A helicopter attitude planning control system and method

Abstract

The present invention proposes a helicopter attitude planning control system and method, which belongs to the technical field of dynamic control of rotorcraft, and includes: a helicopter model determination module for determining N helicopter models of a helicopter in a target flight state; an RCS database construction module for calculating the RCS value of each helicopter model when performing radar scanning on each helicopter model under any radar incident direction, and constructing an RCS database; an RCS mean value determination module for determining the RCS mean value of any radar incident direction; a target incident direction determination module for determining the radar incident direction with the smallest RCS mean value as the target incident direction; and a helicopter attitude adjustment module for adjusting the positional relationship of the helicopter relative to the target radar scanning source according to the target incident direction and the position of the target radar scanning source. The optimal positional relationship between the helicopter and the target radar transmitting source is planned, and the stealth performance of the helicopter is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of dynamic control of rotorcraft, and in particular to a helicopter attitude planning control system and method. Background Art

[0002] Radar Cross Section (RCS) is a physical quantity that measures the ability of an aircraft to reflect electromagnetic waves. It is defined by the ratio of the radar echo energy reflected from the surface of the aircraft to the incident wave energy. The smaller the RCS, the better the stealth of the aircraft. At the same time, RCS is also the main basis for detection radar to search and identify aircraft.

[0003] The most significant difference between helicopters and fixed-wing aircraft is that helicopters have rotating parts such as the main rotor and tail rotor. The RCS of fixed-wing aircraft at the same angle is only a fixed value. Even if the radar wave irradiates the helicopter in flight from the same angle, its RCS value is also periodically changing dynamically because its rotating parts such as the main rotor and tail rotor are constantly rotating. In addition, there are many types of helicopters in the world, each of which has its own specific RCS characteristics, and the RCS at different angles is different, and the probability of radar detecting a helicopter from different azimuths is also different. Therefore, if a general numerical calculation method can be used to establish a dynamic RCS database of helicopter targets, it is of great significance to be able to plan and control the optimal stealth azimuth of the helicopter based on this database. Summary of the invention

[0004] The purpose of the present invention is to provide a helicopter attitude planning control system and method, which realizes the planning of the optimal position relationship between the helicopter and the target radar emission source and improves the stealth performance of the helicopter.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A helicopter attitude planning and control system, comprising:

[0007] A helicopter model determination module, used to determine N helicopter models of a helicopter in a target flight state; the target flight state includes a target flight altitude and a target flight speed;

[0008] An RCS database construction module is used to calculate the RCS values ​​of the N helicopter models when performing radar scanning on the N helicopter models under any radar incident direction, and to construct an RCS database of the helicopter; the radar incident direction includes a positional relationship of a radar scanning source in space relative to the helicopter;

[0009] An RCS mean value determination module is used to determine the RCS mean value of any radar incident direction under the target flight state; the RCS mean value is the average value of the RCS values ​​of N helicopter models under the radar incident direction;

[0010] A target incident direction determination module, used to determine the radar incident direction with the smallest RCS mean as the target incident direction;

[0011] The helicopter attitude adjustment module is used to adjust the position relationship of the helicopter relative to the target radar scanning source according to the target incident direction and the position of the target radar scanning source.

[0012] Optionally, the helicopter model determination module includes:

[0013] a target fuselage model determination unit, used to determine a target fuselage model of the helicopter under a target flight state; the target fuselage model is a model obtained by combining a factory fuselage model of the helicopter with a set of trim parameters uniquely determined under the target flight state; the trim parameters include a helicopter attitude angle, a lateral cyclic pitch control amount, a longitudinal cyclic pitch control amount, a main rotor collective pitch control amount, and a tail rotor collective pitch control amount;

[0014] A rotor model determination unit, used to determine N rotor models of the helicopter rotor in the target flight state according to a preset interval angle; N = 360° / preset interval angle; the N rotor models are models when the helicopter rotor rotates at different preset interval angles relative to the target fuselage model;

[0015] The helicopter model determination unit is used to determine N helicopter models of the helicopter in the target flight state according to the target fuselage model and the N rotor models.

[0016] Optionally, the helicopter model determination module includes:

[0017] a target fuselage model determination unit, used to determine a target fuselage model of the helicopter under a target flight state; the target fuselage model is a model obtained by combining a factory fuselage model of the helicopter with a set of trim parameters uniquely determined under the target flight state; the trim parameters include a helicopter attitude angle, a lateral cyclic pitch control amount, a longitudinal cyclic pitch control amount, a main rotor collective pitch control amount, and a tail rotor collective pitch control amount;

[0018] A blade number determination unit, used to determine the number of blades of the helicopter rotor;

[0019] A rotor model determination unit, used to determine, according to the number of blades and the preset interval angle, N rotor models between any two adjacent blades of the helicopter rotor in the target flight state; N = 360° / number of blades / preset interval angle; the N rotor models are models when the helicopter rotor rotates at different preset interval angles relative to the target fuselage model;

[0020] The helicopter model determination unit is used to determine N helicopter models of the helicopter in the target flight state according to the target fuselage model and the N rotor models.

