阅读说明：本技术 一种触觉传感器及其制备方法及力和/或力矩的测量装置 (Tactile sensor, preparation method thereof and force and/or moment measuring device ) 是由 崔晶 冯凯明 王易捷 楚中毅 胡智凯 于 2021-09-02 设计创作，主要内容包括：本发明公开了一种触觉传感器及其制备方法及力和/或力矩的测量装置,其中,触觉传感器由上至下依次包括：上层基板、上层电极、电介质层、下层电极和下层基板,可用于感应正压力、剪切力和力矩。本发明通过设置镜像相对且阵列式对称分布的多对叉指电极作为上层电极及下层电极,实现了基于单层结构的多维力和/或力矩的高灵敏度感应,且提高了对法向正压力的空间分辨能力。通过采用压膜成型的方法阵列式扩展电介质层,降低了触觉传感器的制备成本,且简化了其制备工艺。通过将触觉传感器与处理器连接,利用处理器根据触觉传感器的传感信号确定受力类型,并计算得到相应的力和/或力矩的值,实现了对多维力和/或力矩的测量。(The invention discloses a touch sensor, a preparation method thereof and a force and/or moment measuring device, wherein the touch sensor sequentially comprises the following components from top to bottom: the upper substrate, the upper electrode, the dielectric layer, the lower electrode and the lower substrate can be used for sensing positive pressure, shearing force and moment. According to the invention, a plurality of pairs of interdigital electrodes which are opposite in mirror image and symmetrically distributed in an array manner are arranged as the upper electrode and the lower electrode, so that high-sensitivity induction of multi-dimensional force and/or moment based on a single-layer structure is realized, and the spatial resolution capability of normal positive pressure is improved. By adopting the film pressing molding method to expand the dielectric layer in an array manner, the preparation cost of the touch sensor is reduced, and the preparation process of the touch sensor is simplified. The touch sensor is connected with the processor, the processor is used for determining the stress type according to the sensing signals of the touch sensor, and corresponding force and/or moment values are obtained through calculation, so that the measurement of the multi-dimensional force and/or moment is realized.)

1. The utility model provides a tactile sensor which characterized in that, tactile sensor includes from top to bottom in proper order:

the top layer of the upper layer substrate is integrally coated with copper and is connected with a source shielding electrode;

the upper layer electrode is arranged at the bottom layer of the upper layer substrate and consists of a plurality of pairs of interdigital electrodes which are symmetrically distributed in an array manner; each pair of interdigital electrodes of the upper layer electrode comprises two first working electrodes; the two first working electrodes are respectively connected with the grounding electrode and the active shielding electrode;

the dielectric layer is composed of a plurality of dielectric blocks distributed in an array manner;

the lower layer electrode consists of a plurality of pairs of interdigital electrodes which are distributed in a mirror image opposite mode with the plurality of pairs of interdigital electrodes of the upper layer electrode; each pair of interdigital electrodes of the lower layer electrode comprises two second working electrodes; the two second working electrodes are respectively connected with two paths of signal electrodes led out by the digital signal processing chip; the upper electrode, the dielectric layer and the lower electrode together form a plurality of capacitors; the number of the capacitors is equal to the number of the first working electrodes or the second working electrodes;

the top layer is used for arranging the lower electrode, and the bottom layer is used for packaging the digital signal processing chip; the digital signal processing chip is used for acquiring capacitance value variation of the capacitors to obtain corresponding sensing signals, so that force and/or moment can be determined according to the sensing signals.

2. A tactile sensor according to claim 1, wherein the dielectric layer comprises 9 dielectric layers arranged in 3 x 3 matrix formThe silicon RTV silicon rubber is composed of rectangular blocks made of silicon RTV silicon rubber; the filling rate of the dielectric layer is 19%.

3. A touch sensor according to claim 1, wherein the upper and lower electrodes are each composed of 4 pairs of interdigitated electrodes symmetrically distributed in a 2 x 2 array.

4. The tactile sensor according to claim 3, wherein the interdigital electrodes are structurally divided into two types of transverse penetration and longitudinal penetration; in the pairs of interdigital electrodes of the upper layer electrode and the lower layer electrode, the interdigital electrodes which are transversely inserted and the interdigital electrodes which are longitudinally inserted are alternately distributed.

5. The tactile sensor according to claim 3, wherein the pairs of interdigitated electrodes of the upper layer of electrodes are aligned with the pairs of interdigitated electrodes of the lower layer of electrodes with a displacement of a set magnitude.

6. A tactile sensor according to claim 1, further comprising:

the FPC connector is welded on the lower surface of the lower substrate and is connected with the digital signal processing chip;

the adapter plate is welded on the lower surface of the lower-layer substrate and connected with the FPC connector.

7. A tactile sensor according to claim 1, wherein the upper substrate is a four-layer plate; the upper substrate sequentially comprises from top to bottom:

a first layer, a second layer, a third layer and a fourth layer;

the first layer is a top layer of the upper substrate; the fourth layer is the bottom layer of the upper substrate;

the second layer is tightly attached to the first layer, integrally coated with copper and connected with a source shielding electrode;

the third layer is tightly attached to the second layer and the fourth layer, integrally covers copper, and is connected with a source shielding electrode.

