Abstract
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.