PPT includes fundamentals of robotic sensors and their applications in robots as well as in industrial automation.

1. Pankaj Kumar Pundir
Educator
er7pankaj@gmail.com
+91-9915149680
• Introduction
• Types of Sensors in
robots
• Exteroceptors or
External Sensors
• Tactile Sensors
• Proximity Sensors
• Machine Vision
Sensors
• Velocity Sensor
ROBOTIC
SENSORS
By :
UNIT - 3

2. Introduction
Without sensors a robotic device would not be able to discern anything about current
surroundings.
It became a simple machine , and you know a machine can only run on predefine logic
and it can not sense any uneven situation hence accidents can happen or product
quality may suffer.
Need of sensors in robots.
A human being with his intuition and learning capability
understand language, reasons and solve problems.
Imparting all these intelligent characteristics to the machine
is really difficult.
In automated manufacture attempts have been made to
design machines and robots that can perform tasks
intelligently.
Installing Sensors to robots/machines make systems
intelligent.

3. Sensors in Robots
Sensor is used to measure some feature of the world , Such as light, sound, or
pressure and convert that measurement into electrical signals, usually a voltage or
current.
The output of given sensor can easily be converted into other electrical
representations.
Sensing includes activities such as seeing, hearing, touching, smelling and measuring
distance.
LETS GUESS………..name of some sensor may be used in Robots

4. Classification of Sensors in ROBOTS
A wide variety of devices are used by robots to obtain information. They include not
only transducers for physical quantities such as microphones for sounds, but also
data processing input devices such as keyboard for textual information and
specialized sensors. Sensors in robots are classified as :-
 Exteroceptors or External Sensors (for the measurement of robot’s
environment parameters)
 Proprioceptors or Internal Sensors (for the measurement of robots
internal parameters)

5. Exteroceptors or External Sensors
Exteroceptors are sensors that measure the
positional or force-type interaction of the robot
with its environment.
External Sensors categorized as :-
 Contact Sensors
 Non Contact Sensors

6. Contact Sensors
Contact sensing is one of the most basic requirement for any manipulator interacting
physically with the environment in a non-structured manner. It is the ability of the
robot to determine the shape, size, weight, or even the surface texture of an object
by touching it.
 Searching –detecting a part by sensitive touch sensors on the hand exterior
without moving the part.
 Recognition –determining the identity, position, and orientation of a part,
again without moving it, by sensitive touch sensors with high spatial
resolution.
 Grasping –acquiring the part by deformable, roundish fingers, with sensors
mounted on their surfaces.
 Moving –placing, joining, or inserting a part with the aid of force sensors.
The functions of contact sensors in controlling manipulation may be classified into
the following basic material handling and assembly operations:

7. Types of Contact Sensors
Tactile Sensors:-
Tactile sensors are used to identify and to control directly the interaction between
the robot end effector and the environment.
Tactile sensors find their use in various locations of a robot system including joints
between the robot links, wrist between arm and end effector, the finger points and
the fingertip.
Important for assembly and for quality.
For example-
 Pressure sensors used for part orientation and gripping force control.
 Piezoelectric sensors for continuous pressure.

8. Tactile Sensors can be classified as
Touch Sensor
Touch sensors produce a binary output signal.
Touch sensors may be mounted on the outer and inner surface of each finger.
Outer mounted sensors may be used to search for an object and possibly determine
its identity, position and orientation.
Inner mounted sensors may be used to obtain information about an object before it
is acquired and about grasping forces and workpiece slippage during acquisition.
 Microswitch are the most commonly used and least
expensive kind of touch sensor with either turns on or off
as contact is made.

9. Robotic Platform Employing Bumper Coupled to Touch Sensor

10. Tactile Sensors can be classified as
Force/Stress Sensors
Force/torque sensors measure the amount of force and torque exerted by the
mechanical hand.
The interaction forces and torques, which appear during mechanical assembly
operations at the robot hand level, can be measured by sensors mounted on the
joints or on the manipulator wrist.
Individual stress sensors usually respond only to force in one direction on them. However, combination
of two or more can report forces as well as torques in two or three directions.
Strain gauges are used to make force sensors, torque sensors and sensors that can
measure both kinds of stress simultaneously.

11. Application of Tactile sensors in Robotics
 Simplest type of tactile sensor is a gripper that is equipped with an array of
miniature micro switches. (It can use to determine the presence or absence of an object at a
particular point or array of points)
 Advance type of tactile sensor uses arrays of pressure-sensitive piezoelectric
material. This material conducts electrical current when stressed. More pressure
applied to the material, the more electrical current is produced. (This is essential
where the gripper is handling delicate, fragile objects so that the robot will not apply too much
force and crush the object it is holding)

12. Fundamentals of Machine Vision
Machine Vision is the use of a computer to acquire visual information
and/or extract image information for purposes of data storage or
automatic decision making.
Machine Vision
+ =

13. Working
A vision sensor (camera) converts the visual information to electrical
signals, which are then sampled and quantized by a special computer
interface electronics yielding a digital image.
A general vision system consists of a
• Light Source
• Image Sensor
• Image Digitizer
• System Control Computer
• Output

14. Machine Vision Sensor

15. Application of Machine Vision Sensor
Industrial Application:-
• Motion/ Robot Guidance
• Defect/ Flaw Detection
• Inspection/ Grading/ Sorting
• Identification/ Verification
• Data Acquisition
• Measurement/ Gauging

16. Velocity Sensors
Used to estimate the speed with which a manipulator is moved.
The DC tachometer is one of the most commonly used devices for
feedback of velocity information.

17. Proprioceptors or Internal Sensors
Encoder:-
Encoders are digital position transducers, which are the most convenient
for computer interfacing.
Strain gauge:-
Used to estimate the flexibility of the robots mechanical structure .
Mounted on specially profiled shafts are also used to measure the joint
shaft torques.

18. References
https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.globalspec.com%2Flearnmore%2Fvideo_imaging_equipment%2
Fmachine_vision_inspection_equipment%2Fvision_sensors&psig=AOvVaw2jn_AU-
oZU9amsr5E10pWE&ust=1585113824466000&source=images&cd=vfe&ved=0CAIQjRxqFwoTCODWhqOvsugCFQAAAAAdAAAAA
BAD
Book – Industrial Automation & Robotics –by AK Gupta, SK Arora
https://www.google.com/images

19. THANK-YOU