Engineers develop deft solution to orient robots in space

UC College of Engineering and Applied Science graduate student James Talavage and Professor Ou Ma looked at simple but effective ways for a robot to maintain orientation while working on a broken satellite in zero gravity.

And just as a bull rider uses a free arm for balance, the aerospace engineers found that inertia generated by a second robotic arm kept both the robot and the satellite stable in simulations of in-space service, assembly and manufacturing.

Talavage and Ma call the system Dual-Arm Zero Momentum, which minimizes the attitude disturbance to the vehicle being repaired by maneuvering one arm while the other performs repairs. Just as a bull rider will use one arm to maintain balance, the robot uses an arm autonomously to correct any yaw, pitch or roll fluctuations caused by its interaction with the satellite.

Ma said making contact with a satellite is a tricky part of the operation. A slight bump can send both satellite and robot careening wildly in different directions.

“Physical contact is always the most difficult and critical part. Physical interactions can cause damage and make the satellite unstable,” Ma said.

They presented their simulation at the American Institute for Aeronautics and Astronautics’ SciTech Forum conference in Orlando, Florida, this year. The research is supported with grants from the U.S. Space Force.

“I think it’s a very practical solution with the current hardware that we have and the typical conditions for servicing satellites,” Talavage said.

Ma said the robot responds much like a person does while learning how to ice-skate.

“Think about standing on the slippery ice. If I ask you to grab something with one arm, I’m sure you’ll use the other arm to balance yourself. It’s unconscious. You do it naturally,” Ma said.

“Our idea is if you have another arm not doing anything, why not use it to make intentional movements to cancel out reactions for balance?”