Tạp chí Servo
04 74470 58285 08> U.S. $5.50 CANADA $7.00 Vol. 6 No. 8 SSEERRVVOO MAGAZINEDARPA AT THE GRAND PRIX•RC ROBOTICS•CPLD SERVO DRIVER•VEX MOTOR PWMAugust 2008 Cover.qxd 7/9/2008 1:54 PM Page 1 Let your geek shine. Meet Pete Lewis, lead vocalist for the band Storytyme. Pete recently created the RS1000, a new personal monitor system for performing musicians. It was SparkFun’s tutorials, products and PCB service that enabled him to take his idea to market in less than a year. The tools are out there. Find the resources you need to let your geek shine too. ©2008 SparkFun Electronics, Inc. All rights reserved. Hear music from Storytyme at www.storytymeband.com, or check out Pete’s RS1000 at www.rockonaudio.com. Sharing Ingenuity WWW.SPARKFUN.COM Full Page.qxd 7/9/2008 9:57 AM Page 2 a) Science b) Te c h nolog y c) Engineering d) Mathematics e) All of the above Given a choice, middle and high school students prefer robotics among science courses. And our Classroom Lab Kits make it easier than ever to bring VEX Robotics to your school while making your budget go farther. With standards-based curriculum available from Intelitek, Carnegie-Mellon and Autodesk, VEX is quickly becoming the robotics platform of choice among schools internationally. We now offer local, regional, national and international competitions for students to test their skill and express themselves. Visit RobotEvents.com for event information. Only one choice is clear when considering an educational robotics platform – the VEX Robotics Design System. Studies prove what we at VEX ® already knew . Students love Robotics. Classroom Lab Kit bundles start at $549 A product of Innovation First. Copyright 2008. Innovation First, Inc. Think. Vex.Amaze.Build.Create. VISIT WWW. VEXROBOTICS .COM Full Page.qxd 7/9/2008 10:18 AM Page 3 Features 28 BUILD REPORT: Combat Robot: $1.25 a Pound 32 PARTS IS PARTS: Power Switches Events 30 Results and Upcoming Competitions 30 Event Report: Mall of America Rotunda Rumble Robot Profile 33 Touro 06 Mind/Iron 24 Events Calendar 26 New Products 44 Robotics Showcase 66 Robo-Links 73 SERVO Webstore 81 Advertiser’s Index Columns 08 Robytes by Jeff Eckert Stimulating Robot Tidbits 10 GeerHead by David Geer MAARS Robots Taking Off for War 14 Twin Tweaks — Special Edition by Bryce and Evan Woolley Rhyme of the Modern Submariner 20 Ask Mr. Roboto by Dennis Clark Your Problems Solved Here 62 Robotics Resources by Gordon McComb Robotics via Remote Control 67 BasicBoard Robotics by William Smith Moving From BS1 to PIC 76 Appetizer by John Sosoka The Greatest Playground of All 78 Then and Now by Tom Carroll Robots — How We ’ve Built Them Over the Years PAGE 10 PAGE 14 4 SERVO 08.2008 THE COMBAT ZONE . Departments TOC Aug08.qxd 7/9/2008 4:04 PM Page 4 08.2008 VOL. 6 NO. 8 SERVO 08.2008 5 36 The CPLD Servo Driver by Fred Eady Driving hobby servos is only one of the tricks a CPLD can perform. In addition to turning servo rotors, you can also use a CPLD to replace a number of discreet logic ICs in your next robotic design. 46 Build a PWM Circuit to Run a Vex Motor by John Toebes You don’t just have to use NiCad batteries to drive a Vex motor. 49 Look Ma, No Driver! by Jason Bardis Autonomous DARPA vehicles take center stage (track!) at the Long Beach Grand Prix. 55 Build the Ultimate Robot by Michael Simpson If you’re not afraid to part with a little cash, this series will give you the choice of building either a six- or three-wheeled robot with an onboard PC. SERVO Magazine (ISSN 1546-0592/CDN Pub Agree#40702530) is published monthly for $24.95 per year by T & L Publications, Inc., 430 Princeland Court, Corona, CA 92879. PERIODICALS POSTAGE PAID AT CORONA, CA AND AT ADDITION- AL ENTRY MAILING OFFICES. POSTMASTER: Send address changes to SERVO Magazine, P.O. Box 15277, North Hollywood, CA 91615 or Station A, P.O. Box 54,Windsor ON N9A 6J5; cpcreturns@servomagazine.com PAGE 46 PAGE 28 PAGE 36 Features & Projects TOC Aug08.qxd 7/9/2008 5:14 PM Page 5 Published Monthly By T & L Publications, Inc. 430 Princeland Court Corona, CA 92879-1300 (951) 371-8497 FAX (951) 371-3052 Webstore Only 1-800-783-4624 www.servomagazine.com Subscriptions Toll Free 1-877-525-2539 Outside US 1-818-487-4545 P.O. Box 15277 North Hollywood, CA 91615 PUBLISHER Larry Lemieux publisher@servomagazine.com ASSOCIATE PUBLISHER/ VP OF SALES/MARKETING Robin Lemieux display@servomagazine.com EDITOR Bryan Bergeron techedit-servo@yahoo.com CONTRIBUTING EDITORS Jeff Eckert Tom Carroll Gordon McComb David Geer Dennis Clark R. Steven Rainwater Fred Eady Kevin Berry Bryce Woolley Evan Woolley Jason Bardis John Toebes Michael Simpson John Sosoka Tim Wolter Aaron Nielsen Chad New William Smith CIRCULATION DIRECTOR Tracy Kerley subscribe@servomagazine.com MARKETING COORDINATOR WEBSTORE Brian Kirkpatrick sales@servomagazine.com WEB