Steve Buerger leads the Sandia project to demonstrate how energy-efficient biped walking robots could become. (Photo by Randy Montoya)

Sandia National Laboratories is developing technology that will dramatically improve the endurance of legged robots, helping them operate for long periods while performing the types of locomotion most relevant to disaster response scenarios. One area of focus is battery life – an important concern in the usefulness of robots for emergency response.

The first robot Sandia is developing is a fully functional research platform that allows developers to try different joint-level mechanisms that function like elbows and knees to quantify how much energy is used. The key to the testing is Sandia’s novel, energy-efficient actuators, which move the robots’ joints. The actuation system uses efficient, brushless DC motors with very high torque-to-weight ratios, very efficient low-ratio transmissions, and specially designed passive mechanisms customized for each joint to ensure energy efficiency.

Electric motors are particularly inefficient when providing large torques at low to a crouching robot. A simple support element, such as a spring, would provide torque, reducing the load on the motor.