ARS: First, we would like to thank you for giving us this interview and the time you spent to answer our questions. Can you please briefly describe your scientific career and how did you become connected with robotic?
Bar-Cohen: Let me started with few words of background about my career and the philosophy that guides me. In the early part of my career I specialized in ultrasonic nondestructive evaluation (NDE) but later I broadened my activity to electroactive actuators and mechanisms and then to robotics and biomimetics. I attribute my ability to do so many things in so many disciplines to my imagination, creativity and hard work; but above all it comes from effective collaboration with top experts worldwide. My idea of cooperative research with interdisciplinary experts was biologically-inspired from the world of ants who collectively are capable of performing impressive tasks that are far beyond what they are expected to be able to do as individuals.
In 1967, I started my academic education majoring in Physics at the Hebrew University, Jerusalem, Israel. Just about the time when I was ready to apply to graduate school, the university started offering M.Sc. degrees in applied science. I found this program highly attractive since I had more interest in the practical aspects of science and I chose to focus on Materials Science. This two-year program included a summer internship at the industry and I selected the topic of NDE at the Israel Aircraft Industry (IAI). My work in NDE required a lot of self-learning and it allowed me to deal with multidisciplinary challenges related to aerospace. Since I chose for my thesis the subject of NDE of bonding where I dealt with an important issue for IAI, by the end of that summer of 1971 I was hired as a consultant to work on the thesis on-site. As soon as I graduated in 1972, I was hired by IAI as a full time employee and established the in-house R&D program. It is interesting to note that I was the first student to graduate the School of Applied Science at the Hebrew University.
After two years at IAI, I felt the need to enhance my background so I started studying towards PhD. This has been a highly demanding period in my life since I worked at full time level on both the PhD thesis and as an IAI employee and at that time I had already 2-year old twins whose raising I wanted very much to enjoy. The subject of my PhD thesis was ultrasonic imaging and I developed a device that projects an ultrasonic image of the interior of solid objects that are in contact with its transducer. Using a Schlieren system I was able to make the projected image visible.
Right after receiving the PhD degree in 1979, under an award from the US National Research Council, I came to the USA as a postdoc to work at the Air Force Materials Laboratory, Dayton, Ohio. I investigated the possibility to develop an ultrasonic analogue to the optical Schlieren method but ended-up discovering the polar backscattering (PBS) phenomenon in composite materials. Shortly before ending the first year as a postdoc I was hired by System Research lab (SRL) as a Senior Physicist that led the on-site R&D NDE contract with the Air Force. At the end of 1982, while using a Schlieren visualization system I discovered another phenomenon in composite materials – the Leaky Lamb Waves (LLW).
In 1983, I joined McDonnell Douglas, Long Beach, to lead the R&D NDE activity at the Long Beach, California facility. I continued working on both the LLW and the PBS phenomena in cooperation with researchers at UCLA, Texas Research Institutes as well as other institutes in the US and internationally.
My involvement with robotics has been an evolutionary process. After joining Jet Propulsion Lab, Pasadena, CA in 1991, I established an NDE Lab but in 1993 I begun to develop novel actuators and I named my lab the NDE and Advance Actuators (NDEAA) Technologies Lab as described on http://ndeaa.jpl.nasa.gov Two of the actuators that I worked on at that time include ultrasonic motors that operate at low temperatures and electroactive polymers (EAP) as artificial muscles for space applications. The first robotic device that I initiated was the multifunctional automated crawling system (MACS). This crawler is driven by three ultrasonic motors and it was designed with controlled adhesion using suction cups allowing it to travel on surfaces of aircraft structures. Since then, the subjects of my involvement have grown significantly resulting from the increased challenges that I dealt with and the growing number of opportunities that I was given from NASA, other government agencies, industry and others.
ARS: You are one of the leading pioneers in the development of artificial muscles. How did you get the idea to do this?
