A method and device for suppressing vertical turbulence of a multi-control surface aircraft

Abstract

The present application provides a method and device for suppressing vertical turbulence in a multi-control surface aircraft, belonging to the field of automatic flight control technology. After the aircraft is connected to the altitude hold function, the method first obtains a vertical velocity error signal; then performs signal separation on the vertical velocity error signal to obtain a low-frequency signal and a high-frequency signal; determines a pitch moment instruction based on the low-frequency signal; determines a direct force instruction based on the high-frequency signal; and then generates a deflection angle instruction for each rudder based on the direct force instruction and the pitch moment instruction; finally, outputs the deflection angle instruction of each rudder to a servo controller, so that the servo controller drives the rudder to deflect, completing the control of the aircraft, and can enhance the aircraft's ability to suppress vertical turbulence and improve flight quality. This method can achieve vertical turbulence suppression by adding signal separation, turbulence suppression control, and rudder distribution processes to the original control law, and has high engineering practical value.

Description

Technical Field

[0001] The present application belongs to the field of automatic flight control technology, and specifically relates to a method and device for suppressing vertical turbulence of a multi-control surface aircraft. Background Art

[0002] Drones flying in the atmosphere are subject to turbulence, which can significantly disrupt their attitude and trajectory, placing significant dynamic loads on them. Conventional fixed-wing aircraft, limited by the number of control surfaces, cannot simultaneously control force and torque. The emergence of new multi-control surface aircraft requires that multiple control surfaces be combined and allocated to achieve decoupled force and torque control. This allows the aircraft to accurately suppress the effects of turbulence, significantly reducing dynamic loads during flight and extending the aircraft's lifespan. Furthermore, this approach can effectively improve ride comfort for such manned aircraft.

[0003] Figure 1 This is the architecture of a traditional aircraft altitude hold controller. In this controller, the altitude hold control law generates a vertical speed command, which is transmitted to the vertical speed hold control law, and then the pitch angle command is calculated, which enters the pitch angle control law. Finally, the deflection of the elevator surface is calculated to generate a pitch torque to control the aircraft to maintain altitude. This control law architecture has a certain inhibitory effect on vertical turbulence by referring to vertical speed control, but the frequency of turbulence tends to increase, and the bandwidth of the automatic flight vertical speed loop has attenuated to a lower value, and the response to high-frequency disturbances is limited. Summary of the Invention

[0004] This application provides a method and device for suppressing vertical turbulence in a multi-control surface aircraft, which solves the problem in related technologies that high-frequency turbulence cannot be effectively suppressed due to the low bandwidth of the vertical velocity loop of automatic flight. The technical solution is as follows:

[0005] In a first aspect, a method for suppressing vertical turbulence of a multi-control surface aircraft is provided, comprising:

[0006] When the aircraft is in altitude hold mode, the vertical velocity error signal is obtained.

[0007] Perform signal separation on the vertical velocity error signal to obtain a low-frequency signal and a high-frequency signal;

[0008] determining a pitch moment command based on the low-frequency signal;

[0009] Determine direct force command based on high frequency signal;

[0010] Generate the deflection angle command of each rudder surface according to the direct force command and the pitching moment command;

[0011] The deflection angle instructions of each rudder surface are output to the servo controller, so that the servo controller drives the rudder surface to deflect.

[0012] Optionally, the aircraft has K pairs of control surfaces, K is greater than 2, and a deflection angle instruction for each control surface is generated according to a direct force instruction and a pitch moment instruction, including:

[0013] When K is an integer multiple of 2, a deflection angle command for each rudder surface is generated according to a first calculation method. The first calculation method is as follows: K pairs of rudder surfaces are grouped, with two pairs of rudder surfaces as one group, and the required direct force and pitching moment are evenly distributed to determine the deflection angle of each pair of rudder surfaces, so that the deflection angles of the two rudder surfaces in each pair are the same;

[0014] When K is equal to (an integer multiple of 2+1), a pair of control surfaces that meet the preset conditions is removed, and a deflection angle instruction for each control surface is generated according to the first calculation method.

[0015] Optionally, the preset condition is: the lift increment F generated by the pair of rudder surfaces deflecting 1 degree at the trim point δi Minimum.

