Multi-dimensional force touch sensing electronic skin and preparation method

Abstract

The invention discloses a multi-dimensional force tactile perception electronic skin and a preparation method thereof. In the method, a plurality of TMR elements are distributed on a flexible printed circuit board in an array; the silicone rubber substrate is adhered to the flexible printed circuit board on which a plurality of TMR elements are arrayed; preparing a neodymium iron boron-PDMS magnet block, wherein the neodymium iron boron-PDMS magnet block is formed by mixing neodymium iron boron magnetic particles and polydimethylsiloxane; a PDMS protective layer is prepared, a PDMS main agent and a curing agent are mixed and stirred according to the ratio of 5: 1, the mixture is put into an ultrasonic oscillator to be oscillated and then poured into a mold of the protective layer, then the mixture is put into a vacuum box together to be subjected to vacuum pumping treatment, ultrasonic oscillation is conducted, and finally the mixture is put into a curing box to be cured and cooled to obtain the PDMS protective layer; the PDMS protection layer and the neodymium iron boron-PDMS magnet block are bonded through the PDMS prepolymer and then laminated on the silicon rubber substrate, so that the neodymium iron boron-PDMS magnet block is located between the silicon rubber substrate and the PDMS protection layer.

Description

Technical Field

[0001] The present invention belongs to the field of electronic skin, in particular to a multi-dimensional force tactile perception electronic skin and a preparation method thereof. Background Art

[0002] Robots play an increasingly important role in human life, gradually moving from laboratories to factories and then to home life. An important indicator for evaluating the degree of intelligence that robots can become in human life is the robot's operational ability. As a medium for robots to interact with the outside world, tactile sensors enable robots to achieve self-perception and feedback operations, and better complete tasks such as object recognition, operation status judgment, and collision detection. In various daily operation tasks, sensors are required not only to be able to sense pressure, but also to be able to sense shear force and even torque. In addition, the sensor should also have a certain degree of flexibility and ductility, and be able to achieve the buffering protection of skin-like tissue. Existing magnetic films are usually integral films mixed with magnetic particles and polymers. This type of magnetic film usually has problems such as uneven magnetization and weak magnetic field strength, resulting in poor positioning accuracy, poor sensitivity and low resolution of arrayed sensors. Due to the uneven distribution and complexity of the magnetic field of the continuous magnetic film, the calibration of the sensor also becomes complicated. At present, electronic skin usually has problems such as only being able to detect pressure in a single direction, low sensitivity, difficult calibration, and high process requirements.

[0003] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention proposes a multi-dimensional force tactile perception electronic skin and a preparation method thereof, which has the characteristics of spatial multi-dimensional force dynamic and static recognition, high sensitivity and good flexibility.

[0005] The purpose of the present invention is to achieve the following technical solution: a method for preparing a multi-dimensional force tactile sensing electronic skin comprises:

[0006] A plurality of TMR elements are distributed in an array on a flexible printed circuit board;

[0007] The silicone rubber substrate is attached to a flexible printed circuit board having a plurality of TMR elements arrayed thereon;

[0008] preparing a NdFeB-PDMS magnet block, wherein the NdFeB-PDMS magnet block is formed by mixing NdFeB magnetic particles and polydimethylsiloxane;

[0009] Prepare the PDMS protective layer, mix the PDMS main agent and the curing agent in a ratio of 5:1, oscillate in an ultrasonic oscillator, pour into the mold of the protective layer, and then put them in a vacuum box for vacuum treatment, then perform ultrasonic oscillation, and finally put them in a curing box for curing and cooling to obtain the PDMS protective layer;

[0010] The PDMS protective layer and the NdFeB-PDMS magnet block are bonded by PDMS prepolymer and then laminated on the silicone rubber substrate, so that the NdFeB-PDMS magnet block is located between the silicone rubber substrate and the PDMS protective layer.

[0011] In the method for preparing a multi-dimensional force tactile sensing electronic skin, in preparing a NdFeB-PDMS magnet block, NdFeB magnetic particles and PDMS prepolymer are mixed in a ratio of 2:1, and placed in an ultrasonic mixer for stirring for 30-60 minutes to obtain the NdFeB-PDMS prepolymer; a layer of PDMS release agent is sprayed in the magnetic block mold, and then the NdFeB-PDMS prepolymer is poured into the magnetic block mold, and the magnetic block mold is placed in a constant magnetic field space device composed of two permanent magnets, and then the entire device is placed in a high-temperature curing box for curing and cooling, and finally magnetized along the thickness direction in the magnetic field space.

