A three-dimensional proximity-contact multimodal sensor for robotic dexterous manipulation

Abstract

The application discloses a three-dimensional proximity-contact multi-modal sensor for robot dexterous operation, which comprises, from bottom to top, a substrate layer, a circuit layer, a hollow elastic body, a magnetic electrode layer and a packaging layer arranged in sequence, the circuit layer is arranged on the substrate layer, a three-axis Hall sensor is arranged on the circuit layer, the hollow elastic body is arranged on the circuit layer, the magnetic electrode layer is attached to the hollow elastic body, and the packaging layer covers the surface of the magnetic electrode layer; the magnetic electrode layer comprises a plurality of magnetic electrodes which are independently arranged in an array, and the magnetic electrodes are coupled to each other to form a plurality of mutual-capacitance sensing units for proximity sensing; after the magnetic electrode layer is magnetized, a stable three-dimensional magnetic field distribution is formed in space, the hollow elastic body is used for elastic deformation when subjected to external load, and the magnetic electrode layer is driven to displace relative to the magnetic sensor on the circuit layer. The application realizes the synchronous integration of multi-directional proximity sensing and three-dimensional contact force sensing, and has the advantages of compact structure and high sensitivity.

Description

Technical Field

[0001] This invention specifically relates to a three-dimensional proximity-contact multimodal sensor for dexterous robot manipulation. Background Technology

[0002] When robots perform delicate grasping and dexterous manipulation tasks in unstructured dynamic environments, they urgently need to possess multiple perceptual abilities similar to humans. Among these, proximity sensing and force sensing are two crucial perceptual modalities. Proximity sensing can detect the spatial orientation and distance of an object before the robot's actuator actually makes contact with it, providing the robot with pre-contact information so that it can adjust its posture in advance to achieve compliant, collision-free approach. Force sensing, on the other hand, can monitor the magnitude, direction, and point of application of the contact force in real time during grasping and manipulation, preventing insufficient grasping force from causing the object to slip or excessive grasping force from causing damage. Currently, most robot sensors can only achieve single-modal perception. Combining proximity sensors and force sensors separately not only increases the complexity and size of the system, making it difficult to integrate into the limited finger space of a robot's dexterous hand, but also makes it difficult to achieve efficient and coherent "perception-decision-action" closed-loop control due to issues such as signal asynchrony and coordinate system inconsistencies. In addition, some existing multimodal sensors have limitations in their implementation methods. For example, some optical or vision-based proximity sensors are susceptible to interference from ambient light and are difficult to reuse the same sensing element with force sensors; while some magnetic induction-based force sensors typically employ solid magnetoelastic structures, which have high stiffness, resulting in limited force detection sensitivity, and the magnet and capacitive electrodes are usually discrete components, with low integration and miniaturization. Therefore, there is an urgent need in the field for a novel sensor that is compact, highly integrated, and capable of synchronously and in real-time sensing multi-directional proximity information and three-dimensional contact force information to truly enhance the robot's dexterity in dynamic environments. Summary of the Invention

[0003] The purpose of this invention is to provide a three-dimensional proximity-contact multimodal sensor for dexterous robot operation, which realizes the synchronous integration of multi-directional proximity sensing and three-dimensional contact force sensing, and has the advantages of compact structure, high sensitivity and comprehensive sensing dimensions.

[0004] The technical solution adopted in this invention is:

[0005] A three-dimensional proximity-contact multimodal sensor for dexterous robot operation includes a base layer, a circuit layer, a hollow elastomer, a magnetic electrode layer, and an encapsulation layer stacked sequentially from bottom to top. The circuit layer is disposed on the base layer and has a triaxial Hall sensor. The hollow elastomer is disposed on the circuit layer. The magnetic electrode layer is attached to the hollow elastomer. The encapsulation layer covers the surface of the magnetic electrode layer.

[0006] The magnetic electrode layer includes multiple independent magnetic electrodes arranged in an array. The overall structure of the magnetic electrode layer is a dome-shaped protrusion attached to the surface of a hollow elastic body in the shape of a truncated cone. Each magnetic electrode is coupled to form multiple mutual capacitance sensing units for proximity sensing.

