Research On Robust Sliding Mode Control For Ring Permanent-Magnet Torque Motor Used In Compound A/C Axe

The direct drive technology has entrusted with the excellent performance for the compound A/C axis, has superiority over indirect drive which is unable to compare. The compound A/C axis that combined ring permanent magnet torque motor with the direct drive technology can complete precise, high speed and a reliable processing. Based on the project supported by National Natural Science Foundation of China "Study on Numerical Control(NC) Machine Tool Rotary Feeding Precision Direct Drive Technique and Its Control Strategy" (No.50375102), for the characteristic of compound A/C axis ring permanent magnet torque motor direct drive, and for the request of tracking performance and robust, the second order sliding mode, robust control is combined with other control methods and three control strategies are proposed to enhance servo performances of the direct drive system in this dissertation.Firstly, the compound A/C axis ring permanent magnet torque motor direct drive servo system mathematical model is established.Secondly, higher order sliding mode theory is expatiated. The reason of weakening chattering is introduced particularly. The keystone and some algorithms of second order sliding mode is introduced. The speed controller is proposed that controlled by super twisting algorithm of second order sliding mode in allusion to continues time system. The higher order sliding mode theory is introduced. The position controller is proposed that controlled by prescribed convergence law algorithm of discrete time second order sliding mode.Then, linear matrix inequality and common lemma are introduced. The method which combined robust control theory and sliding mode control theory is adopted. In sliding mode system, systems subject to matched or unmatched model uncertainties in the presence of external disturbances. A linear matrix inequality is adopted to design robust controller which is based on formula. Choosing ring permanent magnet torque motor drive directly compound A/C axis swing head, in order to complete the fundamental research of compound A/C axis ring permanent magnet torque motor direct drive servo system.Finally, Type RM166/100 ring torque motor produced by Germany CyTec Company is considered as the controlled object, its mathematical model is established, and it is necessary to simulate and analyze above three control strategies using MATLAB software. Theoretical analysis and simulation results show that the designed method enables servo system to have strong position-tracking and speed-tracking performance, and have very strong robustness against load disturbances, parameters varieties and other uncertainties, and chattering phenomenon is reduced.