Design method of aero-engine high-altitude simulation test-bed intake control node under distributed architecture

Abstract

The application discloses a design method of an air intake control node of an aero-engine high-altitude simulation test bench under a distributed architecture, and is aimed at a high-altitude test bench air intake control system, wherein the control object of the high-altitude test bench air intake control system is a high-temperature simulation gas path, a high-altitude cabin cooling gas path and a low-temperature simulation gas path of the high-altitude test bench; the high-altitude test bench air intake control system comprises a hardware part and a software part; the hardware part is a physical structure of the high-altitude test bench air intake control system, is composed of electronic element integrated circuits and chips, and controls the high-temperature simulation gas path, the high-altitude cabin cooling gas path and the low-temperature simulation gas path through the hardware part; and the software part is a software program downloaded into the hardware structure and realizes corresponding control functions in cooperation with the hardware part. The design method can well complete communication of each gas path subsystem under the architecture, realizes that each branch subsystem of the air intake system can more quickly and accurately complete rapid mixing of gas to meet the continuous simulation requirement of an engine flight task along a preset profile.

Description

Technical Field

[0001] This invention belongs to the field of high-altitude continuous environment simulation technology for aero-engines, and relates to a design method for an air intake control system of a high-altitude simulation test stand. Specifically, it is a method for the control structure, control method and actuator of the air intake control node in the distributed control structure of a high-altitude test stand. Background Technology

[0002] A high-altitude simulation test bench for aero-engines, or simply a high-altitude test bench, is a system of equipment that simulates the flight conditions and environment of an aircraft engine in the air. It conducts high-altitude simulation tests on the entire engine and its components, and is an indispensable means of developing advanced aero-engines and their improvements. A high-altitude continuous simulation test bench is a large-scale ground-based facility used to test and evaluate the performance indicators of an aero-engine and its various functional components during high-altitude operations. Among these, the intake and exhaust control system is the core control equipment for high-altitude environment simulation. Its main function is to establish the necessary flight conditions for the engine by adjusting the engine's intake pressure and temperature, as well as the environmental pressure in the test chamber, including at different flight speeds, high-altitude pressures, and high-altitude temperatures. Accurately achieving the aero-engine's flight conditions is a key factor in the precise simulation capabilities of the high-altitude test bench.

[0003] The air intake control system of a high-altitude test stand refers to the system used to control the entry and flow of gas into a spacecraft or aircraft in an high-altitude environment. The importance of this system in high-altitude test stands cannot be underestimated because the high-altitude environment differs significantly from ground conditions, including differences in atmospheric pressure, temperature, and gas density. Some key functions and components of the air intake control system of a high-altitude test stand include: the air inlet, the starting point of the system, located outside the spacecraft or aircraft, used to introduce gas from the high-altitude environment into the test stand. The design and location of the air inlet must take into account the air pressure and temperature conditions at high altitudes to ensure efficient gas introduction. The air intake regulating valve is a key component for controlling gas flow; it can adjust the gas flow rate and velocity to meet experimental requirements and ensure stable and controllable air intake flow. The air intake filter, located at the air inlet or in the air intake duct, is used to filter out possible impurities and particles to ensure that the gas entering the test stand is clean and pure, avoiding damage to the spacecraft or aircraft. Air intake temperature and pressure sensors are used to monitor the air intake temperature and pressure.

[0004] The air intake control system of a high-altitude test stand is a complex system that requires precise design and careful testing to ensure a stable and reliable gas supply in high-altitude environments and to meet test requirements. These systems play a crucial role in the testing and evaluation of spacecraft and aircraft, helping engineers better understand the performance and behavior of aero-engines. Summary of the Invention

[0005] This invention provides a design scheme for the air intake control node of a high-altitude simulation test stand for aero-engines under a distributed architecture. Specifically, the air intake node of the high-altitude test stand achieves rapid gas mixing through the high-temperature simulation gas path, the high-altitude cabin cooling gas path, and the low-temperature simulation gas path of the air supply regulation system to meet the continuous simulation requirements of the engine flight mission along a preset profile.

