RU2356099C1 - Method for prevention of threat of aircraft collision with obstacles of underlying surface - Google Patents

Abstract

FIELD: physics, measurement.

SUBSTANCE: invention is related to the field of aviation engineering, namely to on-board systems of prevention of collision with ground. Method consists in preliminary creation of data base of underlying surface relief, aeronavigation data base, data base of aircraft (AC) performance characteristics. Borders of attention zone and control zone (CZ) are calculated, obstacle of highest threat in CZ is separated, which is located in zone of calculated trajectory prediction. Taking into account data on limitations of AC motion parametres and external effects, parametres of nominal flight are calculated, which provide for obstacle overflight at height close to minimum permissible height. Control signals are generated according to selected control law and with account of environment factors effect, which are sent to actuators of flight control and engine thrusts, and are also displayed on screen of flight director.

EFFECT: expansion of resources of existing systems for prevention of collision with ground obstacles and reduction of collision risk under effect of wind disturbances and under effect of human factor.

5 cl, 7 dwg, 2 app

Description

The invention relates to the field of aviation technology, namely to airborne collision avoidance systems.

It is known that the causes of severe accidents and accidents with operational aircraft (LA) are a combination of a number of unfavorable factors, namely the absence or incompleteness of information about ground obstacles, the influence of environmental factors and crew errors.

A known system for preventing collisions of aircraft with land according to the patent of the Russian Federation No. 2271039 C1, IPC 7 G08G 5/04, B64D 45/04, publ. 02.27.06 g. (Www.fips.ru).

The known method consists in the fact that the system contains a terrain database, an adaptation module for the type of aircraft, filling and updating blocks, a block of information sensors and a control post. The vertical flyby unit is connected to the warning and display units. In addition, a local side maneuver card, a local card limiter, and a heading direction block have been introduced into the system. The system allows you to determine the direction of a side turn in case of danger of an aircraft collision with the ground while maintaining the flight direction.

The disadvantage of this invention is that the system performs the functions of detecting a collision threat, signaling the crew about the threat and makes recommendations on the direction of the maneuver, but does not generate control signals designed to perform the evasion maneuver in automatic mode.

There is also a method of reducing the risk of collision of an aircraft (aircraft) with the earth's surface (“Display for terrain avoidance”) according to the application No. WO 2004084152, IPC G08G 05/04 of 09/30/2004 (http://v3.espacenet.com).

The method consists in preliminarily forming a database of the relief of the underlying surface (BDIS), an aeronautical database (ANBD), and a database of flight performance characteristics (LTH) of the aircraft. During the flight, obstacles are highlighted at the heading of the flight, which pose a threat of aircraft collision with the identified obstacles. Then calculate one or more flight paths of the aircraft, excluding its collision with an extreme of the number of selected obstacles. Based on the calculated trajectory, the parameters of evading the aircraft from the obstacle are calculated, in accordance with the values of which they generate electrical control signals and display them on the display as recommendations for the aircraft crew to perform a maneuver.

The disadvantage of this analogue is that the generated signals have relatively low information content, there is no accounting for the influence of possible changes in the speed of wind flows, as well as the impossibility of direct and immediate implementation in modern and promising integrated on-board automated flight complexes of manned aircraft and in automatic control systems for unmanned aircraft.

Closest in technical essence to the claimed one is a known method for detecting and preventing the threat of an aircraft collision with obstacles of the underlying surface according to patent No. RU 2297047, IPC G08G 05/04 of 2005.08.03 (www.fips.ru).

The prototype method consists in the fact that pre-form BDFPP, ANBD, aircraft LTH database. The boundaries of the control zone (ZU) and the zone of attention (SV) at all stages of the flight of the aircraft are calculated. Correct the boundaries of the zones when maneuvering aircraft depending on the magnitude of the vertical speed and changes in wind speed. Allocate obstacles to the underlying surface that fall into the zones, and determine their excess over the boundaries of the zones. Form information and control signals to the aircraft crew with their subsequent indication. The procedure for processing, indicating signals for the crew, as well as an additional change in the zone boundaries when changing the stages and flight modes of the aircraft simplifies the decision by the crew to perform a maneuver that ensures timely evasion of aircraft from obstacles.

The prototype method has the same disadvantages as the above analogues. Namely, it does not allow automation of the evasion maneuver process, which reduces the level of flight safety and does not allow the use of this method in control systems for unmanned aerial vehicles. The second major drawback is that this method does not guarantee for a corrected aircraft to overcome obstacles with a minimum required margin in height for any changes in wind speed within acceptable limits.

