Pick and Place Robot Using Color Sensor
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SORTING OF OBJECTS THROUGH PICK AND PLACE ROBOTIC ARM A PROJECT REPORT
Submitted by GAURANG MARVANIA [Reg No: 11807024] GOURANGA NEOG [Reg No: 11807026] MAHARSHI THAKER [Reg No: 11807100]
Under the guidance of M.R. STALIN JOHN (Assistant Professor(SG), Department of Mechanical Engineering)
In partial fulfilment for the award of the degree Of BACHELOR OF TECHNOLOGY in MECHATRONICS ENGINEERING of FACULTY OF ENGINEERING & TECHNOLOGY
S.R.M. Nagar, Kattankulathur, Kancheepuram District MAY 2011 1
SRM UNIVERSITY (Under Section 3 of UGC Act,1956)
Certified that this project titled “SORTING OF OBJECTS THROUGH PICK AND PLACE ARRANGEMENT” is the bonafide work of “GAURANG MARVANIA (Reg No. 11807024), GAURANGO NEOG (Reg No. 11807026), MAHARSHI THAKER (Reg No. 11807100)”, who carried out the project work under my supervision. Certified further, that to the best of my knowledge the work reported herein does not form any other project report or dissertation on the basis of which a degree or award was conferred on an earlier occasion on this or any other candidate.
M.R. STALIN JOHN
Dr. B.K. VINAYAGAM
Department of Mechanical Engineering
Department of Mechatronics
ACKNOWLEDGEMENT It gives me immense pleasure to extend my gratitude to my Head of Department
B.K. VINAYAGAM for having given me an opportunity to carry out this project and providing with essential facilities.
This project is done under the guidelines of M. R. STALIN JOHN (Assistant Professor(SG) of Mechanical Engineering).He played a role of Engineer, Supervisor and an Educator in the journey of completion of the project. With his time to time association ship, we have derived valuable information, insight and inspiration about successfully completing the project. He has always been very cooperative and kind hearted and have helped us when we faced any problems or difficulty in understanding. We thank him sincerely.
We would also like thank the Faculty Members without whom this project would have been a distant reality. We also extend our heartfelt thanks to our family and well wishers. We owe a great many thanks to a great many people who helped and supported us during our journey towards finishing the project successfully.
The Project deals with an automated material handling system. It synchronizes the movement of robotic arm to pick the objects moving on a conveyor belt. It aims in classifying the coloured objects which are coming on the conveyor by picking and placing the objects in its respective pre-programmed place. Thereby eliminating the monotonous work done by human, achieving accuracy and speed in the work. The project involves colour sensors that senses the object’s colour and sends the signal to the microcontroller. The microcontroller sends signal to eight relay circuit which drives the various motors of the robotic arm to grip the object and place it in the specified location. Based upon the colour detected, the robotic arm moves to the specified location, releases the object and comes back to the original potion.
TABLE OF CONTENTS CHAPTER
BONAFIDE CERTIFICATE ACKNOWLEDGEMENT ABSTRACT 1.
1 1.1.1 BENEFITS OF
CONVEYORS 1.2 LITERATURE SURVEY
2.1.1 SENSING CIRCUIT
2.1.3 RECTIFIERS CIRCUIT
2.1.5 DC MOTORS
2.1.6 ROBOTIC ARM AND
GRIPPER 2.1.7 CONVEYOR BELT 3.
3.1 CONVEYOR BELT
3.1.4 BELT CONVEYOR
3.1.5 LINE SHAFT CONVEYOR
SYSTEMS 3.1.6 CONVEYOR SYSTEM
3.2 ROBOTIC ARM
3.2.1 THE GRABBER ARMS
3.2.2 ROBOTIC ARM
4.1 ELECTRONIC MODULE
MICROCONTROLLER 4.2.1 FEATURES
4.3 RELAY DRIVING CIRCUIT
4.3.1 OPERATION OF RELAY
4.4 COLOUR SENSING CIRCUIT
4.4.1 COLOUR SENSING
CIRCUIT 4.5INFRA RED (IR) SENSING CIRCUIT 4.5.1 OBJECT DETECTION
USING IR LIGHT
4.5.2 SENSOR ON TECHNIQUE
4.6 VOLTAGE CONVERTOR CIRCUIT
PROGRAMMING 5.1 COLOUR SENSING CODE
CHAPTER 1 INTRODUCTION 1.1 HISTORY Auto-motion first opened its doors in 1967 as a distributor of conveyors and conveyor accessories. It did not take long to realize that one could provide far greater service to the customers if one could also control the manufacturing aspects of the conveyor equipment. Auto-motion understood the value of providing service in every facet from design and production to installation, training and ongoing factory trained technical support. Simply stated, Auto-motion was providing Value Added Service long before it became a buzz word in the industrial world. Though it is suggested that ancient civilizations such as the Egyptians used conveyors in major construction projects, the history of the modern conveyor dates back to the late 17th century. These early conveyor systems were typically composed of a belt that travelled over a flat wooden bed. The belt was usually made from leather, canvas or rubber and was used for transporting large bulky items. It wasn't until the end of the Industrial Revolution that conveyors came to be used for a broader range of applications.
