A method for querying oil quantity data

Abstract

The present invention belongs to the field of aircraft fuel quantity measurement, and more specifically, relates to a fuel quantity data query method. The method establishes an intermediate coordinate system O-X 1 Y 1 Z 1 , the earth coordinate system O‑XYZ and the body coordinate system O‑X 2 Y 2 Z 2 , by transforming the roll angle and pitch angle of the aircraft, the conversion between the earth coordinate system and the body coordinate system is realized through the intermediate coordinate system, so as to calculate the attitude angle of the aircraft in different coordinate systems, and at the same time, use the fuel quantity database of a coordinate system to query the corresponding fuel quantity data in the earth coordinate system and the body coordinate system. The present invention realizes fast calculation of the aircraft attitude angle and query of the fuel quantity under the corresponding attitude angle through the above operation.

Description

Technical Field

[0001] The invention belongs to the field of aircraft fuel quantity measurement, and in particular relates to a fuel quantity data query method. Background Art

[0002] Fuel quantity measurement can provide the pilot with accurate information about the amount of fuel in the aircraft tank, and plays an important role in the pilot making correct flight decisions in real time. With the development and progress of science and technology, the requirements for the accuracy, stability and reliability of fuel quantity measurement are getting higher and higher. In order to improve the accuracy of the measurement, the commonly used table lookup to calculate the volume to obtain the fuel quantity is usually an altitude lookup table, an aircraft attitude angle lookup table, and an oil surface angle lookup table calculated based on attitude acceleration. In order to ensure that effective and high-precision fuel quantity information can be obtained in the above-mentioned fuel quantity measurement method, it is necessary to ensure that the aircraft attitude angle substituted into the calculation is a value in the body coordinate system. When the influence of acceleration is ignored, such as Figure 1 As shown, Figure 1 This is a simple process diagram of several methods we generally use to obtain the oil volume through the oil surface angle ( , For the oil level angle), when the given attitude angle is relative to different coordinate systems, we need to call different oil quantity databases, which is troublesome, so we need to convert the oil level angle calculated by the geodetic coordinate system to the body coordinate system to facilitate the oil quantity calculation. Summary of the invention

[0003] The present invention aims at the problem that in the prior art, during the fuel quantity calculation process, the attitude angles of the aircraft in multiple coordinate systems need to be calculated, and multiple fuel quantity databases need to be queried, which is cumbersome to use. A fuel quantity data query method is proposed, by establishing an intermediate coordinate system, and obtaining the coordinate conversion relationship between the body coordinate system and the earth coordinate system by the intermediate coordinate system, so as to achieve the establishment of a coordinate system fuel quantity database, and according to a coordinate attitude angle input, the desired fuel quantity data output can be obtained according to the conversion relationship between the body coordinate system, the earth coordinate system and the intermediate coordinate system.

[0004] The specific implementation contents of the present invention are as follows:

[0005] The present invention proposes a method for querying oil quantity data, and establishes an intermediate coordinate system OX 1 Y 1 Z 1 , Earth coordinate system O-XYZ and body coordinate system OX 2 Y 2 Z 2, by transforming the roll angle and pitch angle of the aircraft, the conversion between the earth coordinate system and the body coordinate system is realized through the intermediate coordinate system, so as to calculate the attitude angle of the aircraft in different coordinate systems, and at the same time use the fuel quantity database of a coordinate system to query the corresponding fuel quantity data in the earth coordinate system and the body coordinate system.

[0006] In order to better implement the present invention, further, the intermediate coordinate system OX 1 Y 1 Z 1 The establishment operation is as follows: first establish the standard geodetic coordinate system O-XYZ, then use the geodetic coordinate system O-XYZ as the reference, raise the aircraft nose up by an angle α, that is, rotate the Y axis of the geodetic coordinate system O-XYZ clockwise by an angle α, and obtain the intermediate coordinate system OX 1 Y 1 Z 1 .

[0007] In order to better implement the present invention, further, the body coordinate system OX 2 Y 2 Z 2 The specific steps of establishing are as follows: In the intermediate coordinate system OX 1 Y 1 Z 1 Based on this, we further use the geodetic coordinate system O-XYZ as the reference and transform the intermediate coordinate system OX 1 Y 1 Z 1 Rotate the X-axis of the earth coordinate system O-XYZ by an angle β to obtain the body coordinate system OX 2 Y 2 Z 2 .

