Extended-State-Observer-Based Sliding Mode Control for a Compliant Grinding Device With Unknown Backlash-Like Hysteresis

Passive compliance devices driven by cylinders have wide application prospects in industrial grinding areas with advantages of excellent passive adaptability and buffer capacity. However, there exists complex nonlinear hysteresis between the input pressure and the output force of cylinders. Moreover, the changes of the contact grinding force caused by various random external disturbances during the grinding process may severely reduce the grinding precision, and even cause irreversible dam-ages to the workpiece. Hence, how to keep the desired grinding force for compliance devices under the complex environment is an issue worth investigating. Focusing on the high precision grinding stage based on a compliance device driven by a double acting cylinder, the backlash-like hysteresis model is utilized to characterize the complex nonlinearities of the cylinder in this paper, and its inverse hysteresis is used to solve the desired pressure via elaborate iterative treatments. On this basis, an extended-state-observer-based nonlinear sliding mode controller is proposed. In addition, the closed-loop stability analysis is pro-vided via Lyapunov-based methods. Finally, the effectiveness and robustness of the proposed controller are verified by simulation results.