Among the mainstays of an industrial economy is construction, housing and commercial in particular.  While these industries are incredibly competitive, there is always room for innovation.  Precisely because it is a mature, competitive industry, really ground breaking solutions are sometime hard to find.

Transcon Steel is a small startup company in Georgetown Texas that makes structural steel building systems.  The innovation comes from the fact that Transcon roll forms flat sheet metal into structural shapes that are highly optimized to reduce weight and increase strength.  The steel structural shapes are formed into large panels with compressed foam which results in structures that are super light weight and extremely high strength.

The new structural panels permit construction of buildings in a variety of applications.  So called “temporary housing” for oilfield crews in remote area can be built in hours instead of days.  Heating and cooling costs are a fraction of conventional structures.  All of which leads to increased opportunities to serve unique construction applications with better solutions.

Transcon’s big challenge will be to create the manufacturing resources needed to produce the structural panels in very large numbers.  The enabling technology of the manufacturing processes?  Mechatronics. The roll forming of sheet metal is a classic application requiring high performance drives to de-reel the strip steel rolls and servo actuators to follow the roll throughout the various forming process that take place to make the final product.

The compressed foam requires unique tooling to form large rectangular panels that can be filled with foam, compressed with hydraulic actuators and cured with heat and pressure to form the final super dense structures.  Amazingly, the cores are made from material that is similar to the conventional styrofoam cups we use for coffee, yet, when the basic material is processed correctly, it becomes strong enough to withstand blows from a sledgehammer.  When it is bonded to an already strong steel frame, you have a complete building system that has incredible structural strength and insulation value.

Transon is negotiating enough new business that it will need a new facility 4 times the size of it’s present location and will hire CAD designers and plant personnel to support it’s manufacturing needs.  If they are successful at marketing the technology in other countries, it will be more of the same.  Lots of it.

And that is how job creation is done.  Someone with an idea, willing to work hard, taking risks, finding people to come alongside and help, to deliver a solution.  Making lives better by employing people, and by delivering a product that provides shelter at a lower cost than the traditional products in the building market.

American Entrepreneurship.

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A lot of it is precisely ‘doing more with less’.  How do we make the same quality of parts at prices low enough to compete with foreign competition?  It’s not easy when the typical pay scale for manufacturing labor is $8 a day in some parts of the world.

There are a couple of obvious components to price competition that don’t get a lot of attention.  Scrap rates and delivered cost.  When a US company buys parts from offshore, any defective parts are very costly.  The direct shipping cost, duties and processing fees are additional and can be 10-15%.

During my years at Rockwell Automation, we investigated the cost of selling US products in different parts of the world.  Depending on where in the world we are talking about, the shipping and logistics can accumulate between 25 and 40% additional cost to the product being sold.

So the cost of scraps and logistics are the minimum cost hurdles for companies seeking to export their products to the US.  Low cost producers have to make parts cheaply enough that the landed cost and scrap rates cost out less than the price of producing them in the US.

Doing more manufacturing in the US requires finding creative ways to lower costs.  That is the second area that is undergoing change.  American manufacturing technology is finding ways to reduce machinery and process costs.  And this area of effort may provide key strategies that will help the US gain back ground in the pursuit of more world class manufacturing.

Innovation processes like additive manufacturing allow fabrication of metal parts with no machining.  For higher levels of precision there are new machine tools that can do final machining to less than 0.001″ accuracy and the costs of machine tools are lower than ever.  These are the keys to producing high quality parts at lower costs.

There are unique mechatronic solutions that can improve machinery performance across a wide range of applications.  The Acme screw which is very inexpensive, has limited accuracy but plenty of torque handling capability.  What happens if you can add a very inexpensive linear feedback technology to the simple low cost Acme screw?  You get a really high resolution linear motion system that is very inexpensive.

The great news is that these products are currently available.  And that means that making better machines that make better parts at lower cost is practical, achievable and there are no technical challenges.  Common off the shelf parts will get it done.

