Research On Modeling And Control Algorithm Of Fast Servo Tool Holder

Fast tool servo (FTS) can be used to fabricate precision micro-structured surfaces efficiently at low costs. The key point of FTS manufacturing technology is the designing of a FTS system with high accuracy, quick response capability and good tracking performance to fulfill the manufacturing requirement. Based on the analysis of the design of the FTS system, it needs to investigate the significant factors of performance and the methods to modify the design. This thesis analyzes the key factors of the system performance in the FTS system, proposes some relevant methods to solve the problems and verifies these methods in simulation and experimental test. Such studies are as follows:(1) A theory design is proposed based on the working principle and performance requirement after the analysis of the related studies of the FTS system both here and abroad. A piezoelectric FTS model is built on the theory design and the simulation study of the model is done to apply in the designing and building of the test rig.(2) The experiment rig of the prototype FTS is constructed and the experiments are done to test and analyze the prototype rig. The experimental results show that the rig has achieved a good performance to implement the designed index. The displacement resolution is better than 4nm. The max stroke is 60.06μm, and the stroke is20.08μmat 150Hz.(3) The system model is modified based on the experimental results. After contact characteristics included in the model, the simulation results matches up to the experimental results. A phase-delay hysteresis model is proposed to describe the dynamic hysteresis characteristics. The maximum relative error of the modeling results is less than 1.5%. The hysteresis curve is linearized based on the phase-delay hysteresis model and the linear correlation coefficient of the modified results is in the above 0.9992.(4) Model feedforward and Zero-Phase-Error (ZPE) feedforward are introduced to the tracking control algorithm based on the needs of control and the PID control algorithm. The control simulation is carried out by the MATLAB(?) program. The simulation and experimental results show that the ZPE feedforward control algorithm achieves better tracking control performance.The key parameters of the fast servo toolholder on the system performance are analyzed on the theory, simulation and experiment research. Based on the phase delay characteristic, a hysteresis model and a compensation method are proposed. A control algorithm to reduce the tracking error is given based on the principle of ZPE control. It provides technical reference for the development of an engineering prototype FTS system.