BEE4393 Automation and Robotics

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BEE4393 (Automation and Robotics)

• Cik Mahfuzah Mustafa
• room no A1-02-07
• ext 2323

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Contents

• History of Robotics
• Robotics Application
• Social and Economic Issues
• Robot anatomy and Work Volume
• Robot Configuration and work Space
• End-effectors Grippers and Tools
• Robot Actuators and Drive Systems
• Safety Consideration

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Who introduced the word robot?

• The term robot was first introduced by a Czech
  dramatist, Karel Capek in his 1921 play "Rossum's
  Universal Robots". He was referring to a perfect
  and tireless worker performing manual labour jobs
  for human beings.
• Isaac Asimov, coined the word robotics as the
  science of the study of robots, in his science
  fiction stories about robots in 1940s.

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Definition

• Robot term from Websters dictionary- An
  automatic device that performs function
  ordinarily ascribed to human being
• 'Automation' refers to a mode of operation in
  which any machine or piece of equipment is
  capable of working without human intervention.

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Automation is generally regarded as being able to
be divided into 2 types

• Fixed automation
• Flexible automation

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Fixed automation

• Used when the volume of production is very high
  and it is, therefore, appropriate to design
  specialized equipment to process products at
  high rates and low cost
• Eg automobile industry, where highly integrated
  transfer line are used to perform machine
  operation on engine and transmission components

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Flexible automation

• Most suitable for the mid-volume production
  range. Typically consists of a series of
  workstation that are interconnected by
  material-handling and storage equipment to
  process different product configuration at the
  same time to control manufacturing system
• Eg Flexible Manufacturing System (FMS), Computer
  Integrated Manufacturing (CIM)

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History of Robotics
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Social and Economic Issues

• In the social area, what are the main issues
  related to robotics? How will the labour and
  manpower market be affected by robotics? How many
  workers are likely to be displaced?
• What are the impacts on the professional and
  semiprofessional work force who are employed in
  manufacturing? Also, will robotics affect
  productivity and international economic
  competition?
• What kind of retraining and education is needed
  to upgrade the present work force?
• Will foreign investors still choose Malaysia (as
  cheap labour will not be needed when factories
  are run by robots)?
• Some 90 percent of Malaysian industry is in the
  SMI (Small and Medium Industry) category. Can
  SMIs afford installation of robotics in the near
  future? Or will robotics benefit only MNCs
  (Multinational Corporations)?

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Robot anatomy and Work Volume

• Robot anatomy deals with
• the types and sizes of these joints and links
• and other aspects of the manipulators physical
  construction

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What is a joint?

• A joint of robot is similar to a joint in the
  human body
• Each joint gives the robot with a
  degree-of-freedom(d.o.f)of motion
• In the nearly all cases, only 1 d.o.f is allowed
  to a joint

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What is a robot link?

• Links are rigid components that form a chain
  connected together by joints
• Each joint has two links, known as an input link
  and an output link

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Types of robot joints

• Linear joint
• Orthogonal joint
• Rotational joint
• Twisting joint
• Revolving joint

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Linear joint

• 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

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Orthogonal joint

• This is also linear
• sliding motion, but the
• input and output links
• are perpendicular to
• each other during the
• move

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Rotational joint

• 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

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Twisting joint

• This joint also involves
• a rotary motion, but the
• axis of rotation is
• parallel to the axes of
• the two links

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Revolving joint

• In this types, 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 rotation

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This joint-link numbering, scheme is shown below.
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GENERAL CLASIFICATION OF ROBOTS

• Low technology
• Medium technology
• High technology

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Low technology

• Material handling, using simple assembly
• 2 to 4 axes of movement
• Stop at extreme

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Medium technology

• Pick-and-place
• Material handling
• 4 to 6 axes

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High technology

• Material handling
• Pick-and-place
• Loading and unloading
• Painting and welding
• 6 to 9 axes

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Robot Classification Based On Kinematic Structure

• Normally, robot manipulators are classified
• according to their arm geometry or kinematic
• structure. The majority of these manipulators
  fall
• into one of these five configuration
• Cartesian Type Configuration (PPP)
• Cylindrical Type Configuration (RPP)
• Spherical Type Configuration (RRP)
• SCARA Type Configuration (RRP or PRR)
• Revolute Type Configuration (RRR)

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Cartesian Type Configuration (PPP)
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Cartesian Type Configuration (PPP)

• Manipulator whose first three joints are
  prismatic are known as a Cartesian manipulator..
  Cartesian manipulator are useful for table-top
  assembly applications and, as gantry robots for
  transfer of material and cargo
• Advantages
• - 3 linear axes
• - Easy to visualize
• - Rigid structure
• - Easy to program off-line
• - Linear axes make for easy mechanical
  stops
• Disadvantage
• - Can only reach in front of itself
• - Requires large floor space for size of
  work envelop
• - Axes hard to seal

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Cylindrical Type Configuration (RPP)
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Cylindrical Type Configuration (RPP)

• For cylindrical type manipulator, its first joint
  is revolute which produces a rotation about the
  based, while its second and third joints are
  prismatic.
• Advantages
• - 2 linear axes, 1 rotating axis
• - Can reach all around itself
• - Reach and height axes rigid
• - Rotational axis easy to seal.
• Disadvantages
• - Cannot reach above itself
• - Base rotation axis is less rigid than a
  linear axis
• - Linear axes hard to seal
• - Will not reach around obstacles
• - Horizontal motion is circular

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Spherical Type Configuration (RRP)
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Spherical Type Configuration (RRP)

