RU2149438C1 - Method for automatic control of operations of engine - Google Patents

Abstract

FIELD: automatic control equipment using feedback circuit based on wavelet analysis method. SUBSTANCE: method involves converting signals from detectors, which are mounted on engine, by means of computer, wavelet analysis of said signals. Computer judges need to change engine operation mode using analysis of characteristics of wavelet coefficients within specific range. If necessary, computer outputs command through control unit and actuating mechanism performs required regulation. EFFECT: increased reliability. 1 dwg

Description

 The invention relates to automatic control systems, in particular, to controlling the operation of turbines, compressors, periodically operating devices.

 Known methods of controlling the operating mode of engines (Yu.N. Nechaev, PM Fedorov, Theory of aircraft gas turbine engines, M., Mechanical Engineering, 1978, vol. 2, pp. 200-227), developed even at a time when computers were low-power, slow acting and bulky. The disadvantage of these methods is the need for direct human exposure to the engine to change its operating mode, which often leads to erroneous or belated decisions.

 There are also known control methods using adaptive digital systems with full responsibility, which ensure the hydrodynamic stability of the engine and prevent the violation of stable operating modes (Pratt-Whitney). They have a diagnostic unit and are equipped with algorithms for detecting engine failures that allow you to identify malfunctions in certain operating modes and set the sequence of actions necessary to eliminate these malfunctions (CF Simmons, G. Brant, Enhanced fighter engine operability using full authority digital electronic control systems, preprint AIAA-88-3266; translation into "News of foreign science and technology", ser. "Aircraft engine building", M., TsIAM, 1989, issue 6-7, p. 12-19). The disadvantage of these methods is that they analyze only flight conditions and control the operation of the engine, preventing it from reaching its maximum performance, but do not determine possible harbingers of engine malfunction occurring for internal reasons. Due to this adjustment, the interval of possible operating modes of the engine is often greatly limited and its capabilities are not fully used. To create optimal algorithms for such control, a lot of preliminary research work is necessary and, nevertheless, an element of subjectivity in the prescribed algorithms is not excluded.

 Closest to the claimed method in terms of technical nature and the achieved effect is a method of automatically controlling the operation of the engine with a sharp discharge of fuel when self-oscillations of gas occur in the combustion chamber (JH Waters, Digital controller applied to the limitation of reheat combustion roughness, Proc. Of AGARD conference, 1974, N15-1). The disadvantage of this method is the prevention of only already developed vibrations that adversely affect the engine resource, which when large fluctuations really requires a sharp drop in fuel supply, leading to a noticeable change in engine thrust and, often, to undesirable consequences.

 The proposed method is significantly different in that in the process of transmitting the signals of the sensors installed on the engine to the analyzing computing device, a precursor to the engine malfunction is determined in advance using computer wavelet diagnostics, on the basis of which the automatic control system with quick response sends a command to adjust the engine , preventing violations in the mode of its operation.

 The technical task of the invention is the expansion of the range of engine control by increasing the reliability and speed of response of the feedback system both in stationary conditions and during movement under steady and unsteady operating modes, achieved by early detection of precursors of a possible violation of the operating mode and issuing a command for appropriate adjustment .

 The problem is solved by first diagnosing the engine operating mode, consisting in the fact that with the help of sensors installed on a running engine, measure the magnitude and change in time of its physical parameters (vibration, deformation, gas pressure, acoustic noise, etc. .), in the computer unit, these signals are converted into wavelet coefficients, their variances and / or higher correlation matrices are analyzed at different scales, after which, based on their changes over time and the computer algorithms embedded in it the yuter draws conclusions about the need to change the operating mode of the engine and the method for performing this operation, sends the corresponding command to the automatic control system, which adjusts the engine through the actuator. In this way, self-regulation of the engine is achieved.

