There has been dramatic reduction in costs for computing, networking, and sensor technologies. At the same time, the performance has gone through unprecedented improvements. The convergence of these technologies is leading to significant changes in all aspects of our lives. This blog is focused on discussing off-beat ideas that are attempting to reshape engineering and education.
Newton’s scientific accomplishments are truly astonishing. One of his remarkable theories stated that light has momentum. If light has momentum, then it should be possible to move objects by shining a light on them. I am sure that it sounded like a crazy idea when Newton first proposed it.
Over the years, people have done numerous experiments to confirm this theory. This idea is so captivating that it even influenced the great George Lucas. Star Wars movies featured famous Lightsabers that utilized the special properties of the light to create a powerful Jedi weapon. But we have not seen such fantastic spectacles of light and matter interaction in our everyday macroscale world. Light has very small momentum. So moving a heavy couch by shining a laser on it remains in the realm of science fiction. Unfortunately, if you make the laser too powerful, it will simply evaporate the couch and set your house on fire.
A different picture emerges at the microscale. It is certainly possible to move tiny objects by shining a laser on them. But this mode of interaction does not offer much control. Ashkin in 1986 figured out a better way. He created optical traps that were able to hold tiny particles in place. The basic idea was to bend and focus a laser beam tightly using an objective lens. Once the object enters the laser beam, the laser starts interacting with it and pushing it towards the focal point where it gets trapped.
We can imagine the laser as a collection of rays. These rays are reflected and refracted by objects that intercept them. As the rays are bent, their momentum changes and they exert force on the object. This phenomenon can be visualized as interactions between a stationary ball and a moving ball. The direction of the motion of the moving ball changes as it strikes the stationary ball. Hence it exerts a force on the stationary ball. Ashkin found out that once the effect of all the rays in the laser beam was accounted for, the direction of the resultant force was such that the object was pushed towards the focal point of the beam. So as the object entered the laser beam, it was simply pushed towards the focal point and once it reached that point it remained there. In essence, the focused laser beam created a particle trap. A trapped particle can be moved by moving the laser beam. Thus, the laser has been turned into a tweezing tool for grabbing small particles and moving them. Moving optical traps are often referred as optical tweezers. Numerous groups have used optical traps to manipulate biological cells and study them. In fact, many important discoveries in biology have been made using optical traps. Biologists are primarily interested in fundamental scientific discoveries. So they are happy to create and move optical traps using tele-operation. Just like tele-operated robots, tele-operated optical traps have many inherent limitations. They are slow, require significant expertise, and limit what kind of manipulation is possible.
I was introduced to optical tweezers in 2004 during my sabbatical at the National Institute of Standards and Technology. Thank you Arvind Balijepalli and Tom LeBrun! I am interested in robotics. So once I learned about optical traps, I became interested in turning them into robotic hands for automatically manipulating biological cells. In many situations, directly trapping biological cells can cause complications. Cells might have an irregular shape and they might be susceptible to damage due to direct exposure to the laser.
We decided to take a different path. Rather than building robotic optical tweezers, we wanted to build robotic optical hands. The idea was to use the laser to trap and move microspheres made out of silica or polystyrenes. These microspheres can serve as “fingers” for gripping or pushing cells. So in our idea, the laser would act as an optical hand (i.e., hand of a ghost) and microspheres would act as “fingers”. This idea enabled free floating “fingers” with no physical hand attached to them. This would be truly an alien hand with no biological counterpart on Earth! We could have as many “fingers” as we wanted by splitting the laser beam to create multiple traps. We could also have multiple hands if we wanted! It was a crazy idea. But it removed many constraints associated with conventional microscale robotic grippers and offered several new possibilities. Soon we were hooked to make this idea a reality.
There were numerous challenges. Microspheres and cells float in the liquid medium and exhibit Brownian motion. We had to detect these objects in the scene, plan the next trap location, and make sure that microspheres and cells moved the way we wanted them to move. However, we only had a few milliseconds to do image analysis, planning, and control. Images are noisy and the environment has significant uncertainty. Moreover, the motions of all the hands and fingers need to be exquisitely coordinated. So this was a really tough robotics problem. +ashis banerjee , +Sagar Chowdhury , +Petr Svec , and +Atul Thakur worked incredibly hard to solve the challenging planning, perception, and control problems to realize this vision. They built upon the basic software capability provided by Andrew Pomerance. Wolfgang Losert and Chenlu Wang provided valuable help in conducting the experiments. Thank you National Science Foundation for supporting this work! Our adventures in this area began by concurrently trapping multiple microspheres and moving them into an ensemble. We then used that ensemble to hold a cell and move it. We also developed the capability to move the cell into its desired location by pushing on it using a microsphere. If a cell is very sensitive to the laser, then we can use an intermediate microsphere as a tool, so that the microsphere “finger” being trapped by the laser does not touch the cell and ensures physical separation between the cell and the laser. Please see below the video of our robotic optical hand.
