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Journal ArticleDOI

Influences of generic payload and constraint force on modal analysis and dynamic responses of flexible manipulator

TL;DR: This article presents the dynamic modeling and nonlinear analysis of two-link flexible manipulator with generic payload whose center of gravity is different than the point of attachment with the generic payload.
Abstract: This article presents the dynamic modeling and nonlinear analysis of two-link flexible manipulator with generic payload whose center of gravity is different than the point of attachment with the li
Citations
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Journal ArticleDOI
TL;DR: In this article , the effect of flexibility on the dynamics of a two-link planar manipulator having two revolute joints is investigated and a mathematical model validated through experiments is obtained.
Abstract: In this paper, the effect of flexibility on the dynamics of a two-link planar manipulator having two revolute joints is investigated. For this purpose, a mathematical model validated through experiments is obtained for a Two-link planar manipulator having two revolute joints . The mathematical model takes into account the continuous change of Eigen value due to change of configuration of the manipulator. A general expression for the frequency equation for the vibrating links has been obtained which is found to be time-dependent. The effect of this time-dependency of Eigen values of links on Joint and Tip responses is included in the assumed modes method. In this paper, the types of boundary conditions to be used for the flexible links are also researched upon and it is proposed that first four modes of vibration should be used for exactly modelling the flexible links .

5 citations

Journal ArticleDOI
Li Shuwei1, Shutian Fan1, Gu Jinan1, Xingjia Li1, Huang Zedong1 
TL;DR: In this paper, a blind-Kriging-based natural frequency prediction of the industrial robot is proposed, utilizing the Latin Hypercube Sampling (LHS) technique, and a reliable dataset with 120 samples is generated for surrogate models based on the FEM.
Abstract: High-precision assembly conditions tend to necessitate consideration of the vibration modes of industrial robots. The modal characteristics of complex systems such as industrial robots are highly nonlinear. It means that mechanics experiments and finite element methods (FEM) to evaluate such features are usually expensive. Surrogate models combined with simulation-based design are widely used in engineering issues. However, few investigations apply surrogate models to industrial robots' modal analysis. We propose a practical scheme, i.e., the Blind-Kriging (KRG-B) based natural frequency prediction of the industrial robot, utilizing the Latin Hypercube Sampling (LHS) technique. A reliable dataset with 120 samples is generated for surrogate models based on the FEM. Then, the fourteen surrogate models with different optimization algorithms are evaluated to identify the optimal model for the natural frequency. In addition, the accuracy and robustness of the optimal surrogate model are investigated under different training samples. KRG-B model has better robustness (good fitting accuracy for both higher and lower order modes) and higher computational efficiency (1.133 s, the shortest time among all models). The proposed scheme mapping robot's joint angle and the natural frequency offers a valuable basis for further studying dynamic characteristics in industrial robotics.

3 citations

Journal ArticleDOI
TL;DR: One important aspect of the dynamic performance evaluation of a parallel manipulator is the elastodynamic analysis which calls for the calculation of the stiffness and mass matrices.
Abstract: One important aspect of the dynamic performance evaluation of a parallel manipulator is the elastodynamic analysis which calls for the calculation of the stiffness and mass matrices. In the elastod...

1 citations

Journal ArticleDOI
Yushu Bian1
18 Apr 2022-Machines
TL;DR: In this paper , a nonlinear saturation-based control method was proposed to suppress the primary resonance of a flexible manipulator considering complicated rigid-flexible coupling and modal coupling.
Abstract: When primary resonance occurs, even a small external disturbance can abruptly excite large amplitude vibration and deteriorate the working performance of a flexible manipulator. Most active control methods are effective for non-resonant vibration but not for primary resonance. In view of this, this paper puts forward a new nonlinear saturation-based control method to suppress the primary resonance of a flexible manipulator considering complicated rigid-flexible coupling and modal coupling. A vibration absorber with variable stiffness/damping is designed to establish an energy exchange channel for saturation. A novel idea of modal coupling enhancement is suggested to improve saturation performance by strengthening the coupling relationship between the mode of the vibration absorber and the controlled mode of the flexible manipulator. Through stability analysis on the primary resonance response of the flexible manipulator with the vibration absorber, the saturation mechanism is successfully established and the effectiveness of the saturation control algorithm is validated. On this basis, several important indexes are extracted and employed to optimize saturation control. Finally, a series of virtual prototyping simulations and experiments are conducted to verify the feasibility of the suggested saturation-based control method. This research will contribute to the primary resonance suppression of a flexible manipulator under a complex external excitation environment.