Hymle Goddard of Logan Company patented the first roller conveyor in 1908. Its initial applications were not very popular, and it wasn't until it was introduced in the automotive industry that it was able to prosper. In 1919, the first powered and free conveyors were introduced into the mass production of automobiles. The conveyor quickly became a popular means of transporting heavy materials within manufacturing facilities. The application of the conveyor branched out to coal mining in the 1920s, where the technology underwent considerable changes. Conveyor belts were designed made of layers of cotton and rubber coverings. During the manufacturing increase of World War II, manufacturers created synthetic materials to make belting because of the scarcity of natural components. Today's conveyor belting is made from an almost endless list of synthetic polymers and fabrics and can be tailored to any requirements. Possible uses of conveyors have broadened considerably since the early days and they are used in almost any industry where materials have to be handled, stored or dispensed. The longest conveyor belt currently in use operates in the phosphate mines of the Western Sahara and is over 60 miles long. Conveyors can be classified using the following criteria: •
Load: The type of product being handled (unit load or bulk load)
Location: Location of the conveyor (overhead, on-floor or in-floor)
Accumulation: Whether or not loads can accumulate on the conveyor
1.1.1 BENEFITS OF CONVEYORS Conveyors offer a wide range of benefits, many of which are readily apparent. Before the invention and implementation of conveyors, warehouse and factory workers needed to physically travel with an object from place to place. Not only was this cumbersome for the employee, it was inefficient for the company and, essentially, a huge waste of time. The conveyor brings a project to the worker, rather than a worker having 9
to travel to a project. Conveyors can be used to transport parts to workers or locations throughout a plant or warehouse and, eventually, to the shipping dock for delivery. Besides the obvious benefits of increased efficiency, conveyors can serve to increase quality control at a manufacturing or storage location. The use of automated production lines allows individual parts to be moved to and from automated machinery, allowing workers who were once designated to transporting parts to perform tasks that cannot as easily be automated, such as quality control or or supervision/management processes. In addition, conveyors can increase the safety of a facility. Specialty conveyors are designed to transport heavy or hazardous products, keeping workers out of harm's way. The history of conveyor belts begins in the latter half of the 17th century. Since then, conveyor belts have been an inevitable part of material transportation. But it was in 1795 that conveyor belts became a popular means for conveying bulk materials. In the beginning, conveyor belts were used only for moving grain sacks to short distances. The conveyor belt system and working were quite simple in the early days. The conveyor belt system had a flat wooden bed and a belt that traveled over the wooden bed. Earlier, conveyor belts were made of leather, canvas or rubber. This primitive conveyor belt system was very popular for conveying bulky items from one place to another. In the beginning of the 20th century, the applications of conveyor belts became wider. Hymle Goddard of Logan Company was the first to receive the patent for the roller conveyor in 1908. The roller conveyor business did not prosper. A few years later, in 1919, powered and free conveyors were used in automotive production. Thus, conveyor belts became popular tools for conveying heavy and large goods within factories. During the 1920s, conveyor belts were common, and also underwent tremendous changes. Conveyor belts were used in coal mines to handle runs of coal for more than 8kms, and were made using layers of cotton and rubber covers. The longest conveyor belt now in use is 60 miles long, in the phosphate mines of Western Sahara. 10
One of the turning points in the history of conveyor belts was the introduction of synthetic conveyor belts. It was introduced during the Second World War, mainly because of the scarcity of natural materials such as cotton, rubber and canvas. Since then, synthetic conveyor belts have become popular in various fields. With the increasing demand in the market, many synthetic polymers and fabrics began to be used in the manufacture of conveyor belts. Today, cotton, canvas, EPDM, leather, neoprene, nylon, polyester, polyurethane, urethane, PVC, rubber, silicone and steel are commonly used in conveyor belts. Nowadays, the material used for making a conveyor belt is determined by its application.
1.2 LITERATURE REVIEW Tsalidis and Dentsoras (1998) describes in this paper that conveyor belt design is examined as an application of a proposed Design Parameters Space Search technique. First, the main characteristics of the belt-conveyor design process are presented as they appear in the current literature. Furthermore, a proposed general knowledgerepresentation platform is described, and its ability to house the relevant conveyor design knowledge is also shown. The extended search technique of the design space is discussed, and an integrated example of a belt-conveyor design is presented, based on the proposed representation platform and the extended search technique. Huang et al., (2007) describes in this paper deals with the time-minimum trajectory planning of a 2-DOF translational parallel robot named the Diamond for rapid pick-andplace operations. Kinematics and dynamics of the robot are formulated using a parametric function, allowing the representation of the input torque and velocity constraints to be converted to those in terms of the path length. A modified algorithm for achieving the minimized traversal time is proposed by taking into account the path jerk limit. Lithiumion battery sorting using the Diamond robot is taken as an example to demonstrate the applicability of this approach. Dogan Ibrahim (2007) aims to show the special features of the C language when programming microcontrollers. He says that the industry standard C51 optimizing C 11
compiler is used throughout. This compiler has been developed by Keil Elektronik GmbH. C51 is available on both MS-DOS and Windows-based operating systems and the compiler implements the American National Standards Institute (ANSI) standard for the C language. There are many other high-level language compilers available for microcontrollers, including PASCAL, BASIC, and other C compilers. Some of these compilers are freely available as shareware products and some can be obtained from the Internet with little cost. These compilers can be used for learning the features of a specific product and in some cases small projects can be developed with such compilers. The C51 compiler has been developed for the 8051 family of microcontrollers. This is one of the most commonly used industry standard C compilers for the 8051 family, and can generate machine code for most of the 20-pin and 40-pin 8051 devices and its derivatives, including the following microcontrollers: Intel and others 8051, 80C51, and 87C51 Atmel 89C51, 89C52, 89C55, 89S8252, and 89S53.51 an Sahu, et al.,(2007) describes the outline of the development of the colour sensor meant for the radiation-robot used for the alignment of sample for various experiments in a radiation environment near nuclear beam line of 3MV Tandem pelletron Accelerator at Institute of Physics, Bubaneswar. In this paper a comparative study between the APD and LDR for their sensitivity towards different colours also discussed. A cost effective as well as with reasonable accuracy and precision, a colour sensor is developed with a array of LDRs, where the biasing voltage is very less compared to APD based colour sensor. This sensor is used in a micro-controller based robotic arm and successfully able to distinguish 8 colors. This can be enhanced to 256 colors. This work is the first developmental stage of the robot, which will be used for alignment of the sample sensing laser of different colour in high-dose radiation environment. Khojastehnazhand,et al., (2010) Grading systems give many kinds of information such as size, colour, shape, defect, and internal quality. Among these colour and size are the most important features for accurate classification and/or sorting of citrus such as oranges, lemons and tangerines. Basically, two inspection stages of the system can be identified: external fruit inspection and internal fruit inspection. The former task is accomplished 12
through processing of colour images, while internal inspection requires special sensors for moisture, sugar and acid contents. In this paper, an efficient algorithm for grading lemon fruits is developed and implemented in visual basic environment. The system consists of two CCD cameras, two capture cards, an appropriate lighting system, a personal computer and other mechanical parts. The algorithm initially extracts the fruit from the background. The samples of different grades of lemon are situated in front of the cameras and are calibrated off-line. Then information on the HSI colour values and estimated volumes of fruits are extracted and saved in a database. By comparing the information during sorting phase with the available information inside the database, the final grade of the passing fruits is determined. This algorithm can be easily adapted for grading and/or inspection of other agricultural products such as cucumber and eggplant.
CHAPTER 2 METHODOLOGY 230 Volts AC Power Supply 12-0-12 Step down Transformer Rectifier and Filter circuit
Sensing Circuit The colour object on the conveyor moves towards ` sensing unit The colour of the object is identified
The microcontroller receives the signal from sensing unit. The Robotic arm receives the signal The gripper closes and picks the object and robotic moves to dropping point The robotic arm moves to its ground position Fig. 2.1 Methodology
The working of object sorting system using colour sensor and pick and place robot is described in steps as follows: Objects on the running conveyor are classified into three categories based on the colour. When the object passes through the sensing circuit it identifies the colour of the object on the conveyor and sends signals to the micro-controller.
