Classification of Compliant Mechanisms and Determination of the Degrees of Freedom using the Concepts of Compliance Number and Pseudo-Rigid-Body Model


Understanding the kinematic properties of a compliant mechanism has always proved to be a challenge. A concept of compliance number offered earlier emphasized the development of terminology that aided in its determination. A method to evaluate the elastic degrees of freedom associated with the flexible segments/links of a compliant mechanism using the pseudo-rigid-body model (PRBM) concept is provided. In this process, two distinct classes of compliant mechanisms are developed involving: (i) Active Compliance and (ii) Passive Compliance. Furthermore, these also aid in a better characterization of the kinematic behavior of a compliant mechanism. A more lucid interpretation of the significance of compliance number is provided. Applications of this method to both active and passive compliant mechanisms are exemplified. Finally, an experimental procedure that aids in visualizing the degrees of freedom as calculated is presented.

Meeting Name

ASME 2019 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC-CIE 2019 (2019: Aug. 18-21, Anaheim, CA)


Mechanical and Aerospace Engineering


The authors are grateful for the support offered by Missouri University of Science and Technology and the Product Innovation and Creativity Center (PICC) at S&T.

Keywords and Phrases

Compliant mechanisms; Design; Kinematics; Mechanisms; Rigid structures, Active compliance; Experimental procedure; Flexible segments; Kinematic behaviors; Kinematic properties; Passive compliance; Pseudo-rigid-body models, Degrees of freedom (mechanics)

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


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© 2019 American Society of Mechanical Engineers (ASME), All rights reserved.

Publication Date

01 Aug 2019