Full text of ' The print forum for the Microcomputer professional and semi-professional JOURNAL Septembeir/October 1994 “ # « * « # « * * * * * * 1 14138 95 GREG SELF on £ B Rancr 0FT p 0 BOX 2 74 Uwp-ms! **3-DIGIT 484 >02 9405N AOH ROAD,^, 8 ^ 14-0274 1* 1 1 1 f 1 I L >I fill I ( 1 1 1! ( Affordable Drives Let You Roll Your Own CD-ROMs Using A Serial Port For Discrete I/O Operations Applying PIC16C71 And PIC16C84 Microcontrollers Setting Up A BBS mputer 68HC11 Controller & Languages Program it in C or Basic or >rcim it in FORTH or Program it in Assembly Low Cost Development Package: Controller + Languages + Manuals on disk included! P ackage Price Breakthrough!

The NMIT-0020 Single Board Computer is perfect for dedicated controller with convenient interfaces for LCD displays and keypad. Intelligent LCD’s up to 2 lines by 80 characters and matrix keypads up to 4x5 can be used. The processor is the popular F68HC11 with many features, including SCI and SPI serial channels, 8-bit 8-ch. A/D, 20 available I/O lines, Watch Dog Timer, 1/2K EEPROM and Max-FORTH w/Floating Point Package embedded in 12K internal ROM. SBC expands F68HC 1 1 providing 3 28-pin JEDEC sockets for 8-32K RAMs, ROMs, EPROMs, EEPROMs, etc.

Dec 14, 2011. It is a GrandCare System, a product of a company in West Bend, Wis., that is being marketed locally for the first time by Cybermation, a Waite Park-based. Gladys Ardolf lived in Maple Lake and was 78 when she died of complications from dystonia, a movement disorder that causes muscles to contract and.

RS-232 conversion supplied. Requires external regulated supply: 5V at ~30 mA.

Based on NMIX- 0020 board, so many features may be added as desired by the user (or by factory - call for details & prices). Languages supplied on accessory disk: Small C, Basic, and Assembler. FORTH resident on chip (may be disabled). Languages come with manuals on disk. Communications utility, MAXTALK included to allow PC clone to act as terminal for download and development.

WIPE utility included allows internal ROM, EEPROM, WDT to be enabled/disabled, and EEPROM to be erased. Manuals on disk: UM-MAX Max-FORTH Users Manual, HM-20 NM1X-0020 Hardware Manual, Small C manuals with examples, BASIC!

SBC and utility disk - $99. Keypad and LCD not included.

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'PLUG AND PLAY' VIDEO MONITORS. The VESA Monitor Committee voted to release for for- mal approval a proposal that uses ACCESS bus as the control bus for the Display Data Channel (DDC) of computer monitors, allowing them to achieve full 'Plug and Play' status. With DDC, video monitors will automatically notify the host computer on power-up of their specific capabilities and configuration, automatically calling up the appropriate software driver.

Furthermore, DDC allows connecting ACCESS-bus peripheral devices— such as mice, modems and printers— direct ly to the monitor instead of hooking up each device separately at the rear of the computer. COLOR — PRINTER SALES BOOM. Ink-jet is the fastest -growing color printing technology on the U.S. Market today, with more than 1.5-million installed printers reported in operation in 1993. Since 1989, color ink-jet printer sales have grown more than 70% annually, with a projected installed 1997 base expected to be more than 13-million color ink-jet printers.

In comparison, there are only about 30,000 color laser printers now in operation in the U.S., while thermal wax-transfer color printers are estimated at only 130,000 units. RADiQ SHACK ADDS IBM BRAND. Radio Shack selected IBM as the first vendor in its pol- icy to sell name-brand computers in addition to its line of PC-compatible Tandy com- puters. The pilot program will start with about 500 Radio Shack stores among its 6,500 selling IBM's PS/Note Model E35 monochrome notebook and PS/Note Model C45 color notebook computers. Both are based on the Intel 486SL/25-MHz processor.

SCANNER TEST T ARGET. A new resolution test target that calibrates image scanners has been introduced by A&P International. The PM-189 Scanner Test Target, measuring 8-1/2' x 11', is a monochromatic photographic product that comes with 26 different test-pattern areas.

These include horizontal and vertical, 360-degree range, half- tone and micro-copy resolution, reference B/W, type and handwriting, edge markets, mechanical drive uniformity, linearity square, single-line thickness, line-thickness references, TV/Camera/Monitor resolution. It's priced at $125, with an optional 37-step grayscale available for $25 more. For more details, call Paul Montgomery at 612-738-9329. IBM announced a new digital 16-bit signal processor (DSP) for its MWave family of products. It's said to be the first processor to integrate Wave Table and Sound Blaster support. On-chip features include a full suite of multimedia inter- faces, high-speed analog and digital communication functions, a 32-voice wave-table synthesizer, extended audio and voice CODEC (coder-decoder) support and hardware- level support for industry- standard games. Hall Technologies and Interactive Products have joined forces to create a very inexpensive command -and -control voice-recognition system-on-a-chip.

Based on the pioneering work of a group of Russian software experts, the heart of the system is a version of IPI's software engine used in its current 'VoiceMouse' software for Windows 3.1. It's said to have an average accuracy of 98% while ignoring background noises. The system reportedly requires only a one-pass voice read to understand a user. The basic engine requires only 12K of program memory. It has a typical soft- ware vocabulary of 100 command-and-control functions for a consumer product, requir- ing merely 50K of additional memory. Thus, the entire engine and vocabulary can be embedded on a small chip.

The 'ChipTalk' chipset will use John Hall's refractory gate merged-emitter chip design, which is said to run five times faster than conven- tional CMOS circuitry. The system is designed to be used for a variety of voice- recognition purposes in home appliances and everyday consumer electronics.

Datalight ' s ROM-DOS 6.2 has been released, which is an MS-DOS 6. 2 -equivalent oper- ating system for Original Equipment Manufacturers of personal digital assistants and other types of embedded computers.

Datalight has signed an agreement with Stac Electronics to sell Stacker 3.0 along with ROM-DOS. ROM-DOS is claimed to be the smallest of any compatible DOS on the market at about half the size of MS-DOS 6.x in ROM.

6 / MICROCOMPUTER JOURNAL September/October 1994 The first alarm system designed to protect you as well as your car... Revolutionary new vehicle security system is the first of its kind to focus on the safety of the vehicle driver as well as the vehicle itself. By Charles Anton D o you wonder why car alarms have countless features to protect your car, but nothing to protect you? After all, what's more important your car or the safety of you and your family? Now there is a car alarm that will protect you and your family.

It is the first of its kind to focus on the safety of the ve- hicle owner as well as the vehicle itself. Protect yourself. It all begins with the panic button. Imagine you're walking to your car at night and a person ap- proaches. Pushing the panic button on your transmitter lets your car come alive with a shrieking siren and flashing headlights. While the panic alarms of other vehicle security systems have a range of 100 feet, the Smart Alarm's panic alarm lets you call for help or scare away potential attackers from up to 400 feet!

Exclusive feature. Unlike other car alarm systems that begin and end their focus on per- sonal protection with the panic alarm, that's just the beginning of the Smart Alarm.

In addition to the panic alarm, the Smart Alarm also has a car finder feature. You'll never again have to wander around a dark and dangerous parking lot searching for your car.

You will be able to know where your car is from anywhere within 400 feet by flashing its lights and briefly sound- ing the siren. You can activate and deactivate your car's headlights by remote control to light your way in a dark driveway or parking lot.

The Smart Alarm also ad- dresses a growing haz- ard for today's mo- torists — carjacking. It's alarming how often drivers are hurt in their cars because they re- fuse to give them up to carjackers. Because of its anti-carjacking de- vice. The Smart Alarm allows you to safely re- tain your car when con- fronted by a carjacker. This is made possible by a delayed panic alarm. What makes Smart Alarm better? Most car alarm features only work up to 100 feet away — all Smart Alarm features work up to 400 feet away.

■ Panic button. Smart Alarm lets you call for help or scare away potential trou- blemakers by controlling a piercing alarm and your car’s headlights.

■ Car finder. Your car will be able to let you know where it is by flashing it’s lights and briefly sounding the siren. ■ Carjacking. Its delayed panic alarm allows you to safely prevent theft of your car when confronted by a carjacker.

■ Easy installation. Other car alarms are complicated or cost hundreds of dol- lars to install. Smart Alarm is inexpen- sive, and you can install it in just minutes. Smart Alarm Is the first car alarm that will protect you and your family. Easy installation. Installing the Smart Alarm requires no fumbling with wires. Special Plug-ln Connectors let you install the Smart Alarm with- out a single wire-cutter!

Simply unplug the head- light connector, plug in the Smart Alarm connector, and then plug the headlight connector to the Smart Alarm. Connect the Smart Alarm to the battery cable zoith the special clip. In minutes, you and your car can enjoy complete 24-hour pro- tection. Away from your car, you'll feel safer know- ing that your car is protected!

Near your car, you'll feel safer knowing that you are protected! All you do is give up your car and activate the delayed panic alarm. When the assailant has reached a safe distance and is no longer a threat to you, a deafening 120dB siren and flashing lights will force him to flee your car, letting you recover it safely. Vehicle protection. Smart Alarm's cur- rent sensor triggers the siren if the trunk or any of the doors are opened while the alarm is armed. To supple- ment the current sensor, a shock sensor triggers the siren when it de- tects a blow to your car.

Together, these sensors provide your car with blan- ket protection. An adjustable shock sensor pre- vents the siren from being trig- gered, eliminating false alarms. You can also adjust the shock sensor and the siren with your remote control at any time you choose. The siren's tone and volume can be ad- justed to six separate tones. As a result, you'll never confuse it with any other alarm.

