Aircraft balance parameter adjustment test bench and parameter adjustment method thereof

Abstract

The present invention relates to an aircraft balance parameter adjustment test bench and its parameter adjustment method, comprising an upper turbojet engine mounting platform, a central telescopic support and a spherical node, and a bottom hemispherical support. The upper turbojet engine mounting platform is elastically connected to the central telescopic support and the spherical node via a connecting spring, and is slidably connected to a support slide groove via a hydraulic telescopic rod. The central telescopic support and the spherical node are slidably connected to the bottom hemispherical support via a disk limiter and a hollow cylindrical force measurement limiter. A BP neural network model is used to adjust the test bench's angle control PID parameters and length control PID parameters in real time, changing the lengths and angles of the four hydraulic telescopic rods to achieve turbojet engine balance. Furthermore, the total lift and thrust data of each turbojet engine are integrated to optimize the turbojet engine control PID parameters, thereby meeting the requirements of turbojet engine aircraft testing and application. This simplifies operation, improves efficiency, and reduces costs while ensuring personnel and equipment safety.

Description

Technical Field

[0001] The present invention belongs to the technical field of turbojet engine aircraft testing and application supporting equipment, specifically an aircraft balance parameter adjustment test bench and a parameter adjustment method thereof, which are used for turbojet engine aircraft debugging and testing. Background Art

[0002] In recent years, with the development of aviation science and technology, turbojet engine aircraft have been used more and more widely. Compared with conventional unmanned aerial vehicles, turbojet engine aircraft have the advantages of small size, light weight and low cost, and have rich application prospects both in military and civilian fields.

[0003] Flight control is an important part of turbojet engine aircraft, among which PID control testing and debugging are important links in the development of unmanned aerial vehicles. PID control is a relatively mature control method with a relatively simple algorithm, high stability and good robustness. Especially during the startup process of turbojet engine aircraft, PID control is the key to maintaining the stability of the aircraft.

[0004] At present, the testing and debugging of turbojet engine aircraft are all done by fixing the aircraft on an axis so that the aircraft can only rotate around the axis, or fixing the aircraft on a universal joint for testing, which limits the movement of the aircraft to a certain extent; the relative position of the turbojet engine cannot be changed when installing the aircraft, and the shape of the aircraft can only be based on default specifications; the turbojet engine must be turned off when debugging the aircraft PID parameters, and the test can continue after the debugging is completed; due to the lack of safety protection devices, in the event of flight control failure or external disturbance, accidents such as collisions and falls are prone to occur, causing casualties and financial losses, and the aircraft has defects such as low efficiency and insufficient safety.

[0005] An aircraft balance parameter adjustment test bench and parameter adjustment method need to meet the following requirements: the relative position of the turbojet engine can be adjusted according to actual needs, or the turbojet engine aircraft frame can be optimized through test methods; the movement restrictions of the turbojet engine aircraft during the test are reduced, while ensuring that accidents such as collisions and falls do not occur during the test; the PID control parameters can be adjusted during the test, while providing a basis for judging whether the PID control parameters are optimal; to meet the flight control test requirements of the turbojet engine aircraft, the test bench is required to have a modular structure and simple installation and disassembly. Summary of the Invention

[0006] In response to the problem of lack of corresponding test benches for aircraft parameter adjustment tests, the present invention proposes an aircraft balance parameter adjustment test bench and its parameter adjustment method, which can meet the requirements of turbojet engine aircraft parameter adjustment tests such as free installation of turbojet engines, unrestricted aircraft movement, safety protection, real-time adjustment of PID control parameters, and optimization judgment of PID control parameters, thereby realizing PID parameter debugging and testing of turbojet engine aircraft.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] An aircraft balance parameter adjustment test bench comprises an upper turbojet engine mounting platform (1), a middle telescopic support and a spherical node (2), and a bottom hemispherical support (3);

[0009] The upper turbojet engine mounting platform (1) is elastically connected to the middle telescopic support and spherical node (2) via a connecting spring (2-7), and is slidably connected to the support chute (1-4) via a hydraulic telescopic rod (2-1); the middle telescopic support and spherical node (2) is slidably connected to the bottom hemispherical support (3) via a disc limiter (2-6) and a hollow cylindrical force measuring limiter (3-2).

[0010] The technical solution is further optimized, wherein the upper turbojet engine mounting platform (1) comprises a turbojet engine mounting ring (1-1), a telescopic inner rod (1-2), a telescopic outer rod (1-3) and a supporting slide groove (1-4); the turbojet engine mounting ring (1-1) is fixedly connected to the telescopic inner rod (1-2), and the telescopic inner rod (1-2) can slide within the telescopic outer rod (1-3), thereby adjusting the position of the engine mounting ring (1-1) to achieve the dimensional requirements required for testing, and the relative position of the telescopic outer rod (1-3) and the telescopic inner rod (1-2) can be fixed.

[0011] The technical solution is further optimized, and the middle telescopic support and spherical node (2) includes a hydraulic telescopic rod (2-1), a hydraulic telescopic rod housing (2-2), a telescopic support rotating support (2-3), a spherical node (2-4), a force measuring connecting rod (2-5), a disc limiter (2-6) and a connecting spring (2-7); the hydraulic telescopic rod (2-1) can slide in the hydraulic telescopic rod housing (2-2), the bottom of the hydraulic telescopic rod housing (2-2) is connected to the telescopic support rotating support (2-3), and the hydraulic telescopic rod housing (2-2) can be telescopically supported and rotated with the center of the hole of the rotating support as the axis, and the top of the hydraulic telescopic rod (2-1) can slide in the supporting slide groove (1-4) but does not separate; the supporting rotating support (2-3) is fixedly connected to the spherical node (2-4), the bottom of the spherical node (2-4) is fixedly connected to the force measuring connecting rod (2-5), the bottom of the force measuring connecting rod is fixedly connected to the disc limit (2-6), the lower end of the connecting spring (2-7) is fixedly connected to the spherical node (2-4), and the upper end is fixedly connected to the center of the upper turbojet engine mounting platform (1).

[0012] The technical solution is further optimized, and the bottom hemispherical support (3) includes a hemispherical support (3-1), a hollow cylindrical force measuring limiter (3-2), a vertical diagonal brace (3-3) and a plane diagonal brace (3-4); the corner of the plane diagonal brace (3-4) is fixedly connected to the bottom of the vertical diagonal brace (3-3), and the top of the vertical diagonal brace (3-3) is fixedly connected to the hemispherical support (3-1); the interior of the hemispherical support (3-1) is a cavity, and the diameter of the cavity is equal to the diameter of the spherical node (2-4); the diameter of the force measuring connecting rod (2-5) is equal to the diameter of the through hole (2-4). The holes (3-1A) have equal diameters, the force measuring connecting rod (2-5) penetrates along the central axis of the through hole (3-1A), the diameter of the disc limiter (2-6) is equal to the inner diameter of the hollow cylindrical force measuring limiter (3-2), and the central telescopic support and the spherical node (2) are restricted from swinging. The disc limiter (2-6) can slide inside the hollow cylindrical force measuring limiter (3-2), a pressure sensor is installed on the disc limiter (2-6), and a cylindrical compression spring is arranged between the disc limiter (2-6) and the hemispherical support (3-1) along the force measuring connecting rod (2-5).

