BEE4393 (Automation and Robotics)

Cik Mahfuzah Mustafa

room no :A1-02-07

ext: 2323

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

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 referring to 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 science fiction stories about robots in 1940s.

Definition

Robot term from Webster’s 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.

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

1. Fixed automation

2. Flexible automation

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

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)

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

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)?

Robot anatomy and Work Volume

Robot anatomy deals with: the types and sizes of these joints and

links and other aspects of the manipulator’s

physical construction

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

Joint

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

Link

Types of robot joints

1. Linear joint

2. Orthogonal joint

3. Rotational joint

4. Twisting joint

5. Revolving joint

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

Orthogonal joint

This is also linear

sliding motion, but the

input and output links

are perpendicular to

each other during the

move

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

Twisting joint

This joint also involves

a rotary motion, but the

axis of rotation is

parallel to the axes of

the two links

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

This joint‑link numbering, scheme is shown below.

GENERAL CLASIFICATION OF ROBOTSo Low technologyo Medium technologyo High technology

Low technology

Material handling, using simple assembly2 to 4 axes of movementStop at extreme

Medium technology

Pick-and-place Material handling 4 to 6 axes

High technology

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

Robot Classification Based On Kinematic StructureNormally, robot manipulators are classifiedaccording to their arm geometry or kinematicstructure. The majority of these manipulators fallinto 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)

Cartesian Type Configuration (PPP)

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

Cylindrical Type Configuration (RPP)

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

Spherical Type Configuration (RRP)

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

SCARA Type Configuration (RRP or PRR)

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

Revolute Type Configuration (RRR)

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

Robot Actuators and Drive Systems

What is actuator?The commonly used actuators are:1. Stepper motors2. DC servomotors3. AC servomotors4. Hydraulic pistons5. Pneumatic pistons

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

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.

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.

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)

End-effectors: Grippers and Tools

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

Cam‑operated hand

It can easily handle heavy weights

or bulky objects. It is designed tohold the object so that its center of gravity (CG) is kept very closedto the wrist of hand. The shortdistance between the wrist andthe CG minimizes the twistingtendency of a heavy or bulkyobject.

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.

Special hand for glass tubes

This hand is specially

designed for industrial

robots to securely

grasping of relatively

short tubes.

Simple vacuum cup hand

This simple vacuum cup

hand is suitable for

Handling fragile parts

such as cathode ray

tube face plates

(Illustrated).

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.

Ladle

Ladling hot materials such asmolten metal is a hot andhazardous job for whichindustrial robots are well suited.In piston casting permanent molddie casting and relatedapplications, the robot can beprogrammed to scoop up andtransfer the molten metal from thepot to the mold, and then do thepouring.

Spray gun

Ability of the industrial robot to domultipass spraying with controlledvelocity fits it for automatedapplication of primers, paints, andceramic or glass frits, as well asapplication of masking agents used beforeplating. For short or medium‑lengthproduction runs, the industrial robot wouldoften be a better choice than a specialpurpose setup requiring a lengthychange‑over procedure for each differentpart. Also the robot can spray parts withcompound curvatures and multiplesurfaces.

Tool changing

A single industrial robot canalso handle several toolssequentially, with anautomatic tool‑changingoperation programmed intothe robot's memory. Thetools can be of differenttypes or sizes, permittingmultiple operations an thesame workpiece

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

What Dangers?

Repairing a robot Training/programming robot Normal operation Power supply

What sort of injuries?

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

http://world.honda.com/HDTV/ASIMO/

for Asimo video