[0008] In order to better implement the present invention, further, the geodetic coordinate system O-XYZ is converted into the intermediate coordinate system OX 1 Y 1 Z 1 After that, the X-axis between the two coordinate systems remains unchanged, X=X 1 , convert to obtain the geodetic coordinate system O-XYZ and the intermediate coordinate system OX 1 Y 1 Z 1 The coordinate transformation relationship between them is:

[0009] (1)

[0010] Transform formula (1) to obtain formula (2):

[0011] (2)

[0012] According to formula (1) and formula (2), we can get the geodetic coordinate system O-XYZ and the intermediate coordinate system OX 1 Y 1 Z 1 The coordinate transformation matrix between:

[0013] (3).

[0014] In order to better implement the present invention, further, the intermediate coordinate system OX 1 Y 1 Z 1 Rotate the X-axis of the earth coordinate system O-XYZ by an angle β to obtain the body coordinate system OX 2 Y 2 Z 2 After that, the intermediate coordinate system OX 1 Y 1 Z 1 With the body coordinate system OX 2 Y 2 Z 2 The Y axis between them remains unchanged, Y 1 =Y2, converted to the intermediate coordinate system OX 1 Y 1 Z 1 With the body coordinate system OX 2 Y 2 Z 2 The coordinate transformation relationship between them is:

[0015] (4)

[0016] Transforming formula (4) into formula (5):

[0017] (5)

[0018] According to formula (4) and formula (5), the intermediate coordinate system OX is obtained 1 Y 1 Z 1 With the body coordinate system OX 2 Y 2 Z 2 The coordinate transformation matrix between:

[0019] (6).

[0020] In order to better implement the present invention, further, the earth coordinate system O-XYZ and the intermediate coordinate system OX are obtained by calculation. 1 Y 1 Z 1 The coordinate transformation relationship between the intermediate coordinate system OX 1 Y1 Z 1 With the body coordinate system OX 2 Y 2 Z 2 After the coordinate conversion relationship between them, the geodetic coordinate system O-XYZ and the intermediate coordinate system OX are converted according to the obtained coordinate conversion relationship. 1 Y 1 Z 1 、Body coordinate system OX 2 Y 2 Z 2 The coordinate conversion relationship between the two coordinates is established to establish a coordinate oil quantity database. According to the coordinate conversion relationship between the two coordinates of the three coordinates, the oil quantity database query is performed. The geodetic coordinate system O-XYZ and the body coordinate system OX 2 Y 2 Z 2 The coordinate transformation relationship is as follows:

[0021] (7)

[0022] (8)

[0023] (9).

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] You only need to establish a fuel quantity database to query the fuel quantity data at different aircraft attitude angles, which is convenient and quick to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a simplified flow chart of the prior art for calculating the fuel quantity by the aircraft attitude angle;

[0027] Figure 2 A flow chart of the present invention for calculating the conversion of the aircraft attitude angle according to the coordinate conversion relationship between different coordinate systems;

[0028] Figure 3 In order to take the body coordinate system as the standard, the earth coordinate system O-XYZ is rotated to obtain the intermediate coordinate system OX 1 Y 1 Z 1 Schematic diagram of the coordinate model;

[0029] Figure 4 In order to take the body coordinate system as the standard, in the intermediate coordinate system OX 1 Y 1 Z 1 Based on the rotation, the body coordinate system OX is obtained 2 Y 2 Z2 Schematic diagram of the coordinate model;

[0030] Figure 5 In order to take the geodetic coordinate system as the standard, the geodetic coordinate system O-XYZ is rotated to obtain the intermediate coordinate system OX 1 Y 1 Z 1 Schematic diagram of the coordinate model;

[0031] Figure 6 In order to take the geodetic coordinate system as the standard, in the intermediate coordinate system OX 1 Y 1 Z 1 Based on the rotation, the body coordinate system OX is obtained 2 Y 2 Z 2 Schematic diagram of the coordinate model;

[0032] Figure 7 Schematic diagram of the aircraft analysis model in three coordinate systems Figure 1 ;

[0033] Figure 8 Schematic diagram of the aircraft analysis model in three coordinate systems Figure 2 ;

[0034] Fig. 9 This is a diagram of any point A in the coordinate system. Figure 1 ;

[0035] Fig.10 This is a diagram of any point A in the coordinate system. Figure 2 . DETAILED DESCRIPTION

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, 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. It should be understood that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, and therefore should not be regarded as limiting the scope of protection. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technical personnel in this field without making creative work are within the scope of protection of the present invention.