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Some people define servo’s as closed loop versus drives which are open loop.  The term servo does require that there is a feedback device to provide the loop closure.  But there are many AC drive vendors making closed loop inverters to enhance the performance of the motor.  AC drives with feedback are generally used where positioning is required.  So the feedback element is not the determining factor for defining if an application is AC or DC.

The overall power level may define one versus the other, but not always.  Brushless servo motors are generally limited to 7″ or 8″ diameter and an equivalent horsepower rating of 20-30 horsepower.  There are frameless motors with even higher horsepower ratings.  But  the size and power rating are strictly a function of manufacturing and marketing constraints.  For a major manufacturer, the question is really, how many motors of a given size are we going to sell?  Based on the high cost of Neodymium permanent magnets, a larger servomotor is going to be very expensive.

But overall power ratings are not limited when you consider products from specialty companies like Powertec.  Powertec takes standard AC motor frame designs and increases the power density by adding embedded permanent magnets on the rotor.  Since the magnets are Ferrite, which aren’t as expensive, they are much more economical and allow designs as big as 400HP.  So power level by itself doesn’t determine what technology to use.

The real answer is in the load conditions.  What is the dynamic response required for the target application?  The rate of change of the load is the key.  Most AC drives are specified in terms of the frequency response or dynamic response of the power electronics.  This important parameter is expressed in Hertz.

Dynamic response is the ability of the drive to regulate speed when the load varies.  The load torque can change significantly, usually 90-100%, and the drive will recover the set speed within the time defined by the dynamic response.  Typically, an open loop AC drive has a 10 hertz dynamic response, which means that it will regulate to 1/10th of a second.

AC drive technology has improved to the point where dynamic response can reach 200 Hertz when a rotary encoder is added to the motor.  This means the drive can regulate load variations wiithin 5 milliseconds.  Which is pretty fast when the load mass is high enough to require a motor of 25 horsepower or larger.

The basic physics are simply that the bigger the load, the slower the dynamic response.  You just can’t make a ton of rotating mass change speed really quickly.  And that’s how the controls should respond.

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The electric light, for example, which was coveted 100 years ago as the great solution to night time darkness, making obsolete the candle or gas lamp.  Mass production has made the light bulb an inexpensive  commodity on the verge of extinction at about 25 cents per bulb.  The desire to reduce energy consumption is ushering in the age of the light emitting diode (LED) as the replacement technology for electric light.  Every effort is under way to reduce LED costs by any means possible so that illumination will be available that is even cheaper than incandescent lighting when the energy cost over ten years is factored into the new technology.

Even generating and delivering electricity is the result of applying the principles of mass production.  Large generating facilities are able to generate power cost effectively through economy of scale, selling the power profitably at 4.5 cents per kilowatt hour.  Wire, cable, switching systems and other infrastructure are generally costed in at an additional 2 cents per kilowatt hour to deliver the power to your door.  This is an incredible deal, trillion of dollars of resources at your disposal for pennies.

But mass production is not the answer for every aspect of modern society.  Lowering the cost of mass-produced goods implies that there is a requirement for the sufficient numbers of a product to warrant the investment in the necessary processes and tooling to accomplish the task.

Enter 3D printing technology.  Also known as “Maker bots”, this new class of tools is making fabrication a  new American pastime at incredibly low cost.  Where 3D printing equipment has recently been the domain of well-funded large corporations , selling at $10,000 to $20,000 each, 3D printer kits are available at less than $1000.  And lest you think that these are only toys for boys, the additive manufacturing paradigm has taken hold in the metals industry producing high quality parts in various steel alloys and even in titanium.

Why does it matter?  Because anything that lowers the barrier to market entry for new products creates the opportunity for people to enter a market that was previously inaccessible.  The hidden relationship is financial, it is the cost of amortizing the manufacturing resources across a given number of products that makes startup of a new product impractical.  So barriers to entry in new product development are primarily the result of amortization costs.

What happens when a new technology introduces a significant reduction in the amortization cost?  You get the opportunity to experiment with things because the cost of iterating the design is low.  New products can be test marketed and improvements made because there is no major investment in tooling that would have to be modified in order to change the design.  You don’t have to get it right the first time.

