Journal of Computational and Nonlinear Dynamics最新文献_第10页

Variational Principles for the Trajectory Tracking Control of Underactuated Mechanical Systems 欠驱动机械系统轨迹跟踪控制的变分原理

IF 2 4区工程技术

Journal of Computational and Nonlinear Dynamics Pub Date : 2023-01-03 DOI: 10.1115/1.4056593

Bálint Bodor, L. Bencsik

{"title":"Variational Principles for the Trajectory Tracking Control of Underactuated Mechanical Systems","authors":"Bálint Bodor, L. Bencsik","doi":"10.1115/1.4056593","DOIUrl":"https://doi.org/10.1115/1.4056593","url":null,"abstract":"\u0000 Robotics is undergoing dynamic progression with the spread of soft robots and compliant mechanisms. The mechanical models describing these systems are underactuated, having more degrees of freedom than inputs. The trajectory tracking control of underactuated systems is not straightforward. The solution of the inverse dynamics is not stable in all cases, as it only considers the actual state of the system. Therefore employing the advances of optimal control theory is a reasonable choice. However, the real-time application of these is challenging as the solution to the discretized optimization problems is numerically expensive.\u0000 This paper presents a novel iterative approach to solving nonlinear optimal control problems. The authors first define the iteration formula after which the obtained equations are discretized to prepare the numerical solution, contrarily to the accessible works in the literature having reverse order. The main idea is to approximate the cost functional with a second-order expansion in each iteration step, which is then extremized to get the subsequent approximation of the optimum. In the case of nonlinear optimal control problems, the process leads to a sequence of time-variant LQR problems. The proposed technique was effectively applied to the trajectory tracking control of a flexible RR manipulator. The case study showed that the initialization of the iteration is simple, and the convergence is rapid.","PeriodicalId":54858,"journal":{"name":"Journal of Computational and Nonlinear Dynamics","volume":"12 19 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78725127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

Stability Analysis of Nonlinear Rotating Systems Using Lyapunov Characteristic Exponents Estimated From Multibody Dynamics 基于多体动力学估计的Lyapunov特征指数的非线性旋转系统稳定性分析

IF 2 4区工程技术

Journal of Computational and Nonlinear Dynamics Pub Date : 2023-01-03 DOI: 10.1115/1.4056591

G. Cassoni, A. Zanoni, A. Tamer, P. Masarati

引用次数: 0

Beams with A Varying Cross Section in the Generalized Strain Formulation for Flexure Modelling 变截面梁挠曲模型的广义应变公式

IF 2 4区工程技术

Journal of Computational and Nonlinear Dynamics Pub Date : 2022-12-16 DOI: 10.1115/1.4056482

K. Dwarshuis, R. Aarts, M. Ellenbroek, D. Brouwer

{"title":"Beams with A Varying Cross Section in the Generalized Strain Formulation for Flexure Modelling","authors":"K. Dwarshuis, R. Aarts, M. Ellenbroek, D. Brouwer","doi":"10.1115/1.4056482","DOIUrl":"https://doi.org/10.1115/1.4056482","url":null,"abstract":"\u0000 Flexure joints are rapidly gaining ground in precision engineering because of their predictable behavior. However their range of motion is limited due to a stress limitation and a loss of support stiffness in deformed configurations. The support stiffness can be significantly increased by using leafsprings of which the width and thickness vary over the length of the leafspring. This paper presents formulations for two beam elements with a varying cross section that can be used for the efficient modelling of these types of leafsprings. One of these beam-formulations includes the modelling of the warping due to torsion, which is shown to be essential for accurate modelling. The 90% accuracy in stiffness results and 80% accuracy in stress results, in comparison with results of finite element analyses, are sufficient for the evaluation of concept-designs. Optimizations shows that the support stiffness of two typical flexure joints can be increased by a factor of up to 4.0 keeping the same range of motion, by allowing the cross section to vary over the length of the leafspring. In these two flexure joints, 98% of this improvement can already be obtained by only varying the thickness, keeping a constant width.","PeriodicalId":54858,"journal":{"name":"Journal of Computational and Nonlinear Dynamics","volume":"5 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82332394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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

Nonlinear Agent-Based Dynamics: Which Metric Mitigates Polarization? 非线性智能体动力学:哪个度量可以减轻极化?

IF 2 4区工程技术

Journal of Computational and Nonlinear Dynamics Pub Date : 2022-12-16 DOI: 10.1115/1.4056481

Bodo Herzog

引用次数: 1

Finite-time Synchronization of Fractional-order Energy Resources Demand-Supply Hyperchaotic Systems via Fractional-order Prediction-based Feedback Control Strategy with Bio-inspired Multiobjective Optimization 基于生物多目标优化的分数阶预测反馈控制策略的分数阶能源供需超混沌系统有限时间同步

IF 2 4区工程技术

Journal of Computational and Nonlinear Dynamics Pub Date : 2022-12-13 DOI: 10.1115/1.4056462

