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http://dx.doi.org/10.5370/KIEE.2017.66.1.66

On the Robustness of Disturbance Observer based Controller for DC Motor with Unstructured Uncertainty  

Jo, Nam-Hoon (Dept. of Electrical Engineering, Soongsil University)
Publication Information
The Transactions of The Korean Institute of Electrical Engineers / v.66, no.1, 2017 , pp. 66-71 More about this Journal
Abstract
In this paper, we study the robustness of disturbance observer based controller for DC motor in the presence of unmodeled dynamics. It is well known that the robustness property usually becomes weaker as the control gain becomes larger. On the contrary to this expectation, it is shown that the phase margin of DOB controller remains quite a large value even though the time constant of Q-filter becomes smaller. The computer simulation results show that DOB controller is able to stabilize the motor system even in the presence of unmodeled dynamics. On the contrary, the unity-feedback system fails to maintain stability when a high gain feedback is employed for the purpose of achieving better disturbance attenuation performance.
Keywords
Disturbance observer(DOB); Unmodeled dynamics; DC motor; Unstructured uncertainty;
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