RU2280592C1 - Method of generation of ejection seat parachute deployment command - Google Patents

Abstract

FIELD: aeronautical engineering; control of ejection seats; generation of commands for control of ejection seat and emergency parachute for escape of pilot in an emergency.

SUBSTANCE: in case there is no communication with aircraft board, command for parachute deployment shall be generated not by time but by the data on braking overload obtained from overload sensor mounted on ejection seat. According to one version, parachute deployment command is generated on basis of comparison of real braking overload with one of six permissible magnitudes which depend on altitude determined with the aid of two baro-relays adjusted to altitude of 2 and 6 km and on sub-range of pilot mass wearing the outfit set before flight by means of three-position toggle switch fitted on ejection seat. According to another version, parachute deployment command is generated on basis of analysis of change in braking overload at some time intervals and analytical determination of speed of motion of ejection seat. When this speed is lesser than or is equal to permissible rate of parachute deployment, command is sent for deployment at time lag which is multiple of time interval of determination of seat speed of motion.

EFFECT: reduced minimum safe ejection altitude at absence of information signals from aircraft board.

3 cl, 1 dwg, 1 tbl

Description

The invention relates to aircraft, in particular, to rescue aircraft crew.

A known method of controlling the operating mode of the ejection seat K-36D-3,5 (see. Manual for technical operation 903-9200-1000.0-02RE-LU, Edition of JSC "Research Institute of Stars" 1999, and application No. 97112580/28 (013156) dated July 22, 1997), in which the information received from the aircraft about the speed and height of flight, the vertical speed of descent, vertical overload, the angle and angular velocity of the roll and the fact that the landing gear was crimped at the moment of ejection is used to change the functional configuration of the seat. In this case, the command to enter the pilot's rescue parachute is generated using on-board data about the flight mode and ejection acceleration braking sensors placed on the seat.

In the absence of power supply or failure on board for various reasons, information systems of the aircraft, a strictly defined functional diagram of the seat is implemented. In this case, the command to enter the pilot's rescue parachute is generated after a strictly defined time using the electronic timer, which starts when the chair is separated from the aircraft. This time ensures that the seat is braked to the permissible speed and, accordingly, safe parachute entry with the most unfavorable combination of parameters - the maximum possible pilot weight, the maximum flight altitude allowed for the parachute to enter, the “hot” atmosphere, the maximum possible aircraft flight speed and the dive angle of the aircraft minus 90 °. If the actual flight conditions, the state of the atmosphere and the mass characteristics of the pilot differ from the limit values, then the introduction of the parachute in these cases is carried out with excessive delay. Because of this, the minimum safe bailout height unnecessarily increases.

The closest technical solution to the problem of developing a command for launching a parachute in the absence of information from the board about the flight mode of the aircraft and the presence of acceleration sensors on the seat is a way to use the seat braking overload value n. The overload of braking the chair at a time when the speed becomes acceptable for the input of the rescue parachute [V] _nc is determined by the ratio:

where C _x S is the drag coefficient of the chair;

ρ is the density of the atmosphere;

m is the mass of the ejection seat with the pilot;

g is the acceleration of gravity.

The same speed of the ejection seat, permissible to enter the parachute [V] _p. , but different masses of the pilot, height of ejection and the state of the atmosphere, which determine the density of the atmosphere ρ, aerodynamic drag coefficient C _x S, which depends on the anthropometric dimensions of the pilot in equipment, correspond to different values of braking overload, which differ by more than 2 times.

Therefore, if as the determining value of the braking overload at the moment of launching the parachute, we select the value realized at the maximum ejection mass, at the maximum height allowed for launching the parachute, in the conditions of a “hot” atmosphere, then in other conditions, in particular, at low mass, at ejection near the ground in a "cold" atmosphere, the speed of the ejection seat at the time this value of overload is realized will be significantly less than the permissible [V] _pc. , the parachute will be introduced with excessive delay, because of which for this case the value of the minimum safe height will be unreasonably overestimated.

That is why the method of developing a control command for the introduction of a rescue parachute in the absence of information connection with the board directly from the overload determined for the extreme values of the determining parameters - the maximum ejection mass, the maximum allowed height for the introduction of the parachute and the "hot" atmosphere, differs little from the method with a constant delayed.

An object of the invention is in the absence of information signals from the aircraft about the flight modes of the aircraft, as well as in the atmosphere and mass characteristics of the pilot, other than the limit, ensuring a decrease in the minimum safe height of the ejection using acceleration sensors located in the ejection seat and measuring its overload time braking.

For this, it is proposed to use two mutually duplicating methods for generating a control for the introduction of a parachute:

1. The magnitude of the overload braking, the permissible value of which [n] is set

- depending on the height of the bailout, determined using two barorelles, which are tuned to a height of H = 2 km and H = 6 km;

- depending on the ejection mass, the subrange of which is set on the ejection seat using a three-position toggle switch (subbands of small, medium and large mass - PM, PS and PB, respectively).

