Feed-forward control law design method and system based on large-cavity effect model

Abstract

The invention relates to the technical field of aero-engine air inlet condition simulation control, and discloses a feed-forward control law design method and a feed-forward control law design system based on a large-cavity effect model. A dynamic disturbance model with a pressure disturbance amplitude and a pressure regulation time as coordinate values is established, and real data is used for comparison and check, so that the pressure disturbance amplitude and the pressure regulation time are calculated; forming an optimized dynamic disturbance model; and finally, a feed-forward control law based on transition state flow dynamic characteristics and air inlet total pressure change differential is constructed through valve adjusting characteristics, and the feed-forward control quantity of each air inlet branch is calculated in real time. According to the invention, while the pressure disturbance rejection capability of the air inlet control system of the test equipment in the dynamic response test is improved, the multi-branch feedforward control quantity can be calculated and output in the actual transition state test; the method is beneficial for improving the transition state control quality of the test equipment air inlet control system on the total air inlet pressure in the engine transition state test, reducing the deviation value of the disturbance of the total pressure, and improving the simulation precision of the total air inlet pressure in the transition state test.

Description

Technical Field

[0001] The invention relates to the technical field of simulated control of intake conditions of aircraft engines, and discloses a feedforward control law design method and system based on a large cavity effect model. Background Art

[0002] When simulating the intake and exhaust conditions of an aircraft engine in flight in the test equipment and testing the engine's key performance functions, the large-scale civil power test bench has the significant characteristics of complex structure, large main air cavity volume, obvious transition flow filling lag effect, and long pressure hysteresis response time, which is not conducive to transition state testing, especially the intake and exhaust pressure regulation during the 1-second dynamic response test process.

[0003] Although the current linear active disturbance rejection control technology has greatly improved the environmental disturbance rejection adjustment capability of transient state tests, there is still a significant lag in the controlled pressure response, especially in low-altitude and low-indicated-speed tests. Therefore, it is necessary to use active disturbance rejection control combined with a feedforward control method to suppress disturbances in strong transient tests.

[0004] Feedforward control mainly depends on the process characteristics of the controlled object. The feedforward law of each feedforward controller is basically dedicated, and the corresponding design methods are also different. Due to the strong versatility of test equipment, the process characteristics of the test object, such as the transient flow range and change rate, are different, and the characteristics such as the disturbance amplitude generated on the intake and exhaust chamber pressure are also inconsistent. Therefore, the required feedforward control law cannot be a single trend, but a number of complex surfaces. Most existing patents are aimed at relatively fixed process characteristics of the controlled object, obtain the difference between the starting point and the end point of the disturbance process, and calculate the specific feedforward compensation amount based on a specific model. This method is only applicable to the process control of dedicated objects and cannot meet the versatility requirements of test equipment. Summary of the Invention

[0005] The purpose of the present invention is to provide a feedforward control law design method and system based on a large cavity effect model, which can improve the pressure disturbance resistance of the test equipment intake control system in the dynamic response test, and improve the transition state control quality of the test equipment intake control system on the total intake pressure in the engine transition state test, reduce the deviation value of the total pressure disturbance, and improve the simulation accuracy of the transition state test total intake pressure.

