A flight attitude adjusting method of a sightseeing flight motorcycle

Abstract

The present application relates to the technical field of aircraft control, and discloses a flight attitude adjusting method for a sightseeing flight motorcycle, which comprises the following steps: constructing a nonlinear dynamic model of the flight motorcycle; monitoring the body tilting angle and its change rate; entering a feedforward compensation mode when the tilting angle enters a critical range or the change rate exceeds a threshold; calculating a pitch channel compensation moment and a lift channel compensation force based on model predictive control, with attitude deviation and residual tilting stroke as constraints; further mapping the tilting angle adjusting amount and the rotating speed adjusting amount through a force and moment distribution matrix, and synchronously executing the tilting mechanism and the rotor motor. Through the design of phased priority constraints, static-dynamic dual-mode decoupling, health degree redundant distribution and self-adaptive time domain adjustment mechanism, the present application effectively solves the problems of attitude divergence and height drop in the mode conversion process of the flight motorcycle, enhances the robustness of the flight motorcycle under different working conditions, and improves the driving safety and the riding comfort.

Description

Technical Field

[0001] This invention relates to the field of aircraft control technology, and in particular to a method for adjusting the flight attitude of a sightseeing flying motorcycle. Background Technology

[0002] As a new type of low-altitude manned aircraft, sightseeing flying motorcycles face one of the core technological challenges in controlling the transition from hovering mode to level flight mode. During the mode transition, the tilt mechanism drives the rotor to gradually tilt from a vertical position to a horizontal position. The fuselage attitude, aerodynamic force and rotor thrust exhibit strong nonlinear coupling characteristics, which can easily lead to problems such as fuselage altitude loss, pitch oscillation and even attitude divergence, seriously affecting passenger comfort and flight safety.

[0003] Currently, attitude control for multirotor aircraft mainly employs PID control or linear model predictive control. These methods typically assume that the aircraft's center of gravity is fixed and aerodynamic parameters are constant, making it difficult to adapt to drastic changes in aerodynamic characteristics during mode transitions. They are prone to failure when the load or ambient wind speed changes. In addition, in existing technologies, the tilting mechanism and rotor motor are often controlled independently without fully considering the dynamic coupling between the two, leading to mutual interference of control commands and a decline in control quality.

[0004] At the control distribution level, existing aircraft typically use a fixed force and torque distribution matrix, ignoring the drift in distribution characteristics caused by changes in load distribution, aging of actuators, or changes in environmental conditions. After long-term use, the control accuracy decreases. At the same time, traditional distribution methods lack redundancy and fault tolerance, and are prone to loss of control risks due to single-point failure of actuators.

[0005] In summary, there is an urgent need for a flight attitude adjustment method that can adapt to the strong nonlinearity and strong coupling characteristics during mode transitions. This method should be able to adaptively adjust control parameters under different load and environmental conditions, achieve coordinated control of the tilting mechanism and rotor motor, and have fault-tolerant allocation capability when the actuator margin is insufficient, thus ensuring the attitude stability and flight safety of the flying motorcycle during mode transitions. Summary of the Invention

[0006] The purpose of this invention is to provide a method for adjusting the flight attitude of a sightseeing flying motorcycle in order to solve the problems in the prior art.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a method for adjusting the flight attitude of a sightseeing flying motorcycle, comprising the following steps: S1. Before the flying motorcycle transitions from hovering mode to level flight mode, a nonlinear dynamic model is constructed based on the actual tilt angle of its tilt mechanism, airspeed, and the current attitude angle of the aircraft measured by the inertial measurement unit. S2, during the transition of the flying motorcycle from hovering mode to level flight mode, the actual tilt angle and its rate of change are monitored. When the actual tilt angle enters the preset critical tilt angle range, or the rate of change is greater than the preset tilt angle change rate threshold, the feedforward compensation control mode is entered. S3, under the feedforward compensation control mode, based on the nonlinear dynamic model, with the deviation between the current attitude angle and the target attitude angle and the remaining tilt stroke from the actual tilt angle to the target tilt angle during the mode conversion process as constraints, the control sequence in the time domain of the mode conversion process is solved by rolling optimization, and the pitch channel compensation torque and lift channel compensation force used for mode conversion are calculated. S4, the pitch channel compensation torque and lift channel compensation force are mapped to the tilt angle adjustment amount of the tilt mechanism and the speed adjustment amount of the independent rotor motor respectively through the force and torque distribution matrix, and the tilt mechanism and rotor motor respond simultaneously and execute the corresponding adjustment actions.

[0008] The beneficial effects of the technical solution provided by this invention include at least the following: This invention constructs a nonlinear dynamic model and uses a feedforward compensation control mode triggered by two conditions: tilt angle and its rate of change. This allows for timely intervention when the mode transition enters the unsteady aerodynamic range, effectively suppressing issues such as fuselage altitude loss and attitude divergence. Furthermore, by dividing the mode transition process into three stages—initial, transition, and approach—and setting differentiated constraint priorities for each stage, this invention achieves a progressive control strategy that prioritizes altitude maintenance before attitude adjustment, significantly improving the stability and safety of the mode transition process.

[0009] This invention adaptively adjusts the tilt angle change rate threshold by acquiring real-time load mass and ambient wind speed, enabling the triggering conditions of feedforward compensation control to dynamically change with flight conditions. This improves upon the problem that traditional fixed thresholds are too aggressive under heavy loads and too conservative under light loads. At the same time, this invention updates the force and torque distribution matrix online using a recursive least squares algorithm to compensate for the mismatch in distribution characteristics caused by changes in load distribution, aerodynamic parameter drift, or actuator aging. The system can maintain high control accuracy even after long-term operation.

