Automatic scanning device and method for volume resistivity of conductive composite material

Abstract

The invention provides an automatic scanning device and method for the volume resistivity of a conductive composite material, and belongs to the field of civil engineering material detection and automatic testing. The device comprises a portal frame module, a self-adaptive conductive bearing platform, a three-axis linkage scanning terminal, a visual perception module and an intelligent control system. The self-adaptive conductive bearing platform serves as a common lower electrode, a micropore conductive elastomer layer is arranged on the surface of the self-adaptive conductive bearing platform, and the elastomer layer deforms through negative pressure adsorption so as to be tightly attached to the bottom of the test piece; the visual perception module identifies the contour of a test piece and constructs a digital coordinate system, and the three-axis linkage scanning terminal drives the elastic pressurization probe assembly at the tail end to scan and measure the upper surface of the test piece under the coordination of the intelligent control system. According to the method, the problems of tedious bottom contact processing, low manual measurement efficiency, sparse data and poor consistency in a traditional method are solved, and efficient and accurate evaluation of the volume resistivity distribution of the conductive composite material is realized.

Description

Technical Field

[0001] This invention belongs to the field of civil engineering material testing and automated testing technology, and particularly relates to an automated scanning device and method for the volume resistivity of conductive composite materials. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Conductive composite materials, such as functional materials prepared by incorporating conductive phases like steel fibers or carbon fibers into an asphalt concrete matrix, have become a research hotspot in the field of civil engineering materials due to their enormous application potential in areas such as electromagnetic induction heating for snow and ice melting on road surfaces and health monitoring of transportation infrastructure. The macroscopic conductivity of these materials and their functional efficiency in applications fundamentally depend on the dispersion state and spatial uniformity of the conductive filler within the insulating matrix. Therefore, refined and quantitative characterization of the volume resistivity spatial distribution of material specimens is a crucial step in evaluating the quality of their fabrication process, the quality of the conductive network construction, and their ultimate reliability.

[0004] Currently, in laboratory research and engineering practice, the measurement of volume resistivity of such composite materials mostly follows traditional methods, typically employing high-performance high-resistivity meters, such as the Keithley 6517B high-resistivity meter, as the core measuring instrument, along with simple self-made test fixtures or handheld probes. However, this traditional method has significant drawbacks in terms of both measurement efficiency and accuracy.

[0005] First, to eliminate the contact resistance between the rough bottom surface of the specimen and the electrode, traditional methods require attaching conductive tape to the bottom of the specimen and repeatedly compacting it with a roller. This process is cumbersome, time-consuming, and labor-intensive, and it is difficult to ensure the flatness of the tape. Air bubbles or wrinkles can introduce significant contact errors. Second, the current method of manually holding a probe to measure the specimen surface point by point is problematic because manual operation makes it difficult to precisely control the probe's perpendicularity and downward pressure, resulting in significant data dispersion. Furthermore, manual measurement is extremely inefficient, typically only allowing testing at a few fixed points, making it impossible to obtain high-density resistance data to construct a detailed resistivity distribution map, and thus failing to comprehensively reflect the conductive network structure within the material. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention provides an automated scanning device and method for the volume resistivity of conductive composite materials. It solves the bottom contact problem by using an adaptive conductive bearing platform and solves the problems of testing efficiency and accuracy by using a vision servo triaxial scanning system, thereby realizing high-density, non-destructive, and automated resistivity tomography of specimens of arbitrary shapes.

[0007] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions: The first aspect of this invention provides an automated scanning device for the volume resistivity of conductive composite materials; An automated scanning device for the volume resistivity of conductive composite materials, comprising: gantry module (1); An adaptive conductive bearing platform (2) is set at the bottom center of the gantry module (1) to adsorb and fix the test piece (6) and establish bottom electrical contact; The three-axis linkage scanning terminal (3) is set above the gantry module (1) and serves as the moving upper electrode for measurement; The visual perception module (4) is fixed above the gantry frame module (1) by adjusting the bracket; The intelligent control system (5) is electrically connected to the adaptive conductive bearing platform (2), the three-axis linkage scanning terminal (3), the visual perception module (4), and the external high-resistance meter, respectively. The surface of the adaptive conductive bearing platform (2) is provided with a microporous conductive elastomer layer (23). The microporous conductive elastomer layer (23) undergoes elastic deformation through negative pressure adsorption to fill the microscopic voids at the bottom of the test piece (6). The visual perception module (4) is used to acquire the contour shape of the test piece (6) and construct a digital coordinate system; The three-axis linkage scanning terminal (3) is used to perform matrix scanning contact of preset measurement points in the digital coordinate system under the drive of the intelligent control system (5).

