A balance compensation control method for the transition process of a tilt-rotor aircraft

Abstract

The present invention discloses a balance compensation control method for a transition process of a tilt-rotor aircraft, comprising: signal processing, balance coefficient identification and compensation output: the signal processing is to obtain various flight parameters of the tilt-rotor aircraft based on a displacement sensor and a phase sensor, and calculate the longitudinal aerodynamic resultant force and resultant torque of the tilt-rotor aircraft; the balance coefficient identification is based on the transition flight altitude and pitch angle of the tilt-rotor aircraft as a control basis, and the tilt-wing angle of attack is used as a judgment basis, and the balance coefficient is obtained by identification through a hybrid particle swarm iterative search algorithm; the compensation output is to generate a compensation signal through a balance compensation controller, and the control signal after superposition with the original signal is input into the rotor and the elevator, so as to suppress the unbalanced vibration generated during the transition switching process of the tilt-rotor aircraft. The present invention can realize active compensation for the unbalanced vibration generated by the control signal when the transition controller is switched, thereby improving the flight stability of the tilt-rotor aircraft during the entire transition process.

Description

Technical Field

[0001] The present invention relates to the technical field of variable structure aircraft control, and in particular to a balance compensation control method for a tilt-rotor aircraft during a transition process. Background Art

[0002] Flexible, lightweight small drones offer significant advantages in civilian operations and military reconnaissance. Tilt-rotor aircraft, a new type of unmanned aerial vehicle (UAV) with a variable-structure design, utilize a portion of the wings that tilt in conjunction with the rotors. Tilt-rotor aircraft operate in three modes: takeoff and landing, transition mode, and cruise mode. Unlike tilt-rotor aircraft, their unique tilting structure effectively minimizes lift loss caused by rotor downwash being blocked by the wings during takeoff and landing, thereby reducing energy consumption and increasing range.

[0003] In transition mode, various aerodynamic interferences exist between the various components of the aircraft, and multiple flight parameters are coupled, forming a time-varying, strongly coupled, nonlinear, and complex system. To ensure effective control, transition mode employs a switching control strategy in which control parameters dynamically change with flight conditions. The operating point of a tilt-rotor aircraft is switched by controlling rotor speed and elevator deflection. During switching, the tilt-rotor angle of attack is adjusted to the target value, and the rotor speed and elevator lift are rapidly adjusted to maintain a stable altitude. Because the aircraft is a strongly coupled, nonlinear, and time-varying system, switching operating points often results in jitter in the control signals, necessitating the development of an appropriate switching control strategy.

[0004] Effectively suppressing jitter in switching control signals and ensuring stable altitude during transitional flight for tilt-rotor aircraft remain key technologies and challenges. Current approaches can be categorized into two main types: one employs nonlinear processing between the actual system input and the desired controller output to suppress jitter, while the other relies on quadratic anti-shake control, which requires the input and output of the online and offline controllers to be as close as possible. These methods require the compensator to remain online, and some compensation methods are ineffective in suppressing switching jitter.

[0005] Therefore, the existing technology lacks a method that can ensure that the flight altitude remains stable, the algorithm is simple and easy to implement, and the real-time performance meets the requirements, and can suppress the switching signal jitter during the transition process of the tilt-rotor aircraft while reducing the system cost. Summary of the Invention

[0006] The purpose of the present invention is to solve the technical problems existing in the prior art and to provide a balance compensation control method for a tiltrotor aircraft during a transition process.

[0007] To achieve the above-mentioned object, the present invention provides a technical solution: a balance compensation control method for a tiltrotor aircraft during a transition process, the method comprising the following steps:

[0008] a. Real-time and sequential signal processing: The displacement sensor obtains the tilt-wing aircraft's forward flight velocity u, vertical velocity w, flight altitude h, and flight distance x during the transition process. The phase sensor obtains the tilt-wing aircraft's pitch angular velocity q and pitch angle θ, and calculates the components F of the resultant force on the tilt-wing aircraft in addition to gravity on the x-axis and z-axis. x 、F z The pitching moment M is generated by the sum of the rotor pull and the aerodynamic force of the tilt-rotor aircraft except for gravity;

[0009] b. Balance coefficient identification: Taking the flight altitude deviation E(k) and pitch angle θ of the tilt-wing aircraft during the transition process as the control basis, and the tilt-wing angle of attack Ah as the judgment basis, the hybrid particle swarm iterative search method is used to identify and calculate the balance coefficient and output the coefficient matrix T of the transition balance controller. i ;

[0010] c. Compensation Output: The transition balance controller generates a compensation signal, which is superimposed on the original signal to generate the control signal for the rotor thrust F and the elevator additional lift δ. This signal is then input into the rotor and elevator to suppress the unbalanced vibration generated during the transition switching process of the tilt-rotor aircraft.

