CN112758315A

CN112758315A - Propeller blade angle adjusting method and device

Info

Publication number: CN112758315A
Application number: CN201911001282.6A
Authority: CN
Inventors: 刘坤甲; 曲岩
Original assignee: Beijing Jingdong Qianshi Technology Co Ltd
Current assignee: Beijing Jingdong Qianshi Technology Co Ltd
Priority date: 2019-10-21
Filing date: 2019-10-21
Publication date: 2021-05-07
Anticipated expiration: 2039-10-21
Also published as: CN112758315B

Abstract

The invention discloses a propeller blade angle adjusting method and device, and relates to the technical field of computers. One embodiment of the method comprises: receiving a switching instruction of a flight mode, and acquiring the rotating speed of an engine in real time, wherein the switching instruction indicates that the current flight mode is switched to a target flight mode; gradually adjusting the blade angle of the propeller under the condition that the collected rotating speed of the engine exceeds the set rotating speed range of the target flight mode; and when the rotating speed of the engine is within the set rotating speed range by adjusting the position of a blade angle, stopping adjusting the blade angle, and calculating to obtain a real-time blade angle value through a blade angle operation model corresponding to the target flight mode. This embodiment can realize the paddle angle adjustment of unmanned aerial vehicle flight in-process and obtain the paddle angle value of screw.

Description

Propeller blade angle adjusting method and device

Technical Field

The invention relates to the technical field of computers, in particular to a propeller blade angle adjusting method and device.

Background

For the propeller navigation aircraft in the current market, a pilot adjusts and sets the propeller blade angle through a controller panel according to own experience and flight states such as flight speed and altitude change so as to change the load of an engine and adjust the rotating speed of the engine, thereby preventing the engine from over-rotating and improving the power output efficiency of the engine. The angle controller who uses on the unmanned aerial vehicle at present generally is reequiped by current controller, does not have the paddle angle controller to unmanned aerial vehicle specially, so current screw angle controller can not satisfy cargo transport unmanned aerial vehicle's actual demand completely.

The existing propeller blade angle controller matched with the navigation aircraft is mainly designed for the manned navigation aircraft, a special control panel circuit is required to be designed for manual configuration, which is completely unnecessary on the unmanned aerial vehicle, and the circuit not only increases the volume and weight of the controller, but also reduces the reliability of the hardware of the controller; at present, for an unmanned plane, a pilot manually adjusts a blade angle at any time according to real-time flight speed, flight height and engine rotating speed, and for the unmanned plane, the blade angle cannot be adjusted during flight; meanwhile, the difficulty of adding the angle sensor on the propeller is very high, the reliability cannot be guaranteed, and the actual angle value of the propeller blade cannot be obtained because the blade angle controller and the propeller blade are not provided with the angle sensor and the acquisition circuit.

In the process of implementing the invention, the inventor finds that at least the following problems exist in the prior art:

the blade angle adjustment can not be carried out on the unmanned aerial vehicle during flying, and the actual angle value of the propeller blade can not be obtained.

Disclosure of Invention

In view of this, embodiments of the present invention provide a propeller blade angle adjusting method and apparatus, which can implement blade angle adjustment in the flight process of an unmanned aerial vehicle and obtain a blade angle value of a propeller.

To achieve the above object, according to one aspect of an embodiment of the present invention, there is provided a propeller blade angle adjustment method.

A method of propeller blade angle adjustment comprising: receiving a switching instruction of a flight mode, and acquiring the rotating speed of an engine in real time, wherein the switching instruction indicates that the current flight mode is switched to a target flight mode; gradually adjusting the blade angle of the propeller under the condition that the collected rotating speed of the engine exceeds the set rotating speed range of the target flight mode; and when the rotating speed of the engine is within the set rotating speed range by adjusting the position of a blade angle, stopping adjusting the blade angle, and calculating to obtain a real-time blade angle value through a blade angle operation model corresponding to the target flight mode.

Optionally, the step of calculating a real-time blade angle value through a blade angle operation model corresponding to the target flight mode includes: and inputting the information of the flight height, the flight speed, the throttle lever position and the engine rotating speed of the airplane obtained in real time into a blade angle operation model corresponding to the target flight mode so as to calculate and obtain the real-time blade angle value.

Optionally, a blade angle calculation model corresponding to a flight mode is obtained by: establishing a power system mathematical model under the flight mode by utilizing the matching relation between the propeller required power and the engine output power, wherein the power system mathematical model comprises a plurality of groups of discrete value sets corresponding to the flight mode, and each group of discrete value sets comprises discrete values of flight height, flight speed, throttle lever position, engine rotating speed and blade angle; and fitting the mathematical model of the power system by using a fitting algorithm to obtain a blade angle operation model corresponding to the flight mode.

Optionally, the step of establishing a mathematical model of the power system in a flight mode by using a matching relationship between the power demand of the propeller and the output power of the engine includes: setting the constant rotating speed of the engine in the flight mode; calculating first fixed blade angle mode power data corresponding to the minimum blade angle, wherein the first fixed blade angle mode power data comprise: the minimum blade angle and the corresponding aircraft flying height, flying speed, throttle lever position and first matching rotating speed of the engine; the first matching rotating speed of the engine is obtained by matching propeller required power with engine output power under the condition of minimum blade angle and is less than or equal to the constant rotating speed of the engine; calculating constant speed mode power data, the constant speed mode power data comprising: a first blade angle of the propeller and the corresponding flying height, flying speed, throttle lever position and constant rotating speed of the engine of the airplane; the first propeller blade angle is a propeller blade angle which is calculated by utilizing the constant rotating speed of the engine, the flying height, the position of the throttle lever, an engine performance curve and a propeller performance curve and is less than or equal to the maximum blade angle, and the engine performance curve represents the relation between engine performance parameters; the propeller performance curves represent relationships between propeller performance parameters; calculating second fixed blade angle mode dynamic data corresponding to the maximum blade angle, wherein the second fixed blade angle mode dynamic data comprises: the maximum blade angle and the corresponding aircraft flying height, flying speed, throttle lever position and second matching rotating speed of the engine; the second matching rotating speed of the engine is obtained by matching the required power of the propeller with the output power of the engine under the condition of the maximum blade angle; and establishing a power system mathematical model under the flight mode according to the first fixed blade angle mode power data, the constant speed mode power data and the second fixed blade angle mode power data.

Optionally, the step of obtaining the engine matching speed by matching the propeller required power with the engine output power comprises: selecting a blade angle, and calculating the required power of the propeller at each flight height and flight speed by using the selected blade angle and a propeller power coefficient characteristic curve, wherein the selected blade angle is the minimum blade angle or the maximum blade angle, and the propeller power coefficient characteristic curve represents the relation between the propeller power coefficient and the propeller advancing distance ratio at different blade angles; and performing power matching by using the calculated propeller required power and an engine power characteristic curve to obtain the engine matching rotating speed and the engine matching power of different throttle lever positions at various flight heights and flight speeds, wherein the engine power characteristic curve represents the relation between the engine output power and the engine rotating speed at different throttle lever positions.

Optionally, the engine performance curve comprises the engine power characteristic curve, the propeller performance curve comprises the propeller power coefficient characteristic curve, a propeller coefficient of tension characteristic curve and a propeller efficiency characteristic curve, and the propeller coefficient of tension characteristic curve represents the relation between the propeller coefficient of tension and the propeller pitch ratio at different blade angles; the propeller efficiency characteristic curve represents the relationship between the propeller efficiency and the propeller pitch ratio under different blade angles; calculating the first blade angle of the propeller by: calculating the output power of the engine under the constant rotating speed of the engine according to the flying heights, the positions of different throttle levers, the constant rotating speed of the engine and the power characteristic curve of the engine; and calculating the advancing distance ratio, the power coefficient, the tension coefficient, the efficiency, the tension and the first blade angle of the propeller by utilizing the constant rotating speed of the engine and the corresponding output power of the engine, the flying height and the flying speed, the power coefficient characteristic curve of the propeller, the tension coefficient characteristic curve of the propeller and the efficiency characteristic curve of the propeller.

