RU2581215C1 - Method for automatic control of aircraft at landing and system therefor - Google Patents

Abstract

FIELD: aviation.

SUBSTANCE: for aircraft landing signals radio altitude, vertical speed, a control signal to elevator and to control engine thrust, addition of corrective signals compensation of influence of wind on elevator and thrust control drive. Correcting signal to elevator is based on measurement of absolute difference and registered speed. Correcting signal to drive thrust regulator is based on measurement of difference of current and rated power of the aircraft, determined based on track and registered speed. System for aircraft landing comprises measurement system of flight parameters, device for generating control signals to elevator and drive engine thrust, respectively. Flight parameters measurement system comprises a radar altimeter, vertical speed transducer, vertical overload sensor, sensor of absolute speed, registered speed sensor. Device for generating control signals to elevator comprises a unit for generating complex exponential signal, two adders, programmer, differentiator, two height correction unit, two non-linear converter. Control signal generating device contains speed setting panel, an adder, non-linear converter, draught stabilisation unit, unit calculating preset energy aircraft computation unit current aircraft power comparator.

EFFECT: providing required accuracy of landing.

2 cl, 1 dwg

Description

The invention relates to the field of automatic control of an aircraft, in particular to control methods that provide automatic landing and leveling modes, and may find application in on-board automatic control systems for aircraft.

Known control systems in which the optimal control of the aircraft is carried out in accordance with the algorithm for predicting a miss of the touchdown point, which is based on a change in energy, as well as overload and weight of the aircraft (Utility model “Aircraft Control System” No. 31007 U1). A miss prediction error is indicated to the pilot, after which he makes a decision on the movement of the governing bodies by engine thrust. The specified control system does not take into account the type of wind disturbances, as well as changes in the magnitude and direction of the wind, which has a significant effect on the speed determining the landing distance and the rigidity of landing.

The objective of the invention is to develop a control method that improves the accuracy of landing and the level of safety when landing in an environment of intense wind disturbances and turbulent gusts.

EFFECT: increased control efficiency due to the possibility of automatic correction of the elevator deviation, as well as the formation of a variable height of “thrust drop” depending on the energy state of the aircraft in order to reduce the spread of touch points in range and vertical speed, which ultimately provides the required accuracy landing.

The claimed technical result in the proposed method for automatic control of an airplane during landing using the elevator and engine thrust regulator is achieved by the fact that the method based on the use of radio altitude, vertical speed, vertical acceleration, ground and instrument speed coming from the flight parameters measurement system to the computational flight control system, in which signals received from the flight parameter measurement system are processed and a control signal is generated on the drive elevator and control signal to the engine traction control drive, characterized by the fact that to ensure that the runway is touched by the main landing gear in the specified ranges in range and vertical speed under extreme disturbances, correction signals are added to the generated control signals to compensate for the adverse effects of wind, and compensation of the effect the elevator drive is carried out by using the first correction unit in the computer system, which operates according to speed signals and changes in the difference between the ground and instrument speeds, and the formation of a variable thrust dump height of the engines is carried out by using a second correction unit in the computer system that works by the difference between the current and estimated energy of the aircraft, where the current energy is determined based on the ground and instrument speeds, and the calculated energy is determined by based on the set instrument speed coming from the control panel.

The technical result for the automatic control system for an airplane during landing is achieved by the fact that the system includes a control panel for setting the flight speed, means for processing the signals coming from the flight parameters measurement system and generating control signals for the elevator and drive for the engine traction control, and means for generating control signals made in the form of a flight control computer system, consisting of a control signal generating device for the elevator control and a pho device generating a control signal to the drive of the engine traction controller, the device for generating a control signal to the elevator drive comprises a complex exponential signal generating unit, first and second adders, a programmer, a first differentiator, first and second elevator correction blocks, first and second non-linear converters, and a control signal generating device for an engine traction controller drive comprises a speed setting console, a third adder, a third non-linear converter, bl to thrust stabilization, a unit for calculating the set energy of the aircraft, a unit for calculating the current energy of the aircraft and a comparator, and in the device for generating a control signal for the elevator drive, the unit for generating a complex exponential signal at the first input uses a signal from a radio altimeter, at the second input uses a signal from a vertical speed sensor and at the third input it uses the signal from the first output of the vertical overload sensor, the output of the complex exponential signal generating unit is connected to the first the input of the first adder, which at the second input uses the signal from the first output of the vertical overload sensor, and at the third input uses the signal from the first output of the ground speed sensor through the second adder in series at the first input, the first differentiator, the first elevator correction block and the first nonlinear converter, at the fourth input of the first adder, the signal from the first output of the instrument speed sensor is used through series-connected in the direction I drove the second adder at its second input, the second correction steering unit height and a second nonlinear transformer, a fifth input of the first adder is connected to the programmer; in the device for generating a control signal to the drive of the engine traction regulator, the thrust stabilization unit is connected with its first input to the first output of the speed control panel through a third adder in series at the first input and a third non-linear converter connected to it in the signal direction, and the third adder uses the signal from the second output at the second input instrument speed sensor, the second input of the thrust stabilization unit is connected to the output of the comparator, which, through the unit for calculating the current energy of the aircraft at its first input The ode uses the signal from the second ground speed sensor and at its second input uses the signal from the third output of the instrument speed sensor, with its second input the comparator is connected to the speed control panel at its second output through the unit for calculating the set energy of the aircraft.

