A wireless strain acquisition system packaged in a tracked driving structure and a calibration method thereof

Abstract

The present application belongs to the field of load monitoring, and particularly relates to a track ring load monitoring of a track driving structure of a coal mine tunneling robot, solves the problem that the cyclic load in the track driving structure is difficult to monitor, designs a wireless strain collection system encapsulated in the track driving structure, and provides a calibration method; the wireless strain collection system comprises a collection card encapsulation body, a battery module, an encapsulation structure, a signal receiving module and an upper computer; the collection card encapsulation body comprises a strain collection module, a signal transmitting module and an epoxy resin body, and can simultaneously complete strain collection in four directions of a track plate; two pairs of strain gauges are symmetrically arranged on a sample plate, strain data obtained by a DH5902N firm data collection system is taken as a standard, through combination of simulation and test, a polynomial curve fitting method is used to calibrate the sensitivity of four channels in the collection card encapsulation body; and the present application realizes multi-degree-of-freedom cyclic load strain data collection of the track plate.

Description

Technical Field

[0001] This invention pertains to the field of load monitoring, specifically to the load monitoring of track rings in the tracked structure of a coal mine tunneling robot. A wireless strain acquisition system encapsulated in the tracked structure is designed, and a calibration method is provided. Background Technology

[0002] The tracked travel structure is a crucial component of coal mine tunneling robots. Operating in confined environments characterized by high impact, collisions, high humidity, and complex coal and rock bottom conditions, it demands high reliability and applicability. A failure in the tracked travel structure means the entire machine cannot continue operating. These failures are often related to fatigue failure of the track plates or breakage of the pins. Real-time monitoring of the cyclic dynamic load changes in the tracked travel structure helps improve the safe and healthy operation of coal mine tunneling robots, preventing unexpected downtime and serious accidents.

[0003] Existing track-embedded patents mostly modify the track plate structure by slotting the inside of the thickened track plate to embed the entire sensing system within the track plate. However, this method is limited by the track plate structure and cannot be applied to many types of track plates. At the same time, slotting inside the steel track plate causes damage to the track plate structure, which seriously affects the service life of the steel track plate.

[0004] How to design a system that can accurately collect real-time data on the cyclic dynamic load changes of the track plates under harsh underground working conditions without compromising the strength of the track plate structure is a problem that current tracked running structures need to solve. Summary of the Invention

[0005] To address the difficulty in acquiring strain data from track plates in tracked structures, this invention aims to provide a wireless strain acquisition system encapsulated within the tracked structure, along with a calibration method. The strain measurement circuit is bonded to the measured location on the track plate for testing the applied strain. The acquisition card package and battery module are integrated into the package structure and installed on the track plate under test, enabling real-time measurement and wireless transmission of cyclic loads on the track plate. Using the DH5902N rugged data acquisition system as a standard, polynomial curve fitting is employed to calibrate the strain acquisition card.

[0006] The wireless strain acquisition system includes a data acquisition card package, a battery module, a package structure, a signal receiving module, and a host computer. The data acquisition card package and the battery module are built into the package structure. The signal receiving module is connected to the host computer via a USB interface. The signal receiving module is responsible for receiving the signals transmitted wirelessly from the data acquisition card package, while the host computer is responsible for storing and processing the signals.

[0007] The data acquisition card package consists of three parts: a strain acquisition module, a signal transmission module, and an epoxy resin body. Strain gauges are attached to the track plate under test, and the pins of the strain gauges are connected to the strain acquisition module, which is responsible for acquiring strain changes. The strain acquisition module and the signal transmission module are integrated on a single PCB board, and the signal transmission module is responsible for transmitting the strain signal acquired by the strain acquisition module. The strain acquisition module and the signal transmission module are sealed with an insulating epoxy resin body to prevent dust and water damage.

[0008] The encapsulation structure includes an encapsulation shell and a shock-absorbing plate; the encapsulation shell is made of metal, specifically Q345, and the shock-absorbing plate is made of nylon; the acquisition card encapsulation and the battery module are placed in two mounting slots in the encapsulation shell, connected by a cable, with the battery module providing power to the acquisition card encapsulation; the wireless strain acquisition system structure, along the direction away from the track ring, includes the track plate under test, the shock-absorbing plate, and the encapsulation shell, connected sequentially by bolts; the track link is fixed to the track plate under test on the side away from the shock-absorbing plate by bolts; the signal receiving module draws power directly from the host computer via a USB interface.

