Visual measurement system for wheel–rail lateral position evaluation

Railway infrastructure must meet safety requirements concerning its construction and operation. Track geometry monitoring is one of the most important activities in maintaining the steady technical conditions of rail infrastructure. Commonly, it is performed using complex measurement equipment installed on track-recording coaches. Existing low-cost inertial sensor-based measurement systems provide reliable measurements of track geometry in vertical directions. However, solutions are needed for track geometry parameter measurement in the lateral direction. In this research, the authors developed a visual measurement system for track gauge evaluation. It involves the detection of measurement points and the visual measurement of the distance between them. The accuracy of the visual measurement system was evaluated in the laboratory and showed promising results. The initial field test was performed in the Vilnius railway station yard, driving at low velocity on the straight track section. The results show that the image point selection method developed for selecting the wheel and rail points to measure distance is stable enough for TG measurement. Recommendations for the further improvement of the developed system are presented

Vehicle gearbox dynamics: centre distance influence on mesh stiffness and spur gear dynamics

Vehicle gearbox dynamics is characterized by time varying mesh stiffness. The paper presents a survey of methods used for determining mesh stiffness and the analysis of the centre distance influence on it. The refined mathematical transmission model presenting the centre distance as a variable is presented. The centre distance error as well as backlash and bearing flexibility is defined and the influence of these factors on mesh stiffness and spur gear dynamics is investigated. The results obtained from this paper may be used in gear-box diagnostics

Ocena stanu przekładni zębatej z wykorzystaniem rozszerzonego zakresu częstotliwości

The paper focuses on working out an algorithm for spur gear condition monitoring, based on the results of numerical simulation. The nonlinear mathematical model has been used for investigation of the dynamic parameters of the cylindrical spur gear with defective teeth. Backlash between gear teeth, backlash in bearings, time-varying mesh stiffness, and variations of the centre distance have been evaluated in the model. Diagnostic parameters suitable for determining the condition of the gears under investigation have been established. Frequency intervals mostly affected by changes in diagnostic parameters under damage have been found. An algorithm for diagnostics based on mathematical modelling, vibro-acoustic, and acoustic emission methods, and wavelet transform has been worked out.Celem artykułu było opracowanie algorytmu monitorowania stanu przekładni zębatej w oparciu o wyniki symulacji numerycznej. Przedstawiono nieliniowy model matematyczny, który wykorzystano do badania parametrów dynamicznych przekładni zębatej walcowej z uszkodzonymi zębami. Za pomocą przedstawionego modelu oceniano luz pomiędzy zębami przekładni, luz w łożyskach, zmienną w czasie sztywność zazębienia oraz zmiany odległości osi. Ustalono parametry diagnostyczne odpowiednie dla określenia stanu technicznego badanych przekładni. Znaleziono przedziały częstotliwości odpowiadające zmianom parametrów diagnostycznych wynikającymi z uszkodzenia. Opracowano algorytm diagnostyczny oparty na modelowaniu matematycznym, metodach emisji wibroakustycznej i emisji akustycznej oraz transformacie falkowej