- Email: [email protected]
Components for Simulation of piezoelectrically actuated Systems with SyMSpace
8th IFAC Symposium on Mechatronic Systems 8th IFACAustria, Symposium Systems Vienna, Sept. on 4-6,Mechatronic 2019 8th IFACAustria, Symposium Systems online at www.sciencedirect.com Available Vienna, Sept. on 4-6,Mechatronic 2019 8th IFACAustria, Symposium Systems Vienna, Sept. on 4-6,Mechatronic 2019 Vienna, Austria, Sept. 4-6, 2019
ScienceDirect
IFAC PapersOnLine 52-15 (2019) 259–264
Components for Simulation of Components for Simulation of Components for Simulation of with piezoelectrically actuated Systems Components for Simulation of with piezoelectrically actuated Systems piezoelectrically actuated Systems SyMSpace piezoelectrically actuated Systems with with SyMSpace SyMSpace SyMSpace Daniel Reischl ∗ Martin Meindlhumer ∗∗ Martin Trinkl ∗∗∗
∗ ∗∗ ∗∗∗ Reischl Meindlhumer Martin ∗ ∗∗ ∗∗∗∗ ∗ Martin ∗∗ Silber ∗∗∗ Reischl Martin Meindlhumer Martin†† Trinkl Trinkl ∗∗∗ Astrid Pechstein ∗∗∗∗ Siegfried ∗ ∗∗ Astrid Martin Pechstein ∗∗∗∗ Siegfried Silber Reischl Meindlhumer Martin†† Trinkl ∗∗∗ ∗∗∗∗ Astrid Pechstein Siegfried Silber Astrid Pechstein ∗∗∗∗ Siegfried Silber † ∗ ∗ Linz Center of Mechatronics GmbH, Linz, Austria (e-mail: Linz Center of Mechatronics GmbH, Linz, Austria (e-mail: ∗ ∗ [email protected]) GmbH, Linz, Austria (e-mail: ∗ Linz Center of Mechatronics [email protected]) ∗∗ Center of Mechatronics Linz GmbH, Linz, Austria (e-mail: [email protected]) University, Linz, Austria (e-mail: ∗∗ Johannes Kepler Kepler University, Linz, Austria (e-mail: ∗∗ [email protected]) ∗∗ Johannes Johannes Kepler University, Linz, Austria (e-mail: [email protected]) ∗∗ ∗∗∗ Johannes [email protected]) Kepler University, Linz,Linz, Austria (e-mail: Mechatronics GmbH, Austria (e-mail: [email protected]) ∗∗∗ Linz Center of Linz Center of Mechatronics GmbH, Linz, Austria (e-mail: ∗∗∗ [email protected]) ∗∗∗ [email protected]) Linz Center of Mechatronics GmbH, Linz, Austria (e-mail: ∗∗∗ [email protected]) ∗∗∗∗ Center of Mechatronics Linz GmbH, Linz, Austria (e-mail: [email protected]) University, Linz, Austria (e-mail: ∗∗∗∗ Johannes Kepler University, Linz, Austria (e-mail: ∗∗∗∗ [email protected]) ∗∗∗∗ Johannes Kepler [email protected]) Johannes Kepler University, Linz, Austria (e-mail: ∗∗∗∗ [email protected]) † Johannes Kepler University, Linz, Austria (e-mail: GmbH, Linz, Austria (e-mail: [email protected]) † Linz Center of Mechatronics Linz Center of Mechatronics GmbH, Linz, Austria (e-mail: † [email protected]) † [email protected]) Linz Center of Mechatronics GmbH, Linz, Austria (e-mail: † [email protected]) Linz Center of Mechatronics GmbH, Linz, Austria (e-mail: [email protected]) [email protected]) Abstract: The concept of automating the computation steps in a design process along different Abstract: The of automating the steps aa design process different Abstract: tools The concept concept the computation computation steps in in design process along along different simulation leads toof aautomating more efficient use of knowledge and computational resources. In simulation tools leads toof aautomating more efficient use of knowledge and computational resources. In Abstract: The concept the computation steps in a design process along different this paper the software tool SyMSpace, which realizes this automatization, and the available simulation tools leads to a more efficient use of knowledge and computational resources. In this paper the software tool SyMSpace, which realizes this automatization, and resources. the available simulation tools leads to a more efficient use of knowledge and computational In components concerning the simulation of which piezoelectrically actuated systems isand presented. this paper the software tool SyMSpace, realizes this automatization, the available components concerning the simulation of which piezoelectrically actuated systems isand presented. this paper the software tool SyMSpace, realizes this automatization, the available The finite element modelthe of simulation a circular piezoelectric patch on a rectangular aluminium substrate components concerning of piezoelectrically actuated systems is presented. The element model of aa circular piezoelectric patch on aa rectangular aluminium substrate components concerning the ofaspiezoelectrically actuated systems is presented. The finite finite modelelements of simulation circular piezoelectric patch on rectangular aluminium substrate using novelelement mixed finite is used an example to show how to create a well-documented using novelelement mixed finite elements is used as an example to show how to create a well-documented The finite model of a circular piezoelectric patch on a rectangular aluminium substrate and easy-to-use component. Tangential displacements and normal normal stresses (TDNNS) are using novel mixed finite elements is used as an example to show how to create a well-documented and easy-to-use component. Tangential displacements and normal normal stresses (TDNNS) are using novel mixed finite elements is used as an example to show how to create a well-documented used as mechanical degrees ofTangential freedom and the finite elements are readily available in open source and easy-to-use component. displacements and normal normal stresses (TDNNS) are used as degrees freedom the are open and easy-to-use displacements and normal normalavailable stresses in (TDNNS) are used as mechanical mechanical degrees of ofTangential freedom and and the finite finite elements elements are readily readily available in open source source software packagecomponent. Netgen/NGSolve. software package Netgen/NGSolve. used as mechanical degrees of freedom theoffinite elements are readily open source software package Netgen/NGSolve. In order to simplify the installation andand usage specialized (open source)available software in tools and help In order to simplify the installation and usage of specialized (open source) software tools and help software package Netgen/NGSolve. to reproduce results in installation scientific publications, concept(open of (docker) is integrated In order to simplify and usage ofthe specialized source)containers software tools and help to reproduce resultsthe in installation scientific publications, concept(open of (docker) is integrated In order to simplify the and usage ofthe specialized source)containers software tools and help in SyMSpace. to reproduce results in scientific publications, the concept of (docker) containers is integrated in to reproduce results in scientific publications, the concept of (docker) containers is integrated in SyMSpace. SyMSpace. © 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. in SyMSpace. Keywords: System Design and Integration, Software Tools, Smart Structures, Smart Keywords: Design and Software Tools, Smart Structures, Smart Keywords: System System and Integration, Integration, Actuators, Motion Design and Vibration Control Software Tools, Smart Structures, Smart Actuators, Motion and Vibration Control Keywords: System and Integration, Actuators, Motion Design and Vibration Control Software Tools, Smart Structures, Smart Actuators, Motion and Vibration Control 1. INTRODUCTION INTRODUCTION As an an example example for for aa mechatronic mechatronic system, system, which which has has to to 1. As 1. INTRODUCTION As an example for a mechatronic system,mechanical which hasand to be modeled in at least 2 domains, namely be in atfor least 2 domains, namely mechanical and 1. INTRODUCTION As modeled an example a mechatronic system, which to be modeled in at least 2 domains, and electrical, piezoelectric actuatornamely is usedmechanical in this has paper. electrical, aa in piezoelectric actuator is used in this paper. be modeled at least 2 domains, namely mechanical and electrical, a piezoelectric actuator is used in this paper. In SyMSpace several predefined piezoelectrically actuated On the the one one hand hand mechatronic mechatronic systems systems are are getting getting more more In SyMSpace several predefined piezoelectrically actuated electrical, piezoelectric actuator is used components in this paper. On In SyMSpace several available predefined actuated systems area already already aspiezoelectrically so-called in On the one hand mechatronic systems on arethe getting more and more complex while simultaneously other hand systems are available as so-called components in In SyMSpace several predefined piezoelectrically actuated and more complex while simultaneously on the other hand systems are already available as so-called components in On the one hand mechatronic systems are getting more order to help the design engineer to set up the overall and more complex while simultaneously on the other hand the need need for for optimization optimization of of the the overall overall system system is is required. required. order to are helpalready the design engineer to set components up the