[0008] As a further technical solution, the gantry frame module (1) includes a rectangular base frame (11), and adjustable horizontal feet (12) are installed at the four corners of the lower surface of the base frame (11); two columns (13) are vertically fixed on both sides of the base frame (11), and the tops of the two columns (13) are fixed by crossbeams (14).

[0009] As a further technical solution, the adaptive conductive bearing platform (2) includes, from bottom to top, a negative pressure cavity base (21), a conductive porous support plate (22), and a microporous conductive elastomer layer (23). The negative pressure cavity base (21) has a milled negative pressure buffer chamber (211) inside, and an air extraction port (212) is provided on the side wall; the bottom surface of the negative pressure cavity base (21) is provided with mounting ears (25), which are locked to the base frame (11) by insulating gaskets; The conductive porous support plate (22) is fixedly sealed at the top opening of the negative pressure cavity base (21); The microporous conductive elastomer layer (23) is laid on the upper surface of the conductive porous support plate (22) as an interface that directly contacts the test piece (6).

[0010] As a further technical solution, the negative pressure cavity base (21) is also provided with a grounding terminal (24), which is connected to an external high resistance meter through a shielded cable.

[0011] As a further technical solution, the three-axis linkage scanning terminal (3) is installed on the crossbeam (14) of the gantry module (1), including an X-axis module fixed to the lower surface of the crossbeam (14), a Y-axis module vertically fixed to the X-axis connecting plate, and a Z-axis module (30) vertically fixed to the slider of the Y-axis module.

[0012] As a further technical solution, the Z-axis module (30) integrates a servo motor (31) and a grating ruler (32), and a cantilever mounting base (34) is fixed on the slider of the Z-axis module (30). The end of the cantilever mounting base (34) is equipped with an elastic pressure probe assembly, which includes an insulating clamping block (35) and a conductive spring probe (33). The insulating clamping block (35) is fixed to the cantilever mounting base (34) by screws, and the conductive spring probe (33) is press-fitted into the mounting through hole of the insulating clamping block (35).

[0013] As a further technical solution, the visual perception module (4) includes an industrial camera (41) and a ring-shaped shadowless light source (42); the industrial camera (41) is fixed to the side of the crossbeam (14) by adjusting the bracket, and the lens is vertically downward aligned with the component under test (6) of the adaptive conductive bearing platform (2); the ring-shaped shadowless light source (42) is sleeved on the outer ring of the lens of the industrial camera (41) to provide uniform illumination.

[0014] As a further technical solution, the intelligent control system (5) is configured to perform at least one of the following steps: Control the negative pressure adsorption start and stop of the adaptive conductive bearing platform (2); Receive and process the image data of the visual perception module (4) to identify the specimen outline and plan the coordinates of the measurement points; Drive the three-axis linkage scanning terminal (3) to move according to the planned coordinates, and control the elastic pressure probe assembly to press down and pick up; The external high-resistance meter is triggered to acquire and transmit resistance data when the probe contact is stable.

[0015] A second aspect of the present invention provides an automated scanning method for the volume resistivity of conductive composite materials.

[0016] An automated method for scanning the volume resistivity of conductive composite materials includes: Step S1: Place the test piece (6) on the microporous conductive elastomer layer (23) of the adaptive conductive bearing platform (2); Step S2: Activate the negative pressure adsorption function of the adaptive conductive bearing platform (2) to cause the microporous conductive elastomer layer (23) to undergo elastic deformation so as to tightly adsorb and adhere to the bottom of the test piece (6) and establish a bottom electrical connection. Step S3: The image of the test piece (6) is acquired by the visual perception module (4), and the edge contour is identified by the intelligent control system (5). Within the contour range, a set of detection point coordinates is planned. Step S4, the intelligent control system (5) drives the three-axis linkage scanning terminal (3) to move to each detection point in sequence according to the detection point coordinate set; at each detection point, the elastic pressure probe assembly is controlled to press down to contact the upper surface of the test piece (6) and trigger the external high resistance meter to collect resistance data; Step S5: After traversing all detection points, calculate the volume resistivity based on the collected resistance data and the thickness of the test piece (6), and generate the resistivity distribution information inside the test piece (6).