[0010] This invention introduces an actuator health index to evaluate the control margin of each actuator in real time. When the pitch compensation torque is large, the command is preferentially allocated to the actuator with high health. When the lift compensation force is large, only the rotor motor undertakes the control task, thus avoiding the introduction of additional pitch interference. This redundancy allocation mechanism can effectively prevent control failure caused by single point of failure or overload, thereby extending the service life of the actuator.

[0011] This invention designs a timing synchronization control mechanism to address the difference in response speed between the tilt mechanism and the rotor motor. By comparing the estimated action time with the estimated response time, the starting sequence of the tilt mechanism and the rotor motor is intelligently determined. When necessary, the speed adjustment is decomposed into a pre-adjustment component and a main adjustment component, and executed in stages to ensure that the two types of actuators are coordinated and in place. This effectively eliminates the body attitude oscillation and lift fluctuation caused by asynchronous response, and significantly improves the riding comfort and driving safety of the sightseeing flying motorcycle. Attached Figure Description

[0012] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a flowchart of a method provided in an embodiment of the present invention. Detailed Implementation

[0014] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a method for adjusting the flight attitude of a sightseeing flying motorcycle according to the present invention. In the following description, different embodiments or different embodiments do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0015] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0016] The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0017] The following description, in conjunction with the accompanying drawings, details a specific scheme for adjusting the flight attitude of a sightseeing flying motorcycle provided by the present invention.

[0018] Please see Figure 1 The diagram illustrates a method flowchart for adjusting the flight attitude of a sightseeing flying motorcycle according to an embodiment of the present invention. The method includes the following steps: S1. Before the flying motorcycle transitions from hovering mode to level flight mode, a nonlinear dynamic model is constructed based on the actual tilt angle of its tilt mechanism, airspeed, and the current attitude angle of the aircraft measured by the inertial measurement unit. S2, during the transition of the flying motorcycle from hovering mode to level flight mode, monitors the actual tilt angle and its rate of change. When the actual tilt angle enters the preset critical tilt angle range, or the rate of change is greater than the preset tilt angle change rate threshold, it enters the feedforward compensation control mode. S3, in the feedforward compensation control mode, based on the nonlinear dynamic model, with the deviation between the current attitude angle and the target attitude angle and the remaining tilt stroke from the actual tilt angle to the target tilt angle during the mode transition as constraints, the control sequence in the time domain of the mode transition process is solved by rolling optimization, and the pitch channel compensation torque and lift channel compensation force used for mode transition are calculated. S4 maps the pitch channel compensation torque and lift channel compensation force to the tilt angle adjustment of the tilt mechanism and the speed adjustment of the independent rotor motor respectively through the force and torque distribution matrix, and makes the tilt mechanism and rotor motor respond and execute the corresponding adjustment actions simultaneously.

[0019] As one embodiment of the present invention, the step of constructing a nonlinear dynamic model based on the actual tilt angle of its tilt mechanism, airspeed, and the current attitude angle of the aircraft measured by the inertial measurement unit before the flying motorcycle transitions from hovering mode to level flight mode includes: Based on the actual tilt angle and airspeed of the tilt mechanism, and combined with the preset kinematic model of the tilt mechanism, the thrust direction and magnitude of the tilt mechanism acting on the aircraft under the current flight state are calculated to obtain the thrust vector matrix. Based on the aircraft's current attitude angle and airspeed, and combined with the preset aerodynamic coefficient model, the aerodynamic forces and aerodynamic moments acting on the aircraft under the current flight state are calculated, and the aerodynamic force matrix and aerodynamic moment matrix are obtained respectively. The current attitude angle includes pitch angle, roll angle and yaw angle. The thrust vector matrix, aerodynamic matrix, and preset gravity vector matrix are superimposed to construct a nonlinear dynamic model with the current attitude angle and airspeed as state variables and the tilt angle and the rotational speed of each rotor motor as control variables.

[0020] It should be noted that in the process of constructing the above nonlinear dynamic model, the kinematic model of the tilting mechanism describes the geometric mapping relationship between the tilting angle and the thrust vector direction. Those skilled in the art can establish the corresponding kinematic equations according to the specific configuration of the tilting mechanism of the flying motorcycle (such as the tilting angle range, tilting axis position, etc.).

[0021] The aerodynamic coefficient model can include the functional relationship or lookup table of lift coefficient, drag coefficient and torque coefficient as a function of attitude angle and airspeed. The specific coefficients can be pre-calibrated through computational fluid dynamics simulation.

[0022] By superimposing the thrust vector matrix, aerodynamic force matrix, and gravity vector matrix, the resultant force and resultant torque of the flying motorcycle during the mode transition process can be obtained. Combining this with the Newton-Euler equations, a nonlinear dynamic model can be derived, with the current attitude angle and airspeed as state variables and the tilt angle and the rotational speed of each rotor motor as control variables.

[0023] Those skilled in the art should understand that the differential equations of the state variables, namely attitude angle and airspeed, implicitly contain the kinematic relationship between attitude angle and angular velocity, as well as the dynamic relationship between airspeed and linear acceleration. This nonlinear dynamic model fully describes the dynamic behavior of the flying motorcycle during mode transitions, providing an accurate predictive basis for subsequent model predictive control.

