Fabrication of Automatic Guided Vehicle


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Automatic Guided vehicle (AGV) is a part of flexible manufacturing system. Now a days large manufacturing industries use the transportation systems foe various transportation purposes. various types of AGVs are available. Manufacturing and installation of this system is a tough task. The vehicle is designed according to the need and type of transportation, material to be transformed etc.

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Fabrication of Automatic Guided Vehicle

  2. 2. AXIS COLLEGE OF ENGINEERING & TECHNOLOGYP.O.MURIKKINGAL, THRISSURDEPARTMENT OF MECHANICAL ENGINEERINGCERTIFICATEThis is to certify that this Project Report TitledFABRICATION OF AUTOMATIC GUIDED VEHICLEwas carried out by the sixth semester students of Mechanical engineering inpartial fulfilment of the requirement for the award of Bachelor in Technology inmechanical engineering Under University of Calicut during the year 2012-2013,ofAxis College of Engineering & Technology, ThrissurAJITH ARAVIND, JESBIN JOHNSON, VINOD.K.J,VISHNU.T.SAJEEVANare members of the batchProject GuideJoffin Jose P S.KrishnanunniProject Coordinator H.O.D Mechanical EnggPlace: ThrissurDate:
  3. 3. Fabrication of Automatic Guided VehicleviDepartment of Mechanical Engineering ACETACKNOWLEDGEMENTWe express our deep sense of gratitude and indebtedness to Asst Prof. S.Krishnanunni, Head,Department of Mechanical Engineering for his valuable advice, constant encouragement andconstructive criticism during the course of the project and also during the preparation of thismanuscript, We place on record the valuable suggestions and numerous constructivecomments rendered by Asst Prof. Joffin Jose.P, Lecturer, Department of MechanicalEngineering and for being our internal guide in the design and implementation of our project.We are highly indebted to the staff members of Mechanical Department, especiallyAsst.Professors Clint.K.S, Krishnakiran.T.T, Jineesh.V.V, Sankar Raj, Renjith for theirwholehearted support and co-operation.We also express our sincere thanks to all the classmates for their support and co-operation in completing the project work.Above all, we should express our supreme gratitude to almighty God.
  4. 4. Fabrication of Automatic Guided VehicleviiDepartment of Mechanical Engineering ACETABSTRACTThe Automatic Guided Vehicle refers a type of system that can be used in production as wellas in other industries etc. This system includes a battery operated remote sensing locomotive(carrier) on which a small lift is provided, specific path over which it moves, sensors forsensing the the obstructions on the path of the carrier. Also sensors for sensing exactpositions from where load wants to carry and to where.The remote sensing carrier moves using the electric power from the battery. It moveswith a low and constant speed on the prescribed path. The path has a specific color. Thebottom of the carrier have sensor which is always coupled with the path. From the remotestation we send only information for moving the carrier, not for steering it. The steering isdone by the path. The front side of carrier vehicle contains sensors for sensing theobstructions on the path.As it reaches the collecting station, its top floor lift to a small distance and lift thestand which contains the parts wants to assemble, supply. And the carrier moves through thepath and reaches the supply station. The sensor provided on the carrier detected the stationand unload the stand contains assembly parts at that station. And move to collecting stationsagain. Continues working cycles for making this project a reality.
  5. 5. Fabrication of Automatic Guided VehicleviiiDepartment of Mechanical Engineering ACETTABLE OF CONTENTCHAPTER TITLE PAGECHAPTER I: INTRODUCTION1.1 Automatic Guided Vehicle 11.2 Background 31.3 Problem Statement 31.4 Project and It’s Scope 51.5 Market Survey 6CHAPTER II: LITERATURE REVIEW 72.1 AGV Built Worldwide Used 102.2 Mobile Post Distribution System (MOPS) 112.3 The Parkshuttle AGVs of Amsterdam’s Schiphol Airport 122.4 Line Following Robot 132.5 The Kerwin’s Line Following Robot 13CHAPTER III: COMPONENTS SELECTION AND DESCRIPTION 143.1 Design Objectives 143.2 Design Considerations 153.3 Components of AGV 173.4 Mechanical Part 193.4.1 Chassis 193.4.2 Steering System 203.4.3 Lifting Mechanism 223.5 Electrical Components 243.5.1 DC Motor 243.5.2 Battery 253.6 Electronics Components 263.6.1 Microcontroller 263.6.2 Motor Driver 29
  6. 6. Fabrication of Automatic Guided VehicleixDepartment of Mechanical Engineering ACET3.6.3 Regulators 333.6.3.1 7805 Regulator 333.6.3.2 LM317 Regulator 343.6.4 IR Sensor 353.6.5 Magnetic Sensor 383.6.6 Display Unit 403.7 Software Components 423.8 Program Source Code 43CHAPTER IV: DEVELOPED PROTOTYPE 504.1 Structure 504.2 Sensors Positions 524.3 Flow Chart 544.4 Block Diagram 554.5 Circuit Diagram 564.6 Theoretical and Logical Calculations 584.7 Billing 61CHAPTER V: CONCLUSION 62REFERENCES 64
  7. 7. Fabrication of Automatic Guided VehiclexDepartment of Mechanical Engineering ACETLIST OF TABLESTable Number Title Page2.1 Line Following Methods 133.1 Technical Data for Chassis 193.2 Steering Specifications 213.3 Motor Specifications 243.4 Battery Specifications 253.5 Specifications of ATmega 328 273.6 Important Connections 273.7 Technical Specifications of L293D 323.8 Maximum Rating of 7805 333.9 Technical Specifications of 7805 343.10 Technical Specifications of LM 317 343.11 Technical Specifications of IR Pair 373.12 Technical Specifications of Magnetic Sensors 393.13 Technical Specifications of Display Unit 403.14 Pin Configuration 404.1 Billing Table 61LIST OF FIGURESFigure Number Title Page2.1 The Mobile Post System 112.2 The Parkshuttle AGV’s of Amsterdam 122.3 The Kerwin’s Line Following Robot 133.1 Chassis of AGV 193.2 Differential Steering 203.3 Small Radius Turning 213.4 Lifting Using Threaded Shaft 223.5 Structure of Lift 233.6 DC Motor with Gearbox 243.7 Battery 253.8 ATmega 328 Microcontroller 28
  8. 8. Fabrication of Automatic Guided VehiclexiDepartment of Mechanical Engineering ACETFigure Number Title Page3.9 Motor Driver (L293D) 293.10 L293D Connected with Two Motors 303.11 L293D Connected with One Motor 303.12 Circuit Connection of Driving Motor 313.13 Connection of Lifting Motor 313.14 PWM 323.15 7805 Regulator 333.16 LM 317 Circuit 343.17 IR for Path Detection 353.18 IR Pair Circuit 363.19 Magnetic Sensor 393.20 Application Circuit of Display Unit 414.1 Front View of AGV 504.2 Top View of AGV 514.3 IR Sensor Positions of AGV 524.4 Magnetic Sensor Positions 534.5 Flow Chart 544.6 Block Diagram 554.7 Circuit Diagram 564.8 Fully Developed Prototype 57
  9. 9. Fabrication of Automatic Guided Vehicle1Department of Mechanical Engineering ACETCHAPTER IINTRODUCTION1.1 AUTOMATED GUIDED VEHICLEAn automated guided vehicle or automatic guided vehicle (AGV) is a mobile robot thatfollows markers or wires in the floor, or uses vision or lasers. They are most often used inindustrial applications to move materials around a manufacturing facility or a warehouseAutomated guided vehicles increase efficiency and reduce costs by helping toautomate a manufacturing facility or warehouse. The AGV can tow objects behind them intrailers to which they can autonomously attach. The trailers can be used to move rawmaterials or finished product. The AGV can also store objects on a bed. The objects can beplaced on a set of conveyor and then pushed off by reversing them. Some AGVs use forkliftsto lift objects for storage. AGVs are employed in nearly every industry, including, pulp,paper, metals, newspaper, and general manufacturing. Transporting materials such as food,linen or medicine in hospitals is also done.An AGV can also be called a laser guided vehicle (LGV) or self-guided vehicle(SGV). Lower cost versions of AGVs are often called Automated Guided Carts (AGCs) andare usually guided by specific lines magnetic tape. AGCs are available in a variety of modelsand can be used to move products on an assembly line, transport goods throughout a plant orwarehouse, and deliver loads to and from stretch wrappers and roller conveyors.AGVapplications are seemingly endless as capacities can range from just a few kgs to hundreds oftons. The Aim of the project is to design and fabricate such a AGVThere are many definitions of AGVs, different according to points of view.Wikipedia, the free encyclopedia, defines AGVs as:“A robot that been used highly in industrial applications to move materials from point topoint”
