Aircraft water-touching judgment method based on angular velocity information

Abstract

The present invention provides a method for judging an aircraft touching water based on angular velocity information, the method comprising: measuring the pitch angular velocity ω of the aircraft in real time z ; Filter the pitch angular velocity to obtain a filtered pitch angular velocity; and determine whether the aircraft has touched water based on the filtered pitch angular velocity and a set water-touching threshold. This technical solution can accurately determine the water-touching state of the aircraft, and the method has high reliability, simple design, and is easy to implement.

Description

Technical Field

[0001] The invention belongs to the field of aircraft control and relates to an aircraft water contact judgment method based on angular velocity information. Background Art

[0002] With the rapid development of aircraft technology, its movement space has also developed from the traditional single atmospheric intermediary space to the space across water-air medium. In the process of aircraft crossing water-air medium, it is subject to complex air / water dynamic coupling forces, and an accurate and reliable water contact judgment method is urgently needed to judge the intermediary environment and force state of the aircraft, so as to achieve stable control of the aircraft's attitude and trajectory. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0004] To this end, the present invention provides a method for determining whether an aircraft has touched water based on angular velocity information. The method of the present invention is suitable for determining the water-touching state of an aircraft when it is passing through a water-air medium, and switching control strategies accordingly.

[0005] The technical solution of the present invention is as follows:

[0006] According to one aspect, a method for determining whether an aircraft has touched water based on angular velocity information is provided, the method comprising:

[0007] Real-time measurement of the pitch angular velocity ω of the aircraft z ;

[0008] Performing filtering on the pitch angular velocity to obtain a filtered pitch angular velocity;

[0009] Whether water contact occurs is determined based on the filtered pitch angular velocity and a set water contact threshold.

[0010] Furthermore, the onboard inertial navigation system is used to measure the pitch angular velocity ω of the aircraft in real time. z .

[0011] Furthermore, the pitch angular velocity is filtered by the following formula to obtain a filtered pitch angular velocity:

[0012]

[0013] in,

[0014] T is the filtering time constant;

[0015] step is the sampling period;

[0016] y(k) is the pitch angular velocity after filtering;

[0017] x(k) is the pitch angular velocity before filtering;

[0018] y(k-1) is the pitch angular velocity after filtering in the previous cycle;

[0019] x(k-1) is the pitch angular velocity before filtering in the previous cycle.

[0020] Furthermore, the angular velocity update period of the inertial navigation output is equal to the angular velocity filtering period.

[0021] Furthermore, when filtering the pitch angular velocity, x(k-1) is initialized to the pitch angular velocity of the aircraft body coordinate system output by the integrated navigation system at the current moment, and y(k-1)=x(k-1).

[0022] Furthermore, the water contact threshold is designed in the following manner:

[0023] The maximum absolute value of the pitch velocity within 1 second after the aircraft completes the maneuver and descends, plus 50° / s.

[0024] Further, determining whether water contact has occurred according to the filtered pitch angular velocity and a set water contact threshold comprises:

[0025] If the absolute value of the pitch angular velocity after filtering exceeds the water contact threshold value for two consecutive times, water contact is determined.

[0026] According to another aspect, a computer device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned determination method when executing the computer program.

[0027] The above technical solution proposes for the first time a method for judging water contact based on the pitch angular velocity of an aircraft. The existing aircraft inertial navigation equipment can be used to judge the water contact status of the aircraft by utilizing the pitch angular velocity of the aircraft output by the inertial navigation, through corresponding filtering algorithms and judgment principles. This method has high reliability, simple design and is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The included drawings are used to provide a further understanding of the embodiments of the present invention, which constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the text description, explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 The pitch angular velocity and height change process of the aircraft during water contact provided by the embodiment of the present invention;

[0030] Figure 2 is a pitch angular velocity curve of an aircraft body coordinate system during water contact provided by an embodiment of the present invention;

[0031] Figure 3 The invention provides an aircraft water touchdown process judgment based on a water touchdown threshold. DETAILED DESCRIPTION

[0032] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0034] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0035] like Figure 1 As shown, in one embodiment of the present invention, a method for determining that an aircraft has touched water based on angular velocity information is provided, the method comprising:

[0036] Step 1: Real-time measurement of the pitch angular velocity ω of the aircraft z ;

[0037] Step 2: filtering the pitch angular velocity to obtain a filtered pitch angular velocity;

[0038] Step 3: Determine whether water contact occurs based on the filtered pitch angular velocity and a set water contact threshold.

