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robot mechanisms and mechanical devices illustrated paul e sandin mcgraw-hill new york chicago san francisco lisbon london madrid mexico city milan new delhi san juan seoul singapore sydney toronto[close]
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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 database or retrieval system without the prior written permission of the publisher 0-07-142928-x the material in this ebook also appears in the print version of this title 0-07-141200-x 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 where such designations appear in this book they have been printed with initial caps mcgraw-hill ebooks are available at special quantity discounts to use as premiums and sales promotions or for use in corporate training programs for more information please contact george hoare special sales at george_hoare@mcgrawhill.com or 212 904-4069 terms of use this is a copyrighted work and the mcgraw-hill companies inc mcgraw-hill and its licensors reserve all rights in and to the work use of this work is subject to these terms except as permitted under the copyright act of 1976 and the right to store and retrieve one copy of the work you may not decompile disassemble reverse engineer reproduce modify create derivative works based upon transmit distribute disseminate sell publish or sublicense the work or any part of it without mcgraw-hill s prior consent you may use the work for your own noncommercial and personal use any other use of the work is strictly prohibited your right to use the work may be terminated if you fail to comply with these terms the work is provided as is mcgraw-hill and its licensors make no guarantees or warranties as to the accuracy adequacy or completeness of or results to be obtained from using the work including any information that can be accessed through the work via hyperlink or otherwise and expressly disclaim any warranty express or implied including but not limited to implied warranties of merchantability or fitness for a particular purpose mcgraw-hill and its licensors do not warrant or guarantee that the functions contained in the work will meet your requirements or that its operation will be uninterrupted or error free neither mcgraw-hill nor its licensors shall be liable to you or anyone else for any inaccuracy error or omission regardless of cause in the work or for any damages resulting therefrom mcgraw-hill has no responsibility for the content of any information accessed through the work under no circumstances shall mcgraw-hill and/or its licensors be liable for any indirect incidental special punitive consequential or similar damages that result from the use of or inability to use the work even if any of them has been advised of the possibility of such damages this limitation of liability shall apply to any claim or cause whatsoever whether such claim or cause arises in contract tort or otherwise doi 10.1036/007142928x[close]
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for more information about this title click here contents introduction acknowledgments xi xxxv 1 3 4 5 5 7 8 9 9 10 10 11 15 16 18 19 20 20 21 22 23 24 29 30 31 31 31 v copyright © 2003 by the mcgraw-hill companies inc click here for terms of use chapter 1 motor and motion control systems introduction merits of electric systems motion control classification closed-loop system trapezoidal velocity profile closed-loop control techniques open-loop motion control systems kinds of controlled motion motion interpolation computer-aided emulation mechanical components electronic system components motor selection motor drivers amplifiers feedback sensors installation and operation of the system servomotors stepper motors and actuators for motion control permanent-magnet dc servomotors brush-type pm dc servomotors disk-type pm dc motors cup or shell-type pm dc motors position sensing in brushless motors brushless motor advantages brushless dc motor disadvantages characteristics of brushless rotary servomotors linear servomotors[close]
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vi contents commutation installation of linear motors advantages of linear vs rotary servomotors coil assembly heat dissipation stepper motors permanent-magnet pm stepper motors variable reluctance stepper motors hybrid stepper motors stepper motor applications dc and ac motor linear actuators stepper-motor based linear actuators servosystem feedback sensors rotary encoders incremental encoders absolute encoders linear encoders magnetic encoders resolvers tachometers linear variable differential transformers lvdts linear velocity transducers lvts angular displacement transducers atds inductosyns laser interferometers precision multiturn potentiometers solenoids and their applications solenoids an economical choice for linear or rotary motion technical considerations open-frame solenoids c-frame solenoids box-frame solenoids tubular solenoids rotary solenoids rotary actuators actuator count debugging reliability cost 34 35 36 37 37 38 38 38 40 41 42 43 43 44 46 47 48 49 51 53 55 55 57 57 59 60 60 62 63 63 63 64 64 66 67 67 68 68 chapter 2 belts indirect power transfer devices 69 72[close]
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contents vii flat belts o-ring belts v-belts timing belts smoother drive without gears plastic-and-cable chain chain ladder chain roller chain rack and pinion chain drive timing or silent chain friction drives cone drive needs no gears or pulleys gears gear terminology gear dynamics terminology gear classification worm gears worm gear with hydrostatic engagement controlled differential drives twin-motor planetary gears provide safety plus dual-speed harmonic-drive speed reducers advantages and disadvantages flexible face-gears make efficient high-reduction drives high-speed gearheads improve small servo performance simplify the mounting cost-effective addition 73 73 73 75 76 77 79 80 80 82 82 83 84 85 87 88 88 90 90 93 95 96 99 100 102 102 104 chapter 3 direct power transfer devices 107 109 110 114 114 115 117 118 118 120 121 121 125 couplings methods for coupling rotating shafts ten universal shaft couplings hooke s joints constant-velocity couplings coupling of parallel shafts ten different splined connections cylindrical splines face splines torque limiters ten torque-limiters one time use torque limiting[close]
