Improving Robotic Accuracy through Iterative Teaching

Sawyer, Daniela; Tinkler, L.; Roberts, N. C.; Diver, Ryan

doi:10.4271/2020-01-0014

Cited by 5 publications

(2 citation statements)

References 10 publications

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“…In the robotic drilling system, the six degrees of freedom (6-DOF) series industrial robot is the most commonly used type. The standard 6-DOF series industrial robot usually has good repeat positioning accuracy (Sawyer et al , 2020). However, due to manufacturing and assembly errors, as well as the dynamic deformation error, the absolute positioning accuracy of the standard robot may be worse than 1 mm, which cannot meet the hole position accuracy demand for aerospace drilling (Li et al , 2021).…”

Section: Introductionmentioning

confidence: 99%

Calibration for a robotic drilling system with secondary encoders based on a novel enhanced rigid-flexible coupling model

Yun-fei

Zhang

Huang

et al. 2022

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Purpose This paper aims to propose a novel model and calibration method to improve the absolute positioning accuracy of a robotic drilling system with secondary encoders and additional axis. Design/methodology/approach The enhanced rigid-flexible coupling model is developed by considering both kinematic parameters and link flexibility. The kinematic errors of the robot and the additional axis are considered with a model containing 27 parameters. The elastic deformation errors of the robot under self-weight of links and end-effector are estimated with a flexible link model. For calibration, an effective comprehensive calibration method is developed by further considering the coordinate systems parameters of the drilling system and using a two-step process constrained Levenberg–Marquardt identification method. Findings Experiments are performed on the robotic drilling system that contains a KUKA KR500 R2830 industrial robot and an additional lifting axis with a laser tracker. The results show that the maximum error and mean error are reduced to 0.311 and 0.136 mm, respectively, which verify the effectiveness of the model and the calibration method. Originality/value A novel enhanced rigid-flexible coupling model and a practical comprehensive calibration method are proposed and verified. The experiments results indicate that the absolute positioning accuracy of the system in a large workspace is greatly improved, which is conducive to the application of industrial robots in the field of aerospace assembly.

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Section: Introductionmentioning

confidence: 99%

Calibration for a robotic drilling system with secondary encoders based on a novel enhanced rigid-flexible coupling model

Yun-fei

Zhang

Huang

et al. 2022

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show abstract

“…This can make parametric calibration undesirable for industrial automation users. In [14], the authors demonstrate a non-parametric method of robot calibration through iterative teaching of points. A KUKA KR240 R2900 ultra robot was calibrated by measuring the robot TCP positions using a Leica AT960 tracker with a T-Mac 6 Degrees of Freedom (DoF) probe over 30 runs and calculating a mean attained pose.…”

Section: Introductionmentioning

confidence: 99%

Development of a Non-Parametric Robot Calibration Method to Improve Drilling Accuracy

Scraggs¹,

Smith²,

Sawyer³

et al. 2021

SAE Int. J. Adv. & Curr. Prac. in Mobility

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T he drilling of large quantities of repetitive holes during the manufacture of large aerospace components is often considered a key limiting factor with regards to production efficiency. Whilst the desire within aerospace is to use relatively cheap six axis robot arms with drilling end effector units, their poor accuracy remains an obstacle. Robot calibration presents a way of improving robot accuracy such that aerospace drilling tolerances can be met, without permanently committing metrology equipment to an automation cell during production. Extensive research has been conducted into robot calibration by correcting the kinematic model, known as parametric calibration. This method is highly complex, and calibrates the robot across the entire working volume. This is often not required in industrial drilling applications, as drilling routines are often contained within a smaller volume of the robot reach. In this paper, a nonparametric method of robot calibration is proposed. This method involves calibrating within regions of the working volume where the robot pose is similar, and thus the effects of geometric errors in the kinematic model are roughly constant. By establishing the average positional error for each region, the accuracy can be locally improved by compensation through definition of the tool centre point. The proposed method can be completed without the use of kinematic models or complex mathematics, making it more suitable to industrial users. From experimental trials, a significant improvement in the positional accuracy of holes drilled using a standard six axis robot is reported, from 2 mm to 0.1 mm, well within the requirements of the majority of aerospace applications.

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Precision optimized process design for highly repeatable handling with articulated industrial robots

Gümbel,

Dröder

2024

CIRP Annals

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Improving Robotic Accuracy through Iterative Teaching

Abstract: This is a repository copy of Improving robotic accuracy through iterative teaching.

Cited by 5 publications

References 10 publications

Calibration for a robotic drilling system with secondary encoders based on a novel enhanced rigid-flexible coupling model

Calibration for a robotic drilling system with secondary encoders based on a novel enhanced rigid-flexible coupling model

Development of a Non-Parametric Robot Calibration Method to Improve Drilling Accuracy

Precision optimized process design for highly repeatable handling with articulated industrial robots

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