Wheel type take-off and landing unmanned aerial vehicle brake control method and system

Abstract

The invention provides a wheel type take-off and landing unmanned aerial vehicle brake control method and system. The method comprises the steps that the taxiing lift force of an unmanned aerial vehicle is calculated; the pneumatic pitching moment of the unmanned aerial vehicle is calculated; based on the skating lift force, the pneumatic pitching moment, parameters of the unmanned aerial vehicle and a main wheel supporting force formula of the unmanned aerial vehicle, main wheel supporting force of the ground to main wheels of the unmanned aerial vehicle is obtained; obtaining the critical braking torque of the unmanned aerial vehicle based on the main wheel supporting force; and setting the brake instruction quantity of the unmanned aerial vehicle based on the critical brake torque, so that the brake instruction quantity of the unmanned aerial vehicle can be accurately set during takeoff and taxiing or landing and taxiing of the unmanned aerial vehicle, and the problems that the brake instruction quantity of an existing wheel type takeoff and landing unmanned aerial vehicle is inaccurate in control and cannot be accurately controlled are solved. Therefore, the problem that the braking distance is too long or the unmanned aerial vehicle swings laterally is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicles, and in particular to a braking control method and system for a wheeled take-off and landing unmanned aerial vehicle. Background Art

[0002] Unmanned aerial vehicle, referred to as "UAV", is an unmanned aircraft controlled by radio remote control equipment and self-contained program control device. It can be operated completely or intermittently autonomously by an onboard computer. UAVs can be divided into taxiing takeoff, rail takeoff, vertical takeoff, etc. according to the take-off method. Among them, wheeled take-off and landing UAVs mainly use taxiing to take off and land.

[0003] Wheeled take-off and landing UAVs usually need to brake and decelerate and correct the running direction during the take-off and / or landing roll. During the braking and deceleration process, the existing wheeled take-off and landing UAVs have the problem of inaccurate control of the braking command amount, which leads to excessively long braking distance or lateral swing of the UAV. Summary of the invention

[0004] The embodiments of the present application provide a braking control method and system for a wheeled take-off and landing UAV, which can solve the problem of inaccurate control of braking command quantity in existing wheeled take-off and landing UAVs, thereby resulting in excessively long braking distance or lateral swing of the UAV.

[0005] In a first aspect, an embodiment of the present application provides a brake control method for a wheeled take-off and landing UAV, comprising: Calculating the taxiing lift of the UAV; Calculating the aerodynamic pitch moment of the UAV; Obtaining the main wheel support force of the main wheel of the UAV from the ground based on the rolling lift, the aerodynamic pitch moment, the UAV's own parameters and the main wheel support force formula of the UAV; Obtaining a critical braking torque of the UAV based on the main wheel support force; A braking command amount of the drone is set based on the critical braking torque.

[0006] In some embodiments, the calculating the taxiing lift of the drone includes: Obtaining the indicated airspeed and rolling angle of attack of the UAV; Determining the lift coefficient of the UAV based on the rolling angle of attack and lift angle of attack table, wherein the lift coefficient of the UAV in the lift angle of attack table corresponds to the angle of attack;

[0007] Based on the indicated airspeed, the lift coefficient and the lift formula of the UAV Obtaining the taxiing lift of the UAV;

[0008] in, For taxiing lift, is the air density at sea level, is the indicated airspeed, is the lift coefficient.

[0009] In some embodiments, calculating the aerodynamic pitch moment of the drone includes:

[0010] Obtaining the indicated airspeed, rolling angle of attack and elevator angle of the UAV;

[0011] Determining a pitch moment coefficient of the UAV based on the rolling angle of attack, the elevator angle of deflection, and a force system lift table, wherein the pitch moment coefficient of the UAV in the force system lift table corresponds to the angle of attack and the elevator angle of deflection;

[0012] Based on the pitch moment coefficient, the indicated airspeed and the pitch moment formula of the UAV Obtaining the aerodynamic pitch moment of the UAV;

[0013] in, is the aerodynamic pitch moment, is the pitch moment coefficient, is the indicated airspeed, is the air density at sea level.

[0014] In some embodiments, the self parameters include the gravity, height, front wheel distance from the front wheel to the center of gravity of the drone, and rear wheel distance from the rear wheel to the center of gravity of the drone. The main wheel support force formula is: ;

[0015] in, The ground's support for the main wheels. is the height of the drone's center of gravity relative to the runway, For front wheel track, For rear wheelbase, is the front wheel rolling friction coefficient, is the main wheel sliding friction coefficient, The gravity of the drone, For taxiing lift, is the aerodynamic pitching moment.

