Automatic control method and device for engine bleed valve for unmanned aerial vehicle

Abstract

The invention relates to the technical field of unmanned aerial vehicles, and provides an automatic control method and device for an engine bleed valve for an unmanned aerial vehicle, and the method comprises the steps that the change value of engine performance is determined according to the angle of a guide vane, the change value comprises the compressor outlet pressure, the power turbine inlet total temperature and the power turbine torque, and the angle change of the guide vane in a certain rotating speed interval is called; the method comprises the following steps: acquiring a guide vane angle change of an engine, determining an average change value of engine performance according to the guide vane angle change, calculating to obtain a guide vane angle corresponding to each performance of the engine according to the average change value and the change value, selecting a maximum guide vane angle from the guide vane angles, modifying a reference guide vane angle at the current rotating speed until the maximum guide vane angle is reached; and the deflation valve is automatically closed. Therefore, the problem that the engine state is unstable due to frequent opening and closing of the deflation valve is avoided, and the working stability and reliability of the engine are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of unmanned aerial vehicles, and in particular relates to an automatic control method and device for an engine bleed valve of a unmanned aerial vehicle. Background Art

[0002] The bleed valve is a type of accessory installed on the compressor component of an aircraft engine. Its main function is to release part of the high-pressure gas in the compressor into the atmosphere to improve the engine's surge margin and starting success rate, and prevent surge and starting failure.

[0003] The traditional "switch-type" bleed valve includes two control states: "open" and "closed". Opening and closing are only related to the engine compressor outlet pressure P3 and the ambient atmospheric pressure P0, and are not controlled by the CNC system. Generally, when P3 / P0 is between 0 and A (A is the threshold), the bleed valve is in the open state. At this time, it corresponds to the engine starting process and the lower state, and it is necessary to bleed air to ensure the stable operation of the engine; when P3 / P0 is greater than A, the bleed valve is in the closed state, which corresponds to the higher state of the engine.

[0004] Under normal circumstances, the opening and closing of the bleed valve will not affect the working stability of the engine. However, when the engine is in a certain state for a long time and the P3 / P0 of this state is near A, the bleed valve will open and close frequently, causing the engine state to become unstable. In addition, the frequent impact of high-pressure gas brings additional excitation and vibration, affecting the service life of the bleed valve and the safety of the engine. In order to avoid this situation, in the manned state, the pilot can still judge the state of the bleed valve by combining the somatosensory vibration and parameter interpretation, so as to manually intervene in the engine state and avoid staying in this state for a long time, but too much attention and operation may distract the pilot's attention. In addition, in the unmanned state, after the somatosensory vibration is lost, it is more difficult to distinguish whether the engine instability and vibration abnormality are caused by the bleed valve or other faults, which increases the risk of the test flight in disguise. Summary of the invention

[0005] In view of the above problems, the present invention proposes an automatic control method for an engine bleed valve for a drone, the method comprising:

[0006] Determining the change value of the engine performance according to the guide vane angle, the change value including the compressor outlet pressure, the power turbine inlet total temperature and the power turbine torque;

[0007] Retrieving the change of the guide vane angle within a certain speed range, and determining the average change value of the engine performance according to the change of the guide vane angle, calculating the guide vane angles corresponding to each performance of the engine according to the average change value and the change value, and selecting the maximum guide vane angle therefrom;

[0008] Modify the reference guide vane angle at the current rotational speed until the maximum guide vane angle is reached, and then automatically close the bleed valve.

[0009] Optionally, determine the change value of the engine performance according to the guide vane angle, including:

[0010] Select the reference guide vane angle in a certain rotational speed range;

[0011] Obtain three guide vane angles, including the first negative angle, the reference guide vane angle, and the first positive angle;

[0012] Calculate the first, second, and third selected guide vane angles respectively according to the three guide vane angles and the reference guide vane angle;

[0013] Obtain the corresponding selected engine performance parameters according to the three selected guide vane angles, and each of the selected engine performance parameters includes the selected compressor outlet pressure, the selected total inlet temperature of the power turbine, and the selected torque of the power turbine;

[0014] Calculate the change value of the engine performance according to the selected engine performance parameters corresponding to the three selected guide vane angles.

[0015] Optionally, calculate the change value of the engine performance according to the selected engine performance parameters corresponding to the three selected guide vane angles, including:

[0016] Calculate the corresponding change values of the compressor outlet pressure, the total inlet temperature of the power turbine, and the torque of the power turbine for every 1° increase in the guide vane angle respectively; and

[0017] Calculate the corresponding change values of the compressor outlet pressure, the total inlet temperature of the power turbine, and the torque of the power turbine for every 1° decrease in the guide vane angle respectively.