[0012] In the preparation method of the multi-dimensional force tactile sensing electronic skin, the magnetic block mold is placed in a constant 200mT magnetic field space device composed of two permanent magnets, and then the entire device is placed in a high-temperature curing box, cured at 80° for 2 hours, and then cooled at room temperature for 2 hours, and finally magnetized along the thickness direction in a 5T magnetic field space.

[0013] In the preparation method of the multi-dimensional force tactile sensing electronic skin, the PDMS main agent and the curing agent are mixed in a ratio of 5:1, then stirred with a glass rod for 10 minutes, and then oscillated in an ultrasonic oscillator for 2 minutes. The PDMS is then poured into the mold of the upper layer-protective layer, and then the whole is placed in a vacuum box for vacuum treatment, maintained at -0.09MPa for 2 minutes, and then ultrasonically vibrated for 5 minutes, and finally placed in a high-temperature curing box for constant temperature curing at 80° for 2 hours, and finally cooled at room temperature for 2 hours.

[0014] In the method for preparing the multi-dimensional force tactile sensing electronic skin, the PDMS prepolymer is prepared by mixing a PDMS main agent and a curing agent in a ratio of 8:1, and then putting the mixture into an ultrasonic stirrer for stirring to obtain the PDMS prepolymer.

[0015] A multi-dimensional force-tactile-sensing electronic skin is prepared according to the method for preparing the multi-dimensional force-tactile-sensing electronic skin.

[0016] In the multi-dimensional force tactile sensing electronic skin, 16 TMR elements are distributed in a 4×4 array on a flexible printed circuit board.

[0017] In the multi-dimensional force tactile sensing electronic skin, the size of the NdFeB-PDMS magnet block is 3mm×2.5mm×2mm, the thickness of the silicone rubber substrate is 4mm-5mm, and the TMR element is in the Z-axis magnetic sensitive direction with a size of 2.95mm×1.65mm×1.45mm.

[0018] In the multi-dimensional force tactile sensing electronic skin, the particle size of the NdFeB magnetic particles is 1 to 2 μm.

[0019] In the multi-dimensional force tactile sensing electronic skin, the NdFeB-PDMS magnet blocks are arranged in an N and S alternating arrangement.

[0020] Compared with the prior art, the present invention has the following advantages: the present invention uses neodymium magnet powder with large remanence and low intrinsic coercive force and PDMS with large elastic modulus to make magnetic blocks as magnetic field sources, and TMR elements with high sensitivity, low power consumption and insensitivity to temperature as sensing elements to form electronic skin. According to the output voltage characteristics and size of the magnetic sensitive element under different forces, the force / torque recognition and positioning are realized, and 16 TMR elements are welded on the FPCB with 4×4h, so that the sensor has a certain flexibility, which is convenient for the sensor to be attached to the manipulator. The magnetic blocks are arranged on the TMR elements to ensure that each TMR element can be in a higher magnetic field change range, thereby improving the sensitivity and resolution of the tactile sensor. The arrangement of a single magnetic block makes the TMR perception model simpler and easier to calibrate without considering other stray magnetic fields. Based on the continuity of the PDMS protective layer, even if the middle of the two magnetic blocks is subjected to external forces, the adjacent magnetic blocks will be deflected to a certain extent, thereby realizing higher resolution positioning of the force. The sensor uses a flexible and stretchable TPU substrate, which can be easily attached to various curved surfaces. The magnetic block is connected to the PDMS protective layer through the PDMS prepolymer. Since the polymer has the same functional groups, the magnetic block and the PDMS protective layer can be tightly connected. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] By reading the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present invention will become clear to those of ordinary skill in the art. The drawings in the specification are only for the purpose of illustrating the preferred embodiments and are not considered to be limitations of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work. Moreover, the same reference numerals are used to represent the same components throughout the drawings.

[0022] In the attached picture:

[0023] Figure 1 This is a schematic diagram of the entire structure of the electronic skin;

[0024] Figure 2 This is a schematic diagram of the change in the output voltage of the TMR element when the electronic skin is subjected to positive pressure;

[0025] Figure 3 This is a schematic diagram of the change in the output voltage of the TMR element when the electronic skin is subjected to a tangential force along the Y axis;

[0026] Figure 4 This is a schematic diagram of the change in the output voltage of the TMR element when the electronic skin is subjected to the tangential force of the X axis;

[0027] Figure 5 This is a schematic diagram of the change in output voltage of the TMR element when the electronic skin is subjected to in-plane torque;

[0028] Figure 6 This is a schematic diagram of the arrangement of the neodymium magnet powder-PDMS magnetic blocks of the electronic skin;

[0029] Figure 7 This is a schematic diagram of the layout of the TMR elements of the electronic skin.

