Servo magazine 04 2008

Tạp chí Servo

Vol. 6 No. 4 SERVO MAGAZINEGPSGUIDED CAR•APIS MELLIFERA•BASICBOARD•ROVIO•GECKO VAMPIREApril 2008 Cover.qxd 3/6/2008 11:23 AM Page 1 Let your geek shine. Meet Leah Buechley, developer of LilyPad—a sew-able microcontroller—and fellow geek. Leah used SparkFun products and services while she developed her LilyPad prototype. The tools are out there, from LEDs to conductive thread, tutorials to affordable PCB fabrication, and of course Leah’s LilyPad. Find the resources you need to let your geek shine too. ©2008 SparkFun Electronics, Inc. All rights reserved. »Sharing Ingenuity SPA R KF UN.COM Full Page.qxd 3/5/2008 4:10 PM Page 2 Check out the RoboNova-1 and all the other Hitec Robotics products at www.hitecrobotics.com <http://www.hitecrobotics.com> Check out the RoboNova-1 and all the other Hitec Robotics products at www.hitecrobotics.com 12115 Paine Street . Poway CA 92064 . 858-748-6948 April 25-27, 2008 University of Phoenix Stadium Glendale Arizona Visit EFExpo.com For Details J OIN U S A T +65&5 1RQ3URSRUWLRQDO &RQWLQXRXV5RWDWLRQ +656* &RUHOHVV0HJD7RUTXH 6WHHO*HDU +65+% +LJK7RUTXH .DUERQLWH*HDU +656* +LJK7RUTXH 6WHHO*HDU +657* &RUHOHVV0HJD7RUTXH 7LWDQLXP*HDU Model Gear Type Torque(oz) Speed(sec) Bearing Dimensions Weight Protocol 6V / 7.4V 6V / 7.4V L” x W” x H” (oz) HSR-8498HB Karbonite 103 / na . 0.20 / na Dual BB 1.57 x .78 x 1.45 1.75 *HMI/PWN HSR-5498SG Steel . 153 / 188 . 0.22 / 0.19 Dual BB 1.57 x .78 x 1.45 2.10 . *HMI/PWN HSR-5980SG Steel . 333 / 417 . 0.17 / 0.14 . Dual BB 1.57 x .78 x 1.45 2.36 *HMI/PWN HSR-5990TG Titanium 333 / 417 . 0.17 / 0.14 . Dual BB 1.57 x .78 x 1.45 2.39 *HMI/PWN HSR-1425CR .Nylon na / 57 16 rpm . Dual BB 1.59 x .77 x 1.44 .1.6 PWM *HMI Is Hitec’s Multi Protocol Interface which allows the programming of our servos via a PC using the optional interface kit (Part No. 78206) PWM is the standard R/C protocol and allows the programming of the robotics servos using the HFP-20 field programmer (Part No. 44430).  &RUHOHVV& V0HJ  &RUHOHVV 0HJ Don’t let your robot take a fall, make sure it can go the distance by using one of Hitec’s high powered robotics servos. From the sport level HSR-8498HB to the stump pulling torque of the Titanium geared HSR-5990TG, Hitec has a servo for your robotics project. Hitec Goes The Distance! pppgqpp g q g, Hitec has a servo for your robotics projectfor your robotics p t. Hitec Goes The Distance! Hitec Goes The Distance! Hitec Goes The Distance! Full Page.qxd 3/5/2008 4:19 PM Page 3 36 Designing and Building a Robot From Scratch by Brian Benson Part 2 covers the actual design where you determine what you need for parts and how to choose them. 42 The Gecko “Vampire” by Fred Eady Build from scratch a PIC-based step and direction controller that will act as an intelligent front end to a stepper motor drive. 50 The Making of Apis Mellifera : When PICs Fly by Tony Pratkanis and Bob Allen This build is the “bees knees” in homebrewed autonomous flying robots. 56 Turn a Kid’s Ride-on Car into a GPS Guided Autonomous Robot by John Overstrom Follow John’s first venture building a prototype vehicle that he ultimately hopes to expand into a robotic lawn mower. 64 The Appliance of Science by Peter Smith A report on the first annual Franklin Institute event. 67 Reviving an Androbot BOB by Robert Doerr BOB gets a co-processor and the gift of gab. 74 BasicBoard Robotics by William Smith Using this new development platform will make quick work of building your own bot. PAGE 50 PAGE 36 Features & Projects 4 SERVO 04.2008 TOC Apr08.qxd 3/5/2008 4:23 PM Page 4 04.2008 VOL. 6 NO. 4 SERVO 04.2008 5 Features 24 Form vs. Function: Does art have a place in combat robotics? 