Sangju: A quadrupedal walking robot developed by a South Korean university has successfully completed a full-course marathon. The Korea Advanced Institute of Science and Technology (KAIST) announced that the robot, named Raibo 2, accomplished this groundbreaking feat, marking the first time such an achievement has been recorded globally. Raibo 2 finished the 42.195-kilometer Sangju Gotgam Marathon in four hours, 19 minutes, and 52 seconds, showcasing its endurance and advanced capabilities. According to Yonhap News Agency, Raibo 2 was developed by a team at KAIST led by professor Hwangbo Je-min. The robot can walk continuously for 43 kilometers on a single charge, surpassing the previous record of 20 kilometers by existing quadruped walking robots. The marathon course in Sangju is notably challenging for amateur marathoners due to two significant elevation climbs of 50 meters at the 14-kilometer and 28-kilometer marks. Walking robots like Raibo 2 are based on intricate systems designed to withstand vibratio ns from frequent ground impacts. To enhance Raibo 2's performance, the KAIST team integrated the motor driver circuitry directly into the robot, minimizing actuator losses and increasing control bandwidth for improved walking efficiency and stability. They also developed a controller to ensure stable walking performance. A high-torque joint mechanism is a key feature of Raibo 2, allowing it to efficiently harvest energy on downhill slopes, which aids in climbing steep hills. This innovation significantly contributes to the robot's energy efficiency and performance, as explained by KAIST. Ph.D. student Lee Choong-in from KAIST remarked, "Through the marathon project, Raibo 2 demonstrated it can stably execute services, such as delivery and patrol, in urban surroundings." He further noted that follow-up research would focus on adding autonomous navigation functions to the robot to enhance its walking performance in mountainous and disaster environments.