| With the unremitting pursuit of high-precision servo drive system in many high-end manufacturing fields,such as ultra-precision machining,semiconductor lithography,laser engraving and so on,more and more attention has been paid to the research of precision drive technology.However,due to the complexity of friction characteristics,how to ensure that the frictional force is accurately and efficiently compensated under the premise of fully characterizing the frictional force has become the key to the system to improve the motion accuracy.In this regard,researchers have adopted two compensation strategies based on intelligent algorithm or friction model,but so far the stability and versatility of intelligent algorithm are difficult to guarantee,and the problems of poor prediction accuracy and discontinuous prediction force of friction model have not been solved.Based on the previous work,this thesis studies the nonlinear behavior of friction in motion,and proposes a model-based compensation control strategy,which provides a reference for revealing the evolution law of friction,improving friction model and solving friction interference.A two-stage hybrid model combining Bouc-Wen hysteresis morphology and Stribeck effect is proposed.The evolution law of friction in pre-sliding stage and sliding stage is analyzed.Combined with the influence of the organizational structure of the model and the change of control parameters on the friction prediction accuracy,the outstanding advantages and disadvantages of the traditional model are clarified,it is confirmed that the new model has obvious advantages over the traditional model in terms of prediction accuracy and corner smoothness.According to the optimization principle of fruit fly Optimization Algorithm,the specific process of friction parameter identification is given,which expands the new channel of model identification.According to the motion characteristics of ball screw worktable,a P-PI control framework with integral saturation limit and selection logic operation and feedforward control and filter is designed,and the control framework is verified in dSPACE real-time control system and AEROTECH servo driven platform.Based on this,the friction feedforward compensation scheme is discussed and determined,and the compensation control framework experiment is carried out under the condition of given friction model compensation.The tracking error effect of the traditional model and the model proposed in this thesis is compared.The results show that compared with the traditional model,the model proposed in this thesis has obvious advantages in the inverse response of the system,which is of great significance to improve the motion accuracy of the system. |
