Design And Fabrication Of Micro Actuator Based On Piezoelectric Thick Film

Micro piezoelectric actuators possess the advantages of lightweight structure,rapid response,low speed,high torque and high electromagnetic compatibility,therefore present great potential in high resolution application of micro robots,precision positioning,medical equipment as well as in the case which has high requirements on the structure size.This thesis is aimed to design and fabricate a micro piezoelectric actuator with a length/diameter ratio of less than one based on the PZT thick films.The piezoelectric simulation model of the micro piezoelectric actuator is established by ANSYS to solve the mode shape,resonance frequency and vibration amplitude.Annular PZT thick films were prepared on the titanium elastomer by using electrohydrodynamic jet technique and the micro piezoelectric actuator was processed by annealing crystallization and partition polarization,which simplifies the preparation process of the conventional piezoelectric actuator.In this theis,firstly,the structure and operational mechanism of the micro piezoelectric actuator were analyzed.The formation of travelling wave on the piezoelectric actuator was deduced from the theoretical formulas.The structure of micro piezoelectric actuator with PZT thick films on the titanium elastomer was designed.The piezoelectric simulation model of the micro piezoelectric actuator was established.The modal analysis,harmonic response analysis and transient dynamics analysis was conducted,respectively.The resonance frequency at different modals,the vibration amplitude at frequency domain and time domain of the micro piezoelectric actuator were solved.The impact of actuator dimensions and the teeth structure on the resonance frequency were studied.Secondly,the PZT composite suspension based on the PZT sol and PZT powder was prepared.The software of electrohydrodynamic jet technique was developed.The titanium elastomer and the top electrode mask with 6 divided zones was previously manufactured.The annular PZT thick film was fabricated on the titanium elastomer by using electrohydrodynamic jet technique.The PZT thick film annealed for crystallization and polarized.And then the micro piezoelectric actuator with outetr diameter of 4 mm was fabricated.Finally,the PZT thick film and piezoelectric actuator was characterized.Vibration test was conducted by using laser doppler vibrometer.The results show that the piezoelectric actuator has a resonance frequency of 79.14 kHz and a Z-direction amplitude of 0.176 μm under the voltage excitation of 10 V amplitude.The errors with harmonic analysis and transient analysis results are 2% and 2.25%,respectively.The impedance of the piezoelectric actuator was tested by an impedance analyzer.The results show that the resonance frequency of the piezoelectric actuator is 79 kHz,which is 2.2% compared with the harmonic analysis.