In this study, we used shape memory alloys as actuators to build a biomorphic robot which can imitate the motion of an earthworm. The robot can be used to explore in a narrow space. Therefore we chose shape memory alloys as actuators. Because of the small deformation of a wire shape memory alloy, spiral shape memory alloys are selected and installed both on the X axis and Y axis (each axis having two shape memory alloys) to enable the biomorphic robot to do reciprocating motion. By the mechanism we designed, the robot can increase the distance as it moves in a duty cycle. In addition, two shape memory alloys are added to the robot head for controlling right and left turns. By sending pulses through the I/O card from the controller, the signals are then amplified by a driver to heat the shape memory alloys in order to make the SMA shrink to pull the mechanism to move.

{"references": ["B. Kim, M. G. Lee, Y .P. Lee, Y. Kim, and G. H. Lee, \"An earthworm-like\nmicro robot using shape memory alloy actuator,\" Sensors and Actuators A:\nPhysical, vol. 125, pp. 429-437, Jan. 2006.", "A. Menciassic, S. Gorini, G. Pernorio, and P. Dairo, \"A SMA actuated\nartificial earthworm,\" IEEE International Conference on Robotics and\nAutomation, New Orleans, USA, 2004", "Tanaka, \"A thermomechanical sketch of shape memory effect:\none-dimensional tensile behavior,\" Res mech, vol. 18, pp. .251-63, 1986.", "Kai-Chi Shiu, Dynamic Analysis & Motion Control of A Bio-mimic\nRobot, Master Thesis, National Taiwan University, Taipei, 2005."]}