A Closed-Loop Control Method, Device and System for Variable-Pitch Propellers of Unmanned Aerial Vehicles

Abstract

The present invention relates to the field of unmanned aerial vehicle (UAV) equipment, and discloses a closed-loop control method, device and system for a variable pitch propeller of a UAV. The closed-loop control system includes a flight controller, a servo, a variable pitch control structure and a wire displacement sensor; one end of the wire displacement sensor is connected to the output point of the variable pitch control structure through a sensor wire, and the other end is electrically connected to the flight controller; the flight controller is electrically connected to the servo; the servo is connected to the input point of the variable pitch control structure through a servo arm / push rod; the variable pitch control structure is also connected to the UAV propeller, and the displacement change between the input point and the output point of the variable pitch control structure drives the change of the blade angle of the UAV propeller. The closed-loop control system composed of the invention can effectively compensate for the control deviation of the open-loop control system, accurately output the blade angle that can exert the maximum effective power of the engine / motor, improve energy efficiency, and also play a role in system fault monitoring.

Description

Technical Field

[0001] The present invention relates to the field of unmanned aerial vehicle (UAV) equipment, and particularly to a closed-loop control method, device and system for a variable-pitch propeller of a UAV. Background Art

[0002] The variable pitch of a UAV propeller refers to the control process in which, during the flight of a UAV, in order to enable the engine / motor to exert the maximum effective power, the propeller automatically (or manually) changes the blade angle according to the flight speed. The corresponding relationship between the propeller blade angle and the flight speed can generally be provided by the engine / motor manufacturer or obtained by fitting the test data of the engine / motor test bench. This control process generally controls the servo by the flight controller, and the servo drives the variable pitch control structure to achieve. In the actual flight process at present, the flight controller calculates the expected blade angle of the propeller when the engine / motor exerts the maximum effective power according to the flight speed, and then gives the corresponding servo control amount according to this expected blade angle (the blade angle and the servo control amount are generally linearly related and obtained through static calibration of the ground rudder). The servo drives the variable pitch control structure output point to move a certain stroke amount according to the control amount to achieve the variable pitch of the propeller. The entire control process is an open-loop control based on prior data under static conditions without feedback calibration.

[0003] The existing variable pitch control of a UAV propeller is an open-loop control. In the actual flight process, due to mechanical errors such as the installation slack of the actuator and the deformation of the variable pitch control structure under dynamic load conditions, there will be a deviation between the actual blade angle of the propeller and the expected blade angle of the flight controller. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a closed-loop control method for a variable-pitch propeller of a UAV, including: receiving the moving displacement of the output point of the variable pitch control structure collected by a wire displacement sensor; calculating the servo control amount according to the expected blade angle and the moving displacement of the output point of the variable pitch control structure fed back by the wire displacement sensor; and transmitting the servo output amount to the servo.

[0005] Further, the expected blade angle is calculated according to the linear conversion relationship between the propeller blade angle and the flight speed provided by the manufacturer or pre-tested and fitted, and combined with the current flight speed of the UAV, to calculate the corresponding blade angle size when the engine / motor exerts the maximum effective power.

[0006] Further, calculating the servo control amount specifically includes the following sub-steps: calculating the actual propeller blade angle according to the moving displacement of the output point of the variable pitch control structure fed back by the wire displacement sensor, and calculating the feedforward of the servo control amount according to the expected blade angle; calculating the deviation value between the actual blade angle and the expected blade angle; calculating the compensation of the servo control amount according to the deviation between the actual blade angle and the expected blade angle; and adding the feedforward of the servo control amount and the compensation of the servo control amount to obtain the output of the flight controller servo control amount.

[0007] The present invention also discloses a flight controller for an unmanned aerial vehicle, which includes a receiving unit, a servo control quantity calculation unit, and a transmitting unit; the receiving unit receives the moving displacement quantity of the output point of the pitch-changing control structure collected by the wire displacement sensor; the servo control quantity calculation unit calculates the servo control quantity according to the desired blade angle and the moving displacement quantity of the output point of the pitch-changing control structure fed back by the wire displacement sensor; the transmitting unit transmits the servo output quantity to the servo.