The claimed technical solution expands the arsenal of tools for this purpose.

It is known that in rough terrain with difficult terrain, as well as near terrestrial obstacles, wind field distortions occur that have a significant effect on flight parameters, and their appearance is usually sudden. The human factor has a significant impact on the outcome of overcoming obstacles, namely, erroneous actions of the pilot and delay, incorrect assessment of the situation and inadequate reaction.

In order to reduce the risk of collision with ground-based obstacles when approaching an operational aircraft, complete and reliable information should be used on board the aircraft, automate the processing of this information taking into account the influence of external disturbing influences and the human factor, as well as the development and implementation of control actions aimed at evading from collision with the ground.

This goal is achieved by the fact that in the known method of preventing a collision threat of an aircraft equipped with actuators of flight altitude control, as well as actuators of engine thrust control, with obstructions of the underlying surface, which consists in preliminarily forming a database of the relief of the underlying surface, an aeronautical database , a database of the flight technical characteristics of the aircraft, during the flight, the boundaries of the attention areas sequentially adjacent to each other are calculated areas and control zones, and from the obstacles of the underlying surface, obstacles are identified that pose a threat of collision of the aircraft with them, namely, those falling into the control zone and the attention zone, and the flight paths and aircraft deviation parameters excluding the aircraft collision with obstacles are calculated with taking into account all the obstacles in the control zone, and each calculated trajectory, eliminating the threat of a collision of an aircraft with an obstacle, is the axis of the corresponding The current motion prediction region, the width of which depends on the speed and altitude of the aircraft, generates electrical control signals that are displayed by means of indicators to take them into account when the crew decides to maneuver the aircraft according to the invention for a calculated horizontal trajectory within the boundaries control zones highlight an extreme obstacle located in the forecast area of the calculated trajectory, taking into account restrictions on the parameters of motion and disturbance the trajectory in the vertical plane is extrapolated and the predicted flight height of the obstacle is calculated, the minimum permissible flight height of the specified extreme obstacle is calculated, as well as the nominal flight height, the parameters of the nominal flight path in the vertical plane are calculated, the boundary of the permissible deviations from the nominal path, the magnitude and control sign in height are calculated , depending on deviations from the nominal trajectory and motion parameters of the aircraft, electrical si control signals to the actuator of the flight altitude control, and when exceeding the lower limit of permissible deviations from the nominal trajectory, as well as when the aircraft’s flight speed decreases relative to the nominal one or when it is hit by wind shear conditions, a control signal is generated that transfers the engines to the maximum permissible traction with the issuance of an alarm to the crew, and if the predicted height of the flight of an extreme obstacle is less than the minimum allowable, vertical maneuver complements block and decide maneuver in a horizontal plane.

Also new is the fact that when flying an aircraft in conditions of weak wind disturbances or in their absence, the control signal for height is calculated as the sum of deviations from the nominal path in height, deviations from the nominal vertical speed and pitch speed, each of which is multiplied by constant or variable coefficients depending on the type of aircraft and flight mode. The specified amount or part thereof is limited in amplitude, an electrical signal is supplied to the actuator of the flight altitude control, and the border of permissible deviations from the nominal trajectory is a line coinciding with the trajectories of movement with available vertical overload.

When flying in difficult weather conditions, weather forecast data on the range of changes in wind speed and direction are entered in advance, the aerodynamic coefficients of the aircraft for the current stage and flight mode are calculated, as well as restrictions on the movement parameters, the characteristics of the nominal movement and the nominal trajectory are calculated, the flight along which guarantees the passage of the obstacle with excess corresponding to the minimum permissible height for any changes in wind disturbances in the previously specified restrictions. At each moment of time from the entrance to the control zone and to the flight of an extreme obstacle (EP), the controls that ensure stabilization on the nominal path are calculated, the corresponding electrical signals are generated, and they are fed to the actuator of the aircraft controls.

For an aircraft of a helicopter circuit, the control actions for height are fed to the drive of the integrated step-gas control, as well as to the drive of the swashplate.

The calculated control signal is smoothed, scaled and fed to the flight control device in the form of a director index, the pilot of the aircraft, in accordance with the position of the command index, controls the aircraft, acting on its controls, and thereby stabilizes the aircraft on a nominal path.

For an unmanned aerial vehicle, control signals are generated at a ground-based stationary or mobile flight control station and, using a data line, are transferred to an aircraft equipped with a transceiver, converted into electrical signals that are transmitted to the actuators of the flight altitude and engine thrust control.

