@inproceedings{BuenteRillRuggaberetal., author = {B{\"u}nte, Tilman and Rill, Georg and Ruggaber, Julian and Tobol{\´a}ř, Jakub}, title = {Modelling and Validation of the TMeasy Tyre Model for Extreme Parking Manoeuvres}, series = {Advances in Dynamics of Vehicles on Roads and Tracks II, Proceedings of the 27th Symposium of the International Association of Vehicle System Dynamics (IAVSD 2021): August 17-19, 2021, Saint Petersburg, Russia}, booktitle = {Advances in Dynamics of Vehicles on Roads and Tracks II, Proceedings of the 27th Symposium of the International Association of Vehicle System Dynamics (IAVSD 2021): August 17-19, 2021, Saint Petersburg, Russia}, editor = {Orlova, Anna and Cole, David}, publisher = {Springer}, address = {Cham}, isbn = {978-3-031-07305-2}, doi = {10.1007/978-3-031-07305-2_94}, pages = {1015 -- 1025}, abstract = {The TMeasy is a tyre model suitable for vehicle handling analyses and enables easy parametrisation. Recently, a convenient interface to Modelica was implemented by DLR to support the TMeasy also for vehicle modelling in multi-physical domains. This paper focuses especially on the particular problem of reliable reproduction of the tyre's bore torque which occurs during parking manoeuvres. It outlines the theory behind it, discusses the Modelica interface implementation, and presents the results of parameter identification which were achieved based on real experiments with DLR's research platform ROboMObil.}, language = {en} } @article{RillBauerTopcagic, author = {Rill, Georg and Bauer, Florian and Topcagic, Edin}, title = {Performance of leaf spring suspended axles in model approaches of different complexities}, series = {Vehicle System Dynamics}, volume = {60}, journal = {Vehicle System Dynamics}, number = {8}, publisher = {Taylor\&Francis}, doi = {10.1080/00423114.2021.1928249}, pages = {2871 -- 2889}, abstract = {Axles with leaf spring suspension systems are still a popular choice in many commercial vehicles. However, leaf springs are not in perfect conformity to standard multibody vehicle models because they combine guidance and suspension in one single element. Combining standard multibody vehicle models with sophisticated finite element leaf spring models results in rather complex and computing time-consuming solutions. Purely kinematic models, defined by lookup tables or the design kinematics approach, cover only some but not all features of the leaf spring suspension. As shown here, the five-link model, which incorporates a quasi-static solution of the leaf spring compliance, provides a very practical model. It is comparatively lean and provides results of sufficient accuracy in the whole application range.}, language = {en} } @article{BruniMeijaardRilletal., author = {Bruni, S. and Meijaard, J. P. and Rill, Georg and Schwab, A. L.}, title = {State-of-the-art and challenges of railway and road vehicle dynamics with multibody dynamics approaches}, series = {Multibody System Dynamics}, volume = {49}, journal = {Multibody System Dynamics}, number = {1}, publisher = {Springer}, doi = {10.1007/s11044-020-09735-z}, pages = {1 -- 32}, abstract = {A review of the current use of multibody dynamics methods in the analysis of the dynamics of vehicles is given. Railway vehicle dynamics as well as road vehicle dynamics are considered, where for the latter the dynamics of cars and trucks and the dynamics of single-track vehicles, in particular motorcycles and bicycles, are reviewed. Commonalities and differences are shown, and open questions and challenges are given as directions for further research in this field.}, language = {en} } @article{RillBauerKirchbeck, author = {Rill, Georg and Bauer, Florian and Kirchbeck, Mathias}, title = {VTT - a virtual test truck for modern simulation tasks}, series = {Vehicle system dynamics}, volume = {59}, journal = {Vehicle system dynamics}, number = {4}, publisher = {Taylor\&Francis}, doi = {10.1080/00423114.2019.1705356}, pages = {635 -- 656}, abstract = {The development of new technologies like advanced driver assistance systems or automated driving requires a flexible simulation environment of sufficient complexity. In general this flexibility is not provided by commercial software packages. This paper presents a three-dimensional and nonlinear hand-made model for heavy commercial vehicles including tractor and trailer as well as tractor and semitrailer combinations that can be used in different simulation environments, as well as in real-time applications. As typical for trucks, the torsional flexibility of the frame and a suspended driver's cabin are taken into account. The design kinematics makes it possible to handle different and quite complex axle suspensions very efficiently. Appropriate force elements are used to model various couplings between tractor and trailer or tractor and semitrailer, respectively. The virtual test truck environment (VTT) coded in ANSI C is extremely portable and can easily be embedded in commercial simulation packages like MATLAB/Simulink. It includes the TMeasy tyre model and offers flexible interfaces to third-party software tools.