[0008] Furthermore, the servo control quantity calculation unit specifically includes an actual propeller blade angle calculation module, a servo control quantity feedforward calculation module, a blade angle deviation value calculation module, a servo control quantity compensation calculation module, and a flight controller servo control quantity calculation module;

[0009] The actual propeller blade angle calculation module calculates the actual propeller blade angle according to the moving displacement quantity of the output point of the pitch-changing control structure fed back by the wire displacement sensor; the servo control quantity feedforward calculation module calculates the servo control quantity feedforward according to the desired blade angle; the blade angle deviation value calculation module is used to calculate the deviation value between the actual blade angle and the desired blade angle; the servo control quantity compensation calculation module calculates the servo control quantity compensation according to the deviation between the actual blade angle and the desired blade angle; the flight controller servo control quantity calculation module adds the servo control quantity feedforward and the servo control quantity compensation to obtain the flight controller servo control quantity.

[0010] Furthermore, the flight controller for the unmanned aerial vehicle further includes an ADC module for converting the analog signal of the moving displacement quantity of the output point of the pitch-changing control structure collected by the wire displacement sensor into a digital signal.

[0011] Furthermore, the flight controller for the unmanned aerial vehicle further includes a PWM module for converting the calculated flight controller servo control quantity into a PWM control signal and transmitting the PWM control signal to the servo.

[0012] The present invention also discloses a closed-loop control system for an unmanned aerial vehicle variable pitch propeller, including: the flight controller for the unmanned aerial vehicle according to any one of the above, a servo, a pitch-changing control structure, and a wire displacement sensor;

[0013] One end of the wire displacement sensor is connected to the output point of the pitch-changing control structure through a sensor wire, and the other end is electrically connected to the flight controller; the flight controller is electrically connected to the servo; the servo is connected to the input point of the pitch-changing control structure through a servo arm / push rod; the pitch-changing control structure is also connected to the unmanned aerial vehicle propeller, and the displacement change between the input point and the output point of the pitch-changing control structure drives the change of the blade angle of the unmanned aerial vehicle propeller.

[0014] The present invention also discloses a control method for a closed-loop control system of an unmanned aerial vehicle variable pitch propeller, which is applied to the closed-loop control system of the unmanned aerial vehicle variable pitch propeller, and includes:

[0015] The wire-pulling displacement sensor collects the moving displacement of the output point of the pitch-changing control structure and feeds back the moving displacement of the output point of the pitch-changing control structure to the flight control;

[0016] The flight control calculates the servo control amount based on the desired blade angle and the moving displacement of the output point of the pitch-changing control structure fed back by the wire-pulling displacement sensor, and transmits the servo output amount to the servo;

[0017] The servo drives the input point of the pitch-changing control structure to move a corresponding displacement according to the servo control amount;

[0018] The pitch-changing control structure transmits the force and moving displacement of the input point to the output point through the internal structure, changes the moving displacement of the output point, and thus changes the size of the propeller blade angle.

[0019] The present invention also discloses a computer storage medium, which is characterized by including: at least one memory and at least one processor;

[0020] The memory is used to store one or more program instructions;

[0021] The processor is used to run one or more program instructions to execute a closed-loop control method for an unmanned aerial vehicle variable pitch propeller described in any one of the above.

[0022] The beneficial effects of the present invention are:

[0023] (1) The invention consists of a flight control, a servo, a pitch-changing control structure and a wire-pulling displacement sensor to form a closed-loop control system. The wire-pulling displacement sensor measures the displacement change of the output point of the pitch-changing control structure, transmits it to the flight control, and the flight control transmits it to the servo. The servo drives the input point of the pitch-changing control structure to rotate through the servo arm or push rod, and the input point motion is transmitted to the output point. Thus, there are both signal inputs and signal feedbacks in the control system, realizing the closed-loop control of the unmanned aerial vehicle system.