[0018] Optionally, calculate the corresponding change values of the compressor outlet pressure, the total inlet temperature of the power turbine, and the torque of the power turbine for every 1° increase in the guide vane angle respectively, including:

[0019] Calculate the pressure change value for every 1° increase in the guide vane angle according to the selected compressor outlet pressure corresponding to the first selected guide vane angle and the selected compressor outlet pressure corresponding to the second selected guide vane angle;

[0020] Calculate the total temperature change value for every 1° increase in the guide vane angle according to the selected total inlet temperature of the power turbine corresponding to the first selected guide vane angle and the selected total inlet temperature of the power turbine corresponding to the second selected guide vane angle;

[0021] Calculate the torque change value for every 1° increase in the guide vane angle according to the selected torque of the power turbine corresponding to the first selected guide vane angle and the selected torque of the power turbine corresponding to the second selected guide vane angle.

[0022] Optionally, calculate the corresponding change values of the compressor outlet pressure, the total inlet temperature of the power turbine, and the power turbine torque for each 1° decrease in the guide vane angle, including:

[0023] Calculate the pressure change value for each 1° increase in the guide vane angle based on the recorded compressor outlet pressure corresponding to the third recorded guide vane angle and the recorded compressor outlet pressure corresponding to the second recorded guide vane angle;

[0024] Calculate the total temperature change value for each 1° increase in the guide vane angle based on the recorded total inlet temperature of the power turbine corresponding to the third recorded guide vane angle and the recorded total inlet temperature of the power turbine corresponding to the second recorded guide vane angle;

[0025] Calculate the torque change value for each 1° increase in the guide vane angle based on the recorded power turbine torque corresponding to the third recorded guide vane angle and the recorded power turbine torque corresponding to the second recorded guide vane angle.

[0026] Optionally, retrieve the guide vane angle change within a certain speed range, determine the average change value of the engine performance based on this guide vane angle change, calculate the guide vane angle corresponding to each performance of the engine according to the average change value and the said change values, and before selecting the maximum guide vane angle, including:

[0027] Meet the first condition, preliminarily determine that the bleed valve is opened / closed near the threshold value, and the threshold value is the ratio of the compressor outlet pressure to the ambient atmospheric pressure;

[0028] Meet the second condition, judge whether the bleed valve is in the normally open / closed state;

[0029] Perform an exit operation on the frequently opened / closed state of the bleed valve.

[0030] Optionally, retrieve the guide vane angle change within a certain speed range, determine the average change value of the engine performance based on this guide vane angle change, calculate the guide vane angle corresponding to each performance of the engine according to the average change value and the said change values, and select the maximum guide vane angle, including:

[0031] Obtain the maximum oscillation amplitude of the change value of the engine performance determined by the guide vane angle within a predetermined time respectively, and the maximum oscillation amplitude of the change value includes the compressor outlet pressure, the total inlet temperature of the power turbine, and the power turbine torque;

[0032] Obtain the average value of the current gas generator corrected speed and confirm that the average value is within a certain speed range;

[0033] Retrieve the target degree of increase or decrease of the guide vane angle within a certain speed range, and obtain the average change value of the engine performance according to the target degree.

[0034] Obtain the guide vane angles corresponding to each performance of the engine respectively according to the maximum oscillation amplitude and the average change value, and select the maximum guide vane angle therefrom.

[0035] Optionally, obtaining the guide vane angles corresponding to each performance of the engine respectively according to the maximum oscillation amplitude and the average change value, and selecting the maximum guide vane angle therefrom includes:

[0036] The guide vane angle required to adjust the compressor outlet pressure:

[0037] △P3 * △P3 ngc

[0038] Wherein, △P3 is the compressor outlet pressure value, and △P3 rgc is the average value of the compressor outlet pressure;

[0039] The guide vane angle required to adjust the total inlet temperature of the power turbine:

[0040] △Tt45 * △Tt45 ngc

[0041] Wherein, △Tt45 is the total inlet temperature of the power turbine, and △Tt45 ngc is the average value of the total inlet temperature of the power turbine;

[0042] The guide vane angle required to adjust the power turbine torque:

[0043] △MKP * △MKP ngc

[0044] Wherein, △MKP is the power turbine torque, and △MKP ngc is the average value of the power turbine torque;

[0045] Select the maximum angle value among the three required guide vane angles.

[0046] Optionally, after modifying the reference guide vane angle at the current rotational speed until reaching the maximum guide vane angle, automatically close the bleed valve, including:

[0047] Automatically modify the reference guide vane angle at the current rotational speed, increasing or decreasing it to the maximum guide vane angle;

[0048] According to the maximum guide vane angle, operate the bleed valve to exit the frequently opened / closed state.

