ROBUST TIME-DELAY CONTROL OF MULTIMODE SYSTEMS

This paper presents a procedure for the design of open loop controller s for flexible structures using multiple step inputs delayed in time. The controller attenuates the residual vibration by cancelling the com plex poles of the system. Robustness is achieved by locating additiona l zeros at the cancelled poles of the system. The paper begins by addr essing the control of a single mode and examines the effect of user se lected time-delays on robustness and the reference input. Next, a proc edure for the design of robust time-delay controllers for multiple mod es with user selected time-delays is considered. This is followed by a design of a minimum time-delay controller, such that the step input m agnitudes are constrained to values between 0 and 1. Two examples, a s pring-mass system and a single-link flexible-arm robot are used to ill ustrate the effectiveness of the proposed controller.