Salto jumping robot mimics the African bushbaby

The Biomimetic millisystems Lab at UC Berkeley is rather known for making small robots that mimic animals and so far Ron Fearing and his team have created some unique little robots. They have bots that can run, bots with wings, bots with tails, and hairy robots. The latest robot is a tiny thing that is hailed as the most agile robot ever made and it is designed to mimic a very cute animal that lives in Africa called the bushbaby or galago.

Other than being very cute, the bushbaby is most known for its diminutive size and ability to leap bushes that are nearly two meters tall in a single bound. The impressive jumping ability for the bushbaby comes from the structure of their legs that are able to amplify the power of their muscles and tendons. The robot that Fearing and his team designed is called Salto and uses a leg structure similar to what occurs naturally in the bushbaby.

That leg structure makes Salto the most agile legged jumping robot around. In this instance agility is defined as how far up the bot can jump over an over. The bushbaby for instance can jump 1.7m high every 0.78s giving it a measured agility of 2.2m/s. Salto isn't quite as agile as the animal it is based on able to jump 1.0m every 0.58 seconds for an agility of 1.7m/s.

Salto uses a spring, in this case rubber that can be twisted in series between the motor and the environment to create a series elastic actuator or SEA. The big benefit of the design is that the SEA helps protect the motor, allows force control, and allows for passive energy recovery and most importantly enables power modulation. Salto is able to wind the spring over a relatively long period of time and then release all that energy over a relatively short period of time. Salto takes advantage of a crouching action that is about 60ms more than doubling the length of time the bot is able to transfer energy to ground helping to to perform better.

SOURCE: Sciencemag