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									Vision system application ;                                                                              ROBOTIC AND ITS APPLICATIONS
Part identification – vision system store data      Type of         difference         vision            Robots:
for different parts in memory and use the data      sensor                                               =Robots are very good for repetitive
to distinguish between parts as they enter the      proximity       1.Two major        -electronic       tasks such as moving and positioning
work cell.                                                                                               parts between devices and products. Fast
Part location – vision technology allows the        sensor          types of           sensors that      and accurate.
automation system to locate randomly placed                         proximity          indicate the      =3 types of robots: Electric Robots,
parts entering the work cell.                                       detectors are      presence of an    Pneumatic Robots and Hydraulic
Part orientation – vision system supplies the                       (i) inductive      object without    Robots.
orientation information and the data are used                       and (ii)           making            =Electric robot – very versatile, often
to drive the robot gripper into the correct                         capacitive         physical          used for painting and welding because it
orientation for part pickup.                                                                             is fast & accurate. More expensive than
Part inspection – vision system are used to                                                              pneumatic robot.
check parts for dimensional accuracy                Ultrasonic      1. electrostatic                     =Pneumatic robot – good for simple
(e.g.diameter of a part) and geometrical            Sensor          – uses                               positioning tasks, it is inexpensive
                                                                                       sensors use a
integrity (e.g. number of holes).                                   capacitive                           compare to electric robot and pneumatic
 Part finding – the system uses two or more                         effects. It has                      robot. But the usage is very limited in
cameras to measure the X, Y, Z location of                                             frequency         some ways.
                                                                    longer ranges
the part. This technique also used to measure                                          oscillators to    =Hydraulic robot – good for heavy
                                                                    and wider
and calculate the cross- sectional area of parts.                                      generate          applications, fast and can move
                                                                    bandwidth, but                       smoothly. Also good for dangerous
Vision System Operation:                                                               frequencies
-Vision systems look at contrast to make                            is more                              applications.
                                                                                       above 20KHz.
decisions. A camera used to capture the image                       sensitive to                                 Robot Integration:
and the it will be analyzed by the computer.                        factors such as                      =Two methods to control the robot: 1)
-The vision processing board looks at each                          humidity                             Using teach pendant        2) Using special
pixel to determine its brightness level. (Gray      Hall-Effect                                          programmed language
Level)                                                              1.This sensor is   -This sensor      =Robots have digital inputs and digital
-The computer then will look at all areas of                        a flat             detects the       outputs which are easily connected to
the object and assign brightness levels, which                      rectangular        presence of a     control devices. (e.g. PLCs, Computer)
represent contrast to each.                                         piece of P-type    magnetic field    =Most robots cells wait for an input to
Type of Vision System:                                                                                   tell robot what to do, it then forms a task
Binary system – lowest in cost, easiest to use                                                           and sends back an output signal to a cell
& do basic visual inspection                                        called a Hall                        controller.
 Gray scale imaging – using 256 levels of                           generator –                          =The exchanges process of input and
black and white, more accurate than binary                          made from                            outputs between devices is called
system, expensive than binary & sometimes                           indium                               “Handshaking”
has longer processing times.                                        arsenide (In                         THEORY OF BOURDON
Color processing – uses information from                                                                 TUBE,SPRING,BELLOWS,DIAPHRAGM)
red, blue and green parts of the color                                                                    =The Bourdon tube is a hollow tube
                                                    Photoelectric                                        with an elliptical cross section. When a
spectrum to detect and differentiate shades of                      1.Emitters will    -Optical
color relevant (e.g. in food industry and           Sensor                                               pressure difference exists between the
                                                                    produce light      sensors
pharmaceutical), more expensive than the first                                                           inside and outside, the tube tends to
                                                                    beams in the       require both a
two types, but they offer unique advantages.                                                             straighten out and the end moves. The
                                                                    visible and        light source      movement is usually coupled to a needle
AUTOMATION                                                          invisible          (emitter) and     on a dial to make a complete gauge.
