Controllable pre-stressed smart material based tactile sensor and manufacturing method

Abstract

The application discloses a controllable pre-stressed intelligent material-based tactile sensor and a manufacturing method. The sensor is mainly composed of a circular boss layer, a packaging layer, an intelligent polymer structure layer, a sensitive layer, an upper electrode layer, a substrate layer and a lower electrode layer, which are stacked from top to bottom. A plurality of through holes are arranged in the substrate layer, the upper electrode layer and the lower electrode layer are connected through the through holes, the upper electrode layer is connected with an external circuit, the number and arrangement position of the circular boss, the intelligent unit and the sensitive unit are the same and are aligned, the method comprises the steps of manufacturing the intelligent polymer structure layer, manufacturing the conductive resistance network, manufacturing the packaged sensor, using light or heat to stimulate the intelligent unit, and applying pre-stress to the sensitive unit after the deformation of the intelligent unit. The application applies local controllable pre-compression to the sensor unit by using the structured shape memory material, effectively reduces the dead zone range, and greatly improves the detection ability of the flexible sensor array to low pressure signals in unstructured scenes.

Description

Technical Field

[0001] This invention relates to a flexible tactile sensor in the field of intelligent robots, and in particular to a controllable prestressed intelligent material-based tactile sensor and its manufacturing method. Background Technology

[0002] As one of the key research areas of the 21st century, intelligent robots are a large and complex system engineering project. Tactile sensors, as data acquisition terminals in the interaction between intelligent robots and their environment, are a core component enabling intelligent robots to respond to changes in complex environments and have always been a key research direction in the field of robotics. Flexible tactile sensors can conform well to complex curved surfaces, meeting the needs of intelligent robots to acquire signals in unstructured and complex environments. They can detect signals of multiple dimensions and physical quantities, such as pressure, temperature, and slippage, and have very broad application prospects.

[0003] One of the key research directions for current flexible tactile sensors is achieving high performance, high precision, and signal detection under extreme conditions. Piezoresistive sensors, due to their stable signal characteristics and simple structure and circuit requirements, have become the preferred design principle for tactile sensors. However, for conventional piezoresistive tactile sensors, detecting minute signals near the zero point has always been a significant challenge. In engineering applications, 10% of the sensor's detection range is often used as the starting point for effective data. The detection "dead zone" problem near the zero point of piezoresistive sensors reduces the effective detection range of the sensor and also deprives it of the ability to detect minute signals. Furthermore, while facing the above problems, piezoresistive flexible tactile sensors also need to cope with complex unstructured operating conditions. Therefore, it is often necessary to comprehensively determine the signal detection range based on the sensor's location and layout, thus requiring customization of the actual operating range of the piezoresistive sensing unit. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a controllable pre-stressed shape memory polymer-based flexible tactile sensor array and its manufacturing method. This invention addresses the detection dead zone near zero point that is common in resistive flexible tactile sensors by applying locally controllable pre-compression to the sensor units using structured shape memory materials. This effectively reduces the dead zone range and significantly improves the ability of the flexible sensor array to detect low-pressure signals in unstructured environments.

[0005] The technical solution adopted in this invention is as follows:

[0006] I. A smart material-based tactile sensor with controllable prestress:

[0007] It is mainly composed of a circular boss layer, an encapsulation layer, a smart polymer structure layer, a sensitive layer, an upper electrode layer, a base layer, and a lower electrode layer stacked from top to bottom. The base layer has several vias, and the upper electrode layer and the lower electrode layer are connected through vias. The upper electrode layer is connected to an external circuit.

[0008] The circular boss layer and the smart polymer structure layer are provided with mutually cooperating protrusions. The sensitive layer is provided with sensitive units that cooperate with the protrusions. Through the cooperation between the circular boss layer, the smart polymer structure layer and the sensitive layer, the prestress of the sensitive unit can be changed under pressure. By adjusting the magnitude of the prestress of each sensitive unit, the range and detection range of each sensitive unit can be adjusted, thereby realizing the signal detection of the sensor in various working environments.

