The Application Research Of Fuzzy Sliding Mode Control In Servo Drive System

High performance AC servo drive system, widely used in various areas, is demanded with the development of modern industrialization. The system should not only have the fast dynamic response and transient and steady precision, but also don't have sensitivity to the variation of parameters and disturbance. Therefore, high performance AC servo drive controller system and its products must have great potential.Sliding mode control (SMC) has for long been known for its robust in accounting for modeling imprecision and bounded disturbances.However, in SMC, the high frequency chattering phenomenon become a severe problem in practice. Fuzzy logic control (FLC) has excelled in dealing with systems that are complex, non-linear, or time-varying as it convert the linguistic control strategy of human experience or experts' knowledge into an automatic control strategy. However, the major drawback of FLC is the lack of design techniques. Merging of the FLC with SMC can form a Fuzzy Sliding Mode Controller. In this hybrid control system, the strength of the sliding mode control lies in its ability to account for modeling imprecision and external disturbances while the FLC provides better damping and reduced chattering.This paper studies an AC servo system with the Permanent Magnet Synchronous Motor (PMSM) as the executive component and focus on the design and development of fuzzy sliding mode vector control system. First, by analyzing the mathematical models of the PMSM and the vector control strategy, we find out the disadvantages of the conventional methods. Then, an adaptive sliding mode control is proposed. An adaptive algorithm is utilized to estimate the bound of uncertainty. At last, an adaptive fuzzy sliding mode control is proposed. The fuzzy inference mechanism is utilized to estimate the bound of uncertainty. And the parameters of fuzzy inference mechanism are on-line tuned through an adaptive algorithm. Therefore the control system can achieve not only robust but also optimized parameters. So a high performance AC servo drive system is achieved which has full adaptive capability.