And that means that anything is possible.

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The traditional metal cutting machine tool has been around since the 1800′s and was entirely manually operated.  Since the machines were manually operated, the dexterity of the operator became a major factor in accuracy and repeatability of part manufacturing.  Because of the skill required, we still have the term “master machinist” in circulation, even though most machining today is automated.

During the Second World War, the Air Force was confronting the difficulty of manufacturing airplane parts.  Through the work of John Parsons and MIT, the first “punch card” controlled machine tool was built.  Parsons’ company was using early punch card computers to generate a larger number of points along the curve of a wing brace.  The numerical information was then used directly by machinists as a look up table for manually positioning a milling tool.  Parsons realized that if they could motorized the manual process, it could greatly increase the speed of the machining process, lowering costs dramatically and increasing accuracy at the same time.

Gordon Brown’s Servomechanisms group at MIT has recently been working on early forms of closed loop dc motor control for the gun turret on B-29 bombers.  By combining these recent technologies to numerical punch card calculation approach the first Computer Numerical Controlled Machine Tool was demonstrated.

The rest, as they say, is history.  The lessons learned in computer numerical control have been instrumental in every major field of manufacturing.  Cars, electronics, robotics, would not be feasible or cost effective without the underlying control technology of CNC.

Which brings me to a 2 major points as we contemplate the next generation of manufacturing.

Additive manufacturing is maturing rapidly with a wide range of materials, steels and titanium are now available, and precision is improving at the same time.   The surface finish requirements for a large number of parts cannot be achieved with a strictly additive process.  The new wave of additive manufacturing requires a complementary subtractive technology at complementary prices.

Secondly, while there are an increasing number of machine tools at low cost, they are not CNC.  This will likely be the next “breakout” technology.  There are a number of technical hurdles that have to be addressed in terms of reducing the cost to a level comparable with the Makerbot.  With the current generation of dedicated motion controller chips, lower cost step motors and low cost feedback technology, this should be a slam dunk.

Get your pencils out and get after it!  There’s some serious money to be made here.

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Alternative energy in the US has failed to produce the return on investment or to create new jobs in any significant numbers.  Car sales have picked up significantly over 2011, but not nearly at the rate of 16 million cars/year as in the heyday of that industry.  The real estate bubble has burst after a decade of speculation and bad lending practices that continue to depress new construction.

The second industrial revolution, Henry Ford’s industrial revolution, was about mass production and cost reduction.  For almost 100 years we have been perfecting the centralized manufacture of almost everything around us.  Economies of scale that enable volume manufacturing of consumer electronics at lower cost year after year are the result of the Ford approach to manufacturing.

So where do we go from here?  We start re-inventing the industrial revolution.

The new wave of manufacturing has begun with the advent of the Maker Bot and a family of low-cost fabrication tools that can manufacture based on 3D printing techniques.  While solid model prototyping has been around for some time, the magic ingredient is a new family of machines that cost less than $2000. and some recent new entries around the $1000 mark.  At these price points, it doesn’t take a lot of volume to justify the purchase of one of these machines.

There are advanced processes that are becoming available to generate sintered metal parts, even titanium parts, using processes resembling the additive manufacturing process.

Amortization cost is the secret.  Lowering amortization costs and minimum order quantity at the same time results in a fantastic breakthrough in productivity.  It also lowers the barrier to entry into new markets.  So if you have an idea for something that’s never been done before, the cost for development may be a lot lower than you think.  And thousands of people have begun to jump into the mainstream economy because of the availability of these new tools.

While the “maker” tools are limited to plastics, there is progress in the metals arena as well.  The computer numerically controlled (CNC) machine tools have traditionally been the domain of 6 figure costs, HAAS has been making $50,000 machines and last year Tormach entered the market with the “Personal CNC”, a high quality machine that is priced at $10,000.

