Abstract:In order to improve trajectory prediction and tracking accuracy and robustness of fast tool servo(FTS) system, in ultraprecision machining for the components with microstructured surface, a new composite control approach was introduced. Inverse Preisach model(IPM) was used to compensate hysteresis of the piezoelectric ceramic actuator, based on which the feedforward controller was designed.The active disturbance rejection control(ADRC) law was designed for the not compensated nonlinearity, the uncertainty of the model parameters, and other unknown disturbances.A detailed derivation of the IPM was given;the linear compensation for the piezoelectric ceramic actuator was realized by IPM, using radial basis function(RBF) neural networks;then by modeling and analysis for the FTS,the equivalent model of inertia linkand twoorder oscillation link in series was obtained;a threeorder fourdimensional extended state observer(ESO) was designed.It could be used to make realtime observations to estimate and compensate for unknown disturbances from all kinds of sources.According to the characters of FTS and ultraprecision machining,the tracking differentiator was altered with speed input and acceleration input,the ADRC controller was designed.The above two controllers were combined into a composite controller. Experimental results show it can improve the predicting and tracking performance and robustness.