阅读说明：本技术 一种共轴对转螺旋桨推进系统控制方法 (Control method of coaxial contra-rotating propeller propulsion system ) 是由 杨骁� 王向阳 朱纪洪 袁夏明 和阳 于 2019-09-06 设计创作，主要内容包括：本专利通过对对转螺旋桨系统效率离线优化数据库的构建和优化,并在此基础上结合在线优化算法实时解算出使得对转螺旋桨推进系统综合效率最优的转速和标称桨距角,最后由转速闭环控制微调桨距角以满足实际飞行工况。该专利在保证对转螺旋桨推进系统总体效率最优的基础上,提高了实时性,更容易提升对转螺旋桨推进系统控制的实时性。(According to the method, the efficiency offline optimization database of the contra-rotating propeller system is constructed and optimized, the rotating speed and the nominal pitch angle which enable the comprehensive efficiency of the contra-rotating propeller propulsion system to be optimal are calculated in real time by combining an online optimization algorithm on the basis, and finally the pitch angle is finely adjusted by closed-loop control of the rotating speed so as to meet the actual flight working condition. On the basis of ensuring the optimal overall efficiency of the contra-rotating propeller propulsion system, the control method improves the real-time performance and improves the control real-time performance of the contra-rotating propeller propulsion system more easily.)

1. A method of controlling a coaxial contra-rotating propeller propulsion system, comprising:

by utilizing numerical simulation calculation and ground test results, an offline database 1 of the forward ratio, the front pitch angle and the back pitch angle of the rotating efficiency and the thrust is constructed;

using the test data, an off-line database 2 of engine efficiency with respect to torque and rotational speed is constructed;

storing the offline database 1 and the offline database 2 in an airborne control system of the aircraft;

according to the current aircraft state parameters, the aircraft dynamics model is used for solving the balancing at the current speed to solve the current propulsion system tension requirement;

according to the current flight speed and the pulling force requirement of the propulsion system, an offline database 1 and an offline database 2, online routing optimization is carried out by adopting a neural network optimization algorithm, the online routing optimization process is stopped when the product of the maximum engine efficiency and the propeller efficiency in all iterations is obtained, the rotating speed of an engine is output as the output value of the propulsion system, and the calculated front propeller pitch angle and the calculated back propeller pitch angle are used as the nominal values for controlling the propulsion system;

and finally, calculating the propeller pitch angle increment through closed-loop feedback of the flight speed of the aircraft, adding the propeller pitch angle increment and the nominal values of the front pitch angle and the back pitch angle, and outputting the added value as a propeller pitch angle output instruction value.

2. Method according to claim 1, characterized in that optimal front and back pitch angles for different forward ratios are solved based on an optimization algorithm and an offline database 1, resulting in a dimensionality reduction database 3;

storing the off-line database 2 and the off-line database 3 in an onboard control system of the aircraft;

according to the current flight speed and the pulling force requirement of the propulsion system, an offline database 3 and an offline database 4, online routing optimization is carried out by adopting a neural network optimization algorithm, the online routing optimization process is stopped when the product of the maximum engine efficiency and the propeller efficiency in all iterations is obtained, the rotating speed of an engine is output as the output value of the propulsion system, and the calculated front propeller pitch angle and the calculated back propeller pitch angle are used as the nominal values for controlling the propulsion system;

and finally, calculating the propeller pitch angle increment through closed-loop feedback of the flight speed of the aircraft, adding the propeller pitch angle increment and the nominal values of the front pitch angle and the back pitch angle, and outputting the added value as a propeller pitch angle output instruction value.

Technical Field

The invention belongs to the field of propeller control, and particularly relates to a control method of a coaxial contra-rotating propeller propulsion system.

Background

The coaxial contra-rotating propeller propulsion system mainly comprises two coaxial contra-rotating propellers and an engine system, wherein the total distance of the propellers can be independently controlled. The mechanism of mutual influence and the coupling rule of the front blade and the rear blade of the coaxial contra-rotating propeller are very complex, the matching of the blade pitches of the front blade and the rear blade not only influences the pneumatic efficiency of a propeller system and the fuel efficiency of an engine, but also causes blade fatigue due to periodic pneumatic load among the blades, and the result of blade fracture may be caused by long-term flight. The accuracy and real-time requirements imposed on the pitch matching and control system of the two blades are therefore very strict. At present, the online optimization control method suitable for the traditional propeller propulsion system has a very limited prospect for being applied to the control of the coaxial contra-rotating propeller propulsion system because the calculated amount is large and the real-time performance is difficult to ensure.

