RU2725640C1 - Approach method of unmanned aerial vehicle in emergency conditions - Google Patents

Abstract

FIELD: aviation.SUBSTANCE: invention relates to control systems of aircraft drone type (UAV). UAV landing approach method in emergency conditions consists in that the UAV output to the descending start point for the emergency landing on the unprepared platform in the horizontal plane is made along the trajectory. At that, the trajectory of the controlled UAV is corrected as it approaches the landing site, for which calculation of the required increment Δφ of the heading angle (mismatch parameter) of the controlled UAV is carried out according to the rule:(1)where(2),here φ is the current heading angle of the UAV;andare required elements of the UAV speed vector ;is a constant which determines the required flight trajectory of the UAV, which is found from solving the system of equations(3)whereare coordinates of the controlled UAV in the fixed OXY coordinate system associated with the emergency landing site, which is described by a rectangle of width h, at that, the UAV course angle correction begins at the moment of the emergency landing command reception, and stops at the beginning of the drop point.EFFECT: invention can be used in solving problem of UAV saving in emergency (emergency) situations, when flight is impossible to continue and emergency landing is required.1 cl

Description

The invention relates to the field of control systems for unmanned aerial vehicles of aircraft type (UAVs) and can be used to solve the problem of preserving UAVs in emergency (emergency) situations in which flight is impossible to continue and emergency landing is necessary.

Unmanned aerial vehicles are widely used in various tasks related to monitoring the earth's surface, natural zones or zones of settlements, etc. Flight in this mode is usually carried out at a constant height and at considerable distances from the take-off point. The flight route can be set in advance and stored in the onboard computer system, or adjusted from the control point of the operator’s commands over the air. In the event of an emergency (contingency) situation, when the UAV is located from the runway (runway) —the take-off location is considerable distances, the operator must decide to land the UAV on unprepared sites — forest clearings, sections in order to preserve the equipment and functional equipment roads, glades, etc. To perform the indicated landing, the operator must transfer the landing place (coordinates, sizes, orientation of the site, etc.) to the UAV, as well as information on how to reach it to the specified site (heading, altitude, or required flight path, etc.), provided that the operator knows the location (coordinates) of the UAV. The information transmitted on board the UAV will not only save the device itself and its airborne systems, but also prevent a threat to the safety of people and the settlements near which it is used.

UAV flight can be divided into take-off, en-route flight and landing. Landing consists of the stages: pre-landing maneuvering, approach and landing directly. In this case, the purpose of the approach is to bring the UAV to a given point in the airspace, which is located on the line coinciding with the continuation of the axis of the runway. This point is called the start point of decline (TNS), which is located at a set height relative to the end of the runway [1]. Successful completion of the landing largely depends on the accuracy of the UAV exit both to the line directed along the longitudinal axis of the runway and to the HPS.

It is worth noting that with regard to the considered methods of using UAVs, as well as taking into account the small altitudes and speeds of its flight, the HPS can be located at the end of the runway site and offset relative to its axis.

A known method of controlling an aircraft (LA), realizing the conclusion of the aircraft on a line directed along the longitudinal axis of the runway, when approaching [3]. This method is characterized in that the aircraft approaching is equipped with an airborne radar that measures the distance to the corner reflector or radio transponder and the heading angle to it. Knowing their own position, runway course and distance to the reflector (beacon), control signals are formed on board the aircraft to exit the aircraft on a given line. The disadvantage of the described method is that its implementation requires the presence of additional on-board equipment — a radar, which complicates the design of the aircraft, and ground-based equipment — a corner reflector or a beacon, which is absent on unprepared landing sites.

Known approach methods (RU 2 559 196, RU 2 341 774, RU 2 273 590, RU 2 156 720, RU 2 242 800), for the implementation of which additional radio equipment is also required, both airborne and ground. These methods cannot be applied to UAVs because of the impossibility of placing the specified additional avionics equipment on the UAV due to its significant weight and size characteristics, and the complete absence of additional ground equipment at unprepared sites selected by the operator for UAV landing. In the absence of additional equipment, these methods cannot be implemented.

The closest analogue to the proposed method is the invention RU 2 509 684, which describes a method of landing an aircraft in emergency conditions (options), which allows landing by aircraft in the event of failure of their on-board radio communications and automatic radio compasses or the failure of standard radio equipment of airfields (Radar, DPRM) due to the use of a warning for radar exposure (STR) of the aircraft and two continuously operating at separated frequencies, covered by the frequency range of STR, radio emission sources (IRI) placed at the positions of the driving radio beacons (far and near) ) and intended to be determined on board the aircraft; equipped with STR, the direction of the longitudinal axis of the runway, as well as special rules for the aircraft crew to perform approach maneuvers according to the information displayed on the STR indicator.

The disadvantage of this method is the need to use ground-based equipment - radio sources that emit signals to orient the aircraft. To receive these signals on each UAV, additional equipment is necessary, which complicates the design of the managed object.