8. A tactile sensor according to claim 1, wherein the lower substrate is a four-layer plate; the lower floor's base plate includes from top to bottom in proper order:

a fifth layer, a sixth layer, a seventh layer, and an eighth layer;

the fifth layer is the top layer of the lower substrate; the eighth layer is the bottom layer of the lower substrate;

the sixth layer is tightly attached to the fifth layer, integrally coated with copper and connected with a source shielding electrode;

the seventh layer is closely attached to the sixth layer and the eighth layer and used for wiring distribution.

9. A method for manufacturing a tactile sensor according to any one of claims 1 to 8, wherein the upper electrode is closely attached to the upper substrate to form an upper printed circuit board; the lower electrode is tightly attached to the lower substrate to form a lower printed circuit board; the preparation method comprises the following steps:

preparing an SMT steel mesh;

scraping a bonding layer on the upper surface of the lower electrode by using a blade to form a first bonding layer;

pouring a dielectric material on the first adhesive layer;

uniformly coating a medium material on the first adhesive layer;

after the surface coated with the medium material is vacuumized, placing the SMT steel mesh and covering a PET film;

compacting for 12 hours by using a heavy object after turning;

after the heavy object is taken down, turning over again, removing the PET film, taking down the SMT steel mesh, and forming a dielectric layer consisting of a plurality of dielectric blocks distributed in an array manner on the upper surface of the lower electrode;

scraping a bonding layer on the lower surface of the upper electrode by using a blade to serve as a second bonding layer, and positioning and integrating the upper printed circuit board and the lower printed circuit board together through pins;

compacting for 12 hours by using a heavy object;

and (5) taking down the weight to obtain the touch sensor.

10. A force and/or torque measuring device, wherein the measuring device comprises a tactile sensor according to any one of claims 1-8 and a processor;

the processor is connected with the digital signal processing chip and used for determining the stress type of the touch sensor according to the sensing signal, calculating corresponding capacitance value variation according to the sensing signal and the stress type, and obtaining the value of the force and/or the moment according to the corresponding relation between the capacitance value variation and the force and/or the moment.

Technical Field

The invention relates to the field of sensing devices, in particular to a touch sensor, a preparation method thereof and a force and/or moment measuring device.

Background

With the continuous development of robot intelligence, many daily works can be completed by replacing human with an intelligent robot, for example, the intelligent robot replaces human to enter forest fire for fire extinguishing, and a scalpel is held by hand for small-sized surgery for a patient, and the above environments mainly play a role in robot dexterity, which is based on the environment. The dexterous robot hand is composed of a plurality of fingers by simulating the hand of a human, and each finger can be regarded as a flexibly moving tandem robot.

In order to complete the tasks of grabbing and operating objects, a plurality of fingers are required to be coordinated, and the precondition of the coordination is that the dexterous hand can acquire enough environment information, such as shape and size, so as to adjust the grabbing state according to the acquired external environment information. Since the dexterous robot hand is to imitate human beings to complete the grabbing and releasing actions of various objects, it is necessary to acquire related sensing information. The touch sensor used on the dexterous fingertip of the robot can effectively acquire information such as the shape and the position of a contact object, is important for improving the actual operation capacity of the dexterous hand of the robot, can be called as a second pair of eyes of the robot, and has the most prominent characteristic of small volume.

The information of the related force of the fingertips when the robot is clever and clever to grasp can not be comprehensively reflected only by single-degree-of-freedom detection. In order to adapt to various external stimuli, the dexterous hand of the robot needs to have high-sensitivity sensing capability of normal positive pressure, shearing force, moment and other related information. In the research course of the touch sensor, the touch sensor formed by stacking a plurality of dielectric layers can only realize the detection of three-degree-of-freedom force and moment. However, the multi-path signal lines led out from the electrode array easily cause complex wiring, and influence of irrelevant capacitance signals exists, so that high precision of the sensor cannot be realized. Meanwhile, the array expansion of the electrodes and the dielectric layer can lead to large sensor volume, and the sensor is not easy to be applied to force perception of fingertips at the tail ends of dexterous hands of the robot.

Currently, the integration and sensitivity of touch sensors are limited by the existing media structures and fabrication processes. The touch sensor formed by stacking the multiple dielectric layers is complex in manufacturing process, the transfer dielectric layers need to be transferred by using the transfer film in the process of integrating the sensor through the steps of die reversing and the like, the transfer dielectric layers are difficult to avoid dragging in the transfer process, the dielectric layers are extremely easy to damage, the sensitivity detection of the sensor is finally influenced, time and labor are wasted, and the measuring range of the sensor is greatly limited due to the fact that the manufacturing process is immature and the problem that the bonding strength between the stacked structures of the multiple layers is not enough.

