In-situ testing system for temperature of flow distribution pair of axial piston pump based on two-dimensional interpolation inversion

Abstract

The application discloses an axial plunger pump flow distribution pair temperature in-situ testing system based on two-dimensional interpolation inversion, which comprises a hardware subsystem and a software subsystem, and the hardware subsystem and the software subsystem communicate through a serial port; the hardware subsystem is used for collecting sensor signals; the software subsystem comprises a basic configuration module, which is used for setting basic parameters and transmitting the sensor signals to a channel selection module by using the basic parameters; the channel selection module is used for selecting channels required for collecting the sensor signals and connecting a data acquisition control module; the data acquisition control module is used for controlling the software subsystem; an oil film temperature centralized display module is used for analyzing the sensor signals into temperature data and performing real-time display; an oil film temperature measuring point phase information distribution module is used for displaying the temperature data at corresponding phases; and an oil film temperature field distribution cloud picture module is used for inverting the temperature data, obtaining a matrix of the flow distribution disc temperature field and performing cloud picture display.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of hydraulic system oil film test and two-dimensional interpolation algorithm, and particularly relates to an axial piston pump flow distribution pair temperature in-situ test system based on two-dimensional interpolation inversion. BACKGROUND

[0002] The axial piston pump is a core power element of a hydraulic system, and is widely applied to engineering machinery and aerospace fields due to its compact structure, large output power and large power density. The flow distribution pair is one of three key friction pairs of the axial piston pump, and the higher the temperature of the flow distribution pair is, the lower the viscosity value of the oil is, and then the larger the leakage flow loss and viscous friction loss of the flow distribution pair are, and the more serious the heat generation is. Meanwhile, the temperature change will cause thermal expansion deformation between the flow distribution disc and the cylinder wall surface material, so that the oil film property is changed, and the friction is more likely to occur at the position, and the phenomena such as wear or disc burning often occur in engineering.

[0003] In the existing field of hydraulic system oil film test, the research on temperature signal collection only stays in the realization of basic functions such as signal collection, data change with time, data saving and the like. The inversion of temperature data cannot be realized by combining the phase of the measuring point and the related algorithm, and the result display of the entire temperature field cannot be realized.

[0004] Therefore, for the field of hydraulic system test, it is necessary to study the inversion from discrete data to the entire field data. Taking temperature test as an example, the two-dimensional structure of time-measuring point data is expanded to the three-dimensional structure of time-phase information-measuring point data, the change of the entire temperature field data can be monitored in real time, the position of the temperature abnormal point can be directly seen, and data support can be provided for subsequent related material improvement and structure optimization. Therefore, the axial piston pump flow distribution pair temperature in-situ test system based on two-dimensional interpolation inversion is urgently needed to solve the problems in the prior art. SUMMARY

[0005] The axial piston pump flow distribution pair temperature in-situ test system based on two-dimensional interpolation inversion is provided, and the real-time display of the axial piston pump oil film temperature field data is realized through the interface with Matlab in the Labview development environment.

[0006] To achieve the above object, the axial piston pump flow distribution pair temperature in-situ test system based on two-dimensional interpolation inversion is provided, which comprises a hardware subsystem and a software subsystem, and the hardware subsystem and the software subsystem communicate through a serial port.

[0007] The hardware subsystem is used for collecting sensor signals.

[0008] The software subsystem includes a basic configuration module, a channel selection module, a data acquisition and control module, a centralized display module for oil film temperature, a phase information distribution module for oil film temperature measurement points, and a cloud map module for oil film temperature field distribution. It is used to complete the in-situ temperature test of the axial piston pump distribution pair based on two-dimensional interpolation inversion.

[0009] The basic configuration module is used to set basic parameters and use the basic parameters to transmit the sensor signal to the channel selection module;

[0010] The channel selection module is used to select the channel from which the sensor signal needs to be acquired, and is connected to the data acquisition control module.

[0011] The data acquisition and control module is used to control the software subsystem, and the output terminal of the data acquisition module is respectively connected to the oil film temperature centralized display module, the oil film temperature measuring point phase information distribution module and the oil film temperature field distribution cloud map module;

[0012] The oil film temperature centralized display module is used to parse the sensor signal into temperature data and display it in real time;

[0013] The oil film temperature measuring point phase information distribution module is used to display the temperature data at the corresponding phase.