[0037] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] Embodiment 1:

[0039] This embodiment proposes a method for querying oil quantity data. Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 As shown, from Figure 1 It can be seen that when the given attitude angle is relative to different coordinate systems, we need to call different oil volume databases, which is troublesome. 1 Y 1 Z 1 , Earth coordinate system O-XYZ and body coordinate system OX 2 Y 2 Z 2 , by transforming the roll angle and pitch angle of the aircraft, the conversion between the earth coordinate system and the body coordinate system is realized through the intermediate coordinate system, so as to calculate the attitude angle of the aircraft in different coordinate systems, and at the same time use the fuel quantity database of a coordinate system to query the corresponding fuel quantity data in the earth coordinate system and the body coordinate system. Figure 5 As shown, first establish a standard geodetic coordinate system O-XYZ, then use the geodetic coordinate system O-XYZ as a reference, raise the nose of the aircraft by an angle α, that is, rotate the Y axis of the geodetic coordinate system O-XYZ clockwise by an angle α, and obtain the intermediate coordinate system OX 1 Y 1 Z 1 The above method takes the view based on the body coordinate system as the reference. Figure 3 As shown. Figure 6 As shown, in the intermediate coordinate system OX 1 Y 1 Z 1 Based on this, we further use the geodetic coordinate system O-XYZ as the reference and transform the intermediate coordinate system OX 1 Y 1 Z 1 Rotate the X-axis of the earth coordinate system O-XYZ by an angle β to obtain the body coordinate system OX 2 Y 2 Z 2 The above operation is based on the body coordinate system. Figure 4 As shown. Figure 2 As shown, the aircraft attitude angle corresponding to the established fuel quantity database can be obtained according to the conversion relationship between the earth coordinate system and the body coordinate system.

[0040] Embodiment 2:

[0041] This embodiment is based on the above embodiment 1, further, as Figure 7 , Figure 8 As shown, the first rotation obtains the intermediate coordinate system OX 1 Y 1 Z 1 When the y-axis position does not change, the y-coordinate value remains unchanged y=y 1 , but the body coordinate system OX 2 Y 2 Z 2 When the second rotation is obtained, the positions of the three axes are changed, so x 1 ,y 1 、z 1 These three coordinate values ​​will change, which is not conducive to calculation. Therefore, if the aircraft is analyzed Figure 7 As shown:

[0042] Observe from the negative direction to the positive direction along the x-axis of the geodetic coordinate system O-XYZ (the plane is flying head-on), and the position relationship between the two coordinate systems is shown in the figure above. It is the projection of the aircraft head position in three positions during rotation. 2 The angle between the wing axis and the Ox axis is α (the pitch angle with the ground as the reference system), and the wing axis Oy 2 The angle between the wing plane and the Oy axis is β (roll angle with the ground as the reference system). Note that the angle between the wing plane and the Oy axis is not β. Because this plane is not parallel to the Ox axis, there is a pitch angle α.

[0043] If we first let the aircraft fuselage axis Ox 2 Return to the Ox axis (coinciding with the Ox axis direction), and then rotate in the opposite direction by an angle of β, the body coordinate system will coincide with the earth coordinate system (returning to the original position), so the rotation order can be changed as follows Figure 8 As shown, the aircraft is first rotated around the Ox axis (fuselage axis) by an angle β (roll angle), and the body coordinate system obtained at this time is recorded as OX a Y a Z a , and then let the plane fly around OY a The same body coordinate system OX can be obtained by rotating the axis (wing axis) by an angle α (pitch angle) 2 Y 2 Z 2 , and the corresponding rotation angle is also the same. This rotation method keeps one axis position unchanged each time, and its corresponding coordinates remain unchanged, which is convenient for calculation.

[0044] The other parts of this embodiment are the same as those of the above-mentioned embodiment 1, and thus will not be described in detail.

[0045] Embodiment 3:

[0046] This embodiment is based on any one of the above embodiments 1-2. Fig. 9 , Fig.10 As shown, set a point A, which represents a point that may be encountered in practice. According to the above, the first rotation is around the Ox axis, so the value of x remains unchanged (x 1 =x), point A is any point in space, Fig. 9 From the geometric relationship, we can know that:

[0047] Right now: ;

[0048] Therefore, the first coordinate transformation matrix is:

[0049]

[0050] .

[0051] The second rotation is around Oy 1 The axis rotates, so y 1 The value of the axis remains unchanged (y 2 =y 1 ), Fig.10 For the rotation diagram:

[0052] α is the elevation angle of the geodetic coordinate system, x 1 y 1 z 1 is the intermediate coordinate system, x 2 y 2 z 2 is the body coordinate system.

[0053] From the geometric relationship in the figure above, we can see that:

[0054] Right now: ;

[0055] Therefore, the second coordinate transformation matrix is:

[0056]

[0057] .

[0058] In summary, we can get:

[0059]

[0060]

[0061] .

[0062] (x, y, z) are the coordinates of point A in the geodetic coordinate system, (x 2 ,y 2 ,z 2) is the coordinate of point A in the body coordinate system.

[0063] The above is the coordinate transformation formula for two rotations. Because point A is arbitrary, the above formula is valid for all points in space, and naturally for all points on the oil surface. As long as the coordinates of any point in space in the geodetic coordinate system are known, its coordinates in the body coordinate system can be calculated through the above formula, and vice versa.

