Adaptive Sliding Mode Control Of Fast Tool Servo System Based On Linear Motor

Fast Tool Servo(referred to as FTS)is a key technologies of modern ultra-precision machining processing and of the complex asymmetric surface processing particularly.With the continuous improvement of the processing requirements,problems in actual production become more and more prominent,which has attracted much attention in the field of engineering and academia.Due to the errors in design of the ultra-precision processing machine and the interference by other disturbances of the cutting force,Fast Tool Servo is not only required to improve its tracking accuracy,meanwhile,but also required to have a strong anti-interference capability.In this thesis,the related controlling strategies and simulation methods are studied for the trajectory tracking accuracy of FTS driven by permanent magnet linear synchronous motor(PMLSM).The main research work in this dissertation is outlined as follows:To start with,a large number of related literature was reviewed,through which the latest progress and development trends in Fast Tool Servo device was mastered domestically and abroad,and the main drive mode and controlling methods at present in Fast Tool Servo device were studied in depth.On this basis,the working principles for permanent magnet linear synchronous motor to drive FTS were analyzed,and the corresponding mathematical model of servo system was established.In the meantime,the main interference factors for the degradation of FTS performance driven by linear motor were discussed.Secondly,with regard to the problems in the tracking system of FTS driven by permanent magnet linear synchronous motor,in order to ensure that the system has a high tracking accuracy at the same time with a strong anti-disturbance ability,the controller of FTS system was designed by using of the controlling method of a fast terminal sliding mode.A fast terminal sliding surface was designed to improve the convergence speed of the sliding mode control,and an approach law control was adopted to reduce the chattering amplitude of the sliding mode control.On the basis of the theory,the designed controlling method and the traditional PID controlling method were simulated and analyzed by MATLAB to verify the effectiveness of the designed controlling method.Finally,in order to further improve the controlling precision and robustness of the servo system,an adaptive non-singular terminal sliding mode controller and an adaptive fuzzy terminal sliding mode controller were designed respectively.In the former one,the adaptive algorithm was used to adjust the perturbation online to reduce the chattering phenomenon of the system when the disturbance boundary is uncertain.The tracking precision of the servo system was thus improved.In the latter one,the discontinuous control volume was approximately processed by fuzzy controlling.At the same time,the adaptive algorithm was used to compensate the uncertain disturbance of the system in order to reduce the chattering to improve the tracking accuracy of the system’s controlling effect.MATLAB simulation software was used to simulate the two different controlling systems to achieve the expected controlling effect.