CN110901897A - Early warning separation control method for vortex ring state of unmanned helicopter - Google Patents
Early warning separation control method for vortex ring state of unmanned helicopter Download PDFInfo
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C17/00—Aircraft stabilisation not otherwise provided for
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- B—PERFORMING OPERATIONS; TRANSPORTING
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- B64U—UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
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Abstract
The invention discloses an early warning and separation control method for a vortex ring state of an unmanned helicopter, which really realizes vortex ring early warning and advanced protection functions, provides a solution for quickly and reasonably separating the vortex ring state even if the vortex ring state is entered, and ensures the flight safety of the unmanned helicopter. The early warning separation control method for the vortex ring state of the unmanned helicopter provided by the invention can judge the safety state of the current unmanned helicopter in real time, send the state information to the control end and prompt an operator to perform early warning, and meanwhile, the method is stable and reliable and has high early warning precision, so that the flight safety of the unmanned helicopter is greatly improved.
Description
Technical Field
The invention relates to the field of flight safety of unmanned helicopters, in particular to a method for controlling early warning and separation of a vortex ring state of an unmanned helicopter.
Background
With the rapid development of the unmanned helicopter industry, the flight safety of the unmanned helicopter is particularly important. For a variety of reasons, unmanned helicopters may cause a variety of abnormal flight conditions, including vortex ring conditions. The vortex ring state is an inherent dangerous state endangering flight safety during descent or gliding flight phases of a helicopter.
It has been found that when a helicopter is hovering or flying forward at a low speed, the rotor induces a speed due to the rotor's action in which the airflow upstream of the rotor disk is drawn in and then expelled downward, resulting in a lift force being generated by the rotor. The distribution of the induced speed of the rotor wing along the radius is approximatelyThe induced speeds are small, namely, the induced speeds are 0 at the center of the oar and the tip of the oar, and the lift force is 0. When the helicopter descends vertically, the airflow moves upwards according to the principle of relative motion, and the downward rotor wing induces the speed to meet the upward airflow to form turbulent vortex. When the helicopter descends slowly, the induced airflow at the paddle disc still plays a dominant role, but the wake flow is disturbed a little, and when the descending speed V of the helicopter is reducedyRotor average induced velocity upsilon more than 0.28 times10In the meantime, the upward air flow rushes through the rotor disk near the center and tip of the rotor, and is then sucked by the rotor, causing the rotor to operate in a toroidal rotating air mass with unstable flow regime, referred to as the typical vortex ring regime, in which the speed V is reduced while the rotor is moving downyAnd mean induced velocity v of rotor10The following relations are formed between the two components:
most severe at times. At the moment, the lift force changes unsteady, the rotor wing consumes a large amount of power, and the pitching moment and the rolling moment are also changed, so that the helicopter jolts, falls and fails to operate. Thus, it is a high risk of a helicopter flying in a vortex ring state, which could cause a crash if there is not enough altitude or if corrective and timely measures are not taken.
Therefore, how to perform early warning on the vortex ring state of the unmanned helicopter is an urgent problem to be solved by the technical personnel in the field.
Disclosure of Invention
The invention aims to provide a method for controlling early warning of the vortex ring state of an unmanned helicopter, which is used for controlling and avoiding the unmanned helicopter from entering the vortex ring state in flight by calculating the vortex ring state boundary and implementing control to be separated from the vortex ring state once the unmanned helicopter enters the vortex ring state.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
the invention provides an early warning separation control method for a vortex ring state of an unmanned helicopter, which comprises the following operation steps:
the forward flight airspeed V of the unmanned helicopter is given through calculationXAnd a falling speed VyA fixed flight relationship curve therebetween;
calculating a critical downward sliding angle A of an alarm boundary of the current unmanned helicopter according to the fixed flight relation curve, and calculating a critical angle B of a danger boundary of the current unmanned helicopter according to the fixed flight relation curve;
and in the real-time flight process, calculating in real time to obtain a current downward sliding angle C, judging the flight state of the current unmanned helicopter according to the relation between the current downward sliding angle C and the critical downward sliding angle A of the warning boundary and the critical angle B of the danger boundary, and performing vortex ring boundary early warning operation.
