Peter Dirnberger, Stefan Fragner Nowadays, the market demands compact, stable, easy maintain-and customizable embedded systems. To meet these requirements, afast, simple and reliable implementation of control algorithms is crucial. This paper demonstrateshow model-based design with the help of Scilab/Xcosand X2C, developed by LCM,simplifiesand speedsup the development and implementation of controlalgorithms. As an example, acontrol schemefor a bearingless motoris presented.

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Model-based control development and automated code generation
Peter Dirnberger, Linz Center of Mechatronics GmbH
Scilab Conference 2019

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Content of the presentation
• Short introduction
• What is X2C
• Structure
• X2C Libraries
• X2C Communicator
• Building process
• Online Debugging and Tuning (X2C Scope)
• Example: Control of a bearingless motor with X2C
• What is a bearingless motor
• Position control
• Speed control
• Km transformation matrix
• Power fail
• Benefits of X2C

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Introduction
• Linz Center of Mechatronics GmbH (LCM)
• R & D service provider
• Transfers research results into industrial application
• Founded 2001
• 110 Employees
• 3 Business Areas
• Drives
• Electrical Drives
• Hydraulic Drives
• Mechanics & Control
• Sensors & Communication
• Peter Dirnberger
• I live in Linz, Austria
• I have studied Mechatronics at the Johannes Kepler University
• Since 2005 I have been working at LCM – Electrical Drives
Vienna
Linz
Salzburg
Munich
AUSTRIA
Praha
www.lcm.at

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Structure of a X2C control model
X2C-Hardware-Outports (OUT)X2C-Hardware-Inports (IN)
X2C-Blocks
X2C-Function-Blocks
Target
(ANSI C)
Model
Boot loader (optional)
PC
(Xcos)
X2C Communicator
Model
Frame program
Application
IN OUT

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Ready-made and tested blocks
X2C Libraries
General
Control
Math
MotorControl
BearinglessMotorControl
MotorSensorless
StateControl
X2C libraries of the free version Additional X2C libraries

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X2C Block
Select block implementation:
• Boolean
• 8 bit fixed point
• 16 bit fixed point
• 32 bit fixed point
• 32 bit floating point
• 64 bit floating point
Input/change of a control parameter by
• typing a value
• pressing the arrow buttons
• turning the mouse wheel
Parameters can also be
defined by variables.

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X2C Communicator
Setup communication via
• Serial
• CAN
• Ethernet

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Building Process
download to target
(X2C boot loader required)
create code (X2C.c/X2C.h)
compilation (with target IDE)

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Online parameter tuning
Tuning of a control parameter by
• typing a value
• pressing the arrow buttons
• turning the mouse wheel
• by a double click on the block in the Xcos model • by X2C Communicator GUI
In both cases the parameters can be determined online when the Communicator is connected to the target.

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Debugging – X2C Scope – a virtual oscilloscope
trigger modes
sampling time
The monitoring of
• block inputs
• block outputs
• global variables
• memory addresses
is possible
Gain and offset values
simplify interpretation, the
signal can be converted into
physical quantities

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Content of the presentation
• Short introduction
• What is X2C
• Structure
• X2C Libraries
• X2C Communicator
• Building process
• Online Debugging and Tuning (X2C Scope)
• Example: Control of a bearingless motor with X2C
• What is a bearingless motor
• Position control
• Speed control
• Km transformation matrix
• Power fail
• Benefits of X2C

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Bearingless motor
Drive
Radial bearing Axial bearing
Power
Electronics
Axial bearing
Radial bearing
Bearingless Motor
Power
Electronics
Backup bearing
• Magnetically supported drive
• Drive and suspension are decoupled
• Separate design/optimization of drive
and bearings is possible
• Mechanical and electrical hardware
demands are quite high
• “Bearingless” motor
• Compact system (mechanically and
electrically)
• Drive and suspension system are
coupled
• More complex control structure is
needed
Silber S.: „Beiträge zum lagerlosen Einphasenmotor“, Dissertation, Johannes Kepler University Linz, 2000

