SuperLimbs, the robot that helps astronauts stand up after a fall

Compared with the Earth, the lunar environment poses many constraints and challenges to human activities.

"Astronauts' bodies are very capable, but they can struggle on the moon, where gravity is one-sixth of that on Earth, but their inertia is still the same. Also, wearing a spacesuit is a heavy burden that restricts their movement," said Harry Asada, a professor of mechanical engineering at MIT. "We wanted to provide astronauts with a safe way to get back up if they fall."

In order to help astronauts reduce the physical burden when performing lunar missions and respond quickly and provide assistance when they fall, Professor Harry Asada of MIT and his team developed this "SuperLimbs" robot system. Its core design concept is to equip astronauts with a pair of wearable robotic arms, just like a pair of "super limbs", to assist astronauts in completing various operations.

The pair of robotic arms are mounted on a large backpack carried by the astronauts, which also integrates the control system, power system and life support equipment for the astronauts. The robotic arms are designed with multiple joints and can be extended and retracted as needed. When the astronauts are performing tasks, the pair of robotic arms can provide support for the astronauts or assist in completing certain operations, just like human arms. When the astronauts accidentally fall, the control system can accurately predict and simulate the process of the human body naturally restoring its center of gravity, and then command the robotic arms to orderly lift the astronauts up and help them return to an upright position.

The researchers have built a physical prototype and tested a preliminary version on healthy subjects who also volunteered to wear a bodysuit similar to an astronaut's spacesuit. When the volunteers tried to stand up from a sitting or lying position, using SuperLimbs required much less effort.

Based on the large amount of data obtained, they designed a set of control algorithms to guide the robot arm to assist astronauts in different scenarios. At the same time, for hardware design, the research team also used optimization search and other means to seek a mechanism form that minimizes energy consumption and maximizes the recovery of the human body's center of gravity while meeting engineering constraints.

It is reported that the team will build the complete SuperLimbs system at NASA's Jet Propulsion Laboratory this summer, where they plan to simplify the design and use advanced lightweight materials to minimize the weight of its parts and motors, pair the limbs with astronaut suits, and test them in low-gravity simulators, with the goal of one day assisting astronauts in future lunar and Mars missions.