Bar-Cohen: In 1994, a former JPL chemist, Dr. Al Stigman, showed me a paper that suggests a strong elecrostriction effect in a -PMMA (one of the taxicities of Plexiglas) producing a level of 14.7% strain under electric excitation. I proposed to NASA to use this material for the development of artificial muscles but, unfortunately, the researchers who authored the paper made a very serious error in their measurements, where the produced strain is orders of magnitudes smaller. With no choice, I searched and identified alternative EAP materials that have emerged in the early 1990s but were not known widely yet. I started using 2 of these materials: (1) the ionic polymer/metal composites (IPMC); and (2) the dielectric elastomer EAP. The IPMC was produced for me by researchers from the University of New Mexico at Albuquerque, USA, and then from Osaka, Japan. For the dielectric elastomer EAP, I used the material that was reported by SRI International, USA. Even though these alternative EAP materials did not generate large force I was able to demonstrate novel devices that had great potential for NASA including dust wiper, 4-finger gripper and a robotic arm lifter. The device that received the most attention was the dust wiper that I adapted for the Nanorover, which was supposed to be flown to an Asteroid in a mission that was joint NASA and the Japanese space agency, NASDA.
The consideration to use my dust wiper was announced in a NASA Press Release that was issued in Feb, 1999 and it brought enormous media attention to the topic of artificial muscles. This NASA announcement was wonderfully timed with the 1st SPIE’s EAP Actuators and Devices (EAPAD) Conference that I initiated and held in March 1999. To jump start the field of EAP, I posed a challenge to the researchers worldwide – develop an EAP actuated robotic arm that would wrestle with human opponent and win. This conference received significant international attention and was the largest ever to be held on this subject. The interest in the subject of EAP begun growing and many scientists and engineers started making it as their career and also training students at various degree levels, including PhD. The potential of the field of EAP is now well recognized worldwide.
ARS: Can you tell us more details about the behavior fundamentals of electroactive polymers (EAP)?
Bar-Cohen: Electroactive polymers (EAP) are human made actuators that most closely emulate natural muscles. In response to electrical stimulation they either bend, stretch or contract with strain levels of many percents reaching and even exceeding the capability of biological muscles while exhibiting "live-like" behavior. For this response, they have earned the moniker artificial muscles. In an effort to simplify the understanding of their behavior, I divided these materials into two major categories based on their activation mechanism including ionic and electronic. The ionic EAP are materials that involve mobility or diffusion of ions and they consist of two electrodes and an electrolyte within the EAP material. The activation of ionic EAP materials is done by as low as 1-Volts and it generates mostly bending displacement. Examples of ionic EAP include Carbon Nanotubes (CNT), Conductive Polymers (CP), Ionic Polymer Gels (IPG), and Ionic Polymer Metallic Composite (IPMC). In contrast, the electronic EAP are driven by Coulomb forces. These materials produce much larger actuation force and they can be operated in open air without concern of dehydration. However, they require high voltages in the range of 30 -150 V/ m m and, when using reasonable material thickness, the voltage can be as high as thousands of volts. Under this category the following materials are included: Dielectric EAP, Electrostrictive Graft Elastomers, Electrostrictive Paper, Electro-Viscoelastic Elastomers, and Ferroelectric Polymers.
ARS: What do you see as main advantages of using artificial muscles and what are the weakest points to be solved?
Bar-Cohen: As actuators, these materials produce large strain and can operate mechanisms without the need for conventional components like gears, and bearings. They are light weight, operate quietly, are fracture tolerant, can be shaped as desired with properties that can be engineered, and they have many other advantages that are superior to traditional motors. However, the technology of making and using these materials is far from being mature. EAP materials are still producing a relatively low actuation force with conversion efficiency that is far from an optimum value. These materials are still not available as a standard commercial product and their properties are still insufficiently documented for engineers use.
ARS: Who or what could use the new artificial muscles and are there any commercial results?
