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UNIT I

Fundamental of Robotics

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Industrial Robot Defined

A general-purpose, programmable machinepossessing certain anthropomorphiccharacteristics

Hazardous work environments

Repetitive work cycle

Consistency and accuracy

Difficult handling task for humans Multishift operations

Reprogrammable, flexible

Interfaced to other computer systems

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Laws of Robotics

Asimov proposed three

Laws of Robotics

Law 1: A robot may notinjure a human being orthrough inaction, allow ahuman being to come to

harm

Law 2: A robot must obeyorders given to it by humanbeings, except where such

orders would conflict with ahigher order law

Law 3: A robot must protectits own existence as long assuch protection does not

conflict with a higher orderlaw

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Robot Anatomy

Robot Anatomy mainly deals about

Robot configuration

Work envelope or robot motion

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2008 Pearson Education,Inc., Upper Saddle River,

NJ. All rights reserved. Thismaterial is protected under

all copyright laws as theycurrently exist.

No portion of this material

may be reproduced, in anyform or by any means,

without permission in writingfrom the publisher. For the

exclusive use of adopters ofthe book

Automation, ProductionSystems, and Computer-

Integrated Manufacturing,

Third Edition,by Mikell P.Groover.

Robot Anatomy

Robot manipulator - a series of joint-link combinations

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Robot Configurations

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Robot Configurations

Some of the commonly used configurations in Robotics are

Cartesian/Rectangular Gantry(3P) : These Robots are made of 3Linear joints that orient the end effector, which are usually followedby additional revolute joints.

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RECTANGULAR COORDINATES

Advantages:

They can obtain large work envelope because raveling along the x-axis, thevolume region can be increased easily.

Their linear movement allows for simpler controls.

They have high degree of mechanical rigidity, accuracy, and repeatability due

o their structure.

They can carry heavy loads because the weight-lifting capacity does not varyat different locations withing the work envelope.

Disadvantages:

They makes maintenance more difficult for some models with overhead drivemechanisms and control equipment.

Access to the volume region by overhead crane or other material-handlingequipment may be impaired by the robot-supporting structure.

Their movement is limited to one direction at a time.

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Application:

Pick-and-place Operations.

Adhesive Applications(mostly Long And Straight).

Assembly and Subassembly(mostly Straight).

Automated Loading CNC Lathe And Milling Operations.

Nuclear Material Handling.

Welding.

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Robot Configurations (contd)

Cylindrical (R2P): Cylindrical coordinate Robots have 2prismatic joints and one revolute joint.

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Advantage:

Their vertical structure conserves floor space.

Their deep horizontal reach is useful for far-reaching operations.

Their capacity is capable of carrying large payloads.

Disadvantage:

Their overall mechanical rigidity is lower than that of the rectilinearrobots because their rotary axis must overcome inertia.

Their repeatability and accuracy are also lower in the direction ofrotary motion.

Their configuration requires a more sophisticated control system

than the rectangular robots.

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Robot Configurations (contd)

Spherical joint (2RP): They follow a spherical coordinatesystem, which has one telescoping arm that can be raised orlowered about the horizontal pivot.

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Applications:

Die casting Dip coating

Forging

Glass handling

Heat treating Injection molding

Machine tool handling

Material transfer

Parts cleaning

Press loading

Stacking and unsticking.

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Robot Configurations (contd)

Articulated/anthropomorphic(3R) :An articulated robotsjoints are all revolute, similar to a humans arm.

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Robot Configurations (contd)

Selective Compliance Assembly Robot Arm (SCARA)(2R1P): They have two revolute joints that are parallel andallow the Robot to move in a horizontal plane, plus anadditional prismatic joint that moves vertically

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WRIST

Typically has 3 degrees of freedom Rollinvolves rotating the wrist about the

arm axis

Pitchup-down rotation of the wrist Yawleft-right rotation of the wrist

End effector is mounted on the wrist

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WRIST MOTIONS