1. More efficient machines
through model based
design
Wim Symens
Seminar « Produceer met
minder energie »
November 8, 2011, Ghent

2. Flanders’ Mechatronics Technology Centre
+ FMTC vzw:
 Non-profit organization
 Started in 2003
 In 2010: +3.7 M€ income with +30 people
 Membership for Flemish companies
 Business outside Flanders as well
+ Our market: Machine building and
mechatronic component industry
+ Our competence: Mechatronics
= integration of electronics and software in
mechanical systems
And this way improve the performance/cost ratio of
machines
+ Our business: Application oriented research
projects
© FMTC vzw 2011 • p2

3. Outline
+ Motivation and needs
+ Model based design approach
+ Example: badminton robot
+ Do it all on your own?
+ Summary and conclusions
© FMTC vzw 2011 • p3

4. Motivation and needs
Scarcity of energy
+ Societal awareness
 Consider energetic impact of the things you are doing
 Be ‘green’
 Increasingly stringent legislation
+ Economic angle
 Increasing prices for energy
 Contribution of cost of consumed energy during use phase of machine in
Total Cost of Ownership increases
+ As a results
 Need to reduce energetic footprint machines
 Energy efficiency (during use phase) becomes a differentiating
performance characteristic
© FMTC vzw 2011 • p4

5. Motivation and needs
Energy optimization in industry can result in
gigantic savings
1% saving
Energy Consumption Flanders 2007
Other = 2,4 PJ/a
Industry = 677 GWh/a
38,4% = 100,7 million
53%
€/a
= 35 kton
CO2/a
Households
Industry
Agriculture
Transport Chemistry
Trade & Services 19%
61,6%
3%
Totaal = 1197 PJ
(1015J) 9% 16%
Source: MIRA
© FMTC vzw 2011 • p5

6. Motivation and needs
Reduce energy consumption during the use phase
+ In general
 Avoid useless energy consumption!
 Reduce stand-by losses
 Use energy efficient components, e.g. energy-efficient motors
 If the process generates energy, recuperate it or reuse it
 Braking energy
 Waste heat
 (Use efficiently generated energy)
+ Applied to (complex) production machines
 Component level
 Use energy efficient components
 However: might cause performance changes, e.g. electrical motor for dynamic
applications
 System level
 Allows taking into account interaction between components in machine
 Most opportunities, but less straightforward
© FMTC vzw 2011 • p6

7. Outline
+ Motivation and needs
+ Model based design approach
+ Example: badminton robot
+ Do it all on your own?
+ Summary and conclusions
© FMTC vzw 2011 • p7

8. Model based design approach
Model based analysis and design
+ Systematic approach necessary to realize optimized design
+ Model based approach offers designers the opportunity to
quickly evaluate the impact of design changes
 Describe energetic behavior components mathematically
 Combine components
 Simulate machine behavior
+ Needs to be embedded in design tools
for easy use
 Various (CAE) softwares are already used
during machine design, e.g for
 Strength and stiffness calculations (FE)
 Collision avoidance
 (Extend) tools with capabilities for energetic analysis
 Simulate energy flows
 Identify the (location of) energy losses
 Evaluate alternatives
© FMTC vzw 2011 • p8

9. Model based design approach
Towards an integrated design environment
+ Describe energetic behavior of components, next to functional
behavior
 Energy and power next to forces, displacements, etc.
+ Softwares exist that provide this functionality
 E.g. LMS.Amesim, Matlab/Simscape software
+ Efficient and effective visualization of models and results is
crucial
© FMTC vzw 2011 • p9

10. Model based design approach
Typically iterative process
Design for energy efficiency
+ Unrealistic and unnecessary to Identification of most
relevant phenomena
model and analyze the whole
the machine
Modeling and analysis
+ Understand where energy is of most relevant
components
used in the machine
 Existing machine
Identification of losses
 Can do measurements
 New machine
 Previous experience
Improved design
 Stepped approach: from rough
analysis to detailed analysis
 Analyze various scenarios /
Energy consumption in
concepts in simulation operation
© FMTC vzw 2011 • p10

11. Outline
+ Motivation and needs
+ Model based design approach
+ Example: badminton robot
+ Do it all on your own?
+ Summary and conclusions
© FMTC vzw 2011 • p11

12. Example: badminton robot
Demonstration application
+ In 2009 FMTC decided to build machine for demonstration purposes
+ Machine should include fast dynamics, wireless sensors and interaction
between different systems
+ A badminton playing robot was selected
+ First version realized following a ‘standard’
engineering design approach using
off-the-shelf components
 Design based on maximal forces / stresses
 Energy considerations not taken into account
 Linear motor / rotary motors / cameras
 Time optimal controller implementation
+ First version (2009) has limited work space
+ Currently a second version with full work space is being designed
© FMTC vzw 2011 • p12

13. Example: badminton robot
Badminton robot: system
+ Developed by FMTC in 2009 – see movie
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14. Example: badminton robot
First attempt to reduce energy consumption
+ Engineering reasoning of main losses
 Robot is mainly accelerating and decelerating masses
 Deceleration energy is ‘burned’ in braking resistor
+ Reduce energy consumption?
 Recuperate braking energy and reuse this energy
+ Capacitors added to system
+ Very little reduction in energy consumption (under 5%)!
+ Why is this so?
+ More systematic analysis needed!
© FMTC vzw 2011 • p14

