Most people shudder at the sight of a cockroach. Scientists, on the other hand, are fascinated. Cockroaches, as it turns out, are a biomechanical wonder that may help researchers design the world’s first legged robots that can run easily over the roughest surfaces.
Cockroaches are capable of instinctive muscle action that doesn’t require reflex control. For the most part, they don’t have to think about running--they just do it. Researchers at Oregon State University are trying to apply what they are learning from the bodies of these tiny insects to create running robots that can effortlessly cover rough ground.
“Cockroaches have sprawled postures. Their legs are splayed out to the side, and not underneath them,” said John Schmitt, an assistant professor in OSU’s school of mechanical, industrial and manufacturing engineering. “Their legs are pretty far from their center of mass. Evidently that makes them a lot more maneuverable; they can literally turn on a dime. They can react to disturbances [in motion] faster than a nerve impulse can travel.”
Ultimately, the information researchers hope to gain from studying this ability in cockroaches--as well as in guinea hens, which are also under examination--could result in creating robots that could run over rough terrain in dangerous situations, such as in the military, law enforcement or in space exploration. In humans, the knowledge might help produce better prosthetic devices.
For example, some day a military robot, rather than a human, could quickly run into a potentially perilous area, perform an assigned task, and return safely. In space, “you could have rovers with legs, instead of wheels,” Schmitt said.
Currently, some robots can walk, but none runs as effectively as its animal counterparts, according to the researchers. Even robots that walk use far too much energy and computing power to be very useful, they said. “What we hope to do in robotics is directly embed the simplified locomotion model of the cockroach into the robots,” Schmitt said.
A cockroach only slows down 20 percent when going over blocks that are as much as three times higher than their hips, an ability that is “just remarkable, and an indication that their stability has to do with how they are built, rather than how they react,” Schmitt said.
The OSU researchers are trying to identify the basic biological and mechanical characteristics that enable certain creatures to run with such little effort. The guinea hen, for example, can change the length and angle of its spring-like legs to almost automatically adjust to an unexpected change in ground surface as much as 40 percent of its hip height, they said. In human terms, that’s like someone running at full speed, stepping into a 16-inch hole--and never missing a beat.
“Humans can run, but, frankly, our capabilities are nothing compare to what these insects and some other animals can do,” Schmitt said. “Cockroaches are incredible.”
Researchers have made a computer model that allows a running robot to recover from a change in ground surface almost as well as a guinea hen. They are studying the interaction of energy storage and expenditure, sensor and feedback requirements and leg angles to learn about recovery from perturbations--those events or obstacles that disturb motion, such as pot holes--so they can apply them to future robot design. “Within 10 years we should see better robots than we have now,” Schmitt said.
The researchers’ findings explaining how animals use their legs to manage energy storage and expenditure were published recently in the professional journal Bioinspiration and Biomimetics. The work is funded by the National Science Foundation.
—Marlene Cimons, NSF.