1 citations

References
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Journal ArticleDOI
TL;DR: In this paper, the dynamic instability of rectangular viscoelastic plates subjected to periodic in-plane loads P s + P d cos θt is investigated and the material behavior is given in terms of the Boltzmann superposition principle.
Abstract: The dynamic instability of rectangular viscoelastic plates subjected to periodic in-plane loads P s + P d cos θt is investigated. The material behavior is given in terms of the Boltzmann superposition principle, which allows any linear viscoelastic character. This representation yields an integro-differential equation of motion, for which time-dependent instability regions are determined analytically using the multiple-scales method. It is shown that, due to viscoelasticity, the stability regions are expanded relative to the elastic ones and that a plate which may be initially stable can become unstable after a finite time, unlike in the elastic case. The influence of the static and the dynamic parts of the loads on this region is also investigated.

12 citations


"Influences of generic payload and c..." refers methods in this paper

  • ...(13) and (14), method of multiple scales (Cederbaum 1992; Ghayesh 2010; Ghayesh and Balar 2008; Ghayesh and Moradian 2011; Ghayesh, Kazemirad, and Reid 2012; Xu and Yang 2015) is used....

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Journal ArticleDOI
TL;DR: An appropriate and realistic dynamic modeling of the two-link manipulator taking into account of inertia coupling and geometry compatibility between equations of motion and boundary conditions has been derived using the extended Hamilton’s principle.
Abstract: This present work has made a noteworthy attempt to demonstrate brief modeling of N-link manipulator and subsequent modal characterization along with the determination of static deflection of a two-link flexible manipulator with a payload. In addition, investigation of nonlinear phenomena of dynamic responses under 3:1 internal resonance has also been accomplished considering geometric nonlinearities. An appropriate and realistic dynamic modeling of the two-link manipulator taking into account of inertia coupling and geometry compatibility between equations of motion and boundary conditions has been derived using the extended Hamilton’s principle. The effect of parametric variation on system eigenfrequencies is well tabulated, and the corresponding eigenspectrums are illustrated graphically. Further, the nonlinear phenomena of dynamic solutions have been demonstrated by using MMS of second order for its statutory effect onto the system instability for the existence of S-N bifurcations. The effect of nonlinearities and various design parameters on the dynamic responses and subsequent bifurcations for 3:1 internal resonance has also been demonstrated. The outcome of the present work enables new understanding into the design criterion and performance limitation of multi-link flexible robots.

12 citations


"Influences of generic payload and c..." refers background or methods or result in this paper

  • ...It may be noted that, if we consider a point payload and neglect the harmonic motion of joints along with axially fluctuating load, the present system is identical to Kumar and Pratiher (2019)....

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  • ...The major differences between present work and work presented in Kumar and Pratiher (2019) are consideration of a sizeable payload along with axial constraint force and revolute motion of the joints....

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  • ...Following a similar procedure explained in Kumar and Pratiher (2019), the equations for first link are obtained: O e1ð Þ :H1 p10ð Þ¼0: (17) O e2ð Þ :H1 p11ð Þ¼ 2l1D0p10 2D0D1p10þg1 cos X2T0 g2p10 cos X1T0 : (18) O e3ð Þ :H1 p12ð Þ¼ 2l1 D0p11þD1p10ð Þ 2D0D2p10 2D0D1p11 D21p10 g2p11 cos X1T0 þ g3p10…...

