The adaptive control system design with a model-free external loop as a compensator

In order to overcome the bad performance and deficiencies of the adaptive control (AC) system dealing with the controlled plant with some unmodeled dynamics, we proposed a new control method called modularized method. It consists of two feedback loops. One is the traditional adaptive feedback loop, called inner loop. The other is called model-free-adaptive-control (MFAC) based external loop, which is used to serve as a compensator for system tracking error caused by time-varying parameters, parameter estimation error, model mismatch and unmodeled dynamics. This new method has very simple configuration, and can depress the system tracking error caused by the factors mentioned above. Simulation results have demonstrated the efficiency of the proposed method.