Lec4 Robot Classification

ROBOT CLASSIFICATION
OBJECTIVES:
BE AWARE OF ROBOT CLASSIFICATION.
BE ACQUAINTED WITH MANIPULATOR ARM GEOMETRY.
UNDERSTAND THE DEGREES OF FREEDOM OF A ROBOTIC

SYSTEM.
RECOGNIZE THE TYPE OF POWER SOURCES USED IN

CURRENT ROBOTS.
BE FAMILIAR WITH TYPE OF MOTION.
KNOW A ROBOTS PATH CONTROL.
UNDERSTAND THE INTELLIGENCE LEVEL OF ROBOTS.

CLASSIFICATION: CLASSIFIED INTO SIX CATEGORIES
ARM GEOMETRY: RECTANGULAR;CYLINDIRICAL;SPHERICAL;

JOINTED-ARM(VERTICAL);JOINED-ARM(HORIZONTAL).
DEGREES OF FREEDOM: ROBOT ARM; ROBOT WRIST.
POWER SOURCES: ELECTRICAL;PNEUMATIC;HYDRAULIC;ANY

COMBINATION.
TYPE OF MOTION: SLEW MOTION; JOINT-INTERPOLATION;

STRAIGHT-LINE INTERPOLATION; CIRCULAR INTERPOLATION.
PATH CONTROL: LIMITED SEQUENCE; POINT-TO-POINT;

CONTINOUS PATH; CONTROLLED PATH.
INTELLLIGENCE LEVEL: LOW-TECHNOLOGY(NONSERVO); HIGH-

TECHONOLOGY(SERVO).
ARM GEOMETRY
ROBOT MUST BE ABLE TO REACH A POINT IN SPACE WITHIN THREE
AXES BY MOVING FORWARD AND BACKWARD, TO THE LEFT AND
RIGHT, AND UP AND DOWN.
ROBOT MANIPULATOR MAY BE CLASSIFIED ACCORDING TO THE TYPE

OF MOVEMENT NEEDED TO COMPLETE THE TASK.
RECTANGULAR-COORDINATED:
- HAS THREE LINEAR AXES OF MOTION.

- X REPRESENTSD LEFT AND RIGHT MOTION
- Y DESCRIBES FORWARD AND BACKWARD MOTION.
- Z IS USED TO DEPICT UP-AND-DOWN MOTION.
THE WORK ENVELOPE OF A RECTANGULAR ROBOT IS A CUBE OR

RECTANGLE, SO THAT ANY WORK PERFORMED BY ROBOT MUST ONLY
INVOLVE MOTIONS INSIDE THE SPACE.
RECTANGULAR COORDINATES
ADVANTAGES:
THEY CAN OBTAIN LARGE WORK ENVELOPE BECAUSE RAVELLING ALONG THE X-
AXIS, THE VOLUME 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 VARY AT DIFFERENT LOCATIONS WITHING THE WORK ENVELOPE.
DISADVANTAGES:
THEY MAKES MAINTENANCE MORE DIFFICULT FOR SOME MODELS WITH

OVERHEAD DRIVE MECHANISMS AND CONTROL EQUIPMENT.
ACCESS TO THE VOLUME REGION BY OVERHEAD CRANE OR OTHER MATERIAL-

HANDLING EQUIPMENT MAY BE IMPAIRED BY THE ROBOT-SUPPORTING
STRUCTURE.
THEIR MOVEMENT IS LIMITED TO ONE DIRECTION AT A TIME.

APPLICATION:
PICK-AND-PLACE OPERATIONS.
ADHESIVE APPLICATIONS(MOSTLY LONG AND STRAIGHT).
ADVANCED MUNITION HANDLING.
ASSEMBLY AND SUBASSEMBLY(MOSTLY STRAINGHT).
AUTOMATED LOADING CNC LATHE AND MILLING

OPERATIONS.
NUCLEAR MATERIAL HANDLING.
WELDING.
CYLINDRICAL-COORDINATED
HAS TWO LINEAR MOTIONS AND ONE ROTARY MOTION.
ROBOTS CAN ACHIEVE VARIABLE MOTION.
THE FIRST COORDINATE DESCRIBE THE ANGLE THETA OF BASE