Optionally, the switching instruction of the flight mode is received from a flight control computer through a serial communication interface, the flight height, the flight speed and the throttle lever position information of the airplane are obtained in real time, and the calculated real-time blade angle value is fed back to the flight control computer for display.

According to another aspect of an embodiment of the present invention, a propeller blade angle adjustment apparatus is provided.

A propeller blade angle adjustment device comprising: the communication module is used for receiving a switching instruction of a flight mode, wherein the switching instruction indicates that the current flight mode is switched to a target flight mode; the rotating speed acquisition module is used for acquiring the rotating speed of the engine in real time; the core processing module is used for sending an adjusting instruction to the propeller to gradually adjust the blade angle of the propeller under the condition that the rotating speed of the engine acquired by the rotating speed acquisition module exceeds the set rotating speed range of the target flight mode; and when the rotating speed of the engine is within the set rotating speed range by adjusting the position of a blade angle, stopping adjusting the blade angle, and calculating to obtain a real-time blade angle value through a blade angle operation model corresponding to the target flight mode.

Optionally, the core processing module is further configured to: and inputting the information of the flight height, the flight speed, the throttle lever position and the engine rotating speed of the airplane obtained in real time into a blade angle operation model corresponding to the target flight mode so as to calculate and obtain the real-time blade angle value.

Optionally, the system further comprises a blade angle operation model building module, configured to: obtaining a blade angle operation model corresponding to a flight mode by the following method: establishing a power system mathematical model under the flight mode by utilizing the matching relation between the propeller required power and the engine output power, wherein the power system mathematical model comprises a plurality of groups of discrete value sets corresponding to the flight mode, and each group of discrete value sets comprises discrete values of flight height, flight speed, throttle lever position, engine rotating speed and blade angle; and fitting the mathematical model of the power system by using a fitting algorithm to obtain a blade angle operation model corresponding to the flight mode.

Optionally, the blade angle operation model building module includes a power system mathematical model building submodule configured to: setting the constant rotating speed of the engine in the flight mode; calculating first fixed blade angle mode power data corresponding to the minimum blade angle, wherein the first fixed blade angle mode power data comprise: the minimum blade angle and the corresponding aircraft flying height, flying speed, throttle lever position and first matching rotating speed of the engine; the first matching rotating speed of the engine is obtained by matching propeller required power with engine output power under the condition of minimum blade angle and is less than or equal to the constant rotating speed of the engine; calculating constant speed mode power data, the constant speed mode power data comprising: a first blade angle of the propeller and the corresponding flying height, flying speed, throttle lever position and constant rotating speed of the engine of the airplane; the first propeller blade angle is a propeller blade angle which is calculated by utilizing the constant rotating speed of the engine, the flying height, the position of the throttle lever, an engine performance curve and a propeller performance curve and is less than or equal to the maximum blade angle, and the engine performance curve represents the relation between engine performance parameters; the propeller performance curves represent relationships between propeller performance parameters; calculating second fixed blade angle mode dynamic data corresponding to the maximum blade angle, wherein the second fixed blade angle mode dynamic data comprises: the maximum blade angle and the corresponding aircraft flying height, flying speed, throttle lever position and second matching rotating speed of the engine; the second matching rotating speed of the engine is obtained by matching the required power of the propeller with the output power of the engine under the condition of the maximum blade angle; and establishing a power system mathematical model under the flight mode according to the first fixed blade angle mode power data, the constant speed mode power data and the second fixed blade angle mode power data.

Optionally, the power system mathematical model building submodule includes a power matching unit for: selecting a blade angle, and calculating the required power of the propeller at each flight height and flight speed by using the selected blade angle and a propeller power coefficient characteristic curve, wherein the selected blade angle is the minimum blade angle or the maximum blade angle, and the propeller power coefficient characteristic curve represents the relation between the propeller power coefficient and the propeller advancing distance ratio at different blade angles; and performing power matching by using the calculated propeller required power and an engine power characteristic curve to obtain the engine matching rotating speed and the engine matching power of different throttle lever positions at various flight heights and flight speeds, wherein the engine power characteristic curve represents the relation between the engine output power and the engine rotating speed at different throttle lever positions.

Optionally, the engine performance curve comprises the engine power characteristic curve, the propeller performance curve comprises the propeller power coefficient characteristic curve, a propeller coefficient of tension characteristic curve and a propeller efficiency characteristic curve, and the propeller coefficient of tension characteristic curve represents the relation between the propeller coefficient of tension and the propeller pitch ratio at different blade angles; the propeller efficiency characteristic curve represents the relationship between the propeller efficiency and the propeller pitch ratio under different blade angles; the power system mathematical model construction submodule comprises a calculation unit, and is used for: calculating the output power of the engine under the constant rotating speed of the engine according to the flying heights, the positions of different throttle levers, the constant rotating speed of the engine and the power characteristic curve of the engine; and calculating the advancing distance ratio, the power coefficient, the tension coefficient, the efficiency, the tension and the first blade angle of the propeller by utilizing the constant rotating speed of the engine and the corresponding output power of the engine, the flying height and the flying speed, the power coefficient characteristic curve of the propeller, the tension coefficient characteristic curve of the propeller and the efficiency characteristic curve of the propeller.

According to yet another aspect of an embodiment of the present invention, an electronic device is provided.

An electronic device, comprising: one or more processors; a memory for storing one or more programs which, when executed by the one or more processors, cause the one or more processors to implement the propeller blade angle adjustment method provided by the present invention.

According to yet another aspect of an embodiment of the present invention, a computer-readable medium is provided.

A computer-readable medium, on which a computer program is stored which, when being executed by a processor, carries out the method of propeller blade angle adjustment according to the present invention.

One embodiment of the above invention has the following advantages or benefits: acquiring the rotating speed of an engine in real time, and gradually adjusting the blade angle of a propeller under the condition that the acquired rotating speed of the engine exceeds the set rotating speed range of the target flight mode; and when the blade angle position is adjusted to enable the rotating speed of the engine to be within the set rotating speed range, stopping adjusting the blade angle. Can realize the paddle angle modulation of unmanned aerial vehicle flight in-process. And inputting the information of the flight height, the flight speed, the throttle lever position and the engine rotating speed of the airplane obtained in real time into a blade angle operation model corresponding to the target flight mode so as to calculate the real-time blade angle value. Therefore, the blade angle value of the propeller can be obtained under the condition of no blade angle position sensor.

Further effects of the above-mentioned non-conventional alternatives will be described below in connection with the embodiments.