2.1.1 SENSING CIRCUIT: This circuit can be used to sense and differentiate between different colours. This circuit demonstrates the principle and operation of a simple colour sensor using LDR. The circuit is divided into three parts: Detector (LDR), Comparator and Output. When light of a particular colour falls on LDR, its resistance decreases and an output voltage is produced. This voltage is dependent on the intensity and wavelength of different colour. For it is needed to set reference voltage of comparator according to the requirement. For example, If set reference voltage at positive pin with 0.38volts, the LDR becomes sensitive to blue light. When blue light falls on the LED, an output of approximate voltage 0.28V is produced, this glows the output LED.
But if a yellow colour light on LDR then input voltage at the comparator is around 0.7 volts at the negative pin of comparator and the output LED doesn’t glow. There are three LEDs of Red, Blue and Green are arranged along with special LDRs which will just allow either Red, Blue or Green lights to pass through. The working principle of LDR is that when a light falls of LDR its resistance reduces and it allows the current to pass through it. When the light from the LED falls on any of the three coloured object, it will reflect back on the LDR. These LDR will only allow any one colour to pass through it and this is how it will sense the colour of the object. There are LEDs placed in order to let the user know that which coloured object has been sensed by the sensing circuit. There is a varactor diode which will allow the user to vary the reference voltage in order to accurately sense the three colours. The signals from the sensing circuit are sent to the controller circuit consisting of power circuit, rectifier circuit and micro-controllers.
2.1.2TRANSFORMER: By appropriate selection of the ratio of turns, a transformer thus allows an alternating current (AC) voltage to be "stepped up" by making Ns greater than Np, or "stepped down" by making Ns less than Np. Here, the 230volts power supply from the mains if transformed by a 12-0-12V step-down centre tap transformer. This AC voltage is needed to be converted to DC for supplying it to controllers and DC motors. A transformer is a static device that transfers electrical energy from one circuit to another through inductively coupled conductors—the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field through the secondary winding. This varying magnetic field induces a varying electromotive force (EMF) or "voltage" in the secondary winding. This effect is called mutual induction. If a load is connected to the secondary, an electric current will flow in the secondary winding and electrical energy will be transferred from the primary circuit through the transformer to the load. In an ideal transformer, the induced voltage in the 16
secondary winding (Vs) is in proportion to the primary voltage (Vp), and is given by the ratio of the number of turns in the secondary (Ns) to the number of turns in the primary (Np) as given in Eq. 1.
2.1.3 RECTIFIERS CIRCUIT: The signals from the micro-controller are then given to the robotic arm through the switching circuit. These signals will control the arm and gripper movement and will place the object picked from conveyor belt to three different places in order to segregate them. The switching circuit gives the option of manual operation of arm movement as well as gripper operation. The automation switch on the board will operate the system automatically. A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which is in only one direction, a process known as rectification. A full-wave rectifier is used ,which converts the whole of the input waveform to one of constant polarity (positive or negative) at its output. Fullwave rectification converts both polarities of the input waveform to DC (direct current), and is more efficient.6A diodes are used for voltage rectification. Therefore the AC voltage is now converted pulsating DC. While half-wave and full-wave rectification suffice to deliver a form of DC output, neither produces constant-voltage DC. In order to produce steady DC from a rectified AC supply, a smoothing circuit or filter is required. This pulsation is removed by 1000micro-farad capacitor filter circuit. Sizing of the capacitor represents a tradeoff. For a given load, a larger capacitor will reduce ripple but will cost more and will create higher peak currents in the transformer secondary and in 17
the supply feeding it. In extreme cases where many rectifiers are loaded onto a power distribution circuit, it may prove difficult for the power distribution authority to maintain a correctly shaped sinusoidal voltage curve. The output of the filter circuit is pure DC which is then supplied to controllers, motors and sensors.
2.1.4 RELAYS: A relay is an electrically operated switch. Many relays use an electromagnet to operate a switching mechanism mechanically, but other operating principles are also used. Relays are used where it is necessary to control a circuit by a low-power signal (with complete electrical isolation between control and controlled circuits), or where several circuits must be controlled by one signal. The first relays were used in long distance telegraph circuits, repeating the signal coming in from one circuit and retransmitting it to another. Relays were used extensively in telephone exchanges and early computers to perform logical operations. A type of relay that can handle the high power required to directly control an electric motor is called a contractor. Solid-state relays control power circuits with no moving parts, instead using a semiconductor device to perform switching. Relays with calibrated operating characteristics and sometimes multiple operating coils are used to protect electrical circuits from overload or faults; in modern electric power systems these functions are performed by digital instruments still called "protective relays". In this system DC Motors for gripper, turn table, robotic arm and conveyor belt are connected through the relay circuit.
2.1.5 DC MOTORS: Motor Details •
Gripper: 9V, 60 rpm
Turn Table: 24V, 30 rpm
Up/Down: 12V, 30 rpm 18
The DC motors are used to control the arm and turn table movement are connected to controller circuit and receives signals from micro-controller. There are IR sensors installed in order to accurately identify ground and drop places An electric motor converts electrical energy into mechanical energy. DC motor design generates an oscillating current in a wound rotor, or armature, with a split ring commutator, and either a wound or permanent magnet stator. A rotor consists of one or more coils of wire wound around a core on a shaft; an electrical power source is connected to the rotor coil through the commutator and its brushes, causing current to flow in it, producing electromagnetism. The commutator causes the current in the coils to be switched as the rotor turns, keeping the magnetic poles of the rotor from ever fully aligning with the magnetic poles of the stator field, so that the rotor never stops (like a compass needle does) but rather keeps rotating indefinitely (as long as power is applied and is sufficient for the motor to overcome the shaft torque load and internal losses due to friction, etc.).
2.1.6 ROBOTIC ARM AND GRIPPER: Gripper: 9V, 60 rpm, DC motor is used to control the gripper movement, for opening and closing of the gripper. The DC motor receives its signal from the controller for performing gripping and dropping operations. The gripper has been specially designed in order to grip rectangular or square objects from the running conveyor and dropping them at programmed locations. An industrial robot is defined as automatically controlled, reprogrammable, multipurpose manipulator programmable required axes. The parameters such as Degrees of freedom, Work Volume, Payload, accuracy, repeatability, acceleration and robot kinematics are considered before designing the robotic arm. The robotic arm movements are controlled by the DC motor of 25 rpm. Its motion is restricted by placing the IR sensor and programming the controller accordingly to limit the robotic arm’s movements.
2.1.7 CONVEYOR BELT: 19
Here, the conveyor motor receives power and signal from the central supply through rectifier and control circuit. The control circuit consisting of an potentiometer will allow the user to manually control the speed of conveyor belt by the regulatory knob. Polyester is used as a belt material.