[0011] Preferably, the signal processing is to calculate the aerodynamic force of the tilt-rotor aircraft according to the split method, and perform superposition operation on the forces and moments of each part to obtain the longitudinal aerodynamic resultant force and resultant moment of the tilt-rotor aircraft.

[0012] Preferably, the signal processing is for longitudinal aerodynamic analysis of the transition process of the tilt-wing aircraft, and the establishment of the body coordinate system and the ground coordinate system is specifically:

[0013] Aircraft coordinate system Oxyz: The origin O is located at the center of mass of the aircraft, the x-axis points forward along the aircraft axis, the y-axis points to the right and is perpendicular to the aircraft's symmetry plane, and the z-axis is perpendicular to the aircraft's horizontal plane and points downward;

[0014] Ground coordinate system OgXgYgZg: The origin Og is fixed to any point on the ground, the Xg and Yg axes are parallel to the ground and perpendicular to each other, and the Zg axis is perpendicular to the ground and points to the center of the earth.

[0015] Preferably, the flight parameters of the tilt-rotor aircraft during the transition process are calculated using the following formula based on the longitudinal aerodynamic resultant force and the resultant moment:

[0016]

[0017] Iy is the moment of inertia about the y-axis.

[0018] Preferably, the tilt-rotor aircraft transition balance controller in step b includes: a forward flight speed controller and a pitch attitude controller

[0019] Preferably, the hybrid particle swarm iterative search method in step b includes: first setting the initial value X0 of the identification value and the identification boundary, starting from the initial value of the identification value, using the hybrid particle swarm iterative search method while changing the search step size, so that the identification value is infinitely close to the target value, and the final output identification value X F As the target value X T , as the final tilt-rotor aircraft transition process control balance coefficient.

[0020] Preferably, the hybrid particle swarm iterative search specifically adopts a combined particle swarm algorithm of simulated annealing and taboo discrimination, and its combination logic is:

[0021] When a differential solution is found in the iterative search, the annealing idea is introduced to calculate the state transition probability of the differential solution. If the probability is passed, the differential solution is accepted; otherwise, the differential solution is not accepted.

[0022] When an optimal solution appears during iterative search, the taboo concept is introduced. A taboo table is established and the optimal solution is written into the taboo table. The taboo table is then queried the next time an optimal solution appears. If the taboo query passes, the optimal solution is accepted; if the taboo query fails, the optimal solution is not accepted.

[0023] Preferably, the transition balance controller in step c adopts a fuzzy switching PID controller to perform real-time compensation for control signal vibration caused by transition switching of the tilt-rotor aircraft.

[0024] Beneficial effects of the present invention:

[0025] (1) The present invention adopts an iterative search algorithm to identify the balance controller and optimizes the stability problem of the transition flight control system.

[0026] (2) The variable step size algorithm in the present invention not only ensures the algorithm identification accuracy, but also improves the algorithm convergence speed.

[0027] (3) The hybrid particle swarm iterative search algorithm adopted in the present invention combines the advantages of simulated annealing and taboo discrimination. The algorithm is simple and easy to implement and can run in existing conventional digital controllers, effectively reducing system costs.

[0028] (4) The fuzzy switching controller designed in the present invention can not only effectively reduce the altitude fluctuation of the tilt-rotor aircraft during the transition process, but also reduce the control signal vibration caused by switching.

[0029] (5) The present invention combines the hybrid particle swarm algorithm with the switching fuzzy controller, so that the compensation controller does not need to operate all the time, but only needs to actively compensate at the switching time, which takes up little control system resources.