In the present invention, the automatic control system, unlike the prototype, analyzes not only the amount of energy, but also takes into account the type of wind disturbances, identifying constant wind shears or turbulent gusts, as well as changes in wind speed, without taking into account information about the weight, which is difficult to obtain on board. The system automatically generates control actions at the same time both on the engine traction and on the elevator, adjusting the descent path during the final stage of the approach.

The proposed method, implemented in the automatic control system, provides control at the final stage of the approach — leveling, which determines the touch characteristics of the runway (touch distance, vertical speed, pitch angle, etc.).

The control at the leveling stage, as a rule, is carried out according to the exponential law, formed as a linear combination of the geometric flight altitude and its derivative, with the use of additional information about the parameters of the center of mass of the aircraft and its position relative to the calculated touchdown point.

When performing automatic leveling, the vertical speed of the object is reduced from the value with which the aircraft decreases along the glide path to the vertical speed, which ensures safe contact of the landing gear with the surface of the runway.

формируется в функции отклонения от экспоненциальной траектории выравнивания, задаваемой соотношением между высотой полета над поверхностью ВПП и вертикальной скоростью сниженияSetpoint value of vertical acceleration $${\tilde{a}}_{\mathrm{at}s\mathrm{but}d}$$

is formed as a function of deviation from the exponential alignment path defined by the ratio between the flight altitude above the runway surface and the vertical descent rate

where ΔН _exp is the exponential alignment path;

H _PB - the height of the bottom point of the chassis above the runway surface according to the readings of the radio altimeter;

H _AC - the position of the asymptote of the exponent located below the runway level to obtain a given vertical speed of contact;

K _Vy is the gain;

- вертикальная скорость; $${\widehat{V}}_{\mathrm{at}}$$

- vertical speed;

, введенное в систему с целью сглаживания скачков при дифференцировании высоты полета в случае наличия нерегулярности рельефа перед ВПП.F _Vy - vertical speed signal limitation $${\widehat{V}}_{\mathrm{at}}$$

, introduced into the system with the aim of smoothing jumps during differentiation of flight altitude in the case of irregular terrain in front of the runway.

It is known that wind disturbances to a large extent influence touch characteristics. Depending on the magnitude of the wind, the flight speed, the values of the vertical descent speed, the pitch angles change, which directly determines the landing safety. Therefore, a very important problem is the compensation of wind disturbances.

Compensation of wind disturbances is made and is aimed at improving touch characteristics. Additional corrective signals, depending on the current wind disturbances, are provided for both the elevator and engine traction and are implemented based on:

- identification of wind shifts and gusts of wind and the formation of additional control signals to the elevator;

- selection of the height of the "gas discharge" depending on the level of energy of the aircraft at the current time to reduce the touch distance.

To generate compensation control signals to the elevator under the action of a constant and turbulent wind, an additional signal for compensating the constant component and gusts of tailwind is added to the total signal of the closed and open loop of the alignment algorithm

- сигнал компенсации постоянной составляющей и порывов попутного ветра;Where $${\mathrm{BUT}}_{\mathrm{at}s\mathrm{but}d}^{\mathrm{at}sR}$$

- signal compensation of the DC component and gusts of tailwind;

- заданное значение вертикального ускорения; $${\tilde{a}}_{\mathrm{at}s\mathrm{but}d}$$

- setpoint of vertical acceleration;

U _CR - a program signal forming a program alignment path depending on the height of the radio altimeter;

U _{w then} - the compensation component of wind disturbances in the form of gusts of turbulent wind;

U _{w vetr} - compensation component for the formation of control signals to the elevator and compensation of constant wind shears, which is calculated as follows:

where ΔV is the difference between the instrumental V _CR and track V _put speed

(ΔV = V _ave -V _put);

F ₁ - nonlinear function, depending on the direction and speed of constant wind.