Preferably, as one possible embodiment; in the real-time flight process, calculating in real time to obtain a current downward sliding angle C, judging the flight state of the current unmanned helicopter according to the relation between the current downward sliding angle C and the critical downward sliding angle A of the warning boundary and the critical angle B of the danger boundary, and performing vortex ring boundary early warning operation, wherein the method specifically comprises the following operation steps:
in the real-time flight process, the actual forward flight airspeed V of the current unmanned helicopter is obtained through real-time calculationXObtaining the descending speed V of the current unmanned helicopter in real timeyFrom real-time measured descent speed VyFront flying airspeed VXCalculating to obtain a current downward sliding angle C;
wherein, tan c is a dropping speed VyFront flying airspeed VX；
Judging whether the current downward sliding angle C is smaller than a critical downward sliding angle A of an alarm boundary or not, and judging whether the current unmanned helicopter is in a normal flight state or not;
judging whether the actual downward sliding angle C is equal to the critical downward sliding angle A of the warning boundary or not, and judging whether the current unmanned helicopter is in the warning boundary state or not;
judging whether the real downward sliding angle C is larger than a critical downward sliding angle A of the warning boundary and smaller than a critical angle B of the danger boundary, and judging that the current unmanned helicopter is in a serious warning state;
and judging that the current unmanned helicopter is in a vortex ring danger warning state if the real downward sliding angle C is larger than or equal to the critical angle B of the danger boundary.
Preferably, as one possible embodiment; after the unmanned helicopter executes vortex ring boundary early warning operation, the method further comprises the following operation steps:
displaying and reporting the actual forward flight airspeed V to a control end of an operator at any time after the current unmanned helicopter is judged to be in the alarm boundary stateXAnd a falling speed VyAnd the warning lamp is controlled to realize the yellow lamp lighting warning operation, and the operator is prompted to enter the warning boundary state;
displaying and reporting the actual forward flight airspeed V to a control end of an operator at any moment after judging that the current unmanned helicopter is in the serious warning stateXAnd a falling speed VyAnd the warning lamp is controlled to realize yellow lamp flashing warning operation to prompt the operator to enter a serious warning state;
displaying and reporting the actual forward flight airspeed V to a control end of an operator at any time after judging that the current unmanned helicopter is in the vortex ring danger warning stateXAnd a falling speed VyAnd the warning lamp is controlled to realize the red lamp lighting warning operation, and the operator is prompted to enter the vortex ring danger warning state.
Preferably, as one possible embodiment; when the current unmanned helicopter is judged to be in any one of a warning boundary state, a serious warning state or a vortex ring danger warning state, the method further comprises the step of controlling the unmanned helicopter to realize release control operation, wherein the release control operation comprises the following operations:
acquiring the current height of the unmanned helicopter, and judging whether the current height is higher than or equal to a standard height threshold value;
if so, controlling the unmanned helicopter to increase forward flight airspeed so as to get rid of the vortex ring state;
and if the judgment result is negative, controlling the unmanned helicopter to reduce the total distance, so that the energy consumption of the rotor wing is reduced, and the ground contact speed is reduced.
Preferably, as one possible embodiment; and in the flight control program, if the real downward sliding angle C > the critical downward sliding angle A of the alarm boundary, controlling to automatically increase the speed.
