Single-shot unmanned helicopter engine power turbine overspeed protection method and system

Abstract

The present application provides a single-shot unmanned helicopter engine power turbine overspeed protection method and system, including the steps: analyzing the power turbine acceleration rate to determine the power turbine rotor trend; analyzing the engine control stick angle trend to determine the energy supply trend; judging the engine state based on the power turbine rotor trend and the energy supply trend; determining the fault condition according to the engine state; detecting whether the fault condition reaches the threshold value; when the fault condition reaches the threshold value, taking protective measures. The present application allows to appropriately release the power turbine overspeed protection speed for a short time on the basis that the power turbine rotor has the ability to work for 5 minutes at the overspeed protection speed and has the ability to work for 30 seconds at the rupture speed; unlike the fixed speed overspeed protection logic of the original technology, the fault condition is flexibly adjusted, the specific value of the power turbine speed protection value is changed, and different overspeed protection strategies are developed for different working environments.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of engine overspeed protection, and particularly relates to a single-engine unmanned helicopter engine power turbine overspeed protection method and system. BACKGROUND

[0002] At present, aiming at the dangerous state of the aviation engine power turbine overspeed state, the numerical control system of the aviation engine engine is provided with a "power turbine overspeed protection function", that is, when the power turbine speed reaches the power turbine speed protection value, the control system immediately cuts off the oil and stops the engine, which can indeed play an effective protection role for the single-engine manned helicopter or multi-engine helicopter by adopting the above overspeed protection method.

[0003] However, for the unmanned single-engine helicopter, this measure may not be applicable. After the single-engine manned helicopter engine overspeed stops, the pilot can take correct and objective measures according to the flight height, attitude, environment and the like, such as selecting air restart or autorotation descent, which can still effectively ensure flight safety. However, the single-engine unmanned helicopter lacks a pilot to drive, and once the engine overspeed protection stops, the helicopter will lose power, and it is difficult for the ground operator to intuitively feel the attitude and flight environment of the helicopter, so it is difficult to take objective and correct measures, increasing the risk of test flight. At the same time, the way of judging by the power turbine speed reaching the fixed power turbine speed protection value cannot meet the complex and diverse flight environment, and on the basis of the low maneuverability caused by the lack of in-flight pilots of the unmanned helicopter, the protection problem of the single-engine unmanned helicopter in the engine power turbine overspeed state is further aggravated. SUMMARY

[0004] In view of the above problems, the application provides a single-engine unmanned helicopter engine power turbine overspeed protection method, which comprises the following steps:

[0005] analyzing the power turbine acceleration rate to determine the change trend of the power turbine rotor;

[0006] analyzing the change trend of the engine control lever angle to determine the energy supply trend;

[0007] judging the engine state based on the change trend of the power turbine rotor and the energy supply trend;

[0008] determining the fault condition according to the engine state;

[0009] detecting whether the fault condition reaches a threshold value;

[0010] when the fault condition reaches the threshold value, taking a protection measure.

[0011] Further, in the step of analyzing the power turbine acceleration rate to determine the change trend of the power turbine rotor,

[0012] When the power turbine acceleration rate is less than or equal to the maximum acceleration rate of the power turbine in normal engine operation, it indicates that the power turbine rotor change trend is normal;

[0013] When the power turbine acceleration rate is greater than or equal to the product of the maximum acceleration rate of the power turbine in normal engine operation and the margin coefficient, it indicates that the power turbine rotor change trend is abnormal.

[0014] Further, in the determination of the energy supply trend based on the engine control lever angle change trend, the engine control lever angle change trend includes: an acceleration push trend and a deceleration pull trend;

[0015] The acceleration push trend indicates that the energy supply trend is a state of gradually increasing fuel supply;

[0016] The deceleration pull trend indicates that the energy supply trend is a state of gradually decreasing fuel supply.

[0017] Further, in the determination of the fault condition based on the engine state;

[0018] When the power turbine rotor change trend is normal, and the energy supply trend is a state of gradually increasing fuel supply or a state of gradually decreasing fuel supply, the fault condition is that the power turbine speed is greater than or equal to the power turbine speed protection value after an increase of 5%;

[0019] When the power turbine rotor change trend is abnormal, and the energy supply trend is a state of gradually increasing fuel supply or a state of gradually decreasing fuel supply, the fault condition is that the power turbine speed is greater than or equal to the power turbine speed protection value.

