Download 17 MOTION CONTROL SERVO SYSTEMS

MOTION CONTROL/SERVO
SYSTEMS
A MOTION
CONTROL
SYSTEM IS
SPECIFICALLY
DESIGNED TO
CONTROL THE
MOTIONS OF
MACHINES
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MOTION CONTROL/SERVO
SYSTEMS
THE PURPOSE OF MOTION CONTROL
ON A MACHINE IS OFTEN TO
SYCHRONIZE TWO OR MORE
RELATED FUNCTIONS
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MOTION CONTROL/SERVO
SYSTEMS
MOTION
CONTROL
HARDWARE CAN
CONSIST OF
MOTORS,
AMPLIFIERS,
AND DRIVE
SYSTEMS
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MOTION CONTROL/SERVO
SYSTEMS
MOTION CONTROL
HARDWARE USES
COMPUTER AND/ OR
PLC,
PROGRAMMABLE
LOGIC
CONTROLLERS, TO
RUN ALORITHMS
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MOTION CONTROL/SERVO
SYSTEMS
PMC, PROGRAMMABLE MOTOR CONTROL
IS DEFINED AS THE APPLICATION OF
PROGRAMMABLE HARDWARE AND
SOFTWARE TO CONTROL LINEAR AND
ROTARY MOTIONS
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MOTION CONTROL/SERVO
SYSTEMS
PMC USES
INPUT
SENSORY
DEVICES,
ACTUATORS
AND OTHER
FEEDBACK
DEVICES
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MOTION CONTROL/SERVO
SYSTEMS
A MICROPROCESSOR BASED SYSTEM
WILL INCLUDE A CONTROLLER,
AMPLIFIER, ACTUATOR, AND FEEDBACK
THE CONTROLLER INPUTS A SET OF INSTRUCTIONS
INTO MEMORY AND TRANSLATES THEM INTO
ELECTRICAL SIGNALS FOR THE AMPLIFIER
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MOTION CONTROL/SERVO
SYSTEMS
A MICROPROCESSOR BASED SYSTEM
WILL INCLUDE A CONTROLLER,
AMPLIFIER, ACTUATOR, AND FEEDBACK
THE AMPLIFIER TAKES THE SIGNALS,
AMPLIFIES THEM TO CORRECT LEVELS
FOR THE ACTUATOR
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MOTION CONTROL/SERVO
SYSTEMS
A MICROPROCESSOR
BASED SYSTEM WILL
INCLUDE A
CONTROLLER,
AMPLIFIER,
ACTUATOR, AND
FEEDBACK
THE ACTUATOR
PERFORMS THE
PHYSICAL MOTION
NEEDED TO
ACCOMPLISH THE TASK
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MOTION CONTROL/SERVO
SYSTEMS
A MICROPROCESSOR BASED SYSTEM
WILL INCLUDE A CONTROLLER,
AMPLIFIER, ACTUATOR, AND FEEDBACK
FEEDBACK IS ACCOMPLISHED THROUGH
OPTICAL AND MAGNETIC ENCODERS AND
RESOLVERS WHICH PROVIDE INFORMATION
FOR ADJUSTMENTS TO THE CONTROLLER
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MOTION CONTROL/SERVO
SYSTEMS
THE PURPOSE OF
MOTION CONTROL
ON ONE OR MORE OF
THE PARAMETERS
OF POSITION,
VELOCITY,
ACCELERATION, AND
TORQUE
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MOTION CONTROL/SERVO
SYSTEMS
VELOCITY CONTROL OR SPEED
CONTROL IS QUANTIFIED WITH
REFERENCE TO LOAD, THRUST OR
TORQUE, AND SPEED REGULATION
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MOTION CONTROL/SERVO
SYSTEMS
TORQUE CONTROL
IS NEEDED TO
DETERMINE THE
APPROPRIATE
FORCE INVOVLED
INDEPENDENT OF
SPEED
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MOTION CONTROL/SERVO
SYSTEMS
POSITION CONTROL INVOVLES
THE MOTION CONTROL OF
DISPLACEMENT WITH RESPECT
TO TIME