[0006] The entire node comprises a controller, sensors, and actuators, collectively forming a semi-physical simulation platform. Its control logic can be used to control the intake and exhaust systems of actual high-altitude test platforms, thereby shortening the development cycle and reducing testing costs.

[0007] The technical solution of the present invention:

[0008] A design method for an air intake control node of an aero-engine high-altitude simulation test stand under a distributed architecture is proposed for the air intake control system of the high-altitude test stand. The control objects of the air intake control system of the high-altitude test stand are the high-temperature simulation air path, the high-altitude cabin cooling air path and the low-temperature simulation air path of the high-altitude test stand.

[0009] The high-altitude test station's air intake control system consists of hardware and software components. The hardware component is the physical structure of the high-altitude test station's air intake control system, composed of electronic components, integrated circuits, and chips. The hardware component controls the high-temperature simulated air path, the high-altitude cabin cooling air path, and the low-temperature simulated air path. The software component is the software program downloaded into the hardware structure, which works in conjunction with the hardware to achieve the corresponding control functions.

[0010] The design of the high-altitude test platform's air intake control system involves both hardware and software design.

[0011] The hardware design of the high-altitude test platform air intake control system is as follows: The hardware mainly consists of an electro-hydraulic servo valve, a regulating valve, a valve position sensor, an analog signal conditioning module, a serial communication module, and a controller. This enables the high-altitude test platform air intake control system to perform the following functions: receiving commands from the host computer, parsing and processing the command data, entering the control cycle and completing the control algorithm calculation, and outputting the result of the control algorithm calculation to the electro-hydraulic servo valve and the regulating valve; the electro-hydraulic servo valve and the regulating valve execute the control algorithm calculation result and feed back the valve position change signal to the controller through the valve position sensor, thus completing the closed-loop control of the high-altitude test platform air intake control system.

[0012] The electro-hydraulic servo valve and regulating valve are used to execute the results calculated by the controller's output control algorithm. By controlling the opening and closing of the electro-hydraulic servo valve and regulating valve, air at different temperatures and pressures is provided to the intake system. The regulating valve needs to feed back flow information to the controller, and its flow characteristic model is as follows:

[0013]

[0014] in, For valve flow rate, α x Where p1 is the valve flow coefficient, p2 is the upstream static pressure, and S is the downstream static pressure. x Where R is the flow area of ​​the valve, T1 is the gas thermodynamic constant, and T1 is the static temperature of the gas before the valve.

[0015] The valve position sensor is used to measure the opening degree of the electro-hydraulic servo valve and the regulating valve, and calculates the valve flow area. The valve position opening information and flow area information are fed back to the controller. The controller's control algorithm calculates and forms a position closed-loop control. At the same time, the valve flow rate is calculated in the controller through the regulating valve flow characteristic model and fed back to the host computer for display.

[0016] The controller uses a digital signal processor (DSP). The DSP chip can run control programs, parse and process instructions received from the host computer, enter the control cycle and complete the control algorithm calculation. The DSP realizes the control function of the high-altitude platform air intake control system through the circuit modules integrated on the chip, including an enhanced pulse width modulation output module and an enhanced analog-to-digital converter module.

[0017] Enhanced Pulse Width Modulation (EPWM) Output Module: The enhanced pulse width modulation output module obtains the analog square wave signal required by the digital signal processor by adjusting the duty cycle and frequency in its own parameters. The enhanced pulse width modulation output module outputs the analog square wave signal to the electro-hydraulic servo valve and the regulating valve to realize valve position control.

[0018] Enhanced Analog-to-Digital Converter (ADC) Module: The enhanced analog-to-digital converter module acquires the analog signal from the valve position sensor, converts the signal into a digital signal, and processes the data to obtain the feedback information from the valve position sensor;

[0019] The analog signal conditioning module mainly consists of four operational amplifier circuits with a reference voltage of -2.5V. It conditions external analog signals of ±10V to 0-3V for direct input to the ADC input pin of the digital signal processor. The conditioning theory formula of the analog signal conditioning module is the relationship between the input signal amplitude and the acquired digital value:

[0020] V0=(250 / 24.9-300*D / (4095*15))

[0021] Where V0 represents the amplitude of the actual signal, and D represents the digital value after ADC conversion;

[0022] The serial communication module is the physical layer driver of the distributed communication bus, used to receive instructions from the host computer. After the communication protocol is satisfied, the digital signal processor receives the running instructions from the host computer through the serial communication module and sends the feedback information calculated in the controller to the host computer.