[0016] In some embodiments, the critical braking torque of the drone is obtained based on the main wheel support force, specifically:

[0017] Based on the main wheel support force and critical braking torque formula Obtaining a critical braking torque of the UAV;

[0018] in, is the critical braking torque, The ground's support for the main wheels. is the main wheel sliding friction coefficient, The radius of the main wheel.

[0019] In some embodiments, setting the braking instruction amount of the drone based on the critical braking torque includes: Determining a critical braking command amount of the drone based on the critical braking torque; The braking command amount is determined based on the critical braking command amount and a safety factor.

[0020] In some embodiments, the step of setting the braking instruction amount of the drone based on the critical braking torque further includes: Collecting multiple yaw angles of the UAV within a preset time period; Obtaining a yaw angle extreme difference within the preset time period based on the multiple yaw angles; If the yaw angle extreme difference is greater than the extreme difference threshold, the braking instruction amount is reduced.

[0021] In some embodiments, the collecting of multiple yaw angles of the drone within a preset time period includes: Set the collection interval for collecting yaw angles. Determining the collection quantity based on the preset time period and the collection interval; A plurality of yaw angles of the UAV are collected based on the collection interval and the collection quantity.

[0022] In a second aspect, an embodiment of the present application provides a brake control system for a wheeled take-off and landing UAV, comprising: The main wheel calculation module is used to calculate the taxiing lift of the UAV; calculate the aerodynamic pitch moment of the UAV; and obtain the main wheel support force of the ground on the main wheel of the UAV based on the taxiing lift, the aerodynamic pitch moment, the UAV's own parameters and the main wheel support force formula of the UAV; A critical moment module, used to obtain a critical braking moment of the UAV based on the main wheel support force; A braking command module is used to set a braking command amount of the drone based on the critical braking torque.

[0023] In a third aspect, an embodiment of the present application provides an electronic device, including a wheeled take-off and landing UAV brake control system as described in the second aspect.

[0024] Compared with the prior art, the advantages of the embodiments of the present application are that, by calculating the taxiing lift of the UAV; calculating the aerodynamic pitch moment of the UAV; obtaining the main wheel support force of the ground on the main wheel of the UAV based on the taxiing lift, the aerodynamic pitch moment, the UAV's own parameters and the main wheel support force formula of the UAV; obtaining the critical braking torque of the UAV based on the main wheel support force; and setting the braking command amount of the UAV based on the critical braking torque, the braking command amount of the UAV can be accurately set during the take-off roll or landing roll of the UAV, thereby solving the problem of inaccurate control of the braking command amount of existing wheeled take-off and landing UAVs, which leads to excessively long braking distance or lateral swing of the UAV. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Hereinafter, the present invention will be described in more detail based on embodiments and with reference to the accompanying drawings.

[0026] Figure 1 is a flow chart of a brake control method for a wheeled take-off and landing UAV provided by an embodiment of the present invention; Figure 2 This is a force diagram of the main wheel locked state of a UAV during unpowered taxiing provided by an embodiment of the present invention; Figure 3 This is a force diagram of the main wheel of a drone provided by an embodiment of the present invention; Figure 4 It is a schematic diagram of a brake control system for a wheeled take-off and landing UAV provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings.

[0028] UAV is a general term for unmanned aerial vehicles, which are unmanned aerial vehicles controlled by radio remote control equipment and self-contained program control devices. Based on the platform configuration, they are divided into fixed-wing UAVs, rotary-wing UAVs, unmanned airships, paraglider UAVs, flapping-wing UAVs, etc. Compared with manned aircraft, UAVs have the advantages of low environmental requirements and low manufacturing and use costs.

[0029] According to the launch and recovery method, wheeled take-off and landing drones are a large category of drones. This type of drone uses wheeled taxiing to complete launch (take-off) and recovery (landing). The take-off taxiing starts when the drone receives the take-off command. The engine throttle quickly increases from the idle throttle to the take-off throttle, and the drone accelerates and taxis. When the speed reaches the lift-off speed, the elevator is deflected, and the drone leaves the ground and completes the take-off process. During the take-off process, if there is a situation such as a failure of the onboard equipment that does not allow continued take-off, and the drone speed is less than the take-off decision speed, the take-off needs to be interrupted. At this time, the engine needs to be shut down immediately, and the brakes need to be applied to slow down until the drone stops; the landing taxiing starts when the drone wheels touch the ground, and then the drone performs a landing taxiing with the engine turned off or idling, and gradually slows down through the main wheel brakes until it stops.

