Engineering Education

I was involved in advanced brushless motor development for a couple of years.  It was an interesting period of time.  We did a lot of cool work on advanced thermal packaging, winding encapsulation, advanced robotic actuators, ultra light weight starter/alternator, hybrid minivans.  Pretty cool stuff.

One afternoon we were working on the question of bond strength of epoxy.  the problem was how to bond neodymium iron boron magnets to a steel rotor.  As the RPM increases, the centrifugal forces is increasing exponentially to tear the magnet off the rotor.  This is especially annoying when you are trying to engineer a high RPM rotor.

We were meeting in the “pit” where a shack had been erected to provide a safe enviornment to exercise various rotor designs in the hope of creating a reliable design.  A group of us were discussing the pro’s and con’s of a particular design.  What was shocking was that it was apparent from the conversation that non of the younger guys on the team, recent college grads, knew how to construct a single variable experiment.

So I started asking the guys, ‘have any of you taken logic and scientific method?”  Blank stares.  ‘Uh, no’  Anybody heard of Mills Methods?  ‘Nope”   Further conversation revealed that the course Logic and Scientific Method, was no longer required for graduation in engineering.

Well, we got through the afternoon and successfully tested the rotor. And we got to a working design without major incident. But it was touch and go for a while.

I mention all this because the recent commentary from some readers reminded me of the importance of the subject.  On the one hand, Logic and Scientific method may not sound like a big deal.  But critical thinking is necessary in the engineering field.  And in life as well.

If we don’t understand the information and context of the deluge of input that we are surrounded by, we will surely be the victims of it.  The proper role of education is to equip students with tools so they learn HOW to think.  Instead we are surrounded by information that tells us WHAT to think. There is a big difference.  And we need to understand that difference.

Whether it’s Global Warming, Energy Policy, whatever.  I approach these subjects with some skepticism because the dominant media conversation is purposely obscured.  For example, the Wind Energy advocates never talk about how much their stuff costs and what the typical payback period is.  It simply doesn’t make sense that the dialogue is so obscured, and when people make their arguments obscure, as our politicians tend to do, it’s time to be suspicious and look for answers.

As regards simple metrics like return on investment, my background is industrial.  Historically, we look for 1-2 year payback.  If it’s not in that time frame, it’s not likely to happen.  And we need to apply that hurdle to the alternative energy arena.  Government may have a role to play, but we also need an aducated and informed electorate that understands the difference between fact and fiction, and people that are engaged in the decision making process.

Rixan Introduces Fully Ease-Of-Use Swivel Stand System

Dayton, OH — Rixan Associates, Inc. recently introduced unique Swivel Stand Systems (the RSS-1000 and RSS-2000) that offer repeatable positioning for automated operations.

In many automated machining operations, the operators require access to the machine to set-up the job and perform routine maintenance. The robot, or automated feeder, must be removed and later reinstalled to provide the access.

The Rixan swivel stand allows the robot to swivel out of the way for access, and later, be easily repositioned with excellent repeatability.

According to Stephen Harris, President of Rixan Associates, the Rixan Swivel Stand is very rigid with repeatable support of a robot or other machinery up to 250 kg (550 lbs). The mounting pattern can be set to client specifications with various heights and arm lengths available.

www.rixan.com

Flashback

The electric car might just be the most difficult mechatronic challenge ever.

I moved to Denver Colorado in 1990 to become part of the electric car industry.  I worked really hard because I believed then, as I do now, that the electric car was something we all needed.  And we still do.  I didn’t care (and don’t care now) if it’s a hybrid or pure electric, although a pure electric is a much more difficult technical challenge.

The company I worked for was doing advanced motor and drive development specifically for the electric vehicle.  Their perspective was that you could solve the mechatronic problem with high efficiency brushless dc motor technology.  That also meant you had to create a special power electronics solution for that motor.  It got kind of messy.  A motor winding for which there was no known manufacturing process.  Custom 45KW analog power electronics with water cooling.  Cutting edge stuff.

We produced some major milestones.  One was a Chrysler Town and Country mini-van hybrid electric.  I was asked to show the car at the first Denver Grand Prix.  I got to drive the car home each day from the Grand Prix.  The car was very heavy and didn’t have a lot of acceleration, so making the climb from downtown Denver at 5250 feet of altitude to my home in Lakewood at 6200 feet of altitude was a bit of a strain on the car.

