types of robots

1. Types of robots

2. CO-3
Introduction of robotics: Types of robots, Classification, usage, and the
Applications of Robots. Mathematical representations of robots: Position
and orientations of rigid body, Homogeneous transformations,
Representation of joints, Link representation using D-H parameters, Different
kinds of Actuators (Stepper, DC servo and AC motors), Sensors (internal and
external sensors) Common sensors – encoders, tachometers, strain gauge
based force-torque sensors, proximity and distance measuring sensors.

3. 3. Ghosal,A., Robotics: Fundamental Concepts and Analysis, Oxford
University Press, 2nd reprint, 2008.3.
3. Fu,K., Gonzalez, R. and Lee, C. S. G., Robotics: Control, S e n sin
g,Visio n a n d Intelligence¸ McGraw - Hill, 1987.

4. History
• ‘robot’ – 1923 – Czech play R.U.R (Rossum’s Universal Robot -1921)
by Karel Capek
• Slave labour

5. Modern Industrial Robot
1. A PUMA 560 robot (Programmable Universal Machine for Assembly) -
Unimation
2. T3 (The Tomorrow Tool)
-Cincinnati Milacron

10. Robot – definition
• It is an automatic device that performs functions normally belongs to
human or a machine in the form of a human
• It is a re-programmable multi-functional manipulator designed to move
materials, parts, tools or specialized devices through various programmed
motions for the performance of a variety of tasks.

11. Re-programmable
• Re-programmable ---- distinguishes a robot from computer
numerically controlled machine CNC

12. Key component in development of Robot
1. Digital Computer
2. feedback control
Reason for Reduction in growth of robot
1. Inability of robots to perform task that human operator could perform
easily
2. Inability of robots to Avoiding obstacles in a cluttered workspace
3. Inability of robots to Recognizing and manipulating objects- screws, bolts,
nuts..
4. Inability of robots to Adapting and reacting quickly to changes in
environment

13. Late 1980-early 1990 Robots – Blind, deaf &
dump

14. Late 1980-early 1990 Robots – Blind, deaf &
dump
• Sensors and computing resources
1. Robots can sense
2. Quickly process data from sensors
3. Interact intelligently with environment

15. Present day Robots
• Detect the presence or absence of object to be manipulated
• Measure applied forces and moments
• Obtain the position and orientation of objects in its environment
• Variety of end-effectors , hands and grippers – grasp and manipulate
a wide variety of tools and objects
Robot is easier to program, more flexible and more
intelligent

16. Classification of robots based on the
application environment
1. Environment that is hazardous for humans to operate in, or an
environment where the cost of protecting human is very high
Environment not hazardous to human beings but where human
beings are hazardous to the product

17. Examples
• Handling of fuel and radioactive material in nuclear power plant
• Space – satellite
• Underwater operations
• Ultra clean room in the electronic industry

18. Classification of robots based on the
application environment
2. Tasks that are repetitive, back-breaking and also boring for
human beings

19. • Human beings cannot maintain the required accuracy because of the
monotonous and tedious nature of the task
• Spray painting and welding of car bodies
• Loading and unloading of material, parts and tools from other
machines
• Assembly of components – electric motors, computer pheripharals….

20. Classification of robots based on the
application environment
3. Manufacturing of consumer products where the number of items is
not very large and the product or the model is frequently changing

21. • Television sets, cameras and other audio/video consumer products
• Reprogramming the robots to handle different parts of newer models
are easier than expensive re-tooling and changes in the assembly line

22. Star wars

23. LEGO

24. Asimo……………By Honda --------

26. Hanson
Sophia is a social humanoid robot developed by
Hong Kong based company Hanson Robotics.

27. Da Vinci

28. $2 million ……… Rs 14,18,17,000.00 Indian
Rupee

29. • Japan 5,500 - 1980…. 65,000 -1985…… 400,000 – 1995
• Europe
• USA

30. Types of Robots
Classification based on their number of
degrees of freedom/axes
• Translational envelopes :
1.Moving forward and backward on the X-axis. (Surge)
2.Moving left and right on the Y-axis. (Sway)
3.Moving up and down on the Z-axis. (Heave)
• Rotational envelopes :
1.Tilting side to side on the X-axis. (Roll)
2.Tilting forward and backward on the Y-axis. (Pitch)
3.Turning left and right on the Z-axis. (Yaw)
Degrees of freedom indicates the
capability of a robot

33. • 6 DOF --- positioning and orienting an object / Tool
• 5 DOF --- Painting and simple welding

34. Types of Robots
Classification based on its Configuration
1. Cartesian
2. Spherical
3. Cylindrical

35. Cartesian system is one that moves in three, orthogonal axes — X, Y, and Z
1. Cartesian

36. 2. Spherical
• Ball-shaped robot is a mobile robot with spherical external shape
• A spherical shell serving as the body of the robot and an internal driving
unit (IDU) that enables the robot to move .
• Move by rolling over surfaces.
• The rolling motion is performed by changing the robot's center of mass
(i.e., pendulum-driven system)