[0014] The oil film temperature field distribution cloud map module is used to invert the temperature data, obtain the matrix of the distribution plate temperature field, and display it as a cloud map.

[0015] Optionally, the hardware subsystem includes a temperature sensor and a data acquisition card. The temperature sensor is mounted on the axial piston pump distribution plate and connected to the data acquisition card via a cable.

[0016] The temperature sensor is used to measure the oil film temperature of the axial piston pump distribution plate and acquire sensor signals.

[0017] The acquisition card is used to acquire the sensor signals.

[0018] Optionally, the software subsystem is developed using LabVIEW software on a host computer.

[0019] Optionally, the basic parameters include serial port number, baud rate, data storage path, and the maximum and minimum values ​​of the sensor temperature range.

[0020] Optionally, the basic configuration module includes a VISA configuration serial port unit, a VISA write unit, a VISA read unit, and a VISA close unit, which are connected in sequence;

[0021] The VISA configuration serial port unit is used to initialize data transmission settings based on the serial port number and the baud rate;

[0022] The VISA writing unit is used to send a command to the acquisition card to acquire the oil film temperature;

[0023] The VISA reading unit is used to read the sensor signal and prepare for parsing;

[0024] The VISA closing unit is used to terminate the reading process and release the occupied resources.

[0025] Optionally, the channel selection module includes a checkmark Boolean unit and a dial display unit, and the output of the checkmark Boolean unit is connected to the dial display unit.

[0026] The checkmark Boolean unit is used to control the number of measurement points that need to collect the sensor signal and to collect data from the selected measurement points.

[0027] The dial-type display unit is used to count the number of selected measurement points that need to collect the sensor signals.

[0028] Optionally, the data acquisition and control module includes a condition structure unit, a Boolean unit, an elapsed time unit, and a display unit, which are connected in sequence;

[0029] The conditional structure unit is used to determine whether data correction is needed;

[0030] The Boolean unit is used to control the start and stop of the software subsystem's shutdown, data correction, data acquisition, and data saving.

[0031] The used time unit is used to record the time taken since the start of the operation of the software subsystem;

[0032] The display unit is used to display the elapsed time.

[0033] Optionally, the oil film temperature centralized display module includes a flat sequential structure unit, a string truncation unit, a string connection unit, and a waveform chart unit, which are connected in sequence;

[0034] The tiling sequence structure unit is used to collect sensor signals from several of the acquisition cards in a predetermined order;

[0035] The string interception unit is used to intercept, verify, and parse the sensor signals sent by the acquisition card;

[0036] The connection string unit is used to reassemble the intercepted sensor signals to generate a check code and compare it with the check code in the original data.

[0037] The waveform chart unit is used to display the temperature data.

[0038] Optionally, the oil film temperature measuring point phase information distribution module includes a tab control unit and a numerical control unit;

[0039] The tab control unit is used to overlay the oil film temperature centralized display module and the oil film temperature measuring point phase information distribution module to obtain temperature values ​​and transmit them to the numerical control module.

[0040] The numerical control unit is used to display the temperature value.

[0041] Optionally, the oil film temperature field distribution cloud map module includes MATLAB script formula node units and three-dimensional surface units;

[0042] The MATLAB script formula node unit is used to write two-dimensional interpolation algorithm code for the temperature data, obtain the matrix of the temperature field of the distribution disk, and transmit it to the three-dimensional surface unit.

[0043] The three-dimensional curved surface unit is used to display the matrix of the temperature field of the distribution plate in three dimensions.

[0044] This invention has the following beneficial effects: It provides a new research method for the application of two-dimensional interpolation algorithms in data acquisition, offers researchers visualization of data acquisition results, enables real-time monitoring of the data acquisition process, and facilitates the elimination of anomalies that may occur during the acquisition process. The specific advantages and positive effects of this invention are as follows:

[0045] (1) Using the LabVIEW development environment, a data acquisition program is written, which integrates basic configuration, channel selection, data correction, data inversion and data saving. This not only enables the smooth acquisition of data, but also allows for real-time monitoring of any abnormal situations that occur during the process. Researchers can modify the required basic parameters according to their own acquisition equipment and modify the interpolation program to achieve the acquisition and inversion of relevant data.