[0021] Optionally, the helicopter model determination module further includes:

[0022] The rotor model periodic filling unit is used to determine the other M rotor models of the helicopter rotor in the target flight state based on the periodic rule of rotor rotation according to the N rotor models and the number of blades; M=N*(number of blades-1).

[0023] Corresponding to the aforementioned helicopter attitude planning and control system, the present invention also provides a helicopter attitude planning and control method, comprising the following steps:

[0024] Determine N helicopter models of the helicopter in a target flight state; the target flight state includes a target flight altitude and a target flight speed;

[0025] When performing radar scanning on the N helicopter models under any radar incident direction, RCS values ​​of the N helicopter models are calculated to construct an RCS database of the helicopter; the radar incident direction includes a positional relationship of a radar scanning source in space relative to the helicopter;

[0026] Determine the RCS mean value in any radar incident direction under the target flight state; the RCS mean value is the average value of the RCS values ​​of the N helicopter models under the radar incident direction;

[0027] Determine the radar incident direction with the smallest RCS mean as the target incident direction;

[0028] According to the target incident direction and the position of the target radar scanning source, the position relationship of the helicopter relative to the target radar scanning source is adjusted.

[0029] Optionally, the determining N helicopter models of the helicopter in the target flight state specifically includes:

[0030] Determine a target fuselage model of the helicopter under the target flight state; the target fuselage model is a model obtained by combining a factory fuselage model of the helicopter with a unique set of trim parameters determined under the target flight state; the trim parameters include a helicopter attitude angle, a lateral cyclic pitch control amount, a longitudinal cyclic pitch control amount, a main rotor collective pitch control amount, and a tail rotor collective pitch control amount;

[0031] According to the preset interval angle, determine N rotor models of the helicopter rotor in the target flight state; N = 360° / preset interval angle; the N rotor models are models when the helicopter rotor rotates at different preset interval angles relative to the target fuselage model;

[0032] According to the target fuselage model and the N rotor models, N helicopter models of the helicopter in the target flight state are determined.

[0033] Optionally, the determining N helicopter models of the helicopter in the target flight state specifically includes:

[0034] Determine a target fuselage model of the helicopter under a target flight state; the target fuselage model is a model obtained by combining a factory fuselage model of the helicopter with a unique set of trim parameters determined under the target flight state; the trim parameters include a helicopter attitude angle, a lateral cyclic pitch control amount, a longitudinal cyclic pitch control amount, a main rotor collective pitch control amount, and a tail rotor collective pitch control amount;

[0035] Determine the number of blades on the helicopter rotor;

[0036] According to the number of blades and the preset interval angle, determine N rotor models between any two adjacent blades of the helicopter rotor in the target flight state; N = 360° / number of blades / preset interval angle; the N rotor models are models when the helicopter rotor rotates at different preset interval angles relative to the target fuselage model;

[0037] According to the target fuselage model and the N rotor models, N helicopter models of the helicopter in the target flight state are determined.

[0038] Optionally, after determining N rotor models between any two adjacent blades of the helicopter rotor in the target flight state according to the number of blades and the preset interval angle, the helicopter attitude planning and control method further includes:

[0039] According to the N rotor models and the number of blades, the other M rotor models of the helicopter rotor in the target flight state are determined based on the periodic rule of rotor rotation; M=N*(number of blades-1).

[0040] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0041] The present invention provides a helicopter attitude planning control system and method. The helicopter attitude planning control system comprises: a helicopter model determination module for determining N helicopter models in a target flight state; the target flight state comprises a target flight altitude and a target flight speed; an RCS database construction module for calculating RCS values ​​of the N helicopter models when performing radar scanning on the N helicopter models in any radar incident direction to construct a helicopter RCS database; an RCS mean value determination module for determining the RCS mean value of any radar incident direction in the target flight state; a target incident direction determination module for determining the radar incident direction with the smallest RCS mean value as the target incident direction; and a helicopter attitude adjustment module for adjusting the positional relationship of the helicopter relative to a target radar scanning source according to the target incident direction and the position of the target radar scanning source. The present invention determines a helicopter model based on a target flight state of the helicopter, and establishes an RCS database under different radar incident directions. According to the RCS database, the target radar incident direction with the highest stealth performance for a radar scanning source of the helicopter in the target flight state can be conveniently determined. When the position of the target radar scanning source is determined, the positional relationship between the helicopter and the target radar scanning source can be adjusted according to the target radar incident direction to ensure the stealth performance of the helicopter relative to the target radar scanning source. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 A structural block diagram of a helicopter attitude planning control system provided in Example 1 of the present invention;

[0044] Figure 2 A flowchart of a helicopter attitude planning and control method provided in Example 2 of the present invention;

[0045] Figure 3 A schematic diagram of the conversion relationship between the earth axis system and the body axis system in the method provided in Example 2 of the present invention;

[0046] Figure 4 This is a schematic diagram of the spatial angle coordinate system in the method provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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. Based on the embodiments of 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.

