On the Desing and Test of a Prototype of Biped Actuated by Shape Memory Alloys

Abstract

In this paper the design of a biped robot actuated with Shape Memory Alloy (SMA) springs with minimum degrees of freedom is presented. SMA springs are a class of smart materials that are known for their high power to mass and volume ratios. It was shown that utilizing spring type of SMAs have many advantages as large deformation, smooth motion, silent and clean movement compared to ordinary type of actuators. In this work a Biped robot actuated through SMA springs with four DOFs is modeled and designed. Walking trajectory is generated validating the Zero Moment Point (ZMP) Criteria and the number of DOFs is modified accordingly. To verify the design, a complete model of the biped actuated with SMA is modeled through computer simulation in MATLAB and Visual Nastaran. Finally to validate the results, a prototype is manufactured and tested. Experimental results showed reasonable agreement with simulation results.