[0024] In one embodiment of the present invention, the preset critical tilt angle range is determined through the following steps: During the ground test phase, the tilt mechanism is controlled to continuously tilt from the tilt angle corresponding to the standard hovering state to the tilt angle corresponding to the standard level flight state at a preset angular velocity, while collecting the current feedback signals of each rotor motor and the vibration acceleration signals of the airframe. Construct time-varying curves for current feedback signal and body vibration acceleration signal. Based on the time-varying curves, when the standard deviation of the current feedback signal exceeds a preset first critical value and the peak value of the body vibration acceleration signal exceeds a preset second critical value, record the tilt angle corresponding to that moment as the first critical angle. When the standard deviation of the current feedback signal falls below the preset third critical value, and the peak value of the body vibration acceleration signal falls below the preset fourth critical value, the tilt angle corresponding to that moment is recorded as the second critical angle. The angle range between the first critical angle and the second critical angle is determined as the preset critical tilt angle range.

[0025] It should be noted that, in this embodiment, the calibration principle of the critical tilt angle range is as follows: when the tilting mechanism of the flying motorcycle enters a certain tilt angle range, significant aerodynamic interference will occur between the rotor disk and the fuselage, causing a sharp change in the rotor motor load. This is manifested as an increase in the standard deviation of the rotor motor's current feedback signal, and at the same time, the fuselage vibration intensifies, manifested as an increase in the peak value of the fuselage's vibration acceleration signal. This tilt angle range is the unsteady aerodynamic range, which is also the critical range that needs to trigger feedforward compensation control. Among them, the standard deviation of the current feedback signal is used to characterize the severity of the motor load fluctuation, and the peak value of the vibration acceleration signal is used to characterize the intensity of the excitation on the fuselage structure.

[0026] In this embodiment, the preset first threshold, second threshold, third threshold and fourth threshold can be determined by statistical analysis of multiple sets of ground test data. Preferably, the average value of the standard deviation of the current feedback signal and the peak value of the vibration acceleration signal in multiple ground test data is taken and then doubled as the trigger threshold. The first critical angle corresponds to the initial boundary of entering the unsteady aerodynamic range, and the second critical angle corresponds to the final boundary of exiting the range. Due to the aerodynamic hysteresis effect, the first critical angle is usually smaller than the second critical angle, and the range between the two is the tilt angle range in which feedforward compensation control needs to be enabled.

[0027] In one embodiment of the present invention, the preset rate of change threshold is determined through the following steps: Real-time acquisition of the current load mass and ambient wind speed of the flying motorcycle; based on the load mass, the basic rate of change threshold of the tilt angle is calculated according to the preset mass-tilt angle mapping relationship. Based on the projection component of the ambient wind speed onto the tilt plane of the aircraft, the correction coefficient is calculated according to the preset wind speed-correction coefficient mapping relationship; The product of the basic rate of change threshold and the correction coefficient is determined as the preset tilt angle rate of change threshold.

[0028] It should be noted that in this embodiment, the load mass can be estimated by the integral value of the current of each rotor motor in the hovering state, or directly measured by the pressure sensor installed on the landing gear; the ambient wind speed can be collected in real time by an ultrasonic anemometer or a three-dimensional anemometer installed on the fuselage, and its projection component in the tilt plane can be calculated.

[0029] The principle of adaptively determining the rate of change threshold of the tilt angle is as follows: the greater the load mass of the flying motorcycle, the greater the moment of inertia of the whole machine, and the lower the maximum allowable tilt angle velocity, so as to avoid the body attitude divergence or structural overload due to excessive inertia; at the same time, the greater the ambient wind speed, the stronger the external aerodynamic interference, and the rate of change threshold should be appropriately increased to avoid false triggering.

[0030] The mass-rate of change threshold mapping relationship is preferably in the form of a linear inverse proportional function, a piecewise linear function, or an exponential decay function. The specific function parameters can be obtained by calibrating tilt bench experiments or flight test data under different load conditions. Preferably, the basic rate of change threshold when the airframe is unloaded is set to 30 / s, and when it is fully loaded it is set to 15 / s. The intermediate load is calculated by linear interpolation.

[0031] The wind speed-correction coefficient mapping relationship is preferably implemented using a proportional function or a piecewise threshold function. The range of the correction coefficient is usually set to be greater than or equal to 1. Preferably, when the projection component of the ambient wind speed on the tilt plane is less than 3 m / s, the correction coefficient is set to 1.0; when the projection component of the ambient wind speed on the tilt plane is between 3 m / s and 8 m / s, the correction coefficient is set to 1.3; and when the projection component of the ambient wind speed on the tilt plane is greater than or equal to 8 m / s, the correction coefficient is set to 1.6.

[0032] Those skilled in the art should understand that the specific parameters in the above mapping relationship can be adaptively adjusted according to the characteristics of different flying motorcycle models, and the method of determining them falls within the scope of routine experimental calibration.

[0033] In one embodiment of the present invention, the deviation between the current attitude angle and the target attitude angle, and the remaining tilt travel from the actual tilt angle to the target tilt angle during the mode transition are used as constraints. The setting of the constraints includes the following steps: The mode transition process is divided into three continuous stages in the time domain: the initial stage, the transition stage, and the approach stage. In the initial stage, the deviation between the actual tilt angle and the target tilt angle is greater than a preset first deviation value. In the transition stage, the deviation between the actual tilt angle and the target tilt angle is greater than a preset second deviation value but less than or equal to the preset first deviation value. In the approach stage, the deviation between the actual tilt angle and the target tilt angle is less than or equal to the preset second deviation value. In the initial stage, the constraint priority of the lift channel compensation force is set higher than that of the pitch channel compensation moment; During the transition phase, the constraint priority of the pitch channel compensation torque is set to be equal to that of the lift channel compensation force, and the remaining deviation between the actual tilt angle and the target tilt angle is used as the mandatory constraint condition. During the approach phase, the constraint priority of the pitch channel compensation torque is set higher than that of the lift channel compensation force, and the residual deviation between the actual tilt angle and the target tilt angle is used as the relaxation constraint condition. The smaller the residual deviation, the smaller the allowable rate of change of the pitch channel compensation torque.

