Tactile sense and proximity sense sensor and detection method

Abstract

The invention discloses a tactile sense and proximity sense sensor and a detection method, and relates to the technical field of sensors, the sensor comprises a tactile sense and proximity sense sampling unit; the antenna comprises an upper substrate, a middle dielectric layer and a lower substrate from top to bottom in sequence. A bristle adhesion material is integrated on the surface of the lower substrate and is used for picking up a target object; the upper substrate comprises a first bottom interdigital electrode layer; the lower-layer substrate sequentially comprises a top-layer interdigitated electrode layer and a second bottom-layer interdigitated electrode layer from top to bottom; the first bottom-layer interdigitated electrode layer, the top-layer interdigitated electrode layer and the middle dielectric layer form a touch sensing layer; tactile information of the bristle adhesion material and the target object is determined according to the capacitance value of the tactile sensing layer; the second bottom interdigitated electrode layer is used as a proximity sense sensing layer, and the distance attitude information between the bristle adhesion material and the target object is determined by the capacitance values of the two proximity sense sensing layers in the same plane. According to the invention, the sensitivity of measuring tactile information and proximity information is improved.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to a tactile and proximity sensor and a detection method. Background Art

[0002] With the rapid development of the high-precision integrated circuit industry, the bionic dry adhesion picking technology based on van der Waals force has gradually attracted the attention of researchers. This technology can not only effectively grasp objects with smooth surfaces by imitating the wedge-shaped microstructure (bristles) on the soles of geckos, but also has excellent characteristics such as easy detachment, non-destructiveness, and no residue. However, in the picking and handling process, the relative posture difference between the surface of the bristle adhesion material and the surface of the picked object is crucial to the adhesion effect. The relative posture difference is mainly the angle between the planes where the two are located. Excessive relative posture difference will lead to the weakening of van der Waals force under the same pre-pressure, thereby affecting the adhesion effect. Therefore, how to obtain the relative posture difference information between the bristle adhesion material and the picked object is the key to determining whether effective grasping can be achieved.

[0003] Several common relative posture detection methods include: visual detection, laser sensor detection, inertial measurement unit (IMU) detection, ultrasonic sensor detection, etc. The posture measurement method based on visual detection is easily affected by object occlusion, background interference, etc.; the measurement method based on laser sensor has high requirements on the reflection characteristics of the object surface; IMU detects relative posture information through sensors such as accelerometers and gyroscopes, which may cause cumulative errors in long-term use; ultrasonic sensors cannot be used in vacuum and dust-free operating environments. Therefore, it is necessary to provide a new detection method that can simultaneously achieve tactile measurement and proximity measurement that are not affected by the environment and material properties and have advantages such as high sensitivity. Summary of the invention

[0004] The purpose of the present application is to provide a tactile and proximity sensor and detection method, which can simultaneously achieve high-sensitivity measurement of the distance posture information (i.e., proximity information) and tactile information between the bristle adhesion material and the target object.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] In a first aspect, the present application provides a tactile and proximity sensor, comprising: a tactile and proximity sampling unit; the tactile and proximity sampling unit comprises, from top to bottom, an upper substrate, an intermediate medium layer, and a lower substrate; a bristle adhesive material is integrated on the surface of the lower substrate, and the bristle adhesive material is used to pick up a target object;

[0007] The upper substrate comprises a first bottom interdigital electrode layer; the lower substrate comprises a top interdigital electrode layer and a second bottom interdigital electrode layer in order from top to bottom;

[0008] The first bottom interdigital electrode layer, the top interdigital electrode layer and the intermediate dielectric layer together constitute a tactile sensing layer; the first bottom interdigital electrode layer serves as an excitation electrode, and the top interdigital electrode layer serves as a receiving electrode; the capacitance value of the tactile sensing layer is used to determine the tactile information of the bristle adhesion material and the target object;

[0009] The second bottom interdigitated electrode layer serves as a proximity sensing layer, and the capacitance values ​​of the two proximity sensing layers in the same plane are used to determine the distance posture information between the bristle adhesion material and the target object, and the distance posture information serves as the proximity information between the bristle adhesion material and the target object.

