Visual tactile sensor capable of measuring temperature

Abstract

The invention relates to a temperature measurement visual tactile sensor. The sensor comprises a main body, a main body shell and a detachable touch sensing structure on the top of the main body shell, in the main body, a uniform light film is additionally arranged between the light isolation ring and the LED lamp panel below the light isolation ring; the detachable touch sensing structure comprises a detachable structure shell and a sensing layer; wherein the sensing layer is mounted at the top of the inner side of the shell with the detachable structure; the sensing layer comprises a PDMS layer, a quartz glass layer, a semitransparent silica gel layer, a PDMS layer doped with a thermochromic material, a first reflecting layer and a second reflecting layer; the second reflecting layer covers the first reflecting layer. The temperature range of 35-75 DEG C is covered, the temperature change can be visually displayed, the response time and the recovery time are extremely short, the high-precision temperature monitoring capability is achieved, and the temperature sensor is suitable for various daily temperature monitoring scenes.

Description

Technical Field

[0001] The present invention belongs to the field of tactile sensor perception, and specifically relates to a novel structural design based on a visual tactile sensor. Based on this structural sensor, surface texture reconstruction and temperature perception can be achieved. Background Art

[0002] With the rapid development of artificial intelligence, robotics, and virtual reality technologies, multifunctional sensors capable of visual and tactile fusion are playing an increasingly important role in precision manipulation, intelligent interaction, and perception of complex environments. Existing visual and tactile sensors typically have fixed structures and single functions, making them difficult to meet diverse application requirements. For example, existing sensors can only recognize surface textures but cannot sense temperature.

[0003] The paper (Changyi Lin, et al. 9DTact: A Compact Vision-Based Tactile Sensor for Accurate 3D Shape Reconstruction and Generalizable 6D Force Estimation [J]. IEEE Robotics and Automation Letters, 2024, 9(2): 923–930.) designed a visual-tactile sensor. The paper used a monochromatic light source for three-dimensional reconstruction, but the distribution of the light source was uneven, which reduced the accuracy of the sensor. At the same time, the preparation process of the perception layer designed in the paper was complex, making it very difficult to replicate these sensors in the field of robotics. Finally, the sensor only has the function of three-dimensional reconstruction and cannot realize temperature perception. The single perception function cannot meet the perception requirements of machine tactile.

[0004] Therefore, the present invention improves the uniformity of illumination by introducing a uniform light film, simplifies the preparation process by improving the preparation process of the reflective film, and makes it more convenient to apply it to the field of robotics. Finally, a temperature sensing layer is prepared using thermochromic material, so that the sensor can realize the temperature sensing function on the basis of completing three-dimensional reconstruction to meet various application requirements. Summary of the Invention

[0005] The purpose of this invention is to provide a detachable visual-tactile sensor to address the inability of traditional visual-tactile sensors to adapt to diverse application scenarios. The sensor's modular design, enabled by the provision of a detachable tactile sensing structure, allows for easy replacement of different functions to suit different scenarios. The temperature sensing function incorporates thermochromic materials, resulting in significant color changes at different temperatures. This sensor covers a temperature range of 35°C to 75°C, can intuitively display temperature changes, and features extremely fast response and recovery times. It offers high-precision temperature monitoring capabilities, making it suitable for a variety of everyday temperature monitoring scenarios.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A temperature measuring visual tactile sensor, the sensor comprising a main body, a main body shell and a detachable tactile sensing structure on the top thereof;

[0008] The main body is the part below the light isolation ring in the 9DTact sensor, and a light uniforming film is added between the light isolation ring and the LED light board below it;

[0009] The main body shell has a height matching that of the internal light isolation ring and is provided with slots at the front and back;

[0010] The detachable tactile sensing structure comprises a detachable structural shell and a sensing layer; wherein the sensing layer is mounted on the inner top of the detachable structural shell;

[0011] The sensing layer comprises a PDMS layer, a quartz glass layer, a translucent silicone layer, a PDMS layer doped with a thermochromic material, a first reflective layer, and a second reflective layer. The PDMS layer, the quartz glass layer, and the translucent silicone layer are laminated together from bottom to top. The translucent silicone layer is doped with a thermochromic material, and the first reflective layer covers the translucent silicone layer and the PDMS layer. The second reflective layer covers the first reflective layer.