[0013] This technical solution is further optimized in that a through hole (3-1A) is provided at the axis of the hemispherical support (3-1).

[0014] A method for adjusting parameters of an aircraft balance parameter adjustment test bench comprises the following steps:

[0015] S61, adjusting the telescopic inner rod (1-2) and the telescopic outer rod (1-3) to change the position of the turbojet engine mounting ring (1-1) to adapt to aircraft of different sizes; after the adjustment is completed, locking the telescopic inner rod (1-2) and the telescopic outer rod (1-3), that is, the relative position of the telescopic inner rod (1-2) and the telescopic outer rod (1-3) is fixed;

[0016] S62, a stepped turbojet engine oiling method, wherein the oiling amount changed each time is 5% of the maximum oiling amount of the turbojet engine, and the hydraulic telescopic rod (2-1) is in a free state during the oiling amount change process, that is, the relative position of the hydraulic telescopic rod (2-1) and the hydraulic telescopic rod housing (2-2) is variable, and the angle of the telescopic support rotating support (2-3) is variable. The length of the hydraulic telescopic rod (2-1) and the angle of the telescopic support rotating support (2-3) are recorded in real time. When the length of the hydraulic telescopic rod (2-1) is outside the range of 10% to 90% of the maximum length and the position of the telescopic support rotating support (2-3) is outside the range of 10% to 90% of the maximum angle, the system alarms and simultaneously outputs the total lift and thrust of each turbojet engine at this time for debugging;

[0017] S63, the upper turbojet engine mounting platform (1) is stable. Due to the different thrusts of the four turbojet engines, pitch angles and roll angles appear, and the hydraulic telescopic rod (2-1) is in a locked state, that is, the relative positions of the hydraulic telescopic rod (2-1) and the hydraulic telescopic rod housing (2-2) are fixed, and the angle of the telescopic support rotating support (2-3) is fixed;

[0018] S64, upper turbojet engine mounting platform (1) attitude determination, adjustment methods are divided into:

[0019] 5) When the telescopic support rotating support (2-3) is located outside the range of 10% to 90% of the maximum angle, the hydraulic telescopic rod (2-1) above the center of the upper turbojet engine mounting platform (1) is reduced in length, and the hydraulic telescopic rod (2-1) below the center of the upper turbojet engine mounting platform (1) is increased in length;

[0020] 6) When the length of the hydraulic telescopic rod (2-1) is outside the range of 10% to 90% of the maximum length, the telescopic support rotating support (2-3) above the center of the upper turbojet engine mounting platform (1) rotates outward, and the telescopic support rotating support (2-3) below the center of the upper turbojet engine mounting platform (1) rotates inward;

[0021] 7) When the position of the telescopic support rotating support (2-3) is within the range of 10% to 90% of the maximum angle and the length of the hydraulic telescopic rod (2-1) is within the range of 10% to 90% of the maximum length, the hydraulic telescopic rod (2-1) above the center of the upper turbojet engine mounting platform (1) is reduced in length, and the telescopic support rotating support (2-3) is rotated outwardly, while the hydraulic telescopic rod (2-1) below the center of the upper turbojet engine mounting platform (1) is increased in length, and the telescopic support rotating support (2-3) is rotated inwardly;

[0022] 8) When the position of the telescopic support rotating support (2-3) is outside the range of 10% to 90% of the maximum angle, and the length of the hydraulic telescopic rod (2-1) is outside the range of 10% to 90% of the maximum length, the system alarms and simultaneously outputs the total lift and thrust of each turbojet engine at this time for debugging;

[0023] S65. Using a BP neural network to adjust in real time the proportional adjustment coefficient, differential adjustment coefficient, and integral adjustment coefficient of the PID controller for controlling the length of the hydraulic telescopic rod (2-1) and the PID controller for controlling the angle of the telescopic support and rotating support (2-3), so that they can adapt to the control requirements of the aircraft under different circumstances. During the adjustment process, a balance strategy of exploration and exploitation can be adopted. By trying and evaluating different parameter combinations, the performance of the length control PID controller and the angle control PID controller can be gradually optimized.

[0024] S66, after the attitude adjustment is completed, the hydraulic telescopic rod (2-1) is released to be in a free state, the fuel supply to the turbojet engine is increased, and S62 to S65 are repeated until the maximum fuel supply is achieved;

[0025] S67. After the maximum fuel injection attitude adjustment is completed, the test is completed, and the relationship between the fuel injection and the total lift, the fuel injection and the thrust of each turbojet engine, as well as the proportional adjustment coefficient, differential adjustment coefficient and integral adjustment coefficient of the angle control and length control PID controllers are obtained. The relationship between the fuel injection and the total lift, and the fuel injection and the thrust of each turbojet engine can be used to determine whether the parameters of the angle control and length control PID controllers are optimal. The proportional adjustment coefficient, differential adjustment coefficient and integral adjustment coefficient of the angle control and length control PID controllers can be calculated to obtain the proportional adjustment coefficient, differential adjustment coefficient and integral adjustment coefficient of the turbojet engine control PID controller.

[0026] The technical solution is further optimized, and the calculation method of total lift and thrust of each turbojet engine is as follows:

[0027] The position motion equation of the UAV is:

[0028]

[0029] Among them, m represents the mass of the drone, and [xyz] T They represent the net external force acting on the UAV and the center of mass position of the quadrotor UAV respectively;

[0030] During the test of the upper turbojet engine mounting platform (1), it can be seen from the force analysis that the external force mainly includes the lift generated by the turbojet and its own gravity, so the total external force F on the upper turbojet engine mounting platform (1) is p for:

[0031]

[0032] in, represents the lift generated by the turbojet engine in the coordinate system of the upper turbojet engine mounting platform (1), represents the weight of the upper turbojet engine mounting platform (1) itself in the inertial coordinate system, Indicates the pulling force exerted by the middle telescopic support and spherical node (2) on the upper turbojet engine mounting platform (1) through the hydraulic telescopic rod (2-1) in the inertial coordinate system. represents the pulling force exerted by the connecting spring (2-7) on the upper turbojet engine mounting platform (1) in the inertial coordinate system;

[0033] It can be described as the superposition of the lift generated by four turbojet engines, then:

[0034]

[0035] The weight of the upper turbojet engine mounting platform (1) itself It can be described as:

[0036]

[0037] where m p represents the mass of the upper turbojet engine mounting platform (1), g represents the gravity coefficient of the earth's gravity;

[0038] The tension of the connecting spring (2-7) on the upper turbojet engine mounting platform (1) It can be described as:

[0039]

[0040] Among them F t Indicates the elastic force of the connecting spring (2-7);

[0041] After adjustment, the upper turbojet engine mounting platform (1) is in a force-balanced state, at which point:

[0042] F p =0

[0043] Based on the above analysis, it can be seen that the pulling force exerted by the middle telescopic support and the spherical node (2) on the upper turbojet engine mounting platform (1) is for:

[0044]

[0045] Wherein, θ, φ and ψ represent the pitch angle, roll angle and yaw angle of the upper turbojet engine mounting platform (1), respectively; represents the resultant force produced by four turbojet engines;

[0046] The vertical total external force on the spherical node (2-4) for:

