Fastest animals
The fastest land animal is the cheetah, which has a recorded speed of . The peregrine falcon is the fastest bird and the fastest member of the animal kingdom with a diving speed of . The fastest animal in the sea is the black marlin, which has a recorded speed of .
MABEL (robot)
MABEL (robot) is a robot engineered in 2009 by researchers at the University of Michigan, which is well known for being the world's fastest bipedal (two-legged) robot with knees. MABEL is able to reach speeds of up to 3.6 m/s (6.8 mph). The name MABEL is an acronym for Michigan Anthropomorphic Biped With Electronic Legs. The creators include J.W. Grizzle, Jonathan Hurst, Hae-Won Park, Koushil Sreenath, and Alireza Ramezani. MABEL weighs 143 pounds (65 kilograms) with most of its weight being in the top torso area. The legs contain large springs and are jointed to form knees. The robot is attached to a safety boom for lateral stability.
In order to make MABEL functional for extended periods of time, the researchers focused on ways to optimize powertrain efficiency. Unlike the RABBIT, MABEL was designed to have all four motors in the midsection instead of the legs. This makes the legs lighter and more agile. Secondly, most of MABEL’s power is stored in large springs that act to reduce shock and store energy. MABEL uses a differential so that the spring can be grounded by the torso of the robot instead of directly connected in series with a motor. This allows the compression in the springs to better apply force that pushes up the center of mass. Another innovative aspect of the springs is that they are referred to as “unilateral” because they don’t extend past the rest length, causing undirected force.