Starting as far back as the 1970s, robots invaded the factory floor in huge numbers, transforming the manufacturing environment. On the contrary, service robots in hospitals, nursing homes, stores, and private residences have yet to make even a marginal impact.
Originally, it was expected that the greatest challenge in creating a world in which robots smoothly interacted with humans would be to create a machine that could think intuitively as we do. As it turns out, great strides in processing power as well as breakthroughs in neural networks, which mimic the neuron structure and operation of the human brain, have enabled the "thinking" component of robots to progress quickly. As IBMs Watson machine demonstrates, weve actually made big strides in getting computers to give the appearance of human-like cognition.
However, getting machines to move and manipulate objects as effortlessly as humans do has proven more daunting. Simply the fact that we still label public speakers who gesture stiffly as "robotic" tells us that robots have a ways to go before they master "natural movement." In fact, one of the key identifying characteristics of robots has been the precise, mechanical, and even somewhat abrupt way in which they move.
This is largely due to the hydraulics and gears that are used to perform the functions of muscles in robots. The resulting jerky movement can be thought of as "digital," whereas the smooth movements of humans are "analog." Its the difference between the way a digital clock moves from one second to the next in distinct jumps, as compared to the smooth, sweeping second hand of an analog clock.
But now, thanks to new breakthroughs in computing and materials science, robotic movement may soon be improving. Several new approaches to artificial muscles for robots are offering the prospect of smoother, more human-like movement.1
One method is being developed in the Auckland Bioengineering Institutes Biomimetics Lab in New Zealand. These new robotic muscles wobble like jelly and are composed of electroactive polymers. They are made up of two layers of conducting carbon grease separated by a flexible insulating polymer film that can be stretched by more than 300 percent. They would make robots feel soft and fleshy, but more significantly, they have the potential to make robots move with the dexterity of humans, without the typical rigid mechanical robotic components.
A company called Artificial Muscle in Sunnyvale, California is developing another application for this type of electroactive polymer-based motor. It is designing touchscreen displays which respond when they are touched, providing tactile feedback. In the not-too-distant future, we will get the sensation of clicking on a real button when tapping on a cell phone touchscreen. Applied to robots, this tactile feedback technology will allow them to become even closer to being human-like.
Scientists at the University of Texas at Dallas are also developing robotic muscles that provide smoother movement.2 Their approach is to use an elastic metal called "shape memory wire." In a departure from most robotic muscles that are powered by an electrical current, these muscles are powered by chemical energy, which, interestingly, mimics human muscles.
Much of the research behind creating life-like prostheses to aid the handicapped overlaps with what’s needed for anthropomimetic robots. As artificial muscles and other technologies come closer to mimicking human movement, they will benefit from a new wellfunded market for devices that give humans natural movement with enhanced capabilities.
Shape memory wire exhibits an unusual characteristic that enables it to act as a muscle. When heated, it contracts, rather than expands. To capitalize on this behavior, researchers have coated the material with a catalyst that causes alcohol to burn. When alcohol is added, this burning creates heat, which contracts the material, much as our muscles contract to produce their force.
When the flow of alcohol is turned off, the muscle expands. The expansion and contraction of this shape memory wire is fully based on temperature.
According to head researcher Ray Baughman, "These artificial muscles are able to do over a hundred times more work per cycle than a natural muscle. Theyre a hundred times stronger than an actual muscle."
Another leap forward toward a more human-like robot is a creation named Ecci. Ecci was developed by a team of scientists at the University of Zurich. Its arguably the most advanced robot ever created, with tendons, muscles, bones, a brain, and the visual capability of a human.
The team had three goals in mind in creating the robot:
1. To build the first truly anthropomimetic robot, defined as "one which imitates not just the human form, but also the biological structures and functions that enable and constrain perception and action"
2. To find out how to control it
3. To investigate its human-like cognitive features
The team has succeeded in building a robot that features a skeleton that very closely replicates that of the human body. It is made of bones and joints formed out of thermoplastic polymorph, a specially developed plastic.
Its the way it copies the inner structures and mechanisms of the human body that provides the possibility for it to produce human-like action and interaction. This human-like action offers an enhanced ability to gain knowledge of the surrounding environment, which in turn improves its cognitive engagement with the environment.
The developers point to the robots ability to correct its mistakes, a decidedly human trait, as its most advanced capability. For example, Ecci can analyze a movement that caused it to stumble and learn how to avoid that same mistake in the future.
Its movements are made by individual actuators for its 80 muscles, and it employs proprioception, which is the ability to sense the relative position of neighboring parts of the body, to refine its movements and interaction with its environment. This feature helps modulate the muscle length and muscle force needed for any action or movement.
For proper grasping ability, tactile sensors in the fingertips and palms of the robots hand provide indispensable feedback.
Ecci features both voluntary movement control as well as involuntary movement control, which is similar to human reflexes. This gives it the ability to quickly react in the case of accidental touch.
Finally, Ecci has a brain that provides cognitive functions and determines the behavior of the robot. This control center includes a perception unit, a planning unit, and a decision-making unit.
Based on this trend, consider the following three forecasts:
First, humanoid robots will ultimately assume responsibility for many daily chores.
Weve already seen a line of housecleaning robots from iRobot, such as the vacuuming Roomba, the floor-washing Scooba, and the pool-cleaning Verro, as well as lawn-mowing robots such as the LawnBott from Kyodo America Home Robotics. But those robots look more like autonomous power tools than the humanoid robots that will take over such tasks as dusting, sweeping, grocery shopping, and elderly care. With smooth, natural movements, speech recognition, and sophisticated artificial intelligence, theyll be capable of carrying out commands, holding conversations, and helping their owners who need assistance getting out of bed or walking across the room.
Second, human-like robotic hands will automate intricate manufacturing tasks.
Initially, robots have taken over repetitive, simple tasks, such as welding a particular part on an assembly line. This is relatively easy, since it only requires holding a welder and touching it to a precise point. With more sophisticated robotic hands that display human-like dexterity will come an increased capacity to perform complex - but repetitive - assembly tasks. In time, advanced muscles will be developed into super-muscles for use by workers or even soldiers.
Third, the biggest leaps well see in human-like robotics over the next 15 years will be by-products of medical applications for bionic prostheses.
Service robotics will remain a relatively small industry compared to health care, where a great deal of effort is being devoted to research into man-machine interfaces to aid the handicapped. Much of the fundamental research needed to make this happen overlaps with whats needed for a truly anthropomimetic robot with hands, arms, legs, and feet that move naturally. Similarly, as artificial muscles come closer to mimicking human movement, they will benefit from the larger-scale demand for creating prosthetics that give people not only more natural movement, but enhanced capabilities. Artificial hearts will also benefit from the new types of artificial muscle. Therefore, anthropomimetic robots and medical protheses will develop in parallel to their mutual benefit, sharing research and other resources.
References 1. New Scientist, March 17, 2011, “Rubbery Muscle Motors to Make Robots More Lifelike,” by Duncan Graham-Rowe. ⓒ Copyright 2011 by Reed Business Information Ltd. All rights reserved. http://www.newscientist.com 2. Discover Magazine, May 4, 2006, “High Powered Prosthetics,” by Victor Limjoco and Eva Gladek. ⓒ Copyright 2006 by Klambach Publishing Co. All rights reserved. http://discovermagazine.com