overall systems available as so-called in the toAhelp the design engineer to set and up their the overall andorder moreto complex while simultaneously on the is other hand order system. collection of these these components usage the need for optimization of the overall system required. In address this problem, it is necessary to reduce system. A collection of components and usage order to help the design engineer to set up their the overall In order to address this problem, it is necessary to reduce system. A collection of these components and their usage the need for optimization of the overall system is required. is presented in Section 3. In to address this design problem, it is necessary reduce is theorder complexity for the the engineer as far far as astopossible possible presented in Section system. A collection of 3. these components and their usage the complexity for design engineer as is presented in Section 3. In order to address this problem, it is necessary reduce the complexity for the design engineer as models far astopossible while ensuring, that underlying simulation are still For universities and research departments knowledge knowledge manmanis presented in Section 3. while ensuring, that underlying simulation models are still the complexity for the design engineer as models far as possible universities and research departments while ensuring, that underlying simulation are still For valid and interaction between submodels is represented For universities and research departments knowledge management is essential to make sure, that models and tools valid and interaction between simulation submodels models is represented while ensuring, that underlying are still agement is essential to makedepartments sure, that models and mantools For universities andusable research knowledge valid and The interaction between submodels is significantly represented correctly. relevance of this this approach approach rises agement is essential to make sure, that projects models and tools are available and for follow-up and colcorrectly. The relevance of rises significantly valid and interaction between submodels is significantly represented available and usable for sure, follow-up projects andtools colagement is these essential to make thatpublically models and correctly. relevance of this approach as soon asThe multiple physical domains arerises involved as e.g. e.g. are are available andmodels usable for tools follow-up projects and colleagues. If and are available as soon as multiple physical domains are involved as correctly. relevance this approach significantly If these and are publically available areis aavailable andmodels usable for tools follow-up projects and colas soon asThe multiple physical domains arerises involved as e.g. leagues. electrical, mechanical orofthermal. thermal. leagues. If these models and tools are publically available it contribution to ’reproducable research’, as motivated motivated electrical, or as soon asmechanical multiple physical domains are involved as e.g. it is a contribution to ’reproducable research’, as leagues. If these models and tools are publically available electrical, mechanical or thermal. is abycontribution ’reproducable e.g. Fomel and and to Claerbout (2009).research’, as motivated In many mechanical cases it it is is or sufficient to use use the the results results of of aa it electrical, thermal.to e.g. Fomel Claerbout (2009). it is aby contribution to ’reproducable research’, as motivated In many cases sufficient e.g. by Fomel and Claerbout (2009). In many cases is sufficient use to thetheresults of a In simulation in the theitfirst first domain as astoinput input simulation Section 4 it is therefore presented how to to include include aa e.g. by Fomel and Claerbout (2009). simulation in domain to the simulation In amany cases is sufficient use thetheresults of of a In Section 4 it is therefore presented how simulation in domain. theitfirst domain asto input to simulation in second However the manual transfer In Section 4 it is therefore presented how to include mechanical simulation model of a new piezoelectrically in a second Howeveras the manual transfer of mechanical simulation model of a new piezoelectricallya simulation in domain. the domain input to the simulation In Sectionsystem 4simulation it isastherefore to include in adata second domain. Howevertool the transfer of mechanical the from onefirst simulation tomanual the next is errorerrormodelpresented ofcomponent. a newhow piezoelectrically actuated additional During thisa the data from one simulation tool to the next is in adata second domain. Howeveriftool thetomanual transfer of actuated system as additional component. During this mechanical simulation model of a new piezoelectrically the from one simulation the next is errorprone and may be exhausting done multiple times like actuated system as additional component. During this process, the the developer developer is is enforced enforced to to use use existing existing interfaces interfaces prone andfrom may one be exhausting if done times like process, the data simulation to multiple the 2next is erroractuated system as additional During this prone and may be exhausting during an optimization optimization process.iftool In Section thetimes software done multiple like process, the developer is enforcedcomponent. to use existing interfaces and document the model. during an process. In Section 2 the software prone and may be exhausting if In done multiple like and document the model. process, the developer is enforced to use existing interfaces during an optimization process. Section 2 thetimes software environment SyMSpace is presented which automates this environment SyMSpace process. is presented which automates this and document the model. during anfrom optimization In Section 2 the engineer software environment SyMSpace is presented which automates this and document the model. transfer one tool tool to to the next. next. The design design transfer from one the The engineer environment SyMSpace is presented which automates this transfer from one tool the to the next. The design engineer does not need to learn usage of the different tools but does not from need one to learn the usage of the different tools but transfer tool to the next. The design engineer does not need toon learn the usage can concentrate the design of the overall system. of the different tools but can the the design of of the overall system. doesconcentrate not need toon learn usage different tools but can concentrate on the design of thethe overall system. can concentrate on the design of the overall system. 2405-8963 © 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
Daniel Daniel Daniel
Copyright © 2019 IFAC 728 Peer review©under of International Federation of Automatic Copyright 2019 responsibility IFAC 728Control. Copyright © 2019 IFAC 728 10.1016/j.ifacol.2019.11.684 Copyright © 2019 IFAC 728
2019 IFAC MECHATRONICS 260 Vienna, Austria, Sept. 4-6, 2019
Daniel Reischl et al. / IFAC PapersOnLine 52-15 (2019) 259–264
2.1 Container Manual installation and updating of multiple tools lead to heterogeneous versions of tools within one organization. In combination with complicated user-interfaces, this often prevents the efficient usage of the best suiting tool. Concerning scientific publications, which are based on (the results of a) specific software implementation, are often hard to reproduce as the software is in a current process of adaption and improvement. SyMSpace is therefore using container (generated and executed e.g. with docker, see www.docker.com) to avoid manual or local installation by the user. See Boettiger (2014) for an introduction and Fawaz et al. (2016) for a discussion about advantages and limitations of docker containers. Fig. 1. Automating the design workflow along multiple tools in one SyMSpace model 2. SYMSPACE SyMSpace (acronym for ’System Model Space’) is a software environment for automatic simulation and optimization of parametric models. The tool started with the dreams of not struggling with the GUI of powerful (open source) computation tools anymore, automate the errorprone manual handover of data from one tool to the next and create automatic reports, which was already implemented in the software MagOpt, see Silber et al. (2015). While MagOpt was focused on the efficient automatic design of electric machines, the successor SyMSpace now additionally aims at becoming a knowledge database for all kinds of mechatronic systems, see Foschum et al. (2011) and Reischl et al. (2014). The basic idea is to define parameters, which can be changed by the user, in SyMSpace as fields in a tree-like structure. All necessary computation steps arising from these fields can either be implemented as functions directly in SyMSpace using languages like Java, Python or Matlab or with external tools. Examples for these external tools are finite element software, 3D CAD systems or electric network simulators. The design engineer defines the workflow of the calculation in a SyMSpace model by adding all necessary input parameters and simulation steps into the tree. Results of one calculation will serve as input parameters for the next step, see Fig. 1. If input parameters or intermediate results are changed, SyMSpace automatically tracks which sub(calculation-)steps have to be refreshed. If all external tools are available locally on the same system, it is possible to use SyMSpace as purely local installation on one PC. Often however it is useful or necessary to install tools on special hardware or operating systems. In this case SyMSpace also takes over the distribution of the jobs to different workstations. The results of this automatic workflow typically are reports and data sheets but can also include e.g. data files for laser cutting, STL files for 3D printing or program code for production machines. 729