[0049] The present invention also provides an automatic control device for a bleed valve of an engine for an unmanned aerial vehicle, including:

[0050] A determination module, configured to determine the change value of the engine performance according to the guide vane angle, and the change value includes the compressor outlet pressure, the total inlet temperature of the power turbine, and the power turbine torque;

[0051] A calculation module, configured to retrieve the guide vane angle change within a certain rotational speed range, determine the average change value of the engine performance based on the guide vane angle change, calculate the guide vane angles corresponding to each performance of the engine according to the average change value and the said change value, and select the maximum guide vane angle therefrom.

[0052] An exit module, configured to modify the reference guide vane angle at the current rotational speed until reaching the said maximum guide vane angle, and then automatically close the bleed valve.

[0053] The present invention has the following advantages compared with the prior art:

[0054] Without modification and manual intervention, the bleed valve, which is only controlled by the ratio (threshold) of the original P3 (exit pressure) / P0 (atmospheric pressure), affects the compressor exit pressure value by finding the maximum guide vane angle. Since the larger the maximum guide vane angle, the greater the corresponding compressor exit pressure, the ratio of P3 / P0 (with P0 unchanged) becomes larger, that is, this ratio is much greater than the original threshold, and the bleed valve will automatically close, thus avoiding the problem of the bleed valve opening and closing frequently, which may lead to the instability of the engine state, and improving the working stability and reliability of the engine. In addition, in the unmanned state, after losing the body sensation vibration, whether it is caused by the bleed valve or other faults leading to engine instability and abnormal vibration, the maximum guide vane angle can be found to affect the compressor exit pressure value and close the bleed valve in time, reducing the flight test risk and improving the safety.

[0055] Other features and advantages of the present invention will be described in the following specification, and some of them will become obvious from the specification or be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures pointed out in the specification and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0057] Figure 1 It shows a schematic flow diagram of the automatic control method for the bleed valve of the engine used in the unmanned aerial vehicle in the embodiment of the present invention;

[0058] Figure 2 It shows a schematic diagram of the automatic control device for the bleed valve of the engine used in the unmanned aerial vehicle in the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0059] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0060] As Figure 1 shown, the present invention provides an automatic control method for an engine bleed valve of an unmanned aerial vehicle, and the method includes:

[0061] Step S10, determining the change value of the engine performance according to the guide vane angle, and the change value includes the compressor outlet pressure, the total temperature at the inlet of the power turbine, and the power turbine torque. It should be noted that the guide vane angle of a turboshaft engine is adjusted according to the corrected speed of the gas generator. As the speed increases, the opening of the guide vane becomes larger, the flow rate becomes larger, and the corresponding guide vane angle decreases. At the same corrected speed, the power is larger. The corresponding relationship is shown as follows:

[0062] Table 1 shows the corresponding relationship between the guide vane angle and ngc (corrected speed of the gas generator)

[0063]

[0064] According to experience, in different guide vane intervals, the influence of the same change in the guide vane angle on the engine performance is different. For example, in the range of 85% ngc to 90% ngc and in the range of 95% ngc to 100% ngc, when the guide vane angle changes by 1°, there are certain differences in the influence on typical parameters such as P3 (compressor outlet pressure), Tt45 (total temperature at the inlet of the power turbine), and Mkp (power turbine torque). Therefore, the influence of the guide vane angle on the engine performance in different regions is only applicable to a certain speed interval. According to experience, 85% ngc is applicable to 82.5% to 87.5% ngc, 90% ngc is applicable to 87.5% to 92.5% ngc, and so on. In addition, since there are also certain differences in the influence of the increase and decrease of the guide vane on the engine performance, it is necessary to determine the change value of the engine performance. The change value includes the compressor outlet pressure, the total temperature at the inlet of the power turbine, and the power turbine torque values when the guide vane angle increases by 1°.

[0065] Step S20, retrieve the change of the guide vane angle within a certain rotational speed range, determine the average change value of the engine performance based on the change of the guide vane angle, calculate the guide vane angles corresponding to each performance of the engine according to the average change value and the change value, and select the maximum guide vane angle therefrom. It should be noted that the average change value of the engine performance is the average change value corresponding to a certain rotational speed range. Among them, the average change value of the engine performance can be obtained by finding multiple change values of the engine performance within a predetermined time, adding these change values of the engine performance and dividing by the total number of change values of the engine performance. For example, within 10 seconds, 100 compressor outlet pressures, total inlet temperatures of the power turbine, or power turbine torques are selected within a certain rotational speed range. Add these 100 different compressor outlet pressures, total inlet temperatures of the power turbine, or power turbine torques respectively and divide each by 100 to obtain their respective average values. This average value is the average change value of the guide vane angle change on the engine performance within a certain rotational speed range.

