Here’s the happiest robot I’ve seen this year! And it’s super efficient, using energy from one hop to power the next.
Festo’s BionicKangaroo recovers the energy when jumping, stores it, and then uses it for the next jump. Elastic springs in each leg stores energy on landing -- just like the tendon in a real kangaroo’s leg -- converting the kinetic (motion) energy of the jump into potential energy. Real kangaroos depend on that ability to store and reuse energy from each landing to hop long distances in the wild -- they’re the only large animals we know of that uses hopping as their primary means of locomotion.
Every year, the Germany-based company comes up with new robots as part of its Bionic Learning Network. The company actually spent two years analyzing kangaroos to recreate its movements. They're not aiming to build a kangaroo robot army; rather, they’re interested in exploring ways of recovering energy in industrial automation, IEEE Spectrum reports, and new ways of combining electronics with pneumatics (technology that’s powered by air or gas under pressure). Some more details about the BionicKangaroo:
It weighs about 15 pounds and stands about 3 feet tall. The main body is a shell made of foam.
Each leap lifts it just over a foot into the air and propels it about 2.5 feet forward.
A Thalmic Labs Myo armband lets you control it by gesturing with your arm.
Either a small compressor or a storage tank can be placed in the body to provide the high-pressure air for the pneumatic muscles that power the legs for jumping.
The knee and ankle joint are connected via a “positive kinematic device” that results in an interlinked movement sequence.
Rubber elastic springs are fastened at the back of the foot, parallel to the pneumatic cylinder on the knee joint. This artificial tendon cushions the jump, and simultaneously absorbs the kinetic energy and releases it for the next jump.
The electrical energy storage devices are lightweight, lithium polymer rechargeable batteries.
An elaborate control system using real-time diagnostics keeps the robot from toppling over.
Before the first jump, the BionicKangaroo shifts its center of gravity, tilting forward. When the ideal angel is reached, the pneumatic cylinders are activated, releasing energy from the tendon, and the kangaroo takes off. During the flight phase, the kangaroo pulls its legs forward to create torque at the its hip -- movement from the tail helps compensate, so the body stays mostly horizontal. When it lands, the tendon is tensioned again. This converts the kinetic energy of the previous jump into potential energy that’s stored. The company explains:
The landing phase is the critical process for recovering the energy and is responsible for the kangaroo's efficient jumping behaviour. During this phase the tail moves towards the ground and thus back to its starting position.
To keep going, the kangaroo applies the stored energy to the next jump. Here’s a video of the BionicKangaroo in action. Go roboroo, go!
Janet Fang has written for Nature, Discover and the Point Reyes Light. She is currently a lab technician at Lamont-Doherty Earth Observatory. She holds degrees from the University of California, Berkeley and Columbia University. She is based in New York.
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