[0030] The present invention is further explained below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0031] The specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0032] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the present invention. The scope of protection of the present invention shall be determined by the attached claims.

[0033] To facilitate understanding of the embodiments of the present invention, further explanation will be given below by taking specific embodiments as examples in conjunction with the accompanying drawings, and each of the accompanying drawings does not constitute a limitation on the embodiments of the present invention.

[0034] In one embodiment, Figures 1 to 7 As shown, a method for preparing a multi-dimensional force tactile sensing electronic skin includes:

[0035] A plurality of TMR elements 4 are distributed in an array on a flexible printed circuit board 5;

[0036] The silicone rubber substrate 3 is adhered to a flexible printed circuit board 5 having a plurality of TMR elements 4 arrayed thereon;

[0037] Prepare a NdFeB-PDMS magnet block 2, wherein the NdFeB-PDMS magnet block 2 is formed by mixing NdFeB magnetic particles and polydimethylsiloxane;

[0038] Prepare PDMS protective layer 1, mix and stir the PDMS main agent and the curing agent in a ratio of 5:1, oscillate in an ultrasonic oscillator, pour into a mold of the protective layer, and then put them in a vacuum box for vacuum treatment, then perform ultrasonic oscillation, and finally put them in a curing box for curing and cooling to obtain PDMS protective layer 1;

[0039] The PDMS protective layer 1 and the NdFeB-PDMS magnet block 2 are bonded by PDMS prepolymer and then laminated on the silicone rubber substrate 3, so that the NdFeB-PDMS magnet block 2 is located between the silicone rubber substrate 3 and the PDMS protective layer.

[0040] In a preferred embodiment of the method for preparing a multi-dimensional force tactile sensing electronic skin, in preparing the NdFeB-PDMS magnet block 2, NdFeB magnetic particles and PDMS prepolymer are mixed in a ratio of 2:1, and placed in an ultrasonic mixer for stirring for 30-60 minutes to obtain the NdFeB-PDMS prepolymer; a layer of PDMS release agent is sprayed in the magnetic block mold, and then the NdFeB-PDMS prepolymer is poured into the magnetic block mold, and the magnetic block mold is placed in a constant magnetic field space device composed of two permanent magnets, and then the entire device is placed in a high-temperature curing box for curing and cooling, and finally magnetized along the thickness direction under the magnetic field space.

[0041] In a preferred embodiment of the method for preparing a multi-dimensional force tactile sensing electronic skin, the magnetic block mold is placed in a constant 200mT magnetic field space device composed of two permanent magnets, and then the entire device is placed in a high-temperature curing box, cured at 80° for 2 hours, and then cooled at room temperature for 2 hours, and finally magnetized along the thickness direction in a 5T magnetic field space.

[0042] In a preferred embodiment of the method for preparing a multi-dimensional force tactile sensing electronic skin, the PDMS main agent and the curing agent are mixed in a ratio of 5:1, then stirred with a glass rod for 10 minutes, and then oscillated in an ultrasonic oscillator for 2 minutes. The PDMS is then poured into the mold of the upper layer-protective layer, and the whole is then placed in a vacuum box for vacuum treatment, maintained at -0.09MPa for 2 minutes, and then ultrasonically vibrated for 5 minutes, and finally placed in a high-temperature curing box for constant temperature curing at 80° for 2 hours, and finally cooled at room temperature for 2 hours.

[0043] In a preferred embodiment of the method for preparing the multi-dimensional force tactile sensing electronic skin, the PDMS prepolymer is mixed with a PDMS main agent and a curing agent in a ratio of 8:1, and is placed in an ultrasonic stirrer for stirring to obtain the PDMS prepolymer.

[0044] A multi-dimensional force-tactile-sensing electronic skin is prepared according to the method for preparing the multi-dimensional force-tactile-sensing electronic skin.

[0045] In the multi-dimensional force tactile sensing electronic skin, 16 TMR elements 4 are distributed on a flexible printed circuit board 5 in a 4×4 array.

[0046] In the multi-dimensional force tactile sensing electronic skin, the size of the NdFeB-PDMS magnet block 2 is 3mm×2.5mm×2mm, the thickness of the silicone rubber substrate 3 is 4mm-5mm, and the TMR element 4 is in the Z-axis magnetic sensitive direction and has a size of 2.95mm×1.65mm×1.45mm.

