Spatial alignment of joining partners without fixtures, based on component-inherent markings

Fleischer, Jürgen; Lanza, Gisela; Otter, Martin; Elser, Jörg

doi:10.1016/j.jmsy.2013.04.004

Cited by 8 publications

(3 citation statements)

References 19 publications

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“…Bone [10] developed the visual guidance working unit for auto parts based on the robotic fixtureless assembly (RFA). Fleischer [11] developed a new approach based on the intrinsic markers of components, which is suitable for the spatial alignment of components. However, this is not an ideal solution for unstructured components.…”

Section: Review Of the Existing Solutionsmentioning

confidence: 99%

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Research on Assembly Method of Threaded Fasteners Based on Visual and Force Information

2023

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Threaded fastening operations are widely used in assembly and are typically time-consuming and costly. In low-volume, high-value manufacturing, fastening operations are carried out manually by skilled workers. The existing approaches are found to be less flexible and robust for performing assembly in a less structured industrial environment. This paper introduces a novel algorithm for detecting the position and orientation of threaded holes and a new method for tightening bolts. First, the elliptic arc fitting method and the three-point method are used to estimate the initial position and orientation of the threaded hole, and the force impact caused by switching from the free space to the constrained space during bolt tightening is solved. Second, by monitoring the deformation of passive compliance, the position information is introduced into the control process to better control the radial force between the bolt and the threaded hole in the tightening process. The constant force controller and orientation compliance controller are designed according to the adaptive control theory. A series of experiments are carried out. The results show that the proposed method can estimate the initial position and orientation of an M24 bolt with an average position error of 0.36 mm, 0.43 mm and 0.46 mm and an orientation error of 0.65°, 0.46° and 0.59°, and it can tighten the bolt with a success rate of 98.5%.

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Section: Review Of the Existing Solutionsmentioning

confidence: 99%

“…(2) The initial position of threaded holes cannot be estimated. In [9,11], the threaded holes and assembled automobile parts are identified and detected, respectively, without modeling and fitting. Therefore, these two methods cannot be used for precision assembly in unknown and complex environments.…”

Section: Review Of the Existing Solutionsmentioning

confidence: 99%

Research on Assembly Method of Threaded Fasteners Based on Visual and Force Information

2023

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“…The use of 3D vision systems to overcome the limitations of 2D systems has also been investigated. The robotic fixtureless assembly (RFA) reported by Bone [18] and the fixtureless assembly method developed by Fleischer [19] describe a vision-guided work cell for assembling automotive components without fixtures. The 3D positions of the components for alignment are identified by tracking the unique markings placed on the components.…”

Section: Review Of the Existing Solutionsmentioning

confidence: 99%

Robotic assembly of threaded fasteners in a non-structured environment

Dharmara

Monfared

Ogun

et al. 2018

Int J Adv Manuf Technol

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Over the past two decades, a major part of the manufacturing and assembly market has been driven by the increasing demand for customised products. This has created the need for smaller batch sizes, shorter production times, lower costs, and the flexibility to produce families of products-or to assemble different parts-with the same sets of equipment. Consequently, manufacturing companies have deployed various automation systems and production strategies to improve their resource efficiency and move towards right-first-time production. Threaded fastening operations are widely used in assembly and are typically time-consuming and costly. In high-volume production, fastening operations are commonly automated using jigs, fixtures, and semi-automated tools. However, in low-volume, high-value manufacturing, fastening operations are carried out manually by skilled workers. The existing approaches are found to be less flexible and robust for performing assembly in a less structured industrial environment. This motivated the development of a flexible solution, which does not require fixtures and is adaptable to variation in part locations and lighting conditions. As a part of this research, a novel 3D threaded hole detection and a fast bolt detection algorithms are proposed and reported in this article, which offer substantial enhancement to the accuracy, repeatability, and the speed of the processes in comparison with the existing methods. Hence, the proposed method is more suitable for industrial applications. The development of an automated bolt fastening demonstrator is also described in this article to test and validate the proposed identification algorithms on complex components located in 3D space.

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