Landing method for a one-legged robot with artificial muscles and an MR brake

Bipedal robots capable of various dynamic motions - such as walking, running, and jumping - have been developed in recent years. In particular, these dynamic motions require high power for short durations of time when the robot kicks off the ground. Furthermore, it is necessary to reduce the impact force that a robot is subjected to when landing during these motions. When humans perform similar motions, they generate an instantaneous high-power force using an elastic element and dampen the impact force using a viscous element in their muscles. Therefore, a robotic leg designed for jumping that relies on these elements has been developed. It uses a straight-fiber-type artificial muscle and a magnetorheological (MR) brake. A previously designed one-legged robot was able to jump 82.5 mm using a sliding rail and counter weights; however, it shook upon landing due to an elastic element in its artificial muscles. Here, therefore, an MR brake to dissipate energy is applied to the robotic leg in order to suppress vibration. Landing experiments performed with the newly designed one-legged robot confirm that the proposed method (i.e., using the MR brake) is able to suppress vibrations.