[0009] The circular boss layer is mainly formed by a number of circular bosses arranged in a rectangular array. The smart polymer structure layer is mainly formed by a number of smart units arranged in a rectangular array. The sensitive layer is mainly formed by a number of sensitive units arranged in a rectangular array at intervals. The number and arrangement positions of the circular bosses, smart units and sensitive units are the same and aligned. The circular bosses and smart units are respectively located in the middle of the upper and lower surfaces of the encapsulation layer. The upper and lower surfaces of the sensitive units are in contact with the smart units and the upper electrode layer, respectively.

[0010] The upper electrode layer and the lower electrode layer are respectively provided with a first circular electrode and a second circular electrode. Each of the first circular electrodes is connected to each other through a first electrode line, and each of the second circular electrodes is connected to each other through a second electrode line. The number of first circular electrodes and second circular electrodes is the same. Each of the second circular electrodes in the lower electrode layer is connected to a corresponding sensitive unit in the sensitive layer through a via in the substrate layer. The first electrode line in the upper electrode layer is connected to an external circuit. Each of the first circular electrodes in the upper electrode layer is provided with a sensitive unit on its upper surface.

[0011] Among the encapsulation layer, smart polymer structure layer, and sensitive layer, the encapsulation layer has the largest Young's modulus, while the sensitive layer has the smallest Young's modulus.

[0012] II. A method for manufacturing a sensor, comprising the following steps:

[0013] Step 1) Create the smart polymer structure layer and program its shape;

[0014] Step 2) Constructing a conductive resistor network:

[0015] Electrode lines and circular electrodes are sputtered onto the substrate layer by magnetron sputtering, and then the sensitive unit is bonded onto the substrate layer using copper powder conductive adhesive.

[0016] Step 3) After completing the encapsulation layer and the circular boss layer, the circular boss layer, the encapsulation layer, the smart polymer structure layer and the base layer with the conductive resistor network are bonded and encapsulated.

[0017] Step 4) Stimulate the smart units of the smart polymer structure layer with light or heat. After the smart units deform, they apply prestress to the sensitive units. By adjusting the intensity and duration of the stimulation received by each smart unit, the magnitude of the prestress of each sensitive unit can be adjusted, thereby adjusting the range and detection range of each sensitive unit.

[0018] Step 1) specifically involves: preparing a precursor for shape memory polymer (SMP); casting the shape memory polymer precursor into a mold; simultaneously curing the shape memory polymer precursor using an ultraviolet lamp to obtain a smart unit; removing the smart unit from the mold; and then heating it at a temperature greater than the glass transition temperature T of the smart unit. g The shape of the intelligent unit is adjusted under the specified temperature conditions. When the shape of the intelligent unit is adjusted to the preset shape, the intelligent unit is cooled and solidified.

[0019] The intelligent units in the intelligent polymer structure layer can respond to external light or heat stimuli and then apply controllable pre-compression to the sensitive unit; the sensitive layer and the electrode layer together form a sensing resistor network. By adjusting the degree of stimulation received by the intelligent unit, the magnitude of the pre-stress of each sensitive unit is controlled, thereby controlling the range, detection range, and small signal detection capability of the sensitive unit. The sensor of this invention has multiple independent sensitive units, enabling the sensor to detect pressure signals under different detection ranges.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. The piezoresistive flexible tactile sensor array of the present invention has an intelligent microstructure based on shape memory polymer. It achieves pre-compression of the sensitive unit inside the sensor through external excitation, reduces the detection dead zone of the sensor near zero point, endows the sensor array with detection capability under low pressure and small signal, improves the applicable working range of the sensor, and has great application potential in refined and highly sensitive industrial scenarios.

[0022] 2. Furthermore, the piezoresistive flexible tactile sensor array of the present invention can respond to local excitation, and the local excitation characteristics and intensity adjustable characteristics of the illumination endow the pre-compression of each unit of the sensor array with independent and controllable operation characteristics and no crosstalk, which expands the controllability of the pre-compression of the sensor array units and improves the sensor array's ability to detect weak signals in actual unstructured working environments. Attached Figure Description

[0023] Figure 1 This is a three-dimensional diagram showing the layered structure of the sensor array of the present invention.

