This paper presents the results of experimental tests of a new proof mass actuator that can be used to implement a velocity feedback loop to reduce the flexural vibration of large flexible structures. Classical proof mass actuators used in vibration control systems require low fundamental resonance frequency to produce a constant force effect at the control position in the desired frequency range. The actuator considered in this study uses a piezoelectric stack transducer, which is characterised by large force and small stroke properties. Thus, to meet the requirement of low resonance frequency, the actuator should be equipped with a large proof mass. However, in this case when the actuator is exposed to shocks the piezoelectric transducer undergoes large deformations, which may lead to cracks. Also, the bulky proof mass limits the range of applications in which the actuator can be used. The actuator presented in this paper includes an additional flywheel element that produces an apparent mass effect without increasing the proof mass. As a result, the fundamental resonance frequency of the actuator is lowered without increasing the total weight of the suspended mass. This leads to both a more robust feedback loop with higher vibration control performance and a more robust actuator to shocks and large disturbances. The paper presents the measured frequency responses functions that characterise the electro-mechanical response of the proposed flywheel piezoelectric actuator, which are contrasted with simulations obtained from a simplified lumped parameter model.
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