Unit1 my preparation

CONTENTS
• Definition of robot
• Origin of robot
• Asimov’s Law
• Various generation of robot
• Different types of robot
• Dynamic stabilization of
robots 2

WHAT IS THE DEFINITION OF A 'ROBOT'?
“A reprogrammable, multifunctional manipulator
designed to move material, parts, tools, or
specialized devices through various programmed
motions for the performance of a variety of
tasks" Obviously, this was a RIA in 1969:
Webster says: An automatic device that performs
functions normally ascribed to humans or a
machine in the form of a human.
S A M P A T H . K A P / E E E - D A C E 3

THE WORD ROBOT COMES FROM
1. The word 'robota' was coined by the
Czech playwright Karel Capek
(pronounced "chop'ek") from the Czech
word for forced labor or serf. )”
“Rossum’s universal Robot”(RUR in 1921).
Karel Capek

WHO IS HE?

ISAAC ASIMOV’S
The word "robotics" also comes from science fiction -
"Runaround" (1942) byIsaac Asimov.
The term was coined and first used by the
Russian-born American scientist and
writer Isaac Asimov.
Asimov also proposed his three "Laws
of Robotics",

ASIMOV’S LAW
Law One:
A robot may not injure a human being, or, through
inaction, allow a human being to come to harm,
unless this would violate a higher order law.
 Law Two:
A robot must obey orders given it by human beings,
except where such orders would conflict with a
higher order law.
 Law Three:
A robot must protect its own existence as long as such
protection does not conflict with a higher order law.

GENERATION OF ROBOT
First generation robotsweredesigned to performfactory work.
Such robots performed simple tasks that were dangerous or
unpleasant for people.
Robots were used to weld, spray paint, move heavy objects,
handle hot materials, etc.
Second generation Robots perform more complex tasks and
simulate many human functions.
Such robots move, sense surroundings, and respond to changes in
their environment.

Class1: Manual Handling Device
Class2:Fixed-SequenceRobot
Class3:VariableSequenceRobot
Class4:PlaybackRobot
Class5:NumericalControl Robot
Class6:Intelligent Robot
TYPES OF ROBOTICS
ACCORDING TO JIRA :
(JAPANESE INDUSTRIAL ROBOT ASSOCIATION)

ROBOT ANATOMY
Manipulator consists of joints and links
Joints provide relative motion
Links are rigid members between joints
Various joint types: linear and rotary
Each joint provides a “degree-of-freedom”
Most robots possess five or six degrees-of-
freedom
Robot manipulator consists of two
sections:
Body-and-arm – for positioning of objects in
the robot's work volume
Wrist assembly – for orientation of objectsS A M P A T H . K A P / E E E - D A C E 11

ROBOT ANATOMY
Base
Link0
Joint1
Link2
Link3
Joint3 End of Arm
Link1
Joint2

MANIPULATOR JOINTS
Translational motion
Linear joint (type L)
Orthogonal joint (type O)
Rotary motion
Rotational joint (type R)
Twisting joint (type T)
Revolving joint (type V)S A M P A T H . K A P / E E E - D A C E 13

1. Linear joint (L). The relative movement between the
input link and the output link is a linear sliding motion,
with the axes of the two links being parallel.
2. Orthogonal joint (O). This is also a linear sliding motion,
but the input and output links are perpendicular to each
other during the move.
3. Rotational joint (R). This type provides a rotational
relative motion of the joints, with the axis of rotation
perpendicular to the axes of the input and output links.
4. Twisting joint (T). This joint also involves a rotary motion,
but the axis of rotation is parallel to the axes of the two
links.
5. Revolving joint (V). IN this joint type, the axis of the input
link is parallel to the axis of rotation of the joint, and the
axis of the output link is perpendicular to the axis of

LINEAR MOTION(L)

ORTHOGONAL(O)

ROTATIONAL (R)

TWISTING (T)

REVOLVING (V)

JOINT NOTATION SCHEME
Uses the joint symbols (L, O, R, T, V) to designate
joint types used to construct robot manipulator
Separates body-and-arm assembly from wrist
assembly using a colon (:)
Example: TLR : TR
Common body-and-arm configurations …