At present, single-point detection cannot meet the fingertip requirements of dexterous hands of robots, and in order to achieve more comprehensive reflection of actions such as insertion, pulling, rotation and screwing of objects, omnibearing array type extension is urgently needed to achieve detection of space multiple points.

In conclusion, the existing touch sensor has the problems of low sensitivity, large volume, complex and unreliable process manufacturing flow, incapability of meeting the requirement of single-point detection and the like, can not accurately reflect the relevant information of force when the robot captures the dexterous fingertip, and has the conditions of mistaken grasping, mistaken placement and the like. Therefore, the touch sensor applied to the smart fingertip of the robot is required to have the characteristics of multi-dimension, high sensitivity, miniaturization, simple and convenient process, high spatial resolution and the like.

Disclosure of Invention

The invention aims to provide a touch sensor, a preparation method thereof and a force and/or moment measuring device, which can improve the sensitivity and the spatial resolution of the touch sensor, reduce the preparation cost of the touch sensor, simplify the preparation process of the touch sensor and simultaneously realize the measurement of multi-dimensional force and/or moment.

In order to achieve the purpose, the invention provides the following scheme:

the utility model provides a tactile sensor, tactile sensor includes from top to bottom in proper order:

the top layer of the upper layer substrate is integrally coated with copper and is connected with a source shielding electrode;

the upper layer electrode is arranged at the bottom layer of the upper layer substrate and consists of a plurality of pairs of interdigital electrodes which are symmetrically distributed in an array manner; each pair of interdigital electrodes of the upper layer electrode comprises two first working electrodes; the two first working electrodes are respectively connected with the grounding electrode and the active shielding electrode;

the dielectric layer is composed of a plurality of dielectric blocks distributed in an array manner;

the lower layer electrode consists of a plurality of pairs of interdigital electrodes which are distributed in a mirror image opposite mode with the plurality of pairs of interdigital electrodes of the upper layer electrode; each pair of interdigital electrodes of the lower layer electrode comprises two second working electrodes; the two second working electrodes are respectively connected with two paths of signal electrodes led out by the digital signal processing chip; the upper electrode, the dielectric layer and the lower electrode together form a plurality of capacitors; the number of the capacitors is equal to the number of the first working electrodes or the second working electrodes;

the top layer is used for arranging the lower electrode, and the bottom layer is used for packaging the digital signal processing chip; the digital signal processing chip is used for acquiring capacitance value variation of the capacitors to obtain corresponding sensing signals, so that force and/or moment can be determined according to the sensing signals.

Optionally, the dielectric layers are uniformly arranged by 3-by-3 array of 9The silicon RTV silicon rubber is composed of rectangular blocks made of silicon rubber; the filling rate of the dielectric layer is 19%.

Optionally, the upper electrode and the lower electrode are each composed of 4 pairs of interdigitated electrodes symmetrically distributed in a 2 x 2 array.

Optionally, the interdigital electrodes are structurally divided into two types of transverse penetration and longitudinal penetration; in the pairs of interdigital electrodes of the upper layer electrode and the lower layer electrode, the interdigital electrodes which are transversely inserted and the interdigital electrodes which are longitudinally inserted are alternately distributed.

Optionally, there is a displacement of a set magnitude in alignment between the pairs of interdigitated electrodes of the upper layer electrode and the pairs of interdigitated electrodes of the lower layer electrode.

Optionally, the tactile sensor further comprises:

the FPC connector is welded on the lower surface of the lower substrate and is connected with the digital signal processing chip;

the adapter plate is welded on the lower surface of the lower-layer substrate and connected with the FPC connector.

Optionally, the upper substrate is a four-layer plate; the upper substrate sequentially comprises from top to bottom:

a first layer, a second layer, a third layer and a fourth layer;

the first layer is a top layer of the upper substrate; the fourth layer is the bottom layer of the upper substrate;

the second layer is tightly attached to the first layer, integrally coated with copper and connected with a source shielding electrode;

the third layer is tightly attached to the second layer and the fourth layer, integrally covers copper, and is connected with a source shielding electrode.

Optionally, the lower substrate is a four-layer plate; the lower floor's base plate includes from top to bottom in proper order:

a fifth layer, a sixth layer, a seventh layer, and an eighth layer;

the fifth layer is the top layer of the lower substrate; the eighth layer is the bottom layer of the lower substrate;

the sixth layer is tightly attached to the fifth layer, integrally coated with copper and connected with a source shielding electrode;

the seventh layer is closely attached to the sixth layer and the eighth layer and used for wiring distribution.

The invention also provides a preparation method of the touch sensor, wherein the upper layer electrode is tightly attached to the upper layer substrate to form an upper layer printed circuit board; the lower electrode is tightly attached to the lower substrate to form a lower printed circuit board; the preparation method comprises the following steps:

preparing an SMT steel mesh;

scraping a bonding layer on the upper surface of the lower electrode by using a blade to form a first bonding layer;

pouring a dielectric material on the first adhesive layer;

uniformly coating a medium material on the first adhesive layer;

after the surface coated with the medium material is vacuumized, placing the SMT steel mesh and covering a PET film;

compacting for 12 hours by using a heavy object after turning;

after the heavy object is taken down, turning over again, removing the PET film, taking down the SMT steel mesh, and forming a dielectric layer consisting of a plurality of dielectric blocks distributed in an array manner on the upper surface of the lower electrode;

scraping a bonding layer on the lower surface of the upper electrode by using a blade to serve as a second bonding layer, and positioning and integrating the upper printed circuit board and the lower printed circuit board together through pins;

compacting for 12 hours by using a heavy object;

and (5) taking down the weight to obtain the touch sensor.