  10. 10. Fabrication of Automatic Guided Vehicle2Department of Mechanical Engineering ACETThe American Society of Safety Engineers (ASSE) defined AGVs as:a. Machines without drivers that can move along pre-programmed routes, or use sensory andnavigation devices to find their own way around.b. Vehicles that are equipped with automatic guidance systems and are capable of followingprescribed paths. Or Driverless vehicles that are programmed to follow guide path
  11. 11. Fabrication of Automatic Guided Vehicle3Department of Mechanical Engineering ACET1.2 BACKGROUNDThe creations of Automated Guided Vehicle (AGV) have been around since the 1950’s andthe technology was first developed by Barret Electronics from Grand Rapids, Michigan. Itwas then developed by the Europeans in the 1970’s and nowadays AGVs can be found in anycountries. One of the first AGVs was a towing vehicle that pulled a series of trailers betweentwo points, and today’s there are many task given to AGVs and they also have their ownname and potentials.Considering the full potentials and advantages of the Automated Guided Vehicle(AGV) in our livings, it is valuable to do this project, as it also will be the first step towardsthe creation of more intelligent technology or system. The simplest AGV model may use justa sensor to provide its navigation and can be the complex one with more sensors and advancesystems to do the task. They can work or do the task everywhere needed but the safety for theAGV as well as the people and environment surround it must be provided.The AGVs is just the same as mobile robot, which can moves from one place to anotherto do their task, but mostly the mobile robot is used for difficult task with dangerousenvironment such as bomb defusing. Furthermore, the mobile robot can be categorized intowheeled, tracked, or legged robot. Although the AGVs may not be glamorous of robots, buttheir work, which usually menial, are often be essential to the smooth running of factories,offices, hospitals, and even houses. They can work without any complaint around manyworkplaces all over the world.1.3 PROBLEM STATEMENTThere are many reasons which yield to the creation of Automated Guided Vehicle (AGV)around the world. Mostly the reason is to overcome the logistic problems that often occurredin the workplaces and to make improvement to the facilities provided in the workplaces.Usually the AGVs are implemented in factories, hospitals, offices, houses, and even can befound anywhere outdoors without the people surround realized it.
  12. 12. Fabrication of Automatic Guided Vehicle4Department of Mechanical Engineering ACETIn the industries or factories, the AGVs can ease the physical strain on human workersby performing tiring tasks, such as lifting and carrying heavy materials, more efficiently withno signs of fatigue creeping in. They can carry far more than human workers, and theirmovements can be tracked electronically at all times. Their movements can be timed to feedor collect products or materials from the work cells in the factories.Besides that, in the hospitals thousands of staff spends a portion of their day movingmedical supplies, bedding, medicines and other equipment around large hospitals. By usingthe AGVs, the strain on the workers can be ease as well as the hospital’s system would bemore smart and systematic without any bad complaint from the patients and people. AGVsalso capable of both cutting cost and releasing more staff hours to tend and care for patients.Therefore it is very significant that the valuable knowledge on AGV construction isstudied and be further implemented from the result of this project. It is due to its advantagesto our own living and technology.We have pleasure in introducing our project AGV, which is equipped bymicrocontroller, motor driving mechanism, lift mechanism and battery. The power stored inthe battery is used to drive the DC motor that causes the movement as well as lifting power toAGV. Battery assembled on the AGV is easily replaceable and detachable, used forrecharging the battery, while the AGV is under roof.
  13. 13. Fabrication of Automatic Guided Vehicle5Department of Mechanical Engineering ACET1.4 PROJECT AND ITS SCOPEThe objective and scope of this project is to create an AGV model that can follow a trail ofline on a flat surface horizontally. This AGV model is using microcontroller to control allnavigation and lifting functions during its operation. In other words, the microcontroller actsjust like the brain for the model that controls all operation of the system.The model is a three-wheeled mobile robot that has the ability to follow line on floor.There are three wheels including two driving wheels controlled by two motors and a freewheel in front that is able to rotate 360°. With three wheels, both driving wheels are alwaysin contact with the surface, because of the robot’s steering relies on both its driven wheelsbeing in contact with the surface at all times.This project consists of four main stages, which are theoretical design, mechanicalfabrication, electronic hardware design and as well as algorithm design in assembly language.The matter to be considered is how the robot can follow the trail of line continuously. It isalso important to choose the most suitable microcontroller, actuators, and sensors to achievethe project objectives..
  14. 14. Fabrication of Automatic Guided Vehicle6Department of Mechanical Engineering ACET1.5 MARKET SURVEYA market survey is an important requirement for initiating any successful business. Theobjective of a market survey is to collect information on various aspects of the business. Thissurvey is a tool through which we can minimize risk. After the market survey, the resultsmust be analyzed in order to finalize a business plan.We are implementing automatic guided vehicle, which replaces the normaltransporting methods. So that we wants to consider all the sections related to this works suchas problems arising while installing. So we conducted a market survey by personnel interviewtechniques was used with the measure emphasis on personal interview method. Interviewswere conducted through the structure questionnaire, Also we go through people who work inlarge industries such as production plant, supply station etc.The following questions are mainly taken for questionnaire:Area of applications? i.e. inside/outside/bothTypes surface of flooring?Weights of loads max?Distance to transportation?From the data which we got from the market survey we are well know about thethings what the market needed, and what modifications should be taken to the system. Andwe analysis the data and make objectives want to goal.
  15. 15. Fabrication of Automatic Guided Vehicle7Department of Mechanical Engineering ACETCHAPTER IILITERATURE REVIEWAutomatic Guided Vehicles (AGVs) have played a vital role in moving material and productfor more than 50 years. The first AGV system was built and introduced in 1953. It was amodified towing tractor that was used to pull a trailer and follow an overhead wire in agrocery warehouse. By the late 1950s and early 1960s, towing AGVs were in operation inmany types of factories and warehouses.The first big development for the AGV industry was the introduction of a unit loadvehicle in the mid 1970s. This unit load AGVs gained widespread acceptance in the materialhandling marketplace because of their ability to serve several functions; a work platform, atransportation device and a link in the control and information system for the factory.Since then, AGVs have evolved into complex material handling transport vehiclesranging from mail handling AGVs to highly automated automatic trailer loading AGVs usinglaser and natural target navigation technologies. In fact the improvement of AGVs over thelast decade is deeply indebted to development of Scheduling, Algorithm and Steeringmethods. The problem of scheduling of AGVs and the other supporting equipments has beenextensively studied by Basnet and Mize and Rachamadugu and Stecke currently providingthe most up-to-date and comprehensive reviews in this area.Han and McGinnis have developed a real time algorithm in which material handlingtransporters are considered. Schriber and Stecke have shown how the additional considerationof the material handling system and limited buffers degrades the system performance.Sabuncuoglu and Hommertzheim have highlighted the importance of material handling andthey compared several AGV dispatching rules. They have also shown how the buffer capacitycan affect the performance of the system. Flexibility, which is a distinguishing feature ofFMSs, has received an extensive amount of attention. Routing flexibility (i.e., alternativemachines and processing routes) has been considered by Wilhelm and Shin, Chen and Chung,and Khoshnevis and Chen . These studies have indicated that dynamic routing (i.e., a pathdetermined dynamically during schedule generation) performs better than a preplannedrouting.
