Pub Date : 1900-01-01DOI: 10.3311/eccomasmbd2021-233
Felix Aller, M. Harant, K. Mombaur
In this paper, we describe an approach for the model identification of the humanoid robot REEM-C. In contrast to previous work, we do not attempt to determine all dynamic parameters simultaneously. It is not clear whether such approaches can lead to redundancies in the optimization problem. We deliberately restrict ourselves to a very precise determination of the center-of-mass (COM) and the mass of the individual rigid bodies. As a result, we do not use Persistent Exciting (PE) trajectories and perform the identification based on motion capture and force plate measurements of 172 static poses. This results in more accurate experimental data and allows a more precise update of static parameters by means of an optimization problem. The inertial parameters are not updated and have to be adjusted using classical approaches, but based on the already improved static parameters. We report the performance of optimization by comparing the distance of the ground-projected-center-of-mass (GCOM) against the measured GCOM from the model information of the original and optimized model for each static pose. The improvement of the optimized model is furthermore reflected by means of a recorded dynamic squat motion and by analyzing the residual torques and forces acting at the floating base of the robot. identification.
{"title":"Motion Capture Based Model Identification of the Humanoid Robot REEM-C Using Static Poses","authors":"Felix Aller, M. Harant, K. Mombaur","doi":"10.3311/eccomasmbd2021-233","DOIUrl":"https://doi.org/10.3311/eccomasmbd2021-233","url":null,"abstract":"In this paper, we describe an approach for the model identification of the humanoid robot REEM-C. In contrast to previous work, we do not attempt to determine all dynamic parameters simultaneously. It is not clear whether such approaches can lead to redundancies in the optimization problem. We deliberately restrict ourselves to a very precise determination of the center-of-mass (COM) and the mass of the individual rigid bodies. As a result, we do not use Persistent Exciting (PE) trajectories and perform the identification based on motion capture and force plate measurements of 172 static poses. This results in more accurate experimental data and allows a more precise update of static parameters by means of an optimization problem. The inertial parameters are not updated and have to be adjusted using classical approaches, but based on the already improved static parameters. We report the performance of optimization by comparing the distance of the ground-projected-center-of-mass (GCOM) against the measured GCOM from the model information of the original and optimized model for each static pose. The improvement of the optimized model is furthermore reflected by means of a recorded dynamic squat motion and by analyzing the residual torques and forces acting at the floating base of the robot. identification.","PeriodicalId":431921,"journal":{"name":"Proceedings of the 10th ECCOMAS Thematic Conference on MULTIBODY DYNAMICS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124386920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.3311/eccomasmbd2021-192
B. Boudon, Pierre Malafosse, Louis Guigon, R. Margetts, C. Bouzgarrou, T. Dang
This paper presents a bond graph model of the 3-CRS parallel robot and the associated simulations. The structural and modular approach proposed with bond graph permits the systematic modeling of mechatronic multibody systems. From a library of elements, the model is built as an assembly of components or modules (rigid bodies and kinematic joints) by following the structure of the actual system. The bond graph model of the robot consists of a multibody system (MBS) augmented with electrical actuators and controllers. Simulations have been conducted to test several kinematic configurations, dynamics scenarios and to evaluate robot performance.
{"title":"Simulation of the Dynamics of the 3-CRS Parallel Robot with a Bond Graph Approach","authors":"B. Boudon, Pierre Malafosse, Louis Guigon, R. Margetts, C. Bouzgarrou, T. Dang","doi":"10.3311/eccomasmbd2021-192","DOIUrl":"https://doi.org/10.3311/eccomasmbd2021-192","url":null,"abstract":"This paper presents a bond graph model of the 3-CRS parallel robot and the associated simulations. The structural and modular approach proposed with bond graph permits the systematic modeling of mechatronic multibody systems. From a library of elements, the model is built as an assembly of components or modules (rigid bodies and kinematic joints) by following the structure of the actual system. The bond graph model of the robot consists of a multibody system (MBS) augmented with electrical actuators and controllers. Simulations have been conducted to test several kinematic configurations, dynamics scenarios and to evaluate robot performance.","PeriodicalId":431921,"journal":{"name":"Proceedings of the 10th ECCOMAS Thematic Conference on MULTIBODY DYNAMICS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122821804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.3311/eccomasmbd2021-113
Simon Sailer, S. Eugster, R. Leine
The tippedisk is a new mechanical-mathematical archetype for friction induced insta-bility phenomena, showing an inversion similar to the inversion of the tippetop. Un-like the tippetop, the tippedisk has no rotational symmetry, which greatly complicates its analysis. Since the system cannot be reduced to a planar one, one has to consider the full three-dimensional kinematics, being intrinsically nonlinear. In this work a new minimal model is derived that contains the main relevant physical effects so that the inversion phenomenon can be described qualitatively. The in-depth analysis leads to slow-fast systems with homoclinic connections and global bifurcations.