[0034] It should be noted that, in this embodiment, the phased setting of constraints aims to solve the dynamic coordination problem between the two control objectives of maintaining altitude and attitude adjustment during mode transition. Specifically: In the initial stage, when the tilting has just begun, the flying motorcycle has not yet obtained sufficient wing lift compensation. At this time, preventing the fuselage from losing altitude is the primary task. Therefore, the constraint priority of the lift channel compensation force is set higher than the pitch channel compensation torque. During the transition phase, the flying motorcycle has already achieved a certain forward speed and the wings begin to generate lift. At this time, it is necessary to maintain altitude and adjust attitude at the same time. Therefore, the two are set to have equal priority, and the remaining tilting stroke is used as a mandatory constraint, that is, the tilting mechanism must be controlled to complete the tilting along the predetermined path and must not deviate arbitrarily. During the approach phase, the tilt is about to be completed. At this time, the main focus is on attitude accuracy. Therefore, the pitch priority is set higher than the lift priority, and the remaining deviation is used as a relaxation constraint. That is, the attitude angle is allowed to fluctuate within a certain range, but the rate of change of the compensation torque is limited to ensure that its convergence is smooth.

[0035] The first and second deviation values ​​can be preset according to the response characteristics of the tilt mechanism of the flying motorcycle and the comfort requirements of the driver. Preferably, the first deviation value is set to 70% of the total tilt stroke and the second deviation value is set to 20% of the total tilt stroke. The forced constraint is manifested in the introduction of hard constraints in the model predictive control process. If the hard constraint is violated, no feasible solution will be output. The relaxation constraint is manifested in the introduction of soft constraints in the model predictive control process. It is achieved by introducing relaxation variables and applying a penalty term in the cost function. The smaller the residual deviation between the actual tilt angle and the target tilt angle, the smaller the allowable rate of change of the pitch channel compensation torque.

[0036] Those skilled in the art should understand that the above priority can be achieved by adjusting the weights of each error term in the model prediction control cost function. The difference between mandatory constraints and relaxed constraints lies in whether or not relaxed variables and their penalty coefficients are introduced.

[0037] As one embodiment of the present invention, the process of solving the control sequence in the time domain of the mode transition process through rolling optimization further includes the following adaptive time domain adjustment step: During the mode transition process, the prediction time domain length and control time domain length are initialized separately in the time domain, and the sampling period is initialized to the basic sampling period, wherein the prediction time domain length is greater than the control time domain length; The actual tilt angle change rate and attitude angle acceleration are monitored in real time. When the actual tilt angle change rate is greater than the preset high-speed tilt threshold, or the acceleration of any attitude angle is greater than the preset attitude sudden change threshold, the control time domain length is shortened to 1 / 2 of the original length, and the sampling period is shortened to 1 / 2 of the original length. When the deviation between the actual tilt angle and the target tilt angle is less than the preset proximity threshold, and the deviation between all attitude angles and their corresponding target values ​​is less than the preset steady-state threshold, the prediction time domain length will be extended to twice the original length, and the sampling period will be returned to the basic sampling period. Based on the adjusted prediction time domain length, control time domain length, and sampling period, a cost function for rolling optimization is constructed, and the control sequence is solved at each sampling time point.

[0038] It should be noted that in this embodiment, when the rate of change of the actual tilt angle is detected to be greater than the preset high-speed tilt threshold, or the acceleration of any attitude angle is greater than the preset attitude change threshold, it indicates that the aircraft is in a state of violent dynamic change. At this time, the controllers of each actuator (i.e., the tilt mechanism and the rotor motor) need to have a faster response capability. Therefore, the control time domain length and sampling period are shortened to half of the original to reduce the number of decision variables in the optimization problem, speed up the solution speed, and increase the update frequency of control commands. When the deviation between the actual tilt angle and the target tilt angle is less than the preset approach threshold, it indicates that the aircraft has entered the steady-state approach phase. At this time, the controller needs to have a relatively longer prediction capability. Therefore, the prediction time domain length is extended to twice the original length, and the sampling period is restored to the basic value to achieve smooth convergence and reduce the computational burden.

[0039] Preferably, the initial value of the prediction time domain length can be set to 20 sampling periods, the initial value of the control time domain length can be set to 5 sampling periods, and the basic sampling period can be set to 20ms. The above parameters can be adjusted according to the actual dynamic characteristics of the flying motorcycle.

[0040] The specific values ​​of the high-speed tilt threshold, attitude change threshold, approach threshold, and steady-state threshold can be obtained by calibration using flight test data under typical operating conditions. Preferably, the high-speed tilt threshold is set to 30 / s, the attitude change threshold is set to 50 / s, the approach threshold is set to 5, and the steady-state threshold is set to 1.