[0006] In order to achieve the above technical effects, the technical solution adopted by the present invention is: A feedforward control law design method based on a large cavity effect model includes: Step 1: Construct a simulation model of an air intake chamber for aircraft engine testing. The air intake chamber is used to provide an air environment for aircraft engine testing. The air intake chamber is provided with an exhaust branch and multiple air intake branches, and each of the air intake branches is provided with a control valve for controlling air flow; Step 2: Using the total intake temperature, total intake pressure, starting flow rate, end flow rate, and process flow rate change time of multiple typical transient operating points of the aircraft engine as input, the simulation model is used for simulation analysis to obtain a pressure change curve of the intake chamber at each transient operating point; the typical transient operating points include operating points where the throttle lever changes from slow to maximum state within a preset time under different flight altitude conditions; Step 3: Extracting the pressure disturbance amplitude and pressure adjustment time of the intake chamber based on the pressure change curve at each transient operating point; the pressure adjustment time is the time it takes for the initial value of the chamber pressure before the engine state changes to deviate due to the transient state effect and then return to the initial value under the corresponding transient operating point; Step 4: Based on the pressure disturbance amplitude and pressure adjustment time of the intake cavity at each transition state operating point, as well as the total air flow rate, intake cavity pressure, and intake total temperature of the intake cavity at the corresponding transition state operating point, a dynamic disturbance model is constructed with the total air flow rate, intake cavity pressure, and intake total temperature of the intake cavity as coordinate axes and the pressure disturbance amplitude and pressure adjustment time as coordinate values; Step 5: Experimentally obtain actual values of the pressure disturbance amplitude and the pressure adjustment time of the aircraft engine at a transient state test point, and input the total air flow rate, total intake air temperature, and intake chamber pressure data collected during the transient state test of the aircraft engine into the dynamic disturbance model to analyze and obtain simulated values of the pressure disturbance amplitude and the pressure adjustment time of the aircraft engine at the corresponding transient state; Step 6: quantify the nonlinear dynamic errors between the pressure disturbance amplitude simulation value and the pressure adjustment time simulation value output by the dynamic disturbance model and the corresponding measured values by using a dynamic weighted integral error analysis method to obtain a normalized weighted integral error index; taking the normalized weighted integral error index as not greater than a first preset threshold and the error between the intake chamber pressure simulation value and the measured value as not greater than a second preset threshold as optimization goals, use a single-objective gradient descent optimization method to iteratively update the learning parameters in the negative gradient direction to optimize the dynamic disturbance model, and obtain an optimized dynamic disturbance model; Step seven: According to the current deviation value of the intake chamber pressure, a feedforward control law for the intake chamber based on the feedforward compensation amount of each intake branch is established, and the intake chamber pressure differential is obtained according to the optimized dynamic disturbance model analysis. The integral and deviation of the intake chamber pressure differential in each PLC controller calculation cycle are used as input, and the feedforward compensation amount of each intake branch is calculated through the feedforward control law of the intake chamber to obtain the feedforward compensation amount of each intake branch that meets the total air flow compensation of the intake chamber during the transient state test of the aircraft engine.

[0007] Furthermore, the normalized weighted integral error index in step 6 is ,in is the simulated value of the pressure disturbance amplitude output by the dynamic disturbance model at time t, is the total intake pressure collected at time t, is the starting time of the transition state, is the end time of the transition state, is the time constant of the exponential decay weight, The value range is 0.1 to 3.

[0008] Furthermore, in step 7, the feedforward control law of the intake chamber based on the feedforward compensation of each intake branch is established as ,in For the The feedforward compensation of each branch is: is the current deviation value of the intake chamber pressure, is the differential deviation of the current intake chamber pressure, For the The proportional gain of the intake branch, The value range is 1.2~2.4, For the The differential gain of the intake branch, The value range is 0.2 to 0.6.

[0009] Furthermore, in step seven, the pressure differential of the intake chamber is , is the differential pressure of the intake chamber, V is the volume of the intake cavity, is the specific heat of air, R is the gas constant, For the The air flow of the intake branch, is the intake air flow of the engine.

[0010] To achieve the above technical effects, the present invention further provides a feedforward control law design system based on a large cavity effect model, which is used to implement the feedforward control law design method based on a large cavity effect model, comprising: A simulation model construction module is used to construct a simulation model of an intake chamber for aircraft engine testing, wherein the intake chamber is used to provide an air environment for aircraft engine testing, the intake chamber is provided with an exhaust branch and multiple intake branches, and each of the intake branches is provided with a control valve for controlling air flow; a simulation analysis module for using the simulation model to analyze and obtain a pressure variation curve of the intake chamber at each transition state operating point using the total intake temperature, total intake pressure, starting flow rate, end flow rate, and process flow rate variation time at multiple typical transition state operating points of the aircraft engine; the typical transition state operating points include operating points where the throttle lever changes from an idle state to a maximum state within a preset time at different flight altitudes; a data acquisition module for extracting the pressure disturbance amplitude and pressure adjustment time of the intake chamber based on the pressure change curve at each transient operating point; the pressure adjustment time being the time it takes for the initial value of the chamber pressure to deviate from the initial value due to the transient state influence before the engine state changes under the corresponding transient operating point to return to the initial value; a disturbance model construction module for constructing a dynamic disturbance model with the total air flow rate of the intake chamber, the intake chamber pressure, and the total intake air temperature as coordinate axes and the pressure disturbance amplitude and the pressure adjustment time as coordinate values, based on the pressure disturbance amplitude and the pressure adjustment time of the intake chamber at each transient operating point, as well as the total air flow rate of the intake chamber, the intake chamber pressure, and the total intake air temperature at the corresponding transient operating point; a data analysis module for inputting, based on the actual measured values of the pressure disturbance amplitude and the actual measured values of the pressure adjustment time of the aircraft engine at the transient state test point obtained in the test, the total air flow rate, the total intake air temperature, and the intake chamber pressure data collected during the transient state test of the aircraft engine into the dynamic disturbance model, and analyzing to obtain simulated values of the pressure disturbance amplitude and the pressure adjustment time of the aircraft engine at the corresponding transient state; a model optimization module for quantifying the nonlinear dynamic errors between the pressure disturbance amplitude simulation value and the pressure adjustment time simulation value output by the dynamic disturbance model and the corresponding measured values by using a dynamic weighted integral error analysis method to obtain a normalized weighted integral error index; taking the normalized weighted integral error index as not greater than a first preset threshold and the error between the intake chamber pressure simulation value and the measured value as not greater than a second preset threshold as optimization objectives, and using a single-objective gradient descent optimization method to iteratively update the learning parameters in the negative gradient direction to optimize the dynamic disturbance model, thereby obtaining an optimized dynamic disturbance model; The compensation analysis module is used to establish a feedforward control law for the intake chamber based on the feedforward compensation of each intake branch according to the current deviation value of the intake chamber pressure, and obtain the intake chamber pressure differential according to the optimized dynamic disturbance model analysis. The integral and deviation of the intake chamber pressure differential in each PLC controller calculation cycle are used as input, and the feedforward compensation of each intake branch is calculated through the feedforward control law of the intake chamber to obtain the feedforward compensation of each intake branch that meets the total air flow compensation of the intake chamber during the transient state test of the aircraft engine.

