Real-time vibration control of a flexible structure using an augmented feedforward and feedback scheme

This paper presents an augmented control scheme of combined feedforward and feedback control methods for real-time input tracking and vibration suppression of the vertical movement of a multi-input multi-output twin rotor system (TRMS). A PID compensator is initially designed and implemented for input tracking control. There are often strong limitations to the use of feedback methods to control resonance modes, due to sensor noise and system's flexible dynamics. The control scheme is thus extended to incorporate feedforward control method for vibration suppression of the TRMS. A 4-impulse input shaper is used to pre-process the command signal applied to the system. The proposed augmented control scheme is designed and implemented on the actual system using the real time kernel that provides a mechanism of real time measurement and control of the actual plant. Experimental results of the response of the TRMS with the proposed control scheme are presented in time and frequency domains. The proposed scheme is found to be simple, practical and effective. As a result the system's oscillations are reduced and the performance of feedback method is improved.