[0039] For example, the onboard inertial navigation system can be used to measure the pitch angular velocity ω of the aircraft in real time. z .

[0040] It can be seen that the water-touching judgment method based on pitch angular velocity in the embodiment of the present invention is to judge the water-touching process of the aircraft by judging the pitch angular velocity of the aircraft. The main strategy is to use the pitch angular velocity measured in real time by the inertial navigation system on the aircraft, and then obtain the filtered pitch angular velocity through the relevant algorithm for water-touching judgment.

[0041] That is, the embodiment of the present invention proposes for the first time a method for judging water contact based on the pitch angular velocity of an aircraft. The method can utilize the existing inertial navigation equipment on the aircraft, and judge the water contact state of the aircraft by utilizing the pitch angular velocity of the aircraft output by the inertial navigation, through corresponding filtering algorithms and judgment principles. The method has high reliability, simple design, and is easy to implement.

[0042] In the above embodiment, in order to ensure accurate judgment of water contact, the pitch angular velocity is filtered by the following formula to obtain the filtered pitch angular velocity:

[0043]

[0044] in,

[0045] T is the filtering time constant;

[0046] step is the sampling period;

[0047] y(k) is the pitch angular velocity after filtering;

[0048] x(k) is the pitch angular velocity before filtering;

[0049] y(k-1) is the pitch angular velocity after filtering in the previous cycle;

[0050] x(k-1) is the pitch angular velocity before filtering in the previous cycle.

[0051] That is, due to the complex air / water dynamic interference during the water contact of the aircraft, the pitch angular velocity obtained in step 1 cannot be directly used for water contact judgment. The embodiment of the present invention performs filtering processing and designs a pitch angular velocity wave algorithm as follows:

[0052] Design a first-order inertial link filter F(s) for the pitch angular velocity ωz (i.e., the angular velocity of the z-axis of the aircraft body coordinate system) is filtered, and the transfer function is:

[0053]

[0054] The time constant T is 0.01s.

[0055] Preferably, the angular velocity update period of the inertial navigation output is equal to the angular velocity filtering period. For example, the angular velocity update period of the inertial navigation output is 10 ms, so the angular velocity filtering period step is set to 10 ms.

[0056] Preferably, when filtering the pitch angular velocity, for the first beat of the iteration process, x(k-1) is initialized to the pitch angular velocity of the aircraft body coordinate system output by the integrated navigation system at the current moment, and y(k-1)=x(k-1).

[0057] In the above embodiment, in order to accurately determine the water contact state, the water contact threshold is designed in the following manner:

[0058] The maximum absolute value of the pitch velocity within 1 second after the aircraft completes the maneuver and descent plus 50° / s is used as the water touch judgment threshold

[0059] In the above embodiment, determining whether water contact occurs according to the filtered pitch angular velocity and the set water contact threshold value includes:

[0060] If the absolute value of the filtered pitch angular velocity exceeds the water contact threshold value for a cumulative total of two times, water contact is determined.

[0061] Based on the actual test examples, Figure 1 It is a schematic diagram of the pitch angular velocity and height change process of the aircraft during the water contact process. It can be seen that after the aircraft touches the water, the height is close to the water surface. Before the aircraft touches the water, the pitch angular velocity of the aircraft is very small. During the water contact process, a large mutation and violent oscillation occur. After the aircraft leaves the water, the pitch angular velocity quickly converges to the state before the water contact. The present invention uses the pitch angular velocity ω of the aircraft body coordinate system output by the inertial navigation z , to judge the water-touching status of the aircraft, the biggest advantage of this method is its high reliability, simple design and easy implementation.

[0062] Figure 2 The pitch angular velocity ω of the vehicle body coordinate system before filtering during water contact is given in z and the filtered ω z After touching the water, the original pitch angular velocity output by the inertial navigation is very large. After filtering, the pitch angular velocity change amplitude used for water touchdown judgment is smaller than the original angular velocity information. That is, the pitch angular velocity obtained after filtering can ensure the accuracy of the post-water touchdown judgment.