My prediction?  There is going to be a lot of activity at the $10,000 and below price point to come up with low cost machine tools as a complement to the “maker” bot 3D printer technology.  Additive manufacturing will require a complementary subtractive manufacturing infrastructure at a comparable price point.

And creative American engineers and tinkerers will be leading the way.

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In the wind energy arena the biggest change has been the shift to direct drive permanent magnet generators.  By eliminating the gear “increaser” to convert the low RPM of the propeller system to a high RPM for a standard high power generator.  This is crucial step in bringing the cost of wind power down. Current systems are weighing in at 100 tons and have to be suspended above water or land 165 feet in order to pick up sufficient wind currents to be economically practical.

There is no single solution that is ideal for wind applications.  One supplier has a generator that is made up of 4 smaller units on a single large ring gear.  This system seems to have significant advantages in reducing the size and weight of the generator and makes maintenance more simple in the event of a failure.

Among the major mechatronic challenges driving change in the motor industry, electric vehicle applications are continually pushing the boundary for energy density and efficiency.  The performance demands of electric vehicles and other mobility applications make every percentage point of efficiency crucial to the range of the target vehicle.  This has led to a rash of new motor and drivetrain designs with a variety performance capabilities.

Each new innovation seeks to organize the basic materials of the electric motor in a new way to improve some aspect of performance.  Electric motors are copper conductors, “soft” magnetic steels and many times, permanent magnets.  The basic costs for copper wire at $5-6 a pound, commodity strip steel is about $.50 per pound but has to be punched in precise shapes, coated with insulation and stacked into larger assemblies, and $16. per pound for permanent magnets.  Complex processes associated with motor manufacturing make motor costs considerable.

In a recent development teams in academia in Australia and the US have developed simple low RPM motor structures based on polymer actuators referred to as “artificial muscle”.  While this development is in its early phases, the simplicity and low cost are significant and very appealing.  A demonstration of the new technology can be seen on YouTube at;  www.youtube.com/watch?v=ZcCPNJR5PCMand it is very much worth the watch.

The only sure thing is that we continue to meet the challenge of new market needs with innovation.

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Considering the possibilities of improved personal transportation, the consequences of a major change in transportation technology are significant and should be carefully considered as we move forward.

The major impact of all the technology being promoted these days is increased efficiency and reduced fuel consumption.  Whether your motivation is reducing emissions and cleaning the air, or you are interested in reducing your cost of transportation, the requirement is the same; get more miles out of a gallon of gasoline or eliminate gasoline usage altogether, as is the case for a pure electric vehicle.

Across the entire population of cars in the US, the average fuel efficiency is around 20 miles per gallon. Despite the demand for higher fuel mileage from consumers, this situation hasn’t improved much in the last few decades.  A dismal thought in contrast to the claims being made these days for the new solutions.

The US consumes 383.25 million gallons of gasoline and diesel fuel per day.  This all goes into transportation.  The only fuel going into electrical generation is in diesel gen-sets for backup and remote power, just in case anyone is thinking about the barrel- of-oil-to-electricity energy equivalency.

Imagining a future in which gasoline usage declines is not difficult.  I drive a Ford Fusion for work which is averaging 30 mpg combined city and highway.    If the US fleet average is 20 mpg, increasing that average to 30 mpg implies decreasing the amount of gasoline sold by 1/3.  Currently, gasoline retails for $3.25/gallon, or $453 Billion annually at the pump.

So a sharp change in usage due to efficiency or an increase in the number of electric vehicles, is cause for concern from oil & gas exploration companies, gasoline refiners, distributors and dealers.  Unless gasoline prices continue to go up.  In which case there would be less gasoline solid at roughly the same total revenue, which suggests that higher profits might be the side effect if the true cost doesn’t go up.

What about tax revenues?  The direct state and federal tax on gasoline is about 40 cents per gallon.  This does not include large excise taxes collected by the states, taxes paid by refiners and distributors, etc.  In fact, it would be hard to calculate how much of gasoline pricing is taxes and how much is the cost of the product.  Regardless, at 40 cents/gallon, the daily revenues are $153 million and the annual is above $55.8 billion.

