Parachute opening control method for reducing breakage probability of escape parachute

Abstract

The invention belongs to the technical field of aviation lifesaving, and provides a parachute opening control method for reducing the breakage probability of a lifesaving parachute, which comprises the following steps of: determining a coordinate system of a person-chair system; when seat ejection is started, current speed, sky velocity, height, attitude and attitude angular velocity parameters are inquired in real time, and after a secondary power main rocket flames out, roll angular velocity and pitch angular velocity are controlled by percussion of an attitude rocket, so that parachute ejection in a high angular velocity state is avoided; when the current speed and the height are both smaller than or equal to the preset values, whether the sky-direction speed is smaller than 0 is judged; if the sky-direction speed is smaller than 0, separating parachute shooting is completed; otherwise, continuing to wait for the sky direction speed to be less than 0. The problem that a parachute canopy is damaged due to the rope sail phenomenon caused by torsion of a parachute rope due to rotation of a parachute box during parachute ejection in an existing reverse pulling method is solved, and the probability of lifesaving failure is reduced.

Description

A method for controlling the deployment of a life-saving parachute to reduce the probability of breakage. Technical Field

[0001] This invention belongs to the field of aviation life-saving technology and relates to a parachute control method using a man-chair system with a pull-back parachute. Background Technology

[0002] To increase the deployment speed, some rocket ejection seats currently designed generally use the inverted pull method for parachute deployment. The inverted pull method requires the seat to control the parachute attitude angle and attitude angular velocity, as well as the parachute speed, in order to avoid the parachute breaking and causing the rescue to fail.

[0003] To accommodate occupants of varying weights and heights, rocket ejection seats feature an adjustable seat basin. The center of gravity of the human-seat-parachute system differs depending on the occupant. Currently, the thrust axis of the rocket engine's second-stage propulsion system is fixed, resulting in a degree of eccentricity for all second-stage propulsion systems. This eccentricity varies for different occupants, causing angular motion within the human-seat-parachute system after ejection under the influence of the second-stage propulsion, with significant differences in magnitude for different occupants. Therefore, the distance between the rocket engine thrust line and the projection of the center of gravity in the XOY plane of the human-seat-parachute system is defined as the eccentricity. Currently, the simulated eccentricity range for rocket ejection seats, based on the occupant's center of gravity distribution, is [17mm, 56mm]. Within this range, the main rocket influences the seat's pitch attitude, facilitating parachute deployment and inflation. However, the large eccentricity range means that aerodynamic forces at different speeds can cause the seat to rotate. Therefore, when the seat and parachute separate, the rope and sail phenomenon is likely to occur, causing the edge of the canopy to inflate before the bottom, resulting in damage to the edge of the canopy.

[0004] Analysis of multiple high, medium, and low-speed combined ejection tests revealed that parachutes are more susceptible to the effects of airflow, chair rotation, and parachute box rotation at medium and high speeds, leading to rope-sail phenomena. Controlling the parachute's attitude angular velocity and orientation at launch, ensuring the launch direction is opposite to the oncoming airflow, can effectively increase the parachute's opening speed and reduce the probability of breakage. Summary of the Invention

[0005] This invention addresses the technical problem that the parachute box rotation during the inverted-pull method of parachute deployment causes the parachute lines to twist, resulting in a rope-sail phenomenon and thus damage to the parachute canopy. It provides a parachute deployment control method to reduce the probability of parachute damage, thereby reducing the probability of parachute damage under the inverted-pull parachute deployment structure.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: a parachute deployment control method to reduce the probability of parachute breakage, comprising the following steps: defining the coordinate system of the human-chair system; determining the weight, center of gravity, eccentricity, and moment of inertia of the seat during ejection, and evaluating the installation positions of the pitch and roll attitude rockets using the aforementioned parameters of the seat, so that the angular velocities generated by the pitch and roll attitude rockets meet the requirements; when the seat ejection is initiated, querying the current speed, azimuth velocity, altitude, attitude angle, and attitude angular velocity parameters in real time; after the main rocket of the second stage power is shut down, controlling the roll and pitch angular velocities by firing the attitude rockets to avoid launching the parachute at a large angular velocity; when the current speed and altitude are both less than or equal to preset values, determining whether the azimuth velocity is less than 0; if the azimuth velocity is less than 0, completing the parachute separation and deployment; otherwise, continuing to wait for the azimuth velocity to be less than 0.

