Abstract: A variable gain iterative learning control law is proposed to solve the problem that the tracking efficiency of nonlinear 3-DOF(three-Degree-Of-Freedom) manipulator's trajectory tracking control system is low in the presence of disturbance. First, the Lagrangian method is used to establish the kinetic equation. Then, the variable gain iterative learning controller with three degrees of freedom manipulator structure is designed and its convergence is analyzed. Finally, through Matlab Simulink simulation module, the three-degree-of-freedom manipulator control system simulation diagram is constructed, and the comparative simulation test of closed-loop fixed constant and closed-loop variable gain PD(Proportion Differentiation) iterative learning control is carried out. Simulation results show that the three-degree-of-freedom manipulator based on variable gain iterative learning can converge to the desired trajectory in a short time in the presence of interference.

Key words: variable gain iterative learning, Lagrangian method, Simulink simulation