Under-Actuated Humanoid Model With Elastomeric Springs
This paper presents the mechanical modifications and simulation of a bipedal humanoid system actuated with linear springs to produce a standing equilibrium position. The original humanoid system is comprised of two leg assemblies connected by a hip bracket. Eleven pairs of springs were attached to the system in locations designed to simulate the muscles and tendons in a human body. The next evolution of the LUIGEE project is the inclusion of three servo motors per leg and a series of elastomeric springs. Although servo motors have been introduced, it is desired to maintain the passive, static aspect of the previous prototype. This paper reports on part modifications to accommodate servo motors and the introduction of polymeric springs that guarantee static stability. ABS plastic and photopolymer resin was used to produce the new model. Due to the size of the motors, some parts of the original robot were redesigned. The new design iteration was stimulated using SimWise 4D®, where the hysteretic effect of rubber was modelled with an equivalent viscous damping.