Hysteresis observer enhanced integral terminal sliding mode control of piezoelectric platform for precision tracking applications

The nonlinearity of piezo-actuated positioning platforms significantly impacts their performance in high-precision applications. In this work a dynamic model of piezoelectric platform was developed firstly with the asymmetric Bouc-Wen model. Next, a terminal sliding mode observer with the super-twisting mechanism was designed to accurately estimate the state of the system. Then, a novel control strategy named Hysteresis Observer Enhanced Integral Terminal Sliding Mode Controller (HO-ITSMC) was proposed to achieve precise displacement tracking. Its stability is theoretically proved by the Lyapunov theorem. A key feature of this controller lies in its ability to drive the state of the system into zero in finite time, regardless of the initial state. Extensive experiments have thoroughly validated the effectiveness of the proposed control method, demonstrating its superior precision-tracking performance compared to traditional controllers.