}, language = {en} } @article{Rill, author = {Rill, Georg}, title = {Sophisticated but quite simple contact calculation for handling tire models}, series = {Multibody system dynamics}, volume = {45}, journal = {Multibody system dynamics}, number = {2}, publisher = {Springer Nature}, organization = {SPRINGER}, doi = {10.1007/s11044-018-9629-4}, pages = {131 -- 153}, abstract = {Handling tire models like Pacejka (Tire and Vehicle Dynamics, 3rd edn., Elsevier, Amsterdam, 2012) or TMeasy (Rill in Proc. of the XV Int. Symp. on Dynamic Problems of Mechanics, Buzios, RJ, Brazil, 2013) consider the contact patch as one coherent plane. As a consequence, the irregularities of a rough road profile must be approximated by an appropriate local road plane that serves as an effective road plane in order to calculate the geometric contact point and the corresponding contact velocities. The Pacejka/SWIFT tire model employs a road enveloping model that generates the effective height and slope by elliptical cams. TMeasy just uses four representative road points for that purpose. In addition, TMeasy replaces the geometric contact point by the static contact point and shifts it finally to the dynamic contact point that represents the point where the contact forces are applied. In doing so, a rather sophisticated but still simple contact calculation is possible. Simulations obtained with a virtual tire test rig and fully nonlinear three-dimensional multibody system models of a motor-scooter and a passenger car demonstrate the potential of this contact approach.}, language = {en} } @inproceedings{HacklHirschbergLexetal., author = {Hackl, Andreas and Hirschberg, Wolfgang and Lex, Cornelia and Rill, Georg}, title = {Parameterization Process of the Maxwell Model to Describe the Transient Force Behavior of a Tire}, series = {WCX 17: SAE World Congress Experience 2017}, booktitle = {WCX 17: SAE World Congress Experience 2017}, publisher = {SAE}, doi = {10.4271/2017-01-1505}, abstract = {The present technical article deals with the modeling of dynamic tire forces, which are relevant during interactions of safety relevant Advanced Driver Assistance Systems (ADAS). Special attention has been paid on simple but effective tire modeling of semi-physical type. In previous investigations, experimental validation showed that the well-known first-order Kelvin-Voigt model, described by a spring and damper element, describes good suitability around fixed operation points, but is limited for a wide working range. When aiming to run vehicle dynamics models within a frequency band of excitation up to 8 Hz, these models deliver remarkable deviations from measured tire characteristics. To overcome this limitation, a nonlinear Maxwell spring-damper element was introduced which is qualified to model the dynamic hardening of the elastomer materials of the tire. However, the advantage of a more realistic description of the transient behavior leads to a more complex parametrization process. Therefore, in the proposed article attention is paid to describe the identification process including defined maneuvers to parameterize the tire model, where the accuracy of the parameter strongly depends on the quality of the available input data from measurement. In order to study this important aspect of parameterization, the reference data from simulation of the full physical tire model FTire is applied like a "virtual measurement" of specified testing maneuvers. The procedure of simulation by means of the enhanced first order dynamics model is implemented by the semi-physical tire model TMeasy. Finally, the improvements of the extended model are discussed and an outlook for future work is given.}, language = {en} } @inproceedings{RillArrietaCastro, author = {Rill, Georg and Arrieta Castro, Abel}, title = {The Influence of Axle Kinematics on Vehicle Dynamics}, series = {Interdisciplinary Applications of Kinematics. Proceedings of the Third International Conference (IAK)}, volume = {71}, booktitle = {Interdisciplinary Applications of Kinematics. Proceedings of the Third International Conference (IAK)}, editor = {Kecskem{\´e}thy, Andr{\´e}s and Geu Flores, Francisco and Carrera, Eliodoro and Elias, Dante A.}, publisher = {Springer International Publishing}, address = {Cham}, isbn = {978-3-030-16422-5}, doi = {10.1007/978-3-030-16423-2_2}, pages = {23 -- 31}, abstract = {The automotive industry employs many different kinds of axle suspension systems at modern passenger cars. Important criteria are costs, space requirements, kinematic properties, and compliance attributes. This paper illustrates that in particular the kinematic properties of a suspension system have a significant influence on the dynamics of vehicles. As a consequence, the kinematics of a suspension system must be modeled very precisely and nonlinear. Typical kinematical features of a suspension system are discussed by analyzing the most common double wishbone axle suspension system. The influence of the axle kinematics on vehicle dynamics is finally demonstrated by simulation results generated with a fully nonlinear and three-dimensional multibody vehicle model.