Modal analysis and dynamic responses of a rotating Cartesian manipulator with generic payload and asymmetric load
02 Jan 2020-Mechanics Based Design of Structures and Machines (Taylor & Francis)-Vol. 48, Iss: 1, pp 48-67
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...
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TL;DR: The outcomes indicate that when there is no offset, the decrease in damping results in chaotic generalized modal coordinates, and as the excitation frequency decreases, a limiting amplitude is created at 0.35 before which the behavior of generalized rigid and modal coordinate is different, while this behavior has more similarity after this point.
Abstract: In this article, the nonlinear dynamic analysis of a flexible-link manipulator is presented. Especially, the possibility of chaos occurrence in the system dynamic model is investigated. Upon the oc...
21 citations
Cites background from "Modal analysis and dynamic response..."
...Regarding flexible manipulators, a few number of researches on the analytical methods for bifurcation and chaos exist (Ding et al. 2016; Kumar and Pratiher 2019a, 2019b; Mao, Ding, and Chen 2017a, 2017b; Pratiher and Dwivedy 2011), while most others focused on numerical results (Farokhi and Ghayesh…...
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TL;DR: In this paper, a large deformation analysis of a flexible manipulator is examined by using the discrete time transfer matrix method, which is very demanding in terms of both computational and physical complexity.
Abstract: In this article, a large deformation analysis of a flexible manipulator is examined by using the discrete time transfer matrix method. Since this robotic analysis is very demanding in terms of both...
6 citations
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
4 citations
Cites background or methods or result from "Modal analysis and dynamic response..."
...The stability of the nontrivial solution can be found by adopting the procedure explained in Kumar and Pratiher (2019) and Kumar and Pratiher (2020)....
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...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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01 Mar 2022
TL;DR: In this article , 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
TL;DR: In this article , a string-stiffened single-link flexible manipulator (SSSLFM) with flexible joint has been presented, where the flexibility of the link was stiffened by using a pair of strings while retaining its advantage of being lightweight.
Abstract: In this paper, an innovative method of controlling the endpoint precision of a single-link flexible manipulator has been presented. The flexibility of the link has been stiffened by using a pair of strings while retaining its advantage of being lightweight. The flexible link is modeled as an Euler-Bernoulli beam. Dynamic analyses of the string-stiffened single-link flexible manipulator (SSSLFM) with flexible joint have been carried out using Euler-Lagrange’s formulation with the assumed mode method. The effects of string-stiffening on tip deflection of the link have been found. Coupling effects of string vibration on tip deflection of the link as well as on the joint of the manipulator have also been investigated. It has been observed that by the stiffening of the flexible link with a pair of strings, tip deflection of the link has been reduced significantly. Residual vibrations have been controlled by applying robust proportional-integral and derivative (PID) control.
3 citations
References
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TL;DR: In this article, the free vibration of an Euler-Bernoulli beam with a rigid tip mass whose center of gravity need not be coincident with its point of attachment to the beam is examined.
61 citations
"Modal analysis and dynamic response..." refers background in this paper
...Oguamanam (2003) examined the free vibration of Euler–Bernoulli beam with an offset tip mass having inertia....
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TL;DR: In this paper, a variational formulation of constrained dynamics of flexible multibody systems, using a vector-variational calculus approach, is presented, and a library of kinematic couplings between flexible and/or rigid bodies is defined and analyzed.
Abstract: This paper presents a variational formulation of constrained dynamics of flexible multibody systems, using a vector-variational calculus approach. Body reference frames are used to define global position and orientation of individual bodies in the system, located and oriented by position of its origin and Euler parameters, respectively. Small strain linear elastic deformation of individual components, relative to their body references frames, is defined by linear combinations of deformation modes that are induced by constraint reaction forces and normal modes of vibration. A library of kinematic couplings between flexible and/or rigid bodies is defined and analyzed. Variational equations of motion for multibody systems are obtained and reduced to mixed differential-algebraic equations of motion. A space structure that must deform during deployment is analyzed, to illustrate use of the methods developed.
56 citations
TL;DR: In this paper, the effects of variable axial force on the large amplitude flexural-extensional free vibration of non-uniform cantilever beams carrying a both transversely and axially eccentric tip mass were investigated.
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TL;DR: A frequency response analysis for a rotating cantilever beam is presented in this paper, where the equations of motion derived from Hamilton's principle are transformed into dimensionless forms in which dimensionless parameters are identified.
Abstract: A frequency response analysis for a rotating cantilever beam is presented in this study. The equations of motion are derived from Hamilton's principle. An assumed mode method is used for analyzing the vibration frequency characteristic. The equations are transformed into dimensionless forms in which dimensionless parameters are identified. The effects of rotating angular speed are investigated through numerical study. With the coupling effect ignored, the analysis results are consistent with the results obtained by the conventional method. As the angular speed increases, the bending natural frequencies increase monotonically and the stretching natural frequencies decrease. With the coupling effect considered, when the angular speed increases up to a certain value, there exists the warping speed that is in relation with the slenderness ratio.
28 citations
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...Cheng, Xu, and Yan (2006) presented a frequency response analysis for a rotating Euler–Bernoulli cantilever beam with no payload and effects of rotating angular speeds have been investigated numerically....
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TL;DR: In this paper, the nonlinear vibration of a cantilever beam with tip mass subjected to periodically varying axial load and magnetic field has been studied and the temporal equation of motion of the system containing linear and nonlinear parametric excitation terms along with nonlinear damping, geometric and inertial types of nonlinear terms has been derived and solved using method of multiple scales.
Abstract: In this paper, nonlinear vibration of a cantilever beam with tip mass subjected to periodically varying axial load and magnetic field has been studied. The temporal equation of motion of the system containing linear and nonlinear parametric excitation terms along with nonlinear damping, geometric and inertial types of nonlinear terms has been derived and solved using method of multiple scales. The stability and bifurcation analysis for three different resonance conditions were investigated. The numerical results demonstrate that while in simple resonance case with increase in magnetic field strength, the system becomes unstable, in principal parametric or simultaneous resonance cases, the vibration can be reduced significantly by increasing the magnetic field strength. The present work will be very useful for feed forward vibration control of magnetoelastic beams which are used nowadays in many industrial applications.
22 citations
"Modal analysis and dynamic response..." refers background in this paper
...The nonlinear responses of a single link manipulator having point payload under harmonically varying magnetic field and axial force have been studied by Pratiher and Dwivedy (2011)....
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