  16. 16. Fabrication of Automatic Guided Vehicle8Department of Mechanical Engineering ACETRachamadugu et al. Have proposed a quantitative measure of sequence flexibility andhave shown that perfect sequence Flexibility improves system performance. Similarobservations have been made by Lin and Solberg. In most work to date, tools, pallets/fixturesand their availability are not modeled adequately. A static allocation of tools is usuallyassumed in these studies.However, some researchers have considered a limited tool magazine capacity and thechanging of tools from central tool storage. One purpose of this thesis is to develop analgorithm that can be used to investigate the research issues discussed above. This algorithmshould not only consider the major elements of FMSs but also generate high qualityschedules in a reasonable amount of time. In this thesis, the basic structure and characteristicsof such an algorithm is described.Kim et al. Proposed a deadlock detection and prevention algorithms for AGVs. It wasassumed that vehicles reserve grid blocks in advance to prevent collisions and deadlocksamong AGVs. A graphic representation method, called the "reservation graph," was proposedto express a reservation schedule in such a form that the possibility of a deadlock can beeasily detected. A method to detect possible deadlocks by using the reservation graph wassuggested.Maxwell and Muckstadt first introduced the problem of AGV flow system design.While their main concern is vehicle routing, they also address material flow path and stationlocation design issues. The flow network they used, known as conventional configuration, iscomposed of unidirectional arcs. Gaskin and Tanchoco developed the first integerprogramming model for material flow path design. Given a fixed network of aisles and fixedpickup and delivery stations, the model assigns direction to arcs to minimize the total tripdistances of loaded vehicles. Goetz and Egbelu developed an alternative model, where thestation locations no longer are fixed but restricted to the nodes on the boundary of the cells.Sun and Tchernev provide a comprehensive review on the models developed for conventionalconfiguration.Afentakis states the advantages of the loop layout as simplicity and efficiency,lowinitial and expansion costs, and product and processing flexibility. Loop layout has beenstudied by many researchers including Bartholdi and Platzman , Sharp and Liu ,Kouvelis and
  17. 17. Fabrication of Automatic Guided Vehicle9Department of Mechanical Engineering ACETKim , Egbelu , Banerjee and Zhou , and Chang and Egbelu. Bozer and Srinivasan initiate theconcept of tandem configuration as a set of no overlapping, bidirectional loops, each with asingle vehicle.Another problem in steering issues is to schedule several AGVs in a non-conflictingmanner which is a complicated real-time problem, especially when the AGV system is bi-directional. In fact, many conflicting situations may arise such as head-on and catching-upconflicts when the AGVs or the guide-paths are bidirectional and if no efficient control policyis used to prevent them. Several conflict-free routing strategies have been proposed and canbe classified into two categories: Predictive methods: Aim to find an optimal path for AGVs. The conflicts arepredicted off-line, and an AGV’s route is planned to avoid collisions and deadlocks. Reactive methods: the AGVs are not planned and the decisions are taken in a real-time manner according to the system state.These methods are based on a zone division of the guide-path and consider them asnon sharable resources. Predictive methods give good performance, but are not very robustsince they do not take into account real time problems. However, reactive methods are veryrobust but the resulting performances can be poor because the decisions are taken byconsidering a very short-term time horizon. In this report due to specification of the wholeplan (presence of only one AGV) a kind of predictive method is proposed.In early 1990s Fuzzy logic came through to control and manipulate whole of thematerial flow in manufacturing floors. The main indication of employing this system onAGVs was the ability of controlling multiple AGV in a same time without collision.However,only simulation results are presented. Senoo et al used experimental results of a threewheeled mobile robot to discuss the stability of a fuzzy controller. It is also stated that fuzzycontrol was implemented in order to achieve reduction of steer energy, while maintainingbetter steer angle when compared with PI control.Fuzzy logic has found useful applications in control among other areas. One usefulcharacteristic of a fuzzy controller is its applicability to systems with model uncertaintyand/or unknown models. Another useful characteristic of a fuzzy logic controller is that itprovides a framework for the incorporation of domain knowledge in terms of heuristic rules.
  18. 18. Fabrication of Automatic Guided Vehicle10Department of Mechanical Engineering ACETWuwei et al. They presented the new navigation method for AGV with fuzzy neural networkcontroller when in the presence of obstacles. Their AGV can avoid the dynamic and staticobstacle and reach the target safely and reliably.Wu et al. used fuzzy logic control and artificial potential field (APF) for AGVnavigation. The APF method is used to calculate the repulsive force between the vehicle andthe closest obstacle and the attractive force generated by the goal. A fuzzy logic controller isused to modify the direction of the AGV in a way to avoid the obstacle. Lin and Wangproposed a fuzzy logic controller for collision avoidance for AGV.They combined fuzzy logic with crisp reasoning to guide an AGV to get out of trapsince memories of path and crisp sequence flows are handled by non-fuzzy processing. Theirdesigned AGV was able to avoid collision with unknown obstacle. Alves and Junior used astep motor to turn the direction of the ultra-sonic sensors, so that each sensor can substitutetwo or more sensors in mobile robot navigation. Perhaps Sugeno has done one of thepioneering researches in mobile robot navigation using fuzzy logic control. The fuzzy controlrules, which he defines for the controller, were derived by modeling an expert driving action.He made a computer model of a car in microcomputer to find fuzzy rules. The speed of thedesigned car was constant; then, the control input to the car is only the angle of the steeringangleMehdi Yahyaei has design a AGV using fuzzy logic system and a rotational ultrasonic sensor to steer the AGV to avoid collisions and obstacles. He also employed aprogrammable logic control (PLC) as the processor which makes the AGV to be ultimately fitto the industrial environments.2.1 AUTOMATED GUIDED VEHICLE BUILT WORLDWIDESome of the Automated Guided Vehicles (AGVs) that are well known are discussedin brief.
  19. 19. Fabrication of Automatic Guided Vehicle11Department of Mechanical Engineering ACET2.2 MOBILE POST DISTRIBUTION SYSTEM (MOPS)MoPS or Mobile Post Distribution System (Tschichold, Vestli, Schweitzer, 1999) is aresearch AGV developed at the Institute of Robotics in Zurich, Switzerland. It is used totransport mail around the Swiss Federal Institute of Technology in Zurich. MoPS is poweredup by rechargeable batteries which give it a 4-hour active life, weighs around 90kg and cancarry up to 50 kg of postal payload. It is also capable of hot-swapping its own batteries pack,thus ensuring 24h availability.The MOPS provide services of picking up boxes with incoming mail at the groundfloor of the five floor building, which is sorted by human first, delivering them to thesecretaries offices, subsequently bringing back the outgoing mail to the ground floor station.It is also capable of switching floors by sending an infrared signal to the building’s lifts. Asthe building is open to the public, protection against theft of the mail is provided bymotorized blinds over the pigeon-hole mail points, which can be opened by the robot and byauthorized staff.Fig 2.1 The Mobile Post System MOPS
  20. 20. Fabrication of Automatic Guided Vehicle12Department of Mechanical Engineering ACET2.3 PARKSHUTTLE AGVS OF AMSTERDAM’S SCHIPHOL AIRPORTFig 2.2 The ParkShuttle AGVs of Amsterdam’s Schiphol Airport.The ParkShuttle (FROG Navigation Systems) is an automatic navigating vehicle whichprovides transportation for passengers. It is a people mover system. There is no driveronboard, instead a computer and an electronic navigation system do the driving. ThisParkShuttle has a safety system of sensitive and intelligent sensors. The sensors scan the areain front of the vehicle and will decelerate or stop the vehicle when an unknown obstacle isdetected.An additional safety feature is provided by the bumper system that brings the vehicleto an immediate halt when it is impressed. In addition, the vehicle has emergency stopbuttons (both inside and outside) that can be operated by the passengers. The speed is limitedto 40 km/h obtain a good ride quality. 8 The ParkShuttle vehicle runs on four rubber tires.Traction is provided by an electric motor powered by a rechargeable battery. Up to 100 kmcan be covered on one battery-load. It has a capacity of 10 passengers, 6 seated and 4standees. It is easy to get into and out of the vehicle (wheelchair accessible) and providesgood all-round visibility. Inside the vehicle is a console on which the passengers can indicatetheir destination.Each vehicle is also fitted with an information display that announces the stop at which thevehicle has arrived. The maximum load is 800 kg. The maximum vehicle weight is monitoredby means of weight sensor.