[0047] In the multi-dimensional force tactile sensing electronic skin, the particle size of the NdFeB magnetic particles is 1 to 2 μm.

[0048] In the multi-dimensional force tactile sensing electronic skin, the arrangement of the NdFeB-PDMS magnet blocks 2 is an N and S alternating arrangement.

[0049] In one embodiment, the multi-dimensional force tactile sensing electronic skin consists of five parts: a PDMS protective layer 1, a NdFeB-PDMS magnetic block, a silicone rubber substrate 3, a TMR element 4, and a flexible printed circuit board 5. It can fit well in the fingertips and palms of the manipulator, giving the robot the ability to sensitively perceive changes in the manipulated object. At the same time, it can also detect the edge shape of the object and the hardness of the object. The 4×4 TMR element 4 in the lower layer of the electronic skin can detect weak magnetic field changes, which are converted into changes in magnetic resistance value through the tunnel magnetoresistance effect, and then converted into electrical signals for output through the bridge circuit. The silicone rubber substrate 3 in the middle layer can be used as a cache layer to protect the sensor and the force displacement conversion matrix. According to actual needs, the range and resolution of the sensor can be changed by changing the elastic modulus of the matrix. When an external force acts on the PDMS protective layer, the PDMS protective layer and the magnetic bodies embedded in the protective layer move together to provide a changing magnetic field for the TMR magnetic sensitive element.

[0050] In one embodiment, the multi-dimensional force tactile sensing electronic skin includes a PDMS protective layer, a NdFeB-PDMS magnet block 2, a silicone rubber Ecoflex 00-30 middle layer, a TMR element 4 and a FPCB. Among them, 16 TMR elements 4 are distributed on the flexible PCB in a 4×4 array; a silicone rubber Ecoflex 00-30 middle layer is pasted on the flexible PCB; the PDMS protective layer and the magnet block together constitute the upper layer of the sensor. Based on neodymium magnet powder, polydimethylsiloxane and TMR magnetic sensitive elements, an electronic skin with force positioning, multi-dimensional force measurement, dynamic and static perception, and high-sensitivity detection is designed through arraying. When different external forces act on the electronic skin, the magnetic block will be displaced in space, thereby changing the distribution of the spatial magnetic field. The Z-axis tunnel magnetoresistive element is used as the detection part. The change of the magnetic field will cause the change of its internal magnetic resistance. The bridge circuit converts the change of resistance into an electrical signal for output. The magnetic sensitive elements at fixed positions show different change characteristics. By comprehensively judging the change trend and change value of the sixteen elements, the size, position and direction of the spatial multi-dimensional force can be recognized. The invention has the advantages of dynamic and static recognition of spatial multi-dimensional force, high sensitivity, good flexibility, etc.

[0051] The NdFeB-PDMS magnetic block is made of a mixture of NdFeB particles and polydimethylsiloxane, with a mass ratio of 2:1 and a size of 3mm×2.5mm×2mm. The multi-dimensional force tactile sensing electronic skin can sense skin surface pressure, shear force and torque perpendicular to the surface. The thickness of the Ecoflex 00-30 middle layer is 4mm-5mm.

[0052] The preparation method of the NdFeB-PDMS magnetic block comprises the following steps: mixing NdFeB magnetic particles and PDMS prepolymer in a ratio of 2:1, placing in an ultrasonic mixer and stirring for 30-60 minutes to obtain NdFeB-PDMS prepolymer; spraying a layer of PDMS release agent in the magnetic block mold, then pouring the NdFeB-PDMS prepolymer into the mold, placing the mold in a constant 200mT magnetic field space device composed of two permanent magnets, and then placing the entire device in a high-temperature curing box, curing at 80° constant temperature for 2 hours. Then cool at room temperature for 2 hours. Finally, magnetize along the thickness direction in a 5T magnetic field space. The particle size of the NdFeB magnetic particles is 1-2μm, that is, 2000 mesh neodymium magnet powder.

[0053] The production process of the PDMS protective layer includes the following steps: mixing the PDMS main agent and the curing agent in a ratio of 5:1, stirring with a glass rod for 10 minutes, then oscillating in an ultrasonic oscillator for 2 minutes, and then pouring the PDMS into the mold of the upper layer-protective layer, and then placing the whole in a vacuum box for vacuum treatment, and keeping it at -0.09MPa for 2 minutes. After that, ultrasonic vibration is carried out for 5 minutes, and finally placed in a high-temperature curing box, 80° constant temperature curing for 2 hours, and finally cooled at room temperature for 2 hours. The base material of the flexible printed circuit board 5 is polyimide, and the circuit is distributed on the flexible substrate.