[0023] The software is designed as a distributed communication bus, including a container network interface (Analog to Digital Converter, or ADC for short), data frame definition, physical layer driver module and CRC check, and the protocol adopts RS485 serial port protocol.

[0024] The software is designed for bare-metal programming, and the program is burned into the controller through the Code Composer Studio (CCS) platform. The program structure is mainly based on a control loop structure and consists of various functional modules, including a system initialization module, a control parameter initialization module, an analog signal reading module, a control algorithm calculation module, and a signal output module. Among them, the system initialization module and the control parameter initialization module are sequential and are executed sequentially at the beginning of the program to complete the initialization of the system. The remaining modules form a control loop structure, with one loop consisting of the analog signal reading module, the control algorithm calculation module, and the signal output module.

[0025] The control logic and steps for completing the high-altitude test platform air intake control system are as follows:

[0026] S1: The controller of the high-altitude test chamber air intake control system starts running. First, it performs initialization, including reading the initial control parameters of the system, the initial temperature and pressure of the cavity, and setting the simulation step size; then it enters the control loop structure.

[0027] S2: The host computer transmits control commands, including temperature and pressure, to the controller of the high-altitude test platform's air intake control system via the communication bus. The controller then uploads real-time data from the high-altitude test platform's air intake control system to the host computer.

[0028] S3: The enhanced analog-to-digital converter module collects information from the valve position sensor and calculates the valve opening data through the analog conditioning module; the controller calculates the gas flow rate and pressure data through the opening data and the pressure data of the gas before and after the valve.

[0029] S4: The controller of the high-altitude test platform air intake control system calculates the gas pressure and flow data through the cavity characteristic model, and inputs them into the control algorithm along with the upper computer command data. The calculation results are then output to the electro-hydraulic servo valve and the regulating valve through the enhanced pulse width modulation output module.

[0030] S5: The electro-hydraulic servo valve and the regulating valve generate valve position changes. The enhanced analog-to-digital converter module acquires the new analog signal from the valve position sensor and enters a new control cycle, completing the closed-loop control of the high-altitude platform's air intake control system.

[0031] The beneficial effects of this invention are as follows: The distributed architecture of the aero-engine high-altitude simulation test stand in this invention can effectively complete the communication between the high-altitude test stand inlet control system and the host computer, enabling the high-altitude test stand inlet system to complete the rapid mixing of gases more quickly and accurately to meet the continuous simulation requirements of engine flight missions along a preset profile. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the air intake control principle for a high-altitude test bench of an aircraft engine.

[0033] Figure 2 This is a diagram of the data frame structure.

[0034] Figure 3 This is the controller software flowchart.

[0035] Figure 4 This is a structural diagram of the air intake system control system for an aero-engine at high altitude.

[0036] Figure 5 This is a structural diagram of the high-temperature simulation gas circuit subsystem.

[0037] Figure 6 This is a structural diagram of the low-temperature simulation gas circuit subsystem.

[0038] Figure 7 This is a structural diagram of the cooling air circuit subsystem. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings and technical solutions.

[0040] The high-altitude test platform's air intake control system is designed in both hardware and software aspects. The hardware components include... Figure 1 As shown in the figure, the control principle of the high-altitude air intake system of an aero-engine under a distributed architecture includes an electro-hydraulic servo valve and regulating valve, a valve displacement sensor, an enhanced analog-to-digital converter module, a serial communication module, and a DSP controller.

[0041] The serial communication module, enhanced analog-to-digital converter module, and enhanced pulse width modulation output module are integrated on the integrated circuit board of the DSP controller; while the signal conditioning circuit, electro-hydraulic servo valve, and regulating valve are composed of peripheral circuits.