A conveyor belt consists of two or more pulleys, with a continuous loop of material - the conveyor belt - that rotates about them. One or both of the pulleys are powered, moving the belt and the material on the belt forward. The powered pulley is called the drive pulley while the unpowered pulley is called the idler. There are two main industrial classes of belt conveyors; those in general material handling such as those moving boxes along inside a factory and bulk material handling such as those used to transport industrial and agricultural materials, such as grain, coal, ores, etc. generally in outdoor locations.
CHAPTER 3 EXPERIMENTAL SETUP 3.1 CONVEYOR SYSTEM 3.1.1 FRAMES Standard gravity conveyor frame widths are 305mm, 460mm and 610mm overall. Conveyor frames are stocked in both 1.5 metre and 3 metre lengths. Frames are supplied with either “butting plates” (standard) or hook and bar attachments to secure each segment together. Standard frames are supplied in a “hammer tone” blue spray painted finish. Other colours or finishes are available on request e.g., Powder coated, galvanised finish or stainless steel.
3.1.2 ROLLERS Standard rollers for the conveyor frames are 50.8mm diameter. They are available in PVC (25kg capacity), Black Steel and Galvanised Steel in both Medium Duty (140kg capacity) and Heavy Duty (200kg capacity) versions to suit varying loads or conditions. Stainless steel rollers for wash-down or corrosive applications are used. Spring loaded axles slot into holes along the frame. On PVC and Medium Duty rollers one end is a D shape whilst the other is round. This allows for easy replacement of damaged rollers. Heavy Duty rollers are supplied with 12mm shafts. Precision or stainless steel bearings are available for frame work.
3.1.3 SUPPORTS Two types of standard supports are available. Both styles provide adjustment from 600 – 1000mm to “Top of Roller”. Other support styles and complete frames are used to special support. RHS Supports are bolted to the underside of the conveyor frame via a crescent (smiley) plate. This plate provides allowance for any angular misalignment. 22
Pipe stands are also available for economy or for applications where the conveyor may be moved on a frequent basis. Normally, supports are only placed on every conveyor join (3 stands for 2 frames). Curves always require 2 stands for proper stability.
3.1.4 BELT CONVEYOR A conveyor style utilizes a flat belt running on a flat fabricated steel deck or over rollers. They are used where smooth and quiet transport of product is desirable, and is ideally suited to irregular shaped product that cannot easily be moved on other conveyor styles. Examples of applications other than cartons or tote bins would be the movement of floppy sacks or satchels, bags of powder or flour, or raw food products. This is an excellent conveyor for handling items that may have loose strings or tapes attached that would otherwise get caught in other conveyor styles. Belt conveyors provide a smooth solution for situations where one need a change in elevation— for example inter floor situations or to receive or deliver products to a mezzanine level. They are also ideally suited to: Metering— precise positioning Scanning— in conjunction with code readers Tracking— where precise positional control is required for sorting Induction— precise feeding into other conveyors at junctions
3.1.5 LINE SHAFT CONVEYOR SYSTEMS Line shaft is an economical method of conveying flat bottomed product. A series of rollers, each driven by a polyurethane band connected to a single rotating shaft, mounted within the conveyor body, drive the product through the system. Lineshaft conveyors are made as standard in widths of 245mm, 398mm and 550mm (measured between frames).
This style of conveying is ideal in warehouse order picking applications or where cartooned product is being transported through a manufacturing process. It provides minimum pressure accumulation, quiet operation and easy installation. Line shaft conveyors are suitable for transportation of products within warehouse or manufacturing operations where lighter weight cartons, tote bins and other products need to be moved, allowing for a variety of situations requiring directional changes. Limited, minimal pressure accumulation of product can be obtained with this style of conveyor. Straight modules, curves and merges, slave drive assemblies, under roller brakes, pneumatic blade stops, personnel gates and many other accessories for this product line. Due to the nature of line shaft, one drive can power many metres of conveyor, making it extremely economical.
3.1.6 CONVEYOR SYSTEM Figure 3.1 shows the overview of conveyor system.
Fig. 3.1 Conveyor system 25
3.2 ROBOTIC ARM Drill a hole in the base 8 cm from the front and to the side so the disk is close to one side. This will leave room for the piston that moves it on the other side. Cut a 4 cm dowel and glue it in the base. Slide the disk over the dowel and glue down the 2.5 cm piece over the disk. This way the disk will rotate, but not come off. The right side of the support structure has two screw eyes; the one on the inside is big enough for the syringe tube and is 2.5 cm up from the bottom. The one on the outside can be smaller since it only will have a wire in it, and it is . 5 of a cm from the bottom and .5 cm from the back (the long side of the base is the back). One can use a big one on the outside if that is all one have. Screw them in before one glue the pieces to the disk since it is easier (especially the inside one). Cut a piece of dowel to fit in the holes 6 cm from the bottom. It should be long enough to go to the outside edge of the support structure, so the structure is exactly 3.2 cm across. The long arm should be 3.2 cm across, (measure your drying long arm) so the space here has to Insert pegs in the top holes so they stick in 1 cm, this will hold the long arm. They don’t need to be glued since there is no motion that will work them loose, and it’s nice to be able to remove them let this dry and go on to the grabber arms.
3.2.1 THE GRABBER ARMS This is the part that shows if one have cut and drilled with accuracy! Start off by looking at the diagram and checking out where things will go.For the Grabber arms one will need 7 pieces of cut dowel. • 3 at 3 cm long • 4 at 4 cm long The dowels will insert into the holes and a tube is pushed over the end to hold them in place. So one need 10 tubes cut .5 of a cm. This is the 6mm tubing that is a bit bigger than the tubing one use for the syringes. Did one get all that? To finish, place the 4 cm dowel through the long arm, through a wooden spacer and then through the bottom arm, as shown here. 26
Do the same for the other side and one are ready for the claws! Place tubing over the dowels to hold them in place. There should be .5 cm on each side of the arm for the tubing. There are two ways one can attach them. The researchers have decided that they are both fine and one can use whichever technique one want (in a vote 42 to 5) .Either ways, one need a wooden spacer on the arm on the right. On these pieces the dowel doesn’t need a rubber holder since they are going to be gluedand the dowel should be flat on the claw. Trim the dowel with a pair of small wires nippers if they are too long. Move the linkage in and out with your hands and adjust the claws so they are at the correct angle, and they don’t bind with each other. If they hit each other and don’t nicely mesh then take them off and sand them so they slide together. Once they are smoothly meshing and at an angle that one like, put glue on the dowels and push them in. 1. The cardboard robotic arm must have a sturdy base. If it is not secured it will topple over when it attempts to pick up the object. 2. The cardboard robotic arm must have at least two parts to the limb. These are generally referred to as the biceps and the forearm. Some cardboard robotic arms also have hands or fingers. 3. The cardboard robotic arm must have at least two joints. The elbow joint enables it to bend over to the object. The wrist or finger joints allow it to pick up the object. Some cardboard robotic arms also have a third joint at the shoulder near the base. 4. The cardboard robotic arm must have a muscle system. This powers it through its motions. This can be human muscle pulling strings, hydraulics pushing liquid or electricity sending impulses to motors.
