Robotics Pp t

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ROBOTICSROBOTICS

Industrial Robots Definition

A robot is a programmable arm simulator

“A robot is a re-programmable, multifunction manipulator

designed to move material, parts, tools, or special devices

through variable programmed motions for the performance ofa variety of tasks”

Robot Institute of America



– Arm or Manipulator

– End effectors

– Drive Mechanism

– ontroller

– ustom features! e"g" sensors and transducers

Main Components of Industrial Robots



RoboticsRobotics TerminologyTerminology

Link: A rigid piece of material connecting joints in a robot.

Joint: The device which allows relative motion between two adjoining

lins in a robot.

A robot joint is a mechanism thatA robot joint is a mechanism thatpermits relative movement betweenpermits relative movement between

parts of a robot arm. The joints of aparts of a robot arm. The joints of a

robot are designed to enable therobot are designed to enable therobot to move its end-effectors alongrobot to move its end-effectors along

a path from one position to anothera path from one position to another

as desired.as desired.



The Robotic !ovementsThe Robotic !ovements

The basic movements required for aThe basic movements required for adesired motion of most industrial robotsdesired motion of most industrial robotsare:are:

Rotational movement:Rotational movement: This enables theThis enables therobot to place its arm in any direction on arobot to place its arm in any direction on a

horizontal planehorizontal plane..

Radial Radial movement:movement: This enables the robot toThis enables the robot tomove its end-effectors radially to reach distantmove its end-effectors radially to reach distantpoints.points.

Vertical movement:Vertical movement: This enables the robotThis enables the robot



The Robotic "ointsThe Robotic "oints

Types of "OI#TS

$% &inear "oint '&% (% Rotational "oint 'R%

)% Twisting "oint 'T% *% Revolving "oint '+%

$% &inear "oints are also nown as sliding as well asare also nown as sliding as well as Prismatic Prismatic joints joints '&%'&%

They are calledThey are called prismatic prismatic beca,se the cross section of the joint isbeca,se the cross section of the joint is

considered as a generali-ed prism. They permit lins to move in a linearconsidered as a generali-ed prism. They permit lins to move in a linear

relationship.relationship.

Revolute jointsRevolute joints permit only ang,lar motion between lins. Their variationspermit only ang,lar motion between lins. Their variations

incl,deincl,de

Rotational jointRotational joint 'R%'R%

Twisting jointTwisting joint 'T%'T%

Revolving jointRevolving joint '+%'+%

A robot joint



AA rotational joint rotational joint !"!"

is identified by its motion# rotation aboutis identified by its motion# rotation aboutan a$is perpendicular to the adjoiningan a$is perpendicular to the adjoining

links.links.AA twisting joint twisting joint T"T"

is also a rotational joint# where theis also a rotational joint# where the

rotation takes place about an a$isrotation takes place about an a$isthat is parallel to both adjoiningthat is parallel to both adjoining

links.links.



AA revolving joint revolving joint %"%"

is another rotational joint# where the rotationis another rotational joint# where the rotation

takes place perpendicular to one another attakes place perpendicular to one another atthis kind of joint. The rotation involvesthis kind of joint. The rotation involves

revolution of one link about another.revolution of one link about another.



/rist !ovement

The /rist movement is designed to enable the robot to orient the end

effector properly with respect to the tas to be performed.

0g. 1,man hand

To solve the orientation problem2 the wrist is normally provided with ,pto )

3O4.

$% /rist Roll5 which involves rotation of the wrist mechanism abo,t the

arm a6is. Also called as wrist swivel.

(% /rist 7itch5 If the wrist roll is in its center position 2 the pitch wo,ldinvolve the ,p and down rotation of the wrist. Also called as wrist bend.

)% /rist 8aw5 If the wrist roll is in its center position of its range2 wrist yaw

wo,ld involve the right or left rotation of the wrist.



DOF degrees-of-freedom: can be defined as the n,mberof independent motions a device can mae. 'Also called

mobilit y%

five degrees of freedom

RoboticsRobotics TerminologyTerminology



Accuracy 9The ability of a robot to go to the specified position

witho,t maing a mistae.

9It is impossible to position a machine e6actly.9 Acc,racy is therefore defined as the ability of the robot to

position itself to the desired location with the minimal

error ',s,ally (: µm%.

Repeatability 9The ability of a robot to repeatedly position itself when

ased to perform a tas m,ltiple times.9 Acc,racy is an absol,te concept2 repeatability is relative.

9 A robot that is repeatable may not be very acc,rate2 visaversa.



"oint #otation Scheme

7hysical config,ration of the robot manip,lator can be described by

means of a joint notation scheme .

Considering the arm and body joints first2 the letters can be ,sed todesignate the partic,lar robot config,ration starting with the joint

closest to the base and proceeding to the joint config,ration that

connects to the wrist.

!obot configuration!obot configuration &ymbol&ymbol

'olar configuration'olar configuration T!(T!(

)ylindrical configuration)ylindrical configuration T((#(T(#(%(T((#(T(#(%(

)artesian configuration)artesian configuration ((((((

*oint arm configuration*oint arm configuration T!!# %%!T!!# %%!