[0047]

[0048] in, represents the gravity of the middle telescopic support and the spherical node (2) in the inertial coordinate system, Indicates the reaction force on the disk limiter (2-6) in the inertial coordinate system, the gravity of the central telescopic support and the spherical node (2) itself It can be expressed as:

[0049]

[0050] Reaction force on the disc limiter (2-6) is the value of the pressure sensor;

[0051] Based on the above analysis, we can know that:

[0052]

[0053] Among them, α i is the angle between the telescopic outer rod (1-3) and the horizontal plane, F i s is the pulling force exerted by a single telescopic inner rod (1-2) on the upper turbojet engine mounting platform (1), then the lift generated by the four turbojet engines can be described as:

[0054]

[0055] The force analysis of the single upper turbojet engine mounting platform (1) shows:

[0056]

[0057] Among them, M p is the bending moment in the middle of the single upper turbojet engine mounting platform (1), D i is the distance from the center of the upper turbojet engine mounting platform (1) to the center of the turbojet engine mounting ring (1-1), β i is the angle between the telescopic inner rod (1-2) and the plane of the upper turbojet engine mounting platform (1), and β i =f(θ,φ,α i ), The distance from the center of the upper turbojet engine mounting platform (1) to the action point of the hydraulic telescopic rod (2-1);

[0058] Based on the above theoretical analysis, the thrust of each turbojet engine can be described as:

[0059]

[0060] The technical solution is further optimized, the PID parameters include angle control PID parameters, length control PID parameters and turbojet engine control PID parameters, angle control output:

[0061]

[0062] in, is the angle proportional adjustment coefficient, is the angle integral adjustment coefficient, is the angle differential adjustment coefficient; u α (k) is the kth angle control output, e α (k) is the angle error value calculated for the kth time, e α (j) is the angle error value calculated for the jth time, e α (k-1) is the angle error value calculated for the k-1th time;

[0063] Length control output:

[0064]

[0065] in, is the length ratio adjustment coefficient, is the length integral adjustment coefficient, is the length differential adjustment coefficient; u l (k) is the k-th length control output, e l (k) is the length error value calculated for the kth time, e l (j) is the length error value calculated for the jth time, e l (k-1) is the length error value calculated for the k-1th time;

[0066] Turbojet engine control output:

[0067]

[0068] in, is the turbojet engine proportional adjustment coefficient, is the integral adjustment coefficient of the turbojet engine, is the differential adjustment coefficient of the turbojet engine; u b (k) is the kth turbojet engine control output, e b (k) is the error value of the turbojet engine calculated for the kth time, e b (j) is the length error value calculated for the jth time, e b (k-1) is the error value of the turbojet engine calculated for the k-1th time;

[0069] When the angle error value e α When the engine is relatively small, the error value e of the turbojet engine is b It can be expressed as:

[0070] e b =R·(le α +e l )

[0071] Wherein, R is a coefficient determined by the average distance from the center of the upper turbojet engine mounting platform (1) to the center of the turbojet engine mounting ring (1-1), and the average distance from the center of the upper turbojet engine mounting platform (1) to the action point of the hydraulic telescopic rod (2-1), and l is the length of the connecting spring (2-7);

[0072] Similarly, the turbojet engine control output u b (k) can be expressed as:

[0073] u b (k)=Au α (k)+Bu l (k)

[0074] Among them, A and B are coefficients;

[0075] Based on the above theoretical analysis, it can be seen that the turbojet engine proportional adjustment coefficient Turbojet engine integral adjustment coefficient Turbojet engine differential adjustment coefficient It can be described as:

[0076]

[0077] Further optimization of this technical solution, using BP neural network to adjust PID parameters includes the following steps:

[0078] S91, Data acquisition and preprocessing: Collect input and output data of the aircraft balance parameter adjustment test bench and preprocess the data;

[0079] S92. BP neural network model design and training: Establish a BP neural network model and use the collected pre-processed data to train the BP neural network using the back propagation algorithm;

[0080] S93, PID controller design: Based on BP neural network, design angle control and length control PID controllers;

[0081] S94, real-time control and feedback adjustment: Combine the trained BP neural network with the angle control and length control PID controllers and apply them to the test bench system. By collecting sensor data in real time, calculating control signals and controlling actuators, the real-time control of the test bench system and the optimization of the angle control and length control PID controller parameters are achieved.

[0082] Different from the existing technology, the above technical solution has the following beneficial effects:

[0083] (1) This aircraft balance parameter adjustment test bench includes an upper turbojet engine mounting platform, a middle telescopic support and spherical node, and a bottom hemispherical support. Its structural layout is simple, which can overcome the shortcomings of existing test benches that require single parameter adjustment and multiple tests.

[0084] (2) The upper turbojet engine mounting platform adjusts the relative positions of the four turbojet engines by changing the relative positions of the telescopic inner rod and the telescopic outer rod to adapt to different aircraft specifications. In the case of uncertain aircraft specifications, the optimal aircraft specifications can be determined through experiments;

[0085] (3) The central telescopic support and spherical node are always connected to the upper turbojet engine mounting platform. When a large-scale tilt occurs during the test, an alarm is triggered to prevent overturning, thereby improving the safety of the test bench.

[0086] (4) By changing the length and angle of the hydraulic telescopic rod, the platform level is adjusted, avoiding the complicated operation of directly adjusting the turbojet engine control PID parameters. The length control PID parameters and angle control PID parameters of the hydraulic telescopic rod are continuously optimized during the test. The total lift and thrust of each turbojet engine are recorded in real time during the leveling process, providing a basis for judging whether the PID parameters are optimal, thus achieving a single test and multiple parameter adjustments.

[0087] (5) The hemispherical support at the bottom limits the flight altitude, and its configuration design ensures that the test bench can withstand the dynamic load during the test, which is safe and reliable. The present invention provides technical support for the flight control debugging test of turbojet engine aircraft, especially the PID control debugging test. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] Figure 1 A schematic structural diagram of an aircraft balance parameter adjustment test bench provided by the present invention;

[0089] Figure 2 This is a schematic structural diagram of the upper turbojet engine mounting platform of the present invention;

[0090] Figure 3 This is a schematic diagram of the central telescopic support and spherical node structure of the present invention;

[0091] Figure 4This is a schematic diagram of the bottom hemispherical support structure of the present invention;

[0092] Figure 5 Flowchart of the parameter adjustment method provided by the present invention;

[0093] Figure 6 This is a force analysis diagram of the upper turbojet engine mounting platform of the present invention;

[0094] Figure 7 This is a force analysis diagram of the middle telescopic support and spherical node of the present invention;

[0095] Figure 8 This is a force analysis diagram of the single upper turbojet engine mounting platform of the present invention. DETAILED DESCRIPTION

[0096] In order to explain the technical content, structural features, achieved objectives and effects of the technical solution in detail, the following is a detailed description in conjunction with specific embodiments and accompanying drawings.

[0097] See Figure 1 FIG2 is a schematic diagram of the structure of an aircraft balance parameter adjustment test bench according to a preferred embodiment of the present invention. The test bench comprises an upper turbojet engine mounting platform 1, a middle telescopic support and spherical node 2, and a bottom hemispherical support 3.

