Tiny Robot Gets Passive Dynamic Gait
Carnegie Mellon engineers have developed a new minimally actuated bipedal walking robot that's based on 3D passive dynamic walking.
With the technology available today, it’s easy to design a bipedal robot that mimics the way humans walk, or rather our gait. That’s because human-sized robots have enough internal space to fit a series of actuators and motors to drive the legs without issue. Scale those robots down to the size of Lego minifigures, and the space constraints become problematic, limiting the amount of hardware that can be packed into the legs of the tiny robot, which dramatically restricts its gait.
To help solve that problem, engineers from Carnegie Mellon University are developing a tiny 15-centimeter-tall bipedal robot capable of starting, stopping and turning using a single actuator. “By carefully studying the dynamics, designing the shape of the feet, and exploring the control space, we are able to achieve robust walking over a wide range of control amplitudes and frequencies,” the team states.
The design relies on passive 3D dynamics, which utilizes spherical feet and a total of five rigid bodies and a single actuator per leg. What’s more, the robot requires no feedback as an open-loop sinusoidal profile controls each leg
Regardless of the robot’s simplicity, the engineers successfully demonstrated three keys to its design ins simulations and physical experiments – stable walking over a range of actuation parameters, control over direction, and the ability to start and stop from a standing posture. To that end, the engineers are looking to incorporate and control the yaw of the bipedal robot with only two degrees of freedom and increase the level of control over the robot’s heading.