[0017] As a further technical solution, at each detection point, the elastic pressure probe assembly is controlled to press down and contact the upper surface of the test piece (6), including: The Z-axis module (30) of the three-axis linkage scanning terminal (3) is controlled to press down a preset stroke, compressing the spring inside the conductive spring probe (33) and applying a constant contact pressure to the surface of the test piece (6).

[0018] The above one or more technical solutions have the following beneficial effects: (1) The adaptive conductive bearing platform provided by this invention integrates a negative pressure adsorption system and a microporous conductive elastomer layer as its core structure. This design abandons the traditional process of pasting conductive tape, allowing the test specimen to be placed and tested immediately. When the negative pressure is activated, the flexible and conductive microporous conductive elastomer layer undergoes adaptive deformation under atmospheric pressure, actively filling the microscopic unevenness and gaps on the bottom surface of the specimen, forming a large-area, tight physical bond. This not only eliminates the tedious and time-consuming pretreatment steps and shortens the preparation time, but also greatly increases the effective contact area and minimizes the contact interface resistance while maintaining a stable state. It fundamentally eliminates random errors caused by bubbles, wrinkles, or uneven pasting, ensuring high consistency and high reliability of the bottom electrical connection.

[0019] (2) The industrial camera used in this invention can quickly identify the contour of specimens of any shape and automatically plan dense measurement points, solving the problem of sparse and irregular manual point placement, making it possible to acquire hundreds to thousands of high-density data points. Secondly, the three-axis precision motion module (especially the Z-axis with integrated grating ruler) drives the conductive spring probe, which can reach each preset measurement point with micron-level repeatability. Finally, the use of the internal spring structure of the conductive spring probe allows the probe to apply constant and controllable contact pressure to measurement points with different hardness or flatness under Z-axis control. This constant pressure contact mechanism completely overcomes the defects of uncontrollable pressure and perpendicularity when manually holding the probe, ensuring that the contact conditions for each measurement are highly consistent, thereby making the massive resistance data collected have excellent repeatability, comparability and low dispersion.

[0020] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0022] Figure 1 This is a front view schematic diagram of the overall structure of the device in the first embodiment.

[0023] Figure 2 This is a schematic diagram of the adaptive conductive bearing platform in the first embodiment.

[0024] Figure 3 This is a schematic diagram of the structure of the three-axis linkage scanning terminal and the elastic pressure probe assembly in the first embodiment.

[0025] Figure 4 This is a schematic diagram of the visual recognition and placement logic for specimens of different shapes in the second embodiment.

[0026] The components include: 1. Gantry frame module; 11. Base frame; 12. Foot; 13. Column; 14. Horizontal beam; 2. Adaptive conductive bearing platform; 21. Negative pressure chamber base; 211. Negative pressure buffer chamber; 212. Air extraction port; 22. Conductive porous support plate; 23. Microporous conductive elastomer layer; 24. Grounding terminal; 25. Mounting ear; 3. Three-axis linkage scanning terminal; 30. Z-axis module; 31. Servo motor; 32. Grating ruler; 33. Conductive spring probe; 34. Cantilever mounting base; 35. Insulating clamping block. Detailed Implementation

[0027] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0028] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations of the present invention.