[0010] Optionally, the first bottom interdigitated electrode layer includes four groups of tactile sensing excitation electrodes in a 2×2 array, and each group of the tactile sensing excitation electrodes is an interdigitated structure in which square wave excitation electrodes and active shielding electrodes are alternately distributed;

[0011] The top interdigitated electrode layer includes four groups of tactile sensing receiving electrodes in a 2×2 array, and each group of the tactile sensing receiving electrodes is an interdigitated structure in which signal detection receiving electrodes of two different channels are alternately distributed.

[0012] Optionally, the second bottom interdigitated electrode layer includes two groups of proximity sensing electrodes that are bilaterally symmetrical, and each group of proximity sensing electrodes is an interdigitated structure in which square wave excitation electrodes and one channel of signal detection receiving electrodes are alternately distributed.

[0013] Optionally, the intermediate medium layer is a sparse strip-shaped thin sheet structure arranged in parallel.

[0014] Optionally, the upper substrate also includes: a top-layer grounding copper shielding layer, an inner-layer active shielding copper layer, and an inner-layer routing and grounding copper shielding layer distributed from top to bottom; the inner-layer routing and grounding copper shielding layer is located above the first bottom-layer finger electrode layer.

[0015] Optionally, the lower substrate also includes: an inner layer of routing and grounding copper shielding layer and an inner second layer of grounding copper shielding layer distributed in sequence from top to bottom; the inner layer of routing and grounding copper shielding layer and the inner second layer of grounding copper shielding layer are located between the top layer of finger electrode layer and the second bottom layer of finger electrode layer; the inner layer of routing and grounding copper shielding layer and the inner second layer of grounding copper shielding layer are used to shield the interference of signals between the top layer of finger electrode layer and the second bottom layer of finger electrode layer.

[0016] Optionally, the tactile and proximity sensor further comprises: a capacitance-to-digital converter chip and a communication mainboard;

[0017] The capacitance-to-digital converter chip is connected to the lower substrate and the communication mainboard respectively; the capacitance-to-digital converter chip is used to collect the capacitance value of the touch sensing layer and the capacitance value of the proximity sensing layer, and send them to the communication mainboard;

[0018] The communication mainboard is used for:

[0019] Performing differential operation on the capacitance value of the tactile sensing layer to obtain tactile information of the bristle adhesion material and the target object; the capacitance value of the tactile sensing layer includes: eight tactile capacitance values; one tactile capacitance value is the capacitance value of a structure composed of a square wave excitation electrode in a group of tactile sensing excitation electrodes, a signal detection receiving electrode of a channel in a group of tactile sensing receiving electrodes, and an intermediate dielectric layer;

[0020] The angle and distance between the plane where the bristle adhesion material is located and the plane where the target object is located are calculated according to the capacitance value of the proximity sensing layer, and the angle and the distance are used as the distance posture information between the bristle adhesion material and the target object; the capacitance value of the proximity sensing layer includes: four proximity capacitance values; the capacitance value of each group of proximity sensing electrodes in the two second bottom-layer interdigitated finger electrode layers in the same plane is one of the proximity capacitance values.

[0021] Optionally, in calculating the angle and distance between the plane where the bristle adhesion material is located and the plane where the target object is located according to the capacitance value of the proximity sensing layer, and using the angle and the distance as the distance posture information between the bristle adhesion material and the target object, the communication mainboard is specifically used for:

[0022] The geometric centers of four groups of proximity sensing electrodes of two proximity sensing layers on the same plane are used as four detection positions;

[0023] Obtaining distances between four projection points of four detection positions projected on the target object according to the capacitance value of the proximity sensing layer;

[0024] Select any three projection points from the four projection points to determine four target planes;

[0025] The angle and distance between the plane where the bristle adhesion material is located and the plane where each target plane is located are calculated to obtain the distance posture information between the bristle adhesion material and the target object.

[0026] Optionally, the tactile and proximity sensor also includes: a host computer; the host computer is connected to the communication mainboard; the host computer is used to receive the distance posture information between the bristle adhesion material and the target object, and determine whether to adjust the posture of the tactile and proximity sensor according to the distance posture information.