Thanks to this new set of essential features, due to the formation of control signals affecting the actuators of the flight altitude and engine thrust control and signaling to the crew, the aircraft is able to maneuver the aircraft in automatic mode, taking into account the influence of wind disturbances, which reduces the influence of the human factor and the likelihood of a collision obstacles to the underlying surface. The analysis of the prior art made it possible to establish that analogues, characterized by a combination of features that are identical to all the features of the claimed technical solution, are absent in known media, which indicates the compliance of the claimed method with the condition of patentability "novelty".

The search results for known solutions in this and related fields of technology in order to identify features that match the distinctive features of the prototype features showed that they do not follow explicitly from the prior art. The prior art also did not reveal the popularity of the impact provided by the essential features of the claimed invention, the transformations on the achievement of the specified technical result. Therefore, the claimed invention meets the condition of patentability "inventive step".

The claimed method is illustrated by drawings, which show:

figure 1 explains the vertical and horizontal section of the control zone and the attention zone;

figure 2 explains the view of the trajectory in a vertical plane;

figure 3 is a structural diagram of an on-board device that implements the claimed method;

figure 4 - algorithm of the processor;

5 is a view of a display screen of a flight control indicator;

Fig.6 explains the construction of the nominal path and the area of permissible deviations;

Fig.7 explains the characteristics of the nominal movement under the action of extreme wind disturbances.

When flying aircraft of various types at low altitudes, especially along free trajectories, there may be a danger of encountering ground-based obstacles, including terrain elements or artificial structures. This danger increases under the influence of various kinds of interference created by weather conditions, and the human factor.

Known solutions to this problem are based on the inclusion of special collision avoidance systems in the on-board equipment that use information about the obstacles of the underlying surface, but they do not fully comply with safety requirements, as the signals they generate are not informative enough and do not take into account the dynamics of changes in flight modes , changes in weather conditions and other destabilizing factors.

An adequate solution can be found by constructing a forecast of the trajectory that provides for avoiding the threat of a collision taking into account the action of environmental factors, as well as automating the development of control actions to eliminate this threat and automating the process of managing the maneuver.

This problem is solved in the claimed method.

The possibility of implementing the inventive method with the achievement of the specified technical result is explained as follows.

At the stage of flight preparation, databases are preliminarily formed.

As BDRPP use digital maps of the terrain, which are previously stored in the memory of the on-board system at the stage of flight preparation, taking into account the planned flight route and possible deviations of the aircraft from this route (alternate aerodromes, bypass lightning activities, etc.). In digital form, the map contains data on the relief of the underlying surface and can be used for further calculations without preliminary processing of its data or according to the rules for using digital maps contained in such a database. Digital maps of all elevations (obstacles), both natural and artificial, store data on their geographical coordinates: φ, [deg] - latitude, λ, [deg] - longitude, y _e , [m] - height above the earth ellipsoid (geoid).

The ANBD includes information about airports and contains data on the coordinates of runways (runways), their lengths, the direct and reverse azimuths of the axis of the runway, as well as information on approach and takeoff patterns. These data are taken into account to determine the stage and flight mode of the aircraft (cruise flight, flight in the aerodrome zone, approach, etc.). The listed data are known from regulatory documents and are entered by the crew into the aircraft on-board system before the flight.

The LTX database includes aircraft parameters, such as take-off mass, aerodynamic characteristics, lift coefficients, rate of climb, etc., necessary to generate control signals for maneuvering the aircraft to evade obstacles from the underlying surface at each flight stage. These data are contained in the flight manual of the aircraft and are also preliminarily entered by the crew into the on-board system.

After the formation of the source database and the start of the flight, the aircraft calculate the boundaries of the control zone 1.1 and the attention zone 1.2 (Fig. 1). Each zone is a three-dimensional region of space, the boundaries of which are determined depending on the mode and stage of flight.

In the vertical plane, the dimensions of the zones and the slope of the lower boundary of the zones (Fig. 1a) depend on the current flight parameters: ground speed, rate of change of the geometric height of the aircraft; from the strength and change of wind speed.

In the horizontal plane, the parameters and the geometric shape of the zones (Fig. 1b) depend on the ground speed and the angular velocity of the turn. When performing a U-turn maneuver, the lateral boundaries of the zones are increased toward the maneuver; also to increase the level of safety, the zones are expanded during flights in special conditions, such as, for example, mountainous terrain, poor visibility conditions, regardless of the magnitude of the angular speed of a turn.

In the construction of zones take into account the time parameters that are selected based on the requirements for safe maneuvering.

Detailed information on determining the parameters of the control zone and the zone of attention is presented in patent No. RU 2297047 dated 2005.08.03 (www.fips.ru).