[0054] The type and magnitude of the force the sensor is subjected to are determined by comparing the output results and output characteristics of each TMR.

[0055] In one embodiment, the multi-dimensional force tactile sensing electronic skin includes a PDMS protective layer 1, a neodymium magnet powder-PDMS magnetic block, a silicone rubber substrate 3, a TMR magnetic sensitive element and a flexible PCB. Among them, the bottom layer of sixteen TMR elements 4 are distributed on the flexible PCB in a 4×4 array; the silicone rubber substrate 3 is silicone rubber Ecoflex 00-30. The upper layer of sixteen rectangular neodymium magnet powder-PDMS magnetic blocks are embedded in the PDMS protective layer. The rectangular magnet is a mixture of neodymium iron boron particles and polydimethylsiloxane. When the external force acts on the protective layer, the PDMS protective layer undergoes a certain deformation, thereby driving the magnetic block in the PDMS protective layer to move. The TMR element 4 is fixed on the FPCB, which can sense the magnetic field changes caused by the displacement of the magnetic body and convert this magnetic field change into an electrical signal output. The corresponding relationship between displacement and magnetic field change is achieved through experimental calibration. The output electrical signal is uploaded to the host computer through a multi-channel dynamic acquisition system, and the host computer further classifies and processes the signal to realize the judgment of the size, position, direction and type of the contact force. The type, magnitude and direction of the force are determined as follows: When the sensor is subjected to a single-point pressure, the sensor at the corresponding pixel outputs a corresponding voltage signal, while other signals are almost not output, thereby realizing the positioning and identification of the contact point.

[0056] When the entire plane of the sensor is under pressure, the sensor is at the position with the largest magnetic field gradient and can output a higher voltage change. The direction of the voltage change is related to the direction of the magnet. When the N pole is close to the element, the output voltage of the single TMR element 4 decreases, and when the S pole is close to the element, the output voltage of the single TMR element 4 increases. Figure 2 When the entire plane of the sensor is subjected to a tangential force along the positive direction of the Y axis, Increase, Reduce, and The absolute value of the change is approximately equal, but The change is less than This is due to Only the N-pole magnet is away from the component. Not only is the S pole moving away, but the N pole is also moving closer, so The change in Only the N-pole magnet is away from the component. Only the S pole magnet above the component is far away, so the directions of change of the two are opposite and the voltage changes are similar.

[0057] When the entire plane of the sensor is subjected to a tangential force in the negative direction of the Y axis, Increase, Reduce, and The absolute value of the change is approximately equal, but The change in This is due to Only the S-pole magnet is away from the element. Not only is the N pole of the magnet moving away, but the S pole is also moving closer, so The change in Only the S-pole magnet is away from the component. Only the N-pole magnet is far away from the element, so the change directions of the two are opposite and the voltage changes are similar. When the entire plane of the sensor is subjected to a tangential force along the positive direction of the X axis, Increase, Reduce, and The absolute value of the change is approximately equal, but The change is less than This is due to Only the S-pole magnet is away from the element. Not only is the N pole of the magnet moving away, but the S pole is also moving closer, so The change in Only the S-pole magnet is away from the component. Only the N-pole magnet above the element is far away, so the change directions of the two are opposite and the voltage changes are similar. When the entire plane of the sensor is subjected to a tangential force along the negative X-axis, Reduce, Increase, and The absolute value of the change is approximately equal, but The change is greater than This is due to Only the N-pole magnet is away from the component. Not only is the S pole moving away, but the N pole is also moving closer, so The change in Only the N-pole magnet is away from the component. Only the S-pole magnet on the element is far away, so the change directions of the two are opposite and the voltage changes are similar. When the entire plane of the sensor is subjected to a counterclockwise torque along the Z axis, Increase, Reduce, and The absolute value of the change is approximately equal, but The change is less than This is due to The farther the element is from the deflection center, the greater the displacement. When the entire plane of the sensor is subjected to a clockwise torque along the Z axis, Reduce, Increase, and The absolute value of the change is approximately equal, but The change is less than This is due to The farther the element is from the deflection center, the greater the displacement. The amount of change is larger.

