1. Research Introduction Lab of Smart Structures 精密机械与精密仪器系 Precision Machinery and Precision Instrumentation

2. Contents 精密机械与精密仪器系 Precision Machinery and Precision Instrumentation 4. Energy harvesting 3. Precision control of piezoelectric actuators 2. Piezoelectric transformers 1. Smart piezoelectric actuators 5.Other researches

3. 1.Small Piezoelectric Actuators a. Fiber torsional actuator b. Tube actuators and its composite

4. discovery a. Discovery of torsional actuation

5. Test setup Static response of voltage Dynamic response of frequency C. L. Pan, Z. H. Feng, et al., "Small torsional piezoelectric fiber actuators with helical electrodes,“ Applied Physics Letters, vol. 92, p. 012923, 2008. Resonance image of the prototype actuator’s free end. Experimental measurement

6. Piezoelectric fiber motorBulk piezo cylinder moter Application—Impact piezoelectric motor Rotor

7. Impact response of the fiber motorImpact response of the bulk motor W. X. Han, Z. H. Feng, et al., "An impact rotary motor based on a fiber torsional piezoelectric actuator," Review of Scientific Instruments, vol. 80, p. 014701, 2009. Impact piezoelectric motor

9. For a 15 mm length fiber: Torsional vibration, 0-30 kHz bandwidth, 0.2° amplitude Longitudinal vibration, 0-50 kHz bandwidth, 1 μm amplitude It consists of cantilevers, hinges, and mirror. Designed structure Miniature optical scanning mirror

10. Principle of 2-D scanning

11. Fabrication and test

12. C. L. Pan, Z. H. Feng, et al., "Miniature orthogonal optical scanning mirror excited by torsional piezoelectric fiber actuator," Sensors and Actuators A: Physical, vol. 165, pp. 329-337, 2011. Measured vertical frequency response of the prototype scanners. Results

13. SPM: Scanning Probe Microscopy AFM: Atomic Force Microscope Voltage driving for getting x direction displacement Side view and top view of a piezoelectric tube b. Piezoelectric scanners used in SPM

14. Piezoelectric tubes with film electrodes on their outer and inner surfaces can be used to compose multitube actuators. The actuator of four piezoelectric tubes can substitute the traditional single-tube actuator. (a) single-tube actuator, (b) four-tube actuator. Advantages: 1.Much more accurate actuation can be achieved by deliberate arrangement of the four tubes. 2. Multitube structure has better performances under certain conditions. Multitube actuators

15. The end surface of the four-tube actuator. The trace of a distinct point on the actuator’s moving head. Experiments

16. Miniature tubular centrifugal piezoelectric pump The structure of the centrifugal pump using wobbling motion of a metal tube to push the liquid out. (a)The mechanical structure of a prototype pump. (b) The photograph of the prototype pump. Y. T. Ma, Z. H. Feng, et al., "Miniature tubular centrifugal piezoelectric pump utilizing wobbling motion,“ Sensors and Actuators A: Physical, vol. 157, pp. 322-327, 2010.

17. 精密机械与精密仪器系 Precision Machinery and Precision Instrumentation Experimental measurement Flow rate at different driving frequencies, under 120Vp-p driving voltage and 2.0 kPa backpressure. A maximum flow rate of 7.7ml/min occurs at 232Hz. 。 120V p-p 2.0kPa 233.2Hz The relationship between the flowrate and backpressure at different driving voltages shows a good linearity.

18. Structure of the stator:Structure of the prototype motor: Stiffness 2.5N/mm (a)dimensions of the stator (b) stator settled on the base. (a)Sectional drawing (b) external appearance. Two-Phase Piezoelectric Motor

19. Angular speed, output power, and efficiency versus load Angular speed versus driving voltage amplitude. Experimental measurement result Y. T. Ma, Z. H. Feng, et al., "Two-Phase Piezoelectric Motor Using a Multiple-Tube Structure actuator,“ Japanese Journal of Applied Physics, vol. 48, Sep 2009.

20. 2. Piezoelectric Transformer

21. Radiator heightens power density of piezoelectric transformers For a specific PZT-5H sample considered, this material can handle 330 W/cm 3 at 100 kHz in theory. However, the maximum output power density of current PTs is typically less than 30 W/cm 3 W. W. Shao, Z. H. Feng, et al., "Radiator heightens power density of piezoelectric transformers,“ Electronics Letters, vol. 46, p. 1662, 2010. Construction and dimensions of proposed piezoelectric transformer operating in contour-extensional vibration mode

22. Photograph of the prototype device PT: Roughness Ra 0.2 μm. copper plate ： Dimensions ： 32×25×1 mm3 Roughness Ra of 0.02 μm A layer of grease pad thickness 0.23 mm insulation and transfer heat. A spring with a stiffness of 1 N/mm is attached to a bolt ； a thread pitch of 0.5 mm to supply variable pressing force.

