Wyniki wyszukiwania - BazTech

1

Impact of the Static Pressure Measurement Accuracy on Barometric Altimeter Errors

Stanik Zbigniew, Matyja Tomasz, Kubik Andrzej

Safety & Defense

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2022

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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.

2

Fault-tolerant tracking control for a non-linear twin-rotor system under ellipsoidal bounding

Kukurowski Norbert, Mrugalski Marcin, Pazera Marcin, Witczak Marcin

International Journal of Applied Mathematics and Computer Science

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2022

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Vol. 32, no. 2

171--183

EN

A novel fault-tolerant tracking control scheme based on an adaptive robust observer for non-linear systems is proposed. Additionally, it is presumed that the non-linear system may be faulty, i.e., affected by actuator and sensor faults along with the disturbances, simultaneously. Accordingly, the stability of the robust observer as well as the fault-tolerant tracking controller is achieved by using the ℋ∞ approach. Furthermore, unknown actuator and sensor faults and states are bounded by the uncertainty intervals for estimation quality assessment as well as reliable fault diagnosis. This means that narrow intervals accompany better estimation quality. Thus, to cope with the above difficulty, it is assumed that the disturbances are over-bounded by an ellipsoid. Consequently, the performance and correctness of the proposed fault-tolerant tracking control scheme are verified by using a non-linear twin-rotor aerodynamical laboratory system.

3

Condensation of refrigerant R404A under external disturbances

Bohdal T., Łomiak M.

Archives of Thermodynamics

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2009

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Vol. 30, no. 2

37-57

EN

The paper describes results of experimental investigations of condensation of the refrigerant R404A in the flow through a coiled tube under conditions of external disturbances that occur in refrigeration units. The development and decay of condensation is induced by impulse changes of parameters of the two-phase system, such as pressure and mass flux density in the tubular channel. It is confirmed that the two-phase systems exhibit wave properties and that the disturbances propagate with finite velocities. Experiment-based correlations are obtained to describe the propagation of disturbances during development and decay of condensation of the refrigeration medium in the tubular channel.

4

Wpływ zakłóceń zewnętrznych na jakość akustyczną wnętrz sakralnych

Engel Z., Kosała K.

Mechanika / Akademia Górniczo-Hutnicza im. St. Staszica

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2004

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T. 23, z. 2

155-160

EN

The creation of proper acoustic conditions inside sacral buildings depends on a few factors. The essential thing which influences on acoustic quality of such buildings is the sound level of external disturbances. In proper result of sound level of external disturbances measurements were shown. The proposition of single-numbered index method of acoustic assessment sacral's buildings was shown. The one of the partial indices - the external disturbances index was given in the paper. The applying and comparison of acoustic property of a few churches by proposed index were shown.

PL

Kształtowanie warunków akustycznych obiektów sakralnych zależy od wielu czynników. Istotny wpływ na jakość akustyczną tego typu wnętrz ma poziom dźwięku zakłóceń zewnętrznych. W referacie pokazano wyniki badań poziomu dźwięków zakłócających w kilku obiektach sakralnych. Przedstawiono propozycję jednoliczbowej wskaźnikowej metody oceny jakości akustycznej obiektów sakralnych. Omówiono jeden ze wskaźników cząstkowych - wskaźnik zakłóceń zewnętrznych. Pokazano zastosowanie i porównanie właściwości akustycznych kilku wybranych wnętrz kultu religijnego za pomocą proponowanego wskaźnika zakłóceń zewnętrznych.