A Robust variable structure sliding mode control method for two-joint flexible manipulator

The double-joint flexible robotic arm has the characteristics of light weight, large size, low stiffness and small structural damping, so the classic PD controller can no longer meet the convergence rate requirements of the system. In order to deal with the low convergence rate in the classical PD control method for the control problem of a dual-joint flexible manipulator, a variable structure sliding mode control method is proposed based on the classical sliding mode control method. This method maintains the classical sliding surface structure when the system has not yet reached the sliding surface, and then improves the convergence rate of the system by designing the sliding mode parameters and updating and amplifying them in real time after reaching the sliding surface. The constraint relationship between control parameters and system performance indicators is given to prevent the system state from exceeding its upper bound. The proposed method is verified by Lyapunov stability theory and numerical simulation, and the results show that under the condition of reasonable setting of experimental parameters, the convergence rate of the proposed variable structure sliding mode control method is improved by 70% compared with the classical PD control method, and the control torque and angular velocity of the control system do not exceed their upper bounds throughout the whole process.