RU2681817C1 - Automatic control system of a course angle and limitation of heel angle of an aircraft - Google Patents

Abstract

FIELD: aviation.SUBSTANCE: system of automatic control of the angle of inclination and limitation of the heel angle of the aircraft contains a heading angle adjuster, four comparison elements, calculator of a given roll angle, algebraic selector of the minimum signal, computer autopilot roll angle, aileron servo, course angle sensor of the aircraft, roll angle sensor of the aircraft, setting device of the maximum angle of heel, setting device of the minimum angle of heel, the third element of comparison, algebraic selector maximum signal, connected in a certain way.EFFECT: required accuracy of limiting the angle of heel when the aircraft turns to a given course angle is provided.1 cl, 2 dwg

Description

The invention relates to the field of automatic control systems (ACS) course angle of the aircraft (LA).

Known self-propelled guns that ensure the development of a given angle of the aircraft, using an autopilot roll angle, affecting the angle of deviation of the ailerons of the aircraft, containing serially connected head angle adjuster, a comparison element, a calculator of a given roll angle, autopilot roll angle, aircraft and aircraft angle sensor having an output connected to the second input of the comparison element [V. Bodner Control systems for aircraft. - M.: Mechanical Engineering, 1973. - 506 p. Page 121, fig. 3.24] and [Mikhalev I.A., Okoyemov B.N., Chikulaev M.S. Automatic aircraft control systems. - M.: Mechanical Engineering, 1987. - p. 240. Page 234, fig. 15.13].

These self-propelled guns due to the astatism of the system provide good accuracy of maintaining a given value of the course angle. However, they do not allow to limit the maximum value of the angle of heel in the process of turning the aircraft.

Closest to the achieved technical result, selected as a prototype, a system is adopted for automatic control of the heading angle and limiting the normal overload of the aircraft, containing a series-connected heading angle, a first comparison element, a calculator of a given roll angle and a second comparison element, a series-connected calculator of autopilot angle roll, servo ailerons, aircraft and the angle sensor of the aircraft, having an output connected to the second input of the first comparison element, the roll angle sensor of the aircraft, having an output connected to the second input of the second comparison element and to the second input of the roll angle calculator autopilot, characterized in that it further comprises a series-connected maximum overload unit, a third comparison element, a limit machine calculator overload and algebraic selector minimum signal, the output of which is connected to the input of the calculator autopilot roll angle, the output of the second element of comparison p connected to the second input of the algebraic minimum signal selector, the output of the roll angle sensor is connected to the second input of the calculator of the overload restriction automaton, the aircraft’s normal overload sensor having an output connected to the second input of the third comparison element [Patent No. 2503585 of the Russian Federation for the invention: IPC 8 В64С 13 /eighteen. The system of automatic control of the heading angle and limitation of the normal overload of the aircraft / V.I. Petunin, L.M. Neugodnikova - Application No. 20112120843/11; Claim 05/21/2012. Zaregistr. in the State register of inventions of the Russian Federation 10.01.2014. Bull. No. 1].

This self-propelled guns provides good static and dynamic characteristics of the control channel for the aircraft heading angle, but does not allow limiting the roll angle value when turning (turning), which can lead to unacceptable aerodynamic characteristics of the aircraft and violating flight safety when turning with large roll angles.

As you know, one of the most important restrictions when flying an aircraft is to limit the angle of heel of the aircraft. Turning the aircraft in the horizontal plane requires the creation of a centripetal force directed to the center of curvature of the trajectory. The creation of such a force is possible due to the aircraft tilting at a roll angle [Aircraft mechanics: Flight dynamics / Ed. A.F. Bochkareva and V.V. Andrievsky. - M.: Mechanical Engineering, 1985. - 360 p. Page 108].

When turning the aircraft, the angle of heel should not exceed the maximum allowable value. For example, in the work [Nikolaev L.F. Aerodynamics and flight dynamics of transport aircraft: a textbook for universities. - M .: Transport, 1990 .-- 392 p. Page 216] it is shown that in order to ensure the comfort of passengers, according to ENLGS, at bends and turns, the angle of heel should not exceed 30 degrees. This roll angle corresponds to a normal overload n _ydop = 1.15.