The invention also provides a force and/or moment measuring device, which comprises the tactile sensor and a processor;

the processor is connected with the digital signal processing chip and used for determining the stress type of the touch sensor according to the sensing signal, calculating corresponding capacitance value variation according to the sensing signal and the stress type, and obtaining the value of the force and/or the moment according to the corresponding relation between the capacitance value variation and the force and/or the moment.

According to the specific embodiment provided by the invention, the invention discloses the following technical effects:

the invention provides a touch sensor, a preparation method thereof and a force and/or moment measuring device, wherein the touch sensor sequentially comprises the following components from top to bottom: the upper substrate, the upper electrode, the dielectric layer, the lower electrode and the lower substrate can be used for sensing positive pressure, shearing force and moment and obtaining corresponding sensing signals. According to the invention, a plurality of pairs of interdigital electrodes which are opposite in mirror image and symmetrically distributed in an array mode are arranged as the upper electrode and the lower electrode, so that high-sensitivity induction of five-degree-of-freedom force and/or moment based on a single dielectric layer structure is realized, and the spatial resolution capability of normal positive pressure is improved. By adopting the film pressing molding method to expand the dielectric layer in an array manner, the preparation cost of the touch sensor is reduced, and the preparation process of the touch sensor is simplified. The touch sensor is connected with the processor, the processor is used for determining the stress type according to the sensing signals sensed by the touch sensor, and corresponding force and/or moment values are calculated, so that the measurement of the multi-dimensional force and/or moment is realized.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

FIG. 1 is a schematic three-dimensional exploded view of a tactile sensor according to the present invention;

FIG. 2 is a top view of a lower electrode of a tactile sensor according to the present invention;

FIG. 3 is a schematic diagram illustrating the operation of a tactile sensor according to the present invention;

FIG. 4 is a circuit diagram of a digital signal processing chip and its peripheral circuits of a touch sensor according to the present invention;

FIG. 5 is a schematic diagram of the working principle of a force and/or moment measuring device provided by the present invention;

fig. 6 is a flowchart of a method for manufacturing a touch sensor according to the present invention.

Description of the symbols: the touch sensor comprises a touch sensor-1, an upper substrate-2, an upper electrode-3, a dielectric layer-4, a lower electrode-5 and a lower substrate-6.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention aims to provide a touch sensor, a preparation method thereof and a force and/or moment measuring device, which can improve the sensitivity and the spatial resolution of the touch sensor, reduce the preparation cost of the touch sensor, simplify the preparation process of the touch sensor and simultaneously realize the measurement of multi-dimensional force and/or moment based on a single dielectric layer structure.

The specific arrangement and the working principle of the tactile sensor provided by the invention are shown in embodiment 1, the specific arrangement and the working principle of the force and/or moment measuring device realized based on the tactile sensor are shown in embodiment 2, and the preparation method of the tactile sensor provided by the invention is shown in embodiment 3.

Example 1

Fig. 1 is a schematic three-dimensional explosion diagram of a tactile sensor according to the present invention, and as shown in fig. 1, the tactile sensor 1 sequentially includes an upper substrate 2, an upper electrode 3, a dielectric layer 4, a lower electrode 5, and a lower substrate 6 from top to bottom.

Specifically, the top layer of the upper substrate 2 is entirely coated with copper and is connected with a source shield.

The upper layer electrode 3 is arranged at the bottom layer of the upper layer substrate 2 and consists of a plurality of pairs of interdigital electrodes which are symmetrically distributed in an array manner; each pair of interdigital electrodes of the upper layer electrode 3 comprises two first working electrodes; the two first working electrodes are respectively connected with the grounding electrode and the active shielding electrode. According to the invention, the grounding electrode and the active shielding electrode are alternately distributed, so that the interference of stray capacitance is eliminated, and the sensitivity and accuracy of the touch sensor are improved.

The dielectric layer 4 is composed of a plurality of dielectric blocks distributed in an array. In this embodiment, the dielectric layer 4 is used as a sensing element of the touch sensor, and is preferably a layer of 9 rectangular small squares made of silicon rubber and uniformly arranged in a 3 × 3 array; the type of silicone rubber is preferably one having a high shear modulus of elasticitySilicone RTV Silicone rubber;the height of the dielectric layer 4 is about 80 μm; the filling rate of the dielectric layer 4 is 19%, and compared with a solid dielectric layer with the filling rate of 100% in the prior art, the touch sensor provided by the invention improves the sensitivity of the multi-dimensional force and/or torque induction by reducing the filling rate of the dielectric layer 4.

