ETH Zurich: Four-legged ANYmal robot plays badminton

A team of engineers at the Swiss Federal Institute of Technology in Zurich (ETH Zurich) has developed a four-legged ANYmal robot that can play badminton with a human. The researchers are using reinforcement learning to enable the robot, called ANYmal-D, to track the shuttlecock and make predictions about its flight.

Badminton is a fast game that requires fast shuttlecock recognition, trajectory prediction and skillful racket control and footwork. This is the only way to hit the ball over the net to the desired position in the court to outwit the opponent.

The researchers used an existing ANYmal robot, which was developed at the ETH Zurich and expanded for the game of badminton, as can be seen from the study "Learning coordinated badminton skills for legged manipulators", which was published in Science Robotics. The researchers equipped the robot with a stereo camera and a dynamic robotic arm that has several joints and can move the badminton racket into all positions.

The robot's leg and stroke movements are controlled and coordinated by a controller based on reinforcement learning. The scientists implemented a "perception noise model" for this purpose. A model that compares the live data supplied by the stereo camera with a training database that was previously created using virtual simulations.

A quick-witted robot

This enables the robot to perform human-like badminton strokes and movements. This not only includes correct stroke control, but also movements such as tilting the robot's body in order to better track the trajectory of the shuttlecock with the camera.

The researchers tested the robot in practice playing badminton with humans. The robot was able to return the shuttlecock from many positions. According to the ETH scientists, up to ten consecutive strokes could be performed.

(olb)