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| 2. |
- 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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| 3. |
- 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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| 4. |
- 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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| 5. |
- Sikström, Fredrik, 1971-, et al.
(författare)
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3D-Scanning for Weld Distortion Measuring
- 2006
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Ingår i: Instrumentation and Measurement Technology Conference, 2006. IMTC 2006. Proceedings of the IEEE. - : IEEE conference proceedings. - 0780393600 - 0780393597 ; , s. 2132-2137
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Konferensbidrag (refereegranskat)abstract
- Optical three dimensional scanning for weld distortion measurements have been performed for validation, inspection, general visualization and documentation of a robotized welding process. The planning, preparing and processing of the weld is done in a simulation-based concept where computer aided robotics software simulations are integrated with finite element analysis simulations with the objective to reduce global geometrical deformation during welding. The off-line programmed robot paths were used as an input for finite element calculations of temperature fields and distortion in the work piece. In order to validate the finite element model 3D-scannings have been performed before and after every single welding sequence. This paper describes a validation experiment with non-contact measurements of weld distortion and discusses limitations in optical 3D-scanning techniques used for this purpose
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| 6. |
- Yücel, Baris, et al.
(författare)
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Automatic Generation of Multivariable Sampled-data Controllers for Jet-engines
- 2006
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Ingår i: Proceedings of Reglermöte 2006.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this contribution, it is shown how multivariable sampled-data controllers can be generated for a set of linearized models. The size of this set makes an automatic generation of controllers more practical and less time consuming. The control strategy is robust loopshaping according to Glover/McFarlane. The generated controllers are to be used for the military turbofan engine F404-RM12 which is currently used in the Swedish air fighter JAS39 Gripen.
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