| In this study, the control of structural vibrations using shape memory alloy (SMA) actuators were developed theoretically, and preliminary results were verified experimentally. Based on an existing constitutive law and kinetic relations of one-dimensional shape memory alloys, an augmented dynamic model of the controlled structure and attached SMA actuators was developed. This model can be used for simulating, analyzing and designing control systems of structural vibrations using SMA actuators. Using the model, the thermomechanial process of SMA actuators and the interaction between the controlled structure and SMA actuators can be described. Based on the augmented model, a SMA wire-spring actuator suitable for structural vibration control was proposed, and the methodology of designing the SMA actuators used in vibration control was investigated. Simulation and experimental results showed that the SMA actuator can change the direction in phase transition region such that it has lower stress level and power consumption, and the design method gives a guidance for parameter choice of SMA actuators. For the proposed SMA actuators, sliding mode control (SMC) and H∞ optimal control were developed to design robust controller to take into account the uncertainties due to parameter variation, phase transformation and neglected high frequency dynamics. Simulation and experimental results showed that SMC controller and optimal H∞ controller do exhibit robustness for the uncertainties mentioned before and can provide satisfactory attenuation for shock and short duration excitation. This study especially stressed the thermomechanical process of SMA actuators and the effects of response of the controlled structure on the process. |
