DesignNews Magazine, January 2012

PETROSKI ON ENGINEERING Normalization of Deviance 14

January 2012 $15.00

HOT FOR 2012 Cars, Robots, Materials 28

NEW TWIST ON FASTENING Engineers Demand Better Adhesives 46

Accelerating Engineering Innovation

.com

Ethernet Converges on Factory Automation

Standard fosters safety, diagnostics as it displaces plethora of fieldbuses 34

RATED #1 Availability of Product

Data Acquisition Modules, Loggers & Recorders 8/16-Channel Thermocouple/Voltage Input USB Data Acquisition Module

OM-DAQ-USB-2401 $495

• 8 Differential or 16 Single-Ended Analog Inputs • 24 Bit Resolution with Up to 1000 Samples/Sec • User Programmable for Type J, K, T, E, R, S, B, N Thermocouple or Voltage Input Visit omega.com/om-daq-usb-2400

Temperature and Humidity Virtual Chart Recorder iTHX-W3 Series Starts at $295

Visit omega.com/ithx-w3

Miniature Portable Wireless Thermocouple Connector and Data Logger, Records Over 65,000 Process Temperature Data Points The Smart Connector ™

Portable Data Logger OM-SQ2020 Starts at $2445

*MWTC-D Series $150

Visit omega.com/mwtc-d ®

Because of transmission frequency regulations, these wireless products may only be used in the United States and Canada (915 mHz models) or Europe (868 mHz models).

Visit omega.com/om-sq2020

omega.com ®

*PATENT PENDING

© COPYRIGHT 2012 OMEGA ENGINEERING, INC. ALL RIGHTS RESERVED

Our STRIDE family of industrial grade unmanaged Ethernet switches and media converter is specifically built for industrial environments. Install Stride switches and your Ethernet control network will maintain more consistent cycle times even under heavy I/O and data exchange. The aluminum-housed models offer a wider operating temperature range (-40 to +85 deg. C).

Advanced Industrial Hardware • All 10/100BaseT RJ45 ports are auto-detecting, auto-crossover and auto-polarity • Redundant power inputs with surge and spike protection • Optional 100Mbps multimode fiber optic port for distances up to 4km • NEW! SC (push-pull type) fiber optic connector models, in addition to ST (slotted bayonet) style versions

CHECK OUT PRICES ON ETHERNET SWITCHES Product Description 5-port Ethernet switch with five 10/100BaseT RJ45 Ethernet ports

$

8-port Ethernet switch with eight 10/100BaseT RJ45 Ethernet ports

$

5-port Ethernet switch with four 10/100BaseT RJ45 Ethernet ports and one 100BaseFX fiber optic port

$

Ethernet Isolation -1500 VRMS 1 minute Spike protection - 5,000 watts (10x for 10 uS) UL (CUL) listed and CE certified Hazardous locations rated for Class 1, Div. 2

STRIDE METAL MODELS Price/Part Number $

199.00 SE-SW5U-WT

SE-SW5U

172.00

$

259.00 SE-SW8U-WT

172.00

$

259.00 SE-SW5U-ST-WT

$

399.00 SE-SW9U-ST-WT

SE-SW8U

SE-SW5U-ST

$

242.00 SE-SW9U-ST

Ethernet-Fiber converter with one 10/100BaseT RJ45 Ethernet port and one 100BaseFX fiber optic port

$

162.00 SE-MC2U-ST

AutomationDirect prices are U.S. published prices as of October 2011. Prices subject to change without notice.

www.automationdirect.com/ethernet Also Available

True Industrial Design • • • •

99.00

9-port Ethernet switch with eight 10/100BaseT RJ45 Ethernet ports and one 100BaseFX fiber optic port

Real-time Performace • Store and forward wire speed switching - no delays • Full-duplex operation with flow control (no collisions!) • Auto crossover (MDI/MDIX) and auto polarity

AutomationDirect STRIDE PLASTIC MODELS Price/Part Number

www.automationdirect.com Go online or call to get complete information, request your free catalog, or place an order.

1-800-633-0405 Shielded Cat5e cables starting at: $5.00

Super Ion Air Knife™ Produces a laminar sheet of airflow that floods an area or surface with static eliminating ions.

Super Ion Air Wipe™ The uniform 360° ionized airstream neutralizes and cleans continuously moving surfaces.

Prevent Shocks, Jamming, Tearing and Static Cling! When the humidity is low, static electricity problems will happen. • Materials tear, jam or curl

• Hazardous sparks or shocks

• Webs and films cling to themselves

• Product clings to itself, rollers, machine beds

• Electronic sensors fail, making false readings

• Dust attraction ruins surface finishes

Ion Air Gun™ Eliminates static and dust from parts prior to assembly, packaging, painting or fi nishing.

EXAIR manufactures a complete line of static eliminators to remedy common static problems. Many use our engineered airflow products to minimize air use and noise while delivering maximum results by moving more static eliminating ions to the product surface.

Ion Air Cannon™ Ideal for hard to reach spaces or confi ned areas that require a concentrated ionized flow.

Watch Our Brief Video! How To Get Rid of Static & Dust! Ion Air Jet™ Delivers a concentrated blast of ionized air prior to shrink wrapping, packaging and printing.

www.exair.com/14/47014a.htm Ionizing Bar If you would like to discuss an application or request a catalog, contact:

Eliminates static cling, dust attraction and jamming on paper, plastics and fi lm.

Manufacturing Intelligent Compressed Air Products Since 1983 11510 Goldcoast Drive • Cincinnati, Ohio • 45249-1621 • (800) 903-9247 • fax: (513) 671-3363 E-mail: [email protected] • www.exair.com

@EXAIR

www.exair.com/14/470a.htm

Name Peter Simonsen Job Title Design Engineer, Embedded Software Area of Expertise Renewable Energy LabVIEW Helped Me Perform real-world simulations with total control of the application Latest Project Develop a test architecture for verification of wind turbine control systems

NI LabVIEW

LabVIEW makes me better because I can

SIMULATE real-world systems

>>

Find out how LabVIEW can make you better at ni.com/labview/better

©2010 National Instruments. All rights reserved. LabVIEW, National Instruments, NI, and ni.com are trademarks of National Instruments. Other product and company names listed are trademarks or trade names of their respective companies. 2811

800 453 6202

Accelerating Engineering Innovation

Contents

January 2012 vol. 67 no. 1

www.designnews.com

38

34

52

Cover Story 34 Ethernet Converges on Factory Automation Ethernet adoption drives development of infrastructure to support completely networked, plant-wide architectures from field devices up to management level. By Al PrEshEr

Features 38 Micro hybrids hit the road Starter motors with automatic starting capabilities will hit the auto market in a big way in 2012. Within 15 years, every new vehicle could offer “start-stop.” By ChArlEs J. MurrAy

46 Adhesives Put New Twist on Fastening

52 Crowdsourcing Creates CAD Groundswell

MAde BY MonkeYs

18 Are Front-load Washers less reliable?

While user input has the potential to boost innovation, manufacturers have been slow to embrace the strategy.

Bill Schweber’s washer started to shake due to a cracked spider, and repair costs were as much as the machine itself.

By BETh sTACkPolE

C A P tA i n h Y B r i d

Columns

20 is the EV1 still the Best Electric Car Ever? Some engineers still consider the EV1 to be a monument to the art of automotive engineering.

Wolfe’s den

12 2012: year of the Engineer Designers will no longer be the Rodney Dangerfield of the tech world.

By ChArlEs J. MurrAy

By AlEXANDEr WolFE

sherloCk ohMs

58 The Case of the Faulty spring Clutch

P e t ro s k i o n e n g i n e e r i n g

14 Normalization of Deviance

Engineers are demanding multifunction adhesives and more rugged fasteners.

Normalized deviance has plagued the oil drilling industry, where at least some companies have allegedly let the financial bottom line dominate decision-making.

By ANN r. ThryFT

By hENry PETroski

This problem with faulty springs revealed the problem with conventional-wisdom solutions. By JEFFrEy ANTMAN, PE

continued >

Cover Image: Debee rommel

w w w. d e s i g n n e w s . c o m J a n u a r y 2 0 1 2 D e s i g n N e w s

5

mouser.com

AS9120A Certified Distributor

Semiconductors and electronic components for design engineers.

Authorized Distributor

Highest Standard for Quality and Control. Mouser has high-level traceability and anti-counterfeit controls to serve aerospace, industrial, and commercial products. Your one source for What’s Next. ■ Widest selection of newest products

■ Fastest introduction of new products

■ Millions of products online

■ 1715+ microsites and resources

■ Localized global support

■ Accurate, same-day shipping

mouser.com |

Mouser and Mouser Electronics are registered trademarks of Mouser Electronics, Inc.

The Newest Products for Your Newest Designs

®

Contents > continued

7

GADGET FREAK

64 The Frankenkindle: An Easier-to-Use Kindle

Supplements

64

Fluid Power/Power Transmission

Glenn Johnson took the controls from a children’s V.Reader and routed them into the Kindle’s interface board to create this easier-to-use Kindle.

Find stories on a pneumatic driver for an artificial heart, and how longtravel piezomotors are being used for applications formally addressed by magnetic motors.

Departments 22 Data Measurement & Analysis

What’s the Noise in a Signal-toNoise Ratio?

24 Mechatronics

59 Social Engineering

These stories also appear online at www.designnews.com.