[0020] Further, when the power turbine rotor change trend is normal, and the energy supply trend is a state of gradually increasing fuel supply, the gas generator speed limit value, the power turbine inlet temperature limit value, and the power turbine torque limit value are increased;

[0021] When the power turbine rotor change trend is abnormal, and the energy supply trend is a state of gradually decreasing fuel supply, the gas generator speed limit value, the power turbine inlet temperature limit value, and the power turbine torque limit value are decreased.

[0022] Further, the protection measures are engine shutdown and control channel switching.

[0023] The application further provides a single-shot unmanned helicopter engine power turbine overspeed protection system, comprising:

[0024] A first analysis unit is configured to analyze the power turbine acceleration rate to determine the power turbine rotor change trend;

[0025] A second analysis unit is configured to analyze the engine control lever angle change trend to determine the energy supply trend;

[0026] a judging unit configured to judge the engine state based on the power turbine rotor variation trend and the energy supply trend;

[0027] a determining unit configured to determine the fault condition according to the engine state;

[0028] a detecting unit configured to detect whether the fault condition reaches a threshold value;

[0029] a measure unit configured to take a protection measure when the fault condition reaches the threshold value.

[0030] Further, the power turbine acceleration rate is analyzed to determine the power turbine rotor variation trend,

[0031] when the power turbine acceleration rate is less than or equal to the maximum acceleration rate of the power turbine under normal engine operation, it indicates that the power turbine rotor variation trend is normal;

[0032] when the power turbine acceleration rate is greater than or equal to the product of the maximum acceleration rate of the power turbine under normal engine operation and a margin coefficient, it indicates that the power turbine rotor variation trend is abnormal.

[0033] Further, the engine control lever angle variation trend is analyzed to determine the energy supply trend, the engine control lever angle variation trend including: an acceleration push trend, a deceleration pull trend,

[0034] the acceleration push trend indicates that the energy supply trend is a gradually increasing fuel supply amount state;

[0035] the deceleration pull trend indicates that the energy supply trend is a gradually decreasing fuel supply amount state.

[0036] Further, the fault condition is determined according to the engine state,

[0037] when the power turbine rotor variation trend is normal and the energy supply trend is the gradually increasing fuel supply amount state or the gradually decreasing fuel supply amount state, the fault condition is that the power turbine speed is greater than or equal to the power turbine speed protection value after an increase of 5%;

[0038] when the power turbine rotor variation trend is abnormal and the energy supply trend is the gradually increasing fuel supply amount state or the gradually decreasing fuel supply amount state, the fault condition is that the power turbine speed is greater than or equal to the power turbine speed protection value.

[0039] The present invention relates to a method and system for overspeed protection of a single-engine unmanned helicopter engine's power turbine. Based on the power turbine rotor's ability to operate at the overspeed protection speed for 5 minutes and at the burst speed for 30 seconds, it allows for a short-term release of the power turbine's overspeed protection speed. Unlike the fixed-speed overspeed protection logic of existing technologies, this method flexibly adjusts fault conditions and changes the specific value of the power turbine speed protection value based on the trends of engine control stick angle changes and power turbine acceleration rate changes. Different overspeed protection strategies are formulated for different operating environments, allowing the helicopter to gain power output and flight time in emergency situations, ensuring flight safety, and filling the gap in the lack of overspeed protection methods for single-engine unmanned helicopters.

[0040] Meanwhile, the overspeed protection strategy takes into account the overall adjustment of the gas generator speed limit, the power turbine inlet temperature limit, the power turbine torque limit, and the power turbine speed protection value. By adjusting upward and downward, it allows for short-term changes to the above limit values, so as to achieve the purpose of adjusting the engine status more quickly. It further provides contingency plans for emergency situations in flight and adapts to actual flight conditions.

[0041] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 A flowchart of the overspeed protection method for the power turbine of a single-engine unmanned helicopter in an embodiment of the present invention is shown;

[0044] Figure 2 A schematic diagram of the framework of the overspeed protection system for the power turbine of a single-engine unmanned helicopter is shown in an embodiment of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] In response to the dangerous state of over-spinning of the power turbine of a single-engine unmanned helicopter, and considering that the power turbine rotor has the ability to operate for 5 minutes at the over-spinning protection speed and 30 seconds at the bursting speed, this invention provides a method and system for over-spinning protection of the power turbine of a single-engine unmanned helicopter engine to minimize the probability of over-spinning protection shutdown while ensuring flight safety.