[0029] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0030] Example 1 This embodiment discloses an automated scanning device for the volume resistivity of conductive composite materials. By setting a microporous conductive elastomer layer and a negative pressure adsorption system on the surface of an adaptive conductive bearing platform, the device utilizes negative pressure to tightly adhere the flexible conductive layer to the bottom of the specimen, effectively replacing the cumbersome process of traditionally applying conductive tape and achieving rapid, low-resistance contact of the bottom electrode. A visual perception module can identify the contours of specimens of arbitrary shapes. Combined with a triaxial robotic arm and elastic probe, it achieves high-density, constant-pressure automated scanning of hundreds of measurement points on the specimen surface. This effectively solves the problems of limited manual sampling, large contact errors, and low efficiency in existing technologies, providing a high-precision tomographic imaging method for evaluating the internal uniformity of materials such as conductive asphalt concrete.

[0031] like Figure 1 As shown, an automated scanning device for the volume resistivity of conductive composite materials consists of a gantry module (1), an adaptive conductive bearing platform (2), a three-axis linkage scanning terminal (3), a vision perception module (4), and an intelligent control system (5). The components work together to achieve automated and high-precision scanning testing of the volume resistivity of conductive composite material specimens (6).

[0032] The gantry frame module (1) serves as the supporting skeleton of the entire device and is constructed using high-strength industrial aluminum profiles, featuring a stable structure and strong anti-interference capabilities. Its core components include a rectangular base frame (11), which adopts an integrally formed aluminum profile splicing structure to ensure overall rigidity. Adjustable level feet (12) are installed at the four corners of the lower surface of the base frame (11). The adjustable level feet (12) adopt a threaded adjustment structure, and the levelness of the base frame (11) can be precisely controlled by rotating the adjustment knob. At the same time, it can effectively isolate the influence of ground vibration on the test accuracy, ensuring that the device can maintain a stable working state in different site environments.

[0033] Two columns (13) are vertically fixed to both sides of the base frame (11) by high-strength bolts. The columns (13) are made of thickened aluminum profiles and the surface is anodized, which has both rust resistance and wear resistance. The top of the two columns (13) is fixed by a crossbeam (14). The connection between the crossbeam (14) and the columns (13) is double-fixed with reinforced angle brackets and bolts to form a stable "door" shaped structure, which provides a reliable installation reference for the motion mechanism of the three-axis linkage scanning terminal (3), vision perception module (4) and other moving parts above, and ensures the running accuracy of each moving part.

[0034] like Figure 2 As shown, the adaptive conductive bearing platform (2) is located at the bottom center of the gantry frame module (1), that is, the central area of ​​the base frame (11), and is used to adsorb and fix the test piece (6) and establish a stable bottom electrical contact. From bottom to top, it includes a negative pressure cavity base (21), a conductive porous support plate (22) and a microporous conductive elastomer layer (23). The structure of each layer is closely matched to realize the dual functions of negative pressure adsorption and conductive connection.

[0035] The negative pressure chamber base (21) is made of highly conductive brass material and precision machined by CNC to ensure good conductivity and structural accuracy. A hollow negative pressure buffer chamber (211) is milled inside the base. The volume of this chamber is optimized to effectively stabilize the negative pressure and prevent pressure fluctuations during adsorption from causing the specimen (6) to shift. An air extraction port (212) is provided on the side wall of the negative pressure chamber base (21). This port adopts a standard air pipe connector structure and is connected to an external vacuum pump through a high-temperature resistant and anti-aging air pipe. The power of the vacuum pump can be flexibly adjusted according to the size of the specimen to ensure that the adsorption force meets the fixation requirements of specimens of different specifications.

[0036] Meanwhile, the bottom surface of the negative pressure chamber base (21) is also provided with mounting ears (25), and mounting holes are provided on the mounting ears (25). The mounting ears (25) are locked to the base frame (11) by insulating gaskets and high-strength bolts. The insulating gaskets are made of polytetrafluoroethylene material with a thickness of 3mm, which effectively realizes the electrical isolation between the negative pressure chamber base (21) and the frame, and avoids stray current interference with the test data.

[0037] In addition, the negative pressure cavity base (21) is provided with a grounding terminal (24) on the side. The grounding terminal (24) adopts a copper terminal structure and is connected to the LO terminal of an external high resistance meter (such as Keithley 6517B) through a shielded cable, so that the entire adaptive conductive bearing platform (2) is used as the common lower electrode for measurement, ensuring the stability of electrical signal transmission.