[0064] Ignoring acceleration:

[0065] The equation of the oil surface in the geodetic coordinate system is z = 0 (assuming the center of the oil surface is the origin), and because:

[0066] ;

[0067] Therefore, the equation of the oil surface in the body coordinate system is:

[0068] ;

[0069] Then its normal vector is:

[0070] .

[0071] Assume that the oil surface angle in the body coordinate system is , , the aircraft attitude angle in the body coordinate system , , when acceleration is ignored, the following relationship exists:

[0072] ;

[0073] According to the definition of oil surface angle:

[0074] .

[0075] In summary, the calculation formula for the aircraft attitude angle in the body coordinate system is as follows:

[0076] = ;

[0077] ;

[0078] Conversely, the calculation formula for the aircraft attitude angle in the geodetic coordinate system is as follows:

[0079] = ;

[0080] ;

[0081] in , is the attitude angle of the geodetic coordinate system, , is the attitude angle of the body coordinate system. Its spatial meaning is that if the rotation angles of the two rotation methods satisfy the above formula, the spatial position of the obtained aircraft is the same, and the attitude angles in the two coordinate systems can be converted to each other.

[0082] The other parts of this embodiment are the same as any of the above embodiments 1-2, so they are not repeated here.

[0083] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for querying oil quantity data, characterized in that: Establish the intermediate coordinate system O-X1Y1Z1, the earth coordinate system O-XYZ and the body coordinate system O-X2Y2Z2, and realize the conversion between the earth coordinate system and the body coordinate system through the intermediate coordinate system by transforming the roll angle and pitch angle of the aircraft, so as to calculate the attitude angle of the aircraft in different coordinate systems, and use the fuel quantity database of one coordinate system to query the corresponding fuel quantity data in the earth coordinate system and the body coordinate system; The establishment operation of the intermediate coordinate system O-X1Y1Z1 is as follows: firstly, a standard earth coordinate system O-XYZ is established, and then, based on the earth coordinate system O-XYZ, the nose of the aircraft is raised by a pitch angle α, that is, the Y axis of the earth coordinate system O-XYZ is rotated clockwise by an angle α to obtain the intermediate coordinate system O-X1Y1Z1; The steps of establishing the body coordinate system O-X2Y2Z2 are specifically as follows: on the basis of the intermediate coordinate system O-X1Y1Z1, further, with the earth coordinate system O-XYZ as a reference, the intermediate coordinate system O-X1Y1Z1 is rotated by a roll angle β around the X-axis of the earth coordinate system O-XYZ to obtain the body coordinate system O-X2Y2Z2; After the geodetic coordinate system O-XYZ is converted to the intermediate coordinate system O-X1Y1Z1, the X axis between the two coordinate systems remains unchanged, X=X1, and the coordinate conversion relationship between the geodetic coordinate system O-XYZ and the intermediate coordinate system O-X1Y1Z1 is obtained: （1） Transform formula (1) to obtain formula (2): （2） According to formula (1) and formula (2), the coordinate transformation matrix between the earth coordinate system O-XYZ and the intermediate coordinate system O-X1Y1Z1 is obtained: （3） After the intermediate coordinate system O-X1Y1Z1 is rotated by a roll angle β around the X-axis of the earth coordinate system O-XYZ to obtain the body coordinate system O-X2Y2Z2, the Y-axis between the intermediate coordinate system O-X1Y1Z1 and the body coordinate system O-X2Y2Z2 remains unchanged, Y1=Y2, and the coordinate conversion relationship between the intermediate coordinate system O-X1Y1Z1 and the body coordinate system O-X2Y2Z2 is obtained: （4） Transforming formula (4) into formula (5): （5） According to formula (4) and formula (5), the coordinate transformation matrix between the intermediate coordinate system O-X1Y1Z1 and the body coordinate system O-X2Y2Z2 is obtained: （6） After the coordinate conversion relationship between the earth coordinate system O-XYZ and the intermediate coordinate system O-X1Y1Z1 and the coordinate conversion relationship between the intermediate coordinate system O-X1Y1Z1 and the body coordinate system O-X2Y2Z2 is obtained by calculation, the coordinate conversion relationship between the earth coordinate system O-XYZ and the intermediate coordinate system O-X1Y1Z1 and the body coordinate system O-X2Y2Z2 is converted according to the obtained coordinate conversion relationship, and a coordinate oil quantity database is established. According to the coordinate conversion relationship between the three coordinates, the oil quantity database is queried. The coordinate conversion relationship between the earth coordinate system O-XYZ and the body coordinate system O-X2Y2Z2 is as follows: （7） （8） （9）。

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