• The first two joints of this type of manipulators
  are revolute, while its third Joint is prismatic.
• Advantages
• - 1 linear axis, 2 rotating axes
• - Long horizontal reach
• Disadvantages
• - Cannot reach around obstacles
• - Generally has short vertical reach

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SCARA Type Configuration (RRP or PRR)
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SCARA Type Configuration (RRP or PRR)

• The word SCARA stands for Selective Compliant
  Articulated Robot for Assembly. There are two
  type of SCARA robot configuration either the
  first two joints are revolute with the third
  joint as prismatic, or the first joint is
  revolute with the second and third Joints as
  prismatic.
• Advantages
• - 1 linear axis, 2 rotating axes
• - Height axis is rigid
• - Large work area floor space
• - Can reach around obstacles
• - Two ways to reach a point
• Disadvantages
• - Difficult to program off-line
• - Highly complex arm

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Revolute Type Configuration (RRR)
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Revolute Type Configuration (RRR)

• Revolute manipulator is also called articulated
  or anthromorphic manipulator. These type of robot
  resembles human arm. Two common revolute designs
  are the elbow type manipulator such as the PUMA
  and the parallelogram linkage such as the
  Cincinnati Milacron T3 735.
• Advantages
• - 3 rotating, axes
• - Can reach above or below obstacles
• - Largest work area for least work space
• - Two or four ways to reach a point
• Disadvantages
• - Difficult to program off-line
• - The most complex manipulator

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Robot Actuators and Drive Systems

• What is actuator?
• The commonly used actuators are
• Stepper motors
• DC servomotors
• AC servomotors
• Hydraulic pistons
• Pneumatic pistons

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Electric Drive

• Small and medium size robots are usually powered
  by electric drives via gear trains using
  servomotors and stepper motors.
• Advantages
• - Better accuracy repeatability
• - Require less floor space
• - More towards precise work such as assembly
  applications
• Disadvantages
• - Generally not as speedy and powerful as
  hydraulic robots
• - Expensive for large and powerful robots,
  can become fire hazard

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Hydraulic Drive

• Larger robots make use of hydraulic drives.
• Advantages
• - more strength-to-weight ratio
• - can also actuate at a higher speed
• Disadvantages
• - Requires more floor space
• - Tendency to oil leakage.

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Pneumatic Drive

• For smaller robots that possess fewer degrees of
  freedom (two- to fourjoint motions).
• They are limited to pick-and-place tasks with
  fast cycles.

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Direct Drive Robots

• In 1981 a "direct- drive robot" was developed at
  Carnegle-Mellon University, USA. Is used electric
  motors located at the manipulator joints without
  the usual mechanical transmission linkages used
  on most robots.
• The drive motor is located contiguous to the
  joint.
• Benefits
• Eliminate backlash and mechanical defiencies
• Eliminate the need of a power transmission (thus
  more efficient)
• Joint backdrivable (allowing for joint-space
  force sensing)

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End-effectors Grippers and Tools

• What is gripper? What is tool?
• Mechanical grippers
• Vacuum systems
• Magnetic Pickups
• Tools

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Cam-operated hand

• It can easily handle heavy weights
• or bulky objects. It is designed to
• hold the object so that its center
• of gravity (CG) is kept very closed
• to the wrist of hand. The short
• distance between the wrist and
• the CG minimizes the twisting
• tendency of a heavy or bulky
• object.

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Special hand with modular gripper

• This special hand, with
• pair of pneumatic
• actuators, is one of the
• many special hand
• designs for industrial
• robots. It is suitable for
• parts of light weight.

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Special hand for glass tubes

• This hand is specially
• designed for industrial
• robots to securely
• grasping of relatively
• short tubes.

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Simple vacuum cup hand

• This simple vacuum cup
• hand is suitable for
• Handling fragile parts
• such as cathode ray
• tube face plates
• (Illustrated).

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Magnetic Pick up

• Magnetic handling is
• most suitable for parts
• of ferrous contents.
• Magnets can be
• scientifically designed and
• made in numerous shapes
• and sizes to perform various
• tasks.

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Ladle

• Ladling hot materials such as
• molten metal is a hot and
• hazardous job for which
• industrial robots are well suited.
• In piston casting permanent mold
• die casting and related
• applications, the robot can be
• programmed to scoop up and
• transfer the molten metal from the
• pot to the mold, and then do the
• pouring.

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Spray gun

• Ability of the industrial robot to do
• multipass spraying with controlled
• velocity fits it for automated
• application of primers, paints, and
• ceramic or glass frits, as well as
• application of masking agents used before
• plating. For short or medium-length
• production runs, the industrial robot would
• often be a better choice than a special
• purpose setup requiring a lengthy
• change-over procedure for each different
• part. Also the robot can spray parts with
• compound curvatures and multiple
• surfaces.

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Tool changing

• A single industrial robot can
• also handle several tools
• sequentially, with an
• automatic tool-changing
• operation programmed into
• the robot's memory. The
• tools can be of different
• types or sizes, permitting
• multiple operations an the
• same workpiece

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Safety Consideration

• When?
• Practice it as soon as starting robotics project
• Must be built into robotics system at the outset
• Do not risk injuries by robots

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What Dangers?

• Repairing a robot
• Training/programming robot
• Normal operation
• Power supply

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What sort of injuries?

• Bodily impact
• Pinching-caught in grippers or joints
• Pining human against a structure

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• http//world.honda.com/HDTV/ASIMO/
• for Asimo video