[0038] The conductive porous support plate (22) is made of sintered metal mesh with a thickness of 2 mm and a porosity of 35%, which ensures sufficient mechanical strength to support the test piece (6) and also ensures smooth airflow. The conductive porous support plate (22) is fixedly sealed to the top opening of the negative pressure chamber base (21) by a sealing ring. The sealing ring is made of silicone rubber to ensure the airtightness of the negative pressure chamber and avoid the problem of air leakage leading to adsorption failure.

[0039] A microporous conductive elastomer layer (23) is laid on the upper surface of the conductive porous support plate (22) to serve as the interface in direct contact with the test piece (6). This layer is selected with a volume resistivity of less than 10Ω. The plate is made of silver-doped conductive silicone with a diameter of 5-10 μm and is filled with silver powder filler with a particle size of 5-10 μm, which significantly improves its conductivity. In order to achieve the vacuum adsorption function, the microporous conductive elastomer layer (23) is prefabricated with a micron-sized pore array that runs through the thickness direction using laser drilling technology. The pore diameter is 0.2 mm and the pore spacing is 2 mm. This pore array is connected to the pores of the conductive porous support plate (22) to form a complete negative pressure adsorption gas path, ensuring that the negative pressure can be uniformly transmitted to the bottom of the specimen, so that the elastomer layer is tightly attached to the surface of the specimen.

[0040] Furthermore, the three-axis linkage scanning terminal (3) is inverted and installed on the crossbeam (14) of the gantry frame module (1) as a moving upper electrode for measurement, used to drive the probe to move in space and realize matrix scanning of the specimen surface. The three-axis linkage scanning terminal (3) includes an X-axis module fixed to the lower surface of the crossbeam (14), a Y-axis module vertically fixed to the X-axis connecting plate, and a Z-axis module vertically fixed to the slider of the Y-axis module. The X-axis module, Y-axis module and Z-axis module (30) are used to drive the probe to move along the X, Y and Z axes. Their operating principle is the same, and they are all realized by using a precision ball screw linear module. The transmission accuracy can reach ±0.01mm, ensuring the accuracy of the measurement point positioning.

[0041] In this embodiment, the effective stroke of the Z-axis module (30) is 100 mm, which meets the testing requirements of specimens with different thicknesses. The Z-axis module (30) integrates a servo motor (31) and a high-precision grating ruler (32). The resolution of the grating ruler (32) is 0.1 μm, which can achieve micron-level pressure depth control and ensure stable contact pressure between the probe and the specimen surface.

[0042] like Figure 3As shown, an L-shaped aluminum alloy cantilever mounting base (34) is bolted to the slider of the Z-axis module (30). An elastic pressure probe assembly is mounted at the end of the cantilever mounting base (34). This assembly is the core actuator for measurement and includes an insulating clamping block (35) and a conductive spring probe (33). The insulating clamping block (35) is made of polytetrafluoroethylene insulating material and is fixed to the cantilever mounting base (34) with screws. Its function is to cut off the electrical connection between the probe and the frame to avoid electrical signal interference.

[0043] The conductive spring probe (33) is press-fitted into the mounting through hole of the insulating clamping block (35). The probe head is made of gold-plated beryllium copper and the head is machined into a crown tooth shape. This structural design can effectively pierce the oxide layer or asphalt film on the surface of the specimen, ensuring stable conductive contact between the probe and the surface of the specimen. The tail of the conductive spring probe (33) is welded with a coaxial signal wire core, which is connected to the HI terminal of an external high-resistance meter through a shielded cable to realize the transmission of electrical signals.

[0044] During the measurement process, by controlling the downward stroke of the Z-axis module (30), the compression of the spring inside the conductive spring probe (33) can be used to apply constant contact pressure to different measurement points. The pressure range can be flexibly adjusted by the intelligent control system (5) to ensure the consistency of the contact state of each measurement point.

