Reduced Order CDM Controller Design for a Two-Inertia System

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Pantanee Boonyoung
Thavorn Bencharasut


CDM or Coefficient Diagram Method is one of powerful methods for designing a controller. The reduced order CDM controller design is proposed in this paper. The higher-order process is first reduced to be a reduced order model. Then the reduced order CDM controller is designed from the model by CDM with standard stability index for controlling the original higher-order process. In
this paper, the model of the two-inertia system is reduced to be a first-order model by Padé-type approximation method, Routh stability criterion and Stability equations approach. The experimental results in controlling speed of the two-inertia system using three types of the reduced order CDM controllers are quite similar.

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Boonyoung, P., & Bencharasut, T. (2023). Reduced Order CDM Controller Design for a Two-Inertia System. Journal of Advanced Development in Engineering and Science, 1(2), 17–22. Retrieved from
Research Article


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