CONTENT Michael Kaudze website@servomagazine.com PRODUCTION/GRAPHICS Shannon Lemieux Joe Keungmanivong ADMINISTRATIVE ASSISTANT Debbie Stauffacher Copyright 2008 by T & L Publications, Inc. All Rights Reserved All advertising is subject to publisher’s approval. We are not responsible for mistakes, misprints, or typographical errors. SERVO Magazine assumes no responsibility for the availability or condition of advertised items or for the honesty of the advertiser.The publisher makes no claims for the legality of any item advertised in SERVO. This is the sole responsibility of the advertiser. Advertisers and their agencies agree to indemnify and protect the publisher from any and all claims, action, or expense arising from advertising placed in SERVO. Please send all editorial correspondence, UPS, overnight mail, and artwork to: 430 Princeland Court, Corona, CA 92879. Next Level Robotics To an outsider looking in at amateur robotics, it often appears that the field hasn’t evolved much in the past few years. Certainly, there have been evolutionary gains. Sensors are a little smaller and smarter, and motors and controllers are a little more powerful and sophisticated. Furthermore, there have been a few advances in microcontrollers, such as the development of the Parallax Propeller, and more powerful field programmable gate arrays or FPGAs. Despite incremental advances in the components we use to construct robots, the fundamental capabilities of carpet roamers, crawlers, and arms haven’t changed much. The leading edge of low-cost robotics is often represented by toys carried by the major retail outlets. So what’s it going to take to get amateur robotics to the next level? That is, to a level that not only matches the capabilities illustrated by commercial and academic robotics, but that at least hints at the capabilities we ascribe to robots depicted in Star Wars and Transformers? First, a reality check. Developing a semi-autonomous Martian rover or a robotic prosthetic arm for a soldier injured in Iraq takes significant financial resources and teams of engineers, scientists, and machinists. So what can you do, given the current economic environment, to move your robot designs to the next level? The most fertile area in robotics yet to be fully exploited that is within reach of every roboticist is software development. For example, in the area of robot vision, there is a need to better recognize, track, and differentiate objects, to read facial expressions and gestures, and — in general — to make robots more socially adaptable. If your interest is outdoor navigation, then there is a world of software options to explore, from GPS-based localization to navigation with light and RF beacons. Means of providing robots with the ability to maneuver through mazes and how to best avoid ledges and low-traction areas have yet to be perfected. Connected to a PC, your robotic arm or vehicle with appropriate sensors can become just as sophisticated as any rover developed by NASA. Of course, you can work on challenges completely within a computer using simulations. And that’s an efficient, low-cost method. However, at some point you have to validate your work on a real robot. One thing I’ve learned over several years of building robots is that unless you’re working on a specific hardware specification, you’ll make more progress in shorter time if you leave the design of the hardware platform to someone else and focus on the overall functionality. For example, why spend months designing and building an arm when you can buy a kit from Lynxmotion (www.lynxmotion.com) or CrustCrawler (www.crustcrawler. com)? Even if you have to modify an off-the-shelf arm, you’ll likely still save time and money. I’ve used various versions of the CrustCrawler arm — Mind / Iron by Bryan Bergeron, Editor Mind/Iron Continued 6 SERVO 08.2008 Mind-Iron Aug08.qxd 7/9/2008 8:10 PM Page 6 SERVO 08.2008 7 Wearable Sensors Conceived at Harvard Robotics Lab Measure Hand Forces FingerTPS™ Put Comfortable Tactile Sensors at Your Fingertips . Literally P ressure Profile Systems, Inc. (PPS), had just released their innovative new wireless FingerTPS™ (Finger Tactile Pressure Sensing) system for immediate sale worldwide. FingerTPS sensors are soft, flexible sensors worn on the hand that transmit accurate, repeatable tactile force data to a PC via wireless Bluetooth connection. FingerTPS tactile data with integrated video provides a complete representation of user interaction with tools, sports equipment, new product designs, and medical applications. "The FingerTPS concept was originally funded by DARPA research grants to capture the forces of a skilled surgeon for developing virtual surgical simulation systems. After a decade of numerous iterations, we finally have a system that is easy to use," said Dr. Jae Son, CEO of PPS. The