[0007] The magnetic electrode layer is used to form a stable three-dimensional magnetic field distribution in space after being magnetized. The hollow elastic body is used to generate elastic deformation when subjected to external load, and to drive the magnetic electrode layer to move relative to the magnetic sensor on the circuit layer. The magnetic electrodes in the magnetic electrode layer are all directionally magnetized in the vertical direction to form a preset three-dimensional magnetic field distribution in space.

[0008] Preferably, the circuit layer further includes a multiplexer switch, which is connected to each magnetic electrode to poll and select the mutual capacitance sensing units of each directional channel in order to detect changes in the multi-directional mutual capacitance sensing units caused by the approach of an external object, thereby realizing three-dimensional proximity sensing.

[0009] Preferably, there are four magnetic electrodes. The four magnetic electrodes are independent of each other and are centrally symmetrically distributed in a cross-shaped radial pattern to ensure the consistency of the sensing signals in all directions. The four magnetic electrodes are coupled to each other through a multiplexer to form four mutual capacitance sensing units for proximity sensing.

[0010] The four mutual capacitance sensing units used for proximity sensing are the front channel proximity capacitor, the rear channel proximity capacitor, the left channel proximity capacitor, and the right channel proximity capacitor. The four magnetic electrodes are named front, rear, left, and right electrodes according to their orientation. Taking the front capacitance channel as an example, the left and right electrodes are short-circuited by a multiplexer switch to form one end of the mutual capacitance. The other end of the mutual capacitance is the front electrode. The capacitance between these two ends is the front channel proximity capacitor. The acquisition method of the other channels is similar. When a human body or metal object approaches from the front, the capacitance of the front channel changes more than that of the rear channel, while the capacitance changes are similar on both the left and right sides, thus achieving multi-directional proximity sensing. The rear channel proximity capacitance is formed by shorting the left and right electrodes together using a multiplexer, creating one end of a mutual capacitance. The other end of this mutual capacitance is the rear electrode, and the capacitance between these two ends is the rear channel proximity capacitance. The left channel proximity capacitance is formed by shorting the front and rear electrodes together using a multiplexer, creating one end of a mutual capacitance. The other end of this mutual capacitance is the left electrode, and the capacitance between these two ends is the left channel proximity capacitance. The right channel proximity capacitance is formed by shorting the front and rear electrodes together using a multiplexer, creating one end of a mutual capacitance. The other end of this mutual capacitance is the right electrode, and the capacitance between these two ends is the right channel proximity capacitance.

[0011] Preferably, the magnetic electrode leads are interconnected with the underlying circuit layer by filling the vertical conductive path with conductive silicone.

[0012] Preferably, the magnetic electrode has both high conductivity and high residual magnetic field strength. After being directionally magnetized in the vertical direction, the mutual capacitance electrode is reused as a magnetoelastic body to simultaneously sense the approach and contact of an object.

[0013] When the three-dimensional proximity-contact multimodal sensor is subjected to a normal force, the hollow elastic body and the magnetic electrode layer undergo compressive deformation along the Z-axis, resulting in an increase in the magnetic flux density along the Z-axis at the location of the triaxial Hall sensor, while the magnetic flux densities along the X and Y axes remain essentially unchanged. When the three-dimensional proximity-contact multimodal sensor is subjected to a tangential force, the hollow elastic body and the magnetic electrode layer undergo horizontal displacement along the X and / or Y axes, resulting in a change in the magnetic flux density along the X and / or Y axes at the location of the triaxial Hall sensor, while the magnetic flux density along the Z-axis remains essentially unchanged. By acquiring the three-dimensional magnetic flux density information from the triaxial Hall sensor, the magnitude and direction of the contact force in three-dimensional space can be obtained. By simultaneously acquiring the multi-directional proximity signals output by the multiplexer and the three-dimensional contact force signals output by the triaxial Hall sensor, multimodal perception of proximity and contact force is achieved, thereby enabling the robot to perform dynamic grasping and dexterous manipulation.

[0014] Preferably, a hollow elastomer is filled between the magnetic electrode layer and the circuit layer. The hollow elastomer is a truncated cone shape, narrow at the top and wide at the bottom, which provides structural support and elastic deformation space for the sensor.