You can also customize the siren, making it louder in noisy neighborhoods and quieter in more peaceful neighborhoods. Risk-free home trial. With the Smart Alarm, you get a complete 'No Questions Asked' 30-day money-back guarantee. If it's not everything we say, just return it for a full refund. The Smart Alarm is also backed by a two-year warranty. Your order will be shipped UPS in seven to ten working days. The Smart Alarm Car Alarm $99 $9 S&H Compare Other car Smart alarms Alarm ■ • • 3S^ 1 00 feet Range.

Other ml car alarms only uwrk up to 100 B If feet. All Smart ‘..,. 400 feet Alarm features work up to 400 feet away. Please mention promotional code 483-CC1 1 05. For fastest service call toll-free 24 hours a day 800 - 992-2966 To order by mail, send check or money order for the total amount including S&H (VA residents add 4.5% sales tax.) Or charge it to your credit card, enclosing your account number and expiration date. INDUSTRIES 2820 Waterford Lake Drive Suite 106 Midlothian, Virginia 23113 Corrections During editing of Tom Benford’s “Beyond Double Speed and Single Discs: Pioneer Breaks the CD-ROM Bottleneck” beginning on page 79 of the July/August issue, an editorial error was introduced into the first sentence of the second paragraph. The sentence should read: “This article gives you an in-depth look at Pioneer’s DRM-604X mini-changer drive and compares it to NEC’s 84 drive [not the triple-speed NEC MultiSpin 3x series as printed] to provide you with a perspective on what you can expect from the DRM-604’s state-of-the-art features and performance.” Our apologies to Tom and NEC for this editorial error.

The photo shown for Blue Earth’s Xplor-32 Digital section of the July/August issue is incorrect. The Control Board on page 13 of the What’s New! Correct photo for this product is shown here.

Full text of ' Innovation in Locomotion THE DISSECTIBLE ROBOT SYSTEM At last..a robotics kit that students can assemble in a variety of configurations. Piece-by-piece, robotics training comes togeth- er with Lab-Volt's latest addition to its high-tech robotics program. Hands-on training in stepper motor control, linear and geometric motion con- trol, turret assembly, even gripper capabilities. Stu- dents build a fully functioning, fully programmable robot in just 30 minutes while building career skills that last a lifetime. Contact us We're P.O. Box 686 Farmingdale, N.J. 07727 (201) 938-2000 Outside N.J.

800-223-1057 Practical Career Skills Require Hands-On, Step-By-Step Training Programs Circle 4 Publisher/ Editorial Director Carl T. Editor Raymond GA Cote Consulting Editor Russ Adams Editorial Assistant Stephanie vL Henkel Production/Design Director Nancy Estle Assistant Production Manager Tobee Phipps Circulation Manager James E. Bingham Dealer Accounts Meredith Makela Typography Maryellen Kelly Receptionist Vi Depres Advertising Manager Donria Louzier Advertising Coordinator Cheryl Wilder Advertising Sales Jerry Merrifield Robotics Age Inc. 174 Concord Street Peterborough, NH 03458 603-924-7136 Member of Business Publications Audit THE JOURNAL OF INTELLIGENT MACHINES ROBOTICS JANUARY 1985 VOL. I EDITORIAL 2 The Turn of A Year by Carl Helmers FEATURES 7 The Walking Gyro by John W. Jameson A walking machine powered by gyroscopic precession. 1 1 Nomad Mk III The Flight of Fancy Conquer the air with an intelligent dirigible.

DeWitt 20 Robotix by Mark J. Robillard Part II: External Control Providing computer control for the basic building kit. 22 A Lisp -Based Robot by Doug Snead and Control System John Roach Part III: An Example Environment Using the robot controller as a laboratory partner.

ROBOTICS AGE— (ISSN 0197-1905) is published monthly by Robotics Age Inc., Strand Building, 174 Concord Street, Peter- borough, NH 03458, phone (603) 924-7136. Address subscrip- tions, changes of address, USPC Form 3579, and fulfillment questions to Robotics Age Subscriptions, 174 Concord Street, Peterborough, NH 03458. Second class postage paid at Peter- borough, NH and at additional mailing offices. POSTMASTER: Send address changes to ROBOTICS AGE, 174 Concord St., Peterborough, NH 03458. Subscriptions are $24 for one year (12 issues), $45 for two years (24 issues), $63 for three years (36 issues) in the USA and its possessions.

In Canada and Mexico, subscriptions are $28 for one year, $53 for two years, $75 for three years. For other countries, subscriptions are $32 for one year, surface delivery.

Air delivery to selected areas at additional charges, rates upon request. Single copy price is $3 in the U.S., $3.50 in Canada and Mexico, $4 in Europe, and $4.50 elsewhere. Foreign subscriptions and single copy sales should be remitted in United States funds drawn on a U.S. Address all editorial correspondence to the Editor at Robotics Age, Strand Building, 174 Concord Street, Peterborough, NH 03458. Opinions expressed by the authors of articles are not necessarily those of Robotics Age.

Tb aid in preparation of ac- ceptable articles, an Authors' Guide is available upon request, if accompanied by a self-addressed 8V2 by 11 inch envelope with first class postage for 3 ounces. Unacceptable manuscripts will be returned if accompanied by a self-addressed envelope with sufficient first class postage. Not responsible for lost manuscripts or photos. Each separate contribution to this issue, and the issue as a collective work, is © 1984 Robotics Age Inc. All rights reserved.

Copying done for other than personal or internal reference use without the permission of Robotics Age Inc. Is prohibited.

Re- quests for permission should be addressed in writing to Robotics Age Permissions, Strand Building, 174 Concord Street, Peter- borough, NH 03458. 26 Rethinking Robot Mobility by John M. Holland Designing a synchronized, omnidirectional robot base.

31 A Pneumatic Walking Robot by D. Todd, M.A., Ph.D. Walking machines can be constructed from readily-available materials without the necessity of a machine shop. DEPARTMENTS 3 Calendar 5 Sensory Perceptions 27 Advertiser Index 36 New Products Cov. Ill Classified Advertising About the cover: Robots are moving from the experimental lab out into the real world. New forms of robot locomotion are required to handle mobility and balance problems. This month's cover features the Synchro-drive base robot operating on a country road.

Photo courtesy Cybermation, Inc. ROBOTICS AGE January 1985 1 Circle 9 The DENNING RESEARCH VEHICLE Editorial The Turn of A Year Autonomous, Intelligent and Affordable. BY CARL HELMERS, PUBLISHER/EDITORIAL DIRECTOR Designed expressly for laboratory research in robotics and robotic programming (including artificial intelligence projects), Denning Mobile Robotics Model T gives you the capability and flexibility you’ve been looking for at a price you can afford. The Model T has a large and strong chassis and drive system upon which can be mounted a meaningful payload for vision, sensor and/or software research. The vehicle is just small enough to pass through standard doors, yet large enough to provide a platform of 4 square feet for custom mounting of research equipment.

The Model T is round, with three-wheel drive/three- wheel steering to simplify turning comers, approaching and passing through doors, and handling obstacles. Make no mistake, the Denning unit’s versatility in research and teaching applications is impressive. Features include: • Synchronous three-wheel drive/ three-wheel steering • Z80 Motor Control • Z80 Ultrasonic Sensor Ring • Built-in Object Avoidance • Approach doors at any angle • M68000 with 1 28K RAM for processing • Extra card slots for research use • Two payload platforms for research material Call 617-935-4840 today for more information. DENNING MOBILE ROBOTICS 21 Cummings Park, Woburn, MA 01801 PERSONAL ROBOTICS EXCLUSIVELY FACTORY AUTHORIZED DEALERS SENSATIONAL — CONTROL SYSTEM FOR HERO-1 Write, debug, edit, download programs from yourZ-100, H-89, Apple II, CoCo, PC, others MENOS System, includes RS232, 34K, OS in ROM from Virtual Devices, Inc. List $595.00 SALE $540.00 BURN YOUR OWN RB5X PROMS Introducing our Tiny BASIC PROM Development System Hardware, Software, Documentation — Complete Package for 8073 CPU VIC-20 Version $299.95 Commodore 64 Version $349.95 Dealer Inquiries Invited nna List SALE IzT.TTOH List SALE MOVIT ANDROBOT Screwdriver Kits— No Solder- -FUN Slave to your computer Avoider 44.95 40.15 TOPOII 15.00 Circular 67.95 63.75 Accessories CALL Line Tracer 39.95 36.75 COMRO Medusa 27.95 26.25 On-board 8-bit computer Memoconcrawler 74.95 70.15 TOT CALL Monkey 24.95 23.65 Accessories CALL Mr. Bootsman 30.95 29.25 HUBOT Peppy 24.95 23.65 On-board 8-bit computer Piper Mouse 44.95 40.13 Premier 1000 34.00 Sound Skipper 24.95 23.65 Accessories CALL Turn Backer 39.95 36.75 IOWA PRECISION HARVARD ASSOC.

On-board 16-bit computer Tasman Turtle 399.00 365.00 Marvin MKI 59.00 Turtle Tot 299.00 275.00 PERSONAL ROBOTICS CORP. ROBOT SHOP On-board 8-bit computer Droid Bug 129.95 122.00 Ropet-HR 24.00 Z-1 149.95 136.50 Ropet-XR 21.00 Z-2 249.95 223.50 Accessories CALL X-1 399.95 360.00 RB ROBOT RHINO Download from your computer Scorpion & XR-3 CALL RB5X 2295.00 Accessories 2058.00 CALL TECHNICAL INFO- -WE CAN HELP. CALL - conn A riA A 0 / Anri 1 Inrlor Arirt sji i ippn iy vyci nuu H Cash With Order Deduct 3%.