Therefore, the measured values of the overload n can be compared with the six acceptable values [n] set in accordance with table 1.

Table 1 Bailout height Values [n] Mass subrange PM PS PB N≤ 2km [n] _2m [n] _2c [n] _2B 2 km <N≤6 km [n] _6m [n] _6c [n] _6B

And with

a command is issued to enter the parachute.

2. According to the value of the speed of the spacecraft, determined on the basis of information obtained using the overload sensor on the magnitude of the braking overload and the change in this overload in time, while no other information is used.

The change in speed V of the ejection seat in time τ at V> [V] _p.c. after the rocket engine of the chair is finished, it is described with a sufficient degree of accuracy by the following differential equation:

where m is the total ejection mass;

C _x S - aerodynamic drag coefficient;

ρ is the density of the atmosphere.

The parameters C _x S, ρ and m are indefinite, while the parameter m is constant but unknown, and the parameters C _x S and ρ are time-varying and also unknown. However, for a short time of the order of T = 0.1-0.15 s, the parameters C _x S and ρ can also be considered constant, although unknown.

Then the solution of the specified differential equation has the form:

where V _o - the initial speed of the chair;

V is the current speed of the chair;

n _o - overload braking chairs at the initial moment of the considered time interval.

On the other hand, the value of V can be determined as follows:

where n is the current measured value of the overload braking of the chair. Substituting (5) in (4), we finally obtain:

Analyzing during the movement of the ejection seat in free flight the change in the measured value of the braking overload on a consecutive series of time intervals T, using the relation (6), the speed of the seat is determined at the initial moment of each time interval. And in the case when this speed is less than or equal to [V] _p.c. , is generated with a time delay equal to T, a command to enter the rescue parachute.

The proposed method can be implemented as follows.

In an emergency, after the ejection command is received, the ejection seat automation system is turned on and control commands for the operation of the ejection systems are generated. In this case, the command to enter the rescue parachute is generated on two independent lines - on the main line using on-board information about the airplane’s flight mode and information from the seat acceleration sensors and on two mutually duplicating lines using data only from the seat acceleration sensors in accordance with the relations (2 ) and (6).

In the absence of information from the board about the aircraft’s flight mode at the moment of bailout, only duplicate commands are generated.

This method is implemented by the known design of the ejection seat, comprising a seat, a headrest with stabilizing rods and a rescue parachute placed in it, an automatic seat control system and an autonomous power source, in the automatic control system of which an additional barrelera adjusted to a height of 2 km is added, and a three-position toggle switch , with the help of which the mass of the pilot in the equipment is set on the QC, it is connected with an electronic QC calculator that implements the control algorithm described above -governing teams to enter the chute.

An example of the method in the following bailout mode:

aircraft speed V _o = 1244 km / h

(indicator speed V _i = 1100 km / h);

barometric height H = 1.5 km;

the atmosphere is hot;

pilot mass corresponds to a sub-range of average masses.

The drawing shows the calculated change in the load of the chair’s braking load n in time, the moments of the development of the command to enter the rescue parachute along the main line (time τ ₁ ), as well as the moments of the generation of control commands that would be realized using a constant time delay τ ₄ and the proposed method using the permissible overload value (time instant τ ₃ ) and determining the speed of the spacecraft (time point ₂ ), τ = 0 corresponds to the moment of separation of the spacecraft from the aircraft.

Claims (2)

1. The method of generating a command to enter the parachute of the ejection seat (QC) in the absence of information connection of the ejection seat with the side, which consists in measuring the overload of braking of the spacecraft in time and the subsequent submission of a duplicated command to enter the rescue parachute, characterized in that the measured value of the load of braking of the spacecraft n compared with one of six possible allowable values [n], which depend on the height at which the bailout occurred, determined using two barorelles, tuned to a height of 2 and 6 to And by mass pilot subband in the equipment defined by the flight in front of the pilot subbands in the form of small, medium and large masses via the three-position toggle switch, mounted on the spacecraft, and when the condition n <[n] produce a command to enter emergency parachute. 2. The method of generating a command to enter the parachute of the ejection seat (QC) in the absence of information connection between the spacecraft and the side, which consists in measuring the overload of the spacecraft's braking in time and then issuing a duplicated command to enter the rescue parachute, characterized in that it changes over a number of time intervals the current value of the measured CC brake inhibition over time determines the speed V ₀ of the CC movement at the initial moment of each time interval T according to the expression

where n ₀ is the value of the overload at the beginning of each time interval, g is the acceleration of gravity, and in the case when the speed V _{0 is} less than or equal to the allowable input speed of the rescue parachute, a command is issued to enter it with a time delay that is a multiple of the time interval for determining the speed of the chair, and the value T of the time interval is set to 0.1-0.15 s.