ROBOT C&ASSI4ICATIO#ROBOT C&ASSI4ICATIO#

$% 3epending on Config,ration

(% 3epending on type of control system

)% 4i6ed or variable se;,ence robot

*% 3epending ,pon generation

:% Servo < nonservo robots

=% 7oint to 7oint or contin,o,s controlling robots




)lassification +ased on 'hysical)lassification +ased on 'hysical

)onfiguration:)onfiguration:

,. )artesian configuration,. )artesian configuration

. )ylindrical configuration. )ylindrical configuration

.. 'olar configuration'olar configuration

/. *oint-arm configuration/. *oint-arm configuration

0. &)A!A0. &)A!A




)artesian )onfiguration:)artesian )onfiguration:!obots with )artesian configurations!obots with )artesian configurations

consists of links connected by linearconsists of links connected by linear

joints (". 1antry robots are joints (". 1antry robots are)artesian robots (((".)artesian robots (((".



Cartesian RobotsCartesian Robots

A robot with ) prismatic joints

> the a6es consistent with a

Cartesian coordinate system.

Commonly ,sed for9pic and place wor9assembly operations

9handling machine tools9arc welding



Cartesian RobotsCartesian Robots Advantages: Advantages:

ability to do straight line insertions into furnaces.ability to do straight line insertions into furnaces.

easy computation and programming.easy computation and programming.

most rigid structure for given length.most rigid structure for given length.

Disadvantages:Disadvantages:

requires large operating volume.requires large operating volume.

e$posed guiding surfaces require covering ine$posed guiding surfaces require covering in

corrosive or dusty environments.corrosive or dusty environments.ccan only reach front of itself an only reach front of itself

a$es hard to seala$es hard to seal



ROBOT C&ASSI4ICATIO#ROBOT C&ASSI4ICATIO#)ylindrical )onfiguration:)ylindrical )onfiguration:

!obots with cylindrical configuration have!obots with cylindrical configuration have

one rotary !" joint at the base andone rotary !" joint at the base and

linear (" joints succeeded to connect thelinear (" joints succeeded to connect the

links.links.



Cylindrical RobotsCylindrical Robots

A robot with ( prismatic joints

and a rotary joint > the a6es

consistent with a cylindrical

coordinate system.

Commonly ,sed for9handling at die5casting

machines9assembly operations9handling machine tools9spot welding



Advantages: Advantages:can reach all around itself can reach all around itself

rotational a$is easy to sealrotational a$is easy to seal

relatively easy programmingrelatively easy programming

rigid enough to handle heavy loads through large workingrigid enough to handle heavy loads through large working

spacespacegood access into cavities and machine openingsgood access into cavities and machine openings


can2t reach above itself can2t reach above itself

linear a$es is hard to seallinear a$es is hard to sealwon3t reach around obstacleswon3t reach around obstacles

e$posed drives are difficult to cover from dust and liquidse$posed drives are difficult to cover from dust and liquids

Cylindrical RobotsCylindrical Robots



ROBOT C&ASSI4ICATIO#ROBOT C&ASSI4ICATIO#'olar'olar

)onfiguration:)onfiguration:'olar robots have'olar robots havea work space ofa work space ofspherical shapespherical shape..

1enerally# the arm1enerally# the armis connected to theis connected to thebase with abase with atwisting T" jointtwisting T" jointand rotatory !"and rotatory !"

and linear ("and linear (" joints follow. joints follow.




The designation of the arm for thisThe designation of the arm for this

configuration can be T!( or T!!.configuration can be T!( or T!!.

!obots with the designation T!( are!obots with the designation T!( are

also calledalso called spherical robotsspherical robots. Those. Those

with the designation T!! are alsowith the designation T!! are also

calledcalled articulated robotsarticulated robots. An. An

articulated robot more closelyarticulated robot more closelyresembles the human arm.resembles the human arm.




*oint-arm )onfiguration:*oint-arm )onfiguration:

The jointed-arm is a combination ofThe jointed-arm is a combination of

cylindrical and articulatedcylindrical and articulated

configurations. The arm of the robotconfigurations. The arm of the robot

is connected to the base with ais connected to the base with a

twisting joint. The links in the armtwisting joint. The links in the arm

are connected by rotatory joints.are connected by rotatory joints.4any commercially available robots4any commercially available robots

have this configuration.have this configuration.



Artic,lated Robots Artic,lated Robots

A robot with at least ) rotary

joints.

Commonly ,sed for9assembly operations9welding9weld sealing

9spray painting9handling at die casting or

fettling machines



Advantages: Advantages:

all rotary joints allows for ma$imum fle$ibilityall rotary joints allows for ma$imum fle$ibility

any point in total volume can be reached.any point in total volume can be reached.

all joints can be sealed from the environment.all joints can be sealed from the environment.


e$tremely difficult to visualize# control# ande$tremely difficult to visualize# control# and

program.program.

restricted volume coverage.restricted volume coverage.

low accuracylow accuracy

Artic,lated Robots Artic,lated Robots



SCARASCARA ''SSelectiveelective C C omplianceompliance

A Articulated rticulated

R R obotobot

A Armrm

) )

RobotsRobots

A robot with at least ( parallel

rotary joints.