[0041] In one embodiment of the present invention, after calculating the pitch channel compensation torque and lift channel compensation force used for mode conversion, the method further includes a step of decoupling the two to obtain an equivalent control quantity: Based on the nonlinear dynamics model, the transfer functions of tilt angle to pitch channel compensation torque and to lift channel compensation force are established, as are the transfer functions of each rotor motor speed to pitch channel compensation torque and to lift channel compensation force. Based on the nonlinear dynamic model, the coupling index between each tilting mechanism and each rotor motor is calculated by the relative gain array method. When the coupling index is greater than the preset decoupling threshold, it is determined that there is strong coupling between the pitch channel and the lift channel. When strong coupling is determined to exist and the remaining tilt stroke is greater than the preset decoupling stroke, the pitch channel compensation torque and lift channel compensation force are decoupled and calculated using a static decoupling matrix to obtain the decoupled equivalent pitch control quantity and equivalent lift control quantity. When strong coupling is determined to exist and the remaining tilt stroke is less than or equal to the preset decoupling stroke, a dynamic decoupling network is used instead of a static decoupling matrix to perform decoupling calculations on the pitch channel compensation torque and lift channel compensation force, thereby obtaining the decoupled equivalent pitch control quantity and equivalent lift control quantity. The equivalent pitch control and equivalent lift control values ​​replace the original pitch channel compensation torque and lift channel compensation force, respectively, and are used as inputs for subsequent steps.

[0042] It should be noted that during the mode transition of the flying motorcycle, the change in tilt angle not only generates pitching moment, but also affects the angle of the rotor disk relative to the relative airflow, thus changing the lift. At the same time, the change in rotor speed not only changes the lift, but also generates additional pitching moment due to the gyro effect and changes in disk load. This bidirectional coupling can cause mutual interference of controller commands and reduce control quality. Therefore, in this embodiment, the decoupling threshold is preferably set to 1.5. The coupling index is calculated by the relative gain array method. When it is 1.5, it is determined that strong coupling exists.

[0043] In this embodiment, the static decoupling matrix is ​​obtained by inverting the steady-state gain matrix near the current operating point. It is suitable for stages with a large remaining tilt stroke, where the dynamic changes of the system are relatively smooth, and static decoupling is sufficient to meet the requirements with low computational cost. The decoupling stroke is preferably set to 10% of the total tilt stroke. That is, when the remaining stroke is less than 10% of the total tilt stroke, the system switches to the dynamic decoupling network. The dynamic decoupling network adopts the form of a transfer function matrix, which can compensate for the differences in coupling characteristics at different frequencies. It is suitable for stages with a small remaining tilt stroke, where more refined decoupling is required to ensure steady-state accuracy. The parameters of both the static decoupling matrix and the dynamic decoupling network can be calculated based on the nonlinear dynamic model after linearization at the nominal operating point, which is a conventional technique in the design of multivariable control systems.

[0044] The equivalent pitch control and equivalent lift control obtained after decoupling replace the original compensation quantities as inputs for subsequent allocation steps, so that the subsequent force and torque allocation matrix faces the decoupled control commands, thereby simplifying the allocation logic and improving control accuracy.

[0045] In one embodiment of the present invention, the force and moment distribution matrix is ​​updated online through the following steps: Based on the nominal geometric and aerodynamic parameters of the flying motorcycle, initialize the reference allocation matrix for the tilt mechanism and rotor motor, with a dimension of (2 = number of tilt mechanisms and number of rotor motors). During the time window when the flying motorcycle is hovering and no attitude adjustment is performed, excitation signals with an amplitude smaller than the preset disturbance threshold are applied to each tilt mechanism and each rotor motor, and the actual pitch torque change and lift change generated by the airframe are collected simultaneously. Based on the excitation signal, pitch moment change, and lift change, the force and moment distribution matrix at the current moment is estimated online using a recursive least squares algorithm. Calculate the deviation between the force and torque allocation matrix and the reference allocation matrix. When the deviation exceeds the preset matrix update threshold, update the currently used force and torque allocation matrix using a weighted average method.

[0046] It should be noted that in this embodiment, the reference allocation matrix is ​​pre-calculated based on the nominal geometric parameters (such as the lever arm length of the tilting mechanism and the rotor installation position) and nominal aerodynamic parameters (such as the blade lift coefficient and drag coefficient) of the flying motorcycle, and is used to reflect the control allocation relationship under ideal conditions.

[0047] The excitation signal is preferably a sinusoidal sweep frequency signal or a pseudo-random binary sequence. Its signal amplitude must be less than the preset disturbance threshold, preferably not exceeding 5% of the rated control quantity, to ensure that the attitude fluctuation of the flying motorcycle is within a safe range during the excitation process and to minimize the impact on riding comfort.

[0048] The preferred weighted average method is to use the following formula: ; Among them, A new For the updated force and moment assignment matrix, A est A is the force and moment distribution matrix estimated online by the recursive least squares algorithm. old The force and moment allocation matrix currently in use is , and the update coefficients are , with values ​​ranging from 0.1 to 0.3, used to smoothly estimate the impact of noise while ensuring tracking performance.

[0049] Those skilled in the art should understand that, since the flying motorcycle is in a strongly nonlinear region when performing large-scale attitude adjustments, the online update step of the force and torque distribution matrix is ​​only performed in the hovering state and within the time window when there is no attitude adjustment. At this time, the system approximately satisfies the linear time-invariant assumption to ensure the convergence and estimation accuracy of the recursive least squares algorithm.

[0050] In one embodiment of the present invention, the step of mapping the pitch channel compensation torque and the lift channel compensation force to the tilt angle adjustment amount of the tilt mechanism and the speed adjustment amount of the independent rotor motor respectively through the force and torque distribution matrix includes: Real-time data collection of the current tilt angle of each tilting mechanism and the current speed, current and temperature of each rotor motor; The health index of each tilting mechanism is calculated based on the distance between the current position of each tilting mechanism and the preset limit boundary. The health index of each rotor motor is calculated based on the ratio of the current current to the rated current of each rotor motor. The value range of each health index is [0, 1]. When the absolute value of the pitch channel compensation torque is greater than the preset pitch adjustment threshold, the pitch channel compensation torque is allocated accordingly based on the normalized value of the health index of each tilt mechanism and rotor motor. When the ratio of the lift channel compensation force to the current lift exceeds the preset lift adjustment threshold, the lift channel compensation force is allocated accordingly based on the normalized value of the health index of each rotor motor, while keeping the tilt angle of each tilting mechanism unchanged.

