Research Highlights - Human-Centered Robotics Group at UT Austin

Thermal Recovery of Actuators in Legged Robots

We know that our legs get jammed if we keep them in a single position for a long time. A similar situation occurs for humanoids too. For example, if some actuators of humanoids are at high stress for a long duration, the active actuators generate a lot of heat in that posture. The Human-Centered Robotics Group under professor Luis Sentis at UT Austin has developed an ingenious solution to this issue by predicting the temperature of actuators from the history of force inputs. And they are using that inputs to plan the thermal recovery of multi-limber robots with electric actuators.

So, with this model, they have implemented a control strategy for a humanoid robot from NASA- Valkyrie. Given a task to stand on a single leg, it stands on the left leg for some time. When it receives input from the predictive model of high thermal load on left leg actuators, it switches to stand on the right leg. It transitions to the two-legged standing posture when the right leg actuator temperatures also cross the threshold. This process helps actuators to recover thermally as our muscles also recover after high-stress activities.

Ball-screw based High-Performance Series Elastic Actuators