Drawings

The drawings are included to provide a better understanding of the invention and are not to be construed as unduly limiting the invention. Wherein:

FIG. 1 is a schematic diagram of the main steps of a method of adjusting the angle of a propeller blade according to a first embodiment of the present invention;

FIG. 2 is a schematic diagram of the main steps of a method of adjusting the angle of a propeller blade according to a second embodiment of the present invention;

FIG. 3 is a schematic flow chart of a mathematical model of a constant-speed variable-pitch power system according to a third embodiment of the invention;

FIG. 4 is a graphical illustration of a propeller power coefficient characteristic in accordance with an embodiment of the present invention;

FIG. 5 is a schematic representation of an engine power characteristic according to an embodiment of the present invention;

FIG. 6 is a graphical representation of a coefficient of drag characteristic of a propeller according to an embodiment of the present invention;

FIG. 7 is a schematic representation of a propeller efficiency characteristic according to an embodiment of the present invention;

FIG. 8 is a schematic view of a propeller blade angle adjustment and angle value feedback process according to a fourth embodiment of the present invention;

FIG. 9 is a schematic block diagram of the main components of a propeller blade angle adjustment apparatus according to a fifth embodiment of the present invention;

FIG. 10 is a schematic hardware configuration diagram of a propeller blade angle adjustment apparatus according to a sixth embodiment of the present invention;

FIG. 11 is an exemplary system architecture diagram in which embodiments of the present invention may be employed;

fig. 12 is a schematic structural diagram of a computer system suitable for implementing a terminal device or a server according to an embodiment of the present invention.

Detailed Description

Exemplary embodiments of the present invention are described below with reference to the accompanying drawings, in which various details of embodiments of the invention are included to assist understanding, and which are to be considered as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. Also, descriptions of well-known functions and constructions are omitted in the following description for clarity and conciseness.

As will be appreciated by one skilled in the art, embodiments of the present invention may be embodied as a system, apparatus, device, method, or computer program product. Accordingly, the present disclosure may be embodied in the form of: entirely hardware, entirely software (including firmware, resident software, micro-code, etc.), or a combination of hardware and software.

The propeller blade angle adjusting method provided by the embodiment of the invention can be used for adjusting the propeller blade angle of an unmanned aerial vehicle, such as the propeller blade angle of various unmanned aerial vehicles such as a freight unmanned aerial vehicle.

Fig. 1 is a schematic view of the main steps of a propeller blade angle adjustment method according to a first embodiment of the present invention.

As shown in fig. 1, the propeller blade angle adjustment method of the first embodiment of the present invention mainly includes steps S101 to S103 as follows.

Step S101: and receiving a switching instruction of the flight mode, acquiring the rotating speed of the engine in real time, and switching the current flight mode into the target flight mode by the switching instruction.

The unmanned aerial vehicle provided by the embodiment of the invention does not need a control panel circuit, and according to the difference of the flight phases of the unmanned aerial vehicle, the flight modes (namely the control mode of flight, also called constant-speed variable pitch mode) can comprise a takeoff mode, a climbing mode and a cruise mode, the control strategies in the different modes are set up before the unmanned aerial vehicle takes off, and the flight control computer automatically switches the flight modes in the flight process. The switching instruction of the flight mode sent by the flight control computer can be received through a serial communication interface (such as an RS422 interface).

Step S102: and gradually adjusting the blade angle of the propeller under the condition that the rotating speed of the engine acquired in real time exceeds the set rotating speed range of the target flight mode.

Step S103: and when the blade angle position is adjusted to enable the rotating speed of the engine to be within a set rotating speed range, stopping adjusting the blade angle.

The propeller provided by the embodiment of the invention is an electric constant-speed variable-pitch propeller, the blade angle of the propeller is changed by a servo motor in the propeller according to the flying high speed and flying speed change of the unmanned aerial vehicle, so that the rotating speed of an engine is kept constant, and the effective power of the engine is fully utilized.

By collecting the analog signal of the engine speed, a closed-loop constant speed mode can be realized. In the constant speed variable pitch mode, the engine speed value is used as a closed-loop control reference value. In the mode, the constant-speed variable-pitch rotating speed of the engine can be set according to flight requirements. The control procedures of step S102 and step S103 are specifically as follows: when the actual value of the rotating speed of the engine acquired in real time exceeds the error range of the set value (namely the set rotating speed range of the target flight mode), starting adjustment; when the actual value of the rotating speed of the engine is smaller than the lower limit of the error range of the set value, the angle of the paddle is gradually reduced; when the actual value of the rotating speed of the engine is larger than the upper limit of the error range of the set value, gradually increasing the angle of the blade; and stopping the regulation when the actual value of the engine speed is within the error range of the set value.

The takeoff mode, the climbing mode and the cruise mode can be respectively provided with different rotating speeds of the constant speed mode, and each mode is provided with an error range, namely a set rotating speed range, for example, the set rotating speed is X (X represents a numerical value), and the corresponding error range is [ X-50, X +50 ]. According to the embodiment of the invention, in the flight phase of the unmanned aerial vehicle, the flight control computer can switch modes according to the real-time flight state of the unmanned aerial vehicle.

Fig. 2 is a schematic view of the main steps of a propeller blade angle adjustment method according to a second embodiment of the present invention.

The propeller blade angle adjustment method of the second embodiment of the present invention mainly includes steps S201 to S204 as follows. Step S201 is the same as step S101, step S202 is the same as step S102, and step S203 is the same as step S103, so that steps S201 to S203 refer to the description of the corresponding steps of the first embodiment, and are not repeated here.

Step S204: and calculating to obtain a real-time blade angle value through a blade angle operation model corresponding to the target flight mode.

Step S204 may specifically include: and inputting the information of the flight height, the flight speed, the throttle lever position and the engine rotating speed of the airplane obtained in real time into a blade angle operation model corresponding to the target flight mode so as to calculate and obtain the real-time blade angle value.

The flight height, the flight speed and the throttle lever position information of the airplane can be obtained in real time through the serial communication interface, and the calculated real-time blade angle value is fed back to the flight control computer to be displayed conveniently. The real-time blade angle value is adjusted to a blade angle position, so that the corresponding blade angle value is obtained when the rotating speed of the engine is within a set rotating speed range.

The blade angle operation model comprises a functional relation between the propeller blade angle and the flying height, flying speed, throttle lever position and engine rotating speed of the airplane.

The blade angle operation model corresponding to a certain flight mode can be obtained through the following modes:

establishing a power system mathematical model under the flight mode by utilizing the matching relation between the propeller required power and the engine output power, wherein the power system mathematical model comprises a plurality of groups of discrete value sets corresponding to the flight mode, each group of discrete value sets comprises discrete values of flight height, flight speed, throttle lever position, engine rotating speed and blade angle, and also comprises discrete values of parameters such as engine output power, and the advance ratio, power coefficient, tension coefficient, efficiency and the like of the propeller;

and fitting the mathematical model of the power system by using a fitting algorithm to obtain a blade angle operation model corresponding to the flight mode.

Fitting algorithms such as least squares.

The following describes a process of establishing a mathematical model of the power system in a certain flight mode by using the matching relationship between the propeller required power and the engine output power.

The constant engine speed in this flight mode is set.

Calculating first fixed blade angle mode power data corresponding to the minimum blade angle, wherein the first fixed blade angle mode power data comprise: the minimum blade angle and the corresponding aircraft flying height, flying speed, throttle lever position and first matching rotating speed of the engine.

The first matching rotating speed of the engine is the engine matching rotating speed which is obtained by matching the required power of the propeller with the output power of the engine and is less than or equal to the constant rotating speed of the engine under the condition of the minimum blade angle.

Calculating constant speed mode power data, the constant speed mode power data comprising: the first blade angle of the propeller and the corresponding flight height, flight speed, throttle lever position and constant rotating speed of the engine of the airplane.

The first propeller blade angle is calculated by using the constant rotating speed of the engine, the flying height, the position of the throttle lever, the performance curve of the engine and the performance curve of the propeller and is smaller than or equal to the maximum propeller blade angle.

The engine performance curve represents a relationship between engine performance parameters; the propeller performance curve represents the relationship between propeller performance parameters.