A container is an instance of an image which contains everything needed for execution (libraries, system tools,..). The minimal configuration of an image for a SyMSpace controlled computation is a basic Python image. In our example the image additionally contains NGSolve and is called lcmlinz/ngsolve on the docker hub. The docker hub is a so-called registry, where images are stored. It is also possible to store images on a private registry. In Fig. 2 it is shown how the computation is done by SyMSpace using the concept of containers: SyMSpace sends a command to docker on the host to start the specified container. If the image is not locally available yet, it would be loaded from the registry automatically. In the container a shared directory is accessible for data exchange with SyMSpace. The calculation is now carried out in the container. After finishing, the results are stored in the shared directory and the container is stopped and deleted. The results are read in from SyMSpace and are ready for further computation steps. 2.2 Optimization Automatic computation of a complete design workflow allows to close the optimization cycle as shown in Fig. 3. The design engineer has to define one or multiple fields in the SyMSpace model as optimization goals and some fields as changeable design parameters including limits for these parameters. Different multiobjective evolutionary algorithms are available to obtain optimal solutions along the pareto frontier efficiently, see Z˘avoianu et al. (2013a), Z˘avoianu et al. (2013c) and Z˘avoianu et al. (2013b). 3. COMPONENTSPACE In order to simplify the set-up of a workflow in a SyMSpace model, predefined components are available. The goal is to collect well documented calculation scripts, simulation models or data-sets which can be reused easily in the ComponentSpace, which therefore also serves as knowledge database. If components are designed such that interfaces are suitable, setting up a complete simulation model of a mechatronic system with multiple computations using different tools can be done within minutes. On the other hand also standalone components exist which are a SyMSpace model on their own.
2019 IFAC MECHATRONICS Vienna, Austria, Sept. 4-6, 2019
Daniel Reischl et al. / IFAC PapersOnLine 52-15 (2019) 259–264
261
m2
m2
m1 m1
m2 m1
m1
m2
m1
m1
Fig. 4. Examples of available ’geometries’ in the PiezoBox (clockwise): LongMPM, RoundBendMPG, RectBendGSMPMSingleSide, LongMSPM
Fig. 2. SyMSpace using the container concept
• conversion tools for material parameters in d- and eformulation, see equations (1) and (2) • analytical models of different geometrical set-ups of the piezoelectric system, see Fig. 4 • finite-element models in NGSolve of some of these geometries • export of the linear system to LTSpice • post-processing like plot and compare transfer functions The base component ’piezo-electric actuator’ requires (a) material parameters from a PiezoCeramic component and (b) a geometrical set-up. For some simulations the full set of material parameters is necessary. They are provided either in e-formulation σ = C E ε − eT E D = eε + ε E
(1)
ε = S E σ + dT E D = dσ + σ E
(2)
or d-formulation
Fig. 3. Closing the optimization cycle
and can be converted with a component in the PiezoBox.
3.1 PiezoBox
Concerning the different geometrical set-ups a consistent syntax for the basic layouts was defined. The name of the component starts with an abbreviation of the piezoelectric component, e.g. ’Long’ (longitudinal actuators), RectBend (rectangular bending actuator) or RoundBend (round bending actuator). The following letters represent sequence of mass (M), spring (S), piezoelectric component (P) and ground (G). For symmetrical set-ups the sequence starts in the center, otherwise with ground. Additional definitions may be added at the end. In Fig. 4 some of the already implemented examples are shown.
Concerning piezoelectric actuators the ComponentSpace already holds the most important components in the PiezoBox, see Reischl et al. (2017), with suitable interfaces for a continous workflow: • a base component for a piezoelectric actuator • material parameters of piezoelectric ceramics from different producers like Johnson Matthey or PI Ceramic 730
2019 IFAC MECHATRONICS Vienna, Austria, Sept. 4-6, 2019 262
Daniel Reischl et al. / IFAC PapersOnLine 52-15 (2019) 259–264
Fig. 6. Circular piezoelectric patch on a rectangular aluminium substrate }401xed surface
With these 3 components (Base Component, Ceramic, Geometry) it is already possible to run simulations. Depending on the implementation this may be analytical computations or finite-element simulations.
n×n
n×1
T
1×n
1
with A ∈ R , b ∈ R , c ∈ R , d ∈ R and electrical potential u. The output y may e.g. be a displacement of a mass or a deflection of an elastic component. The geometry components provide therefore system matrices. These linear models can be converted with a component to an equivalent representation as subsystem in LTSpice (see www.analog.com) and used for a simulation of the overall system including mechanical properties and electrical signals, see Fig. 5 4. CREATE NEW COMPONENT Depending on the type of organization and business model there are multiple reasons why to convert an existing simulation model into a reusable component: • models become available for larger community • models and interfaces have to be described • models are no longer standalone but become a building block for future projects • knowledge database increases continuously • hard job of students and researchers become useful for someone outside the classroom or scientific community • possible revenue based on micro-payments if component is used by third party In this section it is demonstrated how to convert an existing model to a component. 4.1 Convert simulation model to a component As an example of a finite element model in SyMSpace the implementation/integration of a circular piezoelectric patch on a rectangular aluminium substrate using novel mixed finite elements is shown. 731
yp
z
y
b
d
Some of these geometrical set-ups lead to linear analytical models in the form x˙ = Ax + bu (3) y = cT x + du
hp he
xp
Fig. 5. Subsystem in LTSpice, representing the linear mechanical model, can be used for simulation of the overall system
aluminium elektrode ground
x
x
piezo a
Fig. 7. Geometric parameters of the model A sketch of the geometry can be found in Fig. 6. This example has already been published, Meindlhumer and Pechstein (2018). It is implemented in the open source software package Netgen/NGSolve. However, the particular setup is only locally available for the authors and only one configuration was examined. In order to provide an easy and comfortable handling of parameter variations, including geometry and material data, the example is integrated in SyMSpace, converted to a component and made publically available. For the discretisation of the assembly novel 3D mixed finite elements for piezoelectric structures are used. Tangential displacements and normal normal stresses (TDNNS) are used as mechanical degrees of freedom. They have been shown to be free from shear and volumetric locking, Pechstein et al. (2018) and Pechstein (2019). This allows the use of elements with high aspect ratio and reduces the number of degrees of freedom required for a discretization tremendously, especially for flat possibly curved structures, as piezoelectric patch actors are. The finite elements are readily available in open source software package Netgen/NGSolve (see ngsolve.org). In Meindlhumer and Pechstein (2018) the TDNNS method is compared to commercial tools. It was possible to reduce the number of unknowns by a factor of approximately 500 while maintaining accuracy. High accuracy at low computational costs combined with the embedding of method in an open source environment makes the TDNNS methods an ideal candidate of choice for processes where a large number of computations are required e.g. optimization or parameter studies.
