An Intrinsic and Geometric Framework for Synthesis and Analysis ofDistributed Compliant Mechanisms.

Design of Bio-Inspired Mechanisms;Mechanical Engineering;Engineering;Mechanical Engineering

Krishnan, GirishLynch, Jerome P. ;

University of Michigan

关键词: Design of Bio-Inspired Mechanisms;    Mechanical Engineering;    Engineering;    Mechanical Engineering;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/84608/gikrishn_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Traditional engineering designs associate strength with rigidity. As a result, mostengineering systems that involve mechanical motion typically consist of rigid linksconnected with joints or interfaces. In contrast, nature achieves motion by exibilityor compliance through elastic deformation. It maintains strength by distributing compliancethroughout its geometry rather than localizing it. Incorporating distributedcompliance in engineering designs yield monolithic systems that are cost-effective,lightweight, having reduced peak stress, and zero friction and wear. The principles ofmechanics accurately predict the behavior of these compliant mechanisms, but yieldlittle insight into their systematic synthesis. This thesis proposes a mathematicalframework to represent problem specifcations and the mechanism behavior in termsof geometrically intuitive quantities that enable analysis and synthesis. Compliancerepresentation is proposed for (i) single port mechanisms with a unique point of interestin terms of geometric quantities such as ellipses and vectors, and (ii) multipleport mechanisms with transmission of load and motion between distinct input(s) andoutput(s) is captured in terms of load ow. This geometric representation provides a direct mapping between the mechanism geometry and their behavior, and is usedto characterize simple deformable members that form a library of building blocks.The design space spanned by the building block library guides the decomposition of agiven problem specification into tractable sub-problems that can be each solved froman entry in the library. The effectiveness of this geometric representation aids userinsight in design, and enables discovery of trends and guidelines to obtain practicalconceptual designs. Furthermore, the thesis proposes an optimization technique fordimensional synthesis of conceptual designs to uniformly distribute stresses throughoutits constituent members, thereby reducing peak stresses that lead to failure.The resulting metric used for renement enables an objective comparison and globalranking of various mechanism geometries and their actuation schemes based on theirability to store energy, or perform work before failure.The geometrically insightful conceptual synthesis methodology, optimization techniqueand global comparison of resulting designs furnish a pragmatic methodology forthe synthesis of distributed compliant mechanisms. This methodology is successfullyapplied to obtain solutions for some practical applications.