[0030] Most wheeled take-off and landing UAVs use a three-point front landing gear configuration, that is, a front wheel is installed at the front end of the UAV, and a main wheel is installed on the left and right sides of the rear end. Wheeled take-off and landing UAVs generally have braking devices, steering devices, rudders, etc. Among them, the braking device is installed on the main wheel, and it receives the braking command from the flight control computer to brake the main wheel to slow down the UAV; the steering device is installed on the front landing gear, and it receives the command from the flight control computer to drive the front wheel to change direction to turn the UAV. Generally, the front wheel steering and the rudder work together to complete the steering of the UAV's taxiing, thereby achieving lateral correction of the UAV's taxiing.

[0031] During the UAV's interrupted takeoff and landing rolls, in addition to braking and deceleration, the front wheel steering device and rudder deflection are also used to correct the runway, so that the UAV can decelerate and roll along the runway. In this process, if the braking amount is too small, the braking and deceleration distance will be too long, and there will be a risk that the UAV will run out of the end of the runway; if the braking amount is too large, the lateral ground adhesion coefficient of the UAV's wheels will drop significantly, and the stability of the runway correction will be reduced, and the nose will easily swing left and right, and the trajectory will "draw a dragon" or even "flick the tail", which seriously threatens the safety of the runway. Therefore, during the UAV's interrupted takeoff and landing rolls, the deceleration brake needs to be effectively controlled or adjusted to reduce the runway distance as much as possible while ensuring the safety of the runway.

[0032] If the UAV's braking device has an anti-skid (ABS, anti-lock braking system) function, a larger braking command can be given to the braking device, and the ABS (anti-lock braking system) ensures that the wheels have an optimal slip rate, and can simultaneously ensure high braking efficiency and sufficient lateral adhesion coefficient, so that the UAV can taxi stably and the taxiing distance is short. However, for existing small and medium-sized UAVs, in order to save costs, the braking devices generally do not have an anti-skid function. During the braking and deceleration process, the existing wheeled take-off and landing UAVs have the problem of inaccurate control of the braking command amount, which leads to excessively long braking distance or lateral swing of the UAV.

[0033] First, as Figure 1 , Figure 2 As shown, in order to solve the above technical problems, the embodiment of the present application provides a brake control method for a wheeled take-off and landing UAV, comprising: S101: Calculating the taxiing lift of the UAV; In some embodiments, the calculating the taxiing lift of the drone includes: Obtaining the indicated airspeed and rolling angle of attack of the UAV; Determining the lift coefficient of the UAV based on the rolling angle of attack and lift angle of attack table, wherein the lift coefficient of the UAV in the lift angle of attack table corresponds to the angle of attack; Based on the indicated airspeed, the lift coefficient and the lift formula of the UAV Obtaining the taxiing lift of the UAV;

[0034] in, For taxiing lift, is the air density at sea level, is the indicated airspeed, is the lift coefficient.

[0035] It should be noted that the indicated airspeed It refers to the speed of the aircraft relative to the air at the altitude converted to the speed at sea level, and the converted speed has the same dynamic pressure. It can be measured and output by the airborne equipment atmospheric machine. It refers to the angle between the projection of the aircraft's airspeed vector on the aircraft's symmetry plane and the longitudinal axis of the aircraft. During flight, the aerodynamic force acting on the aircraft is related to the angle of attack. Within a certain range of angles of attack, increasing the angle of attack will increase the lift coefficient. Increase.

[0036] It should be noted that the lift coefficient It refers to the ratio of the lift force on the aircraft to the product of the aircraft dynamic pressure and the reference area, and the lift coefficient Usually related to the angle of attack, so the lift coefficient can be constructed in advance ( ) and the angle of attack of the drone The corresponding lift system angle of attack table is , in determining the lift coefficient of the UAV When Perform one-dimensional linear interpolation to obtain , so the lift coefficient of the UAV can be determined , wherein the rolling angle of attack Can be measured by sensors (since the runway is approximately horizontal, the roll-out angle of attack Approximately equal to the pitch angle of the drone), this application does not make specific limitations on this.