ROTATION--- ABOUT THE UP-DOWN AXIS.
THE SECOND COORDINATE CORRESPOND TO A RADICAL OR Y--- IN OUT

MOTION AT WHATEVER ANGLE THE ROBOT IS POSITIONED.
THE FINAL COORDINATE AGAIN CORRESPONDS TO THE UP-DOWN Z

POSITION.
ROTATIONAL ABILITY GIVES THE ADVANTAGE OF MOVING RAPIDLY TO

THE POINT IN Z PLANE OF ROTATION.
RESULTS IN A LARGER WORK ENVELOPE THAN A RECTANGULAR ROBOT

MANIPULATOR.
SUITED FOR PICK-AND-PLACE OPERATIONS.

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

RECTILINEAR ROBOTS BECAUSE THEIR ROTARY AXIS MUST OVERCOME
INERTIA.
THEIR REPEATABILITY AND ACCURACY ARE ALSO LOWER IN THE

DIRECTION OF ROTARY MOTION.
THEIR CONFIGURATION REQUIRES A MORE SOPHISTICATED CONTROL

SYSTEM THAN THE RECTANGULAR ROBOTS.
APPLICATION:
ASSEMBLY
COATING APPLICATIONS.
CONVEYOR PALLET TRANSFER.
DIE CASTING.
FOUNDARY AND FORGING APPLICATIONS.
INSPECTION MOULDING.
INVESTMENT CASTING.
MACHINE LOADING AND UNLOADING.
SPHERICAL COORDINATED
HAS ONE LINEAR MOTION AND TWO ROTARY MOTIONS.

THE WORK VOLUME IS LIKE A SECTION OF SPHERE.
THE FIRST MOTION CORRESPONDS TO A BASE ROTATION
ABOUT A VERTICAL AXIS.
THE SECOND MOTION CORRESPONDS TO AN ELBOW
ROTATION.
THE THIRD MOTION CORRESPONDS TO A RADIAL, OR IN-OUT,
TRANSLATION.
A SPHERICAL-COORDINATED ROBOTS PROVIDES A LARGER
WORK ENVELOPE THAN THE RECTILINEAR OR CYLINDIRICAL
ROBOT.
DESIGN GIVES WEIGHT LIFTING CAPABILITIES.
ADVANTAGES AND DISADVANTAGES SAME AS CYLINDIRICAL-
COORDINATED DESIGN.
APPLICATIONS:
DIE CASTING
DIP COATING
FORGING
GLASS HANDLING
HEAT TREATING
INJECTION MOLDING
MACHINE TOOL HANDLING
MATERIAL TRANSFER
PARTS CLEANING
PRESS LOADING
STACKING AND UNSTICKING.
DEGREES OF FREEDOM
THE DEGREE OF FREEDOM OR GRIP OF A ROBOTIC SYSTEM CAN BE COMPARED

TO THE WAY IN WHICH THE HUMAN BODY MOVES.
FOR EACH DEGREE OF FREEDOM A JOINT IS REQUIRED.
THE DEGREES OF FREEDOM LOCATED IN THE ARM DEFINE THE

CONFIGURATION.
EACH OF THE FIVE BASIC MOTION CONFIGURATIONS DISCUSS PREVIOUSLY

UTILIZES THREE DEGREES OF FREEDOM IN THE ARM.
THREE DEGREES OF FREEDOM LOCATED IN THE WRIST GIVE THE END

EFFECTOR ALL THE FLEXIBILITY.
A TOTAL OF SIX DEGREES OF FREEDOM IS NEEDED TO LOCATE A ROBOTS HAND

AT ANY POINT IN ITS WORK SPACE.
ALTHOUGH SIX DEGREES OF FREEDOM ARE NEEDED FOR MAXIMUM

FLEXIBILITY, MOST ROBOT EMPLOYEE ONLY THREE TO FIVE DEGREES OF
FREEDOM.
THE MORE THE DEGREES OF FREEDOM, THE GREATER IS THE COMPLEXITY OF

