INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND MANUFACTURING Vol. 12, No. 3, pp. 565-568 JUNE 2011 / 565 DOI: 10.1007/s12541-011-0071-2 1. Introduction Shape memory alloys (SMAs) provide functional properties associated with the shape memory effect (SME), which was firstly observed in early 1960s. One of the major advantages of SMAs over other actuator materials is the large recovery force generated by a phase transformation following initial deformation. 1 The generated force per unit area is remarkably high, typically more than 10 times that of traditional electrohydraulic, servomechanical actuators (21–35 MPa), high output exciting actuators for vibration control, and laminated PZT (lead zirconate titanate) actuators (35 MPa). 2 Over the past 10 years, this effect has often been exploited in the form of embedding SMA wire and thin film actuators into a variety of host materials. 3-8 In particular, many clinical biomedical devices have been developed using SMA, 4 including pumps, grippers, 5 and sealing devices. 6 Recently SMAs were used in many robot actuators because of their high energy density. 7,8 By using an SMA spring as an actuator in a wireless earthworm-like robot, it is possible to mimic the repeated movements of contraction and expansion. 9 Wang et al. used SMA wire in rubber/silicone to develop radio frequency- controlled micro fish robot with fin movements resembling those of a squid or cuttlefish. 10 These pioneer researches illustrate various practical applications of the properties of SMA. In this study, an inchworm robot was fabricated using a SMA embedded in composite material. A wire SMA was embedded into an ∩-shaped glass fiber reinforced polymer (GFRP) strip. The SMA composite inchworm robot was actuated by varying the radius of curvature in accordance with the applied power. This technique is possible to give repeated movement by applying power. To give directional movement, the legs were attached to both ends of robot body with two different friction coefficients. This technique does not need motors or gears which are the traditional components for the moving mechanism, and can be applied to the soft robot actuators, bio medical devices, airplane inlet, 11 etc. 2. Design of the inchworm robot 2.1 Body and legs Schematic diagram of the inchworm robot with unidirectional movement is shown in Fig. 1. The robot is constructed of GFRP composite, with a single SMA wire embedded in the composite as an actuator. The main body and the actuator are mechanically fastened by bolts and nuts. 11 The synthetic rubber legs are located at Manufacturing of Inchworm Robot Using Shape Memory Alloy (SMA) Embedded Composite Structure Min-Saeng Kim 1 , Won-Shik Chu 1,* , Jae-Hoon Lee 1 , Y un-Mi Kim 1 and Sung-Hoon Ahn 1,# 1 School of Mechanical and Aerospace Engineering, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul, Korea, 151-142 * Current Position: Harvard-MIT Division of Health Sciences and Technology, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, PRB-252, 65 Landsdowne Street, Cambridge, MA, USA, 02139 # Corresponding Author / E-mail: ahnsh@snu.ac.kr , TEL: + 82-2-880-7110, FAX: + 82-2-883-0179 KEYWORDS: Shape memory alloy, Composite, Inchworm, Robot To design effective movement of robots, various locomotive mechanisms have been investigated. In this study, an inchworm robot was manufactured using shape memory alloy (SMA) which was embedded in composite materials. A Ni-Ti SMA wire was pre-strained and embedded in the glass fiber reinforced polymer (GFRP) strip laid on an ∩-shape mold. Then SMA embedded composite structure was cured at room temperature for 72 hours. Controlling DC current through the SMA wire, the SMA-composite structure, body, could be actuated by changing the radius of curvature. Two legs were attached to the end of body and the leg has two edges which have different coefficients of friction to provide directional movement. One stroke of inchworm provided 4.0 mm translational movement. Repeating on and off of DC current, the inchworm robot gives continuous movement. This mechanism can be applied to the soft morphing robotics, bio medical devices, airplane inlet, etc. instead of using traditional components for their movement. Manuscript received: July 1, 2010 / Accepted: December 16, 2010 © KSPE and Springer 2011