Distributed shape optimization of compliant mechanisms using intrinsic functions
Journal
Journal of Mechanical Design
Journal Volume
130
Journal Issue
7
Start Page
0723041
End Page
07230410
ISSN
10500472
Date Issued
2008
Author(s)
Cheng, Yungjen
Abstract
A compliant mechanism transmits motion and force by deformation of its flexible members. It has no relative moving parts and thus involves no wear, lubrication, noise, or backlash. Compliant mechanisms aim to maximize flexibility while maintaining sufficient stiffness so that satisfactory output motion may be achieved. When designing compliant mechanisms, the resulting shapes sometimes lead to rigid-body type linkages where compliance and rotation is lumped at a few flexural pivots. These flexural pivots are prone to stress concentration and thus limit compliant mechanisms to applications that only require small-deflected motion. To overcome this problem, a systematic design method is presented to synthesize the shape of a compliant mechanism so that compliance is distributed more uniformly over the mechanism. With a selected topology and load conditions, this method characterizes the free geometric shape of a compliant segment by its rotation and thickness functions. These two are referred as intrinsic functions and they describe the shape continuously within the segment so there is no abrupt change in geometry. Optimization problems can be conveniently formulated with cusps and intersecting loops naturally circumvented. To facilitate the optimization process, a numerical algorithm based on the generalized shooting method will be presented to solve for the deflected shape. Illustrative examples will demonstrate that through the proposed design method, compliant mechanisms with distributed compliance will lessen stress concentration so they are more robust and have a larger deflected range. It is expected that the method can be applied to design compliant mechanisms for a wide variety of applications.
Subjects
Compliant Mechanisms
Distributed Compliance
Shape Optimization
Shooting Method
Design
Mechanisms
Numerical Methods
Shape Optimization
Stress Concentration
Distributed Compliances
Intrinsic Functions
Load Condition
Lubrication /
Moving Parts
Output Motion
Rigid Body
Shape-optimization
Shooting Methods
Systematic Design Methods
Compliant Mechanisms
Publisher
American Society of Mechanical Engineers(ASME)
Type
journal article