[0016] Optionally, obtaining a vertical velocity error signal includes:

[0017] According to the received preset course altitude command HC, the altitude signal H from the sensor system, and the vertical speed signal VS from the sensor system, the vertical speed error signal VS_err is calculated. The calculation formula is:

[0018] VS_err = KH × (HC - H) - VS

[0019] Where KH is the control gain.

[0020] Optionally, performing signal separation on the vertical velocity error signal to obtain a low-frequency signal and a high-frequency signal includes:

[0021] A low-pass filter is used to perform low-pass filtering on the vertical velocity error signal to obtain a low-frequency signal;

[0022] The difference between the vertical velocity error signal and the low-frequency signal is used as the high-frequency signal.

[0023] Optionally, the cutoff frequency of the low-pass filter is determined according to a pitch short-period cutoff frequency value in the body characteristics of the aircraft under maximum dynamic pressure.

[0024] Optionally, determining the pitch moment command according to the low-frequency signal includes:

[0025] Generate a pitch angle command according to the low-frequency signal;

[0026] According to the pitch angle command, the pitch moment command is determined by the pitch attitude control law.

[0027] Optionally, determining a direct force command based on the high-frequency signal includes:

[0028] According to the high-frequency signal, the proportional plus integral control channel is used to generate direct force instructions.

[0029] In a second aspect, a vertical turbulence suppression device for a multi-control surface aircraft is provided, comprising:

[0030] Get modules for:

[0031] After the aircraft is in the altitude hold mode, the vertical velocity error signal is obtained.

[0032] Perform signal separation on the vertical velocity error signal to obtain a low-frequency signal and a high-frequency signal;

[0033] determining a pitch moment command based on the low-frequency signal;

[0034] Determine direct force command based on high frequency signal;

[0035] Generate the deflection angle command of each rudder surface according to the direct force command and the pitching moment command;

[0036] Output modules for:

[0037] The deflection angle instructions of each rudder surface are output to the servo controller, so that the servo controller drives the rudder surface to deflect.

[0038] Optionally, the aircraft has K pairs of control surfaces, K is greater than 2, and the acquisition module is specifically configured to:

[0039] When K is an integer multiple of 2, a deflection angle command for each rudder surface is generated according to a first calculation method. The first calculation method is as follows: K pairs of rudder surfaces are grouped, with two pairs of rudder surfaces forming one group, and the required direct force and pitching moment are evenly distributed to determine the deflection angle of each pair of rudder surfaces, so that the deflection angles of the two rudder surfaces in each pair are the same;

[0040] When K is equal to (an integer multiple of 2+1), a pair of rudder surfaces that meet the preset conditions is removed, and a deflection angle instruction for each rudder surface is generated according to the first calculation method.

[0041] After the aircraft is connected to the altitude hold function, the present application first obtains a vertical velocity error signal; then performs signal separation on the vertical velocity error signal to obtain a low-frequency signal and a high-frequency signal; determines a pitch moment command based on the low-frequency signal; determines a direct force command based on the high-frequency signal; and then generates a deflection angle command for each rudder surface based on the direct force command and the pitch moment command; finally, outputs the deflection angle command of each rudder surface to the servo controller, so that the servo controller drives the rudder surface to deflect, thereby completing the control of the aircraft, and can enhance the aircraft's ability to suppress vertical turbulence and improve flight quality. This method adds signal separation, turbulence suppression control, and rudder surface allocation processes to the original control law to achieve vertical turbulence suppression, and has high engineering practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram of a conventional aircraft longitudinal automatic flight controller;

[0043] Figure 2 A schematic diagram of the vertical turbulence suppression process based on a multi-control surface aircraft provided in an embodiment of the present application;

[0044] Figure 3 A flow chart of a signal separation algorithm provided in an embodiment of the present application;

[0045] Figure 4 A schematic diagram of the turbulence suppression control process provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] The present application is further described in detail below through specific implementation methods and drawings.