Component U _{w then is} designed to generate control signals to the elevator to compensate for turbulent gusts of wind.

U _{w then} can be obtained by filtering the difference between the instrument and ground speed signals by an isodromic link with a time constant T _f

where P is the Laplace operator;

ΔV is the difference between the instrument V _CR and track V _put speed;

F ₁ is a nonlinear function depending on the direction and speed of a constant wind;

F ₂ is a nonlinear function having a limitation, a deadband, defining the size of gusts compensated by the elevator, and asymmetry in relation to compensation of associated or oncoming gusts.

In the general case, the form of the nonlinear functions F ₁ and F ₂ is determined by the type of aircraft, its aerodynamic properties - “volatility” or, conversely, the tendency to short landing, as well as coefficients that determine the interaction with the earth’s surface (coefficients that determine the interaction with the earth’s surface (coefficients the influence of the underlying surface)).

In order to reduce distances and to eliminate large variations in landing distance under the influence of wind and turbulent gusts, braking is formed at the end of the flight before touching the runway by command of the gas discharge of the propulsion system at a variable height based on the energy capabilities of the aircraft.

The transfer of the gas sector to the “low gas” position is performed by the automatic control system, as a rule, at a fixed height N _sbr ~ 3 m.

The introduction of a variable thrust dump height of the engines in the proposed control method is associated with the need to ensure the same change in flight speed in the alignment area, which is necessary to reduce the spread of the touch point in range.

To determine the energy capabilities of the aircraft, we determine the kinetic energy at the current time

Since the pilot sets a predetermined speed V _{pr ass} according to the manual for flight operation, depending on the weight of the aircraft, we can assume that

then

where k is an empirical coefficient;

V _{CR ass} - the instrument speed value set by the remote control (set by the pilot), an analog of the weight characteristic;

- квадрат значения текущей путевой скорости с учетом ветра. $$V_{P\mathrm{at}t}^2$$

- the square of the value of the current ground speed, taking into account the wind.

We perform the Lagrange expansion

where Vpr rear ¹ , Vpr rear ² , Vpr rear ³ - reference values of the instrument set speed, respectively, for the minimum, average and maximum weights;

Ek ₁ , Ek ₂ , Ek ₃ - calculated (by ratio 7) energy values, respectively, for the minimum, average and maximum weights.

Depending on the amount of energy, a command is formed to release gas during braking on landing, while the following conditions are met:

E _to > E _{to lager} and

| V _y | <| V _y1 |,

where E _to - the current value of energy;

V _y - the current value of the vertical speed;

V _y1 is the minimum value for forming a gas discharge command, determined by the results of mathematical modeling.

The proposed compensation of wind disturbances can be implemented in the automatic landing system in the form of devices that generate additional control signals to the elevator and into the thrust channel of the engine control levers.

The essence of the proposed solution is illustrated in FIG. 1 block diagram of an automatic control system.

The proposed automatic control system is a computing system consisting, according to the control method, of two functional parts - a device for generating a control signal to the elevator drive (2) and a device for generating a control signal to the drive of the engine traction control (3) and using the known parameter measurement system flight (1), including a radio altimeter (4), a vertical speed sensor (5), a vertical overload sensor (6), a ground speed sensor (7) and an instrument speed sensor (8) . The control signal generating device (2) contains a complex exponential signal generating unit (9), adders (10) and (11), a programmer (12), a differentiator (13), elevator correction blocks (14), (15) and non-linear converters (16), (17). The control signal generating device (3) comprises a speed control panel (18), an adder (19), a nonlinear converter (20), a thrust stabilization unit (21), a set airplane energy calculation unit (22), an airplane current energy calculation unit (23) and a comparator (24).

The control system by which the inventive method is implemented works as follows.

In the control signal generating device, the elevator drive (2) receives the signals from the radio altimeter (4), vertical speed sensor (5) and vertical overload sensor (6) as inputs to the complex exponential signal generating unit (9) as follows: at the first input - a signal of the aircraft altitude relative to the surface of the earth from a radio altimeter (4), to the second input, a signal of vertical flight speed from a vertical speed sensor (5), and to the third input, an overload signal from the first output of a vertical overload sensor (6). From the output of the complex exponential signal generating unit (9), the signal is supplied to the first input of the adder (10), its second input receives an overload signal from the second output of the vertical overload sensor (6). The signal from the first output of the ground speed sensor (7) and the signal from the first output of the instrument speed sensor (8) are respectively sent to the first and second inputs of the adder (11), and then to the differentiator (13), after which the signal is amplified in the correction unit (14 ), is limited in a nonlinear converter (16), from the output of which the first correction signal is supplied to the third input of the adder (10), the second correction signal from the output of the nonlinear converter (17), to the input of which the signal from the second output is supplied, is supplied to the fourth input an adder (11) reinforced in the correction unit (15). Based on the four signals entering the adder (10), the output signal of the elevator control device is generated. Adder programming is carried out by means of a programmer (12) connected to the fifth input of the adder (10).

