A new optimal synthesis method for designing compliant mechanisms.

摘要

The field of distributed-compliance mechanisms has seen significant work in developing suitable topology optimization tools for their design. These optimal design tools have grown out of the techniques of structural optimization. This proposed work builds on the previous work in topology optimization and compliant mechanism design by proposing an alternative design space parameterization through control points and adding another step to the process, that of subdivision. The control points assist a specific design to be represented as a solid model during the optimization process. The process of subdivision creates an additional number of control points that help smooth the surface (for example a C 2 continuous surface depending on the method of subdivision chosen) creating a manufacturable design free of traditional numerical instabilities. Note that these additional control points do not add to the number of design parameters. This alternative parameterization and description as a solid model effectively and completely separates the design variables from the analysis variables during the optimization procedure. The motivation behind this work is to avoid several of the numerical instabilities that occur in topology optimization and to create an automated design tool from task definition to functional prototype created on a CNC or rapid-prototype machine. This proposed work will describe the compliant mechanism design process including subdivision and will demonstrate the procedure on several common examples. This work will also present the compliant mechanism design tool as applied to relaxation of certain design parameters to achieve more optimum designs. Relaxation has been shown to guarantee the existence of optimal solutions and eliminate mesh dependencies. This proposed work will demonstrate the application of relaxation to a control-point parameterization of the design workspace for the CM topology optimization process and to spatial locations of the control points. Based on this alternate parameterization, the principle of relaxation will demonstrate the increased utility of the control-point parameterization. This new parameterization scheme produces a material distribution solution that possesses ease of manufacturability and high functionality in design and application.