Bar-Cohen: The technology of artificial muscles is in its emerging stages but significant advances have already been reported. There is one commercial product that appeared at the end of 2002 in the form of a robot fish made by Eamex, Japan. A video showing this robot fish can be seen on http://www.eamex.co.jp/video/fish.wmv This robot, which seems so realistic in the video, does not use battery to swim - it is driven by induction coils located at the bottom and the cover of the tank.
There are already several reported devices at the prototype stages including active audio speakers, catheter-steering element, miniature manipulator and gripper, active diaphragm, dust wiper, vein connectors for repair after surgery, smart prosthetics and others. Recent research at the Sungkyunkwan University, Korea, has led to the development of a series of interesting mechanisms and devices including a smart pill, which is made as a tube-like structure that performs inchworm motion for traversing thru the gastrointestinal track. These researchers are also de veloping an active Braille display for vision impaired following a concept that I described in my edited and coauthored book about EAP http://ndeaa.jpl.nasa.gov/nasa-nde/yosi/yosi-books.htm . The performance of the active Braille display is currently under evaluation, where blind patients are given patterns of letters and symbols and asked to recognize them. The use of dielectric elastomer EAP for such a display was also a subject of study at SRI International where a simple mechanism was constructed taking advantage of the large strain that is produced.
EAP materials are particularly attractive to biomimetics since they can be used to mimic the movements of humans, animals and insects for making biologically inspired intelligent robots. One of the great challenges to imitating biology is to create robots that mimic such creatures as octopus. This requires making robots that are highly flexible and dexterous that operate intelligently and autonomously with the capability to crawl through very narrow openings; camouflage the body by matching the colors, shape and texture of the surrounding; be equipped with multiple tentacles and suction cups for gripping objects; and having many other capabilities and multifunctional components that can perform multiple tasks simultaneously.
ARS: You have registered very impressive patents list. Before few months, you have patented the “Smart ultrasonic/sonic driller/corer”. What are the characteristics of this invention?
Bar-Cohen: Since starting to expand the research and development activity from the field of NDE, I tried to avoid “blinders”. With help from my group members as well as leading researchers and engineers worldwide, and as a result of “out of the box” thinking, I came up with numerous initiatives and inventions. As you can see from the list of my NASA New Technology Reports (submitted to JPL and NASA for consideration of filing patents http://ndeaa.jpl.nasa.gov/nasa-nde/yosi/yosi-ntr.htm), the range of topics of my activity is quite broad. The ultrasonic/sonic driller/corer (USDC), which I initiated and co-developed, received the 2000 R&D Magazine award as one of the 100 most innovative instruments. This device requires very low axial load to drill very hard rocks and NASA has significant interest in it because of it’s potential to operate from a relatively lightweight rover and at planets with a very low gravity. In the specific invention of the smart-USDC, which I have recently co-registered as a patent, we took advantage of the fact that the bit does not rotate allowing integration of such sensors as fiberoptics and thermocouples to make measurements and imaging inside boreholes.
ARS: Have any of your innovations been spun-off by NASA for commercial industrial use, or are they currently being used in space related applications?
Bar-Cohen: My NDE related inventions, particularly the polar backscattering and leaky lamb waves, have been used in various industries and also were the subject of research in many universities worldwide. The USDC and many of its spinoffs are being investigated at various levels of technology readiness including field test of a gopher that we developed for deep drilling of ice. This field test of the gopher took place from July 11 to 13, 2005. The medical devices, FMPUL, ULICH and the expanding catheter, received considerable interest from various medical organizations. Also, The piezopump had numerous inquiries and requests for evaluation towards potential use as a peristaltic pump.
ARS: Could you tell us something about your current research?
Bar-Cohen: Now, I am the supervisor of the JPL’s Advanced Technologies group and responsible for the NDEAA Lab. The topics of my research and development tasks are mostly described in websites that are links of my webhub http://ndeaa.jpl.nasa.gov Overall, my group is producing novel mechanisms and instruments for space exploration including sample acquisition and handling, multi-radiation source, and many others. Also, we are providing expertise to support the development of electroactive materials actuators, particularly piezoelectric, for NASA applications. Further, I am acting as the unofficial mentor for the worldwide development of EAP.