[0009] Heat dissipation silicone pads are first placed around the two mounting slots of the package shell and at the bottom. Then, the data acquisition card package and the battery module are placed in the mounting slots to achieve heat dissipation and shock absorption.

[0010] Four heat dissipation holes are provided on both sides of the package shell for heat dissipation of the data acquisition card package and the battery module; a rectangular groove is provided on the side of the package shell near the shock absorption plate for installing a rectangular sealing ring to achieve waterproof and dustproof sealing; a through hole is provided on the shock absorption plate near the data acquisition card package for connecting the data acquisition card package and the metal strain gauge lead wire; an annular groove is machined around the through hole on the side of the track plate under test, and an O-ring is installed on it to achieve waterproof and dustproof sealing; the metal strain gauge is directly bonded to the track plate under test.

[0011] A strain calibration method, based on the strain acquisition system, comprises the following steps: S1: Perform 1:1 3D modeling of the test bench and the specimen plate, import the 3D model into Workbench for simulation, find two sets of symmetrical positions on the specimen plate, and require that the strain values ​​of each set of symmetrical positions are the same, denoted as A and a and B and b respectively. S2: Based on the location found in the simulation, attach the strain gauge to the corresponding position on the specimen plate, and apply an external force to the specimen plate with the same magnitude as that at the simulation position; use two channels of the DH5902N rugged data acquisition system to measure the strain at positions A and B respectively, and use two channels 1 and 2 of the strain acquisition card to measure the strain at positions a and b. S3: Perform polynomial curve fitting on the two sets of data corresponding to the above measurements (i.e., A and a, B and b) respectively, find the corresponding relationship, determine the sensitivity coefficient of the strain acquisition card, and complete the calibration of the two channels 1 and 2 of the strain acquisition card. S4: Following the calibration methods for channels 1 and 2 described above, complete the calibration of channels 3 and 4; S5: Test the calibrated strain acquisition card to verify the accuracy of the calibration.

[0012] The calibration device has 11 through holes on the sample plate. The central through hole is called the load hole. The hook screw is fixed to the sample plate by two nuts. Two different weights are suspended by the hook screw, so that different strains are generated at the strain gauge attachment point on the sample plate. The remaining 10 through holes on the sample plate form 5 sets of positioning holes, which are fixed to the mounting hole position on the stand by bolts. When the same weight is suspended by the hook screw, by adjusting the combination of the five sets of positioning holes and mounting holes, five sets of strain data can be generated at the strain gauge attachment point. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the working principle of this invention patent; Figure 2 This is an exploded view of the strain acquisition system for the track plate under test in this embodiment; Figure 3 This is a diagram of the data acquisition card package assembly according to an embodiment; Figure 4 This is a diagram of the packaging structure combination of an embodiment; Figure 5 This is an exploded view of the test stand and sample plate in the embodiment; Figure 6 This is a flowchart of the strain acquisition card calibration process in an embodiment; Figure 7 This is a graph showing the data fitting effect between the strain gauge acquisition card and the DH5902N rugged data acquisition system; Figure 8 This is a diagram showing the data verification effect after the strain acquisition card was calibrated; In the diagram: 1-Acquisition card package; 2-Battery module; 3-Packaging structure; 4-Signal receiving module; 5-Host computer; 6-Strain acquisition module; 7-Signal transmitting module; 8-Epoxy resin body; 9-Test track plate; 10-Packaging shell; 10.1-Mounting groove; 10.2-Heat dissipation hole; 10.3-Rectangular groove; 11-Shock damping plate; 11.1-Through hole; 11.2-Annular groove; 12-Chain link; 13-Silicone pad; 14-Rectangular sealing ring; 15-O-ring seal; 16-Bench; 16.1-Mounting hole; 17-Sample plate; 17.1-Load hole; 17.2-Positioning hole; 18-Hook screw; 19-Nut. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] It should be noted that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention. It should be noted that in this specification, relational terms such as "first" and "second" are only used to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0017] Example: 1. Wireless strain acquisition system encapsulated in tracked running structure like Figure 1 As shown, a wireless strain acquisition system encapsulated in a tracked vehicle structure includes a data acquisition card package 1, a battery module 2, an encapsulation structure 3, a signal receiving module 4, and a host computer 5; the data acquisition card package includes a strain acquisition module 6, a signal transmitting module 7, and an epoxy resin body 8, such as... Figure 3 As shown; the acquisition card package 1 and the battery module 2 are built into the package structure 3. The signal receiving module 4 is connected to the host computer 5 through the USB interface. The signal receiving module 4 is responsible for receiving the signal transmitted wirelessly from the acquisition card package 1, and the host computer 5 is responsible for the storage and processing of the signal.

