U.S. olympian Mike Powell made history in 1991 at the summer games in Los Angeles when he leaped over 29-feet in the long jump. Already towering at 6 feet 2 inches, Powell’s jump was equivalent to 4.7 times his own height and is still undefeated — at least, by human beings.
In a new paper published Tuesday in the journal Nature Communications, a team of roboticists has designed a teeny-tiny robot — only 2.5 inches long and 1.1 grams — that has achieved a long jump equal to six times its body length.
Even more, the robot achieves this Olympic world record-breaking jump without any legs. Luckily for Powell, this robot isn’t training for the Olympics. Instead, the researchers write that it could be the future of deadly pollutant detection in our cities.
What’s new — Rui Chen is an associate professor of mechanical engineering at Chongqing University and the first author of this new paper. He tells Inverse that the inspiration to design a legless robot came from studying how nature solves this problem.
“Most creatures need feet to jump, but some creatures — such as gall midge larvae — can leap by bending of their bodies, which gave us the inspiration to develop a jumping robot without legs,” Chen says.
Using electric stimulation, the robot can jump continuously without delay to reset.
Giving your jumping robot legs can mean considering more joints and mass when designing the jumping mechanism. In a word, it can be a less streamlined design. Legless robots, on the other hand, can avoid some of these complications. And while Chen and colleagues aren’t the first to develop this kind of robot, they write in their paper that this new design is an improvement on existing legless robots.
As they write, these robots typically have two problems:
- They can have a large jumping height and sacrifice time for resetting and storing energy
- They can reset and store energy quickly but sacrifice jumping height
Taking elements from several different designs, Chen and colleagues designed an electro-hydrostatically driven robot that can do both.
Why it matters — This frisbee-shaped robot is still in its infancy, but Chen and colleagues say that in the future, it could be used to trek across dynamic terrains, like mounds of gravel, or patrol office buildings sniffing out pollutants.
Using air, oil, and electricity the robot is able to hop across a lab without any legs.
How they did it — Similar to the larvae Chen was inspired by, which move by contracting and releasing muscles, this robot jumps along via the redistribution of fluid in its “abdomen.” In place of muscles, the team equipped the robot with:
- A semi-circular baggy of air
- A semi-circular baggy of dielectric liquid (e.g., an oil)
These internal components are then all held together within a plastic ring frame. When the robot receives an electric jolt, the flow of the dielectric liquid changes and redistributes forward. In turn, the rest of the robot body leaps upwards to follow it with the air bubble acting similarly to a tail, the authors write. The system then returns to its original state after landing — ready to jump again within a matter of seconds.
The robot was able to scale a number of dynamic environments, including loose gravel.
In several trials performed in their lab, the team found that this robot can climb over many obstacles, including mounds of gravel, cables, and stacked blocks. However, the robot hit a snag when attempting to perform these moves on different textured surfaces, particularly on a smooth glass surface. In the future, the team writes that electro-adhesion could be used to solve this problem.
What’s next — In addition to the glass problem, Chen says that the team plans to optimize several other aspects of their robot in the coming years, including its scale and releasing the robot from its tether for more open exploration of environments.
They may even teach the robot some new tricks in the process, Chen says, including “other soft robotics applications such as wall climbing robots, swimming robots, and flapping-wing robots.”
Abstract: Jumping is an important locomotion function to extend navigation range, overcome obstacles, and adapt to unstructured environments. In that sense, continuous jumping and direction adjustability can be essential properties for terrestrial robots with multimodal locomotion. However, only few soft jumping robots can achieve rapid continuous jumping and controlled turning locomotion for obstacle crossing. Here, we present an electrohydrostatically driven tethered legless soft jumping robot capable of rapid, continuous, and steered jumping based on a soft electrohydrostatic bending actuator. This 1.1 g and 6.5 cm tethered soft jumping robot is able to achieve a jumping height of 7.68 body heights and a continuous forward jumping speed of 6.01 body lengths per second. Combining two actuator units, it can achieve rapid turning with a speed of 138.4° per second. The robots are also demonstrated to be capable of skipping across a multitude of obstacles. This work provides a foundation for the application of electrohydrostatic actuation in soft robots for agile and fast multimodal locomotion.