Electrical

1. Ch-1
Introduction to robotics
 Outline
 Robotics History & Automation
 Robot application
 Robotic system
 Kinematic arrangement of manipulator
 Rigid body motion and Transformation of coordinates

2. Robotics History
 Early Vision
Aristotle writes:-
“If every tool, when ordered, or even of its own accord, could do the work that
befits it... then there would be no need either of apprentices( learner) for
the master workers or of slaves for the lords.”
Automata: water clocks, mechanical animals, mechanical orchestra etc.
Leonardo's robot (1495):-
 Leonardo Da Vinci's one of human
like robot(humanoid) mechanically
automated machine for knights.

3. Cont...
Jacques de Vaucanson (1738):
 The Tambourine Player and The
Digesting Duck is considered his masterpiece.
The notion of “Robot” (1921):
Robot” is coined from Czech word
“robota” ;“Robota” means labor
(Karel Capek’s writes)

4. Three Laws of Robotics
 Formulated by Russian writer Isaac Asimov
1. A robot may not harm a human being
2. A robot must obey the orders given to it
by human beings
3. A robot must protect its own existence

5. Definition of robot
 In 1980, the Robot Institute of America (RIA) came up
with the following definition:-
 A robot is a reprogrammable, multifunctional
manipulator; designed to move material, parts, tools, or
specialized devices
 possess certain anthropomorphic characteristics
 mechanical arm
 sensors to respond to input
 Intelligence to make decisions

6. Robotics applications
 Industrial (automation)
 Service areas
Industrial robots
 In a simple phrase, industrial robotics refers to the
study, design and use of robots for manufacturing.
 Typical applications of industrial robots include welding,
painting, ironing, assembly, palletizing, product
inspection, and testing.

7. Why Robot Application?
 Need to replace human labor by robots
 Work environment hazardous for human beings
 Repetitive tasks
 Boring and unpleasant tasks
 Multi shift operations
 Infrequent changeovers
 Performing at a steady pace
 Operating for long hours without rest
 Responding in automated operations
 Minimizing variation

8. Service robotics
 It comprises everything that is not in industrial
robotics, and reflects the distinction between
the manufacturing and service sectors.

9. Robotic Systems
 An overall robotic system

10. Components of a Robot
 Manipulator / Rover : This is the main body of the Robot
and consists of links, joints and structural elements of the
Robot.
 End Effector :The tool, gripper, or other device mounted
at the end of a manipulator, for accomplishing useful
tasks. Grippers are generally used to grasp and hold an
object and place it at a desired location.

11. Cont…
 Actuator :actuator is a mechanism used to drive the
processor to allow it to move to a predetermined point.
 Sensors : Sensors are used to collect information about
the internal state of the robot or to communicate with
the outside environment.
 Controller :Controller function as the brain of the robot
 Robots have controller that are run by programmed set of
instruction written in code.
 The controller receives data from the computer, controls
the motions of the actuator and coordinates these
motions with the sensory feedback information.

12. Degrees of Freedom
 The degrees of freedom of a rigid body is defined as the
number of independent movements it has.
 DOF = number of independently driven joint
Robot Links and Joints

13. Common Kinematic Arrangements Of
Manipulators
1. Articulated manipulator (RRR)
 The articulated manipulator is also called a revolute, or
anthropomorphic manipulator. e.g ABB IRB1400

14. 2. Spherical Manipulator (RRP)
 By replacing the third or elbow joint in the revolute manipulator by a
prismatic joint one obtains the spherical manipulator

15. 3. SCARA Manipulator (RRP)
 The SCARA arm (for Selective Compliant Articulated Robot for Assembly), it
is quite different from the spherical manipulator in both appearance and
in its range of applications. The SCARA has z0, z1, and z2 mutually
parallel.

16. 4.Cylindrical Manipulator (RPP)
 The first joint is revolute and produces a rotation about the base. The
second and third joints are prismatic and produces translational motion.

17. 5.Cartesian manipulator (PPP)
 A manipulator whose first three joints are prismatic is known as a
Cartesian manipulator.

18. Reference Frames
 World Reference Frame which is a universal coordinate frame, In this case
the joints of the robot move simultaneously.
 Joint Reference Frame In this case each joint may be accessed individually
and thus only one joint moves at a time.
 Tool Reference Frame which specifies the movements of the Robots hand
relative to the frame attached to the hand.

19. Work Envelope concept
 Depending on the configuration and size of the links and wrist joints,
robots can reach a collection of points called a Workspace.
 Workspace may be found empirically, by moving each joint through
its range of motions and combining all space it can reach and
subtracting what space it cannot reach.
Rigid body motion and Coordinate transformation
 Robot manipulation implies movement in space
 The relationship between objects as well as objects and manipulators can be
described based on
 Vectors
 Transformation matrices and coordinate system

20. Vectors
 Vectors are denoted by lowercase bold letters like: v, u,…
 In three-dimensional space , a vector v is considered as column matrix
of the following form:
Vector operations
 The scalar product

21. Cont…
 vector product
Cartesian coordinate systems

22. Cont…
 Basis vectors of an orthonormal coordinate system (orthonormal (unit
length vectors) satisfy the following equations
 Any coordinate system A represented by matrix using orthonormal units

23. Coordinate transformations
 The goal of this section is to define the relationship between two
coordinate systems in 3D space
 Coordinate systems are required for describing position/movement

24. Cont…
 The orthonormal vectors of related coordinate system {B} with
respect to {B} are expressed by:
 while related to {A} these vectors can be written in the form:

25. Point Transformations
 How to determine the position of a point which is known in terms
of one coordinate system with respect to the new coordinate
system defined afterward

26. Cont…
 The following vector equation can be written from the triangle

27. Cont…
 So the above equation will be
 Homogenous transformations matrices
 allow us to represent affine transformations by a matrix operation
 Affine transformation is a combination of single transformations such as
translation or rotation
 Homogenous coordinates embed three-dimensional space R3 into P3, the
three-dimensional projective space, which is R4.

28. Cont…
 homogenous coordinates allow each point (x*, y*, z*) to be represented by
any of an infinite number of four dimensional vectors:
 Using the homogenous coordinates, transformation equation above can be
represented in the

29. Cont…
 Transformation equation can be written in simpler form:
 Transformation matrix encompasses information about the rotation
between two coordinate systems as well as information about the
distance between their origins.

30. Compound transformations
 The task is to determine the coordinates of point 1 with respect to
coordinate system {A}

31. Cont…
 the problem can be solved in two steps
 First, the coordinates of point 1 with respect to the coordinate
system {B}
 the coordinates of point 1 with respect to the coordinate system
{A} are:
 Combining above equations

32. Standard transformations
 The relationship between coordinate
systems will be defined in terms of rotations
about the x, y or z axes

33. Cont…

34. Example