[0037] S102: Calculating the aerodynamic pitch moment of the UAV;

[0038] In some embodiments, calculating the aerodynamic pitch moment of the drone includes:

[0039] Obtaining the indicated airspeed, rolling angle of attack and elevator angle of the UAV;

[0040] Determining a pitch moment coefficient of the UAV based on the rolling angle of attack, the elevator angle of deflection, and a force system lift table, wherein the pitch moment coefficient of the UAV in the force system lift table corresponds to the angle of attack and the elevator angle of deflection;

[0041] Based on the pitch moment coefficient, the indicated airspeed and the pitch moment formula of the UAV Obtaining the aerodynamic pitch moment of the UAV;

[0042] in, is the aerodynamic pitch moment, is the pitch moment coefficient, is the indicated airspeed, is the air density at sea level.

[0043] It should be noted that the aerodynamic pitch moment It refers to the moment around the z-axis of the aircraft body generated by the aerodynamic force acting on the aircraft (such as Figure 2 As shown in the figure, the elevator is the "rudder" that controls the pitch of the aircraft. When the aircraft needs to be manipulated to raise or lower its head (pitch manipulation is performed during taxiing to make the pitch angle of the drone change according to the set rules), the elevator in the horizontal tail will come into play. The elevator is the controllable wing surface part of the horizontal tail, and its function is to perform pitch manipulation on the aircraft. The elevator deflection angle is the angle of elevator deflection, the elevator deflection angle and the rolling angle of attack Together they affect the pitch moment coefficient , so the pitch moment coefficient can be constructed in advance ( ) and elevator deflection angle 、UAV angle of attack The corresponding two-dimensional table, that is, the force system deflection table , in determining the pitching moment coefficient When the force system deflection table Perform two-dimensional linear interpolation to obtain , so the pitch moment coefficient of the UAV can be determined .

[0044] S103: Obtaining a main wheel support force of the ground on the main wheel of the UAV based on the rolling lift, the aerodynamic pitch moment, the UAV's own parameters and the main wheel support force formula of the UAV;

[0045] In some embodiments, the self parameters include the gravity, height, front wheel distance from the front wheel to the center of gravity of the drone, and rear wheel distance from the rear wheel to the center of gravity of the drone. The main wheel support force formula is: ;

[0046] in, The ground's support for the main wheels. is the height of the drone's center of gravity relative to the runway, For front wheel track, For rear wheelbase, is the front wheel rolling friction coefficient, is the main wheel sliding friction coefficient, The gravity of the drone, For taxiing lift, is the aerodynamic pitching moment.

[0047] It should be noted that if Figure 2 As shown, the take-off and / or landing roll of the UAV can be subjected to force analysis in advance. Since the pitch angle (i.e., the roll angle of the UAV) when rolling on the runway is ) is generally small (usually a few degrees), so the longitudinal axis of the drone is approximately considered to be parallel to the runway, and the center of gravity height of the drone relative to the runway is , the longitudinal distance between the front wheel and the center of gravity of the drone is , the longitudinal distance between the main wheel axle and the center of gravity of the UAV is The external forces and moments on the UAV in the longitudinal direction include the support force of the runway (i.e. the ground) on the front wheels: , the front wheel rolling friction is The total support force of the runway on the two main wheels is The combined braking force of the two main wheels is , gravity is , the taxiing lift is , the aerodynamic pitch moment is (Each force is positive when it is upward, and the pitch moment that makes the drone look up is positive), thus the force balance formula of the drone in the vertical direction can be constructed , and the center of gravity moment balance formula of the drone in, , , according to the force balance formula And the center of gravity moment balance formula The main wheel support force formula can be obtained .

[0048] It should be noted that, in obtaining the rolling lift and the aerodynamic pitch moment Then, the rolling lift and the aerodynamic pitch moment Substitute into the main wheel support force formula The main wheel support force of the runway (or ground) on the main wheel can be obtained .

[0049] S104: Obtaining a critical braking torque of the UAV based on the main wheel support force;

[0050] In some embodiments, the critical braking torque of the drone is obtained based on the main wheel support force, specifically:

[0051] Based on the main wheel support force and critical braking torque formula Obtaining a critical braking torque of the UAV;

[0052] in, is the critical braking torque, The ground's support for the main wheels. is the main wheel sliding friction coefficient, The radius of the main wheel.

