Terminal Second Order Sliding Mode Control Of Permanent Magnet Linear Synchronous Motor

Taking the permanent magnet linear synchronous direct drive servo system motor asthe control object and according to the operation of system which is vulnerable to theuncertain factors, such as parameter variations, load disturbances, end effect and frictiondisturbance characteristics, in order to improve the robustness and fast performance of thesystem, basing on the theory of sliding mode control, the second order terminal slidingmode control of permanent magnet linear synchronous motor has been studied as follows:Firstly, the structure and operating principle of permanent magnet linear synchronousmotor servo system have been summarized, and then the mathematical model of permanentmagnet linear synchronous motor was established. According to the characteristics of thesystem, the uncertain factors for permanent magnet linear synchronous servo system havebeen analyzed.Secondly, basing on the introduction of higher order sliding mode and the terminalsliding mode control theory, the second-order non-singular fast terminal sliding modecontrol methods has been selected. And then the nonsingular fast terminal sliding variableshas been designed to solve the problem of the terminal sliding singularity. Meanwhile, thesystem global convergence speed was improved when the state of the system closed to theequilibrium point. Using the super coiled second order sliding mode control algorithm, thechattering of the system was weakened. The simulation results showed that thesecond-order non-singular fast terminal sliding mode control not only improved theresponse speed of the system, made the system present good robustness, but also weakenthe system chattering. Finally, the system showed a good positioning accuracy.Finally, the combination of the direct adaptive control algorithms and the super twistingsecond order sliding mode control achieved the gain’s online adaptive of the super twistingalgorithm. And then overcame the limitation that the adjustments of the gain of the supertwisting control algorithm which needs to know the boundaries. The terminal slidingsingularity problem has been solved by the design of the nonsingular terminal sliding modevariable. The simulation results showed that the adaptive second-order nonsingular terminalsliding mode controller for permanent magnet linear synchronous servo system improved the ability of the system to weaken the chattering, had a very good positioning capabilityand robustness when the system suffered the self-changing of the parameters, disturbance ofthe load, the friction disturbance.