2019 IFAC MECHATRONICS Vienna, Austria, Sept. 4-6, 2019
Daniel Reischl et al. / IFAC PapersOnLine 52-15 (2019) 259–264
263
Fig. 8. SyMSpace Model with material parameters (Aluminium and PiezoCeramics) provided by separate components as well as input and output parameters of the finite element model.
Fig. 10. New component available in the ComponentSpace including full documentation
Fig. 9. Parameters are assigned to the interface of the finite element model in the tab ’Import/Export’
provided by other components, like material properties, are placed in the folder ’Testparameter’, in order to be able to test and execute the component standalone.
The following steps have to be taken in order to convert the existing model into a SyMSpace component:
Write documentation For each component a documentation is required which consists at least of the following parts:
Prepare model and interfaces In a first step it is necessary to define the interfaces of the component like e.g. geometrical values and electrical potential as input and eigenfrequencies and a static deflection as output. It is recommended to prepare a descriptive figure already in this step, see Fig. 6 and Fig. 7.
• manually written documentation as structured text • logo identifying the component • tables to describe component parameters are generated automatically. If the text in the field description starts with the symbol ’#’ this parameter is added to the table, see Fig. 8.
Insert model and parameters Add a field in the SyMSpace model for every input and output parameter of your model. If the component is not intended to be standalone or the first (=base) component in the simulation chain, some inputs will be provided by other components, like e.g. material properties of the piezoelectric ceramic, see Fig. 8.
By running the script build component.py the automatically generated tables are built and the full documentation of the component is generated as html-page in the subfolder ’help’. The new component is now available in the ComponentSpace, see Fig. 10.
Add a (preferrably python) function to your model which performs the execution of the simulation tool. The interfaces defined in this function have to be linked to the fields of the input and output parameters in SyMSpace, see Fig. 9. As this component is using Netgen/NGSolve, we will finally use a container, see Section 2.1. For a first test, it is sufficient to use the local installation of Netgen/NGSolve. Press ’Regenerate’ in order to run the component and check the resulting output. Create component with template By running the batch script create component.bat a new component template is created. A pop-up window will appear where the basic information like component name and file directory have to be set and the new component is created in the specified subfolder. Open this template and copy the content of your SyMSpace Model into the template. Those parameters which are 732
4.2 Use component in design process As soon as the component is available in the ComponentSpace it can be used in a design process by others. In a first step we create an empty SyMSpace model and insert an arbitrary piezoelectric ceramic via the component browser. Next our new component can be added analogously. We can now either set the parameters manually and compute the result once, do parameter variations or use the model in an optimization procedure. Fig. 11 and Fig. 12 show the results of a parameter study in which the influence of a change of the patch position [xp , yp ] on the eigenfrequencies was examined. 5. CONCLUSION In this paper the concept of an automatic computation workflow using the tool SyMSpace, well documented components and containers has been presented. Efficient set
2019 IFAC MECHATRONICS 264 Vienna, Austria, Sept. 4-6, 2019
Daniel Reischl et al. / IFAC PapersOnLine 52-15 (2019) 259–264
Fig. 11. First eigenfrequency depends on the x-value xp of the patch position
Fig. 12. Second eigenfrequency depends on both components of the patch position [xp , yp ] up and (public) provision of secure containers and components are still open topics. Concerning this issue, a first test of using SyMSpace in the framework of a lecture on a university has been started in order to motivate students to submit their final projects as components. ACKNOWLEDGEMENTS 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. Martin Meindlhumer acknowledges support of Johannes Kepler University Linz, Linz Institute of Technology (LIT). REFERENCES Boettiger, C. (2014). An introduction to docker for reproducible research, with examples from the r environment. ACM SIGOPS Oper. Syst. Rev., 49. doi: 10.1145/2723872.2723882. 733
Fawaz, P., Challita, S., al dhuraibi, Y., and Merle, P. (2016). Model-driven management of docker containers. In 9th IEEE International Conference on Cloud Computing (CLOUD). doi:10.1109/CLOUD.2016.0100. Fomel, S. and Claerbout, J.F. (2009). Guest editors’ introduction: Reproducible research. Computing in Science Engineering, 11(1), 5–7. doi:10.1109/MCSE.2009.14. Foschum, P., Pl¨ockinger, A., Scheidl, R., Weidenholzer, G., and Winkler, B. (2011). Multi objective genetic optimization of fast switching valves. In Proceedings of the Fourth Workshop on Digital Fluid Power, 116–128. Meindlhumer, M. and Pechstein, A. (2018). 3D mixed finite elements for curved, flat piezoelectric structures. International Journal of Smart and Nano Materials, 1– 19. Online first. Pechstein, A., Meindlhumer, M., and Humer, A. (2018). New mixed finite elements for the discretization of piezoelectric structures or macro-fiber composites. Journal of Intelligent Material Systems and Structures, 29(16), 3266–3283. Pechstein, A.S. (2019). Large deformation mixed finite elements for smart structures. Mechanics of Advanced Materials and Structures, 0(0), 1–11. doi:10.1080/15376494.2018.1536932. URL https://doi.org/10.1080/15376494.2018.1536932. Reischl, D., Dorninger, A., Fohler, A., Gerstmayr, J., Koppelst¨atter, W., Silber, S., and Weitzhofer, S. (2014). Coupled mechanical and electromagnetic optimization of high speed rotors. In Proc. 14th International Symposium on Magnetic Bearings, 247–250. Reischl, D., Nader, M., Kobler, R., Weidenholzer, G., Wenninger, J., and Reininger, A. (2017). Optimales design von piezoelektrisch aktuierten gesamtsystemen. In Smarte Strukturen und Systeme, Tagungsband des 4SMARTS-Symposiums, 21.-22. Juni 2017, Braunschweig, 369–377. Shaker, Aachen. Silber, S., Bramerdorfer, G., Dorninger, A., Fohler, A., Gerstmayr, J., Koppelst¨atter, W., Reischl, D., Weidenholzer, G., and Weitzhofer, S. (2015). Coupled optimization in magopt. Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering. Z˘avoianu, A., Bramerdorfer, G., Lughofer, E., Silber, S., Amrhein, W., and Klement, E. (2013a). A hybrid soft computing approach for optimizing design parameters of electrical drives. Soft Computing Models in Industrial and Environmental Applications, 188, 347–358. Z˘avoianu, A., Lughofer, E., Amrhein, W., and Klement, E. (2013b). Efficient multi-objective optimization using 2population cooperative coevolution. In Computer Aided Systems Theory - EUROCAST 2013, 251–258. Z˘avoianu, A., Lughofer, E., Koppelst¨atter, W., Weidenholzer, G., Amrhein, W., and Klement, E. (2013c). On the performance of master-slave parallelization methods for multi-objective evolutionary algorithms. In L.R. et al. (ed.), Artificial Intelligence and Soft Computing, volume 7895 of Lecture Notes in Artificial Intelligence, 122–134. Springer Berlin Heidelberg.