[0051] It should be noted that in this embodiment, the health index of the tilting mechanism is calculated based on the distance between its current tilting angle and the preset limit boundary (such as the mechanical limit angle or the software limit angle). The closer the distance, the closer the tilting mechanism is to the limit, and the lower the health index. The health index of the rotor motor is calculated based on the ratio of its current current to its rated current. The closer the ratio is to 1, the closer the rotor motor is to its rated load, and the lower the health index.

[0052] When the absolute value of the pitch channel compensation torque exceeds the pitch adjustment threshold, preferably exceeding 5 Nm, the health index of all tilt mechanisms and rotor motors is normalized and used as a weight. The compensation torque is then distributed to each actuator according to the weight, so that the actuator with high health can undertake more control tasks and the actuator with low health can undertake fewer control tasks. When the ratio of the lift channel compensation force to the current lift exceeds the lift adjustment threshold, preferably exceeding 10% of the current lift, it indicates that a larger lift adjustment is needed. In this case, the health index of each rotor motor is normalized and used as a weight for allocation, while keeping the tilt angle of each tilt mechanism unchanged, so as to avoid introducing additional pitch torque interference due to changes in the tilt angle during the lift adjustment process.

[0053] The normalization process involves dividing the health index of each implementing agency by the sum of the health indices of all implementing agencies, so that the sum of the weights of each implementing agency after normalization is 1.

[0054] In one embodiment of the present invention, the step of causing the tilting mechanism and the rotor motor to respond simultaneously and perform corresponding adjustment actions includes: Calculate the estimated action time required for the tilt mechanism to perform the tilt angle adjustment, and the estimated response time required for the rotor motor to perform the speed adjustment; When the difference between the estimated action time and the estimated response time is less than the preset synchronization allowable deviation, execution commands are issued to the tilting mechanism and the rotor motor simultaneously. When the estimated action time is greater than the estimated response time, and the absolute value of the difference between the two is greater than the first compensation threshold, the tilt mechanism is started before the rotor motor. At the same time, the speed adjustment amount is decomposed into a pre-adjustment component and a main adjustment component. When the tilt mechanism completes 50% of the tilt angle adjustment amount, the rotor motor is instructed to execute the pre-adjustment component. When the tilt mechanism completes the entire tilt angle adjustment amount, the rotor motor is instructed to execute the main adjustment component. When the estimated action time is less than the estimated response time, and the absolute value of the difference between the two is greater than the second compensation threshold, the rotor motor is started before the tilting mechanism. When the rotor motor completes 90% of the speed adjustment, the tilting mechanism is instructed to perform the tilt angle adjustment.

[0055] It should be noted that in this embodiment, the estimated action time is calculated by dividing the tilt angle adjustment amount by the rated angular velocity of the tilting mechanism. For example, when the tilt angle adjustment amount is 10 and the rated angular velocity is 20 / s, the estimated action time is 0.5s. The estimated response time is determined based on the step response rise time of the rotor motor, which is usually defined as the time required to rise from 10% of the target speed to 90% of the target speed. The specific value can be pre-calibrated through offline testing. The preset synchronization allowable deviation is preferably set to 0.05s, which is used to determine whether the response times of the two types of actuators are close enough without the need for timing compensation.

[0056] When the estimated action time is greater than the estimated response time, and the absolute value of the difference between the two is greater than the first compensation threshold, it is considered that the tilting mechanism is significantly slower than the rotor motor. In this case, the tilting mechanism is started in advance, and the rotor motor speed adjustment is decomposed into a pre-adjustment component (e.g., 20%~30% of the total adjustment) and a main adjustment component (total adjustment minus the pre-adjustment component). The pre-adjustment component is executed when the tilting is halfway complete to partially compensate for the lift change, and the main adjustment component is executed when the tilting is fully completed to achieve the final target speed, thereby achieving smooth coordination between lift and pitch moment. The first compensation threshold is preferably set to 0.1s.

[0057] When the estimated action time is less than the estimated response time, and the absolute value of the difference between the two is greater than the second compensation threshold, it is considered that the rotor motor is significantly slower than the tilting mechanism. In this case, the rotor motor is started in advance, and the tilting mechanism is started after the rotor motor has reached 90% of its speed. The remaining 10% speed adjustment can be completed during the tilting process to avoid delaying the tilting timing due to waiting for the motor to be fully in place. The second compensation threshold is preferably set to 0.1s.