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  • ...…001 þ F0 þ F1 cos X1tð Þð Þw 001 þ c1w1t ¼ 0: (11) q2A2ðw2tt þ xw01Ltt þ xh1tt þ xh2tt w2h1t2 w2w01Lt2 2h1th2tw2 2h2tw2w01Lt 2h1tw2w01Lt w2h2t2Þþ E2I2w 00 2 ð3=2ÞE2A2w022w002 þ ðF0 þ F1 cos ðX1tÞÞw002þ c2w2t ¼ 0: (12) Following a similar procedure explained in Kumar and Pratiher (2019, 2020), Eqs....

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  • ...The governing equations of motion of two-link manipulator derived in Kumar and Pratiher (2019) can be obtained from Eqs....

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Journal ArticleDOI
TL;DR: This paper investigates the vibration control of a two-link flexible manipulator carried by a translational stage using a noncollocated controller based on feedback from the deflection of the virtual spring, which can be measured by a shaft encoder.
Abstract: This paper investigates the vibration control of a two-link flexible manipulator carried by a translational stage. The first and the second links are each driven by a stage motor and a joint motor....

11 citations


"Influences of generic payload and c..." refers background in this paper

  • ...The vibration control of a two-link flexible manipulator with no payload carried by a translational stage has been investigated by Wu, Tang, and Huang (2018)....

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Journal ArticleDOI
TL;DR: A dynamic model of a rotating Cartesian manipulator with a payload whose center of gravity doesn’t coincide with the point of attachment is developed to determine the modal parameters i.e., natural frequency and corresponding mode-shape of the manipulator.
Abstract: Here, investigation to explore the effect of generic payload and externally applied asymmetric load on the calculation of modal parameters and dynamic performance of a rotating flexible man...

8 citations


"Influences of generic payload and c..." refers background or methods or result in this paper

  • ...The stability of the nontrivial solution can be found by adopting the procedure explained in Kumar and Pratiher (2019) and Kumar and Pratiher (2020)....

    [...]

  • ...It may be noted that, if we consider a point payload and neglect the harmonic motion of joints along with axially fluctuating load, the present system is identical to Kumar and Pratiher (2019)....

    [...]

  • ...The major differences between present work and work presented in Kumar and Pratiher (2019) are consideration of a sizeable payload along with axial constraint force and revolute motion of the joints....

    [...]

  • ...Following a similar procedure explained in Kumar and Pratiher (2019), the equations for first link are obtained: O e1ð Þ :H1 p10ð Þ¼0: (17) O e2ð Þ :H1 p11ð Þ¼ 2l1D0p10 2D0D1p10þg1 cos X2T0 g2p10 cos X1T0 : (18) O e3ð Þ :H1 p12ð Þ¼ 2l1 D0p11þD1p10ð Þ 2D0D2p10 2D0D1p11 D21p10 g2p11 cos X1T0 þ g3p10…...

    [...]

  • ...…001 þ F0 þ F1 cos X1tð Þð Þw 001 þ c1w1t ¼ 0: (11) q2A2ðw2tt þ xw01Ltt þ xh1tt þ xh2tt w2h1t2 w2w01Lt2 2h1th2tw2 2h2tw2w01Lt 2h1tw2w01Lt w2h2t2Þþ E2I2w 00 2 ð3=2ÞE2A2w022w002 þ ðF0 þ F1 cos ðX1tÞÞw002þ c2w2t ¼ 0: (12) Following a similar procedure explained in Kumar and Pratiher (2019, 2020), Eqs....

    [...]

Trending Questions (1)
Can the hypothetical modal method be used to model flexible manipulators with complex geometries?

The paper does not mention the use of a hypothetical modal method for modeling flexible manipulators with complex geometries.