RU2490168C1 - Semiautomatic system for prevention of aircraft pitch angle drift beyond operating range - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to aircraft engineering, particularly, to landing control system. Proposed system comprises robot pilot, elevator drive, sequentially connected control stick and remote control system and aircraft flight parameter transducers. It differs from know design in that proposed system additionally incorporates signal selector, switch comparator, setter of magnitude of signal selector actuation height. Note here that signal selector generates signal to drive elevator so that in drift of aircraft pitch angle beyond operating range, control is changed to automatic control over pitch angle to limit control affects of the pilot inadequate to current conditions that may cause emergent conditions. Said system eliminates negative tendencies in aircraft flight dynamics as to pitch by active interference into control.

EFFECT: higher flight safety.

11 dwg

Description

The invention relates to aviation, and in particular to semi-automatic control systems.

According to the statistics of flight accidents, approximately half of the accidents and accidents of passenger aircraft occur at landing. One of the directions for solving this problem is the automation of the indicated phase of the flight and comprehensive control of the pilot's actions by the on-board display and alarm systems. The main controlled parameters include the pitch angle of the aircraft - the angle between the axis of the aircraft and the surface of the earth.

The pitch angle is changed by deflecting the elevator (RV). Landing a land plane with a large pitch angle is fraught with the touch of the runway (runway) with the tail of the plane. For a seaplane, not only during splashdown, but also when moving on water (gliding), it is necessary that the pitch angle does not exceed a certain value, forming the so-called The “upper” boundary of hydrodynamic stability, beyond which entails a loss of longitudinal stability of the seaplane. Thus, there is an operational limitation of the pitch angle “from above”.

Landing with a small or negative pitch angle, firstly, can cause the runway to touch the front landing gear, which is highly undesirable. Secondly, a small or negative pitch angle implies a negative vertical speed of the aircraft (speed of descent). With a large negative value of the vertical speed at the moment of touching the runway, landing occurs “roughly” and can lead to disaster. Similarly to the “upper” boundary of hydrodynamic stability, seaplanes are characterized by the so-called. “Lower” border, when the value of the pitch angle is small and can lead to a loss of lateral stability. Thus, the operational limitation of the pitch angle “from the bottom” is no less important, from the point of view of ensuring the safety of the aircraft landing.

A known system for preventing stalling an aircraft, designed to prevent entry into a dangerous mode (1). The principle of operation of this system is that if the value of the controlled parameter (angle of attack) becomes close to limiting, the gear ratio between the rotary switch and the control handle (RU) decreases. However, despite the fact that a decrease in the degree of response of the aircraft to the control action should signal the pilot about the approach of a dangerous mode, the probability of reaching this mode remains, because this decrease does not change the undesirable trends in the dynamics of the aircraft. A similar system is analogous to the intended invention for its intended purpose (limiting the kinematic parameters of the movement of the aircraft).

There is also a system of automatic control (ACS) of pitch and limit of angle of attack of an aircraft (2), which in addition to pitch adjuster, pitch angle sensor, pitch autopilot calculator and elevator servo also includes an algebraic maximum signal selector and constraint calculator angle of attack. The essence of this system is that the algebraic selector switches its inputs and outputs in such a way that when the autopilot emits a pitch signal less than that received from the automatic machine for limiting the angle of attack, the elevator control is transferred to the latter (automatic machine), and the pitch autopilot is excluded from control loop. Such a system is an analogue of the alleged invention according to the method for implementing the mechanism for limiting the kinematic parameters of the movement of the aircraft using a signal selector. However, modern self-propelled guns, even on aircraft equipped with complex airborne systems, as a rule, do not provide automatic landing. Therefore, the final stage of landing should be carried out with the participation of the pilot, therefore, the longitudinal control system should be semi-automatic.