[0058] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for adjusting the flight attitude of a sightseeing flight motorcycle, characterized by comprising the steps of: detecting the attitude of the motorcycle; and adjusting the attitude of the motorcycle based on the detected attitude. The method includes: S1. Before the flying motorcycle transitions from hovering mode to level flight mode, a nonlinear dynamic model is constructed based on the actual tilt angle of its tilt mechanism, airspeed, and the current attitude angle of the aircraft measured by the inertial measurement unit. S2, during the transition of the flying motorcycle from hovering mode to level flight mode, the actual tilt angle and its rate of change are monitored. When the actual tilt angle enters the preset critical tilt angle range, or the rate of change is greater than the preset tilt angle change rate threshold, the feedforward compensation control mode is entered. S3, under the feedforward compensation control mode, based on the nonlinear dynamic model, with the deviation between the current attitude angle and the target attitude angle and the remaining tilt stroke from the actual tilt angle to the target tilt angle during the mode conversion process as constraints, the control sequence in the time domain of the mode conversion process is solved by rolling optimization, and the pitch channel compensation torque and lift channel compensation force used for mode conversion are calculated. S4, the pitch channel compensation torque and lift channel compensation force are mapped to the tilt angle adjustment amount of the tilt mechanism and the speed adjustment amount of the independent rotor motor respectively through the force and torque distribution matrix, and the tilt mechanism and rotor motor respond simultaneously and execute the corresponding adjustment actions.

2. The method for adjusting the flight attitude of a sightseeing flying motorcycle according to claim 1, characterized in that: The steps for constructing a nonlinear dynamic model of the flying motorcycle before it transitions from hovering mode to level flight mode include: (1) The actual tilt angle of its tilting mechanism, the airspeed, and the current attitude angle of the aircraft measured by the inertial measurement unit. Based on the actual tilt angle of the tilt mechanism and the airspeed, and combined with the preset kinematic model of the tilt mechanism, the thrust direction and magnitude of the tilt mechanism acting on the aircraft under the current flight state are calculated to obtain the thrust vector matrix. Based on the current attitude angle and airspeed of the aircraft, and combined with the preset aerodynamic coefficient model, the aerodynamic forces and aerodynamic moments acting on the aircraft under the current flight state are calculated, and the aerodynamic force matrix and aerodynamic moment matrix are obtained respectively. The current attitude angle includes pitch angle, roll angle and yaw angle. The thrust vector matrix, the aerodynamic force matrix, and the preset gravity vector matrix are superimposed to construct a nonlinear dynamic model with the current attitude angle and the airspeed as state variables and the tilt angle and the rotational speed of each rotor motor as control variables.

3. The method for adjusting the flight attitude of a sightseeing flying motorcycle according to claim 1, characterized in that: The preset critical tilt angle range is determined through the following steps: During the ground test phase, the tilt mechanism is controlled to continuously tilt from the tilt angle corresponding to the standard hovering state to the tilt angle corresponding to the standard level flight state at a preset angular velocity, while collecting the current feedback signals of each rotor motor and the vibration acceleration signals of the airframe. Construct time-varying curves for the current feedback signal and the body vibration acceleration signal. Based on the time-varying curves, when the standard deviation of the current feedback signal exceeds a preset first critical value and the peak value of the body vibration acceleration signal exceeds a preset second critical value, record the tilt angle corresponding to that moment as the first critical angle. When the standard deviation of the current feedback signal falls below the preset third critical value, and the peak value of the body vibration acceleration signal falls below the preset fourth critical value, the tilt angle corresponding to that moment is recorded as the second critical angle. The angle interval between the first critical angle and the second critical angle is determined as the preset critical tilt angle range.

4. The method for adjusting the flight attitude of a sightseeing flying motorcycle according to claim 1, characterized in that: The preset rate of change threshold is determined through the following steps: The current load and ambient wind speed of the flying motorcycle are acquired in real time. Based on the load, the basic rate of change threshold of the tilt angle is calculated according to the preset mass-tilt angle mapping relationship. Based on the projection component of the ambient wind speed onto the tilt plane of the aircraft, the correction coefficient is calculated according to the preset wind speed-correction coefficient mapping relationship; The product of the basic rate of change threshold and the correction coefficient is determined as the preset tilt angle rate of change threshold.

5. The method for adjusting the flight attitude of a sightseeing flying motorcycle according to claim 1, characterized in that: The constraints are defined by the deviation between the current attitude angle and the target attitude angle, and the remaining tilt travel from the actual tilt angle to the target tilt angle during the mode transition. The setting of the constraints includes the following steps: The modal conversion process is divided into three consecutive stages in the time domain: the initial stage, the transition stage, and the approach stage. The initial stage corresponds to a deviation between the actual tilt angle and the target tilt angle that is greater than a preset first deviation value. The transition stage corresponds to a deviation between the actual tilt angle and the target tilt angle that is greater than a preset second deviation value and less than or equal to the preset first deviation value. The approach stage corresponds to a deviation between the actual tilt angle and the target tilt angle that is less than or equal to the preset second deviation value. In the initial stage, the constraint priority of the lift channel compensation force is set higher than that of the pitch channel compensation moment; During the transition phase, the constraint priority of the pitch channel compensation torque and the constraint priority of the lift channel compensation force are set to be equal, and the remaining deviation between the actual tilt angle and the target tilt angle is used as the mandatory constraint condition. During the approach phase, the constraint priority of the pitch channel compensation torque is set higher than that of the lift channel compensation force, and the residual deviation between the actual tilt angle and the target tilt angle is used as the relaxation constraint condition, wherein the smaller the residual deviation, the smaller the allowable rate of change of the pitch channel compensation torque.

