International Conference on Electrical, Electronics, Signals, Communication and Optimization (EESCO) - 2015 Optimized Design of Au-Polysilicon Electrothermal Microgripper for Handling Micro Objects Presented By : - Abhijeet Pasumarthy Deptt. of Electronics & Communications Birla Institute of Technology Mesra

OVERVIEW : Introduction Principle of Operation of Microgripper Proposed Microgripper Design Observations & Results Future Scope References

INTRODUCTION : MEMS  Micro-Electro-Mechanical-Systems It is the technology of very small devices. MEMS enables the combination of sensors, actuators, mechanical components and also electronics on a single base (Si or Ge). Has the most wide-spread applications. Billion Dollar Industry. Lot of scope for inventions.

VARIOUS ADVANTAGES OFFERED BY MEMS OVER TRADITIONAL SENSING TECHNIQUES: Smaller package size.  Lower cost. Large-scale integration. Lighter weight. Less power consumption.  Wider operating temperature . Higher output signal.

MICROGRIPPERS : Finds its application in micro-robotics and micro-surgeries. Different actuation schemes exist: Piezoelectric Electrostatic Vacuum Electromagnetic Electrothermal There exist two types of electrothermal actuators: Bimorph actuator. Single material electrothermal compliant (ETC) actuator.

WORKING PRINCIPLE : Fig. 2. Electrical equivalent of the actuator. Fig. 1. Electrothermal actuator. Fig. 2. Electrical equivalent of the actuator.

GOVERNING EQUATIONS USED IN COMSOL: Electric potential applied to the Anchor Pads Joule’s Law Heat transfer in solids Thermal Expansion Law

PROPOSED MICROGRIPPER DESIGN : Fig. 3. Top View of the microgripper in XY plane. Fig. 4. Substrate View of the microgripper in XY plane.

MESHING : Fig. 6. 3-D view of the microgripper after applying a mesh. Fig. 5. Top View of the microgripper after applying a mesh. Fig. 6. 3-D view of the microgripper after applying a mesh.

Current Density (A/m­­­2) Data Analysis : Input Voltage (Volt) Total Displacement (µm) Stress (N/m2) Current Density (A/m­­­2) 1.15 x 10-15 1.85 x 10-9 0.25 0.54 6.39 x 106 9.66 x 108 0.5 2.16 2.56 x 107 1.93 x 109 0.75 4.85 5.77 x 107 2.93 x 109 1.0 8.59 1.03 x 108 3.86 x 109 1.25 13.4 1.61 x 108 4.83 x109 1.5 19.1 2.31 x 108 5.8 x 109 1.75 25.7 3.13 x 108 6.77 x 109 2.0 33.1 4.06 x 108 7.73 x 109 2.25 41.1 5.06 x 108 8.7 x 109 2.5 49.5 6.12 x 108 9.67 x 109 2.75 58.1 7.21 x 108 10.6 x 109 3.0 67.6 8.31 x 108 11.6 x 109 Table 1. Analysis of parameters: Total displacement, Stress & Current Density vs the input voltage.

OBSERVATIONS : Fig. 11. Stress vs applied voltage. Fig. 12. Total displacement vs applied voltage.

OPTIMIZATION FACTORS : Length of hot arm. Width of cold arm. Material conductivity. Thickness of the structure. Connector width.

SIMULATION :

FUTURE SCOPE : More composite actuation systems can be implemented. Efficient performance yielding materials can be used. Complex structures can be designed as per requirement.

REFERENCES : Xinhan H., Jianhua C., Min W. and Xiadong L., “A piezoelectric bimorph micro-gripper with micro-force sensing”, IEEE International Conference on: Information Acquisition p.5 (2005). S. M. Karbosi, M. Shamshrisar, M. Naraghi and M. Manoufi, “Optimal design analysis of electro thermally driven micro-actuators”, Microsystem. Technol, pp. 1065-1071, (2010). Nikolas Chronis and Luke P.Lee, “Electrothermally activated SU-8 Microgripper for single manipulation in solution”, J. Micro electro Mechanical Syst., 4, pp.857-863 (2005). Q. A. Huang and N. K. Lee, “Analysis and design of polysilicon thermal flexure actuator, J. Micromech. Microeng. 9, pp. 640, (1999). R. S. Chen, C. Kung, and Gwo-Bin Lee, “Analysis of the optimal dimension on the electro-thermal micro-actuator”, J.Micromech. Microeng. 12, pp. 291-296, (2002). A.Geisberger, N.sarkar, M.Ellis and G.D.Skidmore, “Electrothermal properties and modeling of polysilicon Microthermalactuators”, J.Micro electro Mechanical Syst., 12, pp. 513-523, (2003). Ang Beng Seng, Zuraini Dahari, Othman Sidek, Muhamad Azman Miskam, 2009 “ Design and Analysis of Thermal Micro-actuator”, European Journal of Scientific Research, ISSN 1450-216X Vol.35 No.2, pp 281-292.

THANK YOU