Model-Free Adaptive Nonlinearity and Hysteresis Compensation Control Strategy with Application to Nano-Precision Piezoelectric Stage

In the realm of nano-precision piezoelectric systems extensively applied in industrial measuring and manufacturing, addressing the inherent nonlinearities, particularly hysteresis is crucial. In this paper, a nonlinearity compensation strategy that achieves excellent tracking performance has been proposed without the need for a hysteresis model. The approach commences with the establishment of the closed-loop feedback system. Subsequently, a well-designed feedforward Zero Phase Error Tracking Control is introduced, which effectively compensates for tracking errors induced by the reference. Finally, an adaptive compensator is employed to eliminate residual errors, including hysteresis and modeling error. The proposed model-free compensation strategy demonstrates comparable performance to iterative learning control (ILC) without requiring time-consuming offline iterations while enhancing robustness against trajectory variations. The experimental results consistently validate the effectiveness and superiority of the proposed strategy for various trajectory-tracking tasks, including the adaptability to mutation trajectories. This model-free strategy can be readily applied without complex modeling or time-consuming iterations, demonstrating its potential for practical industrial applications in nano-precision motion control.