One-legged hopping robots are nothing new. In most cases, they are tethered for energy and are not portable enough. Disney has unveiled a new approach for design and control of an untethered, energetically autonomous one-legged hopping robot. Called LEAP (linear elastic actuator in parallel), this mechanism consists of:
a voice coil actuator in parallel with two compression springs, which gives our robot passive compliance. An actuated gimbal hip joint is realized by two standard servomotors
The robot can maintain balance for up to 7 seconds or 19 continuous hops. More information is available here.