23. Results of test Based on this research, it is hoped to make metal-cased piezoelectric transformers, which will have wide application potential in many fields. When the input voltage increased to 150 V pp, the temperature rise of the free PT increased rapidly over 30 ºC and then continued up to a higher value. The characteristics of PT became quite unstable.

24. 3. Precision Control of Piezoelectric Actuators Charge pump controller

25. Hysteresis of piezoelectric actuators Piezoelectric actuators hysteresis Configuration of the voltage amplifier Configuration of the charge amplifier

26. 精密机械与精密仪器系 Precision Machinery and Precision Instrumentation Switched capacitor charge pump reduces hysteresis Principle of switched charge pump Piezoelectric actuators hysteresis Floating ground

27. 精密机械与精密仪器系 Precision Machinery and Precision Instrumentation Experimental setup

28. control with small steps. Displacement step is 15 nm control with large steps Displacement resonance of piezoelectric stack

29. 精密机械与精密仪器系 Precision Machinery and Precision Instrumentation The hysteresis of the voltage and charge drive Charge Voltage

30. The result of the three control methods 0.02Hz0.1Hz0.5Hz1Hz5Hz20Hz Voltage8.15%8.17%8.41%9.21%10.5%10.8% Charge9.37%9.19%7.16%4.21%0.2%4.65% Switch1.84%1.55%1.47%1.13%0.72%0.71% L. Huang, Z. H. Feng, et al., "Switched capacitor charge pump reduces hysteresis of piezoelectric actuators over a large frequency range," Review of Scientific Instruments, vol. 81, p. 094701, 2010.

31. Charge pump controller for grounded piezoelectric actuators Schematic charge pump controller for the grounded load

32. 4. Energy Harvesting

33. Maximum mechanical energy harvesting strategy for a piezoelement Proposed energy harvesting system using a piezoelectric element. Standard circuit for energy harvesting W. Q. Liu, Z. H. Feng, et al., "Maximum mechanical energy harvesting strategy for a piezoelement," Smart Materials and Structures, vol. 16, pp. 2130-2136, 2007.

34. For a fixed material and structure, the system would exhibit a better performance following the use of the control method suggested. This will greatly improve the design of the power generator. Analytical process Proposed cycle for output maximum energy

35. 精密机械与精密仪器系 Precision Machinery and Precision Instrumentation Right-angle piezoelectric cantilever Right-angle cantilever uniform strain distribution of piezoelement

36. Strain distribution in the surface of PZT element during vibration. Frequency response for the two devices at sinusoidal vibration amplitude of 2.5 m s −2. Results of test It has been determined that the competence of the right-angle cantilever for energy harvesting under a strain limit is 2 times larger than that of the traditional cantilever. The right-angle cantilever system produces more electrical energy compared to a traditional cantilever. J. W. Xu, Z. H. Feng, et al., "Right-angle piezoelectric cantilever with improved energy harvesting efficiency," Applied Physics Letters, vol. 96, p. 152904, 2010.

37. 精密机械与精密仪器系 Precision Machinery and Precision Instrumentation Outline drawing of the wind-energy-harvesting device. Piezoelectric Wind-Energy-Harvesting Device with Reed and Resonant Cavity Equivalent circuit

38. The relationships between output power, the load resistance, and the wind speed. Output power and the energy conversion efficiency with a resistive load 0.46MΩ J. Ji, Z. H. Feng, et al., "Piezoelectric Wind-Energy-Harvesting Device with Reed and Resonant Cavity," Japanese Journal of Applied Physics, vol. 49, p. 050204, 2010. Results of test The device was investigated with a wind speed ranging from 2.8 to 10m/s. An output power of 0.5–4.5mW was obtained with a matching load of 0.46MΩ. The energy conversion efficiency of the device could reach up to 2.4%.

39. 5. Other Researches

40. The equivalent circuit of a piezoelectric sensor linked with a voltage amplifier. The equivalent circuit of a piezoelectric element linked with a charge amplifier. Signal Conditioning Methods for Piezoelectric Sensors

41. W. Q. Liu, Z. H. Feng, et al., "The influence of preamplifiers on the piezoelectric sensor’s dynamic property," Review of Scientific Instruments, vol. 78, p. 125107, 2007. Experimental setup. The influence of preamplifiers on the piezoelectric sensor’s dynamic property

42. A High-sensitive Static Vector Magnetometer based on 2D vibration Schematic diagram of device configuration Reflection method to measure vibration angle Two Vibrating Coils The linear range is about 100 μT, which is available in earth magnet detection, navigation, vehicle detection and so on.

43. Science

44. High-speed Electrically Actuated Elastomer

45. 精密机械与精密仪器系 Precision Machinery and Precision Instrumentation