This document provides an overview of industrial robots and various sensors used by robots. It discusses how George Devol applied for the first robotics patents in 1954 and how industrial robots are automatically controlled manipulators that can operate in three or more axes. It then summarizes several types of sensors like load sensors, proximity sensors, pressure sensors, heat sensors, and smell sensors; describing their basic functions and applications in areas like manufacturing, aviation safety systems, and pollution detection.

1. -By Nitesh Chowdhury

2.  An industrial robot is defined by ISO as an
automatically controlled, reprogrammable,
multipurpose manipulator programmable in three or
more axes.
 Typical applications of robots include welding,
painting, assembly, pick and place, packaging and
palletizing, product inspection, and testing, all
accomplished with high endurance, speed, and
precision.

3.  PALLETIZING FOOD PRODUCTS
FOUNDRY

4. HISTORY
 George Devol applied for the first robotics patents in
1954 to transfer objects from one point to another.
 In 1969 Victor Scheinman at Stanford University
invented the Stanford arm, an all-electric, 6-axis
articulated robot designed.

5.  The setup or programming of motions and sequences
for an industrial robot is typically taught by linking the
robot controller to a computer.
 A robot is either completely operated by a human or
de-energized first, placed in a required position and
then the controller does the rest.
 It means that a robot will always require employment
of a human.

6.  Hence robots were first used only for jobs either
tiresome for humans or hazardous to their health.
 The requirement of automation lead to invention of
sensors.
 Here are some of the sensors generally used:-

7. LOAD SENSOR
 Load sensors are electromechanical transducers that
translate force or weight into voltage.
 For example: the amount of gas for deploying the
airbag and the energy absorbing (EA) load of the seat
belt are adjusted depending on the weight of the
occupant. For this purpose, load sensors are needed
for measuring the weight of the occupant sitting on
the seat.

8.  A load sensor for converting a force or a weight into an
electrical signal is generally formed by attaching a
plurality of strain gauges to a load-sensitive element.
 The change in voltage produces, in the read-out
instrumentation, a repeatable deflection or indication
that can be calibrated directly in terms of the load
applied to the load transducer.

9. PROXIMITY SENSOR
 A proximity sensor is a sensor able to detect the
presence of nearby objects without any physical
contact.
 It emits an electromagnetic or electrostatic field, or a
beam of electromagnetic radiation and looks for
changes in the field or return signal.
 The object being sensed is often referred to as the
proximity sensor's target.

10.  The maximum distance that this sensor can detect is
defined "nominal range".
 Proximity sensors can have a high reliability and
long functional life because of the absence of
mechanical parts and lack of physical contact between
sensor and the sensed object.
 A proximity sensor adjusted to a very short range is
often used as a touch switch.

11.  A proximity sensor is divided in two halves and if the
two halves move away from each other, then a signal is
activated.
 A proximity sensor can be used in windows, and when
the window opens an alarm is activated.

14. TYPES OF SENSORS
 Inductive
 Capacitive
 Capacitive displacement sensor
 Eddy-current
 Magnetic, including Magnetic proximity fuse
 Photocell (reflective)
 Laser rangefinder

15.  Sonar (typically active or passive)
 Radar
 Doppler effect (effect not a sensor)
 Passive thermal infrared
 Passive optical (such as charge-coupled devices)
 Reflection of ionizing radiation

16. APPLICATION
 Car bumpers that sense distance to nearby cars for
parking
 Position of work piece
 Ground proximity warning system for aviation safety
 Vibration in machinery
 Sheet break sensing in paper machine.
 Anti-aircraft artillery
 Mobile phones

17. PRESSURE SENSOR
 A pressure sensor measures pressure, typically of gases or
liquids.
 A pressure sensor usually acts as a transducer; it generates a
signal(electrical) as a function of the pressure imposed.
 Some pressure sensors, such as those found in some traffic
enforcement cameras, function in a binary (on/off)
manner, i.e., when pressure is applied to a pressure sensor,
the sensor acts to complete or break an electrical circuit.
These types of sensors are also known as a pressure
switch.

19. TYPES
 Absolute pressure sensor-measures the pressure
relative to perfect vacuum pressure
 Gauge pressure sensor-measure the pressure relative
to a given atmospheric pressure at a given location.
 Vacuum pressure sensor-measure pressure less than
the atmospheric pressure at a given location.

20.  Differential pressure sensor-measures the
difference between two or more pressures introduced
as inputs to the sensing unit, for example, measuring
the pressure drop across an oil filter.
 Sealed pressure sensor-same as the gauge pressure
sensor except that it is previously calibrated by
manufacturers to measure pressure relative to sea level
pressure.

21. SENSING TECHNOLOGY
 Piezoresistive strain gauge-Uses the piezoresistive effect of
bonded or formed strain gauges to detect strain due to applied
pressure.
 Capacitive-Uses a diaphragm and pressure cavity to create a
variable capacitor to detect strain due to applied pressure.
 Electromagnetic-Measures the displacement of a diaphragm by
means of changes in inductance (reluctance), LVDT, Hall Effect,
or by eddy current principle.
 Piezoelectric-Uses the piezoelectric effect in certain materials
such as quartz to measure the strain upon the sensing
mechanism due to pressure.

22.  Optical-Uses the physical change of an optical fiber to
detect strain due to applied pressure.
 Potentiometric-Uses the motion of a wiper along a
resistive mechanism to detect the strain caused by
applied pressure.
 Resonant-Uses the changes in resonant frequency in a
sensing mechanism to measure stress, or changes in
gas density, caused by applied pressure.

23.  Thermal-Uses the changes in thermal conductivity of
a gas due to density changes to measure pressure.
 Ionization-Measures the flow of charged gas particles
(ions) which varies due to density changes to measure
pressure.

24. APPLICATIONS
 Pressure sensing-to measure pressure.
 Altitude sensing-in aircraft, rockets, satellites,
weather balloons, and many other applications.
h=(1-(P/Pref)^.190284)X145366.45 ft
 Flow sensing-use of pressure sensors in conjunction
with the venturi effect to measure flow.

25.  Level / depth sensing-used to calculate the level of a
fluid. P=pgh
 Leak testing-used to sense the decay of pressure due
to a system leak

26. HEAT SENSOR
 There are three kinds of heat sensors used for
industrial robots viz Resistance, Thermocouple, IR.
 Resistance thermometer have a defined resistance
value at 0 °C which alters, depending on temperature.
This alteration is presented as temperature value.

27.  Thermocouples consist of two different metal wires
which are welded together in one point. When the
weld spot is heated, a thermal voltage is generated at
the open ends of the wires which provides the
temperature measurement.
 IR temperature sensor is used to when accurate
measurement is required without contact.

29. SMELL SENSOR

30.  One of the latest inventions in the world of robotics is
the smell sensor.
 A University of Tokyo group of researchers, led by
bioengineer Shoji Takeuchi, has made an electronic
sensor capable of smelling gases.
 It uses genetically engineered frog cells.

31.  It was revealed in a US scientific journal on August
28th 2010, and is supposed to be used to design better
machines to detect polluting gases in the atmosphere
 Previous smell sensors were based on quartz rods,
which vibrate when a substance binds to them.

32.  The gases are distinguished by their molar masses,
which can be similar for molecules with different
structure, thus relatively often triggering a false
positive.
 Genes of several insects (the silk moth, diamondback
moth and fruit fly), injected into African clawed frog
Xenopus laevis eggs, allowed them to produce
relatively inexpensive and useful sensors

33. QUESTIONS????????

34. THANK YOU…….!!!