Meet Zippy, the Smallest Bipedal Robot
Carnegie Mellon’s College of Engineering has unveiled Zippy, the world’s smallest fully autonomous bipedal robot. Standing just 3.6 cm tall and weighing around 25 g, Zippy carries its own battery, single actuator, and control electronics—making it a fully self-contained system.
“In a world designed for humans, two-legged robots are able to navigate uneven terrains and maneuver around objects more easily than robots with wheels,” explained Aaron Johnson , a professor of mechanical engineeringOpens in new window. “For this reason, we have been investigating how to eliminate complex walking mechanisms to make simple, two-legged robots possible.”
Transcript
00:00:06 Steven: So this is Zippy, the smallest bipedal robot. Zippy is pretty short. It's about three centimeters tall with a leg length about 2.5 centimeters. And it's also self-contained, meaning that all the controls, power, motor is all on board and is able to operate autonomously. In this project, we're trying to study how locomotion scales as you move up and down. In this case, when you go smaller, what changes in terms of how difficult it is to control. And with this robot, it's actually able to go at 25 centimeters a second. It's not quite that fast, but when you compare how small this robot is, it's about 10 leg lengths per second, which is the fastest out of all the bipedal robots. For these larger robots like humanoids, we have to have very precise motor control to make sure that the robot is doing exactly what the programmer tells it to do. At the smaller scale,
00:00:49 this becomes harder and harder to do because the actuators and sensors become noisier and noisier. So to solve this problem, we use hardware to mechanically feed back in the system, where the hard stop actually doubles as both a joint limit for the hip as well as mechanically feed back to regulate the leg speed. Josef: So Zippy has one motor along its hip axis and it's controlled by a hard stop. So as one leg swings by the motor, it reaches the hard stop, which allows the other leg to kind of lean forward and swing forward as it walks. Soma: Another thing about Zippy is that it has rounded feet, which allows it to sway sideways and rock back and forth. And the weight on the arm allows it to sway sideways a lot more so that it can lift its feet up to swing back and forth.
00:01:34 Steven: So far we look at the locomotion characteristics of the robot and we believe the next step is to add more sensors to it, such as the inertial measurement unit as well as a camera so it's able to localize and autonomously navigate its environments. Small robots are important because they can go into tighter spaces and go on rougher terrain than wheel robots at that size. These situations usually occur in industrial inspection, disaster search and rescue, as well as geologically interesting areas where we do scientific research. I think this robot also has an educational impact in that this allows students to explore the concepts of leg locomotion as well as mechanism design, hopefully inspiring them to design fun robots just like this one.