Electrothermal Microgripper With Large Jaw Displacement and Integrated Force Sensors

The novel design of a sensing microgripper based on silicon-polymer electrothermal actuators and piezoresistive force-sensing cantilever beams is presented. The actuator consists of a silicon comb structure with an aluminum heater on top and filled polymer in between the comb fingers. The sensor consists of a silicon cantilever with sensing piezoresistors on top. A microgripper jaw displacement up to 32 mum at a 4.5-V applied voltage is measured. The maximum average temperature change is 176 degC. The output voltage of the piezoresistive sensing cantilever is up to 49 mV at the maximum jaw displacement. The measured force sensitivity is up to 1.7 V/N with a corresponding displacement sensitivity of 1.5 kV/m. Minimum detectable displacement of 1 nm and minimum detectable force of 770 nN are estimated. This sensing microgripper can potentially be used in automatic manipulation systems in microassembly and microrobotics. [2008-0064].

[1]  J. Barnard,et al.  Effect of Ar gas pressure on growth, structure, and mechanical properties of sputtered Ti, Al, TiAl, and Ti3Al films , 1995 .

[2]  J. F. Creemer,et al.  Piezoresistive Cantilever Beam for Force Sensingin Two Dimensions , 2007, IEEE Sensors Journal.

[3]  B. Nelson,et al.  Monolithically Fabricated Microgripper With Integrated Force Sensor for Manipulating Microobjects and Biological Cells Aligned in an Ultrasonic Field , 2007, Journal of Microelectromechanical Systems.

[4]  Wen-Chau Liu,et al.  Anomalous temperature-dependent characteristics of silicon diffused resistors , 2003 .

[5]  P.M. Sarro,et al.  Integrated Silicon-Polymer Laterally Stacked Bender for Sensing Microgrippers , 2006, 2006 5th IEEE Conference on Sensors.

[6]  R. Buser,et al.  Tactile microgripper for automated handling of microparts , 1996 .

[7]  Lis K. Nanver,et al.  Optimization of fully-implanted NPNs for high-frequency operation , 1996 .

[8]  J. Wortman,et al.  Young's Modulus, Shear Modulus, and Poisson's Ratio in Silicon and Germanium , 1965 .

[9]  Byung Kyu Kim,et al.  Institute of Physics Publishing Smart Materials and Structures a Superelastic Alloy Microgripper with Embedded Electromagnetic Actuators and Piezoelectric Force Sensors: a Numerical and Experimental Study , 2022 .

[10]  L. Sperling.  Introduction to physical polymer science , 1986 .

[11]  Richard J. Farris,et al.  The characterization of thermal and elastic constants for an epoxy photoresist SU8 coating , 2002 .

[12]  N. Chronis,et al.  Electrothermally activated SU-8 microgripper for single cell manipulation in solution , 2005, Journal of Microelectromechanical Systems.

[13]  Gih-Keong Lau,et al.  Polymeric Thermal Microactuator With Embedded Silicon Skeleton: Part I—Design and Analysis , 2008, Journal of Microelectromechanical Systems.

[14]  T. Kenny,et al.  1/f noise considerations for the design and process optimization of piezoresistive cantilevers , 2000, Journal of Microelectromechanical Systems.

[15]  R. Feng,et al.  Influence of processing conditions on the thermal and mechanical properties of SU8 negative photoresist coatings , 2002 .

[16]  O. Hansen,et al.  Optimization of sensitivity and noise in piezoresistive cantilevers , 2002 .

[17]  Gih-Keong Lau,et al.  Polymeric Thermal Microactuator With Embedded Silicon Skeleton: Part II—Fabrication, Characterization, and Application for 2-DOF Microgripper , 2008, Journal of Microelectromechanical Systems.

[18]  Ole Hansen,et al.  Electro-thermally actuated microgrippers with integrated force-feedback , 2005 .

[19]  P. Sarro,et al.  2D electro-thermal microgrippers with large clamping and rotation motion at low driving voltage , 2007, 2007 IEEE 20th International Conference on Micro Electro Mechanical Systems (MEMS).

[20]  J. F. Creemer,et al.  Electrothermal microgripper with large jaw displacement and integrated force sensors , 2008, 2008 IEEE 21st International Conference on Micro Electro Mechanical Systems.

[21]  Wallace,et al.  Effect of strongly favorable substrate interactions on the thermal properties of ultrathin polymer films. , 1996, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[22]  Richard C. Jaeger,et al.  Off-axis sensor rosettes for measurement of the piezoresistive coefficients of silicon , 1993 .

[23]  P. French,et al.  The saturation current of silicon bipolar transistors at moderate stress levels and its relation to the energy-band structure , 2004 .

[24]  Paolo Dario,et al.  Micromechatronics in surgery , 2003 .

[25]  Pasqualina M. Sarro,et al.  Lateral nano-Newton force-sensing piezoresistive cantilever for microparticle handling , 2006 .

[26]  Neville K. S. Lee,et al.  Analysis and design of polysilicon thermal flexure actuator , 1999 .

[27]  G. K. Ananthasuresh,et al.  Comprehensive thermal modelling and characterization of an electro-thermal-compliant microactuator , 2001 .

[28]  Pasqualina M. Sarro,et al.  Polymer constraint effect for electrothermal bimorph microactuators , 2007 .

[29]  Arianna Menciassi,et al.  Force sensing microinstrument for measuring tissue properties and pulse in microsurgery , 2003 .