40. spherical robot also be referred to a stationary robot with two rotary joints
and one prismatic joint which forms a spherical coordinate system

41. 3. Cylindrical
It has 3 axes of movement. Two are linear and one circular

43. • First 3 joints – used to position an object
• 2 or 3 additional joints (wrist joints) – used to orient the tool
• Actuator - device that converts energy into physical motion.
-- electric motors, hydraulic or pneumatic cylinders
• Manipulator- device used to manipulate materials without direct physical
contact by the operator
• Serial Manipulator
• Parallel manipulator

44. Loop in robotics

45. Serial Manipulator
• One fixed end
• A free end – which carries the
end-effector or tool
• No closed loop
Parallel manipulator
• One or more joints fixed to the ground
• One or more closed loop

46. Classification based on the mode of operation
Playback Robot
• A robot is physically taken through each step of the desired motion by an
operator.
• These recorded positions are simply Played back by the robot by an signal when it
required

47. Computer Controlled robot
• The desired motion is obtained from a computer after computations according
to specified algorithms
Intelligent Robot
• It is connected with sensors and processors and is capable of performing tasks –
avoiding obstacles, taking simple decisions based on inputs, learn about the
environments

48. Technology and Hardware of the Robot
1. Mechanical components
2. Actuators
3. Power transmission devices
4. Sensors
5. Electronic Controllers
6. Computer

49. Main Mechanical components
• Links connected by joints
• Various types of bearings
• End effector

51. Actuators
• Links are moved by actuators
• Electric motors – DC / AC servo motor or Stepper motor
• Pneumatic
• Hydraulic cylinders
Motors – low RPM, lightweight, high torque

52. Power transmission devices
Transmission of power and reduce the speed
• Low-backlash gear sets
• Harmonic drives
• Ball screws
Stop / hold the robot
• breaks

56. • stepper motors convert an electrical pulse in to a defined angular movement
called steps. The stepper motors do not require feedback loop to ensure precise
movement.
• servomotor is a closed-loop servomechanism that uses position feedback to
control its motion and final position As the disk rotates, these patterns interrupt
the light emitted onto the photo detector, generating a digital or pulse signal
output.

57. Servo motor
• A servomotor is a rotary actuator or linear actuator that allows for precise
control of angular or linear position, velocity and acceleration

58. • It consists of a suitable motor coupled to a sensor for position feedback.
• It also requires a relatively sophisticated controller, often a dedicated
module designed specifically for use with servomotors.

61. • A servomotor is a closed-loop servomechanism that uses position feedback
to control its motion and final position.
• The input to its control is a signal (either analogue or digital) representing
the position commanded for the output shaft.
• The motor is paired with some type of position encoder to provide position
and speed feedback. In the simplest case, only the position is measured.
• The measured position of the output is compared to the command
position, the external input to the controller. If the output position differs
from that required, an error signal is generated which then causes the
motor to rotate in either direction, as needed to bring the output shaft to
the appropriate position.
• As the positions approach, the error signal reduces to zero and the motor
stops

63. Sensors
-- Measures rotation and translation at joints for feedback control
• Angular rotation – optical encoders
• Angular velocity -- tachometer
• Translation and Linear velocity – LVDT (Linear variable Transformer) and
video camera
• Force at the end effector / links – Force-torque sensor – strain gauge

64. Electronics Controllers
• Microprocessors
-- A/D , D/A, Memory…
Measured signal – 5v
I/P actuators - 12 or 24V
Driver – to amplify

65. Computer and Software
Set 1
• Performs the task of controlling the actuators in a robot
Set 2
• Supervisory or a master computer where application programs can be
developed and stored, fault detection, diagnosis and corrective actions can
be taken or where high-level task planner or an expert system can reside

66. Basic Principles in Robotics
Interdisciplinary subjects
• Kinematics
• Dynamics
• Control
• Sensors

67. Kinematics
• Motion of rigid bodies in a 3D space
• 6DOF – 6 independent parameter to be fully specified
3 parameter – (position– point on the end effector)
3 parameter – orientation
6DOF – 6 independently actuated joints
---Study the functional relationship b/w the motion at the joints and the
motion of the end-effector without reference to the cause of the motion

68. Direct kinematics problem
The motion at the end effector for a given motion at the joints
Inverse kinematics problem
The motion at the joint for a required motion of the end effector

69. Dynamics
• Study the motion of the links and the end-effector under the
action of external forces and torque from the actuators

70. Control
• Position control
• Control the force which the robot applied on the environment
INTELLIGENT – interacting with the external environment and taking
simple decision they need to be equipped with sensors
SENSORS - enable the robot to apply the correct amount of force to
grip delicate objects.

71. Master Slave Manipulator Systems..