The lower electrode 5 consists of a plurality of pairs of interdigital electrodes which are distributed in a mirror image opposite manner with the plurality of pairs of interdigital electrodes of the upper electrode 3; each pair of interdigital electrodes of the lower electrode 5 comprises two second working electrodes; the two second working electrodes are respectively connected with two paths of signal electrodes led out by the digital signal processing chip; the upper electrode 3, the dielectric layer 4 and the lower electrode 5 together form a plurality of capacitors; the number of the capacitors is equal to the number of the first working electrodes or the second working electrodes.

The top layer of the lower substrate 6 is used for arranging the lower electrode 5; the bottom layer of the lower substrate 6 is used for packaging the digital signal processing chip; the digital signal processing chip is used for acquiring capacitance value variation of the capacitors to obtain corresponding sensing signals; the sensor signals are used to determine forces and/or torques in subsequent processing. According to the invention, the digital signal processing chip and the peripheral circuit thereof are integrated in the touch sensor, so that the digital signal processing chip and the peripheral circuit thereof can be used for realizing capacitance signal analog-to-digital conversion, signal active shielding and the like, and the influence of other interference signals is obviously reduced.

In this embodiment, the upper substrate 2 and the lower substrate 6 are made of FR-4 grade flame-retardant material. Meanwhile, the distance between the upper electrode 3 and the lower electrode 5 is limited by the current PCB processing process and is 100 μm. The touch sensor provided by the invention has the advantages that the two working electrodes of each pair of interdigital electrodes are closely arranged while the sensitivity is ensured as much as possible, and the electrical elements on the touch sensor are highly integrated and closely arranged, so that the problem of overlarge volume of the conventional touch sensor is solved, the touch sensor is miniaturized, and the touch sensor can be flexibly applied to smart finger tips.

In this embodiment, the upper electrode 3 is closely attached to the upper substrate 2 to form an upper printed circuit board; the lower electrode 5 is closely attached to the lower substrate 6 to form a lower printed circuit board.

In this embodiment, the size of the upper printed circuit board is 11mm × 11mm, and the size of the lower printed circuit board is 11mm × 24 mm. The upper layer electrode 3 and the lower layer electrode 5 are composed of 4 pairs of interdigital electrodes which are symmetrically distributed in a 2-by-2 array manner. But not limited to this, the sizes of the upper printed circuit board and the lower printed circuit board, and the number of pairs and arrangement of the interdigital electrodes can be adjusted according to actual needs. According to the invention, 2-by-2 array expansion is carried out on the upper electrode 3 and the lower electrode 5, the traditional single-point detection is replaced, and the high spatial resolution detection of 4 blocks of areas is realized, so that the captured information can be more comprehensively reflected.

In this embodiment, the interdigital electrodes are structurally divided into two types of transverse penetration and longitudinal penetration; in the pairs of interdigital electrodes of the upper layer electrode 3 and the lower layer electrode 5, the interdigital electrodes which are transversely inserted and the interdigital electrodes which are longitudinally inserted are alternately distributed.

The upper layer electrode 3 and the lower layer electrode 5 are exemplified by 4 pairs of interdigital electrodes distributed in 2 by 2 array, fig. 2 is a top view of the lower layer electrode 5 of the tactile sensor provided by the present invention, as shown in fig. 2, the upper left pair of interdigital electrodes is a longitudinal insertion structure, the lower left and upper right pairs of interdigital electrodes adjacent to the upper left pair of interdigital electrodes are both a transverse insertion structure, and so on, thereby realizing that the interdigital electrodes which are transversely inserted and the interdigital electrodes which are longitudinally inserted are alternately distributed.

Further, there is a small amount of displacement in alignment between the pairs of interdigital electrodes of the upper layer electrode 3 and the pairs of interdigital electrodes of the lower layer electrode 5 to generate a pair of differential signals between every two adjacent capacitor plates, thereby further improving the sensitivity of the touch sensor in the sensing direction of the shear force. The specific value of the displacement is obtained by adjusting according to a plurality of tests.

Preferably, the tactile sensor further comprises: FPC connector and keysets. Specifically, the FPC connector is soldered to the lower surface of the lower substrate 6 and connected to the digital signal processing chip; the adapter plate is welded on the lower surface of the lower-layer substrate 6 and connected with the FPC connector.

Compared with the mode that the touch sensor is connected with processors such as an external MCU singlechip and the like by DuPont wires in the prior art, the touch sensor is connected with the processors such as the external MCU singlechip and the like by welding the FPC connector and the adapter plate on the lower surface of the lower layer substrate 6, so that the touch sensor can be plugged in and pulled out of the processors such as the external MCU singlechip and the like at any time, and the operation is simpler and more convenient.