Specifically, the engine performance curve includes an engine power characteristic curve. The engine power characteristic curve represents the relationship between the engine output power and the engine rotating speed under different throttle lever positions.

The propeller performance curve comprises a propeller power coefficient characteristic curve, a propeller tension coefficient characteristic curve and a propeller efficiency characteristic curve. The characteristic curve of the power coefficient of the propeller represents the relationship between the power coefficient of the propeller and the advancing distance ratio of the propeller under different blade angles; the characteristic curve of the propeller tension coefficient represents the relationship between the propeller tension coefficient and the propeller pitch ratio under different blade angles; the propeller efficiency characteristic curve represents the relationship between the propeller efficiency and the propeller pitch ratio under different blade angles.

Specifically, the first blade angle of the propeller is calculated by the following method:

calculating the output power of the engine under the constant rotating speed of the engine according to the flying heights, different throttle lever positions, the constant rotating speed of the engine and the power characteristic curve of the engine;

and calculating the advancing distance ratio, the power coefficient, the tension coefficient, the efficiency, the tension and the first blade angle of the propeller by utilizing the constant rotating speed of the engine and the corresponding output power, the flying height and the flying speed of the engine, the power coefficient characteristic curve of the propeller, the tension coefficient characteristic curve of the propeller and the efficiency characteristic curve of the propeller.

Calculating second fixed blade angle mode power data corresponding to the maximum blade angle, wherein the second fixed blade angle mode power data comprises the following steps: the maximum blade angle and the corresponding aircraft flying height, flying speed, throttle lever position and second matching rotating speed of the engine.

And the second matching rotating speed of the engine is the matching rotating speed of the engine obtained by matching the required power of the propeller with the output power of the engine under the condition of the maximum blade angle.

The step of obtaining the engine matching rotating speed by matching the propeller required power with the engine output power specifically comprises:

selecting a blade angle, and calculating the required power of the propeller at each flight height and flight speed by using the selected blade angle and the characteristic curve of the power coefficient of the propeller, wherein the selected blade angle is the minimum blade angle or the maximum blade angle;

and performing power matching by using the calculated propeller required power and the engine power characteristic curve to obtain the engine matching rotating speed and the engine matching power at different throttle lever positions at various flight heights and flight speeds.

And establishing a power system mathematical model under the flight mode according to the first fixed blade angle mode power data, the constant speed mode power data and the second fixed blade angle mode power data. The mathematical model of the power system reflects parameters of the power system, such as rotating speed (namely rotating speed of an engine), blade angle, pulling force and the like, when the power system is at different flying heights, flying speeds and throttle lever positions.

Fig. 3 is a schematic flow chart of the construction of a mathematical model of a constant-speed variable-pitch power system according to a third embodiment of the invention.

In order to obtain the real-time blade angle value of the propeller in the constant-speed variable-pitch mode, the corresponding relation between the performance of the power system and the blade angle of the propeller needs to be established. The construction process of the mathematical model of the power system according to the embodiment of the present invention is described in detail below.

Before building a mathematical model of the powertrain system, the engine characteristics and propeller characteristics need to be solved. The engine characteristics mainly comprise full throttle and partial throttle characteristics, namely the power which can be generated by the engine under different throttle lever positions and at different rotating speeds; the characteristics of the propeller mainly relate to the tension coefficient, the power system, the efficiency and the advance ratio of the propeller under different blade angles. By matching the power of the engine and the propeller, performance parameters such as the corresponding engine rotating speed, propeller tension, blade angle value and the like can be calculated when different flying heights, different flying speeds and different throttle lever positions are adopted. The power matching state of the engine and the propeller refers to a stable state when the output power of the engine and the power required by the propeller reach balance.

In a certain flight mode, the construction process of the mathematical model of the constant-speed variable-pitch power system (abbreviated as the mathematical model of the power system) includes the following steps S301 to S311. The flight mode may be any one of a takeoff mode, a climb mode, a cruise mode.

Step S301: the constant speed of the engine in a certain flight mode is set and the maximum blade angle and the minimum blade angle of the propeller are determined.

Step S302: and performing fixed blade angle mode calculation of the minimum blade angle, wherein the required power of the propeller under a certain flight height and flight speed under the condition of the minimum blade angle of the propeller is calculated by using a propeller power coefficient characteristic curve.

The characteristic curve of the power coefficient of the propeller is shown in FIG. 4, which represents the relationship between the power coefficient of the propeller and the advancing distance ratio of the propeller under different blade angles, and the power of the propellerThe abscissa axis of the coefficient characteristic curve is the propeller pitch ratio J; the ordinate axis being the power coefficient C of the propeller_P(ii) a In fig. 4, 12 curves correspond to 12 different blade angles, and the blade angle values of the 12 curves from bottom to top (curves corresponding to curve numbers 1 to 12) are 14 ° to 25 °, respectively. The number corresponding to the endpoint of each curve is the curve number of the curve.

The specific calculation process of the propeller required power is as follows: substituting different flight speeds V, propeller diameters D and different engine rotating speeds N (transmission ratio relation exists between the propeller rotating speed N and the engine rotating speed N) into a calculation formula of a propeller advancing distance ratio J:

thereby calculating the propeller pitch ratio J. Inquiring a propeller power coefficient characteristic curve according to the propeller pitch ratio J obtained by calculation to obtain a propeller power coefficient C_P。

Substituting the air density rho and the propeller diameter D under the flying height into a propeller power coefficient C_PThe calculation formula of (2):

thereby calculating the required power P of the propeller.

Step S303: and performing power matching by using the power required by the propeller and the power characteristic curve of the engine, and calculating the matching rotating speed and the matching power of the engine at different throttle lever positions under the flying height and the flying speed of the engine.

The engine matching rotating speed refers to the rotating speed of the engine which stably runs under the power matching state of the engine and the propeller; the engine matching power refers to the engine output power of the engine and the propeller in a power matching state.

The engine power characteristic is shown in fig. 5, which shows the relationship between engine output (indicated by P) and engine speed (indicated by N) for different throttle positions. The abscissa axis of the engine power characteristic curve is the engine speed (unit: rpm), and the ordinate axis is the engine output power (unit: KW). Each curve in fig. 5 corresponds to one throttle lever position, and the throttle lever positions corresponding to 10 curves from bottom to top (corresponding to the numbers of the curves from 1 to 10 in the figure) are respectively 10% to 100%. The number corresponding to the endpoint of each curve is the curve number of the curve.

When the power of the engine and the propeller are balanced and the engine stably runs at a certain rotating speed, the matching rotating speed N of the engine is obtained₁Matching the speed N according to the engine₁Inquiring the power characteristic curve of the engine to obtain the matching power P of the engine₁。

Step S304: and calculating the propeller advancing distance ratio, the power coefficient, the tension coefficient, the propeller efficiency and the propeller tension at different throttle lever positions by utilizing the engine matching rotating speed and the engine matching power, the flight height and the flight speed at different throttle lever positions, the propeller power coefficient characteristic curve, the propeller tension coefficient characteristic curve and the propeller efficiency characteristic curve.

The coefficient of tension characteristic of the propeller is shown in fig. 6, which shows the relationship between the coefficient of tension of the propeller and the pitch ratio of the propeller at different blade angles. The abscissa of the characteristic curve of the coefficient of tension of the propeller is the advancing distance ratio J of the propeller and the ordinate is the coefficient of tension C of the propeller_t. Each curve in fig. 6 corresponds to one blade angle, and 12 curves correspond to blade angles of 14 ° to 25 ° from bottom to top (curves numbered from 1 to 12). The number corresponding to the endpoint of each curve is the curve number of the curve.