COMMON ROBOT CONFIGURATIONS
Robot manipulatorconsists of two sections;
1) Body-and-arm:for positioning of objects in the robot's work volume
• Polar configuration
• Cylindrical configuration.
• Cartesiancoordinate robot.
• Jointed arm robot.
• SCARA
2) Wrist assembly: for orientationof objects.
• Roll
• Pitch
• Yaw

POLAR COORDINATE
BODY-AND-ARM ASSEMBLY
Notation TRL:
Consists of a sliding arm (L joint) actuated
relative to the body, which can rotate about
both a vertical axis (T joint) and horizontal
axis (R joint) S A M P A T H . K A P / E E E - D A C E 22

CYLINDRICAL BODY-AND-ARM ASSEMBLY
Notation TLO:
Consists of a vertical
column, relative to which
an arm assembly is
moved up or down
The arm can be moved in or
out relative to the column

CARTESIAN COORDINATE
BODY-AND-ARM ASSEM
Notation LOO:
Consists of three sliding
joints, two of which are
orthogonal
Other names include
rectilinear robot and x-
y-z robot

JOINTED-ARM ROBOT
Notation TRR:

SCARA ROBOT
Notation VRO
SCARA stands for
Selectively Compliant
Assembly Robot Arm
Similar to jointed-arm
robot except that
vertical axes are used
for shoulder and elbow
joints to be compliant in
horizontal direction for
vertical insertion tasks

To establish the orientation of the object, we
can define 3 degrees of freedom for the
robot's wrist. The following is one possible
configuration for a 3 d.o.f. wrist assembly:
•Roll. This d.o.f. can be accomplished by a T-
type joint to rotate the object about the arm axis.
•Pitch. This involves the up-and-down rotation of
the object, typically done by means of a type R
joint.
•Yaw. This involves right-to-left rotation of the
object, also accomplished typically using an R-
type joint.
These definitions are illustrated in the followingS A M P A T H . K A P / E E E - D A C E 27

EXAMPLE
Sketch following manipulator configurations
(a) TRT:R, (b) TVR:TR, (c) RR:T.
Solution:
T
R
T
V
(a) TRT:R
R
T
R
T R
TR
R
(c) RR:T(b) TVR:TR S A M P A T H . K A P / E E E - D A C E 28

ROBOT CONTROL SYSTEMS
Limited sequence control – pick-and-place
operations using mechanical stops to set
positions
Playback with point-to-point control – records
work cycle as a sequence of points, then
plays back the sequence during program
execution
Playback with continuous path control –
greater memory capacity and/or
interpolation capability to execute paths (in
addition to points)
Intelligent control – exhibits behavior that
makes it seem intelligent, e.g., responds to
sensor inputs, makes decisions,
communicates with humans

Point-to-Point (PTP)
The PTP robot is capable of moving from one
point to another point. The locations are
recorded in the control memory. PTP
robots do not control the path to get from
one point to the next point. The
programmer exercises some control over
the desired path to be followed by
programming a series of points along the
path. Common applications include
component insertion, spot welding, hole
drilling, machine loading and unloading,
and crude assembly operations.

CONTROLLED-PATH ROBOT
In controlled path robots, the control
equipment can generate paths of different
geometry such as straight lines, circles, and
interpolated curves with a high degree of
accuracy. Good accuracy can be obtained
at any point along the specified path. Only
the start and finish points and the path
definition function must be stored in the
robot's control memory. It is important to
mention that all controlled-path robots have
a servo capability to correct their path.S A M P A T H . K A P / E E E - D A C E 31

CONTINUOUS-PATH (CP)
The CP robot is capable of performing movements
along the controlled path. With CP control, the
robot can stop at any specified point along the
controlled path. All the points along the path must
be stored explicitly in the robot's control memory.
Straight-line motion is the simplest example for this
type of robot. Some continuous- path controlled
robots also have the capability to follow a smooth
curve path that has been defined by the
programmer. In such cases the programmer
manually moves the robot arm through the desired
path and the controller unit stores a large number
of individual point locations along the path in
memory. Typical applications include spray
painting, finishing gluing, and arc weldingS A M P A T H . K A P / E E E - D A C E 32

