Smith Predictor Based Robust Rapid Tracking ControllerLIU Hongbin,HU Dejin (School of Mechanical Engineering,Shanghai Jiaotong University,Shanghai 200030,China)Precise model is hard to get in real application,a Smith predictor based robust rapid tracking controller for inaccurate model is proposed. Zero phase error feedforward controller which increases system closed-loop dynamics and disturbance observer based Smith feedback control which diminishes model hysteresis and improves stability are integrated. This method is applied in the noncircular machining with piezoelectric ceramic driver. The simulation and experiment show that the performance robustness and stability are well balanced in bandwidth about 200 Hz. The controller can decrease system hysteresis and get good tracking performance for predefined square-wave input signal.smith predictor; disturbance objection; feedforward compensation; tracking performance