Allow 4 Wee /o. 5tUU Mnu unoBi muu d /o. Orders Add 4V«% Sales Tax. Iks For Delivery. ES RIO GRANDE ROBOTICS B£H 1595 W. Picacho #28, Las Cruces, N.M. (505) 524-9480 Once a year it happens.

The holiday season is upon us. January 1 comes and we see another turn of a year. A formerly current calendar becomes obsolete. This years turning is special. The human race survived the real 1984 without falling into a universal totalitarian abyss of an Orwellian prophecy. The world loves the demise of dire prophecies. Tn truth, technology has greatly improved our lives on this planet.

As engineers and experimenters, we are all part of this process of choosing new ways of achieving human ends in life. As 1985 begins, the pursuit of robotics technology is flourishing as we head toward the 21st century. As a publication devoted to the advanced applications of computer, electronic and mechanical technology, we are proud to be a part of the growth of the in- telligent machines technologies. The beginning of 1985 marks the start of Robotics Ages seventh year of publication.

1985 is also our second year of publica- tion as a monthly magazine. Well continue to do our best to present technical information for our technically oriented reader. The robotics engineering challenges remain. The pursuit of practical real- time computer systems continues to provide a fertile field for ingenuity. As always, market experimentation with products continues. At the IPRC in 1984, we saw a proposal for a semi-autonomous consumer lawn mower robot, powered by the usual gasoline engine. We’ve seen the coming and going of several attempts at commercial personal robotics products.

With this years holiday season, we’ve seen the beginnings of several consumer electronic robot toy concepts. Real- time computers continue to show up in places as diverse as kitchen appliances and automobiles— as well as in their “traditional” aerospace uses. The mobile platform robot is being marketed in several forms industrially and commercially. We’re also seeing serious proposals for military/industrial/ commercial-grade sentry and guard robots.

The defense establishment is even looking seriously at the concept of semi-autonomous land vehicles for hazar- dous duty assignments. Engineering any and all of these intelligent machine concepts requires cleverness and knowledge. What software development tools are appropriate for the engineering of such systems? What test and prototype systems are available to save on the time needed to get experimentation going?

Has anyone really figured out what the practical personal robot will do? What kinds of single board computers are available off the shelf for engineering of intelligent systems?

How do we control stepper motors and D.C. What kind of internal communications architectures are ap- propriate for multiple computer systems that run in real time? How do we hook up an I/O port to a single board LISP (or FORTH) computer? How will we pro- vide power for a semi-autonomous or autonomous mobile robot? Answers to these and many other questions of intelligent machine design are many— and subject to some debate. The personal robot is a test bed for ideas. Like the impractical early flying machines, our knowledge of what constitutes a personal robotic system is ex- panding.

The personal robot as a platform on which and thru which one does engineering experiments is a very viable commercial concept. It is not a toy. It is an aid to understanding the engineering of real systems working in real time.

The factories of the world cry out for automation engineering growth. Soft- ware as well as hardware must be developed.

There is a crucial need for an ar- tificial intelligence mode of thought on the part of systems designers and sup- pliers for the factory. When each application to the job shop is a special case, the number of human applications “experts” is in short supply. One cannot ex- pect the typical manufacturer to be both an expert on his own process and simultaneously an expert on innumerable robotics options as well. Commercial suppliers of robotic systems would do well to look at what minicomputer manufac- turers have done in terms of system configuration via an 'expert system' ap- proach to a similarly complex problem. Present automated computer configuration techniques in practical use save many man-hours of setup activity. Similar tech- niques should be provided by manufacturers of automated machine tools and robotic subsystems. The list of potentially practical intelligent machine applications and technologies is large.

Every new product chips away at the list by adding one more area to the list of things we humans know how to do. Every drop in the price of some vital component or technology adds to the list of potential applications. This is the vital progressive nature of our intelligent machine field as we pass another turn of a year. ■ [Editors note: Part II of A Third Generation Stepper Motor Controller by Ed Klingman and Karen Moty will appear next month.] 2 ROBOTICS AGE January 1985 Circle 23 Calendar February 1985 11 February. Artificial Intelligence and Expert Systems. Marriott/Copley, Boston, MA.

Contact: Lee Burgess, Rensselaer Polytechnic Institute, TVoy, NY 12181, telephone (518) 266-6589. This Executive Briefing session is designed by senior management for senior management personnel.

It will provide the basic information needed to make decisions about when and where to use AI/ES in your products and processes. 26-28 February. Agri-Mation 1. Palmer House Hotel, Chicago, IL. Contact: SME Public Rela- tions, One SME Drive, PO Box 930, Dearborn, MI 48121, telephone (313) 271-1500. The three-day exposition will feature demonstrations of a wide range of automated equipment used in the production of food, fiber, and biomass materials.

Featured will be new developments in irrigation and drainage, field equipment, material handling, storage and distribution, harvesting, processing, and the latest in computerized systems and services available to the agricultural manager, researcher, and engineer. Among the agricultural automa- tion products on display will be data acquisi- tion systems, measurement instruments, mobile robots, motors, programmable controllers, robotic components and systems, sensors, con- trols, transducers, and actuators. March 1985 4-6 March. San Antonio, TX. Con- tact: The Gunter Hotel, San Antonio, TX. Con- tact: The University of Texas, Health Science Center at San Antonio, Occupational Therapy Program, 7703 Floyd Curl Drive, San Antonio, TX, 78284, telephone (512) 691-7555.

FutureCare is a three-day conference concerning the role of technology in rehabilita- tion. The Symposium allows clinicians using the new technologies in rehabilitation to share their ideas, experiences, and research with others, while providing a forum for the exploration and discussion of a broad range of technological ap- plications to clinical rehabilitation. Topics in- clude cognitive rehabilitation, use of robot systems, patient evaluation and treatment, and computer-assisted instruction. Robotic End Effectors: Design and Applications Seminar. Holiday Inn Livonia- West, Livonia, MI. Contact: John McEachran, Special Programs Department, RI/SME, One SME Drive, PO Box 930, Dearborn, MI 48121, telephone (313) 271-1500, extension 382. This seminar will give comprehensive coverage to robotic end effector design tech- niques, sensors for tooling, compliant devices, interchangeable end-of-arm tooling devices, multihand tools, and magnets for tooling.

A number of case-study presentations will look at robotic end effectors for assembly, material handling, machine loading, metal cutting, and welding robotic systems. An added feature will be end effector vendor tabletop displays. Computers and Young Children. University of Delaware, Newark, DE. Fischer, Division of Continuing Education, University of Delaware, Newark, DE 19716, telephone (302) 451-8838.

This is the second national conference spon- sored by the University of Delaware. The con- ference explores the opportunities and prob- lems educators face as computers are intro- duced into educational programs. The emphasis is on programs for children 4-8 years old. Cobo Hall, Detroit, MI.

Contact: Jeff Burnstein, Robotic Industries limited time SPECIAL OFFER: SCORPION MOBILE ROBOT KIT World leaders in instructional robotics RHINO ROBOTS 3402 N. Box 4010 Champaign, IL 61820 (217)352-8485 Originally $660 NOW ONLY $299 SAVE OVER 50% FACTORY DIRECT ONLY The $299 package price gives you the Scorpion kit with everything needed for assembly plus our 250-page assembly and operation manual (a $20 value) as a free bonus. The Scorpion is a versatile floor mobile robot that can be run from the RS-232C port of any computer, small or large. It is designed specifically for the serious robotic enthusiast who owns a personal computer and would like to experiment with robotics, artificial intelli- gence, machine intelligence, pattern recognition, and mobile robot theory. These activities are permitted by the Scorpion by virtue of its unique features, which include 2 drive motors, 4 bumpers with 2 micro- switches each, 2 programmable eyes, a speaker with tone and dura- tion programmability, a 2 axis optical scanner tha allows patterns of the brightness of the robot’s environment to be displayed on the CRT of the computer, and a 2 phase floor scanner that can be used to allow the Scorpion to track the floor environment in an intelligent manner. Enclose check or money order with order. VISA and Mastercard charges accepted.

Circle 22 ROBOTICS AGE January 1985 3 Calendar Association, PO Box 1366, Dearborn, MI 48121, telephone (313) 271-7800. Vision ’85 will be the first major exhibition of machine vision systems and related equip- ment ever held. A comprehensive technical con- ference will accompany the show. Over 75 ex- hibitors are expected to demonstrate the latest in vision technology. The exposition will feature the latest in assembly, inspection, related vision components, computerization technologies, robotics, software, part identification, and sen- sors. Also featured will be parts assembly, material handling, work-in-progress, warehous- ing, guidance, and control technologies with vi- sion capabilities.

RIA’s sponsorship of Vision ’85 is an outgrowth of the trade association’s new emphasis on machine vision. A^rM 1985 8-2 April. SPIE’s Technical Symposium East ’85. Hyatt Regency Crystal City Hotel, Arl- ington, VA.

Contact: SPIE, PO Box 10, Bel- lingham, WA 98227, telephone (206) 676-3290. SPIE— The International Society for Optical Engineering— will conduct a symposium cover- ing topics ranging from photovoltaic technology to artificial intelligence applications.

Of par- ticular interest are the sessions titled “Applica- tions of Artificial Intelligence II” and “Sensor Design Using Computer Tools II.” The AI II ses- sion will discuss image understanding, expert systems, robot vision, computer vision, autono- mous navigation, autonomous vehicles, and contextual scene analysis. The Sensor Design II session will discuss the design of imaging and nonimaging sensors for all spectral regions, design of sensor subsystems and support sys- tems, and applications of personal computers to design, testing, and modeling.