[0030] (6) The present invention is not only applicable to the transition conditions of tiltrotor aircraft, but also to the smooth switching control in similar mechanical and electronic systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings described herein are used to provide further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0032] Figure 1 It is a principle block diagram of the present invention;

[0033] Figure 2 It is a tilt-rotor aircraft structure;

[0034] Figure 3 The coordinate system for the tilt-rotor aircraft is defined;

[0035] Figure 4 A transition control system structure for a tiltrotor aircraft;

[0036] Figure 5 It is the flow chart of hybrid particle swarm;

[0037] Figure 6 Identify fuzzy PID controller parameters for hybrid particle swarm optimization;

[0038] Figure 7 is a curve showing the change of flight altitude over time during the transition process of the tiltrotor aircraft;

[0039] Figure 8 Curves showing rotor thrust (a) and elevator additional lift (b) changing with time under different control strategies. DETAILED DESCRIPTION

[0040] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it should not be understood as a limitation on the scope of protection of the present invention.

[0041] Reference Figures 1-8 A preferred embodiment of the present invention provides a balance compensation control method for a tilt-rotor aircraft during a transition process, the method comprising the following steps:

[0042] a. Real-time and sequential signal processing: The displacement sensor obtains the tilt-wing aircraft's forward flight velocity u, vertical velocity w, flight altitude h, and flight distance x during the transition process. The phase sensor obtains the tilt-wing aircraft's pitch angular velocity q and pitch angle θ, and calculates the components F of the resultant force on the tilt-wing aircraft in addition to gravity on the x-axis and z-axis. x 、F z The pitching moment M generated by the sum of the rotor pull and the aerodynamic force of the tilt-rotor aircraft except gravity; the displacement sensor and the phase sensor are both non-contact sensors;

[0043] b. Balance coefficient identification: Taking the flight altitude deviation E(k) and pitch angle θ of the tilt-wing aircraft during the transition process as the control basis, and the tilt-wing angle of attack Ah as the judgment basis, the hybrid particle swarm iterative search method is used to identify and calculate the balance coefficient and output the coefficient matrix T of the transition balance controller. i ;

[0044] c. Compensation Output: The transition balance controller generates a compensation signal, which is superimposed on the original signal to generate the control signal for the rotor thrust F and the elevator additional lift δ. This signal is then input into the rotor and elevator to suppress the unbalanced vibration generated during the transition switching process of the tilt-rotor aircraft.

[0045] The tilt-rotor aircraft has three controlled components in the transition mode: a rotor motor, a pitch servo, and a tilt servo.

[0046] As a preferred embodiment of the present invention, it may also have the following additional technical features:

[0047] In this embodiment, the signal processing is to calculate the aerodynamic force of the tilt-rotor aircraft according to the split method, and perform superposition operation on the forces and moments of each part to obtain the longitudinal aerodynamic resultant force and moment of the tilt-rotor aircraft.

[0048] In this embodiment, the signal processing is aimed at analyzing the longitudinal aerodynamic force during the transition process of the tilt-wing aircraft. The establishment of the body coordinate system and the ground coordinate system is specifically as follows:

[0049] Aircraft coordinate system Oxyz: The origin O is located at the center of mass of the aircraft, the x-axis points forward along the aircraft axis, the y-axis points to the right and is perpendicular to the aircraft's symmetry plane, and the z-axis is perpendicular to the aircraft's horizontal plane and points downward;

[0050] Ground coordinate system OgXgYgZg: The origin Og is fixed to any point on the ground, the Xg and Yg axes are parallel to the ground and perpendicular to each other, and the Zg axis is perpendicular to the ground and points to the center of the earth.

[0051] In this embodiment, the flight parameters of the tilt-rotor aircraft during the transition process are calculated using the following formula based on the longitudinal aerodynamic resultant force and the resultant moment:

[0052]

[0053] I y is the moment of inertia about the y-axis.

[0054] In this embodiment, the transition balance controller of the tiltrotor aircraft in step b includes a forward flight speed controller and a pitch attitude controller.

[0055] In this embodiment, the hybrid particle swarm iterative search method in step b includes: first setting the initial value X0 of the identification value and the identification boundary, starting from the initial value of the identification value, using the hybrid particle swarm iterative search method while changing the search step size, so that the identification value is infinitely close to the target value, and the final output identification value X F As the target value X T , as the final tilt-rotor aircraft transition process control balance coefficient.

[0056] In this embodiment, the hybrid particle swarm iterative search specifically adopts a combined particle swarm algorithm of simulated annealing and taboo discrimination, and its combination logic is:

[0057] When a differential solution is found in the iterative search, the annealing idea is introduced to calculate the state transition probability of the differential solution. If the probability is passed, the differential solution is accepted; otherwise, the differential solution is not accepted.