[0011] Furthermore, in the model optimization module, the normalized weighted integral error index ,in is the simulated value of the pressure disturbance amplitude output by the dynamic disturbance model at time t, is the total intake pressure collected at time t, is the starting time of the transition state, is the end time of the transition state, is the time constant of the exponential decay weight, The value range is 0.1 to 3.

[0012] Furthermore, in the compensation analysis module, the feedforward control law of the intake cavity based on the feedforward compensation of each intake branch is established as follows: ,in For the The feedforward compensation of each branch is: is the current deviation value of the intake chamber pressure, is the differential deviation of the current intake chamber pressure, For the The proportional gain of the intake branch, The value range is 1.2~2.4, For the The differential gain of the intake branch, The value range is 0.2 to 0.6.

[0013] Furthermore, in the compensation analysis module, the intake chamber pressure differential , is the differential pressure of the intake chamber, V is the volume of the intake cavity, is the specific heat of air, R is the gas constant, For the The air flow of the intake branch, is the intake air flow of the engine.

[0014] Compared with the prior art, the beneficial effects of the present invention are: while improving the pressure anti-disturbance capability of the test equipment intake control system in the dynamic response test, the present invention can calculate and output the multi-branch feedforward control quantity in the actual transition state test, which helps to improve the transition state control quality of the test equipment intake control system on the total intake pressure in the engine transition state test, reduce the deviation value of the total pressure caused by disturbance, and improve the simulation accuracy of the total intake pressure in the transition state test. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a flow chart of the feedforward control law design method based on the large cavity effect model in Example 1 or 2; Figure 2 This is a structural block diagram of the feedforward control law design system based on the large cavity effect model in Example 1; Figure 3 This is a schematic diagram of the specific structure of a large-scale test equipment in Example 2; Figure 4 Schematic diagram of the dynamic disturbance model in Example 2; Figure 5 This is a schematic diagram of the real-time settlement framework of the feedforward control quantity during the test process in Example 2; Among them, 1. Simulation model construction module; 2. Simulation analysis module; 3. Data acquisition module; 4. Perturbation model construction module; 5. Data analysis module; 6. Model optimization module; 7. Compensation analysis module. DETAILED DESCRIPTION

[0016] The present invention will be described in further detail below with reference to the embodiments and accompanying drawings. However, this should not be construed as limiting the scope of the present invention to the following embodiments, as all technologies implemented based on the present invention fall within the scope of the present invention.