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Bearingless slice motor
Slice rotor = diameter of the rotor is large in comparison to its length
Advantage:
three of the six degrees of freedom can be stabilized passively by reluctance forces
• axial position
• two tilting directions
Only the radial position of the rotor must be controlled actively to levitate the rotor
Barletta N., Schöb R.: “Design of a bearingless blood pump”, Proc. 3rd Int. Symp. Magnetic Suspension Technology (ISMST), pp 265-274, 1995

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Bearingless slice motor
• Axial position - stabilized passively
Gruber W., Amrhein W., Haslmayr M.: “Bearingless segment motor with five stator elements - design and optimization”, IEEE Trans. Industry Applications, vol. 45, 2009
Gruber W., Amrhein W., Stallinger T.: "Bearingless segment motor with buried magnets", JSME Journal of System Design and Dynamics, vol. 3, no. 5, pp. 704-716, 2009
• Radial position – must be controlled actively
• Determine radial positon via position sensors
• With the five stator coils, forces are applied to center the rotor in the middle
• Torque – in addition a conventional rotating field is generated with the five stator coils
(like a standard PMSM)
• Two tilting directions - stabilized passively
x
y

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Bearingless slice motor
Gruber W., Silber S.: “20 Years Bearingless Slice Motor - its Developments and Applications”, ISMB15, 2016
Most common
design variants

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X2C control scheme for bearingless motor control in Xcos
Position controlx
y

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X2C control scheme for bearingless motor control in Xcos
Speed control
Rotor angle and speed determination

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X2C control scheme for bearingless motor control in Xcos
Km transformation matrix
0 180 360
-20
0
20
0 180 360
-20
0
20
0 180 360
-500
0
500
0 180 360
-20
0
20
0 180 360
-20
0
20
0 180 360
-500
0
500
0 180 360
-20
0
20
0 180 360
-20
0
20
0 180 360
-500
0
500
0 180 360
-20
0
20
0 180 360
-20
0
20
0 180 360
-500
0
500
0 180 360
-20
0
20
0 180 360
-20
0
20
0 180 360
-500
0
500
φ[°]
Fx [A /N]turns Fy [A /N]turns T turns[A /Nm]
i1i5i4i3i2
Calculate target values for the five coils currents from the demanded force and torque values
Silber S., Amrhein W.: "Power optimal current control scheme for bearingless PM motors", Proc. 7th International Symp. on Magnetic Bearings (ISMB), pp. 401-406, 2000
• The Km matrix results from inverting the
Tm matrix.
• To determine the Tm matrix, the rotor is
centered and each phase is energized
one after the other. The phase-related
resulting forces acting on the rotor in x-
and y-direction as well as the torque are
determined as a function of the rotor
angular position and arranged in matrix
form as Tm.
x
y

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X2C control scheme for bearingless motor control in Xcos
Current control

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X2C control scheme for bearingless motor control in Xcos
Power failure - what now?
In order to keep the levitation of the rotor stable, energy is required.
 Use of the energy stored in the rotation of the rotor

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Content of the presentation
• Short introduction
• What is X2C
• Structure
• X2C Libraries
• X2C Communicator
• Building process
• Online Debugging and Tuning (X2C Scope)
• Example: Control of a bearingless motor with X2C
• What is a bearingless motor
• Position control
• Speed control
• Km transformation matrix
• Power fail
• Benefits of X2C

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time
Benefits of using X2C
Conclusion
unit test
design
coding
X2C
Model
Block
time
specification acceptance test
integration test

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Benefits of using X2C
Conclusion
• Graphical design of the control scheme with pre-designed and pre-tested blocks
• X2C Scope - a virtual oscilloscope
intuitive tool for online data visualization and debugging
• Instant online parameter update from Xcos to target
• Simulation with “target code” in Xcos
• Automated documentation generation for projects
• Comprehensive libraries with pre-tested blocks
• Independent of target
• Multiple fixed and floating point implementations
• Inbuilt parameter conversion (e.g. continuous time to discrete time)
• Generated code is easily readable

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Thank you
This work has been supported by the COMET-K2 Center of the Linz Center of Mechatronics (LCM) funded
by the Austrian federal government and the federal state of Upper Austria
https://x2c.lcm.at/
x2c@lcm.at