hopper
Image: Sandia National Laboratory

When Rush Robinett of Sandia National Laboratory's Intelligent Systems and Robotics Center (ISRC) went trout fishing a while back, he first needed to collect some grasshoppers as bait. And as he was chasing the jumping bugs, he had an idea. "I noticed they jump around in a random fashion, hit the ground in an arbitrary orientation, right themselves, and jump again. I said to myself, 'I can make a robot do that.'" Now, after years of work with several colleagues, he has. The scientists see applications for their hopping robots ranging from exploring other planets remotely and gathering wartime intelligence to assisting police during standoffs and surveillance operations.

In fact, Sandia has developed several automatons that go airborne. One resides within a grapefruit-size plastic shell, which lets it roll around to right itself after each jump. A pre-programmed microprocessor reads an internal compass and a gimbal mechanism then moves weights inside the machine appropriately. A combustion chamber fires a single piston that punches the ground, sending the hopper about three feet up and six feet forward per jump. A single tank of gas--about 20 grams of fuel--lasts through some 4,000 hops. Sandia developed another hopper for the Defense Advanced Research Projects Agency (DARPA) as an experimental mobile land-mine platform. This device shoots 10 to 20 feet into the air and can manage 100 hops on a tank of fuel (in photo).

We spent a long time getting here," says ISRC's Gary Fischer, who developed the unique internal-combustion engines needed to give the hoppers sufficient energy. "It wasn't easy," he adds. But now should come some fun. The team is fine-tuning the designs, creating versions that can be controlled by joysticks, as well as ones with shock-absorbing rubber shells that can bounce off concrete. "You'd like a robot that marines or SWAT teams could toss into a second-story window, then hop it around for a look inside," says senior scientist Barry Spletzer. "That could save lives. But where we want to go is Mars and the moon. With a hopper, you could go much farther from the lander. You could throw out a dozen of these to search in all directions."