Piezoelectric self-sensing actuators used for vibration control have many advantages over non-collocated systems as they are lighter, less costly, and unconditionally stable for velocity feedback control. Self-sensing actuation allows a single piezoelectric element to be utilized as both a sensor and actuator. Since the control and sensing voltages both exist simultaneously in the piezoelectric material, a specially designed electric circuit, referred to as a bridge circuit, is required to realize the concept. However, precise equilibrium of the bridge circuit is difficult to maintain because the piezoelectric material properties are influenced by changes in environmental conditions. Loss of vibration control performance and stability results from bridge circuit imbalances. In this study, an array of mechanical thermal switches are used to passively control self-sensing bridge parameters in a piecewise fashion to maintain vibration control performance and stability over a wide range of environmental conditions. The original and modified self-sensing circuits were modeled analytically to simulate the effects of temperature changes on vibration control stability and performance. Compared to traditional self-sensing circuits, the addition of nine thermal switches was analytically shown to extend the stable operating range by 95°C while maintaining vibration control performance. The analytical simulations are being experimentally validated on a cantilevered beam system to show the addition of thermal switches to self-sensing circuits increases the stable operating range while retaining control system performance.
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