Given the current economic picture, is there any level of government that is willing to give up the tax revenue from gasoline?  Probably not.  Is this any different than “Dollars for Oil” at the UN a couple of years ago?  Probably not.  But we thought that was a scandal.

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Many of the constraints of the work are environmental.  If work is being done outdoors, then temperature and humidity are a factor.  Felling trees and in the forest requires extremely high forces due to the work needed to cut through a tree and drag it to a truck to be hauled off for processing.  Processing trees, even in a plant environment, requires some serious hardware, 125 horsepower band saws are not unusual.

Doing work on a ship or oil rig has additional constraints because of the presence of explosive fumes and fuels.  Often the need to avoid any possibility of igniting a combustible atmosphere causes engineers to apply pneumatic control systems.  Yes, there is still a compressor somewhere to generate the compressed air supply, but that is usually remote or contained to avoid exposure to the volatile atmosphere.

Environmental constraints come in many forms.  Extremely high temperatures push the limits of what is possible.  Making glass, semiconductors, and primary metal processing are all high temperature environments where engineers have developed whole technologies in order to bring us the materials we use in everyday life.

The simplest action of rolling or sliding becomes a real challenge when environmental constraints are added to the work statement.  Sawdust becomes a potential abrasive in woodworking environments that can introduce severe wear in moving parts.  Corrosive and explosion proof atmospheres as well as food industry applications introduce all sorts of chemical compatibility problems that require special materials and processes in order to meet strict guidelines for safety.

As always, resourceful engineers have worked out solutions for all of these difficult applications.  One family of solutions to rolling applications is the use of all ceramic bearings.  No steel, no lubrication.  None is needed because the ceramics are extremely high purity to start with and have extremely high precision surfaces eliminating the need for lubrication.  No outgassing or contamination to worry about.

Other solutions take the form of air bearings and non-contact material handling devices.  Air bearings have become more readily available for conventional applications, but are particularly compelling in large machinery applications where precision is required.  Large flat screen display glass  presents unique challenges that successfully addressed using a combination of air bearing regions and vacuum regions to move the glass without actual contact and with overall flatness measured in millionths of an inch.

A unique solution in pneumatic material handling takes compressed air driven into a funnel shaped recess and creates a vacuum in the center and an air cushion at the edges where the air is exiting.  This creates a vacuum pickup that never quite comes in contact with the part, leaving no marks.  Perfect for solar cell and some food and beverage applications.

Engineers continue to meet the unique challenges of industry and create commerce at the same time.  And that’s what it should be about.

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Start with the big loads.  Plant air handling, building HVAC and lighting are generally a lot more significant in total Watts or equivalent horsepower.  1 Horsepower is equal to 746 Watts.  If you are located in the northern states, winter heating uses a lot more energy than summer air conditioning.  In the southern states, it’s the opposite.  There is one study that puts the northern thermal cycle at a much higher overall cost, so everybody needs to move their manufacturing to the south.

Check all the integral horsepower motors in the plant.  A recent DOE study shows that over time, many motors get replaced with whatever is readily available in the next larger frame size.  This is in reaction to plant failures where the exact replacement motor is not handy or on the shelf.  The result is that the plant power and power factor can be very poor because there is a lot of excess capacity that is not being used efficiently.

Industrial plants also suffer from peak demand billing practices.  The utility company agrees to provide power, but large users get billed extra when they have peaks above their average usage.  Again, look at the large loads, and see if some or all can be put on soft starters or inverters with longer starting profiles.  AC motors try to get to full running speed and spend several seconds at poor power factor and huge inrush currents during starting.  Most motors require at least 4 seconds to get to speed.  So, is there a savings opportunity if you can get by with a 6 to 10 second starting period?  Yes, there absolutely is.

The smaller loads like individual plant floor machines are a little harder to regulate.  Some production machines consist of dozens of individual motors and sub-systems.  In large conveyor installations, newer control system turns off whole zones of equipment if there is no traffic for that section.  Use the same strategy in production equipment.  If there is nothing coming into the machine, turn off as much stuff as possible.