}, language = {en} } @inproceedings{ArrietaCastroRill, author = {Arrieta Castro, Abel and Rill, Georg}, title = {Kinematic Versus Elasto-Kinematic Model of a Twistbeam Suspension}, series = {Advances in Dynamics of Vehicles on Roads and Tracks II, proceedings of the 27th Symposium of the International Association of Vehicle System Dynamics (IAVSD 2021): August 17-19, 2021, Saint Petersburg, Russia}, booktitle = {Advances in Dynamics of Vehicles on Roads and Tracks II, proceedings of the 27th Symposium of the International Association of Vehicle System Dynamics (IAVSD 2021): August 17-19, 2021, Saint Petersburg, Russia}, editor = {Orlova, Anna and Cole, David}, publisher = {Springer Nature}, doi = {10.1007/978-3-031-07305-2_59}, pages = {505 -- 605}, abstract = {The Twistbeam axle suspension is a cheap and robust layout for rear axles at front wheel driven midsize cars. Appropriate models have to take the elastic deformation of the torsion beam into account. A Finite Element approach requires detailed informations of the material properties and the shape which are usually only available in the final production stage. This paper presents a lumped mass model which can easily be integrated into a multibody vehicle model and can be used in the early stage of development. An approximation by the design kinematics further reduces the complexity of the model and considers only the kinematic properties of the Twistbeam suspension. Simulations using a nonlinear and three-dimensional vehicle model with different maneuvers, such as steady-state cornering, step steer input, and driving straight ahead on random road, demonstrate the performance and, in particular, the difference of the presented Twistbeam suspension models.}, language = {en} } @article{HirschbergRillWeinfurter, author = {Hirschberg, Wolfgang and Rill, Georg and Weinfurter, H.}, title = {Tire model TMeasy}, series = {Vehicle System Dynamics}, volume = {45}, journal = {Vehicle System Dynamics}, number = {sup1}, publisher = {Taylor\&Francis}, doi = {10.1080/00423110701776284}, pages = {101 -- 119}, abstract = {This paper describes the semi-physical tire model TMeasy for vehicle dynamics and handling analyses, as it was applied in the 'low frequency tire models' section of the research programme tire model performance test (TMPT). Despite more or less weak testing input data, the effort for the application of TMeasy remains limited due to its consequent 'easy to use' orientation. One particular feature of TMeasy is the wide physical meaning of its smart parameter set, which allows to sustain the identification process even under uncertain conditions. After a general introduction, the modelling concept of TMeasy is compactly described in this paper. Taking the standard tire interface (STI) to multibody simulation system (MBS) software into account, the way to apply TMeasy is briefly shown. This includes three selected examples of application. The final comments of the authors on TMPT describe the experiences and earnings received during the participation in that programme.}, language = {en} } @article{SchudererRillSchaefferetal., author = {Schuderer, Matthias and Rill, Georg and Schaeffer, Thomas and Schulz, Carsten}, title = {Friction modeling from a practical point of view}, series = {Multibody System Dynamics}, journal = {Multibody System Dynamics}, publisher = {Springernature}, issn = {1384-5640}, doi = {10.1007/s11044-024-09978-0}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-72513}, pages = {18}, abstract = {AbstractRegularized static friction models have been used successfully for many years. However, they are unable to maintain static friction in detail. For this reason, dynamic friction models have been developed and published in the literature. However, commercial multibody simulation packages such as Adams, RecurDyn, and Simpack have developed their own specific stick-slip models instead of adopting one of the public domain approaches. This article introduces the fundamentals of these commercial models and their behavior from a practical point of view. The stick-slip models were applied to a simple test model and a more sophisticated model of a festoon cable system using their standard parameters.}, language = {en} } @article{RillSchaefferSchuderer, author = {Rill, Georg and Schaeffer, Thomas and Schuderer, Matthias}, title = {LuGre or not LuGre}, series = {Multibody System Dynamics}, journal = {Multibody System Dynamics}, publisher = {Springer}, doi = {10.1007/s11044-023-09909-5}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:898-opus4-65653}, pages = {28}, abstract = {The LuGre model is widely used in the analysis and control of systems with friction. Recently, it has even been made available in the commercial multibody dynamics simulation software system Adams. However, the LuGre model exhibits well-known drawbacks like too low and force rate-dependent break-away forces, drift problems during sticking periods, and significant differences in non-stationary situations between the pre-defined friction law and the one produced by the LuGre model. In the present literature, these problems are supposed to come from the model dynamics or its nonlinear nature. However, most of these drawbacks are not simple side effects of a dynamic friction model but are caused in the LuGre approach, as shown here, by a too simple and inconsistent model of the bristle dynamics. Standard examples and a more practical application demonstrate that the LuGre model is not a "what you see is what you get" approach. A dynamic friction model with accurate bristle dynamics and consistent friction force is set up here. It provides insight into the physical basis of the LuGre model dynamics. However, it results in a nonlinear and implicit differential equation, whose solution will not be easy because of the ambiguity of the friction characteristics. The standard workaround, a static model based on simple regularized characteristics, produces reliable and generally satisfactory results but definitely cannot maintain a stick. The paper presents a second-order dynamic friction model, which may serve as an alternative. It can maintain a stick and produces realistic and reliable results.}, language = {en} }