26 Non-Kinetic Energy Weapons 29 Manufacturing: Milling With Robots Events 31 Results and Upcoming Competitions 32 Robots at Thinktank Robot Profile 34 Roadbug 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 Departments 06 Mind/Iron 20 Events Calendar 22 New Products 40 Robotics Showcase 73 Robo-Links 81 Menagerie 87 SERVO Webstore 97 Advertiser’s Index Columns 08 Robytes by Jeff Eckert Stimulating Robot Tidbits 10 GeerHead by David Geer Rovio, Robotics House Sitter 14 Ask Mr. Roboto by Dennis Clark Your Problems Solved Here 78 Lessons From The Lab by James Isom NXT Packbot: Part 4 82 Robotics Resources by Gordon McComb Power Tools for Robot Construction 90 Appetizer by Dan Kara Robotics Events Reflect Hot Market Segments 93 Then and Now by Tom Carroll Robot Shows PAGE 10 This Month In THE COMBAT ZONE . TOC Apr08.qxd 3/5/2008 3:59 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 Bob Allen Tony Pratkanis William Smith Pete Smith Brian Benson Robert Doerr John Overstrom Dan Kara James Baker Mike Jeffries John Frizell James Isom 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. Machine Pains Place a drop of noxious fluid next to an amoeba and it swims away; place food particles nearby and it engulfs them. These instinctive or innate behaviors are critical for the amoeba’s survival. In humans and other higher organisms, pain avoidance and pleasure seeking are translated into layers of complex, learned behaviors. By virtue of feedback mechanisms that include skin temperature sensors and our visual system, for example, we learn that a gas flame is hot and painful to touch. Through learning, we associate pain with objects recently in contact with the flame and avoid damage. Although you probably don’t dwell on the survival value of your ability to avoid extreme temperatures or similar ‘painful’ situations, only the most advanced autonomous robots have been endowed with these capabilities. Truly autonomous, learning robots have mechanisms for recognizing and avoiding ‘pain.’ Recognition infers sensors of some type, and avoidance suggests an ability to associate behavior with particular combinations of sensor values. For example, a rescue robot that seeks out heat sources — presumably to differentiate injured humans from surrounding rubble — should not advance if the temperature of the heat source is above body temperature or if there is a crackling sound that increases in intensity as the robot approaches the heat source. Otherwise, the robot may move into a crackling wood fire or roaring natural gas fire and destroy itself. Sensors, then, are necessary but insufficient for learning. Moreover, the capabilities of sensors define the limits of learned behavior. In the case of the heat-seeking rescue robot, a simple IR detector would be less useful than a pyrodetector alone or, preferably, in combination with a directional microphone. In addition to sensors directed at the external environment, an autonomous, learning robot can benefit from internal sensors. The ability to monitor, for example, motor and battery temperature, battery voltage, current drawn by motors, servo or joint position, and servo or motor speed can be invaluable in avoiding internal damage. It’s non-trivial to build a robot Mind / Iron by Bryan Bergeron, Editor  Mind/Iron Continued 6 SERVO 04.2008 FIGURE 1. The CrustCrawler Smart Arm. Mind-Iron Apr08.qxd 3/4/2008 6:52 PM Page 6 with a matrix of internal and external sensors because of space and weight limitations and the limited I/O channels and processing power provided by a typical microcontroller. One solution is to use smart actuators with built-in sensors, such as the Dynamixel Actuators (www.robotis.com). As described in the March 2007 issue of SERVO, these smart actuators have built-in sensors for position, speed, load, voltage, and temperature. Moreover, the actuators are designed to be networked through a single, three- conductor cable that carries data, voltage, and ground. The AX-12+ and considerably more expensive and more powerful RX-28 and RX-64 smart actuators provide an auto-shutdown mode that responds to temperature and load extremes. Moreover, the embedded sensors can be read by a microcontroller or computer attached to the actuator network. One of my latest projects is exploring how the AX-12 based smart arm from CrustCrawler (www.crustcrawler.com) can serve as the basis of a learning, semi- autonomous arm. As shown in Figure 1, the construction of the smart arm is rather simple, thanks to sensors embedded in the actuators. In contrast, I found that adding position, speed, load, voltage, and temperature sensors to each of the six servos on CrustCrawler’s conventional SG6-UT arm impractical. The added weight of the sensors and stiffness of the cabling significantly reduce the