[0048] The purpose of the present invention is to provide a helicopter attitude planning control system and method, which realizes the planning of the optimal position relationship between the helicopter and the target radar emission source and improves the stealth performance of the helicopter.

[0049] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] Embodiment 1:

[0051] This embodiment provides a helicopter attitude planning control system, such as Figure 1 As shown in the structural schematic diagram, the system includes:

[0052] A helicopter model determination module 1 is used to determine N helicopter models of a helicopter in a target flight state; the target flight state includes a target flight altitude and a target flight speed;

[0053] The RCS database construction module 2 is used to calculate the RCS values ​​of the N helicopter models when performing radar scanning on the N helicopter models under any radar incident direction, so as to construct an RCS database of the helicopter; the radar incident direction includes the position relationship of a radar scanning source in space relative to the helicopter; there are many solutions for calculating RCS data, such as the classical geometric optics method or the physical optics method, etc. These methods are very mature and can be directly applied, so the calculation method of RCS data does not belong to the scope of the present invention.

[0054] RCS mean value determination module 3, used to determine the RCS mean value of any radar incident direction under the target flight state; the RCS mean value is the average value of the RCS values ​​of N helicopter models under the radar incident direction;

[0055] A target incident direction determination module 4 is used to determine the radar incident direction with the smallest RCS mean as the target incident direction;

[0056] The helicopter attitude adjustment module 5 is used to adjust the position relationship of the helicopter relative to the target radar scanning source according to the target incident direction and the position of the target radar scanning source.

[0057] In this embodiment, the helicopter model determination module 1 includes:

[0058] A target fuselage model determination unit 11 is used to determine a target fuselage model of the helicopter under a target flight state; the target fuselage model is a model obtained by combining a factory fuselage model of the helicopter with a set of trim parameters uniquely determined under the target flight state; the trim parameters include a helicopter attitude angle, a lateral cyclic pitch control amount, a longitudinal cyclic pitch control amount, a main rotor collective pitch control amount, and a tail rotor collective pitch control amount;

[0059] The rotor model determination unit 13 is used to determine N rotor models of the helicopter rotor in the target flight state according to a preset interval angle; N=360° / preset interval angle; the N rotor models are models when the helicopter rotor rotates at different preset interval angles relative to the target fuselage model;

[0060] The helicopter model determination unit 14 is used to determine N helicopter models of the helicopter in the target flight state according to the target fuselage model and the N rotor models.

[0061] In some other embodiments, the helicopter model determination module 1 includes:

[0062] A target fuselage model determination unit 11 is used to determine a target fuselage model of the helicopter under a target flight state; the target fuselage model is a model obtained by combining a factory fuselage model of the helicopter with a set of trim parameters uniquely determined under the target flight state; the trim parameters include a helicopter attitude angle, a lateral cyclic pitch control amount, a longitudinal cyclic pitch control amount, a main rotor collective pitch control amount, and a tail rotor collective pitch control amount;

[0063] A blade number determination unit 12, used to determine the number of blades of the helicopter rotor;

[0064] The rotor model determination unit 13 is used to determine N rotor models between any two adjacent blades of the helicopter rotor in the target flight state according to the number of blades and the preset interval angle; N = 360° / number of blades / preset interval angle; the N rotor models are models when the helicopter rotor rotates at different preset interval angles relative to the target fuselage model;

[0065] The helicopter model determination unit 14 is used to determine N helicopter models of the helicopter in the target flight state according to the target fuselage model and the N rotor models.

[0066] As an extended solution, the helicopter model determination module 1 further includes:

[0067] The rotor model periodic filling unit 15 is used to determine the other M rotor models of the helicopter rotor in the target flight state according to the N rotor models and the number of blades based on the periodic rule of rotor rotation; M=N*(number of blades-1).

[0068] Embodiment 2:

[0069] like Figure 2 The flowchart shown corresponds to a helicopter attitude planning control system provided in Example 1. This embodiment provides a helicopter attitude planning control method, including the following steps:

[0070] S1. Determine N helicopter models of a helicopter in a target flight state; the target flight state includes a target flight altitude and a target flight speed;

[0071] Step S1 specifically includes:

[0072] S11, determining a target fuselage model of the helicopter in the target flight state; the target fuselage model is a model obtained by combining a factory fuselage model of the helicopter with a set of trim parameters uniquely determined in the target flight state; the trim parameters include helicopter attitude angle, lateral cyclic pitch control amount, longitudinal cyclic pitch control amount, main rotor collective pitch control amount, and tail rotor collective pitch control amount;

[0073] When a helicopter is in different flight states, it will present different flight attitudes in space, and when the helicopter's flight attitude changes, its geometric shape model will change accordingly. Therefore, it is necessary to determine its flight attitude according to the given helicopter flight state in order to obtain an accurate geometric shape model of the helicopter under different flight states.