By adopting the technical scheme, the early warning separation control method for the vortex ring state of the unmanned helicopter, provided by the application, has the following technical effects: the early warning separation control method for the vortex ring state of the unmanned helicopter can actually realize two functions of vortex ring early warning and vortex ring separation; for example, when vortex ring early warning is carried out, the vortex ring early warning actually refers to a fixed flight relation curve of the current unmanned helicopter, and the relation curve shows that the forward flight airspeed V of the unmanned helicopter in a windspeed-free state is analyzedXAnd a falling speed VyThe relationship between; two important reference angles, namely a critical downward sliding angle A of the alarm boundary of the current unmanned helicopter, are obtained according to the relation curve, and a critical angle B of the danger boundary of the current unmanned helicopter is calculated according to the fixed flight relation curve; it is clear that the fixed flight relationship curves are actually two boundary curves, one being the alarm boundary and one being the vortex ring boundary. For a specific unmanned helicopter, the two boundary curves can be calculated, and unmanned helicopters of different types have specific relation curves.
However, in general, during flight, the unmanned helicopter is influenced by wind speed, and at this time, the current forward flight airspeed V is required to be usedXAnd a falling speed VyCalculating to obtain a current downward sliding angle C; and then, judging the flight state of the current unmanned helicopter by comparing the relation between the current downward sliding angle C and the critical downward sliding angle A of the warning boundary and the critical angle B of the danger boundary, and performing vortex ring boundary early warning operation.
Generally, if the current downward sliding angle C is smaller than the critical downward sliding angle A of the warning boundary, the current unmanned helicopter is judged to be in a normal flight state; if the real downward sliding angle C is equal to the critical downward sliding angle A of the warning boundary, judging that the current unmanned helicopter is in the warning boundary state; if the real downward sliding angle C is larger than the critical downward sliding angle A of the warning boundary and smaller than the critical angle B of the danger boundary, judging that the current unmanned helicopter is in a serious warning state; and if the real downward sliding angle C is larger than or equal to the critical angle B of the danger boundary, judging that the current unmanned helicopter is in a vortex ring danger warning state.
When the current unmanned helicopter breaks away from the vortex ring state, the current flight height needs to be considered, and the vortex ring state is broken away by cooperating with the forward flight airspeed and the collective pitch control; obviously, the early warning separation control method for the vortex ring state of the unmanned helicopter really realizes the vortex ring early warning and early protection functions, provides a solution for quickly and reasonably separating the vortex ring state even if the vortex ring state is entered, and ensures the flight safety of the unmanned helicopter.
The early warning separation control method for the vortex ring state of the unmanned helicopter provided by the invention can judge the safety state of the current unmanned helicopter in real time, send the state information to the control end and prompt an operator to perform early warning, and meanwhile, the method is stable and reliable and has high early warning precision, so that the flight safety of the unmanned helicopter is greatly improved.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments or the technical solutions in the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a graph of a fixed flight relationship indicated in a method for early warning of the vortex ring state of an unmanned helicopter in an embodiment of the present invention;
FIG. 2 is a diagram showing a relationship change between required power and forward flight airspeed indicated in the method for controlling early warning of the vortex ring state of an unmanned helicopter in an embodiment of the present invention;
FIG. 3 is a diagram showing a relationship change between a collective pitch and a forward flight airspeed indicated in the method for controlling early warning of the vortex ring state of the unmanned helicopter in the embodiment of the present invention;
fig. 4 is an operation flowchart of an early warning disengagement control method for a vortex ring state of an unmanned helicopter according to an embodiment of the present invention.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that "connected" is to be understood broadly, for example, it may be fixed, detachable, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The present invention will be described in further detail below with reference to specific embodiments and with reference to the attached drawings.
The invention provides an early warning separation control method for a vortex ring state of an unmanned helicopter, which comprises the following operation steps (the specific method steps are shown in figure 4):
step S100: the forward flight airspeed V of the unmanned helicopter is given through calculationXAnd a falling speed VyA fixed flight relationship curve therebetween;
step S200: calculating a critical downward sliding angle A of an alarm boundary of the current unmanned helicopter according to the fixed flight relation curve, and calculating a critical angle B of a danger boundary of the current unmanned helicopter according to the fixed flight relation curve;
step S300: and in the real-time flight process, calculating in real time to obtain a current downward sliding angle C, judging the flight state of the current unmanned helicopter according to the relation between the current downward sliding angle C and the critical downward sliding angle A of the warning boundary and the critical angle B of the danger boundary, and performing vortex ring boundary early warning operation.