wireless FingerTPS system was unveiled to the public at the IVR Industrial Virtual Reality Expo in Tokyo, Japan this last June. "The wireless capability and the simple, one-touch calibration were the most exciting features among attending engineers and researchers from hundreds of leading firms," said David Ables, CTO of PPS. FingerTPS was recently featured in programming on the National Geographic Channel and Fox Sports Net. Episodes of "SportScience" and "FightScience" called on PPS and industry experts to scientifically explain the performance of world-class athletes including NFL Hall of Fame receiver Jerry Rice, NBA sharpshooter Jason Kapono, and Mixed Martial Arts legend Randy Coture. "For elite athletes like Jerry Rice or Jason Kapono, their hands are their livelihood, and they readily grasped how real-time tactile data could help evaluate and improve their performance," explained Ables. FingerTPS systems start at a mere $4,995 for a single-hand system with two sensors that are available in multiple sizes in specialized shapes for fingers, thumbs, palms, and inner phalanges. FingerTPS systems also include a video camera for synchronized video input, software, and a reference sensor for easy, one-touch calibration. Pressure Profile Systems, Inc., was founded in 1996 by two graduates from the Harvard University Robotics Lab. Government grants and industrial sales have enabled PPS tactile sensing technology development for medical devices, industrial instruments, and consumer electronics. For more information, visit the PPS website at ww.pressureprofile.com. including their latest Smart robotic arm — as the basis for many projects that rely on the processing power of a PC. Both CrustCrawler and Lynxmotion offer PC-based software to control their arms, and third party software is available, as well. Similarly, you needn’t start your software designs from scratch or with a huge budget. The entry-level versions of the various Microsoft .Net compilers and the MS Robotics Studio can be freely downloaded. If you’re not a Microsoft fan, there are dozens of software options, from MatLab and Simulink (www.mathworks.com) to open-source compilers. If possible, leverage what’s been done before and move to the next level more quickly and easily. Just be sure t o return the favor and post your software to the web – and consider sharing your experience with SERVO readers. I don’t want to discourage mechanical engineers and engineers-in- training from tackling new hardware designs. If you have a machine shop at your disposal and the skill to use those tools, then don’t hesitate. Everyone has different goals and ideas of what they want to get out of robotics. However, if getting to the next level quickly on a limited budget is your focus, then you should at least consider focusing on the brains — as opposed to the brawn — of your robots. SV FAST FAQs What is the maximum pressure range that PPS sensors can reach? PPS industrial sensors can reach pressure ranges of up to 2,000 psi. However, currently PPS can only guarantee factory calibration at pressures up to 700 psi. What is the maximum speed of the PPS sensors? TactArray systems have an element-to-element scan speed of up to 10 kHz. ConTacts systems have a continuous analog output allowing any sampling rate, but the sensors have a throughput of approximately 2 kHz. Of what materials are PPS sensors made? PPS sensors are made from conductive cloth (conformable), Kapton (industrial), Lycra (stretchable) or a combination of conductive cloth and Kapton (hybrid). What is the smallest element size for PPS sensors? Element sizes in TactArray sensor arrays can be as small as 1mm x 2 mm, however, practical resolution is actually much greater. PPS's pressure-sensing technology allows accurate pressure interpolation between sensing elements. Single-element ConTacts sensors have been built as small as 5 mm x 5 mm. Are PPS sensors waterproof? PPS sensors are NOT waterproof, however, PPS can provide removable waterproof sheaths to protect the sensors or complete encapsulation for more rugged environments. Mind-Iron Aug08.qxd 7/9/2008 1:54 PM Page 7 8 SERVO 08.2008 New Hopperbot Sets Record Mechanical jumpers are nothing new, but one that was unveiled at the IEEE International Conference on Robotics and Automation appears to have, um, leaped ahead of its com- petitors in terms of jump distance. The tiny, 7 g mechanical grasshopper can jump 1.4 m, which is said to be 10 times farther — relative to its size — than any other existing jumping robot. The little bug was developed at the Laboratory of Intelligent Systems at the Ecole Polytechnique Federale de Lausanne (EPFL, www. epfl.ch), and, according to Prof. Dario Floreano, “This biomimetic form of jumping is unique because it allows microrobots to travel over many types of rough terrain