DESIGN OF A LOW-COST TUNABLE STIFFNESS ROBOTIC LEG BASED ON A CIRCULAR ARCH MECHANISM

Abstract

Recent development of legged robots has focused on improving their motion performance by introducing tunable stiffness in the leg structure. In this work, an R-SLIP model of the robotic arc leg is developed for studying the influence of leg stiffness on its gait stability. Then, a novel tunable stiffness arc leg having a large and repeatable stiffness range is designed based on a circular arch mechanism. This paper also presents the driving mechanism and control strategy for the tunable stiffness leg. A key advantage of this design is that the driving mechanism for stiffness tuning shares the same motor with the device for driving the leg motion. The experimental result demonstrates the tunable stiffness capability for this low-cost leg design.