The obvious thing to measure is motor speed.  That part is easy.  Servo motors have built in feedback devices. In the old days, the preferred feedback device was a small generator that produced a voltage proportional to the speed.  In the digital age feedback is by quadrature encoder that outputs a digital pulse that is primarily used for position control.  Most control systems are able to easily integrate the pulse train to derive the speed of the motor.

Unfortunately, most applications require relatively low speed.  Most motors are engineered for high speed.  This is in an effort to package more work related power in a smaller physical package.  Often, the motor is connected by pulleys or gear reducers to get the speed of the motor to more closely match the desired speed of the load.

Some of the important attributes of motion cannot be easily measured.  In addition to speed, torque is extremely important to controlling motion.  Torque can be measured directly from the drive electronics, but this is rarely used for control.

Torque and current are direct equivalents with a slight variation due to the temperature of the motor winding. As the temperature of the motor goes up, the resistance goes up and the current required goes up at the same time.  Since high performance motors have fairly high internal temperatures, this swing can be in excess of 100 degrees centigrade, and should be considered in the control scheme.

Most of the emphasis on current control is in terms of protecting the motor and drive electronics.  The first derivative of current over time  is the limiting parameter of the power electronic devices and is an important boundary condition in safe operation of the electronics.

More important information can be derived by considering the region of the motion profile and the current or torque requirements that are presented.  In order to accelerate a load, a lot of current is needed to overcome the mass of the load.  But once the load is moving the torque requirement drops off.  This creates an opportunity to profile the current requirement while using the conventional error detection scheme of the traditional control.

Other variable that are part of the mechanical system are things like momentum and center of mass.  In multi-axis mechanisms, there is usually a dependency of one axis upon another.  The idea that the mass of one axis is changing it’s center of mass and momentum with respect to the other axis is generally ignored.  This too is an opportunity to gain increased stability in the control and possibly improve throughput by having a better model of the application from which to create the ideal control.

Looks to me like there is a lot of room for improvement.  Let me know if you agree or disagree.

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The damage is the result of natural forces that are beyond the ability of designers to engineer against.  And how we take heed of these events, or even if we take heed, may be the real measure of progress in western civilization.  The future of nuclear power plants is going to have include choices and alternative technology.

A nuclear power plant is a complex system, mostly controlled by technology from the process industry because it creates steam to drive a turbine which turns a generator.  The generator is a classic electric motor run in reverse to create electricity from torque.  So there is mechatronic technology involved in the process itself.

Even more mechatronics content is involved in the creation of the fuel and the operation of the control rods in water cooled reactors.  Robots are also frequently used in the processing of the fuel into the final shape for use in a reactor.

But the bigger question is what are the technology choices for nuclear power generated electricity that can survive the forces of natural disasters?  Interestingly, there are a number of mini reactor technologies that because of their small size, are much more likely to withstand the forces of nature.  Just Google mini nuclear reactors and you will find pages of information.  And discussions of numerous technologies that are competing for use in the power industry.

Large water cooled reactor have been producing electricity for 40 years or more.  But these designs are massive and susceptible to failure when the water flow is interrupted.  Which is what we have going on in Japan.

There are wave reactors, Thorium reactors, small water cooled designs and pebble bed reactors.  Each technology working its way through the torturous process of qualification for use by federal regulators.

Some of the technology is unproven and controversial.  But since I have seen the pebble bed reactor demonstrated, for me this is a leading edge technology.  The pebble fuel is a small .5mm diameter pebble of uranium contained in layers of graphite and ceramic.  By spacing the fuel apart in small bits, it cannot reach thermal runaway, and in fact, using helium coolant, the system can reach thermal equilibrium at 800 degrees.  Since the ceramic insulator is designed to withstand temperatures of 3000 degrees, there is little chance of the fuel melting the insulator and creating a runaway chain reaction.  Safe, small.  The American Nuclear Regulatory Commission attended a demonstration of this technology years ago.  I saw the video.