17- 24 April. Hanover Fair.

Hanover, West Ger- many. Contact: Delia Associates, PO Box 338, Whitehouse, NJ 08888, telephone (201) 534-9044.

The 1985 Hanover Fair will place special em- phasis on mechanical and fluid power transmis- sion, controls, and industrial parts handling. A separate sector of the fair has been set up to accomodate pertinent exhibits. 18- 21 April. FutureWorld Expo. Moscone Center, San Francisco, CA. Contact: Future- World Expo, 940 Emmett Ave., Suite 14, Bel- mont, CA 94002, telephone (415) 595-2708. FutureWorld is a unique marketplace for presenting new ideas, new technologies, new products, and visions of our world to come.

Ex- hibited products include robots, computers, new automobile innovations, and the latest in fashion and home design. 22- 25 April. LASERBOTICS: Combining Laser and Robot Technologies. Ann Arbor, MI. Contact: Steve Palma, SME Special Programs Department, One SME Drive, PO Box 930, Dearborn, MI 48121, telephone (313) 271-1500. The program will feature speakers from the U.S., Europe, and Asia and will examine the latest advancements in the science of combin- ing lasers and robots to improve productivity. Co-chairperson Jack Lane, director of the Robotics Center at the GMI Engineering and Management Institute, and David Belforte, President, Belforte Associates, are preparing an agenda covering the latest advancements in laser tooling, robotic part presentation, laser- guided robotics, fiber optics, laser/robot welding and inspection.

23- 24 April. 1985 Conference on Intelligent Systems and Machines. Oakland University, Rochester, MI. Contact: Professor Nan K. Loh, Conference Chairman, Center for Robotics and Advanced Automation, School of Engineering and Computer Science, Oakland University, Rochester, MI 48063. Technical papers are requested which reflect both advances and applications in all aspects of intelligent systems and machines.

Suggested topics include: intelligent robots, machine in- telligence, adaptive control and estimation, visual perception, artificial intelligence for engineering design, intelligent simulation tools, computer-integrated manufacturing systems, knowledge representation, expert systems, game theory and military strategy, interpretation of multisensor information, and automatic pro- gramming. Authors are requested to submit a 300- to 500-word abstract by 1 December 1984. July 1985 15-19 July. Olympia 2, London, England.

Contact: Evan Steadman Services, Ltd., The Hub, Emson Close, Saffron Walden, Essex CB10 1HL, telephone 0799 26699. PC ’85 is Europe’s first exhibition and con- ference devoted entirely to programmable con- trollers and systems. The conference will focus on the rapid advances in the programmable controllers field, emphasizing the increasing power and capabilities of programmable con- trollers. Conference topics include program- mable controllers linked with personal com- puters, communication and distribution control, graphics, languages, and documentation. TOTAL CONTROL FORTH: FOR Z-80®, 8086, 68000, and IBM® PC Complies with the New 83-Standard GRAPHICS • GAMES* COMMUNICATIONS* ROBOTICS DATA ACQUISITION • PROCESS CONTROL • FORTH programs are instantly portable across the four most popular microprocessors.

• FORTH is interactive and conver- sational, but 20 times faster than BASIC. • FORTH programs are highly struc- tured, modular, easy to maintain. • FORTH affords direct control over all interrupts, memory locations, and i/o ports. • FORTH allows full access to DOS files and functions. • FORTH application programs can be compiled into turnkey COM files and distributed with no license fee. • FORTH Cross Compilers are available for ROM’ed or disk based ap- plications on most microprocessors. Trademarks: IBM.

International Business Machines Corp.; CP/M, Digital Research Inc.; PC/Forth + and PC/GEN, Laboratory Microsystems, Inc. FORTH Application Development Systems include interpreter /compiler with virtual memory management and multi-tasking, assembler, full screen editor, decompiler, utilities and 200 page manual. Standard random access files used for screen storage, extensions provided for access to all operating system functions. Z-80 FORTH for CP/M® 2.2 or MP/M II, $100.00; 8080 FORTH for CP/M 2.2 or MP/M II, $100.00; 8086 FORTH for CP/M-86 or MS-DOS, $100.00; PC/FORTH for PC-DOS. CP/M-86, or CCPM, $100.00; 68000 FORTH for CP/M-68K, $250.00. FORTH + Systems are 32 bit implementations that allow creation of programs as large as 1 megabyte.

The entire memory address space of the 68000 or 8086/88 is supported directly. PC FORTH + $2 FORTH + for CP/M-86 or MS-DOS $20 FORTH + for CP/M-68K $400.00 Extension Packages available include, soft- ware floating point, cross compilers, INTEL 8087 support, AMD 951 1 support, advanced col- or graphics, custom character sets, symbolic debugger, telecommunications, cross reference utility, B-tree file manager.

Write for brochure. Laboratory Microsystems Incorporated Post Office Box 10430, Marina del Rey, CA 90295 Phone credit card orders to (213) 306-7412 4 ROBOTICS AGE January 1985 Circle 14 Sensory Perceptions ROBOT TALLY. Census Department hopes to add a new question to their regular census questionnaires, “How many robots do you own?” The Census Department will include the results as part of the Current Industrial Report which tracks industry development. Although a primary concern will be the use and location of industrial robots throughout the na- tion, the U.S. Census Bureau recognizes the existence of inexpensive educational, ex- perimental, and personal robots. If the project receives the necessary authorization from the Office of Management and Budget, the Cen- sus Department will begin tallying domestical- ly produced robots in the calendar-year 1984.

The results will be used to assess the rapidly growing robotics industry and track rapidly developing technology. ENGELBERGER AWARDS. The 1984 Joseph F.

Engelberger Awards were presented at the 14th International Swedish TVade Fair Robots Show. The recepients were: James S.

Albus, chief of the National Bureau of Standards, In- BY RAYMO ND COTE dustrial Systems Division; Cesare Bracco, vice president and general director of manufactur- ing, Fiat Auto in Italy; and William R. Tanner, president, Productivity Systems, Inc. James Albus received the award for his work in technology development, in particular his hierarchical control system which, according to the NBS, is now widely used as a basis for the design of advanced robot control systems. Cesare Bracco received the award for his ap- plication of robots in the field of car body welding and mechanical assembly. William Tan- ner received his award for his work in the field of robotics education. Tanner has developed and conducted robotics seminars for more than 14 years.

ROBOT SAFETY. The National Bureau of Standards and Martin Marietta Corp. Have an- nounced a new joint research program to design a generic robot safety system that employs ar- tificial intelligence techniques. Carlos Ramirez, the principal investigator in robotics research and development for Martin Marietta of Michoud, Louisianna, will work with the NBS Center for Manufacturing Engineering on a preliminary study of the requirements for such a system, and on a basic design for the system configuration and interfaces to the robot con- troller and sensors. The Journal of Forth Applica- tion and Research, now starting its second year, provides a variety of Forth information for the serious Forth developer interested in real-time, hardware-intensive control situations. The first volume of the Journal which is devoted to Forth and Robotics is now available as a single copy for $15.

The papers presented in Volume 1, Number 1 include “Expert System for Diesel Electric Locomotive Repair” “A State Space Ap- proach to Robotics,” “Control of a Cartesian Robot,” and “Improvement of a Human/Robot Interface Through the Use of Forth.” The Jour- nal is available from The Institute for Applied Forth Research, Inc., PO Box 27686, Rochest- er, NY 14627. MODULAR, INDUSTRIAL ROBOTS TO GO! Our robots are ideal for corporate and academic R&D programs, clean room applications, and hazardous environments. Built for continuous duty in industrial environments, our mobile robots go the extra distance in other ways, too.

Our patented, omni- directional, polar-coordinate steering system is ideal for straightforward interface to computer control systems. YOU'LL LIKE THE WAY THEY MOVE. With a zero turning radius, our robot goes wherever you want on the job, even over 4” curbs, uneven surfaces and steep ramps. It can follow any path geometry without having to compute turning radii. By turning only the wheels and turret, the robot avoids wasting energy. We give you the freedom to elect how mobile!IIQ3F?mAeiOn 5457 JAE Valley Road, Jf Roanoke, Virginia 24014 * (703) 982-2641 you'd like your robot to be. It can be teleoperated, wire-following or fully independent.

Depending on stability requirements, the base is available with or without retractable legs that pivot to tuck underneath the housing. Although they can move through gravel, mud and grease, they're nondestructive to all floor surfaces. YOU'LL LIKE THE WAY THEY THINK. With its completely integrated computer and motor control package, our innovative modular robotics approach enables you to address a wealth of applications never before realized.

A variety of application turrets will be available. For more information on turnkey mobility in a robust, industrial robot, write Mike Frank, Cybermation, Inc., 5457 JAE Valley Road, Roanoke, Virginia 24014. Or call (703) 982-2641.

Circle 7 ROBOTICS AGE January 1985 5 Sensory Perceptions Forth, Inc. Is sending their polyForth II system into space. The McDonnell Douglas Astronautics Company selected polyForth II for its Electrophoresis Operations in Space (EOS) project, the first manufacturing plant in space. The EOS project uses a continuous-flow electro- phoresis device in the weightlessness of space to separate biological materials— such as cells, enzymes, hormones— from mixtures for later use as pharmaceutical products. The EOS device will be mounted in the Space Shuttle payload bay. The unit includes eight microprocessors responsible for the autono- mous control of the electrophoresis process. The EOS can separate over 700 times more material and can achieve purity levels more than four times greater than those possible in similar operations on Earth.

