Multibody System Dynamics最新文献_第3页

Simulation and parameterization of nonlinear elastic behavior of cables 电缆非线性弹性行为的模拟和参数化

IF 3.4 2区工程技术

Multibody System Dynamics Pub Date : 2024-07-22 DOI: 10.1007/s11044-024-10008-2

Tian Zhao, Fabio Schneider-Jung, Joachim Linn, Ralf Müller

{"title":"Simulation and parameterization of nonlinear elastic behavior of cables","authors":"Tian Zhao, Fabio Schneider-Jung, Joachim Linn, Ralf Müller","doi":"10.1007/s11044-024-10008-2","DOIUrl":"https://doi.org/10.1007/s11044-024-10008-2","url":null,"abstract":"This work contributes to the simulation, modeling, and characterization of nonlinear elastic bending behavior within the framework of geometrically nonlinear rod models. These models often assume a linear constitutive bending behavior, which is not sufficient for some complex flexible slender structures. In general, nonlinear elastic behavior often coexists with inelastic behavior. In this work, we incorporate the inelastic deformation into the rod model using reference curvatures. We present an algorithmic approach for simulating the nonlinear elastic bending behavior, which is based on the theory of Cosserat rods, where the static equilibrium is calculated by minimizing the linear elastic energy. For this algorithmic approach, in each iteration the static equilibrium is obtained by minimizing the potential energy with locally constant algorithmic bending stiffness values. These constants are updated according to the given nonlinear elastic constitutive law until the state of the rod converges. To determine the nonlinear elastic constitutive bending behavior of the flexible slender structures (such as cables) from the measured values, we formulate an inverse problem. By solving it we aim to determine a curvature-dependent bending stiffness characteristic and the reference curvatures using the given measured values. We first provide examples using virtual bending measurements, followed by the application of bending measurements on real cables. Solving the inverse problem yields physically plausible results.","PeriodicalId":49792,"journal":{"name":"Multibody System Dynamics","volume":"43 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141745705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Predicting sit-to-stand motions with a deep reinforcement learning based controller under idealized exoskeleton assistance 用基于深度强化学习的控制器预测理想化外骨骼辅助下的坐立运动

IF 3.4 2区工程技术

Multibody System Dynamics Pub Date : 2024-07-22 DOI: 10.1007/s11044-024-10009-1

Neethan Ratnakumar, Kübra Akbaş, Rachel Jones, Zihang You, Xianlian Zhou

{"title":"Predicting sit-to-stand motions with a deep reinforcement learning based controller under idealized exoskeleton assistance","authors":"Neethan Ratnakumar, Kübra Akbaş, Rachel Jones, Zihang You, Xianlian Zhou","doi":"10.1007/s11044-024-10009-1","DOIUrl":"https://doi.org/10.1007/s11044-024-10009-1","url":null,"abstract":"Maintaining the capacity for sit-to-stand transitions is paramount for preserving functional independence and overall mobility in older adults and individuals with musculoskeletal conditions. Lower limb exoskeletons have the potential to play a significant role in supporting this crucial ability. In this investigation, a deep reinforcement learning (DRL) based sit-to-stand (STS) controller is developed to study the biomechanics of STS under both exoskeleton assisted and unassisted scenarios. Three distinct conditions are explored: 1) Hip joint assistance (H-Exo), 2) Knee joint assistance (K-Exo), and 3) Hip-knee joint assistance (H+K-Exo). By utilizing a generic musculoskeletal model, the STS joint trajectories generated under these scenarios align with unassisted experimental observations. We observe substantial reductions in muscle activations during the STS cycle, with an average decrease of 68.63% and 73.23% in the primary hip extensor (gluteus maximus) and primary knee extensor (vasti) muscle activations, respectively, under H+K-Exo assistance compared to the unassisted STS scenario. However, the H-Exo and K-Exo scenarios reveal unexpected increases in muscle activations in the hamstring and gastrocnemius muscles, potentially indicating a compensatory mechanism for stability. In contrast, the combined H+K-Exo assistance demonstrates a noticeable reduction in the activation of these muscles. These findings underscore the potential of sit-to-stand assistance, particularly in the combined hip-knee exoskeleton scenario, and contribute valuable insights for the development of robust DRL-based controllers for assistive devices to improve functional outcomes.","PeriodicalId":49792,"journal":{"name":"Multibody System Dynamics","volume":"53 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The implicit inversion method for calculating the forward dynamics input Jacobian 计算前向动力学输入雅各布的隐式反演法