[0047] In this application, when the aircraft's altitude hold function is engaged, the altitude error is transmitted to the vertical velocity control law through the altitude control law. It is then combined with the vertical velocity feedback to generate a vertical velocity error signal. The vertical velocity error signal is then separated and processed to produce two signals: a low-frequency component and a high-frequency component. The low-frequency signal is used to generate a pitch angle command through the vertical velocity control law, which in turn generates a pitch moment command through the pitch attitude loop. The high-frequency signal is used to calculate a direct force command through the turbulence suppression control algorithm. Subsequently, based on the pitch moment command and direct force command, the control surface allocation algorithm is used to determine the deflection angle commands for each control surface. Finally, the flight control computer outputs the calculated deflection angle commands for each control surface to the servo controller, completing aircraft control.

[0048] The present application provides a flow chart of a method for suppressing vertical turbulence in a multi-control surface aircraft. The method is executed by a flight control computer. Specifically, the method may include the following steps:

[0049] Step 1: When the aircraft is in altitude hold mode, obtain the vertical velocity error signal.

[0050] The altitude hold function refers to the function of keeping the aircraft flying at a preset altitude.

[0051] like Figure 2 As shown in the figure, the flight control computer on the UAV calculates the vertical speed error signal VS_err based on the received preset route altitude command HC, the altitude signal H from the sensor system, and the vertical speed signal VS from the sensor system. The calculation formula is as follows:

[0052] VS_err = KH × (HC - H) - VS

[0053] Where KH is the control gain.

[0054] Step 2: Perform signal separation on the vertical velocity error signal to obtain low-frequency signal and high-frequency signal.

[0055] like Figure 3 As shown, the flight control computer passes the vertical speed error signal VS_err generated in step 1 through a low-pass filter to directly generate a low-frequency signal LF_VS_err; after obtaining the low-frequency signal LF_VS_err, the difference between the vertical speed error signal VS_err and the low-frequency signal LF_VS_err is used as the high-frequency signal HF_VS_err, that is, the high-frequency signal HF_VS_err is obtained by making a difference between the vertical speed error signal VS_err and the low-frequency signal LF_VS_err.

[0056] The cutoff frequency of the low-pass filter may be determined based on the short-period pitch cutoff frequency value in the aircraft's body characteristics at maximum dynamic pressure. For example, the cutoff frequency of the low-pass filter may be equal to the short-period pitch cutoff frequency value in the aircraft's body characteristics at maximum dynamic pressure + 5 rad / s.

[0057] Step 3: Generate a pitch angle command based on the low-frequency signal LF_VS_err generated in step 2, and then determine the pitch moment command through the pitch angle command.

[0058] This step uses the maneuver control algorithm to generate the pitch angle command.

[0059] like Figure 2 As shown, the low-frequency signal LF_VS_err generated by step 2 generates a pitch angle command through the proportional-integral vertical velocity control law, and then generates a pitch moment command through the pitch attitude control law. The pitch moment command is the required pitch moment M ref .

[0060] The proportional-integral vertical velocity control law and the pitch attitude control law can refer to the relevant technologies and will not be described in detail here.

[0061] Step 4: Determine the direct force command based on the high-frequency signal HF_VS_err generated in step 2.

[0062] This step determines the direct force instruction through the turbulence suppression control algorithm. The direct force instruction is the required direct force F. ref .

[0063] like Figure 4 As shown, the high-frequency signal HF_VS_err generated by step 2 can generate a direct force command through a proportional plus integral control channel.

[0064] To ensure that its authority does not affect normal flight, the integrator limiter used in the proportional plus integral control channel needs to be simulated based on the turbulence intensity allowed for the aircraft's takeoff. For example, under certain operating conditions, the aircraft's maximum maneuvering rudder is 10 degrees, and the aircraft's maximum control surface deflection under these conditions is 15 degrees. If simulations show that at a certain turbulence intensity, the control surface authority required for turbulence suppression exceeds the normal flight rudder margin (i.e., 15-10 = 5 degrees), the integrator limiter can be limited to 5 degrees to prevent impacting normal maneuvering.

[0065] Step 5: Generate the deflection angle command of each control surface according to the direct force command and the pitching moment command.