[0045] The visual perception module (4) is fixed to the side of the crossbeam (14) of the gantry module (1) by adjusting the bracket. It is used to acquire the contour shape of the test piece (6) and construct a digital coordinate system to provide a basis for scanning path planning. It mainly includes an industrial camera (41) and a ring shadowless light source (42). The industrial camera (41) can be a CMOS industrial camera with a resolution of 20 million pixels and a frame rate of up to 30fps, which can quickly and clearly capture images of the test piece. The field of view of the industrial camera (41) can cover the effective working area of ​​the adaptive conductive support platform (2). The height and angle of the camera can be flexibly adjusted by adjusting the bracket to ensure that the lens is vertically downward aligned with the test piece (6) on the adaptive conductive support platform (2).

[0046] The ring-shaped shadowless light source (42) is fitted around the lens of the industrial camera (41) to provide a uniform, shadowless lighting environment. At the same time, the brightness of the ring-shaped shadowless light source (42) can be steplessly adjusted by the intelligent control system (5), which can adjust the lighting intensity according to the reflective characteristics of the specimen surface, avoid image recognition errors caused by light reflection or shadows, and ensure the accuracy of specimen contour recognition.

[0047] The intelligent control system (5) is the core control unit of the entire device. It adopts an industrial-grade PLC controller as the core processor and is electrically connected to the adaptive conductive bearing platform (2), the three-axis linkage scanning terminal (3), the visual perception module (4) and the external high resistance meter through wires to realize the coordinated control and data transmission of each component.

[0048] The intelligent control system (5) is configured to perform the following core functions: (1) Control the negative pressure adsorption start and stop of the adaptive conductive bearing platform (2), and realize the rapid adsorption and release of the specimen by controlling the switch and working power of the vacuum pump; (2) is to receive and process the image data of the visual perception module (4), and has built-in advanced image processing algorithms that can quickly identify the edge contour of the specimen, remove background interference, and accurately extract the actual size and position information of the specimen. (3) Based on the identified specimen contour, the coordinates of the measuring points are automatically planned, supporting two modes: interactive point layout and parametric array point layout. Users can choose flexibly according to their testing needs. (4) Drive the three-axis linkage scanning terminal (3) to perform high-precision motion according to the planned coordinates, accurately control the movement and positioning of the X and Y axes and the pressing and picking actions of the Z axis, and ensure that the probe can accurately reach each measurement point position; (5) After the probe contacts the device and stabilizes, the external high-resistivity meter is automatically triggered to collect resistance data and receive and store the collected resistance data in real time, providing a basis for subsequent resistivity calculation.

[0049] Example 2 This embodiment discloses an automated scanning method for the volume resistivity of conductive composite materials; An automated method for scanning the volume resistivity of conductive composite materials includes: Step S1: Place the test piece (6) on the microporous conductive elastomer layer (23) of the adaptive conductive support platform (2).

[0050] Step S2: Activate the negative pressure adsorption function of the adaptive conductive bearing platform (2), causing the microporous conductive elastomer layer (23) to undergo elastic deformation to tightly adsorb and adhere to the bottom of the test piece (6), establishing a bottom electrical connection. Specifically: The negative pressure adsorption function of the adaptive conductive bearing platform (2) is activated by the intelligent control system (5). The external vacuum pump extracts the gas in the negative pressure chamber base (21) through the air extraction interface (212). The negative pressure is transmitted to the microporous conductive elastomer layer (23) through the conductive porous support plate (22). Under atmospheric pressure, the microporous conductive elastomer layer (23) undergoes elastic deformation, tightly adsorbs and adheres to the bottom of the test piece (6), fills the micro gaps, and establishes a stable, low-resistance bottom electrical connection by means of its conductive properties, without the need for additional conductive tape or silver paste.