END EFFECTORS
The special tooling for a
robot that enables it to
perform a specific task
Two types:
Grippers – to grasp and
manipulate objects (e.g.,
parts) during work cycle
Tools – to perform a process,
e.g., spot welding, spray
painting

GRIPPERS AND TOOLS

Degree of Freedom (DOF)
• Six degree of freedom is needed to fully place the object
in space and also oriented it as desired (move & rotate
along x-, y- and z-axes)
• If fewer than six, the robot’s capabilities are limited
• E.g.
• Robot with three DOF can only move along x-, y-
and z-axes. No orientation can be specified (only
parallel to axes)
• Robot with five DOF capable of rotating about three
axes but only moving along x-, y-axes (not z-axes)

Degree of Freedom (DOF) (cont)
• A system with seven degrees of freedom does not have
unique solution. There are infinite number of ways it can
position a part and orientate it at desired location. There
must be additional decision making routine (for the
controller) that allows it to pick the fastest or shortest
path to the desired destination.
• Due to this which take much computing power and time
no seven DOF is used in industry
• Human arms have seven DOF. (Shoulder – 3 DOF,
Elbow – 1 DOF, wrist - 3 DOF)
• In robot end effectors never consider as on of DOF
• ½ DOF - if movement is not fully controlled (e.g only
can fully extended or retracted, can only at 0, 30, 60 or
90 degrees) S A M P A T H . K A P / E E E - D A C E 36

Degrees Of Freedom
The Three Degrees Of Freedom Located In The
Arm Of A Robotic System Are:
The Rotational Reverse: Is The
Movement of the Arm Assembly about a Rotary
Axis, Such As Left-And-Right Swivel of the
Robot’s Arm about a Base.
The Radial Traverse: Is The Extension
And Retraction Of The Arm Or The In-And-Out
Motion Relative To The Base.
The Vertical Traverse: Provides The Up-
And-Down Motion Of The Arm Of The Robotic
System. S A M P A T H . K A P / E E E - D A C E 37

WRIST CONFIGURATIONS
Wrist assembly is attached to end-of-arm
End effector is attached to wrist
assembly
Function of wrist assembly is to orient
end effector
Body-and-arm determines global position of
end effector
Two or three degrees of freedom:
Roll
Pitch
Yaw

What are the parts of a
robot?
•Manipulator
•Pedestal
•Controller
•End Effectors
•Power Source S A M P A T H . K A P / E E E - D A C E 41

Manipulator
(Mimics the human arm)
• Base
• Appendage
Shoulder
Arm
Grippers

MANIPULATOR
It consists of base, arm and wrist similar
to a human arm. It also includes power
source either electric, hydraulic or
pneumatic on receiving signals from
robot this mechanical unit will be
activated. The movement of manipulator
can be in relation to its coordinates
system which may be Cartesian,
cylindrical etc. depending on the
controller, the movements may be point
to point motion or continuous motion.

Pedestal(BAS
E)
•Supports the
manipulator.
•Acts as a
counterbalance.

Controller
(The brain)
• Issues instructions
to the robot.
• Controls peripheral
devices.
• Interfaces with
robot.
• Interfaces with
humans.S A M P A T H . K A P / E E E - D A C E 46

The instructions (programme) to
the robot to perform the desired
tasks are input through the key
board of this unit. A teach
pendant is also provided for
giving non-textual commands
input. The controller converts
the input program to suitable
signals which activate the
manipulator to perform theS A M P A T H . K A P / E E E - D A C E 47

End
Effectors(The hand)
• Spray paint
attachments
• Welding
attachments
• Vacuum heads
• Hands
• GrippersS A M P A T H . K A P / E E E - D A C E 48

The end effector is the special-purpose
tooling which enables the robot to
perform a particular job. In the
terminology of robotics, an end effector
can be defined as a device which is
attached to the robot’s wrist to perform a
specific task. The task may be work part
handling, spot welding, spray painting, or
any of a great variety of other functions.
For purpose of organization, we
will divide the various types of end
effectors into two categories: grippers
and tools.