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viii contents chapter 4 wheeled vehicle suspensions and drivetrains 127 130 130 131 134 136 141 144 150 155 wheeled mobility systems why not springs shifting the center of gravity wheel size three-wheeled layouts four-wheeled layouts all-terrain vehicle with self-righting and pose control six-wheeled layouts eight-wheeled layouts chapter 5 tracked vehicle suspensions and drive trains 161 167 168 171 174 178 178 179 180 181 184 steering tracked vehicles various track construction methods track shapes track suspension systems track system layouts one-track drive train two-tracked drive trains two-tracked drive trains with separate steering systems four-tracked drive trains six-tracked drive trains chapter 6 steering history 187 190 193 steering basics the next step up chapter 7 walkers 199 202 203 208 208 208 211 214 214 leg actuators leg geometries walking techniques wave walking independent leg walking frame walking roller-walkers flexible legs[close]
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contents ix chapter 8 pipe crawlers and other special cases 217 220 221 222 223 224 224 226 226 horizontal crawlers vertical crawlers traction techniques for vertical pipe crawlers wheeled vertical pipe crawlers tracked crawlers other pipe crawlers external pipe vehicles snakes chapter 9 comparing locomotion methods 227 229 229 230 231 232 232 233 233 234 235 235 236 236 237 what is mobility the mobility system size efficiency the environment thermal ground cover topography obstacles complexity speed and cost the mobility index comparison method the practical method explain all this using the algebraic method chapter 10 manipulator geometries 239 241 243 243 245 246 247 248 250 252 255 256 positioning orienting how many degrees of freedom e-chain slider crank arm geometries cartesian or rectangular cylindrical polar or spherical the wrist grippers passive parallel jaw using cross tie passive capture joint with three degrees of freedom[close]
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x contents industrial robots industrial robot advantages trends in industrial robots industrial robot characteristics 258 259 259 261 chapter 11 proprioceptive and environmental sensing mechanisms and devices 263 270 276 277 278 279 280 282 283 284 284 285 286 287 289 291 industrial limit switches layouts combination trip sense and hard stop by-pass layouts reversed bump bumper geometries and suspensions simple bumper suspension devices three link planar tension spring star torsion swing arm horizontal loose footed leaf spring sliding front pivot suspension devices to detect motions in all three planes conclusion index[close]
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introduction t his book is meant to be interesting helpful and educational to hobbyists students educators and midlevel engineers studying or designing mobile robots that do real work it is primarily focused on mechanisms and devices that relate to vehicles that move around by themselves and actually do things autonomously i.e a robot making a vehicle that can autonomously drive around both indoors and out seems at first like a simple thing build a chassis add drive wheels steering wheels a power source usually batteries some control code that includes some navigation and obstacle avoidance routines or some other way to control it throw some bump sensors on it and presto a robot unfortunately soon after these first attempts the designer will find the robot getting stuck on what seem to be innocuous objects or bumps held captive under a chair or fallen tree trunk incapable of doing anything useful or with a manipulator that crushes every beer can it tries to pick up knowledge of the mechanics of sensors manipulators and the concept of mobility will help reduce these problems this book provides that knowledge with the aid of hundreds of sketches showing drive layouts and manipulator geometries and their work envelope it discusses what mobility really is and how to increase it without increasing the size of the robot and how the shape of the robot can have a dramatic effect on its performance interspersed throughout the book are unusual mechanisms and devices included to entice the reader to think outside the box it is my sincere hope that this book will decrease the time it takes to produce a working robot reduce the struggles and effort required to achieve that goal and therefore increase the likelihood that your project will be a success building designing and working with practical mobile robots requires knowledge in three major engineering fields mechanical electrical and software many books have been written on robots some focusing on the complete robot system others giving a cookbook approach allowing a novice to take segments of chapters and put together xi copyright © 2003 by the mcgraw-hill companies inc click here for terms of use.[close]
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xii introduction a unique robot while there are books describing the electric circuits used in robots and books that teach the software and control code for robots there are few that are focused entirely on the mechanisms and mechanical devices used in mobile robots this book intends to fill the gap in the literature of mobile robots by containing in a single reference complete graphically presented information on the mechanics of a mobile robot it is written in laymen s language and filled with sketches so novices and those not trained in mechanical engineering can acquire some understanding of this interesting field it also includes clever schemes and mechanisms that mid-level mechanical engineers should find new and useful since mobile robots are being called on to perform more and more complex and practical tasks and many are now carrying one or even two manipulators this book has a section on manipulators and grippers for mobile robots it shows why a manipulator used on a robot is different in several ways from a manipulator used in industry autonomous robots place special demands on their mobility system because of the unstructured and highly varied environment the robot might drive through and the fact that even the best sensors are poor in comparison to a human s ability to see feel and balance this means the mobility system of a robot that relies on those sensors will have much less information about the environment and will encounter obstacles that it must deal