Improved Sliding Mode Control With Time Delay Estimation for Motion Tracking of Cell Puncture Mechanism.

In this study, a cell puncture mechanism driven by a piezoelectric ceramic (PEA) is fabricated, and a novel precision robust motion controller is proposed to complete the cell puncture. A system dynamics model of the cell puncture mechanism is simplified by considering the hysteresis and disturbance as unknown terms to avoid the parameter identification of nonlinear dynamics in engineering applications. A sliding mode control (SMC) strategy with fast reaching law and proportional-integral- differential (PID)-type sliding surface, denoted as FPIDSMC, based on the simplified Bouc–Wen model is combined with time delay estimation (TDE) technology to form a novel controller, called FPID-TDE controller in this study. The stability of the controller is proven based on the Lyapunov theory. Computer simulation and semi-physical simulation experiments show the TDE technology can estimate and compensate accurately the unknown terms and does not require prior knowledge of unknown disturbance boundaries, thereby reducing controller gain. SMC can realize fast response speed, few steady-state errors, continuous output, and avoid chattering. Through a micropuncture experiment of a zebrafish embryo, the proposed FPID-TDE controller is shown to have high efficiency, high precision, and strong robustness. Therefore, the proposed FPID-TDE controller can be applied effectively to other micro nano-positioning systems driven by PEA. [ABSTRACT FROM AUTHOR]