US researchers have adapted leg spines to provide insect like mobility to robots.
Researchers at the University of California, Berkeley, and Pennsylvania University, US, added steel spines, modelled on those on the spider's leg to a six-legged robot called the RHex. They also modified the legs to mimic the pattern of leg movement in cockroach and spiders when crossing over an obstacle.
The team found that the adapted robot could easily cross a wire mesh that previously blocked its path, akin to an insect or a spider that traverses across gap-ridden surfaces or the leaves of a bush.
For their study, the researchers used a high-speed video camera to observe funnel weaver spiders (Hololena adnexa) and cockroaches in slow-motion as they ran across both solid surfaces and a wire mesh with 90 percent less surface area.
The video showed the spider at 1/25 of its normal speed and a cockroach shown at 1/50 of its normal speed running over the mesh.
Researchers found that the spider was only 22 percent slower when running across the mesh, compared to the solid surface.
The team studied the slow-motion footage to work out how the creature knew where to put its feet.
They found that the physical design of the insects' and arachnids' legs made it easier for them to negotiate such terrain with relative ease.
"We saw that the animals distribute contact with the ground along the leg to avoid falling. It's a kind of mechanical feedback. If the foot of a leg misses the ground another part of the leg usually catches to help support the creatures," New Scientist quoted Bob Full from UC Berkeley as saying.
"The spider, which places its legs down vertically, does it using specialised spines. They support the body when pushing down, but can fold back when the leg is pulled upwards. When the spines were trimmed from one side of a spider's legs it was 25 percent slower at climbing over the mesh.
“Cockroaches do not use spines, but kept their legs horizontal to grip the mesh with parts other than just its tarsus, or feet,” he said.
The team now believes that the design will be useful for rescue robots that need to cover difficult terrain.