[0012] The detachable structural shell is made of the same material and has the same side length as the main shell. It has buckles on the front and back that match the slots on the top of the main shell for plugging and fixing on the main shell.

[0013] The PDMS layer doped with thermochromic material is composed of nine discs arranged in a 3*3 matrix, with a thickness of 0.1 to 0.2 mm. Each disc is made of a mixture of a thermochromic material, a PDMS prepolymer, and a curing agent in a mass ratio of 3:10:1.

[0014] The thermochromic material is a thermochromic powder of model WB-3665 produced by Lijin Technology Co., Ltd.

[0015] The material of the light-homogenizing film is polycarbonate and has a thickness of 0.1 mm;

[0016] The thickness of the PDMS layer is 1 to 2 mm;

[0017] The thickness of the quartz glass layer is 1.8 to 2.2 mm;

[0018] The translucent silicone layer is a silicone with a Shore hardness of 5;

[0019] The first reflective layer is made of 400-mesh copper powder with a thickness of 0.05-0.07 mm.

[0020] The thickness of the second reflective layer is 0.2-0.3 mm, and the second reflective layer is formed by mixing copper powder, silica gel and melanin in a mass ratio of 1:26:1.

[0021] The beneficial effects of the present invention are:

[0022] 1. By designing a removable top layer, users can quickly swap out sensing layers for different functions based on their needs. This modular design significantly enhances the sensor's flexibility and adaptability, enabling it to meet diverse application scenarios, such as surface texture recognition and temperature sensing. This eliminates the need to redesign or remanufacture the entire sensor, saving time and manufacturing costs. Traditional sensors fabricated using silicone can take up to two days to prepare, while the removable top layer reduces this time to just one hour, a 97% improvement in efficiency.

[0023] 2. The compact layout of the sensor's lighting, camera, and tactile sensing layer allows it to integrate more functions within a limited space while maintaining high performance. Measuring 32×28×24.5mm, the sensor can be integrated into the fingertips of any commercially available robotic gripper and weighs only 40g. The fixed position of the lighting and camera ensures even light distribution and effectively avoids glare caused by light reflections, thereby improving image clarity and accuracy, with image resolution reaching 2k.

[0024] 3. The sensing layer utilizes a multilayer structure consisting of a hard PDMS layer, a translucent silicone layer, and a soft PDMS layer doped with copper powder and melanin. This multilayer design enhances the sensor's sensing capabilities. The hard PDMS layer provides structural strength and light transmission, the translucent silicone layer enables tactile information to be converted into depth information, and the soft PDMS layer absorbs light and captures minute textures. This structural design enables the sensor to more accurately perceive the texture and shape of external objects, capable of recognizing textures as small as 0.1mm.

[0025] 4. The texture recognition function accurately reconstructs the surface texture of an object in three dimensions by mapping pixel change values ​​to pressure depth. Through the sensor's perception layer and image processing technology, it can accurately perceive complex surface structures, providing reliable depth information and texture recognition with an error of 0.001mm.

[0026] 5. By incorporating thermochromic materials, the sensor undergoes distinct color changes at different temperatures, providing intuitive temperature indication. This temperature recognition function covers a wide temperature range (35°C to 75°C) and offers rapid response (0.1s) and recovery (0.2s). Compared to traditional temperature sensors, the temperature sensing technology of this invention offers better visual quality and faster response speed.

[0027] 6. The introduction of the light-homogenizing film and PDMS layer reduced the variance of the grayscale distribution of the reference image by 46.5% and the standard deviation of the local contrast by 21.5%, effectively improving the illumination uniformity.

[0028] 7. Using the reconstruction method of pixel value changes to depth mapping, the three-dimensional shape reconstruction of the contact object was successfully achieved, achieving a spatial resolution of 100μm and an average absolute error of 0.0512mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is an exploded diagram of the structure of a traditional visual tactile sensor;

[0030] Figure 2 This is an exploded view of the structure of the novel visual-tactile sensor according to the present invention;

[0031] Figure 3 This is a cross-sectional view of the structure of the novel visual-tactile sensor according to the present invention;

[0032] Figure 4 This is a perspective view of the structure of the novel visual-tactile sensor according to the present invention;

[0033] Figure 5 This is a perspective view of the installation of the detachable structure of the present invention;