A. Soukkou, Y. Soukkou, S. Haddad, M. Benghanem, A. Rabhi

{"title":"Finite-time Synchronization of Fractional-order Energy Resources Demand-Supply Hyperchaotic Systems via Fractional-order Prediction-based Feedback Control Strategy with Bio-inspired Multiobjective Optimization","authors":"A. Soukkou, Y. Soukkou, S. Haddad, M. Benghanem, A. Rabhi","doi":"10.1115/1.4056462","DOIUrl":"https://doi.org/10.1115/1.4056462","url":null,"abstract":"\u0000 The concept of fractional-order control (F-oC) is exploited in this paper to synchronize fractional-order dynamical systems. The addressed systems in this paper reflect the real physical phenomena characterized by the complicated relationship between supply and demand for energy resources in the Shanghai area. Thus, we provide the developed fractional energy resource attractor and the simulation results regarding synchronization under the proposed control law of the same fractional energy resource attractor. Note that most of the synchronization methods achieved excellent performance when dealing with complex continuous systems; however, no method addressed the synchronization problem of fractional-order energy resource systems based on the F-oC and modern optimization techniques, to the best of our knowledge. By designing the finite-time control theory, the finite-time full synchronization of two identical fractional-order energy resources demand-supply hyperchaotic systems (F-oERDSHSs) is investigated due to its performance. The advanced prediction-based fractional-order control law (Pb-FoCL) is established for finite-time synchronization of F-oERDSHSs. The design procedure becomes a multiobjective optimization problem of the knowledge base of the developed controller while satisfying the desired performance requirements. The Finite-Time Stability (F-TS) of the control-loop system is proved by using the finite-time Lyapunov stability theory. Furthermore, the Improved Artificial Hummingbird Algorithm (I-AHA) is used to find an optimal knowledge base of Pb-FoCL while achieving the design constraints. Simulation results are provided to verify the efficiency of the proposed control strategy.","PeriodicalId":54858,"journal":{"name":"Journal of Computational and Nonlinear Dynamics","volume":"22 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2022-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73211885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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: 2

Constrained Large-Displacement Thermal Analysis 约束大位移热分析

IF 2 4区工程技术

Journal of Computational and Nonlinear Dynamics Pub Date : 2022-12-12 DOI: 10.1115/1.4056182

A. Shabana, Mahmoud Elbakly, Dayu Zhang

{"title":"Constrained Large-Displacement Thermal Analysis","authors":"A. Shabana, Mahmoud Elbakly, Dayu Zhang","doi":"10.1115/1.4056182","DOIUrl":"https://doi.org/10.1115/1.4056182","url":null,"abstract":"\u0000 Two different cases are encountered in the thermal analysis of solids. In the first case, continua are not subject to boundary and motion constraints and all material points experience same displacement-gradient changes as the result of application of thermal loads. In this case, referred to as unconstrained thermal expansion, the thermal load produces uniform stress-free motion within the continuum. In the second case, point displacements due to boundary and motion constraints are restricted, and therefore, continuum points do not move freely when thermal loads are applied. This second case, referred to as constrained thermal expansion, leads to thermal stresses and its study requires proper identification of the independent coordinates which represent expansion degrees-of-freedom. To have objective evaluation and comparison between the two cases of constrained and unconstrained thermal expansion, the reference-configuration geometry is accurately described using the absolute nodal coordinate formulation (ANCF) finite elements. ANCF position-gradient vectors have unique geometric meanings as tangent to coordinate lines, allowing systematic description of the two different cases of unconstrained and constrained thermal expansions using multiplicative decomposition of the matrix of position-gradient vectors. Furthermore, generality of the approach for large-displacement thermal analysis requires using the Lagrange–D'Alembert principle for proper treatment of algebraic constraint equations. Numerical results are presented to compare two different expansion cases, demonstrate use of the new approach, and verify its results by comparing with conventional finite element (FE) approaches.","PeriodicalId":54858,"journal":{"name":"Journal of Computational and Nonlinear Dynamics","volume":"64 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2022-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81090704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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: 3

The Homotopy Analysis Method for Solving Differential Equations with Generalized Caputo-Type Fractional Derivatives 广义caputo型分数阶导数微分方程的同伦分析方法

IF 2 4区工程技术

Journal of Computational and Nonlinear Dynamics Pub Date : 2022-12-04 DOI: 10.1115/1.4056392

Wafia Fafa, Z. Odibat, N. Shawagfeh

引用次数: 1

Effective Optimized Decomposition Algorithms for Solving Nonlinear Fractional Differential Equations 求解非线性分数阶微分方程的有效优化分解算法

IF 2 4区工程技术

Journal of Computational and Nonlinear Dynamics Pub Date : 2022-11-23 DOI: 10.1115/1.4056254

Marwa Laoubi, Z. Odibat, B. Maayah

引用次数: 2

On the Periodicity of the Rational Dynamical System Corresponding to the Vannimenus–Ising Model

IF 2 4区工程技术

Journal of Computational and Nonlinear Dynamics Pub Date : 2022-11-17 DOI: 10.1115/1.4056133

H. Akın

引用次数: 4

Construction of Friction Model of the Third Body Layer and Its Effects on the Dynamic Characteristics in Brake System 第三体层摩擦模型的建立及其对制动系统动态特性的影响

IF 2 4区工程技术

Journal of Computational and Nonlinear Dynamics Pub Date : 2022-11-17 DOI: 10.1115/1.4056181

Yuhang Zhang, Daogao Wei, Bofu Wu, Ping Jiang

引用次数: 0