[0046] (2) LabVIEW has some limitations when it comes to interpolation algorithms. LabVIEW's interpolation algorithms are implemented graphically, but their applicability is narrow and they require configuring multiple basic modules, which can make operation cumbersome. In contrast, Matlab software provides a convenient and fast m-language programming environment, making it easier to write and execute custom interpolation algorithms. By writing a two-dimensional inversion program in the Matlab environment and passing it to the Matlab software embedded in LabVIEW for execution, the advantages of both LabVIEW and Matlab software can be fully utilized, resulting in better applicability and efficiency of the acquisition program and simplifying the development process. Attached Figure Description

[0047] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0048] Figure 1 This is a structural diagram of the in-situ temperature testing system for the axial piston pump distribution pair based on two-dimensional interpolation inversion, according to an embodiment of the present invention.

[0049] Figure 2 This is a schematic diagram of the phase information distribution proposed in an embodiment of the present invention;

[0050] Figure 3 This is a flowchart of the LabVIEW-Matlab two-dimensional interpolation algorithm proposed in an embodiment of the present invention;

[0051] Figure 4 This is a schematic diagram of the inversion algorithm results proposed in this embodiment of the invention;

[0052] Figure 5 This is a flowchart illustrating the data correction process proposed in an embodiment of the present invention. Detailed Implementation

[0053] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present application will now be described in detail with reference to the accompanying drawings and embodiments.

[0054] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0055] LabVIEW software is the most representative graphical programming development platform in the field of virtual instrumentation and is one of the most widely used data acquisition and control development environments internationally. Compared to traditional programming software, LabVIEW uses a graphical programming language, targeting test engineers rather than professional programmers, making programming more convenient and offering a more user-friendly interface. Furthermore, corresponding interfaces can be developed in LabVIEW for different acquisition devices, demonstrating excellent adaptability. It can also interact with languages ​​such as M-language and C++ through the use of dynamic link libraries, exhibiting excellent compatibility.

[0056] like Figure 1 As shown, this embodiment provides an in-situ temperature testing system for the axial piston pump distribution plate based on two-dimensional interpolation inversion. It mainly consists of a hardware system and a software system. The hardware system comprises the axial piston pump distribution plate, a temperature sensor, and a data acquisition card. The temperature sensor is installed at a temperature port on the axial piston pump distribution plate. The temperature sensor and the data acquisition card are connected by a cable. The temperature sensor measures the temperature of the axial piston pump distribution plate, and the data acquisition card acquires the sensor signal and transmits it to the software system. Furthermore, the temperature sensor is a thermocouple temperature sensor, and the data acquisition card is a RS-485 signal acquisition card.

[0057] The software system is an in-situ temperature testing system developed using LabVIEW software on a host computer. All modules in the software system are developed within the LabVIEW programming environment, and mainly include a basic configuration module, a channel selection module, a centralized oil film temperature display module, an oil film temperature measurement point phase information distribution module, an oil film temperature field distribution cloud map module, and a data acquisition and control module. The host computer communicates with the hardware system via a serial port.

[0058] The basic configuration module is used to establish the interface between the 485 temperature signal and the LabVIEW acquisition program, mainly setting the basic parameters of the acquisition device. It includes a VISA serial port configuration module (initializing data transmission according to the specified serial port number and baud rate), a VISA write module (sending acquisition data commands to the acquisition card), a VISA read module (reading data sent from the acquisition card and preparing for parsing), and a VISA close module (ending the entire reading process and releasing occupied resources). These modules are connected sequentially. The configured parameters mainly include the serial port number, baud rate, file save location (or data save path), and the maximum and minimum values ​​of the sensor temperature range. Since there are 28 measurement points, and each acquisition device has a maximum of 16 channels, two different addresses need to be defined in the VISA read module for communication between the two acquisition devices.

