Disney researchers have built a two- legged robot that mimics both the looks and movements of an animated character.
Beginning with an animation of a diminutive, peanut-shaped character that walks with a rolling, somewhat bow-legged gait, Katsu Yamane and his team at Disney Research Pittsburgh analyzed the character’s motion to design a robotic frame that could duplicate the walking motion using 3D-printed links and servo motors, while also fitting inside the character’s skin. They then created control software that could keep the robot balanced while duplicating the character’s gait as closely as possible.
Yamane, senior research scientist said that the biggest challenge was that designers generally didn’t consider physics when they create an animated character. Roboticists, however, wrestle with physical constraints throughout the process of creating a real-life version of the character.
By studying the dynamics of the walking motion in simulation, the researchers realized they could mimic the motion by building a leg with a hip joint that has three degrees of freedom, a knee joint with a single degree of freedom and an ankle with two degrees of freedom.
Because the joints of the robot differ from what the analysis showed that the animated character had, the researchers couldn’t duplicate the character’s joint movements, but identified the position trajectories of the character’s pelvis, hips, knees, ankle and toes that the robot would need to duplicate. To keep the robot from falling, the researchers altered the motion, such as by keeping the character’s stance foot flat on the ground.
They then optimized the trajectories to minimize any deviation from the target motions, while ensuring that the robot was stable.
The techniques and technologies used to create the bipedal robot will be presented at the IEEE International Conference on Robotics and Automation, ICRA 2015.