Robust Controller Design For Linear Feeding System Based On L₂ Gain

Linear feeding system cancels all the middle transmission links from the motor to the worktable and makes the transmission links of feeding system zero."Zero-transmission" of feeding system has been obtained,which makes linear servo motor drive system apply widely in many aspects.Disturbance is the main factor which makes system servo performances decline.To improve the servo performance and obtain the fine work quality of the system,the disturbances must be attenuated.By adopting a L₂ robust controller whose structure and parameters are fixed,the control method can guarantee that the performance requirements are met when the uncertainties seriously influence on the drive system.In this paper,the L₂ gain nonlinear robust control method is applied in linear alternating current(AC) servo system and further researched.At first,based on reading many domestic and international relative literatures the improvements of linear feeding system are overviewed;the domestic and international research status of permanent magnet linear synchronous motor(PMLSM) feeding system robust control are outlined;the control schemes of PMLSM servo system are described. Secondly,based on the analyzing the basic structure and work principle of PMLSM,the vector control principle is introduced;the mathematic model of PMLSM is established;the influences of main disturbance factors of linear motor servo control system to the dynamic qualities are analyzed simply.Thirdly,basic theories of designing L₂ gain robust controller are introduced,which include passivity,stability,L₂ gain,HJI(Hamilton-Jacobi-Issacs) inequality,the back stepping method of designing storage function and robust performance designing rule of nonlinear system.Based on these theories and according to the trait of nonlinear mathematic model of PMLSM and the complex disturbance status,the L₂ gain robust control method of PMLSM servo system is researched.According to the mathematic model of PMLSM,the L₂ gain robust controller is designed,and the theory of describing L₂ gain controller is obtained by constructing properly the storage function,and then it is proved that the L₂ gain robust controller can satisfy the disturbance attenuation and asymptotic stability.At last,the simulation analysis is processed with the help of Simulink software in Matlab.The simulation results show that the L₂ gain robust controller applied in PMLSM feeding system has strong robustness and strong attenuating ability for many disturbances,and satisfies precision processing requirements.