Proceedings of the 7 International Modelica Conference Como, Italy

Braig, Thomas; Ungethüm, Jörg

doi:10.3384/ecp0943

Cited by 9 publications

(4 citation statements)

References 2 publications

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“…Staying in frame of the spatial multibody dynamics classes previously developed [4,5] it is quite natural to use additional rigid body C playing the role of platform, for implementing a relative planar motion of the bodies, two gearwheels denoted as A and B in our case. These bodies assumed to have cylindrical shapes and are able to move in the plane orthogonal to their generatrix.…”

Section: Cylindrical Symmetry Of 3d-bodies Contactmentioning

confidence: 99%

“…The geometrical properties have been implemented as a class parameter for the base template described in [5] for the model outlined above with contact of involutes. Along with the geometrical properties model, the contact elastic normal force model plays a key role as well.…”

Section: Contact Force Modelmentioning

confidence: 99%

“…As it was already mentioned the template ContactConstraintBaseTemplate developed earlier [5] has been applied for implementing the contact model of two gearwheels with spur involute gearing. The template has four class parameters defining models of: (a) the normal elastic force, (b) the normal force of viscous resistance, (c) the tangent force of resistance for relative slipping at contact, (d) geometry of surfaces in vicinity of contact, in our case they are the cylinders guided by an involute.…”

Section: Some Details Of Implementationmentioning

confidence: 99%

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Implementation of the Spur Involute Gear Model on Modelica

Kosenko

Gusev

2011

Linköping Electronic Conference Proceedings

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A procedure to build up a dynamical model of the gearbox with spur involute mesh is being described. The main attention is paid to the design technology of the cylindrical bodies elastic contact models. To track geometry of contact implicit equations of algebraic/transcendental or differential-algebraic type are being used. At the same time dynamical models of the bodies involved, gearwheels and gearbox housing, continue to be three-dimensional. Analytical computational procedures to obtain gradients and Hessians are constructed for implementing the contact tracking algorithm for the involute guided cylindrical surfaces. The known Johnson model is applied for computing the contact elastic normal force. This force is defined as an implicit function of the mutual penetration depth at contact. Regular algorithm to compute the normal elastic force is built up. This algorithm is proved to be convergent. A detailed analysis of the virtual setup dynamic model is carried out.

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Section: Cylindrical Symmetry Of 3d-bodies Contactmentioning

confidence: 99%

Section: Contact Force Modelmentioning

confidence: 99%

Section: Some Details Of Implementationmentioning

confidence: 99%

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Implementation of the Spur Involute Gear Model on Modelica

Kosenko

Gusev

2011

Linköping Electronic Conference Proceedings

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“…The standard Modelica language is used by several thousand developers including people developing large industrial applications, many of which are described in Modelica conference proceedings [10,26,32,102,146].…”

Section: Introductionmentioning

confidence: 99%

Tools and Methods for Analysis, Debugging, and Performance Improvement of Equation-Based Models

Sjölund¹

2015

Linköping Studies in Science and Technology. Dissertations

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Equation-based object-oriented (EOO) modeling languages such as Modelica provide a convenient, declarative method for describing models of cyber-physical systems. Because of the ease of use of EOO languages, large and complex models can be built with limited effort. However, current state-of-the-art tools do not provide the user with enough information when errors appear or simulation results are wrong. It is of paramount importance that such tools should give the user enough information to correct errors or understand where the problems that lead to wrong simulation results are located. However, understanding the model translation process of an EOO compiler is a daunting task that not only requires knowledge of the numerical algorithms that the tool executes during simulation, but also the complex symbolic transformations being performed.As part of this work, methods have been developed and explored where the EOO tool, an enhanced Modelica compiler, records the transformations during the translation process in order to provide better diagnostics, explanations, and analysis. This information is used to generate better error-messages during translation. It is also used to provide better debugging for a simulation that produces unexpected results or where numerical methods fail.Meeting deadlines is particularly important for real-time applications. It is usually essential to identify possible bottlenecks and either simplify the model or give hints to the compiler that enable it to generate faster code. When profiling and measuring execution times of parts of the model the recorded information can also be used to find out why a particular system model executes slowly.Combined with debugging information, it is possible to find out why this system of equations is slow to solve, which helps understanding what can be done to simplify the model. A tool with a graphical user interface has been developed to make debugging and performance profiling easier. Both debugging and profiling have been combined into a single view so that performance metrics are mapped to equations, which are mapped to debugging information.The algorithmic part of Modelica was extended with meta-modeling constructs (MetaModelica) for language modeling. In this context a quite general approach to debugging and compilation from (extended) Modelica to C code was developed. That makes it possible to use the same executable format for simulation executables as for compiler bootstrapping when the compiler written in MetaModelica compiles itself.Finally, a method and tool prototype suitable for speeding up simulations has been developed. It works by partitioning the model at appropriate places and compiling a simulation executable for a suitable parallel platform. Populärvetenskaplig sammanfattningSom ingenjör lär man sig att förstå världen genom ekvationer. För att beskriva eller modellera ett fysikaliskt system, till exempel vid utveckling av en produkt, vill ingenjören använda sig av de ekvationer som han eller hon lärt sig från böcker eller fö...

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