ORANGE PICKERS. Odetics, Inc. Has received a research contract from the United States Department of Agriculture to perform a six- month study and produce a detailed design specification for an ‘Automated Citrus Fruit Harvester.” The University of Florida at Gainesville, an expert in agricultural applica- tions of technology, is being retained as a sub- contractor by Odetics. The company expects this Phase I agreement to lead to a second con- tract to actually develop and demonstrate a mobile robot capable of automatically harvest- ing an orange crop. PLOTTING MOUSE. American Micro Pro- ducts, Inc. (AM PI) has been demonstrating a German-built robot plotter.

The robot plotter is a small box with three pens that travels around a piece of paper taped to a smooth table. Although at first glance it sounds like the plot- ter couldn’t possibly have any chance of being accurate, a recent demonstration showed a sur- prising accuracy and repeatability. A ribbon cable connects the roving plotter to the robot control box. The control box can be connected to any computer with an RS-232 serial port. When initialized, the robot seeks out a corner of the paper and positions itself at a known position away from the corner. Sim- ple plotting commands can then send the plot- ter about the paper to produce plots with up to three colored pens. One of the built-in features is the robot plotters ability to know when its connecting ribbon cable is wound around itself.

It will then automatically unwind itself. Although the plotter does a fine job of drawing straight lines, it does an amazing job drawing circles. The plotter has to be seen to be believed as it decides to turn first one way then another while drawing an arc. A variety of built-in algorithms help determine the most efficient manner for drawing particular lines. The robot plotter also has a slot in its center for a felt-tip pen.

Placing a pen in this slot allows the plotter to act just like a Logo turtle. The robot plotter can also be placed in a particular mode for accepting turtle commands like FOR- WARD 10 and LEFT 90. For more information about the robot plot- ter, contact American Micro Products, Inc., 705 North Bowser, Richardson, TX 75081.

Where do you place your orders for a personal robot when you live in the middle of Mexico? Niki Delgado hopes you will order from Rio Grande Robotics of Las Cruces, New Mexico. The company has recently placed robot ads in several Spanish language engineering publications and has prepared Spanish language price lists and data sheets. Rio Grande Robotics is also considering translating manuals into Spanish. Further east, Hubotics, Inc. Of Carlsbad, California has announced a joint venture with Schilling Mess U. Regeltechnik in Frankfurt, Germany.

Schilling, a developer and distributor of automation and control systems, will in- troduce Hubot to the European audience at the Photo Kena Trade Show in Cologne, Germany. The Frankfurt company will then spend several months preparing the robot to meet VDE (U.S. FCC equivalent) specifications in Germany, Austria, and Switzerland. Schilling has already committed to the purchase of 500 robots by April 1985.

Sonar — Stepper Motor Controller — Digital Interface for your IBM® PC Hobbiests, Researchers, Educators— interface your IBM® PC to the real world. Robotics, process control and security applications are within your reach. • SONAR-I/O Board— SONAR ranging unit with transducer provides distance measurement up to 40 ft.— variable resolution down to.1 inches.

Echo mode selects single or multiple object returns for advanced SONAR imaging. 16 programmable TTL compatable I/O lines available. SONAR supported by user-callable assembly lan- guage drivers SIO 0102-1 $225.00 • Digital Interface Board— 24 lines of programmable digital I/O, TTL compatable, dual row header connection for user interface. Exam- ple program listings included. DIB 0101-1 $89.00 IBM is a trademark of International Business Machines Corp.

Money Orders Only Please • Stepper Motor Controller/Driver Boards— Drives 6 stepper motors at variable speeds using assembly language driver callable from BASIC. Half or full step modes user selectable.

External, buffered driver board (included) handles user's power supply of up to 25 volts @ 4 amps per phase of stepper motor. SMC 0103-1 $299.00 • SONAR/Stepper Motor Controller Board— Best features of all above— SONAR ranging and control of 4 stepper motors. Includes controller board, transducer, external driver board and software. SSC 0104-1 $399.00 For more information about these products, write: PRISM Robotics Inc., RO. Box 9474, Knoxville, TN 37920 (615) 573-4944 6 ROBOTICS AGE January 1985 Circle 20 THE WALKING GYRO John W. Jameson 275 E. O’Keefe #7 Palo Alto, CA 94303 Walking machines generally fall into one of two categories: statically balanced or dynamically balanced.

A statically balanced machine maintains stability at every posi- tion in its stride by always keeping its center of gravity above the region of con- tact between the machine and the surface. A dynamically balanced machine is gen- erally not statically stable at every stride position and must rely on intermittently ap- plied control forces in order to keep upright. The Walking Gyro seems to fit best into the latter category, but its simplicity relative to other forms of dynamically stabilized walking machines makes it an attractive alternative for home experimentation.

T vo characteristics are readily observed by experimentation with any toy gyroscope. One is the gyroscope's inherent stability, as illustrated by its ability to stay upright while keeping only one point in contact with a supporting surface. Another is the counter-intuitive reaction the device ex- hibits when the gyroscope is twisted about an axis perpendicular to the flywheel spin axis. The Walking Gyro utilizes both characteristics plus a third, gyroscopic precession, to provide a walking mobility base.

Although I have not yet constructed a model of the scale desirable for an ex- perimental home robot, my analysis of the Walking Gyro's dynamics indicates that such a device is feasible. In fact, the analysis indicates that the stability and load-carrying capabilities increase drama- tically with scale. Although the principles of the Walking Gyro are somewhat compli- cated, the basic mechanism is quite simple.

Adding velocity and direction control offers a challenging (though not necessarily com- plicated) task for the home experimenter. The Walking Gyro utilizes the angular momentum of a spinning flywheel to per- form the following functions: lift the feet, balance during the stride via gyroscopic reaction torque, and move forward via Photo 1. The Walking Gyro caught in mid-step. Gyroscopic precession.

My prototype, shown in Photo 1, is powered by a hand crank and relies on energy stored in the flywheel to sustain motion. Figure 1 shows a side view, partially sec- tioned, of a Walking Gyro in mid-stride. The housing (1), which contains the fly- wheel (2), and the gear train (3), is caused to tilt back and forth with respect to the leg frame (4) by the crank (5) and link (6). This motion is about the fore-and-aft pivot (7).

The legs (8) are attached to the leg frame by the fore-and-aft pivots (9) and the feet (10) are attached to the legs by the ver- tical pivots (11). Finally, the horizontal bar (12) connects to both legs by the fore-and- aft pivots (13) so that they stay parallel. Note that in this particular presentation, the mechanism is equipped with an adap- tor for a crank (14), which is used to bring the flywheel up to operating speed. SIMPLE EXPLANATION Figure 2 details the mechanism's movements. Figure 2a shows the Walking Gyroscope in a neutral position. Figures 2b and 2c show the motion that would oc- cur if the feet were somehow attached to the walking surface. Figure 2b shows the housing tilting to the left, and Figure 2c shows a tilt to the right.

Figures 2e and 2f show what happens if the same condi- tions of Figures 2b and 2c occur but with the feet free to move. Instead of the hbus- Figure 1. Cross-section of a slightly altered form of the prototype Walking Gyro.

ROBOTICS AGE January 1985 7 (d) (e) (f) Figure 2. Operation of the Walking Gyro. Figures 2a thru 2c assume the feet have been secured to the sur- face to demonstrate body motion.

The numbers in Figure 2a correspond to the part numbers in Figure 1. Ing tilting to the left, the gyroscopic ele- ment maintains the vertical attitude of the housing, and thus the left foot is lifted off the surface, conserving the housing tilt angle with respect to the leg frame (Figure 2e).

As soon as the left foot is off the sur- face, gyroscopic precession causes the housing to pivot about the right foot. The left foot returns to the surface as the crank goes around, whereupon the right foot is lifted in a similar fashion (Figure 20.

The housing then pivots about the left foot. Since the precession about opposite feet is in the opposite direction, the result is a forward walking motion. This explanation does not adequately ac- count for the Walking Gyros ability to pick up its feet. The primary aspects of the Walking Gyro’s operation are based on the well-established theory of gyroscopic motion. GYR OSCOPIC MOMENT Figure 3 shows a gyroscope supported at one end by a pedestal, which is analogous to the Walking Gyro taking a stride.

To understand how the gyroscope is able to support itself as it precesses about the pedestal, you need to understand what a moment is. A moment can be viewed as a system of forces acting on a rigid body that tends to turn the body about some axis. As an example, consider the moment 8 ROBOTICS AGE January 1985 y Figure 3. Forces acting on a gyroscope supported on a pedestal. M v about the y-axis due to the two forces Fj and F 2 as shown in Figure 3.

Fi and F 2 are equal in magnitude but act in opposite directions (and perpendicular to the y- axis), and di and d 2 are distances from the y-axis to F x and F 2, respectively. For this case, the moment M y is determined by the difference Fjdi-F^. Since Fj = F 2 (equals F), however, then M y = FAd, where Ad = di-d 2 is the distance between the lines of action of F] and F 2. Note that the resultant force due to Fj and F 2 for this case is Fj-F 2 = F- F=0.

Thus, such a force system, common- ly called a couple, is identical to a moment M y acting about a direction parallel to the y-axis. Note that the effect of a couple, or pure moment, is independent of where it is applied. A gyroscope’s ability to suspend itself with its center of gravity beyond the region of support, as suggested by Figure 3, is due to the so-called gyroscopic moment which can be designated as M y>g. This is a mo- ment produced about the y-axis by the spinning flywheel such that it exactly counteracts the moment due to the weight of the gyroscope (W) acting at its center of gravity at a distance / from the pedestal, that is, M yg =W/. This aspect of a gyroscope will be discussed further. PRECESSION RATE, STRIDE ARC, AND FORWAR D VELOCITY Three angular rates (Q, 0, and ly) are ascribed to the gyroscope’s x-, y-, and z-axes shown in Figure 3.

