RU2571845C1 - Control over drone flight path at flyby over terrain relief in vertical plane - Google Patents

Abstract

FIELD: aircraft engineering.

SUBSTANCE: claimed invention is meant for control over manned aircraft or drones in low-altitude flight with flyby over the set of obstacles in vertical plane. The flight is path is set with selected pitch angles. Selected path is corrected at approach to said set of obstacles to be approximated by semi-ellipse. Pitch angle increment is computed by a definite rule. Pitch angle is corrected in a definite way starting from the moment when the distance from controlled drone to the centre of approximating ellipse is smaller than preset magnitude.

EFFECT: higher survivability in low-altitude flight.

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Description

The invention relates to methods for trajectory control of unmanned aerial vehicles (UAVs) of both civilian and military purposes and can be used to increase their survivability when performing low-altitude flights.

Increasing the survivability of aircraft in the process of controlling an aircraft [1] is one of the main trends in the development of systems with UAVs. One of the ways to increase the survivability of UAVs during low-altitude flights (MVPs) in very rough terrain is to fly around obstacle groups in a vertical plane. In manned aircraft (LA), a special radar system is used to carry out the MVP over rough terrain - the low-altitude flight electronic control system (RES MVP), the main task of which is the formation of a specialized aircraft flight, in which the flight path of the aircraft repeats the terrain profile. It is important to note that RESU MVP should provide a solution to problems at any time of the year, day or in any weather conditions. These requirements predetermine the multichannel principle of constructing a computing system for a radar system using radar to determine the distance to obstacles and radio altimeters to control the current altitude [2]. Thus, the composition of the specified system includes equipment that is characterized by sufficiently large weight and size and cost characteristics. Obviously, the use of a similar complex as part of the onboard equipment of the UAV seems inappropriate according to the criterion of "cost-effectiveness". In addition, when solving some special problems, the use of an active radar is not recommended, since this can serve as a strong unmasking factor.

In existing systems with UAVs [2] (see Fig. 1), including a control point 1 and an unmanned aerial vehicle 2, as a rule, the route method is used, which is carried out in two stages, to fly over uneven terrain 3 during low-altitude flight. At the first (preparatory) stage, the dispatcher (operator, combat control officer) is scheduled for a number of control points 4, which the UAV must pass with a given pitch angle. Further, to ensure consistent UAV passage of the designated points in the navigational calculation, guidance algorithms for stationary targets (alternately for each corresponding control point) are implemented. At the second stage, the aircraft 2 is directly controlled to bypass the obstacle group in the vertical plane 3 along the calculated trajectories 5 using control commands from the control room (command) point 1. The procedure for the existing method of flying around an obstacle group by the aircraft is illustrated in FIG. one.

It should be noted that this method of flying around obstacle groups associated with the application of control points involves the direct participation of a person and is a rather laborious task, since such actions must be performed for each UAV. Moreover, the application of such points requires extensive experience with the operator and, in the general case, this is a non-trivial task.

The technical result of the invention is to increase the survivability of the UAV through the use of command control and automation of the process of flying around groups of obstacles in a vertical plane at low altitude flight of the UAV along the planned route.

The claimed technical result is achieved due to the fact that when planning a UAV flight route, each obstacle of the group in the vertical plane is approximated by a semi-ellipse, that is, half of the ellipse located in the upper part of the OXY coordinate plane, one of the axes of which lies on the OX axis (coinciding with the zero distance). The center and axes of such a semi-ellipse are the center and axes of the ellipse generating it, respectively. The operator for describing the selected obstacle indicates only the center of such a semi-ellipse and the values of its semi-axes. Next, the aircraft is directly controlled by bypassing obstacle groups by correcting the calculated guidance trajectory.

The possibility of achieving a technical result is due to the following reasons:

- a significant reduction in the time the operator describes the obstacles, which reduces the load on the operator (combat control officer) [3];

- a universal (of the same type) way of describing obstacles, which makes it possible to apply traditional methods of controlling aircraft [2].