Standards, Security Add 2012 Angst

60 Design Decisions

DESIGN NEWS® (ISSN 0011-9407) is published monthly by UBM Electronics, 600 Community Drive, Manhasset, NY 11030; 516-562-5000. Periodicals postage paid at Manhasset and at additional mailing offices. SUBSCRIPTIONS – Free to qualified subscribers as defined on the subscription card. Rates for non-qualified subscriptions, including all issues: U.S.A, $150.00 one year, $250.00 two years, $300.00 three years; Canada, $184.90 one year, $314.90 two years (includes 7% GST, GST# 123397457); Mexico, $172.90 one year, $295.90 two years; Foreign air expedited $323.90 one year, $579.90 two years. Except for special issues where price changes are indicated, single copies are available for $10 U.S.A and $15 foreign. For telephone inquiries regarding subscriptions 763-746-2792. Email: [email protected]. CHANGE OF ADDRESS – Notices should be sent promptly to DESIGN NEWS® P.O. Box 47461, Plymouth, MN 55447 – Please provide old mailing labels as well as new address. Allow two months for change. NOTICE – Every precaution is taken to ensure accuracy of content; however, the publisher cannot accept responsibility for the correctness of the information supplied or advertised or for any opinion expressed herein. POSTMASTER – Send address changes to, DESIGN NEWS® P.O. Box 47461, Plymouth, MN 55447, Canada Post: Publications Mail Agreement 40685520. Return undeliverable Canadian addresses to: Pitney Bowes, P.O. Box 25542, London, ON N6C 6B2. Printed in U.S.A. Copyright 2011 by UBM Electronics. All rights reserved. Reproduction in whole or part without written permission is prohibited.

What to Consider When Choosing a Rotary Encoder

Theory & Practice

61 Design Engineering

26 Green Scene Environmental News Engineers Can Use

Products

Best of the Engineering Marketplace

28 News Trends, Developments, Breakthroughs

ICP DAS USA

1-888-971-9888

Data Acquisition - Automation - SCADA -Data Loggers Protocol Converters- Network Switches & Gateways Wireless products - Motion

Touch Screen PLC

Industrial Ethernet

Remote Data Acquisition

FREE Ladder Logic C Language Development Software

Din Rail Mountable & Designed for Extreme Temperatures

Compact and Din Rail Mountable Modules in RS-485, Modbus, CANbus & More

Starting at $199

Starting at $99

Starting at $139

Protocol Converters

SCADA Software

Programmable Controllers

Convert Modbus, Profibus, CANBus, Ethernet/IP, HART & More

PC Based Control & Monitoring Software. Downloadable Free Trials Available

Automation Controllers in CE.NET, Linux, XP Embedded & more, with SDK.

Starting at $129

Starting at $399

Starting at $1199

Los Angeles, CA

www.icpdas-usa.com

Real parts. Really fast. Simply upload your 3D CAD model, and choose the best option for your needs.

CNC Machining in 1–3 days. Best for 1–10 parts. Priced from $95.

Injection Molding in 1–15 days. Best for 10–10,000+ parts. Priced from $1495. Choose from hundreds of engineeringgrade resins, including HDPE, Polypropylene, ABS/PC, Acetal, PBT, Polycarbonate, Nylon 66, Polyamide and LPDE.

Choose from 30 different materials including ABS, Nylon, PC, Delrin, PEEK, ULTEM, aluminum and brass.

It’s easy to work with Proto Labs. Choose CNC machining or injection molding, whichever is best for your project. Upload your CAD model and receive an automated, interactive quote in hours. Once approved, our cluster computing technology and automated manufacturing systems will deliver real parts using real materials in as little as one day. And that’s the real story. ©2012 Proto Labs, Inc.

ISO 9001:2008 Certified

Check out our video design tips!

Get Your Protogami

Our newest design aid is a cool kaleidocycle that shows the effect of materials on finishes. Visit www.protolabs.com/parts today and request your free Protogami! Enter code DN12A.

Call 877.479.3680 or visit www.protolabs.com

NOw ON

.com

automation & control

the top trends of 2011

Ethernet’s move to the industrial automation space is gaining momentum, as engineers make the conversion from the fieldbuses of the 1990s to networks that unify the front office and factory floor. http://bit.ly/susTge

It was a year chock full of cutting-edge technology, and our editors have taken a look back at some of the best in robotics, autos, and materials. Also, be sure to turn to our news section, (pg. 28), where we look ahead to what’s in store for 2012.

gadget Freak

robotics:

Our gadget freak slide show reveals a host of interesting projects, ranging from an interactive beer pong table to jet engines made out of junk, and even a 3D tic-tactoe game. http://bit.ly/t61qY2 Engineering Materials

Is a wave of aerospace component manufacturers buying composite makers about to break? Two acquisitions in the last month and one earlier in the year may portend a trend. http://bit.ly/vnREpH

The five most important robotics trends of 2011 enable volume manufacturing, and aim at further integration of robotics with machine vision and automated systems.

Using virtual-holographic 3D imagery, Infinite Z’s new zSpace immersive 3D environment lets users interact and explore 3D models as if they were real, physical objects. http://bit.ly/tJ2891 Mechatronics Zone

Industrial robots that do welding and metal fabrication are getting both a lot smaller and a lot larger, depending on the size of the company using them and the type of welding configurations they need. http://bit.ly/sajZTw

Product catalog

Maxon’s Brushless EC 8 Motor

Maxon’s new brushless dc motor offers continuous torque up to 0.95mNm, nominal speed up to 80,000rpm, and an efficiency rating of 70 percent. The motor is available with or without Hall sensors and with 6V, 12V, and 24V windings. This motor was produced according to rigid Medical Standard ISO 13485 and is for applications such as sampling robotics, portable analyzers, metering systems, instrumentation, or inspection robots. http://dn.hotims.com/40992-500

automotive:

Editorial WEbcast

An agreement with 13 automakers to increase fuel economy to 54.5 mpg by model year 2025 meant little to consumers in 2011, but will be huge for the engineers designing next-generation autos. http://bit.ly/tPZ39i

The five most important materials trends of this past year enable volume manufacturing. Read more at: http://bit.ly/sNpSv4 Mechatronic solutions: smart integrated actuator technology View now at: http://bit.ly/rJUvk3

Smart actuators incorporating integrated controls and network connectivity options are finding their niche in machine control applications. The key is a single mechanical actuator-motor with onboard electronics that can provide both a broader set of controls and the simplicity of an integrated solution.

CONNECT wITH US

Design News’ System & Product Design Engineering group: http://bitly.com/designnewsLI

RESOURCE CENTER

http://bit.ly/sZTnFy

Materials:

cad/caM corner

ONLINE

Design News’ general Twitter feed: http://twitter.com/designnews Design News’ Sustainable Engineering Twitter feed: http://twitter.com/awolfe58

http://on.fb.me/fanpagedn Get Design News’ RSS feeds at http://www.designnews.com/rss/ and sign up for e-mail newsletters at http://www.designnews.com/register.asp

Energy Efficiency: Motors & Drives

Energy and Efficiency in Motors and Drives looks at the changes that have occurred in recent years. Plants are much more concerned these days about energy consumption. And energy-efficient equipment sends savings to the bottom line. In addition to the positive value of savings from efficiency, plants are also concerned about their carbon footprint. For most companies, the reduction in energy consumption has become an overriding goal. Efficient motors and drives contribute to the goal. http://dn.hotims.com/40992-501 aPPlication notE

Top 5 Things You Need to Know When Selecting Directional Valves

Selecting the right valve to control system pressure, direction of flow, and rate of flow is crucial when designing fluid power circuitry. This online resource features the top five things that must be considered when specifying directional valves for any pneumatic application. http://dn.hotims.com/40992-502

w w w. d e s i g n n e w s . c o m J a n u a r y 2 0 1 2 D e s i g n N e w s

9

BRAND DIRECTOR Al Schmidt 972-980-8810 CONTENT DIRECTOR Alexander Wolfe 516-562-7386 MANAGING EDITOR Jennifer Campbell 781-869-7974 Charles J. Murray, Senior Technical Editor Ann R. Thryft, Senior Technical Editor Rob Spiegel, Senior Editor Lauren Muskett, Assistant Editor TECHNICAL SPECIALTIES CAE Software & Hardware: Beth Stackpole [email protected] Electronics & Test: Charles J. Murray [email protected] Fluid Power/Automation & Control: Alexander Wolfe [email protected] Materials & Assembly: Ann R. Thryft [email protected] CONTRIBUTING EDITORS DATA MEASUREMENT & ANALYSIS/ Jon Titus, [email protected] PRODUCTION Donna Ambrosino, Production Director

maxon motor control

Maintaining control has never been easier.