[0059] The channel selection module is used to select the channels from the 28 channels for which data should be collected. It primarily sets the number of channels out of the total 28 channels that will be used for data acquisition. It mainly includes 28 checkmark Boolean modules (controlling the number of measurement points for which data should be collected; a checkmark indicates selection, meaning data will be collected from that measurement point), and one dial-style display module (counting the number of selected measurement points). Each of the 28 checkmark Boolean modules is connected to a condition module (outputting 1 when a checkmark Boolean module is selected and 0 when it is not selected). The 28 condition modules are used to generate a one-dimensional array. The one-dimensional array is searched for by a search module to count the number of elements with the value 1, and the result is output to the dial-style display module.

[0060] The oil film temperature centralized display module is used to parse the digital values ​​of the acquired data register into temperature data and display it in real time, mainly displaying the acquired data in a two-dimensional coordinate format. It mainly includes a tiled sequential structure module, a string extraction module, a string concatenation module, and a waveform chart module, which are connected sequentially.

[0061] The tiling sequential structure module requires two acquisition cards to collect 28 sets of temperature data because the maximum number of channels that a single acquisition card can collect is 16. The tiling sequential structure first collects data from acquisition card 1, and then collects data from acquisition card 2. The string truncation module truncates, verifies, and parses the data sent from the acquisition cards. The string concatenation module reassembles the truncated data to generate a checksum, which is then compared with the checksum in the original data. The waveform graph module displays the temperature data.

[0062] First, the integrity of the data length needs to be checked. If the data packet is incomplete, the data will not be parsed. Temperature data is parsed according to the following formula:

[0063]

[0064] Where n is the digital value of the acquired data register, and T max T is the maximum range of the temperature sensor. min T is the minimum value of the temperature sensor's range. n Let n be the sensor temperature value corresponding to n.

[0065] The oil film temperature measuring point phase information distribution module displays the parsed data from 28 temperature sensors at the corresponding phase positions. Essentially, it combines the measuring point temperature with the specific coordinates of each measuring point, providing a clear view of the measuring point's location and corresponding temperature. It mainly includes a tab control module and a numerical control module. The tab control module overlays the oil film temperature centralized display module with the oil film temperature measuring point phase information distribution module, allowing switching via mouse and saving page space. The numerical control module displays the specific temperature values. In this embodiment, the distribution plate cross-section is used as the background for the temperature data display, making it easy to locate the measuring points. Figure 2 As shown.

[0066] The oil film temperature field distribution cloud map module is used to invert the temperature field data of the entire distribution sub-channel from the 28 sets of temperature data obtained through analysis and display it as a cloud map. Specifically, it takes the temperature data transmitted from the acquisition device to the host computer, the planar position of each measuring point, and combines it with a two-dimensional interpolation algorithm written in the Matlab environment to invert the temperature field data and display it in the form of a coordinate cloud map. It mainly includes a MATLAB script formula node module and a 3D surface module. The MATLAB script formula node module has a built-in interface for communication with MATLAB; placing code into the formula node is equivalent to running the code in MATLAB. The 3D surface module displays the code execution results in a three-dimensional form. The formula node has three outputs: x, y, and z matrices. These three matrices are connected to the corresponding positions in the 3D surface module to complete the data transfer. The inversion process is as follows: Figure 3 As shown, 28 sets of temperature sensor data are passed as parameters into the MATLAB script formula node. Two-dimensional interpolation algorithm code is written in the MATLAB script formula node to invert the X, Y and T matrices of the temperature field of the entire distribution plate. Finally, the coordinate matrix is ​​passed into the three-dimensional surface module for real-time display.

[0067] The two-dimensional interpolation algorithm is based on the biotone spline interpolation of the Green's function. The algorithm idea is as follows:

[0068] Suppose a surface has n known points, the node requiring interpolation is p0, and the number of points closest to p0 is k. The distance from point p0 to the known points is:

[0069] r 0i =|x i -x0|, i = 1, 2, ..., n

[0070] Where, r 0i Let p0 be the distance from the i-th point, and x0 be the x-coordinate of p0. iGiven the coordinates of the i-th known data point, sort all distances in ascending order using a sorting algorithm. After sorting, the coordinates of the first k points are (x, y, y). i ,y i ,z i ), i = 1, 2, 3, ..., k.

