KAIST's 4-legged robot becomes 1st in the world to finish full marathon

Lee Choong-in, left, a doctorate student at the Korea Advanced Institute of Science & Technology (KAIST), poses with the RAIBO 2 team after the robot completed a 42.195-kilometer course at the 22nd Sangju Marathon in North Gyeongsang Province, Sunday. Courtesy of KAIST By Nam Hyun-woo RAIBO 2, developed by a research team from the Korea Advanced Institute of Science & Technology (KAIST), has become the first four-legged robot in the world to finish a full marathon, showcasing its walking control technology and durability.

According to the university, RAIBO 2 participated in the 22nd Sangju Marathon in the North Gyeongsang Province city on Sunday, completing the 42.195-kilometer course in four hours, 19 minutes and 52 seconds, on a single battery charge. The course includes two 50-meter-high hills at the 14-km and 28-km marks, making it a challenging route for runners and for quadruped robots due to unexpected obstacles.



The team, led by professor Hwangbo Je-min and doctorate student Lee Choong-in, used an advanced learning algorithm for RAIBO 2, allowing it to train its walking mechanism in Raisim, an environmental simulation designed by Hwangbo to replicate diverse terrains such as slopes, stairs and icy paths. Quadruped robots are demonstrating excellent mobility across challenging terrains, expanding their use in fields such as surveillance and reconnaissance. However, compared to wheeled robots, they have shorter operating ranges and times due to energy demands for supporting their weight and the energy loss from intermittent ground contact during walking, according to the team.

The team noted that improving energy efficiency by reducing energy consumption per distance traveled is the key to longer operating ranges. RAIBO 2 used an advanced joint mechanism to recharge while descending slopes, and partially offset the energy used while climbing. The team said Raion Robotics, a company established by Hwangbo, took charge of manufacturing and played a pivotal role in the project, allowing the team to independently engineer all aspects of the project, including mechanical design, electrical systems, software and artificial intelligence.

“With the marathon project, we demonstrated that RAIBO 2 possesses walking capabilities stable enough to perform services like delivery and patrol in urban environments,” Lee said. “Our future research will focus on integrating autonomous driving features into RAIBO, aiming to achieve world-best walking performance even in mountainous and disaster environments.”.