So the question is, when are we going to see some progress?  At the rate our government chooses to do things, it will take years.  At the risk of being redundant, providing electricity shouldn’t be about politics, it should be about free markets, and doing things right.  If the electric power industry is going to be regulated by politicians, then politicians need to be doing the people’s business and getting it done.

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Since the Second World War, manufacturing employment has dropped steadily from 33% of all employment to about 10% of all employment.  What is really interesting about this trend is that the total output of manufactured goods has remained roughly constant.  What accounts for this is increasing productivity.  And in recent years a lot of that productivity has been from automation.

The same Department of Commerce research shows agricultural employment, typically a very high labor area, dropping from 33% to 2-1/2% from the turn of the century, 1900′s, to the present.  And similarly, agricultural output in the US has remained constant.  The main force behind the reduction in labor has been the mechanization of agriculture, or as I would like to refer to it, the “mechatronic-ization” of agriculture, if that doesn’t butcher the English language too severely.

Mechatronics is that elastic term that takes into account so many disparate technologies.  Putting a hydraulic system on a power take off from the gasoline engine on a tractor in order to power a variety of farm implements is mechatronics at its finest.  And the dawn of factory robotics in the 1980′s has lead to production welding robots that cost less than $50,000.  So people are being freed from some of the more repetitive tasks required at the factory level, and, I suppose, being replaced by automation.

The dilemma becomes, how do we create new jobs.  Many people believe that the “Green Revolution” will create a lot of new employment.  Personally, and after much review of industry studies, there are jobs there, but not enough to turn the economy around anytime soon.  And frankly, most of the green power generation technologies have failed to meet their economic burdens, so it’s a work in progress.

On the other hand, the same ingenuity that led to robots on the assembly line in Detroit has also provided us with 3D solid printers that produce very high quality parts in small batches at very low cost.  Another mechatronic triumph.  Three axes of stepping motors using belt drives and rod bearings to move a print head in 3D that dispenses a variety of hot melt plastic materials into solid shapes following a computer program for a 3D part.

This technology drastically reduces the major hurdle of new product development, which is the cost of prototyping.  Hmmm.  Sounds like an opportunity.  And it is.

So maybe the key to increasing employment is new solutions to old problems.  Reinventing the means of production in every industry should be a powerful stimulus to innovation, invention and economic growth.  Let’s hope so.

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The Land Crawler xTreme robot offers its master a ride on top of  its square platform top, provided you don’t weigh more than 175 pounds. As it ambles around, it definitely doesn’t look like the smoothest or speediest way to get around the place, but it sure has got plenty of style doing it.

Funny thing is the maker of the robot says he made the Land Crawler eXtreme as a toy for his 2-year old son because he told him that he wanted to ride on a robot. Why couldn’t we all have dads who were that handy with robotics?

technabob.com

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Here we find a completely different approach to a universal gripper. Individual fingers are replaced by a single mass of granular material that, when pressed onto a target object, flows around it and conforms to its shape. Upon application of a vacuum the granular material contracts and hardens quickly to pinch and hold the object without requiring sensory feedback.  The volume changes less than 0.5% suffice to grip objects reliably and hold them with forces exceeding many times their weight.

The universal gripper utilizes ground coffee beans inside of a balloon.  The coffee beans offer an interlocking grain that proved better than other materials tested that ranged from sand to ground rubber tires.

The Universal Gripper uses ground coffee beans inside of a balloon

Veiw full photo gallery here

The operating principle is the ability of granular materials to transition between an unjammed, deformable state and a jammed state with solid-like rigidity. They delineate three separate mechanisms, friction, suction, and interlocking, that contribute to the gripping force. Using a simple model we relate each of them to the mechanical strength of the jammed state. This advance opens up new possibilities for the design of simple, yet highly adaptive systems that excel at fast gripping of complex objects.