[0047] Figure 1 A flowchart of a single-engine unmanned helicopter engine power turbine overspeed protection method according to an embodiment of the present invention is shown. Figure 1 The method for protecting the overspeed of a single-engine unmanned helicopter's power turbine includes the following steps:

[0048] Step S101: Analyze the acceleration rate of the power turbine to determine the trend of the power turbine rotor change;

[0049] Step S102: Analyze the trend of engine control lever angle change to determine energy supply trend;

[0050] Step S103: Determine the engine status based on the changing trend of the power turbine rotor and the energy supply trend;

[0051] Step S104: Determine the fault conditions based on the engine status;

[0052] Step S105: Detect whether the fault condition has reached a threshold;

[0053] Step S106: When the fault condition reaches the threshold, protective measures are taken.

[0054] The engine control stick angle and turbine acceleration rate can be directly obtained from sensors inside the UAV. In particular, when a problem occurs with the helicopter engine turbine, the trend of the engine control stick angle change can indirectly indicate whether the problem has been addressed. The specific protective measures include engine shutdown and control channel switching.

[0055] In the specific application of the method, when analyzing the acceleration rate of the power turbine to determine the trend of the power turbine rotor change, it is possible to judge whether the trend of the power turbine rotor change is normal or not.

[0056] When the acceleration rate of the power turbine is less than or equal to the maximum acceleration rate of the power turbine during normal engine operation, it indicates that the trend of the power turbine rotor change is normal, that is:

[0057] V ≤ V-max (1)

[0058] In the formula, V represents the acceleration rate of the power turbine, in % / s, and V-max is the maximum acceleration rate of the power turbine under normal operating conditions such as engine start-up and rapid acceleration, in % / s.

[0059] When the acceleration rate of the power turbine is greater than or equal to the product of the maximum acceleration rate of the power turbine during normal engine operation and the margin coefficient, it indicates that the power turbine rotor's change trend is abnormal, that is:

[0060] V ≥ Y·V-max (2)

[0061] In the formula, V represents the acceleration rate of the power turbine, in % / s; V-max: the maximum acceleration rate of the power turbine under normal operating conditions such as engine start-up and rapid acceleration, in % / s; and Y represents the margin coefficient, with a value of 1.1 to 1.3.

[0062] In analyzing the trend of engine control stick angle change to determine the energy supply trend, the trend of engine control stick angle change includes: acceleration propulsion trend and deceleration pull-back trend;

[0063] The accelerating trend indicates that the energy supply trend is a gradual increase in fuel supply.

[0064] The deceleration and subsequent pullback trend indicates that the energy supply trend is a gradual decrease in fuel supply.

[0065] Based on the above, and according to the acceleration rate of the power turbine and the trend of energy supply, the protection method can be further divided into four cases.

[0066] In the first scenario, when the power turbine rotor changes normally and the energy supply trend is a gradual decrease in fuel supply, the engine is in a deceleration state. To prevent the power turbine speed from continuing to rise and triggering the over-speed protection logic, the fault condition is set as follows: the power turbine speed is greater than or equal to the power turbine speed protection value after an increase of 5%, that is, when NP≥NP-max+5%, the engine shutdown protection measure is taken. Here, NP represents the power turbine speed, and NP-max is the power turbine speed protection value, which is 115%.

[0067] In the second scenario, when the trend of the power turbine rotor change is normal and the energy supply trend is a gradual increase in fuel supply, the engine is in an acceleration state. The fault condition is set as follows: the power turbine speed is greater than or equal to the power turbine speed protection value after an increase of 5%, that is, when NP≥NP-max+5%, the engine shutdown protection measure is taken. Here, NP represents the power turbine speed, and NP-max is the power turbine speed protection value, which is 115%.

[0068] Simultaneously, the gas generator speed NG, turbine inlet temperature T45, and turbine torque MKP are acquired. When at least one of these parameters reaches its preset limit, it indicates that the engine has reached its maximum operating state. Given the gradually increasing fuel supply trend, it indicates that the engine's operating state can be further improved to cope with potential emergencies. To provide continuous power output to the helicopter while avoiding over-revving shutdown due to further increases in turbine speed, the turbine speed protection limit is increased by 1%, the turbine inlet temperature limit T45-max is increased by 15°C, and the turbine torque limit MKP-max is increased by 5%, to meet the demand for higher engine operating conditions.

