Authors: MEHMET ÖNDER EFE, COŞKU KASNAKOĞLU
Abstract: This paper presents a modification to the original disturbance observer based control (DOBC) scheme byredefining the lowpass filter using a nonlinear element. The proposed technique improves the disturbance predictionperformance for both small and large magnitude disturbance signals. The contribution of the current work is to unfoldthe stability and performance conditions under the proposed modification. A comparative set of simulation studies arediscussed and it is seen that the proposed modification results in smaller disturbance prediction error energy and smallertracking error energy when the plant model is discrete time and uncertain.
Keywords: Discrete time disturbance observer, robust control, nonlinear Q-filter, S-filter
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