[0058] When an optimal solution appears during iterative search, the taboo concept is introduced. A taboo table is established and the optimal solution is written into the taboo table. The taboo table is then queried the next time an optimal solution appears. If the taboo query passes, the optimal solution is accepted; if the taboo query fails, the optimal solution is not accepted.

[0059] In this embodiment, the transition balance controller in step c is a fuzzy switching PID controller, wherein both the rotor motor and the elevator are controlled using a fuzzy PID strategy. This method provides real-time compensation for control signal vibration caused by transition switching in a tilt-rotor aircraft, suppressing signal jitter caused by switching.

[0060] For the transition process of the tilt-rotor aircraft, the rotor motor is controlled by adjusting the speed to target the forward flight speed of the aircraft, the elevator is controlled by deflecting to target the pitch attitude of the aircraft, and the tilt-rotor servo is controlled to target the tilt-wing angle of attack.

[0061] The entire system consists of three control loops: the rotor thrust F control loop, the elevator additional lift δ control loop, and the tilt rotor angle of attack Ah control loop. The elevator control loop adopts a dual closed-loop control structure, with the outer control loop being the pitch angle thd feedback loop and the inner control loop being the pitch angle velocity q feedback loop.

[0062] Specifically, through the analysis of the aerodynamic force of the aircraft during the tilting period, the aerodynamic center of the aircraft basically does not change during the tilting process, so the aerodynamic center of each part of the tilt-rotating wing aircraft is uniformly represented by Ob1.

[0063] The split method is used to calculate the aerodynamic force on any side of each part of the tiltrotor aircraft:

[0064] For the fixed wing part of the tilt-rotor aircraft, the area of ​​the fixed wing part is greatly shortened compared with the traditional tilt-rotor aircraft. The fixed wing aerodynamic force is converted to the body coordinate system as follows:

[0065]

[0066] Where, L W is the fixed-wing lift, D W is the fixed wing resistance, d w is the projection distance from the aerodynamic center of the wing to the center of gravity of the aircraft in the longitudinal plane, α w Indicates the actual airspeed of a fixed wing relative to the angle of attack of the fixed wing surface.

[0067] For the tilt-rotor aircraft rotor model, the rotors on both sides of the aircraft operate at the same speed and in opposite directions. The present invention uses the rotor thrust as a control quantity, that is, the upward lift generated by the rotor rotation is the positive direction. The rotor aerodynamic force is converted to the body coordinate system as:

[0068]

[0069] Where, α f is the rotor thrust axis angle of attack, and η is the installation angle between the rotor and the tilt rotor.

[0070] During flight, the pitch attitude of a tiltrotor aircraft is controlled primarily by adjusting the additional lift of the horizontal tail and elevator. Therefore, for the horizontal tail model, the additional lift of the elevator needs to be used as a control variable. That is, when the elevator rotates upward along the axis, the additional lift generated is in the downward direction. The aerodynamic force converted to the aircraft coordinate system is:

[0071]

[0072] Where, δ e Add lift to the elevator, q p is the horizontal tail pitch angular velocity, S p is the reference mask of the horizontal tail, Cl is the lift coefficient, Lp is the horizontal tail lift, D p is the horizontal tail drag, d p is the projection distance from the aerodynamic center of the horizontal tail to the center of gravity of the aircraft in the longitudinal plane, α p is the angle between the horizontal tail airspeed and the body coordinate system.

[0073] Specifically, in transition mode, the tilt-wing's angle of attack changes from 88° to 2°. This change in lift and drag coefficients is a key factor contributing to the nonlinear characteristics of tilt-wing aircraft. Therefore, for the tilt-wing model, the tilt angle of attack needs to be used as the control variable, meaning that the tilt-wing's downward rotation along the axis is considered the positive direction. The aerodynamic force converted to the aircraft coordinate system is:

[0074]

[0075] Where, L q is the tilt-rotor lift, D q is the tilt wing resistance, d q is the projection distance from the aerodynamic center of the tiltrotor to the center of gravity of the aircraft in the longitudinal plane, α q is the tiltrotor angle of attack.

