Transcript Tutorial on Servo

Servo Drives
State of the Art
and Modern Developments
Prof. Dr.-Ing. J. M. Pacas, Institut für Leistungselektronik und Elektrische Antriebe,
Univer sität Siegen
Prof. Dr.-Ing. R. M. Kennel, Lehrstuhl für elektr ische Maschinen und Antriebe,
Bergische Un iversität Wuppertal
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)
Prof. Dr. -Ing. J. M. Pacas, University of Siegen
Prof. Dr. -Ing. R. M. Kennel, Wuppertal University
Page 1
Typical Machine Tool
feed drives
control the position
between working piece
and working tool
main drives
provide
processing power
Prof. Dr. -Ing. J. M. Pacas, University of Siegen
Prof. Dr. -Ing. R. M. Kennel, Wuppertal University
Page 2
Parallel Kinematics
TriCenter DMT 100
(Deckel Maho)
Prof. Dr. -Ing. J. M. Pacas, University of Siegen
Prof. Dr. -Ing. R. M. Kennel, Wuppertal University
Page 3
Characteristics of Servo Drives
feed
high maximum torque
high efficiency
constant maximum torque
small size
speed range < 10.000 rpm
drives
axis
smooth
operation
at low speeds
Spindle
rated power < 20 kW
high rated/continuous torque
constant maximum power
drives
main
4 quadrant
operation
speed range < 20.000 rpm
rated power < 100 kW
Prof. Dr. -Ing. J. M. Pacas, University of Siegen
Prof. Dr. -Ing. R. M. Kennel, Wuppertal University
Page 4
Hystory of Motor Types in Servo Drives
ASM
asynchronous
motor
ASM
?
DC
SM
synchronous
motor
SM
?
SM
EC
brushless
DC
1970 ff.
1980 ff.
1990 ff.
Prof. Dr. -Ing. J. M. Pacas, University of Siegen
Prof. Dr. -Ing. R. M. Kennel, Wuppertal University
Page 5
State of the Art: AC Servos
High Speed Spindle
(Siemens)
High Torque Motor
(Baumüller)
DSD Servo
(Baumüller)
Spindle Motor
(Franz Kessler)
Prof. Dr. -Ing. J. M. Pacas, University of Siegen
Prof. Dr. -Ing. R. M. Kennel, Wuppertal University
Page 6
Inverters for Servo Drive Applications
Prof. Dr. -Ing. J. M. Pacas, University of Siegen
Prof. Dr. -Ing. R. M. Kennel, Wuppertal University
Page 7
Encoders
Advantages
• low cost
• high accuracy
(e. g. by gear ratio)
Disadvantages
• elastic effects
and back lash
source : ERN-Geber, Heidenhain
Prof. Dr. -Ing. J. M. Pacas, University of Siegen
Prof. Dr. -Ing. R. M. Kennel, Wuppertal University
Page 8
Encoder Technologies
technology
magnetic
magnetisch
magnetic
optisch
optical
optical
kapazitive
capacitive
capacitive
Meßbereich
measuring
area
Robustheit
robustness
measuring area
Auflösung
resolution
resolution
robustness
Massenproduktion
mass production
mass production
Resolver:
circular
low
good
bad
tooth wheel:
point
(multipole resolver: 20
Bit)
problematic
very good
(sensitive to
temperature
and shock)
(photographic
production)
point
high
(CCD: > 30 Bit)
Too less experience to make knowledge-based statements.
circular
high
good
Prof. Dr. -Ing. J. M. Pacas, University of Siegen
Prof. Dr. -Ing. R. M. Kennel, Wuppertal University
good
Page 9
AC Servo Drive Control
speed
M-Regler
controller
current
Stromcontrollers
Regler
i*q
n*
-
*
field weakening
e
i*d
-
Feldschwächung
Feld-Regler
field controller
e
-j


M
3~
j
-
Mamachine
schinenmodell
model
for asynchronous
machines
i
Encoder
e-j
u
for synchronous
machines
Prof. Dr. -Ing. J. M. Pacas, University of Siegen
Prof. Dr. -Ing. R. M. Kennel, Wuppertal University
Page 10
Motion Control (e. g. Electronic Gear)
Virtual
Virtueller
Master
master
Synchronisierte
Synchronized
Kommunikation
communication
Hauptantrieb
main drive
Prof. Dr. -Ing. J. M. Pacas, University of Siegen
Prof. Dr. -Ing. R. M. Kennel, Wuppertal University
Page 11
Sensorless Control Categories
models based on anisotropies
fundamental models
emf-model,
Observer
flux
modulation
...
dq-inductance
rotor slotting
effect
main field
saturation
Prof. Dr. -Ing. J. M. Pacas, University of Siegen
Prof. Dr. -Ing. R. M. Kennel, Wuppertal University
...
Page 12
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
Prof. Dr. -Ing. J. M. Pacas, University of Siegen
Prof. Dr. -Ing. R. M. Kennel, Wuppertal University
Page 13
Drives with Diagnostic Features
Prof. Dr. -Ing. J. M. Pacas, University of Siegen
Prof. Dr. -Ing. R. M. Kennel, Wuppertal University
Page 14
Distributed/Decentralized Control
Prof. Dr. -Ing. J. M. Pacas, University of Siegen
Prof. Dr. -Ing. R. M. Kennel, Wuppertal University
Page 15
SERCOS interface
MDT
AT 1
MST
AT 2
AT m
AT M
MST
t1.1
t1.2
t1.m
t1.M
t2
tScyc
• t1.x
• t2
• tScyc
AT transmission starting time
MDT transmission starting time
SERCOS cycle time
Prof. Dr. -Ing. J. M. Pacas, University of Siegen
Prof. Dr. -Ing. R. M. Kennel, Wuppertal University
Page 16
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
Prof. Dr. -Ing. J. M. Pacas, University of Siegen
Prof. Dr. -Ing. R. M. Kennel, Wuppertal University
Page 17