Design of a 4-DOF hybrid PKM module for large structural component assembly

Huang, Tian; Wang, P. F.; Zhao, Xiaolu; Chetwynd, D. G.

doi:10.1016/j.cirp.2010.03.098

Cited by 24 publications

(8 citation statements)

References 7 publications

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“…4 Other propositions of using PKMs for HSM can also be traced in recent publications. [5][6][7][8] As a multiple-axis spindle head with 1T2R capacity, Sprint Z3 head has aroused great interests from industrial and academic fields since its invention. Numerous studies have been conducted on this PKM, ranging from kinematic formulation, 9 workspace prediction, 10 stiffness evaluation 11,12 to parasitic motion 13 and dynamics.…”

Section: Introductionmentioning

confidence: 99%

A modified elasto-dynamic model based static stiffness evaluation for a 3-PRS PKM

Zhao

Zhang

Ruan

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part C:

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This paper proposes a modified elasto-dynamic model for a three-prismatic revolute spherical parallel kinematic machine, in which the flexibility of the prismatic revolute spherical limb structures are accounted in and modeled as a hollowed spatial beam with nonuniform cross section. The governing equations are derived through substructure synthesis and finite element formulation. The stiffness matrix of the platform is then extracted from global stiffness matrix and its characteristics at typical configurations are calculated to reveal complicated coupling effects of diagonal and nondiagonal elements of the stiffness matrix. The concept of principle stiffness and coupled stiffness are proposed and their distributions over the workspace are predicted with numerical simulations in a quick manner. Then the stiffness of the platform is physically interpreted as a kinematically unconstrained rigid body suspended by six screw springs with equivalent spring constants and pitches through eigenscrew decomposition. The distributions of screw spring constants over the workspace are then plotted to demonstrate a duality property. At last, the effects of some design variables such as structural and dimensional parameters on system rigidity performance are investigated with the purpose of providing useful information for the structural design and performance enhancement of the parallel kinematic machine.

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Section: Introductionmentioning

confidence: 99%

A modified elasto-dynamic model based static stiffness evaluation for a 3-PRS PKM

Zhao

Zhang

Ruan

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…As a newly invented 5-DOF PKM, the Exechon machine has been experimentally proven to be competitive in terms of accuracy, reliability, and operation speed [8][9][10][11][12]. Although extensive research and application activities have been carried out on the Exechon [13][14][15], little attention has been paid to its reconfigurable version.…”

Section: Introductionmentioning

confidence: 99%

Conceptual Design and Workspace Analysis of an Exechon-Inspired Parallel Kinematic Machine

Tang

Zhao

Zhang

et al. 2015

Advances in Reconfigurable Mechanisms and Robots II

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Inspired by the commercial application of the Exechon machine, this paper proposed a novel parallel kinematic machine (PKM) named Exe-Variant. By exchanging the sequence of kinematic pairs in each limb of the Exechon machine, the Exe-Variant PKM claims an arrangement of 2UPR/1SPR topology and consists of two identical UPR limbs and one SPR limb. The inverse kinematics of the 2UPR/1SPR parallel mechanism was firstly analyzed based on which a conceptual design of the Exe-Variant was carried out. Then an algorithm of reachable workspace searching for the Exe-Variant and the Exchon was proposed. Finally, the workspaces of two example systems of the Exechon and the Exe-Variant with approximate dimensions were numerically simulated and compared. The comparison shows that the Exe-Variant possesses a competitive workspace with the Exechon machine, indicating it can be used as a promising reconfigurable module in a hybrid 5-DOF machine tool system.

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“…Therefore, the sum of the work, which is generated by the external forces and the works generated by the internal forces along the deformation, must be zero. In the following equations, dx, dy and dz are three translation dimensions due to elastic deformation on the centre point of platform E, while du, df and dc are three rotational components due to elastic deformation on platform E. The stiffness matrix of the based platform has been calculated using equation (13). 20 The virtual work of the hexapods actuator plus that of the tripod would be equal to the virtual work on the end-effector as formulated in equation (18) …”

Section: Stiffness Analysismentioning

confidence: 99%

“…12 The hybrid or planner 3-degree-of freedom (DoF) parallel manipulator is a relatively new configuration of parallel robot which is developed to improve the limited workspace of a 6DoF parallel configuration. 13,14 This made the hybrid parallel robot more efficient to use for ankle rehabilitation.…”

Section: Introductionmentioning

confidence: 99%

Path-planning of a hybrid parallel robot using stiffness and workspace for foot rehabilitation

Rastegarpanah

Rakhodaei

Saadat

et al. 2018

Advances in Mechanical Engineering

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Stiffness is one of the important parameters for estimating the performance of hybrid parallel robots as it is not constant throughout its workspace. The aim of this study is to provide an optimum path based on maximum stiffness within the workspace of a 9-degree-of-freedom hybrid parallel mechanism configuration, which includes nine linear actuators connecting one stationary and two moving platforms in series. The proposed robot is designed for ankle rehabilitation, where accurate and precise movement of lower extremities is required. The design takes advantage of two important characteristics of parallel robots: stiffness and workspace. The proposed methodology to determine the stiffness of hybrid robot in three single axes is based on calculation of position vector of each actuator in any particular pose, by considering the inverse kinematics of the system, in order to obtain the magnitude and direction of the applied forces. The results obtained from the workspace calculations have been compared with those of two standard parallel mechanisms including a 6-degree-of-freedom hexapod and a tripod with 3 degrees of freedom. The stiffness of the robot has been calculated in simulation and then compared with those of a developed prototype hybrid model in two different case studies.

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Design of a 4-DOF hybrid PKM module for large structural component assembly

Cited by 24 publications

References 7 publications

A modified elasto-dynamic model based static stiffness evaluation for a 3-PRS PKM

A modified elasto-dynamic model based static stiffness evaluation for a 3-PRS PKM

Conceptual Design and Workspace Analysis of an Exechon-Inspired Parallel Kinematic Machine

Path-planning of a hybrid parallel robot using stiffness and workspace for foot rehabilitation

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