[0042] The design functions of each module are explained in detail below:

[0043] (1) Serial communication module

[0044] To meet the communication requirements of the distributed system of the high-altitude air intake control system, the communication modules all adopt the RS485 communication protocol, which enables many-to-many communication. The communication parameters are set as follows: baud rate 115200, data bits 8 bits, no parity check, and stop bits 1. The data frame structure is as follows... Figure 2 As shown, it consists of 12 bytes. 0x66 is the data header, followed by two address bits, a command bit, and a device type bit. The host computer uses these four bits to distinguish the controller addresses of the high-temperature simulation gas circuit, the high-altitude cabin cooling gas circuit, and the low-temperature simulation gas circuit, and to determine the send and receive status with the upper controller. Then there are two data bits used to transmit data information. Reserved bits are for reserved status.

[0045] The last two bytes of the data frame are checksum bits, used to ensure correct communication between the two parties. The communication protocol uses the CRC16 checksum algorithm. Both the host computer and the controller of the high-altitude air intake control system perform data verification. A complete verification process between the sender and receiver is as follows:

[0046] S1: The sender calculates two bytes of check bits after processing the first 10 bytes of data using the CRC_16_MODBUS algorithm.

[0047] S2: The first 10 bytes of data are combined with two checksums to form a complete 12 bytes, which are then sent out through the sender's communication module.

[0048] S3: After receiving the data, the receiver splits the data into two parts. The first 10 bits of data are used to obtain two new check bits through the CRC_16_MODBUS algorithm, and are compared with the two received bits to see if they are the same.

[0049] S4: If the comparison results are the same, the first 10 bytes of data are sent to the controller for processing. If the comparison results are different, the first 10 bytes of data are cleared, and an error is reported to the sender.

[0050] The communication protocol and verification method of this module ensure the correctness of communication information between the controller and the host computer in the high-altitude platform air intake control system, improve the accuracy of data, and enable the control system to more accurately implement the instructions of the host computer.

[0051] (2) Enhanced analog-to-digital converter module

[0052] The enhanced analog-to-digital converter (ADC) module's main function is to convert analog signals into digital signals. In this invention, this module is integrated on a DSP development board, operating at a frequency of 25MHz, capable of continuous sampling, and with a maximum sampling channel of 16. Each time the module samples analog data from the valve position sensor, it records 10 data points. The maximum and minimum values ​​are removed from these 10 data points, and the average of the remaining sums is calculated to obtain the processed data. The processed data is then used to calculate the specific displacement value according to the displacement conversion formula, and the data is output to the controller's calculation module.

[0053] (3) Controller's computing module

[0054] This module is primarily implemented in the controller by a 32-bit CPU timer of the DSP controller. This timer interrupts every 20ms according to the control cycle. During the interrupt, the module calculates the command data received by the serial communication module and the signal data acquired by the ADC, and outputs the calculation results to the electro-hydraulic servo valve and the regulating valve. The specific functional steps are as follows:

[0055] S1: Receives instruction data from the host computer via serial communication module and data converted by the signal acquisition module after sampling, compares the two within the allowable error range.

[0056] S2: If the comparison results are the same, the interrupt ends, and the system waits for the next interrupt control cycle. If the comparison results are different, the two sets of data are loaded into the control algorithm to obtain the calculation result.

[0057] S3: The controller outputs the calculation results to the regulating valve drive circuit through the signal output module, ends the current control cycle, and waits to enter the next control cycle.

[0058] This module ensures that the high-altitude test platform's air intake control system can calculate the results through algorithms within a certain time range, and then execute the host computer's instructions through the signal output module.

[0059] (4) Analog Conditioning Module

[0060] The analog signal conditioning module is mainly used to condition the analog signal from the valve position sensor into a 0-3V analog signal so that it can be directly fed into the ADC input pin of the DSP. The conditioning theory formula for this module is the relationship between the input signal amplitude and the acquired digital value:

[0061] V0=(250 / 24.9-300*D / (4095*15))

[0062] Where V0 represents the amplitude of the actual signal, and D represents the digital value after ADC conversion.