  21. 21. Fabrication of Automatic Guided Vehicle13Department of Mechanical Engineering ACET2.4 LINE FOLLOWING ROBOTLine following robot is generally a wheeled mobile robot. The method of line followingvaried depending on the number of sensors available and the type of line to be followed.There are four methods identified including edge following, line search, line trap, and cross-over. These four methods are different in number of sensors that used and also the results thatwill be obtained are different. With only one light sensor, the robot will have to know wherethe line is, or spends time searching to find it. Whereas with two light sensors, the robot ispossible to remember which direction the line went. With more sensors, the result that will beobtained would be more excellent and the robot will be more intelligent.Table 2.1 Line Following MethodMethod CharacteristicsEdge following Stay on the edge of the lineLine search Stay on the lineLine trap Keep the line between the sensorsCross over Move back and forth over the line2.5 KERWIN’S LINE FOLLOWING ROBOTFig 2.3 The Kerwin’s line following robot using three matched IR transmit/receive pairsThe Kerwin’s line following robot (ranchbots) is a design with Futaba S-148 servomotors mounted to the bottom of the plexiglass. It has three wheels with the front wheel is theomni-directional wheel. The sensor system consists of an array of three matched IRtransmit/receive pairs mounted on a circuit board that can be raised or lowered to fine tunethe sensitivity. It uses the Atmel microcontroller as the controller part. The microcontrollertakes input from sensor array and drives the servo motors in response.
  22. 22. Fabrication of Automatic Guided Vehicle14Department of Mechanical Engineering ACETCHAPTER IIICOMPONENTS SELECTION & DESCRIPTION3.1 DESIGN OBJECTIVESIn nowadays AGV has a greater influence in the production field. Why we prefer this systemis mainly because of its accuracy to transport goods, avoiding accidents at industrial zone,decreasing production overall cost etc.In our project the important factor is that, we give an additional functions to AGV, i.e.we provide a lifting mechanism to take loads from station to station. The lift will actuate atthose particular stations using sensors. Also we provide a sensor which detects the objects inthe paths to avoid collision with those objects, by stopping the vehicle and moves after thewhen object leaves the path.
  23. 23. Fabrication of Automatic Guided Vehicle15Department of Mechanical Engineering ACET3.2 DESIGN CONSIDERATIONSIn design problems many decision variables arise. The impact of decisions on mutualinteractions and performance might be difficult to predict. It might be hard to decide on onething without considering other decision variables. At least the following tactical andoperational issues have to be addressed in designing an AGV system• Flow path layout• Traffic management: prediction and avoidance of collisions and deadlocks• Number and location of pick-up and delivery points• Vehicle requirements• Vehicle routing• Vehicle scheduling• Battery managementA flow path layout compromises the fixed guided paths on which vehicles can travelto the various pick-up and delivery points of loads. Traffic management is required to avoidcollisions and deadlock situations in which two or more vehicles are blocked completely. Toensure that loads are transported in time, sufficient vehicles should be available and the rightvehicle should be dispatched to the right load.This layout is usually represented by a directed network in which aisles intersectionsand pickup and delivery locations can be considered as nodes. The arcs represent the guidepath the AGVs can travel on. Directed arcs indicate the direction of travel of vehicles in thesystem. The layout of this flow path directly influences the performance of the system. In ourproject we just mark two stations only. One loading and one unloading station. The carriermoves in the loop which connects these two stations.In controlling and designing AGV systems the problem of prevention of AGVcollisions and deadlocks should be addressed. By attaching sensors on AGVs, physicalcollisions can be avoided. An AGV should have the ability to avoid obstacles and the abilityto return to its original path without any collisions. We had fabricated only one AGV. So thetraffic management has only less important in our case. But while using more than one carrierwe should take care about them.
  24. 24. Fabrication of Automatic Guided Vehicle16Department of Mechanical Engineering ACETTo determine an optimal AGV’s system, capable of meeting all requirements, manyfactors have to be taken into account. Several of these factors are:• Number of units to be transported• Points in time at which units can be or need to be transported• Capacity of the vehicle• Speed of the vehicle• Costs of the system• Layout of the system and guide path• Traffic congestion• Vehicle dispatching strategies• Number and location of pick-up and delivery pointsIf AGVs use batteries, frequent battery changing might be required. McHaney (1995)presents an overview of AGV battery technology. The time required for replacing or chargingbatteries can impact the number of vehicles required. Simulation results from McHaney(1995) indicate a significant increase in the number of AGVs required while incorporatingbattery management issues in the simulation study compared to neglecting these issues in thestudies. Furthermore, the time required for charging batteries impacts throughput, congestionand costs.
  25. 25. Fabrication of Automatic Guided Vehicle17Department of Mechanical Engineering ACET3.3 COMPONENTS OF AGV1. MECHANICAL PARTSThe Mechanical components includes,1. Chassis2. Steering system3. Lift mechanismChassisAct as a frame for attaching other componentsCarry the load of other components and the payload.Act as sacrificial component to prevent damage of expensive payload in case ofaccidentsSteering SystemSteering system is for steering the AGV. The two individual motors are directly attached withthe wheel for steeringLifting MechanismLifting mechanism is one of the main part of AGV, the lifting surface moves upward anddownward at specified stations. And carry the load during load transfer.
  26. 26. Fabrication of Automatic Guided Vehicle18Department of Mechanical Engineering ACET2. ELECTRICAL COMPONENTSElectrical components include the motor and the power supply unit for the motor, sensoringunit3. ELECTRONIC COMPONENTSElectronic components provide sensing, logical decision and control of the vehicle. Itincludes microcontroller, which is the brain of the vehicle for the decision logic, the motordriver as both sensing and control of motor, regulator ICs, LCD Display unit, sensors forsensing the path, position of loading and unloading stations, detect object in the path etc.4. SOFTWARE COMPONENTSComputer is used for making and implementing program for the microcontroller, usingembedded computer programming language. For this project we use Arduino Unomicrocontroller board based on the ATmega328 .The Arduino Uno can be programmed withthe Arduino software.
  27. 27. Fabrication of Automatic Guided Vehicle19Department of Mechanical Engineering ACET3.4 MECHANICAL PART3.4.1 CHASSISThe chassis is fabricated from Acrylic sheet. This is done for ease of fabrication, and toreduce the overall weight. It was designed in Catia; part of fabrication was outsourced due tounavailability of precision cutting tools. The chassis was designed to take a static load of 3kg.The Top part of chassis has lots of drilled holes which serves as holes for boltingother parts and reduce the weight of the chassis. The Holes are arranged in a zigzag lineararrangement so that the decrease in strength of chassis is not considerable.The flange which holds the motor was designed using Aluminium and is bolted to thechassis. So that the driving motors can easily accommodate below the chassis. The chassisincorporates hole for attaching front globe wheel, and also for attaching the lift structureFig 3.1 Chassis of AGVTable 3.1 Technical Data of ChassisFeatures DataLength 300mmBreadth 160mmHeight 62mmMaterial Colored Acrylic sheet, AluminumMaximum loadMounting Holes 14×3mm ø Holes for general mounts2×8mm ø Holes for motor1×10mm ø Hole for switch
  28. 28. Fabrication of Automatic Guided Vehicle20Department of Mechanical Engineering ACET3.4.2 STEERING SYSTEMThe steering system used in the model is of differential type. A differential wheeled vehicle isa vehicle whose movement is based on two separately driven wheels placed on either side ofthe body. It can thus change its direction by varying the relative rate of rotation of its wheelsand hence does not require an additional steering motion. It allows the turning center to be onthe vehicle body thus the ability to rotate on the pointFig3.2 Differential SteeringIf both wheels rotate at the same speed and in the same direction, the robot will movein a straight line.
