Design of a 2-DOF Flexure Platform for Unbalance Measurement

The traditional measurement platform for unbalance moment exploits the knife-edge as the support module but its performance rapidly deteriorates as the edge is worn down. In this paper, the flexure mechanism is utilized to overcome this drawback. The generalized cross-spring pivot is designed to achieve the approximate constant rotational stiffness and reduced center shift, which will benefit the control system and calibration procedure. A 2-DOF flexure mechanism is thus proposed by taking the practical application into account, such as manufacturability, performances of sensor and actuator. The finite element analysis (FEA) is carried out to verify the validation of design. Finally, the experiment is implemented and the results show a high accuracy: the error is less than 2.4g·mm even though the payload is up to 7kg and the unbalance moment is 100g·mm.