[0066] Step S30, modify the reference guide vane angle at the current rotational speed until the maximum guide vane angle is reached, and then automatically close the bleed valve. It should be noted that the larger the guide vane angle, the greater the flow rate, that is, the greater the compressor outlet pressure, and it is easier to automatically close the bleed valve. That is, since P0 remains unchanged and the compressor outlet pressure P3 changes, the ratio of P3 / P0 now is much greater than the threshold value obtained from the original P3 / P0 ratio, and the bleed valve will automatically close. Thus, automatic diagnosis and adaptive adjustment of the engine are achieved, quickly exiting the dangerous state, and improving the working stability and reliability of the engine. In addition, even in the unmanned state, the present application can close the bleed valve in this way. That is, in the unmanned state, after losing the body sensation vibration, regardless of whether it is caused by the bleed valve or other faults leading to engine instability and abnormal vibration, the maximum guide vane angle can be found, affecting the compressor outlet pressure value to close the bleed valve in time, reducing the flight test risk and improving the safety.

[0067] In one embodiment, determining the change value of the engine performance according to the guide vane angle includes:

[0068] Select the reference guide vane angle in a certain speed range. As shown in Table 1, the reference guide vane angle within the 95% ngc range can be selected. Obtain three guide vane angles, including the first negative angle -5°, the reference guide vane angle 6°, and the first positive angle +5°. Calculate the first, second, and third selected guide vane angles respectively according to the three guide vane angles and the reference guide vane angle. These three angles are 11°, 6°, and 1° in sequence. 11° is obtained by adding the first positive angle +5° to the reference guide vane angle 6°, and 1° is obtained by adding the first negative angle -5° to the reference guide vane angle 6°. Obtain the corresponding selected engine performance parameters according to the three selected guide vane angles. Each selected engine performance parameter includes the selected compressor outlet pressure, the selected total inlet temperature of the power turbine, and the selected power turbine torque, that is, the values corresponding to the guide vane angle up to 11° for the selected engine performance are P3 95％-11 、Tt45 95％-11 、Mkp 95％-11 , the values corresponding to the guide vane angle 6° for the selected engine performance are P3 95％-6 、Tt45 95％-6 、Mkp 95％-6 , the values corresponding to the guide vane angle 1° for the selected engine performance are P3 95％-1 、Tt45 95％-1 、Mkp 95％-1 , calculate the change value of the engine performance according to the selected engine performance parameters corresponding to the three selected guide vane angles.

[0069] In one embodiment, calculate the change value of the engine performance according to the selected engine performance parameters corresponding to the three selected guide vane angles, including:

[0070] Since there are also certain differences in the influence of the increase and decrease of the guide vane angle on the engine performance, first calculate the influence of the guide vane angle increasing by 1° and the guide vane angle decreasing by 1° respectively.

[0071] Calculate the corresponding change values of the compressor outlet pressure, the total inlet temperature of the power turbine, and the power turbine torque for each 1° increase in the guide vane angle respectively;

[0072] Calculate the corresponding change values of the compressor outlet pressure, the total inlet temperature of the power turbine, and the power turbine torque for each 1° decrease in the guide vane angle respectively.

[0073] In one embodiment, calculate the corresponding change values of the compressor outlet pressure, the total inlet temperature of the power turbine, and the power turbine torque for each 1° increase in the guide vane angle respectively, including:

[0074] Select the 95% ngc range as an example for illustration:

[0075] Calculate the pressure change value for every 1° increase in the guide vane angle based on the compressor outlet pressure corresponding to the first intake guide vane angle and the compressor outlet pressure corresponding to the second intake guide vane angle. Specifically as follows:

[0076]

[0077] Calculate the total temperature change value for every 1° increase in the guide vane angle based on the total inlet temperature of the power turbine corresponding to the first intake guide vane angle and the total inlet temperature of the power turbine corresponding to the second intake guide vane angle. Specifically as follows:

[0078]

[0079] Calculate the torque change value for every 1° increase in the guide vane angle based on the power turbine torque corresponding to the first intake guide vane angle and the power turbine torque corresponding to the second intake guide vane angle. Specifically as follows:

[0080]

[0081] It should be noted that the above are all divided by 5 to obtain the first positive angle.

[0082] In one embodiment, calculate the corresponding change values of the compressor outlet pressure, the total inlet temperature of the power turbine, and the power turbine torque for every 1° decrease in the guide vane angle respectively, including:

[0083] Select the 95% ngc interval as an example for illustration:

[0084] Calculate the pressure change value for every 1° increase in the guide vane angle based on the compressor outlet pressure corresponding to the third intake guide vane angle and the compressor outlet pressure corresponding to the second intake guide vane angle. Specifically as follows:

[0085]

[0086] Calculate the total temperature change value for every 1° increase in the guide vane angle based on the total inlet temperature of the power turbine corresponding to the third intake guide vane angle and the total inlet temperature of the power turbine corresponding to the second intake guide vane angle. Specifically as follows:

[0087]