It should be noted that, in the specific technical solution of the embodiment of the present invention, when vortex ring early warning is performed, reference is actually made to the current unmanned helicopterThe fixed flight relation curve of the helicopter shows and analyzes the forward flight airspeed V of the unmanned helicopterXAnd a falling speed VyThe relationship between (see in particular fig. 1); two important reference angles, namely a critical downward sliding angle A of the alarm boundary of the current unmanned helicopter, are obtained according to the relation curve, and a critical angle B of the danger boundary of the current unmanned helicopter is calculated according to the fixed flight relation curve; it is clear that the fixed flight relationship curves are actually two boundary curves, one being the alarm boundary and one being the vortex ring boundary. For a specific unmanned helicopter, the two boundary curves can be calculated, and unmanned helicopters of different types have specific relation curves. The early warning separation control method for the vortex ring state of the unmanned helicopter provided by the embodiment of the invention is vortex ring state early warning prevention and separation control realized by utilizing the relation curve.
Preferably, as one possible embodiment; in step S300, the following steps are specifically included:
step S310: in the real-time flight process, the actual forward flight airspeed V of the current unmanned helicopter is obtained through real-time calculationXObtaining the descending speed V of the current unmanned helicopter in real timeyFrom real-time measured descent speed VyFront flying airspeed VXCalculating to obtain a current downward sliding angle C;
wherein, tan c is a dropping speed VyFront flying airspeed VX；
Step S320: judging whether the current downward sliding angle C is smaller than a critical downward sliding angle A of an alarm boundary or not, and judging whether the current unmanned helicopter is in a normal flight state or not;
judging whether the actual downward sliding angle C is equal to the critical downward sliding angle A of the warning boundary or not, and judging whether the current unmanned helicopter is in the warning boundary state or not;
judging whether the real downward sliding angle C is larger than a critical downward sliding angle A of the warning boundary and smaller than a critical angle B of the danger boundary, and judging that the current unmanned helicopter is in a serious warning state;
and judging that the current unmanned helicopter is in a vortex ring danger warning state if the real downward sliding angle C is larger than or equal to the critical angle B of the danger boundary.
It should be noted that, in the specific technical solution of the embodiment of the present invention, during flight, the unmanned helicopter is affected by the wind speed, and at this time, the current forward flight airspeed V needs to be usedXAnd a falling speed VyCalculating to obtain a current downward sliding angle C; and then, judging the flight state of the current unmanned helicopter by comparing the relation between the current downward sliding angle C and the critical downward sliding angle A of the warning boundary and the critical angle B of the danger boundary, and performing vortex ring boundary early warning operation. Generally, if the current downward sliding angle C is smaller than the critical downward sliding angle A of the warning boundary, the current unmanned helicopter is judged to be in a normal flight state; if the real downward sliding angle C is equal to the critical downward sliding angle A of the warning boundary, judging that the current unmanned helicopter is in the warning boundary state; if the real downward sliding angle C is larger than the critical downward sliding angle A of the warning boundary and smaller than the critical angle B of the danger boundary, judging that the current unmanned helicopter is in a serious warning state; and if the real downward sliding angle C is larger than or equal to the critical angle B of the danger boundary, judging that the current unmanned helicopter is in a vortex ring danger warning state.
The following description will be given taking an R44 helicopter as an example. Let the unmanned helicopter fly at the ground speed of 30km/h (point 0 in fig. 2), for example, when encountering 10km/h of wind, for example, flying in the wind, and the airspeed of 40km/h (point 2 in fig. 2), for example, flying downwind, and the airspeed of 20km/h (point 1 in fig. 2).
