Optimizing Legged Locomotion Using Tunable Leg Stiffness

Running efficiently and successfully over unstructured terrain is an important and necessary characteristic for modern legged robots. Research suggests that a necessary step toward achieving this goal is to design legged robots with variable leg stiffness capabilities which can be controlled by the robot autonomously. The specific problem addressed in this research is to develop a wireless (infrared) tunable leg stiffness module that will change leg stiffness when commanded by the robot. In this research, a legged robot with six C-shape legs called RHex is used. The development of the tunable leg stiffness module had two phases. The first phase focused on the design of an infrared communication module that would allow each leg to communicate with the robot body. The second phase involved the integration of a motor and rotary sensor to accurately control stiffness of the leg based commands from robot. In this paper, we discuss the development of this novel tunable robot leg and highlight its advantages and limitations for optimizing RHex-like legged locomotion platforms.