The car was not heavily marked but it did say hybrid on it.  I got mixed reactions from people passing me on the freeway.  Some gave me the finger for slowing traffic, some leaned out of their cars and applauded that we had something that worked.

So imagine my surprise when I found the new Chrysler Hybrid SUV specs on their website with virtually the same specs as the vehicle I drove home every day from the Denver Grand Prix.  WOW!  What a flashback.  It’’s like Deja Vu all over again!

I am having a problem with what to think about it.  Yes, the engineering is better than what we were able to get done in 1990.  We didn’t have lithium batteries or millions of dollars to work with.

A lot of people shelled out their hard earned cash to fund a little startup that would be the only company in the US with a Hybrid vehicle that was qualified for the Los Angeles Clean Air Initiative.  LA issued a contract for 10,000 vehicles that no one ever got to build.  No one in Detroit would work with us to provide rolling platforms.  The DOE ignored us and paid hundreds of millions to Ford who delivered practically nothing in the 1990’s.

So what took so long?  You tell me.  Was it 2 years of $4. a gallon gasoline that changed people’s mind about the importance of the electric car?  Was it the exodus of new car sales that currently has Detroit in a funk?  Was it the threat Middle Eastern terrorism after 9/11 ?

I don’t know.  Maybe things just take time.  17 years?   Maybe being an innovator is a difficult path to tread.  Platitudes.

Innovation is a gift that we need to encourage.  It’s still the best answer in tough times.

Applying Motors

Motion control and mechatronics continue to embody the extreme opposites of engineering, phenomena that are incredibly simple and incredibly complex at the same time.  This apparent contradiction is experienced in many areas.   The operation of a fan is one of the most common and basic motor applications, yet to understand the starting torque and acceleration requirements, you have to do some exponential equations because the force of air pressure acting on the fan varies with with cube of the speed.  The relationship between motor speed and the number of cubic feet of air moved is only the first tradeoff constraint.  The amount of time allowed for the acceleration of the fan is a second order constraint which is coupled to the amount of power needed by the motor over time.  The current utilization of the motor combined with the voltage and frequency will define the efficiency of the overall system.  Assuming there are no belts and pulleys to transfer mechanical power to the fan load, which, of course, there usually are, we are dealing in units of volts, hertz, amperes, revolutions, cubic feet of air, torque and time. If you are keeping track that’s 7, count ‘em, a 7 variable system to turn a fan. 8 if you consider efficiency, but efficiency can be derived from the others. So much for simplicity.

What I find really interesting about this situation is that the motor industry and machinery builders continue to apply electric motors using simple time (speed) and torque tradeoff analysis.  Heck, that’s only 2 (or 3) variables depending on how you look at time.  Yes, it has some sophistication.  Motor sizing programs take into account acceleration and thermal limits.  And it should be said that all systems of energy conversion must ultimately be considered as thermodynamic systems.  That is, how much energy can I convert, and how quickly, before the waste heat becomes an uneconomical burden to the process.   But it’s a bit of an oversimplification to apply a motor to a load using only two variable.

To make matters worse, all motors that are for sale are solutions that are based on manufacturing and cost constraints.  They are an average of many designs and requirements blended into an off-the-shelf package that is readily available.  The motor’s design has very little to do with the particular requirement that you and I might be faced with in a given application.  The information exchange between the motor vendor and the engineer applying the motor is to understand the peak and continuous torque that the motor can produce and fitting the curve to the load requirement.  Making this a predominantly mechanical exercise, motor output (mechanical) to load requirement (also mechanical).

But in the age of the Personal Computer, with ever more powerful design tools available, it appears to me that the next frontier will be applying the new tools to the old motor and load problem.  I know some of the people working on it, and the progress is very good.  A new and very powerful age of design tools is dawning.

Compliance Problems

The field of mechatronics has many interesting tangents.  One of the most subtle, yet important aspects is the field of materials properties.  The materials selected for use in actuators and machinery becomes a significant determinant in what the inertia load will be and even more importantly, how it will behave.