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MOTION CONTROL/SERVO
SYSTEMS
AMPLIFIERS CAN BE
CLASSIFIED
DEPENDING ON
THE
CHARACTERISTICS
OF THEIR OUTPUT
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MOTION CONTROL/SERVO
SYSTEMS
AMPLIFIERS CAN BE CLASSIFIED DEPENDING ON THE
CHARACTERISTICS OF THEIR OUTPUT
DC AMPLIFIER IS LINEAR AND
OUTPUTS A BI-DIRECTION DC
VOLTAGE FOR POWERING A
BRUSH-TYPE DC MOTOR
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MOTION CONTROL/SERVO
SYSTEMS
AMPLIFIERS CAN BE CLASSIFIED
DEPENDING ON THE
CHARACTERISTICS OF THEIR
OUTPUT
BRUSHLESS DC
AMPLIFIER IS
LINEAR AND USED
WITH A
BRUSHLESS
SERVO MOTOR
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MOTION CONTROL/SERVO
SYSTEMS
AMPLIFIERS CAN BE CLASSIFIED
DEPENDING ON THE
CHARACTERISTICS OF THEIR
OUTPUT
BRUSHLESS AC
AMPLIFIER IS
LINEAR AND USED
WITH A
BRUSHLESS
SERVO MOTOR
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MOTION CONTROL/SERVO
SYSTEMS
AMPLIFIERS CAN BE CLASSIFIED
DEPENDING ON THE
CHARACTERISTICS OF THEIR
OUTPUT
VECTOR CONTROL
AMPLIFER IS
LINEAR AND IS
CAPABLE OF
SERVO CONTROL
OF AN AC
INDUCTION TYPE
MOTOR
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MOTION CONTROL/SERVO
SYSTEMS
BRUSH-TYPE DC
MOTORS ARE
OLDEST AND
MOST USED IN
INDUSTRIAL
FEEDBACK
SERVOS WITH
THEIR TIME
PROVEN
TECHNOLOGY
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MOTION CONTROL/SERVO
SYSTEMS
STEPPING MOTORS ARE USED IN
AN “OPEN LOOP” AND
OPERATE AT HIGH TORQUE
AND LOW SPEED
A SPECIALIZED AC MOTOR RUNS
AN OPEN LOOP WHICH GIVES
NO FEEDBACK SO THE
CONTOLLER INSTRUCTS THE
ACTUATOR AND THEN DOES
NOTHING TO SEE IF THE JOB IS
DONE
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MOTION CONTROL/SERVO
SYSTEMS
BRUSHLESS MOTORS ALLOW LOWER
ROTOR INERTIA AND EFFICIENT
THERMAL DISSIPATION RESULTING
IN FASTER ACCELERATION
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MOTION CONTROL/SERVO
SYSTEMS
INDUCTION MOTORS NOW USE VECTOR
CONTROL TO IMPROVE THE USE OF
THESE MOTORS AND INCREASE THEIR
USE IN SPINDLE APPLICATIONS
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MOTION CONTROL/SERVO
SYSTEMS
FEEDBACK DEVICES CAN BE MOUNTED
ON THE MOTORS AND IN THE CONTROL
SYSTEM PROVIDES A NEGATIVE
SIGNAL/NEGATIVE FEEDBACK
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MOTION CONTROL/SERVO
SYSTEMS
FEEDBACK DEVICES INCLUDE
OPTICAL ENCODERS AND
RESOLVERS
TWO TYPES ARE
INCREMENTAL AND
ABSOLUTE EACH OF WHICH
IS HIGHLY ACCURATE AND
INCREMENTAL OPTICAL
ENCODERS ARE LOW COST
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MOTION CONTROL/SERVO
SYSTEMS
FEEDBACK CAN PROVIDE THE
SYSTEM WITH AN ERROR SIGNAL
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MOTION CONTROL/SERVO
SYSTEMS
FEEDBACK DEVICES
INCLUDE OPTICAL
ENCODERS AND
RESOLVERS
RESOLVERS USE A
POSITION TRANSDUCER
UTILIZING MAGNETIC
COUPLING FOR
ABSOLUTE SHAFT
POSITION