[0017] Example 1 See also Figure 1 、 Figure 2 , a feedforward control law design method based on a large cavity effect model, comprising: Step 1: Construct a simulation model of an air intake chamber for aircraft engine testing. The air intake chamber is used to provide an air environment for aircraft engine testing. The air intake chamber is provided with an exhaust branch and multiple air intake branches, and each of the air intake branches is provided with a control valve for controlling air flow; Step 2: Using the total intake temperature, total intake pressure, starting flow rate, end flow rate, and process flow rate change time of multiple typical transient operating points of the aircraft engine as input, the simulation model is used for simulation analysis to obtain a pressure change curve of the intake chamber at each transient operating point; the typical transient operating points include operating points where the throttle lever changes from slow to maximum state within a preset time under different flight altitude conditions; Step 3: Extracting the pressure disturbance amplitude and pressure adjustment time of the intake chamber based on the pressure change curve at each transient operating point; the pressure adjustment time is the time it takes for the initial value of the chamber pressure before the engine state changes to deviate due to the transient state effect and then return to the initial value under the corresponding transient operating point; Step 4: Based on the pressure disturbance amplitude and pressure adjustment time of the intake cavity at each transition state operating point, as well as the total air flow rate, intake cavity pressure, and intake total temperature of the intake cavity at the corresponding transition state operating point, a dynamic disturbance model is constructed with the total air flow rate, intake cavity pressure, and intake total temperature of the intake cavity as coordinate axes and the pressure disturbance amplitude and pressure adjustment time as coordinate values; Step 5: Experimentally obtain actual values of the pressure disturbance amplitude and the pressure adjustment time of the aircraft engine at a transient state test point, and input the total air flow rate, total intake air temperature, and intake chamber pressure data collected during the transient state test of the aircraft engine into the dynamic disturbance model to analyze and obtain simulated values of the pressure disturbance amplitude and the pressure adjustment time of the aircraft engine at the corresponding transient state; Step 6: quantify the nonlinear dynamic errors between the pressure disturbance amplitude simulation value and the pressure adjustment time simulation value output by the dynamic disturbance model and the corresponding measured values by using a dynamic weighted integral error analysis method to obtain a normalized weighted integral error index; taking the normalized weighted integral error index as not greater than a first preset threshold and the error between the intake chamber pressure simulation value and the measured value as not greater than a second preset threshold as optimization goals, use a single-objective gradient descent optimization method to iteratively update the learning parameters in the negative gradient direction to optimize the dynamic disturbance model, and obtain an optimized dynamic disturbance model; Step seven: According to the current deviation value of the intake chamber pressure, a feedforward control law for the intake chamber based on the feedforward compensation amount of each intake branch is established, and the intake chamber pressure differential is obtained according to the optimized dynamic disturbance model analysis. The integral and deviation of the intake chamber pressure differential in each PLC controller calculation cycle are used as input, and the feedforward compensation amount of each intake branch is calculated through the feedforward control law of the intake chamber to obtain the feedforward compensation amount of each intake branch that meets the total air flow compensation of the intake chamber during the transient state test of the aircraft engine.

[0018] In this embodiment, based on the test bench intake cavity pressure model and the intake total temperature, intake total pressure, starting flow rate, end flow rate, and process flow rate change time of multiple typical transient operating points of the aircraft engine, the pressure disturbance amplitude and pressure adjustment time of the intake cavity at each transient operating point are obtained, thereby establishing a dynamic disturbance model with the pressure disturbance amplitude and pressure adjustment time as coordinate values; by using real data for comparison and verification, an optimized dynamic disturbance model is formed; finally, a feedforward control law based on the dynamic characteristics of the transient flow rate and the differential of the intake total pressure change is constructed through the valve adjustment characteristics, and the feedforward control quantity of each intake branch is solved in real time. While improving the pressure anti-disturbance capability of the test equipment intake control system in the dynamic response test, the feedforward control quantities of multiple branches can be calculated and output in the actual transient test, which helps to improve the transient control quality of the test equipment intake control system on the intake total pressure in the engine transient test, reduce the deviation value of the total pressure disturbance, and improve the simulation accuracy of the intake total pressure in the transient test.