[0066] The required direct force F generated by steps 3 and 4 ref and pitching moment M ref , the deflection angle instruction of a single rudder is generated by the rudder allocation algorithm, and the deflection angle instruction is the deflection angle δ i The rudder surface allocation algorithm is as follows:

[0067] Assume that an aircraft has K pairs of control surfaces, and K is greater than or equal to 2. A pair of control surfaces refers to two control surfaces symmetrically distributed relative to the longitudinal axis of the aircraft. i The deflection angle of the ith pair of rudder surfaces is represented by F and the increment of lift and pitch moment generated by the deflection of the rudder surfaces by 1 degree at the trim point are represented by F and F respectively. δi and M δi Indicates that the direct force increment and pitch moment increment generated by the rudder deflection are linear. At this time, if a required direct force F is required ref and pitching moment M ref , then you need to solve the following equation:

[0068]

[0069] From the equation, we can see that F δ1 、F δ2 ,…,F δK 、M δ1 、M δ2 ,…,MδK is a known quantity, so the solution is δ i This equation is a multi-solution problem. There are two equations and K unknowns. At least two pairs of rudders are required to satisfy the equation. If there are more than two pairs of rudders, the calculation is performed according to the following strategy:

[0070] a) If K is an integer multiple of 2, group the surfaces into two pairs. For example, group the first and second pairs together, and the third and fourth pairs together. Evenly distribute the required direct force and pitching moment, and solve them using the average distribution formula.

[0071] b) If K is equal to (integer multiple of 2 + 1), remove one pair of control surfaces that meets the preset conditions. For example, the lift increment F of all pairs of control surfaces can be δi Sort by order from largest to smallest, removing the smallest F δi The pair of rudders (if there are more than two minimum F δi , randomly remove one pair). This pair of rudder surfaces is not used for pitch axis control allocation. The number of remaining rudder surfaces is exactly a multiple of 2, and can be calculated according to the method described in a);

[0072] The average distribution formula is:

[0073]

[0074] Where T represents the number of groups into which all pairs of rudder surfaces participating in the calculation are divided.

[0075] The deflection angle of each pair of rudder surfaces is solved by the average distribution formula. Then the deflection angle of each rudder surface can be assigned the same value according to the definition of the rudder surface. That is, for each pair of rudder surfaces, the deflection angles assigned to the two rudder surfaces are equal, both δ i .

[0076] Step 6: Output the deflection angle instructions of each rudder surface to the servo controller, so that the servo controller drives the rudder surface to deflect according to the deflection angle.

[0077] This application provides a method for suppressing vertical turbulence on a multi-control surface aircraft, enhancing the aircraft's ability to suppress vertical turbulence and improving flight quality. By simply adding a signal separation module, a turbulence suppression control algorithm, and a control surface allocation algorithm to the existing control law, vertical turbulence suppression can be achieved, demonstrating high engineering practical value.

[0078] Another embodiment of the present invention further provides a vertical turbulence suppression device for a multi-control surface aircraft, comprising:

[0079] Get modules for:

[0080] After the aircraft is in the altitude hold mode, the vertical velocity error signal is obtained.

[0081] Perform signal separation on the vertical velocity error signal to obtain a low-frequency signal and a high-frequency signal;

[0082] determining a pitch moment command based on the low-frequency signal;

[0083] Determine direct force command based on high frequency signal;

[0084] Generate the deflection angle command of each rudder surface according to the direct force command and the pitching moment command;

[0085] Output modules for:

[0086] The deflection angle instructions of each rudder surface are output to the servo controller, so that the servo controller drives the rudder surface to deflect.

[0087] Optionally, the aircraft has K pairs of control surfaces, K is greater than 2, and the acquisition module is specifically configured to:

[0088] When K is an integer multiple of 2, a deflection angle command for each rudder surface is generated according to a first calculation method. The first calculation method is as follows: K pairs of rudder surfaces are grouped, with two pairs of rudder surfaces forming one group, and the required direct force and pitching moment are evenly distributed to determine the deflection angle of each pair of rudder surfaces, so that the deflection angles of the two rudder surfaces in each pair are the same;

[0089] When K is equal to (an integer multiple of 2+1), a pair of rudder surfaces that meet the preset conditions is removed, and a deflection angle instruction for each rudder surface is generated according to the first calculation method.

