CN213180398U - Test system for large-area temperature distribution of hypersonic-speed high-temperature wind tunnel - Google Patents

Abstract

The utility model discloses a test system for hypersonic high temperature wind-tunnel large tracts of land temperature distribution, include: the measurement and control unit is communicated with the remote upper computer through a network cable and is configured to comprise a measurement and control host, and a main control module and a host acquisition module which are arranged in the measurement and control host; carry out data communication through cable and observing and controling the host computer to carry out the data acquisition unit of gathering to wind-tunnel large tracts of land temperature distribution, it is configured as including 8 collection front ends and rather than matched with thermocouple group. The utility model provides a test system for hypersonic high temperature wind-tunnel large tracts of land temperature distribution, it is through providing a modular temperature measuring device, realize the temperature measurement of 128 passageways through a system, the integrated level, require lowly to the application model scope of thermocouple, and modular intensity is high, have miniaturization, low-power consumption, high reliability, characteristics that anti-interference is strong, so it can be applied to in hypersonic high temperature wind-tunnel large tracts of land temperature distribution measurement test betterly.

Description

Test system for large-area temperature distribution of hypersonic-speed high-temperature wind tunnel

Technical Field

The utility model belongs to the technical field of hypersonic high temperature wind tunnel test, concretely relates to a test system for hypersonic high temperature wind tunnel large tracts of land temperature distribution.

Background

The hypersonic speed high-temperature wind tunnel test environment electrical equipment is various, high-power servo motors, hydraulic control systems, model attitude control systems and other equipment cause strong interference, and the field electrical noise value is high. In a large-area temperature distribution measurement test, signals of K-type thermocouples, S-type thermocouples and iridium-rhodium thermocouples are very weak, and thermocouple signals are submerged in electrical noise in the test, so that temperature test values fluctuate, and errors are large. And the cold end of the thermocouple changes along with the temperature of the high-temperature environment of the wind tunnel, and the output value of the cold end also changes all the time.

The general temperature test equipment has low A/D conversion digit, low signal-to-noise ratio, great influence of noise on thermocouple voltage signals, inaccurate cold end test system and great deviation of temperature measurement data and actual values. In addition, because the hypersonic speed high-temperature wind tunnel test environment is high vacuum, high temperature, strong interference and strong pollution, the conventional temperature test equipment cannot run in the hypersonic speed high-temperature wind tunnel test environment, and the temperature test equipment needs to be modularized and installed in a test model, so that the temperature measurement module is required to have the characteristics of miniaturization, low power consumption, high reliability and strong interference resistance, and meanwhile, because large-area temperature distribution of the high-temperature wind tunnel needs to be measured, the integration level of the existing equipment is poor, and the requirement of realizing temperature measurement of more channels by one system cannot be met.

SUMMERY OF THE UTILITY MODEL

An object of the present invention is to solve at least the above problems and/or disadvantages and to provide at least the advantages which will be described later.

To achieve these objects and other advantages in accordance with the purpose of the invention, there is provided a test system for large area temperature distribution in hypersonic high temperature wind tunnels, comprising:

the measurement and control unit is communicated with the remote upper computer through a network cable and is configured to comprise a measurement and control host, a main control module and a host acquisition module, wherein the main control module and the host acquisition module are arranged in the measurement and control host;

the data acquisition unit is in data communication with the measurement and control host through a cable so as to acquire large-area temperature distribution of the wind tunnel, and is configured to comprise 8 acquisition front ends and thermocouple groups matched with the acquisition front ends;

the main control module is configured to adopt an embedded ARM + FPGA chip, the host acquisition module is configured to adopt four FPGA chips, and the main control module is communicated with the host acquisition module through a matched backboard bus;

each acquisition front end comprises 2 acquisition chips, and each acquisition chip is configured to adopt a 24-bit 8-channel parallel AD acquisition chip to construct a 128-channel test channel with a host acquisition module.

Preferably, the model of the ARM + FPGA chip is configured to adopt a xilinx zynq7020 fully programmable chip, and the model of the FPGA is configured to adopt a xilinx spartan6 series.

Preferably, each acquisition front end is respectively connected with the voltage module and the thermocouple group through a plurality of matched screw terminals;

the inner cavity of each acquisition front end is provided with a matched thermostatic plate, test points for measuring the temperature change of a reference end are arranged on the thermostatic plate, and the reference end of the thermocouple is configured to be connected with the test points;

each acquisition front end is provided with a program control gain amplifier matched with each test channel.

The utility model discloses at least, include following beneficial effect: the technical scheme of the utility model be the temperature measurement who provides a modular temperature measuring device, its temperature measurement through a system realization 128 passageways, the integrated level is high, requires lowly to the application model scope of thermocouple, and modular intensity is high, has miniaturization, low-power consumption, high reliability, characteristics that anti-interference is strong, so it can be applied to in hypersonic speed high temperature wind-tunnel large tracts of land temperature distribution measurement test betterly.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.