Again, look for the largest loads.  In CNC machines, the spindle is usually the dominant load.  Turning off a 10kW spindle motor will save lots more money than turning off 400 Watt positioning axes.  However, don’t pass up an opportunity if one exists.  If there are a large number of individual axes of motion that have low duty cycles, it may be cost effective to put brakes on the load and turn the motors off when they are not in use.

Prudent planning can be turned into real cash savings.

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There is a complex interaction between the two that is often not expressed.  The hardware has “firmware” that defines the exact capabilities of the hardware.  The software is a tool for users to create programs that the hardware executes.  These programs are the embodiment of the useful behavior that the process or machine is intended to accomplish.

So is machine control hardware or software?  It’s both.  The hardware is only capable of executing instructions that we built into it by it’s microprocessor and firmware.  Those instructions are merely a library of possible functions.  The user program calls those firmware functions in an organized manner to accomplish some beneficial result.

There are a couple of really significant issues that are often overlooked.  One is experience.  A lot of experience is required to make good product selections.  The application of control systems involves understanding the application requirements and matching those requirements to specific hardware.  Motion systems that do “high speed registration” for example, require very specific hardware to capture the input signal to define where the registration target is, and then to turn off so that input noise is filtered out.  This is a very specific feature, and if you don’t have it, you generally can’t create it.

Complex control requirements like coordinated motion are both hardware and software dependent.  The simplest example is to draw a circle with two linear axes.  In order to know how to deal with this application the control system must have a dedicated motion controller either as a stand-alone element or embedded within the control architecture.  Most high end PLC’s offer a 4-Axis dedicated controller card that do this.

After all the wrangling is done to get the application and hardware properly scoped out, after all the software development work is done, there is still an aspect of control that is missing from this discussion.  It is the external wiring of power, power protection, and safety systems.  These circuits are separate from the control system hardware and software, and yet embody elements of control that are sometimes necessitated by the hardware itself.

Variable frequency drives and some servomotor drives require time to charge their capacitors.  Most drives has interlocks that will prevent operation until the caps are charged.  PLC processors require a time delay to insure that the I/O devices are powered before the processor “wakes up”.  If not, the processor will immediately fault.  The wiring of emergency stop circuits are physically separate and frequently use reverse power logic, they are energized when “off”, to all detection of broken wires.

All of these behaviors are part of the control system but generally not considered in the early phases of system design.  Yet all are required in order to make safe, working systems.

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This is rather ironic considering the billions of dollars that are spent on control systems across all fields. Is control fundamentally any different if it is inside a car, automating lighting and HVAC in a large building, on an automotive manufacturing plant floor, in a biological resesearch laboratory, or in a giant refinery where chemical products are made.  It’s all control.  And the more we try to define it, the more inclusive we make the definition, the more vague and ambiguous the term becomes.

Efforts continue to increase the power of the PLC (programmable logic controller) across many vendors. By increasing processor speed, memory and capability PLC’s are becoming the universal platform of control as a discrete controller, process controller and motion controller.

Simultaneously, motion control specialty companies continue to increase speed, processing power and I/O structures in an effort to expand the dedicated motion controller as a competitive platform to the PLC.  This is a necessary migration to address control applications where an external PLC could be eliminated.

Is there an ideal mix of motion axes and I/O that will help resolve which hardware solution is best?  Not really.  The fact is that the majority of the market is made up of motion control using stand-alone axes that are triggered by logical conditions in the system.  Coordinated axes require the sharing of pulse to pulse position feedback information.  Stand-alone axes do not share data at that low a level in time.  Most PLC controllers are well able to handle stand-alone axes, especially if an intelligent indexer is used.  This off-loads the motion to the servoamplifier and only I/O handshakes are used.

Part of the ambiguity here is that control is the result of hardware and software together.  ’Control’ seeks to generate complex behaviors using digital methods.  The digital methods, processors, depend on programming techniques in order to implement the desired behavior.  So when we talk about Control, we are talking about hardware and software simultaneously.