[0053] It should be noted that if Figure 3 As shown, the stress state of the main wheel can be analyzed in advance. The main wheel axis, is the main wheel radius, is the cooperative force of the axle on the main wheel, is the support force of the runway on the main wheels, The braking force of the main wheel, is the braking torque of the brake device on the main wheel, ignoring the rotational inertia of the main wheel to the axle, so the main wheel to the axle torque is balanced, and the main wheel torque balance formula is obtained If the main wheel enters the sliding state, , , so the critical braking torque formula can be obtained , and the critical braking torque .

[0054] S105: Setting a braking command amount of the drone based on the critical braking torque.

[0055] In some embodiments, setting the braking instruction amount of the drone based on the critical braking torque includes:

[0056] Determining a critical braking command amount of the drone based on the critical braking torque;

[0057] The braking command amount is determined based on the critical braking command amount and a safety factor.

[0058] It should be noted that the braking torque of the brake device on the main wheel Braking command (i.e. the braking command sent by the flight control computer to the braking device) has a certain corresponding relationship, i.e. the braking torque Corresponding brake command amount , from which the braking torque can be constructed Braking command The corresponding table, that is, the brake gauge , after obtaining the critical braking torque After that, you can use the brake gauge Perform one-dimensional linear interpolation to obtain the corresponding critical braking command amount ,Right now , that is, the braking command amount is When the main wheel braking torque is , at this time the main wheel just locked.

[0059] It should be noted that due to the errors in the aerodynamic layout, structural dimensions, rolling friction coefficient, sliding friction coefficient, etc. of the UAV, in order to avoid the main wheel locking, which will cause the main wheel lateral adhesion coefficient to drop seriously and cause lateral instability during taxiing, the braking command given by the flight control computer to the braking device usually needs to consider a safety factor. The flight control computer gives the brake device a braking command of ,in, is the brake command amount, Generally, it is taken as 0.7~0.9.

[0060] In some embodiments, the step of setting the braking instruction amount of the drone based on the critical braking torque further includes:

[0061] Collecting multiple yaw angles of the UAV within a preset time period;

[0062] Obtaining a yaw angle extreme difference within the preset time period based on the multiple yaw angles;

[0063] If the yaw angle extreme difference is greater than the extreme difference threshold, the braking instruction amount is reduced.

[0064] In some embodiments, the collecting of multiple yaw angles of the drone within a preset time period includes:

[0065] Set the collection interval for collecting yaw angles.

[0066] Determining the collection quantity based on the preset time period and the collection interval;

[0067] A plurality of yaw angles of the UAV are collected based on the collection interval and the collection quantity.

[0068] It should be noted that in order to further ensure the stability of the UAV's taxiing, the yaw angle of the UAV relative to the runway can be periodically monitored during the braking and deceleration taxiing so as to make timely adjustments. The yaw angle range is the maximum value among the multiple yaw angles. With minimum value If the difference , it means that the UAV is not rolling stably, and the braking command amount needs to be reduced. ,in, is the extreme difference threshold, The value range is [0.5,3] (unit: °), and the general value is 1.5.

[0069] It should be noted that the preset time period The range is [0.5,2] (unit: s), =1, the collection interval The range is [0.02, 0.2] (unit: s), usually =0.1, the preset time period and the acquisition interval The specific value of can be adjusted according to actual needs, wherein, when determining the number of collections To ensure the number of For integers, the function Determine the number of acquisitions .

[0070] It should be noted that when reducing the braking command amount You can proceed as follows:

[0071] 1) Get the current time , brake command amount ;

[0072] 2) From Start, every collection interval Collect the yaw angle once, arrive During the time interval, a total of Secondary yaw angle (round(x) means taking the integer part of x);

[0073] 3) Find the maximum value among N yaw angles and minimum value ;

[0074] 4) If , then n=n+1, the braking command amount ,make , go to step 2); otherwise, go to step 1).

[0075] in, It is the instruction reduction amplitude, the value range is [1,5] (unit %), and the general value is 3%.