[0024] Figure 2 (a) is a cross-sectional view of the sensing array of the present invention;

[0025] Figure 2 (b) is a cross-sectional view of each unit of the sensing array of the present invention under different external excitation intensities (excitation intensity increases from left to right).

[0026] Figure 3 (a) is a schematic diagram of the detection signal of the sensor array of the present invention without external excitation unit;

[0027] Figure 3 (b) is a schematic diagram of the detection signal of the low-intensity excitation unit of the sensing array of the present invention;

[0028] Figure 3 (c) is a schematic diagram of the detection signal of the high-intensity excitation unit of the sensing array of the present invention;

[0029] Figure 4 (a) is a schematic diagram of the upper electrode and sensitive layer structure of the sensing array of the present invention;

[0030] Figure 4 (b) is a schematic diagram of the lower electrode structure of the sensing array of the present invention;

[0031] Figure 4 (c) is a schematic diagram of the overall structure of the upper and lower electrodes of the sensing array of the present invention;

[0032] Figure 4 (d) is a schematic diagram of the overall structure of the conductive resistor network of the sensing array of the present invention;

[0033] Figure 5 This is a schematic diagram of the manufacturing process of the sensor of the present invention;

[0034] The figure shows: 1. Circular boss layer; 2. Encapsulation layer; 3. Microstructure layer; 4. Sensitive layer; 5. Upper electrode layer; 5-1. Circular electrode; 5-2. Electrode line; 6. Substrate layer; 7. Lower electrode layer; 7-1. Circular electrode; 7-2. Electrode line; 8. Via. Detailed Implementation

[0035] To make the objectives, technical solutions, and technical effects of this invention clearer, the invention will be further described below with reference to the accompanying drawings.

[0036] like Figure 1 As shown, the sensor is mainly composed of a circular boss layer 1, an encapsulation layer 2, a smart polymer structure layer 3, a sensitive layer 4, an upper electrode layer 5, a base layer 6, and a lower electrode layer 7 stacked from top to bottom. The base layer 6 has several vias 8. The upper electrode layer 5 and the lower electrode layer 7 are connected through the vias 8. The upper electrode layer 5 is connected to an external circuit.

[0037] The circular boss layer 1 and the smart polymer structure layer 3 are provided with mutually cooperating protrusions. The sensitive layer 4 is provided with sensitive units that cooperate with the protrusions. Through the cooperation between the circular boss layer 1, the smart polymer structure layer 3 and the sensitive layer 4, the prestress of the sensitive unit can be changed under pressure. By adjusting the magnitude of the prestress of each sensitive unit, the range and accuracy of each sensitive unit can be adjusted, thereby realizing the signal detection of the sensor in various working environments.

[0038] The circular boss layer 1 and the encapsulation layer 2 together form the upper encapsulation layer; the smart polymer structure layer 3 is specifically a shape memory polymer microstructure layer. The upper surface of the smart polymer structure layer 3 is tightly bonded to the lower surface of the encapsulation layer 2, and the lower surface of the smart polymer structure layer 3 is bonded to the sensitive unit in the sensitive layer 4; the sensitive units in the sensitive layer 4 are arranged at equal intervals and are tightly bonded to the substrate layer 6; the upper electrode layer 5 and the lower electrode layer 7 are printed on the upper and lower surfaces of the substrate layer 6 by magnetron sputtering. The upper electrode layer 5 and the lower electrode layer 7 are connected by vias 8 on the substrate layer 6. The electrode layers 5 and 7 together with the sensitive layer 4 form a conductive resistance network.

[0039] The circular boss layer 1 is mainly formed by several circular bosses arranged in a rectangular array. The smart polymer structure layer 3 is mainly formed by several smart units arranged in a rectangular array. The sensitive layer 4 is mainly formed by several sensitive units arranged in a rectangular array at intervals. The number and arrangement of the circular bosses in the circular boss layer 1, the smart units in the smart polymer structure layer 3, and the sensitive units in the sensitive layer 4 are the same and the arrangement positions are aligned vertically. The circular bosses and smart units are respectively located in the middle of the upper and lower surfaces of the encapsulation layer 2. The upper and lower surfaces of the sensitive units are in contact with the smart units and the upper electrode layer 5, respectively.