Hopefully, our colleagues in biology and medicine would be able to think about new scientific theories that can be enabled by the above described robotic optical hands and their variants. Possibilities range from understanding the behavior of cancer cells to understanding how cells communicate.
Robotics solutions that enable precise automated manipulation of individual cells are expected to revolutionize medicine and biology. Our explorations in this area have taught us that robotics at the microscale requires out-of-the-box thinking. We are now busy coming up with even crazier ideas to marry robotics and biology. So stay tuned for updates.
Industrial robots (e.g., ABB, PUMA) have been quite successful in mass production assembly lines. For example, they are routinely used to weld, paint, and join parts in automobile industry. However, small and medium manufacturers (SMM) in the US have largely stayed away from using industrial robots. They continue to rely on manual labor and this makes it hard for them to compete with overseas suppliers with low labor costs.
The National Association of Manufacturers (NAM) defines small manufacturers as companies with 500 or fewer employees and medium-sized manufacturers as companies with 2,500 or fewer employees. The NAM estimates that that the US has close to 300,000 SMM, representing a very important segment of the manufacturing sector. As we move towards shorter product life cycles and customized products, the future of manufacturing in the US will depend upon the ability of SMM to remain cost competitive.
This blog post explores the reasons behind the lack of adoption of industrial robotics technology by SMM and recent advances in robotics that might change the status quo.
Let us explore a representative scenario to understand the limitations of the current industrial robots and why they are not used by SMM. Imagine that you are working in a small company and building a prototype of new medical device. You are under extreme time pressure to meet an important deadline. As you are assembling the device, you realize the bracket is too compliant. You need to laser cut it again in a much stiffer material. The good news is that it will only take six minutes to cut the bracket. But the logistics associated with it will take an hour. You really need to continue assembling the rest of the assembly and testing the controller. You simply don’t have an hour to spend and can certainly use an assistant right now!
Here is what you would like your assistant to do - walk over to the material storage area, locate the right material, pick up the material, take it to the laser cutter, open the laser cutter, place the material in it, press the button to start cutting, wait for the part to finish, open the laser cutter, pick up the part, clean it, and bring it to you. Obviously human assistants can do all of these tasks without even flexing their cognitive muscles. I am sure that they can do all of these tasks while texting and surfing the net on their smart phones! Unfortunately the current industrial robots simply cannot do these tasks. So you simply cannot get a robot assistant today!
Robots that rule the assembly line have the following four limitations. First, they are immobile. They cannot go to the task location. The work has to be brought to them. Second, their dexterity is extremely limited. Simple tasks such as opening shelves and precisely placing and securing a previously unseen part in a machine are out of their capabilities. Third, it takes a long time to program them. So using robots on no-repetitive tasks is simply counter-productive. Finally, robots cannot work in the close proximity of humans because of safety concerns. So you can forget about a robot assistant walking over and handing you a tool or a part to assist you on the shop floor.
Most SMM use highly automated machines (e.g., CNC machines, laser cutter, water-jet cutters, CNC press-brakes, 3D printers). However, SMM shop floors tend to be unstructured and often go through changes to meet the needs of the projects at hand. Main sources of manual labor in SMM are material transport and handling, machine setup and calibration, inspection, clean-up, and packaging. Unfortunately, the current industrial robots that are designed for mass production assembly lines are of not much use in these tasks. So industrial robots offer very little value to SMM!
Recent advances in robotics are challenging the status quo and aiming to turn robots into important tools for SMM. I would like to share the following important trends:
Mobile manipulators are robots that can transport themselves to the work site. I recently saw demonstrations of mobile manipulators developed by Kuka that show impressive capabilities. This capability will be very useful in expanding the role of robots in manufacturing, particularly from the SMM point of view.
Dexterity has been a major obstacle to the widespread use of robots in manufacturing. Recent developments on robot hands are targeting to overcome this obstacle (e.g., Schunk and Barrett hands). 3D printing enables users to quickly create their own customized grippers in few hours.
Baxter from Rethink Robotics is aiming to eliminate the need for writing code to program robots. Instead, robots can be programmed by demonstrating the tasks. This is expected to empower workers on the shop floor. They will be able to start utilizing robots without the need to wait for a robot programmer to assist them.