Universal Gripper Demonstration

Universal Gripper Pouring Water

www.pnas.org

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Clean rooms are classified according to the number and size of the particles permitted per volume of air. For example, a Class 10 clean room denotes that no more than ten particles of 0.5 µm or larger and zero particles of 5.0 or larger are permitted per square foot of air. Contaminants come from people, process, facilities, and equipment. In order to control contaminants that are invisible to the human eye, the manufacturing cell and in many cases the entire room must be controlled. Robots used in this environment must meet stringent clean room certification requirements to prevent them for acting as a source of contamination.

Much of the hardware used in a clean room robot is the same as any other robot with the important exception of a combination of sealed covers to prevent particles from escaping the robot, stainless steel hardware, proper non-gassing lubricants and vacuum to evacuate any internally generated particles. Robots for clean room processes have special considerations for harnesses, . . . “which can be a serious particulate generator and a major design challenge for clean applications,” said Scott Klimczak president of CHAD Industries, a pioneer in the area of wafer and substrate handling WLP I (Wafer Level Packaging) applications.

As a matter of practice, materials prone to particle generation are substituted or coated to eliminate the potential for contamination.

Certification is done by counting the number of particles generated when the robot is in motion. For this process the industry uses particle counters that are calibrated to meet or exceed the standards set by NIST (National Institute of Standards and Technology). In addition to NIST traceable practices, other standards of particle counter calibration include Japanese Industrial Standard (JIS) B 9921, Light Scattering Automatic Particle Counter, and ASTM F 328-98, Standard Practice for Calibration of an Airborne Particle Counter Using Monodisperse Particles. Adept Technology, Inc. a leading manufacturer of clean room robots tests robots both internally and through third party testing and certification to ensure integrators and end-users deploy their equipment appropriately to meet manufacturing cleanliness requirements.

There are two accepted clean room specifications, the ISO 14644-1 spec and the Fed 209E spec.

Depending on the cell design and the robot style selected, a lower class robot may be used and still meet the overall system requirements if the system is designed appropriately. For example, for a semiconductor wafer application, if a robot can operate under the wafer with a vertical laminar flow of clean air present sweeping the particles away from the product, the ultimate requirement for the robot may be less stringent.

Installing the clean room robot requires attention to cleanliness. “Robots built for Class 1 environments are wrapped in several layers to protect them as they are shipped to the site,” said Kevin Lonie, application sales manager for Clear Automation, a Connecticut based automation integrator specializing in the design, engineering, fabrication and installation of integrated robotic and machine vision systems. “Then at the site the equipment is moved through progressively cleaner spaces as the wrapping is wiped down and finally removed before entering its ultimate clean room destination.”

Once wiped down with clean room wipes to remove any foreign particles, it is a good practice to connect the robot to the plant’s vacuum system and evacuate the robot for several hours to make sure all particles are purged completely.

www.adept.com

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View a full photo gallery here

The wearable robotics suit is being designed to help with the many logistics challenges faced by the military both in and out of theater. Repetitive heavy lifting can lead to injuries, orthopedic injuries in particular. The XOS 2 does the lifting for its operator, reducing both strain and exertion. It also does the work faster. One operator in an exoskeleton suit can do the work of two to three soldiers. Deploying exoskeletons would allow military personnel to be reassigned to more strategic tasks. The suit is built from a combination of structures, sensors, actuators and controllers, and it is powered by high pressure hydraulics.

Representatives from Paramount Home Entertainment, including the actor Clark Gregg (aka Agent Phil Coulson of the Marvel® Movie franchise) were in attendance to capture footage of XOS 2 to include in a video that’s being produced to support the release of Iron Man® 2 on DVD and Blu ray.

www.raytheon.com

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Smart engineers copy ideas. Great engineers copy nature. Festo’s Bionic Handling Assistant is a robot arm modeled on an elephant’s trunk (or Dr. Octavius if you’re a Spiderman fan), and it has all the supple flexibility of the original. Using hollow plastic chambers that change size with air pressure, the Bionic Handling Assistant can move through an incredible range of motion in three dimensions. It’s designed to provide gentle forces, and to give when pushed, making it safe for working with humans in a working environment.