speed and lifting capacity of the arm. Why a learning arm that’s sensitive to pain? If you’ve worked with a robot arm, you know that one of the greatest challenges is determining the allowable joint positions for a given load. Overextend a robotic arm for a given load and at best the arm simply stutters. Worst case, the servo under the most stress fails — an expensive proposition. Just as with a human arm fully extended, a robot arm is more susceptible to injury and overload for a given load. Fully contracted, the arm is stronger and capable of handling heavier loads. In a multi-jointed robotic arm, there are multiple allowable and illegal joint position configurations for a given load. These configurations can be programmed a-priori into the arm controller or computer, assuming a fixed load and operating conditions. However, change the load and mount the arm on a mobile vehicle that may be on an incline and suddenly the a-priori calculations are of little value. What’s needed is an arm in which the controller monitors the joint positions and operating parameters of each actuator and, in real-time, orchestrates movement that distributes the load to minimize changes of damage. A robotic arm should learn when not to extend a particular joint any further before it actually detects an abnormally high load. You know, for example, not to attempt to curl an automobile blocking your path. Your musculo-skeletal system also employs lower-level protective mechanisms. Sense organs in your tendons and muscles regulate how far and how fast you can move a joint. This local feedback allows you to run without hyperextending your knee joint. Furthermore, by resetting your tendon and muscle sensors (e.g., by actively stretching), you can train your joints to accept a wider range of movement. Similarly, actuators in a robot arm should learn locally and have the ability to reset or relearn range of motion and maximum speed. As noted earlier, sensors are necessary, but insufficient for association or learning. Neural networks and genetic algorithms are two often used approaches to providing robot arms with learning capabilities. Of course, you’ll need to move past a simple microcontroller to a full PC control platform to fully exploit these technologies. The USB2Dynamixel PC interface and open source VB.NET API available from the CrustCrawler website is a painless way to connect the Smart Arm or Dynamixel-based arm of your own design to a PC. Robot arms capable of learning have been described by researchers in military and academic research laboratories for over a decade. However, thanks to affordable smart actuators and control systems, you can build a system of your own. If you’d like to explore learning and robot arms, Google “root arm learning.” A particularly approachable review is available through the Space and Naval Warfare Systems Center (www.nosc.mil/robots/research/ rsmt/learning.html). SV SERVO 04.2008 7 Mind-Iron Apr08.qxd 3/4/2008 6:57 PM Page 7 8 SERVO 04.2008 Monkey to Bot Interface Successful Back in January, history was made when researchers at Duke University (www.duke.edu) via the “Network Brain Machine Interface,” connected a monkey brain’s motor and sensory cortex to a humanoid robot located at the Japan Science and Technology agency. As certain neurons fired at different phases and varying frequencies, the signals were interpreted and converted to control the robot’s legs. Thus, as the monkey walked on a treadmill, the bot imitated its movements. The monkey was provided with video feedback and apparently understood what was going on. According to Duke’s Miguel Nicolelis, “The most stunning finding is that when we stopped the treadmill and the monkey ceased to move its legs, it was able to sustain the locomotion of the robot for a few minutes — just by thinking — using only the visual feedback of the robot in Japan.” The obvious practical application relates to overcoming severe paralysis and, in fact, the next goal is to develop prototype robotic leg braces for use with humans. The bot, by the way, is a 200-lb machine with 51 degrees of freedom, developed by Sarcos (www.sarcos.com). $30 Million Purse Offered Let’s say it’s 1996 and you’re a couple of Stanford University students playing