[0019] Based on the same inventive concept, this embodiment further provides a feedforward control law design system based on a large cavity effect model, which is used to implement the feedforward control law design method based on a large cavity effect model, including: A simulation model construction module 1 is used to construct a simulation model of an intake chamber for aircraft engine testing. The intake chamber is used to provide an air environment for aircraft engine testing. The intake chamber is provided with an exhaust branch and multiple intake branches, and each intake branch is provided with a control valve for controlling air flow; Simulation analysis module 2 is configured to use the simulation model to analyze and obtain a pressure variation curve of the intake chamber at each transition state operating point using the intake total temperature, intake total pressure, starting flow rate, end flow rate, and process flow rate variation time at multiple typical transition state operating points of the aircraft engine; the typical transition state operating points include operating points where the throttle lever changes from idle to maximum state within a preset time at different flight altitudes; Data acquisition module 3, for extracting the pressure disturbance amplitude and pressure adjustment time of the intake chamber based on the pressure change curve at each transient operating point; the pressure adjustment time is the time it takes for the initial value of the chamber pressure before the engine state changes to deviate due to the transient state effect and then return to the initial value under the corresponding transient operating point; a disturbance model construction module 4 for constructing a dynamic disturbance model with the total air flow rate, the intake cavity pressure, and the total intake air temperature as coordinate axes and the pressure disturbance amplitude and the pressure adjustment time as coordinate values, based on the pressure disturbance amplitude and the pressure adjustment time of the intake cavity at each transient operating point, as well as the total air flow rate, the intake cavity pressure, and the total intake air temperature at the corresponding transient operating point; A data analysis module 5 is configured to analyze the actual values of the pressure disturbance amplitude and the pressure adjustment time of the aircraft engine at the transient state test point obtained in the test, and input the total air flow rate, total intake air temperature, and intake chamber pressure data collected during the transient state test of the aircraft engine into the dynamic disturbance model to obtain simulated values of the pressure disturbance amplitude and the pressure adjustment time of the aircraft engine at the corresponding transient state; a model optimization module 6 for quantifying the nonlinear dynamic errors between the simulated pressure disturbance amplitude value and the simulated pressure adjustment time value output by the dynamic disturbance model and the corresponding measured values by using a dynamic weighted integral error analysis method to obtain a normalized weighted integral error index; taking the normalized weighted integral error index as no greater than a first preset threshold value and the error between the simulated intake chamber pressure value and the measured value as no greater than a second preset threshold value as optimization objectives, and using a single-objective gradient descent optimization method to iteratively update the learning parameters in the negative gradient direction to optimize the dynamic disturbance model, thereby obtaining an optimized dynamic disturbance model; The compensation analysis module 7 is used to establish a feedforward control law for the intake chamber based on the feedforward compensation of each intake branch according to the current deviation value of the intake chamber pressure, and obtain the intake chamber pressure differential according to the optimized dynamic disturbance model analysis. The integral and deviation of the intake chamber pressure differential in each PLC controller calculation cycle are used as input, and the feedforward compensation of each intake branch is calculated through the feedforward control law of the intake chamber to obtain the feedforward compensation of each intake branch that meets the total air flow compensation of the intake chamber during the transient state test of the aircraft engine.

[0020] Example 2 See also Figure 1 、 Figure 3 、 Figure 4 and Figure 5 , a feedforward control law design method based on a large cavity effect model, comprising: Step 1: Construct a simulation model of an air intake chamber for aircraft engine testing. The air intake chamber is used to provide an air environment for aircraft engine testing. The air intake chamber is provided with an exhaust branch and multiple air intake branches, and each of the air intake branches is provided with a control valve for controlling air flow; In this embodiment, Figure 3As shown in the figure, based on the specific structure of a large-scale test equipment, a pressure model of multiple inflow branches, intake chambers, and outflow branches is constructed, with key conditions such as air flow rate, total intake temperature, and pressure before the regulating valve as inputs. Each intake branch is equipped with a control valve to control air flow. P1, W1, and T1 represent the intake pressure, flow rate, and temperature of one intake branch, while P2, W2, and T2 represent the intake pressure, flow rate, and temperature of another intake branch. V, T, and P represent the volume, temperature, and pressure of the intake chamber, respectively. Wengine represents the exhaust flow rate.

[0021] Step 2: Taking the total intake temperature, total intake pressure, starting flow rate, end flow rate and process flow rate change time of multiple typical transition operating points of the aircraft engine as input, the simulation model is used for simulation analysis to obtain the pressure change curve of the intake cavity at each transition operating point; the typical transition operating point includes the operating point where the throttle lever changes from slow speed to maximum state within a preset time (such as 1 second) under different flight altitude conditions.

[0022] Step 3: Extracting the pressure disturbance amplitude and pressure adjustment time of the intake chamber based on the pressure change curve at each transient operating point; the pressure adjustment time is the time it takes for the initial value of the chamber pressure before the engine state changes to deviate due to the transient state effect and then return to the initial value under the corresponding transient operating point; Step 4: Based on the pressure disturbance amplitude and pressure adjustment time of the intake cavity at each transition state operating point, as well as the total air flow rate, intake cavity pressure, and intake total temperature of the intake cavity at the corresponding transition state operating point, a dynamic disturbance model is constructed with the total air flow rate, intake cavity pressure, and intake total temperature of the intake cavity as coordinate axes and the pressure disturbance amplitude and pressure adjustment time as coordinate values; In this embodiment, based on the model established in step 1 and with the relevant data in step 2 as input, the disturbance process of the intake pressure during the transient state test is simulated to obtain the amplitude and process time of the total pressure of the intake chamber deviating from the expected value after being disturbed during the dynamic response test process. The obtained data is used to form a dynamic disturbance model with the total air flow rate of the intake chamber, the intake chamber pressure, and the total intake temperature as coordinate axes, as shown in the following example. Figure 4 .

