Tutorial on Servodrives

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(No Transcript)
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Outline

• General Requirements, State of the Art,
  Structure and Components of Servo Drives
• Drive Control with Position/Speed Encoder
• Motion Control
• Drive Control without Position/Speed Encoder
• Data Exchange (Communication)

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Typical Machine Tool
feed drives control the position between working
piece and working tool main drives provide proces
sing power
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Parallel Kinematics
TriCenter DMT 100 (Deckel Maho)
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Characteristics of Servo Drives
feed drives axis
high efficiency small size smooth operation at
low speeds 4 quadrant operation
high maximum torque constant maximum
torque speed range lt 10.000 rpm rated power lt
20 kW
Spindle drives main
high rated/continuous torque constant maximum
power speed range lt 20.000 rpm rated power lt
100 kW
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Hystory of Motor Types in Servo Drives
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State of the Art AC Servos
High Speed Spindle (Siemens)
DSD Servo (Baumüller)
High Torque Motor (Baumüller)
Spindle Motor (Franz Kessler)
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Inverters for Servo Drive Applications
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Encoders

• Advantages
• low cost
• high accuracy
• (e. g. by gear ratio)

• Disadvantages
• elastic effects
• and back lash

source ERN-Geber, Heidenhain
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Encoder Technologies
technology
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AC Servo Drive Control
speed controller
current controllers
field weakening
field controller
machine model
for asynchronous machines
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Motion Control (e. g. Electronic Gear)
Synchronized communication
Virtual master
main drive
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Sensorless Control Categories
models based on anisotropies
fundamental models
emf-model, Observer
dq-inductance
main field saturation
...
rotor slotting effect
flux modulation
...
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Industrial Drives with Sensorless Control
since several years / decades sensorless control
is investigated and published on conferences and
magazines
- acceptance in industry, however, is rather low
Why ?
new ideas and concepts are interesting for
industry, only if they do not result in higher
cost or higher effort!!!
What does that mean for industrial drives with
sensorless control ?
? no additional or more powerful processors /
controllers
? no additional hardware or additional sensors
(e. g. voltage sensors)
? no increased installation effort with respect
to parameter adjustments
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Drives with Diagnostic Features
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Distributed/Decentralized Control
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SERCOS interface
MDT
AT
MST
AT
AT
AT
MST
M
m
1
2
t
1.1
t
1.2
t
1.m
t
1.M
t
2
t
Scyc

• t1.x AT transmission starting time
• t2 MDT transmission starting time
• tScyc SERCOS cycle time

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Future Developments

• Motors (Actors)
• synchronous motors with surface mounted permanent
  magnets as a standard
• - different solutions in special applications
  only (for cost reasons)

• Signal Processing
• further developments on speed/position encoders
  to be expected
• sensorless/encoderless control only, if
• ? no additional hardware effort (processors
  and/or sensors) ? no parameter dependencies
  during operation

• Data Exchange/Communication
• synchronized communication systems are demanded
• for multi axis servo drive systems for high
  requirements