[0071] Let the coordinate matrix X = [x1, x2, ..., x k ], Y = [y1, y2, ..., y k The temperature matrix Z = [z1, z2, ..., z] k The k×k Green's matrix is:

[0072]

[0073] Where, d ij It is obtained by using the bitone Green's function as the basis function.

[0074]

[0075] in,

[0076] Based on the Green's matrix G and the temperature matrix Z, the weight matrix W can be calculated using the following formula:

[0077] W=G -1 Z

[0078] This leads to the 1×k order Green's function matrix G. p :

[0079] G p =[d 01 ,d 02 …d 0k ]

[0080] Then the temperature value z at point p0 p The calculation formula is:

[0081] z p =G p W

[0082] The inversion results of the temperature field of the distribution auxiliary oil film are as follows: Figure 4 As shown.

[0083] The data acquisition and control module is used for data correction, overall program operation and shutdown control, data saving and shutdown control, and recording program execution time. Essentially, it controls the entire system, including the start and end of data correction, data saving, and program execution. It mainly includes a conditional structure module, a Boolean module, an elapsed time module, and a display module.

[0084] The condition structure module determines whether data correction is needed. If correction is required, it uses calibrated sensor data as a baseline to correct other sensors. If correction is not needed, the sensor data is not corrected, and the next step is performed directly. The Boolean module controls the start and stop of the in-situ temperature testing system's shutdown, data correction, data acquisition, and data saving. The elapsed time module records the time elapsed since the in-situ temperature testing system began operation; the display module displays the elapsed time in seconds.

[0085] The data is saved in .tdms and .txt formats.

[0086] Data correction process as follows Figure 5 As shown, the advantage lies in eliminating differences in temperature sensor readings caused by installation errors. The specific steps are as follows:

[0087] Before the plunger pump is running, assuming no corrections are made, there are different temperature differences between the 1 set of uncalibrated sensors and the other 27 sets of uncalibrated sensors, which can be calculated by the following formula:

[0088] ΔT=T 修正已标定 -T 修正未标定

[0089] Where ΔT is the difference between the temperature readings of the calibrated and uncalibrated sensors before correction, T 修正已标定 To correct the previously calibrated sensor temperature reading, T 修正未标定 This is to correct the previously uncalibrated sensor temperature readings.

[0090] Therefore, during the testing phase, the final temperature data is as follows:

[0091] T end =T 测试未标定 +ΔT

[0092] Among them, T end This indicates the final temperature reading of the uncalibrated sensor, T. 测试未标定 This indicates the sensor reading that was not calibrated during the formal temperature test.

[0093] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An in-situ temperature testing system for the distribution pair of an axial piston pump based on two-dimensional interpolation inversion, characterized in that, It includes a hardware subsystem and a software subsystem, and the hardware subsystem and the software subsystem communicate via a serial port; The hardware subsystem is used to acquire sensor signals; The software subsystem includes a basic configuration module, a channel selection module, a data acquisition and control module, a centralized display module for oil film temperature, a phase information distribution module for oil film temperature measurement points, and a cloud map module for oil film temperature field distribution. It is used to complete the in-situ temperature test of the axial piston pump distribution pair based on two-dimensional interpolation inversion. The basic configuration module is used to set basic parameters and use the basic parameters to transmit the sensor signal to the channel selection module; The channel selection module is used to select the channel from which the sensor signal needs to be acquired, and is connected to the data acquisition control module. The data acquisition and control module is used to control the software subsystem, and the output terminal of the data acquisition module is respectively connected to the oil film temperature centralized display module, the oil film temperature measuring point phase information distribution module and the oil film temperature field distribution cloud map module; The oil film temperature centralized display module is used to parse the sensor signal into temperature data and display it in real time; The oil film temperature measuring point phase information distribution module is used to display the temperature data at the corresponding phase. The oil film temperature field distribution cloud map module is used to invert the temperature data, obtain the matrix of the distribution plate temperature field, and display it as a cloud map.