Further, the upper substrate 2 is a four-layer substrate; the upper substrate 2 sequentially comprises from top to bottom: a first layer, a second layer, a third layer and a fourth layer; specifically, the first layer is a top layer of the upper substrate 2; the fourth layer is the bottom layer of the upper substrate 2; the second layer is tightly attached to the first layer, and the whole body is coated with copper and is connected with a source shielding electrode; the third layer is closely attached to the second layer and the fourth layer, and the whole body is coated with copper and is connected with a source shielding electrode.

Further, the lower substrate 6 is a four-layer board; lower floor's base plate 6 includes from top to bottom in proper order: a fifth layer, a sixth layer, a seventh layer, and an eighth layer; the fifth layer is the top layer of the lower substrate 6; the eighth layer is the bottom layer of the lower substrate 6; the sixth layer is tightly attached to the fifth layer, and the whole body is coated with copper and is connected with a source shielding electrode; the seventh layer is closely attached to the sixth layer and the eighth layer and used for wiring distribution.

The touch sensor provided by the invention is based on a capacitive working mechanism, is the same for signal acquisition units of normal pressure, shearing force and bending moment, and is a three-layer sandwich structure consisting of an upper electrode 3, a dielectric layer 4 and a lower electrode 5. The signal acquisition unit of the touch sensor can change under the action of external force, so that the output capacitance value changes, and the magnitude of positive pressure Fz, tangential force Fx/Fy and moment Mx/My acting on the touch sensor can be sensed by acquiring the variable quantity of the capacitance of the signal acquisition unit.

9 dielectric layers 4 uniformly arranged in 3-by-3 arrayThe silicon RTV silicon rubber material is a rectangular block, and the working principle diagram of the touch sensor provided by the invention is shown in FIG. 3.

Under the action of a tangential force Fx in the x-axis direction or a shearing force Fy in the y-axis direction of the tactile sensor (as shown in (a) in fig. 3), a shearing electrode strip (namely, an upper electrode 3) of a bifurcate finger-shaped structure on an upper printed circuit board generates a tangential displacement delta L relative to a fixed electrode strip (namely, a lower electrode 5) on a lower printed circuit board, so that the facing area S of a capacitor plate of a signal acquisition unit is influenced, the output of a capacitance value C of the signal acquisition unit is changed, and the measurement of the tangential force can be realized by measuring the variation of the capacitance value. Wherein, the bifurcate finger-shaped structure electrode arranged on the upper layer printed circuit board can improve the sensitivity of the touch sensor to the shearing force by realizing the difference.

In order to improve the decoupling capability to the positive pressure during the detection of the shearing force, in this embodiment, the width of the interdigital electrode on the lower printed circuit board is increased, so that the total facing area of the upper electrode and the lower electrode is ensured to be unchanged when the touch sensor is subjected to the shearing force, and a good decoupling capability is realized. Mutual decoupling between the shearing forces perpendicular to each other (namely decoupling of the shearing force in the x-axis direction and the shearing force in the y-axis direction) can be realized by increasing the length of the interdigital electrodes.

Under the action of positive pressure Fz (as shown in (b) of FIG. 3), the dielectric layer 4 deforms, which results in a change in the distance d between the upper electrode 3 and the lower electrode 5, and thus the capacitance of the signal acquisition unit changes, and thus the measurement of the positive pressure can be realized by measuring the capacitance value change.

Under the action of the moment Mx in the x-axis direction or the moment My in the y-axis direction (as shown in (c) of FIG. 3), the capacitance values of the signal acquisition units will generate differences, and data calculation processing is performed by combining the capacitance value distribution difference and the distance between the capacitor plates, so that the moment measurement is realized.

Fig. 4 is a schematic diagram of a digital signal processing chip of a tactile sensor and peripheral circuits thereof according to the present invention. Table 1 shows the IIC addresses corresponding to the high and low levels of different ADD0 pins and ADD1 pins of the digital signal processing chip. As shown in fig. 4, in the present embodiment, the digital signal processing chip is preferably a digital capacitance conversion chip AD 7147.

TABLE 1 IIC addresses corresponding to high and low levels of different ADD0 pins and ADD1 pins of a digital signal processing chip

In actual operation, different addresses of the tactile sensors can be obtained by welding two of the four resistors R5, R6, R8 and R9, and by combining table 1, welding R5 and R9 can obtain ADD1 equal to 1 and ADD0 equal to 0, and the corresponding IIC address is 0101110; welding R5 and R8 to obtain ADD1 ═ 1 and ADD0 ═ 1, where the corresponding IIC address is 0101111; welding R6 and R9 can yield ADD1 ═ 0 and ADD0 ═ 0, when the corresponding IIC address is 0101100; welding R6, R8 yields ADD1 equal to 0 and ADD0 equal to 1, with the corresponding IIC address of 0101101.

As a specific implementation manner of this embodiment, the tactile sensors with different addresses are installed on the smart fingertip of the robot, the tactile sensors are connected with the MCU singlechip through the IIC protocol, and the MCU singlechip is used to identify the tactile sensors with different addresses to determine the corresponding fingertip of the finger, so that the grabbing pose can be adjusted according to the corresponding sensing information.

Example 2

The invention provides a force and/or moment measuring device which comprises a touch sensor and a processor.