[0098] according to Figure 2 As shown, the upper turbojet engine mounting platform 1 includes a turbojet engine mounting ring 1-1, a telescopic inner rod 1-2, a telescopic outer rod 1-3, and a support chute 1-4. The turbojet engine mounting ring 1-1 is a hollow circular ring with an outer diameter AD1 of 260 mm and an outer diameter AD2 of 230 mm. The ring specifications can be manufactured according to the specifications of the turbojet engine. The turbojet engine mounting ring 1-1 is fixedly connected to the telescopic inner rod 1-2. The telescopic inner rod 1-2 can slide within the telescopic outer rod 1-3. The sliding length ΔAL is the length of the telescopic inner rod 1-2 extending from the telescopic outer rod 1-3, and the range of ΔAL∈[50 mm, 500 mm] is used to adjust the position of the turbojet engine mounting ring 1-1 to meet the dimensional requirements required for testing. The relative position of the telescopic outer rod 1-3 and the telescopic inner rod 1-2 can be fixed and locked. Each telescopic outer rod has a length AL1 of 500mm, a width AB1 of 40mm, and a height AH1 of 50mm. Each telescopic inner rod has a length AL2 of 550mm, a width AB2 of 30mm, and a height AH2 of 15mm. Support chutes 1-4 are located midway along telescopic outer rods 1-3. They have a length AL3 of 300mm, a width AB3 of 30mm, and a depth AH3 of 30mm.

[0099] according to Figure 3As shown, the central telescopic support and spherical node 2 includes a hydraulic telescopic rod 2-1, a hydraulic telescopic rod housing 2-2, a telescopic support rotating support 2-3, a spherical node 2-4, a force-measuring link 2-5, a disc limiter 2-6, and a connecting spring 2-7. The hydraulic telescopic rod 2-1 can slide within the hydraulic telescopic rod housing 2-2. The hydraulic telescopic rod has a diameter BD1 of 30 mm and a rounded top with the same diameter as BD1. The top of the hydraulic telescopic rod 2-1 can slide within the support chute 1-4 without disengaging. The hydraulic telescopic rod housing 2-2 has a diameter of 40 mm and a length BL1 of 200 mm. The bottom of the hydraulic telescopic rod housing 2-2 is connected to the telescopic support rotating support 2-3. The hydraulic telescopic rod housing 2-2 can rotate about the center of the opening of the telescopic support rotating support within a rotation range of Δα∈[30°, 90°], where α is the angle between the telescopic support and the horizontal plane. The telescopic support rotating bearing 2-3 is fixedly connected to the spherical node 2-4, the diameter BD2 of the spherical node 2-4 is 120mm, the bottom of the spherical node 2-4 is fixedly connected to the force-measuring link 2-5, the diameter BD3 of the force-measuring link 2-5 is 15mm, and the length BL3 is 150mm. The bottom of the force-measuring link 2-5 is fixedly connected to the disc limit 2-6, the force-measuring link 2-5 is concentric with the disc limit 2-6, the diameter BD4 of the disc limit 2-6 is 50mm, and the thickness BH4 is 10mm. The lower end of the connecting spring 2-7 is fixedly connected to the spherical node 2-4, and the upper end is fixedly connected to the center of the upper turbojet engine mounting platform 1. The connecting spring 2-7 is a cylindrical tension spring.

[0100] according to Figure 4 As shown, the bottom hemispherical support 3 includes a hemispherical support 3-1, a hollow cylindrical force measuring limit 3-2, a vertical diagonal brace 3-3 and a plane diagonal brace 3-4, wherein a through hole 3-1A is provided at the axis of the hemispherical support 3-1. The corner of the plane diagonal brace 3-4 is fixedly connected to the bottom of the vertical diagonal brace 3-3, and the top of the vertical diagonal brace 3-3 is fixedly connected to the hemispherical support 3-1. The plane diagonal brace 3-4 and the vertical diagonal brace 3-3 are both hollow square steel tubes with a rectangular cross-section, a length CL1 of 30mm, a width CB1 of 30mm, and a wall thickness Ch1 of 2mm. The interior of the hemispherical support 3-1 is a cavity, the diameter of the cavity is equal to the diameter BD2 of the spherical node 2-4, and the wall thickness Ch2 of the hemispherical support 3-1 is 2mm; the diameter of the through hole 3-1A is equal to the diameter of the force measuring connecting rod 2-5 The diameters BD3 are equal, the force measuring link 2-5 penetrates along the central axis of the through hole 3-1A, the inner diameter of the hollow cylindrical force measuring limit 3-2 is equal to the diameter BD4 of the disc limit 2-6, the wall thickness Ch3 of the hollow cylindrical force measuring limit 2-6 is 2mm, which limits the swing of the middle telescopic support and the spherical node 2, and the disc limit 2-6 can slide inside the hollow cylindrical force measuring limit 3-2. A pressure sensor is installed on the disc limit 2-6, and a cylindrical compression spring is set along the force measuring link 2-5 between the disc limit 2-6 and the hemispherical support 3-1.

[0101] Figure 5 Flowchart of the parameter adjustment method according to a preferred embodiment of the present invention. The parameter adjustment method of the present invention comprises the following steps:

[0102] S1. Adjust and install the turbojet engine: Install the turbojet engine in the turbojet engine mounting ring 1-1, with the turbojet thrust direction being vertical and the turbojet engine mounting ring 1-1 vertically upward. Adjust the length ΔAL of the telescopic inner rod 1-2 extending from the telescopic outer rod 1-3. For example, the length ΔAL of the telescopic inner rod 1-2 extending from the telescopic outer rod 1-3 is adjusted to 400 mm and locked, that is, the relative positions of the telescopic inner rod 1-2 and the telescopic outer rod 1-3 do not change.

[0103] S2. Step-by-step oil supply: The initial oil supply is 20% of the maximum oil supply. At this time, the hydraulic telescopic rod is in a free state, that is, the length and angle of the hydraulic telescopic rod will change with the pitch angle or roll angle of the upper turbojet engine mounting platform 1. Due to the action of the connecting springs 2-7, the upper turbojet engine mounting platform 1 will not rise significantly.

[0104] S3. Upper turbojet engine mounting platform is stable: After a certain period of time, the upper turbojet engine mounting platform 1 remains stable, and the pitch angle or roll angle is not zero.

[0105] S4. Attitude determination and adjustment of the length and angle of the hydraulic telescopic rod: The length and angle of the hydraulic telescopic rod are locked. The length control PID controller and the angle control PID controller are controlled simultaneously to restore the pitch angle and roll angle to keep the upper turbojet engine mounting platform 1 level. The basic adjustment rules are as follows:

[0106] 1) When the telescopic support rotating support 2-3 is located outside the range of 10% to 90% of the maximum angle: the hydraulic telescopic rod 2-1 above the center of the upper turbojet engine mounting platform 1 is reduced in length, and the hydraulic telescopic rod 2-1 below the center of the upper turbojet engine mounting platform 1 is increased in length;

[0107] 2) When the length of the hydraulic telescopic rod 2-1 is outside the range of 10% to 90% of the maximum length: the telescopic support rotating support 2-3 above the center of the upper turbojet engine mounting platform 1 rotates outward, and the telescopic support rotating support 2-3 below the center of the upper turbojet engine mounting platform 1 rotates inward;

[0108] 3) When the position of the telescopic support rotating support 2-3 is within the range of 10% to 90% of the maximum angle, and the length of the hydraulic telescopic rod 2-1 is within the range of 10% to 90% of the maximum length: the hydraulic telescopic rod 2-1 above the center of the upper turbojet engine mounting platform 1 is reduced in length, and the telescopic support rotating support 2-3 is rotated outwardly; the hydraulic telescopic rod 2-1 below the center of the upper turbojet engine mounting platform 1 is increased in length, and the telescopic support rotating support 2-3 is rotated inwardly;

[0109] 4) When the position of the telescopic support rotating support 2-3 is outside the range of 10% to 90% of the maximum angle, and the length of the hydraulic telescopic rod 2-1 is outside the range of 10% to 90% of the maximum length: the system alarms and outputs the total lift and thrust of each turbojet engine at this time for debugging.