where no other walk- ing or wheeled robot could go. These tiny jumping robots could be fitted with solar cells to recharge between jumps and deployed in swarms for extended exploration of remote areas on Earth or on other planets.” The bot mimics the way fleas, locusts, and other pests travel by charging two torsion springs via a small 0.6 g pager motor and a cam. To optimize jump performance, the legs can be adjusted for jumping force, take-off angle, and force profile during the acceleration phase. An on-board battery allows it to make up to 320 jumps at 3 second intervals. Microbots Self Organize Down on the MEMS level, Duke University (www.duke.edu) researchers have been training micro- bots to maneuver separately, without any obvious guidance, and assemble themselves into organized structures. The devices — which are basically shaped like a spatula — can display surprisingly flexible movements. In one experiment, two of them were taught to pirouette to Strauss music on a tiny “dance floor.” In the accompanying photo, four of them numbered 1, 2, 4, and 5 (no. 3 was probably somewhere being questioned by Mike Nifong), started at the corners of a rectangle a bit smaller than one square mm. Next, two species (4 and 5) docked to form the initial stable shape, after which the others joined to form the final assembly. The devices measure about 60 x 250 x 10 µm and draw power from an electrified surface. They take steps of only 10 to 20 nm but can make up to 20,000 movements per second. The only speculation about practical applications cited the ability to move around the interiors of laboratory-on- a-chip devices. But they’ll probably come up with something more provocative. Robofish in School Most subaquatic robots need to communicate with human beings from time to time, often via communication satellites during operation. But the University of Washington (www.washington.edu) is developing fin-propelled Robofish that can skip the middle man and work cooperatively with each other until their task is complete. Kristi Morgansen, UW assistant professor of aeronautics and astronautics, recently ran them in a school of three as their first major test, in which they were programmed to either swim all in one direction or all in different directions. The latter doesn’t sound like much of an accomplishment, being essentially what would happen if you turned three flies loose in your living room. But bigger things are planned. The researchers trained some live fish to respond to a stimulus by swimming into a feeding area. They discovered that you only have to train about a third of the fish to get the entire school to act in unison. “The fish that have a strong idea tend to dominate over those This mechanical grasshopper can leap 27 times its body size. Photo courtesy of EPFL. Microassembly experiment recorded via optical microscope. Image courtesy of Duke University. Fin-propelled Robofish (shown with a penny) is about the size of a 10 lb tuna. Photo courtesy of the University of Washington. bbyy JJeeffff EEcckkeerrtt RRoobbyytteess Robytes.qxd 7/8/2008 10:25 AM Page 8 that don’t,” according to Morgansen. “That has implications for what will happen in a group of vehicles. Can one vehicle make the rest of the group do something just based on its behavior?” Like the live fish, the robotic ones communicate with each other, in this case using low-frequency sonar. Test results showed that although only about half of the transmitted communications actually get through, the Robofish programming allowed them to accom- plish their task anyway. The next step will be to let them loose in the ocean, where they will be programmed to trail a remote-controlled toy shark. Ultimately, they could be dispatched to explore caves and ice-covered waters, track whales, map regions of pollution, or harass baby seals. Walk Like a Man Most bots walk in the rigid, clunky movements that are typical of industrial machinery, toy robots, and people who buy their shoes at Wal-Mart. This differs from the much more fluid way humans generally move, which basically consists of falling forward in a controlled manner. But, in pursuit of a PhD, researcher Daan Hobbelen of the Delft University of Technology (TU Delft) has developed an advanced robot, called Flame, that demonstrates that a robot can be human-like, energy-efficient, and highly stable. The overall goal is to provide insight into how people walk, which ultimately can be applied to helping people with mobility problems via improved diagnosis and rehab. Flame employs seven motors, a balance organ, and some propri- etary algorithms to ensure a high level of stability. The robot can, for example, apply the information provided by its balance organ to place its feet slightly farther apart to prevent falling. According to Hobbelen, Flame’s advanced ankles have