[0088] Calculate the torque change value for every 1° increase in the guide vane angle based on the power turbine torque corresponding to the third intake guide vane angle and the power turbine torque corresponding to the second intake guide vane angle. Specifically as follows:

[0089]

[0090] In one embodiment, before retrieving the guide vane angle change within a certain rotational speed range, determining the average change value of the engine performance based on the guide vane angle change, calculating the guide vane angle corresponding to each performance of the engine according to the average change value and the change value, and selecting the maximum guide vane angle therefrom, the following steps are included:

[0091] When the first condition is met, it is preliminarily determined that the bleed valve is opened / closed near the threshold value, where the threshold value is the ratio of the compressor outlet pressure to the ambient atmospheric pressure. It should be noted that the threshold value is the ratio of P3 / P0 and is fixed. As long as the bleed valve opens / closes frequently near the threshold value, that is, when the engine state is stable. Therefore, the prerequisite conditions for judging the frequent opening / closing of the bleed valve are as shown in Table 2 below:

[0092] Table 2:

[0093] parameter fluctuation quantity LDL not greater than ±1° T1 not greater than ±5℃ P1 not greater than ±5%

[0094] In Table 2, LDL is the engine load lever angle, T1 is the engine inlet temperature, and P1 is the engine inlet pressure.

[0095] When the second condition is met, it is judged whether the bleed valve is in the normally open / closed state. It should be noted that when the bleed valve changes from closed to open, it will cause some high-pressure gas at the compressor outlet to be lost, the compressor outlet pressure will decrease, and the engine's work capacity will decline. Since the load lever LDL remains unchanged, in order to generate the same power, the numerical control system will increase the fuel supply. When the bleed valve changes from open to closed, it will reduce the loss of high-pressure gas at the compressor outlet, the compressor outlet pressure will rise, and the engine's work capacity will recover. Since the load lever remains unchanged, in order to generate the same power, the numerical control system will reduce the fuel supply. Frequent opening / closing of the bleed valve will cause the engine vibration to increase.

[0096] Specifically, it is necessary to meet the fluctuating energy in Table 3 below and the oscillation frequency is not less than 3 times per second to judge whether the bleed valve is in the normally open / closed state.

[0097] Table 3 below

[0098]

[0099] Fz-ng is the fundamental frequency vibration of the gas generator rotor. If it meets the condition of increasing by 50% on the basis of the original vibration amplitude or being greater than 80% of the Fz-ng limit value (upper limit value), then it is judged that the bleed valve is in the normally open / closed state.

[0100] Perform an exit operation on the frequent opening / closing state of the bleed valve.

[0101] In one embodiment, the guide vane angle change within a certain speed range is retrieved, and the average change value of the engine performance is determined according to the guide vane angle change. According to the average change value and the change value, the guide vane angles corresponding to each performance of the engine are calculated, and the maximum guide vane angle is selected from them, including:

[0102] Within a predetermined time, the maximum oscillation amplitude of the change value of the engine performance determined by the guide vane angle is respectively obtained. The maximum oscillation amplitude of the change value includes the compressor outlet pressure, the total inlet temperature of the power turbine, and the power turbine torque. Specifically, the maximum oscillation amplitudes △P3, △Tt45, and △Mkp of the relevant parameters are captured within 10 seconds. The maximum oscillation amplitude is calculated by the difference between the respective maximum value and minimum value.

[0103] Obtain the average value of the current gas generator corrected speed and confirm that the average value is within a certain speed range. Specifically, the average value of the gas generator corrected speed is obtained by dividing the total speed obtained within 10 seconds by 100. Among them, 10 different speed points can be obtained within 1 second, and 100 are obtained within 10 seconds.

[0104] Confirm that the target degree of increase or decrease of the guide vane angle within a certain speed range is retrieved, and the average change value of the engine performance is obtained according to the target degree. Specifically, it can be known from Table 1 which speed range in Table 1 it is in. Retrieve the change value of the performance when the guide vane angle increases by 1° within the relevant speed range. By finding their respective quantities within 10 seconds in this speed range and adding them up and dividing by the total number, the average change value of the corresponding engine performance is obtained. For example, at the 95% ngc state, 100 different compressor outlet pressures are found within 10 seconds, and the sum obtained by adding them up is divided by 100, and finally the average value of the compressor outlet pressure is obtained. The same is true for the other two parameters and will not be further described.

[0105] According to the maximum oscillation amplitude and the average change value, the guide vane angles corresponding to each performance of the engine are obtained, and the maximum guide vane angle is selected from them.