Closest to the technical result achieved, chosen as a prototype, is a system for automatically removing the aircraft from the maximum allowable angle of attack (3), containing a control signal generation module, electrically connected to an indication generation unit, which is connected to a search and recommendation module, flight information indicator and indicator of the information management field. In addition, it contains a voice informant, manual and foot controls on pitch, roll and heading channels, actuators on these control channels, characterized in that it includes an aerodynamic flight parameter analysis (BAAPP) unit that is electrically connected to the angle of attack sensor , a module for generating control signals, a unit for recording flight parameters, an autopilot, an automatic traction control, manual and foot controls, and their actuators. In this system, the BAAPP, in case of exceeding the permissible angle of attack by 1 degree, disconnects the control lever from the pitch channel and transfers the elevator to a shallow dive, and when the aircraft reaches a negative angle of inclination of the trajectory set in the program, control is transferred to the autopilot, which is turned into stabilization angle of inclination of the trajectory. When the aircraft reaches the most favorable angle of attack, the BAAPP switches the autopilot to the mode of stabilization of altitude, roll and course, and also includes a control lever in the pitch channel, i.e. returns the pilot to the control loop.

Thus, the described system not only limits the pilot's control actions leading to the achievement of a critical angle of attack, but also eliminates undesirable trends in the dynamics of the aircraft by actively intervening in control.

However, the way to implement the mechanism for limiting kinematic parameters in the form of a block that forms a sequence of control actions “on a shallow dive”, “stabilization of a given negative angle of inclination of the trajectory” and then transfers control to the pilot is not acceptable when implementing restrictions on the maximum and minimum pitch angle.

The technical result of the alleged invention is expressed in increasing the flight safety level of the aircraft by creating a semi-automatic system to prevent the aircraft pitch angle from exceeding the operational range, which would not only limit pilot control actions that are inadequate to the current situation and lead to an emergency, but also eliminate undesirable trends in the dynamics of the aircraft in pitch by actively intervening in control.

The technical result is achieved by the fact that in the aircraft control system comprising an autopilot, elevator drive, a control stick and an electrical remote control system connected in series with the aircraft motion parameters sensors, a signal selector, a switch, a comparison unit, a height switch for adjusting the signal selector height are also included . In this case, the first input of the signal selector is connected to the output of the remote control system. The second and third inputs are respectively connected to the outputs of the stabilization subsystems of the maximum and minimum pitch angles of the autopilot, and the output of the signal selector is connected through a switch to the elevator control. Moreover, the other input of the switch is connected to the electrical control system, and the third, control input of the switch is connected to the output of the comparison unit, the first input of which is connected to the output of the set point of the height of the signal selector, and the second input is connected to the output of the sensors of the aircraft motion parameters.

The main difference between the proposed system and the prototype is that it includes a signal selector that generates a signal for the RV drive in such a way that when the pitch angle of the aircraft leaves the operating range, control is transferred to the pitch angle automatic control system.

The present invention has novelty, inventive step and industrial applicability.

The essence of the alleged invention is illustrated by drawings, where:

- figure 1 shows a structural diagram of the proposed semi-automatic system to prevent the exit of the pitch angle of the aircraft beyond the operational range;

- figure 2 - the results of mathematical modeling: stroke control knob;

- figure 3 - the results of mathematical modeling: pitch angle (without signal selector);

- figure 4 - the results of mathematical modeling: pitch angle (with signal selector);

- figure 5 - the results of mathematical modeling: the angle of the deviation of the PB (without signal selector);

- figure 6 - the results of mathematical modeling: the deviation angle of the PB (with a signal selector);

- Fig.7 - the results of mathematical modeling: stroke control sticks;

- on Fig - the results of mathematical modeling: pitch angle (without signal selector);

- figure 9 - the results of mathematical modeling: pitch angle (with signal selector);

- figure 10 - the results of mathematical modeling: the deviation angle of the PB (without signal selector);

- figure 11 - the results of mathematical modeling: the deviation angle of the PB (with a signal selector).

