Robotic hands have a hold on our imagination because they give us a tantalizing look at a fully automated future. At the same time, they're already helping us out with useful and difficult tasks, like making less invasive incisions during surgeries.
The 1980s USC Belgrade hand could not cut a person, but it was instrumental in the history of the development of robot hands. Known for its true anthropomorphic (human-like) design, it had four fingers and an opposable thumb with 5 degrees of freedom and was the first to be able to give a true handshake.
Capable of holding up to 5 lbs., the hand had four motors and 14 force sensors that provided the logarithm of where each finger was located. This was a key development for all robot hands. Later on, researchers added 'slippage feedback' that forced all fingers to adjust to unstable objects for a better grip.
Last weekend, we published a gallery of some of the best robotic hands of the past and present, and many readers requested a more in-depth look at those we didn't cover. So we got in touch with robotics pioneer George Bekey, the creator of the USC/Belgrade hand (and USC's current Professor Emeritus of Computer Science) to ask him about the beginning of the robot hand movement and where they'll go from here (they're going to classrooms!).
Here's our interview:
Wired.com: Y____ou've previously mentioned that the USC/Belgrade hand didn't receive the notoriety it deserved at the time. Why did that happen and what made it stand out in your mind?
Prof. George Bekey: The two leading hands at the time were the Salisbury 3-fingered hand, which came from Ken Salisbury's lab at MIT, and the 5-fingered Utah-MIT hand. [The former] became a successful commercial product, [and the latter] was the most sophisticated hand developed, also mostly at MIT by John Hollerbach. The National Science Foundation awarded 10 grants of $100,000 to universities for the purchase of this hand.
I was a beginner in robotics when Tomovic and I brought the hand to USC and added sensing and control. [But] I was not able to raise the funds to design and build a more sophisticated and reliable hand.
I did some funding for experiments using the hand as a prosthetic device, but the problems [with our hand] were related to the difficulty of controlling it from the stump of an amputee and the general lack of reliability of the hand itself. I believe that our control philosophy for using this robotic hand, as a prosthetic device, was excellent.
W: Let's go to the beginning. What got you into the robotics field when you were younger?
GB: I wanted to be an engineering professor from my early years as an undergraduate at UCLA. My early work was in human-machine systems, system modeling and identification, control and signal processing. [But] I did not discover robotics until about 1980 when I received an NSF grant to purchase a PUMA robot manipulator.
[But] by the mid 1980s I was hooked.
W: When did the development of the hand begin?
GB: The hand was a joint project between Prof. Rajko Tomovic of the University of Belgrade in the former Yugoslavia and myself. Tomovic developed the original at the end of WWII as a prosthetic device for veterans who had lost their hands in the war. He succeeded in getting funding from the US NIH for the project, but the hand was not successful. It was too complicated, not reliable enough, etc. But the principle of building a hand that could adapt automatically to the shape of an object to be grasped was valid.
W: What were the main challenges that you and your department faced when developing the hand back then? Both technically and within the University structure?
GB:__ __[After Tomovic’s early development] USC got involved and Tomovic and his colleagues had developed a Model 2 hand. [Our contribution] added sensors, motors and computer control. One of our major challenges was that the mechanical structure made in Yugoslavia was not good enough: It did not have tight tolerances and was not reliable enough. Also, I was not able to get funding to build a better one. A small company in Downey, CA built and sold two or three of the hands and we lost a lot of money in the process.
W: Prehension was seen as a key development for the USC/Belgrade Hand. What made it so special?
GB:__ __Other hands at the same time, like the Utah-MIT hand, required a very complex computer control system since each joint of each finger had to be individually controlled. In our hand, a contact between any finger surface and an object initiated a grasping motion that continued until the pressure on all the fingers was approximately equal. Thus, the hand was able to adapt to arbitrary shapes without any external control. This was the key development.
W: For years, robot hand development has swayed between a focus on muscular parts and skeletal structures. Where is the focus today? It seems like the question of stability has been minimized (due to stronger materials), but is that right? How will the hands become more precise, faster?
GB:__ I think the issue in multi-fingered hands is [still]
control, particularly if the hands are anthropomorphic and there is an attempt to imitate human control. Stability and control are interrelated. Some of the most intriguing hands I know [with innovations in these areas] are the NASA/Robonaut hand, the Shadow hand, and Dean Kamen's hand.__
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W: Are true anthropomorphic, 5-digit human-like designs the best way to build a robotic hand or are we limiting ourselves by focusing on our own body? Are more digits the answer? And are there physical materials that will improve the hands dramatically?
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GB:__ __I believe that 5-finger hands are particularly important for prosthetic applications, but not for robots. Most robot grasping can be done with 3 finger hands, or with special purpose grippers designed for grasping particular objects. I did a study once on the advantages of using 5-fingered hands for industrial assembly tasks and came to the conclusion that they created more problems than advantages, due to increased complexity.
[As for the materials], I expect that more fiber composites will be used.
Note: The Korea Advanced Institute of Science and Technology have recently created robot 'sandwich' wrists and hands using these types of fibers, which increase durability and tolerance.
W: The original tech of the hand has been surpassed now, but could the tech used back then be used in any type of application today, to take into account the high costs you've mentioned?
GB: There was a Model 3 hand with 6 motors: one for each digit and two for the thumb to rotate it into opposition with any of the other fingers. [Today], it may be worth pursuing as a low-cost prosthetic hand.
We have many mobile robots in university and industrial labs that would benefit from having one or two arms and hands, but cost is prohibitive. An arm-hand system has many degrees of freedom and is difficult to control; it must be reliable.
W: Finally, how do you think we can get kids interested in robotics so they can contribute to the field down the road?
GB: I frequently talk to middle school kids about robots. These talks include demos, and, whenever possible, I provide kits from which the children can build simple machines that move and avoid obstacles.
I think the key to get kids interested is not lectures, but experiences. For the past five years I have been an advisor to a high school robotics club that competes in the FIRST robotics competition.
I have seen kids who were potential dropouts change completely, decide that math is valuable, and make a commitment to go to college so they can work on robots when they graduate.
I believe we need to [place] kids with robots in the classroom, get practicing roboticists to visit classrooms. Robots are wonderful motivators.
All we need is budgets for the materials, and the commitment from organizations that will help to recruit people to help. I believe that the IEEE Robotics and Automation Society, or the ASME will be glad to help with finding volunteers to meet with classes to demonstrate robots. Jose, I certainly agree that this should be a national priority, and that robotics can be used to inspire large numbers of children to move into STEM careers.
Certainly, our country desperately needs to inspire a new generation of scientists and engineers and I believe that robotics can provide a powerful stimulus.
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