tip - disk是研究摩擦不稳定现象的一种新的力学数学原型，它表现出类似于tip - top的反转。与陀螺不同的是，陀螺盘没有旋转对称性，这使分析变得非常复杂。由于系统不能简化为平面系统，必须考虑完整的三维运动学，本质上是非线性的。在这项工作中，导出了一个新的最小模型，其中包含了主要的相关物理效应，从而可以定性地描述反转现象。深入分析得到了具有同斜连接和全局分岔的慢速系统。
{"title":"The Tippedisk: A Minimal Model For Friction-Induced Inversion","authors":"Simon Sailer, S. Eugster, R. Leine","doi":"10.3311/eccomasmbd2021-113","DOIUrl":"https://doi.org/10.3311/eccomasmbd2021-113","url":null,"abstract":"The tippedisk is a new mechanical-mathematical archetype for friction induced insta-bility phenomena, showing an inversion similar to the inversion of the tippetop. Un-like the tippetop, the tippedisk has no rotational symmetry, which greatly complicates its analysis. Since the system cannot be reduced to a planar one, one has to consider the full three-dimensional kinematics, being intrinsically nonlinear. In this work a new minimal model is derived that contains the main relevant physical effects so that the inversion phenomenon can be described qualitatively. The in-depth analysis leads to slow-fast systems with homoclinic connections and global bifurcations.","PeriodicalId":431921,"journal":{"name":"Proceedings of the 10th ECCOMAS Thematic Conference on MULTIBODY DYNAMICS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122143041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.3311/eccomasmbd2021-156
Davide Manfredo, Vanessa Dörlich, J. Linn, M. Arnold
{"title":"First Steps in Data Based Constitutive Modelling of Inelastic Effects in Composite Cables Using Preisach Hysteresis Operators","authors":"Davide Manfredo, Vanessa Dörlich, J. Linn, M. Arnold","doi":"10.3311/eccomasmbd2021-156","DOIUrl":"https://doi.org/10.3311/eccomasmbd2021-156","url":null,"abstract":"","PeriodicalId":431921,"journal":{"name":"Proceedings of the 10th ECCOMAS Thematic Conference on MULTIBODY DYNAMICS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129472613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.3311/eccomasmbd2021-172
M. Ruggiu, F. González
When performing the numerical integration of multibody systems (MBS) dynamics, the analyst can choose from a wide variety of methods and implementations. Selecting the most appropriate option for a particular application is not a straightforward task; as a consequence, several benchmark examples have been formulated by the MBS research community with the intent to assess the accuracy and performance of different solution methods when applied to certain kinds of mechanical problems. This paper introduces a variation of the slider-crank mechanism, already employed as benchmark problem in the MBS literature, intended to evaluate the performance of variable-step MBS algorithms. Three cases, featuring singular configurations and variable-frequency external actions, were defined. The example is used to illustrate some necessary elements in the definition of a benchmark problem and in the process of comparing different solution methods, as well as difficulties that can arise during this task. The proposed example was used to evaluate the behaviour of a variable-step index-3 augmented Lagrangian algorithm with velocity and acceleration projections, as well as other well-known solution methods.