The technical result of the invention is the possibility of landing unmanned aerial vehicles of aircraft type on unprepared sites in emergency (emergency) situations in which the flight cannot continue, due to the automation of the process of outputting UAVs to the HPS.

The claimed technical result is achieved due to the fact that when an emergency occurs during a UAV flight, the operator at the control point selects a UAV landing site, which is a rectangular horizontal section of terrain (highway, clearings, clearings, etc.), which is suitable to land a UAV on an airplane, and transmits its parameters aboard the UAV — the coordinates of the middle of the butt end of the site closest to the UAV, the width and length of the site, and the orientation of the site. Further, in the onboard computing system of the UAV, these data are processed, the required path of the output of the UAV in the HPS is built, which is recorded in the automatic control system (ACS). Then, the UAV is directly controlled by comparing the current flight path (determined by standard on-board means) with the desired path recorded in the ACS, and when they diverge, by generating a control signal for course correction.

The ability to achieve a technical result is due to the following reasons:

- no need to use additional onboard equipment UAV;

- invariance to the guidance method, which allows not to change the control system and algorithms of the applied control methods [3];

- a universal (of the same type) way of describing all areas suitable for landing, which makes it possible to apply traditional methods of controlling aircraft [4];

- a significant reduction in the load on the operator due to the lack of the need to manually build the required trajectory of the output of the UAV in the HPS.

угла курса (параметра рассогласования) управляемого БЛА производится по правилу:For such conditions, one of the possible UAV control methods providing its output to the HPS is a new method obtained on the basis of the mathematical apparatus of the dynamic inverse problem method [5], in which the trajectory of the controlled UAV is corrected for its output to the HPS by combining its velocity vector with tangent constructed to the desired trajectory. Calculation of the required increment $$\Delta \phi$$

course angle (mismatch parameter) of a controlled UAV is made according to the rule:

(1) $$\Delta \phi ={\phi }_T-\phi =\text{arctg}\left(\frac{{\upsilon }_2}{{\upsilon }_1}\right)-\phi ,$$

(1)

- требуемый угол курса БЛА, $$\phi$$

- текущий угол курса БЛА, переменные $${\upsilon }_1$$

и $${\upsilon }_2$$

- требуемые элементы вектора скорости БЛА, которые равны:Where $${\phi }_T$$

- the required angle of the UAV course, $$\phi$$

- current UAV course angle, variables $${\upsilon }_1$$

and $${\upsilon }_2$$

- the required elements of the UAV speed vector, which are equal to:

(2) $$\{\begin{array}{l}{\upsilon }_1=\frac{h}{\pi }\cdot \left(1+e^u\cos {\nu }_0\right),\\ {\upsilon }_2=\frac{h}{\pi }\cdot e^u\sin {\nu }_0.\end{array}$$

(2)

[6]:The elements of the UAV velocity vector are calculated by differentiating the parametric equations of equipotential curves describing the electrostatic field of the capacitor, in which the distance between the plates is $$h$$

[6]:

(3) $$\begin{array}{cc}\{\begin{array}{l}x=\frac{h}{\pi }\cdot \left(u+e^u\cos {\nu }_0\right),\\ y=\frac{h}{\pi }\cdot \left({\nu }_0+e^u\sin {\nu }_0\right),\end{array}& -\infty <u<\infty \end{array}$$

(3)

определяет искомую эквипотенциальную линию.where is the meaning $${\nu }_0$$

determines the desired equipotential line.

The calculations are performed in the constructed rectangular coordinate system OXY: the coordinate system is right, the center of coordinates is in the middle of the end face of the site closest to the UAV, the OX axis is directed along the axis of the landing site. All heading angles of the UAV are counted from the positive direction of the OY axis clockwise.

и $$u$$

при подстановке в систему (3) координат $$\left(x,y\right)$$

положения БЛА. Один из способов решения системы нелинейных уравнений описан в [7].The required UAV flight path is constructed by solving a system of nonlinear equations (3) with respect to the values $${\nu }_0$$

and $$u$$

when substituting the coordinate system (3) $$\left(x,y\right)$$

UAV provisions. One of the methods for solving a system of nonlinear equations is described in [7].

и $$u$$

используются в (2) для вычисления требуемых элементов вектора скорости БЛА.Values obtained $${\nu }_0$$

and $$u$$

are used in (2) to calculate the required elements of the UAV velocity vector.

Correction of the UAV heading angle begins when the operator receives an emergency landing.

Thus, in order to correct the course angle when approaching in the horizontal plane using the described method (1) - (3) on board a controlled UAV, it is necessary to take into account:

и $$y$$

, значение скорости $$V_{ЛА}$$

и текущий угол курса $$\phi$$

;1) UAV motion parameters - coordinates $$x$$

and $$y$$

, speed value $$V_{L\mathrm{AND}}$$

and current course angle $$\phi$$

;

2) the parameters of the place (site) for landing - the coordinates of the middle of the end face of the site closest to the UAV, the width and length of the site, the orientation of the site.

