ANATOMY OF A ROBOT CHARLES M. BERGREN McGraw-Hill New York Chicago San Francisco Lisbon London Madrid Mexico City Milan New Delhi San Juan Seoul Singapore Sydney Toronto 00_200256_FM/Bergren 4/10/03 11:54 AM Page i Copyright © 2003 by The McGraw-Hill Companies, Inc. All rights reserved. Manufactured in the United States of America. Except as permitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a data- base or retrieval system, without the prior written permission of the publisher. 0-07-142930-1 The material in this eBook also appears in the print version of this title: 0-07-141657-9 All trademarks are trademarks of their respective owners. Rather than put a trademark symbol after every occurrence of a trademarked name, we use names in an editorial fashion only, and to the benefit of the trademark owner, with no intention of infringement of the trademark. 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CONTENTS Preface xv Introduction xvii Chapter 1 Project Management 1 Project Management 2 Project Process Flowchart 3 How This Works When It’s Implemented Right 5 The User’s Manual for the “Boss” 5 The User’s Manual for PMs 6 Conclusion 17 Chapter 2 Control Systems 19 Distributed Control Systems 22 Central Control Systems 24 Open-Loop Control 24 Closed-Loop Control 26 Designing the Control System 39 Notes on Robot Design 50 Multivariable Control Systems 58 Time 67 Space 69 Chapter 3 Computer Hardware 73 Leverage Existing Technology 75 Speeding Up Engineering 77 Computer Architecture 77 Process for Choosing a Robot’s Computer Hardware 113 V 00_200256_FM/Bergren 4/10/03 11:54 AM Page v For more information about this title, click here. Copyright 2003 by The McGraw-Hill Companies, Inc. Click Here for Terms of Use. Chapter 4 Reliability, Safety, and Compliance 123 Reliability 123 Safety 128 Environmental Considerations 132 Common Sense 135 Emissions 138 Quality Issues 143 Testing 144 Chapter 5 Design Steps: HLD 147 Power 147 Locomotion 148 Automation 148 Chapter 6 Energy and Power Systems 153 Energy 154 Energy Sources 157 Chapter 7 Energy Control and Software 159 Considerations 159 Energy Conservation 162 Hardware Considerations 164 Spy-hopping 176 Software Considerations for Energy Control 178 Mechanical Considerations: Software for Energy Control 183 Chapter 8 Digital Signal Processing (DSP) 191 The Nyquist-Shannon Sampling Theorem 192 A/D Conversion 198 A/D Dithering 200 Sample and Hold (S/H) 201 Antialias Filters 201 D/A Effects: Sinc Compensation 207 DSP Filter Design 208 VI CONTENTS 00_200256_FM/Bergren 4/10/03 11:54 AM Page vi Physical Implementation of DSP Filters 215 Multirate DSP 220 Chapter 9 Communications 221 OSI Seven-Layer Model 224 Physical Layer 226 Baseband Transmission 228 Modulated Communications 232 Error Control 238 Shared Access 258 Compression 265 Encryption and Security 266 Popular Communication Channels 269 Chapter 10 Motors and Actuators 275 AC Motors 275 DC Motors 276 Exotic Motors 279 Chapter 11 Mechanics 281 Materials 282 Some Cautions 285 Static Mechanics 287 Dynamic Mechanics 288 Index 293 CONTENTS VII 00_200256_FM/Bergren 4/10/03 11:54 AM Page vii This page intentionally left blank. IX PREFACE T wo years ago, I took my six-year-old son to a “robot race” up in the Rockies near Boulder. It was held in the community center of a small mountain town. Nevertheless, it was packed with about 100 enthusiastic people and many interesting exhibits. The central event was to be a timed race along a prescribed course. Several school-aged kids had entered plastic robots clearly built from parts from the same toy manufacturer. The racecourse was a plastic mat approximately 15 feet on each side. The robots had to fol- low a one-inch-wide, serpentine black line on the mat from beginning to end. The win- ner would be the robot finishing with the fastest time. I watched the kids tuning up their robots on the racecourse before the race. Each robot had a sensor on each side that could detect the black line. If the robot moved forward and started to cross the line, the electronics would correct the steering and move the robot back on course. It was clear the kids were all having trouble. None of the robots could follow the course from beginning to end. They would invariably lurch too far over the black race- course line and get lost, spinning in useless circles. Legions of adult advisors huddled with the kids, making all sorts of changes, yet nobody was making progress. To me, the answer was obvious and I wanted to help. 00_200256_FM/Bergren 4/10/03 11:54 AM Page ix Copyright 2003 by The McGraw-Hill Companies, Inc. Click Here for Terms of Use. [...]