[0024] (2) The closed-loop control system for the variable pitch propeller of the unmanned aerial vehicle of the present invention can not only effectively compensate the control deviation of the open-loop control system, accurately output the blade angle that can exert the maximum effective power of the engine / motor, improve energy efficiency, but also play a role in system fault monitoring. Description of the Drawings

[0025] Figure 1 It is a schematic diagram of a closed-loop control system for a variable pitch propeller of an unmanned aerial vehicle provided in Embodiment 1 of the present invention;

[0026] Figure 2 and Figure 3 It is a schematic diagram of the pitch-changing control structure of the present invention;

[0027] Figure 4 It is a flowchart of a closed-loop control method for a variable pitch propeller of an unmanned aerial vehicle provided in Embodiment 2 of the present invention;

[0028] Figure 5 It is a specific operation flowchart for calculating the control amount of the steering gear;

[0029] Figure 6 It is a schematic diagram of a variable pitch propeller closed-loop control device for an unmanned aerial vehicle provided in Embodiment 3 of the present invention;

[0030] Figure 7 It is a flowchart of a variable pitch propeller closed-loop control method for an unmanned aerial vehicle provided in Embodiment 4 of the present invention.

[0031] In the figure: 1, flight control; 2, steering gear; 3, variable pitch control structure; 4, wire displacement sensor; 5, unmanned aerial vehicle propeller; 6, power connector; 31, torque input point structure; 32, torque transmission structure; 33, torque output point structure; 311, joystick; 312, input end block; 61, receiving unit; 62, steering gear control amount calculation unit; 63, sending unit; 621, actual propeller blade angle calculation module; 622, steering gear control amount feedforward calculation module; 623, blade angle deviation value calculation module; 624, steering gear control amount compensation calculation module; 625, flight control steering gear control amount calculation module. Specific embodiments

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] Embodiment 1

[0034] Refer to Figures 1-3 : Embodiment 1 of the present invention provides a variable pitch propeller closed-loop control system for an unmanned aerial vehicle, including a flight control 1, a steering gear 2, a variable pitch control structure 3, and a wire displacement sensor 4; the flight control 1 is connected to the steering gear 2, the steering gear 2 is connected to the variable pitch control structure 3, the variable pitch control structure 3 is connected to the wire displacement sensor 4, and the wire displacement sensor 4 is connected to the flight control 1 again, thus forming a closed-loop control system.

[0035] Among them, one end of the wire displacement sensor 4 is connected to the output point of the variable pitch control structure 3 through a sensor wire, and the other end is electrically connected to the flight control 1; the flight control 1 is electrically connected to the steering gear 2; the steering gear 2 is connected to the input point of the variable pitch control structure 3 through a steering gear arm / push rod; the variable pitch control structure 3 is also connected to the unmanned aerial vehicle propeller 5, and the displacement change between the input point and the output point of the variable pitch control structure 3 drives the change of the blade angle of the unmanned aerial vehicle propeller 5.

[0036] Specifically, one end of the wire-pulling displacement sensor 4 is connected to the output point of the pitch-changing control structure 3 to measure the displacement of the output point of the pitch-changing control structure 3, and the other end is electrically connected to the flight control 1 through the first signal line S and the first signal ground wire G. An ADC module is provided between the wire-pulling displacement sensor 4 and the flight control 1 to convert the analog signal of the displacement of the output point of the wire-pulling displacement sensor 4 into a digital signal of the flight control and transmit it to the flight control 1.

[0037] The flight control 1 is electrically connected to the servo 2 through the second signal line S and the second signal ground wire G. A PWM module is provided between the flight control 1 and the servo 2 to convert the signal of the flight control 1 into a PWM control signal of the servo and transmit it to the servo 2;

[0038] The servo 2 is connected to the input point of the pitch-changing control structure 3 through a servo arm / push rod, and drives the input point of the pitch-changing control structure 3 to move the displacement through the servo arm / push rod. The pitch-changing control structure 3 transmits the displacement of the input point to the output point to change the displacement of the output point; the pitch-changing control structure 3 is also connected to the drone propeller 5, and the displacement changes of the input point and the output point of the pitch-changing control structure realize the blade angle change of the drone propeller 5.