In the device for generating a control signal to the drive of the engine traction controller (3) from the first output of the speed control panel (18), the set speed is supplied to the first input of the adder (19), the second input of which receives the current instrument speed signal from the second output of the sensor (7). The signal from the output of the adder (19) through the limiter (20) is fed to the first input of the thrust stabilization unit (21). At its second input, a second correction signal from the comparator (24) is received, formed on the basis of a comparison of the signals, one of which comes from the set energy calculation unit (22), the input of which receives the signal from the second output of the speed reference console (18), and the other the signal is from the current energy calculation unit (23), the first input of which receives a signal from the second output of the ground speed sensor (7), and the second - the signal from the instrument speed sensor (8). Based on the signals from the comparator (24) to the first and second inputs of the thrust stabilization unit (21), a thrust control signal is generated for the engines.

Claims (2)

1. The method of automatic control of the aircraft during landing using the elevator and engine traction controller, based on the use of radio height, vertical speed, vertical acceleration, ground and instrument speed, coming from the flight measurement system to the flight control computer system, in which the incoming from the system for measuring flight parameters, signals are generated and a control signal is generated on the elevator drive and a control signal on the drive of the engine traction regulator, characterized by the fact that to ensure that the runway is touched by the main landing gear in specified ranges in range and vertical speed under extreme disturbances, correction signals are added to the generated control signals to compensate for the adverse effects of wind, and the influence on the elevator drive is compensated by using in a computer system the first correction unit, working on the signals of the rate of change of the difference between the ground and instrument speeds, and the formation of a variable thrust dumping heights of the engines are carried out by using a second correction unit in the computer system that works by the difference between the current and estimated energy of the aircraft, where the current energy is determined based on the ground and instrument speeds, and the calculated energy is determined based on the set instrumental speed coming from the control panel. 2. The automatic control system for an aircraft at landing, including a control panel for setting the flight speed, processing means for the signals received from the flight parameters measurement system and generating control signals for the elevator and drive for the engine thrust regulator, while the means for generating control signals are designed as a computer system flight control, consisting of a device for generating a control signal to a rudder drive and a device for generating a control signal for a drive and engine thrusts, wherein the control signal generating device for the elevator drive comprises a complex exponential signal generating unit, the first and second adders, the programmer, the first differentiator, the first and second elevator correction blocks, the first and second nonlinear converters, and the control signal generating device for the drive of the engine traction controller contains a speed control panel, a third adder, a third nonlinear converter, a thrust stabilization unit, a set energy calculation unit an amoleta, a unit for calculating the current energy of the aircraft and a comparator, and in the device for generating a control signal for the elevator drive, the complex exponential signal generating unit uses the signal from the radio altimeter at the first input, uses the signal from the vertical speed sensor at the second input, and uses the signal from the third input the first output of the vertical overload sensor, the output of the complex exponential signal generating unit is connected to the first input of the first adder, which is used at the second input uses the signal from the first output of the vertical overload sensor, and at the third input uses the signal from the first output of the speed sensor through a second adder in series in the direction of the signal at its first input, the first differentiator, the first elevator correction unit and the first nonlinear converter, at the fourth input the first adder uses the signal from the first output of the instrument speed sensor through a second adder sequentially connected in the direction of the signal at its second input, the second block ok correction of the elevator and the second non-linear converter, the fifth input of the first adder is connected to the programmer; in the device for generating a control signal to the drive of the engine traction regulator, the thrust stabilization unit is connected with its first input to the first output of the speed control panel through a third adder in series at the first input and a third non-linear converter connected to it in the signal direction, and the third adder uses the signal from the second output at the second input instrument speed sensor, the second input of the thrust stabilization unit is connected to the output of the comparator, which, through the unit for calculating the current energy of the aircraft at its first input The ode uses the signal from the second ground speed sensor and at its second input uses the signal from the third output of the instrument speed sensor, with its second input the comparator is connected to the speed control panel at its second output through the unit for calculating the set energy of the aircraft.