Closed-Loop Input Shaping Control of Vibration in Flexible Structures via Adaptive Sliding Mode Control

Ming-Chang Pai

doi:10.1155/2012/803479

Abstract

Input shaping technique is widely used in reducing or eliminating residual vibration of flexible structures. The exact elimination of the residual vibration via input shaping technique depends on the amplitudes and instants of impulse application. However, systems always have parameter uncertainties which can lead to performance degradation. In this paper, a closed-loop input shaping control scheme is developed for uncertain flexible structures. The algorithm is based on input shaping control and adaptive sliding mode control. The proposed scheme does not need a priori knowledge of upper bounds on the norm of the uncertainties, but estimates them by using the adaptation technique. This scheme guarantees closed-loop system stability, and yields good performance and robustness in the presence of parameter uncertainties and external disturbances as well. Furthermore, it is shown that increasing the robustness to parameter uncertainties does not lengthen the duration of the impulse sequence. Simulation results demonstrate the efficacy of the proposed closed-loop input shaping control scheme.

Highlights

Numerous techniques have been proposed to reduce the residual vibration in flexible structures since the residual vibration can often have adverse affects on the operational performance and accuracy
One drawback of this method is that the exact cancellation of the residual vibration depends on the amplitudes and instants of impulse application which are related to system parameters
The exact elimination of the residual vibration via input shaping technique depends on the amplitudes and instants of impulse application

Summary

Introduction

Numerous techniques have been proposed to reduce the residual vibration in flexible structures since the residual vibration can often have adverse affects on the operational performance and accuracy. Known as input shaping [1,2,3,4,5], has been implemented to control the residual vibration on a variety of systems. Input shaping is implemented by a sequence of impulses, called the input shaper, together with a desired system command, and yields the system input that yields the desired motion without vibration. One drawback of this method is that the exact cancellation of the residual vibration depends on the amplitudes and instants of impulse application which are related to system parameters. If amplitudes or instances at impulse application are inaccurate, the residual vibration can lead to system performance degradation. Input shaping method does not deal with vibration excited by external disturbances

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