There are many properties of merit to the designer, and stiffness is one that should never be overlooked.  Stiffness can be a valuable tool to use in making mechanisms that have high repeatability and  operate at high speed.  Sometimes the only way to solve throughput problems is to substitute titanium for steel.  Titanium is much higher strength than steel and lower density so it has high great value in reducing inertia and retaining stiff response.  But titanium is very expensive and difficult to machine.  So this solution isn’t always econonical.

Interestingly, Aluminum is a very popular substitute for steel because it is one third the density of steel and machines very easily.  This can result in parts that are actually lower cost and reduces the power required to operate the mechanism.  But as speeds or acceleration requirements increase, the relatively soft aluminum can flex and lose critical position.  This is one case of compliance.  And if you have to do high speed registration, compliance can be a real problem.

But compliance is something we need to avoid shock load and premature mechanical failure in moving parts.  Sprocket and chain drives can have compliance.  Belt driven actuators have compliance.  Motor couplings have compliance.  And properly applied, compliance has great value.

But there are a lot of cases where compliance is present but not accounted for.  Many roller transmissions claim to be zero backlash, but the very nature of the technology has some compliance in order to make it work. So as the load is starting and stopping there is some “flexing” or torsion that must be accounted for.  In essence, there’s no free lunch.  If there’s no backlash, there must be some other aspect of the design to account for.

So when is compliance a problem? Fortunately, not very often.  Most systems that have compliance in them, it’s intentional.  But there is a lot of technology where it’s not apparent.

In order to diagnose compliance problems, extra position feedback sensors on the load are needed.  Particular attention needs to be paid to how precise it needs to be to measure the position error.  The other key factor will be the minimum time needed to measure the position error. As system throughput increases the time available to measure the error decreases.

By measuring the error created by compliance, it can be controlled.  Compliance can be an ally in making machinery that has more controlled starting and stopping of loads, which translates into quiet operation and longer operating life.  Overall, a pretty good deal.

Zuken Implements Mechatronics Design Strategy and Launches New 3D Modeling Solution

Munich, Germany and Westford, MA, USA – Zuken has made another step to strengthen the link between the electronics and mechanical design worlds by enabling parallel MCAD/ECAD design with a new collaborative software tool called Board Modeler. This forms part of company-wide strategy underway to deliver increased versatility and reliability between the mechanical, electrical, and electronics design disciplines. Board Modeler docks in Zuken’s electronic systems and PCB design suite CR-5000, allowing layout and mechanical engineers to work more closely together in synchronization from as early in the process as floor planning. In this way Board Modeler gives engineers the power to rise to the challenge of integrating PCBs into ever more mechanically complex products, while saving time through parallel working and the elimination of design re-work.

Layout Engineer Gets True 3D
For the first time, with Board Modeler the layout engineer can easily work in a 3D environment modeller. The true component shape is now visible, rather than just showing items approximated as a cuboid or cylinder (2.5D). This is achieved by performing 3D conversions of footprint data, importing parts made by MCAD, or by using Zuken’s online component database, which contains over 4.5 million accurately detailed 3D components. This enables the engineer to carry out floor planning, perform collision checks between the PCB housing, components or other PCBs; all working with the true 3D component shapes. Board Modeler also eliminates duplication of effort between electronic and mechanical design by permitting the layout engineer to import board outlines, pre-placed parts and obstacles directly from mechanical CAD tools. It also automatically back-annotates any board and placement changes, as board outline and restriction areas, into the PCB design, whether new or imported, so any required layout action, like re-routing, can be done easily. Industry standard neutral file formats, including STEP, ACIS , STL and IDF, are used to bridge the gap to virtually any mechanical CAD system.

This solution is the logical step forward from Zuken’s previous tools – EM Designer and EM Checker, and improves 3D capabilities through direct integration with board design solution CR-5000 Board Designer and manufacturing board panelling solution Board Producer, allowing users to handle more complex 3D data. This smooth integration also means board layout structures, with all the material properties and electrical constraints, can be exported via Board Modeler into numerical simulation tools for mechanical, electrical or thermal verification. Simulation results can then be easily back annotated into CR-5000 tools for design modifications.

