Simple and low-cost compliant leg-foot system

We describe a simple and low-cost humanoid leg design with compliant joints and springy feet. Mechanical compliance is achieved by combining visco-elastic material with metal. Joints and feet characteristics are evaluated by repeatedly dropping the system from a fixed height. Different joint configurations (silicone rubber, latex and brass) and foot compliance are examined, and additional data are obtained with a Lagrangian analysis of the system. We show that compliance not only reduces impact forces, but also induces smoother joint trajectories.