To control the maneuver in the vertical plane, data are used on the relief elements and artificial obstacles located on the predicted trajectory in the horizontal plane, as well as near it. To calculate the predicted trajectory, proceed from the current rate ψ of the aircraft and its rate of change ω _y , which can be calculated from the angle of heel γ and the ground speed V _P according to the formula:

or obtained by differentiating the track angle by time, as well as by the signal of the yaw rate sensor.

From time to time, all the relief elements and artificial obstacles that are in the forecast area of the trajectory and fall into the control zone are viewed in the BDIS.

An element of the relief, as well as an artificial obstacle, is assigned the sign of an extreme obstacle when it is necessary to overcome it by increasing the vertical speed the greatest with respect to all other obstacles falling into the region of the motion forecast, the axis of which is the calculated trajectory in the horizontal plane. The obstacle retains the sign of extreme as long as it is in the indicated area or until an obstacle appears in it, requiring a larger increase in vertical speed. With each change of EP, the range D _{0 is} recounted and remembered, namely, the removal of the obstacle from the current location of the aircraft, its geometric height y _e , which is stored in the BDRPP, and the inverse flight time to the obstacle τ ₀ = D ₀ / V _P.

The flight of any aircraft takes place in conditions of uncertainty regarding the future impact of environmental influences. The most dangerous are changes in wind speed and direction, which cause loss of altitude. To account for this phenomenon, which is called wind shear, the minimum permissible obstacle span h _{md is} increased by an additional height margin h _ad numerically equal to the maximum height loss due to the action of an external disturbing medium. The minimum permissible clearance height h _md depends on the type of aircraft, its geometrical dimensions and design.

Nominal vertical coordinate of the aircraft at the time of flight

y _N = y _e + h _md + h _ad

recounted at each new identification of electronic signature.

For each type of aircraft, operational flight conditions are established, including the maximum wind speed.

Within these limits, the wind can vary in various ways. The greater the value of the additional margin h _ad , the lower the risk of collision with obstacles to the underlying surface due to height loss caused by the action of the external environment, but an increase in the margin leads to an increase in the nominal vertical speed and vertical overload when performing a maneuver, which increases the risk of reaching unacceptable angles attacks. The value of h _{ad is} calculated taking into account the error in measuring the flight altitude and the accuracy of its measurement.

Figure 2 shows the obstacle 2.1, the reference path 2.2, which is a straight line with an angle of inclination θ ° = arctan (y _М -y _g0 ) / D ₀ , where y _g0 is the geometric flight height of the aircraft at the moment of the maneuver, y _M = y _e + h _md . Figure 2 shows an approximate view of the nominal trajectory 2.3 in the vertical plane passing through the point with the vertical coordinate y _N , and examples of the real trajectory 2.4 (before the maneuver of the aircraft was in horizontal flight) and the real trajectory 2.5 (before the maneuver of the aircraft was reduced). The real trajectory usually differs from the nominal one due to the influence of a number of factors, for example, aircraft dynamics and external disturbances.

To check the realizability of the real trajectory, taking into account the constraints, the predicted obstacle clearance height is calculated, which cannot be less than the minimum acceptable.

The limit of permissible deviations from the nominal movement is determined, the presence within which is a guarantee of the successful completion of the vertical maneuver of avoiding encountering an obstacle.

An example of constructing the region of permissible deviations is given in Appendix 1.

It is known that to perform a maneuver in the vertical plane, a change in the lifting force is used for the aircraft of the aircraft scheme, including the civil aviation aircraft. For this purpose, the height controls are used, namely the elevators and the stabilizer; on the aircraft of the helicopter circuit, the rotor pitch controls and the swashplate.

With the selected control method, there is the most unfavorable change in wind disturbances in time, namely, the one that causes the greatest deviation from the unperturbed motion. The identification of the strength of wind disturbances is carried out in two ways, namely, indirectly by the presence and magnitude of deviations from the nominal movement, as well as directly by measuring and calculating changes in the components of the wind speed. A change in wind speed can occur at any time.

The reaction of the aircraft to these external influences, namely to changes in the speed and direction of movement of air flows, does not occur instantly, but is stretched in time. The rate of altitude loss depends on the dynamic characteristics of the aircraft, and in a controlled flight also on the effectiveness of control. The estimate of the reaction time to wind variations can be calculated (see patent No.RU 2297047 dated 2005.08.03, www.fips.ru) and confirmed by experimental data.

The control action generated in the process of reaching the nominal trajectory and stabilization on it must be adequate to the magnitude of the disturbances, and must also comply with design and operational restrictions.

