Modal Analysis of a 7 DoF Sweet Pepper Harvesting Robot

Berninger, Tobias F. C.; Fuderer, Sebastian; Rixen, Daniel J.

doi:10.1007/978-3-030-12684-1_16

Cited by 7 publications

(4 citation statements)

References 10 publications

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“…In another study for a biomedical application, Faieghi et al [14] utilized an empirical approach to study tool vibrations in a robot-driven human glenoid reaming procedure. In [15], experimental modal analysis was used to investigate the effects of non-linearities in joints, different operational poses and the dynamic behavior of a 7-DOF harvesting robot manipulator. In [16,17], the authors presented dynamic models of flexible-joint 6-DOF robot manipulators.…”

Section: Introduction 1motivation and Backgroundmentioning

confidence: 99%

Vibration Analysis of a 5-DOF Long-Reach Robotic Arm

et al. 2022

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In this paper, dynamic and vibration characteristics of a newly developed 5-degrees-of-freedom (5-DOF) long-reach robotic arm for farm applications is studied through finite element analysis (FEA), as well as experimentally. The new manipulator is designed to be light and compact enough that it can be mounted on a small vehicle for farm applications. A finite element model of this novel manipulator was established using a commercial FEA software. FEA was carried out for two different configurations of the manipulator (fully-extended and vertical half-extended). The fully-extended configuration provides the longest reach of the arm and is one of the most commonly used poses in farm applications; vibrations of this configuration are highly affected by its base excitation. The FEA results indicated that the first six natural frequencies of the manipulator for the two configurations considered were between 4.4 to 41.6 (Hz). Modal analysis on the fully-extended configuration was completed using experimental modal analysis to verify the finite element results. In the experiments, acceleration data were obtained utilizing sensors, and were post-processed using Fast-Fourier Transforms. The first six natural frequencies and their corresponding mode shapes were obtained using FEA and also experimentally, and the results were compared; the comparison showed good agreement, with less than 10% difference. Our verified FE model provides a reliable basis for future vibration control for the newly developed robotic arm for different applications. A harmonic response simulation was also carried out using an experimentally corrected FE model; this provides a good understanding of the dynamic behavior of the newly developed arm under base excitation. This paper offers an experimentally corrected FEA model for a large manipulator with base excitation for farm applications.

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Section: Introduction 1motivation and Backgroundmentioning

confidence: 99%

Vibration Analysis of a 5-DOF Long-Reach Robotic Arm

et al. 2022

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“…In literature, different strategies based on FEM and experimental procedures to estimate NFs in robots have been presented [ 15 , 16 , 17 , 18 ]. FEM is the most used experimental procedure for vibration measurements integrated with signal processing techniques because it can estimate the real behavior of robots [ 19 , 20 , 21 , 22 , 23 , 24 ].…”

Section: Introductionmentioning

confidence: 99%

Natural Frequencies Identification by FEM Applied to a 2-DOF Planar Robot and Its Validation Using MUSIC Algorithm

Martínez-Cruz

Amezquita-Sanchez

Pérez-Soto

et al. 2021

Sensors

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In this paper, the natural frequencies (NFs) identification by finite element method (FEM) is applied to a two degrees-of-freedom (2-DOF) planar robot, and its validation through a novel experimental methodology, the Multiple Signal Classification (MUSIC) algorithm, is presented. The experimental platforms are two different 2-DOF planar robots with different materials for the links and different types of actuators. The FEM is carried out using ANSYS™ software for the experiments, with vibration signal analysis by MUSIC algorithm. The advantages of the MUSIC algorithm against the commonly used fast Fourier transform (FFT) method are also presented for a synthetic signal contaminated by three different noise levels. The analytical and experimental results show that the proposed methodology identifies the NFs of a high-resolution robot even when they are very closed and when the signal is embedded in high-level noise. Furthermore, the results show that the proposed methodology can obtain a high-frequency resolution with a short sample data set. Identifying the NFs of robots is useful for avoiding such frequencies in the path planning and in the selection of controller gains that establish the bandwidth.

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“…Most proposed control techniques assume either the joint torque or motor position as the control input and rely on the accurate knowledge of the underlying system dynamics [3,4]. Measurements of the pose dependent structural dynamics of a robot manipulator are for example shown in [5]. Measurements of the pose dependent structural dynamics of a robot manipulator are for example shown in [5].…”

Section: Introductionmentioning

confidence: 99%

“…In practice, a full dynamic model of a robot manipulator is difficult to acquire using measurements and even harder to predict with just simulation data. Measurements of the pose dependent structural dynamics of a robot manipulator are for example shown in [5].…”

Section: Introductionmentioning

confidence: 99%

External Vibration Damping of a Robot Manipulator's TCP Using Acceleration Feedback

Berninger¹,

Rixen²

2019

Proc Appl Math and Mech

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There are multiple possible applications, which demand high accuracy from industrial robot arms. The usual approach to improve the path accuracy of these robot manipulators is to make the mechanical design as stiff as possible and to employ high fidelity joint controllers, which compensate path inaccuracies with well-identified models of the manipulator system. These methods are, however, only available to the robot manufactures themselves during their development phase. Companies designing tools for specific high accuracy tasks generally cannot change the design of a given robot manipulator and are bound to its precision. An alternative concept to further increase the path accuracy of a robot manipulator, without making changes to its design itself, might be to employ traditional Active Vibration Damping techniques by adding a supplementary proofmass actuator to the robots tool center point with collocated acceleration sensor feedback. This paper explores the feasibility of this idea within a multi body simulation of a simple robot manipulator, which consist of rigid links, flexible joints and is actuated by cascaded joint controllers. The performance of an acceleration feedback controller employed on the robots TCP is evaluated by a test trajectory.

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Modal Analysis of a 7 DoF Sweet Pepper Harvesting Robot

Cited by 7 publications

References 10 publications

Vibration Analysis of a 5-DOF Long-Reach Robotic Arm

Vibration Analysis of a 5-DOF Long-Reach Robotic Arm

Natural Frequencies Identification by FEM Applied to a 2-DOF Planar Robot and Its Validation Using MUSIC Algorithm

External Vibration Damping of a Robot Manipulator's TCP Using Acceleration Feedback

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