MOTIONS ENCOUNTERED.
DEGREES OF FREEDOM (CONTD.)
THE THREE DEGREES OF FREEDOM LOCATED IN THE ARM OF A
ROBOTIC SYSTEM ARE:
THE ROTATIONAL REVERSE: IS THE MOVEMENT OF THE ARM ASSEMBLY

ABOUT A ROTARY AXIS, SUCH AS LEFT-AND-RIGHT SWIVEL OF THE
ROBOTS ARM ABOUT A BASE.
THE RADIAL TRAVERSE: IS THE EXTENSION AND RETRACTION OF THE ARM
OR THE IN-AND-OUT MOTION RELATIVE TO THE BASE.
THE VERTICAL TRAVERSE: PROVIDES THE UP-AND-DOWN MOTION OF THE
ARM OF THE ROBOTIC SYSTEM.
THE THREE DEGREES OF FREEDOM LOCATED IN THE WRIST, WHICH

BEAR THE NAMES OF AERONAUTICAL TERMS, ARE
PITCH OR BEND: IS THE UP-AND-DOWN MOVEMENT OF THE WRIST.

YAW: IS THE RIGHT-AND-LEFT MOVEMENT OF THE WRIST.
ROLL OR SWIVEL: IS THE ROTATION OF THE HAND.
POWER SOURCES
THE FOUR POWER SOURCES USED IN CURRENT ROBOTS ARE:
ELECTRIC: ALL ROBOTS USE ELECTRICITY AS THE PRIMARY SOURCE OF

ENERGY.
ELECTRICITY TURNS THE PUMPS THAT PROVIDE HYDRAULLIC AND PNEUMATIC

PRESSURE.
IT ALSO POWERS THE ROBOT CONTROLLER AND ALL THE ELECTRONIC
COMPONENTS AND PERIPHERAL DEVICES.
IN ALL ELECTRIC ROBOTS, THE DRIVE ACTUATORS, AS WELL AS THE CONTROLLER,
ARE ELECTRICALLY POWERED.
BECAUSE ELECTRIC ROBOT DO NOT REQUIRE A HYDRAULIC POWER UNIT, THEY
CONSERVE FLOOR SPACE AND DECREASE FACTORY NOISE.
NO ENERGY CONVERSION IS REQUIRED.
PNEUMATIC: THESE ARE GENERALLY FOUND IN RELATIVELY LOW-COST

MANIPULATORS WITH LOW LOAD CARRYING CAPACITY.
PNEUMATIC DRIVES HAVE BEEN USED FOR MANY YEARS FOR POWERING SIMPLE
STOP-TO-STOP MOTIONS.
IT IS INHERENTLY LIGHT WEIGHT, PARTICULARLY WHEN OPERATING PRESSURES
ARE MODERATE.
HYDRAULIC: ARE EITHER LINEAR POSITION ACTUATORS OR A ROTARY
VANE CONFIGURATION.
HYDRAULIC ACTUATORS PROVIDE A LARGE AMOUNT OF POWER FOR A

GIVEN ACTUATOR.
THE HIGH POWER-TO-WEIGHT RATIO MAKES THE HYDRAULIC

ACTUATOR AN ATTRACTIVE CHOICE FOR MOVING MODERATE TO HIGH
LOADS AT REASONABLE SPEEDS AND MODERATE NOISE LEVEL.
HYDRAULIC MOTORS USUALLY PROVIDE A MORE EFFICIENT WAY OF

ENERGY TO ACHIEVE A BETTER PERFORMANCE, BUT THEY ARE
EXPENSIVE AND GENERALLY LESS ACCURATE.
TYPES OF MOTION
A ROBOT MANIPULATOR CAN MAKE FOUR TYPES OF MOTION IN

TRAVELLING FROM ONE POINT TO ANOTHER IN THE WORKPLACE:
SLEW MOTION : SIMPLEST TYPE OF MOTION. ROBOT IS COMMANDED TO

TRAVEL FROM ONE POINT TO ANOTHER AT DEFAULT SPEED.
JOINT-INTERPOLATED MOTION: REQUIRES THE ROBOT CONTROLLER TO

CALCULATE THE TIME IT WILL TAKE EACH JOINT TO REACH ITS DESTINATION
AT THE COMMANDED SPEED.
STRAIGHT-LINE INTERPOLATION MOTION: REQUIRES THE END OF THE END