[0063] The program portion of this invention was written and debugged on the CCS platform, and then burned into the DSP controller. The program design structure is mainly based on a control loop structure, including a system initialization module, a control parameter initialization module, an analog signal reading module, a control algorithm calculation module, and a signal output module.

[0064] Figure 3 This is the controller software flowchart. The DSP controller program performs system initialization during the initialization phase, including interrupt configuration, function and variable initialization, and setting of control cycle, formula parameters, and algorithm parameters. It then enters the loop control program.

[0065] In the cyclic control program, the DSP controller reads control commands from the host computer and transmits debugging data and controller operation data via the serial communication module. The ADC acquisition module collects simulated data from the high-altitude test bench's air intake system through the valve position sensor. This data is then used to calculate the control valve flow characteristic model, and the resulting control valve flow data is transmitted to the DSP controller's calculation module. The calculation module performs control algorithm calculations to obtain the control quantity for the control valve. This control quantity is output to the control valve through the EPWM module, completing one cycle of the control program. Then, it waits to enter the next control cycle.

[0066] Figure 4 This is a structural diagram of the high-altitude test bench air intake control system for an aero-engine. In this system, the high-temperature simulation air path, the high-altitude cabin cooling air path, and the low-temperature simulation air path each have their corresponding controllers, integrated functional modules, regulating valve groups, valve position sensors, and software control programs. The hardware design structure and software flow of each air path are identical; the only difference lies in the program setting parameters caused by variations in the number and function of the regulating valves. These three air path control systems constitute a distributed architecture high-altitude test bench air intake control system.

[0067] Figure 5 It is a structural diagram of a high-temperature simulated gas circuit control system. Figure 6 It is a structural diagram of the high-altitude cabin cooling air circuit control system and Figure 7 This is a structural diagram of a cryogenic simulation gas path control system. Each gas path control system includes a controller, an electro-hydraulic servo valve, a regulating valve assembly, a valve position sensor, and a valve flow characteristic module. The hardware structure of each gas path control system is identical, and they employ the same control logic; the only difference lies in the number and function of the regulating valves. The software design of each gas path control system conforms to the aforementioned software design process, and their common control logic is as follows:

[0068] S1: The host computer transmits commands to the control system via the communication bus. Each gas circuit control system receives the commands through the serial communication module, performs CRC verification on the command data, and then begins to execute the instructions.

[0069] S2: The valve position change module obtains the valve opening value of the regulating valve. The valve flow calculation unit calculates the flow rate using the pressure values ​​before and after the valve opening value, and then uses the formula...

[0070]

[0071] Obtain the flow rate data of the cavity characteristic module.

[0072] S3: The DSP controller block performs algorithm calculations based on the control instructions from the host computer and the flow data from the cavity characteristic module, and outputs the results to the electro-hydraulic servo valve and the regulating valve.

[0073] S4: The electro-hydraulic servo valve and the regulating valve generate valve position changes. The enhanced analog-to-digital converter module acquires the new analog signal from the valve position sensor, completing the closed-loop control of the high-altitude simulation subsystem. Then it waits to enter the next control cycle.

[0074] The high-altitude test station's air intake control system, with its distributed structure, can effectively communicate between each air path controller and the host computer. Each air path can more quickly and accurately control the gas, thereby achieving rapid mixing to meet the continuous simulation requirements of the engine flight mission along the preset profile.