ScienceDirect
IFAC PapersOnLine 52-15 (2019) 259–264
Components for Simulation of Components for Simulation of Components for Simulation of with piezoelectrically actuated Systems Components for Simulation of with piezoelectrically actuated Systems piezoelectrically actuated Systems SyMSpace piezoelectrically actuated Systems with with SyMSpace SyMSpace SyMSpace Daniel Reischl ∗ Martin Meindlhumer ∗∗ Martin Trinkl ∗∗∗
∗ ∗∗ ∗∗∗ Reischl Meindlhumer Martin ∗ ∗∗ ∗∗∗∗ ∗ Martin ∗∗ Silber ∗∗∗ Reischl Martin Meindlhumer Martin†† Trinkl Trinkl ∗∗∗ Astrid Pechstein ∗∗∗∗ Siegfried ∗ ∗∗ Astrid Martin Pechstein ∗∗∗∗ Siegfried Silber Reischl Meindlhumer Martin†† Trinkl ∗∗∗ ∗∗∗∗ Astrid Pechstein Siegfried Silber Astrid Pechstein ∗∗∗∗ Siegfried Silber † ∗ ∗ Linz Center of Mechatronics GmbH, Linz, Austria (e-mail: Linz Center of Mechatronics GmbH, Linz, Austria (e-mail: ∗ ∗ [email protected]) GmbH, Linz, Austria (e-mail: ∗ Linz Center of Mechatronics [email protected]) ∗∗ Center of Mechatronics Linz GmbH, Linz, Austria (e-mail: [email protected]) University, Linz, Austria (e-mail: ∗∗ Johannes Kepler Kepler University, Linz, Austria (e-mail: ∗∗ [email protected]) ∗∗ Johannes Johannes Kepler University, Linz, Austria (e-mail: [email protected]) ∗∗ ∗∗∗ Johannes [email protected]) Kepler University, Linz,Linz, Austria (e-mail: Mechatronics GmbH, Austria (e-mail: [email protected]) ∗∗∗ Linz Center of Linz Center of Mechatronics GmbH, Linz, Austria (e-mail: ∗∗∗ [email protected]) ∗∗∗ [email protected]) Linz Center of Mechatronics GmbH, Linz, Austria (e-mail: ∗∗∗ [email protected]) ∗∗∗∗ Center of Mechatronics Linz GmbH, Linz, Austria (e-mail: [email protected]) University, Linz, Austria (e-mail: ∗∗∗∗ Johannes Kepler University, Linz, Austria (e-mail: ∗∗∗∗ [email protected]) ∗∗∗∗ Johannes Kepler [email protected]) Johannes Kepler University, Linz, Austria (e-mail: ∗∗∗∗ [email protected]) † Johannes Kepler University, Linz, Austria (e-mail: GmbH, Linz, Austria (e-mail: [email protected]) † Linz Center of Mechatronics Linz Center of Mechatronics GmbH, Linz, Austria (e-mail: † [email protected]) † [email protected]) Linz Center of Mechatronics GmbH, Linz, Austria (e-mail: † [email protected]) Linz Center of Mechatronics GmbH, Linz, Austria (e-mail: [email protected]) [email protected]) Abstract: The concept of automating the computation steps in a design process along different Abstract: The of automating the steps aa design process different Abstract: tools The concept concept the computation computation steps in in design process along along different simulation leads toof aautomating more efficient use of knowledge and computational resources. In simulation tools leads toof aautomating more efficient use of knowledge and computational resources. In Abstract: The concept the computation steps in a design process along different this paper the software tool SyMSpace, which realizes this automatization, and the available simulation tools leads to a more efficient use of knowledge and computational resources. In this paper the software tool SyMSpace, which realizes this automatization, and resources. the available simulation tools leads to a more efficient use of knowledge and computational In components concerning the simulation of which piezoelectrically actuated systems isand presented. this paper the software tool SyMSpace, realizes this automatization, the available components concerning the simulation of which piezoelectrically actuated systems isand presented. this paper the software tool SyMSpace, realizes this automatization, the available The finite element modelthe of simulation a circular piezoelectric patch on a rectangular aluminium substrate components concerning of piezoelectrically actuated systems is presented. The element model of aa circular piezoelectric patch on aa rectangular aluminium substrate components concerning the ofaspiezoelectrically actuated systems is presented. The finite finite modelelements of simulation circular piezoelectric patch on rectangular aluminium substrate using novelelement mixed finite is used an example to show how to create a well-documented using novelelement mixed finite elements is used as an example to show how to create a well-documented The finite model of a circular piezoelectric patch on a rectangular aluminium substrate and easy-to-use component. Tangential displacements and normal normal stresses (TDNNS) are using novel mixed finite elements is used as an example to show how to create a well-documented and easy-to-use component. Tangential displacements and normal normal stresses (TDNNS) are using novel mixed finite elements is used as an example to show how to create a well-documented used as mechanical degrees ofTangential freedom and the finite elements are readily available in open source and easy-to-use component. displacements and normal normal stresses (TDNNS) are used as degrees freedom the are open and easy-to-use displacements and normal normalavailable stresses in (TDNNS) are used as mechanical mechanical degrees of ofTangential freedom and and the finite finite elements elements are readily readily available in open source source software packagecomponent. Netgen/NGSolve. software package Netgen/NGSolve. used as mechanical degrees of freedom theoffinite elements are readily open source software package Netgen/NGSolve. In order to simplify the installation andand usage specialized (open source)available software in tools and help In order to simplify the installation and usage of specialized (open source) software tools and help software package Netgen/NGSolve. to reproduce results in installation scientific publications, concept(open of (docker) is integrated In order to simplify and usage ofthe specialized source)containers software tools and help to reproduce resultsthe in installation scientific publications, concept(open of (docker) is integrated In order to simplify the and usage ofthe specialized source)containers software tools and help in SyMSpace. to reproduce results in scientific publications, the concept of (docker) containers is integrated in to reproduce results in scientific publications, the concept of (docker) containers is integrated in SyMSpace. SyMSpace. © 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. in SyMSpace. Keywords: System Design and Integration, Software Tools, Smart Structures, Smart Keywords: Design and Software Tools, Smart Structures, Smart Keywords: System System and Integration, Integration, Actuators, Motion Design and Vibration Control Software Tools, Smart Structures, Smart Actuators, Motion and Vibration Control Keywords: System and Integration, Actuators, Motion Design and Vibration Control Software Tools, Smart Structures, Smart Actuators, Motion and Vibration Control 1. INTRODUCTION INTRODUCTION As an an example example for for aa mechatronic mechatronic system, system, which which has has to to 1. As 1. INTRODUCTION As an example for a mechatronic system,mechanical which hasand to be modeled in at least 2 domains, namely be in atfor least 2 domains, namely mechanical and 1. INTRODUCTION As modeled an example a mechatronic system, which to be modeled in at least 2 domains, and electrical, piezoelectric actuatornamely is usedmechanical in this has paper. electrical, aa in piezoelectric actuator is used in this paper. be modeled at least 2 domains, namely mechanical and electrical, a piezoelectric actuator is used in this paper. In SyMSpace several predefined piezoelectrically actuated On the the one one hand hand mechatronic mechatronic systems systems are are getting getting more more In SyMSpace several