[0076] Superimpose the aerodynamic forces and pitching moments on the left and right sides of each part of the tilt-rotor aircraft to calculate the longitudinal aerodynamic resultant force and pitching resultant moment of the tilt-rotor aircraft:

[0077]

[0078] Where, F x 、F z are the components of the resultant force on the tilt-rotor aircraft in addition to gravity on the x-axis and z-axis, respectively, and M is the pitch moment generated by the sum of the rotor pull and the aerodynamic forces of various parts of the aircraft in addition to gravity.

[0079] Since the aerodynamic coefficients of the tilt-rotor aircraft are constantly changing during the transition process, it is difficult for the traditional single control method to cover the entire operation process. According to the change law of the lift and drag coefficients of the tilt-rotor aircraft, the transition process can be divided into several working sections. The differences between the working sections are mainly the tilt-wing angle of attack, forward flight speed, and pitch attitude. The structure of the tilt-rotor aircraft transition control system is as follows: Figure 4 As shown,

[0080] The hybrid particle swarm iterative search specifically adopts a combined particle swarm algorithm of simulated annealing and taboo discrimination, such as Figure 5 As shown, its combination logic is:

[0081] When a differential solution exists in the iterative search, the annealing idea is introduced to calculate the state transition probability of the differential solution. If the probability passes, the differential solution is accepted; otherwise, the differential solution is not accepted.

[0082] When an optimal solution appears during iterative search, the taboo concept is introduced. A taboo table is established and the optimal solution is written into the taboo table. The taboo table is then queried the next time an optimal solution appears. If the taboo query passes, the optimal solution is accepted; if the taboo query fails, the optimal solution is not accepted.

[0083] The fuzzy PID strategy adopted in this invention uses a hybrid particle swarm algorithm to identify the optimal PID parameters at each stage, such as Figure 6 As shown. A fuzzy compensator is introduced at the switching moment to compensate the controller online in the form of PID parameter increments. Taking the rotor thrust controller as an example, its incremental fuzzy PID expression is:

[0084]

[0085] Where k p0 、k i0 、k d0 is the initial value of the controller, Δk pF , Δk iF , Δk dF Fuzzy increment. For fuzzy discrimination, the Mamdani method is used for fuzzy reasoning, and the Centroid method is used for defuzzification. The fuzzy control rules are formulated according to the following principles: first, to ensure the stability of the tilt-rotor aircraft during the transition phase, reduce flight altitude overshoot, and reduce control signal jitter. On this premise, the transition process time is shortened and the system operation efficiency is improved.

[0086] In order to verify the effectiveness of the proposed balance compensation control method for the transition process of the tilt-rotor aircraft, a system was built in MATLAB / SIMULINK as follows: Figure 4 The simulation model shown.

[0087] Analysis of the aerodynamic characteristics of a tilt-wing aircraft during transition mode reveals that the transition mode can be divided into three phases: early, mid, and late phases. The dynamic parameters of the tilt-wing aircraft system vary significantly during these phases, making it difficult to achieve the desired control effect using a single set of control parameters. Different fuzzy-PID controllers are used for different control phases of the tilt-wing aircraft, and a hybrid particle swarm algorithm is employed to perform online identification of the controller coefficients.

[0088] The control process simulated by the present invention starts from the hovering mode of the tilt-wing aircraft. The tilt-wing angle of attack is tilted from 88° to 2° at a transition rate given by the controller. According to the changes in the dynamic characteristics of the tilt-wing aircraft in the transition section, a switching control method is adopted to match different controllers in different control processes to achieve the optimal control effect.

[0089] The curve of the tilt-rotor aircraft's transition mode flight altitude changing with time is as follows: Figure 7 As shown in the figure, the simulation results show that the control strategy of fuzzy PID optimized by hybrid particle swarm algorithm can effectively suppress the altitude fluctuation of tilt-rotor aircraft during the transition process, and the flight altitude is well controlled. The curves of rotor thrust and elevator additional lift changing with time under different control strategies are shown in the figure. Figure 8As the tilting progresses, the aircraft's rotor thrust and elevator lift under the traditional PID control strategy experience severe fluctuations, resulting in significant overshoot in the control response and a mismatch between the control parameters and the time-varying system. However, using a hybrid particle swarm algorithm to identify and optimize the fuzzy PID strategy alleviates the control signal jitter problem, effectively compensating for signal vibrations that occur during the switching moment, and significantly improving the robustness of the control system.

[0090] Under the premise that no conflict occurs, those skilled in the art may freely combine and superimpose the above-mentioned additional technical features.

