Papers by Author: Tomasz Giesko

Abstract: The authors present examples of the developed unique optomechatronic systems for the monitoring of fatigue of materials. The systems employ different solutions from the area of optomechatronic technologies like machine vision methods with single-camera and dual-camera vision systems. Additionally, the article discusses the most important functional features and application possibilities of the developed apparatus.

Abstract: When designing unique optomechatronic systems with the application of innovative solutions, decision making with respect to a number of technical and economic criteria seems to be an essential problem. The multi-criteria decision theory is a process of selecting the best solution to the set of alternatives. The paper presents the application of the TOPSIS method for working towards a solution to decision making in the process of designing a unique measurement vision system. The set of alternatives for the vision system has been considered with regard to benefit and cost criteria. As a result, the best alternative has been identified, which represents the highest similarity to the ideal solution expressed by the value of the relative closeness index.

Abstract: In this paper, the possibilities of detection and measurement of fatigue crack length in welded joints made of steel of duplex type, have been presented. In the investigations there has been used an original research system FatigueVIEW employing advanced optoelectronic techniques and numerical methods of image analysis. The proposed approach enables analysis of the fatigue crack growth during fatigue tests and after their finishing in off-line mode.

Abstract: The paper presents the possibilities of a hybrid vision method based on simultaneous analysis of infrared and vision images for surface inspection of hot aluminium in a manufacturing process. The system consists of a NIR/SWIR camera and a high resolution visual camera, and a computer based image analysis system. The simultaneous analysis of infrared and vision images will enable surface inspection for detecting defects in temperature range from 200°C to 600°C. Thermal images present temperature distribution on the surface, and contain information about the manufacturing process. The analysis of thermograms enables to find areas of temperature irregularity caused by increased friction loads, as well as areas of inhomogeneous emissivity caused by surface defects. Furthermore, information captured by the vision camera is used to detect surface defects. The software developed enables the overlaying of images. The proposed simultaneous thermovision and vision imaging can be applied in industry for in-line monitoring of aluminium extrusion processes.

Abstract: In the paper method of displacement analysis in the cracking zone based on digital image correlation and advanced multi-processor graphic cards procedures was presented. The basic assumption for the discussed displacement and strain measurement method under time variable loads was obtaining high measurement sensitivity by simultaneously minimizing the measurement time consumption. The developed digital procedures for correlation of images has been used for an example of displacement analysis in the crack propagation testing in airplane riveted joints.

Abstract: The article presents a dual-camera vision system for fatigue monitoring composed of a vision unit, a camera positioning set and a computer unit. Vision modules are mounted onto the 4DOF positioning sets, which allows for an easy determination of the position of the camera in relation to the sample. The application of motorized measurement lenses with changeable configuration, thanks to the alteration of the distance of observation and the vision angle, enables the adaptation of the system to different scales of observation of the fatigue processes in the specimen surface. Automatic focus setting is realised with the use of the implemented algorithm. The software developed allows for the analysis of fatigue fracture for two 2D images or the 3D stereovision image.

Abstract: The article presents the structural and geometric synthesis and mechanical parameter choice for a manipulation mechanism for measurement microphone positioning during acoustical tests in anechoic chamber. Usually the aims of acoustical measurements in anechoic chamber are: noise source Sound Power Level estimation, electroacoustical transducer directional characteristics measurement, sound diffusing characteristic of a structure measurement, measurement of Sound Pressure Level on a given measurement grid The specific of that kind of measurements brings up the need of measurement microphone positioning in many points of the measurement space accordingly to relevant standards. In most cases during the tests it is necessary to position the microphone in certain points on the hemisphere. In such cases utilizing of typical microphone stands impedes the measurement and extends the time needed for the tests. Those circumstances led to idea of measurement manipulator construction that would allow changing the microphone position during the measurement accordingly to a specified algorithm. The following assumptions for construction were taken: measurement microphone moves on the hemisphere with a maximal radius of 2 m, the weight of transported object (microphone or other) does not exceed 1 kg, positioning accuracy is 1 mm. Structural and geometric synthesis was made taking into account mounting conditions in anechoic chamber in Department of Mechanics and Vibroacoustics AGH-UST. There were several variants labored that fulfilled the assumptions. The choice of particular solution was made based on: • manipulator drives possible installation analysis with regard to their acoustical noise emission • structure stiffness analysis with regard to assumed positioning accuracy of the microphone Finally a modular construction of manipulator was chosen, which is composed of industrial turntable (built in the level of the wire netting) and two linear motion modules (long axis, short axis). That solution means that the device under test fixed on the turntable rotates in the range of 2π, and the measurement microphone moves on the track of one quarter of a circle. Specific angular position of the linear modules was chosen which allows minimal dimensions of linear modules. Simultaneously the control structure and the software part are developed. The usefulness of the manipulator will be definitely confirmed by a research that should evaluate the influence of the construction elements on the acoustical free field in an anechoic chamber.