A semi-automatic system for preventing the aircraft’s pitch angle beyond the operational range (Fig. 1) is formed on the basis of an autopilot stabilizing a given pitch angle and includes an autopilot 1, an elevator wheel drive 2, serially connected control knob 3 and the EMF 4, to the input of which, as and at the input of the autopilot 1, signals are received from the sensors of the parameters of the movement of the aircraft 5. In addition, it includes a signal selector 6, the first input of which is a signal from the EMF 4, with the second and third input respectively connected the outputs of the stabilization subsystems are maximum 7 and minimum 8 pitch angles of autopilot 1, and the output of the signal selector 6 is connected via switch 9 to the elevator 2 drive, the other input of switch 9 is connected to the EMF 4, and the third, control input of switch 9, is connected to the output comparison unit 10, which compares the height of the inclusion of the signal selector 6, coming from the corresponding setter 11 to the first input of the comparison unit 10, and the current flight height, coming to the second input of the comparison unit 10 from the sensors in the movement of the aircraft 5.

The essence of the invention lies in the fact that the value of the signal controlling the RV 2 drive and coming from the RU 3 through the EMF 4 is compared in the selector 6 with the signals that form the pitch angle stabilization subsystem 7 and 8 in autopilot 1. In the event that the signal from the EMF 4 becomes greater than the value that the subsystem 7 forms to stabilize the maximum allowable pitch angle, control is transferred to this autopilot subsystem 1. A similar, in effect, occurs if the signal from the EMF 4 becomes less than the value that the subsystem forms 8 to stabilize the minimum allowable pitch angle. In this case, the output of the selector 6 is switched with the subsystem 8 of the autopilot 1.

Thus, the signal selector 6 does not allow the pilot under any circumstances to bring the aircraft by erroneous actions to a dangerous mode of operation. The inclusion in the semi-automatic system to prevent the pitch angle of the aircraft outside the operating range of the switch 9, controlled by the signal from the comparison unit 10, provides control to the autopilot 1 only when the flight altitude of the aircraft becomes less than a certain threshold value determined by the setpoint 11. In contrast to the system ( 2), in which the autopilot of the given pitch angle is excluded from the selector control loop, in the present invention, the pilot is excluded from the control.

Obtained by mathematical modeling examples (Fig.2-11), illustrating the operation of a semi-automatic system to prevent the pitch angle beyond the operational range, confirm the effectiveness of the proposed system. Mathematical modeling of flight dynamics was carried out on the model of one of the existing aircraft. In the conducted numerical experiments, the reaction of the aircraft to a series of summer residences of the "from myself - to myself" control stick was checked (see Fig. 2 and Fig. 7) with the signal selector on and off. The graphs in Fig.2-6 and Fig.7-11 differ from each other in amplitude and frequency of the control action in the form of RU cottages. As can be seen from the comparison of the graphs of the pitch angle change (Figs. 3–4 and Figs. 8–9) with the signal selector turned on, the pitch angle slightly exceeds the specified maximum angle of 12 °, and also turns out to be slightly less than the specified minimum angle of 5 °.

It is assumed that the introduction of a semi-automatic system to prevent the aircraft's pitch angle beyond the operational range will significantly increase the level of landing safety and level the influence of the “human factor” at this stage of the flight.

Information sources

1. Rudis V.I. Semi-automatic aircraft control. - M.: Mechanical Engineering, 1987, p. 122.

2. Patent for the invention, “A system for automatically controlling the pitch angle and limiting the angle of attack of an aircraft” No. 2434785 dated 03/02/2010, IPC В64С 13/18.

3. Patent for utility model “System for automatic removal of an aircraft from the maximum allowable angle of attack” No. 79193 dated September 5, 2008, IPC G05D 1/00.

Claims (1)

A semi-automatic system for preventing the aircraft’s pitch angle beyond the operating range, comprising an autopilot, an elevator drive connected in series to a control handle and an electric remote control system, the input of which, like the autopilot input, is connected to aircraft motion parameters sensors, characterized in that it additionally included a signal selector, a switch, a comparison unit and a setpoint for the height of the inclusion of the signal selector, while the first input of the signal selector is connected to the output of the remote control system, the second and third inputs are respectively connected to the outputs of the stabilization subsystems of the maximum and minimum pitch angles of the autopilot, and the output of the signal selector is connected via a switch to the elevator drive, the other input of the switch is connected to the remote control system, and the third, the control input of the switch , connected to the output of the comparison unit, the first input of which is connected to the output of the setpoint of the height of the inclusion of the signal selector, and the second input The od is connected to the output of the aircraft motion parameters sensors.

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