Mechanical Advantage of a Compliant Mechanism and Significant Factors Affecting IT, Using the Pseudo-Rigid-Body Model Approach


Although work related to mechanical advantage of compliant mechanisms has been presented almost two decades ago, unlike many rigid-body mechanism systems, this performance measure has seldom been used. In great part, the reasons are attributed to, one, the relatively recent development of and a lack of familiarity with this technology and, two, the complexity of the understanding and evaluation of mechanical advantage of compliant systems. In an effort to simplify the evaluation, this work uses the pseudo-rigid-body model (PRBM) of a compliant mechanism, along with traditional notions of power conservation and angular velocity ratios using instant centers. As a first step, the inherent compliance in the mechanism is neglected in determining its mechanical advantage, followed by considerations to optimize its structural configuration for enhancing its mechanical advantage. The PRBM methodology, which offers us a way to estimate the characteristic compliance of the mechanism, now enables its inclusion in determining the mechanical advantage of the compliant mechanism. Two significant factors affecting it are i) the structural configuration of the PRBM, and ii) the energy stored in compliant elements of the mechanism. Several case studies are presented, which suggest that minimizing the latter contribution relative to that of an optimized structural configuration may improve the mechanical advantage of a compliant mechanism. Nonetheless, its effect on the mechanical advantage cannot be neglected.

Meeting Name

ASME 2015 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference, IDETC/CIE 2015 (2015: Aug. 2-5, Boston, MA)


Mechanical and Aerospace Engineering

Keywords and Phrases

Compliant mechanisms; Design; Rigid structures; Case-studies; Instant center; Mechanical advantage; Mechanism systems; Performance measure; Power conservation; Pseudo-rigid-body models; Structural configurations; Mechanisms

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


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© 2015 American Society of Mechanical Engineers (ASME), All rights reserved.

Publication Date

01 Aug 2015