Abstract: The mathematical model, which can be used to calculate the critical force of compliant serial mechanism composed of right-angle-notch flexure hinges, is established by employing the approximative differential equation of the flexible curve of the material bending theory. The buckling critical coefficient of flexibility is defined, and the method is put forward, by which the value of the coefficient could be calculated. The finite element buckling analysis using commercial software ANSYS8.0 is carried out, and the result confirms the correct-ness of the mathematical model established above. The experi-mental equipment is developed to test buckling critical force of compliant serial mechanism. In order to reduce the influence of load dimension on buckling, the conception of load equivalent length is proposed. Experiments indicate that the experimental value is consistent with the theoretical one. Consequently, the mathematical model proposed above has high reference value, and it can be used as the directive theory for buckling optimiza-tion design of compliant serial mechanism.

Key words: Buckling critical force, Finite element analysis, Flexure hinges, Reliability, Dual-mode coupling drive, Mode shift, Predictive function control, Torsional damper, Electric vehicle