predefined piezoelectrically actuated electrical, piezoelectric actuator is used components in this paper. On In SyMSpace several available predefined actuated systems area already already aspiezoelectrically so-called in On the one hand mechatronic systems on arethe getting more and more complex while simultaneously other hand systems are available as so-called components in In SyMSpace several predefined piezoelectrically actuated and more complex while simultaneously on the other hand systems are already available as so-called components in On the one hand mechatronic systems are getting more order to help the design engineer to set up the overall and more complex while simultaneously on the other hand the need need for for optimization optimization of of the the overall overall system system is is required. required. order to are helpalready the design engineer to set components up the overall systems available as so-called in the toAhelp the design engineer to set and up their the overall andorder moreto complex while simultaneously on the is other hand order system. collection of these these components usage the need for optimization of the overall system required. In address this problem, it is necessary to reduce system. A collection of components and usage order to help the design engineer to set up their the overall In order to address this problem, it is necessary to reduce system. A collection of these components and their usage the need for optimization of the overall system is required. is presented in Section 3. In to address this design problem, it is necessary reduce is theorder complexity for the the engineer as far far as astopossible possible presented in Section system. A collection of 3. these components and their usage the complexity for design engineer as is presented in Section 3. In order to address this problem, it is necessary reduce the complexity for the design engineer as models far astopossible while ensuring, that underlying simulation are still For universities and research departments knowledge knowledge manmanis presented in Section 3. while ensuring, that underlying simulation models are still the complexity for the design engineer as models far as possible universities and research departments while ensuring, that underlying simulation are still For valid and interaction between submodels is represented For universities and research departments knowledge management is essential to make sure, that models and tools valid and interaction between simulation submodels models is represented while ensuring, that underlying are still agement is essential to makedepartments sure, that models and mantools For universities andusable research knowledge valid and The interaction between submodels is significantly represented correctly. relevance of this this approach approach rises agement is essential to make sure, that projects models and tools are available and for follow-up and colcorrectly. The relevance of rises significantly valid and interaction between submodels is significantly represented available and usable for sure, follow-up projects andtools colagement is these essential to make thatpublically models and correctly. relevance of this approach as soon asThe multiple physical domains arerises involved as e.g. e.g. are are available andmodels usable for tools follow-up projects and colleagues. If and are available as soon as multiple physical domains are involved as correctly. relevance this approach significantly If these and are publically available areis aavailable andmodels usable for tools follow-up projects and colas soon asThe multiple physical domains arerises involved as e.g. leagues. electrical, mechanical orofthermal. thermal. leagues. If these models and tools are publically available it contribution to ’reproducable research’, as motivated motivated electrical, or as soon asmechanical multiple physical domains are involved as e.g. it is a contribution to ’reproducable research’, as leagues. If these models and tools are publically available electrical, mechanical or thermal. is abycontribution ’reproducable e.g. Fomel and and to Claerbout (2009).research’, as motivated In many mechanical cases it it is is or sufficient to use use the the results results of of aa it electrical, thermal.to e.g. Fomel Claerbout (2009). it is aby contribution to ’reproducable research’, as motivated In many cases sufficient e.g. by Fomel and Claerbout (2009). In many cases is sufficient use to thetheresults of a In simulation in the theitfirst first domain as astoinput input simulation Section 4 it is therefore presented how to to include include aa e.g. by Fomel and Claerbout (2009). simulation in domain to the simulation In amany cases is sufficient use thetheresults of of a In Section 4 it is therefore presented how simulation in domain. theitfirst domain asto input to simulation in second However the manual transfer In Section 4 it is therefore presented how to include mechanical simulation model of a new piezoelectrically in a second Howeveras the manual transfer of mechanical simulation model of a new piezoelectricallya simulation in domain. the domain input to the simulation In Sectionsystem 4simulation it isastherefore to include in adata second domain. Howevertool the transfer of mechanical the from onefirst simulation tomanual the next is errorerrormodelpresented ofcomponent. a newhow piezoelectrically actuated additional During thisa the data from one simulation tool to the next is in adata second domain. Howeveriftool thetomanual transfer of actuated system as additional component. During this mechanical simulation model of a new piezoelectrically the from one simulation the next is errorprone and may be exhausting done multiple times like actuated system as additional component. During this process, the the developer developer is is enforced enforced to to use use existing existing interfaces interfaces prone andfrom may one be exhausting if done times like process, the data simulation to multiple the 2next is erroractuated system as additional During this prone and may be exhausting during an optimization optimization process.iftool In Section thetimes software done multiple like process, the developer is enforcedcomponent. to use existing interfaces and document the model. during an process. In Section 2 the software prone and may be exhausting if In done multiple like and document the model. process, the developer is enforced to use existing interfaces during an optimization process. Section 2 thetimes software environment SyMSpace is presented which automates this environment SyMSpace process. is presented which automates this and document the model. during anfrom optimization In Section 2 the engineer software environment SyMSpace is presented which automates this and document the model. transfer one tool tool to to the next. next. The design design transfer from one the The engineer environment SyMSpace is presented which automates this transfer from one tool the to the next. The design engineer does not need to learn usage of the different tools but does not from need one to learn the usage of the different tools but transfer tool to the next. The design engineer does not need toon learn the usage can concentrate the design of the overall system. of the different tools but can the the design of of the overall system. doesconcentrate not need toon learn usage different tools but can concentrate on the design of thethe overall system. can concentrate on the design of the overall system. 2405-8963 © 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.
