Piezoelectric bimorph charge mode force sensor

In this work, an analytical model, a finite element analysis and measured results for a planar, parallel and symmetrical piezoelectric bimorph structure are presented. The bimorph consists of two rectangular piezoelectric strips that are connected back-to-back on a thin metallic centre electrode. The bimorph is intended to be used as a millinewton range force sensor with dynamic excitation. The bimorph is modelled with a static, analytical expression for generated charge, voltage, displacement and force that correspond to the deflection of a freely oscillating piezoelectric bimorph. Also, a case where the movement of the bimorph is blocked is analyzed. A circuit that is used to actuate the bimorph is presented, as well as the measured results from the actuator and the sensor side of the bimorph in both free oscillation and blocked cases. The measurement results show a reasonably good agreement with the analytical model and very good agreement with the FEM model. Force sensor setup and a way to measure the force inflicted on the bimorph are also presented, as well as the force response of the bimorph against a commercial piezoresistive force sensor.

[1]  Paul Moses,et al.  A bimorph based dilatometer for field induced strain measurement in soft and thin free standing polymer films , 1998 .

[2]  Jari Juuti,et al.  Characteristics of piezoelectric cantilevers embedded in LTCC , 2007 .

[3]  Chengkuo Lee,et al.  Deflection detection and feedback actuation using a self‐excited piezoelectric Pb(Zr,Ti)O3 microcantilever for dynamic scanning force microscopy , 1996 .

[4]  Ken Haenen,et al.  Wide range pressure sensor based on a piezoelectric bimorph microcantilever , 2006 .

[5]  T. Itoh,et al.  Smart Piezoelectric PZT Microcantilevers with Inherent Sensing and Actuating Abilities for AFM and LFM , 1996 .

[6]  S. Kudo,et al.  Piezoelectric Actuator of LiNbO3 with an Integrated Displacement Sensor , 1998 .

[7]  T. Itoh,et al.  Self-excited force-sensing microcantilevers with piezoelectric thin films for dynamic scanning force microscopy , 1996 .

[8]  Fumihito Arai,et al.  Novel Force Sensor Using Vibrating Piezoelectric Element , 2005, Proceedings of the 2005 IEEE International Conference on Robotics and Automation.

[9]  J. G. Smits,et al.  Determining material stiffness using piezoelectric bimorphs , 1996, 1996 IEEE Ultrasonics Symposium. Proceedings.

[10]  Arvi Kruusing,et al.  Analysis and optimization of loaded cantilever beam microactuators , 2000 .

[11]  Fumihito Arai,et al.  Microknife using ultrasonic vibration , 2000, MHS2000. Proceedings of 2000 International Symposium on Micromechatronics and Human Science (Cat. No.00TH8530).

[12]  J. Dias Rodrigues,et al.  Active vibration control of a smart beam through piezoelectric actuation and laser vibrometer sensing: simulation, design and experimental implementation , 2007 .

[13]  I. Rangelow,et al.  Micromachined atomic force microscopy sensor with integrated piezoresistive sensor and thermal bimorph actuator for high-speed tapping-mode atomic force microscopy phase-imaging in higher eigenmodes , 2003 .

[14]  M. Rutland,et al.  Techniques for measuring surface forces , 1996 .

[15]  T. Maeder,et al.  Fabrication of a Millinewton Force Sensor Using Low Temperature Co-fired Ceramic (LTCC) Technology , 2007 .

[16]  A. Ballato,et al.  Network representation for piezoelectric bimorphs , 1991, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[17]  J. Sirohi,et al.  Fundamental Understanding of Piezoelectric Strain Sensors , 1999, Smart Structures.

[18]  I. Bársony,et al.  Three dimensional single crystalline force sensor by porous Si micromachining , 2004, Proceedings of IEEE Sensors, 2004..