[0110] S5. Optimize the parameters of the length control and angle control PID controllers using the BP neural network: The length control and angle control PID controllers will be updated each time they are calculated.

[0111] S6. Increase the fuel supply to the turbojet engine: After a single adjustment is completed, release the hydraulic telescopic rod to increase the fuel supply by 5% of the maximum fuel supply. After the upper turbojet engine mounting platform 1 is stable, repeat the parameter adjustment until the fuel supply reaches the maximum value.

[0112] S7. Calculate the turbojet engine PID parameters: Optimize the length control and angle control PID controller parameters through the BP neural network, and output the proportional adjustment coefficient, integral adjustment coefficient, and differential adjustment coefficient of the hydraulic telescopic rod length control PID controller and the proportional adjustment coefficient, integral adjustment coefficient, and differential adjustment coefficient of the hydraulic telescopic rod angle control PID controller using the formula:

[0113]

[0114] The proportional adjustment coefficient, integral adjustment coefficient, and differential adjustment coefficient of the turbojet engine control PID controller can be obtained. is the turbojet engine proportional adjustment coefficient, is the integral adjustment coefficient of the turbojet engine, is the differential adjustment coefficient of the turbojet engine, is the angle proportional adjustment coefficient, is the angle integral adjustment coefficient, is the angle differential adjustment coefficient, is the length ratio adjustment coefficient, is the length integral adjustment coefficient, is the length differential adjustment coefficient. The relationship between fuel supply and total lift, and between fuel supply and thrust of each turbojet are also output to facilitate multiple tests to obtain the optimal PID controller parameters.

[0115] This embodiment preferably provides an aircraft balance parameter adjustment test bench and a parameter adjustment method thereof, the parameter adjustment method comprising the following steps:

[0116] S1. Adjust the telescopic inner rod (1-2) and the telescopic outer rod (1-3) to change the position of the turbojet engine mounting ring (1-1) to adapt to aircraft of different sizes. After the adjustment is completed, the telescopic inner rod (1-2) and the telescopic outer rod (1-3) are locked, that is, the relative position of the telescopic inner rod (1-2) and the telescopic outer rod (1-3) is fixed.

[0117] S2, a stepped turbojet engine oiling method, wherein the oiling amount is changed by 5% of the maximum oiling amount of the turbojet engine each time, and the hydraulic telescopic rod (2-1) is in a free state during the oiling amount change process, that is, the relative position of the hydraulic telescopic rod (2-1) and the hydraulic telescopic rod housing (2-2) is variable, and the angle of the telescopic support rotating support (2-3) is variable. The length of the hydraulic telescopic rod (2-1) and the angle of the telescopic support rotating support (2-3) are recorded in real time. When the length of the hydraulic telescopic rod (2-1) is outside the range of 10% to 90% of the maximum length and the position of the telescopic support rotating support (2-3) is outside the range of 10% to 90% of the maximum angle, the system alarms and simultaneously outputs the total lift and thrust of each turbojet engine at this time for debugging;

[0118] S3. The upper turbojet engine mounting platform (1) is stable. Due to the different thrusts of the four turbojet engines, pitch angles and roll angles appear. The hydraulic telescopic rod (2-1) is in a locked state, that is, the relative positions of the hydraulic telescopic rod (2-1) and the hydraulic telescopic rod housing (2-2) are fixed, and the angle of the telescopic support rotating support (2-3) is fixed.

[0119] S4. Attitude determination of the upper turbojet engine mounting platform (1). The adjustment methods are as follows:

[0120] 1) When the telescopic support rotating support (2-3) is located outside the range of 10% to 90% of the maximum angle, the hydraulic telescopic rod (2-1) above the center of the upper turbojet engine mounting platform (1) is reduced in length, and the hydraulic telescopic rod (2-1) below the center of the upper turbojet engine mounting platform (1) is increased in length;

[0121] 2) When the length of the hydraulic telescopic rod (2-1) is outside the range of 10% to 90% of the maximum length, the telescopic support rotating support (2-3) above the center of the upper turbojet engine mounting platform (1) rotates outward, and the telescopic support rotating support (2-3) below the center of the upper turbojet engine mounting platform (1) rotates inward;

[0122] 3) When the position of the telescopic support rotating support (2-3) is within the range of 10% to 90% of the maximum angle and the length of the hydraulic telescopic rod (2-1) is within the range of 10% to 90% of the maximum length, the hydraulic telescopic rod (2-1) above the center of the upper turbojet engine mounting platform (1) is reduced in length, and the telescopic support rotating support (2-3) is rotated outwardly, while the hydraulic telescopic rod (2-1) below the center of the upper turbojet engine mounting platform (1) is increased in length, and the telescopic support rotating support (2-3) is rotated inwardly;

[0123] 4) When the position of the telescopic support rotating support (2-3) is outside the range of 10% to 90% of the maximum angle, and the length of the hydraulic telescopic rod (2-1) is outside the range of 10% to 90% of the maximum length, the system alarms and simultaneously outputs the total lift and thrust of each turbojet engine at this time for debugging.

[0124] S5. Utilize a BP neural network to adjust the proportional, differential, and integral control coefficients of the angle and length control PID controllers in real time, enabling them to adapt to the aircraft's control requirements under different circumstances. During this adjustment process, a balanced strategy of exploration and exploitation can be employed, gradually optimizing controller performance by experimenting with and evaluating different parameter combinations.

[0125] S6. After the attitude adjustment is completed, the hydraulic telescopic rod (2-1) is released to be in a free state, thereby increasing the fuel supply to the turbojet engine and repeating S2 to S5.

[0126] S7. After the maximum fuel injection attitude adjustment is completed, the test is completed, and the relationship between the fuel injection and the total lift of the four turbojet engines, the fuel injection and the thrust of each turbojet engine, as well as the proportional adjustment coefficient, differential adjustment coefficient and integral adjustment coefficient of the angle control and length control PID controllers are obtained. The relationship between the fuel injection and the total lift, and the fuel injection and the thrust of each turbojet engine can be used to determine whether the parameters of the angle control and length control PID controllers are optimal. The proportional adjustment coefficient, differential adjustment coefficient and integral adjustment coefficient of the angle control and length control PID controllers can be calculated to obtain the proportional adjustment coefficient, differential adjustment coefficient and integral adjustment coefficient of the turbojet engine control PID controller.

