A new robot called the X2-VelociRoACH is setting land-speed records for small, legged robots. The bot, which weighs in at 54 grams, can run up to 4.9 m/s with stride frequencies up to 45 Hz.
Built by researchers at UC Berkeley’s Biomimetic Millisystems Lab, the X2 features six speedy legs. But these legs don’t operate like the legs on a real roach or those of a fast moving animal, such as a cheetah.
Living things normally pick up speed either by increasing the length of their stride or the number of strides taken per unit of time. But the muscles and bones in living things tend to max out at a certain stride frequency which is why humans (and roaches) gain speed beyond that point by increasing the length of their stride. The X2, in contrast, moves super fast by increasing stride frequency, while maintaining the same stride length. Basically, the motors are made to spin very fast, though the length of each stride stays the same.
Several materials were tested for the legs and joints, but ultimately the researchers achieved the best performance with fiberglass legs and ripstop nylon joints.