Drawings

FIG. 1 is a block diagram of the middle temperature measurement system of the present invention;

FIG. 2 is a schematic diagram of a 16-channel temperature acquisition front-end module of the present invention;

fig. 3 is a schematic block diagram of the 8-channel parallel AD acquisition of the present invention;

FIG. 4 is a component design diagram of the 8-channel parallel A/D acquisition of the present invention;

FIG. 5 is an enlarged schematic view of the left half of FIG. 4;

FIG. 6 is an enlarged view of the right half of FIG. 4;

fig. 7 is a thermostatic plate in the middle temperature acquisition front-end module of the present invention;

fig. 8 is a flowchart of the intermediate temperature signal oversampling technique of the present invention.

Detailed Description

The present invention is further described in detail below with reference to the drawings so that those skilled in the art can implement the invention with reference to the description.

Fig. 1-2 show an implementation form of a test system for large-area temperature distribution of hypersonic high-temperature wind tunnel according to the present invention, which includes:

the system comprises a measurement and control unit which is communicated with a far-end upper computer through a network cable, and is configured to comprise a measurement and control host 1, a main control module 2 and a host acquisition module 3 which are arranged in the measurement and control host, wherein the main control module is inserted into a case of the measurement and control host, an ARM + FPGA embedded hardware design method is adopted, the measurement and control unit is communicated with the host acquisition module through an internally designed backboard bus, the host acquisition module adopts xilinx spartan6 series FPGA hardware, receives A/D converted data sent by a front-end acquisition module, processes and packages the acquired test data and sends the data to the main control module;

the data acquisition unit is configured to comprise 8 acquisition front ends 4 and thermocouple groups (not shown) matched with the acquisition front ends, the temperature acquisition front end module completes parameter configuration of the front end acquisition module, automatically identifies the ID number of the front end acquisition module accessed into the system, and analyzes test data of different temperature acquisition front end modules through the ID number;

the main control module is configured to adopt an embedded ARM + FPGA chip, the host acquisition module is configured to adopt four FPGA chips, and the main control module is communicated with the host acquisition module through a matched backboard bus;

each acquisition front end comprises 2 acquisition chips, each acquisition chip is configured to adopt a 24-bit 8-channel parallel AD acquisition chip, and further a 128-channel test channel is constructed with the host acquisition module, in the scheme, in order to solve the problems of high vacuum, high temperature, strong interference and large-area temperature measurement of the strong polluted environment of the high-temperature wind tunnel, the system of the scheme adopts a distributed architecture design, has the characteristics of miniaturization, low power consumption, high reliability and strong interference resistance, can be applied to the test environment of hypersonic high-temperature wind tunnel with high vacuum, high temperature, strong interference and strong pollution, specifically, the hardware of the measurement and control unit mainly comprises a measurement and control host, and 1 main control module and 4 host acquisition modules which are arranged in the measurement and control host, and the hardware of the data acquisition unit mainly comprises 8 acquisition front ends, wherein each acquisition front end acquires 16 paths of signals and can finish voltage and temperature tests of 128 channels.

The measurement and control host adopts a chassis-type structure, a back board bus and a slot are designed in the measurement and control host, 4 host acquisition modules and 1 main control module are respectively inserted in the measurement and control host, and the main control module adopts ARM + FPGA embedded hardware design; the acquisition front end adopts xilinx spartan6 series FPGA hardware, collects the quantization data that the AD acquisition chip gathered, the test data packing that will gather is sent to host system, every acquisition front end can access two AD acquisition chips, the configuration of AD acquisition chip module parameter is accomplished to the acquisition front end, the acquisition front end ID of automatic identification access sends data to host system, gather the data of front end module through the different temperature of module ID discernment, acquisition module packing data transmission to host system.

The AD acquisition chip is connected with voltage and temperature signals through a screw terminal, a program control gain amplifier is arranged in hardware to finish amplification of signals with different measuring ranges, and a temperature measurement module is arranged in the hardware to finish cold end compensation of thermocouple testing. The AD acquisition chip adopts 2 pieces of 24bit, 8 channels are parallelly realized 16 channels of high-precision voltage, temperature acquisition channels, and the mountable is in the interior cavity of model. After the quantized data codes are collected, the quantized data codes are sent to a collection module of the measurement and control host through a high-speed bus. The temperature acquisition front-end module is connected with the measurement and control host through a cable and transmits the data after A/D quantization to the measurement and control host. The technical indexes of the design of the temperature acquisition front-end module are as follows:

a. collecting a channel: a single module 16 lane, 8 module 128 lanes total;

b. sampling rate: 100, 500, 1000, 2000, 5000 and 10000 points per second, and can be selected in a grading way;

c. data transmission: TCP/IP protocol network transmission;

d. acquisition precision: voltage is 0.5 percent, and temperature is +/-4 ℃;

thermocouple types: b, E, J, K, R, S, T, N.

