A COMPARATIVE STUDY OF THE EFFECTIVENESS OF PI- AND ROBUST CONTROLLERS IN THE DESIGN OF HIGH-ACCURACY TRACKING SYSTEMS
In the article the problem of achieving the best velocity error constant in the design of a high-accuracy tracking system with an elastic two-mass electromechanical object is investigated. A typical two-loop structure with an internal speed system and an external tracking loop with a proportional controller is considered. The main efforts are aimed at obtaining the best robust dynamics of the speed system. For this purpose, the robust control based on H∞-theory has been used. In order to demonstrate the advantages of a system with robust control, a tracking two-loop comparison system with a PI controller in the internal loop is designed on the basis of the cascade control principle. The stability of the tracking system is investigated with the aim of finding the highest velocity error constant, at which the robustness is preserved without regard to variations in the parameters of the electromechanical object. Robustness is qualitatively estimated by means of preserving the dynamic performance measures while changing the parameters of the electromechanical object – the rigidity of mechanical coupling between the motor and the mechanism driven by it, as well as the moment of inertia of the second mass in a two-mass system. Comparative modeling has shown that the tracking system with a robust controller copes effectively with disturbances (both deterministic and random processes), and demonstrates the improved dynamic accuracy in the reproduction of test signals (both stepped and sinusoidal).
Authors: N. D. Polyakhov, D. Ph. Nguyen, V. B. Vtorov, V. E. Kuznetsov, I. A. Prikhodko, A. D. Stotskaia
Direction: Automation and Control
Keywords: PI-, PID2-controller, robust control
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