The processor is connected with the digital signal processing chip and used for determining the stress type of the touch sensor according to the sensing signal output by the digital signal processing chip, calculating corresponding capacitance value variation according to the sensing signal and the stress type, and obtaining the value of the force and/or the moment according to the corresponding relation between the capacitance value variation and the force and/or the moment.

The stress types of the touch sensor comprise positive pressure in the z-axis direction, shearing force in the x-axis direction, shearing force in the y-axis direction, moment in the x-axis direction and moment in the y-axis direction.

The corresponding relation between the capacitance value variation and different types of forces and/or moments is obtained through a plurality of experimental measurements performed in advance.

As a specific implementation manner of this embodiment, the processor is preferably an MCU single chip, but is not limited thereto, and may be adjusted according to actual needs.

Fig. 5 is a schematic view of the working principle of the force and/or moment measuring device provided by the invention. As shown in fig. 5, for example, the upper electrode and the lower electrode of the tactile sensor provided by the present invention are composed of 4 pairs of interdigital electrodes symmetrically distributed in 2 × 2 array, the digital signal processing chip is a digital capacitance conversion chip, and the processor is an MCU single chip microcomputer, 8 working electrodes in the 4 pairs of interdigital electrodes in the lower layer are respectively connected to 8 channels of the digital capacitance conversion chip, and then communicate with the MCU single chip microcomputer through an IIC (i.e., I2C) protocol, and the MCU single chip microcomputer is used to read and process the variation of the sensing signal output by each working electrode in real time, so as to finally obtain the corresponding force and/or torque value.

Because the output signal of digital capacitance conversion chip is the count number, consequently, the MCU singlechip needs to utilize specific formula to convert digital capacitance conversion chip output count number into the capacitance value, and specific formula is as follows:

wherein, C_outIndicating the converted capacitance value and N the number of counts.

Further, in the early test process, the MCU singlechip can also utilize a TTL-USB converter to transmit the obtained data of the capacitance variation to an upper computer through USART communication, and a computer serial port is utilized to read the data in real time and record the relative capacitance variation of Fz, Fx, Fy, Mx and My. And then, the corresponding relation between the capacitance value and the force (namely the corresponding relation between the capacitance value variation and different types of forces and/or moments) is obtained by fitting the capacitance value variation and the corresponding acting force variation. By storing the corresponding relation between the capacitance value and the force in the MCU singlechip, the force can be reversely calculated according to the sensing signal and the corresponding relation between the capacitance value and the force. In the actual use process, the upper computer can acquire the change of the acting force in real time, so that the grabbing condition of the dexterous hand of the robot is reflected.

As a specific implementation manner of this embodiment, the method for determining the force type of the touch sensor by the processor and calculating the corresponding capacitance variation according to the sensing signal and the corresponding force type is as follows:

taking the example that the upper electrode and the lower electrode of the tactile sensor provided by the present invention are all 4 pairs of interdigitated electrodes symmetrically distributed in a 2 x 2 array, as shown in fig. 2, C1 to C8 respectively represent capacitance values of capacitors where 8 working electrodes in the lower electrode of the tactile sensor are located.

When the tactile sensor is subjected to normal positive pressure, C1, C2, C3, C4, C5, C6, C7 and C8 all change, and the total capacitance value change amount of the tactile sensor is equal to the sum of 8 capacitance value change amounts, namely Δ C ═ Δ (C1+ C2+ C3+ C4+ C5+ C6+ C7+ C8).

When the touch sensor is subjected to a shearing force in the x-axis direction, the facing areas of the upper and lower electrode plates of the capacitors C2, C6, C4 and C8 are changed, so that the capacitance value is changed, and the facing areas of the upper and lower electrode plates of the capacitance values of the other 4 capacitors are unchanged, so that the capacitance value is unchanged.

Meanwhile, since C2 and C6 form a pair of interdigital capacitors and C4 and C8 form a pair of interdigital capacitors, C2 and C6 form a pair of differential signals, and C4 and C8 form a pair of differential signals. Therefore, the total capacitance value change amount of the tactile sensor under the action of the shear force in the x-axis direction is equal to (the capacitance change amount of C2-C6) + (the capacitance change amount of C4-C8), that is, Δ C ═ Δ (C2-C6) + Δ (C4-C8).

When the touch sensor is subjected to a y-axis direction shearing force, the facing areas of the upper and lower electrode plates of the capacitors C1, C3, C5 and C7 are changed, so that the capacitance value is changed, and the facing areas of the upper and lower electrode plates of the capacitance values of the other 4 capacitors are unchanged, so that the capacitance value is unchanged.

Meanwhile, since C1 and C3 form a pair of interdigital capacitors and C5 and C7 form a pair of interdigital capacitors, C1 and C3 form a pair of differential signals, and C5 and C7 form a pair of differential signals. Therefore, the total capacitance value change amount of the tactile sensor under the action of the shear force in the y-axis direction is equal to (the capacitance change amount of C1-C3) + (the capacitance change amount of C5-C7), that is, Δ C ═ Δ (C1-C3) + Δ (C5-C7).