[0051] Step S3: The visual perception module (4) acquires an image of the test piece (6), and the intelligent control system (5) identifies the edge contour and plans a set of detection point coordinates within the contour range. The industrial camera (41) of the visual perception module (4) captures a global image of the test piece (6) under uniform illumination from a ring-shaped shadowless light source (42) and transmits it to the intelligent control system (5). The intelligent control system (5) performs preprocessing such as noise reduction and edge enhancement on the image using image processing algorithms to accurately identify the edge contour of the test piece (6) and eliminate background interference. Subsequently, based on the preset measurement point density or user-input parameters, it automatically plans a uniformly distributed set of detection point coordinates within the contour range, while eliminating invalid points outside the edge safety distance to ensure the effectiveness of the detection coverage. In this embodiment, the intelligent control system (5) can perform preprocessing such as noise reduction and edge enhancement on the image using the Canny edge detection algorithm to accurately identify the edge contour of the test piece (6) and eliminate background interference. During the detection point planning process, the intelligent control system (5) uses the internally based "grid-based uniform sampling algorithm" combined with the "ray projection algorithm" to plan the measurement points. The specific process is as follows: First, the system generates the minimum bounding rectangle based on the identified contour, and generates a virtual grid of points within the rectangle according to the preset measurement point spacing; then, the ray projection algorithm is applied to judge the topological relationship between each grid point and the contour boundary one by one, and points located inside the contour are retained; finally, boundary points that are less than the preset safety distance from the contour edge are automatically removed, thereby generating the final set of valid detection point coordinates.

[0052] In step S4, the intelligent control system (5) drives the three-axis linkage scanning terminal (3) to move to each detection point in sequence according to the set of detection point coordinates; at each detection point, the elastic pressure probe assembly is controlled to press down and contact the upper surface of the test piece (6), and triggers the external high resistance meter to collect resistance data.

[0053] Figure 4A schematic diagram of visual recognition and point placement logic for specimens of different shapes is provided. Specifically, the intelligent control system (5) drives the X-axis module and Y-axis module of the three-axis linkage scanning terminal (3) to move in coordination, moving sequentially to each detection point according to the planned set of detection point coordinates. After reaching each detection point, the Z-axis module (30) is controlled to press down a preset stroke, so that the conductive spring probe (33) contacts the upper surface of the specimen (6) and continues to press down, compressing the internal spring and applying constant contact pressure to the surface of the specimen to ensure consistent contact state. After the contact is stable, the system triggers an external high-resistance meter to collect resistance data and store it in real time.

[0054] In step S5, after collecting data from all detection points, the intelligent control system (5) calls the volume resistivity formula and calculates the volume resistivity of each detection point by combining the collected resistance data and the thickness of the test piece (6) input by the user. Finally, the resistivity distribution cloud map inside the test piece (6) is generated through data processing, which intuitively presents the uniformity of the conductive phase distribution and provides a basis for material quality evaluation.

[0055] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. An automated scanning device for the volume resistivity of conductive composite materials, characterized in that, include: Gantry rack module (1); An adaptive conductive bearing platform (2) is set at the bottom center of the gantry module (1) to adsorb and fix the test piece (6) and establish bottom electrical contact; The three-axis linkage scanning terminal (3) is set above the gantry module (1) and serves as the moving upper electrode for measurement; The visual perception module (4) is fixed above the gantry frame module (1) by adjusting the bracket; The intelligent control system (5) is electrically connected to the adaptive conductive bearing platform (2), the three-axis linkage scanning terminal (3), the visual perception module (4), and the external high-resistance meter, respectively. The surface of the adaptive conductive bearing platform (2) is provided with a microporous conductive elastomer layer (23). The microporous conductive elastomer layer (23) undergoes elastic deformation through negative pressure adsorption to fill the microscopic voids at the bottom of the test piece (6). The visual perception module (4) is used to acquire the contour shape of the test piece (6) and construct a digital coordinate system; The three-axis linkage scanning terminal (3) is used to perform matrix scanning contact of preset measurement points in the digital coordinate system under the drive of the intelligent control system (5).

2. The automated volume resistivity scanning device for conductive composite materials as described in claim 1, characterized in that, The gantry frame module (1) includes a rectangular base frame (11), and adjustable horizontal feet (12) are installed at the four corners of the lower surface of the base frame (11). Two columns (13) are vertically fixed on both sides of the base frame (11), and the tops of the two columns (13) are fixed by crossbeams (14).

3. The automated volume resistivity scanning device for conductive composite materials as described in claim 1, characterized in that, The adaptive conductive bearing platform (2) includes, from bottom to top, a negative pressure cavity base (21), a conductive porous support plate (22), and a microporous conductive elastomer layer (23). The negative pressure cavity base (21) has a milled negative pressure buffer chamber (211) inside, and an air extraction port (212) is provided on the side wall; the bottom surface of the negative pressure cavity base (21) is provided with mounting ears (25), which are locked to the base frame (11) by insulating gaskets; The conductive porous support plate (22) is fixedly sealed at the top opening of the negative pressure cavity base (21); The microporous conductive elastomer layer (23) is laid on the upper surface of the conductive porous support plate (22) as an interface that directly contacts the test piece (6).