[0039] The servo 2 and the wire-pulling displacement sensor 4 are respectively connected to the power connector 6, and the closed-loop control system is powered through the power connector 6. Optionally, the power connector 6 can be of the XT60 model.

[0040] Furthermore, the pitch-changing control structure 3 includes a torque input point structure 31, a torque transmission structure 32, and a torque output point structure 33. The torque input point structure 31 includes an integrally formed joystick 311 and an input end block 312. The input end block 312 is fixed at one end of the joystick 311. The input end block 312 is connected to the servo arm / push rod of the servo 2, and drives the joystick 311 to rotate through the movement of the servo arm / push rod; the other end of the joystick 311 is connected to the torque transmission structure 32. The top of the torque transmission structure 32 is connected to a plurality of torque output point structures 33. The rotation of the joystick 311 drives the movement of the torque transmission structure 32. The torque transmission structure 32 transmits the movement to the torque output point structure 33 to drive the movement of the torque output point structure 33; the upper end of each torque output point structure is directly connected to the pitch-changing hinge of the corresponding blade hub of the drone propeller 5. The movement of the torque output point structure 33 drives the movement of the pitch-changing hinge of the blade hub, thereby realizing the change of the blade angle. The pitch-changing control structure of the present invention is a torque transmission structure for amplifying the magnitude of the manipulated input displacement, amplifying the magnitude of the manipulated input force, or converting the arc movement manipulated input into a strictly linear movement output.

[0041] In summary, when the present invention is in use, the wire-pulling displacement sensor 4 measures the displacement of the output point of the pitch-changing control structure 3, and transmits the output point displacement signal to the flight control 1 through the first signal line S and the first signal ground line G. The flight control 1 sends a PWM control signal to the servo 2 through the second signal line S and the second signal ground line G. The servo 2 is connected to the input point of the pitch-changing control structure 3 through a servo arm / push rod, and drives the input point of the pitch-changing control structure 3 to move through the servo arm / push rod. The pitch-changing control structure 3 transmits the input point displacement to the output point, changing the output point displacement; the pitch-changing control structure 3 is also connected to the drone propeller 5, and the displacement changes of the input point and the output point of the pitch-changing control structure 3 realize the blade angle change of the drone propeller 5. Thus, there are both outputs and inputs of signals among the flight control 1, the servo 2, the pitch-changing control structure 3 and the wire-pulling displacement sensor 4, realizing a closed-loop control system.

[0042] Embodiment 2

[0043] As Figure 4 shown, Embodiment 2 of the present invention provides a closed-loop control method for a variable-pitch propeller of a drone, which is applied to a flight control and includes the following steps:

[0044] Step 410: Receive the moving displacement amount of the output point of the pitch-changing control structure collected by the wire-pulling displacement sensor;

[0045] Step 420: Calculate the servo control amount according to the desired blade angle and the moving displacement amount of the output point of the pitch-changing control structure fed back by the wire-pulling displacement sensor;

[0046] Among them, the flight control calculates the size of the blade angle corresponding to the maximum effective power of the engine / motor according to the linear conversion relationship between the propeller blade angle and the flight speed provided by the manufacturer or pre-tested and fitted, and combines the current flight speed of the drone. This blade angle is the desired blade angle.

[0047] In the embodiment of the present invention, as Figure 5 shown, calculating the servo control amount specifically includes the following sub-steps:

[0048] Step 510: Calculate the actual propeller blade angle according to the moving displacement amount of the output point of the pitch-changing control structure fed back by the wire-pulling displacement sensor, and calculate the feedforward of the servo control amount according to the desired blade angle;

[0049] Under the static condition of the drone, the linear conversion relationship between the moving displacement amount of the output point of the pitch-changing control structure and the actual propeller blade angle is obtained through test calibration, that is, W t =α·λ t , W t is the measured moving displacement amount at time t, λ tis the actual blade angle, α is the linear relationship coefficient, which is calibrated by the structure and size of the UAV. According to the linear relationship between the two, when the moving displacement of the output point of the pitch control structure is determined during normal operation, the actual blade angle can be determined.