[0127] The position motion equation of the UAV is:

[0128]

[0129] Among them, m represents the mass of the drone, and [xyz] T They represent the net external force acting on the UAV and the center of mass position of the quadrotor UAV respectively.

[0130] During the test of the upper turbojet engine mounting platform (1), it can be seen from the force analysis that the external force mainly includes the lift generated by the turbojet and its own gravity, so the total external force F on the upper turbojet engine mounting platform (1) is p for:

[0131]

[0132] in, represents the lift generated by the turbojet engine in the coordinate system of the upper turbojet engine mounting platform (1), represents the weight of the upper turbojet engine mounting platform (1) itself in the inertial coordinate system, Indicates the pulling force exerted by the middle telescopic support and spherical node (2) on the upper turbojet engine mounting platform (1) through the hydraulic telescopic rod (2-1) in the inertial coordinate system. It represents the pulling force exerted by the connecting spring (2-7) on the upper turbojet engine mounting platform (1) in the inertial coordinate system.

[0133] It can be described as the superposition of the lift generated by four turbojet engines, then:

[0134]

[0135] The weight of the upper turbojet engine mounting platform (1) itself It can be described as:

[0136]

[0137] where m p represents the mass of the upper turbojet engine mounting platform (1), and g represents the gravity coefficient of the earth's gravity.

[0138] The tension of the connecting spring (2-7) on the upper turbojet engine mounting platform (1) It can be described as:

[0139]

[0140] Among them F t Indicates the elastic force of the connecting spring (2-7).

[0141] After adjustment, the upper turbojet engine mounting platform (1) is in a force-balanced state, at which point:

[0142] F p =0

[0143] Based on the above analysis, it can be seen that the pulling force exerted by the middle telescopic support and the spherical node (2) on the upper turbojet engine mounting platform (1) is for:

[0144]

[0145] Wherein, θ, φ and ψ represent the pitch angle, roll angle and yaw angle of the upper turbojet engine mounting platform (1), respectively; Represents the resultant force generated by four turbojet engines.

[0146] The vertical total external force on the spherical node (2-4) for:

[0147]

[0148] in, represents the gravity of the middle telescopic support and the spherical node (2) in the inertial coordinate system, The reaction force on the disc limiter (2-6) in the inertial coordinate system. The gravity of the central telescopic support and the spherical node (2) itself It can be expressed as:

[0149]

[0150] Reaction force on the disc limiter (2-6) is the value of the pressure sensor.

[0151] Based on the above analysis, we can know that:

[0152]

[0153] Among them, α i is the angle between the telescopic outer rod (1-3) and the horizontal plane, F i s The lift generated by the four turbojet engines can be described as follows:

[0154]

[0155] The force analysis of the single upper turbojet engine mounting platform (1) yields:

[0156]

[0157] Among them, M p is the bending moment in the middle of the single upper turbojet engine mounting platform (1), D i is the distance from the center of the upper turbojet engine mounting platform (1) to the center of the turbojet engine mounting ring (1-1), β i is the angle between the telescopic inner rod (1-2) and the plane of the upper turbojet engine mounting platform (1), and β i =f(θ,φ,α i ), It is the distance from the center of the upper turbojet engine mounting platform (1) to the action point of the hydraulic telescopic rod (2-1).

[0158] Based on the above theoretical analysis, the thrust of each turbojet engine can be described as:

[0159]

[0160] PID parameters include angle control PID parameters, length control PID parameters and turbojet engine control PID parameters. Angle control output:

[0161]

[0162] in, is the angle proportional adjustment coefficient, is the angle integral adjustment coefficient, is the angle differential adjustment coefficient; u α (k) is the kth angle control output, e α (k) is the angle error value calculated for the kth time, e α (j) is the angle error value calculated for the jth time, e α (k-1) is the angle error value calculated for the k-1th time;

[0163] Length control output:

[0164]

[0165] in, is the length ratio adjustment coefficient, is the length integral adjustment coefficient, is the length differential adjustment coefficient; u l (k) is the k-th length control output, e l (k) is the length error value calculated for the kth time, e l (j) is the length error value calculated for the jth time, e l (k-1) is the length error value calculated for the k-1th time;

[0166] Turbojet engine control output:

[0167]

[0168] in, is the turbojet engine proportional adjustment coefficient, is the integral adjustment coefficient of the turbojet engine, is the differential adjustment coefficient of the turbojet engine; u b (k) is the kth turbojet engine control output, e b(k) is the error value of the turbojet engine calculated for the kth time, e b (j) is the length error value calculated for the jth time, e b (k-1) is the error value of the turbojet engine calculated for the k-1th time;

[0169] When the angle error value e α When the engine is relatively small, the error value e of the turbojet engine is b It can be expressed as:

[0170] e b =R·(le α +e l )

[0171] Wherein, R is a coefficient determined by the average distance from the center of the upper turbojet engine mounting platform (1) to the center of the turbojet engine mounting ring (1-1), and the average distance from the center of the upper turbojet engine mounting platform (1) to the action point of the hydraulic telescopic rod (2-1), and l is the length of the connecting spring (2-7).

[0172] Similarly, the turbojet engine control output u b (k) can be expressed as:

[0173] u b (k)=Au α (k)+Bu l (k)

[0174] Among them, A and B are coefficients.

[0175] Based on the above theoretical analysis, it can be seen that the turbojet engine proportional adjustment coefficient Turbojet engine integral adjustment coefficient Turbojet engine differential adjustment coefficient It can be described as:

[0176]

[0177] Adjusting PID parameters using BP neural network includes the following steps:

[0178] S1. Data acquisition and preprocessing: Collect input and output data of the aircraft balance parameter adjustment test bench and preprocess the data;

[0179] S2. BP neural network model design and training: Establish a BP neural network model, use the collected pre-processed data, and use the back propagation algorithm to train the BP neural network;

[0180] S3. PID controller design: Based on the BP neural network, design the angle control and length control PID controllers;

[0181] S4. Real-time control and feedback adjustment: Combine the trained BP neural network and PID controller and apply them to the test bench system. By collecting sensor data in real time, calculating control signals and controlling actuators, real-time control of the test bench system and optimization of the angle control and length control PID controller parameters are achieved.

[0182] It should be noted that, in this document, relational terms such as first and second, etc., are used solely to distinguish one entity or operation from another, and do not necessarily require or imply any actual relationship or order between these entities or operations. Furthermore, the terms "include," "comprise," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or terminal device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or terminal device. Without further limitation, elements defined by the phrase "include..." or "comprising..." do not exclude the presence of additional elements in the process, method, article, or terminal device comprising the elements. Furthermore, in this document, "greater than," "less than," "exceeding," etc., are understood to exclude the number itself; "above," "below," "within," etc., are understood to include the number itself.

[0183] Although the above embodiments have been described, those skilled in the art may make additional changes and modifications to these embodiments once they know the basic creative concepts. Therefore, the above descriptions are merely embodiments of the present invention and do not limit the scope of patent protection of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the scope of patent protection of the present invention.