Board Modeler also features a multi-board option that allows design verification of multiple boards and chassis on a multi-site global basis.

www.zuken.com

The Innovation Equation

When people start talking about how “technology will restore our economy” I tend to get a little nervous.  Generally, it is not good to mix politics and science.  It is worse for politicians to make national policy using science or technology as the justification.  Politicians are rarely technically astute enough to interpret the opinions of the “experts”, especially when they conflict with each other.  And due to the politics of funding, experts sometimes have to be politically sensitive to their patrons.

What is the proper role of government in the realm of science and technology?  Personally, I think there should be no direct role.  But the cat’s out of the bag.  And government has taken a large part of the role controlling what technology we as a nation will work on when $9Bil is spent by the DOE and many times that is spent through the various military and non-military agencies of the government who contract research and development.  There is a legitimate interest in our country’s defence, but the lines have become blurred as more and more funding comes from government sources.

Industry in the United States, it seems, has outsourced a lot of the Research and Development that it used to fund.  The Euorpeans work closely with their Universities to leverage the available talent at low cost to get some things done.  The US is doing some of that, but maybe we need to do more.

Sometimes there are bigger forces at work that no single company can overcome in its marketplace.  Transitioning from gasoline based cars to electric cars might be one.  Auto makers need volumes of 50,000 to 100,000 units to get cost effective.  Notwithstanding that claim, I am pretty sure that the Japanese hybrids are just now reaching those volumes.  Those are cars American workers didn’t get to build.

And taxing things is a form of economic punishment.  Taxation is intended to discourage certain behaviors.  But taxing (punishing) is a form of negative reinforcement.  Instead, wouldn’t we be better off by encouraging good behavior?

So here’s are a really radical idea; instead of taxing carbon, or creating a shadow currency that only a few large companies can profit from, why don’t we incentivize any new technology that can be substituted for combustion?  Let’s figure out some novel ways to run our systems without burning something.  Carcinogenic diesel emissions and other atmospheric polutants, will gradually disappear.  Clean air and water will be an almost certain result in years to come.

Solar Power, Wind Power and Electric Cars all avoid combustion.  Tax Credit? You bet.  Fuel Cell Bus(already available) for city transportation systems? Yup.  Injection heaters for hot water?  Hot water heat exchanger for central heating systems? That would replace burning natural gas, right? Cha-ching, tax credit. Electricity generated by atomic energy in mini-reactors instead of burning coal? That too.  In fact, we could affort to give the whole coal industry help to convert itself into the fuel refining and encapsulating industry instead of paying $60 to $90 Billion to rebuild the national grid.  The grid won’t be needed except in an emergency.

We would have so many new businesses opening up, employment would go up and the national debt would go down, without raising taxes.  Let’s give American innovation a chance.

EPSON RS3 Robot

Carson, CA –– EPSON Robots introduces the new EPSON RS3 Robot, featuring all the benefits of a typical SCARA plus more. The unique new design of the EPSON RS3 clearly puts it ahead of other robots in its class with superior cycle times and larger work envelope access thus opening up new application possibilities.

“Unique to the EPSON RS3 is our new work space design which maximizes work envelope usage” stated Michael Ferrara, Director of EPSON Robots. “No other robot vendor offers a 350mm SCARA arm featuring the largest working quadrangle greater than that of a typical 750mm SCARA arm. Since there is no dead space in the center of the work envelope, the EPSON RS3’s largest working quadrangle is 494mm2, which up till now has only been possible with a much larger SCARA robot. With the ability to maneuver back under itself for the shortest movements possible instead of having to move around itself, the EPSON RS3 delivers superior cycle rates. This means more parts processed in less time, while using a fraction of floor space which results in more profits for our customers.”

The EPSON RS3 is a zero footprint robot, thus saving valuable floor space. It is also capable of easy integration into compact assembly cells. Furthermore, the unique work envelope allows for unprecedented design flexibility with over 360 degrees of axis rotation for omni directional access.

The EPSON RS3 is perfect for lab automation and other process heavy applications where large quantities of parts are presented to process or testing stations.

Our low cost, high performance Micro PowerDrive RC180 Controller comes standard with the EPSON RS3 robot which provides the ultimate experience in ease of use, compact size, and reliability. In addition to all of these great features, the RC180 controller also provides our industry leading EPSON RC+ Controls software and lots of fully integrated options such as: Vision Guidance, .Net support, Profibus, DeviceNet, EtherNet/IP and much more.

www.robots.epson.com