[0074] The flight attitude of a helicopter is determined by the equilibrium attitude angle of the static component (i.e., the fuselage) and the control amount of the dynamic component (the main rotor and the tail rotor). When the equilibrium attitude angle of the static component and the control amount of the dynamic component are determined, the flight attitude of the helicopter is uniquely determined. When the flight state of a given helicopter is known, the equilibrium attitude angle of the static component and the control amount of the dynamic component under a certain flight state can be calculated through flight mechanics balancing means, and then the geometric shape model of the helicopter under different flight states can be established based on the above-mentioned equilibrium attitude angle and control amount data.

[0075] There are two equilibrium attitude angles for the static parts, including the pitch angle θ and the roll angle Φ; there are four control variables for the dynamic parts, including the total pitch control of the main rotor. Lateral and longitudinal cyclic pitch controls A1 and B1, and collective pitch control of the tail rotor

[0076] Taking a single-rotor helicopter with a tail rotor as an example, first define the earth axis system (i.e., the ground coordinate system) and the body axis system (i.e., the body coordinate system).

[0077] Earth's Axis System O D X D Y D Z D Used to determine the attitude angle (pitch angle and roll angle) and heading of the helicopter, the origin O D Fixed at a point on the ground, X D Pointing to due north, Y D Pointing upwards to the plumb line, Z D According to the right-hand rule (X D Z D Parallel to the ground). For the convenience of calculation, the earth axis is translated to the helicopter, that is, O D Coincident with the helicopter's center of gravity O.

[0078] Body axis O B X B Y B Z B Origin O B Located at the helicopter's center of gravity, X B The axis points to the positive direction of the nose, which is consistent with the X D Z D The angle θ between the planes is the pitch angle of the helicopter, with the head up being positive and the angle with the X D Y D The angle Ψ between the planes is the azimuth of the helicopter, with left deviation being positive. B Located in the longitudinal symmetry plane of the body, perpendicular to X B Axis direction, X B Y B Plane and Y D The angle Φ is the helicopter's roll angle, with rightward deflection being positive. B The axis obeys the right-hand rule.

[0079] The conversion relationship between the earth axis system and the body axis system can be seen in the attached Figure 3 .

[0080] Assume that the collective pitch control of the main rotor is The lateral and longitudinal cyclic pitch control are A1 and B1 respectively, and the collective pitch control of the tail rotor is The helicopter's gravity is G.

[0081] Based on the momentum blade element theory, the three components of the aerodynamic force of the main rotor under the body axis system can be expressed as:

[0082]

[0083]

[0084]

[0085] The three components of aerodynamic torque can be expressed as:

[0086]

[0087]

[0088]

[0089] The aerodynamic force and aerodynamic moment components of the tail rotor under the body axis system can be expressed as:

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

[0096] The aerodynamic force and aerodynamic moment components of the fuselage under the body axis system can be obtained through wind tunnel test data or empirical formulas:

[0097] F F-BX ,F F-BY ,F F-BZ ,M F-BX ,M F-BY ,M F-BZ

[0098] And, the aerodynamic force and aerodynamic moment body axis system components jointly generated by the horizontal tail and vertical tail of the helicopter are:

[0099] F W-BX ,F W-BY ,F W-BZ ,M W-BX ,M W-BY ,M W-BZ

[0100] According to the coordinate transformation relationship from the earth axis system to the body axis system, the three components of the helicopter gravity G in the body axis system can be obtained as follows:

[0101] G BX = -GsinΘ

[0102] G BY = -GcosΘcosΦ

[0103] G BZ =GcosΘsinΦ

[0104] According to the aerodynamic and moment balance conditions under the trim state, the helicopter flight dynamics balance equation can be listed as follows:

[0105]

[0106]

[0107]

[0108]

[0109]

[0110]

[0111] By solving the above equations using numerical methods, we can obtain the two equilibrium attitude angles Θ, Φ and four control variables when the helicopter is flying in any state: A1, B1,

[0112] By solving the helicopter flight dynamics balance equation, we can understand the real-time attitude angle of the helicopter flight and the movement laws of the rotor / tail rotor, and then establish helicopter models in different states to provide accurate model input for RCS calculation.

