Automatic Control of Aircraft Engine in Conditions of Stand Test

2020 ◽  
Vol 21 (2) ◽  
pp. 86-92
Author(s):  
G. P. Shibanov

The general principles of automatic control of aircraft engines and functionally related systems in the conditions of their stand tests are suggested. These principles are prospectively reduced to six sequentially implemented procedures or steps. In accordance with these principles, the control of aircraft engine parameters is carried out by a computer-aided test equipment (CTE) based on a computer complex that implements algorithms based on Boolean algebra and the algebra of events and states. These algorithms allow control procedures to be carried out in dynamic mode in accordance with the schedule of testing an aircraft engine. With this control, the specified sequence of operating modes of the aircraft engine undergoing testing is observed without fixing them in time and with the possibility of skipping or repeating individual modes. Parameters are monitored at each of the next aircraft engine operating modes only after all parameters are checked in the previous mode and the value of the main determining parameter reaches the value determined for this mode. During the period of transient processes, parameters are controlled only at the points of extremum of the values of the main determining parameter with fixing the time of transient processes and determining that. "In the tolerance" or "not in the tolerance" is the checked parameter and the fixed time interval. Upon arrival of the signals from the monitoring object, the time of occurrence of which is unknown, and only the time interval during which they can appear is known, any of the CTE operation modes are terminated, tolerance control of the parameters provided by the program is performed, and the previously interrupted mode is restored. Simultaneously with the tolerance control of the parameters, the time of arrival of the above signals is recorded. The group of emergency parameters is monitored continuously throughout the entire period of stand test.

2017 ◽  
Vol 920 (2) ◽  
pp. 57-60
Author(s):  
F.E. Guliyeva

The study of results of relevant works on remote sensing of forests has shown that the known methods of remote estimation of forest cuts and growth don’t allow to calculate the objective average value of forests cut volume during the fixed time period. The existing mathematical estimates are not monotonous and make it possible to estimate primitively the scale of cutting by computing the ratio of data in two fixed time points. In the article the extreme properties of the considered estimates for deforestation and reforestation models are researched. The extreme features of integrated averaged values of given estimates upon limitations applied on variables, characterizing the deforestation and reforestation processes are studied. The integrated parameter, making it possible to calculate the averaged value of estimates of forest cutting, computed for all fixed time period with a fixed step is suggested. It is shown mathematically that the given estimate has a monotonous feature in regard of value of given time interval and make it possible to evaluate objectively the scales of forest cutting.


1983 ◽  
Vol 32 (1-2) ◽  
pp. 79-90 ◽  
Author(s):  
J. S. Rao ◽  
R. C. Tiwari

The failure time distribution is estimated in the nonparametric context when some of tbe observations arc censored. The time interval is partitioned into fixed class intervals, and number of failures and number censored in each of these intervals are observed. Using a Dirichlet distribution as the prior, the resulting estimates of the survival function and the failure rate have a nice and simple form. If instead of the fixed time intervals, one uses the “natural” intervals formed by the observed failure times, this gives essentially the same results as in Ferauson IUld Phadia (1977), Susarla and Van Ryzin (1976), but in a much simpler way. Bayes estimation under the increasins and decreasing failure rates is also considered, and applications to accelerated life testing are discussed.


1980 ◽  
Vol 12 (01) ◽  
pp. 200-221 ◽  
Author(s):  
B. Natvig

In this paper we arrive at a series of bounds for the availability and unavailability in the time interval I = [t A , t B ] ⊂ [0, ∞), for a coherent system of maintained, interdependent components. These generalize the minimal cut lower bound for the availability in [0, t] given in Esary and Proschan (1970) and also most bounds for the reliability at time t given in Bodin (1970) and Barlow and Proschan (1975). In the latter special case also some new improved bounds are given. The bounds arrived at are of great interest when trying to predict the performance process of the system. In particular, Lewis et al. (1978) have revealed the great need for adequate tools to treat the dependence between the random variables of interest when considering the safety of nuclear reactors. Satyanarayana and Prabhakar (1978) give a rapid algorithm for computing exact system reliability at time t. This can also be used in cases where some simpler assumptions on the dependence between the components are made. It seems, however, impossible to extend their approach to obtain exact results for the cases treated in the present paper.


2012 ◽  
Vol 29 (06) ◽  
pp. 1250033
Author(s):  
VIRTUE U. EKHOSUEHI ◽  
AUGUSTINE A. OSAGIEDE

In this study, we have applied optimal control theory to determine the optimum value of tax revenues accruing to a state given the range of budgeted expenditure on enforcing tax laws and awareness creation on the payment of the correct tax. This is achieved by maximizing the state's net tax revenue over a fixed time interval subject to certain constraints. By assuming that the satisfaction derived by the Federal Government of Nigeria on the ability of the individual states to generate tax revenue which is as near as the optimum tax revenue (via the state's control problem) is described by the logarithmic form of the Cobb–Douglas utility function, a formula for horizontal revenue allocation in Nigeria in its raw form is derived. Afterwards, we illustrate the use of the proposed horizontal revenue allocation formula using hypothetical data.


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