  29. 29. Fabrication of Automatic Guided Vehicle21Department of Mechanical Engineering ACETFig 3.3 Small radius turningIf one of the wheels is stopped, while the other continues to rotate, the robot will pivotaround a point centred approximately at the mid-point of the stopped wheel.Table 3.2 Steering SpecificationsFeature DataWheel Base 180mmWheel Diameter 70mmTrack Distance 170mmMaterial Rubber and plasticTurning radius 190mm
  30. 30. Fabrication of Automatic Guided Vehicle22Department of Mechanical Engineering ACET3.4.3 LIFTING MECHANISMThe lift is the main component of this AGV. The lift takes and gives loads at specific stations.The vehicle under stands the stations using sensors. Lift is attached in the front portion of thechassis. The power for lift is transmitted from a motor using a threaded shaft.The lift consists of mainly two plates. One is centrally drilled and tapped. Secondplate is attached with the lower one, using bolts, at a distance. The shaft of the motor drilledaxially and made internal threads using tap. Both the plates moves in between two guideways. The threaded shaft is passed through the centrally tapped hole of lower plate.During the rotation of shaft the lower plate moves up or down. And the upper platemoves according to it. The time for the rotation is limited for few seconds. It can be adjustedby making changes in the microcontroller program. A magnet is attached above the upperplate, which helps to hold the items to be lift, which have magnetic behavior.Fig 3.4 Lifting using threaded shaft
  31. 31. Fabrication of Automatic Guided Vehicle23Department of Mechanical Engineering ACET4312In order to reduce the overall cost and weight of the AGV, we used acrylic sheets forthe manufacturing of lifting surfaces, Aluminum C channels for the guide ways in betweenthe plates moves are used for the fabrication.Fig 3.5 Structure of lift1. Guide ways2. Threaded shaft3. Lower plate4. Upper plate
  32. 32. Fabrication of Automatic Guided Vehicle24Department of Mechanical Engineering ACET3.5 ELECTRICAL COMPONENTS3.5.1 DC MOTOR100 RPM DC Motor with Gearbox generally used for robotic application are used for thedriving mechanism, steering mechanism and lifting mechanism. We can adjust it to desiredRPM using gear box. Very easy to use. It is excellent for line tracking robotic application.Fig 3.6 DC Motor with Gear boxTable 3.3 Motor SpecificationsFeature DataSupply voltage 12V DCSpeed 100 RPM with gear boxShaft Diameter 6mmWeight 125gmTorque 12KgcmNo-load current 60mA(Max)Load current 250ma(Max)
  33. 33. Fabrication of Automatic Guided Vehicle25Department of Mechanical Engineering ACET3.5.2 BATTERYThe power required for the entire working process is given by a Rechargeable valve regulatedLead-Acid battery. The power from the battery is split it into two and one part is given tomicrocontroller, display unit, driving unit and other part is given to lifting motor.Fig 3.7 BatteryTable 3.4 Battery SpecificationFeatures DataSpeed 100rpmVoltage 12V DCTorque 12Kg-cmNo load current 60mALoad current 250mA
  34. 34. Fabrication of Automatic Guided Vehicle26Department of Mechanical Engineering ACET3.6 ELECTRONICS COMPONENTS3.6.1 MICROCONTROLLERA microcontroller (µC, uC or MCU) is a small computer on a single integrated circuitcontaining a processor core, memory, and programmable input/output peripherals.Microcontrollers are designed for embedded applications, in contrast to the microprocessorsused in personal computers or other general purpose applications.We use ATmega 328 in our AGV.The Atmel®AVR® ATmega 328 is a low-powerCMOS 8-bit microcontroller based on the AVR RISC architecture. By executing powerfulinstructions in a single clock cycle, the ATmega8 achieves throughputs approaching 1MIPSper MHz, allowing the system designed to optimize power consumption versus processingspeed.The reasons for using ATmega 328 are:Low costEasy to programHigh-performance, Low-powerFully Static OperationHigh Endurance Non-volatile Memory segmentsPower-on Reset and Programmable Brown-out DetectionInternal Calibrated RC OscillatorExternal and Internal Interrupt SourcesHigh stress valueFive Sleep Modes: Idle, ADC Noise Reduction, Power-save, Power-down, andStandbyI/O and Packages23 Programmable I/O Lines28-lead PDIP, 32-lead TQFP, and 32-pad QFN/MLFOperating Voltages2.7V - 5.5v to 4.5V - 5.5V
  35. 35. Fabrication of Automatic Guided Vehicle27Department of Mechanical Engineering ACETThe Microcontroller is programmed with the required program to accept the data fromthe sensing unit, interpret it, and give responses to the driving and lifting mechanism in verysmall time interval.Table 3.5 Specification of ATmega 328Type: 28Pin DIP PackageFlash 32K BytesI/O pins 23 PinsMinimum/Maximum Voltage: 1.8/5.5VMaximum current: 20mANumber of PORTS 4No of channels 6Bus width 10BitOscillation Speed 20MhzPWM 6Table 3.6 Important ConnectionsPIN Name Pin NoVcc 7GND 8,22XTAL1 9XTAL2 10RXD/PD0 2PB4 16PB5 19PB6 9PB7 10Reset 1Rxd 2Txd 3AVCC 20AREF 21
  36. 36. Fabrication of Automatic Guided Vehicle28Department of Mechanical Engineering ACETFig 3.8 ATmega 328 microcontroller
  37. 37. Fabrication of Automatic Guided Vehicle29Department of Mechanical Engineering ACET3.6.2 MOTOR DRIVERIt is an electronic circuit which enables a voltage to be applied across a load in eitherdirection. It allows a circuit full control over a standard electric DC motor. That is, with an H-bridge, a microcontroller, logic chip, or remote control can electronically command the motorto go forward, reverse, brake, and coast.A "double pole double throw" relay can generally achieve the same electricalfunctionality as an H-bridge, but an H-bridge would be preferable where a smaller physicalsize is needed, high speed switching, low driving voltage, or where the wearing out ofmechanical parts is undesirable. The term "H-bridge" is derived from the typical graphicalrepresentation of such a circuit, which is built with four switches, either solid-state (e.g.,L293/ L298) or mechanical (e.g., relays).In our AGV we use the driver IC L293d. There are two driver ICs are provided in thedesign, because three motor are in the AGV. One driver circuit is connected to the twomotors of driving mechanism. And second one is used for the motor which is incorporatedwith the lift.Fig 3.9 Motor Driver (L293D)
  38. 38. Fabrication of Automatic Guided Vehicle30Department of Mechanical Engineering ACETThe following figure shows the connection of the driving mechanism.Fig 3.10 L293D connected with two motorsTo simplify use as two bridges each pair of channels is equipped with an enable input.A separate supply input is provided for the logic, allowing operation at a lower voltage.This device is suitable for use in switching applications at frequencies up to 5 kHz.In the lifting section one motor is utilized. So the one side of the driver circuit is notconnected.Fig 3.11 L293D connected with one motor