IF 3.4 2区工程技术

Multibody System Dynamics Pub Date : 2024-07-22 DOI: 10.1007/s11044-024-10010-8

Gabriel Krög, Hubert Gattringer, Andreas Müller

{"title":"The implicit inversion method for calculating the forward dynamics input Jacobian","authors":"Gabriel Krög, Hubert Gattringer, Andreas Müller","doi":"10.1007/s11044-024-10010-8","DOIUrl":"https://doi.org/10.1007/s11044-024-10010-8","url":null,"abstract":"This paper presents the implicit inversion method (IIM), a recursive method to evaluate the Jacobian of the forward dynamics w.r.t. the system inputs, using intermediate results obtained from an O(n) forward dynamics algorithm. The resulting coefficient matrix, called the inertia-weighted input matrix (IWIM), can be used to significantly improve the performance of solving optimal control problems that take into account system dynamics for only the current time step. As the relationship between inputs and accelerations appears fixed within a time step, this matrix can be evaluated in the initialization step of the optimization. This means that the forward dynamics only needs to be solved once at the initialization of the optimization, rather than having to solve the equations in every iteration of the optimization. The method presented in this paper especially targets a case where the forward dynamics are calculated using an O(n) method and takes advantage of variables that are already known through the evaluation of that method. These quantities allow us to obtain the inertia-weighted input matrix without having to convert the system to its generalized coordinate form. Exploiting the shape of the resulting equation, it is even possible to avoid an explicit inversion of any matrices in the process. Finally, runtime comparisons between three different methods to calculate the IWIM are made for several examples.","PeriodicalId":49792,"journal":{"name":"Multibody System Dynamics","volume":"19 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141776133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An improved Udwadia–Kalaba approach for controller design in underactuated mechanical systems 用于欠驱动机械系统控制器设计的改进型 Udwadia-Kalaba 方法

IF 3.4 2区工程技术

Multibody System Dynamics Pub Date : 2024-07-19 DOI: 10.1007/s11044-024-10004-6

Xiang Wu, Xiaowei Li, Zhihui Li, Dan Zhang, Zhonghua Miao, Jin Zhou

{"title":"An improved Udwadia–Kalaba approach for controller design in underactuated mechanical systems","authors":"Xiang Wu, Xiaowei Li, Zhihui Li, Dan Zhang, Zhonghua Miao, Jin Zhou","doi":"10.1007/s11044-024-10004-6","DOIUrl":"https://doi.org/10.1007/s11044-024-10004-6","url":null,"abstract":"This paper further develops the Udwadia–Kalaba-approach-based view for the study of the controller design of underactuated systems. A challenge issue of the controller design for such complex systems is to implement an effective control input due to the non-full-rank feature of the control force configuration space. It becomes more difficult especially for the situation in which the control constraints are, in general, incompatible with the modeling constraints. In this paper, the modeling constraints are further divided into the natural and underactuated constraints, which can well capture the proper physical descriptions of underactuated systems. The control input that minimizes the control error and cost function can be derived by matrix operations, and then an additional constraint will be designed fully to address the incompatibility between the modeling and control constraints. This allowed us to develop an approach with precise effectiveness, high stability, and good robustness, which is applicable for various typical cases of complex underactuated systems. Finally, several representative numerical examples, including the fixed-point stabilization and trajectory tracking of a mobile robot, and the trajectory tracking of a hovercraft, are presented to demonstrate the proposed method.","PeriodicalId":49792,"journal":{"name":"Multibody System Dynamics","volume":"13 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141737517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Examining the simulation-to-reality gap of a wheel loader digging in deformable terrain 检验轮式装载机在可变形地形中挖掘的模拟与现实之间的差距

IF 3.4 2区工程技术

Multibody System Dynamics Pub Date : 2024-07-19 DOI: 10.1007/s11044-024-10005-5

Koji Aoshima, Martin Servin

引用次数: 0

A series of locking-free beam element models in absolute nodal coordinate formulation 绝对节点坐标法中的一系列无锁定梁元素模型