[0023] Step 5: Experimentally obtain actual values of the pressure disturbance amplitude and the pressure adjustment time of the aircraft engine at a transient state test point, and input the total air flow rate, total intake air temperature, and intake chamber pressure data collected during the transient state test of the aircraft engine into the dynamic disturbance model to analyze and obtain simulated values of the pressure disturbance amplitude and the pressure adjustment time of the aircraft engine at the corresponding transient state; Step 6: quantify the nonlinear dynamic errors between the pressure disturbance amplitude simulation value and the pressure adjustment time simulation value output by the dynamic disturbance model and the corresponding measured values by using a dynamic weighted integral error analysis method to obtain a normalized weighted integral error index; taking the normalized weighted integral error index as not greater than a first preset threshold and the error between the intake chamber pressure simulation value and the measured value as not greater than a second preset threshold as optimization goals, use a single-objective gradient descent optimization method to iteratively update the learning parameters in the negative gradient direction to optimize the dynamic disturbance model, and obtain an optimized dynamic disturbance model; In this embodiment, based on the key parameters such as the total air flow rate of the intake cavity, the total intake temperature, and the intake cavity pressure collected during the transition state test process, the original data is denoised (wavelet threshold denoising) and time-frequency aligned to eliminate the influence of environmental noise and sensor delay. The relevant data is then input into the dynamic disturbance model, and the simulated output of the cavity pressure is compared with the measured data to define dynamic error indicators, including amplitude error, phase delay, etc. The nonlinear dynamic error between the calculated value of the process model and the actual value is quantified by weighted dynamic weighted integral error to obtain the normalized weighted integral error indicator. ,in is the simulated value of the pressure disturbance amplitude output by the dynamic disturbance model at time t, is the total intake pressure collected at time t, is the starting time of the transition state, is the end time of the transition state, is the time constant of the exponential decay weight, The value range is 0.1 to 3.

[0024] By using the normalized weighted integral error index as the optimization target, a single-objective gradient descent optimization method is used. , iteratively update the learning parameters along the negative gradient direction to optimize the model until the normalized weighted integral error index ≯2%. In the above formula, is the model parameter at the k+1th iteration (mainly the model to be optimized), is the model parameter at the kth iteration, is the learning rate, is the bias vector of the model parameters, indicating the direction of change of the current parameters. The MSE is minimized by iteratively adjusting the learning rate and model parameters until the deviation between the simulated pressure entering the cavity and the measured pressure is ≤10%.

[0025] Step 7: Based on the current deviation value of the intake chamber pressure, a feedforward control law for the intake chamber is established based on the feedforward compensation of each intake branch. The intake chamber pressure differential is obtained based on the optimized dynamic disturbance model analysis. The integral and deviation of the intake chamber pressure differential within each calculation cycle of the PLC controller are used as inputs. The feedforward compensation of each intake branch is calculated using the feedforward control law of the intake chamber to obtain the feedforward compensation for each intake branch that satisfies the total air flow rate compensation of the intake chamber during the transient state test of the aircraft engine. In this embodiment, a real-time settlement framework for feedforward control quantity during the test process is established (eg Figure 5 ), the intake cavity pressure differential calculated based on the specific test point flow and the optimized dynamic disturbance model The integral and deviation in each calculation cycle are input, and the feedforward control law through the intake cavity is: The feedforward compensation is calculated, where is the differential pressure of the intake chamber, V is the volume of the intake cavity, is the specific heat of air, R is the gas constant, For the The air flow of the intake branch, is the intake air flow of the engine, For the The feedforward compensation of each branch is: is the current deviation value of the intake chamber pressure, is the differential deviation of the current intake chamber pressure, For the The proportional gain of the intake branch, The value range is 1.2~2.4, For the The differential gain of the intake branch, The value range is 0.2 to 0.6.