In another example, the model of the ARM + FPGA chip is configured to adopt a xilinx ZYNQ7020 fully programmable chip, and the model of the FPGA is configured to adopt a xilinx spartan6 series, in this scheme, the model of the ARM + FPGA chip is implemented by adopting a xilinx ZYNQ7020 fully programmable chip, in the ZYNQ7020, the FPGA and the ARM are integrated into one chip, communication between the FPGA and the ARM uses three interfaces of AXI _ HP, AXI _ GP and AXI _ ACP for communication, a bandwidth can reach Gbps, and a problem that communication bandwidth between the FPGA and the ARM is insufficient cannot exist. The main control module utilizes the FPGA core of zynq-7020 to realize the functions of high-speed acquisition, control and logic output with high real-time requirement, the FPGA completes the high-speed acquisition data interaction with 4 acquisition modules, the ARM completes the instruction control and data interaction with the upper computer through the Ethernet, and the system requires high transmission bandwidth and works stably and reliably, so that the model of the FPGA is realized by selecting xilinx spartan6 series FPGA hardware.

As shown in fig. 2 and 7, in another example, each acquisition front end is connected to a voltage module and a thermocouple group through a plurality of screw terminals 5 which are matched with each other, and is used for acquiring a voltage signal and a temperature signal respectively, and the screw terminals are designed so that a line of the device can be connected to an acquisition channel on the acquisition front end rapidly;

the inner cavity of each acquisition front end is provided with a matched thermostatic plate 6 which is used for uniformly dispersing heat generated by the chip so as to ensure the service life of the equipment, test points for measuring the temperature change of the reference end are arranged on the thermostatic plate, and the reference end of the thermocouple is configured to be connected with the test points;

each acquisition front end is provided with a program control gain amplifier matched with each test channel, and the temperature acquisition front end is designed with the program control amplifier to adapt to signal acquisition with different ranges.

A method for applying a large-area temperature distribution test system of a hypersonic high-temperature wind tunnel comprises the following steps:

the thermocouple acquires temperature signals of each measuring point of the temperature measurement model and transmits the temperature signals to each acquisition front end through a cable;

the program control amplifier amplifies the received signals with different measuring ranges and sends the processed signals to corresponding AD acquisition chips;

the AD acquisition chip finishes AD conversion of temperature signals, each acquisition front end adopts an oversampling technology to acquire the temperature signals, the cold end temperature value is obtained by adopting a sliding average method, the acquired temperature signals are processed into temperature data according to the thermocouple type and the cold end temperature value, and a schematic diagram and element connection of an AD acquisition module are shown in FIGS. 3-6;

the front-end acquisition module packs the temperature data based on the ID number of the front-end acquisition module and sends the packed temperature data to the host acquisition module through the high-speed bus;

the host computer acquisition module identifies the received temperature data through the ID number, obtains the corresponding temperature data according to the sampling rate set by the user, and then carries out instruction control and data interaction with the upper computer through the Ethernet. The specific test method for measuring the large-area temperature distribution on the test model is obtained by adopting a temperature test method matched with the system, the type of the applied thermocouple group comprises multiple types of B, E, J, K, R, S, T and N, the problem of large-area temperature distribution measurement in a complicated environment of a hypersonic high-temperature wind tunnel is solved, and reliable test data can be provided for a temperature measurement test and a heat flow measurement test;

the temperature signal oversampling technology is adopted for voltage and temperature signal acquisition, and the oversampling sampling technology is designed to finish voltage and temperature signal acquisition on the basis of the hardware in order to improve the resolution and acquisition precision of the test signal; the continuous analog signals are discretized through the ADC in the signal acquisition process, the number of bits of the ADC is limited to 24 bits, an oversampling technology is applied, the effective number of bits of the ADC can be improved under the hardware condition that the number of bits of the ADC is fixed, resolution and acquisition precision are improved from software at a certain time under the hardware condition, the purpose of improving the resolution of the ADC is achieved, signals received by the cold-end temperature sliding average technology are processed, the algorithm of the sliding average filtering is designed according to the characteristic of the cold-end temperature of data, and jumping of the cold-end temperature signals is eliminated.

