A novel micro gripper integrating micro tri-axial force sensor and two-grade displacement amplifier is presented bases on piezoresistive detection and using PZT as its micro driving component. The micro tri-axial force sensor consisting of a flexible cross-structure realized by Deep Reactive Ion Etching (DRIE) is fabricated on a single-crystalline-silicon by MEMS technology.The arms of the cross-structure are connected to a silicon frame and to the central part of the cross-structure. After modeling the amplifier structure of micro gripper and the sensor

Finite Element Method (FEM) is used to analyze the displacement of the micro gripper and the deformation of the elastic cantilever. Then the calibration method of tri-axial sensor based on the microscopic vision and the cantilever beam's principle is proposed. The experimental results show that the major feature of the sensor are the high level of intrinsic decoupling of the signals from strain gauge

high resolutions in all three axes

high linearity

repeatability and simple calibration. In addition

they also show the micro gripper is reasonable and practical. The sensor is capable of resolving forces up to 10 mN with resolution of 2.4 μN in

x

axis and

y

axis and up to 10 mN with resolution of 4.2 μN in

z

axis; the maximal gripping displacement of the micro-gripper is 274 μm under a driving voltage of 200 V.