6. The method for adjusting the flight attitude of a sightseeing flying motorcycle according to claim 1, characterized in that: The process of solving the control sequence in the time domain of the mode transition process through rolling optimization also includes the following adaptive time-domain adjustment steps: In the modality conversion process, the prediction time domain length and the control time domain length are initialized respectively in the time domain, and the sampling period is initialized to the basic sampling period, wherein the prediction time domain length is greater than the control time domain length; The rate of change of the actual tilt angle and the acceleration of the attitude angle are monitored in real time. When the rate of change of the actual tilt angle is greater than the preset high-speed tilt threshold, or the acceleration of any attitude angle is greater than the preset attitude sudden change threshold, the control time domain length is shortened to 1 / 2 of the original length, and the sampling period is shortened to 1 / 2 of the original length. When the deviation between the actual tilt angle and the target tilt angle is less than a preset proximity threshold, and the deviation between all attitude angles and their corresponding target values ​​is less than a preset steady-state threshold, the prediction time domain length is extended to twice the original length, and the sampling period is returned to the basic sampling period. Based on the adjusted prediction time domain length, control time domain length, and sampling period, a cost function for the rolling optimization is constructed, and the control sequence is solved at each sampling time point.

7. The method for adjusting the flight attitude of a sightseeing flying motorcycle according to claim 1, characterized in that: The calculation of the pitch channel compensation torque and lift channel compensation force used for mode conversion also includes a step of decoupling the two to obtain the equivalent control quantity: Based on the aforementioned nonlinear dynamic model, the transfer functions of tilt angle to pitch channel compensation torque and to lift channel compensation force are established, as are the transfer functions of each rotor motor speed to pitch channel compensation torque and to lift channel compensation force. Based on the nonlinear dynamic model, the coupling index between each tilting mechanism and each rotor motor is calculated using the relative gain array method. When the coupling index is greater than the preset decoupling threshold, it is determined that there is strong coupling between the pitch channel and the lift channel. When it is determined that strong coupling exists and the remaining tilt stroke is greater than the preset decoupling stroke, the pitch channel compensation torque and lift channel compensation force are decoupled and calculated using a static decoupling matrix to obtain the decoupled equivalent pitch control quantity and equivalent lift control quantity. When strong coupling is determined to exist and the remaining tilt stroke is less than or equal to the preset decoupling stroke, a dynamic decoupling network is used instead of a static decoupling matrix to perform decoupling calculations on the pitch channel compensation torque and lift channel compensation force, thereby obtaining the decoupled equivalent pitch control quantity and equivalent lift control quantity. The equivalent pitch control and equivalent lift control values ​​replace the original pitch channel compensation torque and lift channel compensation force, respectively, and are used as inputs for subsequent steps.

8. The method for adjusting the flight attitude of a sightseeing flying motorcycle according to claim 1, characterized in that: The force and moment distribution matrix is ​​updated online through the following steps: Based on the nominal geometric and aerodynamic parameters of the flying motorcycle, initialize the reference allocation matrix for the tilt mechanism and rotor motor, with a dimension of (2 = number of tilt mechanisms and number of rotor motors). During the time window when the flying motorcycle is hovering and no attitude adjustment is performed, excitation signals with an amplitude smaller than the preset disturbance threshold are applied to each tilt mechanism and each rotor motor, and the actual pitch torque change and lift change generated by the airframe are collected simultaneously. Based on the excitation signal, the pitch moment change, and the lift change, the force and moment distribution matrix at the current moment is estimated online using a recursive least squares algorithm. The deviation between the force and torque allocation matrix and the reference allocation matrix is ​​calculated. When the deviation exceeds a preset matrix update threshold, the currently used force and torque allocation matrix is ​​updated using a weighted average method.

9. The method for adjusting the flight attitude of a sightseeing flying motorcycle according to claim 1, characterized in that: The step of mapping the pitch channel compensation torque and lift channel compensation force to the tilt angle adjustment of the tilt mechanism and the speed adjustment of the independent rotor motor respectively through the force and torque distribution matrix includes: Real-time data collection of the current tilt angle of each tilting mechanism and the current speed, current and temperature of each rotor motor; The health index of each tilting mechanism is calculated based on the distance between the current position of each tilting mechanism and the preset limit boundary. The health index of each rotor motor is calculated based on the ratio of the current current to the rated current of each rotor motor. The value range of each health index is [0, 1]. When the absolute value of the pitch channel compensation torque is greater than the preset pitch adjustment threshold, the pitch channel compensation torque is allocated accordingly, with the normalized value of the health index of each tilt mechanism and rotor motor as the weight. When the ratio of the lift channel compensation force to the current lift exceeds the preset lift adjustment threshold, the lift channel compensation force is allocated accordingly based on the normalized value of the health index of each rotor motor, while keeping the tilt angle of each tilting mechanism unchanged.

10. The method for adjusting the flight attitude of a sightseeing flying motorcycle according to claim 1, characterized in that: The steps to make the tilting mechanism and the rotor motor respond simultaneously and perform the corresponding adjustment actions include: Calculate the estimated action time required for the tilt mechanism to execute the tilt angle adjustment, and the estimated response time required for the rotor motor to execute the speed adjustment; When the difference between the estimated action time and the estimated response time is less than the preset synchronization allowable deviation, an execution command is issued to both the tilting mechanism and the rotor motor simultaneously. When the estimated action time is greater than the estimated response time, and the absolute value of the difference between the two is greater than the first compensation threshold, the tilt mechanism is started before the rotor motor. At the same time, the speed adjustment amount is decomposed into a pre-adjustment component and a main adjustment component. When the tilt mechanism completes 50% of the tilt angle adjustment amount, the rotor motor is instructed to execute the pre-adjustment component. When the tilt mechanism completes the entire tilt angle adjustment amount, the rotor motor is instructed to execute the main adjustment component. When the estimated action time is less than the estimated response time, and the absolute value of the difference between the two is greater than the second compensation threshold, the rotor motor is started before the tilting mechanism. When the rotor motor completes 90% of the speed adjustment, the tilting mechanism is instructed to perform the tilt angle adjustment.

Images