Mobility and Singularity Analysis of a Class of 2-DOF Rotational Parallel Mechanisms Using a Visual Graphic Approach

Yu, Junsheng; Dong, Xin; Pei, Xitong; Zong, Guanghua; Kong, Xianwen; Qiu, Qunxian

doi:10.1115/detc2011-48274

Cited by 9 publications

(4 citation statements)

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“…8). According to the previous research [34,35], the static equation of the compliant parallel manipulators can be established in the form of the force and moment constraints of the upper platform (i.e., from external and internal loads of the compliant joints) (Fig. 8).…”

Section: A Kinetostatic Modelling Of a Single Compliant Limbmentioning

confidence: 99%

Modeling and Experimental Validation of a Compliant Underactuated Parallel Kinematic Manipulator

Dong

Axinte

2020

IEEE/ASME Trans. Mechatron.

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Parallel kinematic manipulators (PKMs) are increasingly used in a wide range of industrial applications due to the characteristics of high-accuracy and compact structure. However, most of the existing PKMs are structured with heavy actuators and high stiffness. In this respect, this paper proses a simple, yet effective, parallel manipulator that distinguishes itself through: (1) under-actuation: it employs only a single motor and a driving cable to actuate its three legs; (2) novel foot location: it uses a smart shape memory alloy (SMA) clutch-based driving system (SCBDS) which catches/releases the driving cable, thus, making possible the robot under-actuation; (3) adjustable compliance: its double compliant joints on each limb with a stiffness-adjustable section which renders a safe human-robotic interaction. To support and predict the performance of this underactuated compliant manipulator, a novel kinetostatic model was developed by considering the generalized internal loads (i.e. force and moment) in three compliant limbs and the external loads on the upper platform. Finally, based on the physical prototype, a set of experiments were conducted to validate the model proposed in this paper. It was found that the proposed kinetostatic model can be validated with the average deviations of 1.8% in position and 2.8% in orientation respectively. Further, the workspace of the system (e.g. discrete and continuous workspace) was studied when different actuating strategies were employed, thus emphasizing the advantages and the limitations of this novel system.

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Section: A Kinetostatic Modelling Of a Single Compliant Limbmentioning

confidence: 99%

Modeling and Experimental Validation of a Compliant Underactuated Parallel Kinematic Manipulator

Dong

Axinte

2020

IEEE/ASME Trans. Mechatron.

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“…Wu et al [20] introduced the term 'equal spherical pure rotations' (ESPR) to describe this form of rotation. They adopted a graphical approach proposed by Yu et al [21] to deduce the freedom and complementary constraint patterns (FCCPs) inherent in robots with ESPR characteristics. Their classification system identified three distinct types of these mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Kinematic Analysis of a New 3-DOF Parallel Wrist-Gripper Assembly with a Large Singularity-Free Workspace

Ghaedrahmati,

Gosselin

2023

Actuators

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This paper introduces a novel dexterous 3-DOF parallel wrist-gripper assembly with a large singularity-free range of motion. It consists of a zero-torsion 2-DOF parallel wrist and a 1-DOF parallel gripper. The wrist produces a 2-DOF sphere-on-sphere pure rolling motion. This large singularity-free 2-DOF sphere-on-sphere pure rolling motion of the wrist allows for smooth and precise manipulation of objects in various orientations, making it suitable for applications such as assembly, pick-and-place, and inspection tasks. Using a geometrical approach, analytical solutions for the inverse and forward kinematics problems of the wrist and gripper are derived. From the inverse kinematic equations, the Jacobian matrices are derived and it is shown that the whole workspace is free of type I and type II singularities. It is shown that with a proper choice of design variables, a large singularity-free range of motion can be obtained. The absence of singularities in the whole workspace of the wrist-gripper assembly is an important feature that enhances its reliability. Finally, the correctness of the derived equations for the wrist inverse and forward kinematics are verified using MSC Adams. These results confirm the feasibility and effectiveness of the proposed parallel wrist-gripper assembly. Overall, the novel parallel wrist-gripper assembly presented in this paper demonstrates great potential for improving the efficiency and flexibility of robotic manipulators in a variety of industrial and research applications.

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“…Its node coordinates include slope coordinates, the element mass matrix is constant, and the stiffness matrix and nodal coordinates are highly correlated. The theory of the ANCF method does not contain the hypothesis of small turning angle motions [3][4][5][6][7], which is the most significant advantage compared to the classic FEM; hence, it is suitable for calculating large deformation problems such as modern flexible fingers or other flexible continuum robots [8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Mechanical Deformation Analysis of a Flexible Finger in Terms of an Improved ANCF Plate Element

Liu

et al. 2022

Machines

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In recent years, flexible continuum robots have been substantially developed. Absolute nodal coordinates formulation (ANCF) gives a feasible path for simulating the behavior of flexible robots. However, the model of finger-shaped robots is often regarded as a cylinder and characterized by a beam element. Obviously, this is short of characterizing the geometrical feature of fingers in detail, especially under bending conditions. Additionally, for the lower-order plate element, it is hard to characterize the bending behavior of the flexible finger due to fewer nodes; a higher-order plate element often requires an extremely long computing time. In this work, an improved ANCF lower-order plate element is used to increase the accuracy of the Yeoh model and characterize the geometrical structure of silicone rubber fingers, taking into particular consideration the effect of volume locks and multi-body system constraints. Since it is a kind of lower-order plate element, essentially, the computing time is nearly the same as that of conventional lower-order plate elements. The validity of this model was verified by comparing it with the results of the published reference. The flexible finger, manufactured using silicone rubber, is characterized by the novel ANCF lower-order plate element, whereby its mechanical deformation and bending behavior are simulated both efficiently and accurately. Compared to the ANCF beam element, conventional lower-order plate element, and higher-order plate element, the novel plate element in this paper characterizes the external contour of the finger better, reflects bending behavior more realistically, and converges in less computing time.

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Mobility and Singularity Analysis of a Class of 2-DOF Rotational Parallel Mechanisms Using a Visual Graphic Approach

Cited by 9 publications

References 0 publications

Modeling and Experimental Validation of a Compliant Underactuated Parallel Kinematic Manipulator

Modeling and Experimental Validation of a Compliant Underactuated Parallel Kinematic Manipulator

Kinematic Analysis of a New 3-DOF Parallel Wrist-Gripper Assembly with a Large Singularity-Free Workspace

Mechanical Deformation Analysis of a Flexible Finger in Terms of an Improved ANCF Plate Element

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