[0069] In the third scenario, when the trend of the power turbine rotor change is abnormal and the energy supply trend is a gradual decrease in fuel supply, the engine is in a deceleration state. The fault condition is set as follows: the power turbine speed is greater than or equal to the power turbine speed protection value, that is, when NP≥NP-max, the engine shutdown protection measure is taken. Here, NP represents the power turbine speed, and NP-max is the power turbine speed protection value, which is 115%.

[0070] Meanwhile, in order to prevent the power turbine speed from running out of control and damaging the engine, the power turbine speed was reduced as soon as possible by reducing the gas generator speed limit NG-max by 5%, the power turbine inlet temperature limit T45-max by 30°C, and the power turbine torque limit Mkp-max by 20%.

[0071] In the fourth scenario, when the trend of the power turbine rotor change is abnormal and the energy supply trend is a gradual increase in fuel supply, the engine is in an acceleration state. Immediately issue a "power turbine fault" alarm signal and reduce the engine status to cruise state. At the same time, the fault condition is set as follows: the power turbine speed is greater than or equal to the power turbine speed protection value, that is, when NP≥NP-max, the engine shutdown protection measure is taken. Here, NP represents the power turbine speed, and NP-max is the power turbine speed protection value, which is 115%. If the engine status does not decrease in the early stage, the shutdown operation will be carried out when the fault condition is met.

[0072] refer to Figure 2 The present invention also provides a single-engine unmanned helicopter engine power turbine overspeed protection system, comprising:

[0073] The first analysis unit is used to analyze the acceleration rate of the power turbine to determine the trend of the power turbine rotor change.

[0074] The second analysis unit is used to analyze the trend of engine control stick angle change to determine the energy supply trend.

[0075] The judgment unit is used to determine the engine status based on the changing trend of the power turbine rotor and the energy supply trend.

[0076] The determination unit is used to determine fault conditions based on the engine status.

[0077] A detection unit is used to detect whether the fault condition has reached a threshold.

[0078] The measures unit is used to take protective measures when the fault condition reaches a threshold.

[0079] Among them, in analyzing the acceleration rate of the power turbine to determine the trend of the power turbine rotor, when the acceleration rate of the power turbine is less than or equal to the maximum acceleration rate of the power turbine when the engine is operating normally, it indicates that the trend of the power turbine rotor is normal.

[0080] When the acceleration rate of the power turbine is greater than or equal to the product of the maximum acceleration rate of the power turbine during normal engine operation and the margin coefficient, it indicates that the trend of the power turbine rotor change is abnormal.

[0081] In determining the energy supply trend by analyzing the change trend of the engine control stick angle, the change trend of the engine control stick angle includes: acceleration trend and deceleration pull-back trend. The acceleration trend indicates that the energy supply trend is a state of gradual increase in fuel supply.

[0082] The deceleration and pull-up trend indicates that the energy supply trend is a state of gradual reduction in fuel supply.

[0083] Among them, when determining the fault condition based on the engine status, when the trend of the power turbine rotor change is normal and the energy supply trend is a state of gradually increasing fuel supply or a state of gradually decreasing fuel supply, the fault condition is: the power turbine speed is greater than or equal to the power turbine speed protection value after an increase of 5%.

[0084] When the trend of the power turbine rotor is abnormal, and the energy supply trend is a gradual increase or decrease in fuel supply, the fault condition is: the power turbine speed is greater than or equal to the power turbine speed protection value.

[0085] In practical use, this invention allows for a short-term release of the power turbine overspeed protection speed, based on the turbine rotor's ability to operate at the overspeed protection speed for 5 minutes and at the burst speed for 30 seconds. Unlike the fixed-speed overspeed protection logic of the original technology, this invention flexibly adjusts the fault conditions and changes the specific value of the power turbine speed protection value based on the trends of engine control stick angle changes and power turbine acceleration rate changes. Different overspeed protection strategies are formulated for different working environments, giving the helicopter more power output and flight time in emergency situations, ensuring flight safety, and filling the gap in the lack of overspeed protection methods for single-engine unmanned helicopters.

