Robot Technology
Chapter 10
Robotics by Muhammad Moeen Sultan
Robot Introduction
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General purpose (perform a variety of
functions independently)
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Programmable (Sequence, repetition,
decision making
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Anthropomorphic characteristics
Perform specific functions like machine
loading, spot welding, spray painting,
assembly, etc.
Robotics by Muhammad Moeen Sultan
Definition of Robot
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A robot is a programmable, multifunction
manipulator designed to move material,
parts, tools, or special devices through
variable programmed motions for the
performance of a variety of tasks.
Robotics by Muhammad Moeen Sultan
Laws of Robotics
• Law 1: A robot may not injure a human being
• Law 2: A robot must obey orders given to it by
human beings, except where such orders would
conflict with a higher order law
• Law 3: A robot must protect its own existence as
long as such protection does not conflict with a
higher order law
Robotics by Muhammad Moeen Sultan
Robot Physical Configurations
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Industrial Robots come in a variety of shapes and
sizes
On this base they are distinguished
 Polar coordinate configuration
 Cylindrical coordinate configuration
 Joined arm configuration
 Cartesian coordinate configuration
Robotics by Muhammad Moeen Sultan
Polar coordinate configuration
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Spherical coordinates (Partial sphere)
• Rotary base
• Pivot used to raise and lower an arm
• In-out movement
Robotics by Muhammad Moeen Sultan
Cylindrical coordinate configuration
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Swivels about a vertical axis
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Up-down movement
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In-out movement
Robotics by Muhammad Moeen Sultan
Jointed Arm configuration
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Similar in appearance to
human arm
Rotated base, shoulder
joint, elbow joint, wrist
joint.
Robotics by Muhammad Moeen Sultan
Cartesian coordinate configuration
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Three orthogonal slides
Slides are parallel to the
x,y,z axis.
Robotics by Muhammad Moeen Sultan
Purpose of a Robot
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Purpose of a robot is to perform
useful task
End-effector
The tool, gripper, or other device mounted at the end of
a manipulator, for accomplishing useful tasks

Hand
Robotics by Muhammad Moeen Sultan
Degrees-of-Freedom (DOF):
The number of independent motions
a device can make. (Also called
mobility)
five degrees of
freedom
Robotics by Muhammad Moeen Sultan
Degree of Freedom
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Six basic motions for a robot to
move in a required sequence of
motions
Not all robots are equipped with it
Three arm and body movement and
three wrist movements.
Robotics by Muhammad Moeen Sultan
Six Degree of Freedom
Robotics by Muhammad Moeen Sultan
Motion Systems

Point-to-point (PTP)
Moves from one point location to
another. Can adopt any path.
Examples:
loading unloading, pick and place,
spot welding
Robotics by Muhammad Moeen Sultan
Motion Systems

Contouring (Continuous Path)
Move on a Smooth compound curve
Complete path is remembered
Examples:
Paint spray, continuous welding.
Robotics by Muhammad Moeen Sultan
Other technical features
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Determine its efficiency, effectiveness
Some of the technical features are
•
•
•
•
•
Work volume
Precision of movement
Speed of movement
Weight carrying capacity
Types of drive system
Robotics by Muhammad Moeen Sultan
Technical features

Work volume
• Space within which a robot can operate.
• Determined by its configuration, size
and the limits of its arms.
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Polar coordinates
Cylindrical coordinates
Cartesian
Jointed arm
–
–
-
Robotics by Muhammad Moeen Sultan
partial sphere
cylindrical
rectangular
irregular
Technical features

Precision of movement
The precision with which the robot can
move the end of its wrist.
1.
2.
3.
Spatial resolution
Accuracy
Repeatability
Robotics by Muhammad Moeen Sultan
Technical features

Spatial resolution
• Smallest increment of motion
• Depends on the control system and
feedback
Control resolution=
range
control increments
Robotics by Muhammad Moeen Sultan
Technical features

Accuracy
• The ability of a robot to go to the specified
position without making a mistake.
• Closely related to spatial resolution
Robotics by Muhammad Moeen Sultan
Technical features

Repeatability
• Ability to position a wrist back to the
previously visited point.
Robotics by Muhammad Moeen Sultan
Technical features

Speed of movement
• The amount of distance per unit time at
which the robot can move.
• Speed of the end effectors
• Determined by the weight of the object
Weight carrying capacity
• Lifting over 1000 lb
Robotics by Muhammad Moeen Sultan
Types of Drive system

Hydraulic (mechanical, high strength)

Electric motor (stepper, servo, less
strength, better accuracy and repeatability

Pneumatic (quick, less strength)
Robotics by Muhammad Moeen Sultan
End effectors

Grippers
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Tools
Robotics by Muhammad Moeen Sultan
Grippers
Robotics by Muhammad Moeen Sultan
Tools as end effectors
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Spot welding
Spray painting
Drilling
Grinders
Heating torches
Robotics by Muhammad Moeen Sultan
Robotic sensors
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Vision
Tactile and proximity
voice
Robotics by Muhammad Moeen Sultan
Programming The Robot
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Programming Methods
• Manual Method
• Walkthrough Method
• Lead through Method
• Off-line Programming
Robotics by Muhammad Moeen Sultan
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Manual Method
Mechanical stops, cams, switches or
relays
Uses: short work cycle like pick and place
operation
video
Robotics by Muhammad Moeen Sultan

Walkthrough Method
• Manually moves the robot arm
• Each movement is recorded
• No worry about the cycle time
• Getting the position and sequence
correct
Uses: spray painting, arc welding
Robotics by Muhammad Moeen Sultan
video
Robotics by Muhammad Moeen Sultan

Lead through Method
• Use of small hand held devices
• Switches, dials
• Each motion is recorded in memory
Robotics by Muhammad Moeen Sultan
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Off-line programming
• Similar to NC
• Computer terminal
• No loss of production time (no teaching)
• Can be programmed when still in
production
Robotics by Muhammad Moeen Sultan
Robotics by Muhammad Moeen Sultan
Work Cell Control

Work with other things
• Processing equipments, work parts, conveyors,
tools and human operators
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Coordinating all the activities within the
robot workstation
Sequencing and simultaneous activities
Work cell controller
Robotics by Muhammad Moeen Sultan
Work Cell Control
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Example
• Robotic arm
• Machine tool
• Two conveyors
Robotics by Muhammad Moeen Sultan
Robotics by Muhammad Moeen Sultan
Work Cell Control
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Operate Sequentially
Certain steps are completed before
next operation
• Picking, proper location of the piece
• Start, by Loading the work piece
• Machining complete
Robotics by Muhammad Moeen Sultan
Interlocks

Sequence continues until a certain
condition or set of conditions has
been satisfied

Incoming
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Outgoing
Robotics by Muhammad Moeen Sultan
Interlocks
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Limit switches
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Pressure switches
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Photoelectric devices
Robotics by Muhammad Moeen Sultan
Robotics by Muhammad Moeen Sultan
Robotics by Muhammad Moeen Sultan