{"title":"Assessment of variable step-size integration of multibody systems","authors":"M. Ruggiu, F. González","doi":"10.3311/eccomasmbd2021-172","DOIUrl":"https://doi.org/10.3311/eccomasmbd2021-172","url":null,"abstract":"When performing the numerical integration of multibody systems (MBS) dynamics, the analyst can choose from a wide variety of methods and implementations. Selecting the most appropriate option for a particular application is not a straightforward task; as a consequence, several benchmark examples have been formulated by the MBS research community with the intent to assess the accuracy and performance of different solution methods when applied to certain kinds of mechanical problems. This paper introduces a variation of the slider-crank mechanism, already employed as benchmark problem in the MBS literature, intended to evaluate the performance of variable-step MBS algorithms. Three cases, featuring singular configurations and variable-frequency external actions, were defined. The example is used to illustrate some necessary elements in the definition of a benchmark problem and in the process of comparing different solution methods, as well as difficulties that can arise during this task. The proposed example was used to evaluate the behaviour of a variable-step index-3 augmented Lagrangian algorithm with velocity and acceleration projections, as well as other well-known solution methods.","PeriodicalId":431921,"journal":{"name":"Proceedings of the 10th ECCOMAS Thematic Conference on MULTIBODY DYNAMICS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129134899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.3311/eccomasmbd2021-181
P. Wasmer, P. Betsch
{"title":"Non-Linear Beam Formulation with NURBS Interpolation for the Simulation of Sliding Contacts","authors":"P. Wasmer, P. Betsch","doi":"10.3311/eccomasmbd2021-181","DOIUrl":"https://doi.org/10.3311/eccomasmbd2021-181","url":null,"abstract":"","PeriodicalId":431921,"journal":{"name":"Proceedings of the 10th ECCOMAS Thematic Conference on MULTIBODY DYNAMICS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124006386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.3311/eccomasmbd2021-138
Christian Zauner, H. Gattringer, A. Müller, Matthias Jörgl
Tracking sequences of predefined open and closed paths is of crucial interest for applications like laser cutting and similar production processes. These distinct paths are connected by non-productive, four times continuously differentiable trajectories, which also account for the overall process time. Heuristic methods are applied in order to find a proper sequencing of the open and closed path and thereby minimize the overall process time subject to constraints given by the system limits. To this end the exact traversing times of the non-productive linking trajectories are computed, which also have to be time optimal subject to the system limits. Finally two heuristic algorithms are presented and compared with respect to solution quality and calculation time using randomly generated problems.
{"title":"A Heuristic Sequencing Method for Time Optimal Tracking of Open and Closed Paths","authors":"Christian Zauner, H. Gattringer, A. Müller, Matthias Jörgl","doi":"10.3311/eccomasmbd2021-138","DOIUrl":"https://doi.org/10.3311/eccomasmbd2021-138","url":null,"abstract":"Tracking sequences of predefined open and closed paths is of crucial interest for applications like laser cutting and similar production processes. These distinct paths are connected by non-productive, four times continuously differentiable trajectories, which also account for the overall process time. Heuristic methods are applied in order to find a proper sequencing of the open and closed path and thereby minimize the overall process time subject to constraints given by the system limits. To this end the exact traversing times of the non-productive linking trajectories are computed, which also have to be time optimal subject to the system limits. Finally two heuristic algorithms are presented and compared with respect to solution quality and calculation time using randomly generated problems.","PeriodicalId":431921,"journal":{"name":"Proceedings of the 10th ECCOMAS Thematic Conference on MULTIBODY DYNAMICS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132193687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.3311/eccomasmbd2021-139
Valentin Dambly, H. Huynh, O. Verlinden, E. Rivière-Lorphèvre
Robotic machining is a fast-growing technology in the field of mechanical manufacturing. Indeed, it is generally accepted that for the same working space, a fully equipped robotic machining cell can cost 30 to 50 % less than a conventional machine tool. However, inaccuracies resulting either from vibrations or deflections occur while the robot is subjected to cutting forces, inherent to its flexible structure. As an order of magnitude, the stiffness at the tool-tip is about 1 N / µ m for industrial robots against more than 50 N / µ m for CNC machine tools. The flexibility source has been investi-gated and appears to be caused by the robot articulations in a proportion of 80% while the remaining flexibility issues from the structural elasticity. In order to improve the accuracy of robotic machining operations, several approaches have been carried out such as the study of stable cutting conditions and the online/offline compensation of the tool trajectory. Two aspects of the operation must be modeled, on the one hand the model of the cutting machine, being an industrial robot in robotic machining, and on the other hand, the machining model including the resulting geometry of the workpiece. A coupled model is then proposed with the multi-body model of the robot subjected to machining forces. The multi-body model includes the flexibility induced by the structure and the articulations. In order to compensate the deviations, a solution is proposed where the trajectory is discretized in nodes with a compensation taking the system dynamics into account by successive simulations of the operation. The algorithm involves two steps, firstly it aims to detect critical locations of the path and add or reposition nodes to reduce the deviation and secondly an optimization layer modifies nodes positions and velocities for a finer reduction. The method is deployed for three systems of increasing complexity for a face milling operation, showing a machining error reduction.