[0040] like Figure 4 (a)- Figure 4 As shown in (d), the upper electrode layer 5 and the lower electrode layer 7 are respectively provided with a first circular electrode 5-1 and a second circular electrode 7-1. The first circular electrodes 5-1 are connected to each other through a first electrode line 5-2, and the second circular electrodes 7-1 are connected to each other through a second electrode line 7-2. The number of first circular electrodes 5-1 and second circular electrodes 7-1 is the same. Each first circular electrode 5-1 and its corresponding second circular electrode (7-1) are paired to form nine pairs of electrode groups. Each second circular electrode 7-1 in the lower electrode layer 7 is connected to a corresponding sensitive unit in the sensitive layer 4 through a via 8 in the base layer 6. The first electrode line 5-2 in the upper electrode layer 5 is connected to an external circuit. The upper surface of each first circular electrode 5-1 in the upper electrode layer 5 is provided with a sensitive unit, that is, each sensitive unit is connected to a pair of electrode groups.

[0041] The upper electrode layer 5 and the lower electrode layer 7 are also provided with conductive electrodes. Each conductive electrode in the upper electrode layer 5 is connected to a corresponding conductive electrode in the lower electrode layer 7 through a via 8 in the base layer 6.

[0042] In the encapsulation layer 2, the smart polymer structure layer 3, and the sensing layer 4, at the sensor's operating temperature,

[0043] The Young's modulus of the encapsulation layer 2 is the largest, the Young's modulus of the sensing layer 4 is the smallest, and the Young's modulus of the smart polymer structure layer 3 is located within the range of the Young's modulus of the encapsulation layer 2 and the sensing layer 4.

[0044] Each circular protrusion layer 1, together with its corresponding intelligent unit and sensitive unit, forms a force transmission component. The circular protrusions of the circular protrusion layer 1 correspond one-to-one with the intelligent units of the intelligent polymer structure layer 3. The circular protrusion layer 1 disperses the positive pressure applied to the sensor surface to each circular protrusion. Then, the intelligent unit concentrates the positive pressure at the corresponding circular protrusion and transmits it to the corresponding sensitive unit, forming a stress transmission chain of the force transmission component.

[0045] like Figure 2 (a)- Figure 2 As shown in (b), the intelligent polymer structure layer 3 is made of a shape memory polymer precursor, which is mainly composed of monomer components, low molecular weight polymers, crosslinking agents, initiators, and functional components in a certain proportion. The intelligent units of the intelligent polymer structure layer 3 can be stimulated by external light or heat, thereby generating a deformation response. The intelligent polymer structure layer 3 has both photothermal and photosensitive response functions. The intelligent polymer structure layer 3 has a surface microstructure, which needs to be heated to a temperature higher than the glass transition temperature T of the material before the sensor is fabricated. g The microstructure is reversibly shaped and programmed. The programmed microstructure layer can recover under specific stimuli, thereby applying pre-compression to the sensitive unit.

[0046] The sensor sensing layer 4, together with the upper electrode layer 5 and the lower electrode layer 7, forms a conduction resistance network. By using light or heat to locally excite a single intelligent unit, pre-compression can be applied to the sensing unit 4, thereby achieving independent control of the pre-stress of each force transmission component in the sensor.

[0047] The main components of the circular boss layer 1, encapsulation layer 2, and base layer 6 are transparent or semi-transparent materials with high light transmittance, allowing light to penetrate the encapsulation layer 2 to excite the smart polymer structure layer 3. The encapsulation layer 2 is made of a material with a relatively large Young's modulus, and the structure is reinforced. The Young's modulus of the smart polymer structure layer 3 can vary at different temperatures. The material of the sensitive layer 4 is selected as a material with a relatively small Young's modulus. By controlling the structural strength and Young's modulus of each layer of the sensor, these three layers form a structural strength gradient from the outside to the inside, transferring the stress and strain released by the shape recovery of the smart polymer structure layer 3 to the sensitive unit.