UBM DESIGN CENTRAL Gene Fedele, Vice President/Design Director David Nicastro, Creative Director Debee Rommel, Creative Director Giulia Fini-Gulotta, Art Director Adeline Cannone, Production Manager Laura Alvino, Sr. Production Artist Yoshihide Hohokabe, Production Artist Diane Malone, Production Artist BUSINESS OFFICE Colleen Heckman, Project Manager Esther Aronov, Marketing Project Manager DESIGNNEWS.COM Brian McAvoy, Director, Interactive Media 781-869-7964 U.S. SALES REPRESENTATIVES IL/IN/KY/MI/OH/ON/WI Jami Brownlee 815-893-6052 DC/FL/GA/IA/KY/MD/MN/NC/PA/SC/SD/VA Doug Robertson 781-869-7966 CT/DE/MA/ME/NH/NJ/NY/RI/VT Julie Simoneau 781-869-7962 AZ/CA/CO/ID/MO/NV/OK/OR/TX/WA Chris Bombarger 512-249-0221 REGIONAL/SALES MANAGER CUSTOM PUBLISHING Mike Paul 781-869-7965 INTERNATIONAL REPRESENTATIVES UK Stephen Waddell 011 44 1322 437091 GERMANY Erhardt Eisenacher 011 49 2 28 65 0013 FRANCE Alain Faure 011 33 1 53 21 88 03 JAPAN Toshiyuki Uematsu 011 81 3 5775 6056

If decentralized drive intelligence is called for, maxon motor control provides the answer: All speed and positioning controllers are designed to match with DC motors up to 700 watts power. The EPOS2 positioning controller can be used with CANopen and Interpolated Position Mode. maxon motor is the world’s leading supplier of high-precision drives and systems of up to 500 watts power output. Rely on the quality of the highly specialized solutions which we develop with and for you. www.maxonmotorusa.com

UBM ELECTRONICS MANAGEMENT TEAM CEO, UBM ElECTRONICs/UBM CANON (pUBlIshING) Paul Miller ChIEf INfORMATION OffICER Brent Pearson sENIOR VICE pREsIDENT David Blaza sENIOR VICE pREsIDENT Of CONTENT Karen Field VICE pREsIDENT Of fINANCE Jean-Marie Enjuto VICE pREsIDENT Of pARTNER sERVICEs & OpERATIONs Barbara Couchois VICE pREsIDENT Of MARkETING Felicia Hamerman DIRECTOR Of AUDIENCE ENGAGEMENT AND ANAlyTICs Amandeep Sandhu Design News ® is a member of UBM Electronics 33 Hayden Ave., Lexington, MA 02421 www.designnews.com Subscription Inquiries: 847-559-7597 Reprints: Wrights Media 2407 Timberloch Place, Suite B The Woodlands, TX 77380 281-419-5725

D e s i g n N e w s J a n u a r y 2 0 1 2 w w w. d e s i g n n e w s . c o m

In certain environments, HBLEDs may be subject to corrosion… and failure. While this doesn’t happen too often, it is something you should be aware of if the high-brightness LEDs (HBLEDs) in your application will be exposed to the air without the benefit of a suitable enclosure. Perhaps most surprisingly, this problem does not occur with the less-expensive, lowerbrightness “commodity” LEDs that are encased in hard epoxy such as those below.

This is a potential problem in environments with high concentrations of hydrogen sulfide and other reactive gasses. Sometimes these gasses will evaporate from nearby sulfur-treated, rubber-based materials 2 at high temperatures and contaminate the LED; they can also be present in air pollution, near certain industrial processes or over liquids. Metal on the LED’s interior leadframe will react with the gasses, accelerated by the die’s high temperature, and start to corrode the device from the inside-out.

Recently, a manufacturer supplied me with a novel product to evaluate: a low-profile, self-adhesive strip of high-quality HBLEDs to be used for outdoor, marine and industrial applications. My concern was the gas permeability of the overmolded silicone-encapsulated HBLEDs. I thought of a convenient, albeit unscientific, method of testing the product. It just so happened that I needed a little extra light for my aquarium. The HBLED strip was mounted on Figure 1 – Common epoxy encapsulated LEDs the underside of the cover, 10 cm above the surface of the Clear or colored epoxies certainly do have many desirable water. It was subjected to warm water vapor, a small amount characteristics: mechanical hardness (reducing the likelihood of condensate and accumulated gasses. The water is slightly of LED die or bond wire damage due to rough handling), saline, with a salt concentration of 20 ppt (seawater is about moldability (the package itself can be formed into a lens), 35 ppt). Three green spotted pufferfish swam underneath, and low-cost. However they are often not suitable for carefully monitoring the results. encapsulating HBLED die. HBLEDs get quite hot, and After 30 days of continuous operation, some of the epoxies have low melting temperatures. Furthermore, HBLEDs began to fail. As you can see in the photographs ultraviolet and intense blue light tends to make these below, the reactive chemicals quickly diffused through the epoxies brittle. The material turns brown and eventually silicone encapsulate and attacked the LED’s leadframe and opaque—thus limiting an HBLED’s output and lifetime. bond wires. Several developed internal current paths across This is problematic for high-output white LEDs, since they bridges, current levels increased and light output decreased. are constructed from blue-emitting die. 1

Today, silicone is the typical encapsulant for highbrightness and high-power LEDs. Silicone can withstand high temperatures and has excellent optical transmittance across the entire visible spectrum, even down into the UV-A range (400 nm – 315 nm). On white HBLEDs, sometimes the yellow phosphors which cover the blue die are mixed into the silicone before it is deposited into the package cavity and cured. Despite the fact that relative to epoxy, silicone enhances an HBLED’s performance and extends its lifetime, it presents two hazards. The first is mechanical damage to the LED die and its internal connections. We advise people not to touch and never to poke the surface of a silicone-encapsulated HBLED. Silicone is soft and pliable; tiny bond wires are easily dislodged. The second, less-known hazard is corrosion. Silicone is a wonderful sealant; it’s used to make gaskets and glass aquariums. But it is also gas-permeable. 1

Photo by Afrank99

Figure 2 – Going, going… gone. (Internal lead frame corrosion)

Silicone is an outstanding encapsulant, but you must understand its limits. In this case, the LEDs would have fared better if a secondary glass or acrylic window were placed above them. If you’d like more information on high-brightness LEDs, visit our website (www.em.avnet.com/LightSpeed) or send a note to [email protected]. Your questions and comments are always welcomed. 2

Cary Eskow is Global Director of the Solid State Lighting and Advanced LED business unit of Avnet Electronics Marketing. An ardent advocate of energy efficient LED-based illumination, he has worked closely with LED manufacturers, advanced analog IC and secondary optics vendors since his first patent using LEDs was issued two decades ago. Avnet works with customers through their national team of illumination-focused sales engineers who are experienced in thermal, drive stage and optics design. Prior to his LED lighting focus, Cary was Avnet’s technical director and managed Avnet’s North American FAE team. To submit questions or ideas, e-mail Cary at [email protected]

Rubber is sometimes manufactured with sulfur in the vulcanization process

To learn more about designing an LED-based illumination system, go to:

www.em.avnet.com/LightSpeed

12

Wolfe’s Den

Alexander Wolfe, Content Director, [email protected]

2012: Year of the Engineer I’m optImIstIc that the new year will bring newfound respect for engineers, and not of the Rodney Dangerfield variety. I think we’re finally on the verge of getting some credit from the general public for the tough work we do. The first impediment towards elevated esteem is that the average person doesn’t really know what an engineer is or does. Truth be told, I’m not so sure we’re all agreed on it either. When I was at school, we were told that engineers found cost-effective solutions to problems. That’s sometimes but not always true — think defense contracting. In any case, it falls far short of the mark. The always-reliable Wikipedia defines an engineer as “a professional practitioner of engineering.” Gee, thanks, crowdsourcers. Dictionary.com says it’s a person “skilled in the design, construction, and use of engines or machines.” I guess that finally puts the EEs in their place. Henry Petroski made a cogent point in his Design News column, “Distinguishing Between Scientists & Engineers” (October, pg. 16). He noted how newspapers consistently use “science” when they mean “engineering.” Thus scientists become the embodiment of white-coat wisdom and us engineers are back in Dangerfield territory. The reason I think this is finally changing is due to another misconception, but one which works in our favor. It involves Steve Jobs, whose biography was the top selling book of 2011. Most folks mistakenly assume he was an engineer. In fact, he was a college dropout, as is Bill Gates. (Apple cofounder Steve Wozniak is an engineer, having returned to school and earned his degree in 1986.)

D e s i g n N e w s J a n u a r y 2 0 1 2 w w w. d e s i g n n e w s . c o m

Steve Jobs is revered by the general public. Clearly this is not because of his personality — he was famously a bully, which is inappropriate, though not rare, in titans of industry. It’s because, although he wasn’t an engineer, he “engineered” stuff through managing the design process performed by engineers working for him. Most importantly, he frequently used the one word that’s become anathema within the engineering culture where adding features is thought to be a positive, as well as in the broader culture where collaboration necessitates acquiescence to groupthink. That word was “no.” Saying no is the most effective way of keeping an engineering project within its design constraints, of reining in the cost of bills of materials, and of generally keeping schedules on track. Subjectively, I believe it also enforces an elegance of design which began to flourish in the arts with Bauhaus and Deco. These in turn lead to streamlining, which reached its apex in the era of locomotives. They also begat Harley Earl, the legendary General Motors designer of the mid-twentieth century. Collectively, those influences are reflected in the iPhone and iPad. They’re also fusing into the miniaturized design we’re working on today. I believe miniaturization itself enforces enticing packaging. Petroski writes that engineers exploit scientific principles and discoveries.That’s true, but I think the best definition of good engineering can’t be captured by a dictionary. Rather, you just know it when you see it.

Follow us on:

Technology by THE INNOVATORS

Efficient Automation Efficient  Increased precision and quality through synchronization and real-time capabilities  Reduced costs through scalability and design freedom – PC-based or embedded  Investment security through openness and full compatibility  Increased productivity throughout the entire life cycle through intelligent service and diagnostic functions  Space-savings through compact systems and decentralized topologies

Perfection in Automation

www.br-automation.com

1414

PETROSKI ON ENGINEERING Normalization of Deviance LAST SPRING AND SUMMER, while oil gushed

into the Gulf of Mexico, much of the media coverage following the fatal explosion on the drilling rig Deepwater Horizon focused on the blowout preventer located a mile below the surface. As its name denotes, the device’s function was to prevent exactly the kind of blowout that did occur. It did not work properly because some pipe from the runaway well was forced upwards into the preventer and jammed the mechanism. Over a 25-year per iod, a Henry Petroski pre-accident survey had found blowout preventers on about 15,000 other wells had to be activated in an emergency only 11 times. Unfortunately, in five of those cases the preventer failed, as it did in the Gulf. This 45 percent historical failure rate did not jibe with the 0.07 failure rate claimed during the government-mandated testing of blowout preventers. Even as lax oversight and testing procedures were being called into question, the oil industry was using this low failure rate to argue for less frequent testing of the complex system of valves and rams that were the last line of defense against a blowout. It was estimated that reducing testing requirements could save oil companies almost $200 million per year. A blowout preventer is also an expensive piece of equipment to maintain, with an estimated cost of $700 per minute incurred during the time that drilling had to be stopped, the device disconnected and hauled to the surface, repaired, lowered back down, and reattached to the wellhead. The economics of the situation clearly argued against a conservative maintenance regimen and promoted a culture of risk taking.