[0015] Preferably, there are four magnetic electrodes. Based on electrode transfer and multiplexing, omnidirectional proximity sensing is achieved with the fewest electrode channels. The four magnetic electrodes are independent of each other and centrally symmetrically distributed in a cross-shaped radial pattern to ensure the consistency of sensing signals in all directions. The magnetic electrode layer can be tightly conformally fitted to the top plane and cylindrical surface of the hollow elastomer to form a hollow magnetoelastic body. Compared with a solid magnetoelastic body, the hollow magnetoelastic body has lower structural stiffness, greater deformation under the same contact force, and more significant change in the spatial magnetic field, thus improving the sensitivity of the three-dimensional contact force sensor.

[0016] The four magnetic electrodes are coupled together to form four mutual capacitance sensing units for proximity sensing. Specifically, the four magnetic electrodes are named front, back, left, and right electrodes according to their orientation. Taking the front capacitance channel as an example, the left and right electrodes are short-circuited by a multiplexer switch to form one end of the mutual capacitance. The other end of the mutual capacitance is the front electrode. The capacitance between these two ends is the proximity capacitance of the front channel. The acquisition method of the other channels is similar. When a human body or metal object approaches from the front, the capacitance of the front channel changes more than that of the rear channel, while the capacitance changes of the left and right channels are similar, thus realizing the multi-directional proximity sensing.

[0017] Preferably, the encapsulation layer, the base layer, and the hollow magnetic elastomer are insulating, flexible, and stretchable materials;

[0018] The insulating flexible stretchable material is selected from any one or a combination of several of polydimethylsiloxane (PDMS), Ecoflex, thermoplastic polyurethane (TPU), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and styrene-ethylene-butene-styrene block copolymer (SEBS).

[0019] Preferably, the magnetic electrode is made of a magnetoelectric composite material, which has both hard magnetic properties and high electrical conductivity.

[0020] Preferably, the magnetic electrode material is prepared by incorporating magnetoelectric particles with hard magnetic properties and high electrical conductivity into a polymer matrix (the polymer matrix can be such as TPU or PDMS) to form a magnetoelectric composite film; the incorporated magnetoelectric particles are NdFeB@Ag; the synthesized magnetoelectric composite film is NdFeB@Ag\TPU.

[0021] The preparation method of the magnetic electrode material includes the following specific steps:

[0022] Step (1) First, put NdFeB powder (3g) with an average particle size of 5um and polyvinylpyrrolidone (6g) with a relative molecular weight of 20000 into a reagent bottle, add 20mL of deionized water, and mechanically stir at 1500rpm for 30 minutes.

[0023] Step (2): Let the suspension stand for 10 minutes and remove the supernatant. Wash three times with deionized water and anhydrous ethanol, and finally dry in a vacuum oven at 70°C for 6 hours.

[0024] Step (3) Prepare 35 mL of silver ammonia solution: Slowly add 2 mol / L ammonia solution to 1 mol / L silver nitrate solution. First, a white precipitate AgOH is produced. Then, as the ammonia solution is added, the precipitate gradually dissolves until the solution is clear.

[0025] Step (4) Prepare 15ml glucose solution: Take 12g glucose powder and add 15mL deionized water and stir to dissolve;

[0026] Step (5) Take silver ammonia solution and put it into a brown reagent bottle. Add the cleaned and dried NdFeB powder, set the water bath temperature to 70 degrees Celsius, and heat with mechanical stirring at 1000 rpm for 30 min. Then add glucose solution dropwise and continue to heat with mechanical stirring at 800 rpm for 45 min.

[0027] After the reaction in step (6) is complete, the product NdFeB@Ag powder is separated using a magnet, and 50 mL of N,N-dimethylformamide and 6 mL of 0.1 mol / L NOBF4 are added. After gently shaking for 5 min, hexylamine dissolved in hexane is added. The solution is diluted with anhydrous ethanol and centrifuged at 2000 rpm.

[0028] Step (7) Wash the synthesized NdFeB@Ag three times with deionized water and anhydrous ethanol;

[0029] Finally, dry in a vacuum oven at 70°C for 6 hours.

