| 1. |
- Christiansson, Anna-Karin, 1947-, et al.
(författare)
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Automation of a robotised metal deposition system using laser melting of wire
- 2008
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Ingår i: 18th International Conference on<em> </em>Flexible Automation and Intelligent Manufacturing (FAIM 2008). - 9789163327575 ; , s. 122-129
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper presents a system for full automation of free-form-fabrication of fully dense metal structures using robotized laser melting of wire. The structure is built of beads of melted wire laid side by side and layer upon layer governed by synchronized robot motion. By full automation is here meant that the process starts with a product specification of a component, and ends in a geometrically validated dense metal component fulfilling industrial material requirements. Due to the complexity of this flexible manufacturing system, a number of different disciplines are involved. This paper discusses mainly the system design, which includes how off-line programming is used for automatic generation of code and how feedback control is used for on-line adjustment of parameters based on desired building properties. To meet industrial needs, the project is carried out in a close cooperation between research and development activities in academy and industry.
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| 3. |
- Heralic, Almir, 1981-, et al.
(författare)
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Automation of Robotized Laser Metal-Wire Deposition
- 2007
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Ingår i: Proceedings of the ninth IASTED International Conference on Control and Applications. - : ACTA Press. - 9780889866652 ; , s. ID 658-075-
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Konferensbidrag (refereegranskat)
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| 4. |
- Heralic, Almir, 1981-, et al.
(författare)
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Control Design for Automation of Robotized Laser Metal-Wire Deposition
- 2008
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Ingår i: Proceedings of the 17th IFAC World Congress. - : International Federation of Automatic Control. ; , s. 14785-14791
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper a novel approach towards automation of robotized laser metal-wire deposition (RLMwD) is described. The RLMwD technique is being developed at University West in cooperation with Swedish industry for solid freeform fabrication of fully dense metal structures. The process utilizes robotized fibre laser welding and metal wire filler material, together with a layered manufacturing method, to create metal structures directly from a CAD drawing. The RLMwD process can also be used for repair or modification of existing components. This paper faces the challenge of designing a control system for maintaining stable process variables, such as a constant layer height and a stable component temperature, during the entire manufacturing process. Several problems are identified and discussed in the paper, e.g. the difficulty of obtaining the bead height in the weld pool environment. The case study is a repair application for stamping tools, where worn out trim edges are to be repaired. Issues regarding the control design, system identification, and the practical implementation of this application are discussed.
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| 7. |
- Ryberg, Anders, 1973-, et al.
(författare)
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A new Camera Model and Algorithms for higher Accuracy and better Convergence in Vision-based Pose Calculations
- 2006
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Ingår i: Mechatronics and Automation, Proceedings of the 2006 IEEE International Conference on. - 1424404657 ; , s. 194-199
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Konferensbidrag (refereegranskat)abstract
- This paper presents novel strategies for better calibration and pose calculations of a system for determining the pose, i.e. position and orientation, of a camera. The system in question has a camera aimed to be placed on the hand of an industrial robot for welding, but is useful for any application with a need for measuring position and/or orientation. To calculate the pose of the camera circular reference points that can be recognized in the images are distributed in the working area. From their 2D image coordinates the 6D pose of the camera can be calculated. First the system is calibrated, i.e. the positions of the reference points and the camera parameters are determined. This is done by first taking images of the reference points from different locations, and then do a "total calibration" procedure to calculate the unknown parameters. For a specific system, called PosEye, it was concluded that the accuracy needs to be improved for welding applications. Also a method for making the calculations converge more easily, was needed. To meet these demands a new camera model is proposed, and three preprocessing calculation steps are presented. The new camera model increases accuracy by considering more distortion effects. The preprocessing steps give better initial values for more robust convergence of the algorithms and increased accuracy
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| 8. |
- Ryberg, Anders, 1973-, et al.
(författare)
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A new Camera Model for Higher Accuracy Pose Calculations
- 2006
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Ingår i: Industrial Electronics, 2006 IEEE International Symposium on Industrial Electronics. - 1424404967 ; , s. 2798-2802
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Konferensbidrag (refereegranskat)abstract
- A position and orientation (pose) measurement system is being developed. The system, called PosEye, is based on a camera and by using the information in the image, the pose of the camera taking the image can be calculated. The system is aimed to be placed on an industrial robot for welding, but it is flexible and can also be used in many other applications. The accuracy has been measured, and it is concluded that the accuracy needs to be improved for welding applications. To make the pose measurement, reference points, that can be recognized in the image, are distributed in the working area. The positions of the reference points and the parameters in a camera model are initially computed automatically from sample images from a number of directions to the reference points. After this calibration, the pose can be calculated at each sample image. For high accuracy there is a need to have a camera model that takes into account a number of distortion effects, which are further developed in this paper. The new model is used to express an optimization cost function that can be used for both the pose calculation, and the extensive calibration, that determines camera parameters in the camera model and the positions of the reference points
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| 9. |
- Ryberg, Anders, 1973-, et al.
(författare)
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Accuracy Investigation of a Vision Based System for Pose Measurements
- 2006
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Ingår i: Control, Automation, Robotics and Vision, 2006. ICARCV '06. 9th International Conference on. - 1424403413 ; , s. 1-6
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The accuracy of a pose measurement system, called PosEye, is investigated. PosEye is a system for real time measurement of the position and orientation, the pose, of a camera (sensor) using the information in its image. This sensor is aimed to be mounted on an industrial robot for welding. The investigation was done by comparing the PosEye system position output to that of a coordinate measuring machine. Sources of errors are identified, and suggestions for improvements are made
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