These three values cor- respond to spin rate, tilt rate, and preces- sion rate. For the configuration shown in Figure 3, the precession rate (in radians per se- cond) is: where: W= weight (lbs) of the Walking Gyro. / = horizontal distance (inches) from a leg to a line passing through the device’s center of gravity. A = moment of inertia (lb-in 2 ) of the flywheel about the spin axis.

Since ly is constant, the arc of the stride is: Astride == Astride (2) where t str j de is the elapsed time for the stride. If the gear ratio between the crank and the flywheel is N (for the prototype N = 50), then t str j de is equal to ttN/Q, and the arc of the stride is: TlW/N /Q v Astride — j Q2 W* Note that if Astride =360° the Walking Gyro will simply rotate in circles about two fixed points. The formula for the forward velocity (v) of the Walking Gyro is: Note that for equations 2 thru 4, it is assumed that no time is spent while both feet are on the surface. Thus, the actual Astride anr) H J wn = 0.5° = running angle for maximum loading The physical prototype properties are presented in Tctble 1, along with the estimated values of if>start and ip run. Thble 2 presents the diameter of the flywheel, for- ward velocity, and cargo capacity (weight) for the s-prototype for various values of s and flywheel speeds (Q). The values of if» start and iffrun, as well as the values in Thble 2, assume operation on a rough sur- face, where little or no slippage occurs.

Note that the case s = 1 and Q = 2300 rpm corresponds to the minimum flywheel TABLE 2 Properties of Scaled Versions of the Prototype s (scale) Q (rpm) D t (in) v (in/sec) W c (lb) 1.000 2300.0 3.000 3.782 0.00 1.667 2300.0 5.000 6.303 1.65 2.333 2300.0 7.000 8.824 9.08 3.000 2300.0 9.000 11.345 28.93 4.333 2300.0 13.000 16.388 145.33 1.000 4000.0 3.000 6.577 1.08 1.667 4000.0 5.000 10.962 10.02 2.333 4000.0 7.000 15.346 41.23 3.000 4000.0 9.000 19.731 116.80 4.333 4000.0 13.000 28.500 527.83 is scaled by a factor s, and that this ver- sion is called the scaled-prototype or s- prototype. Furthermore, assume that is constant, regardless of the scale (or value of s), and that yj^ = ip Rf corresponding to the maximum lifting capability. Based on these assumptions, I found that the cargo- carrying ability of the s-prototpye is approx- imated by the following expression: where: W c = cargo weight (lbs) for the s-prototype Wj = weigh t(lbs) of the original prototype (s=l) Q s =spin rate of the flywheel for the s-prototype Qi =spin rate of the flywheel for the original prototype Thus, the equation shows that the cargo weight is proportional to the fourth power of the scale and the square of the flywheel spin rate. It is interesting to note that equa- tion 5 is obtained whether i^ start or tf>run is used for comparison between the original prototype and the s-prototype. Finally, the corresponding precession rate of the s-prototype is: speed for which the original prototype can carry itself with no cargo weight. SUMMARY Clearly, the Walking Gyro is capable of car- rying substantial loads for larger sizes and higher flywheel speeds. Note, however, that these values are based on lifting angles that are probably larger than would be desired for a home robot.

In other words, by sacrificing some of the cargo weight (W c ) the stability of the Walking Gyro can be greatly enhanced. Now that you understand the operation of the Walking Gyro, can you figure out a good way to control it? AUTHORS NOTE The Walking Gyro is protected under U.S. 4,365,437, entitled “Gyroscopic Walk- ing Toy.” Reader Feedback To rate this article, circle the appropriate number on the Reader Service card. 70 80 90 Excellent Good Fair 10 ROBOTICS AGE January 1985 THE FLIGHT OF FANCY Brent G. DeWitt 4809 West Moorhead Circle Boulder, CO 80303 The idea of a floating robot was con- ceived on one of those typical stormy Col- orado winter evenings when there is nothing better than sitting around a fire and talking with friends.

On this occasion, Jon Marshall, a friend and fellow amateur inventor, and myself were watching an evening news report on the problems of taking gas samples in the Three Mile Island reactor building. It seems that a major part of the problem dealt with the number of vertical ladders in the structure. This prompted a long and varied discussion on methods of descending and ascending lad- ders. Methods ranged from ape-armed robots to “bat hooks” that were fired from a compressed air cannon and winched up or down. It quickly became obvious to us why, to date, there have been very few robots designed which can negotiate stair- ways, much less ladders.

In an archetypical case of Edward DeBono’s lateral thinking, it came to us that the problem was not one of going up and down ladders, but rather one of getting from the top of a ladder to the bottom, and back again. A flying robot was obviously an alter- native. Although an intelligent electric helicopter did cross our minds, the thought of debugging software for a machine with rapidly whirling blades quickly stilled our enthusiasm for such a project. In addition, the speed with which a helicopter must move was a problem; the faster the vehi- cle, the faster the digital control systems required to run it. The gentle elegance of a balloon held a strong aesthetic appeal for both of us.

Its slow movement would allow more reasonable processing speed, and even if it should run into someone head-on, no one (or thing) would be the worse for it. Such was the birth of an intelligent dirigi- ble which very shortly after was christened Nomad Mk II after the original Nomad of the Star Tirek television series. (The fiction- al Nomad was a floating robot, with anti- gravity drive and nearly infinite power.) While the idea was promising, it did not end the debate.

Could we really build an intelligent robot light enough to be sus- pended from a bag of helium and still able to pass through a normal door? At first neither of us were sure. Junkbox parts were piled on a scale and weighed.

A few “back of the envelope” calculations were made, and some totally unfounded guesses were added. It looked promising. Shear excite- ment for the concept was enough to carry it from there. This article is both a description of my efforts and, hopefully, a guide to the ex- perimenter wishing to explore these ideas on their own. PV = nRT AND THE' REALITIES OF AIR Unlike Nomad of Star TVek fame, Nomad Mk II was limited by the realities of the lift available from a balloon.

Air is not very heavy— about 1 kg/m 3. Even an ideal gas with no “weight” would still only be able to lift the weight of the air held in the same size bag. Since we wanted Nomad Mk II to be able to pass through a standard door, our dimensions were limited to approx- imately 65 cm wide by 1.2 m high, allow- ing for the undercarriage and some reasonable clearance for navigation inaccuracies. One of the simplest shapes for naviga- tion is a vertical cylinder (a rectangular solid would require the robot to know the relative angle between its corners and the doorway). The volume of a cylinder is equal to 3.1415xr 2 xh (r is the radius of the cyl- inder and h is the height).

This yields a volume of a little less than 0.4 m 3 for the door-limited dimensions. This is the best we can do. Unfortunately the air is a harsh mistress (apologies to R. The behavior of all gases (like air) follow a formula called the universal gas law (which is not nearly as ominous as it sounds). The universal gas law is stated as follows: PxV=nxRxT where: P= pressure above absolute vacuum V= volume of the gas n =the number of gram atomic volumes of the gas ROBOTICS AGE January 1985 1 1 R = the universal gas constant T = the temperature in degrees Kelvin Fortunately, we aren’t going to fool with those strange numbers of n and R. Instead, we will use the graph of helium lift vs.

Alti- tude in Figure 1. At sea level and 25°C, air weighs 1225 gm/m 3.

Under the same conditions, helium weighs 166 gm/m 3. The difference of 1059 gm is the lift under those standard conditions. Now for reality.

As you can see, the loss of lift at an altitude of 5300 ft. (1600 m) where I live, is significant; about 13 per- cent. The same kind of lift losses occur from temperature. The hotter the day, the less the lift. Pilots call the combination of these two factors the equivalent density altitude and it has direct influence on air craft performance. Because of the above equation, it is obvious that the decrease in temperature related density is propor- tional to the ratio of the temperatures in degrees Kelvin. How do you determine Kelvin degrees?

Actually it’s quite simple; just add 279 to the temperature in degrees Celsius (Centigrade). The following formula will assist those of you who do not yet have a Celsius thermometer: degrees Celsius = (degrees Fahrenheit - 32) x 5/9 For my maximum bag size, at 5300 ft., and 35°C, the answer is approximately 356 gm (or 12.5 oz) of lift. Now we know the lift we can expect from the gas.

With lift numbers this small, the weight of everything matters. I spent an evening weighing everything that might be useful in building Nomad Mk II. For reference, I have included most of the weights in T^ble 1. The bag itself is a major concern. The surface area for the bag I described is 2.45 m?

Obviously a very thin material is called for. This is a problem since helium is a sneaky gas. It finds its way out of or through almost anything. If thin plastic is used, a significant portion of the helium will eventually leak through the bag.

While prowling through a local kite store, I found a simple “first try” in the form of the Solar UFO. This is a very thin black polyethylene bag, only 10 microns thick (a micron is a millionth of a meter). The bag is approximately two feet in diameter and ten feet long. Microsoft Train Simulator 2 Free Download Full Version.

It comes as a tube and the user ties the ends shut with nylon string. When filled with air and placed in the sun the Solar UFO heats up and causes the contained air to expand. As the air ex- pands, its density is lowered and the bag becomes a solar-powered free-flying balloon. This effect is so strong that the package warns not to release it for free flight since it might reach an altitude of 30,000 ft. And be a hazard to air naviga- tion. Now the bad news.