Daniel Daniel Daniel
Copyright © 2019 IFAC 728 Peer review©under of International Federation of Automatic Copyright 2019 responsibility IFAC 728Control. Copyright © 2019 IFAC 728 10.1016/j.ifacol.2019.11.684 Copyright © 2019 IFAC 728
2019 IFAC MECHATRONICS 260 Vienna, Austria, Sept. 4-6, 2019
Daniel Reischl et al. / IFAC PapersOnLine 52-15 (2019) 259–264
2.1 Container Manual installation and updating of multiple tools lead to heterogeneous versions of tools within one organization. In combination with complicated user-interfaces, this often prevents the efficient usage of the best suiting tool. Concerning scientific publications, which are based on (the results of a) specific software implementation, are often hard to reproduce as the software is in a current process of adaption and improvement. SyMSpace is therefore using container (generated and executed e.g. with docker, see www.docker.com) to avoid manual or local installation by the user. See Boettiger (2014) for an introduction and Fawaz et al. (2016) for a discussion about advantages and limitations of docker containers. Fig. 1. Automating the design workflow along multiple tools in one SyMSpace model 2. SYMSPACE SyMSpace (acronym for ’System Model Space’) is a software environment for automatic simulation and optimization of parametric models. The tool started with the dreams of not struggling with the GUI of powerful (open source) computation tools anymore, automate the errorprone manual handover of data from one tool to the next and create automatic reports, which was already implemented in the software MagOpt, see Silber et al. (2015). While MagOpt was focused on the efficient automatic design of electric machines, the successor SyMSpace now additionally aims at becoming a knowledge database for all kinds of mechatronic systems, see Foschum et al. (2011) and Reischl et al. (2014). The basic idea is to define parameters, which can be changed by the user, in SyMSpace as fields in a tree-like structure. All necessary computation steps arising from these fields can either be implemented as functions directly in SyMSpace using languages like Java, Python or Matlab or with external tools. Examples for these external tools are finite element software, 3D CAD systems or electric network simulators. The design engineer defines the workflow of the calculation in a SyMSpace model by adding all necessary input parameters and simulation steps into the tree. Results of one calculation will serve as input parameters for the next step, see Fig. 1. If input parameters or intermediate results are changed, SyMSpace automatically tracks which sub(calculation-)steps have to be refreshed. If all external tools are available locally on the same system, it is possible to use SyMSpace as purely local installation on one PC. Often however it is useful or necessary to install tools on special hardware or operating systems. In this case SyMSpace also takes over the distribution of the jobs to different workstations. The results of this automatic workflow typically are reports and data sheets but can also include e.g. data files for laser cutting, STL files for 3D printing or program code for production machines. 729
A container is an instance of an image which contains everything needed for execution (libraries, system tools,..). The minimal configuration of an image for a SyMSpace controlled computation is a basic Python image. In our example the image additionally contains NGSolve and is called lcmlinz/ngsolve on the docker hub. The docker hub is a so-called registry, where images are stored. It is also possible to store images on a private registry. In Fig. 2 it is shown how the computation is done by SyMSpace using the concept of containers: SyMSpace sends a command to docker on the host to start the specified container. If the image is not locally available yet, it would be loaded from the registry automatically. In the container a shared directory is accessible for data exchange with SyMSpace. The calculation is now carried out in the container. After finishing, the results are stored in the shared directory and the container is stopped and deleted. The results are read in from SyMSpace and are ready for further computation steps. 2.2 Optimization Automatic computation of a complete design workflow allows to close the optimization cycle as shown in Fig. 3. The design engineer has to define one or multiple fields in the SyMSpace model as optimization goals and some fields as changeable design parameters including limits for these parameters. Different multiobjective evolutionary algorithms are available to obtain optimal solutions along the pareto frontier efficiently, see Z˘avoianu et al. (2013a), Z˘avoianu et al. (2013c) and Z˘avoianu et al. (2013b). 3. COMPONENTSPACE In order to simplify the set-up of a workflow in a SyMSpace model, predefined components are available. The goal is to collect well documented calculation scripts, simulation models or data-sets which can be reused easily in the ComponentSpace, which therefore also serves as knowledge database. If components are designed such that interfaces are suitable, setting up a complete simulation model of a mechatronic system with multiple computations using different tools can be done within minutes. On the other hand also standalone components exist which are a SyMSpace model on their own.
2019 IFAC MECHATRONICS Vienna, Austria, Sept. 4-6, 2019
Daniel Reischl et al. / IFAC PapersOnLine 52-15 (2019) 259–264
261
m2
m2
m1 m1
m2 m1
m1
m2
m1
m1
Fig. 4. Examples of available ’geometries’ in the PiezoBox (clockwise): LongMPM, RoundBendMPG, RectBendGSMPMSingleSide, LongMSPM
Fig. 2. SyMSpace using the container concept
• conversion tools for material parameters in d- and eformulation, see equations (1) and (2) • analytical models of different geometrical set-ups of the piezoelectric system, see Fig. 4 • finite-element models in NGSolve of some of these geometries • export of the linear system to LTSpice • post-processing like plot and compare transfer functions The base component ’piezo-electric actuator’ requires (a) material parameters from a PiezoCeramic component and (b) a geometrical set-up. For some simulations the full set of material parameters is necessary. They are provided either in e-formulation σ = C E ε − eT E D = eε + ε E
(1)
ε = S E σ + dT E D = dσ + σ E
(2)
or d-formulation
Fig. 3. Closing the optimization cycle
and can be converted with a component in the PiezoBox.
3.1 PiezoBox
Concerning the different geometrical set-ups a consistent syntax for the basic layouts was defined. The name of the component starts with an abbreviation of the piezoelectric component, e.g. ’Long’ (longitudinal actuators), RectBend (rectangular bending actuator) or RoundBend (round bending actuator). The following letters represent sequence of mass (M), spring (S), piezoelectric component (P) and ground (G). For symmetrical set-ups the sequence starts in the center, otherwise with ground. Additional definitions may be added at the end. In Fig. 4 some of the already implemented examples are shown.
Concerning piezoelectric actuators the ComponentSpace already holds the most important components in the PiezoBox, see Reischl et al. (2017), with suitable interfaces for a continous workflow: • a base component for a piezoelectric actuator • material parameters of piezoelectric ceramics from different producers like Johnson Matthey or PI Ceramic 730
2019 IFAC MECHATRONICS Vienna, Austria, Sept. 4-6, 2019 262
Daniel Reischl et al. / IFAC PapersOnLine 52-15 (2019) 259–264
Fig. 6. Circular piezoelectric patch on a rectangular aluminium substrate }401xed surface
With these 3 components (Base Component, Ceramic, Geometry) it is already possible to run simulations. Depending on the implementation this may be analytical computations or finite-element simulations.
n×n
n×1
T
1×n
1
with A ∈ R , b ∈ R , c ∈ R , d ∈ R and electrical potential u. The output y may e.g. be a displacement of a mass or a deflection of an elastic component. The geometry components provide therefore system matrices. These linear models can be converted with a component to an equivalent representation as subsystem in LTSpice (see www.analog.com) and used for a simulation of the overall system including mechanical properties and electrical signals, see Fig. 5 4. CREATE NEW COMPONENT Depending on the type of organization and business model there are multiple reasons why to convert an existing simulation model into a reusable component: • models become available for larger community • models and interfaces have to be described • models are no longer standalone but become a building block for future projects • knowledge database increases continuously • hard job of students and researchers become useful for someone outside the classroom or scientific community • possible revenue based on micro-payments if component is used by third party In this section it is demonstrated how to convert an existing model to a component. 4.1 Convert simulation model to a component As an example of a finite element model in SyMSpace the implementation/integration of a circular piezoelectric patch on a rectangular aluminium substrate using novel mixed finite elements is shown. 731
yp
z
y
b
d
Some of these geometrical set-ups lead to linear analytical models in the form x˙ = Ax + bu (3) y = cT x + du
hp he
xp
Fig. 5. Subsystem in LTSpice, representing the linear mechanical model, can be used for simulation of the overall system
aluminium elektrode ground
x
x
piezo a
Fig. 7. Geometric parameters of the model A sketch of the geometry can be found in Fig. 6. This example has already been published, Meindlhumer and Pechstein (2018). It is implemented in the open source software package Netgen/NGSolve. However, the particular setup is only locally available for the authors and only one configuration was examined. In order to provide an easy and comfortable handling of parameter variations, including geometry and material data, the example is integrated in SyMSpace, converted to a component and made publically available. For the discretisation of the assembly novel 3D mixed finite elements for piezoelectric structures are used. Tangential displacements and normal normal stresses (TDNNS) are used as mechanical degrees of freedom. They have been shown to be free from shear and volumetric locking, Pechstein et al. (2018) and Pechstein (2019). This allows the use of elements with high aspect ratio and reduces the number of degrees of freedom required for a discretization tremendously, especially for flat possibly curved structures, as piezoelectric patch actors are. The finite elements are readily available in open source software package Netgen/NGSolve (see ngsolve.org). In Meindlhumer and Pechstein (2018) the TDNNS method is compared to commercial tools. It was possible to reduce the number of unknowns by a factor of approximately 500 while maintaining accuracy. High accuracy at low computational costs combined with the embedding of method in an open source environment makes the TDNNS methods an ideal candidate of choice for processes where a large number of computations are required e.g. optimization or parameter studies.