EFFECTOR TO TRAVEL ALONG A STRAIGHT PATH DETERMINE IN RECTANGULAR
COORDINATES.
USEFUL IN APPLICATIONS SUCH AS ARC WELDING, INSERTING PINS INTO HOLES, OR

LAYING MATERIAL ALONG A STRAIGHT PATH.
CIRCULAR INTERPOLATION MOTION: REQUIRES THE ROBOT CONTROLLER TO

DEFINE THE POINTS OF A CIRCLE IN THE WORKPLACE BASED ON A MINIMUM
OF THREE SPECIFIED POSITIONS.
CIRCULAR INTERPOLATION PRODUCES A LINEAR APPROXIMATION OF THE CIRCLE AND

IS MORE READILY AVAILABLE USING A PROGRAMMING LANGUAGE RATHER THAN
MANUAL OR TEACH PENDANT TECHNIQUES.
PATH CONTROL
COMMERCIALLY AVAILABLE INDUSTRIAL ROBOTS CAN BE CLASSIFIED
INTO FOUR CATEGORIES ACCORDING TO THE PATH CONTROL SYSTEM.
LIMITED-SEQUENCE: DO NOT USE SERVO-CONTROL TO INDICATE RELATIVE

POSITIONS OF THE JOINTS.
THEY ARE CONTROLLED BY SETTING LIMIT SWITCHES AND/OR MECHANICAL STOPS

TOGETHER WITH A SEQUENCER TO COORDINATE AND TIME THE ACTUATION OF THE
JOINTS.
WITH THIS METHOD OF CONTROL, THE INDIVDUAL JOINTS CAN ONLY BE MOVED TO
THEIR EXTREME LIMITS OF TRAVEL.
POINT-TO-POINT: THESE ROBOTS ARE MOST COMMON AND CAN MOVE FROM
ONE SPECIFIED POINT TO ANOTHER BUT CANNOT STOP AT ARBITRARY POINTS
NOT PREVIOUSLY DESIGNATED.
CONTROLLED PATH: IS A SPECIALIZED CONTROL METHOD THAT IS A PART OF

GENERAL CATEGORY OF A POINT-TO-POINT ROBOT BUT WITH MORE PRECISE
CONTROL.
THE CONTROLLED PATH ROBOT ENSURES THAT THE ROBOT WILL DESCRIBE THE RIGHT
SEGMENT BETWEEN TWO TAUGHT POINTS.
CONTROLLED-PATH IS A CALCULATED METHOD AND IS DESIRED WHEN THE
MANIPULATOR MUST MOVE IN THE PERFECT PATH MOTION.
CONTINUOUS PATH: IS AN EXTENSION OF THE POINT-TO-POINT
METHOD. THIS INVOLVES THE UTILIZATION OF MORE POINTS
AND ITS PATH CAN BE ARC, A CIRCLE, OR A STRAIGHT LINE.
BECAUSE OF THE LARGE NUMBER OF POINTS, THE ROBOT IS CAPABLE

OF PRODUCING SMOOTH MOVEMENTS THAT GIVE THE APPEARANCE
OF CONTINUOUS OR CONTOUR MOVEMENT.
INTELLIGENCE LEVEL
THE INTELLIGENT CONTROL ROBOT IS CAPABLE OF PERFOMING SOME OF THE
FUNCTIONS AND TASKS CARRIED OUT BY HUMAN BEINGS.
IT CAN DETECT CHANGES IN THE WORK ENVIRONMENT BY MEANS OF SENSORY

PERCEPTION.
INTELLIGENT ROBOT IS EQUIPPED WITH A VARIETY OF SENSORS AND SENSOR

APPARATUS PROVIDING VISUAL (COMPUTER VISION) AND TACTILE
(TOUCHING) CAPABILITIES TO RESPOND INSTANTLY TO VARIABLE
SITUATIONS.
MUCH LIKE HUMANS, THE ROBOT OBSERVES AND EVALUATES THE IMMEDIATE
ENVIRONMENT BY PERCEPTION AND PATTERN RECOGNITION.
BECAUSE ITS OPERATION IS SO COMPLEX, POWERFUL COMPUTERS ARE

