MIT's latest robot can do backflips, walk and trot on uneven ground. It’s rivaling Boston Dynamic’s bots. The mini cheetah can even be programmed to perform certain tasks when it dealt with unexpected force or kicked to the ground. Researchers say this is only a research project, so it's not likely to go on sale anytime soon or ever, if at all.
The cheetah bot can do backflips, trot on uneven terrain and even can be programmed to recover from shut down. (Image Credit: MIT)
The concept of backflipping robots isn't anything new. Boston Dynamics' robot, Atlas was able to do backflips in November 2017. The mini cheetah is the very first four-legged robot to accomplish this feat, and it's a smaller sized version than last year's cheetah 3. Cheetah 3 is a larger, heavier and formidable robot that needs to be supported with tethers to protect its parts. The mini cheetah can also move around like a crustacean due to its ability to imitate a crab by bending and swinging its legs wide enough to walk upside-down or right-side up. The robot is also springy and light on its feet, making it easy to move around and accelerate - trotting on uneven surfaces twice as fast as the average human's walking speed. Weighing at only 20 pounds, the robot can easily get back up on its feet by swinging its elbows around. What's more impressive is how it can do a 360-degree backflip and it's indestructible, allowing it to recover from minimal damage.
The robot is designed with modularity, so if one of the legs ever breaks off or the motor stops working, it would be fairly easy to replace. All the legs are powered by three identical, inexpensive electric motors made from off-the-shelf parts. The design of the electric motor was done by reconstructing the parts to smaller motors normally found in drones and remote-controlled airplanes. All twelve motors are the size of a jar lid. The stator, or set of coils that creates a rotating magnetic field, a small controller that guides how much current the stator should create. A rotor lined with magnets rotating with the stator's field, creating torque to allow the lift to ascend or rotate a leg, a gearbox that creates a 6.1 gear reduction, allowing the rotor to give six times the amount of torque it normally would create. It also has a position sensor that measures the angle and placement of the motor and limb.
Each robotic leg is powered by three motors, allowing it to have three degrees of movement and lots of motion. The lightweight structure of the mini cheetah allows it to move around on the ground quickly and precisely. It can also make contact on the ground without damaging the gearboxes or any of its legs. It can alter the way it moves on the ground by speeding up. While moving on the ground, its feet are only stable for 150 milliseconds at a time. A computer then tells it to apply more force on the foot, change to balance and then decreases the force to lift the foot up. This enables it to jump up in the air or run with two feet on the ground. It's not something most robots can do so they aren't as quick as the mini cheetah.
Testing took place through the hallways of MIT's Pappalardo Lab and on the uneven terrain at Killian Court, going through a number of maneuvers. The robot was able to run on the ground with complete success at five miles per hour. There is more potential with the robot and its speed - its joints are capable of spinning three times faster and twice the torque, resulting in the robot running twice as fast. To add more functionality, the team added more code to make it stretch and twist in many different yoga-like ways. This was used to show how the robot can move around effectively by rotating its limbs and joints while keeping control of its balance. The robot can also recover very easily from an unseen force. When it was kicked down to the ground, the robot shut itself down. After the robot starts itself back up again, it determines where it's standing then performs a command to put itself back up on its feet.
Researchers of MIT will be presenting the design of the mini cheetah at the International Conference on Robotics and Automation in May. They are also in the process of building additional robots, hoping to loan them to other labs. This will give other engineers and researchers an opportunity to test out the maneuverability and algorithms of a high-tech robot.
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