4. The automated volume resistivity scanning device for conductive composite materials as described in claim 1, characterized in that, The negative pressure cavity base (21) is also provided with a grounding terminal (24), which is connected to an external high resistance meter through a shielded cable.

5. The automated volume resistivity scanning device for conductive composite materials as described in claim 1, characterized in that, The three-axis linkage scanning terminal (3) is installed on the crossbeam (14) of the gantry module (1), including an X-axis module fixed to the lower surface of the crossbeam (14), a Y-axis module vertically fixed to the X-axis connecting plate, and a Z-axis module (30) vertically fixed to the slider of the Y-axis module.

6. The automated volume resistivity scanning device for conductive composite materials as described in claim 1, characterized in that, The Z-axis module (30) integrates a servo motor (31) and a grating ruler (32), and a cantilever mounting base (34) is fixed on the slider of the Z-axis module (30). The end of the cantilever mounting base (34) is equipped with an elastic pressure probe assembly, which includes an insulating clamping block (35) and a conductive spring probe (33). The insulating clamping block (35) is fixed to the cantilever mounting base (34) by screws, and the conductive spring probe (33) is press-fitted into the mounting through hole of the insulating clamping block (35).

7. The automated volume resistivity scanning device for conductive composite materials as described in claim 1, characterized in that, The visual perception module (4) includes an industrial camera (41) and a ring-shaped shadowless light source (42); the industrial camera (41) is fixed to the side of the crossbeam (14) by an adjustment bracket, and the lens is vertically downward aligned with the component under test (6) of the adaptive conductive bearing platform (2); the ring-shaped shadowless light source (42) is fitted around the outer ring of the lens of the industrial camera (41) to provide uniform illumination.

8. The automated volume resistivity scanning device for conductive composite materials as described in claim 1, characterized in that, The intelligent control system (5) is configured to perform at least one of the following steps: Control the negative pressure adsorption start and stop of the adaptive conductive bearing platform (2); Receive and process the image data of the visual perception module (4) to identify the specimen outline and plan the coordinates of the measurement points; Drive the three-axis linkage scanning terminal (3) to move according to the planned coordinates, and control the elastic pressure probe assembly to press down and pick up; The external high-resistance meter is triggered to acquire and transmit resistance data when the probe contact is stable.

9. A scanning method based on the automated volume resistivity scanning device for conductive composite materials according to any one of claims 1 to 8, characterized in that, include: Step S1: Place the test piece (6) on the microporous conductive elastomer layer (23) of the adaptive conductive bearing platform (2); Step S2: Activate the negative pressure adsorption function of the adaptive conductive bearing platform (2) to cause the microporous conductive elastomer layer (23) to undergo elastic deformation so as to tightly adsorb and adhere to the bottom of the test piece (6) and establish a bottom electrical connection. Step S3: The image of the test piece (6) is acquired by the visual perception module (4), and the edge contour is identified by the intelligent control system (5). Within the contour range, a set of detection point coordinates is planned. Step S4, the intelligent control system (5) drives the three-axis linkage scanning terminal (3) to move to each detection point in sequence according to the detection point coordinate set; at each detection point, the elastic pressure probe assembly is controlled to press down to contact the upper surface of the test piece (6) and trigger the external high resistance meter to collect resistance data; Step S5: After traversing all detection points, calculate the volume resistivity based on the collected resistance data and the thickness of the test piece (6), and generate the resistivity distribution information inside the test piece (6).

10. The automated scanning method for volume resistivity of conductive composite materials as described in claim 9, characterized in that, At each test point, the elastic pressure probe assembly is controlled to press down and contact the upper surface of the test piece (6), including: The Z-axis module (30) of the three-axis linkage scanning terminal (3) is controlled to press down a preset stroke, compressing the spring inside the conductive spring probe (33) and applying a constant contact pressure to the surface of the test piece (6).

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