REQUIRED TO CONTROL ITS MOVEMENTS AND MORE- SOPHISTICATED
SENSING DEVICES TO RESPOND TO ITS ACTIONS.
EXTENSIVE RESEARCH HAS BEEN AND STILL CONCERNED WITH HOW TO EQUIP
ROBOTS WITH SEEING EYES AND TACTILE FINGERS.
ARTIFICIAL INTELLIGENCE (AI) THAT WILL ENABLE THE ROBOTS TO RESPOND,

ADAPT, REASON, AND MAKE DECISIONS TO REACT TO CHANGE IS ALSO AN
INHERENT CAPABILITY OF THE INTELLIGENT ROBOT.
SUMMARY
INTRODUCES THE GENERAL CONCEPTS OF ROBOT CLASSIFICATION.
PROVIDED OVERVIEW OF ALL TYPES OF ROBOT ARM GEOMETRY AND

STYLES, CONSIDERING DEGREES OF FREEDOM, POWER SOURCES,
CONTROL SYSTEMS, AND PATH CONTROL.
THE ARM GEOMETRY IS AVAILABLE IN FIVE BASIC CONFIGURATIONS:

RECTANGULAR, CYLINDRICAL, SPHERICAL, JOINTED-ARM, AND SCARA.
THE THREE DEGRESS OF FREEDOM LOCATED IN THE ARM OF ROBOT

SYSTEM ARE THE ROTATIONAL TRAVERSE, THE RADIAL TRAVERSE, AND
THE VERTICAL TRAVERSE.
THE THREE DEGREES OF FREEDOM LOCATED IN THE WRIST ARE PITCH,

YAW, AND ROLL.
THE FOUR POWER SOURCES USED IN THE CURRENT ROBOTS ARE

ELECTRIC, HYDRAULIC, PNEUMATIC, AND ELECTROMECHANICAL.
SUMMARY (CONTD.)
THERE ARE FOUR TYPES OF MOTION THAT A ROBOT MANIPULATOR

CAN MAKE IN TRAVELING FROM ONE POINT TO ANOTHER IN THE
WORKPLACE: SLEW, JOINT-INTEROLATED, STRAIGHT LINE
INTERPOLATION, CIRCULAR.
THERE ARE FOUR TYPES OF PATH CONTROLS OF ROBOTS: LIMITED-

SEQUENCE, POINT-TO-POINT, CONTROLLED-PATH, AND CONTINUOUS
PATH.
ROBOT SYSTEMS ARE USUALLY CLASSIFIED AS HIGH-TECHNOLOGY

AND LOW-TECHNOLOGY GROUP.

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ROBOT CLASSIFICATION

BE AWARE OF ROBOT CLASSIFICATION.

BE ACQUAINTED WITH MANIPULATOR ARM GEOMETRY.

UNDERSTAND THE DEGREES OF FREEDOM OF A ROBOTIC

RECOGNIZE THE TYPE OF POWER SOURCES USED IN

BE FAMILIAR WITH TYPE OF MOTION.

KNOW A ROBOTS PATH CONTROL.

UNDERSTAND THE INTELLIGENCE LEVEL OF ROBOTS.

ARM GEOMETRY: RECTANGULAR;CYLINDIRICAL;SPHERICAL;

DEGREES OF FREEDOM: ROBOT ARM; ROBOT WRIST.

POWER SOURCES: ELECTRICAL;PNEUMATIC;HYDRAULIC;ANY

TYPE OF MOTION: SLEW MOTION; JOINT-INTERPOLATION;

PATH CONTROL: LIMITED SEQUENCE; POINT-TO-POINT;

INTELLLIGENCE LEVEL: LOW-TECHNOLOGY(NONSERVO); HIGH-

ROBOT MANIPULATOR MAY BE CLASSIFIED ACCORDING TO THE TYPE

- HAS THREE LINEAR AXES OF MOTION.