[0058] Although the embodiments of the present invention are described above in conjunction with the accompanying drawings, the present invention is not limited to the above specific embodiments and application fields, and the above specific embodiments are only illustrative and instructive, rather than restrictive. A person of ordinary skill in the art can also make many forms under the guidance of this specification and without departing from the scope of protection of the claims of the present invention, all of which belong to the protection of the present invention.

Claims

1. A method for preparing a multi-dimensional force-tactile sensing electronic skin, characterized in that: It includes the following steps: A plurality of TMR elements are distributed in an array on a flexible printed circuit board; The silicone rubber substrate is attached to a flexible printed circuit board having a plurality of TMR elements arrayed thereon; preparing a NdFeB-PDMS magnet block, wherein the NdFeB-PDMS magnet block is formed by mixing NdFeB magnetic particles and polydimethylsiloxane; Prepare the PDMS protective layer, mix the PDMS main agent and the curing agent in a ratio of 5:1, oscillate in an ultrasonic oscillator, pour into the mold of the protective layer, and then put them in a vacuum box for vacuum treatment, then perform ultrasonic oscillation, and finally put them in a curing box for curing and cooling to obtain the PDMS protective layer; The PDMS protective layer and the NdFeB-PDMS magnet block are bonded by PDMS prepolymer and then laminated on the silicone rubber substrate, so that the NdFeB-PDMS magnet block is located between the silicone rubber substrate and the PDMS protective layer.

2. The method for preparing a multi-dimensional force tactile sensing electronic skin according to claim 1, characterized in that: Preferably, in preparing the NdFeB-PDMS magnet block, NdFeB magnetic particles and PDMS prepolymer are mixed in a ratio of 2:1, and placed in an ultrasonic mixer for stirring for 30-60 minutes to obtain the NdFeB-PDMS prepolymer; a layer of PDMS release agent is sprayed in the magnetic block mold, and then the NdFeB-PDMS prepolymer is poured into the magnetic block mold, and the magnetic block mold is placed in a constant magnetic field space device composed of two permanent magnets, and then the entire device is placed in a high-temperature curing box for curing and cooling, and finally magnetized along the thickness direction under the magnetic field space.

3. The method for preparing a multi-dimensional force tactile sensing electronic skin according to claim 2, characterized in that: The magnetic block mold is placed in a constant 200mT magnetic field space device composed of two permanent magnets, and then the entire device is placed in a high-temperature curing box, cured at 80° for 2 hours, and then cooled at room temperature for 2 hours. Finally, magnetization is performed along the thickness direction in a 5T magnetic field space.

4. The method for preparing a multi-dimensional force tactile sensing electronic skin according to claim 1, characterized in that: The PDMS main agent and curing agent were mixed in a ratio of 5:1, and then stirred with a glass rod for 10 minutes, followed by oscillation in an ultrasonic oscillator for 2 minutes. The PDMS was then poured into the mold of the upper layer - the protective layer, and the whole was placed in a vacuum box for vacuum treatment, maintained at -0.09MPa for 2 minutes, and then ultrasonically vibrated for 5 minutes, and finally placed in a high-temperature curing box for constant temperature curing at 80° for 2 hours, and finally cooled at room temperature for 2 hours.

5. The method for preparing a multi-dimensional force tactile sensing electronic skin according to claim 1, characterized in that: The PDMS prepolymer is prepared by mixing a PDMS main agent and a curing agent in a ratio of 8:1, and then putting the mixture into an ultrasonic stirrer for stirring to obtain the PDMS prepolymer.

6. A multi-dimensional force tactile sensing electronic skin, characterized in that: It is prepared according to a method for preparing a multi-dimensional force-tactile sensing electronic skin according to any one of claims 1-5.

7. The multi-dimensional force tactile sensing electronic skin according to claim 6, characterized in that: The 16 TMR elements are distributed on the flexible printed circuit board in a 4×4 array.

8. The multi-dimensional force tactile sensing electronic skin according to claim 6, characterized in that: The size of the NdFeB-PDMS magnet block is 3mm×2.5mm×2mm, the thickness of the silicone rubber substrate is 4mm-5mm, and the TMR element is in the Z-axis magnetic sensitive direction with a size of 2.95mm×1.65mm×1.45mm.

9. The multi-dimensional force tactile sensing electronic skin according to claim 6, characterized in that: The particle size of NdFeB magnetic particles is 1 to 2 μm.

10. The multi-dimensional force tactile sensing electronic skin according to claim 6, characterized in that: The arrangement of NdFeB-PDMS magnet blocks is N and S alternating arrangement.

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