[0026] Compared with existing control law calculation methods, the method for obtaining the feedforward control law in the present invention is closer to engineering practice and more universal. Furthermore, through the dynamic changes in the total intake pressure and the feedforward control law model, the feedforward control quantity under the corresponding operating conditions is obtained in real time. Through the open-loop feedforward method, the upcoming large disturbance in the total intake pressure can be suppressed in advance before the feedback-based closed-loop control system takes effect, thereby improving the simulation quality of the system in transient state tests. This method has significant engineering practical value in the field of high-altitude cabin environment construction technology and plays an important role in promoting the design and application of other subsequent large-scale high-altitude cabin environment simulation systems.

[0027] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A feedforward control law design method based on a large cavity effect model, characterized in that: include: Step 1: Construct a simulation model of an air intake chamber for aircraft engine testing. The air intake chamber is used to provide an air environment for aircraft engine testing. The air intake chamber is provided with an exhaust branch and multiple air intake branches, and each of the air intake branches is provided with a control valve for controlling air flow; Step 2: Using the total intake temperature, total intake pressure, starting flow rate, end flow rate, and process flow rate change time of multiple typical transient operating points of the aircraft engine as input, the simulation model is used for simulation analysis to obtain a pressure change curve of the intake chamber at each transient operating point; the typical transient operating points include operating points where the throttle lever changes from slow to maximum state within a preset time under different flight altitude conditions; Step 3: Extracting the pressure disturbance amplitude and pressure adjustment time of the intake chamber based on the pressure change curve at each transient operating point; the pressure adjustment time is the time it takes for the initial value of the chamber pressure before the engine state changes to deviate due to the transient state effect and then return to the initial value under the corresponding transient operating point; Step 4: Based on the pressure disturbance amplitude and pressure adjustment time of the intake cavity at each transition state operating point, as well as the total air flow rate, intake cavity pressure, and intake total temperature of the intake cavity at the corresponding transition state operating point, a dynamic disturbance model is constructed with the total air flow rate, intake cavity pressure, and intake total temperature of the intake cavity as coordinate axes and the pressure disturbance amplitude and pressure adjustment time as coordinate values; Step 5: Experimentally obtain actual values of the pressure disturbance amplitude and the pressure adjustment time of the aircraft engine at a transient state test point, and input the total air flow rate, total intake air temperature, and intake chamber pressure data collected during the transient state test of the aircraft engine into the dynamic disturbance model to analyze and obtain simulated values of the pressure disturbance amplitude and the pressure adjustment time of the aircraft engine at the corresponding transient state; Step 6: quantify the nonlinear dynamic errors between the pressure disturbance amplitude simulation value and the pressure adjustment time simulation value output by the dynamic disturbance model and the corresponding measured values by using a dynamic weighted integral error analysis method to obtain a normalized weighted integral error index; The normalized weighted integral error index is no greater than a first preset threshold, and the error between the simulated value and the measured value of the intake chamber pressure is no greater than a second preset threshold as optimization objectives, and the dynamic disturbance model is optimized by iteratively updating the learning parameters along the negative gradient direction using a single-objective gradient descent optimization method to obtain an optimized dynamic disturbance model; Step seven: According to the current deviation value of the intake chamber pressure, a feedforward control law for the intake chamber based on the feedforward compensation amount of each intake branch is established, and the intake chamber pressure differential is obtained according to the optimized dynamic disturbance model analysis. The integral and deviation of the intake chamber pressure differential in each PLC controller calculation cycle are used as input, and the feedforward compensation amount of each intake branch is calculated through the feedforward control law of the intake chamber to obtain the feedforward compensation amount of each intake branch that meets the total air flow compensation of the intake chamber during the transient state test of the aircraft engine.

2. The feedforward control law design method based on the large cavity effect model according to claim 1 is characterized in that: Normalized weighted integral error index in step 6 ,in is the simulated value of the pressure disturbance amplitude output by the dynamic disturbance model at time t, is the total intake pressure collected at time t, is the starting time of the transition state, is the end time of the transition state, is the time constant of the exponential decay weight, The value range is 0.1 to 3.

3. The feedforward control law design method based on the large cavity effect model according to claim 1 is characterized in that: In step 7, the feedforward control law of the intake chamber based on the feedforward compensation of each intake branch is established as ,in For the The feedforward compensation of each branch is: is the current deviation value of the intake chamber pressure, is the differential deviation of the current intake chamber pressure, For the The proportional gain of the intake branch, The value range is 1.2~2.4, For the The differential gain of the intake branch, The value range is 0.2 to 0.

6.

4. The feedforward control law design method based on the large cavity effect model according to claim 1 is characterized in that: In step 7, the pressure differential of the intake chamber is , is the differential pressure of the intake chamber, V is the volume of the intake cavity, is the specific heat of air, R is the gas constant, For the The air flow of the intake branch, is the intake air flow of the engine.

