Error Model and Accuracy Analysis of a Six-DOF Stewart Platform

Wang, Shih Ming; Ehmann, Kornel F.

doi:10.1115/1.1445148

Cited by 80 publications

(36 citation statements)

References 16 publications

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“…The studies by Sandia National Laboratories [3] and the National Institute of Standard and Technology [4] reported that two commercially scaled hexapod prototypes have the horizontal stiffness of 7 ∼ 46 N/µm and 32-71 N/µm varied in the working zone. Another work [5] also stated that a commercially scaled hexapod There is an extensive body of literature [6][7][8][9][10][11][12][13][14][15][16][17][18] devoted to the characterisation, calibration and compensation for the error sources in PKMs, using either external devices for direct calibration or internal sensors for self-calibration. However, implementing these methods in a machine shop environment is a challenging task for machine builders.…”

Section: Introductionmentioning

confidence: 99%

Error analysis and auto-calibration for a Cartesian-guided tripod machine tool

Hsu

Chen

2004

Int J Adv Manuf Technol

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This paper focuses on the error analysis and calibration methodologies for a parallel kinematic machine (PKM) called a Cartesian-guided tripod (CGT). The CGT volumetric error due to the geometric error, kinematic parameter error and nonlinear machine stiffness were studied. It is well known that the PKM nonlinear machine stiffness can produce significant volumetric errors from several tens to several hundreds of micrometres depending on the averaged value and deviation range for the machine stiffness. For most PKMs, joint level sensors are used to estimate the virtual Cartesian movements of the cutting tool. The nonlinear stiffness effect is not detected by this indirect metrology method and must be compensated for by a calibration methodology. A solution for the nonlinear stiffness effect implemented on the CGT involves using a passive Cartesian guiding/metrology leg that is independent of the driving legs to directly measure the Cartesian movement of the motion platform. Because the metrology loop of the Cartesian guiding/metrology leg is separated from the kinematic loops of the driving legs, the volumetric accuracy of the CGT is immunised against thermal errors and load deformations on the drive mechanisms. The passive Cartesian guiding/metrology leg is also used for the auto-calibration of the CGT kinematic parameters. The auto-calibration methodology and simulation results were studied and reported.

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Section: Introductionmentioning

confidence: 99%

Error analysis and auto-calibration for a Cartesian-guided tripod machine tool

Hsu

Chen

2004

Int J Adv Manuf Technol

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“…Because of unpredictable environment some hexapod elements may have values different from nominal. This can be due to the assembly errors, elastic and thermal deformations, actuator errors and others error sources (Wang, 1995). Model that includes all sources of errors is hardly possible to implement because of nonlinear dependent error sources and most of error elements can't even be calculated or measured.…”

Section: Error Analysismentioning

confidence: 99%

Hexapod Structure Evaluation as Web Service

Jelenkovic

Jakobović

Budin

2004

Proceedings of the First International Conference on Informatics in Control, Automation and Robotics

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Abstract:This paper describes several methods for evaluation of kinematic parameters of a Stewart platform. One of those methods is the calculation of workspace area both in numerical and graphical form. The second method allows us to analyze and estimate inherent mechanism errors that occur due to actuator errors, elastic and thermal deformations and other error sources. Furthermore, another procedure is presented which calculates certain kinematic parameters throughout the workspace area of the model and outputs them as numerical and graphical data. Finally, a forward kinematics algorithm designed for use in real-time conditions and its adaptation is presented. The described algorithms are implemented and made available as web services on the project web site (http://hexapod.zemris.fer.hr/).

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“…Considering all error sources such as the bar length errors, the ball joints and Hooke joints installation errors of 3-UPS-PU parallel mechanism, we use differential transformation method to solve position and orientation error of end-effector [7].…”

Section: Error Modeling Of the Parallel Mechanismmentioning

confidence: 99%

Kinematic Reliability Solution of 3-UPS-PU Parallel Mechanism Based on Monte Carlo Simulation

Cui¹,

Sun²,

Liang³

et al. 2015

TOMEJ

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Abstract:In order to research kinematic reliability of 3-UPS-PU parallel mechanism, the structure and kinematics analysis were performed. Inverse kinematics equation can be derived by homogeneous coordinate transformation formula. Position and orientation output error forward kinematics model was obtained by the differential transformation on the basis of inverse kinematic solution of the position. The curves of the position and orientation output errors can be plotted with a large batch production by adopting Monte-Carlo simulation method. Then kinematic reliability of the mechanism can be solved through the probability statistics method and theoretical solution method respectively. Finally, these two methods were compared with each other. The results illustrate that the results of the two methods are basically consistent, and the mechanism can be work reliably and stably under general operations, which provides some valuable references for the related future research.

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Error Model and Accuracy Analysis of a Six-DOF Stewart Platform

Cited by 80 publications

References 16 publications

Error analysis and auto-calibration for a Cartesian-guided tripod machine tool

Error analysis and auto-calibration for a Cartesian-guided tripod machine tool

Hexapod Structure Evaluation as Web Service

Kinematic Reliability Solution of 3-UPS-PU Parallel Mechanism Based on Monte Carlo Simulation

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