A variant of the mutual arrangement of the steered aircraft and the group of obstacles is illustrated in FIG. 2, on which the aircraft moves uniformly with a speed of V _LA linearly and parallel to the earth's surface at a given height N. Obstacles of various configurations are arranged in groups.

For such conditions, one of the possible control methods that increases the survivability of an unmanned aerial vehicle is a new method, obtained on the basis of the mathematical apparatus of the dynamic inverse problem method [4], in which the trajectory of a controlled UAV is corrected when it approaches a group of obstacles by combining its speed vector with tangent plotted to the desired path. The calculation of the required increment of the pitch angle (the parameter of the mismatch between the required and the current pitch angle) of the controlled UAV is made according to the rule:

where the variables w ₁ and w ₂ are calculated by differentiating the function ψ (x, y) from the coordinates of the UAV. The OXY coordinate system is chosen so that the coordinate y corresponds to the flight altitude, and the direction of the x coordinate axis corresponds to the flight direction of the UAV. The expression for the variables w ₁ and w ₂ has the form:

The function ψ (x, y) is the stream function of the ideal fluid flow around several elliptical cylinders, which can be obtained on the basis of the theory of functions of a complex variable and the expression for the complex potential of the circulationless flow around elliptical cylinders, being selected as its imaginary part.

The expression for the complex potential and the dependence for the stream function and the velocity potential of the resulting ideal fluid flow, in turn, using the conformal mapping of the exterior of the contour of an elliptical cylinder to the exterior of a circular cylinder [5, 6] in the case under consideration are written as follows:

, $$Q_i=\sqrt{{\left(z-z_{0i}\right)}^2-\left(a_i^2-b_i^2\right)}$$

, Where $$R_i=\frac{\mathrm{one}}{2}\left(a_i+b_i\right)$$

, $$Q_i=\sqrt{{\left(z-z_{0i}\right)}^2-\left(a_i^2-b_i^2\right)}$$

,

z = x + iy is the complex variable on the complex plane OXY, N is the number of semi-ellipses approximating obstacles, V _LA is the speed of the UAV at an infinitely large distance from semi-ellipses, a _i and b _i are the values of the semi-axes of the i-th semi-ellipse; z _0i are the coordinates of the center of the ith half-ellipse in the selected coordinate system OXY.

The indicated parameters are determined either at the control room (command) point, or directly on board the UAV.

The UAV pitch angle correction begins when the distance from the controlled UAV to the center of the semi-ellipse approximating the obstacle becomes less than a certain value:

where x _P and y _P - coordinates of the center of the semi-ellipse approximation; x and y - UAV coordinates; L is the given distance.

An exemplary view of the trajectory of the flyby 7 of a group of obstacles that are approximated by half ellipses 6 is shown in FIG. 3. The required increment Δϑ of the pitch angle (mismatch parameter) of the controlled UAV formed according to rule (1) is also shown here.

Thus, to correct the pitch angle when flying around obstacle groups in a vertical plane using the described method (1) - (4), it is necessary to take into account:

1) Motion parameters BLA - coordinates x and y, the value of the velocity V and the current _aircraft pitch angle θ;

2) the parameters of the obstacle groups - the coordinates of the centers of the semi-ellipses of the approximation z _0i and the values of their semi-axes a _i and b _i .

The values necessary for the implementation of (1) - (4) and making up the first group of parameters are measured both by regular means at the control rooms (command) points, and on board the UAV, and the values making up the second group are located in the memory of the KP VP computer, where they are entered directly by the dispatcher (operator, combat control officer).

The pitch angle correction of the controlled UAV stops when its height becomes equal to the initial (predetermined) flight height H of the unmanned aerial vehicle, determined by the planned flight route.

The specificity of the described method is that the dependencies (1) - (4) are based on the approximation of groups of obstacles in the vertical plane. This approach allows you to unify and automate the process of describing the folds of the terrain and other obstacles, thereby significantly reducing the burden on the dispatcher (operator, combat control officer).

The claimed technical result is provided by the proposed method (1) - (4) for controlling an unmanned aerial vehicle, as well as using a universal (of the same type) method for describing obstacle groups in a vertical plane, which makes it possible to significantly reduce the time for describing a relief by a dispatcher (operator, combat control officer), thereby reducing the load on it.