around with a new search engine concept. A decade later, your little project is raking in about $16 billion a year and, frankly, you don’t know what to do with all the money. One solution is to set up a foundation and offer to give away $30 million of it; hence, Google’s X Prize Foundation. The money is divided into a $20 million grand prize, a $5 million second prize, and another $5 million for bonuses. To claim the grand prize, you simply have to land a spacecraft on the moon and unleash a robot that travels at least 500 m and sends video, still images, and other data back to Earth. The bonus money can be had by performing additional mission tasks such as discovering water ice, roving greater than 5,000 m, and rendezvousing with old moon landing hardware. To register a team or sign up for email updates on the competition, visit www.googlelunarxprize.org. But hurry — the grand prize drops to $15 million after December 31, 2012 and disappears completely on January 1, 2015. Fill ‘er Up, Squirtbot Back when gasoline cost $0.30/gal, service stations were so eager to earn your business that they would offer free glassware and steak knives, check your oil and water, and, yes, send out a high school kid to pump the gas for you. Today, you get to pay 10 times as much for self-service, get a good whiff of the fumes, and occasionally soak your socks with unleaded. The latter may help kill the green stuff between your toes, but it can also counteract the intended effects of your aftershave, which probably cost almost as much as the This humanoid robot operates under remote monkey control. Photo courtesy of Japan Science and Technology Agency. Google Lunar X Prize launch at WIRED NextFest. Photo courtesy of Google, Inc. The return of the gas station attendant:Tankpitstop. Photo courtesy of Rotec Engineering BV. by Jeff Eckert Robytes Robytes.qxd 3/1/2008 7:59 AM Page 8 gasoline. But something resembling old-fashioned service may be returning via the Tankpitstop robotic filler developed by the Dutch company, Rotec Engineering. Its robot arm, using an array of sensors, opens your car’s filler door, unscrews the cap, inserts the fuel nozzle, and fills the tank for you. According to Rotec, it will work with any car that does not employ a filler keylock and whose physical characteristics have been stored in system memory. The $110,000 system is expected to be operating in “a handful” of Dutch stations within the year. To see it in action, visit www.rotec-engineer ing.nl/movie.html. Empty ‘er Out, Suckbot It’s not immediately clear how Alexander van der Lely came up with the “Astronaut” designation for his company’s robotic milking system, unless it has something to do with the cow that jumped over the moon. But if I were a cow, it’s sure where I’d be hanging my udders. The system, which boasts “maximum comfort and freedom” including a soft rubber floor, adjusts itself to each cow’s behavior, allowing her to choose the most comfortable milking position and either nod off or grab a snack at the same time. Her udders are pretreated with brushes to ensure optimum stimulation and the self-cleaning teat cups are fitted with pulsation units for enhanced results. According to Lely, “For the dairy cow, the Astronaut robotic milking system is democracy at its best!” Something to think about in this election year . The newest version — the A3 — is so efficient that a single dairy employee can drain 1,200,000 L (317,000 gal) out of the herd every year. This is sufficient to make more than five million bowls of cornflakes soggy, which is pretty impressive. It also incorporates a variety of features to ensure a top-notch milk harvest, including the Milk Quality Control (MQC), the Gravitor weighing unit, and digital analysis of the cows’ behavior. For details, visit www.lely.com/en/. Are You Ready for Some Football? You may be familiar with the RoboCup competition, in which teams of robots compete at “football.” But it is actually “fútbol,” better known in North America as soccer. But now, folks who prefer the American game can link up with the Robotic Football League (www.roboticfootball league.com) whose engagements are based on American Rules Football. As of this writing, the new league appears to have three