For a flight along a nominal trajectory, it is necessary to maintain the nominal flight parameters: altitude, vertical speed and pitch angle.

With a low level of external disturbances or with their complete absence, namely when flying in a calm atmosphere, the most economical linear control laws are used, and the control signals are calculated in the form of a linear combination of deviations of the phase coordinates from their nominal values. Linear controls ensure the stability of dynamic systems and the smoothness of transients in them (see Appendix 1).

As indicated above, various types of interference significantly affect the performance of the evasion maneuver, among which the most dangerous is wind shear, namely, a change in the strength and direction of the wind. Such wind disturbances are very diverse and have a different nature, poorly predictable. These include, for example, microexplosions, wave disturbances, etc. [G.A. Filatov, G.S. Puminova, P.V. Silvestrov, Flight safety in a disturbed atmosphere. - M .: Transport, 1992. - 272 p.]. In all these cases, weather services can give a reliable forecast only regarding the range of changes in wind speed.

The purpose of this technical invention is that, in conditions of limited flight time to the detected extreme obstacle and previously known restrictions on wind disturbances, to build a vertical maneuver that ensures a guaranteed passage of the obstacle with a margin in height close to the minimum allowable.

To take into account the influence of weather conditions, weather forecast data are entered regarding the range of wind speed changes, aerodynamic coefficients of the aircraft are calculated for the current stage and flight mode, as well as restrictions on the parameters of movement, the characteristics of the nominal movement and the nominal trajectory are calculated, the flight along which guarantees the passage of the obstacle with an excess corresponding to the minimum permissible altitude for any changes in wind disturbances in the previously specified restrictions, at each time from the entrance to the zone board and before the flight of extreme obstacles calculate the controls that provide stabilization on the nominal path, generate electrical signals and feed them to the actuator controls LA, while the lateral movement parameters are kept constant. An example of compiling an equation for a specified nominal movement and calculating controls under extreme wind disturbances is illustrated in Appendix 2.

If there are devices on board that make it possible to calculate the wind speed and its change (see, for example, patent No. RU 2297047 dated 2005.08.03, www.fips.rn), or special warning systems for getting into the conditions of wind shear when they are triggered, they issue a command for increased engine thrust.

In manned aircraft, in the event of drive or steering unit failures, the director's control mode is used as a backup. The control signal is smoothed, scaled and fed to the flight control device in the form of a director index, the pilot of the aircraft, in accordance with the position of the command index, controls the aircraft, acting on its controls, and thereby ensures flight along a nominal path.

In automatic mode, a command signal is used to control the correct operation of the machine. An example of calculating a command signal is given in Appendix 1.

This technical proposal can also be implemented to control unmanned aircraft. In this case, control signals are generated in a land-based stationary or mobile flight control station and, using a data line, are transferred to an aircraft equipped with a transceiver, converted into electrical signals received by the actuators of the flight altitude and engine thrust control.

The claimed method of preventing a collision of an aircraft with obstacles to the underlying surface is implemented by the device, the structural diagram of which is shown in figure 3. The device contains a processor (P) 3.1, to which are connected the BDRPP 3.2, ANBD 3.3 blocks and the LTH LA database (LTH DB) 3.4, the current flight parameters block (TPP) 3.5, as well as a control and input panel for wind data (PU) 3.6. The processor outputs are connected to a control signal controller (CLC) 3.7, the outputs of which are connected to the inputs of the drives of the engine height and traction controls (POU) 3.9, and to the electrical signal generator (GS) 3.8, the outputs of which are connected to the inputs of the corresponding indicator equipment (IO) 3.10 . From a satellite navigation system such as GPS or GLONASS, the CCI 3.5 unit receives data on the current coordinates of the aircraft, namely latitude and longitude, geometric altitude, ground speed and ground angle. An inertial navigation system or a different type of navigation system can also be used as a source of information about aircraft motion parameters. A command to perform a maneuver is generated in the device at the entrance to the control zone with an alarm to the crew with a lead in time sufficient to make a decision.

The algorithm of the device shown in figure 4. To calculate the boundaries of the memory, the processor receives the corresponding parameters from the LTX LA 3.4, TPP 3.5 and PU 3.6 blocks to calculate these boundaries; data on possible obstacles are received from the BDLP 3.2 block, for each of which its latitude φ, longitude λ and height y are known _e . Then, according to the calculated parameters of the memory and the data on the heights and coordinates of the obstacles, those obstacles that fall within the limits of the memory are distinguished. If they do not fall further processing of these obstacles are not subject. When obstacles get into the memory, according to the data of the BDRPP 3.2 and TPP 3.5 blocks, an extreme obstacle is identified, its distance from the current location of the aircraft and its geometric height are remembered. If two or more extreme obstacles are found in the indicated area, then in the further work of the algorithm one uses whose removal is less.