Thus, the indicated technical result is achieved by the fact that, based on the measured values of the flight speed V of the _aircraft and the flight height H of the unmanned aircraft, as well as the coordinates of the centers of approximation half-ellipses and their half-axes specified by the dispatcher (operator, combat control officer) using (3), it is calculated stream function ψ (x, y). Then, using (2), the values of the variables w ₁ and w _{2 are} determined, based on which and the measured value of the current pitch angle ϑ, using (1) a signal is generated of the required increment of the pitch angle Δϑ for the UAV, which allows flying around a group of obstacles.

It is important to note that this method of trajectory control of an unmanned aerial vehicle can be implemented in two modes:

1) in command guidance mode, in which the parameters of the movement of the controlled aircraft — the speed value and the value of the UAV coordinates — are determined at the control room (command) control point;

2) in stand-alone mode, in which the parameters of the movement of the controlled aircraft — the speed value and the value of the UAV coordinates — are determined directly on board the UAV.

In this case, the value of the current pitch angle ϑ in both cases is measured only on board the UAV.

This circumstance makes it possible to use the described control method for correcting the flight paths of aircraft of both civilian and military aviation when they fly around obstacle groups in a vertical plane during low-altitude flight.

Literature

[1] Verba V. S. Aviation complexes of a radar patrol and guidance. Status and development trends. M .: Radio engineering. 2008.432 s.

[2] Aircraft radio control systems. T. 3. Command radio control systems. Autonomous and combined guidance systems / V.I. Merkulov, A.I. Kanashchenkov [et al.]. M .: Radio engineering, 2004.317 s.

[3] Air defense of Russia and scientific and technological progress. Combat complexes and systems yesterday, today, tomorrow / E.A. Fedosov [et al.]. M.: Bustard, 2001.

[4] Krutko P.D. Inverse problems of dynamics in the theory of automatic control. M .: Engineering, 2004.

[5] Loytsyansky L.G. Mechanics of fluid and gas. Fizmatgiz, 1959.

[6] Lavrentiev M.A., Shabat B.V. Methods of the theory of functions of a complex variable. M .: Nauka, 1965, 716 p.

Claims (1)

The method of controlling manned and unmanned aerial vehicles (UAVs) during low-altitude flight with flying around obstacle groups in a vertical plane from the control room (command) point (UA), which consists in the fact that the UAV is brought to the planned rectilinear and parallel to the earth’s surface flight path flying around a group of obstacles with given pitch angles, characterized in that the trajectory of the controlled UAV is corrected when it approaches a group of obstacles, each of which it is oxidized by a semi-ellipse, for which the calculation of the required increment of the pitch angle (the parameter of the mismatch between the required and the current pitch angle) of the controlled UAV is performed according to the rule:

Where

here w ₁ and w ₂ are the components of the velocity vector of the controlled aircraft, ψ (x, y) is the coordinate function x and y of the controlled UAV in the fixed coordinate system OXY, defined as the imaginary part of the expression for the complex potential:

Where $$R_i=\frac{\mathrm{one}}{2}\left(a_i+b_i\right)$$

, $$Q_i=\sqrt{{\left(z-z_{0i}\right)}^2-\left(a_i^2-b_i^2\right)}$$

, z = x + iy is the complex variable on the complex plane OXY, N is the number of semi-ellipses approximating obstacles, V _LA is the speed of the UAV at an infinitely large distance from the semi-ellipses, a _i and b _i are the values of the semi-axes of the i-th semi-ellipse; z _0i are the coordinates of the center of the ith half-ellipse in the selected coordinate system OXY, while the UAV pitch angle correction begins when the distance from the controlled UAV to the center of the semi-ellipse approximating the obstacle becomes less than a certain value L:

where x _P and y _P are the coordinates of the center of the semi-ellipse of approximation, x and y are the coordinates of the UAV, and is carried out until the time when the UAV flight height becomes equal to the initial height N.

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