The propeller efficiency characteristic is shown in fig. 7, which shows the relationship between propeller efficiency and propeller pitch ratio at different blade angles. The abscissa of the propeller efficiency characteristic curve is the propeller advance ratio J, and the ordinate is the propeller efficiency eta. Each curve in fig. 7 corresponds to one blade angle, and the blade angles corresponding to 9 curves from bottom to top (i.e., the curves corresponding to the curve numbers 1 to 9) are 11 °, 13 °, 14 °, 15 °, 17 °, 20 °, 22 °, 24 °, and 25 °, respectively. The number corresponding to the endpoint of each curve is the curve number of the curve.

Matching the flying speed V and the engine with the rotating speed N₁Substituting the propeller diameter D into a calculation formula of a propeller pitch ratio J (according to the transmission ratio relation between the propeller rotating speed N and the engine rotating speed N, the rotating speed N can be matched by the engine₁Obtaining a corresponding propeller speed n):

thereby calculating the advancing distance ratio of the propeller and recording the advancing distance ratio as J₁. The propeller pitch ratio J is obtained according to calculation₁Inquiring the characteristic curve of the power coefficient of the propeller to obtain the power coefficient C of the propeller_P1。

Inquiring the characteristic curve of the tension coefficient of the propeller to obtain the tension coefficient C of the propeller_t。

Then matching the engine with the rotating speed N₁Propeller diameter D, air density rho at flying height, substituting into propeller tension coefficient C_tIs calculated (the rotational speed N can be matched by the engine according to the transmission ratio relationship between the propeller rotational speed N and the engine rotational speed N₁Obtaining a corresponding propeller speed n):

thereby determining the propeller tension T.

According to the calculated propeller advancing distance ratio J₁And inquiring a propeller efficiency characteristic curve to obtain the propeller efficiency eta. Alternatively, the propeller efficiency η may be calculated according to the following formula:

step S305: matching engine rotating speed which is less than or equal to the constant rotating speed of the engine and corresponding flying height, flying speed, throttle lever position, engine output power (here, engine matching power), advancing distance ratio, power coefficient, blade angle (here, minimum blade angle), tension coefficient, efficiency and tension of the corresponding propeller are arranged into fixed blade angle mode power data corresponding to the minimum blade angle.

Step S306: and calculating a constant speed variable pitch mode for the part of the engine with the matched rotating speed greater than the constant rotating speed of the engine, and firstly calculating the output power of the engine under the constant rotating speed of the engine according to the flying height, the throttle lever position, the constant rotating speed of the engine and an engine power characteristic curve.

According to constant speed N of engine₀Inquiring the power characteristic curve of the engine to obtain the output power P of the engine at constant rotating speed₀。

Step S307: and calculating the advancing distance ratio, the power coefficient, the tension coefficient and the blade angle, the efficiency and the tension of the propeller by utilizing the constant rotating speed of the engine and the corresponding output power of the engine as well as the flight altitude, the flight speed, the power coefficient curve of the propeller, the tension coefficient curve and the efficiency characteristic curve.

The engine is kept at a constant rotating speed N₀The flight speed V and the diameter D of the propeller are substituted into a calculation formula of the propeller pitch ratio J:

thereby calculating the advancing distance ratio of the propeller and recording the advancing distance ratio as J₃。

The engine is kept at a constant rotating speed N₀And corresponding engine output power P₀Substituting the air density rho under the flying height into the propeller power coefficient C_PThe calculation formula of (2):

thereby calculating the power coefficient of the propeller and recording the power coefficient as C_P0. Then according to C_P0The corresponding blade angle can be obtained by inquiring the characteristic curve of the propeller power coefficient and is recorded as theta. Of the blade angles, the blade angle of the propeller less than the maximum blade angle is called the first blade angle of the propeller and is denoted by θ₁。

According to the blade angle theta and the advancing distance ratio J of the propeller₃Inquiring the characteristic curve of the coefficient of tension of the propeller to obtain the coefficient of tension of the propeller, and recording the coefficient of tension as C_t0。

Then the air density rho and the constant rotating speed N of the engine under the flying height are measured₀Coefficient of propeller tension C_t0Propeller diameter D, substituting into propeller tension coefficient C_tIs calculated (the engine can be used to keep the rotational speed N constant according to the transmission ratio relation between the propeller rotational speed N and the engine rotational speed N₀Obtaining a corresponding propeller speed n):

and calculating the propeller tension T.

According to the advancing distance ratio J of the propeller₃And inquiring a propeller efficiency characteristic curve to obtain the propeller efficiency eta according to the propeller blade angle theta. Alternatively, the propeller efficiency η may be calculated according to the following formula:

step S308: and (3) arranging the first blade angle of the propeller and the corresponding engine rotating speed (namely the constant rotating speed of the engine), the flying height, the flying speed, the throttle lever position, the output power of the engine, the advancing distance ratio, the power coefficient, the tension coefficient, the efficiency and the tension of the corresponding propeller into constant-speed mode power data.

Step S309: for the part larger than the maximum blade angle calculated in step S307, the fixed blade angle mode calculation of the maximum blade angle is performed, including calculation of the flying height, the flying speed, the throttle lever position, the engine speed, the engine output power, and the advancing distance ratio, the power coefficient, the drag coefficient, the efficiency, and the drag of the propeller corresponding to the maximum blade angle.

The fixed blade angle mode calculation for the maximum blade angle is similar to the method described above for the fixed blade angle mode calculation for the minimum blade angle. Specifically, a maximum blade angle is obtained, and the required power of the propeller at a certain flight height and flight speed at the maximum blade angle of the propeller is calculated by using a propeller power coefficient characteristic curve; the power matching is carried out by utilizing the power required by the propeller and the power characteristic curve of the engine, and the matching rotating speed N of the engine at different throttle lever positions under the flying height and the flying speed of the engine is calculated₂Matched power P₂(ii) a And calculating the advancing distance ratio, the power coefficient, the tension coefficient, the propeller efficiency and the propeller tension of the propellers at different throttle lever positions at the moment by using the calculated matching rotating speed and matching power of the engine at different throttle lever positions, the calculated flying height, flying speed, the calculated propeller power coefficient characteristic curve, the calculated tension coefficient characteristic curve and the calculated efficiency characteristic curve.

Step S310: and (4) arranging the maximum blade angle and the corresponding flying height, flying speed, throttle lever position, engine rotating speed, engine output power, advancing distance ratio, power coefficient, tension coefficient, efficiency and tension of the propeller into fixed blade angle mode power data corresponding to the maximum blade angle.

Wherein the engine speed is the above matching speed N₂The engine rotating speeds are all larger than the set constant rotating speed N₀. Because, to maintain a constant engine speed, this part of the blade angle already exceeds the maximum blade angle. However, the maximum blade angle is not actually exceeded due to the limitation of the blade angle of the propeller, and the maximum blade angle can only be maintained, so that the engine speed N is equal to the engine speed₂Greater than constant speed N₀。

Engine output power, i.e. the above-mentioned matching power P₂。

Step S311: and combining the fixed blade angle mode power data corresponding to the minimum blade angle, the constant speed mode power data and the fixed blade angle mode power data corresponding to the maximum blade angle to obtain the mathematical model of the constant speed variable pitch power system.

FIG. 8 is a schematic view of a propeller blade angle adjustment and angle value feedback process according to a fourth embodiment of the present invention.