[0048] The upper surface of the smart polymer structure layer 3 is tightly bonded to the lower surface of the encapsulation layer 2, with no relative movement. The lower surface of the smart polymer structure layer 3 is attached to the sensitive layer 4. Because the smart polymer structure layer 3 deforms when excited, the attachment point is not bonded. Figure 4 As shown, the sensitive units of the sensitive layer 4 are arranged in a 3×3 array with equal spacing of 5 mm and are tightly bonded to the substrate layer 6; the upper electrode layer 5 is arranged vertically, conducting 3 sensitive units in each column, and the lower electrode layer 7 is arranged horizontally, conducting 3 sensitive units in each row. The upper and lower electrode layers 5 and 7 are printed on the front and back sides of the substrate layer 6 by magnetron sputtering and are connected through vias 8 on the substrate layer. The upper and lower electrode layers 5 and 7 together with the sensitive layer 4 form a conductive resistance network. A scanning circuit selects one line in each row and column, with a total of 9 modes corresponding to 9 sensitive units.

[0049] The main components of the circular boss layer 1, encapsulation layer 2, and base layer 6 are transparent or translucent materials with high light transmittance, allowing light to penetrate the encapsulation layer to excite the shape memory polymer microstructure layer. The circular boss layer 1 and encapsulation layer 2 are made of polydimethylsiloxane (PDMS) modified with nano-silica, with a Young's modulus of 3.01 MPa. The smart polymer structure layer 3 uses a shape memory polymer precursor. The monomer component of the precursor raw material is tert-butyl acrylate (tBA), the crosslinking agent is aliphatic polyurethane diacrylate (AUD), the photoinitiator is (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (TPO), and the functional component is graphene, which are configured in a certain proportion. The sensitive layer 4 is made of conductive rubber with a Young's modulus of 1.49 MPa. The encapsulation layer 2 has a thickness of 0.2 mm, the smart polymer structure layer 3 has a thickness of 0.1 mm, the microstructure height is 0.65 mm, and the sensitive layer 4 has a thickness of 0.5 mm. By controlling the Young's modulus and structural strength of the three materials, a structural strength gradient that gradually weakens from the outside to the inside is achieved, and the stress released by the microstructure layer is transferred to the sensitive unit.

[0050] The circular boss has a bottom diameter of 5 mm and a height of 0.59 mm. The intelligent unit has a bottom diameter of 5 mm and a height of 1 mm. After shape programming, it forms a truncated conical structure with a diameter of 5 mm and a height of 0.65 mm. The circular boss and the intelligent unit combine to form the stress transmission chain of the sensor. First, the normal pressure is applied to the circular boss layer 1, and then distributed to the circular bottom surfaces of the nine distributed circular bosses. The normal pressure is then concentrated at the end of the corresponding intelligent unit and applied to the sensing unit. Furthermore, the correspondence between the intelligent unit and the sensing unit enables individual control of the prestress of each unit, such as... Figure 2 As shown in (b), the shape recovery response of a single intelligent unit can be achieved by local light or heat excitation. By adjusting the time and intensity of light or heat excitation, different degrees of shape recovery response of the intelligent unit can be achieved, thereby achieving different degrees of pre-compression of the sensitive unit, that is, changing the working range of the sensitive unit and reducing the dead zone.

[0051] The relationship between the pre-compression of the sensitive unit and the sensor detection dead zone is as follows: Figure 3 As shown in (a)-3(c), Figure 3 (a) is a sensitive unit without pre-compression. The relationship between the sensing signal of the sensitive unit and the normal pressure is shown in the figure. There is a certain region near the zero point where the unit is not sensitive to changes in normal pressure, which is the detection "dead zone" of the sensitive unit. Figure 3 (b) and Figure 3 (c) This section shows the signal changes of the sensitive element under low and high pre-compression conditions. Ideally, the signal outputs of different sensitive elements remain stable and consistent. When the deformation of the intelligent element applies pre-compression to the sensitive element, it is equivalently displayed on the coordinate system as the output signal shifts towards... x shaft and y The translation of the negative half-axis of the sensor results in a reduction in the dead zone. Within a certain range, the size of the dead zone is negatively correlated with the amount of pre-compression. However, the sensor's flexible structure also creates a detection dead zone. Figure 3 As shown in (c), the dead zone eventually cannot be reduced to zero, but remains within a very small range.