The bending moment in the x-axis direction can be regarded as two normal parallel forces with equal magnitude and opposite directions, C1, C2, C3, C4, C5, C6, C7 and C8 all change, the changing directions of C1, C3, C4 and C8 are the same, and the changing directions of C2, C6, C5 and C7 are the same. Therefore, the total capacitance value of the tactile sensor varies by (a capacitance variation of C1+ C3+ C4+ C8) - (a capacitance variation of C2+ C6+ C5+ C7), i.e., Δ C ═ Δ (C1+ C3+ C4+ C8) - Δ (C2+ C6+ C5+ C7).

The bending moment in the y-axis direction can be regarded as two normal parallel forces with equal magnitude and opposite directions, C1, C2, C3, C4, C5, C6, C7 and C8 all change, the changing directions of C1, C3, C2 and C6 are the same, and the changing directions of C5, C7, C4 and C8 are the same. Therefore, the total capacitance value of the tactile sensor varies by (a capacitance variation of C1+ C3+ C2+ C6) - (a capacitance variation of C5+ C7+ C4+ C8), i.e., Δ C ═ Δ (C1+ C3+ C2+ C6) - Δ (C5+ C7+ C4+ C8).

In this embodiment, the processor determines the stress type of the tactile sensor by determining whether the capacitance values of the capacitors in the tactile sensor change and the change direction thereof, calculates the corresponding capacitance value change amount according to the capacitance value change amount of each capacitor, the stress type and a calculation formula of the capacitance value change amount under the corresponding stress type, and obtains the value of the force and/or the moment according to the corresponding relationship between the capacitance value change amount and the force and/or the moment.

Example 3

Fig. 6 is a flowchart of a method for manufacturing a touch sensor according to the present invention. As shown in fig. 6, the method for manufacturing the tactile sensor according to the present invention is as follows:

step (a): an SMT steel mesh was prepared.

Step (b): and scraping an adhesive layer on the upper surface of the lower electrode by using a blade to form a first adhesive layer.

Step (c): a dielectric material is poured over the first adhesive layer.

Step (d): and uniformly coating a medium material on the first adhesive layer.

A step (e): and after the surface coated with the medium material is vacuumized, placing the SMT steel mesh and covering the PET film. Under the action of gravity, the medium material overflows from the pores of the SMT steel mesh and is laid between the SMT steel mesh and the PET film (as shown in (e) in FIG. 6).

Step (f): after turning over, the mixture is compacted for 12h by a weight.

Step (g): after the heavy object is taken down, turning over again, removing the PET film, taking down the SMT steel mesh, and forming a dielectric layer consisting of a plurality of dielectric blocks distributed in an array manner on the upper surface of the lower electrode; and scraping a bonding layer on the lower surface of the upper electrode by using a blade to serve as a second bonding layer, and positioning and integrating the upper printed circuit board and the lower printed circuit board together through pins.

A step (h): compacting with a weight for 12 h.

Step (i): and (5) taking down the weight to obtain the touch sensor.

Preferably, the time interval between step (b) and step (c) is less than 5 min.

Preferably, the dielectric material isSilicone RTV Silicone rubber.

Preferably, the binder is Sil-Poxy glue; the Sil-Poxy adhesive for bonding the dielectric layer and the upper and lower printed circuit boards is a special connecting agent for silica gel and other substrate materials, has strong viscosity, is easy to adhere to the surface of a substrate to form a compact film, can ensure the adhesion between the dielectric layer and the upper and lower printed circuit boards, and breaks through the problem of insufficient range of the touch sensor.

Compared with the prior art, the invention has the following advantages:

1) five-degree-of-freedom high-sensitivity detection: in order to respond to various external stimuli, the tactile sensor provided by the invention can simultaneously sense the positive pressure F_zShear force F_x、F_yAnd bending moment M_x、M_y. The upper and lower electrodes are made into an interdigital structure, and the dielectric layer is made into rectangular small squares distributed in an array manner, so that the filling rate of the dielectric layer is reduced, and high-sensitivity detection of positive pressure, shearing force and moment is realized.

2) The process is simple and miniaturized: according to the preparation method of the touch sensor, the dielectric layer is expanded in an array mode through the film pressing forming process, compared with the mode that the dielectric layer is manufactured firstly in the traditional process and then is transferred and integrated onto the electrode of the printed circuit board through the transfer film, the method adopts the SMT steel mesh to directly perform film pressing forming on the printed circuit board, eliminates damage to the dielectric layer in the transfer process and avoids introduction of bubbles, and has the advantages of being simple in process operation, low in cost and miniaturized in preparation.

3) High spatial resolution detection: the touch sensor provided by the invention expands the interdigital electrodes of the upper electrode and the lower electrode in an array manner, and realizes spatial force detection with high spatial resolution. As a small tactile sensor applied to a robot fingertip, sufficient spatially distributed force information can be provided for the robot.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to assist in understanding the core concepts of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.