Humanoid Robots
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NOW Then and HUMANOID ROBOTS by Tom Carroll n my many articles over the years, bipedal creature that to engineer the com- on after a dive. I’m not sure if it was any II’ve managed to mention just a few plex machinery required for the illusion. more comfortable than the ‘Maria’ suit tantalizing tidbits about the progress Gort from the classic 1951 sci-fi film worn by actress Brigitte Helm in the being made in humanoid robots, but The Day the Earth Stood Still (DVD avail- earlier classic movie Metropolis, filmed have just categorized that information able in Nuts & Volts webstore for $14.95; in 1927 (see Figure 2). Much later, Star within the context of the particular www.nutsvolts.com) was actually Lock Wars producer George Lucas used article that I was writing. In June ’06, I Martin, a very tall doorman recruited from diminutive actor, Kenny Baker crammed wrote about the development of Grauman’s Chinese Theater in Hollywood, inside the body of R2D2 in 1977 (and all walking robots in this column, however, CA (see Figure 1). The rubber ‘Gort suit’ later sequels) to give life to the ‘robot,’ humanoid form goes quite a bit beyond was so uncomfortable that Martin could as mechanisms of the day could not simple bipedal walking machines or only stand it for 30 minutes at a time and produce the rocking motion and give even the addition of a ‘head’ as the it was so restrictive to his movements that movement to all of its many functions. center of information-gathering sensors. he could not pick up the actors that he Actor Anthony Daniels was similarly The earliest robots were always was seen to ‘carry about.’ Wires and stuffed into a gold robot suit not too anthropomorphic or ‘man formed’ and moveable stands were used to support unlike the Maria costume of a half the plays and movies from the beginning the people out of sight of the camera. century earlier to give motion to C-3PO. of last century depicted them in this way. As an active scuba diver in the ‘60s In people’s minds decades ago, most Of course, a human was inside a robot and ‘70s, I can just imagine how robots had to look like bipedal suit so it was much easier to use an actor uncomfortable a rubber suit could be humanoids and the only way to animate to give movement to a human-sized after standing in the sun with a wet suit these robots was to place a human inside a robot suit. The cute little beeping, FIGURE 1. Gort the robot and FIGURE 2. Maria, the robot rolling trashcan-looking R2D2 was the Klaatu the alien. in Metropolis. exception to the humanoid appearance. Why Humanoids? What is the draw for experimenters to build a humanoid robot rather that a wheeled machine? They are more expensive to construct, especially if the designer uses a pair of legs for propulsion instead of wheels. They are more unstable and can be easily tipped over, either accidentally or on purpose. Reliability is another factor; one bad leg joint or actuator out of many and the robot is out of commission. I’ve followed a series of postings on the Seattle Robotics Society’s website (www.seattlerobotics.org) entitled “Legs not Wheels” for over a month. 78 SERVO 11.2007 There are strong feelings for both types Mellon University had developed some of robots and the reasoning is sound for amazing one-legged walkers, but the both camps. If you want to showcase very expensive Asimo gave the world’s your robotics talents, your biped robot experimenters the unofficial go- humanoid robot walking across a table ahead to develop their own creations. and taking a bow is certainly a great way Human-sized humanoid robots to add a feather to your hat. Coolness proved to be quite expensive to comes up strong as a reason for experi- develop due to the many DOF (degrees menters to want to build legged robots, of freedom) or axes of motion required especially bipedal robots. They just reek to approximate human leg, body, and of coolness. Plus, humanoids look like the arm motions, so small humanoid creatures we are most familiar with — us. walkers became very popular. Another strong point for humanoid Quadruped and hexapod robots had robots is the technical challenge been the ‘walker of choice’ for decades required to design and build a humanoid among robot experimenters. robot. A designer of humanoids just The availability of numerous types FIGURE 3. Honda’s Asimo. doesn’t make two legs cycle one in front of model aircraft servos as the drive of the other. He must take into consider- source for each axis of the legs became he worked with NASA, JPL Labs, and ation the center of gravity and balance, the final solution for