Optimization-Based Approach to the Embodiment Design of Compliant Mechanisms with Different Flexure Hinges

In various applications compliant mechanisms allow a reduction of mass, assembly and manufacturing effort through the integration of functions into fewer parts and an increasing precision through less wear and backlash. Due to the variety of geometric parameters and the complex relation between loads, deformation and strain, the dimensioning of flexure hinges is still a challenging task. This paper presents a new optimization-based approach to the embodiment design of an exemplary chosen compliant gripper mechanism with different corner-filleted flexure hinges. Based on a rigid-body model, loads and rotation angles for the dimensioning of each hinge are deduced. A linear finite-beam model is used to analyze the corresponding strain. Through the application of the box-complex method, chosen dimensions of the flexure hinges are optimized, resulting in a suitable embodiment design with an admissible maximum strain and a minimized installation space. The optimization results are successfully evaluated with regard to their distribution over multiple repetitions and the accuracy compared to a three-dimensional FEM model.

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