Recent advances in human-safe robots are enabling robots to work in the close proximity of humans.Kuka lightweight arm and Baxter are representative examples of advances in this area. Many researchers are developing methods to track human operators in the workspace to make robots aware of humans in the workspace and change planned robot motions to avert injury to humans. For example, +Krishnanand Kaipa , +Carlos Morato , and +Boxuan Zhao in my lab have developed a system to monitor a human operator working in the close proximity of a robot using four Microsoft Kinect sensors. This information is used by the robot to update its plan. The video of this system is shown below.
I believe that ultimately the convergence of the above mentioned technologies will create the second generation of industrial robots that will revolutionize the manufacturing industry. Once the demand increases for these robots, the cost for them will start coming down. There is no reason why low-end industrial robots cannot be sold for less than ten thousand dollars once the economy of scale kicks in. This in turn will make robots affordable for SMM and manufacturing cost-competitive in high wage countries.
I have always been fascinated by birds. To me they represent beauty, freedom, and a design marvel. I am envious of bird watchers. What a wonderful hobby! Bird watching requires patience and traveling to exotic places where birds like to hang out. Unfortunately patience is not my forte. Also, at this stage in my life I am unable to travel to exotic places. So for now,I have compromised and have settled for the next best thing - creating and watching my own “birds”. I am interested in building robotic birds, not the kinds that look pretty on the shelf, but the ones that can actually flap their wings and fly. Eight years of experiments have taught me that designing and building robotic birds is hard, despite the apparent simplicity of the idea - flap wings to generate thrust to propel forward and use the moving air to generate lift to stay afloat. I am glad that this looked deceptively straightforward in the beginning; otherwise we would have never started on this adventurous journey. How hard can it be to build two wings and flap them using a motor? It turns out to be quite challenging if you want the bird to actually fly! This requires a long trial and error process due to the absence of accurate simulation tools. Many concepts that look good on the paper lead to a spectacular crash during the flight test, often causing a fatal injury to the robotic bird! So design iterations are painfully slow.
We had the first successful flight in 2007. +Arvind Ananthanarayanan, Wojciech Bejgerowski, +Dominik Müller were the main architects behind this feat. Hugh Bruck, my faculty colleague at the University of Maryland, offered valuable help with the wing evaluation. We subsequently created three more flying versions using similar ideas. The last one in this series was completed in 2010. John Gerdes played a major role in building the last version in this series. Please click here to see videos of these “birds” in action. We were able to put a tiny video camera on them and get the “bird’s eye view”. We were able to launch them using a small ground robot. They were able to fly in moderate winds of around 10 mile per hour. As I mentioned before, every design flaw led to a fatal crash. But to our surprise, a very successful design also led to a fatal crash for our “birds” for a different reason. A hawk felt threatened by our "bird" and tore it apart in the mid-flight on multiple occasions!
Real birds are able to precisely control each wing during flight which enables them to do all sorts of aerobatic maneuvers. This has been a very difficult feat to achieve in bird-inspired robots. In fact, prior efforts (including our own mentioned above) utilized only simple wing motions where both wings are driven by a single motor. So motions of two wings are coupled. Minor adjustments can be made in wing motions by using small secondary actuators. But two wings cannot move completely independently. In the past, any major change in the wing motion had to be accomplished by doing a hardware change on the ground. Clearly this limited how close a robotic bird came to the real bird in terms of the flight characteristics.
I wanted to build a bird with completely independent wings that can be programmed with any arbitrary motion profiles. We did a preliminary experiment five years ago, but unfortunately it was not successful at that time. So we shelved the idea for few years. Hugh Bruck and I revived the idea again about a year ago. I am happy to report that we finally had a breakthrough last week. The students responsible for this success are Eli Barnett, John Gerdes, Johannes Kempny, Ariel Perez-Rosado, and Luke Roberts. Our new robot is based on a fundamentally new design concept. We call it Robo Raven. It features programmable wings that can be controlled independently. We can now program any desired motion patterns for the wings. This allows us to try new in-flight aerobatics that would have not been possible before. For example, we can now dive and roll. Please see below for the video of Robo Raven.