-Automation is used to describe a wide variety                      spectrums          detector          =The pressure acts directly on the piston
of systems in which there is a significant                          using LED and                        and compresses the spring. The position
substitution of mechanical, electrical, or                          laser diodes                         of the piston is directly related to the
computerized action for human effort and             Fiber                             -Fiber optics     pressure. A window in the outer case
intelligence.                                                       -The basic                           allows the pressure to be indicated. This
                                                     Optics                            are transparent   type is usually used in hydraulics where
-In general usage, automation can be defined                        structure of an
as a technology concerned with performing a          Sensors                           stands of glass   the ability to withstand shock, vibration
                                                                    optical fiber
process by means of programmed commands                                                or plastic that   and sudden
                                                                    (OF) consists
combined with automatic feedback control to                                            transfer light    pressure changes is needed (shock proof
                                                                    of three
ensure proper execution of the instructions.                                           to and from       gauge).
                                                                    different                            = If the bellows is encapsulated inside an
The resulting system is capable of operating                                           such locations
without human intervention.                                         layers: the                          outer container, then the movement is
-Automated System: a collection of devices                          core, the                            proportional to the
working together to accomplish tasks or                             cladding and                         difference between the pressure on the
produce a product. (e.g.. an Automobile and                         the coating or                       inside and outside. Bellows and single
Home burglar alarm system)                                          jacket .                             capsules are used in many instruments.
Purpose of Automation                                                                                    They are very useful for measuring small
-To increase productivity and reducing costs.                                                            pressures.
-To Increase quality and flexibility.                                                                    =These are similar in principle to the
-Replace human intervention for hazardous                                                                capsule but the diaphragm is usually
operations )                                                                                             very thin and perhaps made of rubber.
-Increased emphasis on flexibility and                                                                   The diaphragm expands when very small
convertibility in the manufacturing process.                                                             pressures are applied. The movement
                                                                                                         is transmitted to a pointer on a dial
                                                                                                         through a fine mechanical linkage
OF,ULTRASONIC,HALL-EFFECT                               PROCESSING:
                PROXIMITING                              A basic instrument system consists of three
-=Unshielded sensors do not have this metal                 elements:
band, therefore they can be side sensitive.
=Shielded construction includes a metal band            i SENSOR or INPUT DEVICE
which surrounds the ferrite core and coil               ii SIGNAL PROCESSOR
arrangement. It will direct the electromagnetic         iii RECEIVER or OUTPUT DEVICE
field to the front of the sensor.
1.Oscillating signal from oscillator stage is           Figure1: Block diagram of basic instrument
fed into the demodulation section. The                  system
demodulator is a filtered rectifier which
converts the AC signal into a DC voltage
                Capacitive sensor
=As an object approaches, the oscillator
begins to oscillate. The closer the object the
faster oscillation become.
=This situation will cause the Schmitt trigger
to switch to its higher voltage level.             Most modern analogue equipment works on the
=The positive potential forward biases the         following standard signal ranges.
base emitter junction of the NPN transistor,       =Electric (4 to 20 mA)
causing it to turn ON.                             =Pneumatic (0.2 to 1.0 bar)
                  Ultrasonic Sensor
       1. has 2 unit - transmitter unit
                         -receiver unit
=The sensor consists of a transmitting and
receiving devices.
=The basic principle for this sensor is that if
sound transmitted through air, a portion of it
will be reflected.
=The reflected signal is called an “echo”.
       Hall-Effect sensor
=When a power source supplies a constant
current to the sensor, positively charged
carriers flow uniformly through the material
when a magnetic field is not present
=At this condition, the voltage at the output is
=When an electromagnet or a permanent
magnet is present near the semiconductor
material, the magnetic field from the
electromagnet target will deflect the positive
charged carriers to one side of the
semiconductor material by an effect called
Lorentz force
Block diagram of Capacitive Proximity sensor

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