Structural vibration control using an active resonator absorber: modeling and control implementation

A new dynamic vibration absorber referred to as an active resonator absorber (ARA) is proposed; we explore its practical implementation using piezoelectric ceramic (PZT) inertial actuators. The ARA is a passive absorber with an additional dynamic feedback compensator within the PZT actuator. Without any controller, it becomes a passive vibration absorber due to internal damping and elasticity properties of the piezoelectric materials; hence, it is inherently fail-safe. For active operation, the compensator parameters are designed such that a resonance condition is intentionally created within the absorber subsection to mimic the vibratory energy from the system of concern to which it is attached. The resonance condition can be created through the appropriate design of the compensator and implemented through adjusting the external electrical voltage applied to the PZT actuator. Although PZT materials inherently possess nonlinear characteristics (e.g., hysteresis), an equivalent linearized model is developed for the actuator subsystem. An experimental set-up is then constructed to validate the proposed linearized model and estimate the actuator parameters using a nonlinear least squares algorithm. Because the parameters of the PZT actuators (i.e. stiffness, damping, and effective mass) are approximate, the compensator designs based on these parameters would result in partial vibration suppression when utilized in real applications. An auto-tuning method is used to effectively tune the compensator parameters to improve the vibration suppression quality. The effectiveness and stability of the proposed auto-tuning scheme when implemented on a single-degree-of-freedom primary system are demonstrated.