[0027] In a second aspect, the present application provides a tactile and proximity detection method, which is used for any of the tactile and proximity sensors described above; comprising:

[0028] Obtaining a capacitance value of a touch sensing layer and a capacitance value of a proximity sensing layer;

[0029] determining tactile information of the bristle adhesion material and the target object according to the capacitance value of the tactile sensing layer;

[0030] The distance posture information between the bristle adhesion material and the target object is determined according to the capacitance values ​​of two proximity sensing layers located in the same plane; the distance posture information is used as the proximity information between the bristle adhesion material and the target object.

[0031] According to the specific embodiments provided in this application, this application has the following technical effects:

[0032] The present application provides a tactile and proximity sensor and a detection method. The first bottom finger electrode layer, the top finger electrode layer and the middle dielectric layer together constitute a tactile sensing layer to obtain tactile information; the second bottom finger electrode layer serves as a proximity sensing layer to obtain distance posture information. The present application can simultaneously perceive tactile information and posture detection functions through a capacitive-based tactile and proximity sensor. It is not limited by the properties of the material itself and environmental factors (such as light and temperature), has a fast response time, and can capture the relative posture difference between the bristle adhesion material and the target object in real time, thereby improving the measurement sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 A three-dimensional disassembled schematic diagram of a tactile and proximity sensor in one embodiment of the present application;

[0035] Figure 2 A schematic diagram of the distribution of square wave excitation electrodes and active shielding electrodes on the upper substrate provided in this application;

[0036] Figure 3 A schematic diagram of the distribution of different signal detection and receiving electrodes of the tactile sensing part of the lower substrate provided in this application;

[0037] Figure 4 A schematic diagram showing the distribution of two groups of signal detection and receiving electrodes and square wave excitation electrodes in the proximity sensing portion of the lower substrate provided in the present application;

[0038] Figure 5 A schematic diagram showing the principle of measuring tactile information by causing a change in capacitance when the tactile and proximity sensors provided by the present application are subjected to normal pressure, shear force, and torque;

[0039] Figure 6 A schematic diagram of the principle of detecting the difference in posture between the plane where the sensor is located and the target surface through the proximity sensing function provided in this application;

[0040] Figure 7 A schematic diagram of the power conversion module circuit provided for this application;

[0041] Figure 8 Schematic diagram of the CAN bus communication module circuit provided for this application;

[0042] Fig. 9 A schematic diagram of the power input protection module circuit provided for this application;

[0043] Fig.10 Schematic diagram of the IIC communication protection module circuit provided for this application;

[0044] Fig.11 Schematic diagram of the circuit principle of the MCU core processing module provided for this application;

[0045] Fig.12 This is a schematic diagram of the circuit principle of the capacitance signal acquisition module provided in this application.

[0046] Figure numerals: 1 - internal copper plating and routing area of ​​the upper substrate, 2 - first bottom finger electrode layer, 3 - intermediate dielectric layer, 4 - top finger electrode layer, 5 - internal copper plating and routing area of ​​the lower substrate, 6 - second bottom finger electrode layer. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0048] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0049] In an exemplary embodiment, Figure 1 As shown, a tactile and proximity sensor is provided, which includes a tactile and proximity sampling unit; the tactile and proximity sampling unit includes, from top to bottom, an upper substrate, an intermediate medium layer 3 and a lower substrate; bristle adhesive material is integrated on the surface of the lower substrate, and the bristle adhesive material is used to pick up the target object.

[0050] The upper substrate includes a first bottom interdigital electrode layer 2 ; the lower substrate includes a top interdigital electrode layer 4 and a second bottom interdigital electrode layer 6 in order from top to bottom.

[0051] The first bottom interdigital electrode layer 2, the top interdigital electrode layer 4 and the middle dielectric layer 3 together constitute a tactile sensing layer; the first bottom interdigital electrode layer 2 serves as an excitation electrode, and the top interdigital electrode layer 4 serves as a receiving electrode; the capacitance value of the tactile sensing layer is used to determine the tactile information of the bristle adhesion material and the target object.