ARS: Six years ago you challenged scientists to create an artificial arm that could beat a human in an arm-wrestling match. The catch was that arm must be made of a pliable plastic material controlled by electrical impulses. The man vs. machine first showdown occurred on March 7, 2005 as part of the 2005 SPIE Annual International EAPAD (EAP Actuators & Devices) Conference in San Diego. Have you expected such a “fast” respond?
Bar-Cohen: Given the level of capability in 1999, I thought it would take many years before such a contest will take place. To make robotic arms that most closely simulation human arms, I suggested that the structural parts of the robotic arms will be produced from plastic. For the first competition, I relaxed this suggestion from a requirement to preference in order to encourage greater number of participants who would use EAP as actuators for the contest. In 2003, I had the first surprise when scientists from SRI International informed me that they believe they reached the level of progress that they may be able to make such an arm. However, due to cost limitations they did not follow up with an actual arm development. This notification made me prepared to the possibility that we may see a contest sooner than later but I was not sure when. Amazingly, this year we had the readiness of three arms that were driven by very different EAP materials. Before the contest begun on March 7, I did not know what to expect. While I had general information about the arms and their drive actuator, until the contest took place I had no idea how good these arms will perform.
ARS: All the three robotic arms have lost the “fight” but they are actually winners because this match attracted big publicity. Was that your primary intention?
As you noted, while the 17-year old female student won against all the three robotic arms, the field of EAP won enormously since the contest helped making advances towards the following goals:
* Promote advancements towards making EAP actuators that are superior to the performance of human muscles
* Increase the worldwide recognition of EAP materials as artificial muscles
* Attract interest among potential sponsors and users to the possible benefits to commercial products, medical devices, military applications and many others.
The participating robotic arms were made by:
* Environmental Robots Incorporated (ERI), Albuquerque, New Mexico, USA.
* Swiss Federal Laboratories for Materials Testing and Research, EMPA, Dubendorf, Switzerland
* Senior Students from the Engineering Science and Mechanics Dept. Virginia Tech, USA
The longest to hold against the student has been the arm from ERI and it lasted for 26-seconds, the 2nd lasted 4-seconds and the 3rd lasted 3-seconds. To get a prospective to this significant achievement it is important to remember that the first human flight by the Wright brothers before over hundred years lasted only 12-seconds. Initially, the challenge is to win against a human (any human) using a simple shape arm but the ultimate goal is to win against the strongest human on earth using as close resemblance of the human arm as possible.
ARS: In your book “Biologically Inspired Intelligent Robot” you wrote: Putting functional reasons aside, there is another motivation to build robotic creatures - to better understand ourselves. It is a very interesting idea, could you explain it?
Bar-Cohen: Such robots are supposed to operate as artificial creatures with capabilities, characteristics and behavior that are very much life-like. As we learn their potential and what we can use them for, such robot will increasingly evolve to reach performance that may even exceed our capabilities. So, just like discovering a new animal, we will need to determine, what is possible, acceptable, ethical, feasible, and preferable as well as what are other features that would be desirable to do with such robots. As we improve our understanding of biologically inspired robots we will also understand ourselves better. Moreover, we will be able to use such robots in the treatment of humans with psychological problems. As we have more people interact with the society thru the internet there will be an increasing loss of traditional human interactions and we may need to develop methods of teaching social skills. For this purpose, human-like robots may be used to simulate real humans’ response and behavior in various simulated scenarios using what we will increasingly learn about ourselves.
ARS: Biomimetics has woken an interest in more life-like robots. How do you estimate the future trends in this field?
