Study On L1 Adaptive And Continuous Fast Terminal Sliding Mode Control Algorithm For Permanent Magnet Synchronous Motor

Permanent magnet synchronous motors are widely applied in high-precision engineering projects for their high reliability,high precision,high efficiency and large thrust.However,the Permanent magnet synchronous motors is a strongly coupled,multivariate,nonlinear complex system,which entails the necessity of solving problems caused by uncertainties such as nonlinear friction and external disturbance in order to meet the control requirements of high performance and high precision in a complex working environment.Based on the analysis of sliding mode control,this thesis focuses on the study of tracking accuracy,response speed,and steady-state error of the algorithm.In order to resolve the impacts of uncertain factors such as nonlinear friction and external disturbances on the PMSM control system,this study upgrades the terminal sliding mode control.First of all,a PMSM mathematical model with uncertain factors is established.The fast terminal sliding mode control is adopted to ensure the robustness of the system,and the response speed of the system is also improved.The selection of parameters fundamentally directly solves the singular problem in the fast terminal sliding mode control.Then,the exponential approach law is used to make the trajectory quickly reach the sliding mode surface,which effectively weakens the system chattering,and further improves the system robustness through the equivalent control law.The simulation under Matlab shows that: PMSM under continuous fast terminal sliding mode control possesses accurate position tracking ability and system quick response ability.A method of L1 adaptive control and ILC is proposed in this thesis in order to solve the difficulties for the PMSM high-precision motion control system to achieve ideal performance during the iterative learning control(ILC)process owing to the uncertainty of dynamic parameters.The L1 adaptive controller is used to deal with the dynamic parameter uncertainty of the system in the time domain and compensate for noise,load disturbance,etc.,and ensure that the influence of the compensated system uncertainty is small enough to facilitate the design of the ILC.According to the closed-loop stability condition of L1 adaptive control,the frequency domain method is adopted to design the ILC update law to ensure the stability of the system.The experimental results prove that this scheme possesses obvious advantages over the traditional ILC scheme,greatly improving the tracking response speed of the system while ensuring the position tracking accuracy.