A support trajectory is built over an extreme obstacle. The nominal path is built in accordance with the accepted control method. If maneuvering is not possible, namely due to flight performance and limitations, the predicted obstacle clearance height is less than the minimum acceptable, then a message is displayed informing you that it is necessary to choose a different trajectory in the horizontal plane. If deviations from the nominal parameters of the movement go beyond the limit of permissible deviations, as well as upon detection of a wind shear, a team is formed to increase the regime of aircraft engines. According to the current flight parameters, deviations from the nominal movement are determined, on the basis of which control actions are produced on the actuators of the pitch and engine traction controls.

The received control signals after smoothing and scaling are also served on the display of the flight control indicator (KPI).

An exemplary view of the KPI screen is shown in Fig. 5, where 5.1 is the silhouette of the aircraft, 5.2 is the horizon line, 5.3 is the vertical symbol, 5.4 is the pitch scale, 5.5 is the director's index, 5.6 is the warning zone, 5.7 is the heel scale, 5.8 is roll index, 5.9 - heading scale, 5.10 - symbol of the given direction, 5.11 - index of the actual directional angle, 5.12 - heading counter, 5.13 - vertical speed scale, 5.14 - vertical speed reference index, 5.15 - vertical speed counter, 5.16 - hazardous proximity signaling device with the ground, 5.17 - scale of angles of attack, 5.18 - reference index at head of attack, 5.19 - index of the maximum permissible angle of attack, 5.20 - deviation scale from the nominal path, 5.21 - deviation index from the nominal path, 5.22 - signaling area about the detection of electronic signals in the control zone, 5.23 - current distance to electronic signals in meters, 5.24 - height ES in meters, 5.25 - vertical overload counter, 5.26 - geometric height in meters.

The proposed method for preventing collisions of various types of aircraft with terrain elements and ground-based artificial obstacles, which consists in automating the process of calculating and executing a vertical evasion maneuver in conditions of extreme, namely worst wind disturbances, as follows from the description materials, ensures the full achievement of the goal, namely, reduction the risk of an aircraft collision with ground obstacles, taking into account the influence of wind effects and the human factor.

Annex 1

LINEAR CONTROLS

Necessary conditions for the physical realizability of the vertical maneuver of avoiding a collision with obstacles 6.1, taking into account restrictions on the available overload η _y , as well as on the maximum

vertical speed V _{ym are} illustrated in Fig.6 and have the form:

,

.

,

.

Here

,

,

D ₁ = D ₀ -Rθ ₀ , y ₁ = y ₀ -0.5Rθ ₀ ² ,

y ₀ - the height of the aircraft at the beginning of the maneuver, V _P - ground speed,

D ₂ = D ₁ -Rθ _M.

The equation of the lower limit of permissible deviations 6.4:

(R + y ₁ -y) ² + (D ₁ -D) ² = R ² for D ₀ >D> D ₂

y = y _M -θ _M D for D ₂ ≥D≥0.

If the flight is carried out in calm conditions and the weather forecast is favorable, then when calculating the nominal trajectory 6.3, the additional margin in height h _{ad is} assigned to be sufficiently small and, in particular, equal to zero, in this case the nominal trajectory will coincide with the reference 6.2. If there is a danger of falling into the conditions of wind shear, then the value of h _ad is increased in advance.

When an extreme obstacle is detected, h _{ad is} assigned the maximum value and h _ad0 = h _{ad is} stored. Provided there is no wind shear, and / or when deviations from the nominal trajectory are small, the value of the reserve changes in accordance with the dependence:

h _ad = h _ad0 (1-exp (-τ / T _e ) + exp (-τ ₀ / T _e )), 0≤τ≤τ ₀ .

Moreover, the reverse time moment τ _{0 of the} beginning of the indicated change is fixed, and the value of the equivalent time constant T _e depends on the type of aircraft, as well as the stage and flight mode, and relates to flight performance.

In accordance with the claimed technical solution for weak external disturbances, as well as for their complete absence, it is proposed to use a linear control law with restrictions, which, for example, has the following form:

U ₁ = F (k ₁ Δy + k ₂ ΔV _y ) -k ₃ ω _z .