[0076] To sum up, compared with the prior art, the advantages of the embodiments of the present application are that, by calculating the taxiing lift of the UAV; calculating the aerodynamic pitch moment of the UAV; obtaining the main wheel support force of the ground on the main wheel of the UAV based on the taxiing lift, the aerodynamic pitch moment, the UAV's own parameters and the main wheel support force formula of the UAV; obtaining the critical braking torque of the UAV based on the main wheel support force; setting the braking command amount of the UAV based on the critical braking torque, the braking command amount of the UAV can be accurately set during the take-off taxiing or landing taxiing of the UAV, thereby solving the problem of inaccurate control of the braking command amount of the existing wheeled take-off and landing UAVs, which leads to excessive braking distance or lateral swing of the UAV.

[0077] Second, as Figure 4 As shown, the embodiment of the present application provides a brake control system for a wheeled take-off and landing UAV, comprising:

[0078] The main wheel calculation module 410 is used to calculate the taxiing lift of the UAV; calculate the aerodynamic pitch moment of the UAV; and obtain the main wheel support force of the ground on the main wheel of the UAV based on the taxiing lift, the aerodynamic pitch moment, the UAV's own parameters and the main wheel support force formula of the UAV;

[0079] A critical moment module 420, configured to obtain a critical braking moment of the UAV based on the main wheel support force;

[0080] The braking command module 430 is used to set the braking command amount of the drone based on the critical braking torque.

[0081] In some embodiments, the calculating the taxiing lift of the drone includes:

[0082] Obtaining the indicated airspeed and rolling angle of attack of the UAV;

[0083] Determining the lift coefficient of the UAV based on the rolling angle of attack and lift angle of attack table, wherein the lift coefficient of the UAV in the lift angle of attack table corresponds to the angle of attack;

[0084] Based on the indicated airspeed, the lift coefficient and the lift formula of the UAV Obtaining the taxiing lift of the UAV;

[0085] in, For taxiing lift, is the air density at sea level, is the indicated airspeed, is the lift coefficient.

[0086] In some embodiments, calculating the aerodynamic pitch moment of the drone includes:

[0087] Obtaining the indicated airspeed, rolling angle of attack and elevator angle of the UAV;

[0088] Determining a pitch moment coefficient of the UAV based on the rolling angle of attack, the elevator angle of deflection, and a force system lift table, wherein the pitch moment coefficient of the UAV in the force system lift table corresponds to the angle of attack and the elevator angle of deflection;

[0089] Based on the pitch moment coefficient, the indicated airspeed and the pitch moment formula of the UAV Obtaining the aerodynamic pitch moment of the UAV;

[0090] in, is the aerodynamic pitch moment, is the pitch moment coefficient, is the indicated airspeed, is the air density at sea level.

[0091] In some embodiments, the self parameters include the gravity, height, front wheel distance from the front wheel to the center of gravity of the drone, and rear wheel distance from the rear wheel to the center of gravity of the drone. The main wheel support force formula is: ;

[0092] in, The ground's support for the main wheels. is the height of the drone's center of gravity relative to the runway, For front wheel track, For rear wheelbase, is the front wheel rolling friction coefficient, is the main wheel sliding friction coefficient, The gravity of the drone, For taxiing lift, is the aerodynamic pitching moment.

[0093] In some embodiments, the critical braking torque of the drone is obtained based on the main wheel support force, specifically:

[0094] Based on the main wheel support force and critical braking torque formula Obtaining a critical braking torque of the UAV;

[0095] in, is the critical braking torque, The ground's support for the main wheels. is the main wheel sliding friction coefficient, The radius of the main wheel.

[0096] In some embodiments, setting the braking instruction amount of the drone based on the critical braking torque includes: Determining a critical braking command amount of the drone based on the critical braking torque; The braking command amount is determined based on the critical braking command amount and a safety factor.

[0097] In some embodiments, the step of setting the braking instruction amount of the drone based on the critical braking torque further includes: Collecting multiple yaw angles of the UAV within a preset time period; Obtaining a yaw angle extreme difference within the preset time period based on the multiple yaw angles; If the yaw angle extreme difference is greater than the extreme difference threshold, the braking instruction amount is reduced.

[0098] In some embodiments, the collecting of multiple yaw angles of the drone within a preset time period includes: Set the collection interval for collecting yaw angles. Determining the collection quantity based on the preset time period and the collection interval; A plurality of yaw angles of the UAV are collected based on the collection interval and the collection quantity.

[0099] In a third aspect, an embodiment of the present application provides an electronic device, including a wheeled take-off and landing UAV brake control system as described in any one of the second aspects.