... of an energyefficient robot I mentioned many considerations that should be kept in mind during the selection and design of robotic software The chapter outlines a coordinated approach to the selection of a processor, a battery, a power supply, operating software, and application software Included are many software techniques that have proven successful, including a discussion of braking methods Chapter... tank with the appropriate amount of water, and reliability is paramount The average toaster is great at browning bread in a repeatable manner You can probably walk through a completely dark room, touch a few well-known milestones, reach out with your hand, and find the light switch almost every time We all take the existence of such control systems for granted Let’s assume we’ve already built a large,... was clear some of them understood what was going on To make a long story short, Sam’s robot reliably chugged around the racecourse and he won The look on his face alone was worth the effort Sam’s nominal reward was a kit for a bigger robot, but I think he walked away with much more than that After the race, Sam was eager to know how I knew the solution I took Sam aside and gave him a glimpse of the... sizes, and they are executed in all shapes and forms This document provides a standard way to manage projects that is known to all responsible parties It provides management tools that PMs can use to alter the course of a project and make corrections This makes information easier to find, decreases the amount of negotiations involved, provides reliable channels of communication, and brings a level of comfort... the racecourse line towing the camera Sam took the batteries out of the camera until it was near the right weight All too soon, race time came and we had to halt our experiment One after another, the older competitors’ robots raced down the course only to stray off the black line and be disqualified A couple of the robots did finish after wandering around lost and wasting a good deal of time Eventually,... this a step further, let me teach you something about the “nontechnical” art of project management first It’s a little known fact, but practicing a bit of project management makes it far less likely that your robot will run amuck and blow up the planet or that your family members will have to change their names to show their faces in public Project Management Classically, a project is an endeavor to carry... outset Certainly, a project can be executed and managed in almost any manner To bring order to the situation, and to give all participants a clear picture of what’s expected, it makes sense to use established methods and rules The following discussion lays out the basics of project management processes but omits some of the details and reasoning to make it more readable Projects come in all shapes and sizes,... such a control system are also given Last of all, I’ve thrown in all the tricks of the trade that I know Chapter 3 covers computer hardware I’ve outlined many of the reasons for using a computer in a robot and ways to accelerate the design process Several computer architectures are listed, including analog, general-purpose digital, DSP, neural networks, and parallel processors I’ve outlined the basic architecture... project plan can be submitted and reviewed in parallel with the project proposal The plan should be written so it can be understood and used by someone unacquainted with the project The plan’s schedule can be drawn up using a standard software package (such as Microsoft Project) in a Gantt bar chart format (about 10 to 20 bars) A portion of such a Gantt chart is shown in Figure 1-2 It’s large enough... as well Chapter 11 covers mechanics and covers the selection and the relevant properties of materials Many robots have mechanical problems, so several design tips are included In addition, short sections are dedicated to static and dynamic calculations 1 PROJECT MANAGEMENT Act 1 Scene 1: The graying professor stands in his graying tweed suit in an overly heated classroom with high windows and ceramic . 0-07-141657-9 All trademarks are trademarks of their respective owners. Rather than put a trademark symbol after every occurrence of a trademarked name, we use names. subject of a separate chapter. Each chapter will cover the basics but will also lead you to theory and reasoning that can capture the imagination. For each