the potential DARPA to develop energy efficient natural resonance of the mechanisms humanoid robot designer. These servos robots for space and other harsh involved, foot design, kinematics, were as cheap as $10-$15 per axis so environments. He formed his own com- synchronizing all of the joints and the transition to a bipedal humanoid pany to sell his very unique creatures actuators, hip and upper body position, from the small table-top wheeled robot and then joined with WowWee Toys to and a multitude of other factors. was a bit easier. sell his most noteworthy creation, the The builder must also take into Robosapiens and its offshoot creations. account just where the robot will be used Humanoid Robots Robosapiens make an ideal first — outside, indoors, on a table, in a robot for those interested in humanoid competition, or all of the above. Statically Become Available to designs. It comes ‘ready to roll’ right stable gaits have been the easiest for Experimenters out of the box and is priced as low as bipedal robot builders to achieve, though $100, with later improved models a few experimenters have built running It did not take long for the major under $200. The cost is low, not only robots. We must remember, however, walking robot kit manufacturers to because of the mass production in Asia that many large companies have investi- make the leap from hexapod or but the simplistic mechanical design gated walking robots as a natural way for quadruped robots to bipedal that makes use of just a few motors to a machine to traverse a specific area, and humanoids. Mark Tilden — long known perform many degrees of freedom have found out that legs are better for for his work with the Physics Division of motion to the arms and legs, much the certain tasks, while other applications the Los Alamos National Laboratory — same as the old Armatron robot arm. work better with wheels. General Electric the UK born, ex-Canadian resident is Tilden’s humanoid robot can walk built several large walking robots that best known for his tiny BEAM (Biology, at two different speeds, turn, dance, ended up with no application, yet Boston Electronics, Aesthetics, and Mechanics) and has two types of grippers (it Dynamics built the Big Dog robot that robots powered by the smallest solar reminds me of a robot lobster, in a just might make it onto the battlefield in cells and capable of interaction with the way). It also has various sound effects the near future. environment without even a simple (one is a caveman type of speech) microcontroller. Quite a few of us are and 67 pre-programmed functions. Humanoid Robots familiar with Isaac Asimov’s Three Laws Become a Reality of Robotics, but Tilden has come up FIGURE 4. V2 Robosapiens. with his own rules, uniquely suited to Despite all the movies and the many his early robot designs and their need to decades of wishing that true humanoids extract power from the environment: were among us, it wasn’t until Honda’s series of almost human-sized robots 1) A robot must protect its existence at leading up to Asimo that humanoids all costs. actually became a reality (see Figure 3). 2) A robot must obtain and maintain The company spent uncounted millions access to its own power source. of dollars (billions of Yen) in research 3) A robot must continually search for and development of this amazing robot. better power sources. Certainly university labs had toyed with the idea and Marc Raibert of Carnegie- Through his work at Los Alamos, SERVO 11.2007 79 Many Servos Required expensive Dynamixel RX-28 and RX-64 smart actuators, costing $200 and $285 for a Humanoid respectively, are significantly more sophis- As I mentioned earlier, the advent of ticated in their onboard intelligence and the inexpensive yet unique model torque. For the serious humanoid airplane servo made complex humanoid designer, they are worth the money construction possible for the robot and are available at CrustCrawler (www. experimenter. Most fully articulated crustcrawler.com) and other SERVO humanoids require 16 to 20 or more advertisers. Humanoids can be expensive servos to approximate many of the and complex to construct; it really human joint actions, both with the legs depends on your design and budget limits. and the arms. Even at $15 per servo, this amounts to $240-$300 just for the ser- Humanoid Kits vos. Add a microcontroller, power pack, basic sensors (visual, communications, Many experimenters opt to start accelerometers, etc.), and the many from scratch, but many types of kits complex structural members and you can are available. The Hitec ROBONOVA-I FIGURE 5. The RS Media robot begin to see why many kits top $1,000.