[0050] And under the static condition of the UAV, the linear conversion relationship between the servo control quantity feedforward and the propeller blade angle is obtained through test calibration. Then, during normal operation, the flight controller calculates the servo control quantity feedforward according to this conversion relationship and in combination with the current desired blade angle.

[0051] Step 520: Calculate the deviation value between the actual blade angle and the desired blade angle;

[0052] The deviation value e(t) between the actual blade angle and the desired blade angle = λ 0 -λ t , λ t is the actual blade angle at time t calculated according to the measured value, and λ 0 is the desired blade angle.

[0053] Step 530: Calculate the servo control quantity compensation according to the deviation between the actual blade angle and the desired blade angle;

[0054] The specific formula for calculating the servo control quantity compensation is:

[0055]

[0056] Among them, μ(t) is the output curve of the servo control quantity compensation changing with time; e(t) is the deviation between the actual blade angle and the desired blade angle; K p is the proportional coefficient of the output servo control quantity to the input deviation value, T i is the integral time; T d is the differential time; K p , T i and T d are obtained through actual debugging or through control modeling and simulation.

[0057] Step 540: Add the servo control quantity feedforward and the servo control quantity compensation to obtain the output of the flight controller servo control quantity.

[0058] Return to see Figure 4 , step 430: Transmit the servo output quantity to the servo.

[0059] Embodiment III

[0060] As Figure 6 shown, Embodiment III of the present invention provides a variable pitch propeller closed-loop control device 60 for a UAV, that is, a flight controller, including a receiving unit 61, a servo control quantity calculation unit 62, and a sending unit 63;

[0061] Among them, the receiving unit 61 receives the moving displacement of the output point of the pitch control structure collected by the wire displacement sensor; the servo control quantity calculation unit 62 calculates the servo control quantity according to the desired blade angle and the moving displacement of the output point of the pitch control structure fed back by the wire displacement sensor; the sending unit 63 transmits the servo output quantity to the servo.

[0062] Specifically, the servo control quantity calculation unit 62 specifically includes an actual propeller blade angle calculation module 621, a servo control quantity feedforward calculation module 622, a blade angle deviation value calculation module 623, a servo control quantity compensation calculation module 624, and a flight control servo control quantity calculation module 625;

[0063] The actual propeller blade angle calculation module 621 calculates the actual propeller blade angle according to the moving displacement of the output point of the pitch control structure fed back by the wire displacement sensor; the servo control quantity feedforward calculation module 622 calculates the servo control quantity feedforward according to the desired blade angle; the blade angle deviation value calculation module 623 is used to calculate the deviation value between the actual blade angle and the desired blade angle; the servo control quantity compensation calculation module 624 calculates the servo control quantity compensation according to the deviation between the actual blade angle and the desired blade angle; the flight control servo control quantity calculation module 625 adds the servo control quantity feedforward and the servo control quantity compensation to obtain the flight control servo control quantity.

[0064] Furthermore, the device further includes an ADC module for converting the analog signal of the moving displacement of the output point of the pitch control structure collected by the wire displacement sensor into a digital signal; and the device further includes a PWM module for converting the calculated flight control servo control quantity into a PWM control signal and transmitting the PWM control signal to the servo.

[0065] Embodiment Four

[0066] As Figure 7 shown, Embodiment Four of the present invention provides a closed-loop control method for a variable pitch propeller of an unmanned aerial vehicle, which is applied to a closed-loop control system and includes the following steps:

[0067] Step 710, the wire displacement sensor collects the moving displacement of the output point of the pitch control structure and feeds back the moving displacement of the output point of the pitch control structure to the flight control;

[0068] Specifically, the wire displacement sensor is connected to the output point of the pitch control structure through a sensor wire to measure the moving displacement of the output point of the pitch control structure. The wire displacement sensor is electrically connected to the flight control. The output of the wire displacement sensor is generally an analog quantity, including current, voltage, resistance signals, etc. The flight control needs to convert the analog signal of the moving displacement measured by the wire displacement sensor into a flight control digital signal through the ADC.