Claims

1. An aircraft balance parameter adjustment test bench, characterized by: It comprises an upper turbojet engine mounting platform (1), a middle telescopic support and spherical node (2), and a bottom hemispherical support (3); The upper turbojet engine mounting platform (1) is elastically connected to the middle telescopic support and spherical node (2) via a connecting spring (2-7), and is slidably connected to the support chute (1-4) via a hydraulic telescopic rod (2-1); the middle telescopic support and spherical node (2) is slidably connected to the bottom hemispherical support (3) via a disc limiter (2-6) and a hollow cylindrical force measuring limiter (3-2); The middle telescopic support and spherical node (2) comprises a hydraulic telescopic rod (2-1), a hydraulic telescopic rod housing (2-2), a telescopic support rotating support (2-3), a spherical node (2-4), a force measuring connecting rod (2-5), a disc limiter (2-6) and a connecting spring (2-7); the hydraulic telescopic rod (2-1) can slide in the hydraulic telescopic rod housing (2-2), the bottom of the hydraulic telescopic rod housing (2-2) is connected to the telescopic support rotating support (2-3), and the hydraulic telescopic rod housing (2-2) can be The top of the hydraulic telescopic rod (2-1) can slide in the support groove (1-4) but does not separate when the center of the opening of the telescopic support rotating support is used as the axis of rotation; the support rotating support (2-3) is fixedly connected to the spherical node (2-4); the bottom of the spherical node (2-4) is fixedly connected to the force measuring connecting rod (2-5); the bottom of the force measuring connecting rod is fixedly connected to the disc limiter (2-6); the lower end of the connecting spring (2-7) is fixedly connected to the spherical node (2-4); and the upper end is fixedly connected to the center of the upper turbojet engine mounting platform (1).

2. The aircraft balance parameter adjustment test bench according to claim 1, characterized in that: The upper turbojet engine mounting platform (1) comprises a turbojet engine mounting ring (1-1), a telescopic inner rod (1-2), a telescopic outer rod (1-3) and a supporting slide groove (1-4); the turbojet engine mounting ring (1-1) is fixedly connected to the telescopic inner rod (1-2); the telescopic inner rod (1-2) can slide in the telescopic outer rod (1-3), thereby adjusting the position of the engine mounting ring (1-1) to achieve the size requirements required for testing; and the relative position of the telescopic outer rod (1-3) and the telescopic inner rod (1-2) can be fixed.

3. The aircraft balance parameter adjustment test bench according to claim 1, characterized in that: The bottom hemispherical support (3) comprises a hemispherical support (3-1), a hollow cylindrical force measuring limiter (3-2), a vertical diagonal brace (3-3) and a plane diagonal brace (3-4); the corner of the plane diagonal brace (3-4) is fixedly connected to the bottom of the vertical diagonal brace (3-3), and the top of the vertical diagonal brace (3-3) is fixedly connected to the hemispherical support (3-1); the interior of the hemispherical support (3-1) is a cavity, and the diameter of the cavity is equal to the diameter of the spherical node (2-4); the diameter of the force measuring connecting rod (2-5) is equal to the diameter of the through hole (3-1A). ) are equal in diameter, the force measuring connecting rod (2-5) penetrates along the central axis of the through hole (3-1A), the diameter of the disc limiter (2-6) is equal to the inner diameter of the hollow cylindrical force measuring limiter (3-2), and the central telescopic support and the spherical node (2) are restricted from swinging. The disc limiter (2-6) can slide inside the hollow cylindrical force measuring limiter (3-2), a pressure sensor is installed on the disc limiter (2-6), and a cylindrical compression spring is arranged between the disc limiter (2-6) and the hemispherical support (3-1) along the force measuring connecting rod (2-5).

4. According to the aircraft balance parameter adjustment test bench according to claim 3, a through hole (3-1A) is provided at the axis of the hemispherical support (3-1).

5. An aircraft balance parameter adjustment test bench and its parameter adjustment method according to any one of claims 1 to 4, characterized in that: The following steps are involved: S61, adjusting the telescopic inner rod (1-2) and the telescopic outer rod (1-3) to change the position of the turbojet engine mounting ring (1-1) to adapt to aircraft of different sizes; after the adjustment is completed, locking the telescopic inner rod (1-2) and the telescopic outer rod (1-3), that is, the relative position of the telescopic inner rod (1-2) and the telescopic outer rod (1-3) is fixed; S62, a stepped turbojet engine oiling method, wherein the oiling amount changed each time is 5% of the turbojet engine's maximum oiling amount, and the hydraulic telescopic rod (2-1) is in a free state during the oiling amount change process, i.e., the relative position of the hydraulic telescopic rod (2-1) and the hydraulic telescopic rod housing (2-2) is variable, and the angle of the telescopic support rotating support (2-3) is variable. The length of the hydraulic telescopic rod (2-1) and the angle of the telescopic support rotating support (2-3) are recorded in real time. When the length of the hydraulic telescopic rod (2-1) is outside the range of 10% to 90% of the maximum length and the position of the telescopic support rotating support (2-3) is outside the range of 10% to 90% of the maximum angle, the system alarms and simultaneously outputs the total lift and thrust of each turbojet engine at that time for debugging; S63, the upper turbojet engine mounting platform (1) is stable. Due to the different thrusts of the four turbojet engines, pitch angles and roll angles appear, and the hydraulic telescopic rod (2-1) is in a locked state, that is, the relative positions of the hydraulic telescopic rod (2-1) and the hydraulic telescopic rod housing (2-2) are fixed, and the angle of the telescopic support rotating support (2-3) is fixed; S64, upper turbojet engine mounting platform (1) attitude determination, adjustment methods are divided into: 1) When the telescopic support rotating support (2-3) is located outside the range of 10% to 90% of the maximum angle, the hydraulic telescopic rod (2-1) above the center of the upper turbojet engine mounting platform (1) is reduced in length, and the hydraulic telescopic rod (2-1) below the center of the upper turbojet engine mounting platform (1) is increased in length; 2) When the length of the hydraulic telescopic rod (2-1) is outside the range of 10% to 90% of the maximum length, the telescopic support rotating support (2-3) above the center of the upper turbojet engine mounting platform (1) rotates outward, and the telescopic support rotating support (2-3) below the center of the upper turbojet engine mounting platform (1) rotates inward; 3) When the position of the telescopic support rotating support (2-3) is within the range of 10% to 90% of the maximum angle and the length of the hydraulic telescopic rod (2-1) is within the range of 10% to 90% of the maximum length, the hydraulic telescopic rod (2-1) above the center of the upper turbojet engine mounting platform (1) is reduced in length, and the telescopic support rotating support (2-3) is rotated outwardly, while the hydraulic telescopic rod (2-1) below the center of the upper turbojet engine mounting platform (1) is increased in length, and the telescopic support rotating support (2-3) is rotated inwardly; 4) When the position of the telescopic support rotating support (2-3) is outside the range of 10% to 90% of the maximum angle, and the length of the hydraulic telescopic rod (2-1) is outside the range of 10% to 90% of the maximum length, the system alarms and simultaneously outputs the total lift and thrust of each turbojet engine at this time for debugging; S65. Using a BP neural network to adjust in real time the proportional adjustment coefficient, differential adjustment coefficient, and integral adjustment coefficient of the PID controller for controlling the length of the hydraulic telescopic rod (2-1) and the PID controller for controlling the angle of the telescopic support and rotating support (2-3), so that they can adapt to the control requirements of the aircraft under different circumstances. During the adjustment process, a balance strategy of exploration and exploitation can be adopted. By trying and evaluating different parameter combinations, the performance of the length control PID controller and the angle control PID controller can be gradually optimized. S66, after the attitude adjustment is completed, the hydraulic telescopic rod (2-1) is released to be in a free state, the fuel supply to the turbojet engine is increased, and S62 to S65 are repeated until the maximum fuel supply is achieved; S67. After the maximum fuel injection attitude adjustment is completed, the test is completed, and the relationship between the fuel injection and the total lift, the fuel injection and the thrust of each turbojet engine, as well as the proportional adjustment coefficient, differential adjustment coefficient and integral adjustment coefficient of the angle control and length control PID controllers are obtained. The relationship between the fuel injection and the total lift, and the fuel injection and the thrust of each turbojet engine is used to judge whether the parameters of the angle control and length control PID controllers are optimal. The proportional adjustment coefficient, differential adjustment coefficient and integral adjustment coefficient of the angle control and length control PID controllers can be calculated to obtain the proportional adjustment coefficient, differential adjustment coefficient and integral adjustment coefficient of the turbojet engine control PID controller.