According to the method, the efficiency offline optimization database of the contra-rotating propeller system is constructed and optimized, the rotating speed and the nominal pitch angle which enable the comprehensive efficiency of the contra-rotating propeller propulsion system to be optimal are calculated in real time by combining an online optimization algorithm on the basis, and finally the pitch angle is finely adjusted by closed-loop control of the rotating speed so as to meet the actual flight working condition. On the basis of ensuring the optimal overall efficiency of the contra-rotating propeller propulsion system, the control method improves the real-time performance and improves the control real-time performance of the contra-rotating propeller propulsion system more easily.

Disclosure of Invention

The purpose of the invention is as follows: in order to solve the problem that the real-time performance of a control system is difficult to ensure while the comprehensive efficiency of a propeller and an engine in a coaxial contra-rotating propeller propulsion system is optimally controlled, a control method of the coaxial contra-rotating propeller propulsion system based on the combination of an offline optimization database and online real-time efficiency optimization is provided.

The technical scheme is as follows:

on the first hand, an offline database 1 of the forward ratio, the front pitch angle and the back pitch angle of the rotating efficiency and the thrust is constructed by numerical simulation calculation or by adopting a ground test result; using the test data, an off-line database 2 of engine efficiency with respect to torque and rotational speed is constructed; storing the offline database 1 and the offline database 2 in an airborne control system of the aircraft;

the method is used for online search, the method for constructing the database combines CFD calculation and ground test, the relation between the front pitch angle and the back pitch angle which enables the optimal propeller efficiency is solved under different propulsion ratios, and the offline database of the propeller efficiency and the thrust relative to the advancing ratio, the front pitch angle and the back pitch angle is stored in a controller;

in a second aspect, a crp pitch angle control method based on online optimization of the overall efficiency of a crp propulsion system is provided:

according to the current state of the propulsion system and state parameters thereof, wherein the state parameters comprise flight speed and flight height information; according to the current flight speed and the pulling force requirement of the propulsion system, an offline database 3 and an offline database 4, online routing optimization is carried out by adopting a neural network optimization algorithm, the online routing optimization process is stopped when the product of the maximum engine efficiency and the propeller efficiency in all iterations is obtained, the rotating speed of an engine is output as the output value of the propulsion system, and the calculated front propeller pitch angle and the calculated back propeller pitch angle are used as the nominal values for controlling the propulsion system;

and finally, calculating the propeller pitch angle increment through closed-loop feedback of the flight speed of the aircraft, adding the propeller pitch angle increment and the nominal values of the front pitch angle and the back pitch angle, and outputting the added value as a propeller pitch angle output instruction value.

Advantageous technical effects

The method has the advantages of accurate algorithm, high real-time performance, high engineering practical value and the like, can be used for the online optimization control problem of the propulsion system of the high-speed helicopter, and solves the reliability and the working efficiency of the contra-rotating propeller and the engine in the full-flight envelope.

Detailed description of the preferred embodiments

The technical scheme is as follows:

(1) constructing an offline database 1 of efficiency and thrust versus advancing ratio, forward pitch angle and aft pitch angle for rotor

The numerical simulation calculation is used, and the ground test result can also be adopted to construct an offline database 1 of the forward ratio, the front pitch angle and the back pitch angle of the rotating efficiency and the thrust; using the test data, an off-line database 2 of engine efficiency with respect to torque and rotational speed is constructed; storing the offline database 1 and the offline database 2 in an airborne control system of the aircraft;

(2) defining a relationship between a forward pitch angle and a back pitch angle that optimizes efficiency of feathering for different propulsion ratios

The method is used for online search, the method for constructing the database combines CFD calculation and ground test, the relation between the front pitch angle and the back pitch angle which enables the optimal propeller efficiency is solved under different propulsion ratios, and the offline database of the propeller efficiency and the thrust relative to the advancing ratio, the front pitch angle and the back pitch angle is stored in a controller;

(3) calculating the front and back pitch angles of the propeller as the nominal values for the propulsion system control

According to the current state of the propulsion system and state parameters thereof, wherein the state parameters comprise flight speed and flight height information; according to the current flight speed and the pulling force requirement of the propulsion system, an offline database 3 and an offline database 4, online routing optimization is carried out by adopting a neural network optimization algorithm, the online routing optimization process is stopped when the product of the maximum engine efficiency and the propeller efficiency in all iterations is obtained, the rotating speed of an engine is output as the output value of the propulsion system, and the calculated front propeller pitch angle and the calculated back propeller pitch angle are used as the nominal values for controlling the propulsion system;

(4) propeller pitch angle adjustment increment for resolving closed-loop feedback of flight speed of aircraft

And calculating the propeller pitch angle increment through closed-loop feedback of the flight speed of the aircraft, adding the propeller pitch angle increment and the nominal values of the front pitch angle and the back pitch angle, and outputting the added value as a propeller pitch angle output instruction value.