Modeling the vibration of spatial flexible mechanisms through an equivalent rigid-link system/component mode synthesis approach

Vidoni, Renato; Gallina, Paolo; Boscariol, Paolo; Gasparetto, Alessandro; Giovagnoni, Marco

doi:10.1177/1077546315604495

Cited by 16 publications

(7 citation statements)

References 40 publications

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“…Another possibility for describing multibody systems is with ordinary differential equation (ODE) formulations. The equivalent rigid link system (ERLS) [146][147][148] is an example of such a formulation for flexible multibody systems where the equations of motion are formulated on a system level without explicit kinematic constraints. With this approach, the overall motion of a mechanism is decomposed into the rigid body motion superimposed with elastic deformation.…”

Section: Flexible Multibody Formulationsmentioning

confidence: 99%

A review of flexible multibody dynamics for gradient-based design optimization

2021

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Design optimization of flexible multibody dynamics is critical to reducing weight and therefore increasing efficiency and lowering costs of mechanical systems. Simulation of flexible multibody systems, though, typically requires high computational effort which limits the usage of design optimization, especially when gradient-free methods are used and thousands of system evaluations are required. Efficient design optimization of flexible multibody dynamics is enabled by gradient-based optimization methods in concert with analytical sensitivity analysis. The present study summarizes different formulations of the equations of motion of flexible multibody dynamics. Design optimization techniques are introduced, and applications to flexible multibody dynamics are categorized. Efficient sensitivity analysis is the centerpiece of gradient-based design optimization, and sensitivity methods are introduced. The increased implementation effort of analytical sensitivity analysis is rewarded with high computational efficiency. An exemplary solution strategy for system and sensitivity evaluations is shown with the analytical direct differentiation method. Extensive literature sources are shown related to recent research activities.

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Section: Flexible Multibody Formulationsmentioning

confidence: 99%

A review of flexible multibody dynamics for gradient-based design optimization

2021

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“…The same dynamic model has been validated and used in several works, such as in [30] for the development of predictive control strategies for position control and vibration damping, and in [31] for the development of state observers for flexible-link mechanisms. Recently, such model has also been extended to 3D mechanisms in [32][33][34]. The dynamic model of flexible-link planar mechanisms is based on an Equivalent Rigid-Link System (ERLS) formulation, and on the use of a discretization based on the finite element method (FEM).…”

Section: Dynamic Model Of Multibody Flexible-link Mechanismsmentioning

confidence: 99%

Nonlinear Control of Multibody Flexible Mechanisms: A Model-Free Approach

2021

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In this paper a novel nonlinear controller for position and vibration control of flexible-link mechanisms is introduced. The proposed control strategy is model-free and does not require the measurement of the elastic deformation of the mechanism, since the control relies only on the knowledge of the angular position of the actuator and on its time derivative, which can be measured simply with a quadrature encoder. The conditions for the closed-loop stability are evaluated using Lyapunov theory. The performance of the proposed technique is evaluated on a four-bar flexible-link mechanism. Superior vibration damping and more accurate trajectory tracking is obtained in comparison with a PD controller and a fractional order controller, which relies on the same set of measurement as the proposed nonlinear controller.

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“…where the dimension of x, denoted as n, is the number of degrees of freedom (dofs) of the full-order model. e system model is given by the following set of nonlinear ODEs [23]:…”

Section: Modelingmentioning

confidence: 99%

“…e typical implementation of the aforementioned CB method for reducing FLMB systems exploits the component mode synthesis strategy [21]. Basically, the linear FE models of all the links are generated and reduced and, then, they are embedded in a moving frame [23] or in a corotational frame [24], to represent large displacements of the mechanism. Such a component-level reduction strategy might negatively affect the reduced model correctness since it does not fully account for modal characteristic changes due to the motion of the multibody system.…”

Section: Introductionmentioning

confidence: 99%

Reduced‐Order Observers for Nonlinear State Estimation in Flexible Multibody Systems

Palomba

Richiedei

Trevisani

2018

Shock and Vibration

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Modern control schemes adopted in multibody systems take advantage of the knowledge of a large set of measurements of the most important state variables to improve system performances. In the case of flexible-link multibody systems, however, the direct measurement of these state variables is not usually possible or convenient. Hence, it is necessary to estimate them through accurate models and a reduced set of measurements ensuring observability. In order to cope with the large dimension of models adopted for flexible multibody systems, this paper exploits model reduction for synthesizing reduced-order nonlinear state observers. Model reduction is done through a modified Craig-Bampton strategy that handles effectively nonlinearities due to large displacements of the mechanism and through a wise selection of the most important coordinates to be retained in the model. Starting from such a reduced nonlinear model, a nonlinear state observer is developed through the extended Kalman filter (EKF). The method is applied to the numerical test case of a six-bar planar mechanism. The smaller size of the model, compared with the original one, preserves accuracy of the estimates while reducing the computational effort.

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Modeling the vibration of spatial flexible mechanisms through an equivalent rigid-link system/component mode synthesis approach

Cited by 16 publications

References 40 publications

A review of flexible multibody dynamics for gradient-based design optimization

A review of flexible multibody dynamics for gradient-based design optimization

Nonlinear Control of Multibody Flexible Mechanisms: A Model-Free Approach

Reduced‐Order Observers for Nonlinear State Estimation in Flexible Multibody Systems

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