Commonly ,sed for9pic and place wor9assembly operations



Advantages: Advantages:

high speed.high speed.

height a$is is rigidheight a$is is rigid

large work area for floor spacelarge work area for floor space

moderately easy to program.moderately easy to program.


limited applicationslimited applications..

ways to reach point ways to reach point

difficult to program off-linedifficult to program off-line

highly comple$ armhighly comple$ arm

SCARASCARA ''SSelectiveelective C C omplianceompliance

A Articulated rticulated

R R obotobot

A Armrm

) )

RobotsRobots



Spherical<7olar RobotsSpherical<7olar Robots

A robot with $ prismatic joint

and ( rotary joints > the a6es

consistent with a polar

coordinate system.

Commonly ,sed for9handling at die casting or

fettling machines9handling machine tools9arc<spot welding



Advantages Advantages::

large working envelope.large working envelope.

two rotary drives are easily sealed againsttwo rotary drives are easily sealed against

liquids5dust.liquids5dust.

DisadvantagesDisadvantages::

comple$ coordinates more difficult to visualize#comple$ coordinates more difficult to visualize#

control# and program.control# and program.

e$posed linear drive.e$posed linear drive.

low accuracy.low accuracy.

Spherical<7olar RobotsSpherical<7olar Robots




)lassification +ased on )ontrol)lassification +ased on )ontrol

&ystems:&ystems:

6 ,. 'oint-to-point 'T'" control robot,. 'oint-to-point 'T'" control robot

6 . )ontinuous-path )'" control robot. )ontinuous-path )'" control robot

6 . )ontrolled-path robot. )ontrolled-path robot

7 i t t 7 i t C t l R b t7 i t t 7 i t C t l R b t



7oint to 7oint Control Robot7oint to 7oint Control Robot

'7T7%'7T7%

The 'T' robot is capable of moving fromThe 'T' robot is capable of moving fromone point to another point.one point to another point.

The locations are recorded in the controlThe locations are recorded in the controlmemory. 'T' robots do not control thememory. 'T' robots do not control the

path to get from one point to the ne$tpath to get from one point to the ne$tpoint.point.

)ommon applications include:)ommon applications include:6 component insertioncomponent insertion

6 spot weldingspot welding6 hole drillinghole drilling6 machine loading and unloadingmachine loading and unloading6 assembly operationsassembly operations



Contin,o,s57ath Control Robot 'C7%Contin,o,s57ath Control Robot 'C7%

The )' robot is capable of performing movementsThe )' robot is capable of performing movementsalong the controlled path. 7ith )' from onealong the controlled path. 7ith )' from onecontrol# the robot can stop at any specified pointcontrol# the robot can stop at any specified pointalong the controlled path.along the controlled path.

All the points along the path must be storedAll the points along the path must be stored

e$plicitly in the robot2s control memory.e$plicitly in the robot2s control memory.Applications &traight-line motion is the simplestApplications &traight-line motion is the simpleste$ample for this type of robot. &ome continuous-e$ample for this type of robot. &ome continuous-path controlled robots also have the capability topath controlled robots also have the capability tofollow a smooth curve path that has been definedfollow a smooth curve path that has been definedby the programmer. 8n such cases theby the programmer. 8n such cases the

programmer manually moves the robot armprogrammer manually moves the robot armthrough the desired path and the controller unitthrough the desired path and the controller unitstores a large number of individual point locationsstores a large number of individual point locationsalong the path in memoryalong the path in memory ((teach-inteach-in).).



Contin,o,s57ath Control Robot 'C7%Contin,o,s57ath Control Robot 'C7%

Typical applications include:Typical applications include:

6 spray paintingspray painting

6 finishingfinishing

6 gluinggluing

6 arc welding operationsarc welding operations



Controlled57ath RobotControlled57ath Robot

8n controlled-path robots# the control equipment8n controlled-path robots# the control equipmentcan generate paths of different geometry such ascan generate paths of different geometry such asstraight lines# circles# and interpolated curvesstraight lines# circles# and interpolated curveswith a high degree of accuracy. 1ood accuracywith a high degree of accuracy. 1ood accuracycan be obtained at any point along the specifiedcan be obtained at any point along the specifiedpath.path.

9nly the start and finish points and the path9nly the start and finish points and the path

definition function must be stored in the robot2sdefinition function must be stored in the robot2scontrol memory. 8t is important to mention thatcontrol memory. 8t is important to mention thatall controlled-path robots have a servo capabilityall controlled-path robots have a servo capabilityto correct their path.to correct their path.



Robot Specifications

)haracteristics)haracteristics nitsnits

;o of A$es;o of A$es ;umberseg ,#";umberseg ,#"

4a$ speed5cycle4a$ speed5cycle

timetime

mm5secmm5sec

(oad carrying(oad carrying

capacity pay load"capacity pay load"<g<g

!each = stroke!each = stroke mmmmTotal orientationTotal orientation >egrees>egrees

!epeatability!epeatability ----

' i i = A' i i = A

Robotics Pp t

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