3.2.2 ROBOTIC ARM Figure 3.2 shows robotic arm with Two Degree of Freedom
GRIPPER WOODEN BASE
INFRA RED SENSORS
COLOUR SENSING CIRCUIT
Fig.3.2 Robotic Arm
3.1.3 GRIPPER 28
Figure 3.3 shows the gripper design that can grip square and rectangular objects. GRIPPER MOTOR
4.1 ELECTRONIC MODULE Figure.4.1 represents Electronic Module contains Microcontroller circuit, Relay Circuit, Infrared Sensors and Voltage Converting Circuits.
TRANSFORMER FOR GRIPPER MOTOR
AC TO DC CONVERTOR CIRCUIT 29
RELAY CIRCUIT TRANSFORMER 12-0-12
Fig.4.1 Electronic module AC TO DC CONVERTOR CIRCUIT
SPEED CONTROL OF CONVEYOR
4.2 INTERFACING OF MICROCONTROLLER TO RELAY CIRCUIT BY DARLINGTON array (ULN DRIVER) One option for driving relays would be to use a high-voltage, high-current, MANUAL OPERATION
Darlington array driver IC suchBOARD as the ULN2803. The ULN2803 can directly interface to SWITCH CIRCUIT the data outputs of the 8051 pins, and provides much higher drive-current. The ULN2803 also has internal diode protection that eliminates the need for the fly-back diode as shown in the above relay driver schematics. One can connect 8 relay using this IC. It is always best connecting the switch to ground with a pull-up resistor as shown in the "Good" circuit. When the switch is open, the 10k resistor supplies very small current needed for logic 1. When it is closed, the port pin is short to ground. The voltage is 0V and the entire sinking current requirement is met, so it is logic 0. The 10k resistor will pass 0.5 mA (5 Volt/10 k ohms). Thus the circuits waste very little current in either state. The drawback is that the closure of switch gives logic 0 and people like to think of 30
switch closure gives logic 1. But this is not a matter because it is easy to handle in software. The ULN2003 is a monolithic high voltage and high current Darlington transistor arrays. It consists of seven NPN Darlington pairs that feature high-voltage outputs with common-cathode clamp diode for switching inductive loads. The collector-current rating of a single Darlington pair is 500mA. The Darlington pairs may be paralleled for higher current capability. Applications include relay drivers, hammer drivers, lamp drivers, display drivers (LED gas discharge), line drivers, and logic buffers. The ULN2003 has a 2.7kW series base resistor for each Darlington pair for operation directly with TTL or 5V CMOS devices. The ULN driver details are shown in Fig. 4.2.
4.2.1 FEATURES * 500mA rated
types of logic. * Relay driver application
Fig. 4.2 ULN 2803
4.3 RELAY DRIVING CIRCUIT This project uses relay circuit board to control various parameters of project. It uses 8 relay board. The relay acts as a switch for parameters like turn table, shoulder of robot and gripper. A relay is usually an electromechanical device that is actuated by an electrical current. The current flowing in one circuit causes the opening or closing of another circuit. Relays are like remote control switches and are used in many applications because of their relative simplicity, long life, and proven high reliability. Relays are used 32
in a wide variety of applications throughout industry, such as in telephone exchanges, digital computers and automation systems. Highly sophisticated relays are utilized to protect electric power systems against trouble and power blackouts as well as to regulate and control the generation and distribution of power. In the home, relays are used in refrigerators, washing machines and dishwashers, and heating and air-conditioning controls. Although relays are generally associated with electrical circuitry, there are many other types, such as pneumatic and hydraulic. Input may be electrical and output directly mechanical, or vice versa. Relays are components which allow a low-power circuit to switch a relatively high current on and off, or to control signals that must be electrically isolated from the controlling circuit itself. Newcomers to electronics sometimes want to use a relay for this type of application, but are unsure about the details of doing so. Here is a quick rundown. To make a relay operate, one has to pass a suitable pull-in and holding current (DC) through its energising coil. Generally relay coils are designed to operate from a particular supply volt. Small relay have operation between 12V and 5V. In each case the coil has a resistance which will draw the right pull-in and holding currents when it is connected to that supply voltage. So the basic idea is to choose a relay with a coil designed to operate from the supply voltage one.re using for your control circuit (and with contacts capable of switching the currents one want to control), and then provide a suitable relay driver circuit so that your low-power circuitry can control the current through the relays coil. Typically this will be somewhere between 25mA and 70mA.
4.3.1 OPERATION OF RELAY All relays contain a sensing unit, the electric coil, which is powered by AC or DC current. When the applied current or voltage exceeds a threshold value, the coil activates the armature, which operates either to close the open contacts or to open the closed contacts. When a power is supplied to the coil, it generates a magnetic force that actuates the switch mechanism. The magnetic force is, in effect, relaying the action from one circuit to another. The first circuit is called the control circuit; the second is called the load circuit. Figure 4.3 gives the internal detail of relay circuit and Fig 4.4 shows eight relay circuit diagram with ULN driver which drives the various motors of Robotic Arm. 33
There are three basic functions of a relay: On/Off Control, Limit Control and Logic Operation.
On/Off Control: Example: Air conditioning control, used to limit and control a “high power load”, such as a compressor Limit Control: Example: Motor Speed Control, used to disconnect a motor if it runs slower or faster than the desired speed Logic Operation: Example: Test Equipment, used to connect the instrument to a number of testing points on the device under test.
Fig. 4.3 Eight relays circuit
Fig. 4.4 Eight relay circuit diagram with ULN driver
4.4 COLOUR SENSING CIRCUIT The colour sensing circuit of the project contains three different coloured LED emitter and three separate receivers. The light is reflected off of the target such as a blue piece of paper and returns to the sensor. The receivers are tuned to look for a specific wavelength of light working out its RGB or Red, Green and blue values. The light sensors are able to record the components of the reflected light and its intensity. The sensor then compares these values to the settings on the computer to determine the necessary action. Many of the colour sensors today have the ability to recognize Red, Blue, Green (RGB) or primary. Figure 4.5 shows the colour sensing circuit. Programmable tolerance settings in the sensor also make it possible to tightly control the match of the target to the programmed value. This capability is important
when sorting or matching objects of similar colour. The more exact the required match, the more tight the colour tolerance level is set. Fig. 4.5 Colour sensor
LDRs or Light Dependent Resistors are very useful especially in light/dark sensor circuits. Normally the resistance of an LDR is very high, sometimes as high as 1000 000 ohms, but when they are illuminated with light resistance drops dramatically. When a light level of 1000 lux (bright light) is directed towards it, the resistance is 400R (ohms). When a light level of 10 lux (very low light level) is directed towards it, the resistance has risen dramatically to 10.43M (10430000 ohms).