The propeller blade angle adjustment process of the fourth embodiment of the present invention mainly includes the following steps S801 to S804

Step S801: obtaining the characteristics of the full throttle and partial throttle of the engine and the performance curve of the propeller

The engine characteristics are mainly full throttle and partial throttle characteristics, namely the power which can be generated by the engine at different rotating speeds under different throttle lever positions, wherein the relationship between the output power (represented by P) of the engine and the rotating speed (represented by N) of the engine under different throttle lever positions can be represented by an engine power characteristic curve. The engine power characteristic curve and the propeller performance curve are respectively associated with the engine characteristic and the propeller characteristic, and may be stored and read in advance.

Step S802: and matching the power of the engine and the power of the propeller, establishing a mathematical model of the power system in a constant-speed variable pitch mode, and obtaining the values of the rotating speed, the pulling force and the angle of the blade angle of the power system when the flying height, the flying speed and the position of the throttle lever are different.

The process of establishing the mathematical model of the powertrain in the constant speed and variable pitch mode is described in detail above, and will not be described herein again. Part of the power calculation data (including the fixed blade angle mode power data corresponding to the minimum blade angle, the constant speed mode power data and the fixed blade angle mode power data corresponding to the maximum blade angle) at different heights, flight speeds and throttle lever positions in the mathematical model of the power system is shown in table 1 (for example only).

TABLE 1

Step S803: and fitting a multivariate function between the angle value of the blade angle and the flying height, the flying speed, the position of the throttle lever and the rotating speed of the engine according to a least square method.

The fitted example function is for example of the form:

N＝3326.54+849.554*Math.Pow(Th,0.5)+0.0028461*Math.Pow(H,1.5)+0.000865497*Math.Pow(V,3)-637.023*Math.Log(Beta)+0.000465707*Math.Pow(H,1.5)*Math.Pow(Th,0.5)-0.00156242*Math.Pow(H,1.5)*Math.Log(Beta)-8.39518/1000000*Math.Pow(V,3)*Math.Pow(Th,0.5)-0.000234287*Math.Pow(V,3)*Math.Log(Beta)-9.75166*Math.Pow(Math.Pow(Th,0.5),2)-152.341*Math.Pow(Th,0.5)*Math.Log(Beta)；

wherein, the variables in the fitted arithmetic function are described as follows:

n: engine speed (rpm, revolutions per minute);

th: throttle lever position (%);

h: flight height (m, meters);

v: flight speed (km/h );

beta: blade angle (degrees, deg.).

Pow (x, y) may return a value to the power of y of x.

Log (x) may return logx.

Step S804: and feeding back the angle value of the blade angle to the flight control computer in real time according to the real-time flight height, flight speed, throttle lever position and engine rotating speed of the unmanned aerial vehicle.

The flight speed, the flight altitude, the position of an engine throttle lever and the rotating speed of the engine can be obtained in real time through the RS422 serial communication interface, the blade angle of the propeller is obtained through a function of the blade angle of the propeller brought into fitting, and the value of the blade angle is fed back to the flight control computer. The flight control computer can display the angle values of the propeller blade angles of different flight states and positions of the throttle lever of the engine. Therefore, the current propeller blade angle is calculated under the condition that a blade angle sensor is not added.

Fig. 9 is a main block schematic diagram of a propeller blade angle adjustment apparatus according to a fifth embodiment of the present invention.

The propeller blade angle adjustment apparatus 900 according to the fifth embodiment of the present invention mainly includes: a communication module 901, a rotating speed acquisition module 902 and a core processing module 903.

The communication module 901 is configured to receive a switching instruction of a flight mode, where the switching instruction indicates to switch a current flight mode to a target flight mode.

And the rotating speed acquisition module 902 is used for acquiring the rotating speed of the engine in real time.

The core processing module 903 is used for sending an adjusting instruction to the propeller to gradually adjust the blade angle of the propeller under the condition that the rotating speed of the engine acquired by the rotating speed acquiring module 902 exceeds the set rotating speed range of the target flight mode; and when the rotating speed of the engine is within a set rotating speed range by adjusting the position of a blade angle, stopping adjusting the blade angle, and calculating to obtain a real-time blade angle value through a blade angle operation model corresponding to the target flight mode.

The core processing module 903 is further configured to: and inputting the information of the flight height, the flight speed, the throttle lever position and the engine rotating speed of the airplane obtained in real time into a blade angle operation model corresponding to the target flight mode so as to calculate and obtain the real-time blade angle value, wherein the blade angle operation model comprises the functional relation between the propeller blade angle and the flight height, the flight speed, the throttle lever position and the engine rotating speed of the airplane.

The propeller blade angle adjustment apparatus 900 may further include a blade angle operation model building module for: obtaining a blade angle operation model corresponding to a flight mode by the following method: establishing a mathematical model of the power system in the flight mode by utilizing the matching relation between the propeller required power and the engine output power, wherein the mathematical model of the power system comprises a plurality of groups of discrete value sets corresponding to the flight mode, and each group of discrete value sets comprises discrete values of flight height, flight speed, throttle lever position, engine rotating speed and blade angle; and fitting the mathematical model of the power system by using a fitting algorithm to obtain a blade angle operation model corresponding to the flight mode.

The blade angle operation model building module can comprise a power system mathematical model building submodule for:

setting the constant rotating speed of the engine in the flight mode; calculating first fixed blade angle mode power data corresponding to the minimum blade angle, wherein the first fixed blade angle mode power data comprise: the minimum blade angle and the corresponding aircraft flying height, flying speed, throttle lever position and first matching rotating speed of the engine; the first matching rotating speed of the engine is the matching rotating speed of the engine which is obtained by matching the power required by the propeller with the output power of the engine and is less than or equal to the constant rotating speed of the engine under the condition of the minimum blade angle;

calculating constant speed mode power data, the constant speed mode power data comprising: a first blade angle of the propeller and the corresponding flying height, flying speed, throttle lever position and constant rotating speed of the engine of the airplane; the first propeller blade angle of the propeller is a propeller blade angle which is calculated by utilizing the constant rotating speed of an engine, the flying height, the position of an accelerator lever, an engine performance curve and a propeller performance curve and is less than or equal to the maximum propeller blade angle, and the engine performance curve represents the relation between engine performance parameters; the propeller performance curve represents the relationship between propeller performance parameters;

calculating second fixed blade angle mode power data corresponding to the maximum blade angle, wherein the second fixed blade angle mode power data comprises the following steps: the maximum blade angle and the corresponding aircraft flying height, flying speed, throttle lever position and second matching rotating speed of the engine; the second matching rotating speed of the engine is the engine matching rotating speed obtained by matching the power required by the propeller with the output power of the engine under the condition of the maximum blade angle;

and establishing a power system mathematical model under the flight mode according to the first fixed blade angle mode power data, the constant speed mode power data and the second fixed blade angle mode power data.

The powertrain mathematical model building submodule may include a power matching unit for:

selecting a blade angle, and calculating the required power of the propeller at each flight height and flight speed by using the selected blade angle and a propeller power coefficient characteristic curve, wherein the selected blade angle is the minimum blade angle or the maximum blade angle, and the propeller power coefficient characteristic curve represents the relation between the propeller power coefficient and the propeller advancing distance ratio at different blade angles;

and performing power matching by using the calculated propeller required power and an engine power characteristic curve to obtain the engine matching rotating speed and the engine matching power of different throttle lever positions at various flight heights and flight speeds, wherein the engine power characteristic curve represents the relation between the engine output power and the engine rotating speed at different throttle lever positions.

The performance curve of the engine comprises a power characteristic curve of the engine, the performance curve of the propeller comprises a power coefficient characteristic curve of the propeller, a tension coefficient characteristic curve of the propeller and an efficiency characteristic curve of the propeller, and the tension coefficient characteristic curve of the propeller represents the relationship between the tension coefficient of the propeller and the advance ratio of the propeller under different blade angles; the propeller efficiency characteristic curve represents the relationship between the propeller efficiency and the propeller pitch ratio under different blade angles.

