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UM E-Theses Collection (澳門大學電子學位論文庫)

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Title

The analysis and optimal design of compliant mechanisms

English Abstract

Compliant mechanisms have emerged as an important advancement in micro/nano-manipulators. Compliant mechanisms are designed with flexure hinges in most cases. The analysis and design of a flexure hinge is very complicated because of its variable section. In this thesis, the compliance equations of genetic flexure hinges (circular right flexure hinges, elliptical flexure hinges, corner-filleted flexure hinges and rectangle flexure hinges) are proposed based on the Castigliano’s second theorem. The relative errors between the calculation results and the simulation results are less than 5%. The relationship between the geometrics parameters of flexure hinges and the compliances are also studied. In addition, this thesis presents three new empirical stiffness equations for corner-filleted flexure hinges with a wide range of tl ratios ( 0.02 < = t / l < = l ) under large deformation using the FEA method. The relative error is found to be less than 6%. Thus, the compliance matrixes and the new empirical stiffness equations for flexure hinges can be easily used in the design of compliant mechanisms. The dynamics models of a compliant differential displacement amplifier and a compliant parallel-guiding mechanism are built based on the Lagarange’s equation. Secondly, the dynamics model of a compliant parallel-guiding mechanism is built using the numerical method. Moreover, the dynamics characteristics of the compliant parallel-guiding mechanism with flexure hinges are analyzed. The relationship between the fundamental natural frequency and the geometrics and material parameters of the mechanism are studied. In addition, the reliability and sensitivity of a right circular flexure hinge have been analyzed. Further, according to the results of reliability analysis, the structure optimization based on the reliability can be implemented in the future work. A novel compliant parallel XY micro-motion stage is presented to fulfill positioning and manipulation with micro/nanoscale precision. The novel stage is a totally decoupled structure, which is composed of compliant differential displacement amplifiers and compliant parallel-guiding mechanisms. The amplifiers adopt right circular flexure hinges, while the parallel-guiding mechanisms adopt flexible links. The flexible links have much better compliance performance than flexure hinges when the deformation is large. The amplification ratio of the novel stage is 10.09, and the fundamental natural frequency is 18.02Hz.

Issue date

2015.

Author

Xu, Jia

Faculty

Faculty of Science and Technology

Department

Department of Electromechanical Engineering

Degree

M.Sc.

Subject

Mechanical movements

Mathematical optimization

Supervisor

Li, Yang Min

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Location
1/F Zone C
Library URL
991000739889706306