[0090] The above merely describes the embodiments of the present application, which are described in a relatively specific and detailed manner, but should not be construed as limiting the scope of the invention. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the concept of the present application, and these modifications and improvements are all within the scope of protection of the present application.

Claims

1. A method for suppressing vertical turbulence of a multi-control surface aircraft, characterized in that: include: When the aircraft is in altitude hold mode, the vertical velocity error signal is obtained. Perform signal separation on the vertical velocity error signal to obtain a low-frequency signal and a high-frequency signal; determining a pitch moment command based on the low-frequency signal; Determine direct force command based on high frequency signal; Generate the deflection angle command of each rudder surface according to the direct force command and the pitching moment command; Outputting the deflection angle instructions of each rudder surface to the servo controller so that the servo controller drives the rudder surface to deflect; The aircraft has K pairs of control surfaces, K is greater than 2. Based on the direct force command and the pitch moment command, the deflection angle command of each control surface is generated, including: When K is an integer multiple of 2, a deflection angle command for each rudder surface is generated according to a first calculation method. The first calculation method is: K pairs of rudder surfaces are grouped, with two pairs of rudder surfaces as a group, and the direct force and pitching moment are evenly distributed to determine the deflection angle of each pair of rudder surfaces, so that the deflection angles of the two rudder surfaces in each pair are the same; When K is equal to an integer multiple of 2 plus 1, a pair of control surfaces that meet the preset conditions is removed, and a deflection angle instruction for each control surface is generated according to the first calculation method; The preset condition is: the lift increment generated by the pair of rudder surfaces deflecting 1 degree at the trim point smallest; The obtaining of the vertical velocity error signal comprises: According to the preset route altitude instruction received , altitude signal from the sensor system , vertical velocity signal from the sensor system , calculate the vertical velocity error signal , the calculation formula is: in, To control the gain.

2. The method according to claim 1, characterized in that The vertical velocity error signal is separated to obtain low-frequency and high-frequency signals, including: A low-pass filter is used to perform low-pass filtering on the vertical velocity error signal to obtain a low-frequency signal; The difference between the vertical velocity error signal and the low-frequency signal is used as the high-frequency signal.

3. The method according to claim 2, characterized in that The cutoff frequency of the low-pass filter is determined according to the pitch short-period cutoff frequency value in the aircraft body characteristics under maximum dynamic pressure.

4. The method according to claim 1, wherein Determine the pitch moment command based on the low-frequency signal, including: Generate a pitch angle command according to the low-frequency signal; According to the pitch angle command, the pitch moment command is determined by the pitch attitude control law.

5. The method according to claim 1, wherein Determine direct force commands based on high-frequency signals, including: According to the high-frequency signal, the proportional plus integral control channel is used to generate direct force instructions.

6. A vertical turbulence suppression device for a multi-control surface aircraft, characterized in that: The method for suppressing vertical turbulence of a multi-control surface aircraft according to any one of claims 1 to 5 is adopted, wherein the device comprises: Get modules for: After the aircraft is in the altitude hold mode, the vertical velocity error signal is obtained. Perform signal separation on the vertical velocity error signal to obtain a low-frequency signal and a high-frequency signal; determining a pitch moment command based on the low-frequency signal; Determine direct force command based on high frequency signal; Generate the deflection angle command of each rudder surface according to the direct force command and the pitching moment command; Output modules for: The deflection angle instructions of each rudder surface are output to the servo controller, so that the servo controller drives the rudder surface to deflect.

7. The device according to claim 6, characterized in that The aircraft has K pairs of control surfaces, K is greater than 2, and the acquisition module is specifically used to: When K is an integer multiple of 2, a deflection angle command for each rudder surface is generated according to a first calculation method. The first calculation method is: K pairs of rudder surfaces are grouped, with two pairs of rudder surfaces as one group, and the direct force and pitching moment are evenly distributed to determine the deflection angle of each pair of rudder surfaces, so that the deflection angles of the two rudder surfaces in each pair are the same; When K is equal to an integer multiple of 2 plus 1, a pair of control surfaces that meet the preset conditions are removed, and a deflection angle instruction for each control surface is generated according to the first calculation method.

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