[0030] The beneficial effects of this invention are:

[0031] In this invention, the magnetic electrode layer forms a stable three-dimensional magnetic field distribution in space after being magnetized. The hollow elastomer is used to generate elastic deformation when subjected to external load, and drives the magnetic electrode layer to displace relative to the magnetic sensor on the circuit layer. The magnetic electrodes in the magnetic electrode layer are all directionally magnetized perpendicular to the plane of the magnetic sensor to form a preset three-dimensional magnetic field distribution in space. Through multiple independent magnetic electrodes arranged in an array and the magnetic sensor of the circuit layer, the synchronous integration of multi-directional proximity sensing and three-dimensional contact force sensing is realized. It has the advantages of compact structure, high sensitivity and comprehensive sensing dimensions. The hollow elastomer structure has lower stiffness than the solid structure and greater deformation under the same external force, resulting in more significant changes in the spatial magnetic field and effectively improving the detection sensitivity of the three-dimensional contact force sensor. Attached Figure Description

[0032] Figure 1 This is an exploded view of a three-dimensional proximity-contact multimodal sensor for dexterous robot operation in an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram illustrating the working principle of a three-dimensional proximity-contact multimodal sensor used for dexterous robot operation in an embodiment of the present invention.

[0034] Figure 3 This invention relates to the formation and measurement principle of four mutual capacitance sensing units in a three-dimensional proximity-contact multimodal sensor for dexterous robot operation in this embodiment of the invention.

[0035] Figure 4 This is a signal response diagram of a three-dimensional proximity-contact multimodal sensor used for dexterous robot operation in an embodiment of the present invention under different magnitudes of normal contact force.

[0036] Figure 5 is a signal response diagram of a three-dimensional proximity-contact multimodal sensor for robot dexterity operation under different tangential forces in an embodiment of the present invention.

[0037] Figure 6 This is a signal response diagram of the front channel proximity capacitor and the rear channel proximity capacitor of the three-dimensional proximity-contact multimodal sensor used for robot dexterity operation in an embodiment of the present invention when it senses a human body approaching from the rear.

[0038] Figure 7 This is a signal response diagram of the left and right channel proximity capacitors of the three-dimensional proximity-contact multimodal sensor used for dexterous robot operation in an embodiment of the present invention when it senses a human body approaching from behind.

[0039] In the figure: 1-Encapsulation layer; 2-Magnetic electrode layer; 3-Hollow elastomer; 4-Circuit layer; 5-Base layer. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0041] In the description of this invention, it should be understood that if terms such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0042] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. They can refer to a mechanical connection or an electrical connection. They can refer to a direct connection or an indirect connection through an intermediate medium, and they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0043] Example 1

[0044] A three-dimensional proximity-contact multimodal sensor for dexterous robot operation includes a base layer 5, a circuit layer 4, a hollow elastomer 3, a magnetic electrode layer 2, and an encapsulation layer 1 stacked sequentially from bottom to top. The circuit layer 4 is disposed on the base layer 5 and has a triaxial Hall sensor. The hollow elastomer 3 is disposed on the circuit layer 4, and the magnetic electrode layer 2 is attached to the hollow elastomer 3. The encapsulation layer covers the surface of the magnetic electrode layer.

[0045] The magnetic electrode layer includes multiple independent magnetic electrodes arranged in an array. The overall structure of the magnetic electrode layer is a dome-shaped protrusion attached to the surface of a hollow elastic body in the shape of a truncated cone. Each magnetic electrode is coupled to form multiple mutual capacitance sensing units for proximity sensing.

[0046] The magnetic electrode layer is used to form a stable three-dimensional magnetic field distribution in space after being magnetized. The hollow elastic body 3 is used to generate elastic deformation when subjected to external load, and to drive the magnetic electrode layer 2 to move relative to the magnetic sensor on the circuit layer. The magnetic electrodes in the magnetic electrode layer are all directionally magnetized in the vertical direction to form a preset three-dimensional magnetic field distribution in space.

[0047] Furthermore, the circuit layer also includes a multiplexer switch, which is connected to each magnetic electrode to poll and select the mutual capacitance sensing units of each directional channel in order to detect changes in the multi-directional mutual capacitance sensing units caused by the approach of an external object, thereby realizing three-dimensional proximity sensing.

[0048] Furthermore, there are four magnetic electrodes. Based on electrode transfer multiplexing, omnidirectional proximity sensing is achieved with the minimum number of electrode channels. The four magnetic electrodes are independent of each other and are centrally symmetrically distributed in a cross-shaped radial pattern to ensure the consistency of sensing signals in all directions. The four magnetic electrodes are coupled to each other through a multiplexer switch to form four mutual capacitance sensing units for proximity sensing.