It is known that when the aircraft tilts left or right, overload occurs, which is directed vertically upwards. In the system of automatic control of the heading angle and limitation of the normal overload of the aircraft selected as a prototype, the normal overload characteristic of maneuverable aircraft is considered. If we take a passenger plane, then at small roll angles, overload is within normal limits. From the overload value, one can determine the roll value and build a system without measuring normal overload, but with a limitation of the roll angle. When limiting the angle of heel, in contrast to normal overload, it can be negative and positive, therefore, when limiting the angle of heel, it is necessary to take into account both signs of the angle of heel.

The task to which the invention is directed is to increase the reliability of aircraft control and maintain favorable flight conditions for the crew and passengers.

The technical result is the provision of the necessary accuracy of limiting the angle of the roll when the aircraft is rotated to a predetermined course angle due to the inclusion in the system of channels of limiting the maximum and minimum roll angles using algebraic selectors of the minimum and maximum signals.

The problem is solved in that in the automatic control system of the heading angle and the roll angle limits of the aircraft, containing a series-connected heading angle meter, a first comparison element, a calculator of a given roll angle, a second comparison element and an algebraic minimum signal selector, series-connected roll angle autopilot calculator and aileron servo drive, the output signal of which determines the angle of deviation of the ailerons of the aircraft, the angle sensor of the aircraft ATA having an output connected to the second input of the first comparison element, the roll angle sensor of the aircraft, having an output connected to the second input of the second comparison element and to the second input of the calculator of the autopilot roll angle, in contrast to the prototype, series-connected roll angle adjuster is additionally introduced and a third comparison element, the output of which is connected to the second input of the algebraic selector of the minimum signal, sequentially connected to the minimum roll angle adjuster, four th element of comparison and algebraic selector maximum signal output of which is connected to the input of the calculator autopilot roll angle, and the second input of the algebraic selector maximum signal connected to the output of the algebraic selector minimum signal pickoff output roll of the aircraft is connected to the second inputs of the third and fourth comparison element.

The invention is illustrated by drawings.

In FIG. 1 is a structural diagram of the inventive system of automatic control of the angle and heading angle of heel of the aircraft.

In FIG. 2 presents the results of transient modeling: a - graphs of transient processes in self-propelled guns with a heading angle with limitation of a positive roll angle; b - graphs of transients in self-propelled guns with a heading angle with restriction of a negative roll angle.

A system for automatically controlling the heading angle and limiting the roll angle of the aircraft, comprising the heading angle adjuster 1 connected in series, the first reference element 2, the target angle calculator 3, the second reference element 4 and the minimum signal algebraic selector 5, the heel angle calculator 6 connected in series servo ailerons 7, the output signal of which determines the angle of deviation of the ailerons of the aircraft 8, the angle sensor 9 of the aircraft 8, having an output, is connected to the second input of the first element of comparison 2, the angle sensor 10 of the aircraft 8, having an output connected to the second input of the second element of comparison 4 and to the second input of the calculator of the autopilot of the angle of 6, characterized in that a series of connected maximum angle bank 11 and the third element of comparison 12, the output of which is connected to the second input of the algebraic selector of the minimum signal 5, the dial of the minimum angle of heel 13, the fourth element of comparison 14 and a the algebraic selector of the maximum signal 15, the output of which is connected to the input of the calculator of the autopilot roll angle 6, and the second input of the algebraic selector of the maximum signal 15 is connected to the output of the algebraic selector of the minimum signal 5, the output of the roll angle sensor 10 of the aircraft 8 is connected to the second inputs of the third 12 and fourth 14 elements of comparison.

Limiting the angle of heel in the given system is achieved by introducing into its structure channels of limiting the maximum and minimum angles of heel using algebraic selectors of the minimum and maximum signals.

The system of automatic control of the heading angle and limiting the roll angle of the aircraft operates as follows.