Fig. 4.6 LED based LDR Sensor When the light level is low the resistance of the LDR is high. This prevents current from flowing to the base of the transistors. Consequently the LED does not light. Figure 4.6 shows LED based LDR Sensor However, when light shines onto the LDR its resistance falls and current flows into the base of the first transistor and then the second transistor. The LED lights. The preset resistor can be turned up or down to increase or decrease resistance, in this way it can make the circuit more or less sensitive. 38
The LEDs are water clear when turned off. Black electrical tape surrounds the photocell in the center of the LEDs. The tape blocks the direct light from the LEDs from reaching the photocell, thus detecting only reflected light. After the amount of red light, green light, and blue light is measured, each component is individually scaled based on minimum and maximum values obtained at calibration. One-time calibration consists of aiming the completed sensor first at a white piece of paper and then at a piece of black conductive foam. The maximum and minimum values are plugged into the EEPROM of the microcontroller. Scaling based on actual data allows the individual attributes of that particular sensor and set of LEDs to be accounted for. Alternatively, one can adjust the balance of the colours in hardware by using with three separate trimpots (trimmer potentiometers). Dialing a trimpot changes the brightness of a particular LED. For example, if there is too much red light being sensed, simply increase the resistance to decrease the LED brightness by turning the trimpot attached to the red LED. Include a minimum fixed resistor value (100 ohms to 150 ohms) in series with each trimpot so that if one accidentally dial the trimpot to 0 ohms the LED won't be damaged. The object whose colour is required to be detected should be placed in front of the system. The light rays reflected from the object will fall on the three convex lenses which are fixed in front of the three LDRs. The convex lenses are used to converge light rays. This helps to increase the sensitivity of LDRs. Blue, green and red glass plates (filters) are fixed in front of LDR1, LDR2 and LDR3 respectively. When reflected light rays from the object fall on the gadget, the coloured filter glass plates determine which of the LDRs would get triggered. When a primary coloured light ray falls on the system, the glass plate corresponding to that primary colour will allow that specific light to pass through Fig 4.7. But the other two glass plates will not allow any light to pass through. Thus only one LDR will get triggered and the gate output corresponding to that LDR will become logic 1 to indicate 39
which colour it is. Similarly, when a secondary coloured light ray falls on the system, the two primary glass plates corres- ponding to the mixed colour will allow that light to pass through while the remaining one will not allow any light ray to pass through it. As a result two of the LDRs get triggered and the gate output corresponding to these will become logic 1 and indicate which colour it is. When all the LDRs get triggered or remain untriggered, one will observe white and black light indications respectively. Following points may be carefully noted: 1. Potmeters VR1, VR2 and VR3 may be used to adjust the sensitivity of the LDRs. 2. Common ends of the LDRs should be connected to positive supply. 3. Use good quality light filters. The LDR is mounded in a tube, behind a lens, and aimed at the object. The coloured glass filter should be fixed in front of the LDR as shown in the figure. Make three of that kind and fix them in a suitable case. Adjustments are critical and the gadget performance would depend upon its proper fabrication and use of correct filters as well as light conditions. Figure 4.8 shows LDR with cellophane filter.
Fig. 4.7 LDR with cellophane filter
4.4.1 COLOUR SENSING CIRCUIT Figure 4.8 shows the circuit which is the combination of LDR, LED and voltage Voltage comparator. Comparator Voltage Comparator LEDs
GREEN LDR POTENTIOMETER
Volta Voltag Volt Voltage Com
BLUE LDR 41
Fig 4.8 Colour sensing circuit
4.5 INFRA RED (I.R.) SENSING CIRCUIT
4.5.1 OBJECT DETECTION USING IR LIGHT It is the same principle in ALL Infra-Red proximity sensors. The basic idea is to send infra red light through IR-LEDs, which is then reflected by any object in front of the sensor. Then all one have to do is to pick-up the reflected IR light. For detecting the reflected IR light that was emitted from another led of the exact same type! This is an electrical property of Light Emitting Diodes (LEDs) which is the fact that a led Produce a voltage difference across its leads when it is subjected to light(Fig 4.9). As if it was
can't be - in
from light, It
that's why as one will notice in the schematic, Op-Amp (operational Amplifier) will accurately detect very small voltage changes. Both the sender and the receiver are constructed on the same board. Fig 4.9 I.R. Sensing logic
4.5.2 SENSOR ON TECHNIQUE As the name implies, the sensor is always ON, meaning that the IR led is constantly emitting light. This design of the circuit is suitable for counting objects, or counting revolutions of a rotating object, that may be of the order of 15,000 rpm or much more. However this design is more power consuming and is not optimized for high ranges. in this design, range can be from 1 to 10 cm, depending on the ambient light conditions. As one can see the schematic is divided into 2 parts the sender and the receiver. The sender is composed of an IR LED (D2) in series with a 470 Ohm resistor, yielding a forward current of 7.5 mA. The receiver part is more complicated, the 2 resistors R5 and R6 form a voltage divider which provides 2.5V at the anode of the IR LED (here, this led will be used as a sensor). When IR light falls on the LED (D1), the voltage drop increases, the cathode's voltage of D1 may go as low as 1.4V or more, depending on the light intensity. This voltage drop can be detected using an Op-Amp (operational Amplifier LM358). One will have to adjust the variable resistor (POT.) R8 so the the voltage at the positive input of the OpAmp (pin No. 5) would be somewhere near 1.6 Volt. if one understand the functioning of Op-Amps, one will notice that the output will go High when the volt at the cathode of D1 drops under 1.6. So the output will be High when IR light is detected, which is the purpose of the receiver(Fig 4.10).
Fig 4.10 I.R. Sensor The op-amp has 2 input, the +ve input, and the -ve input. If the +ve input's voltage is higher than the -ve input's voltage, the output goes High (5v, given the supply voltage in the schematic), otherwise, if the +ve input's voltage is lower than the -ve input's voltage, then the output of the Op-Amp goes to Low (0V). It doesn't matter how big is the difference between the +ve and -ve inputs, even a 0.0001 volts difference will be detected, and the the output will swing to 0v or 5v according to which input has a higher voltage.
