robotics engg intro

8/13/2019 Robotics Engg Intro

1/65

ME0506 ROBOTICS ENGG

Classification and types of robot


2/65

The word robot was coined by sciencefiction author and Nobel Prize winner Karel

Capek in the year 1920.

Word robotics was first used in the yearMay 1941 by Isaac Asimov in a science

fiction story Liar.

It came from Czech & Slovak word robotameaning self labor or hard work.


3/65


4/65

Industrial robot:The Robotics Industries Association(RIA) defines robot in the following way:

An industrial robot is a programmable, multi-

functional manipulator designed to move materials,parts, tools, or special devices through variable

programmed motions for the performance of a

variety of tasks


5/65

Robots are used in the following Areas

1. Industries

2. Medicine

3. Military

4. Space Missions5. Home


6/65

Robot Foot Ball Match
http://localhost/var/www/apps/conversion/tmp/ganga/robot%20foot%20ball%20match.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/robot%20foot%20ball%20match.WMV


7/65

Pick and Place Robot
http://localhost/var/www/apps/conversion/tmp/ganga/Pick%20and%20Place%20in%20assembling.mpghttp://localhost/var/www/apps/conversion/tmp/ganga/Pick%20and%20Place%20in%20assembling.mpg


8/65

Surgical Robot
http://localhost/var/www/apps/conversion/tmp/ganga/medical%20robot.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/medical%20robot.WMV


9/65

Military Robot
http://localhost/var/www/apps/conversion/tmp/ganga/military%20robot.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/military%20robot.WMV


10/65

Space Robot
http://localhost/var/www/apps/conversion/tmp/ganga/Robot%20on%20the%20mission.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/Robot%20on%20the%20mission.WMV


11/65
http://upload.wikimedia.org/wikipedia/commons/b/be/Robosnakes.jpg


12/65

Three Laws of Robotics:

A robot may not injure a human being, or,

through inaction, allow a human being to come

to harm. A robot must obey the orders given it by human

beings except where such orders would conflict

with the First Law. A robot must protect its own existence as long as

such protection does not conflict with the First

or Second Law.


13/65

Robotics History1946

George Devol patents a playback device for controllingmachines.

1961

Heinrich Ernst develops the MH-1, a computer

operated mechanical hand at MIT.

1961

Unimate, the company of Joseph Engleberger and

George Devoe, built the first industrial robot, thePUMA (Programmable Universal Manipulator Arm).

1966

The Stanford Research Institute creates Shakey the first

mobile robot to know and react to its own actions.


14/65

Robotics HistoryUnimate PUMA SRI Shakey
http://localhost/var/www/apps/conversion/tmp/ganga/UNIMATION%20Robot%20-%20Puma%20500.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/UNIMATION%20Robot%20-%20Puma%20500.WMV


15/65


Victor Scheinman creates the Stanford Arm. The arm's

design becomes a standard and is still influencing the

design of robot arms today.


16/65


Shigeo Hirose designs the Soft Gripper at the Tokyo

Institute of Technology. It is designed to wrap around an

object in snake like fashion.

1981

Takeo Kanade builds the direct drive arm. It is the first tohave motors installed directly into the joints of the arm. This

change makes it faster and much more accurate than

previous robotic arms.

1989

A walking robot named Genghis is unveiled by the Mobile

Robots Group at MIT.


17/65

Robotics History

1993Dante an 8-legged walking robot developed at Carnegie

Mellon University descends into Mt. Erebrus, Antarctica. Its

mission is to collect data from a harsh environment similar

to what we might find on another planet.

1994

Dante II, a more robust version of Dante I, descends into

the crater of Alaskan volcano Mt. Spurr. The mission is

considered a success.
http://localhost/var/www/apps/conversion/tmp/ganga/8%20LEG%20WALKING%20ROBOT.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/8%20LEG%20WALKING%20ROBOT.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/8%20LEG%20WALKING%20ROBOT.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/8%20LEG%20WALKING%20ROBOT.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/8%20LEG%20WALKING%20ROBOT.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/8%20LEG%20WALKING%20ROBOT.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/8%20LEG%20WALKING%20ROBOT.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/8%20LEG%20WALKING%20ROBOT.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/8%20LEG%20WALKING%20ROBOT.WMV


18/65

1996

Hondadebuts the P3.