From fig. 2 and 3, it can be seen that:
it can be seen that in low speed flight, the power demand and collective pitch are sensitive to changes in airspeed. However, when the airspeed is less than 50km/h, the airspeed meter is inaccurate in indication, the speed indicator can only display the ground speed, the aircraft movement seen by the operator is also the ground speed, at this time, the aircraft flies downwind (the wind speed is set to be 10km/h), the aircraft flies fast, the operator mistakenly thinks that the aircraft is at the 2-point position in fig. 2, the distance of descent is reduced, and actually, the airspeed is very small (at the 1-point position), and the distance of the aircraft should be increased. Due to reverse operation, the aircraft falls high and easily enters the vortex ring shapeState. If the airplane flies in front of or away from the operating hand, the operating hand cannot judge the flying speed, and the operating fault is easily caused to enter the vortex ring state. Most of unmanned helicopters are ultra-light helicopters, the load of a paddle disk is small, the induction speed is low, and the helicopter is driven to rotate at a speed according to the descent rate VY≥0.28υ10(υ10Average induced speed of the rotor) enters the vortex ring state, and the unmanned helicopter enters the vortex ring state with a small descent rate. In addition, the unmanned helicopter starts to test flight, starts from a model airplane control mode, and must fly in a visual range due to manual control, and the unmanned helicopter is easy to enter a vortex ring state because the unmanned helicopter is determined to fly not far, not high and not fast. If there is more wind, the situation is more unfavorable; the current flight state of the unmanned helicopter is judged by specifically comparing the relation between the current downward sliding angle C and the critical downward sliding angle A of the warning boundary and the critical angle B of the danger boundary, so that the method is an effective prevention method.
Preferably, as one possible embodiment; after step S300 (i.e. the unmanned helicopter performs vortex ring boundary early warning operation), the following operation step S400 is further included:
step S410: displaying and reporting the actual forward flight airspeed V to a control end of an operator at any time after the current unmanned helicopter is judged to be in the alarm boundary stateXAnd a falling speed VyAnd the warning lamp is controlled to realize the yellow lamp lighting warning operation, and the operator is prompted to enter the warning boundary state;
preferably, as one possible embodiment; and in the flight control program, if the real downward sliding angle C > the critical downward sliding angle A of the alarm boundary, controlling to automatically increase the speed.
Step S420: displaying and reporting the actual forward flight airspeed V to a control end of an operator at any moment after judging that the current unmanned helicopter is in the serious warning stateXAnd a falling speed VyAnd the warning lamp is controlled to realize yellow lamp flashing warning operation to prompt the operator to enter a serious warning state;
step S430: after the current unmanned helicopter is judged to be in the vortex ring danger warning state, the current unmanned helicopter is displayed to the control end of the manipulator at any momentIndicating the actual forward flight airspeed VXAnd a falling speed VyAnd the warning lamp is controlled to realize the red lamp lighting warning operation, and the operator is prompted to enter the vortex ring danger warning state.
It should be noted that, in the specific technical solution of the embodiment of the present invention, the different flight states can be displayed through different warning states; except for the normal flight state, the unmanned helicopter generally has the following dangerous flight states; namely an alarm boundary state (at the moment, the real glide angle C is equal to the critical glide angle A of the alarm boundary, a severe alarm state (at the moment, the real glide angle C is larger than the critical glide angle A of the alarm boundary and smaller than the critical angle B of the danger boundary) and a vortex ring danger state (at the moment, the real glide angle C is larger than or equal to the critical angle B of the danger boundary), after the three states appear, the operator at the control end can be prompted by the bright lamp operation of different colors, and simultaneously, the actual forward flying airspeed V can be usedXAnd a falling speed VyThe real-time transmission is carried out to the control end, and the real-time display and report are carried out through the display screen of the control end, so that the flight state of the current unmanned helicopter can be conveniently known by an operator in real time, and misjudgment and misoperation are avoided.