IF 3.4 2区工程技术

Multibody System Dynamics Pub Date : 2024-07-19 DOI: 10.1007/s11044-024-10006-4

Maosheng Zheng, Mingbo Tong, Jianping Chen, Fu Liu, Xiong Pan

{"title":"A series of locking-free beam element models in absolute nodal coordinate formulation","authors":"Maosheng Zheng, Mingbo Tong, Jianping Chen, Fu Liu, Xiong Pan","doi":"10.1007/s11044-024-10006-4","DOIUrl":"https://doi.org/10.1007/s11044-024-10006-4","url":null,"abstract":"To alleviate the locking problem in the ANCF beam elements, sufficient transverse gradient vectors are incorporated in the cross section to enrich the distribution of transverse strain along the cross section of the beam. Building upon this novel concept, this paper utilizes Pascal trigonometric polynomial to determine the position interpolation field of beam elements, and the distribution of transverse gradient vectors along the beam section is clarified through the collocation of boundary points and Chebyshev interpolation nodes, and then a series of locking-free beam models, based on the absolute nodal coordinate formulation, are developed. Additionally, it reveals the inherent mechanical mechanism of higher-order beam models in alleviating locking through strict mathematical analysis. Furthermore, to demonstrate the effectiveness of the new elements, six numerical simulation examples are designed, namely, three static examples and three dynamic examples, which involve small deformation statics, large deformation statics, small-scale elastic deformation, large-scale elastic deformation problems. Finally, the simulation results of the first four order beam models, Patel–Shabana model, and ECM approach are compared and analyzed in detail. The results indicate that the proposed higher-order beam models have high accuracy and can effectively eliminate the unnecessary influence caused by locking in complex mechanical problems, involving statics and dynamics problems.","PeriodicalId":49792,"journal":{"name":"Multibody System Dynamics","volume":"3 Suppl 1 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141737460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Conserving integration of multibody systems with singular and non-constant mass matrix including quaternion-based rigid body dynamics 具有奇异和非恒定质量矩阵的多体系统的守恒整合，包括基于四元数的刚体动力学

IF 3.4 2区工程技术

Multibody System Dynamics Pub Date : 2024-06-27 DOI: 10.1007/s11044-024-10001-9

Philipp L. Kinon, Peter Betsch

{"title":"Conserving integration of multibody systems with singular and non-constant mass matrix including quaternion-based rigid body dynamics","authors":"Philipp L. Kinon, Peter Betsch","doi":"10.1007/s11044-024-10001-9","DOIUrl":"https://doi.org/10.1007/s11044-024-10001-9","url":null,"abstract":"Mechanical systems with singular and/or configuration-dependent mass matrix can pose difficulties to Hamiltonian formulations, which are the standard choice for the design of energy-momentum conserving time integrators. In this work, we derive a structure-preserving time integrator for constrained mechanical systems based on a mixed variational approach. Livens’ principle (or sometimes called Hamilton–Pontryagin principle) features independent velocity and momentum quantities and circumvents the need to invert the mass matrix. In particular, we take up the description of rigid body rotations using unit quaternions. Using Livens’ principle, a new and comparatively easy approach to the simulation of these problems is presented. The equations of motion are approximated by using (partitioned) midpoint discrete gradients, thus generating a new energy-momentum conserving integration scheme for mechanical systems with singular and/or configuration-dependent mass matrix. The derived method is second-order accurate and algorithmically preserves a generalized energy function as well as the holonomic constraints and momentum maps corresponding to symmetries of the system. We study the numerical performance of the newly devised scheme in representative examples for multibody and rigid body dynamics.","PeriodicalId":49792,"journal":{"name":"Multibody System Dynamics","volume":"30 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141528984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Local coordinates on Lie groups for half-explicit time integration of Cosserat-rod models with constraints 有约束条件的 Cosserat-rod 模型半显式时间积分的李群局部坐标

IF 3.4 2区工程技术

Multibody System Dynamics Pub Date : 2024-06-20 DOI: 10.1007/s11044-024-10002-8

Denise Tumiotto, Martin Arnold

引用次数: 0

Quaternion-based finite-element computation of nonlinear modes and frequency responses of geometrically exact beam structures in three dimensions 基于四元数的三维几何精确梁结构非线性模态和频率响应有限元计算