2. The in-situ temperature testing system for the axial piston pump distribution pair based on two-dimensional interpolation inversion as described in claim 1, characterized in that, The hardware subsystem includes a temperature sensor and a data acquisition card. The temperature sensor is installed on the axial piston pump distribution plate and is connected to the data acquisition card via a cable. The temperature sensor is used to measure the oil film temperature of the axial piston pump distribution plate and acquire sensor signals. The acquisition card is used to acquire the sensor signals.

3. The in-situ temperature testing system for the axial piston pump distribution pair based on two-dimensional interpolation inversion as described in claim 1, characterized in that, The software subsystem was developed using LabVIEW software on a host computer.

4. The in-situ temperature testing system for the axial piston pump distribution pair based on two-dimensional interpolation inversion as described in claim 2, characterized in that, The basic parameters include serial port number, baud rate, data storage path, and the maximum and minimum values ​​of the sensor temperature range.

5. The in-situ temperature testing system for the axial piston pump distribution pair based on two-dimensional interpolation inversion as described in claim 4, characterized in that, The basic configuration module includes a VISA configuration serial port unit, a VISA write unit, a VISA read unit, and a VISA close unit, which are connected in sequence; The VISA configuration serial port unit is used to initialize data transmission settings based on the serial port number and the baud rate; The VISA writing unit is used to send a command to the acquisition card to acquire the oil film temperature; The VISA reading unit is used to read the sensor signal and prepare for parsing; The VISA closing unit is used to terminate the reading process and release the occupied resources.

6. The in-situ temperature testing system for the axial piston pump distribution pair based on two-dimensional interpolation inversion as described in claim 1, characterized in that, The channel selection module includes a checkmark Boolean unit and a dial display unit, and the output of the checkmark Boolean unit is connected to the dial display unit. The checkmark Boolean unit is used to control the number of measurement points that need to collect the sensor signal and to collect data from the selected measurement points. The dial-type display unit is used to count the number of selected measurement points that need to collect the sensor signals.

7. The in-situ temperature testing system for the axial piston pump distribution pair based on two-dimensional interpolation inversion as described in claim 1, characterized in that, The data acquisition and control module includes a condition structure unit, a Boolean unit, an elapsed time unit, and a display unit, which are connected in sequence. The conditional structure unit is used to determine whether data correction is needed; The Boolean unit is used to control the start and stop of the software subsystem's shutdown, data correction, data acquisition, and data saving. The used time unit is used to record the time taken since the start of the operation of the software subsystem; The display unit is used to display the elapsed time.

8. The in-situ temperature testing system for the axial piston pump distribution pair based on two-dimensional interpolation inversion as described in claim 2, characterized in that, The oil film temperature centralized display module includes a sequential structure unit when the film is laid out, a string truncation unit, a string connection unit, and a waveform chart unit, which are connected in sequence. The tiling sequence structure unit is used to collect sensor signals from several of the acquisition cards in a predetermined order; The string interception unit is used to intercept, verify, and parse the sensor signals sent by the acquisition card; The connection string unit is used to reassemble the intercepted sensor signals to generate a check code and compare it with the check code in the original data. The waveform chart unit is used to display the temperature data.

9. The in-situ temperature testing system for the axial piston pump distribution pair based on two-dimensional interpolation inversion as described in claim 1, characterized in that, The oil film temperature measuring point phase information distribution module includes a tab control unit and a numerical control unit; The tab control unit is used to overlay the oil film temperature centralized display module and the oil film temperature measuring point phase information distribution module to obtain temperature values ​​and transmit them to the numerical control module. The numerical control unit is used to display the temperature value.

10. The in-situ temperature testing system for the axial piston pump distribution pair based on two-dimensional interpolation inversion as described in claim 1, characterized in that, The oil film temperature field distribution cloud map module includes MATLAB script formula node units and three-dimensional surface units; The MATLAB script formula node unit is used to write two-dimensional interpolation algorithm code for the temperature data, obtain the matrix of the temperature field of the distribution disk, and transmit it to the three-dimensional surface unit. The three-dimensional curved surface unit is used to display the matrix of the temperature field of the distribution plate in three dimensions.

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