[0034] Figure 6 This is an anatomical diagram of the sensing layer of the sensor of the present invention;

[0035] Figure 7 A perception map of the sensor of the present invention for the functional perception layer of surface texture three-dimensional reconstruction;

[0036] Figure 8 This is the result of 3D reconstruction of surface texture;

[0037] Figure 9 The sensing temperature distribution of the temperature recognition sensing layer;

[0038] Figure 10 A diagram showing the corresponding relationship between the state and results of the temperature recognition perception layer;

[0039] Figure 11 The response speed and recovery speed of the sensing layer for temperature recognition function;

[0040] In the accompanying drawings: 1-light-uniform film; 2-main body shell; 3-PDMS layer; 4-detachable structural shell; 5-quartz glass layer; 6-translucent silicone layer; 7-PDMS layer doped with thermochromic material; 8-first reflective layer; 9-second reflective layer. DETAILED DESCRIPTION

[0041] Specific embodiments are given below in conjunction with the accompanying drawings. The specific embodiments are only used to introduce the technical solutions of the present invention in detail and are not intended to limit the scope of protection of the present application.

[0042] The present invention provides a temperature-measurable visual tactile sensor that is an improvement on the currently known devices. The 9DTact sensor in the current paper (ChangyiLin, et al. 9DTact: A Compact Vision-Based Tactile Sensor for Accurate 3D Shape Reconstruction and Generalizable 6D Force Estimation [J]. IEEE Robotics and Automation Letters, 2024, 9(2): 923–930.) includes an LED light board, a camera, a light isolating ring, connecting components (such as M2 hot melt nuts and M2×3mm screws) and a sensor base as a main body. The LED light board is composed of a CN5711 driver chip, a pull-up resistor and 8 4800k white LEDs; the camera is a 160° wide-angle OV5647 camera with 5 million pixels; the light isolating ring is a square annular hollow structure that can be put on the camera to reduce glare caused by incident light hitting the camera.

[0043] The structure of the temperature-measurable visual-tactile sensor of the present invention is as follows: Figure 2 As shown, it includes a main body, a main body shell 2 and a detachable tactile sensing structure on the top thereof;

[0044] The main body is the light isolating ring (with hot melt nuts around it) and the part below it in the current technology, and a light uniforming film 1 is added between the light isolating ring and the LED light board below it;

[0045] The main housing 2 has a height matching that of the internal light-isolating ring and is provided with slots at the front and back.

[0046] The detachable tactile sensing structure is as follows Figure 3 As shown, it includes a detachable structural shell 4 and a sensing layer; wherein the sensing layer is installed on the inner top of the detachable structural shell 4;

[0047] The perception layer is as follows Figure 6 As shown, the composition includes a PDMS layer 3, a quartz glass layer 5, a translucent silicone layer 6, a PDMS layer 7 doped with a thermochromic material, a first reflective layer 8, and a second reflective layer 9. The PDMS layer 3, the quartz glass layer 5, and the translucent silicone layer 6 are sequentially laminated together from bottom to top. Nine circular grooves are distributed in a matrix on the translucent silicone layer 6. The thermochromic materials at nine different temperatures are embedded in the grooves to form the PDMS layer 7 doped with the thermochromic material. The first reflective layer 8 covers the translucent silicone layer 6 and the PDMS layer 7. The second reflective layer 9 covers the first reflective layer 8.

[0048] The detachable structural shell 4 is made of the same material and has the same side length as the main shell 2. It has buckles on the front and back, which match the slots on the top of the main shell 2 for plugging and fixing on the main shell 2.

[0049] like Figure 2 As shown, the light-diffusing film 1 is cut to the shape of the LED board, forming a rectangular shape with a square hole in the center to allow the camera to pass through. The light-diffusing film is finally attached to the LED board, evenly scattering the incident light, eliminating uneven brightness and spotting, and achieving a soft, uniform light distribution.