  39. 39. Fabrication of Automatic Guided Vehicle31Department of Mechanical Engineering ACETIn the both end of a motor voltage is always 5v. So there no potential difference between thetwo terminals of the motor. Therefore there is no current flow between terminals, and motorwill not work. During the operation at one terminal the voltage becomes zero volts. And thusthe current flows through the motor and it works. We can rotate the motor in two directions.In the driving mechanism, in our design one direction of rotation of motor is needed.Because the AGV doesn’t wants to moves in reverse. But the connection is made in such away that both two motors rotate in opposite direction. i.e., the motor which rotates the rightwheel in clockwise direction and that of left wheel rotates in counter clockwise direction.But the lifting motor wants to rotate in the both directions. For the clock wise rotationlift move up and for counter clockwise it moves down. The movement of the lift surfacedepends on the internal thread of the lower plate also.Fig 3.12 Circuit connection of driving motorFig 3.13 Connection of lifting motor for clock wise and counter clock wise rotation
  40. 40. Fabrication of Automatic Guided Vehicle32Department of Mechanical Engineering ACETTo control motor speed we can use pulse width modulation (PWM), applied to the enablepins of L293d driver. PWM is the scheme in which the duty cycle of a square wave outputfrom the microcontroller is varied to provide a varying average DC output.Fig 3.14 PWMTable 3.7 Technical Specification of L293DSymbol Parameter DataVs Supply Voltage 36VVss Logic Supply Voltage 36VVi Input Voltage 7VVen Enable Voltage 7VIo Peak Output Current 1.2APtot Total Power Dissipation at Tpins=90ᵒc 4WTstg,Tj Storage and Junction Temperature -40 to 150ᵒc
  41. 41. Fabrication of Automatic Guided Vehicle33Department of Mechanical Engineering ACET3.6.3 REGULATORSMainly two types of voltage regulators are used in the design. One is variable and the next isnot. The non variable belongs to 78 series. And variable is LM series. The main supply is12V. But we need only 5V. It is made possible using these regulators3.6.3.1 7805 RegulatorIt is the one of the important electronic part. The motor, driving IC, microcontroller etc needonly 5V for their operations. Before the supply is given to these circuits it is given to the7805 voltage regulator. It reduces the voltage from 12V to 5V.Fig 3.15 7805 REGULATORThe main features of these regulators are:Internal Thermal Overload Protection.Internal Short Circuit Current Limiting.Output Current up to 1.5A.Satisfies IEC-65 Specification.Table 3.8 Maximum Ratings of 7805Characteristic Symbol RatingInput Voltage Vin 35VOperating JunctionTemperatureTj -40 to 150 ᵒcStorage Temperature Tstg -55 to 150 ᵒcMax. junction Temperature Tj(max) 150 ᵒc
  42. 42. Fabrication of Automatic Guided Vehicle34Department of Mechanical Engineering ACETTable 3.9 Technical Specifications of 7805ELECTRICAL CHARACTERISTICS (VIN=10V, IOUT=500mA, 0ᵒc≤ Tj≤ 125ᵒc)Characteristic DataOutput Voltage 4.8 to 5.2 VInput Regulation 100 mVOutput Noise Voltage 50 microVrmsRipple Rejection Ratio 78dBDrop Out Voltage 2.0V3.6.3.2 LM317 VARIABLE REGULATORThere are five variable regulators are used in our design. Its used for reduce thevoltage to the motor and to sensors. It will helps to reduce the speed of rotation of themotor and thus we can adjust the speed of the vehicle.Fig 3.16 LM317 circuitTable 3.10 Technical Specificationsof LM 317Parameter DataLine Regulation 0.01 %/VLoad Regulation 0.1%/VThermal Regulation 0.04%/WCurrent Limit 2.2ARipple Rejection Ratio 65dBLong term stability 0.3%RMS Output Noise 0.003%
  43. 43. Fabrication of Automatic Guided Vehicle35Department of Mechanical Engineering ACET3.6.4 INFRARED SENSORSIR Sensor is one of the important parts. Path detection and obstrucle detection is done withthe help of IR Sensors. There are five IR Sensors are in our AGV. Out of them four are usedfor the path detection and rest of one is used for obstrucle detection.IR sensor have a transmitter and a receiver port.The strength of signal reached at the receiver port after the reflection of light is usedto detect the path. Path is marked in the black background by white lines. Sensor detect thewhite line by the strength of IR wave. The reflected wave from white line has high strengththan that of from black. TSOP1730 are used in the design.Fig 3.17 IR for Path Detection
  44. 44. Fabrication of Automatic Guided Vehicle36Department of Mechanical Engineering ACETThe IR pair circuits are shown in the figure give below:Fig 3.18 IR pair Circuit
  45. 45. Fabrication of Automatic Guided Vehicle37Department of Mechanical Engineering ACETThe main features of this IR pair are:Photo detector and preamplifier in one packageInternal filter for PCM frequencyImproved shielding against electrical field disturbanceTTL and CMOS compatibilityOutput active lowLow power consumptionHigh immunity against ambient lightContinuous data transmission possible (up to 2400 bps)Suitable burst length 10 cycles/burstTable 3.11 Technical Specifications of IR pairCharacteristics DataSupply Voltage -0.3 to 6.0VOutput Voltage -0.3 to 6.0VJunction Temperature 100 ᵒcOperating Temperature -2.5 to 85ᵒcPower Consumption 50mWIrradiance 30W/m²Directivity ±45º
  46. 46. Fabrication of Automatic Guided Vehicle38Department of Mechanical Engineering ACET3.6.5 MAGNETIC SENSORMagnetic sensors or magnetic switches are electronic switches that close under the magneticfield. In this AGV there are two magnetic sensors. XEN-1210 is the sensor used in thisdesign.The XEN-1210is a CMOS linear magnetic field sensor with a very low offset. It usesXensors patented high performance spinning-current Hall-plate technology, a precisionamplifier and a sigma delta AD converter, and offers full digital control and communicationthrough a SPI serial bus. The device does not need calibration and in contrast to low-offsetAMR sensors does not use a set/reset method. It has no hysteresis and is indestructible byhigh magnetic fields. It does not need any external components and is truly a one-chipsolution.These sensors are used for the purpose of position detection. It is used for detect theloading and unloading station. The sensor is attached with the vehicle at two differentpositions. Magnets are placed in such a way that one sensor close when the vehicle comes tothe loading station. And when that switch close lift operates and moves up. After loading thevehicle moves along the path. When it reach the unloading station the next sensor close andlift operates to move down.The main features of this sensor areSingle axis magnetic measurementOne chip solution15nT resolutionWide magnetic field range (±63mT)No magnetic hysteresisLow voltage operation (2.5V to 3.3V)Single supply-40°C to 125°C Temperature Range
  47. 47. Fabrication of Automatic Guided Vehicle39Department of Mechanical Engineering ACETFig 3.19 Magnetic sensorIt’s a glass capsule, inside the tube there are two reed blades, which is connected to thevoltage terminal. Reed blades are placed over lapped, but not connected. There is a contactgap between the blades. And the tube is filled with inert gas.Table 3.12 Technical Specifications of Magnetic sensorsSpecifications DataVDD 3.3VField Range ±63mTResolution(24 bits) 7.5nT/LSBHysteresis 10nTNoise 55nT/Hz^½Temperature range -40 to 125 ºC
  48. 48. Fabrication of Automatic Guided Vehicle40Department of Mechanical Engineering ACET3.6.6 DISPLAY UNITIt’s just to display the inputs and outputs of the system. It mainly displays the inputs of pathsensing IR sensors and working of the vehicle. Inputs are displayed using numbers.JHD162A SERIES is the display unit used in the AGV.Characteristics:Char. Dots 5 x 8Display content 16 CHAR x 2ROWDriving mode 1/16dAvailable types:TN STN (yellow green)Reflective with El or Led BacklightEL/100VAC 400HZLED/4.2VDCTable 3.13 Technical Specifications of Display unitParameter DataSupply Voltage 5.0VInput High Voltage 2.2VOutput High Voltage 2.4VOperating Voltage 1.5mATable 3.14 Pin ConfigurationsPin Connection1 Vss2 Vcc3 VEE4 RS5 R/W6 E7 DB08 DB19 DB210 DB311 DB412 DB513 DB614 DB715 LED+16 LED-