The control signal U _l in accordance with the above formula represents the algebraic sum of two terms, the first of which is a limited sum of deviations from the nominal trajectory Δy = yy _N in height and

ΔV _y = V _y -V _yN in vertical velocity multiplied by the corresponding coefficients k ₁ and k ₂ , and the second term is the pitch speed multiplied by its coefficient k ₃ . The limiting function F makes it possible to limit the magnitude of the vertical overload η _y . In the control law, terms can additionally be introduced to ensure the reduction of static and dynamic errors.

The control signal generated in this way is fed to the actuator, namely the drive of the flight altitude control.

In real machines, the deviation angles of the flight altitude controls are also limited. All these restrictions reduce the risk of reaching critical angles of attack and thereby stall aircraft.

In the simplest case, the command signal in the operator record has the form:

where p is the differentiation operator, F _u (u) is the control signal limitation function u, ϑ is the pitch angle, T ₁ and T ₂ are the filter time constants, k ₄ and k ₅ are constant or variable coefficients.

Appendix 2

WARRANTY MANAGEMENT UNDER EXTREME CONDITIONS

WIND DISTURBANCES

The task of performing a vertical maneuver to avoid encountering an obstacle is proposed to be solved using the methods of controlling dynamic systems in conditions of uncertainty and conflict.

The movement of the aircraft in the vertical plane is described by a system of nonlinear differential equations of the form:

here y is the vector of phase coordinates, the components of which are the linear coordinates x _g , y _g , the components of the Earth’s speed V _xg , V _yg , pitch angle ϑ, pitch speed ω, deviations of the height controls δ _v and draft δ _p ; u is the vector of control actions in the form of electrical signals supplied to the drives of these controls; v is the vector of disturbing influences, which are taken as horizontal W _x and vertical W _y components of wind speed. The maximum wind speed is known in advance. The moment of appearance of the wind and the nature of its change are assumed arbitrary.

To find the control that the nominal trajectory must satisfy, when moving along it, the obstacle is guaranteed to pass at an altitude not lower than the minimum permissible for any wind changes within the specified limits, linearize the system (1) relative to the movement along the reference trajectory and obtain a system

where A, B, C - matrix of coefficients calculated on the basis of aerodynamic characteristics of the aircraft.

, соответствующая отклонению от опорной траектории по высоте. Фундаментальная матрица, как известно, является решением уравнения

при начальных условиях X(τ=0)=E,Using a nonsingular linear transformation (described, for example, in the book, Krasnovsky NN, Subbotin LI Positional differential games. - The main edition of the physics and mathematics literature of the Nauka publishing house, M., 1974. - p. 160) is introduced the new phase coordinate z = X _k x, where X _{k is the} k-th row vector of the fundamental matrix of the system

corresponding to the deviation from the reference trajectory in height. The fundamental matrix is known to be a solution to the equation

under the initial conditions X (τ = 0) = E,

where E is the identity matrix.

справедливо уравнение:For the system

the equation is true:

.

.

Denote φ = X _k Bu + X _k Cv.

Extreme disturbance, by definition, minimizes the value of z, the control goal is the opposite. For extreme disturbance and optimal control,

,

,

, где u_m, ν_m - ограничения на управления и возмущения соответственно.

,

,

, where u _m , ν _m are the restrictions on the controls and disturbances, respectively.

Integrating the equation

under the initial conditions z ₀ = X _k x ₀ ,

, по определению

есть отклонение по высоте в момент пролета экстремального препятствия, т.е. при τ=0. Вид этой функции иллюстрирует график 7.1 на фиг.7.get function

, a-priory

there is a deviation in height at the time of flight of an extreme obstacle, i.e. at τ = 0. The appearance of this function is illustrated in graph 7.1 in FIG.

7.2, представляющий собой границу области допустимых значений фазовой координаты z. Если начальные условия таковы, что фазовая координата z при движении системы находится выше указанной границы Г(τ), то при любых изменениях ветра в заранее заданном диапазоне гарантируется проход препятствия на высоте не ниже минимально допустимой. Иными словами для обратного времени τ должно выполняться условие z(τ)≥Г(τ).7 shows a graph of dependence

7.2, which is the boundary of the region of admissible values of the phase coordinate z. If the initial conditions are such that the phase coordinate z during the movement of the system is above the indicated boundary Г (τ), then with any changes in the wind in a predetermined range, the passage of the obstacle at a height not lower than the minimum permissible is guaranteed. In other words, for the inverse time τ, the condition z (τ) ≥ Г (τ) must be satisfied.