[0050] The material of the light-homogenizing film 1 is polycarbonate and has a thickness of 0.1 mm;

[0051] The above-mentioned main body is placed at the bottom of the main body shell 2. The main body shell 2 is an overall rectangular box-shaped structure with an internal cavity design and its dimensions are 32×28×15mm. In terms of shape, it is a flat rectangular parallelepiped as a whole, with a camera window at the bottom and a card slot corresponding to the snap structure and a positioning hole at the top for matching with the snap of the detachable structure shell 4. The positioning hole is located on the left side of the component and presents a regular circular structure. There are two positioning holes, which are arranged vertically on the left side wall of the component. Each positioning hole penetrates the wall to form a through-hole structure. The edges of the positioning holes have a slight flange treatment to ensure precise positioning. There is a reinforcing rib structure around the positioning holes to enhance the structural strength. The card slot has a distinct stepped sidewall to form a multi-step structure. The edge contour of the groove is smooth with a circular arc transition treatment. The depth of the groove is uniform and the bottom is flat.

[0052] The main housing 2 is connected to the removable structural housing 4 via a snap-fit ​​connection. The removable structural housing 4 is an overall rectangular frame structure with an open central area and dimensions of 32×28×12mm. At the bottom edge of the component, a connecting mechanism is located, consisting of two cylindrical locating pins and a snap-fit ​​assembly. This connecting mechanism can be connected to the locating holes and slots of the main housing 2 via these locating pins and snap-fit ​​assembly. The cylindrical locating pins and locating holes secure the connecting mechanism. The locating posts are cylindrical in shape, with a distinct step structure. The top diameter of the posts is smaller than the bottom diameter, forming a tapered transition zone. The bottom of each post merges with the frame structure, while the top protrudes as a docking point. The snap fastener is an elastic snap fastener, consisting of two main claws. It achieves rapid assembly and disassembly with a mating component through elastic deformation. Each claw has a stepped or boss design with a narrower middle portion, forming an elastic deformation zone. The distal end is hooked, allowing engagement when inserted into a mating hole or groove, giving it the appearance of an elastic hook. Two parallel grooves are visible on the surface of the snap fastener. The grooves are rectangular, with rounded edges, uniform depth, and smooth inner walls. The two grooves are spaced apart to form a reinforcing rib structure, and the edges of the grooves have a slight raised border to increase structural strength. The locating pins are cylindrical with a conical distal end. They are located on the sidewall or internal vertical surface of the structural component and are typically used in conjunction with the locating holes or grooves of the mating component. They are vertically distributed and arranged on the inner side of the structural component to improve the vertical positioning accuracy and stability of the assembly.

[0053] The open area of ​​the removable structural housing 4 is embedded with a quartz glass layer 5, reinforced with glue. This 2mm thick layer provides mechanical support and allows light to pass evenly, acting as a "window." A PDMS layer 3 is cast beneath the quartz glass layer. This PDMS layer is used to transmit light generated by the lighting device, reduce glare on the camera caused by reflected light, and provide mechanical strength.

[0054] A 2mm thick translucent silica gel layer 6 is cast on the quartz glass layer. Nine circular holes with a radius of 2.5mm and a depth of 0.1mm are arranged in a 3x3 matrix on the top of the layer (with a spacing of 6.2mm between adjacent holes). The holes are filled with a PDMS layer 7 doped with a thermochromic material. The translucent silicone layer is located above the quartz glass layer and is in contact with it. The translucent silicone layer is used to perceive tactile information as depth information of different brightness and darkness and reflect the light generated by the lighting device. The PDMS layer doped with thermochromic material is used to sense temperature. The thermochromic material is a powder prepared from an electron transfer type organic compound with an average particle size of 2-7 μm. When it is exposed to a specific temperature, the transfer of electrons causes the molecular structure of the organic compound to change, thereby achieving color change. The thermochromic material used in the present invention is a thermochromic powder with model number WB-3665 produced by Lijin Technology Co., Ltd. The PDMS material doped with thermochromic material can change from red to colorless when the environment is at 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C and 75°C, and has an obvious thermochromic response.

[0055] The above-mentioned translucent silicone layer is coated with copper powder to form a first reflective layer 8 (thickness of 0.05mm). The above-mentioned first reflective layer is used to reflect light and identify tiny textures. The above-mentioned first reflective layer is coated with a second reflective layer 9 (made of copper powder and melanin). Ecoflex 00-30 silicone rubber, with a thickness of 0.3 mm), the second reflective layer is used to isolate ambient light and protect the sensor.

