Active Vibration Control of Meso- and Microstructures via Piezoelectric Films

The purpose of this paper is to demonstrate the feasibility of active vibration control for meso- and microstrucutres through use of PZT (Lead-Zirconium-Titanium Oxide) thick films. This paper consists of two parts. The first part is to develop a sol-gel process to fabricate crack-free PZT thick films with thickness of 2 microns and area of 4 mm × 4 mm. The PZT thick film has a Pt/Ti bottom electrode and a gold top electrode. Moreover, the PZT thick film is fabricated on a silicon cantilever, whose dimensions are 20 mm × 15 mm × 0.4 mm. The second part is an experimental demonstration of active vibration control using the PZT thick film. In the experiment, a tiny bulk PZT patch is first glued to the silicon cantilever. A function generator drives the bulk PZT simulating a source of disturbance exciting the silicon cantilever. In the meantime, a laser Doppler vibrometer (LDV) measures velocity of the cantilever tip. With a phase shifter as the controller, the LDV measurement is fed back to the PZT thick-film actuator to actively control the cantilever vibration. To evaluate the effectiveness of the active vibration control, a spectrum analyzer measures the frequency response functions (FRF) from the bulk PZT voltage to the LDV response. Experimental results show that the simple active vibration control scheme can reduce resonance amplitude of the first bending mode by 66%.