Preferably, as one possible embodiment; after step S420, controlling the unmanned helicopter to implement a release control operation, including the following operations:
step S510: acquiring the current height of the unmanned helicopter, and judging whether the current height is higher than or equal to a standard height threshold value;
if so, controlling the unmanned helicopter to increase forward flight airspeed so as to get rid of the vortex ring state;
it should be noted that, if the unmanned helicopter enters the vortex ring state once, the forward flight airspeed can be increased to escape from the vortex ring state when the flying altitude is allowed (i.e. whether the current altitude is within the allowed range is judged, and if the current altitude is within the standard altitude threshold, the forward flight airspeed can be increased to escape from the vortex ring state); because of the altitude that must be lost when the forward airspeed increases, as shown in fig. 2, the forward airspeed increases requiring a reduction in power, thus reducing the descent speed, and then, looking again at fig. 1, as shown in fig. 1, the unmanned helicopter can now be taken out of the vortex ring state.
And if the judgment result is negative, controlling the unmanned helicopter to reduce the total distance, so that the energy consumption of the rotor wing is reduced, and the ground contact speed is reduced. It should be noted that, if the height is not allowed, that is, the current height is smaller than the standard height threshold, the total distance can be controlled to be reduced, so that the energy of the rotor wing is reduced, the ground contact speed is reduced, and the unmanned helicopter can be ensured to safely land.
According to investigation, in the flight process of a certain unmanned helicopter, 4 times of 8 major accidents enter a vortex ring state, so that the airplane is seriously damaged. However, the 4 times of entering the vortex ring state are different from each other in each case and are related to wind speed, wind direction and control errors, and the flight measurement results provide valuable information for researching how the unmanned helicopter avoids and changes the vortex ring state. However, the early warning separation control method for the vortex ring state of the unmanned helicopter provided by the invention provides powerful technical support for safe flight of the unmanned helicopter.
In summary, the early warning and separation control method for the vortex ring state of the unmanned helicopter really realizes the vortex ring early warning and the advanced protection function, provides a solution for quickly and reasonably separating the vortex ring state even if the vortex ring state is entered, and ensures the flight safety of the unmanned helicopter. The early warning separation control method for the vortex ring state of the unmanned helicopter provided by the invention can judge the safety state of the current unmanned helicopter in real time, send the state information to the control end and prompt an operator to perform early warning, and meanwhile, the method is stable and reliable and has high early warning precision, so that the flight safety of the unmanned helicopter is greatly improved. In addition, the embodiment of the invention not only provides a method for preventing the unmanned helicopter from entering the vortex ring state, but also provides a solution for getting rid of; if the aircraft once enters the vortex ring state, the vortex ring state is removed by increasing the speed when the altitude permits because the altitude is lost when the speed is increased. If the height is not allowed, the total distance should be reduced, the energy consumed by the rotor is reduced, and the ground contact speed can be reduced.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (5)
1. A pre-warning separation control method for the vortex ring state of an unmanned helicopter is characterized by comprising the following operation steps:
the forward flight airspeed V of the unmanned helicopter is given through calculationXAnd a falling speed VyA fixed flight relationship curve therebetween;
calculating a critical downward sliding angle A of an alarm boundary of the current unmanned helicopter according to the fixed flight relation curve, and calculating a critical angle B of a danger boundary of the current unmanned helicopter according to the fixed flight relation curve;
and in the real-time flight process, calculating in real time to obtain a current downward sliding angle C, judging the flight state of the current unmanned helicopter according to the relation between the current downward sliding angle C and the critical downward sliding angle A of the warning boundary and the critical angle B of the danger boundary, and performing vortex ring boundary early warning operation.