[0113] S12, determining N rotor models of the helicopter rotor in the target flight state according to a preset interval angle; N = 360° / preset interval angle; the N rotor models are models of the helicopter rotor when it rotates at different preset interval angles relative to the target fuselage model;

[0114] Since the main rotor and tail rotor of the helicopter are always rotating, when they are at different rotation angles, the relative position relationship with the fuselage will change, and the geometric shape model of the helicopter will also change. Therefore, it is also necessary to divide the rotation angle of its moving parts based on the helicopter geometric shape model of a given flight state, so as to obtain the helicopter geometric shape model of the main rotor and tail rotor dynamically rotating under the given flight state. Since there is generally a fixed phase relationship between the rotation angles of the main rotor and the tail rotor, that is, the rotation angle of the other can be obtained by knowing the rotation angle of one of them, therefore, the present invention only divides the rotation angle of the main rotor. First, the total range of the rotor rotation angle is determined according to the number of blades, and then the division interval of the rotor rotation angle is given, and the rotation angle of the rotor is divided according to the division interval within the total rotation range.

[0115] The division interval of the rotor rotation angle must meet certain requirements: Assuming the radius of the rotor is R, the rotation speed is Ω, the radar wave wavelength is λ, and α is the angle between the incident direction of the radar wave and the blade plane, then the maximum micro-Doppler frequency shift F generated by the rotor rotation is max for:

[0116]

[0117] The maximum sampling time interval T divided by the rotor rotation angle s The following conditions should be met:

[0118]

[0119] The dimension of the rotor speed Ω is rad / s, so the maximum division interval of the rotor rotation angle δ (°) should satisfy:

[0120]

[0121] In summary, in each determined flight state, the helicopter's fuselage attitude angle and rotor (tail rotor) control amount are determined, and the number of divisions of the rotor rotation angle NUM_R should satisfy:

[0122]

[0123] S13. Determine N helicopter models of the helicopter in the target flight state according to the target fuselage model and the N rotor models.

[0124] S2. When performing radar scanning on the N helicopter models under any radar incident direction, calculating the RCS values ​​of the N helicopter models, and constructing an RCS database of the helicopter; the radar incident direction includes a positional relationship of a radar scanning source in space relative to the helicopter;

[0125] After determining the N models of the helicopter, it is necessary to calculate the RCS of the helicopter at multiple locations in space. To this end, the following Figure 4 The spatial angle coordinate system OXYZ shown in the figure has the O point located at the center of gravity of the helicopter body and the XY plane parallel to the ground. P is any point in the coordinate system OXYZ, using the angle coordinate system Describes the position of P, where θ is the angle between the line segment OP and the Z axis, and its range satisfies 0°≤θ≤180°. When P is located in the positive direction of the Z axis, θ=0°, and when P is located in the negative direction of the Z axis, θ=180°; P' is the projection of P on the XY plane, is the angle between the line segment OP' and the X-axis. θ is the pitch angle of the radar incident point relative to the helicopter. The yaw angle of the radar incident point relative to the helicopter.

[0126] Normally, the area outside the helicopter pitch angle of 60° and -60° does not belong to the key angle range. Therefore, the radar wave illumination azimuth set for establishing the helicopter dynamic RCS database is defined as:

[0127]

[0128] Pitch angle interval Δθ, yaw angle interval The total number of irradiation positions NUM_I is:

[0129]

[0130] For the same helicopter target, we first need to determine its flight state number i. For each flight state, there is a corresponding trim state TRIM_1, TRIM_2, ..., TRIM_i-1, TRIM_i. In each trim state, there is a certain helicopter attitude angle and control amount:

[0131]

[0132]

[0133] …

[0134]

[0135]

[0136] Therefore, each trim state TRIM_k (k=1,...,i) of the helicopter belongs to the first-level column of the database, that is, the complete helicopter dynamic RCS database should contain i first-level databases.

[0137] Radar wave irradiation direction The secondary columns belong to the database and are placed under the primary columns in the following matrix arrangement, that is, each primary database should contain NUM_I secondary databases.

[0138]

[0139] Under the same radar wave irradiation azimuth, the dynamic RCS of the helicopter with rotor rotation needs to be discretely sampled. The number of divisions of the rotor rotation angle is NUM_R, that is, each secondary database should contain NUM_R RCS data.

[0140] In summary, for a helicopter target, its complete dynamic RCS database should contain a total number of RCS data of i×NUM_I×NUM_R.

[0141] S3, determining the RCS mean value in any radar incident direction under the target flight state; the RCS mean value is the average value of the RCS values ​​of N helicopter models under the radar incident direction;

[0142] S4, determining the radar incident direction with the smallest RCS mean as the target incident direction;

[0143] S5. According to the target incident direction and the position of the target radar scanning source, adjust the position relationship of the helicopter relative to the target radar scanning source.

