Enhanced Sliding Mode Control with CEMF Compensation for Tracking Control of a Piezoactuated Flexure-Based Mechanism

This paper proposes an enhanced sliding mode controller (SMC) for piezoelectric actuator based flexural mechanism (PABFM) to track desired motion trajectories. First, based on the variable structural control approach, the proposed controller is established to accommodate parameter uncertainties, nonlinearity, and unmodelled disturbances. Because the traditional sliding-mode control cannot deal with mismatched disturbances effectively, a hysteresis counterelectromotive force (CEMF) model is proposed to describe nonlinear hysteresis effect and electric-mechanical coupling of PABFM. as Similar to the CEMF voltage for a motor caused by a changing electromagnetic field due to a rotating armature, the CEMF voltage appears to PA due to polarization and molecule friction of piezomaterial. The CEMF model is identified using a charge system search (CSS). Then, the proposed SMC with CEMF compensation is studied to deal with the mismatched nonlinear disturbances. To check the consistency of the proposed SMC controller with CEMF compensation, the simulation results were compared with the experimental results. The real-time implementation validated the tracking error better than the traditional SMC.