[0052] The manufacturing method of the present invention includes the following steps, such as: Figure 5 As shown:

[0053] Step 1) Fabricate the smart polymer structure layer 3 and program its shape;

[0054] A shape memory polymer (SMP) precursor is prepared, and the SMP precursor is cast into a mold while simultaneously curing it using a UV lamp to obtain a smart unit. The smart unit is then removed from the mold and heated to a temperature greater than the glass transition temperature T of the smart unit.g The shape of the intelligent unit is adjusted under the specified temperature conditions. When the shape of the intelligent unit is adjusted to the preset shape, the intelligent unit is cooled and solidified.

[0055] The temperature will be lowered to below the glass transition temperature T of the smart unit. g Then the external force was removed.

[0056] Step 2) Constructing a conductive resistor network:

[0057] Electrode lines and circular electrodes are sputtered on substrate 6 by magnetron sputtering, and then the sensitive unit is bonded on substrate 6 using copper powder conductive adhesive.

[0058] Step 3) The encapsulation layer 2 and the circular boss layer 1 are manufactured by casting and thermosetting, and the circular boss layer 1, the encapsulation layer 2, the smart polymer structure layer 3 and the base layer 6 with conductive resistance network are bonded and encapsulated.

[0059] Step 4) Use local light or heat to stimulate the smart units of the smart polymer structure layer 3. After the smart units deform, they apply prestress to the sensitive units. By adjusting the stimulation intensity and stimulation time of each smart unit, the magnitude of the prestress of each sensitive unit can be adjusted, thereby adjusting the range and detection range of each sensitive unit.

[0060] Specifically, by triggering the shape recovery response of the smart polymer structure layer 3, the smart polymer structure layer 3 applies prestress to the sensitive unit.

[0061] The specific working principle of the sensor array of this invention is as follows:

[0062] The working principle of this invention mainly consists of the following three aspects. The first aspect is as follows: Figure 3 As shown, pre-compressing the sensing element to different degrees effectively reduces the sensor's detection dead zone. Ideally, the sensor signal is stable and consistent. Pre-compressing the sensing element essentially applies an initial pressure to it, which cancels out the dead zone pressure range of the sensor's sensing element. In the coordinate system, this manifests as the output signal shifting towards... x shaft and y The negative half-axis of the axis is translated, which in turn reduces the dead zone of the sensor signal.

[0063] The second level utilizes the shape memory and self-driving properties of shape memory polymers to integrate the pre-compression strategy of the sensing unit into the structural design. For example... Figure 2As shown in (b), the microstructure (smart unit) made based on shape memory polymer can first program the shape of the microstructure to store potential energy, and then release the stored potential energy within a certain time under external thermal excitation, thereby triggering shape recovery. This phenomenon can be used to realize the pre-compression of the sensitive layer by releasing potential energy inside after the sensor is made.

[0064] At the third level, structural design achieves a one-to-one correspondence between the top circular boss layer 1, the intelligent polymer structure layer 3, and the sensitive layer 4, thus establishing a complete pressure transmission chain. Simultaneously, combined with the localizable excitation characteristics of light, it enables... Figure 3 The independent crosstalk-free pre-compression control of each force transmission component in the sensor shown ultimately enables the sensor array to detect low-pressure signals in unstructured scenarios.