[0144] Embodiment 3:

[0145] The helicopter attitude planning and control method provided in this embodiment is substantially the same as the method provided in Embodiment 2, except that: Step S1 determines N helicopter models of the helicopter in the target flight state, specifically including:

[0146] S11, determining a target fuselage model of the helicopter in a target flight state; the target fuselage model is a model obtained by combining a factory fuselage model of the helicopter with a set of trim parameters uniquely determined in the target flight state; the trim parameters include helicopter attitude angle, lateral cyclic pitch control amount, longitudinal cyclic pitch control amount, main rotor collective pitch control amount and tail rotor collective pitch control amount;

[0147] S12, determining the number of blades of the helicopter rotor;

[0148] S13, determining N rotor models between any two adjacent blades of the helicopter rotor in the target flight state according to the number of blades and the preset interval angle; N = 360° / number of blades / preset interval angle; the N rotor models are models when the helicopter rotor rotates at different preset interval angles relative to the target fuselage model;

[0149] After accurately generating the model of the helicopter in trimmed state, the fuselage is kept stationary, and the rotor and tail rotor rotate according to their respective speeds and trim control laws. If the helicopter rotor has N blades, the total range of the rotor rotation angle is 0° to 360° / N, and the RCS data within the remaining 360°(N-1) / N angle range is directly sequenced based on the periodic law.

[0150] That is, as an extended solution, the other M rotor models of the helicopter rotor in the target flight state can be determined according to the N rotor models and the number of blades based on the periodic rule of rotor rotation; M=N*(number of blades-1).

[0151] S14. Determine N helicopter models of the helicopter in the target flight state according to the target fuselage model and the N rotor models.

[0152] The helicopter attitude planning control provided by the present invention is illustrated below with reference to a specific example: a general-purpose helicopter is trimmed. At a certain flight altitude, the flight speeds of the helicopter are 0 m / s, 5 m / s, 10 m / s, ..., 55 m / s, 60 m / s, for a total of 13 flight states, i.e., 13 trim states, i.e., 13 primary databases can be established.

[0153] The 13 flight states of this type of helicopter are trimmed to obtain 13 groups of attitude angles and control variables of the helicopter:

[0154]

[0155] Next, the continuous periodic signal of the rotor is discretely sampled and divided. This type of helicopter has 4 blades, so the rotor rotation angle is only divided for the 90° angle range of the rotor, and the RCS data within the remaining 270° angle is directly filled in sequence based on the periodic law. When the present invention illustrates the beneficial effects, it does not require the extraction of the micro-Doppler effect of the rotor, so the angle division interval can be appropriately relaxed for illustration (in the actual process of establishing a dynamic RCS database for helicopters, the rotor rotation angle division interval should be determined according to specific needs). Here, the angle division interval is set to 10°, and a total of 36 RCS data can be obtained within one rotation of the rotor, that is, each secondary database contains 36 RCS data.

[0156] In the spatial angle coordinate system OXYZ, the nose of this type of helicopter points to the X axis, and the given radar wave irradiation azimuth range is: pitch angle 80° to 110°, step 3°, a total of 11 pitch angles; yaw angle -30° to 30°, step 3°, a total of 21 yaw angles. A total of 231 radar wave irradiation azimuths, that is, 231 secondary databases. The RCS database shown in Table 1 is obtained:

[0157]

[0158]

[0159] Table 1 shows part of the first-level RCS database of this type of helicopter when the flight speed is 0m / s (TRIM_1), for illustration only (the complete dynamic RCS database of this type of helicopter contains 13 first-level databases, and only part of the first-level database is given here). The first column in Table 1 represents the serial number of the second-level database, and each first-level database has 231 second-level databases. For the convenience of data viewing, Table 1 only gives the RCS data of 9 angles of rotor rotation angles of 0°, 10°, ..., 80°, and the remaining angles can be filled in periodic sequences. The RCS data in the table are obtained after algebraic operations with a constant based on the original calculated value, and the dimension is dBsm decibels per square meter, with 2 decimal places retained.

[0160] The program part in the technology can be considered as a "product" or "manufactured product" in the form of executable code and / or related data, which is participated in or realized by computer-readable media. Tangible and permanent storage media can include any memory or storage used by any computer, processor, or similar device or related module. For example, various semiconductor memories, tape drives, disk drives or any similar devices that can provide storage functions for software.

[0161] All or part of the software may sometimes communicate over a network, such as the Internet or other communications network. Such communications can load software from one computer device or processor to another. For example: from a server or host computer of a video target detection device to a hardware platform of a computer environment, or other computer environment that implements the system, or a system with similar functions related to providing information required for target detection. Therefore, another medium capable of transmitting software elements can also be used as a physical connection between local devices, such as light waves, radio waves, electromagnetic waves, etc., transmitted through cables, optical cables or air. Physical media used to carry carriers, such as cables, wireless connections or optical cables and the like, can also be considered as media that carry software. As used herein, unless limited to tangible "storage" media, other terms referring to computer or machine "readable media" refer to media involved in the process of the processor executing any instructions.