[0018] like Figure 2As shown, the acquisition card package 1 and the battery module 2 are respectively placed in the two mounting slots 10.1 of the package shell 10, and connected by a cable in the middle. The battery module 2 is responsible for powering the acquisition card package 1. The structure of the wireless strain acquisition system includes the track plate under test 9, the shock absorber 11 and the package shell 10 in sequence along the direction away from the track ring, and is connected in sequence by bolts. The track link 12 is fixed to the other side of the track plate under test 9 away from the shock absorber 11 by bolts.

[0019] like Figure 4 As shown, the encapsulation structure 3 includes an encapsulation shell 10 and a shock-absorbing plate 11; the encapsulation shell 10 is made of metal, specifically Q345, and the shock-absorbing plate 11 is made of nylon.

[0020] The embodiment is a four-channel strain data acquisition scheme. In this embodiment, the strain gauge is pasted onto the track plate and connected to the acquisition card package 1 to form a closed loop, realizing the acquisition of multi-degree-of-freedom strain data of the track plate 9 under test. The surface of the strain gauge is coated with an insulating layer for protection. The strain acquisition module 6 amplifies the acquired data and performs A / D conversion, and then sends the strain data to the host computer 5 through the signal transmission module 7. The signal receiving module 4 draws power directly from the host computer 5 through the USB interface.

[0021] Considering heat dissipation characteristics, heat dissipation silicone pads 13 are first arranged around and at the bottom of the two mounting slots 10.1 of the encapsulation shell 10, and then the acquisition card package 1 and the battery module 2 are placed in the mounting slots 10.1 respectively to achieve heat dissipation and shock absorption. Four heat dissipation holes 10.2 are left on both sides of the encapsulation shell 10 for heat dissipation of the acquisition card package 1 and the battery module 2. A rectangular groove 10.3 is left on the side of the encapsulation shell 10 near the shock-absorbing plate 11 for installing a rectangular sealing ring 14 to achieve waterproof and dustproof sealing. A through hole 11.1 is provided on the shock-absorbing plate 11 near the acquisition card package 1 for connecting the acquisition card package 1 and the metal strain gauge lead wire. An annular groove 11.2 is machined on the side of the through hole near the track plate 9 under test, and an O-ring 15 is installed on it to achieve waterproof and dustproof sealing. The metal strain gauge is directly bonded to the track plate 9 under test.

[0022] 2. Calibration method for wireless strain acquisition system like Figure 5 As shown, this embodiment includes the following steps: S1: Perform 1:1 three-dimensional modeling of the test stand 16 and the specimen plate 17, import the three-dimensional model into Workbench for simulation, find two sets of symmetrical positions on the specimen plate, and require that the strain values ​​of each set of symmetrical positions are the same, denoted as A and a and B and b respectively. S2: Based on the location found in the simulation, attach the strain gauge to the corresponding position on the specimen plate, and apply an external force to the specimen plate with the same magnitude as that at the simulation position; use two channels of the DH5902N rugged data acquisition system to measure the strain at positions A and B respectively, and use two channels 1 and 2 of the strain acquisition card to measure the strain at positions a and b. S3: Perform polynomial curve fitting on the two sets of data corresponding to the above measurements (i.e., A and a, B and b) respectively, find the corresponding relationship, determine the sensitivity coefficient of the strain acquisition card, and complete the calibration of the two channels 1 and 2 of the strain acquisition card. S4: Following the calibration methods for channels 1 and 2 described above, complete the calibration of channels 3 and 4; S5: Test the calibrated strain acquisition card to verify the accuracy of the calibration.