An Infrared sensor is an electronic device that measures infrared (IR) light radiating from objects in its field of view. PIR sensors are often used in the construction of PIR-based motion detectors apparent motion is detected when an infrared source with one temperature, such as a human, passes in front of an infrared source with another temperature, such as a wall. All objects above absolute zero emit energy in the form of radiation. Usually infrared radiation is invisible to the human eye but can be detected by electronic devices designed for such a purpose. The term passive in this instance means that the PIR device does not emit an infrared beam but merely passively accepts incoming infrared radiation. “Infra” meaning below the ability to detect it visually, and “Red” because this colour represents the lowest energy level that ones eyes can sense before it becomes invisible.
Thus, infrared means below the energy level of the colour red, and applies to many sources of invisible energy. This sensor can be used for most indoor applications where no important ambient light is present. For simplicity, this sensor doesn't provide ambient light immunity, but a more complicated, ambient light ignoring sensor should be discussed in a coming article. However, this sensor can be used to measure the speed of object moving at a very high speed, like in industry or in tachometers. In such applications, ambient light ignoring sensor, which rely on sending 40 Khz pulsed signals cannot be used because there are time gaps between the pulses where the sensor is 'blind'... The solution proposed doesn't contain any special components, like photo-diodes, photo-transistors, or IR receiver ICs, only a couple if IR leds, an Op amp, a transistor and a couple of resistors (Fig. 4.11). In need, as the title says, a standard IR led is used for the purpose of detection. Due to that fact, the circuit is extremely simple, and any novice electronics hobbyist can easily understand and build it.
Fig 4.11 I.R. Sensing unit.
4.6 VOLTAGE CONVERTOR CIRCUIT Many electronic devices, from computers to TVs to cell phone chargers, require various DC (direct current) voltages to supply power to their circuitry. For those appliances and devices that get their power by plugging them into an electrical wall outlet, a circuit must be designed to convert the 120 volt AC power to a desired DC voltage. Alternating current, as is found in your home's electric outlets, changes polarity 60 times a second, referred to as "60 Hertz," or "60 cycles". The voltage increases from zero to its maximum positive voltage and then swings below zero to its maximum negative voltage, in a smooth sine wave transition. In a DC voltage supply, the polarity remains constant; plus (+) and minus (-) polarity points do not change, as with a flashlight battery. Use one semiconductor diode to obtain a DC voltage from an AC source. Simply place the diode in one of the two legs of the incoming AC source. One side of a diode is the "anode" or positive side, and the other is the "cathode" or negative side. When the leg of the AC source is connected to the anode of the diode goes positive, the diode allows current to flow through. Placing a volt meter on the cathode side will register the positive voltage present. As the leg connected to the diode's anode turns negative during the AC cycle, the diode acts as a block, and does not let the negative 46
voltage through. Thus, the "output" on the cathode side of the diode will always be positive. While this simple "rectifier" or "AC to DC converter" circuit helps explain how a diode works as a rectifier, the circuit only recovers half of the AC voltage cycle. Also, although the circuit's output is only positive, there is no output during the negative half of the input cycle. Connect two diodes to the output of a transformer that has a "center tap" such that both the positive and negative part of the AC cycle are converted. Often, a step-down transformer is used to change the 120 volts from the wall outlet down to a voltage needed by the device. Transformers and diode combinations are used in "wall warts" or power adaptors, many of which are probably around your home for cell phone chargers and phone answer machines. In a two-diode configuration, connect the anode end of a diode on one leg of the transformer and also connect the anode end of a second diode to the other transformer leg. The transformer must have a "center tap" connection. This will be the "ground" or negative connection. Connect the cathode end of both diodes together. This will be the positive DC output connection. Place an electrolytic capacitor across the DC output of the rectifier circuit --using either the two-diode or four-diode configuration--to further smooth out the DC voltage created by the full wave rectifier. Observe the polarity of the capacitor, connecting the positive end to the positive output of the rectifier circuit, and the negative end to the ground, or minus, connection--which is the transformer's center tap in the case of a bridge rectifier. The voltage rating on the capacitor must be higher than the DC output voltage-with no "load" connected. Formulas have been devised to calculate the best capacitance value, but generally, a large capacitor value will reduce ripple significantly. Start by experimenting with a value of 100 microfarads for a circuit with a 12 volt output. An oscilloscope can be used to see the effect of a capacitor on ripple smoothing. Figure 4.12 shows voltage convertor circuit which converts 220V to 35V.
Fig 4.12 Voltage convertor circuit
CHAPTER 5 MICRO CONTROLLER (89C51) PROGRAMMING 5.1 COLOUR SENSING CODE ;.......PICK & PLACE ROBO ......... ;....... CRSTAL FREQUENCY= 11.0592 MHZ................. ;...AUTOMATED USING COLOUR SENSORS....
ORG 00H JMP
START ORG 030H
START: MOV P1,#0FFH MOV P3,#0FFH MOV P2,#00H MOV P0,#0FFH
CALL DELAY2 CALL DELAY2 CALL AUTOMATION
CALL DEBOUNCE JMP
;............................................................... DEBOUNCE: MOV R1,#20 K1:
MOV R2,#20 DJNZ R2,$ DJNZ R1,K1 RET
;.............................................................. TURNTABLE_RIGHT: SETB TURNTABLE_A CLR
CALL STOP RET ;.............................................................. TURNTABLE_LEFT: CLR
SETB TURNTABLE_B JNB
CALL STOP RET
;.............................................................. SHOULDER_UP: SETB SHOULDER_A CLR
CALL STOP RET ;................................................................ SHOULDER_DOWN: CLR
SETB SHOULDER_B JNB
CALL STOP RET ;............................................................... GRIPPER_OPEN: SETB GRIPPER_A CLR
CALL STOP RET ;...............................................................