[0162] Specific examples are used in this article, but the above description is only to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas; technicians in this field should understand that the modules or steps of the present invention can be implemented by a general computer device, and optionally, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by a computing device, or they can be made into individual integrated circuit modules, or multiple modules or steps in them can be made into a single integrated circuit module for implementation. The present invention is not limited to any specific combination of hardware and software.

[0163] Meanwhile, for those skilled in the art, according to the concept of the present invention, there will be changes in the specific implementation and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A helicopter attitude planning and control system, characterized in that: The helicopter attitude planning and control system comprises: A helicopter model determination module, used to determine N helicopter models of a helicopter in a target flight state; the target flight state includes a target flight altitude and a target flight speed; The RCS database construction module is used to calculate the RCS values ​​of the N helicopter models when performing radar scanning on the N helicopter models under any radar incident direction, and to construct an RCS database of the helicopter; the radar incident direction includes a positional relationship of a radar scanning source in space relative to the helicopter; the RCS database of the helicopter includes a total number of RCS data of i×NUM_I×NUM_R; i is the number of flight states of the helicopter; NUM_I is the number of total irradiation azimuths; NUM_R is the number of divisions of the rotor rotation angle; the number of total irradiation azimuths can be determined according to the following formula: Where Δθ is the pitch angle interval, is the yaw angle interval; An RCS mean value determination module is used to determine the RCS mean value of any radar incident direction under the target flight state; the RCS mean value is the average value of the RCS values ​​of N helicopter models under the radar incident direction; A target incident direction determination module, used to determine the radar incident direction with the smallest RCS mean as the target incident direction; A helicopter attitude adjustment module, used to adjust the position relationship of the helicopter relative to the target radar scanning source according to the target incident direction and the position of the target radar scanning source; The helicopter model determination module comprises: a target fuselage model determination unit, used to determine a target fuselage model of the helicopter under a target flight state; the target fuselage model is a model obtained by combining a factory fuselage model of the helicopter with a set of trim parameters uniquely determined under the target flight state; the trim parameters include a helicopter attitude angle, a lateral cyclic pitch control amount, a longitudinal cyclic pitch control amount, a main rotor collective pitch control amount, and a tail rotor collective pitch control amount; A rotor model determination unit, used to determine N rotor models of the helicopter rotor in the target flight state according to a preset interval angle; N = 360° / preset interval angle; the N rotor models are models when the helicopter rotor rotates at different preset interval angles relative to the target fuselage model; The helicopter model determination unit is used to determine N helicopter models of the helicopter in the target flight state according to the target fuselage model and the N rotor models.

2. A helicopter attitude planning and control system, characterized in that: The helicopter attitude planning and control system comprises: A helicopter model determination module, used to determine N helicopter models of a helicopter in a target flight state; the target flight state includes a target flight altitude and a target flight speed; The RCS database construction module is used to calculate the RCS values ​​of the N helicopter models when performing radar scanning on the N helicopter models under any radar incident direction, and to construct an RCS database of the helicopter; the radar incident direction includes a positional relationship of a radar scanning source in space relative to the helicopter; the RCS database of the helicopter includes a total number of RCS data of i×NUM_I×NUM_R; i is the number of flight states of the helicopter; NUM_I is the number of total irradiation azimuths; NUM_R is the number of divisions of the rotor rotation angle; the number of total irradiation azimuths can be determined according to the following formula: Where Δθ is the pitch angle interval, is the yaw angle interval; An RCS mean value determination module is used to determine the RCS mean value of any radar incident direction under the target flight state; the RCS mean value is the average value of the RCS values ​​of N helicopter models under the radar incident direction; A target incident direction determination module, used to determine the radar incident direction with the smallest RCS mean as the target incident direction; A helicopter attitude adjustment module, used to adjust the position relationship of the helicopter relative to the target radar scanning source according to the target incident direction and the position of the target radar scanning source; The helicopter model determination module comprises: a target fuselage model determination unit, used to determine a target fuselage model of the helicopter under a target flight state; the target fuselage model is a model obtained by combining a factory fuselage model of the helicopter with a set of trim parameters uniquely determined under the target flight state; the trim parameters include a helicopter attitude angle, a lateral cyclic pitch control amount, a longitudinal cyclic pitch control amount, a main rotor collective pitch control amount, and a tail rotor collective pitch control amount; A blade number determination unit, used to determine the number of blades of the helicopter rotor; A rotor model determination unit, used to determine, according to the number of blades and the preset interval angle, N rotor models between any two adjacent blades of the helicopter rotor in the target flight state; N = 360° / number of blades / preset interval angle; the N rotor models are models when the helicopter rotor rotates at different preset interval angles relative to the target fuselage model; The helicopter model determination unit is used to determine N helicopter models of the helicopter in the target flight state according to the target fuselage model and the N rotor models.