What matters most to users of automation technology is both logic control and motion control programming exist in a single environment.  It doesn’t matter if the programming environment is a PLC with motion blocks inside it, or a motion controller with logic blocks inside it.  What matters is that all aspects of a control system can be programmed using a single editor.  Controllers from the major electrical companies like Rockwell Automation and others have opted for the logic-centric programming environment with motion blocks in the ladder diagram.

This approach eliminates the complexity of multi-processor solutions, each with their own programming language, that were commonplace a few years ago.  Multiprocessors have their own unique programming environments and a significant amount of programming to create proper interaction between the various platforms.

Missing from this description is the hard wired control that is part of system start up, power management and safety.  More on this in the next installment.

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Considering the rules for servo tuning first, the ideas are basically simple.  Based on the use of 0-10V velocity command, the control system is designed to regulate motor speed.  A Proportional, Integral and Derivative gain value is used to “tune” the command signal sensitivity to allow the control system to regulate the motor and load performance.  This strategy has been created over the years and is used by almost all servomotor and drive suppliers in the motion control industry.

The Proportional term is the most important value in this approach.  The proportional value is generally the amount the 0-10V command signal will be increased in response to a following error.  The more gain, the more velocity will be commanded.  This will allow the control system to correct for changes in load conditions.  The proportional gain is how the system responds to current conditions.

The Derivative term controls how quickly the control system can add or subtract energy from the load.  The derivative can take the form of dI/dt or dV/dt depending on the specific controller.  This term has two important purposes.  As stated, it defines how quickly the system responds to changes in the load condition, and it exactly parallels the breakdown limit of the power transistors used in the motor amplifier.

The integral term provides correction on a cumulative basis.  All previous error information is integrated over time to provide the system with correction to the control command that “damps” reaction to disturbances.

Notice that all the gains are directly tied to time.  The faster the motion, the more P and D gain is needed to provide adequate response in the control.  Many motion applications have low enough dynamics that servo tuning needs to be very low performance compared to the capability of the equipment.

For most applications, and depending on the gear you are using, the best thing to do is start with I & D gains set to zero.  Use the amplifier autotuning for the motor without the load.  Sometimes these are default settings that are already loaded into the controller.  Tune the motor and amplifier until the P gain seems the best for a step input.  Then add the load and run the autotune again.  If possible, use a step response input that is similar to the type of move you will do in your actual application.

Then gradually add D gain until the leading edge of the step response has no overshoot.  If there was little overshoot without P gain, the motion dynamics are probably very slow and that’s OK.  With D gain set for the application, slowly add I gain and see if the trailing edge of the step response is improved.

If the axis is “hunting” after the motion stops, there is probably too much play in the mechanical system. Using a gearbox with a lot of backlash or a timing belt that is a little loose will produce just enough mechanical error that the servomotor will detect.

Tuning, like everything in motion control, is as unique as each individual application.  There are more complex analytical techniques that can be applied to the subject of tuning.  But I hold to the theory that the majority of applications can be dealt with using simple techniques.

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Government is not the answer.  Anytime government gets involved there is a very high risk that money will get spent and nothing will change.  Remember stimulus 1?  We were assured that if this money were spent, unemployment would never go above 8%.  And with unemployment at 9.1%, the administration wants to try stimulus 2.  No thanks.

What are the real unemployment numbers?  No one wants to really talk about that because it would mean having to admit that the real number is much higher.  Quoting from the most recent data provided by the Bureau of Labor Statistics (BLS), there are 14 million people unemployed, officially, with a labor force that has increased to 153.6 million in August.  That’s where the 9.1% comes from.

But the BLS also reports 2.6 million people “marginally attached to the labor force”.  This category refers to people who have been out of work over the last 12 months, ready and available for work, but had not looked for a job over the last 4 weeks.  I’m still not sure I understand this categorization, certainly someone who has been out of work for 12 months should qualify as unemployed.  The quibbling over details here is clearly designed to hide the real numbers.