[0056] The anatomical diagram of the tactile sensing layer of the tactile sensor is as follows: Figure 6 As shown, the preparation details are as follows. The present invention uses silicone with excellent physical properties such as flexibility and tensile strength as the base material. In order to simulate the tactile perception of real skin, a material with a hardness similar to that of the real skin is selected. DRSGJ02 silicone (Shore hardness 5) is used to synthesize the required translucent elastomer. The thickness of the elastomer is set to 2mm to ensure that it has both good flexibility and fast rebound properties. First, DRSGJ02 A and B type silicones are poured into a beaker at a mass ratio of 1:1 and mixed, and slowly stirred in one direction for two minutes to form a prepolymer. Then, the prepolymer is placed in a vacuum barrel and vacuumed for 5 minutes to allow the bubbles to completely escape from the mixture. The prepolymer is then poured into a 50×50×2mm high-temperature resistant nylon mold and placed in a 100℃ oven for 2 hours to obtain a translucent elastomer, that is, a translucent silicone layer 6. Then, a laser cutting machine is used to cut out a 3*3 matrix of circular holes with a radius of 2.5mm and a depth of 0.1mm (the spacing between adjacent circular holes is 6.2mm). Subsequently, the thermochromic powder of WB-3665 having obvious thermochromic response at 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C and 75°C was mixed with PDMS prepolymer and curing agent (hydrogen silicone oil) at a mass ratio of 3:10:1 to obtain a PDMS prefabricated liquid that can change color at different temperatures. The PDMS prefabricated liquid with the thermochromic material was mixed according to the Figure 9 The arrangement is poured into 9 grooves respectively and heated at 80°C for 1 hour to cure, and a PDMS layer with thermochromic material can be obtained. Then, an appropriate amount of 400 mesh copper powder is poured on the elastomer and slowly scraped with a stirring rod until they are evenly spread over the entire surface to form a matte surface that is sensitive to three-dimensional shape perception. Since the silicone material used to make the elastomer is oily, the material will naturally adhere to the surface. Then, the excess copper powder is removed by repeatedly scraping the surface of the elastomer to ensure that the surface copper powder is evenly coated and light cannot pass through. The preparation of the second reflective layer uses copper powder, silicone ( The second reflective layer coating is made from a mixture of Ecoflex 00-30 silicone (Shore A30) and melanin. Copper powder, silicone, and melanin are mixed in a mass ratio of 1:26:1 and slowly stirred in the same direction for 2 minutes. The mixture is then vacuum-degassing for 5 minutes. The combination of copper powder and silicone ensures that the second reflective layer combines both sensing and protection functions, improving surface resolution and forming a stable chemical bond between the reflective film layers, reducing the risk of external material shedding during use. The addition of melanin further reduces the penetration of ambient light. To ensure a complete and even distribution of the second reflective layer during the coating process, a 0.3mm four-sided film applicator is used. A sufficient amount of the mixed material is applied as evenly as possible to the elastomer. The applicator is then used to gently remove excess material, leaving a film height of 0.3mm. After solidification, the film is cut and demolded to create the final tactile sensing skin.

[0057] Example 1

[0058] This embodiment is intended to verify the texture perception function of the sensor. This function constructs a mapping table between depth and pixel value by establishing a correspondence between pixel value and pressing depth. On this basis, the sensor can assign corresponding height information to each pixel in the image according to the mapping table, thereby generating a point cloud map. Subsequently, the point cloud data is gridded and smoothed using Gaussian filtering to remove noise and unclear details, further optimizing the data quality. Finally, the processed point cloud map is converted into a realistic three-dimensional model through three-dimensional reconstruction technology. This process effectively realizes the combination of texture recognition and height mapping, providing accurate data support for the perception of complex surface structures.

[0059] The specific process of surface texture reconstruction using sensors is as follows:

