Direct Inverse Hysteresis Compensation of Piezoelectric Actuator Using Recursive Least Squares Method

Abstract

The hysteretic nonlinearity of piezoelectric actuators (PEAs) becomes one of the main factors limiting the PEA’s motion accuracy. Conventional hysteresis compensation approach consists of hysteresis modeling and inversion, and the inverse hysteresis model can be utilized to compensate the hysteretic nonlinearity. It is found that the accuracy of the inversion calculation in this ‘modeling-inversion’ approach significantly decreases in the fast motion control due to the rate-dependence of the PEA’s hysteresis. In the meantime, direct inverse modeling (DIM) was also proposed to construct the inverse hysteresis model without inversion calculation. The applicability of DIM in fast motion control can be guaranteed as no inversion calculation is necessary. However, the off-line identification still increases the complexity and difficulty for the practitioners. This paper proposes the integration of recursive least squares algorithm (RLS) and DIM so as to adjust the parameters of the inverse hysteresis model on-line with no manual intervention. As a result, the requirements on the knowledge and experience of the practitioners can be reduced, guaranteeing wide applicability. Tracking experiments of smooth and non-smooth trajectories are conducted to verify the performance of the proposed method. Trajectory tracking results show the proposed method has excellent performance across a wide frequency range.