[0091] The above descriptions are only preferred embodiments of the present invention. Any technical solution that achieves the purpose of the present invention by substantially the same means shall fall within the scope of protection of the present invention.

Claims

1. A balance compensation control method for a tiltrotor aircraft during a transient process, characterized by: The method comprises the following steps: a. Real-time and sequential signal processing: The displacement sensor obtains the forward flight velocity u, vertical velocity w, flight altitude h, and flight distance x of the tilt-wing aircraft during the transition process. The phase sensor obtains flight parameters including the pitch angular velocity q and pitch angle θ of the tilt-wing aircraft. The components F of the resultant force on the tilt-wing aircraft in addition to gravity on the x-axis and z-axis are calculated. x 、F z The pitching moment M is generated by the sum of the rotor pull and the aerodynamic force of the tilt-rotor aircraft except for gravity; b. Balance coefficient identification: Taking the flight altitude deviation E(k) and pitch angle θ of the tilt-wing aircraft during the transition process as the control basis, and the tilt-wing angle of attack Ah as the judgment basis, the hybrid particle swarm iterative search method is used to identify and calculate the balance coefficient and output the coefficient matrix T of the transition balance controller. i ; c. Compensation output: The transition balance controller generates a compensation signal, which is superimposed on the original signal to generate control signals for the rotor thrust F and the elevator additional lift δ. These signals are then input into the rotor and elevator to suppress the unbalanced vibrations generated during the transition switching process of the tilt-rotor aircraft. The hybrid particle swarm iterative search method in step b includes: first setting the initial value X0 of the identification value and the identification boundary, starting from the initial value of the identification value, using the hybrid particle swarm iterative search method while changing the search step size to make the identification value infinitely close to the target value, and finally outputting the identification value X F As the target value X T , as the final tilt-rotor aircraft transition process control balance coefficient; The hybrid particle swarm iterative search specifically adopts a combined particle swarm algorithm of simulated annealing and taboo discrimination at the same time, and its combination logic is: When a differential solution is found in the iterative search, the annealing idea is introduced to calculate the state transition probability of the differential solution. If the probability is passed, the differential solution is accepted; otherwise, the differential solution is not accepted. When an optimal solution is found in the iterative search, a taboo concept is introduced. A taboo table is established and the optimal solution is written into the taboo table. The taboo table is then queried the next time an optimal solution is found. If the taboo query passes, the optimal solution is accepted; if the taboo query fails, the optimal solution is rejected. The transition balance controller in step c adopts a fuzzy switching PID controller, and the rotor motor and elevator are controlled by a fuzzy PID strategy to perform real-time compensation for the control signal vibration caused by the transition switching of the tilt-rotor aircraft.

2. The balance compensation control method for a tiltrotor aircraft during a transition process according to claim 1, characterized in that: The signal processing is to calculate the aerodynamic force of the tilt-rotor aircraft based on the split method, and perform superposition operation on the forces and moments of each part to obtain the longitudinal aerodynamic resultant force and moment of the tilt-rotor aircraft.

3. The balance compensation control method for a tilt-rotor aircraft during a transition process according to claim 2, characterized in that: The signal processing is aimed at analyzing the longitudinal aerodynamic force of the tilt-rotor aircraft during the transition process. The establishment of the body coordinate system and the ground coordinate system is specifically as follows: Aircraft coordinate system Oxyz: The origin O is located at the center of mass of the aircraft, the x-axis points forward along the aircraft axis, the y-axis points to the right and is perpendicular to the aircraft's symmetry plane, and the z-axis is perpendicular to the aircraft's horizontal plane and points downward; Ground coordinate system OgXgYgZg: The origin Og is fixed to any point on the ground, the Xg and Yg axes are parallel to the ground and perpendicular to each other, and the Zg axis is perpendicular to the ground and points to the center of the earth.

4. The balance compensation control method for a tilt-rotor aircraft during a transition process according to claim 3, characterized in that: According to the longitudinal aerodynamic resultant force and the resultant moment, the following formula is used to calculate the flight parameters of the tilt-rotor aircraft during the transition process: I y is the moment of inertia about the y-axis.

5. The balance compensation control method for a tiltrotor aircraft during a transition process according to claim 1, characterized in that: The tiltrotor aircraft transition balance controller in step b includes: a forward flight speed controller and a pitch attitude controller.

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