Springing through the Australian outback the kangaroo is a model of efficiency.
Thanks to its unique method of travel, this marsupial is capable of moving quickly for incredible lengths of time without using large amounts of energy. Every time a kangaroo’s feet hit the ground, the Achilles tendon in its hind legs stretches to store energy, and it uses that power for the next jump. You can think of it working in a similar way to a spring in a pogo stick.
Now the kangaroo’s graceful movements have been recreated by a development team from Festo’s Bionic Learning Network, a German-based supplier of automation technology.
The BionicKangaroo stands just slightly over three feet and weighs 15 pounds. The robot can hop a distance of about two and a half feet and can jump over a foot high. Through a combination of pneumatic and electric drive technology, it is able to recover, store, and retrieve energy to use on its next bounce, just like the animal it’s modeled after.
To achieve this, an elastic band made of rubber is fastened to the back of the robot’s foot, parallel to a pneumatic cylinder on the knee joint. This band serves the same function as the Achilles tendon in a real kangaroo, cushioning the hop while simultaneously absorbing kinetic energy and releasing it for the next jump.
“Most interestingly, we combine electrical and pneumatic drives,” explains Annette Ostertag of Festo’s technology division of the corporate communication team. “The electrical drives are necessary for precise movements while the pneumatic actuators are necessary for the dynamic jumping behavior.”
When the robot is ready to make a leap, pressurized gas makes the elastic tendon tense up, and motors near the hip of the roo kick in, making the biomimetic animal lean forward. When it reaches a certain angle, energy is released and allows the robot to hop.
Integrated controls, condition monitoring, and real-time diagnostics allows the robot to have stability while jumping and landing. If for any reason the angle of the jump is off, the system can monitor itself, consider the variables that could cause a shaky take-off or touch down, and use a set of algorithms to make sure it does not crash. When it’s not busy hopping about, the BionicKangaroo rests on its small front arms for stability.
For power, the BionicKangaroo relies on two sources: A small compressor that provides high pressure air for the pneumatic muscles that power the jumping, and lightweight batteries that energizes the entire robot.
Probably the most fascinating aspect of this whole project is how the engineers decided to control this tiny robo-marsupial. Instead of using something like an RC remote, the BionicKangaroo is directed through gesture controls.
A human wearing a Myo armband from Thalmic Labs can interact with the robot without having to touch any inputs. The band’s Microsoft-Kinect-like technology is Bluetooth-enabled and has a range of 54 feet.
“We decided to use gesture control as a possibility of man-machine-interaction, a field that is very interesting for us,” explains Ostertag. “We are constantly researching in the field of handling and control of automation technologies, and gesture control could be one possibility in the future.”
Showcasing the power of biomimetics
Consumers excited by the prospect of owning their own robo-kangaroo may be disappointed to hear that they won’t be in stores anytime soon. Festo doesn’t intend its creation for everyday individuals to play with. Instead, this project is a tool in showing the power of biomimetics—a field of science that uses natural-world designs to create things to benefit humans—and inspire would-be engineers.
In practical terms, Festo believes that the robot’s unique movements, based on the principal of “recovering, storing, and releasing energy based on a natural model” to facilitate movement, could be an intelligent way of recovering energy in industrial automation and might be applied to the automated tools it makes for factory assembly lines.
“Together, the electrical and pneumatic drive technology leads to a highly dynamic system which is still very energy-efficient,” says Ostertag. “All of these learnings will find their way into the products of the future.”
The BionicKangaroo isn’t the first bionic robot that the Festo team has created. In fact, the company has made a name for itself with its various “biomimetic” robot designs that take their operational characteristics from animals. The Bionic Learning network has created everything from bionic jellyfish to an incredibly realistic robotic seagull, applying principles from nature to inspire new technical applications and industrial practices.
Photo courtesy of Festo