[0106] In one embodiment, according to the maximum oscillation amplitude and the average change value, the guide vane angles corresponding to each performance of the engine are obtained, and the maximum guide vane angle is selected from them, including:

[0107] The guide vane angle required to adjust the compressor outlet pressure:

[0108] △P3 * △P3 ngc

[0109] Wherein, △P3 is the compressor outlet pressure value, and △P3 rgc is the average value of the compressor outlet pressure;

[0110] The guide vane angle required to adjust the total inlet temperature of the power turbine:

[0111] △Tt45 * △Tt45 ngc

[0112] Among them, △Tt45 is the total inlet temperature of the power turbine, and △Tt45 ngc is the average value of the total inlet temperature of the power turbine;

[0113] The guide vane angle required to adjust the power turbine torque:

[0114] △MKP * △MKP ngc

[0115] Among them, △MKP is the power turbine torque, and △MKP ngc is the average value of the power turbine torque;

[0116] Select the maximum angle value among the three required guide vane angles. The guide vane angle required to restore to the normal state is obtained through the above calculations. Thus, the compressor outlet pressure value is affected according to the selected maximum angle value, and further, the bleed valve will automatically close, avoiding the problem of the bleed valve opening and closing frequently, which may lead to the instability of the engine state, and improving the working stability and reliability of the engine. Taking the guide vane angle required to adjust the compressor outlet pressure as an example, and taking the 95% ngc interval as an example for illustration: △P3 * △P3 ngc According to calculate respectively, where 5 is 5°, and then according to this formula, △P3 * △P3 can be obtained ng The corresponding degree. Similarly, the guide vane angle required for the total inlet temperature of the power turbine and the guide vane angle required for the power turbine torque are also obtained through such calculations. Specifically, taking 90% ngc as an example, the influence of the guide vane angle increasing by 1° is:

[0117] △P3 90％+ =-2% / °

[0118] △Tt 4590％+ =-4℃ / °

[0119] △MKP 90％+ =-1.5% / °

[0120] The influence of the guide vane angle decreasing by 1° is:

[0121] △P3 90％- =2% / °

[0122] △Tt45 90％- =4℃ / °

[0123] △MKP 90％- =1.5% / °

[0124] Step 2: During the process of the engine being pulled down from a large state, the bleed valve opens and closes frequently near 91% ngc, with an oscillation frequency of 5. At this time, the maximum oscillation amplitudes of the three parameters are as follows:

[0125] △P3: is 4%

[0126] △Tt45: is 12 °C

[0127] △Mkp: is 6%

[0128] Fz-ng: the vibration amplitude suddenly increases by 70%

[0129] It can be seen from this method that the engine is in the interval where the bleed valve opens and closes frequently based on the above data.

[0130] Since 90% ngc is applicable to 87.5% - 92.5%, therefore, the guide vane change characteristics of 90% ngc can be used for 91% ngc. Since the engine is pulled down from a large state, that is, ng changes from high to low, it is considered that the operator wants to reduce the engine state, and the required increased angles of the three parameters are respectively:

[0131] The guide vane angle required to adjust P3: 4% ÷ -2% / ° = -2°

[0132] The guide vane angle required to adjust Tt45: 12 °C ÷ -4 °C / ° = -3°

[0133] The guide vane angle required to adjust MKP: 6% ÷ -1.5% / ° = -4°

[0134] As can be seen from the above, if you want to exit the frequently opening / closing interval, the maximum adjusted guide vane angle is -4°, that is, the guide vane angle increases by 4°.

[0135] In one embodiment, after modifying the reference guide vane angle at the current speed until the maximum guide vane angle is reached, the bleed valve is automatically closed, including:

[0136] Automatically modify the reference guide vane angle at the current speed, increasing or decreasing to the maximum guide vane angle;

[0137] According to the maximum guide vane angle, operate the bleed valve to exit the frequently opening / closing state.

[0138] Specifically, if the diagnosis that the bleed valve opens and closes frequently is true, and Ng (speed) changes from high to low. Then it is considered that the operator wants to reduce the engine state, and the change values of the engine performance when the guide vane angle increases by 1° in the relevant speed range are retrieved: ΔP3 ngc+ 、ΔMKP ngc+ 、Tt45 ngc+ , and calculate the guide vane angles required to adjust each parameter to return to the normal state according to the following method:

[0139] Adjust the guide vane angle required for P3: ΔP3×ΔP3 ngc+

[0140] Adjust the guide vane angle required for Tt45: ΔTt45×Tt45 ngc+

[0141] Adjust the guide vane angle required for MKP: ΔMKP×ΔMKP ngc+ .