The signal of the set course angle ψ _back from the output of the heading angle 1 is fed to the first input of the first comparison element 2, the second input of which receives a signal of the current value of the heading angle ψ from the output of the heading angle sensor 9. In accordance with the deviation:

the current value of the angle of the course ψ from the given ψ _back in the calculator of the given angle of heel 3 the specified value of the angle of heel γ _{back is formed} , which

compared in the second element of comparison 4 with the current value of the angle of heel γ from the output of the sensor of the angle of heel 10. At the output of the second element of comparison 4, a signal is generated:

To build self-propelled guns with limited parameters of aircraft, you can use logical devices that implement algorithms for algebraic selection of control channels. Typically, the principle of selection is applied, according to which the parameter of the multidimensional control object is regulated, which is closest to the value determined by the control program [V. Petunin Synthesis of automatic control systems for aircraft with automatic machines for limiting the limiting parameters // Izv. universities. Instrument making. 2010. Volume 53. No. 10. - S. 18-24.]. Such selection is implemented using algebraic selectors.

In order for the adjustable parameters not to exceed the maximum permissible values (upper limit), the selector must skip the control signal corresponding to the minimum value of the control signal. Such selection is called minimum selection, and the selector is called the minimum control signal selector.

If the minimum parameter values are limited (lower limit), preference is given to the parameter regulator, which requires the highest control signal to be maintained, i.e. selection is carried out to the maximum. In this case, the maximum control signal selector is used.

Regarding the difference of the input signals ε = U ₁ -U _{2, an} expression describing the operation of the algebraic selector of two quantities is converted using the module extraction operation as follows:

where μ = 1 for the selector of the maximum signal; μ = -1 for the minimum signal selector.

Since in this case it is necessary to limit the maximum and minimum values of the angle of heel, then the algebraic selectors of the minimum 5 and maximum signals 15 should be used in the system under consideration.

The signal of the maximum value of the angle of heel γ _max from the output of the master unit of the maximum angle of heel 11 is fed to the first input of the third comparison element 12, the second input of which receives the signal of the current value of the angle of heights γ from the output of the angle sensor 10. At the output of the third element of comparison 12, the signal is generated:

which goes to the input of the algebraic selector of the minimum signal 5.

The signal of the minimum roll angle γ _min from the output of the setter of the minimum roll angle 13 is fed to the first input of the fourth comparison element 14, the second input of which receives the signal of the current value of the roll angle γ from the output of the roll angle sensor 10. The signal is generated at the output of the fourth comparison element 14:

which goes to the input of the algebraic selector of the maximum signal 15.

The output signal of algebraic selectors minimum 5 and maximum signal 15

fed to the input of the calculator autopilot roll angle 6, the output of which is fed to the input of the servo ailerons 7 of the aircraft 8.

Selectors are introduced into the self-propelled guns for smooth switching of control channels and provide in all operating conditions the control action of only one of several control channels that are included in the work depending on the operating mode of the control object. Moreover, each of the control channels operates autonomously and its parameters are usually selected without regard to interaction with other channels. This allows you to maintain the static accuracy and stability margins inherent in individual control channels.

Consequently, the algebraic selector provides a smooth switching from one channel to another, for example, from autopilot roll angle to automatic limit limiting roll angles and back to autopilot.

Analytical synthesis of the gear ratios of the autopilot and automatic controllers, taking into account the specified quality of self-propelled guns, can be carried out using the standard transition characteristics method [V. Petunin Synthesis of automatic control systems for aircraft with automatic machines for limiting the limiting parameters // Izv. universities. Instrument making. 2010. Volume 53. No. 10. - S. 18-24.]. In this case, the equality of the transfer functions of the original Φ (p) and the desired control systems Φ * (p) should be fulfilled:

Consider the synthesis of a static autopilot roll angle with tight feedback in the aileron servo loop.

The transfer function of the aircraft in roll angle γ when controlling ailerons δ _E :

where n _e and n ₂₂ are dimensionless coefficients.

We take the autopilot control law in the form of:

- передаточные числа автопилота.where k _γ and

- gear ratios of autopilot.