In the case of the oil company BP, whose gulf operations were directed out of Houston, the culture that developed around deepwater drilling operations was not unlike that of another Houston-based technology. At the outset of the space shuttle program, the total-failure rate of shuttles was estimated by engineers to be 1 percent and by managers to be 0.001 percent. The Challenger accident proved the actual failure rate then to date to be 4 percent, and after the Columbia accident it still stood at close to 2 percent. Repeated negative experiences with eroding O-rings and shedding insulation were not heeded as warnings but taken as signs of the robustness of the space vehicle and promoted a fault-tolerant culture that allowed for what has been called a “normalization of deviance.”

Over a 25-year period, a pre-accident survey had found blowout preventers on about 15,000 other wells had to be activated in an emergency only 11 times. Normalized deviance has also plagued the oildrilling industry, where at least some companies have allegedly let the financial bottom line dominate decision-making. Just as NASA managers were emboldened by two dozen successful shuttle flights before the accident with Challenger and, after the hiatus, another 87 successful missions before the disintegration of Columbia, so the low incidence

Henry Petroski is the Aleksandar S. Vesic Professor of Civil Engineering and a professor of history at Duke University. His latest book is An Engineer’s Alphabet: Gleanings from the Softer Side of a Profession. He can be reached at [email protected]. D e s i g n N e w s J a n u a r y 2 0 1 2 w w w. d e s i g n n e w s . c o m

Enter xx at www.edn.com/info

16

Petroski on Engineering

of needing to call upon the blowout preventer in an emergency promoted a sense of bravado in the operation of offshore oil rigs. It is easy in retrospect to say that the Deepwater Horizon accident did

not have to happen. The design of the blowout preventer should arguably have anticipated that a difficult-to-control well might cause the well pipe to be propelled upwards and buckle and so present a far-from-ideal piping geometry for the

PEM® Brand Captive Panel Screws Ideal for metal panels, pc boards and other thin materials.

PEM brand captive panel screws help keep parts to a minimum while eliminating risks associated with loose hardware that could fall out and damage internal components. These panel fastener assemblies offer a wide selection of product types and features to meet most application requirements.

PEM® Skirted Shoulder Identifier (registered trademark)

“Designed for” • corrosion resistance • tool or hand assembly • flush-mounting • low profile • UL® approved • locating pin • color coding • anti cross-threading • spring loaded • floating for misalignment

Ask about our PEM® C.A.P.S® color capabilities

Mounting styles: • Self-clinching • Broaching • Surface Mount • Floating • Flaring

Go to www.pemnet.com and select the product literature tab to view PEM Bulletin PF

Drive Types: • slot/Phillips • Phillips • slot • six-lobe/slot

70 YEARS

OF EXCELLENCE

1942-2012

www.pemnet.com

D e s i g n N e w s J a n u a r y 2 0 1 2 w w w. d e s i g n n e w s . c o m

352 ©2011

so-called blind shear rams in the blowout preventer to deal with. There evidently were warnings that the well being drilled was a difficult one to control, and there were reported irregularities in the condition and status of safety devices and warning systems on the rig. However, instead of these precursors of failure being heeded, they were ignored or accepted as business as usual. In the wake of the spill, the oil company BP, the rig’s owner-operator Transocean, and the contractor Halliburton argued among themselves about who was responsible for the accident.

Even as lax oversight and testing procedures were being called into question, the oil industry was using this low failure rate to argue for less frequent testing. The presence of the blowout preventer provided a sense of backup security, in that it presumably could be called upon to control the well should anything go drastically wrong on the rig. This proved to place unwarranted confidence in an unreliable piece of complex machinery. The relative liability of the companies involved in the drilling operation gone amuck will no doubt continue for some time to be argued among managers and lawyers and regulators, and the final outcome is likely to be a financial settlement that will not get to the heart of the matter. What appears to be clear about the technical, economic, regulatory, and environmental tragedy is that the root cause of the Deepwater Horizon oil spill was at least as much a human problem as a mechanical one. DN

as tough as they come

18

MADE BY

MONKEYS

http://bit.ly/MadeByMonkeys

Potting/Encapsulation Serviceable Up To 500ºF

Are Front-Load Washers Less Reliable?

EP36 • Superior electrical insulation properties • B-stage epoxy system

Hackensack, NJ 07601 USA +1.201.343.8983 [email protected]

www.masterbond.com

Our 7-year-old midrange Sears front-loading washer started to shake. Long story short, the bearing or support spider was starting to fail. We couldn’t figure that out until after it was disassembled in repair — it turned out the spider had indeed cracked. The repair required replacing the tub, drum, and spider. That’s $1,000 in parts alone. It took two guys and two hours. Luckily, the unit was still within the 10-year warranty, so all I had to pay was $130 in labor. That’s OK, since the washer cost $1,000 — the same cost as the repair parts. The repairman — who has 20 years of experience — told me these front loaders are much less reliable than top loaders. So my question is — One: is the reliability difference inherent in the mechanics of a front-loader design? Or two: is it just due to inadequate design and shortcuts? Perhaps three: no design margins, or incorrect choice of materials, or material quality control, or poor assembly. I’m betting on points one, two, and maybe three. Or, are manufacturers taking the opportunity of the trend toward supposedly efficient front-loaders to design-down their machines? Are they trying to cut manufacturing costs while making it up in service calls? Here’s why I wonder about that last point: my machine has a 10-year warranty. But the more recent ones come with a one-year warranty. A one-year warranty is pretty much useless in the real world. I guess I’m one of the very lucky ones with the longer warranty of an older machine. This washer has not had a hard life. It’s just the two of us. Our previous unit, the revered and venerable Maytag A608 top-loader, is well known as one of the most reliable washers ever made. That judgment call came from Consumer Reports, other sources, and user groups. We had it for 25 years, through two kids. All it ever needed was two belt replacements at just $100 a pop. Finally, the main bearing failed. But hey, after kids and 25 years, that’s darn good. With the new ones, you can get a service contract for $140 per year. That’s more than 10 percent of the cost of the machine. Front loaders also have another issue: the repeated on/off hard cycling of the fill valve procures tremendous water hammer, which is both very loud and can cause pipes (both new and old) to develop micro-cracks due to repeated motion. Those micro-cracks can grow into big cracks. The solution is a $15 water-hammer arrestor on each fill line — if you know to do it. If not, you’ll have leaking pipes and joints, or else a major leak in a few years. So, I’m wondering if the question of front vs. top-loader mechanics has become a matter of product down-designing. — BILL SCHWEBER

Made by Monkeys highlights products that somehow slipped by the QC cops. E-mail your examples to Rob Spiegel at [email protected]. D e s i g n N e w s J a n u a r y 2 0 1 2 w w w. d e s i g n n e w s . c o m

SolidWorks is a registered trademark of Dassault Systèmes. ©2011 Dassault Systèmes. All rights reserved.

LOOKING FOR DESIGNERS TO PUSH THIS BABY P R OJECT 3: HOT R OD BABY B U G GY Help host Jeremy Luchini design the first hardcore baby buggy using ® SolidWorks . You’ll share ideas, comment on designs and vote on key decisions throughout the project. If you think you’re ready, let’s go design. Watch. Share. Vote. LetsGoDesign.tv

20

Captain Hybrid designnews.com/blog/Captain_Hybrid

Is the EV1 Still the Best Electric Car Ever? Some engineers still consider the EV1 to be a monument to the art of automotive engineering. By CHARLES J. MURRAY, Senior Technical Editor, Electronics & Test

EvEn today, if you want to make someone’s blood boil, there’s a good chance you can do it by saying, “GM EV1.” For many, the subject still conjures up images of truckloads of cars being hauled off to a crusher. Still, some engineers who have torn down and evaluated electric cars have a different viewpoint. They see the EV1 as a monument to the art of automotive engineering. If it used today’s lithiumion batteries, they say, no electric vehicle ever made could touch it. “When it comes to pure electric vehicles, the EV1 is still the best that’s been built in the last 15 years,” says one engineer, who didn’t want to be named for competitive reasons, but who has torn down and evaluated every production EV that’s been made since the early 1990s. “The EV1 was a fully developed, all-around vehicle. Today, no one has the resources to do what GM did.” For those who don’t remember it well, here’s a short primer on the EV1. Introduced by General Motors (GM) in 1996, the EV1 was a two-seat electric coupe that was designed from the ground up with the best technologies available at the time. It was one of the first vehicles to use an aluminum space frame, which made it about 40 percent lighter than steel. Engineers then joined the frame with aerospace-grade structural adhesives, thereby eliminating many of the welds. They also made body panels from composites — again, to cut weight —and added a lightweight suspension with help from Lotus Engineering. Moreover, the vehicle had the most advanced power

electronics available at the time. Materials weren’t the only way of boosting the EV1’s energy efficiency, however. Design engineers used lowrolling-resistance tires and sculpted the body down to drag coefficient of 0.195, which is still considered to be the lowest in the history of production cars (http://dn.hotims.com/40992-503). By comparison, the Chevy Volt reportedly has a Cd of 0.28 and the Nissan Leaf, 0.29. Both of those figures are better than the auto industry’s average of 0.35 - 0.45, but still far short of the EV1’s. “It’s better than the Leaf,” our contact told us. “And the Tesla — which is certainly faster but costs $120,000 — still is far less sophisticated than the EV1.” To be sure, not everyone agrees with that assessment. As late as 2008, Time Magazine placed the EV1 on its list of “The 50 Worst Cars of All Time.” What’s more, many EV1 detractors have reasonably pointed out that GM spent between $80,000 and $100,000 per vehicle, which is a debatable figure, but one that nevertheless suggests that a comparison of the EV1 and the Leaf isn’t appropriate. Still, it’s hard to argue that the vehicle’s engineering was far ahead of its time. “Microelectronics, miniaturization, better batteries — all of those things have happened since the introduction of the EV1,” our contact says. “But the results don’t indicate that we’ve gotten that much out of it. Yes, we’ve got better batteries today, but imagine what the EV1 could have done with those batteries.” DN