[0060] The first step is image acquisition. First, the visual-tactile sensor (with an image resolution of 480×640 pixels and a sampling frequency of 30Hz) is mounted on the fingertips of a Robotiq 3F-15 three-finger gripper. This gripper has a gripping force of 15N and an opening and closing range of 0-50mm. It is mounted on the flange of a Universal Robots UR5e six-axis collaborative robot arm. The UR5e robot arm has an 850mm reach, a load capacity of 5kg, a repeatability of ±0.03mm, and a working radius of 500mm. The visual-tactile sensor's USB 3.0 data cable, the Robotiq gripper's RS-485 communication cable, and the UR5e robot arm's Ethernet control cable are all connected to the control computer. The control computer uses an Intel Core i9-13980HX processor (24 cores, 32 threads, base frequency 1.6GHz, maximum turbo frequency 5.6GHz), equipped with 16GB of DDR5-4800MHz dual-channel memory and an NVIDIA GeForce RTX 4060 graphics card (8GB of GDDR6 video memory). Storage uses a 1TB NVMe SSD, running the Ubuntu 20.04LTS operating system and the ROS Noetic robotic operating system. This computer runs a control program that sends motion commands at a control frequency of 1000Hz, controlling the UR5e robotic arm to move at a linear speed of 5mm / s, driving the Robotiq gripper equipped with a visual tactile sensor to gradually approach the target object. In this example, a standard M2×3mm Phillips-head screw with a diameter of 2mm and a length of 3mm, made of 304 stainless steel, was used as the test object. When the silicone contact surface (thickness 2mm, Shore A hardness 20) of the visual tactile sensor contacts the M2 screw, the silicone layer produces a local deformation of about 0.2-0.8mm under the action of a contact force of 0.5N. At this time, the sensor's built-in 640×480 resolution CMOS camera captures the deformation image of the silicone surface in real time at a frame rate of 30fps, and the image data is transmitted to the computer at a speed of 480Mbps through the USB 3.0 interface for real-time processing and analysis. The contact detection response time of the entire system is less than 33ms, and the deformation measurement accuracy can reach 0.01mm, which can achieve high-precision visual tactile perception and real-time feedback control. When the visual tactile sensor contacts the screw, the silicone layer will deform. At this time, the deformation image of the silicone can be captured by the camera, such as Figure 7 The tactile reference image is captured when the sensor is not in contact with the object and represents the object's initial state. The tactile deformation image is captured by the camera after the sensor contacts the object and reflects the deformation caused by the contact between the silicone tactile device and the object.

[0061] The second step is image difference processing. A preset difference algorithm is used to perform pixel-by-pixel subtraction between the tactile reference image and the tactile deformation image, resulting in a tactile difference image and a tactile contact image. The tactile difference image is generated by performing a pixel-by-pixel subtraction between a 640×480 resolution tactile reference image and a tactile deformation image of the same resolution. This image clearly reflects the grayscale changes in the contact area of ​​the object. The grayscale difference typically ranges from 0 to 255, with larger differences indicating more significant deformation. The tactile contact image uses the opposite subtraction sequence: the tactile deformation image is subtracted from the tactile reference image, highlighting significant changes in the contact area. The entire difference processing process, accelerated by CUDA on the RTX 4060 graphics card, keeps the single-frame image processing time within 2-3 milliseconds, ensuring real-time performance. Specifically, the tactile difference image is generated by subtracting the tactile reference image from the tactile deformation image, reflecting the grayscale changes in the object's deformation area; the tactile contact image is generated by subtracting the tactile deformation image from the tactile reference image, highlighting significant changes in the contact area.

[0062] The third step is point cloud generation and mapping construction. Based on the tactile reference image, tactile difference image and tactile contact image, the system extracts the three-dimensional spatial information of the deformation area through deep learning algorithms and stereo vision reconstruction technology, and generates high-density tactile point cloud data containing about 5000-15000 data points. Each point cloud data point contains X, Y, Z three-dimensional coordinate information (accuracy ±0.01mm) and the corresponding grayscale intensity value. Through statistical analysis and machine learning training of a large amount of experimental data, the system constructs a nonlinear mapping lookup table between grayscale change values ​​and pressing depth. The mapping table covers 1024 discrete depth levels in the depth range of 0-2mm, and each level corresponds to a specific grayscale change threshold. The cubic spline interpolation algorithm can achieve depth estimation with an accuracy of 0.001mm, generating tactile point cloud data such as Figure 8 By analyzing the point cloud data, a mapping table between grayscale change values ​​and pressing depth is constructed. This mapping table can be used to quantify grayscale changes at different depths, providing accurate data support for further tactile perception and depth recognition.

[0063] The software and protocols involved in the present invention are all well-known technologies.

[0064] Example 2

[0065] The main purpose of this embodiment is to verify the temperature sensing function of the sensor and test the temperature measurement range, response speed and recovery time of the temperature sensing layer.