2019 IFAC MECHATRONICS Vienna, Austria, Sept. 4-6, 2019
Daniel Reischl et al. / IFAC PapersOnLine 52-15 (2019) 259–264
263
Fig. 8. SyMSpace Model with material parameters (Aluminium and PiezoCeramics) provided by separate components as well as input and output parameters of the finite element model.
Fig. 10. New component available in the ComponentSpace including full documentation
Fig. 9. Parameters are assigned to the interface of the finite element model in the tab ’Import/Export’
provided by other components, like material properties, are placed in the folder ’Testparameter’, in order to be able to test and execute the component standalone.
The following steps have to be taken in order to convert the existing model into a SyMSpace component:
Write documentation For each component a documentation is required which consists at least of the following parts:
Prepare model and interfaces In a first step it is necessary to define the interfaces of the component like e.g. geometrical values and electrical potential as input and eigenfrequencies and a static deflection as output. It is recommended to prepare a descriptive figure already in this step, see Fig. 6 and Fig. 7.
• manually written documentation as structured text • logo identifying the component • tables to describe component parameters are generated automatically. If the text in the field description starts with the symbol ’#’ this parameter is added to the table, see Fig. 8.
Insert model and parameters Add a field in the SyMSpace model for every input and output parameter of your model. If the component is not intended to be standalone or the first (=base) component in the simulation chain, some inputs will be provided by other components, like e.g. material properties of the piezoelectric ceramic, see Fig. 8.
By running the script build component.py the automatically generated tables are built and the full documentation of the component is generated as html-page in the subfolder ’help’. The new component is now available in the ComponentSpace, see Fig. 10.
Add a (preferrably python) function to your model which performs the execution of the simulation tool. The interfaces defined in this function have to be linked to the fields of the input and output parameters in SyMSpace, see Fig. 9. As this component is using Netgen/NGSolve, we will finally use a container, see Section 2.1. For a first test, it is sufficient to use the local installation of Netgen/NGSolve. Press ’Regenerate’ in order to run the component and check the resulting output. Create component with template By running the batch script create component.bat a new component template is created. A pop-up window will appear where the basic information like component name and file directory have to be set and the new component is created in the specified subfolder. Open this template and copy the content of your SyMSpace Model into the template. Those parameters which are 732
4.2 Use component in design process As soon as the component is available in the ComponentSpace it can be used in a design process by others. In a first step we create an empty SyMSpace model and insert an arbitrary piezoelectric ceramic via the component browser. Next our new component can be added analogously. We can now either set the parameters manually and compute the result once, do parameter variations or use the model in an optimization procedure. Fig. 11 and Fig. 12 show the results of a parameter study in which the influence of a change of the patch position [xp , yp ] on the eigenfrequencies was examined. 5. CONCLUSION In this paper the concept of an automatic computation workflow using the tool SyMSpace, well documented components and containers has been presented. Efficient set
2019 IFAC MECHATRONICS 264 Vienna, Austria, Sept. 4-6, 2019
Daniel Reischl et al. / IFAC PapersOnLine 52-15 (2019) 259–264
Fig. 11. First eigenfrequency depends on the x-value xp of the patch position
Fig. 12. Second eigenfrequency depends on both components of the patch position [xp , yp ] up and (public) provision of secure containers and components are still open topics. Concerning this issue, a first test of using SyMSpace in the framework of a lecture on a university has been started in order to motivate students to submit their final projects as components. ACKNOWLEDGEMENTS 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. Martin Meindlhumer acknowledges support of Johannes Kepler University Linz, Linz Institute of Technology (LIT). REFERENCES Boettiger, C. (2014). An introduction to docker for reproducible research, with examples from the r environment. ACM SIGOPS Oper. Syst. Rev., 49. doi: 10.1145/2723872.2723882. 733
Fawaz, P., Challita, S., al dhuraibi, Y., and Merle, P. (2016). Model-driven management of docker containers. In 9th IEEE International Conference on Cloud Computing (CLOUD). doi:10.1109/CLOUD.2016.0100. Fomel, S. and Claerbout, J.F. (2009). Guest editors’ introduction: Reproducible research. Computing in Science Engineering, 11(1), 5–7. doi:10.1109/MCSE.2009.14. Foschum, P., Pl¨ockinger, A., Scheidl, R., Weidenholzer, G., and Winkler, B. (2011). Multi objective genetic optimization of fast switching valves. In Proceedings of the Fourth Workshop on Digital Fluid Power, 116–128. Meindlhumer, M. and Pechstein, A. (2018). 3D mixed finite elements for curved, flat piezoelectric structures. International Journal of Smart and Nano Materials, 1– 19. Online first. Pechstein, A., Meindlhumer, M., and Humer, A. (2018). New mixed finite elements for the discretization of piezoelectric structures or macro-fiber composites. Journal of Intelligent Material Systems and Structures, 29(16), 3266–3283. Pechstein, A.S. (2019). Large deformation mixed finite elements for smart structures. Mechanics of Advanced Materials and Structures, 0(0), 1–11. doi:10.1080/15376494.2018.1536932. URL https://doi.org/10.1080/15376494.2018.1536932. Reischl, D., Dorninger, A., Fohler, A., Gerstmayr, J., Koppelst¨atter, W., Silber, S., and Weitzhofer, S. (2014). Coupled mechanical and electromagnetic optimization of high speed rotors. In Proc. 14th International Symposium on Magnetic Bearings, 247–250. Reischl, D., Nader, M., Kobler, R., Weidenholzer, G., Wenninger, J., and Reininger, A. (2017). Optimales design von piezoelektrisch aktuierten gesamtsystemen. In Smarte Strukturen und Systeme, Tagungsband des 4SMARTS-Symposiums, 21.-22. Juni 2017, Braunschweig, 369–377. Shaker, Aachen. Silber, S., Bramerdorfer, G., Dorninger, A., Fohler, A., Gerstmayr, J., Koppelst¨atter, W., Reischl, D., Weidenholzer, G., and Weitzhofer, S. (2015). Coupled optimization in magopt. Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering. Z˘avoianu, A., Bramerdorfer, G., Lughofer, E., Silber, S., Amrhein, W., and Klement, E. (2013a). A hybrid soft computing approach for optimizing design parameters of electrical drives. Soft Computing Models in Industrial and Environmental Applications, 188, 347–358. Z˘avoianu, A., Lughofer, E., Amrhein, W., and Klement, E. (2013b). Efficient multi-objective optimization using 2population cooperative coevolution. In Computer Aided Systems Theory - EUROCAST 2013, 251–258. Z˘avoianu, A., Lughofer, E., Koppelst¨atter, W., Weidenholzer, G., Amrhein, W., and Klement, E. (2013c). On the performance of master-slave parallelization methods for multi-objective evolutionary algorithms. In L.R. et al. (ed.), Artificial Intelligence and Soft Computing, volume 7895 of Lecture Notes in Artificial Intelligence, 122–134. Springer Berlin Heidelberg.