Anna Timofiejczuk

Application of selected classification schemes for fault diagnosis of actuator systems

The paper presents the application of various classification schemes for actuator fault diagnosis in industrial systems. The main objective of this study is to compare either single or meta-classification strategies that can be successfully used as reasoning means in off-line as well as on-line diagnostic expert systems. The applied research was conducted on the assumption that only classic and well-practised classification methods would be adopted. The comparison study was carried out within the DAMADICS benchmark problem which provides a popular framework for confronting different approaches in the development of fault diagnosis systems.

Methods of image processing in vision system for assessing welded joints quality

The paper deals with methods of image processing applied in a vision system for assessing welded joints quality. The vision system consists of two CCD and one infrared camera. The base of elaborated approaches to joint assesment is a set of images taken in infrared and visible light during welding process. Images taken in visible light are sources of information about outer conditions of the joint, while thermograms let us to obtain information concerning the joint interior. In the paper results of the application of processing of these two types of images are presented.

Mobile robot for inspecting ventilation ducts

The paper deals with a concept and design of a mobile robot capable of inspecting ventilation ducts made of steel sheet. The robot can operate in several modes including: autonomous, manual, and training one. Some subsystems are briefly outlined. Mobility of the robot is achieved by four wheels that include permanent magnets. There are 2 DOFs associated to each wheel. The detection system assesses the internal state of the robot and its subsystems, and perceives the surrounding environment, providing the control system with vital data that allows completing inspection tasks. The robot is also equipped with environment recognition system that collects data whose meaning is twofold. Primarily, it allows assessing actual condition of the ducts being inspected. Further on, the data makes possible creating plans of long-term movements that are required in order to complete the mission. The work of all these systems is coordinated by the control system. It is based on behaviors that are selected or combined by a neural controller. The controller is able to learn better behaviors from examples. These issues are discussed in details in other papers presented at this event.

Environment detection and recognition system of a mobile robot for inspecting ventilation ducts

The system of environment detection and recognition is a part of a mobile robot. The task of the robot is to inspect ventilation ducts. The paper deals with elaborated methods of data and image transmission, image processing, analysis and recognition. While developing the system numerous approaches to different methods of lighting and image recognition were tested. In the paper there are presented results of their applications.

Actuator Fault Diagnosis Using Single and Meta-Classification Strategies

The paper presents the application of various classification schemes for actuator fault diagnosis in industrial systems. The main objective of this study is to compare either single or meta-classification strategies that can be successfully used as reasoning means in the diagnostic expert system that is realized within the frame of the DISESOR project. The applied research was conducted on the assumption that classic as well as soft computing classification methods would be adopted. The comparison study was carried out within the DAMADICS benchmark problem which provides a popular framework for confronting different approaches in the development of fault diagnosis systems.

Welding process evaluation on the basis of video and thermal images

The progress of the welding process has a decisive impact on the quality of weld joints. Obtaining welded joints of high quality, both in terms of their mechanical and aesthetic properties, requires selection of appropriate welding process parameters and, most importantly, maintaining their stability during joint formation. While the choice of welding parameters is not a problem for an experienced welder, ensuring stability of the process is not an easy task. The stability of the welding process is affected by many interfering, often random factors, such as disruption of stability of filler feed, dirt and inaccuracy of edge preparation of the joined materials, deformation of the joined elements due to thermal expansion of the material. These factors cause welding unconformities, such as excessive melting, lack of penetration, cracks, burns, too large risers or depressions in the face of the weld, presence of bubbles, and other factors. Ensuring that high quality of welded joints is possible by controlling the welding parameters. The method of controlling welding parameters can be based on the measurement of welding parameters (e.g. current, arc voltage, and shielding gas flow). Another way to control the welding process and the welded joints is the use of visual inspection of the welding process, based on recording images of the formed welds in the visible spectrum, as well as in the nearand far-infrared spectrum, and their subsequent analysis and diagnosis. This approach is mentioned in the literature as one of the most promising ways of assessing the welding process and the welded joints. The most important aspect of using visual methods is that their use in volume production enables rapid identification of disturbances in the welding process parameters, errors in positioning of the joined elements and limiting the number of unconformities that appear throughout the series of manufactured components. Visual welding process control clearly provides increased joint quality and reduced production losses.

Development of Expert System Shell with Context-Based Reasoning

The paper focuses on the expert system shell which is proposed as a tool that can be used for a wide spectrum of industrial applications. A new architecture of the system enables reasoning by means of multi-domain knowledge representations and multi-inference engines. Moreover, the extended functionality of the system is developed using a context based approach. The system is implemented applying a data mining software which makes possible to acquire domain-specific knowledge and its direct application in the expert system shell. In this study, the preliminary verification is presented using the data registered by the SCADA system of the water supply network. The case study results are useful to illustrate the merits and limitations of the proposed approach.

Development of Expert System Shell for Coal Mining Industry

The paper deals with the design of an expert system shell for the decision support system that is developed to be used in coal mining industry. A proposed architecture of the system allows reasoning by means of multi-domain knowledge representations and multi-inference engines. The implementation of the system is based on data mining software (RapidMiner) which makes possible to acquire domain-specific knowledge and its application in the expert system shell. In this study, the preliminary verification is presented using DAMADICS simulator that was proposed to compare different fault diagnosis methods. The obtained results show the merits and limitations of the proposed approach.

Application of fused visual and thermal images in monitoring and evaluation of welding processes

This article presents the application results of different methods of merging images recorded using vision cameras and thermal imaging cameras. The images were recorded during the evaluation of a welding process. The object of observation was the welding arc and the welded joint during its cooling phase. Images recorded during GMA welding on two different welding stations have been taken into account. The observations have been conducted using cameras equipped with different optics systems. This article presents an analysis of the influence of different parameters of the optics systems on the resulting fused images. The analysis also considers the pre-processing method to ensure correct matching of images. The study shows that the fused image contains aggregated information useful in online monitoring and quality evaluation of the welding process.

Way of investigatng rotating machinery with the use of the WT

The aim of the paper is to present an application of the WT analysis of vibration signals recorded during the run-up or run-down of rotating machinery. Because of complex research work and complicated signals structure the described experiments need an application of special methods. The very good results have been achieved with the use of the WT analysis. However, it demanded special way of synchronization of analysis parameters as well as choice of basis functions. The results of the WT analysis are very interesting, but at the same time their interpretation is very difficult. There is shown an application of the RSL method in the paper. Its application leads up to partitioning of some signal components. This method can be applied to results of the WT analysis, which facilitates the interpretation of scalograms. Identification of these components with diagnostic knowledge is the base of estimation of phenomena occurred during machinery operation thereby technical state of machinery.