A Microgripper Integrated 3-D MEMS Force Sensor

Micromanipulation is an important emerging technique developed mainly during the past decade, which is widely applied in the fields of micro system, bio-engineering, microsurgery manipulation, and so on. Most of the cases, operators manage to manipulate the objects with the optical microscope, when the size of the objects is some microns to submillimeters. Two dimensional image is not enough to manipulate micro objects precisely and reliable during the process of micromanipulation, for there is complex interactive force between the objects and tools. Microgripper is the main tool in micromanipulation and microassembly. By far, there are several kinds of microgripper, but force information is not available or is limited in only one direction. And therefore, it is necessary to develop a microgripper with multi-sensor.After lots of papers related microgripper and microforce sensor consulted, a microgripper with 3 dimensional force sensor is presented from the point of microscopic field and according to the driving method. A micro displacement amplifier based on flexible hinges is designed, modeled and analyzed. And after the structure simulated by the aid of the Finite Element Method (FEM) software ANSYS, the optimal parameters are approached.A MEMS micro force sensor suitable for the microgripper is achieved which is based on piezoresistance effect of semiconductor. The operating principle of micro force sensor is presented, and modeling, analyzing the structure, achieving the best parameters. Then bring forward the fundamental designing principle of piezoresistance sensor, select the fitting material. The position of force sensing resistance is determined according to the result of force analyse. The size and the value of resistance is designed. And indicate the chip fabricating process after micro mechanism technology introduced.In this paper, aimed at the characteristic of sensor acting force, a kind of calibration is proposed using cantilever. The cantilever and calibration device are designed, a linear calibration method is introduced. Then the calibration experiment is performed, and the calibration matrix is solved. The static performances were tested. The experimental results prove that the design specifications are met.