5. A feedforward control law design system based on a large cavity effect model, used to implement the feedforward control law design method based on a large cavity effect model according to claim 1, characterized in that: include: A simulation model construction module is used to construct a simulation model of an intake chamber for aircraft engine testing, wherein the intake chamber is used to provide an air environment for aircraft engine testing, the intake chamber is provided with an exhaust branch and multiple intake branches, and each of the intake branches is provided with a control valve for controlling air flow; a simulation analysis module for using the simulation model to analyze and obtain a pressure variation curve of the intake chamber at each transition state operating point using the total intake temperature, total intake pressure, starting flow rate, end flow rate, and process flow rate variation time at multiple typical transition state operating points of the aircraft engine; the typical transition state operating points include operating points where the throttle lever changes from an idle state to a maximum state within a preset time at different flight altitudes; a data acquisition module for extracting the pressure disturbance amplitude and pressure adjustment time of the intake chamber based on the pressure change curve at each transient operating point; the pressure adjustment time being the time it takes for the initial value of the chamber pressure to deviate from the initial value due to the transient state influence before the engine state changes under the corresponding transient operating point to return to the initial value; a disturbance model construction module for constructing a dynamic disturbance model with the total air flow rate of the intake chamber, the intake chamber pressure, and the total intake air temperature as coordinate axes and the pressure disturbance amplitude and the pressure adjustment time as coordinate values, based on the pressure disturbance amplitude and the pressure adjustment time of the intake chamber at each transient operating point, as well as the total air flow rate of the intake chamber, the intake chamber pressure, and the total intake air temperature at the corresponding transient operating point; a data analysis module for inputting, based on the actual measured values of the pressure disturbance amplitude and the actual measured values of the pressure adjustment time of the aircraft engine at the transient state test point obtained in the test, the total air flow rate, the total intake air temperature, and the intake chamber pressure data collected during the transient state test of the aircraft engine into the dynamic disturbance model, and analyzing to obtain simulated values of the pressure disturbance amplitude and the pressure adjustment time of the aircraft engine at the corresponding transient state; The model optimization module is used to quantify the nonlinear dynamic errors between the pressure disturbance amplitude simulation value and the pressure adjustment time simulation value output by the dynamic disturbance model and the corresponding measured values through the dynamic weighted integral error analysis method to obtain the normalized weighted integral error index; The normalized weighted integral error index is no greater than a first preset threshold, and the error between the simulated value and the measured value of the intake chamber pressure is no greater than a second preset threshold as optimization objectives, and the dynamic disturbance model is optimized by iteratively updating the learning parameters along the negative gradient direction using a single-objective gradient descent optimization method to obtain an optimized dynamic disturbance model; The compensation analysis module is used to establish a feedforward control law for the intake chamber based on the feedforward compensation of each intake branch according to the current deviation value of the intake chamber pressure, and obtain the intake chamber pressure differential according to the optimized dynamic disturbance model analysis. The integral and deviation of the intake chamber pressure differential in each PLC controller calculation cycle are used as input, and the feedforward compensation of each intake branch is calculated through the feedforward control law of the intake chamber to obtain the feedforward compensation of each intake branch that meets the total air flow compensation of the intake chamber during the transient state test of the aircraft engine.

6. The feedforward control law design system based on the large cavity effect model according to claim 5 is characterized in that: In the model optimization module, the normalized weighted integral error index ,in is the simulated value of the pressure disturbance amplitude output by the dynamic disturbance model at time t, is the total intake pressure collected at time t, is the starting time of the transition state, is the end time of the transition state, is the time constant of the exponential decay weight, The value range is 0.1 to 3.

7. The feedforward control law design system based on the large cavity effect model according to claim 5 is characterized in that: In the compensation analysis module, the feedforward control law of the intake cavity based on the feedforward compensation of each intake branch is established as follows: ,in For the The feedforward compensation of each branch is: is the current deviation value of the intake chamber pressure, is the differential deviation of the current intake chamber pressure, For the The proportional gain of the intake branch, The value range is 1.2~2.4, For the The differential gain of the intake branch, The value range is 0.2 to 0.

6.

8. The feedforward control law design system based on the large cavity effect model according to claim 5 is characterized in that: In the compensation analysis module, the intake chamber pressure differential , is the differential pressure of the intake chamber, V is the volume of the intake cavity, is the specific heat of air, R is the gas constant, For the The air flow of the intake branch, is the intake air flow of the engine.

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