The new design uses two actuators that can be synchronized electronically to achieve motion coordination between the two wings. The use of two actuators required a bigger battery and an on-board micro controller. All of this makes our robotic bird overweight. So how do we get Robo Raven to “diet” and lose weight? We used advanced manufacturing processes such as 3D printing and laser cutting to create lightweight polymer parts to reduce the weight. However, this alone was not sufficient. We needed three other tricks to get Robo Raven to fly. First, we programmed wing motion profiles that ensured that wings maintain the optimal velocity during the flap cycle to achieve the right balance between the lift and the thrust. Second, we developed a method to measure aerodynamic forces generated during the flapping cycle. This enabled us to quickly evaluate many different wing designs to select the best one. Finally, we had to perform system level optimization to make sure that all components worked well as an integrated system.
Robo Raven will enable us to explore new in-flight aerobatics. It will also allow us to more faithfully reproduce observed bird flights using robotic birds. I hope that this robotic bird will also inspire more people to choose “bird making” as their hobby!
Robotic birds (i.e., flapping wing micro air vehicles) are expected to offer advances in many different applications such as agriculture, surveillance, and environmental monitoring. Robo Raven is just the beginning. Many exciting developments lie ahead. The exotic bird that you might spot in your next trip to Hawaii might actually be a robot!
Clouding computing is inspiring roboticists worldwide to break the mold on traditional robots and harness the power of clouds to create the next generation of robots. This new exciting development is being called cloud robotics. In my opinion, this development is very timely and not coincidental. As humans we are increasingly keeping at least a part of our brain in the cloud. You have outsourced a brain function to the cloud, if you
used Facebook to remember your friend’s birthday;
used iPhone app to get directions to your favorite restaurant;
used Wikipedia to recall the name of the fourth Beatle;
used Google to search recipes for making cheese sandwiches.
So why should robots not follow this trend? The cloud computing promises the following three major advances in the field of robotics.
Once the robot brain lives in the cloud, design constraints fundamentally change. Robots can have practically unlimited computing power. It eliminates design constraints and gives tremendous freedom to robot designers. I will list a few noteworthy opportunities. Performing faster than real-time high-fidelity simulations to aid the plan generation is currently an unrealizable goal using on-board computers. Two of my students, +Josh Langsfeld and +brual shah tell me that this is now practically within our reach using the cloud. We do not need to add unnecessary weight on the robot to protect its brain. Robots can be made really small if they don’t need on-board powerful computers. Hopefully, they will consume a lot less power and can work a lot longer on single a battery charge. As you can imagine, suddenly the world is full of new design possibilities!
Robots can access large databases (e.g., maps, images, videos). We may need to build different interfaces so that robots can use web to search and understand results they get back. But there is no reason why a robot should not be able to access Google, Facebook, Wikipedia, YouTube, and OSRF Blog.
As new information is discovered, it becomes instantly available to robots. This facilitates new modalities for operation of robot teams. If a robot learns a new skill, all robots with similar capabilities would be able to use that skill. I am sure that this last capability will make us human quite jealous of robots. Won’t it be nice if you are able to use the cool new golf swing the moment your friend masters it after spending three weeks in the miserable heat to learn it?
Many different kinds of robots such as self-driving cars, robot swarms, and healthcare robots can potentially benefit from cloud robotics. But there are three main challenges in embracing cloud robotics and using it in practice.
Using the cloud as the brain requires connectivity to the cloud. What happens if the connectivity to the cloud is poor or lost? We certainly will need to make sure that the robot will have on-board “little brain” to make sure that they remain safe while they are unable to use the “big brain” that resides in the cloud. We will need to figure out the coordination between two brains.
What happens if the cloud is hacked? Hackers could deliberately send malicious information or instructions to robots. How can a robot know if the information coming from the cloud is reliable or not? We will need to figure out new ways to authenticate information coming from the cloud to ensure that robots and people around them remain safe despite threats of compromised clouds.
Unwanted software upgrades are painful for many humans (this one of my pet peeves!). When you use the cloud, you have virtually no control over what gets upgraded and when it gets upgraded. Unfortunately, a really small change in the information structure might pose a big problem for robots. We will need well-defined semantics to exchange information with robots and will need to hope and pray that cloud providers are kind to our robots as they plan software upgrades. I am normally not worried about a robot rebellion. But unwanted software upgrades might push robot to rebel against humans.
I would like to hear your thoughts on how cloud computing will affect the field of robotics. Are we ready for cloud robotics?
I spent the summer of 1987 being an intern at a leading truck manufacturing factory in India. Every day as I walked around the factory floor, I saw machines giving “birth” to new parts. This was the beginning of my fascination with manufacturing and automation technologies.
The field of manufacturing gives humans the capability to make things that do not exist in the natural world. All comforts of the modern life can be directly or indirectly attributed to manufacturing. I believe that automation augments human capabilities and allows us to realize more with less human effort and so the standard of living rises for everyone.
