Ph.D. Student Gets the Assist as Bike Robot Performs First Front Flip

A bicycle robot from the Robotics and AI Institute (RAI) in Cambridge, Mass., has become the first to perform an unassisted acrobatic front flip.

RAI calls the bicycle robot an ultra-mobility vehicle (UMV). It can reach a height of 3 feet and can jump from the floor onto a platform.

The contributions of a Georgia Tech Ph.D. student helped make these feats possible through a robot control policy he developed.

Jeonghwan Kim, who is pursuing a Ph.D. in robotics under the advisement of Associate Professor Sehoon Ha, spent two semesters interning at RAI. His task was to design a policy to teach the UMV to land after a flip.

The result was iterative motion imitation (IMI), a novel method that imitates flip trajectories generated from prior examples. Kim said the robot bases its flip on a demonstration, and human engineers reconstruct and refine the flip path through simulation to fill in the gaps.

“To guide the robot to flip, we started with an imperfect trajectory generated by a motor-based controller and then ran simulations,” Kim said. “It’s an unstable trajectory, but we use it as a guide to train a single policy that can track it as it lands and tries to balance itself.”