An investigation of the design and control of shape memory alloy adaptive tuned vibration absorbers.

摘要

This research investigates the design and control of an adaptive tuned vibration absorber (ATVA) using shape memory alloy (SMA) adaptive-stiffness elements. Variation of the ATVA natural frequency of up to 15% is achieved by heating the SMA elements. The SMA ATVA can thus be tuned to attenuate the vibration of a primary system across a band of frequencies. The on-line modification of passive elements represents an adaptive-passive approach to vibration control. Benefits of the adaptive-passive approach to vibration control are improved performance over strictly passive methods and increased simplicity of design and implementation, when compared to conventional active control methods.;A proportional-integral controller was developed to on-line tune the SMA ATVA to achieve the appropriate tuned condition to minimize the vibration of the primary system at an unknown or uncertain excitation frequency. Certain nonlinearities in the SMA ATVA system required innovative controller design techniques. A Lyapunov analysis of the system indicated stability in the absence of control effort saturation, but was inconclusive when the saturations were included. A further phase-plane analysis provided additional insight for the design of an anti-windup algorithm to augment the original proportional-integral controller and guarantee closed-loop system stability. The augmented controller resulted in substantially improved performance of the control system and may be the foundation for future research in the areas of noise and vibration control, as well as a more general class of control problems.