D e s i g n N e w s J a n u a r y 2 0 1 2 w w w. d e s i g n n e w s . c o m

High-Precision Motion Control High-Accuracy, Zero Backlash Gearhead The CSF-GH Quick Connect Gearhead easily mounts to any servo motor yet maintains all of the benefits of Harmonic Drive™ gearing including 1arc-min accuracy and zerobacklash. A high capacity cross roller bearing is used at the output and is available with either a Shaft or Flange output interface. The gearhead have rated torques of 76 in-lbs to 9,320 in-lbs and peak torques of 343 in-lbs to 46,550 in-lbs depending on size and ratio. Gear ratios of 50, 80, 100, 120 and 160:1 are available.

CSF/CSG Precision Gearheads The CSF and CSG high torque Precision Gearhead Series are ideally suited for robotic and machine tool applications. The CSG delivers 30% more torque and 40% longer life while maintaining zero-backlash, 1 arc-min accuracy, and +/- 5 arc-sec repeatability. An accurate, highly rigid cross roller bearing is built in to directly support the external load. A wide variety of sizes and reduction ratios are available with maximum peak torques ranging from 450 in-lbs. to 60,500 in-lbs.

Power & Precision SHA Hollow Shaft Actuator • High Torque Density

• Brushless Servo Motor

• 1 arc-min Accuracy

• Harmonic Drive™ Gearing

• ±5 arc-sec Repeatability

• Integrated Brake

• High Capacity Output

• 17 Bit Absolute Encoder

Bearing

SHF/SHG Hollow Shaft Speed Reducers Available in a wide range of sizes, these zero backlash, 1 arc-min accuracy Harmonic Drive™ gearheads enable design engineers to pass shafts, wires, tubing, or other components directly through the center of the gear. They incorporate an output flange supported by a large cross roller bearing, providing exceptional moment stiffness and load capacity. The smallest unit has a hollow shaft I.D. of 14 mm and an outer diameter of just 64 mm. The largest unit of the family has a hollow shaft I.D. of 80 mm and has a rated output torque of 1236 in-lbs, and a peak torque of 6175 in-lbs. Gear ratios from 30:1 through 160:1 are available.

Harmonic Drive LLC 800-921-3332 www.HarmonicDrive.net

The new SHA series of Hollow Shaft Actuators has the highest torque density of any actuator in its class, yet provides excellent positioning accuracy. Several sizes are available with output torques up to 30,000 in-lb. These actuators are ideally suited for robotics, automation, machine tool, and antenna positioning applications where performance and reliability are essential.

Call 800.921.3332 www.HarmonicDrive.net

DATA MEASUREMENT & ANALYSIS

Unbelievably useful info on data measurement, collection and analysis from the test expert

What’s the Noise in a Signalto-Noise Ratio? A SIGNAL-TO-NOISE RATIO (SNR)

lets us express the relationship between signal and noise powers and between the root-mean-square (rms) values of signal and noise voltages: SNR (dB) = 10log10(signal power Jon Titus / noise power) SNR (dB) = 20log10(rms signal voltage / rms noise voltage). In an analog-to-digital converter (ADC), noise — or non-signal power — relates to the ±1/2 LSB quantization error introduced by digitizing a signal into discrete steps. The familiar equation below provides the SNR for an N-bit ADC based solely on quantization error for a pure sine wave over the Nyquist bandwidth; DC to fsample/2: SNR (dB) = (6.02 * N) + 1.76. But this value tells only part of the story. ADC noise can arise from another source called effective input noise, created by the ADC’s electronics. And jitter in the ADC clock signal also affects the ADC output. A poorly designed circuit board can let digital noise and other ambient signals couple to the clock signal and cause jitter. You can find the complete rootsum-of-squares SNR equation that

combines quantization noise, clockjitter noise, and effective input noise in the document, “Fundamentals of Samples Data Systems,” by Walt Kester and James Bryant, available at: tinyurl. com/7uaubbt, page 2.72. The authors also show the theoretical basis for the third SNR equation. You cannot overcome effective input noise except by choosing a different ADC that introduces less noise. Proper PCB layout, decoupling, and use of a stable low-noise clock signal can reduce jitter. The overall jitter time combines aperture jitter, which occurs in the ADC’s sample-and-hold amplifier, with jitter in the ADC’s sampling clock signal. The latter jitter usually predominates. Although clock jitter of a few picoseconds might seem to contribute little to a SNR value, keep in mind that the effect of jitter increases with the frequency of an ADC input signal, as shown in the diagram. The SNR value does not include power contributed by harmonics of the signal of interest because you can — and should — eliminate harmonics with an anti-alias filter. If you include power from harmonics (but not DC), you get a signal-to-noise-and-distortion, or SINAD, ratio also expressed in dB. Because a SINAD value includes

Jon Titus, a former designer and chief editor of EDN and Test & Measurement World magazines, remembers when “fast” signals operated at 10 MHz and programs came on paper tape. D e s i g n N e w s J a n u a r y 2 0 1 2 w w w. d e s i g n n e w s . c o m

A Voltage

2222

B

Time t Jitter

Jitter in an ADC causes a large measurement error (∆V) in a signal with a high slew rate (A) when compared with the error caused at a lower slew rate (B), or frequency. Thus jitter can greatly influence high-frequencysignal measurements.

all non-signal energy, it can provide a good indication of actual ADC performance. DN

For More Information: 1. “ADC Input Noise: The Good, The Bad, and The Ugly. Is No Noise Good Noise?” Analog Devices. http://dn.hotims.com/40992-504. 2. “How Quantization and Thermal Noise Determine an ADC’s Effective Noise Figure,” Tutorial 1197, Maxim Integrated Products. http://dn.hotims.com/40992-505. 3. “Understanding the Effect of Clock Jitter on High Speed ADCs,” Design Note 1013, Linear Technology. http://dn.hotims.com/40992-506. 4. Kester, Walt, ed., “The Data Conversion Handbook,” Newnes, 2005. ISBN: 978-0-7506-7841-4.

AU

M

E A

CE

S

S

I

CE

IC L

Control Electronics

Digital Control Systems

mechatronics Mechanical CAD

Electronic Systems

Electromechanics

TU

RI NG

Software

RAPHY ROG XE

S

M

FA

Y

E

C

Mechanical Systems

S

T

U

M AT E R I ALS PR O

AERO SP A

Control Systems

SE

FRESH IDEAS ON INTEGRATING MECHANICAL SYSTEMS, ELECTRONICS, CONTROL SYSTEMS AND SOFTWARE

G

N FE DE

MECHATRONICS IN DESIGN

N

TIVE MO

D

24

TO

M

S

CO

A

N

S CT NSU MER PRODU

Theory & Practice We all know about the gap, now let’s do something about it! THE THEORY-PRACTICE GAP has existed for decades and

each of us needs to bridge this gap in all we do. As control is an essential element in all multidisciplinary systems, let’s start there, and begin to bridge the gap that exists between the theory of control and its digital implementation. Top 10 Lists are always popular, so here is one for classical control. Control Theory for the Practitioner 1. Feedback control is a pervasive, powerful, enabling technology that, at first sight, looks simple and straightforward, but is amazingly subtle and intricate in both theory and practice. 2. In a dynamic system, changes cannot be effected instantaneously, and so an otherwise correct control decision applied at the wrong time could result in catastrophe. 3. Nonlinearities are always present, e.g., backlash, Coulomb friction, saturation, hysteresis, quantization, dead band, and kinematic nonlinearities. A linearized model can be used to approximate a nonlinear system near an operating point. 4. Stability of a dynamic system must be guaranteed. Closed-loop systems go unstable because of an imbalance between strength of corrective action and system dynamic lags. Stable systems must have adequate stability margins to work once built. 5. Stable systems have a frequency response. If a stable linear system has a sinusoidal input applied, then the steady-state output will be a sinusoid of the same frequency, however, the amplitude ratio and phase difference of the two sinusoids are frequency-dependent. 6. The open-loop transfer function is the product of all the transfer functions in the loop, e.g., controller, actuator, plant, and sensor. Compared to the closed-loop system transfer function, the open-loop transfer function is much less complex. The Nyquist criterion and the Root Locus procedure allow one to use the open-loop transfer function to predict closedloop system performance. 7. After stability, performance is everything. Command following, disturbance rejection, insensitivity to modeling errors, and insensitivity to unmodeled high-frequency dynamics and noise are the main reasons for using feedback D e s i g n N e w s J a n u a r y 2 0 1 2 w w w. d e s i g n n e w s . c o m

