Insects have the solution to a very serious limitation of small robots. When a small robot has to navigate difficult terrain such as a rock-strewn surface of another planet, it faces a problem. This difficulty is that to a small robot even a small pebble is a giant boulder.
Researchers have described the problem in the following way:
"Small robots have big problems when it comes to efficient locomotion in natural and rough terrains. This effect is usually referred to as the 'Size Grain Hypothesis' , which is described as an 'increase in environmental rugosity with decreasing body size'. That is the smaller the robot, the bigger the obstacles. To circumvent the inefficiencies of crawling, walking, or running for miniature robots, researchers at EPFL are exploring jumping as a more efficient approach (others have also developed jumping robots.)"
Some insects have utilized this mode of transportation for a long time. Certainly, this is a very efficient way for insects to get over blockages in their path. Jumping allows a more direct line of travel in most cases. Small robots can utilize this same way of getting around in a rough terrain. In this paper researchers present their research on an original 5cm, 7g jumping robot. It can leap over obstacles "more than 27 times its own size and outperforms existing jumping robots by one order of magnitude with respect to jump height per weight and jump height per size."
The big question is--how does this little bot work? The short description as given by the researchers in the recently published paper is the following.
"It employs elastic elements in a four bar linkage leg system to allow for very powerful jumps and adjustment of the jumping force, take-off angle and force profile during the acceleration phase."
Miniature jumping robot
Wed, 22 Oct 2008 07:27:00 GMT
M. Kaspari and M. D. Weiser, “The size-grain hypothesis and interspecific
scaling in ants,” Functional Ecology, vol. 13, no. 4, pp. 530–538,
Kovac, M. , Fuchs, M. , Guignard, A. , Zufferey, J.-C. and Floreano, D. (2008) A miniature 7g jumping robot . Proceedings of the IEEE International Conference on Robotics and Automation (ICRA'2008), pp. 373 - 378.