Then the transfer function of the closed roll angle control system according to the setting action is:

Since the difference in the orders of the polynomial polynomials of the denominator and the numerator of the transfer function of the considered system Φ _γ (p) is equal to two, then we set the desired transfer function of the system in the form:

where d is the relative damping coefficient; ω is the natural frequency.

. Выравнивая коэффициенты при соответствующих степенях оператора р, получаем систему двух уравнений с двумя неизвестными k_γ,

:Equate the transfer function of the system f _γ (p) to the desired transfer function

. Equating the coefficients for the corresponding powers of the operator p, we obtain a system of two equations with two unknowns k _γ ,

:

From here we find the gear ratios of the autopilot roll angle:

Next, consider the self-propelled guns at the angle of the aircraft. The relationship between the corners of the course and roll according to [Bodner V.A. Aircraft control systems: A textbook for students of aviation specialties of universities. M .: Engineering, 1973. - 506 s] is defined by the following expression:

Where

умноженное на коэффициент k* и передаточную функцию инерционного звена W_из(p), является задающим сигналом в канале крена, т.е.Heading mismatch

multiplied by the coefficient k * and the transfer function of the inertial link W _from (p), is the master signal in the roll channel, i.e.

If the transfer function of the inertial link is chosen by the inverse numerator of the expression W _ψγ (p)

then the transfer function of the closed-loop control system of the heading angle according to the setting action has the form:

Since the difference in the orders of the polynomial polynomials of the denominator and numerator of the transfer function of the considered system Φ _ψ (p) is equal to three, we set the desired transfer function of the system in the form:

where A ₁ and A ₂ are the coefficients of Vyshnegradsky; Ω is the natural frequency.

Выравнивая коэффициенты при соответствующих степенях оператора р, получаем систему трех уравнений:We equate the transfer function of the system Ф _ψ (p) to the desired transfer function

Aligning the coefficients for the corresponding powers of the operator p, we obtain a system of three equations:

From here we find the relationship between the parameters of the control channels for the course and roll angles:

or

Then, as a result of the synthesis, we obtain the following possible values of the ACS parameters:

если d=1, то А₁=А₂=4;from the relation

if d = 1, then A ₁ = A ₂ = 4;

если k*=1, то Ω=4;from the relation

if k * = 1, then Ω = 4;

получаем ω=8.from the relation

we obtain ω = 8.

The synthesis performed is confirmed by the results of transient simulation in the inventive system of automatic control of the heading angle and limitation of the roll angle of the aircraft, shown in FIG. 2, where the specifying effects of the channels: ψ _ass = 1; γ _max = 0.7; γ _min = -0.7.

Transients obtained in the ACS with a heading angle with an automatic roll angle limiter are satisfactory because they show the necessary accuracy of the roll angle limitation and good control quality - the smoothness and monotony of transients in the channel switching modes of the system.

So, the claimed invention allows, due to the introduction into the structure of self-propelled guns, the angle of LA of the machine automatic roll angle control using algebraic selectors of the minimum and maximum signals, to ensure the necessary accuracy of the roll angle control when controlling the heading angle.

Claims (1)

A system for automatically controlling the heading angle and limiting the roll angle of the aircraft, comprising a series-connected heading angle indicator, a first comparison element, a calculator of a given roll angle, a second comparison element and an algebraic minimum signal selector, serially connected calculator of an autopilot roll angle and aileron servo drive, the output signal of which determines the angle of deviation of the ailerons of the aircraft, the angle sensor of the aircraft, having an output connected to the second the first input of the first comparison element, the roll angle sensor of the aircraft, having an output connected to the second input of the second comparison element and to the second input of the roll angle calculator autopilot, characterized in that it is connected to the maximum roll angle adjuster and the third comparison element in series which is connected to the second input of the algebraic minimum signal selector, sequentially connected the minimum roll angle adjuster, the fourth comparison element and the algebraic selector Maximum Feed signal output coupled to an input of the autopilot roll angle calculator, and a second input of the algebraic maximum signal selector connected to the output of the algebraic minimum selector signal pickoff output roll of the aircraft is connected to second inputs of the third and fourth comparison element.

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