Robotics Good Slide

7/30/2019 Robotics Good Slide

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BEE4393 (Automation

and Robotics)

Cik Mahfuzah Mustafaroom 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?

o The term robot was first introduced by a Czech

dramatist, Karel Capek in his 1921 play

"Rossum's Universal Robots". He was referringto a perfect and tireless worker performing

manual labour jobs for human beings.

o Isaac Asimov, coined the word robotics as the

science of the study of robots, in his sciencefiction 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 withouthuman intervention.


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Automation is generally regarded as being

able to be divided into 2 types:

1. Fixed automation

2. 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 athigh rates and low cost

Eg: automobile industry, where highly integrated

transfer line are used to perform machine

operation on engine and transmissioncomponents


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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

Date Development

mid- 1 700s J. de Vaucanson built several human-sized

mechanical dolls that played music.

1971 The -Stanford Arm," a small electrically powered robot

arm, developed at Stanford University.

1979 Development of S.CARA type robot (Selective

Compliance Arm for Robotic Assembly) at Yamanashi

University in Japan for assembly. Several commercial

SCARA robots introduced around 1981


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Social and Economic Issues

In the social area, what are the main issues related to robotics? Howwill the labour and manpower market be affected by robotics? Howmany 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 affectproductivity and international economic competition?

What kind of retraining and education is needed to upgrade thepresent work force?

Will foreign investors still choose Malaysia (as cheap labour will notbe needed when factories are run by robots)?

Some 90 percent of Malaysian industry is in the SMI (Small andMedium Industry) category. Can SMIs afford installation of roboticsin the near future? Or will robotics benefit only MNCs (MultinationalCorporations)?


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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 issimilar to a joint in thehuman body

Each joint gives therobot with a degree-of-freedom(d.o.f)ofmotion

In the nearly allcases, only 1 d.o.f isallowed to a joint

Joint


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What is a robot link?

Links are rigid

components that form

a chain connectedtogether by joints

Each joint has two

links, known as an

input link and anoutput link

Link


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Types of robot joints

1. Linear joint

2. Orthogonal joint

3. Rotational joint

4. Twisting joint

5.

Revolving joint


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Linear joint

The relative movement

between the input link

and the output link is alinear 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 linksare perpendicular to

each other during the

move


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Rotational joint

This type provides a

rotational relative

motion of the joints, withthe axis of rotation

perpendicular to the

axes of the input andoutput links


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Twisting joint

This joint also involves

a rotary motion, but the

axis of rotation isparallel 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 ofthe joint, and the axis of

the output link is

perpendicular to theaxis of rotation


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This joint-link numbering, scheme

is shown below.


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GENERAL CLASIFICATION OF

ROBOTSo Low technology

o Medium technology

o 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 StructureNormally, robot manipulators are classified

according to their arm geometry or kinematic

structure. The majority of these manipulators fall

into one of these five configuration:

1. Cartesian Type Configuration (PPP)

2. Cylindrical Type Configuration (RPP)3. Spherical Type Configuration (RRP)

4. SCARA Type Configuration (RRP or PRR)

5. 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 assemblyapplications 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 arotation 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 manipulatorsare 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 firsttwo joints are revolute with the third joint as prismatic, or the first joint isrevolute 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 anthromorphicmanipulator. These type of robot resembles human arm. Twocommon revolute designs are the elbow type manipulator such asthe PUMA and the parallelogram linkage such as the CincinnatiMilacron 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:

1. Stepper motors2. DC servomotors

3. AC servomotors

4. Hydraulic pistons5. Pneumatic pistons


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Electric Drive

Small and medium size robots are usuallypowered by electric drives via gear trains usingservomotors 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 hydraulicdrives.

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 atCarnegle-Mellon University, USA. Is used electricmotors located at the manipulator joints without the

usual mechanical transmission linkages used on mostrobots.

The drive motor is located contiguous to the joint.

Benefits: Eliminate backlash and mechanical defiencies

Eliminate the need of a power transmission (thus moreefficient)

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 closedto 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

gripperThis special hand, with

pair of pneumatic

actuators, is one of themany special hand

designs for industrial

robots. It is suitable forparts of light weight.


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Special hand for glass tubes

This hand is specially

designed for industrial

robots to securelygrasping of relatively

short tubes.


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Simple vacuum cup hand

This simple vacuum cup

hand is suitable for

Handling fragile partssuch 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 varioustasks.


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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 thepot 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 beforeplating. 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-changingoperation 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
http://world.honda.com/HDTV/ASIMO/http://world.honda.com/HDTV/ASIMO/

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Robotics Good Slide