[0100] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and / or computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0101] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0102] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0103] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A brake control method for a wheeled take-off and landing UAV, characterized in that: include: Calculating the taxiing lift of the UAV; Calculating the aerodynamic pitch moment of the UAV; Obtaining the main wheel support force of the main wheel of the UAV from the ground based on the rolling lift, the aerodynamic pitch moment, the UAV's own parameters and the main wheel support force formula of the UAV; Obtaining a critical braking torque of the UAV based on the main wheel support force; A braking command amount of the drone is set based on the critical braking torque.

2. The wheeled take-off and landing UAV brake control method according to claim 1, characterized in that: The calculating the taxiing lift of the UAV comprises: Obtaining the indicated airspeed and rolling angle of attack of the UAV; Determining the lift coefficient of the UAV based on the rolling angle of attack and lift angle of attack table, wherein the lift coefficient of the UAV in the lift angle of attack table corresponds to the angle of attack; Based on the indicated airspeed, the lift coefficient and the lift formula of the UAV Obtaining the taxiing lift of the UAV; in, For taxiing lift, is the air density at sea level, is the indicated airspeed, is the lift coefficient.

3. The wheeled take-off and landing UAV brake control method according to claim 1, characterized in that: The calculating the aerodynamic pitch moment of the UAV comprises: Obtaining the indicated airspeed, rolling angle of attack, and elevator angle of the UAV; Determining a pitch moment coefficient of the UAV based on the rolling angle of attack, the elevator angle of deflection, and a force system lift table, wherein the pitch moment coefficient of the UAV in the force system lift table corresponds to the angle of attack and the elevator angle of deflection; Based on the pitch moment coefficient, the indicated airspeed and the pitch moment formula of the UAV Obtaining the aerodynamic pitch moment of the UAV; in, is the aerodynamic pitch moment, is the pitch moment coefficient, is the indicated airspeed, is the air density at sea level.

4. The wheeled take-off and landing UAV brake control method according to claim 1, characterized in that: The self parameters include the gravity, height, front wheel distance from the front wheel to the center of gravity of the drone, and rear wheel distance from the rear wheel to the center of gravity of the drone. The main wheel support force formula is: ; in, The ground's support for the main wheels. is the center of gravity height of the drone, For front wheel track, For rear wheelbase, is the front wheel rolling friction coefficient, is the main wheel sliding friction coefficient, The gravity of the drone, For taxiing lift, is the aerodynamic pitching moment.

5. The brake control method for a wheeled take-off and landing UAV according to claim 1, characterized in that: The critical braking torque of the UAV obtained based on the main wheel support force is specifically: Based on the main wheel support force and critical braking torque formula Obtaining a critical braking torque of the UAV; in, is the critical braking torque, The ground's support for the main wheels. is the main wheel sliding friction coefficient, The radius of the main wheel.

6. The wheeled take-off and landing UAV brake control method according to claim 1, characterized in that: The step of setting the braking instruction amount of the drone based on the critical braking torque includes: Determining a critical braking command amount of the drone based on the critical braking torque; The braking command amount is determined based on the critical braking command amount and a safety factor.

7. The brake control method for a wheeled take-off and landing UAV according to claim 1, characterized in that: The step of setting the braking instruction amount of the drone based on the critical braking torque further includes: Collecting multiple yaw angles of the UAV within a preset time period; Obtaining a yaw angle extreme difference within the preset time period based on the multiple yaw angles; If the yaw angle extreme difference is greater than the extreme difference threshold, the braking instruction amount is reduced.

8. The wheeled take-off and landing UAV brake control method according to claim 7, characterized in that: The collecting of multiple yaw angles of the drone within a preset time period includes: Set the collection interval for collecting yaw angles. Determining the collection quantity based on the preset time period and the collection interval; A plurality of yaw angles of the UAV are collected based on the collection interval and the collection quantity.

9. A wheeled take-off and landing UAV brake control system, characterized in that: include: A main wheel calculation module, used to calculate the taxiing lift of the UAV; Calculating the aerodynamic pitch moment of the UAV; Obtaining the main wheel support force of the main wheel of the UAV from the ground based on the rolling lift, the aerodynamic pitch moment, the UAV's own parameters and the main wheel support force formula of the UAV; A critical moment module, used to obtain a critical braking moment of the UAV based on the main wheel support force; A braking command module is used to set a braking command amount of the drone based on the critical braking torque.

10. An electronic device, characterized in that: It includes a wheeled take-off and landing UAV brake control system as described in claim 9.

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