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.
the part. This technique also used to measure oscillators to =Hydraulic robot – good for heavy
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.
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
GENERAL KNOWLEDGE OF
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
process by means of programmed commands or plastic that and sudden
combined with automatic feedback control to transfer light pressure changes is needed (shock proof
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
THEORY AND APPLICATION SIGNAL CONDITIONING AND
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
=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)
1. has 2 unit - transmitter unit
=The sensor consists of a transmitting and
=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”.
=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
Block diagram of Capacitive Proximity sensor