shashank soni sensors presentation
TRANSCRIPT
PRESENTATION ON
SENSORS
PRESENTED BY:
SHASHANK SONI
13MT07IND016
M.Tech (Industrial Engg), Sem II
What is a Sensor?
A device that measures a physical variable (e.g. force, pressure, temperature, velocity, flow rate, etc.)
And converts the physical quantity into another form
Which can be read by an observer or by an instrument.
The most common conversion is to electrical form as the converted signal is more convenient to use and evaluate.
General Electronic Sensor• Primary Transducer: changes “real world” parameter into electrical signal
• Secondary Transducer: converts electrical signal into analog or digital values
Typical Electronic Sensor System
usable
valuesreal
worldanalog
signal
primary
transducer
secondary
transducer
sensor
microcontrollersignal processing
communication
sensor
input
signal
(measurand)sensor data
analog/digital
network
display
Desirable features of sensors
Accuracy
Precision
Operating range
Speed of response
Calibration
Reliability
Cost and ease of operation
Resolution
Accuracy vs. Precision
Precision without accuracy
Accuracy without precision
Precision and accuracy
internal information
What is the angle of my arm?
Why Sensors are Required?
Where am I?
localization
?
Why Sensors are Required?
Will I hit anything?
obstacle detection
Why Sensors are Required?
Autonomous material handling
Where are the forkholes?
Why Sensors are Required?
Where is the face?
Face detection & tracking
Why Sensors are Required?
Sensors used in Robotics
The sensors used in robotics include a wide range of devices which can be divided into following categories:
Tactile Sensors
Proximity and Range sensors
Miscellaneous sensors and sensor based systems
Machine vision systems
Tactile Sensors Tactile sensors are devices which indicate contact
between themselves and some other solid object.
Tactile sensing devices can be divided into two classes: Touch sensors and Force sensors.
Touch Sensors
force voltagemeasurement
electrical flow
a simpleswitch
• Touch sensors provide a binary output signal which indicates whether or not contact has been made with the object without regard to the magnitude of the contacting force.
Force Sensing
• Force sensor (also known as stress sensor) indicate not only that contact has been made with the object but also the magnitude of the contact force between the two objects.
Metal foil strain-gauge based (load cell) Good in low frequency response
High load rating
Resolution lower than piezoelectricity-based
Rugged, typically big size, heavy weight
Force Sensing
Piezoelectricity based (force sensor)
lower cutoff frequency at 0.01 Hz
can NOT be used for static load measurement
Good in high frequency
High resolution
Limited operating temperature (can not be used for high temperature applications)
Compact size, light
Proximity and Range Sensors
Proximity sensors are devices that indicate when one object is close to another object.
Some of these sensors can also be used to measure the distance between the object and the sensor, and these devices are called Range sensors.
Range sensors would be useful for determining the location of an object(e.g., the work part) in relation to robot.
Types of Proximity and Range Sensors
Eddy Current Detectordevice that emits an alternating magnetic field at the tip of a probe, which induces eddy currents in any conductive object in the range of the device.
Photometric sensor
used to sense light. category includes photocells , photoelectric transducers ,photo tubes, phototransistor and photoconductors. Can be used to indicate presence or absence of an object.
Optical Pyrometer
device used to measure high temperatures by sensing the brightness of an object’s surface. Can be used to indicate presence or absence of an object.
Vacuum Switches
device used to indicate negative air pressures. Can be used with a vacuum gripper to indicate presence or absence of an object.
Miscellaneous Sensors and Sensor Based Systems
The miscellaneous category covers the remaining types of sensors that might be used for interlocks and other purposes in manufacturing work cells.
This category includes devices with the capability to sense variables such as temp., pressure, fluid flow, and electrical properties.
Types of Miscellaneous Sensor
• Ammeter: Electrical meter used to measure electrical current.
• Linear variable differential transformer: Electromechanical transducer used to measure linear or angular displacement.
• Ohmmeter: used to measure electrical resistance.
• Potentiometer: Electrical meter used to measure voltage.
Types of Miscellaneous Sensor
• Piezoelectric accelerometer: sensor used to indicate or measure vibration.
• Pressure transducer: Various transducers used to indicate air pressure and other fluid pressures.
• Thermistor : device based on electrical resistance used to measure temperatures.
• Thermocouple: used to measure temperatures. Based on the principle that a junction of two dissimilar metals will emit an emf which can be related to temperatures.
Machine Vision System
Vision sensors: Advanced sensor system used together with pattern recognition and other techniques to view and interpret events occuring in the robot workplace.
Magnetic Field Sensor
Magnetic Field sensors are used for power steering, security, and current measurements on transmission lines
Hall voltage is proportional to magnetic field
x x x x x x
x x x x x x
x x x x x x
+ + + + + + + + + + + + + + +
- - - - - - - - - - - - - - -
I (protons) +
VH
-B
tqn
BIVH
Ultrasonic Sensor
Ultrasonic sensors are used for position measurements
Sound waves emitted are in the range of 2-13 MHz
Sound Navigation And Ranging (SONAR)
Radio Detection And Ranging (RADAR) –ELECTROMAGNETIC WAVES
15° - 20°
Applications of Sensors in Manufacturing
Distance sensing
Contour Tracking
Machine Vision / Pattern recognition
Machine diagnosis
Process Parameter sensing
Safety monitoring
Parts inspection for quality control
Distance Sensing
• Sensors for such application are of two types,either contact type or non contact type.
•Contact type sensors are like dial gauge, gaugeblocks, pins, etc. However these sensors have alimitation of wear and tear, and are not verycommonly used.
•Non contact types may be inductive, acoustic,capacitive or optical sensors.
Contour tracking:
This is a kind of scanning process and is performed by using electrical sensors such as inductive and capacitive ones and optical sensors mostly laser based scanners.
Machine Vision:Here also tactile arrays and ultrasonic scanning serve some useful purpose. Besides optical systems with binary vision, grey level sensing and stereovision are widely used.
Machine Diagnosis:
Well known sensors are used to measure forces, torque, strain, frequency and a lot of other indirect diagnostic data.
Process Parameters Monitoring:
Parameters such as pressure, force, speed, temperature, fluid levels, chemical composition and pH value data are measured in different environmental conditions.
END OF PRESENTATION