BLUE: A 3D Dynamic Bipedal Robot

Abstract: The objective of this work is to design a mechatronic bipedal robot with mobility in 3D environments. The designed robot has a total of six actuated degrees of freedom (DoF), each leg has two DoF located at the hip: one for abduction/adduction and another for thigh flexion/extension, and a third DoF at the knee for the shin flexion/extension. This robot is designed with point-feet legs to achieve a dynamic underactuated walking. Each actuator in the robot includes a DC gear motor, an encoder for position measurement, a flexible joint to form a series flexible actuator, and a feedback controller to ensure trajectory tracking. In order to reduce the total mass of the robot, the shin is designed using topology optimization. The resulting design is fabricated using 3D printed parts, which allows to get a robot's prototype to validate the selection of actuators. The preliminary experiments confirm the robot's ability to maintain a stand-up position and let us drawn future works in dynamic control and trajectory generation for periodic stable walking.