[0063] Figure 3 The figure shows a water touch judgment process based on the filtered pitch angular velocity threshold. The horizontal line represents the set water touch pitch angular velocity judgment threshold, and the dotted line represents the filtered aircraft pitch angular velocity. If the absolute value of the filtered pitch angular velocity exceeds the water touch threshold for two consecutive frames, it is judged that the water touch is taken.

[0064] It can be seen that the embodiment of the present invention proposes and verifies a strategy for judging the aircraft's water-touching state based on pitch angular velocity information, and judges the aircraft's water-touching state by utilizing the pitch angular velocity output by the inertial navigation system in real time; and because the aircraft's water-touching movement involves aero / hydrodynamics, rigid body mechanics, and elastic body mechanics, and is in an extremely complex aero / hydrodynamic environment, under various interference conditions, the pitch angular velocity information calculated after the inertial navigation system collects the information contains relatively large noise. The present invention designs a suitable filtering algorithm to filter the pitch angular velocity information, and the filtered signal obtained is used for water-touching judgment; and the water-touching state can be accurately acquired according to the designed judgment criteria.

[0065] Features described and / or illustrated above for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with or used in place of features in other embodiments.

[0066] It should be emphasized that the term "include / comprises" when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps, components or combinations thereof.

[0067] The above method of the present invention can be implemented by hardware, or by hardware combined with software. The present invention relates to such a computer-readable program, which, when executed by a logic component, enables the logic component to implement the above-mentioned device or component, or enables the logic component to implement the above-mentioned various methods or steps. The present invention also relates to a storage medium for storing the above program, such as a hard disk, a magnetic disk, an optical disk, a DVD, a flash memory, etc.

[0068] The many features and advantages of these embodiments are apparent from this detailed description, and thus the appended claims are intended to cover all such features and advantages of these embodiments that fall within their true spirit and scope. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not intended that the embodiments of the invention be limited to the exact construction and operation illustrated and described, but rather all suitable modifications and equivalents falling within the scope thereof are intended to be covered.

[0069] Parts of the present invention that are not described in detail are well known to those skilled in the art.

Claims

1. A method for determining whether an aircraft has touched water based on angular velocity information, characterized in that: The method comprises: Real-time measurement of the aircraft's pitch velocity ; Performing filtering on the pitch angular velocity to obtain a filtered pitch angular velocity; Determining whether water contact has occurred based on the filtered pitch angular velocity and a set water contact threshold; When filtering the pitch angular velocity, x ( k -1) Initialize the pitch angular velocity of the aircraft body coordinate system output by the integrated navigation system at the current moment, and let y ( k -1)= x ( k -1), where x ( k -1) is the pitch angular velocity before filtering in the previous cycle, y ( k -1) pitch angular velocity after filtering in the previous cycle; The water-touching threshold is designed in the following way: the maximum absolute value of the pitch velocity within 1 second after the aircraft completes the maneuvering descent plus 50° / s; Determining whether water contact occurs according to the filtered pitch angular velocity and a set water contact threshold value includes: If the absolute value of the filtered pitch angular velocity exceeds the water contact threshold value twice in succession, water contact is determined.

2. The method for determining whether an aircraft has touched water based on angular velocity information according to claim 1, characterized in that: Use the onboard inertial navigation system to measure the pitch velocity of the aircraft in real time .

3. A method for determining whether an aircraft has touched water based on angular velocity information according to any one of claims 1 to 2, characterized in that: The pitch angular velocity is filtered by the following formula to obtain the filtered pitch angular velocity: in, is the filtering time constant; is the sampling period; is the pitch angular velocity after filtering; is the pitch angular velocity before filtering; is the pitch angular velocity after filtering in the previous cycle; is the pitch angular velocity before filtering in the previous cycle.

4. The method for determining whether an aircraft has touched water based on angular velocity information according to claim 3, characterized in that: The angular velocity update period of the inertial navigation output is equal to the angular velocity filtering period.

5. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the judgment method according to any one of claims 1 to 4 when executing the computer program.

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