This post is focused on the manufacturing innovations in the last twenty five years and their impact. I would like to set the stage by first reviewing six notable limitations and constraints that existed in late eighties despite remarkable advances in manufacturing enabled by the use of robots, numerically controlled machines, and computers.
First, it took days to program robots and machines. It took even longer to debug those programs to make sure that they did not cause any accidental damage. Going from engineering drawings to physical parts took weeks if not months.
Second, if you were an inventor with a brilliant idea living in a small town, you had to physically travel to the nearest city that had an advanced manufacturing facility. So the access to the advanced manufacturing was limited.
Third, you would not use words “affordable” and “advanced manufacturing” in the same sentence unless you were telling a joke. The access to the advanced manufacturing required major capital investments.
Fourth, advanced manufacturing consumed a lot of energy and generated unwanted emissions and waste.
Fifth, your material choices were limited unless you had a multi-million dollar development budget. You simply could not open a catalog and find lightweight, thermally conducting, and electrically insulating material.
Finally, operating an advanced manufacturing facility required significant human expertise. For example, robots and machines had to be manually programmed using low level languages. You needed experienced operators to “babysit” machines and robots and be ready to hit emergency button if things went wrong.
The above described limitations and constraints had significant impact on the innovation process. It impacted who could participate in it, what kind of innovation could be realized, how long it would take to bring a new innovation to the market, and how much the resulting products would cost.
Many manufacturing innovations have emerged in the last twenty five years to address the above described constraints and limitations. The following eight, in no particular order, are my personal favorites:
3D Printing: 3D printing (AKA additive manufacturing) allows converting 3D CAD models into physical parts automatically. It does not use part-specific tooling or setup. It can make very complex shapes and can be operated with minimal expertise. Designers are now able to access 3D printing processes over the Internet. Please see an earlier post for more details on 3D printing.
Second Generation Industrial Robots: The use of the first generation industrial robots was confined to simple tasks (e.g., welding, painting) on production lines. They were fixed in a cage and isolated from human workers to prevent injuries. Recent advances in robotics are fundamentally changing these norms. Mobile manipulators can go to workpieces to work on them. Dexterous hands enable robots to work on complex tasks. Robots can program themselves by observing human demonstrations (e.g., Baxter from Rethink Robotics). Safe Robots with novel safety features have been developed that enable human and robot collaboration on manufacturing tasks. Please see another post for more details on these developments.
Low Cost Laser Cutters: One can get a brand new laser cutter for less than $10K and can use it to go from a CAD model to a physical part in a matter of minutes for reasonably complex geometries. Currently this technology is limited to mainly cutting two-dimensional shapes. I would also like to mention waterjet cutters that can cut a wide variety of materials and can easily cut through several inches thick steel. Both of these processes are quite accurate, extremely simple to use, and can be setup in less time than perhaps what will take you to read this post. Please see another post for more details on this development.
Micro Manufacturing: Advances in manufacturing at small scale, especially micro molding and silicon micro machining have produced sensors and devices that are low-cost, small in size, energy efficient, and fast. These have helped in reducing the cost of manufacturing equipment and also led to many new products.
Internet-Based Manufacturing Services: Today, if you have Internet connection, you have access to manufacturing facilities. You can directly order parts from manufacturers (e.g., www.protomold.com), let a broker find you a manufacturer (e.g., www.mfg.com), work with a representative for manufacturers (e.g., www.quickparts.com) on the Internet. Please see another post for more details on these developments.
Desktop Virtual Manufacturing: The cost of computer-aided design and manufacturing has come down dramatically and these software tools can be used to speed up the manufacturing plan generation and simulate the manufacturing system before making the part. We have reached a point where we no longer need to do physical dry runs for programs and “babysit” machines and robots.
Green Manufacturing: Recent advances in manufacturing have significantly reduced the energy consumption (e.g., electric injection molding machines) and reduced negative environmental impact (e.g., coolant free dry machining).
Polymer Composites: By mixing polymers with micro and nano scale ingredients, new materials are being created that have remarkable properties. The ability to injection mold these polymer composites is reducing the processing cost and making polymer composites an economically viable option over metals in many applications. This development has created many new options for designers.
The purpose of this post is to celebrate ground-breaking manufacturing innovations that are reshaping the industry. But the limitations that I identified above still exist in many segments of manufacturing industry. Moreover, what appears to be a norm today is likely to appear a major limitation in the future. So we have to continue advancing the frontier.
I have shared my personal favorites based on my own biases and experiences. What are your favorite manufacturing innovations? I look forward to your comments.