I used the Solar UFO bag with Nomad Mk II at the International Personal Robotics Conference in Albu- querque, New Mexico. The helium leak rate was very high. It seems the manufac- turing process for making the bags so thin TABLE 1 Part Weight 40-pin 1C (plastic) 5.8 gm 16 or 14-pin 1C (plastic) 1.1 gm 24-pin 1C (plastic) 3.5 gm 24-pin 1C (ceramic) 6.4 gm 28-pin 1C (ceramic) 8.4 gm 16-pin DIP relay 2.1 gm annunciator (piezo electric) 4.3 gm AA battery (1.5 V, 125 mAH) 23.2 gm Poloroid battery (lead/acid, 6 V) 27.4 gm “foam core” artists board (V5» in.) 0.45 gm/in?

“soft' balsa wood (Vi 6 in.) 0.2 gm/in? Nomad laminate 1.0 gm/in?

0.001 in mylar (clear) 0.02 gm/in? Silver MONOKOTE 0.052 gm/in? Translucent MICAFILM 0.032 gm/in? Clear MICAFILM 0.016 gm/in? “Solar UFO' plastic 0.006 gm/in? (approximately) Tbble 1.

Weights for various parts used for the Nomad Mk II and Mk III. Was not very well controlled. Some spots in the bag are stretched so thin that they are transparent [ed.note: Since the Solar UFO is simply a toy, consumers may be seeing the reject material from a precisely- defined manufacturing process. Therefore, the quality of individual bags may vary, rgac] My estimate of the loss rate is about 15 to 20 percent per hour. At the IPRC, I was able to fly Nomad Mk II for about 15 minutes before I had to add helium. Ac- tually, this was not a big problem since the battery life was only about 20 minutes with my original batteries. In contrast, the pro- totype bag for Nomad Mk III made from 1 mil silvered mylar showed less than 5 per- cent helium loss in one hour but at a cost of three times the weight.

There are several materials that promise to make a suitable air bag. Micafilm is a material made by Coverite that is made for covering the wings and flying surfaces of model aircraft. It is extremely strong, resists punctures, and does not propagate rips. Its thickness is sufficient that the leak rate should be reasonably low and its weight is almost half that of silvered mylar. In the cases where I have built bags from sheet stock, I have sealed the edges with two-inch wide, 1 mil mylar tape, similar to that sold for package sealing. Two more general concerns for those de- signing their own floating robot: accelera- tion and turning speed.

For example, the light-weight ESCAP motors used on the Nomad Mk II don’t push very hard. Figure 500 1000 1500 2000 2500 3000 3500 4000 ALTITUDE IN METERS Figure 1. Helium lift per cubic meter vs. 1 2 ROBOTICS AGE January 1985 MOTOR VOLTAGE IN VOLTS Figure 2. Motor thrust vs.

Voltage for ESCAP motor and 4.5x2 in. 2 shows the thrust vs. Voltage curve for these motors.

This motor is an ironless core motor commonly used in radio ser- vocontrols. The propeller is a common Cox 4.5 in. Diameter with a pitch of 2 in. Per revolution. (The pitch is the distance the propeller would move forward as an ideal screw for one revolution.) This propeller is actually too large for the motor, but smaller propellers are hard to find. Elec- tric motors are very sensitive to prop matching with respect to their efficiency. Overloading the motor with a propeller that is too large causes the motor to draw more current and reduces battery life while producing only slightly more thrust.

Although the robot is lightweight, it is still pretty massive compared to the avail- able thrust. This means it will change di- rection rather slowly.

For most cases, this is actually an advantage. Since things hap- pen slowly, the microprocessor has more time to calculate its next move.

Nomad Mk II took three to four seconds to com- plete a 180 degree turn. For rough estimates, the rotational moment of the bag is approximately the mass of the bag and the helium times% the diameter of the bag. For Nomad Mk III, the weight of the bag and helium is about 340 gm (for the silvered mylar bag). This means that the moment is 340 gm times 32 cm times% or 7000 gm-cm. The motor thrust graph shows that the available thrust is 2.2 gm at 12 V. Since the motor is mounted at the end of a 23 cm arm, it produces about 50 gm-cm of torque (force times the moment arm) for each of the two motors. This produces a rotational acceleration of 1/140 of a g (stan- dard acceleration of gravity or 32 ft.

Now for a bit of trickiness. To make a maximum rate 180 degree turn and be COMPUTER CONTROLLED ROBOTICS 1. DRIVER BOARD 5005 DB $75 * 4.5' X 3.8' xO.5', TTL/CMOS COMPATIBLE, OPTICALLY INSOLATED, FOR 4 PHASE MOTORS 2AMPS/50 VOLTS ZLINEAR ACTUATOR 601 AM $ 75 12V/12W, 16 OH,.OOl' STEP SIZE _ 19 LBS HOLDING FORCE. 3 IN TRAVEL 3. LINEAR ACTUATOR 501 AM $43 12V/3.5W, 1.5 OH,.002' STEP SIZE 40 OH HOLDING FORCE, 1.88 IN TRAVEL 4. STEPPER MOTOR 201 SM $ 16 5V/2W, 1.0 OH, 15° STEP SIZE 0.8 OH/IN HOLDING TORQUE 5.

STEPPER MOTOR 301 SM $ 59 12V, 21.5 OH, 1.8° STEP SIZE 80 OZ/IN HOLDING TORQUE 6. MOTOR MOUNT FOR 301 SM $25 aimmiiniv 7 MOTOR MOUNT FOR 501 AM $ 12 Circle 2 ROBOTICS AGE January 1985 1 3 stopped at the end, the bag must ac- celerate at maximum for 90 degrees, then decelerate at maximum for 90 degrees. A rough approximation of the distance travel- ed by the motor in a 90 degree turn is simply one quarter of the circumference of the bag, or 51 cm. At this point we resort to another stock equation from basic physics: x=0.5xaxt 2 In this equation x is the distance travel- ed, a is the acceleration, and t is the time required. Substituting the values from Nomad Mk II we get: 51 cm=0.5x6.9cm/sec 2 xt 2 This yields t=3.8 seconds for 90 degrees and 7.6 seconds for 180 degrees. Not very fast, but rather reasonable for our pur- poses.

These equations will give you a good estimate of the performance you can expect for any combination of motors and masses. NOMAD MK II, THE DUMB COUSIN Nomad Mk II was built, as are most of my projects, at the last minute for entry at the IPRC mentioned previously. It was not an intelligent robot, rather it could be classified as a showbot, dependant on the limited intelligence of its operator for guidance. The gas bag was a six-foot sec- tion of the Solar UFO bag inflated to give neutral (almost) bouyancy.

A simple two- channel radio control board from Radio Shack controlled the motors. The undercarriage was constructed from my low-tech laminate of l A in. Paper- coated styrofoam sheeted on both sides to 1/16 in. Balsa wood for increased strength. It is a very strong substrate and weighs about 1 gm/inr For maximum rotational speed, two motors were mounted at the ends of arms extending 25 cm to each side with a central area 10 by 6 cm for mount- ing the radio, batteries, and ballast tube. This assembly was suspended by four nylon threads from the gas bag and hung about 20 cm below the bag. The ballast tube was simply a small paper tube plugged at one end with a balsa wood dowel into which small steel ball bearings could be dropped to adjust buoyancy.

A third motor/propeller unit was mounted on the bottom of the undercarriage pointing down to control Nomad’s altitude. Batteries will be the death of me. Due to the last minute nature of Nomad Mk II’s construction, I chose to use a set of small rechargeable batteries of questionable lineage. They worked wonderfully in test flights two days before the show. Nomad performed delicate pirouettes and easily circumnavigated my front room. All was ready for the convention, or so 1 thought.

During my first day at the IPRC, I redis- covered the 14th corollary to Murphy’s Law, “Any invention will work perfectly only when no one except the inventor is look- ing.” Sure enough, during the first trial flights, the batteries went dead prematurely and would not take a charge. Subsequent investigation showed that two of the cells in one battery were hopelessly bad. As Murphy would predict, I had brought a spare of almost everything except the bat- teries.

If dark clouds can form in the Albu- querque Convention Center, then I’m sure there was one hanging over my booth. Fortunately, all was not lost. One of the greatest things about a convention like the IPRC is the comradery and spirit of gen- erosity of the people involved. In this case, my gratitude goes out to the Polaroid Cor- poration for generously providing two free “flat-pack” batteries and a plastic holder. While the batteries and holder were heavier than the originals, there was enough excess lift to complete the conven- tion competitions (and on only one set of batteries). While the convention was wonderfully enjoyable and Nomad flew well, I began to feel bad about Mk II’s stupidity. Over half the robots entered by personal roboticists were intelligent and free running.

I felt like I was cheating by controlling Nomad from the floor. Fortunately, this was exactly the motivation I needed to begin building Nomad Mk III. NOMAD MK 111, A SMART ROBOT _ First, I should admit that Nomad Mk III has never been finished. It has flown under its own guidance, but like most robots built by amateurs like myself, there is always something else to be changed or added.

Photo 1 shows the Mk III undercarriage during construction. It uses the same balsa/foam laminate as Mk II but is somewhat larger. To decrease weight, the integrated circuits are glued on their backs in “dead bug” fashion. Circuit connections are made by wire wrapping directly from lead to lead. The design was done in several blocks: input/output (sonar, com- pass, and beeper), brains (microprocessor and memory), and the flight control (motors, ballast, and fail-safe).

The I/O section provides height and direction information. The distance sensing is provided by an ultrasonic distance measuring system such as is used in auto-focus cameras. There are two sources for this module, Polaroid Cor- poration and Texas Instruments. The first module I used was the Polaroid module.