 The inventive method of automatic control of engine operation is characterized by a high degree of reliability provided by the diagnostic properties using wavelet analysis, the speed and accuracy of computer processing of sensor signals and the issuance of an adjustment command, as well as the multifunctionality of the entire system, when in addition to sensor signals, other information is also processed (for example , flight data in the case of aircraft), and according to the results of their joint processing, many parameters are not selected bhodimye teams to perform specific operations in a series of possible ways to adjust the motor incorporated in the computer. All these features together provide an extension of the range of engine control, unattainable using previously proposed methods.

 The inventive method is illustrated in the drawing in a block diagram. The block diagram consists of an engine 1, a sensor 2 of signals about its operating mode, a measuring device 3, a computer 4, an automatic control system 5 and an actuating device 6. For multi-function aircraft 7 (airplane, satellite, etc.), this block the circuit is supplemented by a device 8, accumulating other information about the device (for example, flight data).

 The method is as follows. The sensor 2 on the engine 1 registers the physical parameters (vibration, deformation, pressure fluctuations, acoustic noises, etc.) of the engine and transmits them to the measuring device 3, converting this data into a set of numbers characterizing the change in the value of the parameters over time at certain intervals time, then this set enters computer 4, which conducts wavelet analysis by calculating the corresponding wavelet coefficients, their dispersion and higher correlation matrices at different scales, and in case of detection their noticeable changes compared with the normal engine operation mode, selects a method for adjusting operation, coordinating it also with flight information, and issues a command to the automatic control system 5, which drives an actuator 6 that changes the engine operation mode according to the received command.

 Taking into account the various physical parameters of the engine and other flight data and the selection of the most adequate way out of many control methods determines the multifunctionality of the method. Its reliability is achieved by repeatedly checking the correctness of the commands issued by the computer, by inter-monitoring the conclusions obtained from the dispersion wavelet analysis and additional higher correlation matrices at different scales. The speed of the method is provided by the locality of the wavelet analysis and the speed of data processing on the computer. The method does not require human intervention.

 The main delay in the feedback block diagram is due to the speed of input, processing and output of information from the computer. It is limited from below not by the speed of the computer, but mainly by the speed of physical processes and the way they are processed and analyzed. The inventive method was carried out on a working compressor of an aircraft gas turbine engine with three modes of operation, when the rotor speed varied from 76 to 81 and 100% of the maximum allowable. According to the measurements, the conversion of the primary signal of the sensor, the wavelet analysis of the data accumulated over a limited time interval, mutual verification of the conclusions obtained as a result of this analysis, and issuing a command to the actuator take about 0.2 s in the method used. Signals from eight sensors were received at intervals of 1 ms. The value of 0.2 s is determined mainly by the rate of the transition from the wavelet dispersion of the normal mode to the dispersion of the precursor, which lasts much longer with this representation. A harbinger of a possible compressor malfunction detected by a computer is that for a sufficiently long time (about 2.5 s at normal load and about 1 s at full load) until the compressor shows disturbances (surge), the wavelet coefficient dispersion at 4- multiple resolution interval at a certain correlation level decreases by 30-40%. It is the duration of this decline and its diagnosis that gives a total value of 0.2 s, much shorter than the duration of the precursors of 1-2.5 s, which allows you to have a large margin of time to confidently begin smooth adjustment of the operating mode. A clear indication of the precursor and its quick recognition are the main advantages of the proposed method, since it is not possible to identify any precursors in other ways for such a long time before the onset of surging.

 Compared with the prototype, this method allows faster and more reliable control, taking into account many parameters without a sharp change in operating mode, which is ensured by effective diagnostics using wavelet analysis of early warning signs of engine deviations and the presence of quick feedback.

 The proposed method can be used to automatically control the operation mode of any regularly (in particular periodically) operating engines with both steady and unsteady operating modes in order to prevent malfunctions and accidents.

Claims (1)

 A method for automatically controlling engine operation using feedback based on computer processing of signals removed from the engine through a sensor, characterized in that during computer processing, the wavelet coefficients of the sensor signals, their dispersions and higher correlation matrices are calculated, they are analyzed, followed by a control command on adjusting the operating mode through the actuator to the engine.