The Bionic Handling Assistant was developed through Festo’s Bionic Learning Network, a coordinated group of industrial and academic research partners interested in bringing nature inspired concepts to robotics.  However, all this biology inspired innovation is really only going to be useful if we can find the right applications. Opportunities for the Bionic Handling Assistant in medicine, manufacturing, and mechanical repair are shown below.

For a better idea of how the pressurized air allows the Bionic Handling Assistant to move, here’s a more detailed animation of the robot arm:

No matter where it eventually is applied, the Bionic Handling Assistant is a good sign that engineers have a lot to work with when mimicking natural structures. With all the humanoid robots running shuffling around it’s important to remember that the primate form is only one of many successful architectures we should be copying. Robots that swim like fish, fly like insects, and form colonies like bees could all have crucial applications in the years ahead as we continue to explore the world. It will be interesting to see which animals the Festo Bionic Learning Network pursues next.

www.festo.com

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The new work space design of the RS4 robot provides a pallet size of 778mm x 778mm. A pallet size this large would normally requre a SCARA arm which is more than double the size. Imagine now being able to use a 550mm arm for applications that used to require a much larger 1,200mm arm.

The EPSON RS4 robot offers these features that differentiate it from other SCARA robots available on the market today:

* Industry Leading Work Envelope Usage
* No Lost Space in Center of Work Envelope
* Superior Cycle Throughput
* Zero Footprint Robot
* 450 Degrees Axis Rotation
* Exceptional Flexibility

EPSON Robots
www.robots.epson.com

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The lab-tested material responds to almost the same pressures as human skin and with the same speed, they reported in the British journal Nature Materials.

Important hurdles remain but the exploit is an advance towards replacing today’s clumsy robots and artificial arms with smarter, touch-sensitive upgrades, they believe.

The “e-skin” made by Javey’s team comprises a matrix of nanowires made of germanium and silicon rolled onto a sticky polyimide film.

The team then laid nano-scale transistors on top, followed by a flexible, pressure-sensitive rubber. The prototype, measuring 49 square centimetres (7.6 square inches), can detect pressure ranging from 0 to 15 kilopascals, comparable to the force used for such daily activities as typing on a keyboard or holding an object.

A different approach was taken by a team led by Zhenan Bao, a Chinese-born associate professor at Stanford University in California who has gained a reputation as one of the top women chemists in the United States.

Their approach was to use a rubber film that changes thickness due to pressure, and employs capacitors, integrated into the material, to measure the difference. It cannot be stretched, though.

The achievements are “important milestones” in artificial intelligence, commented John Boland, a nanoscientist at Trinity College Dublin, Ireland, who hailed in particular the use of low-cost processing components.

In the search to substitute the human senses with electronics, good substitutes now exist for sight and sound, but lag for smell and taste.

Touch, though, is widely acknowledged to be the biggest obstacle.

Even routine daily actions, such as brushing one’s teeth, turning the pages of a newspaper or dressing a small child would easily defeat today’s robots.

Bao added important caveats about the challenges ahead.

One is about improving the new sensors. They respond to constant pressure, whereas in human skin more complex sensations are possible.

This is because the pressure-sensing cells in the skin can send different frequencies of signal — for instance, when we feel something painful or sharp, the frequency increases, alerting us to the threat.

In addition, Bao warned, “connecting the artificial skin with the human nerve system will be a very challenging task”.

“Ultimately, in the very distant future, we would like to make a skin which performs really like human skin and to be able to connect it to nerve cells on the arm and thus restore sensation.

“Initially, the prototype that we envision would be more like a handheld device, or maybe a device that connects to other parts of the body that have skin sensation.

“The device would generate a pulse that would stimulate other parts of the skin, giving the kind of signal ‘my (artificial) hand is touching something’, for instance.”

