Model updating in flexible-link multibody systems

Belotti, Roberto; Caneva, G; Palomba, Ilaria; Richiedei, Dario; Trevisani, Alberto

doi:10.1088/1742-6596/744/1/012073

Cited by 5 publications

(7 citation statements)

References 8 publications

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“…e results provided by the updated model are also compared with those obtained through the original nominal model (which is the one synthesized through nominal parameters of links, like the one in [22]). In (31) and (32), ω i and η i are the ith eigenfrequency and eigenvector estimated through the models (i � 1, .…”

Section: Resultsmentioning

confidence: 99%

“…where η i denotes the transformed experimental eigenvector to be employed in the model updating procedure. e result proposed in (8) is the exact relation that transforms the measured expanded eigenvectors and is an improvement of the approximated one proposed in [22].…”

Section: Mode Shape Transformation From the Physical Referencementioning

confidence: 87%

“…erefore, more reliable solutions can be achieved compared to [22] that effectively handle a larger number of vibrational modes over a larger frequency range.…”

Section: Formulation Of the Inverse Eigenproblemmentioning

confidence: 99%

“…e formulation of an effective approach imposes several steps that are carefully accounted for in this work. Some preliminary results have been proposed by the authors in conference paper [22], which outlines the method idea through a simplified approach. e method is here extended to deal with a larger number of vibrational modes and constraints through an improved formulation which ensures more precise results and accounts for more measurements: not only the proposed approach is capable of exploiting more modal data, but also it takes advantage of information on the static behaviour of the mechanism.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

An Updating Method for Finite Element Models of Flexible‐Link Mechanisms Based on an Equivalent Rigid‐Link System

Belotti

Caracciolo

Palomba

et al. 2018

Shock and Vibration

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This paper proposes a comprehensive methodology to update dynamic models of flexible-link mechanisms (FLMs) modeled through ordinary differential equations. The aim is to correct mass, stiffness, and damping matrices of dynamic models, usually based on nominal and uncertain parameters, to accurately represent the main vibrational modes within the bandwidth of interest. Indeed, the availability of accurate models is a fundamental step for the synthesis of effective controllers, state observers, and optimized motion profiles, as those employed in modern control schemes. The method takes advantage of the system dynamic model formulated through finite elements and through the representation of the total motion as the sum of a large rigid-body motion and the elastic deformation. Model updating is not straightforward since the resulting model is nonlinear and its coordinates cannot be directly measured. Hence, the nonlinear model is linearized about an equilibrium point to compute the eigenstructure and to compare it with the results of experimental modal analysis. Once consistency between the model coordinates and the experimental data is obtained through a suitable transformation, model updating has been performed solving a constrained convex optimization problem. Constraints also include results from static tests. Some tools to improve the problem conditioning are also proposed in the formulation adopted, to handle large dimensional models and achieve reliable results. The method has been experimentally applied to a challenging system: a planar six-bar linkage manipulator. The results prove their capability to improve the model accuracy in terms of eigenfrequencies and mode shapes.

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Section: Resultsmentioning

confidence: 99%

Section: Mode Shape Transformation From the Physical Referencementioning

confidence: 87%

“…erefore, more reliable solutions can be achieved compared to [22] that effectively handle a larger number of vibrational modes over a larger frequency range.…”

Section: Formulation Of the Inverse Eigenproblemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

An Updating Method for Finite Element Models of Flexible‐Link Mechanisms Based on an Equivalent Rigid‐Link System

Belotti

Caracciolo

Palomba

et al. 2018

Shock and Vibration

View full text Add to dashboard Cite

show abstract

“…The modulus plot highlights the presence of the fundamental mode at about 13 Hz, and the phase plot corroborates this fact, showing large phase changes at the same frequency. The tests were carried out with the modal analysis approach [20], which is widely used in the fields of automotive engineering [21,22], aerospace engineering [23], automatic machines [24], and robotics [25]. A grid of measurement points was defined on the robot (see Figure 5); points 10 and 11 were used to monitor base vibrations.…”

Section: Testing Equipment and Methodsmentioning

confidence: 99%

Analysis of the Compliance Properties of an Industrial Robot with the Mozzi Axis Approach

et al. 2019

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In robotic processes, the compliance of the robot arm plays a very important role. In some conditions, for example, in robotic assembly, robot arm compliance can compensate for small position and orientation errors of the end-effector. In other processes, like machining, robot compliance may generate chatter vibrations with an impairment in the quality of the machined surface. In industrial robots, the compliance of the end-effector is chiefly due to joint compliances. In this paper, joint compliances of a serial six-joint industrial robot are identified with a novel modal method making use of specific modes of vibration dominated by the compliance of only one joint. Then, in order to represent the effect of the identified compliances on robot performance in an intuitive and geometric way, a novel kinematic method based on the concept of “Mozzi axis” of the end-effector is presented and discussed.

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