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1
Content available The MEMS-based barometric altimeter inaccuracy and drift phenomenon
Matyja Tomasz, Kubik Andrzej, Stanik Zbigniew
Zeszyty Naukowe. Transport / Politechnika Śląska
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2022
|
z. 116
141--162
EN
MEMS technology has made sensors for measuring barometric pressure and altitude above sea level very cheap and widely used in many consumer electronic devices. This paper presents a theoretical analysis of the sources and types of errors in the barometric altimeter using the standard atmosphere model (ISA). Methods for correcting principal errors caused by non-standard sea level conditions are described and compared. A method of correcting errors in the case of altimeter horizontal movement to the air column and total pressure measurement was proposed. It was compared with another method known from the literature. In the numerical experiment, data recorded by a bicycle computer equipped with a MEMS-based barometric altimeter was analyzed. As the GPS data of the route covered was also known, it was possible to compare the recorded altimeter data with the heights determined from the digital terrain model (DTM), which in this case were considered accurate. The error of the measured altitude calculated in this way was tried to be divided into the principal error, the external error caused by the sensor movement, and the barometer drift. Hence, a numerical experiment was carried out in which, based on the recorded data, an attempt was made to reconstruct non-standard sea level conditions and the impact of speed on the sensor measurements. Furthermore, a method of solving such a reverse problem was proposed. The results of the presented studies can be used in the design of systems correcting the indications of barometric altimeters. The accuracy of the altitude measurement is especially important for small controlled flying objects (UAH) and when recording the route of vehicles moving on the ground.
2
Content available Simulation tests of fleet vehicles periodic inspections timeliness: a case study
Matyja Tomasz, Stanik Zbigniew
Zeszyty Naukowe. Transport / Politechnika Śląska
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2022
|
z. 115
75--91
EN
This study analyzed the case of a medium-sized workshop and the income from servicing individual customers. The management of the company observed some unused potential in the garage and plans to sign contracts with fleet customers for comprehensive maintenance of their vehicles. The key question was how many fleet vehicles could be additionally serviced without losing individual customers? In this work, a simulation model of a workshop was developed, treated as a system for queuing orders and vehicles. The model includes a subsystem of random generation of fleet vehicle mileage during the simulation. The idea of event-driven simulation and the Matlab/Simulink SimEvent environment library was used.
3
Content available Impact of the Static Pressure Measurement Accuracy on Barometric Altimeter Errors
Stanik Zbigniew, Matyja Tomasz, Kubik Andrzej
Safety & Defense
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2022
|
2
62--71
EN
The horizontal movement of the pressure sensor in relation to air masses may cause erroneous indications of the altimeter due to the possible measurement of the total pressure, which is the sum of the static and dynamic pressure. This problem mainly concerns devices of small dimensions equipped with barometric altimeters made in MEMS technology, performing complex movements. Small dimensions make it difficult to arrange the pressure intake slots in a way that ensures the measurement of static pressure. Examples include drones (UAH) or bike computers. The aim of the research was to develop an altitude correction formula depending on the speed of the pressure sensor relative to air, which, contrary to those found in the literature, would take into account changes in air density with altitude. The theoretical analysis of the influence of the speed of movement on the indications of the barometric altimeter was evaluated in this paper based on the standard atmosphere model. Methods of correcting errors caused by the measurement of total pressure were proposed. The effectiveness of the proposed methods was verified with simulations (Matlab). Experimental studies were also carried out, which confirmed the theoretical considerations. The experiments performed showed that the problem of correcting errors caused by incorrect measurement of static pressure is very complex. The inertia of the barometer indications plays an important role. The direction of airflow and pressure distribution on the flowing object are also important. The results presented in this paper can be used in the design of systems that improve the quality of barometric altimeter readings. This is particularly important when designing low-budget drone navigation systems and it will improve flight safety.
4
Content available Methods for assessing the technical condition of bearing hubs in means of transport
Stanik Zbigniew, Kubik Andrzej, Hadryś Damian, Csiszár Csaba
Zeszyty Naukowe. Transport / Politechnika Śląska
|
2021
|
z. 113
191--204
EN
This article presents two methods of testing bearing hubs, which may supplement the existing subjective and unreliable methods of diagnostics of rolling bearings used in wheel bearing hubs of motor vehicles and other means of road transport. One of the most important elements responsible for the safety of a vehicle is the bearing hub. Regular monitoring of the technical condition of bearings should become an obligation at vehicle inspection stations when carrying out a technical inspection of a vehicle, authorising it to travel on public roads. This article presents the results of vehicle tests with signs of damage to rolling bearings, using two test stands: one on which the dynamic balancer acted as a device for accelerating the wheel, and the other, which was designed as a test dedicated to automotive rolling bearings, where a dynamic weighbridge was used as the wheel drive, made it impossible to test the wheel at lower rotational speeds. The newly designed and manufactured bearing testing device eliminates the disadvantages of the previous stand, and additionally, enables the measurement of a fully loaded bearing hub, which enables the simulation of real operating conditions on the bearing hub.