2.6 million plus 14 million is 16.6 million which is 10.8% unemployment.  The psychologically dreaded 10% unemployment number could be easily avoided if one can find a way to finesse the reporting categories.   How bad is it really?  Some commentators have said the real unemployment numbers are 16% or higher.  Donald Trump said it was 20%+ in his interview with Greta van Sustern last week.  Personally, I am quite sure its something above 10.8%.

Sadly, this is not the first time employment data has been misrepresented.  Remember how the “Green Economy” would generate 30,000 jobs?  The report that was quoted by many in Colorado State and Federal government used a number of statistical machinations to “fluff up” the numbers.  Workers who put insulation in your home were counted as part of the “Green Economy” as were a fraction of the appliance manufacturers workforce, since effort to reduce energy consumption is a part of that industry.

Attempts by government to increase employment have been mediocre.  The way government creates jobs is by adding more government workers.  Which this administration did like crazy in its first year.  This is not how we grow the economy.  Every dollar spent by government is at the expense of someone who works for a living.    It robs the consumer of discretionary dollars that can be spent in the real economy.  When things get bad enough, government spending robs people of their ability to pay for necessities.  This isn’t how it’s supposed to work.

More disturbing is the trend in the number of manufacturing jobs added per month.  The manufacturing sector added 14,000 job per month in the second quarter, compared to 35,000 jobs per month added in the first quarter.  Not a good trend.

There are two big lessons here.  One is that manufacturing is where the jobs are. American jobs and American manufacturing.  Our politicians have been running down the manufacturing sector for the last 20 years.  Second is that government is not the answer.  Americans and American ingenuity are.  So let’s agree to let American’s get about the business of inventing the future and get the roadblocks out of the way.

Mechatronic Tips

Cooking raw sugar and turning it into white sugar, for example, requires incredible amounts of heat and steam.  And generating steam requires a lot of energy.  Steam is very expensive to generate and almost impossible to store.  The cost of steam is so high that plants measure steam loss by the second.

Producing magnesium as a metal is a large scale electrolytic process.  The emphasis is on electrolytic.  The plant I visited measured current in 10′s of thousands of amperes.  There was so much power that the PC screens in the building had to be triple shielded or the magnetic field of the power distribution system would mess with the displays.  Huge annual cost of energy.

Where industry and commerce require significant amounts of energy to operate, these businesses become very sensitive to the cost of energy.  The same is true for individuals.  As the cost of gasoline increases we must individually choose to use less, or since some people don’t have the option to use less, pay more for gasoline and have less income to spend on other things.

Energy policy under the direction of the DOE and Congress has promoted solar power and wind power over coal, natural gas and nuclear energy.  There are two problems with this approach.  First, these technologies are very expensive.  Any time someone promotes technology and won’t talk about cost, you should be suspicious.  And that has been the history of alternative energy.

The second problem is that there is currently no way to store the power that is generated.  So unless you can use the power immediately, you’re in trouble.  A popular solar project is cited that used solar panels to generate peak power during the summer afternoons during periods of increased power demand when high air conditioning loads are required.  This is still a very expensive solution, but where the utility charges 3 or 4 times more for electricity during peak demand periods, this solution makes sense.  But it is a very limited application.

The question is, who decides how much energy will cost in the US?  State governments grant permits to open a utility.  They also decide what the utility companies’ goals will be.  The DOE has created consensus about alternative energy without approval from Congress.

Do the decisions of the government make sense?  That’s where the controversy starts.  If you are trying to run a business, then anything that increases costs is probably bad.  But no one in government appears to be listening.

Many businesses and almost every consumer is impacted by the decisions made by government.  Every extra dollar that is spent on lighting,  heating and cooling, and transportation is a dollar that is no longer discretionary.  So maybe that’s the real question.  Who decides what you and I spend our money on?

To the extent that government Policy causes dollars to be paid as increased energy expense, then the rest of the consumer economy suffers.  Which is part of the current problems that our economy is currently experiencing.

Mechatronic Tips