机器人加工是机械制造领域中发展迅速的一项技术。事实上，人们普遍认为，对于相同的工作空间，一个装备齐全的机器人加工单元的成本可以比传统机床低30%到50%。然而，当机器人受到其柔性结构固有的切削力时，由振动或偏转引起的不准确性会发生。作为一个数量级，工业机器人的刀尖刚度约为1 N /µm，而数控机床的刀尖刚度超过50 N /µm。柔性来源已被调查，似乎是由机器人的关节在80%的比例引起的，而其余的柔性问题来自结构弹性。为了提高机器人加工的精度，研究了稳定切削条件和刀具轨迹的在线/离线补偿等方法。操作的两个方面必须建模，一方面是切割机的模型，作为机器人加工中的工业机器人，另一方面是加工模型，包括得到的工件几何形状。在此基础上，建立了机器人在加工力作用下的多体耦合模型。多体模型包括由结构和关节引起的柔性。为了补偿这些偏差，提出了一种将轨迹离散在节点上的解决方案，并通过连续的操作模拟来考虑系统动力学的补偿。该算法包括两个步骤，首先是检测路径的关键位置并添加或重新定位节点以减少偏差，其次是优化层修改节点的位置和速度以进行更精细的减少。该方法应用于三个日益复杂的面铣削操作系统，显示加工误差减少。
{"title":"Coupled Multibody Model Of Industrial Robot With Milling Simulator For Trajectory Compensation","authors":"Valentin Dambly, H. Huynh, O. Verlinden, E. Rivière-Lorphèvre","doi":"10.3311/eccomasmbd2021-139","DOIUrl":"https://doi.org/10.3311/eccomasmbd2021-139","url":null,"abstract":"Robotic machining is a fast-growing technology in the field of mechanical manufacturing. Indeed, it is generally accepted that for the same working space, a fully equipped robotic machining cell can cost 30 to 50 % less than a conventional machine tool. However, inaccuracies resulting either from vibrations or deflections occur while the robot is subjected to cutting forces, inherent to its flexible structure. As an order of magnitude, the stiffness at the tool-tip is about 1 N / µ m for industrial robots against more than 50 N / µ m for CNC machine tools. The flexibility source has been investi-gated and appears to be caused by the robot articulations in a proportion of 80% while the remaining flexibility issues from the structural elasticity. In order to improve the accuracy of robotic machining operations, several approaches have been carried out such as the study of stable cutting conditions and the online/offline compensation of the tool trajectory. Two aspects of the operation must be modeled, on the one hand the model of the cutting machine, being an industrial robot in robotic machining, and on the other hand, the machining model including the resulting geometry of the workpiece. A coupled model is then proposed with the multi-body model of the robot subjected to machining forces. The multi-body model includes the flexibility induced by the structure and the articulations. In order to compensate the deviations, a solution is proposed where the trajectory is discretized in nodes with a compensation taking the system dynamics into account by successive simulations of the operation. The algorithm involves two steps, firstly it aims to detect critical locations of the path and add or reposition nodes to reduce the deviation and secondly an optimization layer modifies nodes positions and velocities for a finer reduction. The method is deployed for three systems of increasing complexity for a face milling operation, showing a machining error reduction.","PeriodicalId":431921,"journal":{"name":"Proceedings of the 10th ECCOMAS Thematic Conference on MULTIBODY DYNAMICS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125242254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.3311/eccomasmbd2021-112
Altay Zhakatayev, Yuri V. Rogovchenko, M. Pätzold
We investigate the effect of the choice of a set of generalized coordinates (GCs) on the simulation of the behavior of the dynamical system using the single-link spherical pendulum as an example. Specifically, we focus our attention on numerical errors and the simulation time necessary to simulate system dynamics. The Lagrangian method is applied to obtain the equations of motion. The generalized Euler angles are used as GCs. The GCs depend on the direction of the axes along which they are defined. Therefore, by parameterizing the directions of these two axes, different sets of GCs with the corresponding system of nonlinear differential equations are obtained. For a spherical pendulum, we demonstrate that the optimal sets of GCs leading to the minimum simulation time are orthogonal sets. However, contrary to our expectations, orthogonal sets do not result in the minimum simulation error. Additionally, the intrinsic generalized Euler angles lead to faster simulations than the extrinsic ones. Therefore, different choices of GCs are not equivalent from a numerical point of view and further research is needed to develop a strategy for selecting an optimal set of GCs.