[0049] like Figure 3 As shown, the four mutual capacitance sensing units used for proximity sensing are the front channel proximity capacitance C. 前 The rear channel is close to capacitor C. 后 The left channel is close to capacitor C. 左 And the capacitor C near the right channel 右 The four magnetic electrodes are coupled together to form four mutual capacitance sensing units for proximity sensing. Specifically, the four magnetic electrodes are named front, rear, left, and right electrodes according to their orientation. Taking the front capacitance channel as an example, the left and right electrodes are short-circuited by a multiplexer, forming one end of the mutual capacitance. The other end of the mutual capacitance is the front electrode. The capacitance between these two ends is the front channel proximity capacitance C. 前The acquisition methods for the remaining channels are similar. When a human body or metal object approaches from the front, the front channel approaches the capacitor C. 前 Closer to capacitor C than the rear channel 后 The changes are more significant; the capacitance changes on both the left and right sides are similar, enabling the multi-directional proximity sensing. The rear channel proximity capacitance C... 后 To short-circuit the left and right electrodes using a multiplexer, forming one end of a mutual capacitance, the other end of which is the rear electrode. The capacitance between these two ends is the rear channel proximity capacitor; the left channel proximity capacitor C... 左 The process involves short-circuiting the front and rear electrodes using a multiplexer, forming one end of a mutual capacitance. The other end of this mutual capacitance is the left electrode. The capacitance between these two ends is the left channel proximity capacitor C. 左 The right channel is close to capacitor C. 右 The process involves short-circuiting the front and rear electrodes using a multiplexer, forming one end of a mutual capacitance. The other end of this mutual capacitance is the right electrode. The capacitance between these two ends is the right-side channel proximity capacitor C. 右 .

[0050] Furthermore, the magnetic electrode leads are interconnected with the underlying circuit layer by filling the vertical conductive path with conductive silicone.

[0051] Furthermore, the magnetic electrode has both high conductivity and high residual magnetic field strength. After being directionally magnetized in the vertical direction, the mutual capacitance electrode is reused as a magnetoelastic body to simultaneously sense the approach and contact of an object.

[0052] like Figure 2 As shown, when the three-dimensional proximity-contact multimodal sensor is subjected to a normal force, the hollow elastic body and the magnetic electrode layer undergo compressive deformation along the Z-axis, resulting in an increase in the magnetic flux density along the Z-axis at the location of the triaxial Hall sensor, while the magnetic flux density along the X and Y axes remains essentially unchanged. When the three-dimensional proximity-contact multimodal sensor is subjected to a tangential force, the hollow elastic body and the magnetic electrode layer undergo horizontal displacement along the X and / or Y axes, resulting in a change in the magnetic flux density along the X and / or Y axes at the location of the triaxial Hall sensor, while the magnetic flux density along the Z-axis remains essentially unchanged. By fitting the calibration data to the three-dimensional magnetic flux density information collected by the triaxial Hall sensor, the magnitude and direction of the contact force in three-dimensional space can be obtained. By simultaneously acquiring the multi-directional proximity signals output by the multiplexer and the three-dimensional contact force signals output by the triaxial Hall sensor, multimodal perception of proximity and contact force is achieved, thereby enabling the robot to perform dynamic grasping and dexterous manipulation. Figure 4As shown, when normal forces of 0.5N, 1N, and 1.5N are applied at certain frequencies in chronological order, the change in magnetic induction intensity (ΔBz) in the Z direction shows a gradually increasing trend, and the sensor exhibits good consistency under the same magnitude of normal force. Figure 5 As shown, the measurement results indicate that the tangential force coupling between the X-axis and Y-axis directions is small, and the normal force testing accuracy is high.

[0053] In this embodiment, the X-axis, Y-axis and Z-axis are perpendicular to each other, with the Z-axis perpendicular to the horizontal plane.

[0054] The signal response of a three-dimensional proximity-contact multimodal sensor used for dexterous robot manipulation when a human body approaches from behind. Figure 6 The signal responses of the front and rear capacitor channels during this process are shown. Figure 7 The signal responses of the left and right capacitor channels were demonstrated. The results showed that during the approach from the rear, the signal change of the rear capacitor channel was much greater than that of the front capacitor channel, while the signal changes of the left and right capacitor channels were not significantly different, exhibiting significant directionality, which enables accurate three-dimensional proximity sensing.

