wang...