Robotics History
http://localhost/var/www/apps/conversion/tmp/ganga/HONDA%20P3%20WALKING%20ROBOT.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/HONDA%20P3%20WALKING%20ROBOT.WMV


19/65

Robotics History

1997The Pathfinder Mission lands on Mars

1999

SONY releases theAIBO robotic pet.
http://localhost/var/www/apps/conversion/tmp/ganga/aibo%20robot.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/aibo%20robot.WMV


20/65

ASIMO (HONDA)

QRIO (SONY)

EMIEW (HITACHI)


21/65

. ASIMO Stands for Advance Step In

Innovative Mobility

The first humanoid was manufactured byHonda

Hondas ASIMO was born five years ago.

It is physically anthropomorphic.

ASIMO is almost always characterized as a

service robot.


22/65

ASIMO ROBOT
http://localhost/var/www/apps/conversion/tmp/ganga/ASIMO%20ROBOT.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/ASIMO%20ROBOT.WMV


23/65

Height 4ft 3inch (130cm)

Weight 119 pounds (54 kg)

Walking speed 1.7mph (2.7 km/h) Grasping force 0.5 kg/hand (5 fingers hand)

Actuators servomotor+harmonic speed

reducer+drive unit

Control unit walk/operating control

unit, wireless transmission


24/65

Sensors:Foot 6-axis foot area sensors

Power Rechargeable 51.8Vlithium ion battery

Operating time 1 hour


25/65

Robot serving coffee
http://localhost/var/www/apps/conversion/tmp/ganga/robot%20serving%20coffee.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/robot%20serving%20coffee.WMV


26/65

BASIC COMPONENTS

The basic components of an

industrial robot are the

ManipulatorThe end effector (which is the part

of the manipulator).

The power supplyAnd the controller.


27/65

Components of robot


28/65

Basic components of Robot


29/65

ROBOT CLASSIFICATION

Classification Based on Physical

Configuration:

1. Cartesian configuration

2. Cylindrical configuration

3. Polar configuration

4. Joint-arm configuration


30/65

Classification of the Robots


31/65


Cartesian Configuration: Robots with Cartesian configurations

consists of links connected by linear joints

(L). Gantry robots are Cartesian robots(LLL).
http://localhost/var/www/apps/conversion/tmp/ganga/CARTESIAN%20ROBOT.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/CARTESIAN%20ROBOT.WMV


32/65

Cartesian Robots

A robot with 3 prismatic joints

the axes consistent with a

Cartesian coordinate system.

Commonly used for:

pick and place work

assembly operations

handling machine toolsarc welding


33/65

Cartesian RobotsAdvantages: ability to do straight line insertions into furnaces.

easy computation and programming.

most rigid structure for given length.

Disadvantages:

requires large operating volume.

exposed guiding surfaces require covering in corrosive

or dusty environments. can only reach front of itself

axes hard to seal


34/65


Cylindrical Configuration: Robots with cylindrical configuration have

one rotary ( R) joint at the base and linear

(L) joints succeeded to connect the links.


35/65

Cylindrical Robots

A robot with 2 prismatic joints

and a rotary jointthe axes

consistent with a cylindrical

coordinate system.

Commonly used for:

handling at die-casting

machinesassembly operations

handling machine tools

spot welding
http://localhost/var/www/apps/conversion/tmp/ganga/CYLINDRICAL%20ROBOT.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/CYLINDRICAL%20ROBOT.WMV


36/65

Advantages: can reach all around itself

rotational axis easy to seal

relatively easy programming

rigid enough to handle heavy loads through large workingspace

good access into cavities and machine openings

Disadvantages:

can't reach above itself linear axes is hard to seal

wont reach around obstacles

exposed drives are difficult to cover from dust and liquids

Cylindrical Robots


37/65


Polar Configuration: Polar robots have a

work space of

spherical shape.

Generally, the arm isconnected to the

base with a twisting

(T) joint and rotatory

(R) and linear (L)

joints follow.


38/65


The designation of the arm for this

configuration can be TRL or TRR.

Robots with the designation TRL are also

called spherical robots. Those with the

designation TRR are also called

articulated robots. An articulated robot

more closely resembles the human arm.


