Experimental Validation and Vibration Analysis of a Flexure Parallel Mechanism for Nano-Positioning Application

n this paper, the dynamic modeling and experimental results of a new compliant mechanism for the nano positioning applications have been investigated. This compliant mechanism is a monolithic mechanism with six circular flexure hinges which has three degrees of freedom in the plane of motion. This compliant mechanism is designed for the positioning of samples in Scanning-Electron- Microscope (SEM). Also, this nano- positioning mechanism has parallel structure in order to obtain high accuracy. For kinematic and dynamic modeling, intermediate and thick type of flexure hingeswas adopted and all the intermediate links are assumed to be flexible. The equations of motion are derived via Kane’s equation of motion. Also, the Assumed Mode Method theory is used to model the structural flexibility of the intermediate links and then Natural frequencies of the intermediatelinks are obtained. For the experimental investigation, this compliant mechanism was made by a wire- cutting machine. To obtain vibration properties, experimental modal test was performed and also the lateral displacement of each link was measured in the resonant frequencies. The purpose ofthe modal test is to determine the resonant frequencies of present compliant mechanism under the two different boundary conditions. Two boundary conditions were adopted to performing modal test are free-free and clamped- free boundary conditions. Subsequently, the results of experimentalmodal tests for two different types of boundary conditions are obtained and compared with the Finite Element Method (FEM) results to verify their accuracies. The results are shown that the FEM results were in the very close agreement with the experimental results. Finally, for further verification,the results of analytical equations were compared with FEM results.

Keywords:

Compliant Mechanism , Experimental , Nano-positioning , Modal test , FEM