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MOTION CONTROL/SERVO
SYSTEMS
FEEDBACK DEVICES CAN BE
USED FOR SAFETY AND
STATUS MONITORING
MONITORING SYSTEMS
FEEDBACK INFORMATION
ABOUT ABNORMAL
CONDITIONS
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MOTION CONTROL/SERVO
SYSTEMS
ADJUSTABLE SPEED MOTORS AND DRIVES
AC MOTORS AND DRIVES
DC MOTORS AND DRIVES
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MOTION CONTROL/SERVO
SYSTEMS
ADJUSTABLE SPEED
MOTORS AND DRIVES
AC MOTORS AND
DRIVES ARE
KNOWN AS
“VOLTS PER
HERTZ DRIVES”
WHICH ARE OPEN
LOOP INDUCTION
MOTOR DRIVES
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MOTION CONTROL/SERVO
SYSTEMS
ADJUSTABLE SPEED MOTORS AND
DRIVES
AC MOTORS AND DRIVES HAVE A
NUMBER OF PROGRAMMABLE
FEATURES:
DISCRETE SPEED SELECTIONS
ACCELERATION AND DECELERATION
BOOST
VOLTS/HERTZ SETTING
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MOTION CONTROL/SERVO
SYSTEMS
ADJUSTABLE SPEED MOTORS AND DRIVES
DC MOTORS AND DRIVES ARE THE
LOWEST COST WITH THE BRUSH
MOTOR’S WEAR LIMITING ITS
USEFULNESS
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MOTION CONTROL/SERVO
SYSTEMS
ADJUSTABLE SPEED
MOTORS AND DRIVES
DC MOTORS AND
DRIVES ARE THE
LOWEST COST WITH
THE BRUSHLESS
MOTOR’S BEING
MORE EXPENSIVE
THAN THOSE WITH
BRUSHES
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MOTION CONTROL/SERVO
SYSTEMS
SELECTING AC OR
DC MOTORS OF
ADJUSTABLE
SPEEDS INVOLVES
LOAD
MOTOR LOADS ARE
GROUPED BY
TORQUE,
HORSEPOWER AND
SPEED
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MOTION CONTROL/SERVO
SYSTEMS
CONSTANT TORQUE
LOAD DEMANDS THE
LOAD IS CONSTANT AT
ALL SPEEDS WHICH
CHARACTERISTICALLY
IS NEEDED TO
OVERCOME FRICTION
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MOTION CONTROL/SERVO
SYSTEMS
CONSTANT HORSEPOWER IS
DEMANDED
WHEN THE INCREASE OF SPEED WILL
DECREASE THE TORQUE
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MOTION CONTROL/SERVO
SYSTEMS
A VARIABLE TORQUE
LOAD MUST SATISFY
THE MATHEMATICAL
EQUATION
TORQUE =
CONSTANT(SPEED)2
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MOTION CONTROL/SERVO
SYSTEMS
CLASSIFYING YOUR APPLICATION BY
ANSWERING THE FOLLOWING
QUESTION: WHAT TYPE OF
PROCESS IS THE MOTION BEING
APPLIED TO?
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MOTION CONTROL/SERVO
SYSTEMS
QUESTION: WHAT TYPE OF
PROCESS IS THE MOTION
BEING APPLIED TO?
WEB LINES, METAL
REMOVAL, ROBOTICS,
GENTRY, PACKAGING,
TRANSFER LINES,
AUTOMATED
STORAGE/RETRIVAL
SYSTEMS
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MOTION CONTROL/SERVO
SYSTEMS
FOLLOWING
CLASSIFICATION,
THE APPLICATION
PARAMETERS
MUST BE DEFINED
THIS WILL HELP
DETERMINE THE
MACHINE, MOTION
CONTROL,
ACTUATOR, AND
FEEDBACK DEVICE
REQUIREMENTS
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MOTION CONTROL/SERVO
SYSTEMS
QUESTIONS TO BE ANSWERED FOR
THESE APPLICATION PARAMETERS
INCLUDE HOW MUCH?, HOW FAST?,
AND HOW ACCURATE?