[0007] As a further technical solution of the present invention: the coordinate system of the human-chair system is defined, specifically: the coordinate system of the human-chair system is defined as OXYZ, the origin O is located at the centroid of the human-chair system, the OX axis points to the heading of the aircraft, the OY axis points to the sky in the longitudinal symmetry plane of the human-chair system, and the OZ axis points to the right of the heading direction of the human-chair system according to the right-hand rule.

[0008] As a further technical solution of the present invention: the attitude angle is pitch angle θ and roll angle γ; the attitude angular velocity is pitch angular velocity ωz and roll angular velocity ωx.

[0009] As a further technical solution of the present invention: analyze the human-chair system and evaluate the current weight, center of gravity, moment of inertia and eccentricity of the chair.

[0010] As a further technical solution of the present invention: based on the current weight, center of gravity, moment of inertia and eccentricity of the seat, the installation positions of the two roll attitude rockets and the two pitch attitude rockets are determined, so that the two roll attitude rockets can enable the seat to generate a roll angular velocity of more than 400° / s, and the two pitch attitude rockets can enable the seat to generate a pitch angular velocity of more than 350° / s; thereby meeting the requirements of seat attitude correction and angular velocity suppression.

[0011] As a further technical solution of the present invention: before the seat ejection is activated, based on the test data of the current occurrence of parachute damage, the angular velocity data of the test in which the parachute box rotated and the parachute rope twisted was confirmed, and the threshold value that is prone to rope sail phenomenon was determined.

[0012] As a further technical solution of the present invention: after the seat rocket engine is shut down, it is determined in real time whether the current roll angular velocity ωx and pitch angular velocity ωz are greater than the threshold value that is prone to the rope sail phenomenon. When the angular velocity is greater than the threshold value, the attitude rocket is fired to reduce the angular velocity of the seat.

[0013] As a further technical solution of the present invention: when the pitch angular velocity ωz is any value between -250° to -100° and 150° to 250° during the ejection rescue process, and the roll angular velocity ωx is any value between -400° to -150° and 150° to 400°, and the main rocket is shut down and the axial velocity Vy > 0, the attitude rocket ignition can be determined according to the situation to reduce the probability of parachute breakage.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. In order to reduce the probability of the life-saving parachute breaking, the present invention improves the overall life-saving performance of the rocket ejection seat and reduces the probability of life-saving failure.

[0015] 2. This invention provides a new method for determining the real-time roll rate, pitch rate, and azimuth rate before the rocket ejection seat separates from the parachute, thereby reducing the angular velocity and speed at the moment of parachute separation, lowering the probability of parachute breakage, and thus improving lifesaving performance. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 is a schematic diagram of the installation of the roll and pitch attitude rocket of the present invention on the seat. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0020] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing and simplifying the invention, and should not be construed as limiting the invention. Furthermore, the use of ordinal numbers (e.g., "first and second," etc.) is for distinguishing objects and is not limited to this order, and should not be construed as indicating or implying relative importance.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly, encompassing both direct connection and indirect connection via an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0022] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0024] Example 1: This embodiment of the invention discloses a parachute deployment control method to reduce the probability of parachute breakage, which includes the following steps: defining the coordinate system of the human-chair system; determining the weight, center of gravity, eccentricity, and moment of inertia of the seat during ejection, and evaluating the installation positions of the pitch and roll attitude rockets using the above parameters of the seat to ensure that the angular velocities generated by the pitch and roll attitude rockets meet the requirements; when the seat ejection is initiated, querying the current speed, azimuth velocity, altitude, attitude angle, and attitude angular velocity parameters in real time; after the main rocket of the second stage power is shut down, controlling the roll and pitch angular velocities by firing the attitude rockets to avoid launching the parachute at a large angular velocity; when the current speed and altitude are both less than or equal to preset values, determining whether the azimuth velocity is less than 0; if the azimuth velocity is less than 0, completing the parachute separation and deployment; otherwise, continuing to wait for the azimuth velocity to be less than 0.

[0025] Furthermore, the coordinate system of the human-chair system is defined as follows: the coordinate system of the human-chair system is defined as OXYZ, the origin O is located at the centroid of the human-chair system, the OX axis points to the heading of the aircraft, the OY axis points to the sky in the longitudinal symmetry plane of the human-chair system, and the OZ axis points to the right of the heading direction of the human-chair system according to the right-hand rule.

[0026] Furthermore, the attitude angles are pitch angle θ and roll angle γ; the attitude angular velocities are pitch angular velocity ωz and roll angular velocity ωx.

[0027] Furthermore, the human-chair system is analyzed to assess the current seat's weight, center of gravity, moment of inertia, and eccentricity.