The powertrain mathematical model building submodule may include a computing unit configured to:

Fig. 10 is a hardware configuration diagram of a propeller blade angle adjustment apparatus according to a sixth embodiment of the present invention.

The propeller blade angle adjusting device of the sixth embodiment of the invention mainly comprises a CPLD, an isolation power supply module, a power supply filter circuit, an extended memory, an isolation RS422, a motor driver, a current acquisition circuit and a rotating speed acquisition circuit. The CPLD is a core processor, an EPM2210GF256I chip can be adopted, the chip is provided with 2210 logic units, and control strategies, algorithms and interface protocols are realized by adopting logic languages, so that the stability of the propeller blade angle adjusting device can be ensured. The motor driver BTM7752G chip is a direct current motor driving chip, comprises a full bridge and bridge arm driving control circuit, a protection monitoring circuit based on current and voltage sampling and a state feedback circuit, and has perfect fault monitoring and protecting functions. The rotating speed acquisition circuit can be used for isolating and acquiring the rotating speed of the engine by a PS2805 optical coupler. The RS422 interface adopts an ADM2682EBRIZ chip which is an isolated RS422 chip, integrates 15KV ESD protection, can communicate with a flight control computer, is used for receiving configuration commands and feeding back blade state information, and has the highest data rate of 16 Mbps. The extended memory adopts an FM22L16 chip which is a 4Mbit ferroelectric memory and has the function of keeping data after power failure. The isolation power supply module adopts an isolation power supply with an overcurrent and overvoltage protection function. The power supply filter circuit adopts a special anti-surge chip and a power supply filter module, and meets the power supply requirement of airborne equipment. It should be noted that the chip described above in the embodiment of the present invention may be replaced by another chip having the same function.

The CPLD can implement the corresponding function of the core processing module 903, the RS422 interface can implement the corresponding function of the communication module 901, and the rotational speed acquisition circuit can implement the corresponding function of the rotational speed acquisition module 902. The hardware module or the circuit is combined with the blade angle operation model building module, and comprises functional modules, submodules and units such as a power system mathematical model building submodule (comprising a power matching unit and a calculating unit) and the like, so that the propeller blade angle adjusting device provided by the embodiment of the invention is realized. The functions of the modules are described in detail in the above embodiments, and are not repeated here.

The propeller blade angle adjusting device has the specific constant-speed variable pitch function and is divided into take-off, climbing and cruising modes in different flight stages; and the propeller blade angle value can be obtained through a blade angle value function fitted by a least square method under the condition of no blade angle position sensor according to the flight speed and speed of the unmanned aerial vehicle and the throttle lever position of the engine.

In addition, the specific implementation contents of the propeller blade angle adjustment device in the embodiment of the present invention have been described in detail in the above propeller blade angle adjustment method, and therefore, the repeated contents will not be described again.

FIG. 11 illustrates an exemplary system architecture 1100 to which the propeller blade angle adjustment method or propeller blade angle adjustment apparatus of embodiments of the present invention may be applied.

As shown in fig. 11, the system architecture 1100 may include

terminal devices

1101, 1102, 1103, a network 1104, and a server 1105. The network 1104 is a medium to provide communication links between the

terminal devices

1101, 1102, 1103 and the server 1105. Network 1104 may include various connection types, such as wired, wireless communication links, or fiber optic cables, to name a few.

A user may use

terminal devices

1101, 1102, 1103 to interact with a server 1105 over a network 1104 to receive or send messages or the like. Various communication client applications, such as a web browser application or the like (for example only), may be installed on the

terminal devices

1101, 1102, 1103.

The

terminal devices

1101, 1102, 1103 may be various electronic devices having a display screen and supporting web browsing, including but not limited to smart phones, tablet computers, laptop portable computers, desktop computers, and the like

The server 1105 may be a server that provides various services, such as a backend management server (for example only) that provides support for websites browsed by users using the

terminal devices

1101, 1102, 1103. The backend management server may analyze and otherwise process data such as the received product information query request, and feed back a processing result (e.g., pushed information — just an example) to the terminal device.

It should be noted that the method for adjusting the angle of the propeller blades provided by the embodiment of the present invention is generally executed by the server 1105, and accordingly, the device for adjusting the angle of the propeller blades is generally disposed in the server 1105.

It should be understood that the number of terminal devices, networks, and servers in fig. 11 is merely illustrative. There may be any number of terminal devices, networks, and servers, as desired for implementation.

Referring now to FIG. 12, shown is a block diagram of a computer system 1200 suitable for use in implementing a terminal device or server of an embodiment of the present application. The terminal device or the server shown in fig. 12 is only an example, and should not bring any limitation to the functions and the scope of use of the embodiments of the present application.

As shown in fig. 12, the computer system 1200 includes a Central Processing Unit (CPU)1201, which can perform various appropriate actions and processes in accordance with a program stored in a Read Only Memory (ROM)1202 or a program loaded from a storage section 1208 into a Random Access Memory (RAM) 1203. In the RAM 1203, various programs and data necessary for the operation of the system 1200 are also stored. The CPU 1201, ROM 1202, and RAM 1203 are connected to each other by a bus 1204. An input/output (I/O) interface 1205 is also connected to bus 1204.

The following components are connected to the I/O interface 1205: an input section 1206 including a keyboard, a mouse, and the like; an output portion 1207 including a display device such as a Cathode Ray Tube (CRT), a Liquid Crystal Display (LCD), and the like, and a speaker; a storage section 1208 including a hard disk and the like; and a communication section 1209 including a network interface card such as a LAN card, a modem, or the like. The communication section 1209 performs communication processing via a network such as the internet. A driver 1210 is also connected to the I/O interface 1205 as needed. A removable medium 1211, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, or the like, is mounted on the drive 1210 as necessary, so that a computer program read out therefrom is mounted into the storage section 1208 as necessary.

In particular, according to the embodiments of the present disclosure, the processes described above with reference to the flowcharts may be implemented as computer software programs. For example, embodiments of the present disclosure include a computer program product comprising a computer program embodied on a computer readable medium, the computer program comprising program code for performing the method illustrated in the flow chart. In such an embodiment, the computer program may be downloaded and installed from a network through the communication section 1209, and/or installed from the removable medium 1211. The computer program performs the above-described functions defined in the system of the present application when executed by the Central Processing Unit (CPU) 1201.

It should be noted that the computer readable medium shown in the present invention can be a computer readable signal medium or a computer readable storage medium or any combination of the two. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the foregoing. More specific examples of the computer readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the present application, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. In this application, however, a computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated data signal may take many forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may also be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wire, fiber optic cable, RF, etc., or any suitable combination of the foregoing.

The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams or flowchart illustration, and combinations of blocks in the block diagrams or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

The modules described in the embodiments of the present invention may be implemented by software or hardware. The described modules may also be provided in a processor, which may be described as: a processor comprises a communication module, a rotating speed acquisition module and a core processing module. The names of these modules do not in some cases constitute a limitation on the module itself, and for example, the communication module may also be described as a "module for receiving a switching instruction of an airplane mode".

