Linear active disturbance rejection control of servo systems via IMC principle with active damping and sliding mode techniques

In this paper, a new linear active disturbance rejection control (LADRC) is proposed for servo systems based on active damping (AD), internal model control (IMC) and sliding mode control (SMC). The IMC rules are applied to tune the controller gains for a prescribed tracking performance. The AD method injects a virtual damping force into the motion system to actively attenuate disturbances. By deriving the sliding dynamics of IMC, a boundary layer solution of SMC is employed to enhance the robustness of control system. As the improved robust IMC scheme is applied as the controller of LADRC, the uncompensated disturbance of linear extended state observer can be better suppressed. With this method, a higher tracking control accuracy is expected to be obtained in the presence of uncertain dynamics. Theoretical stability was analyzed based on the Lyapunov method. Comparative experiments were conducted on a permanent magnet synchronous motor to validate the superiority of the proposed approach.