control, once a system is guaranteed to be closed-loop stable. 8. Time delays can be deadly. Always conserve phase, the equivalent of time delay. Integral control adds 90 degrees of phase lag at every frequency and digital control adds time delay primarily due to D/A conversion. Imagine trying to make decisions using old information. 9. High control gain has lots of benefits, e.g., good command tracking and Kevin C. Craig, Ph.D., Robert C. Greenheck good disturbance rejection. However, Chair in Engineering there are three areas of concern: roll- Design & Professor of Mechanical Engineeroff, saturation, and noise. 10. People’s lives may be at stake. ing, College of EngiThere are no “details” in control engi- neering, Marquette University. neering, as even the most insignificant “detail” may prove to be important. Real control systems must be extremely reliable, especially if people’s lives depend on them. Maybe you know all this, but it is worth repeating. Now, let’s put some of this theory into practice. On designnews. com, you will find a case study that bridges the theory-practice gap regarding something we all need to be able to do: implement speed control of a motor with an attached incremental optical encoder sensor using a microcontroller with a PWM output to drive an H-bridge. It doesn’t get any more down to earth than that, yet this exercise uncovers gaps that are present for many of us. The microcontroller is the widely used, inexpensive Arduino; the motor is a 12V Pitman brushed dc motor; the optical encoder is three-channel with 500 counts per revolution; and the H-bridge is the L298. MATLAB/ Simulink real-time code generation is used. My resolution is to continue bridging the theory-practice gap with articles and website case studies. Happy New Year! DN

designnews.com Visit the Mechatronics Zone for the latest mechatronics news, trends, technologies and applications: http://mechzone. designnews.com

Tough Application Ingenious Solution

Exactly

Mastering challenges together — Rexroth makes it easy to implement automation. Our many years’ experience in a wide range of industries has given us extensive application knowledge. We offer this comprehensive understanding to the tasks you bring us, leading to ingenious solutions. Regardless of the drive technology used, we thought ahead and integrated intelligence throughout. This consistency makes you more efficient — from planning to start-up and daily operation. Your benefits are real: Increased productivity, improved energy efficiency and maximum machine safety. You can count on Rexroth to have the appropriate drive and control solution to meet your needs exactly.

Bosch Rexroth Corporation www.boschrexroth-us.com

26

GreenScene Environmental news engineers can use \\\ By Rob Spiegel, Senior Editor

Ford Builds Seats from Water Bottles

Car2go deploys 300 electric vehicles in San Diego.

Ford is using Repreve fiber in the seat fabric of its Focus Electric car. The fiber is polyester that is made from a hybrid blend of recycled materials, including used plastic water bottles and post-industrial waste. The f iber is 100 percent sustainable, and Ford says that each Focus Electric will keep 22 plastic bottles out of landfi lls.

Car2go Goes All Electric Car-sharing company car2go is deploying 300 allelectric vehicles throughout San Diego. The Daimler North America subsidiary will use smart fortwo electric drive vehicles for its San Diego program. The cars will be available 24 hours a day, seven days a week. Members of the program pay by the minute for the time they use the vehicle.

GREEN UPDATES

In 2009, Ford mandated that fabric suppliers use a minimum of 25 percent recycled content for all 2009 models and beyond. Since then, 37 different fabrics meeting the requirements have been developed and incorporated into Ford vehicles. For electric vehicles, Ford has taken the extra step of requiring 100-percent sustainable fabric.

Nissan & Sumitomo Deliver Low-Cost Quick Chargers In support of the proliferation of all-electric vehicles, Nissan North America will deliver low-cost DC quick chargers for electric cars in the US market. The DC quick charger is being launched as part of Nissan’s global collaboration with Sumitomo Corp. The fi rst installations are planned for 2012. The starting price for the charger will be $9,900, about a third of the cost of models available on the global market, according to Nissan. The charger will come in two models, a version for indoor use, which was designed for fleets such as daily rental cars, and an outdoor model specifically designed for public and commercial charging.

For regular updates on sustainable engineering news, follow Content Director Alexander Wolfe at http://twitter.com/awolfe58.

D e s i g n N e w s J a n u a r y 2 0 1 2 w w w. d e s i g n n e w s . c o m

Sooner or later, we all need to start playing with the big toys...

When that time arrives, check out our line of EC centrifugal fans! • Packaged air movers up to 39.4” (one meter) in diameter • Maximum 22,000 CFM or 7.5” static pressure, fully speed controllable • Direct driven by very efficient EC external rotor motors with up to 8HP capacity • Direct digital control, most sizes equipped with RS485 MODBUS RTU interface

See us at booth 2046 at AHR in Chicago

scan this code with any QR reader on your mobile device to go to our plug fan page or go to our website at info.ebmpapst.us/plugfans

www.ebmpapst.us

28

News Trends \\\ Breakthroughs \\\ Developments

Technologies to Watch in 2012 Here’s what to expect this year in the world of automobiles and robotics. 2011 was a year of innovation and

change in many industries, including the automotive and robotic sectors. Now, Design News looks ahead to the latest trends that will emerge in these fields in 2012 (it’s already proving to be exciting)! Be sure to go to designnews.com to also read about what’s coming up in materials & assembly, automation & control, and design hardware & software.

5 Ways Autos Will Change The trend toward fuel efficiency isn’t going away in 2012, or at any time in the foreseeable future. Because automakers are already on the hook to push their Corporate Average Fuel Efficiency (CAFÉ) to 35.5 mpg by 2016, and 54.5 mpg by 2025, they’re going to be working hard on any

feature that can eliminate even the smallest sip of gasoline. The most effective way to accomplish that is through the introduction of electric cars and hybrids of various types. The innovation won’t stop there, however. In 2012, we’ll see the industry pushing the limits on a number of different fronts. Autonomous driving technologies will become more prominent. EV battery sizes will increase. Multicore processors will make a bigger move into the vehicle. And as that happens, engineers will fret about the electronic complexity that’s taking over the automobile. Here’s a look at the five biggest trends for 2012: 1. Micro Hybrids. The automotive world’s migration to hybrid vehicles

D e s i g n N e w s J a n u a r y 2 0 1 2 w w w. d e s i g n n e w s . c o m

won’t slow down in 2012. Ford Motor Co. will roll out its C-Max hybrid and C-Max Energi plug-in hybrid, while Toyota unveils its Prius PHV. But the show-stealer could be the “micro-hybrid,” or “start-stop” car. The micro hybrid, which has been quietly waiting in the wings for years, will make its biggest move yet in the coming year. Ford, Chevy, Buick, Kia, and others will roll out the technology in 2012, joining a handful of models from Fiat, Volvo, and Alfa Romeo that already have it. At its most rudimentary level start-stop will enable vehicles to turn off their engines while waiting at stop lights, stop signs, or in heavy traffic. Soon, however, it will go beyond that level, enabling engines to shut down while a vehicle is coasting, in some cases as fast as 75 mph. Experts say

With So Many EPIC® Connector Possibilities...

We’ll sniff out the right solution for you.

NEW !

Check out our NEW! EPIC ® ULTRA Housings

Re the sistant env harsh to iron est wat includments: elecer/corring: trica osio & di l noisen, rt

Rectangular

DIN Circular

Commercial MIL

IEC Pin & Sleeve

(Power, Control, & Data)

(Power & Control)

(Power & Control)

(Power)

• # of Contacts: 2 to 280 • Rated Voltage: Up to 1000V • Amp: Up to 82A

• # of Contacts: 2 to 55 • # of Poles: 1+N+PE, • # of Contacts: 6 to 26 • Rated Voltage: Up to 600V • Rated Voltage: Up to 1000V 2+PE, 3 +PE, 3+N+PE • Amp: Up to 46A • Rated Voltage: Up to 600A • Amp: Up to 22A • Rated Amp: Up to 100A

Lapp, the manufacturer of EPIC® Connectors, ÖLFLEX® Cable, and SKINTOP® Cable Glands, understands exactly how our connectors can best satisfy your specific needs.

800-774-3536 w w w. l a p p u s a . c o m

30 News

that the technology will be employed on every new car by 2025, making it impossible for even the most dedicated gasoline burners to avoid it. (Turn to page 38 to read more about start-stop technology.) 2. Bigger Batteries. Pure electric vehicles from Ford, GM, BMW, Tesla, BYD, and Toyota are on their way. As such, lithium-ion batteries will get bigger. Tesla, for example, will roll out 42-, 65-, and 85-kWh batteries for its Model S vehicle. BYD’s e6 EV will use a 72-kWh pack — about three times the capacity of a Nissan Leaf battery. RollsRoyce has also employed a 71-kWh battery in its 102EX Phantom Experimental Electric. “In late 2012 and early 2013, we expect to see the cost of batteries start to decline, as a lot of the new lithium-ion plants come online,” Dave Hurst, senior analyst for Pike Research, told Design News in a 2011 interview. “Once that happens, you’ll see an upward trend in battery size.” 3. Vehicle Autonomy. Full autonomy won’t happen for a long time, but pieces of the puzzle will continue to hit the market in 2012. Ford rolled

Bosch’s start-stop starters can reduce a vehicle’s fuel consumption by 5 percent.