6. The aircraft balance parameter adjustment test bench and the parameter adjustment method thereof according to claim 5, characterized in that: The calculation method of total lift and thrust of each turbojet engine is: The position motion equation of the UAV is: Among them, m represents the mass of the drone, and [xyz] T They represent the net external force acting on the UAV and the center of mass position of the quadrotor UAV respectively; During the test of the upper turbojet engine mounting platform (1), it can be seen from the force analysis that the external force mainly includes the lift generated by the turbojet and its own gravity, so the total external force F on the upper turbojet engine mounting platform (1) is p for: in, represents the lift generated by the turbojet engine in the coordinate system of the upper turbojet engine mounting platform (1), represents the weight of the upper turbojet engine mounting platform (1) itself in the inertial coordinate system, Indicates the pulling force exerted by the middle telescopic support and spherical node (2) on the upper turbojet engine mounting platform (1) through the hydraulic telescopic rod (2-1) in the inertial coordinate system. represents the pulling force exerted by the connecting spring (2-7) on the upper turbojet engine mounting platform (1) in the inertial coordinate system; It can be described as the superposition of the lift generated by four turbojet engines, then: The weight of the upper turbojet engine mounting platform (1) itself It can be described as: where m p represents the mass of the upper turbojet engine mounting platform (1), g represents the gravity coefficient of the earth's gravity; The tension of the connecting spring (2-7) on the upper turbojet engine mounting platform (1) It can be described as: Among them F t Indicates the elastic force of the connecting spring (2-7); After adjustment, the upper turbojet engine mounting platform (1) is in a force-balanced state, at which point: F p ＝0 Based on the above analysis, it can be seen that the pulling force exerted by the middle telescopic support and the spherical node (2) on the upper turbojet engine mounting platform (1) is for: Wherein, θ, φ and ψ represent the pitch angle, roll angle and yaw angle of the upper turbojet engine mounting platform (1), respectively; represents the resultant force produced by four turbojet engines; The vertical total external force on the spherical node (2-4) for: in, represents the gravity of the middle telescopic support and the spherical node (2) in the inertial coordinate system, Indicates the reaction force on the disk limiter (2-6) in the inertial coordinate system, the gravity of the central telescopic support and the spherical node (2) itself It can be expressed as: Reaction force on the disc limiter (2-6) is the value of the pressure sensor; Based on the above analysis, we can know that: Among them, α i is the angle between the telescopic outer rod (1-3) and the horizontal plane, is the pulling force exerted by a single telescopic inner rod (1-2) on the upper turbojet engine mounting platform (1), then the lift generated by the four turbojet engines can be described as: The force analysis of the single upper turbojet engine mounting platform (1) shows: Among them, M p is the bending moment in the middle of the single upper turbojet engine mounting platform (1), D i is the distance from the center of the upper turbojet engine mounting platform (1) to the center of the turbojet engine mounting ring (1-1), β i is the angle between the telescopic inner rod (1-2) and the plane of the upper turbojet engine mounting platform (1), and β i =f(θ,φ,α i ), The distance from the center of the upper turbojet engine mounting platform (1) to the action point of the hydraulic telescopic rod (2-1); Based on the above theoretical analysis, the thrust of each turbojet engine can be described as:

7. The aircraft balance parameter adjustment test bench parameter adjustment method according to claim 5, characterized in that: PID parameters include angle control PID parameters, length control PID parameters and turbojet engine control PID parameters. Angle control output: in, is the angle proportional adjustment coefficient, is the angle integral adjustment coefficient, is the angle differential adjustment coefficient; u α (k) is the kth angle control output, e α (k) is the angle error value calculated for the kth time, e α (j) is the angle error value calculated for the jth time, e α (k-1) is the angle error value calculated for the k-1th time; Length control output: in, is the length ratio adjustment coefficient, is the length integral adjustment coefficient, is the length differential adjustment coefficient; u l (k) is the k-th length control output, e l (k) is the length error value calculated for the kth time, e l (j) is the length error value calculated for the jth time, e l (k-1) is the length error value calculated for the k-1th time; Turbojet engine control output: in, is the turbojet engine proportional adjustment coefficient, is the integral adjustment coefficient of the turbojet engine, is the differential adjustment coefficient of the turbojet engine; u b (k) is the kth turbojet engine control output, e b (k) is the error value of the turbojet engine calculated for the kth time, e b (j) is the length error value calculated for the jth time, e b (k-1) is the error value of the turbojet engine calculated for the k-1th time; When the angle error value e α When it is relatively small, the error value e of the turbojet engine is b It can be expressed as: to b =R·(the α +e l ) Wherein, R is a coefficient determined by the average distance from the center of the upper turbojet engine mounting platform (1) to the center of the turbojet engine mounting ring (1-1), and the average distance from the center of the upper turbojet engine mounting platform (1) to the action point of the hydraulic telescopic rod (2-1), and l is the length of the connecting spring (2-7); Similarly, the turbojet engine control output u b (k) can be expressed as: in b (k)=Au α (k)+Bu l (k) Among them, A and B are coefficients; Based on the above theoretical analysis, it can be seen that the turbojet engine proportional adjustment coefficient Turbojet engine integral adjustment coefficient Turbojet engine differential adjustment coefficient It can be described as:

8. The aircraft balance parameter adjustment test bench and the parameter adjustment method thereof according to claim 5, characterized in that: Adjusting PID parameters using BP neural network includes the following steps: S91, Data acquisition and preprocessing: Collect input and output data of the aircraft balance parameter adjustment test bench and preprocess the data; S92. BP neural network model design and training: Establish a BP neural network model and use the collected pre-processed data to train the BP neural network using the back propagation algorithm; S93, PID controller design: Based on BP neural network, design angle control and length control PID controllers; S94, real-time control and feedback adjustment: Combine the trained BP neural network with the angle control and length control PID controllers and apply them to the test bench system. By collecting sensor data in real time, calculating control signals and controlling actuators, the real-time control of the test bench system and the optimization of the angle control and length control PID controller parameters are achieved.

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