already provided motion scientists with advanced insight into how the complicated joint works. For details, visit www.dbl.tudelft.nl. TP-Bot Wins Award LEGO’s 2008 Earth Day Building Challenge was to create a MINDSTORMS NXT robot that “could be used to help maintain a healthy, sustainable environment.” The Champion’s Award went to Dino Martino’s TP-Bot 2008, which helps save energy and the environment via the efficient dispensing of toilet paper. The bot is compatible for use by up to five different people (presumably not all at once), and it includes a scanner (to which users present an access pass and a four-digit secret code) and a paper dispensing system. It even monitors how much toilet paper is left on the roll. Can’t you feel the greenhouse gases abating already? For info on this and others in the winners’ circle, visit mindstorms.lego.com/news/. New Hall of Fame Inductees In case you missed it, the 2008 inductees into the Carnegie Mellon Robot Hall of Fame (www.robothallof fame.org) are the Raibert Hopper, NavLab5, LEGO® Mindstorms, and Lt. Cmdr. Data. The Hopper (shown in the photo) was developed in 1983-84 for experiments on active balance and dynamics in legged locomotion. Named for its developer, Marc Raibert, the one-legged bot could hop in place or run at a top speed of 2.2 m/sec (4.8 mph). Congrats to all. SV RRoobbyytteess Robot “Flame” walks like a human. Photo courtesy of TU Delft. SERVO 08.2008 9 The award-winning TP-Bot 2008. Photo courtesy of LEGO. The Raibert Hopper. Photo courtesy of MIT. Robytes.qxd 7/8/2008 10:25 AM Page 9 10 SERVO 08.2008 I n 2005, I covered the SWORDS (Special Weapons Observation Reconnaissance Direct-action System) maneuverable military robots, which soldiers use as scouts and remote weapons systems in the war in Iraq. As reported, the SWORDS iteration of the robotic sentry is compatible with M16s, M240s, M249s, Barrett 50 calibers, 40 mm grenade launchers, or M202 anti-tank rocket systems. The SWORDS have many other features including advanced sensing. The robots use these technologies to locate enemy combatants, IEDs (Improvised Explosive Devices), and other hazards. The SWORDS are unmanned ground vehicles (UGVs), which means that threats to these vehicles in their everyday line of work don’t directly threaten the soldiers who operate them from a safe distance via a remote control console. Since the Defense Authorization Bill for Unmanned Vehicles, the armed forces have been pressed to convert the vast majority of ground combat vehicles to unmanned for this very reason. The war and the need to keep soldiers further out of risk has brought us to the latest evolution of the unmanned fighter. The newly released MAARS (Modular Advanced Armed Robotic System) is the offspring of the SWORDS and “the first fully modular ground robot system capable of providing a measured response including nonlethal, less lethal, and even lethal stand-off capabilities,” says a June 4th media release from QinetiQ, owner of Foster-Miller, which produced the robots. If you’ve heard references to SWORDS 2.0, these are the MAARS robots. Soldiers will be able to supplement the three existing SWORDS robots which are deployed in Iraq with these robots. The Federal government and QinetiQ have been working on MAARS for 18 months to deliver a robot system that is armed, unmanned, and controlled by the soldiers themselves, according to the release. MAARS will replace SWORDS as the core platform for building out these kinds of systems for battlefield tactics. Because the new MAARS platform is standardized and modular, it will make it affordable for the military to have more of the robots and to repair them more readily. QinetiQ worked closely with the military to ensure that the MAARS robot would “enhance the war fighter’s capability and lethality, extend his situational awareness, and provide all these capabilities across the spectrum of combat,” says Dr. William Ribich, President of the Technology Solutions Group, QinetiQ North America. By extending the capabilities of MAARS, soldiers can save their lives and the lives of area non-combatants more frequently. MAARS Mayhem Unlike SWORDS, MAARS gives the human operator choices for confrontation on the battlefield. For nonlethal confrontation, a human operator can project their voice or a siren through mounted speakers to a person or crowd, or emit a green pulsing laser light that is visually confusing, though harmless. When a confrontation calls for more, soldiers use MAARS to disperse Contact the author at geercom@alltel.net by David Geer MAARS Robots Taking Off for War SWORDS Military Robots Graduating to 2.0, MAARS Status Here is the new MAARS robot — the larger offspring to the SWORDS robot. Four grenade launchers, machine gun, turret, other equipment, and tracks visible. Geerhead.qxd 7/8/2008 10:16 AM Page 10