[0142] The larger of the above three calculated values is defined as C°. In order to exit the dangerous state of frequent opening / closing as soon as possible, the CNC system automatically modifies the reference guide vane angle at the current speed and slowly increases it to C°

[0143] Furthermore, if the diagnosis of the frequent opening / closing of the bleed valve is true, and Ng changes from low to high, it is considered that the operator wants to improve the engine state, and the change value of the engine performance caused by reducing the guide vane angle by 1° in the relevant speed range is retrieved: ΔP3 ngc- , ΔMKP ngc- 、Tt45 ngc- , and calculate the guide vane angle that needs to be adjusted to restore each parameter to normal state as follows:

[0144] Adjust the angle required for P3: ΔP3×ΔP3 ngc-

[0145] Adjust the angle required for Tt45: ΔTt45×Tt45 ngc-

[0146] Adjust the angle required for MKP: ΔMKP×ΔMKP ngc-

[0147] The larger of the above three calculated values is defined as D°. In order to exit the dangerous state of frequent opening / closing as soon as possible, the CNC system automatically modifies the reference guide vane angle at the current speed and slowly decreases it to D°.

[0148] The bleed valve will automatically close through the above method, thus avoiding the problem of engine instability caused by frequent opening and closing of the bleed valve, and improving the stability and reliability of engine operation. In addition, in the unmanned state, after the body vibration is lost, regardless of whether the engine instability and vibration abnormality are caused by the bleed valve or other faults, the bleed valve can be closed in time by finding the maximum guide vane angle, affecting the compressor outlet pressure value, reducing the risk of test flight and improving safety.

[0149] like Figure 2 As shown, the present invention also provides an automatic control device for an engine bleed valve for a drone, comprising:

[0150] A determination module, configured to determine a change value of the engine performance according to the guide vane angle, where the change value includes the compressor outlet pressure, the total inlet temperature of the power turbine, and the power turbine torque;

[0151] A calculation module, configured to retrieve the change of the guide vane angle within a certain rotational speed range, and determine the average change value of the engine performance according to the change of the guide vane angle. According to the average change value and the change value, calculate the guide vane angles corresponding to each performance of the engine respectively, and select the maximum guide vane angle therefrom;

[0152] An exit module, configured to modify the reference guide vane angle at the current rotational speed until the maximum guide vane angle is reached, and then automatically close the bleed valve. Through these modules, the bleed valve can be automatically closed, thus avoiding the problem that the bleed valve is frequently opened and closed, resulting in the instability of the engine state, and improving the working stability and reliability of the engine. In addition, in the unmanned state, after the body sensation vibration is lost, whether it is caused by the bleed valve or other faults that cause the engine instability and abnormal vibration, the maximum guide vane angle can be found to affect the compressor outlet pressure value and timely close the bleed valve, reducing the test flight risk and improving the safety.

[0153] Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An automatic control method for an engine bleed air valve of an unmanned aerial vehicle, characterized in that The method includes: Determining the change value of the engine performance according to the guide vane angle, where the change value includes the compressor outlet pressure, the total inlet temperature of the power turbine, and the power turbine torque; Retrieving the change of the guide vane angle within a certain speed range, and determining the average change value of the engine performance according to the change of the guide vane angle. According to the average change value and the change value, calculating the guide vane angles corresponding to each performance of the engine respectively, and selecting the maximum guide vane angle therefrom; Modifying the reference guide vane angle at the current speed until reaching the maximum guide vane angle, and then automatically closing the bleed valve.

2. The automatic control method for the engine bleed air valve of a drone according to claim 1, wherein Determining the change value of the engine performance according to the guide vane angle, including: Optionally selecting the reference guide vane angle within a certain speed range; Obtaining three guide vane angles, including the first negative angle, the reference guide vane angle, and the first positive angle; Calculating the first, second, and third selected guide vane angles respectively according to the three guide vane angles; Obtaining the corresponding selected engine performance parameters according to the three selected guide vane angles, and each of the selected engine performance parameters includes the selected compressor outlet pressure, the selected total inlet temperature of the power turbine, and the selected power turbine torque; Calculating the change value of the engine performance according to the selected engine performance parameters corresponding to the three selected guide vane angles.

3. The automatic control method for the engine bleed air valve of a drone according to claim 2, wherein Calculating the change value of the engine performance according to the selected engine performance parameters corresponding to the three selected guide vane angles, including: Calculating the corresponding change values of the compressor outlet pressure, the total inlet temperature of the power turbine, and the power turbine torque for each 1° increase in the guide vane angle respectively; and Calculating the corresponding change values of the compressor outlet pressure, the total inlet temperature of the power turbine, and the power turbine torque for each 1° decrease in the guide vane angle respectively.

4. The automatic control method for the engine bleed air valve of a drone according to claim 3, characterized in that, Calculating the corresponding change values of the compressor outlet pressure, the total inlet temperature of the power turbine, and the power turbine torque for each 1° increase in the guide vane angle respectively, including: Calculating the pressure change value for each 1° increase in the guide vane angle according to the selected compressor outlet pressure corresponding to the first selected guide vane angle and the selected compressor outlet pressure corresponding to the second selected guide vane angle; Calculating the total temperature change value for each 1° increase in the guide vane angle according to the selected total inlet temperature of the power turbine corresponding to the first selected guide vane angle and the selected total inlet temperature of the power turbine corresponding to the second selected guide vane angle; Calculating the torque change value for each 1° increase in the guide vane angle according to the selected power turbine torque corresponding to the first selected guide vane angle and the selected power turbine torque corresponding to the second selected guide vane angle.