The values necessary for the implementation of (1) - (3) and constituting the first group of parameters are measured by regular means on board each controlled UAV, and the values making up the second group are determined at the operator’s control point and transferred to the UAV.

Correction of the angle of the course of the controlled UAV stops when the UAV flies the entire trajectory and reaches the point where the descent begins, which coincides with the end of the landing site.

The specificity of the described method is that as the required UAV flight paths, lines of equipotential curves are used that describe the electrostatic field of the capacitor. The indicated lines, firstly, are smooth curves, which allows them to be used as UAV flight paths, and secondly, based on the physical properties of the capacitor, all these lines pass between its parallel surfaces, which allows UAVs moving along such trajectories to appear on the selected the operator of the landing site, regardless of the initial position of the UAV.

The claimed technical result is provided by the proposed method (1) - (4) of UAV control, as well as by using a universal (of the same type) method for describing terrain sites for landing, which makes it possible to significantly reduce the time for constructing UAV flight paths by the operator, thereby reducing the load on it.

и $$y$$

БЛА, а также заданных оператором параметров прямоугольной площадки для приземления - координаты середины торца площадки, ближайшего к БЛА, ширину и длину площадки, ориентацию площадки, с использованием (3), вычисляются параметры нужной траектории полета (эквипотенциальной линии), затем с помощью (2) определяются значения переменных $${\upsilon }_1$$

и $${\upsilon }_2$$

, на основании которых и измеренного значения текущего угла курса $$\phi$$

с помощью (1) формируется сигнал требуемого приращения угла курса $$\Delta \phi$$

для БЛА, позволяющий двигаться БЛА по требуемой траектории для осуществления посадки.Thus, the specified technical result is achieved by the fact that based on the measured coordinate values $$x$$

and $$y$$

UAVs, as well as the parameters of a rectangular landing pad set by the operator for landing — the coordinates of the middle of the end face of the landing pad closest to the UAV, the width and length of the landing pad, the orientation of the landing pad using (3), the parameters of the desired flight path (equipotential line) are calculated, then using (2 ) the values of the variables are determined $${\upsilon }_1$$

and $${\upsilon }_2$$

based on which and the measured value of the current course angle $$\phi$$

with the help of (1) a signal is formed of the required increment of the course angle $$\Delta \phi$$

for UAVs, allowing UAVs to move along the required trajectory for landing.

It is important to note that the indicated method of trajectory control of an unmanned aerial vehicle does not depend on the size of the UAV, its functional purpose and can be used for UAVs of any departmental affiliation.

Literature

[1] Directory of pilot and navigator. Ed. merit military man. navigator of the USSR aviation lieutenant general M.V. Lavsky. - M .: Military Publishing House, 1974, p. 390

[2] Batenko A.P. Management of the final state of moving objects. M .: Soviet radio, 1977, 256 p.

[3] 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.

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

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

[6] Govorkov V.A. Electric and magnetic fields. M .: Energy, 1968.

[7] Bakhvalov N.S., Zhidkov N.P., Kobelkov G.M. Numerical methods. M .: BINOM. Knowledge Laboratory, 2008.

Claims (7)

A method of approaching an unmanned aerial vehicle (UAV) in emergency conditions, namely, that the UAV is brought to the start point of descent to make an emergency landing on an unprepared site in a horizontal plane along a path, characterized in that the path of the controlled UAV is corrected when it approaches to the landing site, for which the calculation of the required increment $$\Delta \phi$$

course angle (mismatch parameter) of a controlled UAV is made according to the rule: $$\Delta \phi ={\phi }_T-\phi =\text{arctg}\left(\frac{{\upsilon }_2}{{\upsilon }_1}\right)-\phi ,$$

(1) Where $$\{\begin{array}{l}{\upsilon }_1=\frac{h}{\pi }\cdot \left(1+e^u\cos {\nu }_0\right)\\ {\upsilon }_2=\frac{h}{\pi }\cdot e^u\sin {\nu }_0\end{array}$$

, (2) here $$\phi$$

- current angle of the UAV course; $${\upsilon }_1$$

and $${\upsilon }_2$$

- required elements of the UAV speed vector; $${\nu }_0$$

- a constant that determines the required UAV flight path, which is found from the solution of the system of equations: $$\begin{array}{cc}\{\begin{array}{l}x=\frac{h}{\pi }\cdot \left(u+e^u\cos {\nu }_0\right),\\ y=\frac{h}{\pi }\cdot \left({\nu }_0+e^u\sin {\nu }_0\right),\end{array}& -\infty <u<\infty \end{array}$$

(3) Where $$\left(x,y\right)$$

- coordinates of the controlled UAV in the fixed coordinate system OXY associated with the platform for emergency landing, which is described by a rectangle of width $$h$$

, while the adjustment of the angle of the UAV course begins at the moment of receiving the emergency landing command, and stops when it is at the point where the descent begins.