  49. 49. Fabrication of Automatic Guided Vehicle41Department of Mechanical Engineering ACETFig 3.20 Application Circuit of display unit
  50. 50. Fabrication of Automatic Guided Vehicle42Department of Mechanical Engineering ACET3.7 SOFTWARE COMPONENTSWe use ATmega328 microcontroller in this AGV. The microcontroller is the brain of thevehicle. So the programming of the microcontroller has great imporantance in the working.Arduino software is used to program the microcontroller. Program is burned using specialmicrocontroller board. For this ATmega328 microcontroller Arduino Uno board is used.The Arduino Uno is a microcontroller board based on the ATmega328 . It has 14digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a16 MHz ceramic resonator, a USB connection, a power jack, an ICSP header, and a resetbutton. It contains everything needed to support the microcontroller; simply connect it to acomputer with a USB cable or power it with a AC-to-DC adapter or battery to get started.Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software. Its intended for artists, designers, hobbyists, and anyoneinterested in creating interactive objects or environments.The program is written in the Arduino software using special commands. The mainfeature of this software is that we can run the program before burning in to themicrocontroller. And we can check the function. It will helps to make changes in theprogram, in easy way.The program is written in such a way that when the vehicle is in on condition, the fourline detecting sensors works and detect the line. If the middle sensors close, the two drivingmotor rotates. If left sensors close right motor works, if right sensors close left motor works.If the object detector sensor closes, all the two motors stops whatever may be the linedetecting conditions.When the right magnetic switch closes the third motor rotates in clockwise, when leftswitch closes it rotates in anti clockwise direction. All the input signals for the line detectionand position detection are shown in the LCD display. Also the working status is shown in thedisplay
  51. 51. Fabrication of Automatic Guided Vehicle43Department of Mechanical Engineering ACET3.8 PROGRAM SOURCE CODE#include <LiquidCrystal.h>int a = 0;int b = 0;int c = 0;int d = 0;int e = 0;int f = 0;LiquidCrystal lcd(8, 9, 10, 11, 12, 13);void setup(){Serial.begin(9600);pinMode(A0, INPUT);pinMode(A1, INPUT);pinMode(A2, INPUT);pinMode(A3, INPUT);pinMode(A4, INPUT);pinMode(A5, INPUT);pinMode(7, OUTPUT);pinMode(6, OUTPUT);pinMode(5, OUTPUT);
  52. 52. Fabrication of Automatic Guided Vehicle44Department of Mechanical Engineering ACETpinMode(4, OUTPUT);pinMode(2, OUTPUT);pinMode(3, OUTPUT);lcd.begin(16, 2);lcd.clear();lcd.setCursor(0, 0);lcd.print("L F Robot");delay(1000);}void loop(){a = digitalRead(A5);b = digitalRead(A4);c = digitalRead(A3);d = digitalRead(A2);e = digitalRead(A1);f = digitalRead(A0);lcd.setCursor(0, 0);lcd.print("A:");lcd.setCursor(2, 0);lcd.print(a);lcd.setCursor(4, 0);lcd.print("B:");lcd.setCursor(6, 0);
  53. 53. Fabrication of Automatic Guided Vehicle45Department of Mechanical Engineering ACETlcd.print(b);lcd.setCursor(8, 0);lcd.print("C:");lcd.setCursor(10, 0);lcd.print(c);lcd.setCursor(12, 0);lcd.print("D:");lcd.setCursor(14, 0);lcd.print(d);delay(100);if((a==LOW && b==HIGH && c==HIGH && d==LOW) || (a==HIGH && b==LOW &&c==LOW && d==HIGH)){lcd.clear();lcd.setCursor(0, 1);lcd.print("Forward");Serial.print("Forwardt");digitalWrite(3, HIGH);digitalWrite(2, HIGH);digitalWrite(7, HIGH);digitalWrite(6, LOW );digitalWrite(5, HIGH);digitalWrite(4, LOW );delay(200);
  54. 54. Fabrication of Automatic Guided Vehicle46Department of Mechanical Engineering ACET}else if((a==LOW && b==LOW && c==HIGH && d== LOW ) || (a==HIGH &&b==HIGH && c==LOW && d== HIGH )){lcd.clear();lcd.setCursor(0, 1);lcd.print("Left");Serial.print("Leftt");digitalWrite(3, HIGH);digitalWrite(2, HIGH);digitalWrite(7, HIGH);digitalWrite(6, HIGH);digitalWrite(5, HIGH);digitalWrite(4, LOW );delay(200);}else if((a==LOW && b== HIGH && c==LOW && d==LOW) ||(a==HIGH && b==LOW&& c==HIGH && d==HIGH)){lcd.clear();lcd.setCursor(0, 1);lcd.print("Rihgt");Serial.print("Rihgtt");
  55. 55. Fabrication of Automatic Guided Vehicle47Department of Mechanical Engineering ACETdigitalWrite(3, HIGH);digitalWrite(2, HIGH);digitalWrite(7, HIGH);digitalWrite(6, LOW );digitalWrite(5, HIGH);digitalWrite(4, HIGH);delay(200);}else if((a==HIGH && b==HIGH && c==HIGH && d==HIGH )|| (a==LOW && b==LOW&& c==LOW && d==LOW) ){lcd.clear();lcd.setCursor(0, 1);lcd.print("Stop");Serial.print("Stopt");digitalWrite(3, HIGH);digitalWrite(2, HIGH);digitalWrite(7, HIGH);digitalWrite(6, HIGH);digitalWrite(5, HIGH);digitalWrite(4, HIGH);delay(200);}
  56. 56. Fabrication of Automatic Guided Vehicle48Department of Mechanical Engineering ACETif(f==HIGH){while(1){lcd.clear();lcd.setCursor(0, 1);lcd.print("arm up");digitalWrite(7, HIGH);digitalWrite(6, HIGH);digitalWrite(5, HIGH);digitalWrite(4, HIGH);digitalWrite(3, LOW);digitalWrite(2, HIGH);delay(18000);digitalWrite(7, HIGH);digitalWrite(6, LOW );digitalWrite(5, HIGH);digitalWrite(4, LOW );delay(200);break;}}if(e==HIGH)
  57. 57. Fabrication of Automatic Guided Vehicle49Department of Mechanical Engineering ACET{while(1){lcd.clear();lcd.setCursor(0, 1);lcd.print("arm down");digitalWrite(7, HIGH);digitalWrite(6, HIGH);digitalWrite(5, HIGH);digitalWrite(4, HIGH);digitalWrite(3, HIGH);digitalWrite(2, LOW);delay(18000);digitalWrite(7, HIGH);digitalWrite(6, LOW );digitalWrite(5, HIGH);digitalWrite(4, LOW );delay(200);break;}}delay(100);}
  58. 58. Fabrication of Automatic Guided Vehicle50Department of Mechanical Engineering ACETCHAPTER IVDEVELOPED PROTOTYPE4.1 STRUCTUREThe vehicle is designed in such a way that, have stability during loading and working. Thelifting parts are provided in the front position. It comes above the front globe tyre. Theelectronic and electrical parts are situated the rest of surface. Motor for driving are providedin the rear region. Hence during dynamic loading the vehicle will be stable.The structure of the vehicle is shown in the figure,Fig 4.1 Front view of AGV
  59. 59. Fabrication of Automatic Guided Vehicle51Department of Mechanical Engineering ACETFig 4.2 Top view of AGV
  60. 60. Fabrication of Automatic Guided Vehicle52Department of Mechanical Engineering ACET4.2 SENSORS POSITIONSThe positions of sensors are important factor to detect the position. The sensors for detectingthe path are situated after the front wheel. But the obstruction detection sensor is placedbelow the chassis, and in front of the front tyre. There are four IR sensors used to detect thepath. They are along a line parallel to the breadth. And side sensors are placed at an equaldistances from middle sensors.The width of the white line is little more than the distance between two sensors. Allthe four sensors were give different movements during different combination. Thecombination means closing of IR sensors. According to it the working of the driving motorschange. Initially the AGV is placed above the line, in such a way that the two middle sensorcomes above the white line.During the straight path the middle sensors close, the two motors run in forwarddirection with equal speed. Thus the vehicle moves in the straight line. When two of the leftside close left motor stops and right works. Then the AGV takes a left turn depending uponthe curvature. And when two right side sensors close,right side motor stops and the leftworks. Thus the AGV takes a right turn.Fig 4.3 IR Sensors positions of AGV