5. The automatic control method of the engine bleed air valve for an unmanned aerial vehicle according to claim 3, characterized in that Calculating the corresponding change values of the compressor outlet pressure, the total inlet temperature of the power turbine, and the power turbine torque for each 1° decrease in the guide vane angle respectively, including: Calculating the pressure change value for each 1° increase in the guide vane angle according to the selected compressor outlet pressure corresponding to the third selected guide vane angle and the selected compressor outlet pressure corresponding to the second selected guide vane angle; Calculating the total temperature change value for each 1° increase in the guide vane angle according to the selected total inlet temperature of the power turbine corresponding to the third selected guide vane angle and the selected total inlet temperature of the power turbine corresponding to the second selected guide vane angle; Calculate the torque change value for every 1° increase in the guide vane angle based on the admission power turbine torque corresponding to the third admission guide vane angle and the admission power turbine torque corresponding to the second admission guide vane angle.

6. The automatic control method for the engine bleed air valve of an unmanned aerial vehicle according to claim 1, wherein, Retrieve the change in the guide vane angle within a certain speed range, determine the average change value of the engine performance based on this change in the guide vane angle, and calculate the guide vane angles corresponding to each performance of the engine according to the average change value and the said change value, and before selecting the maximum guide vane angle, it includes: Meet the first condition, preliminarily determine that the bleed valve is opened / closed near the threshold value, and the threshold value is the ratio of the compressor outlet pressure to the ambient atmospheric pressure; Meet the second condition, judge whether the bleed valve is in the normally open / closed state; Perform an exit operation on the frequently opened / closed state of the bleed valve.

7. The automatic control method for the engine bleed air valve of an unmanned aerial vehicle according to claim 1, characterized in that Retrieve the change in the guide vane angle within a certain speed range, determine the average change value of the engine performance based on this change in the guide vane angle, and calculate the guide vane angles corresponding to each performance of the engine according to the average change value and the said change value, and select the maximum guide vane angle, including: Obtain the maximum oscillation amplitude of the change value of the engine performance determined by the guide vane angle respectively within a predetermined time, and the maximum oscillation amplitude of this change value includes the compressor outlet pressure, the total inlet temperature of the power turbine, and the power turbine torque; Obtain the average value of the current gas generator corrected speed and confirm that this average value is within a certain speed range; Retrieve the target degree of increase or decrease in the guide vane angle within a certain speed range, and obtain the average change value of the engine performance according to the target degree; Obtain the guide vane angles corresponding to each performance of the engine according to the maximum oscillation amplitude and the average change value, and select the maximum guide vane angle from them.

8. The automatic control method for the engine bleed air valve of an unmanned aerial vehicle according to claim 7, characterized in that, Obtain the guide vane angles corresponding to each performance of the engine according to the maximum oscillation amplitude and the average change value, and select the maximum guide vane angle from them, including: The guide vane angle required to adjust the compressor outlet pressure: △P3 * △P3 ngc wherein, △P3 is the compressor outlet pressure value, and △P3 rgc is the average value of the compressor outlet pressure; The guide vane angle required to adjust the total inlet temperature of the power turbine: △Tt45*△Tt45 ngc where, △Tt45 is the total inlet temperature of the power turbine, and △Tt45 ngc is the average value of the total inlet temperature of the power turbine; The guide vane angle required to adjust the power turbine torque: △MKP*△MKP ngc where, △MKP is the torque of the power turbine, △MKP ngc is the average value of the torque of the power turbine; Select the maximum angle value among the three required guide vane angles.

9. The automatic control method for the engine bleed air valve of a drone according to claim 1, characterized in that, Modify the reference guide vane angle at the current speed until reaching the said maximum guide vane angle, and then automatically close the bleed valve, including: Automatically modify the reference guide vane angle at the current speed, increasing or decreasing to the said maximum guide vane angle; According to the maximum guide vane angle, operate the bleed valve to exit the frequently opened / closed state.

10. An automatic control device for an engine bleed air valve of a drone, characterized in that, It includes: A determination module, used to determine the change value of the engine performance according to the guide vane angle, and this change value includes the compressor outlet pressure, the total inlet temperature of the power turbine, and the power turbine torque; A calculation module, used to retrieve the change in the guide vane angle within a certain speed range, determine the average change value of the engine performance based on this change in the guide vane angle, calculate the guide vane angles corresponding to each performance of the engine according to the average change value and the said change value, and select the maximum guide vane angle from them; An exit module, used to modify the reference guide vane angle at the current speed until reaching the said maximum guide vane angle, and then automatically close the bleed valve.

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