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MOTION CONTROL/SERVO
SYSTEMS
THESE QUESTIONS ARE
ANSWERED IN THE AREAS
OF MOTION PARAMETERS,
CONTINUOUS LOAD
REQUIREMENTS, MACHINE
CHARACTERISTICS,
COMMUNICATION
CHARACTERISTICS,
INPUT/OUTPUT
REQUIREMENTS AND
FEEDBACK
REQUIREMENTS
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MOTION CONTROL/SERVO
SYSTEMS
MOTION REQUIREMENTS MUST BE
UNDERSTOOD IN THE
FOLLOWING FOUR CATEGORIES
SIMPLE CONTROL
OF POSITION OR
VELOCITY OF
SINGLE OR NONSYNCHORONIZED
MULTIPLE AXES
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MOTION CONTROL/SERVO
SYSTEMS
MOTION REQUIREMENTS MUST BE UNDERSTOOD IN
THE FOLLOWING FOUR CATEGORIES
MOTION SYNCHRONIZED TO
EXTERNAL EVENTS
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MOTION CONTROL/SERVO
SYSTEMS
MOTION
REQUIREMENTS
MUST BE
UNDERSTOOD IN
THE FOLLOWING
FOUR CATEGORIES
SYNCHRONIZED
MULTI-AXIS
CONTROL
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MOTION CONTROL/SERVO
SYSTEMS
MOTION
REQUIREMENTS
MUST BE
UNDERSTOOD IN
THE FOLLOWING
FOUR CATEGORIES
COMPLEX MOTION
ALGORITHMS
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MOTION CONTROL/SERVO
SYSTEMS
THE PHYSICS OF MOTION
MOMENTS OF INERTIA: EVERY
MOVING BODY POSSESSES INERTIA
AROUND A PARTICULAR AXIS
CALCULATE THE MOMENT OF INERTIA FOR A
BOWLING BALL WITH A DIAMETER OF 25cm
AND A WEIGHT 4kg, THE MOMENT OF INERTIA
AROUND ITS CENTER IS: J=(2/5)Mr2 ;
J=(2/5)4kg(.125m) 2;J=.025kg(m) 2
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MOTION CONTROL/SERVO
SYSTEMS
THE PHYSICS OF MOTION
ANGULAR MOMENTUM
THE ANGULAR MOMENTUM OF A ROTATIONAL BODY IS
GIVEN BY THE RELATION ANGULAR MOMENTUM
EQUALS MOMENT OF INERTIA TIMES ANGULAR
(P=Jw). BODIES OR SYSTEMS IN ROTATIONAL
MOTION, UNLESS ACTED UPON BY AN EXTERNAL
FORCE, EXHIBIT CONSERVATION OF ANGULAR
MOMENTUM(Jw) IS ACONSTANT)
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MOTION CONTROL/SERVO
SYSTEMS
THE PHYSICS OF MOTION
ANGULAR ACCELERATION
ROTATING BODIES MAY UNDERGO
CHANGES IN ANGULAR VELOCITY
JUST AS BODIES IN TRANSLATION
UNDERGO CHANGES IN THEIR LINEAR
VELOCITY: A=(O1 – O2)/t
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MOTION CONTROL/SERVO
SYSTEMS
THE PHYSICS OF MOTION
TORQUE IS THE CAUSE OF ANGULAR
ACCELERATION, IT IS EQUAL TO THE
PRODUCT OF THE FORCE
PERPENDICULAR TO THE RADIUS OF
MOTION AND THE DISTANCE FROM
THE CENTER OF ROTATION TO THE
POINT WHERE THE FORCE IS
APPLIED: T = F•r
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MOTION CONTROL/SERVO
SYSTEMS
THE PHYSICS OF MOTION
POWER IS TRANSMITTED BY ROTATING
SHAFTS BY VIRTUE OF THE FACT
THAT THE TORQUE APPLIED
PRODUCES AN ANGULAR VELOCITY:
P = Tw
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MOTION CONTROL/SERVO
SYSTEMS
THE PHYSICS OF MOTION
COEFFICIENT OF FRICTION IS THE FRICTIONAL
FORCE BETWEEN TWO SURFACES, IT EQUALS
THE PRODUCT OF THE FORCE PRESSING THE
SURFACES TOGETHER TIMES THE
COEFFICIENT OF FRICTION: F = WK
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MOTION CONTROL/SERVO
SYSTEMS
DIFFERENTIATE CONTROLS OF
HYDRAULIC AND PNEUMATIC
CONTROLS
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