[0023] like Figure 6 As shown, the calibration device required for the strain calibration method has 11 through holes on the sample plate 17. The central through hole is called the load hole 17.1. The hook screw 18 is fixed to the load hole 17.1 by two nuts 19. Two different weights are suspended on the hook screw 18, so that different strains are generated at the strain gauge attachment point on the sample plate 17. The remaining 10 through holes on the sample plate 17 form 5 sets of positioning holes 17.2, which are fixed to the mounting holes 16.1 on the stand 16 by bolts. When the same weight is suspended by the hook screw 18, by adjusting the combination of the five sets of positioning holes 17.2 and mounting holes 16.1, five sets of strain data can be generated at the strain gauge attachment point.

[0024] After an external force was applied to the sample plate, the strains acquired using the DH5902N rugged data acquisition system and strain acquisition card were recorded as follows: and The channels are represented using CH1, CH2, CH3, and CH4; for each channel... and ,use Relationship fitting, find the corresponding channel and Determine the sensitivity coefficient of the strain gauge and complete the calibration of the four channels of the strain gauge; for example... Figure 7 For calibration test data, Strain data acquired by the DH5902N rugged data acquisition system. The strain data acquired by the strain acquisition card. This data is obtained after fitting the strain gauge. Based on the fitting relationship, the strain gauge is calibrated and then packaged. After packaging, the strain gauge and the DH5902N rugged data acquisition system are retested and compared. The results are as follows: Figure 8 As shown, Strain data acquired by the DH5902N rugged data acquisition system. The strain data acquired by the strain acquisition card shows that the calibration effect of the strain acquisition card is good.

Claims

1. A calibration method for a wireless strain acquisition system encapsulated in a tracked running structure, characterized in that: The wireless strain acquisition system is equipped with an acquisition card package that integrates a four-channel strain acquisition module; a calibration device is used to calibrate the four-channel strain acquisition module; The calibration device includes a stand (16) and a sample plate (17); the sample plate (17) has 11 through holes, the central through hole being a load hole (17.1), and a hook screw (18) is fixedly installed in the load hole (17.1) by two nuts (19); the remaining 10 through holes of the sample plate (17) form 5 sets of positioning holes (17.2), and the sample plate (17) can be detachably installed in the mounting hole (16.1) of the stand (16) by bolts engaging the positioning holes (17.2); two different weights are suspended by the hook screw (18) to generate different magnitudes of strain in the strain gauge bonding area of ​​the sample plate (17); under the condition of suspending the same weight, by adjusting the assembly combination of the five sets of positioning holes (17.2) and the mounting hole (16.1) of the stand, five different strain data can be obtained at the strain gauge bonding position; The calibration method includes the following steps: S1: Establish a 1:1 three-dimensional model of the test stand (16) and the test specimen plate (17), import the three-dimensional model into the Workbench finite element simulation software for simulation calculation, determine two sets of symmetrical measuring points on the test specimen plate (17), the theoretical strain values ​​of each set of symmetrical measuring points are equal, and the two sets of measuring points are marked as A, a and B, b respectively. S2: According to the measurement point positions determined by simulation, strain gauges are pasted on the sample plate (17), and an external force consistent with the magnitude and position of the load under simulation is applied to the sample plate (17); the strain of measurement points A and B is collected by two channels of the DH5902N rugged data acquisition system, and the strain of measurement points a and b is collected simultaneously by channels 1 and 2 of the strain acquisition card. S3: Perform polynomial curve fitting on the two sets of test data corresponding to measuring point A and measuring point a, and measuring point B and measuring point b respectively, establish the mapping relationship between standard strain and strain output by the data acquisition card, solve the sensitivity coefficient of the strain acquisition card, and complete the calibration of channel 1 and channel 2 of the strain acquisition card; S4: Reuse the calibration methods of channels 1 and 2 to complete the calibration of channels 3 and 4 of the strain acquisition card in sequence; S5: Conduct synchronous comparison tests using the calibrated strain acquisition card to verify the channel calibration accuracy.

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