  61. 61. Fabrication of Automatic Guided Vehicle53Department of Mechanical Engineering ACETThe design of path is very important for an AGV. The magnetic sensors are placed below thedriving motors. Two magnets are used to detect the loading and unloading station. There is aparticular distance between those sensors and the lift. The loading stand should be placedabout at that distance from the magnet. Lifting up sensor is placed below the right motor. Soone of the magnet is placed in the right side of the path. Lifting stand is placed about adistance from that magnet. The magnets are placed in such a way that any one of its polescomes to top. Only then the magnetic switch works.Fig 4.4 Magnetic sensors positions
  62. 62. Fabrication of Automatic Guided Vehicle54Department of Mechanical Engineering ACET4.3 FLOW CHARTFig 4.5 Flow chartDetectNot DetectOnOff
  63. 63. Fabrication of Automatic Guided Vehicle55Department of Mechanical Engineering ACET4.4 BLOCK DIAGRAMFig 4.6 Block DiagramBlock diagram is a diagram of a system, in which the principal parts or functions arerepresented by blocks connected by lines that show the relationships of the blocks. They areheavily used in the engineering world in hardware design, electronic design, software design,and process flow diagrams. In this diagram direction of all arrows are either from or to themicrocontroller.MICRO-CONTROLLERLCDMOTOR 1POWER SUPPLYMOTORDRIVERMOTOR 2MAGNETC REEDSENSORLINE DETECTORSENSORMOTORDRIVERMOTOR 3OBJECT DETECTORSENSOR
  64. 64. Fabrication of Automatic Guided Vehicle56Department of Mechanical Engineering ACET4.5 CIRCUIT DIAGRAMFig 4.7 Circuit Diagram
  65. 65. Fabrication of Automatic Guided Vehicle57Department of Mechanical Engineering ACETThe fully fabricated prototype of Automatic Guided Vehicle has possessed the intelligencessuch as following a particular line, loading and unloading at particular stations and collisionavoidance etc.Fig 4.8 Fully Developed Prototype
  66. 66. Fabrication of Automatic Guided Vehicle58Department of Mechanical Engineering ACET4.6 THEORETICAL AND LOGICAL CALCULATIONSTorque of DC motor used, T = 12Kg-cm= 1.1772 N-mSpeed of motor, N = 100 RPMAngular Velocity, ω = 2ΠN/60= (2*Π*100)/60= 10.47 rad/secPhysically Power is the rate of doing work. For linear motion, power is the product of forcemultiplied by the distance per unit time. In the case rotational motion, the analogouscalculation for power is the product of Torque multiplied by the rotational distance per unittimeRotational Power, P = T * ω= 1.1772*10.42=12.33 WNo. of motors available for driving mechanism = 2 motorsSo total power available for driving = 2* 12.33= 24.66 WThere is only one motor is used for the lifting purposes,So maximum power available at lifting mechanism = 12.33 W
  67. 67. Fabrication of Automatic Guided Vehicle59Department of Mechanical Engineering ACETWe have relation, v = r*ωWhere, v= Linear velocityR= Radiusω= Angular velocityDiameter of shaft, d= 0.6cmRadius of shaft, r= 0.3cm=0.3*10^ (-2)∴ Linear velocity, v = (0.3*10^ (-2)) * 10.47= 0.03141 m/s= 3.14 cm/sWeight of carrier = 1.495 KgWidth of line marking= 4.3cmFor Lifting section,Shaft Torque, Tsh = output/2ΠN= 1.1772/ (2Π*100)= 1.8735* 10^ (-3) N-mForce * Distance = TorqueDistance to be lifted, l= 5mmForce * (5*10^ (-3)) = 1.8735*10^ (-3)Force, F = 3.75 N
  68. 68. Fabrication of Automatic Guided Vehicle60Department of Mechanical Engineering ACETForce, F= Load * gAcceleration due to gravity, g= 9.81m/Load = 3.75/9.81= 0.383 Kg≈400 gms
  69. 69. Fabrication of Automatic Guided Vehicle61Department of Mechanical Engineering ACET4.7 BILLINGNO ITEM NO. ITEM COST/ITEM TOTALCOST,(R.S)1 DC Motor 3 200 6002 Micro Controller 1 350 3503 Driver IC 2 100 2004 LCD Display 1 350 3505 IR Sensors 5 175 8756 Magnetic Switch 2 80 1607 Acrylic Sheet 1 160 1608 Aluminum channel 1 30 309 Battery 1 400 40010 Fasteners 25 2511 Magnets 3 25 7512 Sticking Glues 2 30 6013 Electronic Components 25014 Arduino board 1 1350 1350Total 4885Table 4.1 Billing Table
  70. 70. Fabrication of Automatic Guided Vehicle62Department of Mechanical Engineering ACETCHAPTER VCONCLUSIONThe AGV is a productivity increasing feature in a factory. During the manufacturing of thisAGV we had found many of intelligence that can be given to it. We provide the basicfunctions like line following and collision avoiding. And the main function, transportation ofgoods from station to station. The followings are the main features of the prototype which wefabricated.1. Speed of delivery2. Adjustment of vehicle speed3. Flexibility of path4. Adaptive to changes in factory layouts5. Avoid collision with other objects6. Reduction in labour cost7. Reduction in running cost compared to conveyer systems8. Ability to add sensors to detect the payload conditions9. Ability to adjust the lifting time10. Continues cycle of working11. Conditions for line following can be change easilyAutomatic Guided Vehicle can be used in a wide variety of applications to transportmany different types of material including pallets, rolls, racks, carts, and containers. AGVsexcel in applications with the following characteristics: Repetitive movement of material over a distance Regular delivery of stable loads Medium throughput/volume When on time delivery is critical and late deliveries are causing inefficiencies Operation with at least two shifts Archive Systems Cross Docking Distribution High Density Storage
  71. 71. Fabrication of Automatic Guided Vehicle63Department of Mechanical Engineering ACET High Speed Sortation Material Flow and Transport Production and Manufacturing Delivery Systems Production and Manufacturing Support Systems Warehouse Management and Control Work-In-Process BuffersThe fabricated models have following advantages while comparing with the existingmodels of this kind. The analyzing of advantages helps to motivate the fabrication ofAGV in the manufacturing industries. The important advantages of the prototype aregiven below Reduce manpower Increase productivity Eliminate unwanted fork trucks Reduce product damages Maintain better control of material management Traffic control is not needed in this system because of single carrier Suitable to transfer framesEach of the machines has their own merits and demerits. During the production wehad faced many problems. Much of them were solved during the assembling. But stillsome of them stand here, which can’t have to remove. The followings are thelimitations of the prototype fabricated: Installation cost is very high. AGVs are fragile and should be handled with care. Regular care, inspection and maintenance needed Should be recharged periodically AGV will stop delivery when it is forced off the path. Battery should be recharged during intervals. Sun light affect the movement.
  72. 72. Fabrication of Automatic Guided Vehicle64Department of Mechanical Engineering ACETREFERENCESwww.elsevier.com/locate/ejor/Survey of research in the design and controlof automated guided vehicle systemswww.jbtcorporation.com/en/Solutions/Automatic-Guided-Vehicleshttp://www.arduino.cc/www.atmel.com/devices/atmega328www.sunroms.comAutomation, Production Systems, And Computer Integrated Manufacturing, By Groover,Mikell.P, ISBN 8120334183