2. The method for early warning of the vortex ring state of the unmanned helicopter according to claim 1, wherein the current glide angle C is obtained by real-time calculation during the real-time flight, the flight state of the current unmanned helicopter is determined according to the relationship between the current glide angle C and the critical glide angle a of the warning boundary and the critical angle B of the danger boundary, and the vortex ring boundary early warning operation is performed, specifically comprising the following steps:
in the real-time flight process, the actual forward flight airspeed V of the current unmanned helicopter is obtained through real-time calculationXObtaining the descending speed V of the current unmanned helicopter in real timeyFrom real-time measured descent speed VyFront flying airspeed VXCalculating to obtain a current downward sliding angle C;
wherein, tan c is a dropping speed VyFront flying airspeed VX；
Judging whether the current downward sliding angle C is smaller than a critical downward sliding angle A of an alarm boundary or not, and judging whether the current unmanned helicopter is in a normal flight state or not;
judging whether the actual downward sliding angle C is equal to the critical downward sliding angle A of the warning boundary or not, and judging whether the current unmanned helicopter is in the warning boundary state or not;
judging whether the real downward sliding angle C is larger than a critical downward sliding angle A of the warning boundary and smaller than a critical angle B of the danger boundary, and judging that the current unmanned helicopter is in a serious warning state;
and judging that the current unmanned helicopter is in a vortex ring danger warning state if the real downward sliding angle C is larger than or equal to the critical angle B of the danger boundary.
3. The early warning disengagement control method for the vortex ring state of the unmanned helicopter according to claim 2, characterized in that after the unmanned helicopter performs the vortex ring boundary early warning operation, the method further comprises the following operation steps:
displaying and reporting the actual forward flight airspeed V to a control end of an operator at any time after the current unmanned helicopter is judged to be in the alarm boundary stateXAnd a falling speed VyAnd the warning lamp is controlled to realize the yellow lamp lighting warning operation, and the operator is prompted to enter the warning boundary state;
displaying and reporting the actual forward flight airspeed V to a control end of an operator at any moment after judging that the current unmanned helicopter is in the serious warning stateXAnd a falling speed VyAnd the warning lamp is controlled to realize yellow lamp flashing warning operation to prompt the operator to enter a serious warning state;
displaying and reporting the actual forward flight airspeed V to a control end of an operator at any time after judging that the current unmanned helicopter is in the vortex ring danger warning stateXAnd a falling speed VyAnd controls the warning lamp to realize the red lamp lighting warning operation and the prompt operationThe practitioner enters the vortex ring hazard warning state.
4. The early warning disengagement control method for the vortex ring state of the unmanned helicopter according to claim 3, wherein when the current unmanned helicopter is determined to be in any one of the warning boundary state, the severe warning state or the vortex ring danger warning state, the method further comprises the step of controlling the unmanned helicopter to realize disengagement control operation, which comprises the following operations:
acquiring the current height of the unmanned helicopter, and judging whether the current height is higher than or equal to a standard height threshold value;
if so, controlling the unmanned helicopter to increase forward flight airspeed so as to get rid of the vortex ring state;
and if the judgment result is negative, controlling the unmanned helicopter to reduce the total distance, so that the energy consumption of the rotor wing is reduced, and the ground contact speed is reduced.
5. The unmanned helicopter vortex ring state early warning disengagement control method according to claim 3, wherein in the flight control program, if the true slip angle C > the critical slip angle A of the warning boundary, the control automatically increases the speed.
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Cited By (5)
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| CN113252284A (en) * | 2021-07-02 | 2021-08-13 | 中国空气动力研究与发展中心低速空气动力研究所 | Ground simulation method for helicopter rotor vortex ring state improvement test |
| CN114563154A (en) * | 2022-04-28 | 2022-05-31 | 中国空气动力研究与发展中心低速空气动力研究所 | Test method and system for determining helicopter vortex ring state boundary |
| CN114613197A (en) * | 2022-03-25 | 2022-06-10 | 中国人民解放军陆军航空兵学院 | Vortex ring state monitoring alarm handling prompt system in helicopter flight process |
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| CN114563154A (en) * | 2022-04-28 | 2022-05-31 | 中国空气动力研究与发展中心低速空气动力研究所 | Test method and system for determining helicopter vortex ring state boundary |
| RU2818823C1 (en) * | 2023-11-29 | 2024-05-06 | Акционерное общество "Национальный центр вертолетостроения им. М.Л. Миля и Н.И. Камова" (АО "НЦВ Миль и Камов") | Method of preventing rotorcraft from entering vortex ring state zone at pre-landing maneuvers in hovering mode |
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