5
Content available Impact of selected operational parameters on measures of technical condition of rolling bearings in means of transport built based on analysis of vibration signals
Kubik Andrzej, Stanik Zbigniew, Hadryś Damian, Csiszár Csaba
Zeszyty Naukowe. Transport / Politechnika Śląska
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2021
|
z. 111
89--98
EN
This article presents an innovative method of diagnostics of rolling bearings used in the bearing nodes of motor vehicles, with the use of a prototype specialist stand. The tests were carried out based on a developed research plan, which included the impact of damage to the bearing and tyre of the vehicle, as well as the vehicle speed. Vibration accelerations were recorded in three measurement axes. Signal spectra were created based on the time courses of the vibration signals and were further analysed. The presented method is aimed at detecting excessive wear of rolling bearings in wheels from its early period.
6
Content available Deceleration and deformation during dynamic loading of model car body parts after post-accident repair
Hadryś Damian, Kubik Andrzej, Stanik Zbigniew
Transport Problems
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2020
|
T. 15, z. 3
5--16
EN
Absorption of impact energy by the passive safety elements of the vehicle body is the basic feature to ensure conditions of safety for the driver and passengers in transport. The parts especially designed for this objective in the self-supporting car body are longitudinals. Their energy-absorbing features are designed in different ways. Evaluation of the degree to which the vehicle (body) ensures safety during a collision is difficult and expensive. Usually, tests under impact conditions are required. The most advanced and costly are the tests carried out on a complete vehicle (whole real object for tests). Whole vehicle testing can be replaced by testing of individual car body elements (for example longitudinal). The main aim of this article is to present and compare the results of dynamic studies on model energy-consuming objects (new model longitudinals and model longitudinals repaired with welding methods). For the purpose of this study, models of vehicle passive safety elements (model longitudinals) were designed. On the basis of the conducted tests, it was found that it is worth considering the replacement of collision tests of the whole vehicle by tests of its individual components. This can be considered a new approach that is not widely used. Currently, most often, crash tests of entire vehicles are conducted (high costs) or computer simulations are performer (often with unsatisfactory accuracy).
7
Content available Welding mobile platforms elements made of AHSS steel in view of new requirements in civil engineering and transport
Węgrzyn Tomasz, Jurek Adam, Wszołek Łukasz, Stanik Zbigniew
Zeszyty Naukowe. Transport / Politechnika Śląska
|
2019
|
z. 103
209--218
EN
The developing automotive industry has prompted an increase in the demand for new welding technologies in civil engineering and transport that reduce the mass of mobile platforms mounted on vehicles and increase their operational range at the same time. The AHSS steels are the materials most commonly adapted for the production of motor vehicles due to their high tensile strength. Nonetheless, the joints created with their use are less strong from the native material. This article examined whether the application of micro-jet cooling would alter the mechanical properties of the welds. Based on the performed tests, joints with better quality that passed positively in the hardness and tensile strength evaluations were obtained. The presented research proves that the use of additional elements in the welding process significantly affects the quality of the obtained welds and brings satisfactory results with a greater repeatability than before.
8
Content available Analysis of tribological wear in block – on ring contact on tribological tester T-05
Kubik Andrzej, Hadryś Damian, Stanik Zbigniew, Jasiok Marek
Zeszyty Naukowe. Transport / Politechnika Śląska
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2019
|
z. 105
113--123
EN
Friction is one of the most common phenomena in this technique. The friction process in the tribography systems causes both energy losses and consumption process losses. The layer of the surface of a solid body differing from the material to the entire volume of the solid is a close participant in the tribological process. The effects of external influences during treatment of the material and in friction processes were established and modified. The well-shaped layer of the surface provided optimum tribological properties during operation. This work provides an analysis of the use of a tribological pair working in a rotational movement, in different operating conditions. The tests carried out showed the impact of the selected exploitation factors, that is, the speed and load, the consumption and the friction coefficient of the saliva and the graphical interpretation of results from the results obtained from experimental and metallographical studies. The tests carried out in the block-on ring position of the T-05 tribology was the nature of preliminary tests. Preliminary tests enabled the effects of designated performance parameters to be determined on selected tribological properties. Low-carbon steel used for heat-chemical treatment and steel with DLC coating was used for the test. Metallographic studies enabled the dominant use mechanism to be determined, depending on external factors. The application of the above-mentioned value for materials currently used in various types of constructions allows for extending the life of a given device without major financial and constructional costs. A wide range of applications can bring many benefits to the current design solutions, in which the efficiency of the entire device can be easily improved.
9
Content available Analysis of shaft wear in turbocharges of automotive vehicles
Hadryś Damian, Bąkowski Henryk, Stanik Zbigniew, Kubik Andrzej
Transport Problems
|
2019
|
T. 14, z. 3
85--95
EN
The article presents the results of the investigations of turbocharger shaft bearing using different kinds of lubrication conditions (dry friction and lubrication with different kind of oils). In particular, the wear of the turbocharger shaft surface was evaluated. One of the most frequent failures is the seizure of the turbocharger shaft in the slide bearing, causing its rotation, which leads to destruction of the assembly and costly repairs. On the basis of the conducted tests, it was found that the average value of representative breaks surface on the turbocharger shaft are reduced using of a less viscous oil. Similar situation was seen using new oil instead overworked oil – it had an influence on the value of diameter of breaks.
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