It is easier to find and works quite well, sensing distance from about 0.9 ft. With approximately 1.2 in. Un- fortunately, this module was specifically designed for use in cameras (not very sur- prising). Due to this, the drive for the cir- cuit was meant to come from switches, not integrated circuits.

The drive currents re- quired to trigger the module require separate transistors to achieve the required levels. Also, there are parts on the module for controlling a focusing motor which are not of much use in driving propellers. TI recently began selling their own ver- sion of the ranging module as the SN28827. (Incidentally, the circuitry for the original Polaroid module was custom-built by Texas Instruments.) The SN28827 is designed specifically for interface to logic circuits and is therefore somewhat lighter and smaller (see Tctble 1 for weight dif- ferences). The transducer used with both modules is made by Polaroid. The experimenter should carefully con- sider two points when using either sonar ranging module.

First, the module draws very high current in short pulses— approximately 2 A for 0.3 ms. This is not a problem for the Polaroid batteries which are designed for use with the module, but can cause horrible noise problems with small batteries and logic circuits. For this reason, Nomad Mk III uses two batteries: one for the motors and sonar and one for the microprocessor and logic.

Second, the voltage applied to the transducer is very high: about 300 V during transmit and 150 V during receive. While this can give the exprimenter a solid reminder as to what electricity is about, it is in no way harmful or life-threatening. Indeed, the only result of contact with the sensor will be a ruined range reading. What the experimenter should be very careful about is to keep the wiring from the transducer well away from 14 ROBOTICS AGE January 1985 any logic circuits since this voltage is lethal to ICs. This observation comes from ex- pensive experience. Since I wanted to sense both vertical distance above the floor and horizontal distance to objects in the room, I needed two transducers. While the transducers are rather light, the control modules are not.

I required a method for using two trans- ducers with only one module. The best answer I found was a small DIP reed relay about the same size as a 16-pin IC. The relay switches the module between the two transducers under microprocessor control. The relay does not seem to affect the ac- curacy of the ultrasonic ranging readings. A simple compass system was designed to allow Nomad Mk III to track how it was turning in the air. I disassembled a simple dime store compass approximately one inch in diameter and glued a film disk to the needle. The control system can sense angular increments of 15 degrees by shin- ing a small light-emitting diode through a light/dark pattern on the disk.

You can choose varying accuracies in your own design, but higher accuracy calls for a bet- ter compass and more careful optical design. The film disk was made by mak- ing a large drawing of the white/black pat- tern and photographing it with a 35 mm camera. The negative was cut out and became the film disk. I added a light-weight piezoelectric beeper for amusement. This type of device can be found at Radio Shack for about $2.50 and is easily worth its weight in fun. The brain chosen for the Nomad Mk III is the National Semiconductor 8073.

1 chose it for two reasons: availability (I already had one) and ease of program- ming. The 8073 has the programming language Tiny BASIC already in the pro- cessor and an RS-232 interface built in.

I would not generally recommend this device, however. First, it draws too much power. Second, BASIC is really not a very good robot programming language and is rather slow.

There are several CMOS microprocessors on the market which will save your batteries and others which have better programming languages such as Forth (my favorite) onboard. Recently, Har- ris Corporation has even produced a CMOS version of the 8088 microprocessor used in the IBM PC.

While there is no high-level language in the processor, it of- fers good speed, low power consumption, Photo 1. Close-up of the Nomak Mk III undercarriage. One of the two ultrasonic transducers is at the bot- tom of the undercarriage.

The second transducer is on the opposite side of the undercarriage. The elec- tronic components are glued to the balsa wood to conserve weight. This will be coming to you when you subscribe to Radio-Electronics » HELPFUL CONSTRUCTION ARTICLES. Test Equipment Hi-Fi Accessories Telephone Accessories Music Synthesizers Computer Equipment Automotive Equipment Intruder Alarms- Home & Car Video Accessories » NEWS ON NEW TECHNOLOGY Computers Microprocessors Satellite TV Teletext Automotive Electronics Speech Synthesizers IC Applications • FASCINATING “HOW TO DO IT’ ARTICLES. Build Your Own Projects Make Your Own PC Boards Wiring Techniques Soldering and Desoldering Design and Prototyping COMPUTERS - VIDEO - STEREO - TECHNOLOGY - SERVICE BUILD THIS ELECTRONICS SATELLITE TV STEREO IN MEDICINE. « ow '™9 es of the human R-Fs add-on for your are p ' oduceotent Reports Radio-Electronics covers all aspects of the fast moving electronics field. Featuring COMPUTERS • VIDEO • STEREO TECHNOLOGY • SERVICE COMMUNICATIONS • PROJECTS Get it all!

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46th St., Phoenix, AZ 85040 (602) 968-624 1 TWX 9 1 0-950-0 1 1 5 • Powerful 5 Amps/ • Acceleration winding Deceleration • RS232 interface • 4 axis moves 4 Motor Driver Board $175 Complete Drive package for Apple ll/Ile $265 BIG STEPPER Microprocessor Version $935 - with on-board BASIC $985 • with on-board CMC commands $1950 STEPPING MOTOR TIPS COOKBOOK $8 CENTROID (814) 237-4535 Box 739, State College, PA 1 6804 and can be programmed with any of the assemblers available on the IBM PC and PC compatibles. This would be my ideal choice. Examining the table of weights shows that standardly available ceramic pack EPROMS are very heavy. As an alternative, I used a CMOS programmable memory in a lighter weight plastic package. While the program is lost when the batteries are removed, it seemed a small price to pay for the weight savings (besides, I change the programming so often that EPROMS are too bothersome). Using the CMOS memory chip also allowed me to use the same chip for both program storage and program variables.

I used an 8255 I/O chip to control in- put and output. Again, this is not the op- timum IC due to its power consumption and a CMOS equivalent would be better.

On the good side was the fact that I already had one. Flight Control. The flight control motors require much more current than a stan- dard logic chip can supply. Two alternatives are available. The first is to build a simple two-transistor current amplifier. This re- quires some design skill, but is cheap.

A simpler alternative is a specialized chip such as the L293 four-channel driver IC made by SGS Corporation. A single 16-pin package allows you to drive two motors bidirectionally with no additional parts. This chip can drive up to 36 V devices at up to 2 A. This is far greater than the needs of any motor the gas bag can lift. Unfortunately, these parts are rather hard to find and may take several calls to local commercial electronic parts distributers to acquire, but I feel the effort is worth the simplicity. After my experiences with helium loss through the bag, I decided that some sort of processor-controlled ballast adjustment system was necessary. Any mechanical de- vice for dropping the steel bearings used in Nomad Mk II seemed too heavy (they weighed more than the ballast).

The best solution to date is my water dropper. A small plastic bottle is used to hold about half an ounce of water.

A very small pinhole is made in the bottom of the bottle. The bottle cap is modified to be air- tight and two wires are inserted through it into the air space above the water. A short coil of nichrome wire is attached in the air space to the two lead wires. With the cap in place, the bottom hole is small enough to prevent the water from dripping from the hole. However, when power is ap- plied to the nichrome wire (driven by another section of the L293) the air is heated and expands. This forces a few drops of water through the hole in the bot- tom. When power is removed from the heater, the air contracts and draws a few bubbles back into the bottle.

The process can be repeated until the water is exhausted. Having seen the Wizard of Oz many times, I also decided to add a fail-safe to the gas bag to prevent it from joining Dorothy and Toto over the rainbow should Nomad be caught in a significant updraft. A simple, lightweight solution was needed for dumping helium from the bag. I used a short (1 in.) length of soda straw fitted into the top of the gas bag.

This straw was plugged with wax and another nichrome wire coil used in the center of the wax. Should the microprocessor decide all is lost, current is applied and the wax melts, opening a vent in the top of the bag and slowly venting helium. The straw is small enough that the rate of decent is gentle and the electronics will not crash. A block diagram of the complete Nomad Mk III electronics appears in Figure 3.

NOMAD MKX, VARIATIONS ON A THEME One of the fun things about a concept like Nomad is the possibility for variation. At this time I have discarded the balsa/foam laminate and ordered an ultra-lightweight graphite sheet for the new undercarriage (definitely high-tech). Maybe you could consider solar cell power rather than bat- teries (but watch your weight). For those designing their own lightweight floater, the best references for parts and materials are the radio-controlled modeling magazines. While they don’t talk about robots, there is page after page of advertisements for lightweight materials, motors, and controls.

Of course, no one said a floating robot has to be an indoor model that fits through a door. One experimenter at the IPRC was intrigued by the idea of a large outdoor model powered by throttleable model airplane engines that could be used at high school football game half-times. Another variation for those who live near clear water is a floating submarine with a rather small gas bag and a heavier payload capability. As food for thought, what about 1 6 ROBOTICS AGE January 1985 Figure 3. Simplified block diagram for the Nomad Mk III electronics board. A giant Nomad Explorer for gas giant planets like Jupiter? The atmostphere is very dense and the robot could take ad- vantage of natural gas balloons for this pur- pose.

At least one science fiction story has dealt with balloons for this purpose. My final recommendation is simple, let your imagination go wild! Just building a copy of my Nomad would probably be frightfully boring (although I would be hap- py to correspond with those who wish to do so).

The real fun of the concept is do- ing something different. No longer will robot gatherings be limited to ground- based trundlers, the sky’s the limit. I wish to thank RB Robot Corporation for their support at the IPRC and beyond, the Polaroid Corporation for their kind donation of batteries in time of need, and NBI, Inc. For the use of their word processing system.

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