Active disturbance rejection-sliding mode combined control of flexible manipulator based on improved ESO

Abstract

In order to improve the control precision and anti-disturbance performance of the flexible manipulator, a combined control method based on improved active disturbance rejection control and sliding mode control was proposed. Firstly, the dynamic model was constructed by the Lagrange method and assumed mode method, and then the flexible arm was decoupled by singular perturbation theory to obtain the slow-varying and fast-varying subsystems. For the slow-varying subsystem, the improved active disturbance rejection control was used to achieve trajectory tracking, and a new fal function was constructed to solve the problems that the inflection point of the fal function was not smooth, which easily caused the system chattering and the system gain was large when the error was large. At the same time, sliding mode control was used to replace the nonlinear state error feedback control, a new reaching law was adopted in order to improve the control quality of sliding mode control. For fast-varying subsystem, sliding mode control was used for vibration suppression. The Matlab simulation results show that the combined control method has better trajectory tracking performance, anti-disturbance performance and vibration suppression performance than the traditional active disturbance rejection control.

Keywords

• flexible manipulator
• singular perturbation
• extended state observer
• auto disturbance rejection control
• sliding mode control