In the future, artificial skin could be studded with sensors that respond to chemicals, biological agents, temperature, humidity, radioactivity or pollutants.

berkeley.edu



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It is important to see that the graphical representation of motion in “time displacement” plot is also a very literal representation of the mechanical aspect of motion.  The area under the curve is the mechanical work done by the system.

The acceleration leg of the trapezoid is the energy needed to bring the load from rest to a constant speed.  The acceleration profile is expressed simply as a scalar changing velocity that is increasing in value until the desired speed is reached.  The first derivative of velocity is acceleration, or the rate of increase of velocity over the unit change in time.

What might be of interest here is that the acceleration changes from a positive value to zero when the desired speed is reached.  Then acceleration is zero, because the system command will be for a constant speed with no acceleration.  And in PID type controls, the transition from positive acceleration to a zero acceleration invariably causes velocity overshoot.

Since everything can be mapped with respect to time, isn’t it more straightforward to consider the inflection points along the way and change the control methodology according to what is going on in the real world?

So coming up to the transition from accelerating to not accelerating, we know that the first derivative value is decreasing to zero.  Maybe our control strategy should be to switch from the velocity loop control and switch to the torque loop so we can decrease the current going to the motor.  This will soften the transition point and minimize overshoot without the use of PID control.

Torque control during fixed position control also has some intuitive benefits.  Any disturbance in position is countered by an opposing torque, or current control through the servoamplifier, to restore position.  This behavior can be embedded in the amplifier and does not require intervention from the controller, minimizing control system loading.

PID control, while enormously successful over the years, is a sort of averaging solution. We will apply gain values across a wide range of motion conditions in hope that they will work satisfactorily for all states over the time of the move .   But if we consider other possibilities, other strategies for control become possible.

This has been the goal of “adaptive gain” solutions which exist today and have evolved over the years as control technology has become cheaper and more powerful and the industry has acknowledged the weaknesses of PID control. By paying attention to the “inflection points” along the trajectory fo the motion, different control strategies are made possible that are simple, reliable and in some cases, more robust than what is possible with conventional control.

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From the Biorobotics Lab at Carnegie Mellon University, a snake robot (Snakebot) demonstrates how it can climb a tree and look around.

Please keep in mind that this robot climbed a specific tree with a specific trunk width about 1 meter off of the ground. The researchers working to design, build and program these robots still have much work to do to get these bots to climb taller trees of various sizes and to navigate over branches and wires.  This may be especially useful in military tactics and surveillance

www.cmu.edu

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WITTENSTEIN Aerospace & Simulation has been the control loading leader in the flight simulation market for more than a decade. The Company has taken its expertise and applied it to telerobotics, where a user controls an axis or entire vehicle remotely. WITTENSTEIN’s products provide the user with feedback of the remote axis through electrical linking and force control technology.

The main features of the sidestick systems for telerobotics are superior efficiency, compact design, and electric linking with force feedback. These result in smooth operator feel, no need for additional mechanical linkages or hydraulics, and a standard off-the-shelf system solution that utilizes standard wall-outlet power. The robust nature of the WITTENSTEIN systems allow for up to 10 axes per control module.

Sample areas of application for this technology include remote product testing for reasons due to environmental or equipment restrictions.

www.wittenstein-us.com

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One aspect of artificial intelligence gave rise to expert systems.  Complex systems like diesel locomotives are very difficult to repair because of the large number of parts operating together.  Human experience accumulated after years of working with diesel locomotives needed to be captured in order to prevent each generation from having to apprentice workers over long periods of time in order to learn how to troubleshoot these systems. So programmers in the early days of AI were employed to learn and program the diagnostic procedures developed by skilled workmen over many years.

These programs were very successful.  But in no way do they replace human intelligence and insight.  This is simply an example of subtlety in programming a specific area of human experience.  Speech recognition continues to be a challenge after decades of effort, limited to transcription applications and simple material handling instructions.