with on its own in many cases the microprocessor controlling the robot will only be telling the mobility system go over there without regard to what lays directly in that path this forces the mobility system to be able to handle anything that comes along in contrast a human driver has very acute sensors eyes for seeing things and ranging distances force sensors to sense acceleration and balance to sense levelness a human expects certain things of an automobile s car truck jeep humvee etc mobility system wheels suspension and steering and uses those many and powerful sensors to guide that mobility system s efforts to traverse difficult terrain the robot s mobility system must be passively very capable the car s mobility system must feel right to a human for these reasons mobility systems on mobile robots can be both simpler and more complex than those found in automobiles for example the ackerman steering system in automobiles is not actually suited for high mobility it feels right to a human and it is well suited to higher speed travel but a robot doesn t care about feeling right not yet at least the best mobility system for a robot to have is one that effectively accomplishes the required task without regard to how well a human could use it.[close]
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introduction xiii there are a few terms specific to mobile robots that must be defined to avoid confusion first the term robot itself has unfortunately come to have at least three different meanings in this book the word robot means an autonomous or semi-autonomous mobile land vehicle that may or may not have a manipulator or other device for affecting its environment colin angle ceo of irobot corp defines a robot as a mobile thing with sensors that looks at those sensors and decides on its own what actions to take in the manufacturing industry however the word robot means a reprogrammable stationary manipulator with few if any sensors commonly found in large industrial manufacturing plants the third common meaning of robot is a teleoperated vehicle similar to but more sophisticated than a radio controlled toy car or truck this form of robot usually has a microprocessor on it to aid in controlling the vehicle itself perform some autonomous or automatic tasks and aid in controlling the manipulator if one is onboard this book mainly uses the first meaning of robot and focuses on things useful to making robots but it also includes several references to mechanisms useful to both of the other types of robots robot and mobile robot are used interchangeably throughout the book autonomous in this book means acting completely independent of any human input therefore autonomous robot means a self-controlled selfpowered mobile vehicle that makes its own decisions based on inputs from sensors there are very few truly autonomous robots and no known autonomous robots with manipulators on them whose manipulators are also autonomous the more common form of mobile robot today is semiautonomous where the robot has some sensors and acts partially on its own but there is always a human in the control loop through a radio link or tether another name for this type of control structure is telerobotic as opposed to a teleoperated robot where there are no or very few sensors on the vehicle that it uses to make decisions specific vehicles in this book that do not use sensors to make decisions are labeled telerobotic or teleoperated to differentiate them from autonomous robots it is important to note that the mechanisms and mechanical devices that are shown in this book can be applied in their appropriate category to almost any vehicle or manipulator whether autonomous or not another word which gets a lot of use in the robot world is mobility mobility is defined in this book as a drive system s ability to deal with the effects of heat and ice ground cover slopes or staircases and to negotiate obstacles chapter nine focuses entirely on comparing drive systems mobility based on a wide range of common obstacles found in[close]
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xiv introduction outdoor and indoor environments some of which can be any size like rocks others that cannot like stair cases i intentionally left out the whole world of hydraulics while hydraulic power can be the answer when very compact actuators or high power density motors are required it is potentially more dangerous and definitely messier to work with than electrically powered devices it is also much less efficient a real problem for battery powered robots there are many texts on hydraulic power and its uses if hydraulics is being considered in a design the reader is referred to industrial fluid power 4 volumes 3rd ed published by womack education publications the designer has powerful tools to aid in the design process beyond the many tricks mechanical devices and techniques shown in this book these tools include 3d design tools like solidworks and pro-engineer and also new ways to produce prototypes of the mechanisms themselves this is commonly called rapid prototyping rp new processes expand choices for rapid prototyping new concepts in rapid prototyping rp have made it possible to build many different kinds of 3d prototype models faster and cheaper than by traditional methods the 3d models are fashioned automatically from such materials as plastic or paper and they can be full size or scaleddown versions of larger objects rapid-prototyping techniques make use of computer programs derived from computer-aided design cad drawings of the object the completed models like those made by machines and manual wood carving make it easier for people to visualize a new or redesigned product they can be passed around a conference table and will be especially valuable during discussions among product design team members manufacturing managers prospective suppliers and customers at least nine different rp techniques are now available commercially and others are still in the development stage rapid prototyping models can be made by the owners of proprietary equipment or the work can be contracted out to various rp centers some of which are owned by the rp equipment manufacturers the selection of the most appropriate rp method for any given modeling application usually depends on the urgency of the design project the relative costs of each rp process and[close]
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