[0086] Meanwhile, the overspeed protection strategy takes into account the overall adjustment of the gas generator speed limit, the power turbine inlet temperature limit, the power turbine torque limit, and the power turbine speed protection value. By adjusting upward and downward, it allows for short-term changes to the above limit values, so as to achieve the purpose of adjusting the engine status more quickly. It further provides contingency plans for emergency situations in flight and adapts to actual flight conditions.

[0087] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for overspeed protection of the power turbine of a single-engine unmanned helicopter, characterized in that, Includes the following steps: The acceleration rate of the power turbine is analyzed to determine the trend of the power turbine rotor. When the acceleration rate of the power turbine is less than or equal to the maximum acceleration rate of the power turbine when the engine is running normally, it indicates that the trend of the power turbine rotor is normal. When the acceleration rate of the power turbine is greater than or equal to the product of the maximum acceleration rate of the power turbine during normal engine operation and the margin coefficient, it indicates that the change trend of the power turbine rotor is abnormal. The energy supply trend is determined by analyzing the change trend of the engine control stick angle. The change trend of the engine control stick angle includes: acceleration trend and deceleration pull-back trend. The acceleration trend indicates that the energy supply trend is a state of gradually increasing fuel supply. The deceleration pull-back trend indicates that the energy supply trend is a state of gradually decreasing fuel supply. The fault condition is determined based on the engine status. The engine status is judged based on the trend of power turbine rotor change and energy supply trend. When the trend of power turbine rotor change is normal and the energy supply trend is a gradual increase or a gradual decrease in fuel supply, the fault condition is: the power turbine speed is greater than or equal to the power turbine speed protection value after an increase of 5%. When the trend of power turbine rotor change is abnormal and the energy supply trend is a gradual increase or a gradual decrease in fuel supply, the fault condition is: the power turbine speed is greater than or equal to the power turbine speed protection value. Detect whether the fault condition has reached a threshold; When the fault condition reaches the threshold, protective measures are taken.

2. The method for protecting the overspeed of a single-engine unmanned helicopter power turbine according to claim 1, characterized in that, in, When the trend of the power turbine rotor is normal and the energy supply trend is that the fuel supply is gradually increasing, the gas generator speed limit, the power turbine inlet temperature limit, and the power turbine torque limit should be increased. When the trend of the power turbine rotor is abnormal and the energy supply trend is a gradual decrease in fuel supply, the limits for gas generator speed, power turbine inlet temperature, and power turbine torque should be lowered.

3. The method for protecting the overspeed of a single-engine unmanned helicopter's power turbine according to claim 1, characterized in that, The protection measures include engine shutdown and control channel switching.

4. A single-engine unmanned helicopter engine power turbine overspeed protection system, characterized in that, include: The first analysis unit is used to analyze the acceleration rate of the power turbine to determine the trend of the power turbine rotor. When the acceleration rate of the power turbine is less than or equal to the maximum acceleration rate of the power turbine when the engine is working normally, it indicates that the trend of the power turbine rotor is normal. When the acceleration rate of the power turbine is greater than or equal to the product of the maximum acceleration rate of the power turbine during normal engine operation and the margin coefficient, it indicates that the change trend of the power turbine rotor is abnormal. The second analysis unit is used to analyze the change trend of the engine control stick angle to determine the energy supply trend. The change trend of the engine control stick angle includes: acceleration trend and deceleration pull-back trend. The acceleration trend indicates that the energy supply trend is a state of gradually increasing fuel supply. The deceleration pull-back trend indicates that the energy supply trend is a state of gradually decreasing fuel supply. The judgment unit is used to determine the engine status based on the changing trend of the power turbine rotor and the energy supply trend. The determination unit is used to determine the fault conditions based on the engine status. When the trend of the power turbine rotor is normal and the energy supply trend is a gradual increase or a gradual decrease in fuel supply, the fault condition is: the power turbine speed is greater than or equal to the power turbine speed protection value after an increase of 5%. When the trend of the power turbine rotor is abnormal and the energy supply trend is a gradual increase or a gradual decrease in fuel supply, the fault condition is: the power turbine speed is greater than or equal to the power turbine speed protection value. A detection unit is used to detect whether the fault condition has reached a threshold. The measures unit is used to take protective measures when the fault condition reaches a threshold.

Images