Research On Control Techniques Of Fast Tool Servo System Based On Maxwell Force

As a new generation of optical components, optical free-form surface is appliedmore and more widely in many fields such as aerospace and biomedical treatment.Ultra-precision machining technology is the key technology in the optical free-formsurface machining. Compared with other processing methods, Fast Tool Servo (FTS)processing could process complex structures with the sub-micron form accuracy andnanometer surface finishes. There are two major technical problems with FTS,including the design and optimization of servo motor and the effective FTS controllerbased on control algorithm. FTS systems based on Maxwell force (MFTS) couldachieve higher frequency response and greater acceleration, which is the focus in theFTS research field. To solve the trajectory tracking control problem of MFTSdevelopments, this paper studied on the control strategy and simulation method. Themain research as follows:1. The basic principle, mechanical structure and power driver of MFTS system isanalyzed and system model is established. Then the experiment platform is set up andsystem identification experiment is accomplished. By processing the test signal, themathematical model of MFTS system is confirmed, which provides the basis for theanalysis on control system.2. The input signal of MFTS is periodic and repetitive and spindle jumping canalso cause periodic disturbance signal. As these periodic signals could be decomposedinto a series of components with given frequencies based on Fourier analysis,Adaptive Feedforward Cancellation (AFC) control is applied in the controller in orderto improve tracking accuracy and anti-interference ability of MFTS.3. Because of electromagnetic inertia, there is a phase delay in the MFTS systemand it could not respond to the input signal in real-time. Based on AFC controller,Zero Phase Error Tracking Controller (ZPETC) is added. Through the inverseprocessing for the controlled system function, ZPETC could compensate the phasedelay to zero in a wide frequency range. The AFC+ZPETC controller could play theiradvantages respectively and performs very well.The simulation results show that the controller based on MFTS could track thetrajectory precisely and has a good anti-interference ability.