| Auto disturbance rejection control (ADRC) theory has been generated recently as the outcome of the conflict between control theory and control engineering. ADRC theory is being developed rapidly and its superiority will be demonstrated in many domains. Strong robustness and good applicability are the controller's advantages, but there are still some faults in ADRC controller. For instances, the frequency characteristic, stability can not be achievedtheoretically. The greatest obstacle of the applications in the industry projects is that many parameters in ADRC are very difficult to be adjusted. In this thesis, the main work is on the parameter tuning. Firstly, a general introduction of the ADRC about the originalty, the development recently and basic structure were given. Also it points out the ADRC controller advantages over classical PID controllers.As a special slidding control method, variable structure controller compels the states of the controlled system to zero in terms of the designed tracks. Based on this character, the principle of the variable structure control is introduced to design ADRC, which not only gives the theoretical analysis in the parameter tuning but proves the stability of the extended states observer and the nonlinear states error feed-back in the ADRC. At the same time, because the main function of the transient process is to weaken the setting value leaping a tracking differentiator is designed for a typical two order system so as to lessen the parameters.The notion of time scale is integrated with parameter tuning. A conclusion obtained is that series of parameters for one controlled system can adapt to other system with simply adjusting time scale on the basis of fixed structure of ADRC.Finally, compared and analysed the variance of control action between the PID controllers and the ADRC controllers, the radical result show that ADRC controller can direct the couple system without decoupling it. The simulation results show its validity. |
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