[0028] Furthermore, based on the current weight, center of gravity, moment of inertia, and eccentricity of the seat, the installation positions of the two roll attitude rockets and the two pitch attitude rockets are determined, so that the two roll attitude rockets can enable the seat to generate a roll angular velocity of over 400° / s, and the two pitch attitude rockets can enable the seat to generate a pitch angular velocity of over 350° / s; thus meeting the requirements for attitude correction and angular velocity suppression of the seat.

[0029] Furthermore, before the seat ejection is activated, based on the test data of the current occurrence of parachute damage, the angular velocity data of the test confirmed that the parachute box rotated, causing the parachute ropes to twist, and the threshold value that is prone to rope-sail phenomenon was determined.

[0030] Furthermore, after the seat rocket engine shuts down, it is determined in real time whether the current roll angular velocity ωx and pitch angular velocity ωz are greater than the threshold value that is prone to rope sail phenomenon. When the angular velocity is greater than the threshold value, the attitude rocket is fired to reduce the angular velocity of the seat.

[0031] Furthermore, during ejection rescue, when the pitch velocity ωz is any value between -250° to -100° and 150° to 250°, and the roll velocity ωx is any value between -400° to -150° and 150° to 400°, and the main rocket is shut down while the azimuth velocity Vy is greater than 0, the attitude rocket can be ignited based on the situation to reduce the probability of parachute damage.

[0032] Example 2 of this invention discloses a parachute deployment control method to reduce the probability of parachute breakage. This involves a seat equipped with an embedded control strategy controller and a positive secondary thrust line, capable of real-time sensing or calculation of the three-dimensional (X, Y, Z) attitude angles, three-dimensional (X, Y, Z) angular velocities, velocity V, and altitude H of the human-seat system. It also features multiple attitude control capabilities and a pull-back parachute deployment method. The system is equipped with two roll attitude rockets and two pitch attitude rockets. The above-mentioned parachute deployment control method based on the pull-back method with attitude control capabilities is as follows: Step 1: Define the coordinate system (OXYZ) of the human-seat system. The origin O is located at the centroid of the human-seat system. The OX axis points towards the aircraft's heading, the OY axis points towards the sky within the longitudinal symmetry plane of the human-seat system, and the OZ axis points to the right of the heading direction of the human-seat system according to the right-hand rule. Attitude angles are generally expressed as yaw angle ψ, pitch angle θ, and roll angle γ, while attitude angular velocities are generally expressed as yaw angular velocity ωy, pitch angular velocity ωz, and roll angular velocity ωx.

[0033] Step 2: Analyze the system to evaluate the current weight, center of gravity, moment of inertia, and eccentricity of the seat.

[0034] Step 3: Evaluate the power configuration of the two roll attitude rockets and two pitch attitude rockets in the current seat coordinate system to confirm that the roll angular velocity and pitch angular velocity of the products can meet the requirements of attitude correction and angular velocity suppression.

[0035] Step 4: Based on the test data of the current lifeline breakage, and the angular velocity data of the test that confirmed the parachute box rotation and caused the parachute rope to twist, determine the threshold value that is prone to rope-sail phenomenon, as shown in Table 1.

[0036] Step 5: During ejection seat activation, the controller continuously queries the current velocity V, azimuth velocity Vy, altitude H, attitude (pitch angle θ, roll angle γ), and attitude angular velocity (pitch angular velocity ωz, roll angular velocity ωx). After ejection, different attitude rocket ignition strategies are used to control the attitude angle and attitude angular velocity.

[0037] Step Six: After the seat rocket engine of the second stage power is shut down, determine in real time whether the current roll angular velocity ωx and pitch angular velocity ωz are greater than the threshold value that is prone to rope sail phenomenon. When the angular velocity is greater than the threshold value, fire the attitude rocket to reduce the angular velocity of the seat.

[0038] Step 7: The seat decelerates steadily until the current speed V ≤ V 预设 and H≤H 预设 At that time, the delay is made in real time according to the current celestial velocity Vy, and the separation of the parachute is completed after the celestial velocity Vy is less than 0; otherwise, continue to step six.

[0039] Based on real-time angular velocity and azimuth velocity, roll and pitch attitude rockets are fired to reduce the angular velocity at the moment of parachute deployment. The deployment is delayed based on the azimuth velocity Vy, thereby reducing the probability of parachute breakage. During ejection, when the pitch angular velocity ωz is any value between -250° and -100° and 150° and 250°, and the roll angular velocity ωx is any value between -400° and -150° and 150° and 400°, and the azimuth velocity Vy > 0 after the main rocket extinguishes, the attitude rockets can be ignited as needed to reduce the probability of parachute breakage and ensure rescue safety.