[0069] Step 720: The flight controller calculates the servo control amount based on the expected blade angle and the displacement of the output point of the pitch control structure feedback by the wire displacement sensor, and transmits the servo output amount to the servo;

[0070] Step 730: The servo drives the input point of the pitch control structure to move a corresponding displacement according to the servo control amount;

[0071] Step 740: The pitch control structure transmits the force and displacement of the input point to the output point through the internal structure, changes the displacement of the output point, and thus changes the size of the propeller blade angle.

[0072] Corresponding to the above embodiment, an embodiment of the present invention provides a computer storage medium, including: at least one memory and at least one processor;

[0073] The memory is used to store one or more program instructions;

[0074] The processor is used to run one or more program instructions to execute a closed-loop control method for an unmanned aerial vehicle variable pitch propeller.

[0075] Corresponding to the above embodiment, an embodiment of the present invention provides a computer-readable storage medium, and the computer storage medium contains one or more program instructions, and the one or more program instructions are used to be executed by the processor to execute a closed-loop control method for an unmanned aerial vehicle variable pitch propeller.

[0076] The embodiment disclosed by the present invention provides a computer-readable storage medium, and computer program instructions are stored in the computer-readable storage medium. When the computer program instructions run on a computer, the computer is enabled to execute the above-mentioned closed-loop control method for an unmanned aerial vehicle variable pitch propeller.

[0077] In the embodiment of the present invention, the processor may be an integrated circuit chip with signal processing capabilities. The processor may be a general-purpose processor, a digital signal processor (DSP for short), an application specific integrated circuit (ASIC for short), a field programmable gate array (FPGA for short), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0078] The various methods, steps, and logic block diagrams disclosed in the embodiments of the present invention can be implemented or executed. The general-purpose processor can be a microprocessor, or the processor can also be any conventional processor, etc. The steps of the method disclosed in combination with the embodiments of the present invention can be directly embodied as being executed and completed by a hardware decoding processor, or can be executed and completed by a combination of hardware and software modules in the decoding processor. The software module can be located in a mature storage medium in the art such as random access memory, flash memory, read-only memory, programmable read-only memory, or electrically erasable programmable memory, registers, etc. The processor reads the information in the storage medium and combines its hardware to complete the steps of the above method.

[0079] The storage medium can be a memory, for example, it can be a volatile memory or a non-volatile memory, or can include both volatile and non-volatile memories.

[0080] Among them, the non-volatile memory can be read-only memory (ROM for short), programmable read-only memory (PROM for short), erasable programmable read-only memory (EPROM for short), electrically erasable programmable read-only memory (EEPROM for short), or flash memory.

[0081] The volatile memory can be random access memory (RAM for short), which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory (SRAM for short), dynamic random access memory (DRAM for short), synchronous dynamic random access memory (SDRAM for short), double data rate synchronous dynamic random access memory (DDR SDRAM for short), enhanced synchronous dynamic random access memory (ESDRAM for short), synchronous link dynamic random access memory (SLDRAM for short), and direct rambus random access memory (DRRAM for short).

[0082] The storage media described in the embodiments of the present invention are intended to include but not be limited to these and any other suitable types of memories.

[0083] Those skilled in the art should be able to realize that in one or more of the above examples, the functions described in the present invention can be implemented by a combination of hardware and software. When applying software, the corresponding functions can be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. The computer-readable medium includes computer storage media and communication media, where the communication media includes any medium that facilitates the transfer of a computer program from one place to another. The storage media can be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0084] The specific embodiments described above have further elaborated on the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only the specific embodiments of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made on the basis of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A closed-loop control method for a variable-pitch propeller of an unmanned aerial vehicle, characterized in that, it includes: Receiving the moving displacement of the output point of the variable-pitch control structure collected by the wire displacement sensor; Calculating the servo control quantity according to the desired blade angle and the moving displacement of the output point of the variable-pitch control structure fed back by the wire displacement sensor; Transmitting the servo output quantity to the servo; Calculating the servo control quantity specifically includes the following sub-steps: Calculating the actual propeller blade angle according to the moving displacement of the output point of the variable-pitch control structure fed back by the wire displacement sensor, and calculating the feedforward of the servo control quantity according to the desired blade angle; Calculating the deviation value between the actual blade angle and the desired blade angle; Calculating the servo control quantity compensation according to the deviation between the actual blade angle and the desired blade angle; Adding the servo control quantity feedforward and the servo control quantity compensation to obtain the output of the flight control servo control quantity.