Power
Source
(The food)
• Electric
• Pneumatic
• Hydraulic

THE THREE POWER SOURCES USED IN
CURRENT ROBOTS ARE:
All Robots Use Electricity as the Primary Source
of Energy.
Electricity Turns The Pumps That Provide
Hydraulic And Pneumatic Pressure.
It Also Powers The Robot Controller And All The
Electronic Components And Peripheral Devices.
In All Electric Robots, The Drive Actuators, As Well
As The Controller, Are Electrically Powered.
Because Electric Robot Do Not Require A
Hydraulic Power Unit, They Conserve Floor Space
And Decrease Factory Noise.
No Energy Conversion Is Required.S A M P A T H . K A P / E E E - D A C E 51

These Are Generally Found In
Relatively Low-Cost Manipulators with
Low Load Carrying Capacity.
 Pneumatic Drives Have Been Used
For Many Years For Powering Simple
Stop-To-Stop Motions.
It Is Inherently Light Weight,
Particularly When Operating
Pressures Are Moderate.

 Are either Linear Position Actuators or a
Rotary Vane Configuration.
 Hydraulic Actuators Provide A Large Amount
Of Power For A Given Actuator.
The High Power-To-Weight Ratio Makes The
Hydraulic Actuator An Attractive Choice For
Moving Moderate To High Loads At
Reasonable Speeds And Moderate Noise
Level.
 Hydraulic Motors Usually Provide A More
Efficient Way Of Energy To Achieve A Better
Performance, But They Are Expensive And
Generally Less Accurate.

ROBOT SPECIFICATION:
How close does the
robot get to the desired point? When the
robot's program instruct the robot to
move to a specified point, it does not
actually perform as per specified. The
accuracy measures such variance. That
is, the distance between the specified
position that a robot is trying to achieve
(programming point), and the actual X, Y
and Z resultant position of the robot end
effector.

The ability of a robot
to return repeatedly to a given
position. It is the ability of a robotic
system or mechanism to repeat the
same motion or achieve the same
position. Repeatability is a measure of
the error or variability when repeatedly
reaching for a single position.
Repeatability is often smaller than
accuracy.

Each
joint or axis on the robot introduces
a degree of freedom. Each DOF can
be a slider, rotary, or other type of
actuator. The number of DOF that a
manipulator possesses thus is the
number of independent ways in
which a robot arm can move.
Industrial robots typically have 5 or 6
degrees of freedom.

The smallest
increment of motion or distance
that can be detected or controlled
by the robotic control system. It is
a function of encoder pulses per
revolution and drive (e.g.
reduction gear) ratio. And it is
dependent on the distance
between the tool center point and
the joint axis. S A M P A T H . K A P / E E E - D A C E 57

A three-dimensional
shape that defines the boundaries
that the robot manipulator can
reach; also known as reach
envelope.
The maximum horizontal
distance from the center of the
robot base to the end of its wrist.

A robot moving at full
extension with all joints moving simultaneously
in complimentary directions at full speed. The
maximum speed is the theoretical values which
does not consider under loading condition...
The maximum payload is the
amount of weight carried by the robot
manipulator at reduced speed while maintaining
rated precision. Nominal payload is measured
at maximum speed while maintaining rated
precision. These ratings are highly dependent
on the size and shape of the payload due to
variation in inertia.

Work Volume/Workspace - The
robot tends to have a fixed and limited
geometry. The work envelope is the
boundary of positions in space that the
robot can reach. For a Cartesian robot
(like an overhead crane) the workspace
might be a square, for more sophisticated
robots the workspace might be a shape
that looks like a ‘clump of intersecting
bubbles’.

There are numerous vendors of robots throughout the
world, most now in Japan. Some of the primary vendors
are:
Fanuc (Japan)
Kuka (Germany)
ABB (Sweden, US)
Adept (US)
Seiko (Japan)
Motoman (Japan)S A M P A T H . K A P / E E E - D A C E 63

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