out lane-keeping capabilities in 2011, enabling vehicles to “know” if a drowsy driver is wandering outside the lane markers. Park assist features, which arrived with luxury automaker Lexus in 2006, are growing more commonplace. Now, many automakers are laying the foundation for autonomous technology

with the addition of electric power assist for vehicle steering. Soon, we’ l l a lso see more adaptive cruise control and collision avoidance capabilities. General Motors engineers predict that fully autonomous vehicles will start to hit the road in 2020. “We believe that the world (of driving) The Buick LaCrosse will employ GM’s eAssist technology, wil l be autonomous which enables the vehicle to shut off fuel to the engine on demand,” says Alan during deceleration, and boost fuel economy by 25 percent. Taub, vice president of global research and development for more on the horizon as cameras, vision GM. “There will still be fun-to-drive sensors, radar systems, and lane-keeping situations. People do enjoy driving, but and collision-avoidance systems creep not all the time.” into the vehicle. To deal with it, au4. Multicore Powertrains. Mul- tomotive engineers are learning how ticore processors, already popular in to pack the functionality of 50 processafety-related applications, will make sors into 25. That means more multitheir move into automotive pow- core and new “up-integration” software ertrains in 2012. With fuel economy schemes, such as domain control. To be demands on the rise, automotive en- sure, automakers say these things every gineers have begun looking at direct year, yet the problem persists. Maybe injection, cylinder deactivation, and in 2012, we’ll finally see the new era of knock detection as ways to make en- simplicity. gines more efficient. All would benefit — By Charles J. Murray, Senior from the number-crunching capabili- Technical Editor, Electronics & Test ties of multicore processors. Moreover, hybrid electric vehicles will be employ- The Role Robotics Will Play ing multicore, as well, as a means of The five most important robotics trends handling the mathematical complexities of this coming year will enable volume of parallel powertrains. “Powertrain is manufacturing and greater integration the last frontier in automotive to adopt of robotics with machine vision and aumulticore” Philip Pesses of Freescale tomated systems. Some trends discussed Semiconductor said in a 2011 interview. below outline very targeted applica“Up to now, we’ve been able to get the tions. Yet once again, the developments performance we needed, but single- in each are relevant to other, often very core has been clocking out at 300 MHz, different types of applications, which and powertrain applications need to concern robot design and the design of increase their throughput.” the systems in which they work. 5. Complexity Conundrum. As 1. Convergence. One of the most consumers demand more features and significant trends in robotics will be the engineers comply, automakers face a convergence and integration of multiple dilemma: The number of electronic technologies that will help speed up and control units is reaching the point of automate the factory. ABB’s Automaunmanageability. Vehicles now employ tion and Power World 2011 conference, 35 to 80 microcontrollers and 45 to 70 described in the Design News story pounds of onboard wiring. And there’s “Convergence of Power and Automa-

D e s i g n N e w s J a n u a r y 2 0 1 2 w w w. d e s i g n n e w s . c o m

32 News

ABB Automation & Power World is a comprehensive user’s conference and exhibition that showcases ABB’s extensive automation and power offerings.

tion” (http://dn.hotims.com/40992511), focused on merging power systems with automation, as in smart power grids or factory-wide systems. Midrange robot models increase productivity in material handling, machine tending, and other process applications in factories, as well as related functions in electric utilities. Other key elements that work with robots are distributed control systems and asset optimization software for managing high-voltage circuit breaker performance and availability. 2. Software. The more integrated automated systems become, the more important is the software running them. In the Design News story “In System Integration, Software Rules” (http://dn.hotims.com/40992-512), we learn that improving control now focuses on developing automation system software that helps designers make better use of all the high-steroid hardware available and make automatic systems, well, more automatic. Unifying the development environment, more integration of PCs, and more PC-friendly programming and configuration software are part of this trend. While hardware advances won’t stop, we’re at one of those plateaus where software needs to catch up to what hardware can do.

3. Two-armed Robots. Just like people, robots do things better with two hands. More dexterous robots will be valuable in several applications, from surgery to materials handling, or even picking up samples as they walk across the surface of Mars. A step — perhaps a grasp — in the right direction is the small robot with two arms, two hands, and opposable thumbs described in “Dual-Armed Robot Making InRoads” (http://dn.hotims.com/40992513). At Automate 2011, the SDA5D lifted spherical objects from a table. It’s being adopted in industrial applications from logistics and palletizing to automated assembly and distribution. A larger model is deployed in automotive assembly plants, and by NASA, for space simulation operations. 4.Integrated K inematics. Another way to make robots operate more productively is to make them and the handling systems they are being integrated into more like each other. One method for doing this is to build both from common components and controls. Common design components of both include articulated robots, robots, parallel kinematic systems, gantry systems, and linear axis systems. More integrated control architectures are also a key element, which can reduce component counts and simplify in-system communications. 5. Omni-Directional Movement.

The last major trend may be valuable in more than one area. The Design News story “Japan Defense Ministry Spins Flying Spherical Robot” (http:// dn.hotims.com/40992-514) tells us about the development of a remotecontrolled flying sphere that can move in any direction, on land or in the air, and can alight on, or take off from, surfaces of any shape. Designed by Ja-

The Switchblade “kamikaze” reconnaissance drone, one of the smallest used by Army and Air Force special ops forces in Afghanistan, is still larger at 24 inches than the 16-inch flying sphere from the Japanese Ministry of Defense.

pan’s Ministry of Defense engineers during an aircraft R&D project, the remote-controlled robot can hover like a helicopter, take off and land vertically, and immediately take off again in any direction. Onboard gyro sensors let it right itself if jostled. Aside from unmanned aerial vehicles and other aerospace or military applications, this technology may also have applications for machine vision and other industrial or factory-related uses. DN Robotic servo technology developed by Lenze is used to control KUKA robots, among others.

D e s i g n N e w s J a n u a r y 2 0 1 2 w w w. d e s i g n n e w s . c o m

— By Ann R. Thryft, Senior Technical Editor, Materials & Assembly

Fluid Power/Power Transmission

the Freedom driver is the first Us portable driver designed to power the synCardia total Artificial Heart. it is undergoing an FDAapproved investigational Device Exemption (iDE) clinical study in the United states.

Pneumatic Driver System Provides Bridge to Life SynCardia's portable Freedom driver offers mobility and reliability for Total Artificial Heart recipients. By Al PrEsHEr, ContriBUting writEr

T

he innovative Freedom pneumatic driver from SynCardia Systems is the first US portable driver, weighing just 13.5 lb, designed to power the company’s Total Artificial Heart both inside and outside the hospital. CE-approved for commercial use in Europe and undergoing an FDA-approved Investigational Device Exemption (IDE) clinical study in the US, the new driver is allowing stable Total Artificial Heart [ w w w. des ig n n e w s . c o m ]

patients to wait for a matching donor heart at home and in their communities. Currently, the only FDA-approved driver is a 418-lb hospital driver nicknamed “Big Blue.” Stable patients supported by this driver are confined to the hospital while they wait for a matching donor heart. The average wait was 144 days in 2009. The SynCardia temporary Total Artificial Heart has six moving parts inside the body. Each ventricle has an inflow valve, an outflow valve, and a diaphragm. The unique

design doesn’t require sensors, motors, or electronics of any type inside the body, so there is never a need to re-operate to repair faulty electronics. The only electronics needed are in the pneumatic driver which powers the heart and monitors blood flow. It is located outside the body. How it works

“Bimba’s cylinders are used as a driver and are actually actuating the diaphragm inside the artificial ventricles surgically

J an uary 2012 f luid p o we r / p o we r tr ans mis s io n / a s up p le me nt to de s ign n e ws F1

Fluid Power/Power Transmission phragms sit inside the plastic ventricles which form the artificial heart, but are actually just static components until they are connected to the external driver. The driver is connected to the heart using two small air tubes, called drivelines, that exit just below the patient’s rib cage through the upper abdomen. The drivelines are then connected to the cylinder which effectively is pumping the artificial heart by actuating. The cylinder pumps the diaphragms of the artificial heart, circulating blood through a patient’s entire body much like a natural heart. Rhythm of the heaRtbeat the total artificial heart from SynCardia eliminates the symptoms and source of endstage biventricular failure. the system does not use motors or electronics of any type inside the body. all electronics are in a pneumatic driver, which powers the artificial heart and monitors the patient’s blood flow.

implanted inside of a patient,” says Tom Carlson, manager of Bimba Manufacturing’s Service Excellence team. “Basically with a patient who has biventricular heart failure, the bottom half of their heart is cut

out and is replaced with essentially today’s version of the Jarvik heart.” Carlson says that two rubber diaphragms are “wetted components” provided as a part of the SynCardia package. These dia-

“We worked very closely with SynCardia to try to perfect what I call the rhythm of the heartbeat,” says Carlson. “Their goal is to have this product give a heart patient quality of life, not just provide a bridge to a transplantation." So they have a challenge of a 100 million cycles for the actuator, because 100 million cycles is approximately the number the typical human heart beats in one year. The Freedom driver is serviced by replacement every 120 days.

How do you make a high quality switch? By switching to Thomas Products, that’s how. Quality Level and Flow Switches... When you buy our products, you receive total quality assurance since we are a full-service operation from raw material purchase to design to product completion.

Model 4000

With more than three decades of business experience, we have established long-term working relationships with clients in diverse industries including: aerospace, automotive, mining, construction, petrochemical, medical, food, and beverage.

Model 1800

Model 4400

Model 1100

Model 5100 designers & manufacturers of quality level & flow sensors DN 10/11

860.621.9101 800.666.9101

ThomasProd.com

Supplament Name Here the concept For syncardia is to provide a Bridge to LiFe. To replicate the rhythm of the heartbeat, SynCardia has developed specific requirements in terms of output pressures that ultimately relate to the performance of the actuator. Consistency of the cylinder’s performance is a major reason why the SynCardia Freedom driver system works. “Bimba’s solution lies with the ability to maintain consistent output pressures, but our product itself is only one part of the entire system that SynCardia uses to make the Freedom driver,” says Carlson. “Software, monitors, and simple position sensing on the cylinders all provide an ability to monitor the performance of the Freedom driver. Pressure sensors are also used to be able to identify what is going on, and how the actuators are actually performing.”

