9 January 2014
You’re a defense contractor working for DARPA. Instead of being asked to develop a flying robotic drone, you are contracted to design and build a robot that runs fast and can walk through rough terrain.
So, you design your robot to imitate . . . a bird? Yes, a bird. The world’s fastest running animal is a bird. A flightless bird. The ostrich. In fact, the ostrich can run so fast, it’s probably never felt the need to fly.
DARPA has funded the joint effort of MIT and the Florida Institute of Human and Machine Cognition (IHMC) in a project to develop a robot that walks and runs. Past DARPA-funded projects have resulted in the quadrupedal robots, BigDog, Robo-Cheetah and the Wildcat. But the end result of this latest effort will be the first robotic biped in the DARPA arsenal.
Robo-Ostrich is designed not just to walk, but to run and run fast. Although the first full prototype has yet to be designed, the working computer simulation has legs and is hitting speeds of 27 mph. Impressive considering this is about the speed of the fastest human runner – in a hundred yard dash. But this robot could sustain that speed indefinitely.
The designers, however, aren’t satisfied with a mere 27 mph and are hoping to, eventually, develop a ‘bot that will reach a speed of 50 mph. And the 50 mph mark would be another milestone on two counts. First, real ostriches clock no higher than about 43 mph. And, second, real ostriches are the fastest land animals on earth. So, the 50 mph Robo-Ostrich would not only beat the real bird, but would also beat every other land-based animal on the planet.
Although this ‘bot is formally named “FastRunner,” it has come to be known, informally, as Robo-Ostrich. Why? Because the only way to develop a robot that could run as fast as an ostrich was to build its legs to as closely imitate the legs of a real ostrich as possible. By the way, this is called biomimicry – designing a technology to imitate nature in order to solve a complex human problem.
Indeed, everyone is so excited about the Robo-Ostrich’s performance that it’s easy to forget that this robot doesn’t really exist. Right now, the ‘bot is a computer simulation, which is only about 40% complete.
However, this isn’t the “damper” it once was because modern computer simulations are remarkably good. In fact, modern computer simulations are so good that they quite precisely predict the performance of the real things they simulate. So, if you can “get it right” on the computer, you can break out your hammer and wrench (figuratively speaking) and start building. But the building phase for Robo-Ostrich is still “a ways off.”
The development of Robo-Ostrich is particularly significant because this robot’s working legs will incorporate advanced technologies to maintain the robot’s balance. In the past, designers attempted to build complex systems into robotic legs that would monitor and respond to every variation in movement on every type of terrain. This required large, on-board computers, complex programs, and equally complex mechanics to control every aspect of simulated walking and running.
However, a new non-linear approach is being used in the development of Robo-Ostrich. Although complicated to develop, the new system will be of a much simpler design.
To oversimplify, imagine your automobile with computers in each wheel monitoring every bump and, then, commanding the suspension system to precisely respond in order to compensate for each disruption. Readers familiar with automotive suspension will furrow their brow and ask, “Why?” For almost a century, automobiles have used a spring that flexes when the tire rolls over that speed bump (for example) and, then, returns the chassis to its original position – no computers required.
Very, very roughly, a similar set of principles are being used to develop the mechanics of Robo-Ostrich’s legs. Though much more complex than an automobile suspension system, the goal is a relatively simple, self regulating balance mechanism that allows the ‘bot to maintain its balance as it walks over uneven surfaces.
The real ostrich can grow to a height in excess of 9 feet with a weight as high as 250 pounds. In other words, you wouldn’t want to meet the real bird – in a bad mood — in an ally — at night.
Robo-Ostrich, however, will only measure about half the height and weight of the real bird. This relatively “petite” size and weight produce an intended advantage. The lighter weight makes the robot faster and lowers its power requirements extending its range.
The two legged design has distinct advantages over the past quadrupedal models. Not only is a two-legged robot lighter, but its movements are more flexible allowing it to, among other things, “get through narrower spaces” and maneuver more easily around obstacles. With such a flexible build, this robot, like other “be-footed” robots, is designed to negotiate rough terrain that would defy a wheeled-vehicle like a jeep. Even on irregular surfaces, the finished ‘bot is expected to run (or walk) at a speed of 10 mph.