Another area that came up was large scale logistical mapping, another Expert System.  What is the most economical way to use airplanes to transport people around the US?  When you think of a large air carrier and the number of airplanes, flights, destinations and how they might be mapped together to get the best use out of the airplanes, it is a problem that is too large and complex for a single human to work with.  Enter the expert system programmer.

But in none of these cases can a computer program exceed the boundaries of it’s programming.  Can the autonomous Jeep get from it’s starting point to it’s destination?  Yes.  With many man-years of programming and a vast array of computing power, proper deployment of sensors and actuators, and a lot of stored energy.

Can the autonomous Jeep perform any other task?  No.  Regardless of the sophistication, the machine cannot exceed the boundaries of it’s programming.

Can we teach machines to learn?  So far, only in the most crude and rudimentary way.  But the course of the learning is again bounded by the programming.

And again, I will defer discussion of true intelligence or consciousness.

But what robotics can do to expand it’s usefulness is to mimic simple human tasking where it is cost effective and where the robot can “outproduce” or exceed the precision of a human.  Robotic welding, for example, has reached the point where a basic robot welding cell is less than $50,000.  So the cost of entry, the learning curve and complexity of implementing a welding robot cell in a small production facility is very reasonable.

Will robots be used in “human service” applications?  Sure.  ”Robot, vacuum my living room”  No sweat.  We can already do that with a Roomba only it doesn’t have voice recognition yet.  We have robots that can mow the grass in the front yard and avoid shrubs and trees.  Very cool.

Will we have robot servants like C3PO in Star Wars?  Hopefully more intelligent, C3PO was kind of dumb.  Simple tasks like serving a drink at a bar? Yes, that’s been done too, although it doesn’t have philosophical conversations with customers.

Will robots be able to provide basic care in hospitals and for the elderly?  Anything is possible. It will come down to how far we can push the envelope of programming, safety and return on cost.  Certainly we get robots to get a cold beer from the fridge.  But if the fridge is empty can it run out to the store and get us a six pack?

Not anytime soon.

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The US Department of Defense (DoD) has been seeking a way to reduce the cost of producing cast spare parts. The Advanced Technology Institute (ATI) currently leads several national collaborations that are developing advanced robotics capabilities and implementing both new and existing robotics technologies in response to the DoD’s need.

One collaboration is with the American Metalcasting Consortium (AMC). The ATI-managed AMC partner companies, like Clinkenbeard, are using robotics technologies to support legacy weapon systems; which could help meet the Defense Logistic Agency’s goal of dramatically shorter lead times for the production of legacy weapon systems parts. The patented Clinkenbeard® Toolingless Process proved that it could reduce lead times for military cast spare parts from six to twelve months to six to twelve days.

The results, according to ATI, also demonstrated that the Toolingless Process can reduce capital investment by as much as 35%, reduce individual parts cost by up to 20%, and improve cycle time by 25%.

Lead times often exceed a year because technical data may require reworking, including the development of a solid model of the part. But, even when a solid model is generated first, the Clinkenbeard process can supply a cast part in less than a month. The secret is computer-generated molds with no tooling.

The Toolingless Process consists of machining sand cores and molds, and is accurate. According to the company, this process can reduce the lead-time to obtain development castings by up to 90%. With this process, you can:

• eliminate the need for prototype tooling, depending on project requirements.
• make and test multiple design iterations during product development, from the simple to complex parts.
• reduce the cost of production tooling for one-of and small quantities.
• obtain accurate, prototype parts while large quantity tooling is made.
• eliminate tooling inventory.
• match exact production core materials and chemical levels so that prototype castings emulate production.
• incorporate engineering changes into high-volume production sand cores.

Clinkenbeard developed the sand machining process using CNC machining centers. By using robots with sand machining, company technicians can use the process on much larger molds and cores. Robotic technology will reduce the cost dramatically compared to the same expenditure for CNC machining centers.

Clinkenbeard
www.clinkenbeard.com

American Metal Consortium

http://amc.aticorp.org/

Defense Logistic Agency
www.dla.mil

Advanced Technology Institute (ATI)
www.aticorp.org

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