THE WORK ENVELOPE OF A RECTANGULAR ROBOT IS A CUBE OR

THEIR LINEAR MOVEMENT ALLOWS FOR SIMPLER CONTROLS.

THEY HAVE HIGH DEGREE OF MECHANICAL RIGIDITY, ACCURACY, AND

THEY MAKES MAINTENANCE MORE DIFFICULT FOR SOME MODELS WITH

ACCESS TO THE VOLUME REGION BY OVERHEAD CRANE OR OTHER MATERIAL-

THEIR MOVEMENT IS LIMITED TO ONE DIRECTION AT A TIME.

ADHESIVE APPLICATIONS(MOSTLY LONG AND STRAIGHT).

ADVANCED MUNITION HANDLING.

ASSEMBLY AND SUBASSEMBLY(MOSTLY STRAINGHT).

AUTOMATED LOADING CNC LATHE AND MILLING

NUCLEAR MATERIAL HANDLING.

ROBOTS CAN ACHIEVE VARIABLE MOTION.

THE FIRST COORDINATE DESCRIBE THE ANGLE THETA OF BASE

THE SECOND COORDINATE CORRESPOND TO A RADICAL OR Y--- IN OUT

THE FINAL COORDINATE AGAIN CORRESPONDS TO THE UP-DOWN Z

ROTATIONAL ABILITY GIVES THE ADVANTAGE OF MOVING RAPIDLY TO

RESULTS IN A LARGER WORK ENVELOPE THAN A RECTANGULAR ROBOT

SUITED FOR PICK-AND-PLACE OPERATIONS.

THEIR VERTICAL STRUCTURE CONSERVES FLOOR SPACE.

THEIR DEEP HORIZONTAL REACH IS USEFUL FOR FAR-REACHING

THEIR CAPACITY IS CAPABLE OF CARRYING LARGE PAYLOADS.

THEIR OVERALL MECHANICAL RIGIDITY IS LOWER THAN THAT OF THE

THEIR REPEATABILITY AND ACCURACY ARE ALSO LOWER IN THE

THEIR CONFIGURATION REQUIRES A MORE SOPHISTICATED CONTROL

HAS ONE LINEAR MOTION AND TWO ROTARY MOTIONS.

THE DEGREE OF FREEDOM OR GRIP OF A ROBOTIC SYSTEM CAN BE COMPARED

FOR EACH DEGREE OF FREEDOM A JOINT IS REQUIRED.

THE DEGREES OF FREEDOM LOCATED IN THE ARM DEFINE THE

EACH OF THE FIVE BASIC MOTION CONFIGURATIONS DISCUSS PREVIOUSLY

THREE DEGREES OF FREEDOM LOCATED IN THE WRIST GIVE THE END

A TOTAL OF SIX DEGREES OF FREEDOM IS NEEDED TO LOCATE A ROBOTS HAND

ALTHOUGH SIX DEGREES OF FREEDOM ARE NEEDED FOR MAXIMUM

THE MORE THE DEGREES OF FREEDOM, THE GREATER IS THE COMPLEXITY OF

THE ROTATIONAL REVERSE: IS THE MOVEMENT OF THE ARM ASSEMBLY

THE THREE DEGREES OF FREEDOM LOCATED IN THE WRIST, WHICH

PITCH OR BEND: IS THE UP-AND-DOWN MOVEMENT OF THE WRIST.

ELECTRIC: ALL ROBOTS USE ELECTRICITY AS THE PRIMARY SOURCE OF

ELECTRICITY TURNS THE PUMPS THAT PROVIDE HYDRAULLIC AND PNEUMATIC

PNEUMATIC: THESE ARE GENERALLY FOUND IN RELATIVELY LOW-COST

HYDRAULIC ACTUATORS PROVIDE A LARGE AMOUNT OF POWER FOR A

THE HIGH POWER-TO-WEIGHT RATIO MAKES THE HYDRAULIC

HYDRAULIC MOTORS USUALLY PROVIDE A MORE EFFICIENT WAY OF

A ROBOT MANIPULATOR CAN MAKE FOUR TYPES OF MOTION IN