15. Example: badminton robot
Goal of the analysis
+ Analyze energy
consumption
+ Identify losses
+ Reduce losses
Rot. Motor M2
+ How?
Linear Motor
 Modeling of drive components:
 Linear Motor
 2 Rotary Motors (M1,2)
 Controller
 Mechanics
Rot. Motor M1  Analyze loss during
operational conditions
 Improve where possible
© FMTC vzw 2011 • p15

16. Example: badminton robot
First step: focus on linear motor
+ Analysis for specific situation: robot is on left position of the
linear motor guide and has to move to the right position
© FMTC vzw 2011 • p16

17. Example: badminton robot
Badminton robot: energetic model made
Trajectory Position
Target generator Controller Plant
position
v/m/s Trajectory generator / PTOS parameters
Amax * α
• Amax : maximal acceleration, linked to the
actuator limitations.
Amax
Amax • α: acceleration discount, allows the
limitation of the deceleration torque
© FMTC vzw 2011 • p17

18. Example: badminton robot
Badminton robot: parameter tuning
+ From catalogues
 e.g. motor
parameters
+ Experimentally
 e.g. friction
parameters
(no information
available!)
© FMTC vzw 2011 • p18

19. Example: badminton robot
Badminton robot: energy analysis (I)
Energy flow without additionnal capacitance - Simulation + 1: start
+ 2: overshoot
+ 3: constant
velocity
+ 4: stop
Region Region Region Region
   
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20. Example: badminton robot
Badminton robot: energy analysis (II)
+ Energy flow analysis results
 Main loss can be attributed to copper losses
and friction losses
+ Solution?
 Reduce friction losses
 Other guides? Is being further investigated
 Reduce copper loss
 ~I2; I~F; F~acceleration => reduce
acceleration!
+ Current implementation
 Time optimal
 Is it relevant to exploit spare time to improve
efficiency?
+ Ad-hoc analysis
 Vary parameters of PTOS algorithm
 Amax: maximum acceleration
 α: limits the deceleration torque
© FMTC vzw 2011 • p20

21. Example: badminton robot
Badminton robot: potential of controller
improvement
[s]
+ Simulation
 47% more energy needed for only 14% efficiency improvement
+ Experiment
 55 % more energy needed for only 10% efficiency improvement
© FMTC vzw 2011 • p21

22. Outline
+ Motivation and needs
+ Model based design approach
+ Example: badminton robot
+ Do it all on your own?
+ Summary and conclusions
© FMTC vzw 2011 • p22

23. Do it all on your own?
How to obtain models?
+ Available libraries
+ Make them yourself
 Measurements
 Analytically
+ Ask them from
third parties
 Suppliers!
 Virtual Components!
© FMTC vzw 2011 • p23

24. Do it all on your own?
Virtual components
+ Co- modeling approach
offers formalized framework
for interacting with suppliers
+ Various formats information possible
 Formula’s with parameters
 Look-up tables
 Encrypted models
+ Encoding of information might be needed
 Functionality to be provided by CAE producer
+ Opportunity for supplier to show their products are most
efficient
+ Also stimulates interaction with R&D institutions
+ Similar developments in other sectors, e.g. automotive
© FMTC vzw 2011 • p24

25. Do it all on your own?
Example: motor models hitting
mechanism badminton robot
+ Initially motor-reductor selected
based on max. torque and speed
+ Evaluated different alternatives
experimentally (Maxwell, Faul-
haber, Smartmotor)
 Very low overall efficiency
 Initial selection was not most
efficient (+/- 5% increase of
efficiency possible)
+ Discussion with suppliers on-
going to provide information on
energy consumption motor-
reductor combination using
Virtual Component concept
 Should allow calculation application specific energy consumption
© FMTC vzw 2011 • p25

26. Outline
+ Motivation and needs
+ Model based design approach
+ Example: badminton robot
+ Do it all on your own?
+ Summary and conclusions
© FMTC vzw 2011 • p26

27. Summary and conclusion
More efficient machines through model based
design
+ Motivation: Energy reduction for environmental and economic reasons
+ Approach
 Take energy consumption into account on system level
 Follow mechatronic model based approach
 Interact with suppliers
+ Application on badminton robot
 Allowed analyzing the energy ‘sinks’
 Copper losses!
 Friction losses!
 (Ad-hoc) Energy-performance trade-off analysis
 Showed potential of tuning PTOS controller
+ Further actions
 Extend analysis capabilities, e.g. energy flow analysis dash-board instead of
bars/piecharts
© FMTC vzw 2011 • p27

28. Summary and conclusion
Energy Flow Visualization
3~
Electrical En. waste
Mechanical En. waste
Electrical En. Storage
Mechanical En. Storage
Electrical useful Energy
Mechanical useful Energy
© FMTC vzw 2011 • p28

29. Acknowledgement
+ The research leading to these results has received funding from the European
Union Seventh Framework Program (FP7/2007-2013) under grant agreement
n°247982– ESTOMAD
+ See www.estomad.org for more info
© FMTC vzw 2011 • p29

30. Questions
© FMTC vzw 2011 • p30