39/65


Joint-arm Configuration:

The jointed-arm is a combination of

cylindrical and articulated configurations.

The arm of the robot is connected to the

base with a twisting joint. The links in the

arm are connected by rotatory joints. Many

commercially available robots have thisconfiguration.


40/65

Articulated Robots

A robot with at least 3 rotary

joints.

Commonly used for:assembly operations

welding

weld sealing

spray paintinghandling at die casting or

fettling machines
http://localhost/var/www/apps/conversion/tmp/ganga/Articulated%20Robot.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/Articulated%20Robot.WMV


41/65

Advantages:

all rotary joints allows for maximum flexibility

any point in total volume can be reached.

all joints can be sealed from the environment.

Disadvantages:

extremely difficult to visualize, control, and program.

restricted volume coverage.

low accuracy

Articulated Robots
http://localhost/var/www/apps/conversion/tmp/ganga/SCARA%20Robot,%20Sorting%20the%20Balls.WMV


42/65

SCARA(SelectiveCompliance

Articulated

Robot

Arm

)RobotsA robot with at least 2 parallel

rotary joints.

Commonly used for:

pick and place work

assembly operations

SCARA (S C
http://localhost/var/www/apps/conversion/tmp/ganga/SCARA%20Robot,%20Sorting%20the%20Balls.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/SCARA%20Robot,%20Sorting%20the%20Balls.WMV


43/65

Advantages:

high speed.

height axis is rigid

large work area for floor space moderately easy to program.

Disadvantages:

limited applications.

2 ways to reach point

difficult to program off-line

highly complex arm

SCARA (SelectiveCompliance

ArticulatedRobotArm)Robots

S h i l/P l R b t
http://localhost/var/www/apps/conversion/tmp/ganga/spherical%20robot.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/spherical%20robot.WMV


44/65

Spherical/Polar RobotsA robot with 1 prismatic joint and 2

rotary joints the axes consistent with

a polar coordinate system.

Commonly used for:

handling at die casting or fettling

machines

handling machine toolsarc/spot welding
http://localhost/var/www/apps/conversion/tmp/ganga/spherical%20robot.WMVhttp://localhost/var/www/apps/conversion/tmp/ganga/spherical%20robot.WMV


45/65

Advantages:

large working envelope.

two rotary drives are easily sealed against liquids/dust.

Disadvantages:

complex coordinates more difficult to visualize, control,

and program.

exposed linear drive.

low accuracy.

Spherical/Polar Robots


46/65

The Robotic Joints

The basic movements required for a desiredmotion of most industrial robots are:

1. ro tat ional movement:This enables the robotto place its arm in any direction on a horizontalplane.

2. Radialmovement :This enables the robot tomove its end-effector radially to reach distantpoints.

3. Vert ical movement:This enables the robot totake its end-effector to different heights.


47/65

Types of Joints


48/65

The Robotic Joints

These degrees of freedom, independentlyor in combination with others, define thecomplete motion of the end-effector.

These motions are accomplished bymovements of individual joints of the robotarm. The joint movements are basicallythe same as relative motion of adjoining

links. Depending on the nature of thisrelative motion, the joints are classified aspr ismat icorrevolute.


49/65

The Robotic Joints

Prismat ic join ts(L)are also known as

sliding as well as linear joints.

They are called pr ismat icbecause the

cross section of the joint is considered as

a generalized prism. They permit links to

move in a linear relationship.


50/65

The Robotic Joints

Revo lute jointspermit only angular

motion between links. Their variations

include:

Rotational joint(R)

Twisting joint(T)

Revolving joint(V)


51/65

The Robotic Joints

In a pr ismat ic jo int, also known as a

sliding or linear joint (L), the links are

generally parallel to one


52/65

The Robotic Joints

A rotat ional joint (R) is identified by its

motion, rotation about an axis

perpendicular to the adjoining links. Here,

the lengths of adjoining links do notchange but the relative position of the links

with respect to one another changes as

the rotation takes place.


53/65

The Robotic Joints


54/65

The Robotic Joints

A tw is t ing jo in t(T) is also a rotationaljoint, where the rotation takes place about

an axis that is parallel to both adjoining

links.