Bar-Cohen: As the field of robotics evolves we find increasing number of science fiction concepts becoming engineering reality. However, the movie industry created a “picture” of robots that is still far beyond what is doable. In recent years, enormous progress has been made in producing human-like robots and increasing major manufacturers (e.g., Sony, Honda, and Mattel) are producing toy robots with such characteristics. A notable example of this progress includes an android head made by David Hanson from the US (not using EAP yet) that appears, speaks, recognizes speech and makes facial expressions just like Philip Dick, who is the author of the science fiction books Blade Runners, Minority Reports and others. A video review of his developed android heads can be seen on http://hansonrobotics.com/movies/sci_ch_NeXtFesT.asf
As the possibility to make live-like robots improves, I believe we will see the technology in use everywhere in our life. This may include their use to perform tasks that are too dangerous for human operation; use robots in industries where it is too expensive to operate by humans or simply suffer from a lack of people (a situation motivating the development of nursemaid robots in Japan); as well as performing tasks that combine the advantages of several biological creatures in hybrid form, as well as operate as human companions or assistants.
ARS: Recent developments in this field lead researchers to believe that the idea of a bionic man or woman may someday be possible. How real is it and when can we expect the first “Terminator” on the street?
Bar-Cohen: EAP as artificial muscles may find applications in support of humans’ external and internal body functions. As external actuators, they may be used to construct exoskeleton and limb assisting devices, while internally they may be used to replace or augment real muscles. The developed devices and mechanisms may equip human users with capabilities that may make them superior to unaided humans or even possibly making them as bionic humans.
In raising this question you have actually touched on a bigger issue -- Making biomimetic robots requires attention to technical, philosophical, and social issues since we are effectively creating an electro-mechanical analog of biological cloning. The topic of making such clones may rise to a level of public debut in the coming years, maybe to the level that was recently seen for the topics of fetal stem cells and human cloning. As biomimetic robots with human characteristics are becoming more an engineering reality there may be a growing need to equip them with limited self-defense and controlled-termination. In parallel, there may be a rise in potential use of such robots for unlawful applications, and proper attention may be required by lawmakers’ to deal with such a possibility in order to assure that they are used for positive applications. As this need begins to rise, it will become more important to give serious attention to Isaac Asimov’s laws that he defined for robots in 1950. These laws are addressing the concern to humanity from the danger that robots may be designed to harm people. The desired status of robots according to these laws is to assign them the role of slaves to humanity, where they are allowed to protect themselves only as long as no human is physically hurt. While these laws reflect the desire to see “peaceful” robots as productive support tools it might not be realistic to expect them to be designed only as obedient robots. One would expect that some robots would be designed by various governments to perform military and law enforcement tasks that may involve violation of these laws. As in other human made tools, these robots can find positive or negative applications and it is up to us to direct their development to positive use.
For more information:
Artificial muscles
http://eap.jpl.nasa.gov
Books and proceedings for which I am an editor
ttp://ndeaa.jpl.nasa.gov/nasa-nde/yosi/yosi-books.htm
WW-EAP Newsletter
http://ndeaa.jpl.nasa.gov/nasa-nde/lommas/eap/WW-EAP-Newsletter.html
EAP Conferences
http://ndeaa.jpl.nasa.gov/nasa-nde/lommas/eap/eap-conferences.htm
Companies that make EAP
http://ndeaa.jpl.nasa.gov/nasa-nde/lommas/eap/EAP-material-n-products.htm
The competition
http://ndeaa.jpl.nasa.gov/nasa-nde/lommas/eap/EAP-armwrestling.htm
* The competing arms
http://ndeaa.jpl.nasa.gov/nasa-nde/lommas/eap/amerah/robot-side-of_AMERAH.htm
* The 17-year old student
http://ndeaa.jpl.nasa.gov/nasa-nde/lommas/eap/amerah/the-human-opponent.htm
Jet Propulsion Laboratory / Caltech, Pasadena, USA
Published in: Volume 2, Number 3, September 2005
For further informations in German please click here!