IF 3.4 2区工程技术

Multibody System Dynamics Pub Date : 2024-06-19 DOI: 10.1007/s11044-024-09999-9

Marielle Debeurre, Aurélien Grolet, Olivier Thomas

{"title":"Quaternion-based finite-element computation of nonlinear modes and frequency responses of geometrically exact beam structures in three dimensions","authors":"Marielle Debeurre, Aurélien Grolet, Olivier Thomas","doi":"10.1007/s11044-024-09999-9","DOIUrl":"https://doi.org/10.1007/s11044-024-09999-9","url":null,"abstract":"In this paper, a novel method for computing the nonlinear dynamics of highly flexible slender structures in three dimensions (3D) is proposed. It is the extension to 3D of a previous work restricted to inplane (2D) deformations. It is based on the geometrically exact beam model, which is discretized with a finite-element method and solved entirely in the frequency domain with a harmonic balance method (HBM) coupled to an asymptotic numerical method (ANM) for continuation of periodic solutions. An important consideration is the parametrization of the rotations of the beam’s cross sections, much more demanding than in the 2D case. Here, the rotations are parametrized with quaternions, with the advantage of leading naturally to polynomial nonlinearities in the model, well suited for applying the ANM. Because of the HBM–ANM framework, this numerical strategy is capable of computing both the frequency response of the structure under periodic oscillations and its nonlinear modes (namely its backbone curves and deformed shapes in free conservative oscillations). To illustrate and validate this strategy, it is used to solve two 3D deformations test cases of the literature: a cantilever beam and a clamped–clamped beam subjected to one-to-one (1:1) internal resonance between two companion bending modes in the case of a nearly square cross section.","PeriodicalId":49792,"journal":{"name":"Multibody System Dynamics","volume":"58 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Rope–sheave contact transient analysis in hoisting operations with a bristle model and an arbitrary Lagrangian–Eulerian approach 用鬃毛模型和任意拉格朗日-欧勒方法对提升作业中的绳索-滑轮接触进行瞬态分析

IF 3.4 2区工程技术

Multibody System Dynamics Pub Date : 2024-06-18 DOI: 10.1007/s11044-024-10000-w

José L. Escalona

{"title":"Rope–sheave contact transient analysis in hoisting operations with a bristle model and an arbitrary Lagrangian–Eulerian approach","authors":"José L. Escalona","doi":"10.1007/s11044-024-10000-w","DOIUrl":"https://doi.org/10.1007/s11044-024-10000-w","url":null,"abstract":"This paper describes the development of a computational model for the rope–sheave contact interaction in reeving systems when the ropes are modeled with an arbitrary Lagrangian–Eulerian approach. This discretization approach has been developed in previous publications as a general and systematic method for the modeling and simulation of reeving systems. However, the rope–sheave contact model was avoided assuming the no-slip contact condition. The contact model developed in this paper introduces specialized ALE-ANCF-cubic rope contact elements that are used to discretize the rope segment winded at the sheave. The contact is modeled using a set of virtual discrete bristles attached to material points in the mid-line of the rope in one end and in contact with the sheave in the other end. Therefore, a second Lagrangian mesh, apart of the ALE mesh used to discretize the rope, is used to define the fixed ends of the bristles. The kinematics and dynamics used to calculate the normal and tangential contact forces are described in detail. The contact model is 3D and can be used to analyze the contact with a sheave groove with arbitrary shape. The tangential contact force model can be used to describe stick and slip contact conditions and, to improve the simulation performance of the model, an LuGre regularization tangential contact force model is used. The rope-sheave contact model is used to analyze the behavior of a simple elevator system. The numerical results show that the static rope-sheave contact interaction agrees well with an analytical solution of the problem. Finally, the same elevator system is analyzed dynamically for a cabin ride of 8 meters with a steady velocity of 1 m/s. Results show that the normal and tangential contact forces during the steady velocity period are not so different from the static solution, but very different from the classical Creep Theory and Firbank’s Theory.","PeriodicalId":49792,"journal":{"name":"Multibody System Dynamics","volume":"75 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0