[ w w w. des ig n n e w s . c o m ]

These challenges are not like a typical pneumatic system where you have ready access to be able to do maintenance or provide lubrication. Basically everything is built and has to be truly available, ready, and usable from the factory for long life. “The SynCardia Total Artificial Heart is what is implanted in the patient,” says Carlson. “The actuator is part of the Freedom driver, the component that the person is basically going to have to carry around with them, and makes being lightweight important. Providing a lightweight actuator that offers consistent actuation to replicate a heartbeat with a long life were the challenges we faced.” SynCardia says the Total Artificial Heart is the only device that pumps up to 9.5ℓ/ minute through both ventricles, and offers a physiologically responsive design where blood flow is based on activity level. The uniqueness of its partial fill/full eject design is that it accepts blood based on the needs of the patient’s body at rest. The two artificial ventricles partially fill and then fully eject the amount of blood returned to the heart by the body.

During exercise, increased muscle and body movement causes more blood to enter the ventricles. The ventricles can fill with up to 30 percent more blood but there is no need to adjust the heart rate because the body determines the amount of blood the artificial heart pumps. Inside each ventricle is the diaphragm that is responsible for pumping blood. Vacuum supplied by the pneumatic driver pulls the diaphragm down to allow blood to enter the ventricle. To eject blood, a precisely calibrated pulse of air then pushes the diaphragm to the top of the ventricle. Bridge to LiFe

Carlson says that every year there are approximately 100,000 people who could benefit from a heart transplant, but only about 2,000 hearts are donated annually. That leaves a wide gap that is never going to change and is only going to grow as the baby boomer generation gets older. The concept for SynCardia is to provide a bridge to life. The SynCardia Freedom driver system allows a patient to continue to live and regain their health while they

j an uary 2012 f luid p o we r / p o we r t r ans mis s io n / a s up p le me nt to de s ign n e ws F3

Fluid Power/Power Transmission are waiting for a donor heart. By understanding that the donation gap is always going to be there, the longer term goal of the project is that it allows the potential for a patient to not only check out of the hospital, but then enjoy a long-term, improved quality of life. It can conceivably keep them alive indefinitely while they are waiting for a new heart. The Freedom driver has approvals in Europe and has been used in dozens of patients worldwide. In 2010, a CBS news story showed the first patient walking out of a hospital using the Freedom driver after being hospitalized for two years. He was able to walk out of the hospital without a human heart, instead, using an artificial heart to walk around and sleep in his own bed for the first time. Over 25 years of use, the valves in the SynCardia Total Artificial Heart have never failed. The diaphragm has a failure rate of less than 1 percent over more than 950 implants (1,900-plus diaphragms). In working on the project, the SynCardia and Bimba engineering groups collaborated to develop advances to the

driver technology. “We have a great partnership with SynCardia, and our chief engineer is basically an extension of their engineering staff,” says Carlson. “What we learned is that they are medical people and that is their forte but, when you get into issues that are more fluid power related, they relied on us as a resource to help them develop the system.” In addition to fine-tuning the final design and dialing in the functionality of the actuators, Bimba was also a consultative resource for the overall system, and provided recommendations on how things work within the entire Freedom driver concept. Carlson says the collaboration has actually been very fruitful and Bimba is extremely proud to be part of this because it is a life-saving project. “When you see someone walk out of a hospital without a human heart and know that we have been part of helping to keep that person alive, that is a huge uplifting thing for our entire company,” Carlson says. To achieve high reliability, the key is

tried-and-true cylinder manufacturing and a combination of lubrication, seal materials, seal geometry, and selection of other bearing materials. “As with any specialty actuator design, the seals, pistons, bearings, and lubrication all play a role in its dynamic functionality, so we make sure that the selections provide optimal performance. From a pneumatic standpoint, the goal is not just about optimal life, but also to provide leak-free operation as well,” Carlson says. Bimba used a combination of empirical testing combined with experience, as well as modeling and simulation, to assist in developing its part of the Freedom driver technology. Carlson says that modeling can only take the process so far, but then the proof is in actually trying it out. FMEA analysis can take you so far, but it doesn’t replicate the nuance of an application, so performance validation in the application itself is a must. For more information, go to www.syncardia.com and www.bimba.com.

® PENINSULAR C Y L I N D E R C O.

PENINSULAR’S PROVEN CYLINDER FEATURES KEEP YOUR PLANT UP & RUNNING !

27650 Groesbeck Highway Roseville, Mi 48066-2759 Phone: 586-775-7211 Fax: 586-775-4545 F4 f lui d po wer/ power t r a n s m i s s i o n / a s u p p l e m e n t t o de s ign ne ws ja n u a ry 2012

[ www.designnews.com ]

Fluid Power/Power Transmission

Long-Travel Piezomotors:

new Innovations, new Solutions Piezo actuation is becoming increasingly suitable for applications formerly addressed by magnetic motors. By scott JordaN & steFaN vorNdraN, Pi (Physik iNstrumeNte) l.P.

P

iezoelectric actuation is the • Applications ranging from cell foundation for a myriad phone cameras to endoscopy and of mission-critical highfluid delivery require exceedingly technology applications, small but stiff, responsive, and relifrom semiconductor manufacturable positioning of optics, probes, ing to atomic-force microscopy, shutters, and other small loads. from optical tweezers to sub-pixel Fortunately, a confluence of new imaging, from battlefield targeting piezo-based approaches has breathed to genomic sequencing and medinew capability into the nano- and cal devices. Known for nanometer micro-positioning world. Some of precisions, piezoelectric principles these represent significant incremental are proving highly adaptable to advancement of essentially traditional new configurations and modalities. mechanisms; others represent signifiRecently developed mechanisms cant forks in the road of positioning built on a variety of novel applitechnology. cations of piezoelectric technology have burst through the former travel NaNometer PrecisioN — over millimeters: loNg limitations familiar from classical travel Flexures nanopositioning mechanisms. But Piezo Flexure actuators provide travel ranges from When precision is needed, piezoeleclike those time-tested mechanisms, 0.1mm to 2mm with high force and speed. they tric actuation is the default choice. those built on these newer principles are optimized for microfluidics and nanodosing in offer high axial force, exceptional biotechnology or medical design, and are available Similarly, when high force or high speeds, compactness, fieldlessness, for fast auto-focus applications. the sketch shows a dynamics is required, piezoelectric and stable position-hold without small low-cost flexure actuator and the basic design actuation represents the gold-standard. Piezo actuators have long been dither. These long-travel piezomo- of a precision micro-valve. used in semiconductor manufacturtors offer valuable, proven solutions ing and testing applications for their for engineers grappling with tough ments have, until recently, had no soluextreme speed and precision. Lately, technical and economic needs. tion. Application examples abound: In a variety of fields, applications are • Optic assemblies of escalating microscope manufacturers and medical placing conflicting demands on struc- sophistication require multiple axes device manufacturers have also warmed up tural and motion subassemblies. In- of nano-precision alignment yet must to the benefits of this actuator technology creasingly, positions must be controlled remain aligned for months of around- that has even been embraced by the automotive industry. in more degrees of freedom with higher the-clock usage. Traditionally, piezo stack actuators dynamic and static accuracy, yet faster • Emerging nanoimprint lithogthroughputs and longer travels are nec- raphies demand exquisite positioning offer limited maximum travel, on the essary to meet financial metrics. Com- and trajectory control yet must retain order of 0.1 percent of the stack’s length. pactness is prized, yet high speeds are alignment integrity under significant Helpfully effective flexure lever-amplification approaches have been devised over demanded. These conflicting require- physical and thermal stresses.

[ w w w. des ig n n e w s . c o m ]

J an uary 2012 f luid p o we r / p o we r tr ans mis s io n / a s up p le me nt to de s ign n e ws F5

Fluid Power/Power Transmission

Vibrational behavior of a piezo ceramic slab in a miniature ultrasonic motor (measured with 3D scanning laser vibrometer).

many years which today provide travels up to 2mm. The downside is that the stiffness of lever mechanisms diminishes as the square of the lever ratio. This limits the bandwidth and thus the tracking performance of traditional servo-control techniques. So, demands for longer travels plus faster actuation or higher holding force are at cross-purposes. Furthermore, at some point the granularity of the driving DAC will begin to be seen, limiting coarse positioning resolution or introducing bit-transition noise in position waveforms. This is now addressable by novel controls technologies. Digital Dynamic Linearization, a non-traditional algorithm integrated into the latest digital nanopositioning controls, virtually eliminates following errors in repetitive motion patterns and scanning of these long-travel nanomechanisms. The controller integrates the algorithm into the metrology and servo logic; this optimizes the internal command generated for a repetitive waveform according to

Aurora-Where_the_Action_Is:Aurora 11/5/10 1:10 PM Page 1

Rod Ends and Spherical Bearings designed and manufactured to Aurora's exacting standards for quality and durability. Registered and Certified to ISO-9001 and AS9100. From economy commercial to aerospace approved, we've got it all !

Aurora Bearing Company 901 Aucutt Road Montgomery IL. 60538 Complete library of CAD drawings and 3D models available at:

w w w . a u r o r a b e a r i n g . c o m

F6 f lui d po wer/ power t r a n s m i s s i o n / a s u p p l e m e n t t o de s ign ne ws Ja n u a ry 2012

[ www.designnews.com ]

WE’LL WE’LL Do Do ThE ThE

LIFTING LIFTING & & LoWERING LoWERING

the error signal detected with the internal sensor. A brief (typically