SETB GRIPPER_B JNB
CALL STOP RET ;............................................................... STOP: MOV P2,#00 RET ;............................................................... AUTOMATION: J1:
RET ;............................................. DOWN_FUNCTION: CALL SHOULDER_DOWN2 CALL DELAY2 CALL DELAY2 CALL DELAY2 JB
CALL STOP CALL DELAY2 RET ;.......................................... UP_FUNCTION: CALL SHOULDER_UP2 CALL DELAY2 CALL DELAY2 CALL DELAY2 JB
CALL STOP RET
;......................................... X_LEFT_FUNCTION: CALL TURNTABLE_LEFT2 CALL DELAY2 CALL DELAY2 CALL DELAY2 CALL DELAY2 JB
CALL STOP RET ;........................................................................ X_RIGHT_FUNCTION: CALL TURNTABLE_RIGHT2 CALL DELAY2 CALL DELAY2 CALL DELAY2 CALL DELAY2 JB
CALL STOP RET ;........................................................................ SHOULDER_DOWN2: SETB SHOULDER_A
RET ;................................................................ SHOULDER_UP2: CLR
SETB SHOULDER_B RET ;............................................................... GRIPPER_OPEN2: SETB GRIPPER_A CLR
CALL DELAY2 CALL DELAY2 CALL DELAY2 CALL DELAY2 CALL STOP RET ;............................................................... GRIPPER_CLOSE2: CLR
SETB GRIPPER_B CALL DELAY2 CALL DELAY2
CALL DELAY2 CALL DELAY2 CALL STOP RET ;............................................................... TURNTABLE_RIGHT2: SETB TURNTABLE_A CLR
RET ;.............................................................. TURNTABLE_LEFT2: CLR
SETB TURNTABLE_B RET ;.............................................................. DELAY2: MOV R1,#2 KK11:MOV R2,#250 KK12:MOV R3,#250 DJNZ R3,$ DJNZ R2,KK12 DJNZ R1,KK11 RET
;............................................................ pos1: mov
ret ;.............................................................. pos2:
ret ;................................................................ pos3: mov
ret ;................................................................ END
CHAPTER 6 FUTURE WORKS This project involves the sorting of objects through colour sensors the future advancements can be done by increasing the efficiency of the colour sensor. The sensor is key component of project which aides in distinguishing the objects. Failing of which may result in wrong material handling. Thus it becomes vital that the sensor had a very high sense of sensitivity and ability to distinguish between colours. Another area of improvement is design of efficient gripper of Digital Image Processing (DIP) is a multidisciplinary science. The applications of image processing include: astronomy, ultrasonic imaging, remote sensing, medicine, space exploration, surveillance, automated industry inspection and many more areas. Different types of an image can be discriminated using some image classification algorithms using spectral features, the brightness and "colour" information contained in each pixel. The Classification procedures can be "supervised" or "unsupervised". With supervised classification, identified examples of the Information classes (i.e., land cover type) of interest in the image. These are called "training sites”. The image processing software system is then used to develop a statistical characterization of the reflectance for each information class. Genetic algorithm has the merits of plentiful coding, and decoding, conveying complex knowledge flexibly. An advantage of the Genetic Algorithm is that it works well during global optimization especially with poorly behaved objective functions such as those that are discontinuous or with many local minima. MATLAB genetic algorithm toolbox is easy to use, does not need to write long codes, the run time is very fast and the results can be visual. The aim of this work was to realize the image classification using Matlab software.
Matlab is a widely used software environment for research and teaching applications on robotics and automation, mainly because it is a powerful linear algebra tool, with a very good collection of toolboxes that extend Matlab basic functionality, and because it is an interactive open environment. The paper presents a toolbox that enables 61
access to real robotic and automation (R&A) equipment from the Matlab shell. If used in conjunction with a robotics toolbox it will extend significantly their application, i.e., besides robotic simulation and data analysis the user can interact on-line with the equipment. Personal experience with this tool shows its usefulness for research applications, but also for teaching projects. With students, using Matlab means taking advantage of the reduced training required to start using it, if compare with other programming environments and languages that can also be used (Microsoft Visual C++ or Visual Basic). An innovative approach for quality sorting of objects such as apples sorting in an agricultural factory, using an image processing algorithm. The objective of the approach are; firstly to sort the objects by their colours precisely; secondly to detect any irregularity of the colours surrounding the apples efficiently. An experiment has been conducted and the results have been obtained and compared with that has been preformed by human sorting process and by colour sensor sorting devices.
Existing sorting method uses a set of inductive, capacitive and optical sensors do differentiate object colour. Advanced mechatronics colour sorting system solution with the application of image processing. Supported by OpenCV, image processing procedure senses the circular objects in an image captured in realtime by a webcam and then extracts colour and position information out of it. This information is passed as a sequence of sorting commands to the manipulator that does pick-and-place mechanism. Extensive testing proves that this colour based object sorting system works 100% accurate under ideal condition in term of adequate illumination, circular objects’ shape and colour. The circular objects tested for sorting are silver, red and black. For non-ideal condition, such as unspecified colour the accuracy reduces to 80%.
CHAPTER 7 CONCLUSION The project works successfully and separates different coloured objects using colour sensor. The colour sensor result was converted chiefly to the command that drive the handling systems which drive the pick and place robot to pick up the object and place it into its designated place. There are two main steps in colour sensing part, objects detection and colour recognition. The system has successfully performed handling station task, namely pick and place mechanism with help of colour sensor. Thus a cost effective Mechatronics system was designed using the simplest concepts and efficient result was being observed. This system is a depicting the prototype of sorting systems which are used in industries.
CHAPTER 8 REFERENCES
 Tsalidis, S., S., Dentsoras, A., J., “Application of design parameters space search for belt conveyor design” Journal of Plant Science, Vol. 10, No. 6, pp. 617-629, 2010. . Huang, T, Wang, P.F., Mei, J.P., Zhao, X.M.,“Time Minimum Trajectory Planning of a 2-DOF Translational Parallel Robot for Pick-and-place Operations” IEEE Computer Magazine, Vol. 56, No. 10, pp. 365-368, 2007. Sahu, S., Lenka, P.; Kumari, S.; Sahu, K.B.; Mallick, B.; “Design a colour sensor: Application to robot handling radiation work”, Industrial. Engineering, Vol. 11, No. 3, pp. 77-78, 2010. . Khojastehnazhand, M., Omid, M., and Tabatabaeefar, A., “Development of a lemon sorting system based on colour and size” Journal of Plant Science, Vol. 4, No. 4, pp. 122127, 2010. . Dogan Ibrahim “Microcontroller Based Applied Digital Control”, International Journal of Science, Vol. 23, No. 5, pp.1000- 1010,2007.
CHAPTER 9 APPENDIX TOPIC NO. •
METHODOLOGY Fig. 2.1 6 •
CONVEYOR SYSTEM Fig 3.1
ROBOTIC ARM Fig3.2
RELAY CIRCUIT WITH ULN DRIVER Fig 4.4
RELAY CIRCUIT Fig 4.3
ULN 2803 DRIVER Fig 4.2
ELECTRONIC MODULE Fig 4.1
GRIPPER Fig 3.3
COLOUR SENSOR Fig 4.5
LED BASED LDR SENSOR Fig 4.6
LDR WITH CELLOPHANE FILTER Fig 4.7
INFRA-RED SENSING UNIT Fig 4.11
OBSTACLE DETECTION (IR BASED) Fig 4.10
INFRA-RED SENSING LOGIC Fig 4.8
COLOR SENSING CIRCUIT Fig 4.8
VOLTAGE CONVERTOR CIRCUIT Fig 4.12