teams: the Capacitors (motto: “To crush your enemies, see them drive before you, and to hear the lamentation of the women.”); the Highlanders (motto: “There can be only one”); and the Resistors (no information provided). In a recent game held at HobbyTown USA in Westminster, CO, the Resistors defeated the Capacitors 82 to 78, with the high scores resulting from each team’s inability to mount a competent defense. Teams can be made up of two, three, or six robots that throw, catch, and tackle just like the real thing. It appears that home- built bots are permitted, but at least one commercial, preassembled one is available: the 2.4 GHz radio-controlled AI-01 from Active Innovations (www. active-innovations.com). Its throwing arm can fling the ball about six feet, and it can skitter across hardwood, tile, short carpet, and other flat surfaces. The four-motor bot will cost you only $139.95, so you can afford to get in on the ground floor. Complete rules are available at the RFL website. SV Robytes “Bessie” is drained in comfort. Photo courtesy of Lely Group. The AI-01 RFL robot. Photo courtesy of Active Innovations, Inc. SERVO 04.2008 9 Robytes.qxd 3/1/2008 8:00 AM Page 9 10 SERVO 04.2008 R ovio uses a single VGA CMOS sensor to facilitate image capture and digitization so that images can be processed, stored, and transmitted over a network to the end-user via access points or the Internet. Rovio’s built-in computer “eye” operates like an IP camera on the network, according to Davin Sufer, chief technical officer of WowWee Robotics. During Rovio setup, a Wireless Access Point (WAP) assigns an Internet Protocol (IP) address to Rovio’s web server. This enables the user to connect with Rovio from any web browser across the Internet and check on things at the home front. The user can hear audio and see video that Rovio has collected during surveillance, too. During Rovio setup, software enables the user’s computer with an ActiveX control so they can use the Internet to receive compressed video and audio transmissions from Rovio. If they use the same computer to connect to Rovio remotely, they can use its Internet Explorer web browser to receive these communications. If the consumer uses another computer for remote interaction with Rovio, they will receive streaming MJPEG video only and no audio. The ActiveX control lets users stream audio from their remote PC through Rovio’s speakers, from wherever they are so long as they have an Internet connection. It also lets them hear audio from Rovio’s microphone, so they can listen in on what is happening at home. “Rovio’s owner can speak to people in the remote location (home) and hear their responses, too,” says Sufer. Three omni-directional wheels mobilize Rovio’s mechanical drive base. While the motors that drive Rovio’s wheels are still in pre- production (product not available until later this year), there are plenty of details to whet the appetite for the release of more information, and eventually Rovio itself. Rovio’s mechanized neck and sensor-equipped head rest in the down position until called upon to raise to the up position, from which it can look forward and around at children, pets, or potential intruders, or for fires or other disturbances. “The CMOS sensor can be pointed in basically any direction by moving the robot around (side to side, forwards, and backwards rotation, as well as by tilting the head upwards and downwards),” says Sufer. From its third, “looking up” position, Rovio can check people out as he travels the halls, rooms, and corners of an office or abode independently. Thanks to its NorthStar system, Rovio knows where it is in relation to its base station and the Contact the author at geercom@alltel.net by David Geer Rovio, Robotic House Sitter Out of the west rides a three-wheeled guardian named Rovio. When the family is not at home, Rovio roams, the internal landscape (carpets, hardwood floors, tile), keeping a CMOS sensor eye open at all times, monitoring property, pets, and the home environment. Photos are courtesy of WowWee. This is a front angle view of Rovio, the mobile robot, which has web cam and audio capacity. Rovio has tucked its head, web cam, and neck away atop its body. Geerhead.qxd 3/1/2008 8:25 AM Page 10