[0066] The present invention selects materials with obvious thermochromic response at 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 70℃ and 75℃, such as Figure 9As shown, the temperature sensing range covers 35°C to 75°C, making it suitable for a variety of temperature monitoring scenarios in daily life. The selected thermochromic material undergoes a significant color change from red to colorless when the set temperature threshold is reached, providing excellent visual indication. Compared to other color-changing types, such as inter-color transitions, this "visible-implicit" color change is easier to identify and interpret with the naked eye, enhancing the intuitiveness and practicality of the application.

[0067] use HS5S heating furnace and TT-K-30-SLE Teflon K-type thermocouple temperature measuring device are used to build a sensor temperature response time and recovery time measurement platform. The K-type thermocouple is placed at the contact surface between the sensor and the heating furnace to obtain the temperature at the contact surface. The temperature is gradually increased from 30℃ to 80℃, and the color changes of the 9 grooves of the sensor are observed. Figure 10 As shown in the figure, when the corresponding temperature threshold is reached, the nine grooves fade in turn. Based on this phenomenon, the temperature of the contact object can be judged. The perceptible temperature range is 35℃ to 75℃, with a graduation value of 5℃. Figure 11 As shown, the temperature is raised to above 30°C, the moment t0 when the temperature reaches 30°C is recorded, and the moment t1 when the groove with a temperature threshold of 30°C fades is recorded, from which the temperature response time is t1-t0=0.1s, and then the temperature is lowered to below 30 degrees Celsius, the moment t2 when the temperature reaches 30°C is recorded, and the moment t3 when the groove with a temperature threshold of 30°C returns to its original color is recorded, from which the recovery time is t3-t2=0.2s.

[0068] Matters not covered by the present invention are known technologies.

Claims

1. A temperature measuring visual tactile sensor, characterized by: The sensor includes a main body, a main body shell and a detachable tactile sensing structure on the top thereof; The main body is the part below the light isolation ring in the 9DTact sensor, and a light uniforming film is added between the light isolation ring and the LED light board below it; The main body shell has a height matching that of the internal light isolation ring and is provided with slots at the front and back; The detachable tactile sensing structure comprises a detachable structural shell and a sensing layer; wherein the sensing layer is mounted on the inner top of the detachable structural shell; The sensing layer comprises a PDMS layer, a quartz glass layer, a translucent silicone layer, a PDMS layer doped with a thermochromic material, a first reflective layer, and a second reflective layer. The PDMS layer, the quartz glass window, and the translucent silicone layer are laminated together from bottom to top. The translucent silicone layer has nine circular grooves arranged in a matrix, each of which contains a PDMS layer doped with a thermochromic material. The first reflective layer covers the translucent silicone layer and the PDMS layer. The second reflective layer covers the first reflective layer. The PDMS layer doped with thermochromic material is composed of 9 discs distributed in a 3*3 matrix with a thickness of 0.1-0.2 mm. The material of each disc is a mixture of thermochromic material, PDMS prepolymer and curing agent in a mass ratio of 3:10:

1.

2. The temperature measuring visual tactile sensor according to claim 1, wherein: The thermochromic material is a thermochromic powder of model WB-3665 produced by Lijin Technology Co., Ltd.

3. The temperature measuring visual tactile sensor according to claim 1, wherein: The material and side length of the detachable structural shell are the same as those of the main shell. It has buckles at the front and back, which match the slots at the top of the main shell and are used for plugging and fixing on the main shell.

4. The temperature measuring visual tactile sensor according to claim 1, wherein: The light-homogenizing film is made of polycarbonate and has a thickness of 0.1 mm.

5. The temperature measuring visual tactile sensor according to claim 1, wherein: The thickness of the PDMS layer is 1 to 2 mm; The thickness of the quartz glass layer is 1.8 to 2.2 mm; The translucent silicone layer is silicone with a Shore hardness of 5.

6. The temperature measuring visual tactile sensor according to claim 1, wherein: The first reflective layer is made of 400-mesh copper powder with a thickness of 0.05-0.07 mm. The thickness of the second reflective layer is 0.2-0.3 mm, and the second reflective layer is formed by mixing copper powder, silica gel and melanin in a mass ratio of 1:26:1.

Images