Method for controlling PMSM (permanent magnet synchronous motor) servo system based on friction and disturbance compensation

Abstract

The invention discloses a method for controlling a PMSM (permanent magnet synchronous motor) servo system based on friction and disturbance compensation. In the method, a feedforward compensation method based on a friction model is combined with an auto disturbance rejection technology and the feedforward compensation method is complementary with the auto disturbance rejection technology mutually. In the method, a Stribeck friction model is utilized to carry out modeling on system frictions, a GA (genetic algorithm) is adopted to carry out offline identification on parameters, and an estimated value generated by an identification model carries out feedforward compensation; a state observer in the auto disturbance rejection technology observes and compensates overcompensation or undercompensation of the frictions as well as nondeterminacy and external disturbance caused by modeling errors in the system; and finally a differential tracker and a nonlinear control law are used to arrange a transient process for fixed position signals, thus solving the conflict between rapidity and overstrike and ensuring stability of the system and finite time convergence. By using the combined control, the compensation capacity of the system for the frictional nonlinearity can be improved effectively, the low-speed performance of the system is improved, and the tracking accuracy and the anti-disturbance capacity of the system are enhanced.

Description

technical field [0001] The invention relates to a control method for a permanent magnet synchronous motor (PMSM) servo system based on friction and disturbance compensation, and belongs to the technical field of high-precision servo control systems. Background technique [0002] With the improvement of the control precision requirements of the servo system, friction has become an important problem that cannot be ignored. Non-linear friction has a great influence on the dynamic and static performance of the system, mainly manifested as creeping phenomenon at low speed, waveform distortion when the speed crosses zero, large static error at steady state, and even unexpected limit cycles appear. oscillation. Another important factor that affects the accuracy of servo control system is external disturbance. Disturbances often come from uncertain factors ignored in the modeling process, sudden changes in load and parameter changes during system operation. The existence of these...

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Problems solved by technology

However, this method suppresses friction as an external disturbance, and usually does not consider the specific model of friction nonlinearity and its impact on the dynamic performance and stability of the entire system, especially the limited ability to compensate friction nonlinearity when the speed crosses zero.

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