{"title":"Influence of Generalized Coordinates on System Dynamics","authors":"Altay Zhakatayev, Yuri V. Rogovchenko, M. Pätzold","doi":"10.3311/eccomasmbd2021-112","DOIUrl":"https://doi.org/10.3311/eccomasmbd2021-112","url":null,"abstract":"We investigate the effect of the choice of a set of generalized coordinates (GCs) on the simulation of the behavior of the dynamical system using the single-link spherical pendulum as an example. Specifically, we focus our attention on numerical errors and the simulation time necessary to simulate system dynamics. The Lagrangian method is applied to obtain the equations of motion. The generalized Euler angles are used as GCs. The GCs depend on the direction of the axes along which they are defined. Therefore, by parameterizing the directions of these two axes, different sets of GCs with the corresponding system of nonlinear differential equations are obtained. For a spherical pendulum, we demonstrate that the optimal sets of GCs leading to the minimum simulation time are orthogonal sets. However, contrary to our expectations, orthogonal sets do not result in the minimum simulation error. Additionally, the intrinsic generalized Euler angles lead to faster simulations than the extrinsic ones. Therefore, different choices of GCs are not equivalent from a numerical point of view and further research is needed to develop a strategy for selecting an optimal set of GCs.","PeriodicalId":431921,"journal":{"name":"Proceedings of the 10th ECCOMAS Thematic Conference on MULTIBODY DYNAMICS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129943148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1900-01-01DOI: 10.3311/eccomasmbd2021-121
Lennart Frie, O. Dieterich, P. Eberhard
The dynamical behavior of Elastic Multibody Systems (EMBS) is often analyzed using virtual prototypes described by high-dimensional systems of differential equations. Model Order Reduction (MOR) is a key step to permit efficient system evaluations by approximating the full system with a reduced order surrogate model. It is one challenge in MOR of EMBS, to describe the dynamics induced through the coupling of bodies in the reduced system. In this contribution, a workflow for the reduction of EMBS with fast rotating bodies is presented. The rotation causes a change of dynamical behavior due to inertia forces and, therefore, cannot be neglected. In the scope of this work a linear description of rotating bodies with constant angular velocity is given. Different projection-based MOR techniques are compared and applied to an industrial model of a helicopter with rotating rotor. For this purpose, a short introduction on modeling of EMBS and MOR is given. Substructured reduction is then contrasted to the reduction of the coupled system for modal reduction techniques, moment matching based on Krylov subspaces, and Proper Orthogonal Decomposition. The approximation errors of the reduced systems are compared in frequency domain. It is shown that rotation-dependent terms are essential to describe the dynamic behavior of the system correctly. Reduced models with low approximation errors and large speed-up are obtained with substructured Proper Orthogonal Decomposition and outperform the standard techniques modal truncation and Craig-Bampton reduction.
{"title":"Model Order Reduction for Elastic Multibody Systems with Fast Rotating Flexible Bodies","authors":"Lennart Frie, O. Dieterich, P. Eberhard","doi":"10.3311/eccomasmbd2021-121","DOIUrl":"https://doi.org/10.3311/eccomasmbd2021-121","url":null,"abstract":"The dynamical behavior of Elastic Multibody Systems (EMBS) is often analyzed using virtual prototypes described by high-dimensional systems of differential equations. Model Order Reduction (MOR) is a key step to permit efficient system evaluations by approximating the full system with a reduced order surrogate model. It is one challenge in MOR of EMBS, to describe the dynamics induced through the coupling of bodies in the reduced system. In this contribution, a workflow for the reduction of EMBS with fast rotating bodies is presented. The rotation causes a change of dynamical behavior due to inertia forces and, therefore, cannot be neglected. In the scope of this work a linear description of rotating bodies with constant angular velocity is given. Different projection-based MOR techniques are compared and applied to an industrial model of a helicopter with rotating rotor. For this purpose, a short introduction on modeling of EMBS and MOR is given. Substructured reduction is then contrasted to the reduction of the coupled system for modal reduction techniques, moment matching based on Krylov subspaces, and Proper Orthogonal Decomposition. The approximation errors of the reduced systems are compared in frequency domain. It is shown that rotation-dependent terms are essential to describe the dynamic behavior of the system correctly. Reduced models with low approximation errors and large speed-up are obtained with substructured Proper Orthogonal Decomposition and outperform the standard techniques modal truncation and Craig-Bampton reduction.","PeriodicalId":431921,"journal":{"name":"Proceedings of the 10th ECCOMAS Thematic Conference on MULTIBODY DYNAMICS","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115266783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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