Helping to advance biomimetic and tether-free robotics, the Massachusetts Institute of Technology (MIT) recently tested their latest running robot, the Cheetah, that ran, jumped, and walked without being tied to bulky cords and electronic wires.
Inspired by the fastest animal on the planet, MIT’s Cheetah reached a running speed of 10 mph across grassy terrain. Although not nearly as fast as a real life cheetah, which can reach speeds of 112 to 120 km
MIT developed a new algorithm that allows their Cheetah robot to move its legs in tandem much like real life cheetahs when running at top speed. The new algorithm also mimics another key feature demonstrated among the fastest animals, namely, the application of greater downward force when pushing off the ground. Doing this achieves longer strides, which in turn leads to faster running speeds.
Sangbae Kim, an associate professor of mechanical engineering at MIT, says, “Many sprinters, like Usain Bolt, don’t cycle their legs really fast. They actually increase their stride length by pushing downward harder and increasing their ground force, so they can fly more while keeping the same frequency.”
Other benefits to this force-based approach to robotics include increased stability when encountering obstacles. Instead of fitting delicate force sensors on the feet of their robot, MIT’s Cheetah uses high-torque-density electric motors that are controlled by amplifiers to achieve greater speeds without compromising stability. “Most robots are sluggish and heavy, and thus they cannot control force in high-speed situations,” says Kim. “That’s what makes the MIT cheetah so special: You can actually control the force profile for a very short period of time, followed by a hefty impact with the ground, which makes it more stable, agile, and dynamic.”
In time, these MIT researchers and engineers hope to bring the Cheetah’s running speed up to at least 30 mph.