Claims

1. A design method for an air intake control node on a high-altitude simulation test stand for aero-engines under a distributed architecture, characterized in that, This design method is for the air intake control system of the high-altitude test platform. The controlled objects of the air intake control system are the high-temperature simulation air path, the high-altitude cabin cooling air path, and the low-temperature simulation air path of the high-altitude test platform. The high-altitude test station's air intake control system consists of hardware and software components. The hardware component is the physical structure of the high-altitude test station's air intake control system, composed of electronic components, integrated circuits, and chips. The hardware component controls the high-temperature simulated air path, the high-altitude cabin cooling air path, and the low-temperature simulated air path. The software component is the software program downloaded into the hardware structure, which works in conjunction with the hardware to achieve the corresponding control functions. The design of the high-altitude test platform's air intake control system involves both hardware and software design. The hardware design of the high-altitude test platform air intake control system is as follows: The hardware mainly consists of an electro-hydraulic servo valve, a regulating valve, a valve position sensor, an analog signal conditioning module, a serial communication module, and a controller. This enables the high-altitude test platform air intake control system to perform the following functions: receiving commands from the host computer, parsing and processing the command data, entering the control cycle and completing the control algorithm calculation, and outputting the result of the control algorithm calculation to the electro-hydraulic servo valve and the regulating valve; the electro-hydraulic servo valve and the regulating valve execute the control algorithm calculation result and feed back the valve position change signal to the controller through the valve position sensor, thus completing the closed-loop control of the high-altitude test platform air intake control system. The software is designed as a distributed communication bus, including container network interface, data frame definition, physical layer driver module and CRC check, and the protocol adopts RS485 serial port protocol; The software is designed for bare-metal programming, and the software program is burned into the controller through the CCS platform. The program design structure is mainly based on a control loop structure and consists of various functional modules, including a system initialization module, a control parameter initialization module, an analog signal reading module, a control algorithm calculation module, and a signal output module. Among them, the system initialization module and the control parameter initialization module are sequential and are executed sequentially at the beginning of the software program to complete the initialization of the system. The remaining modules form a control loop structure, with one loop consisting of the analog signal reading module, the control algorithm calculation module, and the signal output module. The valve position sensor is used to measure the opening degree of the electro-hydraulic servo valve and the regulating valve, and calculates the valve flow area. The opening degree and valve flow area of ​​the electro-hydraulic servo valve and the regulating valve are fed back to the controller. The controller's control algorithm calculates and forms a position closed-loop control. At the same time, the valve flow rate is calculated in the controller through the regulating valve flow characteristic model and fed back to the host computer for display.

2. The design method according to claim 1, characterized in that, The electro-hydraulic servo valve and regulating valve are used to execute the results calculated by the controller's output control algorithm. By controlling the opening and closing of the electro-hydraulic servo valve and regulating valve, air at different temperatures and pressures is provided to the intake system. The regulating valve needs to feed back flow information to the controller, and its flow characteristic model is as follows: in, For valve flow rate, For valve flow coefficient, The static pressure before the valve, This refers to the static pressure after the valve. For valve flow area, The thermodynamic constant of the gas, The static temperature of the gas before the valve.

3. The design method according to claim 1, characterized in that, The controller uses a digital signal processor (DSP). Software programs can run on the DSP chip to parse and process instructions received from the host computer, enter the control cycle, and complete the control algorithm calculation. The DSP realizes the control function of the high-altitude platform air intake control system through circuit modules integrated on the chip, including an enhanced pulse width modulation output module and an enhanced analog-to-digital converter module. Enhanced Pulse Width Modulation Output Module: The enhanced pulse width modulation output module obtains the analog square wave signal required by the digital signal processor by adjusting the duty cycle and frequency in its own parameters. The enhanced pulse width modulation output module outputs the analog square wave signal to the electro-hydraulic servo valve and the regulating valve to realize valve position control. Enhanced Analog-to-Digital Converter Module: The enhanced analog-to-digital converter module acquires analog signals from the valve position sensor, converts the analog signals into digital signals, and processes the data to obtain feedback information from the valve position sensor.

4. The design method according to claim 1, characterized in that, The analog signal conditioning module mainly consists of four operational amplifier circuits with a reference voltage of -2.5V. It conditions external analog signals of ±10V to 0-3V for direct input to the ADC input pin of the digital signal processor. The conditioning theory formula of the analog signal conditioning module is the relationship between the input signal amplitude and the acquired digital value: in, Indicates the amplitude of the input signal. This represents the acquired digital value after ADC conversion.

5. The design method according to claim 1, characterized in that, The serial communication module is the physical layer driver of the distributed communication bus, used to receive instructions from the host computer. After the communication protocol is satisfied, the digital signal processor receives the running instructions from the host computer through the serial communication module and sends the feedback information calculated in the controller to the host computer.

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