American Journal of Applied Sciences 4 (3): 160-167, 2007 ISSN 1546-9239 © 2007 Science Publications, Corresponding Author: Solehuddin Shuib, School of Mechanical Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal, Seberang Perai, Penang, Malaysia 160 Methodology of Compliant Mechanisms and its Current Developments in Applications: A Review 1 Solehuddin Shuib, 1 M.I.Z. Ridzwan and 2 A Halim Kadarman 1 School of Mechanical Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal Seberang Perai, Penang, Malaysia 2 School of Aerospace Engineering, Universiti Sains Malaysia, 14300 Nibong Tebal Seberang Perai, Penang, Malaysia Abstract: Traditional rigid-body mechanisms consist of a number of components to implement their functions. Therefore they face problems such as backlash, wear, increase in part-count, weight, assembly cost and time, regular maintenance. Reducing these problems will help in increasing mechanism performance and cost reduction. Recently, there are several examples of compliant mechanisms that have been designed and widely used in various fields such as for adaptive structures, biomedical, hand-held tools, components in transportations, MEMS and robotics. However, the largest challenge was relative difficulty in analyzing and designing compliant mechanisms. Two approaches known in the literature for the systematic synthesis of compliant mechanisms are the kinematics-based approach and the structural optimisation based approach. Key words: Compliant mechanisms, rigid-body mechanisms, kinematics and structural optimisation based approach INTRODUCTION A compliant mechanism can be defined as single- piece flexible structure, which uses elastic deformation to achieve force and motion transmission [1,2] . It gains some or all of its motion from the relativeflexibility of its members rather than from rigid body joints alone [3] . Such mechanism, with built-in flexible segments, is simpler and replaces multiple rigid parts, pin joints and add-on springs. Hence, it can often save space and reduce costs of parts, materials and assembly labor. Other possible benefits of designing compliance into devices may be reductions in weight, friction, noise, wear, backlash and importantly, maintenance. There are many familiar examples of compliant mechanisms designed in single-piece that replaced rigid-link mechanisms, which will be highlighted in other section in this study. Figure 1, shows examples of compliant mechanisms used commonly. We can simply manufacture a single-piece fully compliant mechanism via injection molding, extrusion and rapid prototyping for medium size devices [4] , or using silicon surface micromachining [5] and electroplating techniques [6] for compliant micromechanisms. Although a compliant mechanism gives numerous advantages, it is difficult to design and analyze. Much of the current compliant mechanism design, however, must be performed without the aid of a formal synthesis method and is based on designer’s intuition and experience [7-9] . Several trial and error iterations using finite element models are often required to obtain the desired mechanism performance. Typically, there are two approaches known in the literature for the systematic syntheses of compliant mechanisms are the kinematics based approach [10] and the structural optimization based approach [11-14] . Fig. 1: Common compliant devices. A binder clip, paper clip, backpack latch, lid, eyelash curler and nail clippers are shown [3]