2. The closed-loop control method for a variable-pitch propeller of an unmanned aerial vehicle according to claim 1, characterized in that, The desired blade angle is calculated according to the linear conversion relationship between the propeller blade angle and the flight speed provided by the manufacturer or pre-tested and fitted, and combined with the current flight speed of the unmanned aerial vehicle, to obtain the blade angle corresponding to the maximum effective power of the engine / motor.

3. An unmanned aerial vehicle flight control, characterized in that, It includes a receiving unit, a servo control quantity calculation unit and a sending unit; the receiving unit receives the moving displacement of the output point of the variable-pitch control structure collected by the wire displacement sensor; the servo control quantity calculation unit calculates the servo control quantity according to the desired blade angle and the moving displacement of the output point of the variable-pitch control structure fed back by the wire displacement sensor; the sending unit transmits the servo output quantity to the servo; The servo control quantity calculation unit specifically includes an actual propeller blade angle calculation module, a servo control quantity feedforward calculation module, a blade angle deviation value calculation module, a servo control quantity compensation calculation module and a flight control servo control quantity calculation module; The actual propeller blade angle calculation module calculates the actual propeller blade angle according to the moving displacement of the output point of the variable-pitch control structure fed back by the wire displacement sensor; The servo control quantity feedforward calculation module calculates the servo control quantity feedforward according to the desired blade angle; the blade angle deviation value calculation module is used to calculate the deviation value between the actual blade angle and the desired blade angle; the servo control quantity compensation calculation module calculates the servo control quantity compensation according to the deviation between the actual blade angle and the desired blade angle; the flight control servo control quantity calculation module adds the servo control quantity feedforward and the servo control quantity compensation to obtain the flight control servo control quantity.

4. The unmanned aerial vehicle flight control according to claim 3, characterized in that, It further includes an ADC module for converting the analog signal of the moving displacement of the output point of the variable-pitch control structure collected by the wire displacement sensor into a digital signal.

5. The unmanned aerial vehicle flight control according to claim 3, characterized in that, It further includes a PWM module for converting the calculated flight control servo control quantity into a PWM control signal and transmitting the PWM control signal to the servo.

6. A closed-loop control system for a variable-pitch propeller of an unmanned aerial vehicle, characterized in that, it includes: The unmanned aerial vehicle flight control, servo, variable-pitch control structure and wire displacement sensor according to any one of claims 3-5; One end of the wire-pulling displacement sensor is connected to the output point of the pitch control structure through the sensor wire, and the other end is electrically connected to the flight control; the flight control is electrically connected to the servo motor; The servo motor is connected to the input point of the pitch control structure through the servo arm / push rod; the pitch control structure is also connected to the drone propeller, and the displacement change between the input point and the output point of the pitch control structure drives the change of the propeller blade angle of the drone.

7. A control method for a closed-loop control system of a variable-pitch propeller of a drone, which is applied to the closed-loop control system of a variable-pitch propeller of a drone as described in claim 6, characterized in that, it includes: The wire-pulling displacement sensor collects the moving displacement of the output point of the pitch control structure and feeds back the moving displacement of the output point of the pitch control structure to the flight control; The flight control calculates the servo control amount according to the desired blade angle and the moving displacement of the output point of the pitch control structure fed back by the wire-pulling displacement sensor, and transmits the servo output amount to the servo motor; The servo motor drives the input point of the pitch control structure to move a corresponding displacement according to the servo control amount; The pitch control structure transfers the force and moving displacement of the input point to the output point through the internal structure, changes the moving displacement of the output point, and thus changes the size of the propeller blade angle.

8. A computer storage medium, characterized in that, it includes: at least one memory and at least one processor; The memory is used to store one or more program instructions; The processor is used to run one or more program instructions to execute a closed-loop control method for a variable-pitch propeller of a drone as described in any one of claims 1-2.

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