обозначенный 7.3 на фиг.7, где

- соответствует наибольшему значению функции

в момент времени τ_m,

соответствует моменту времени τ=0, ε выбирают таким образом, чтобы указанная парабола не выходила за границу Г(τ). Если

<0, то нет гарантии в успешном завершении маневра.Parameter is calculated

indicated by 7.3 in Fig.7, where

- corresponds to the largest value of the function

at time τ _m ,

corresponds to the time instant τ = 0, ε is chosen so that the indicated parabola does not go beyond the boundary Г (τ). If

<0, there is no guarantee that the maneuver will be completed successfully.

, где

описывает квадратичную параболуThe nominal trajectory, passing arbitrarily close to the minimum permissible height of the obstacle, corresponds to the equation

where

describes a quadratic parabola

.

.

The view of this function is illustrated in graph 7.4 in FIG. 7.

. Такими свойствами обладает релейное управлениеTo ensure movement along the nominal path, control ũ must minimize the difference

. Relay control has these properties.

.

.

To stabilize on the specified nominal path, other well-known algorithms and control laws using deviations from the nominal movement can also be used.

Claims (5)

1. A method for preventing a collision threat of an aircraft equipped with actuators of flight altitude control elements, as well as actuators of engine thrust control elements with obstructions of the underlying surface, which consists in preliminarily forming a database of the relief of the underlying surface, an aeronautical database, and a flight database technical characteristics of the aircraft, during the flight, the boundaries of the attention zones and control zones adjacent to each other are calculated, and from For obstacles on the underlying surface, obstacles are identified that pose a threat of collision with the aircraft, namely, those that fall into the control zone and the attention zone, and the flight paths and aircraft evasion parameters, which exclude the aircraft collision with obstacles, are calculated taking into account all obstacles in control zone, and each calculated trajectory, eliminating the threat of a collision of an aircraft with an obstacle, is the axis of the corresponding forecast area of the two the pressure, the width of which depends on the speed and altitude of the aircraft, generate electrical control signals that are displayed using indicators to take them into account when the crew makes a decision to maneuver the aircraft, characterized in that for the calculated trajectory in a horizontal plane within the boundaries of the zone controls highlight an extreme obstacle located in the forecast area of the calculated trajectory, taking into account restrictions on the parameters of motion and disturbances, extrapolate the trajectory to the vertical plane and calculate the predicted height of the obstacle flight, calculate the minimum permissible flight height of the specified extreme obstacle, as well as the nominal height of the flight, calculate the parameters of the nominal flight path in the vertical plane, calculate the border of permissible deviations from the nominal path, the magnitude and control sign in height, depending from deviations from the nominal trajectory and parameters of the aircraft motion, electrical control signals are supplied the control device of the flight altitude control, and when the permissible deviations from the nominal trajectory go beyond the lower boundary, as well as when the aircraft’s flight speed decreases relative to the nominal one or when it falls into the wind shear conditions, a control signal is generated that transfers the engines to the maximum permissible thrust mode with output alarm to the crew, and if the predicted height of the flight of an extreme obstacle is less than the minimum acceptable, the vertical maneuver RA block and decide on a maneuver in the horizontal plane. 2. The method according to claim 1, characterized in that when flying in conditions of weak wind disturbances or in their absence, the control signal for height is calculated as the sum of deviations from the nominal path along the height, deviations from the nominal vertical speed and pitch speed, each these values are multiplied by constant or variable coefficients, depending on the type of aircraft and flight mode, and the specified amount or part thereof is limited in amplitude, the electrical signal is fed to the height control th flight, and the border of permissible deviations from the nominal trajectory is a line coinciding with the trajectory of movement with available vertical overload. 3. The method according to claim 1, characterized in that the weather forecast data on the range of changes in wind speed and direction is entered in advance, the aerodynamic coefficients of the aircraft for the current stage and flight mode are calculated, as well as restrictions on the motion parameters, the characteristics of the nominal movement and the nominal trajectory are calculated , the flight along which guarantees the passage of an obstacle with an excess corresponding to the minimum permissible height for any changes in wind disturbances in the previously specified restrictions, in each At the moment of time from the entrance to the control zone and to the flight of an extreme obstacle, the controls that provide stabilization on the nominal trajectory are calculated, the corresponding electrical signals are generated, and they are fed to the actuator controls of the aircraft. 4. The method according to claim 1, characterized in that the control signal is smoothed, scaled and fed to the flight director in the form of a director index, and the pilot of the aircraft, in accordance with the position of the command index, controls the aircraft, acting on its controls, and stabilizes aircraft on a nominal trajectory. 5. The method according to claim 1, characterized in that the control signals are generated in a land-based stationary or mobile flight control station and, using a data line, are transmitted on board an aircraft equipped with a transceiver, and converted into electrical signals supplied to the actuators altitude and engine thrust.

Images