As another aspect, the present invention also provides a computer-readable medium that may be contained in the apparatus described in the above embodiments; or may be separate and not incorporated into the device. The computer readable medium carries one or more programs which, when executed by a device, cause the device to comprise: receiving a switching instruction of a flight mode, and acquiring the rotating speed of an engine in real time, wherein the switching instruction indicates that the current flight mode is switched to a target flight mode; gradually adjusting the blade angle of the propeller under the condition that the collected rotating speed of the engine exceeds the set rotating speed range of the target flight mode; and when the rotating speed of the engine is within the set rotating speed range by adjusting the position of a blade angle, stopping adjusting the blade angle, and calculating to obtain a real-time blade angle value through a blade angle operation model corresponding to the target flight mode.

According to the technical scheme of the embodiment of the invention, the rotating speed of the engine is collected in real time, and the blade angle of the propeller is gradually adjusted under the condition that the collected rotating speed of the engine exceeds the set rotating speed range of the target flight mode; and when the blade angle position is adjusted to enable the rotating speed of the engine to be within the set rotating speed range, stopping adjusting the blade angle. Can realize the paddle angle modulation of unmanned aerial vehicle flight in-process. And inputting the information of the flight height, the flight speed, the throttle lever position and the engine rotating speed of the airplane obtained in real time into a blade angle operation model corresponding to the target flight mode so as to calculate the real-time blade angle value. Therefore, the blade angle value of the propeller can be obtained under the condition of no blade angle position sensor.

The above-described embodiments should not be construed as limiting the scope of the invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions can occur, depending on design requirements and other factors. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method of adjusting the angle of a propeller blade, comprising:

receiving a switching instruction of a flight mode, and acquiring the rotating speed of an engine in real time, wherein the switching instruction indicates that the current flight mode is switched to a target flight mode;

gradually adjusting the blade angle of the propeller under the condition that the collected rotating speed of the engine exceeds the set rotating speed range of the target flight mode;

and when the rotating speed of the engine is within the set rotating speed range by adjusting the position of a blade angle, stopping adjusting the blade angle, and calculating to obtain a real-time blade angle value through a blade angle operation model corresponding to the target flight mode.

2. The method of claim 1, wherein the step of calculating a real-time blade angle value using a blade angle calculation model corresponding to the target flight mode comprises:

and inputting the information of the flight height, the flight speed, the throttle lever position and the engine rotating speed of the airplane obtained in real time into a blade angle operation model corresponding to the target flight mode so as to calculate and obtain the real-time blade angle value.

3. The method of claim 2, wherein the operational model of blade angle corresponding to a flight mode is obtained by:

establishing a power system mathematical model under the flight mode by utilizing the matching relation between the propeller required power and the engine output power, wherein the power system mathematical model comprises a plurality of groups of discrete value sets corresponding to the flight mode, and each group of discrete value sets comprises discrete values of flight height, flight speed, throttle lever position, engine rotating speed and blade angle;

4. The method of claim 3, wherein the step of using the match between the power demand from the propeller and the power output from the engine to create a mathematical model of the powertrain in flight mode comprises:

setting the constant rotating speed of the engine in the flight mode;

calculating first fixed blade angle mode power data corresponding to the minimum blade angle, wherein the first fixed blade angle mode power data comprise: the minimum blade angle and the corresponding aircraft flying height, flying speed, throttle lever position and first matching rotating speed of the engine; the first matching rotating speed of the engine is obtained by matching propeller required power with engine output power under the condition of minimum blade angle and is less than or equal to the constant rotating speed of the engine;

calculating constant speed mode power data, the constant speed mode power data comprising: a first blade angle of the propeller and the corresponding flying height, flying speed, throttle lever position and constant rotating speed of the engine of the airplane; the first propeller blade angle is a propeller blade angle which is calculated by utilizing the constant rotating speed of the engine, the flying height, the position of the throttle lever, an engine performance curve and a propeller performance curve and is less than or equal to the maximum blade angle, and the engine performance curve represents the relation between engine performance parameters; the propeller performance curves represent relationships between propeller performance parameters;

calculating second fixed blade angle mode dynamic data corresponding to the maximum blade angle, wherein the second fixed blade angle mode dynamic data comprises: the maximum blade angle and the corresponding aircraft flying height, flying speed, throttle lever position and second matching rotating speed of the engine; the second matching rotating speed of the engine is obtained by matching the required power of the propeller with the output power of the engine under the condition of the maximum blade angle;

5. The method of claim 4, wherein the step of obtaining the engine matched speed by matching a propeller demand power to an engine output power comprises:

6. The method of claim 5, wherein the engine performance curve comprises the engine power characteristic curve, a propeller performance curve comprises the propeller power coefficient characteristic curve, a propeller coefficient of tension characteristic curve, a propeller efficiency characteristic curve, and the propeller coefficient of tension characteristic curve represents a relationship between a propeller coefficient of tension and a propeller pitch ratio at different blade angles; the propeller efficiency characteristic curve represents the relationship between the propeller efficiency and the propeller pitch ratio under different blade angles;

calculating the first blade angle of the propeller by:

calculating the output power of the engine under the constant rotating speed of the engine according to the flying heights, the positions of different throttle levers, the constant rotating speed of the engine and the power characteristic curve of the engine;

and calculating the advancing distance ratio, the power coefficient, the tension coefficient, the efficiency, the tension and the first blade angle of the propeller by utilizing the constant rotating speed of the engine and the corresponding output power of the engine, the flying height and the flying speed, the power coefficient characteristic curve of the propeller, the tension coefficient characteristic curve of the propeller and the efficiency characteristic curve of the propeller.

7. The method of claim 2, wherein said switching command of flight mode is received from a flight control computer through a serial communication interface and the flight altitude, flight speed, throttle lever position information of said aircraft are obtained in real time, and said calculated real-time blade angle value is fed back to said flight control computer for display.

8. A propeller blade angle adjustment device, comprising:

the communication module is used for receiving a switching instruction of a flight mode, wherein the switching instruction indicates that the current flight mode is switched to a target flight mode;

the rotating speed acquisition module is used for acquiring the rotating speed of the engine in real time;

the core processing module is used for sending an adjusting instruction to the propeller to gradually adjust the blade angle of the propeller under the condition that the rotating speed of the engine acquired by the rotating speed acquisition module exceeds the set rotating speed range of the target flight mode; and when the rotating speed of the engine is within the set rotating speed range by adjusting the position of a blade angle, stopping adjusting the blade angle, and calculating to obtain a real-time blade angle value through a blade angle operation model corresponding to the target flight mode.

9. The apparatus of claim 8, wherein the core processing module is further configured to:

10. The apparatus of claim 9, further comprising a blade angle calculation model building module configured to:

obtaining a blade angle operation model corresponding to a flight mode by the following method:

11. The apparatus of claim 10, wherein the blade angle operational model building module comprises a power system mathematical model building submodule for:

setting the constant rotating speed of the engine in the flight mode;

12. The apparatus of claim 11 wherein the powertrain system mathematical model building submodule includes a power matching unit configured to:

13. The apparatus of claim 12 wherein said engine performance curve comprises said engine power characteristic curve and a propeller performance curve comprises said propeller power coefficient characteristic curve, a propeller coefficient of tension characteristic curve, a propeller efficiency characteristic curve, said propeller coefficient of tension characteristic curve representing a relationship between a propeller coefficient of tension and a propeller pitch ratio at different blade angles; the propeller efficiency characteristic curve represents the relationship between the propeller efficiency and the propeller pitch ratio under different blade angles;

the power system mathematical model construction submodule comprises a calculation unit, and is used for:

14. An electronic device, comprising:

one or more processors;

a memory for storing one or more programs,

the one or more programs, when executed by the one or more processors, cause the one or more processors to implement the method recited in any of claims 1-7.

15. A computer-readable medium, on which a computer program is stored, which, when being executed by a processor, carries out the method according to any one of claims 1-7.