3. The helicopter attitude planning and control system according to claim 2, characterized in that: The helicopter model determination module also includes: The rotor model periodic filling unit is used to determine the other M rotor models of the helicopter rotor in the target flight state based on the periodic rule of rotor rotation according to the N rotor models and the number of blades; M=N*(number of blades-1).

4. A helicopter attitude planning and control method, characterized in that: The helicopter attitude planning and control method comprises: Determine N helicopter models of the helicopter in a target flight state; the target flight state includes a target flight altitude and a target flight speed; When performing radar scanning on N helicopter models under any radar incident direction, the RCS values ​​of the N helicopter models are calculated to construct an RCS database of the helicopter; the radar incident direction includes a positional relationship of a radar scanning source in space relative to the helicopter; the RCS database of the helicopter includes a total number of RCS data of i×NUM_I×NUM_R; i is the number of flight states of the helicopter; NUM_I is the number of total irradiation azimuths; NUM_R is the number of divisions of the rotor rotation angle; the number of total irradiation azimuths can be determined according to the following formula: Where Δθ is the pitch angle interval, is the yaw angle interval; Determine the RCS mean value in any radar incident direction under the target flight state; the RCS mean value is the average value of the RCS values ​​of the N helicopter models under the radar incident direction; Determine the radar incident direction with the smallest RCS mean as the target incident direction; According to the target incident direction and the position of the target radar scanning source, adjusting the position relationship of the helicopter relative to the target radar scanning source; The determining of N helicopter models of the helicopter in the target flight state specifically includes: Determine a target fuselage model of the helicopter under the target flight state; the target fuselage model is a model obtained by combining a factory fuselage model of the helicopter with a unique set of trim parameters determined under the target flight state; the trim parameters include a helicopter attitude angle, a lateral cyclic pitch control amount, a longitudinal cyclic pitch control amount, a main rotor collective pitch control amount, and a tail rotor collective pitch control amount; According to the preset interval angle, determine N rotor models of the helicopter rotor in the target flight state; N = 360° / preset interval angle; the N rotor models are models when the helicopter rotor rotates at different preset interval angles relative to the target fuselage model; According to the target fuselage model and the N rotor models, N helicopter models of the helicopter in the target flight state are determined.

5. A helicopter attitude planning and control method, characterized in that: The helicopter attitude planning and control method comprises: Determine N helicopter models of the helicopter in a target flight state; the target flight state includes a target flight altitude and a target flight speed; When performing radar scanning on N helicopter models under any radar incident direction, the RCS values ​​of the N helicopter models are calculated to construct an RCS database of the helicopter; the radar incident direction includes a positional relationship of a radar scanning source in space relative to the helicopter; the RCS database of the helicopter includes a total number of RCS data of i×NUM_I×NUM_R; i is the number of flight states of the helicopter; NUM_I is the number of total irradiation azimuths; NUM_R is the number of divisions of the rotor rotation angle; the number of total irradiation azimuths can be determined according to the following formula: Where Δθ is the pitch angle interval, is the yaw angle interval; Determine the RCS mean value in any radar incident direction under the target flight state; the RCS mean value is the average value of the RCS values ​​of the N helicopter models under the radar incident direction; Determine the radar incident direction with the smallest RCS mean as the target incident direction; According to the target incident direction and the position of the target radar scanning source, adjusting the position relationship of the helicopter relative to the target radar scanning source; The determining of N helicopter models of the helicopter in the target flight state specifically includes: Determine a target fuselage model of the helicopter under a target flight state; the target fuselage model is a model obtained by combining a factory fuselage model of the helicopter with a unique set of trim parameters determined under the target flight state; the trim parameters include a helicopter attitude angle, a lateral cyclic pitch control amount, a longitudinal cyclic pitch control amount, a main rotor collective pitch control amount, and a tail rotor collective pitch control amount; Determine the number of blades on the helicopter rotor; According to the number of blades and the preset interval angle, determine N rotor models between any two adjacent blades of the helicopter rotor in the target flight state; N = 360° / number of blades / preset interval angle; the N rotor models are models when the helicopter rotor rotates at different preset interval angles relative to the target fuselage model; According to the target fuselage model and the N rotor models, N helicopter models of the helicopter in the target flight state are determined.

6. The helicopter attitude planning and control method according to claim 5, characterized in that: After determining, according to the number of blades and the preset interval angle, the N rotor models between any two adjacent blades of the helicopter rotor in the target flight state, the helicopter attitude planning and control method further includes: According to the N rotor models and the number of blades, the other M rotor models of the helicopter rotor in the target flight state are determined based on the periodic rule of rotor rotation; M=N*(number of blades-1).

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