Compensate controller design for solving the parameter drift problem of learning fuzzy control systems

In order to solve the parameter drift problem of learning fuzzy control systems, a compensate controller is proposed based on the H-infinite control theory. The proposed compensate controller has the H-infinite tracking capability and thus is named as the H-infinite tracking compensator (HTC). The characteristic of the HTC design is that the concept of Lyapunov energy convergence is employed to solve the H-infinite controller design problem. Besides, for a leaning fuzzy control system, the HTC ensures the tracking error of the learning fuzzy control system is bounded. Therefore, the dead-zone modification can be used to stabilize the final learning stage of the adaptive fuzzy control system. In other words, the parameter drift problem of a learning fuzzy control system can be resolved by the use of dead-zone modification with HTC so that the stability problem does not appear.