55/65

The Robotic Joints

A robot joint is a mechanism that permits

relative movement between parts of a

robot arm. The joints of a robot are

designed to enable the robot to move itsend-effector along a path from one

position to another as desired.


56/65

Speed

The amount of distance per unit time at which the robot

can move, usually specified in inches per second or

meters per second.

The speed is usually specified at a specific load or

assuming that the robot is carrying a fixed weight.Actual speed may vary depending upon the weight carried

by the robot.

Load Bearing CapacityThe maximum weight-carrying capacity of the robot.

Robots that carry large weights, but must still be precise

are expensive.

Robotics Terminology


57/65

Accuracy

The ability of a robot to go to the specified position

without making a mistake.

It is impossible to position a machine exactly.

Accuracy is therefore defined as the ability of the robot to

position itself to the desired location with the minimalerror (usually 25 mm).

Repeatabil i ty

The ability of a robot to repeatedly position itself whenasked to perform a task multiple times.

Accuracy is an absolute concept, repeatability is relative.

A robot that is repeatable may not be very accurate, visa

versa.

Robotics Terminology

Accuracy and Repeatability


58/65

Accuracy and Repeatability

Control Resolution(CR) is the distance between

addressable points within the joint range.Number of addressable points = (joint range/2n)

where n is the number of bit assigned to thejoints range of motion

Spatial Resolution(SR) combines the controlresolutionwith the mechanicalerrors (deflection oflinks, gear backlash, etc)

SR = CR + 6 (std dev of mechanical errors)

Accuracy = SR/2

Repeatability = + 3 (std dev of mechanical errors)

Accuracy and Repeatability: Example


59/65

Accuracy and Repeatability: Example Assume robot has one linear (sliding) joint with full range of 40. The

robot control memory has a 12-bits storage capacity. The standarddeviation of mechanical errors 0.0001.

# increments (addressable points) = 2n= 212 = 4096Joint Range 40

Control Resolution (CR) = ----------------- = -------- = 0.0098

# increment 4096

Repeatability = + 3 ( std. dev . of mech errors)

= + 3 ( 0.0001) = + 0.0003

Spatial Resolution (SR) = CR + 6 (std. dev. of mech errors)

= 0.0098 + 6 (0.0001) = 0.0104

Accuracy (worst) = SR/2 = 0.0104/2 = 0.0052

Control Systems


60/65

Control Systems

The control system issimilar to those of CNCmachine tools.

In PTP,path itself is not controlled, only the final position is

controlled. All joints are driven at thesame speedbut notnecessarilysimultaneously.

In Continuous Path all joints move simultaneously, but at

different speedsto produce an accurate path

The interpolation algorithmsare more complex than CNC

(many axis) Coordinate transformationfrom end pointposition to joint motion is required for control of all non-Cartesian robots.


61/65


Classification Based on Control Systems:

1. Point-to-point (PTP) control robot

2. Continuous-path (CP) control robot

3. Controlled-path robot


62/65

Point to Point Control Robot (PTP):

The PTP robot is capable of moving from onepoint to another point.

The locations are recorded in the controlmemory. PTP robots do not control the path to

get from one point to the next point. Common applications include:

component insertion

spot welding

hole drilling machine loading and unloading

assembly operations


63/65

Continuous-Path Control Robot (CP):

The CP robot is capable of performing movements alongthe controlled path. With CP from one control, the robotcan stop at any specified point along the controlled path.

All the points along the path must be stored explicitly inthe robot's control memory. Applications Straight-line

motion is the simplest example for this type of robot.Some continuous-path controlled robots also have thecapability to follow a smooth curve path that has beendefined by the programmer. In such cases theprogrammer manually moves the robot arm through the

desired path and the controller unit stores a largenumber of individual point locations along the path inmemory (teach-in).


64/65

Continuous-Path Control Robot (CP):

Typical applications include:

spray painting

finishing

gluing

arc welding operations

C


65/65

Controlled-Path Robot:

In controlled-path robots, the control equipment cangenerate paths of different geometry such as straightlines, circles, and interpolated curves with a high degreeof accuracy. Good accuracy can be obtained at any point

along the specified path.

Only the start and finish points and the path definitionfunction must be stored in the robot's control memory. It

is important to mention that all controlled-path robotshave a servo capability to correct their path.

robotics engg intro

Documents