We have completed maintenance on DiscoverMagazine.com and action may be required on your account. Learn More

Building a Better Jumping Robot

Physicists find the secret to more efficient hopping.

By Gregory Mone
Apr 8, 2013 8:00 PMNov 14, 2019 10:12 PM
Georgia Tech physicist Daniel Goldman (left) and graduate student Jeffrey Aguilar examine a simple robot built to study the dynamics of jumping. They may have found the secret to more efficient hopping. | Gary Meek/Georgia Tech


Sign up for our email newsletter for the latest science news

The world has no shortage of great leapers, from hopping kangaroos to high-jumping basketball stars. But according to physicist Daniel Goldman of Georgia Tech, the seemingly simple act of bouncing remains a rich source of research questions. In hopes of designing hopping robots, Goldman and his colleagues first set out to study the physics of bouncing, and in the process they stumbled upon the secret to more effective jumps.

To start, mechanical engineering grad student Jeffrey Aguilar built a simple hopping robot. The device consists of an 8-inch-tall rod with a spring at its base. A motor, which is connected to a computer, moves vertically along the rod. When it travels up, the rod shifts down, compressing the spring. This causes the spring to recoil, thrusting it up off a platform. 

Aguilar wrote a program that randomly put the robot through nearly 21,000 different jumps. Each time, the motor’s starting position, its speed and more changed, and the scientists recorded each leap. After sifting through the data, they discovered the robot jumped to the same peak height using two very different techniques.

Click on the image to try this working model. | Georgia Tech

The first involved moving the motor rapidly, which sent more power into the spring. In another variation, the robot started with a small hop, then soared to the same height on its follow-up. This stutter jump, Goldman notes, could potentially conserve energy, requiring 10 times less power. 

Goldman suspects that well-known leapers might already take advantage of this energy-saving stutter. After identifying the trick, the group analyzed the 2008 commercial on YouTube of basketball star Kobe Bryant appearing to leap over a moving car. When they looked closely, they noticed that he stutter-hops just before his jump.

1 free article left
Want More? Get unlimited access for as low as $1.99/month

Already a subscriber?

Register or Log In

1 free articleSubscribe
Discover Magazine Logo
Want more?

Keep reading for as low as $1.99!


Already a subscriber?

Register or Log In

More From Discover
Recommendations From Our Store
Shop Now
Stay Curious
Our List

Sign up for our weekly science updates.

To The Magazine

Save up to 40% off the cover price when you subscribe to Discover magazine.

Copyright © 2024 Kalmbach Media Co.