[0040] It uses real-time judgment of roll and pitch angular velocities after the ejection seat's secondary power is shut down, and combines this with azimuth velocity to control the attitude and speed of the rocket ejection seat at the moment of parachute separation. This reduces the tumbling and aerodynamic forces during the parachute inflation process after the parachute is launched, thereby reducing the probability of rope sail phenomena or partial parachute inflation, and thus reducing the probability of parachute breakage.

[0041] A parachute deployment control method to reduce the probability of parachute breakage involves a rocket ejection seat equipped with a chair-mounted inertial navigation system, two pitch pulse rockets, and two roll pulse rockets. Taking the X-type rocket ejection seat as an example, in a two-seat ejection scenario with a heading speed of 250 km / h, a pitch angle of 0°, and a roll angle of 60°, without this invention, the parachute broke during testing. With this invention, no parachute breakage occurred under the same conditions. Therefore, this invention can reduce the probability of parachute breakage.

[0042] Table 1 shows the statistics of roll, pitch, and yaw angular velocities at various characteristic points during the experiment.

[0043] Thus, the objective of this invention has been achieved.

[0044] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A method for controlling the deployment of a life-saving parachute to reduce the probability of breakage, characterized in that, Includes the following steps: Define the coordinate system of the human-chair system; determine the weight, center of gravity, eccentricity, and moment of inertia of the seat during ejection, and use these parameters to evaluate the installation positions of the pitch and roll attitude rockets to ensure that the angular velocities generated by the pitch and roll attitude rockets meet the requirements; when the seat ejection is initiated, query the current speed, azimuth velocity, altitude, attitude angle, and attitude angular velocity parameters in real time; after the main rocket of the second stage power is shut down, control the roll and pitch angular velocities by firing the attitude rockets to avoid parachute deployment at high angular velocities; when the current speed and altitude are both less than or equal to preset values, determine whether the azimuth velocity is less than 0; if the azimuth velocity is less than 0, complete the parachute separation and deployment; otherwise, continue to wait for the azimuth velocity to become less than 0.

2. The parachute deployment control method for reducing the probability of parachute breakage according to claim 1, characterized in that, Define the coordinate system of the human-chair system as follows: Define the coordinate system of the human-chair system as OXYZ, with the origin O located at the centroid of the human-chair system, the OX axis pointing towards the aircraft heading, the OY axis pointing towards the sky within the longitudinal symmetry plane of the human-chair system, and the OZ axis pointing to the right of the heading direction of the human-chair system according to the right-hand rule.

3. The parachute deployment control method for reducing the probability of parachute breakage according to claim 1, characterized in that, The attitude angles are pitch angle θ and roll angle γ; the attitude angular velocities are pitch angular velocity ωz and roll angular velocity ωx.

4. The parachute deployment control method for reducing the probability of parachute breakage according to claim 1, characterized in that, Analyze the human-chair system to assess the current seat's weight, center of gravity, moment of inertia, and eccentricity.

5. The parachute deployment control method for reducing the probability of parachute breakage according to claim 4, characterized in that, Based on the current weight, center of gravity, moment of inertia, and eccentricity of the seat, the installation positions of two roll attitude rockets and two pitch attitude rockets are determined. This ensures that the two roll attitude rockets can generate a roll angular velocity of over 400° / s for the seat, and the two pitch attitude rockets can generate a pitch angular velocity of over 350° / s for the seat, thus meeting the requirements for attitude correction and angular velocity suppression of the seat.

6. The parachute deployment control method for reducing the probability of parachute breakage according to claim 1, characterized in that, Before the ejection seat is activated, based on the test data of the current cases of parachute damage, the angular velocity data of the test in which the parachute box rotated and caused the parachute rope to twist was confirmed, and the threshold value that is prone to rope sail phenomenon was determined.

7. The parachute deployment control method for reducing the probability of parachute breakage according to claim 6, characterized in that, After the seat rocket engine shuts down, it continuously checks whether the current roll velocity ωx and pitch velocity ωz are greater than the threshold value that is prone to rope sail phenomenon. When the angular velocity is greater than the threshold value, the attitude rocket is fired to reduce the angular velocity of the seat.

8. The parachute deployment control method for reducing the probability of parachute breakage according to claim 1, characterized in that, During ejection rescue, when the pitch velocity ωz is any value between -250° to -100° and 150° to 250°, and the roll velocity ωx is any value between -400° to -150° and 150° to 400°, and the main rocket is shut down while the azimuth velocity Vy is greater than 0, the attitude rocket can be ignited based on the situation to reduce the probability of parachute breakage.

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