This study aims to develop a quadruped-wheeled robot, MELEW-3 (Meiji Leg-Wheeled Robot - No. 3), combining the advantages of legged and wheeled robots. The leg mechanism is a four degrees of freedom (DoF) parallel link mechanism with spherical links. It enables the robot to move its leg tips in three translational directions (forward/backward, left/right, and up/down) and rotate around its vertical axis. In addition, the leg tips have an active wheel that provides 5-DoFs per leg and 20-DoFs for the robot. Since the steering angle of the wheels can be controlled, MELEW-3, unlike other quadruped-wheeled robots, can perform smooth-wheeled locomotion such as slalom running when moving on its wheels. The size of the robot is 500 mm (width) x 690 mm (length) x 580 mm (height), and its mass is 28 kg without the battery. Through evaluation experiments, we confirmed the basic performance of the robot by achieving wheel running with rapid acceleration and deceleration, slalom running to avoid obstacles while moving on its wheels, and forward movement with coordinated leg and wheel movement.