[0065] The above specific embodiments are used to explain and illustrate the present invention, and not to limit the present invention. Any modifications and changes made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A smart material-based tactile sensor with controllable prestress, characterized in that: It is mainly composed of a circular boss layer (1), an encapsulation layer (2), a smart polymer structure layer (3), a sensitive layer (4), an upper electrode layer (5), a base layer (6), and a lower electrode layer (7) stacked from top to bottom. The base layer (6) has several vias (8). The upper electrode layer (5) and the lower electrode layer (7) are connected through the vias (8). The upper electrode layer (5) is connected to an external circuit. The circular boss layer (1) and the intelligent polymer structure layer (3) are provided with mutually cooperating protrusion structures. The sensitive layer (4) is provided with sensitive units that cooperate with the protrusion structures. Through the cooperation between the circular boss layer (1), the intelligent polymer structure layer (3) and the sensitive layer (4), the prestress of the sensitive unit can be changed under pressure. By adjusting the magnitude of the prestress of each sensitive unit, the range and detection range of each sensitive unit can be adjusted, thereby realizing the signal detection of the sensor in various working environments. The circular boss layer (1) is mainly formed by several circular bosses arranged in a rectangular array. The smart polymer structure layer (3) is mainly formed by several smart units arranged in a rectangular array. The sensitive layer (4) is mainly formed by several sensitive units arranged in a rectangular array at intervals. The number and arrangement positions of the circular bosses, smart units and sensitive units are the same and aligned. The circular bosses and smart units are respectively set in the middle of the upper and lower surfaces of the encapsulation layer (2). The upper and lower surfaces of the sensitive units are in contact with the smart units and the upper electrode layer (5) respectively. The smart units of the smart polymer structure layer (3) are stimulated by light or heat. After the smart units deform, prestress is applied to the sensitive units.

2. The intelligent material-based tactile sensor with controllable prestress according to claim 1, characterized in that: The upper electrode layer (5) and the lower electrode layer (7) are respectively provided with a first circular electrode (5-1) and a second circular electrode (7-1). Each first circular electrode (5-1) is connected to the other through a first electrode line (5-2), and each second circular electrode (7-1) is connected to the other through a second electrode line (7-2). The number of first circular electrodes (5-1) and second circular electrodes (7-1) is the same. The second circular electrode (7-1) in the lower electrode layer (7) is connected to a corresponding sensitive unit in the sensitive layer (4) through a via (8) in the base layer (6). The first electrode line (5-2) in the upper electrode layer (5) is connected to an external circuit. The upper surface of the first circular electrode (5-1) in the upper electrode layer (5) is provided with a sensitive unit.

3. The intelligent material-based tactile sensor with controllable prestress according to claim 1, characterized in that: Among the encapsulation layer (2), the smart polymer structure layer (3), and the sensitive layer (4), the encapsulation layer (2) has the largest Young's modulus, and the sensitive layer (4) has the smallest Young's modulus.

4. A method for manufacturing a sensor applicable to any one of claims 1-3, characterized in that, Includes the following steps: Step 1) Fabricate the smart polymer structure layer (3) and program the shape of the smart polymer structure layer (3); Step 2) Constructing a conductive resistor network: Electrode lines and circular electrodes are sputtered on the substrate layer (6) by magnetron sputtering, and then the sensitive unit is bonded on the substrate layer (6) using copper powder conductive adhesive. Step 3) Complete the encapsulation layer (2) and the circular boss layer (1), and bond and encapsulate the circular boss layer (1), the encapsulation layer (2), the smart polymer structure layer (3) and the base layer (6) with the conductive resistor network. Step 4) Stimulate the smart unit of the smart polymer structure layer (3) with light or heat. After the smart unit deforms, it applies prestress to the sensitive unit. By adjusting the intensity and duration of stimulation received by each smart unit, the magnitude of the prestress of each sensitive unit can be adjusted, thereby adjusting the range and detection range of each sensitive unit.

5. A method for manufacturing a sensor according to claim 4, characterized in that: Step 1) specifically refers to: A shape memory polymer (SMP) precursor is prepared, cast into a mold, and simultaneously cured using a UV lamp to obtain a smart unit. The smart unit is then removed from the mold and heated to a temperature greater than the glass transition temperature T of the smart unit. g The shape of the intelligent unit is adjusted under the specified temperature conditions. When the shape of the intelligent unit is adjusted to the preset shape, the intelligent unit is cooled and solidified.

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