[0055] Example 2

[0056] Based on Example 1, the hollow elastomer was further defined, and the performance of Example 2 was even better after the definition was defined.

[0057] A hollow elastomer is filled between the magnetic electrode layer and the circuit layer. The hollow elastomer is shaped like a frustum, which is narrow at the top and wide at the bottom, providing structural support and elastic deformation space for the sensor.

[0058] Furthermore, there are four magnetic electrodes, which are independent of each other and centrally symmetrically distributed. The magnetic electrode layer as a whole is a dome-shaped protrusion with a cross-shaped radial pattern, which can conformally fit with the top plane and cylindrical surface of the hollow elastomer to form a hollow magnetic elastomer. Compared with a solid magnetic elastomer, the hollow magnetic elastomer has lower structural stiffness, greater deformation under the same contact force, and more significant change in the spatial magnetic field, thus improving the sensitivity of the three-dimensional contact force sensor.

[0059] Furthermore, the encapsulation layer, the substrate layer, and the hollow magnetic elastomer are insulating, flexible, and stretchable materials;

[0060] The insulating flexible stretchable material is selected from any one or a combination of several of polydimethylsiloxane (PDMS), Ecoflex, thermoplastic polyurethane (TPU), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and styrene-ethylene-butene-styrene block copolymer (SEBS).

[0061] Furthermore, the magnetic electrode is made of a magnetoelectric composite material, which has both hard magnetic properties and high electrical conductivity. After being magnetized, the hard magnetic material has a high remanent magnetization, forming an effective spatial magnetic field. At the same time, the magnetoelectric composite material has high electrical conductivity and can be used as a mutual capacitance electrode to achieve proximity detection.

[0062] Furthermore, the method for preparing the magnetic electrode material is as follows: incorporating magnetoelectric particles with hard magnetic properties and high electrical conductivity into a polymer matrix (the polymer matrix can be such as TPU or PDMS) to form a magnetoelectric composite film; the incorporated magnetoelectric particles are NdFeB@Ag; the synthesized magnetoelectric composite film is NdFeB@Ag\TPU.

[0063] The preparation method of the magnetic electrode material includes the following specific steps:

[0064] Step (1) First, put NdFeB powder (3g) with an average particle size of 5um and polyvinylpyrrolidone (6g) with a relative molecular weight of 20000 into a reagent bottle, add 20mL of deionized water, and mechanically stir at 1500rpm for 30 minutes.

[0065] Step (2): Let the suspension stand for 10 minutes and remove the supernatant. Wash three times with deionized water and anhydrous ethanol, and finally dry in a vacuum oven at 70°C for 6 hours.

[0066] Step (3) Prepare 35 mL of silver ammonia solution: Slowly add 2 mol / L ammonia solution to 1 mol / L silver nitrate solution. First, a white precipitate AgOH is produced. Then, as the ammonia solution is added, the precipitate gradually dissolves until the solution is clear.

[0067] Step (4) Prepare 15ml glucose solution: Take 12g glucose powder and add 15mL deionized water and stir to dissolve;

[0068] Step (5) Take silver ammonia solution and put it into a brown reagent bottle. Add the cleaned and dried NdFeB powder, set the water bath temperature to 70 degrees Celsius, and heat with mechanical stirring at 1000 rpm for 30 min. Then add glucose solution dropwise and continue to heat with mechanical stirring at 800 rpm for 45 min.

[0069] After the reaction in step (6) is complete, the product NdFeB@Ag powder is separated using a magnet, and 50 mL of N,N-dimethylformamide and 6 mL of 0.1 mol / L NOBF4 are added. After gently shaking for 5 min, hexylamine dissolved in hexane is added. The solution is diluted with anhydrous ethanol and centrifuged at 2000 rpm.

[0070] Step (7) The synthesized NdFeB@Ag was washed three times with deionized water and anhydrous ethanol, and finally dried in a vacuum oven at 70°C for 6 hours.