In another example, as shown in fig. 7, in the temperature signal oversampling technology, the oversampling frequency is 100000 points/second, the oversampling data is reduced to 10000 points/second by 10-point averaging, the sampling rate of the host acquisition module is graded and selectable by 10000, 5000, 2000, 1000, 500, 200, and 100 points/second, and the noise reduction processing is implemented by the snapshot averaging, in the scheme of the acquisition signal processing, the oversampling of the system is to sample the temperature signal at the highest sampling frequency higher than 10 times. The reason for this is that quantization distortion occurs when an analog signal is converted into a digital signal, and the analog signal needs to be filtered by an analog low-pass filter, but the analog low-pass filter does not directly filter out signals other than the cutoff frequency, but greatly reduces the signals other than the cutoff frequency, and at the same time slightly reduces and affects signals within the cutoff frequency, and if the cutoff frequency of the low-pass filter can be increased, the influence of the analog low-pass filter on the signals in the frequency band expected to be reserved is reduced; the oversampling can push the quantization noise to a higher frequency, and the system can select a low-pass filter with a higher cut-off frequency, thereby avoiding signal aliasing, improving resolution and reducing noise, the temperature acquisition front-end module of the scheme adopts an original sampling rate of 100K, the true sampling rate of 10K is reached through 10 times of oversampling, and the signal-to-noise ratio of the sampling signal and the acquisition precision of the temperature signal are improved through an oversampling technology and a digital filtering technology.

In another example, the moving average filtering technique is to establish a data buffer in each acquisition front-end buffer, and acquire N data samples and store the data samples in the buffer; when new data (N +1 point) is collected, the 1 st point in the original buffer area is removed, and the data of the 2 nd, 3 rd, 4 th and … th points in the original buffer area are sequentially moved to the 1 st, 2 nd, 3 th and … th N-1 point positions. And calculating the arithmetic mean value T _ mean of N data (2,3,4 … N +1) including the newly acquired data as the cold end temperature data at the moment, and writing the T _ mean value into the Nth point position of the buffer area. By adopting the data after the sliding average, signal interference is filtered, and sudden change of cold end temperature data is avoided. Therefore, a new average value can be calculated every time sampling is carried out, so that the data processing speed is increased, and the jump of the cold end temperature is eliminated. The reason is that in the temperature testing process, complex interference signals can exist on the site, the sudden change of the cold end temperature is caused by site interference, the jump of the cold end causes fluctuation, jitter and instability of the whole temperature test, and the test result is influenced.

A50-point moving average filtering algorithm is selected through a field test moving average filtering algorithm, the algorithm is realized in FPGA hardware, and after long-time test verification is carried out, the problems of jumping and mutation are solved through temperature test after the algorithm is applied.

The above scheme is merely illustrative of a preferred example, and is not limiting. When the utility model is implemented, the proper replacement and/or modification can be carried out according to the requirements of users.

The number of apparatuses and the scale of the process described here are intended to simplify the description of the present invention. Applications, modifications and variations of the present invention will be apparent to those skilled in the art.

While embodiments of the invention have been disclosed above, it is not intended to be limited to the applications listed in the specification and the examples. It can be applicable to various and be fit for the utility model discloses a field completely. Additional modifications will readily occur to those skilled in the art. The invention is therefore not to be limited to the specific details and illustrations shown and described herein, without departing from the general concept defined by the claims and their equivalents.

Claims (3)

1. A test system for large-area temperature distribution of a hypersonic high-temperature wind tunnel is characterized by comprising:

the measurement and control unit is communicated with the remote upper computer through a network cable and is configured to comprise a measurement and control host, and a main control module and a host acquisition module which are arranged in the measurement and control host;

the data acquisition unit is in data communication with the measurement and control host through a cable so as to acquire large-area temperature distribution of the wind tunnel, and is configured to comprise 8 acquisition front ends and thermocouple groups matched with the acquisition front ends;

the main control module is configured to adopt an embedded ARM + FPGA chip, the host acquisition module is configured to adopt four FPGA chips, and the main control module is communicated with the host acquisition module through a matched backboard bus;

each acquisition front end comprises 2 acquisition chips, and each acquisition chip is configured to adopt a 24-bit 8-channel parallel AD acquisition chip to construct a 128-channel test channel with a host acquisition module.

2. The test system for hypersonic high temperature wind tunnel large area temperature distribution of claim 1, wherein said ARM + FPGA chip is configured as a xilinx zynq7020 fully programmable chip, and said FPGA is configured as a xilinx spartan6 series.

3. The system for testing the large-area temperature distribution of the hypersonic-velocity high-temperature wind tunnel according to claim 1, wherein each acquisition front end is respectively connected with the voltage module and the thermocouple group through a plurality of matched screw terminals;

the inner cavity of each acquisition front end is provided with a matched thermostatic plate, test points for measuring the temperature change of a reference end are arranged on the thermostatic plate, and the reference end of the thermocouple is configured to be connected with the test points;

each acquisition front end is provided with a program control gain amplifier matched with each test channel.

Images