[0071] Working principle of the invention:

[0072] This invention belongs to the field of robot flexible sensing, and discloses a three-dimensional proximity-contact multimodal sensor for dexterous robot operation. It has a multi-layered structure, including: an encapsulation layer, a magnetic electrode layer, a hollow elastomer, a circuit layer, and a base layer. The magnetic electrode layer consists of four mutually coupled mutual capacitance electrodes, forming a cross shape. The hollow elastomer is generally frustum-shaped, narrower at the top and wider at the bottom. The cross-shaped planar magnetic electrodes are conformally attached to the top plane and surrounding cylindrical surfaces of the hollow elastomer, and interconnected with the underlying circuit layer through conductive vias. The circuit layer includes a Hall effect chip circuit and a multiplexed analog switch module, simultaneously transmitting the three-dimensional magnetic field and multi-channel capacitance signals to the signal receiving end. When the multimodal sensor is working, the mutual capacitance electrodes are connected to the capacitor multiplexed switch, generating a multi-directional high-frequency electric field. When a human body or metal object approaches the sensor from a certain direction, it couples with the electric field, causing the capacitance value of the corresponding channel to decrease, thereby achieving multi-directional proximity sensing. When an external force is applied to the multimodal sensor, the hollow elastic body deforms, causing a change in the spatial magnetic field generated by the surface magnetic electrodes. The change in the three-dimensional magnetic field strength at the center position is sensed by a triaxial Hall chip in the circuit layer, decoupling the magnitude of the triaxial contact force. This multimodal sensor achieves continuous multi-directional proximity and multi-axial force synchronous sensing based on the dual-function multiplexing of magnetic electrodes. Applying this invention, integrating this multimodal sensor into a robot actuator enables real-time and accurate acquisition of the spatial position and contact force information of the manipulated object, possessing significant scientific research value and engineering application significance for improving the robot's dynamic perception and dexterous manipulation capabilities.

[0073] By employing magnetic electrode materials with both high conductivity and hard magnetic properties, the capacitive sensing electrode and the magnetostrictive signal source are integrated into one, achieving functional reuse at the hardware level and greatly improving the sensor's integration. It can synchronously and in real-time acquire multi-directional proximity information and three-dimensional contact force information within a single device, providing robots with more comprehensive and continuous environmental interaction data. The hollow elastomer structure, compared to a solid structure, has lower stiffness and greater deformation under the same external force, resulting in more significant changes in the spatial magnetic field and effectively improving the detection sensitivity of the three-dimensional contact force sensor. The sensor's main structure is made of flexible materials, possessing good flexibility and stretchability, enabling it to adapt to complex contact surfaces and making it suitable for humanoid robot applications with high safety requirements.

[0074] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0075] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A three-dimensional proximity-contact multimodal sensor for dexterous robot manipulation, characterized in that: The system comprises, from bottom to top, a base layer (5), a circuit layer (4), a hollow elastomer (3), a magnetic electrode layer (2), and an encapsulation layer (1). The circuit layer (4) is disposed on the base layer (5) and a triaxial Hall sensor is provided on the circuit layer (4). The hollow elastomer (3) is disposed on the circuit layer (4), and the magnetic electrode layer (2) is attached to the hollow elastomer (3). The encapsulation layer covers the surface of the magnetic electrode layer. The magnetic electrode layer (2) is used to form a stable three-dimensional magnetic field distribution in space after being magnetized. The hollow elastomer (3) is used to generate elastic deformation when subjected to external load, and to drive the magnetic electrode layer (2) to move relative to the magnetic sensor on the circuit layer. The magnetic electrode layer (2) includes multiple independent magnetic electrodes arranged in an array. The overall structure of the magnetic electrode layer (2) is a dome-shaped protrusion attached to the surface of a hollow elastic body in the shape of a truncated cone. Each magnetic electrode is coupled to form multiple mutual capacitance sensing units for proximity sensing. The circuit layer also includes a multiplexer switch, which is connected to each magnetic electrode to poll and select the mutual capacitance sensing units of each directional channel in order to detect changes in the multi-directional mutual capacitance sensing units caused by the approach of an external object.

2. The three-dimensional proximity-contact multimodal sensor for dexterous robot operation as described in claim 1, characterized in that: There are four magnetic electrodes, which are independent of each other and centrally symmetrically distributed in a cross-shaped radial pattern. The four magnetic electrodes are coupled to each other to form four mutual capacitance sensing units for proximity sensing.

3. The three-dimensional proximity-contact multimodal sensor for dexterous robot operation as described in claim 2, characterized in that: The four mutual capacitance sensing units used for proximity sensing are the front channel proximity capacitor, the rear channel proximity capacitor, the left channel proximity capacitor, and the right channel proximity capacitor. The four magnetic electrodes are named the front electrode, the rear electrode, the left electrode, and the right electrode according to their orientation. The front channel proximity capacitor is formed by shorting the left and right electrodes together using a multiplexer, creating one end of a mutual capacitor. The other end of this mutual capacitor is the front electrode, and the capacitance between these two ends is the front channel proximity capacitor. Similarly, the rear channel proximity capacitor is formed by shorting the left and right electrodes together using a multiplexer, creating one end of a mutual capacitor. The other end of this mutual capacitor is the rear electrode, and the capacitance between these two ends is the rear channel proximity capacitor. The left channel proximity capacitor is formed by shorting the front and rear electrodes together using a multiplexer, creating one end of a mutual capacitor. The other end of this mutual capacitor is the left electrode, and the capacitance between these two ends is the left channel proximity capacitor. The right channel proximity capacitor is formed by shorting the front and rear electrodes together using a multiplexer, creating one end of a mutual capacitor. The other end of this mutual capacitor is the right electrode, and the capacitance between these two ends is the right channel proximity capacitor.

4. The three-dimensional proximity-contact multimodal sensor for dexterous robot operation as described in claim 1, characterized in that: The magnetic electrode leads are connected to the underlying circuit layer via vertical conductive paths filled with conductive silicone to achieve cross-layer interconnection.

5. The three-dimensional proximity-contact multimodal sensor for dexterous robot operation as described in claim 1, characterized in that: When the three-dimensional proximity-contact multimodal sensor is subjected to a normal force, the hollow elastic body and the magnetic electrode layer undergo compressive deformation along the Z-axis, resulting in an increase in the magnetic flux density along the Z-axis at the location of the triaxial Hall sensor, while the magnetic flux densities along the X and Y axes remain essentially unchanged. When the three-dimensional proximity-contact multimodal sensor is subjected to a tangential force, the hollow elastic body and the magnetic electrode layer undergo horizontal displacement along the X and / or Y axes, resulting in a change in the magnetic flux density along the X and / or Y axes at the location of the triaxial Hall sensor, while the magnetic flux density along the Z-axis remains essentially unchanged. The magnitude and direction of the contact force in three-dimensional space can be obtained by acquiring the three-dimensional magnetic flux density information from the triaxial Hall sensor. The multi-directional proximity signal output from the multiplexer and the three-dimensional contact force signal output from the triaxial Hall sensor are acquired simultaneously.

6. The three-dimensional proximity-contact multimodal sensor for dexterous robot manipulation as described in any one of claims 1 to 5, characterized in that: A hollow elastomer is filled between the magnetic electrode layer and the circuit layer. The hollow elastomer is shaped like a frustum, which is narrow at the top and wide at the bottom, providing structural support and elastic deformation space for the sensor. The magnetic electrode layer is a dome-shaped protrusion with a cross-shaped radial pattern, which can conformally fit the top plane and cylindrical surface of the hollow elastomer to form a hollow magnetic elastomer.

7. The three-dimensional proximity-contact multimodal sensor for dexterous robot operation as described in claim 1, characterized in that: The encapsulation layer, substrate layer, and hollow magnetic elastomer are all insulating, flexible, and stretchable materials. The insulating flexible stretchable material is selected from any one or a combination of several of the following: polydimethylsiloxane, Ecoflex, thermoplastic polyurethane, polyvinylidene fluoride-hexafluoropropylene, and styrene-ethylene-butene-styrene block copolymer.

8. The three-dimensional proximity-contact multimodal sensor for dexterous robot operation as described in claim 1, characterized in that: The magnetic electrode is made of a magnetoelectric composite material, which has both hard magnetic properties and high electrical conductivity.

9. The three-dimensional proximity-contact multimodal sensor for dexterous robot operation as described in claim 8, characterized in that: The magnetic electrode material is prepared by incorporating magnetoelectric particles with hard magnetic properties and high electrical conductivity into a polymer matrix to form a magnetoelectric composite film. The polymer matrix is ​​thermoplastic polyurethane or polydimethylsiloxane, the incorporated magnetoelectric particles are NdFeB@Ag, and the synthesized magnetoelectric composite film is NdFeB@Ag / thermoplastic polyurethane.

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