[0052] The first bottom interdigitated electrode layer 2 includes four groups of tactile sensing excitation electrodes in a 2×2 array, each group of tactile sensing excitation electrodes is an interdigitated structure consisting of square wave excitation electrodes and active shielding electrodes alternately distributed. The main function of the square wave excitation electrode is to couple with the signal detection receiving electrode of the tactile sensing receiving electrode to generate an electric field to achieve differential measurement of capacitance. Figure 2 As shown, there are four groups of interdigitated electrode regions formed by alternating square wave excitation electrodes and active shielding electrodes.

[0053] Corresponding to the first bottom interdigital electrode layer 2 of the upper substrate, the top interdigital electrode layer 4 includes four groups of tactile sensing receiving electrodes in a 2×2 array, and each group of tactile sensing receiving electrodes is an interdigital structure in which signal detection receiving electrodes of two different channels are alternately distributed. Figure 3 As shown, signal detection receiving electrodes of different channels are arranged alternately to form four groups of interdigitated electrode areas corresponding to the upper substrate electrodes.

[0054] The contact force / torque is transmitted to the intermediate dielectric layer 3 through the upper substrate, and the deformation of the intermediate dielectric layer 3 causes the inter-electrode capacitance to change, thereby realizing the tactile detection function.

[0055] The second bottom interdigitated electrode layer 6 is used as a proximity sensing layer. The capacitance values ​​of the two proximity sensing layers in the same plane are used to determine the distance posture information between the bristle adhesion material and the target object. The distance posture information is used as the proximity information between the bristle adhesion material and the target object. The relative posture measurement function based on proximity requires the use of two sensors in combination. The two sensors themselves are in the same plane. By determining the distance information of four points on the plane where the target object is located, the plane information where the target object is located is obtained. By comparing the angle between the normal vector of the plane where the bristle adhesion material (i.e., the tactile and proximity sensor) is located and the normal vector of the plane where the target object is located, the posture difference information of the two planes is calculated, thereby realizing the relative posture measurement function.

[0056] The second bottom interdigital electrode layer 6 includes two groups of proximity sensing electrodes that are bilaterally symmetrical, and each group of proximity sensing electrodes is an interdigital structure in which square wave excitation electrodes and one channel of signal detection receiving electrodes are alternately distributed. Figure 4 As shown, the signal detection receiving electrodes and the square wave excitation electrodes are alternately arranged to form two groups of interdigitated proximity sensing electrode areas.

[0057] When the tactile and proximity sensors approach the target object, the target object will affect the coupling electric field distribution between the square wave excitation electrode and the signal detection receiving electrode. The greater the capacitance change caused by this influence as the target object approaches, the proximity sensing electrode is used to detect the distance between the group of electrode areas and the target object, and directly read the capacitance values ​​of C9 and C10, thereby realizing the proximity detection function. C9 and C10 are the capacitance values ​​of a group of proximity sensing electrodes in the second bottom interdigitated electrode layer 6.

[0058] The intermediate dielectric layer 3 is a sparse strip-shaped thin sheet structure arranged in parallel. The material of the intermediate dielectric layer 3 is silica gel. In this easily deformable sparse structure, the dielectric layer filling rate is adjusted by designing the width and number of the strips, thereby adjusting the sensitivity of the tactile and proximity sensors.

[0059] like Figure 1 As shown, the upper substrate is a four-layer PCB (Printed Circuit Board) board, and the upper substrate also includes: an internal copper plating and routing area 1 of the upper substrate; the internal copper plating and routing area 1 of the upper substrate is distributed from top to bottom in sequence: a top-layer grounding copper plating shielding layer, an inner-layer active shielding copper plating layer, and an inner-layer routing and grounding copper plating shielding layer; the inner-layer routing and grounding copper plating shielding layer is located above the first bottom-layer interdigitated electrode layer 2.

[0060] The lower substrate is a four-layer PCB board, and the lower substrate also includes: an internal copper plating and routing area 5 of the lower substrate; the internal copper plating and routing area 5 of the lower substrate is distributed with an inner first layer of routing and grounding copper plating shielding layer and an inner second layer of grounding copper plating shielding layer from top to bottom; the inner first layer of routing and grounding copper plating shielding layer and the inner second layer of grounding copper plating shielding layer are located between the top layer of finger electrode layer 4 and the second bottom layer of finger electrode layer 6; the inner first layer of routing and grounding copper plating shielding layer and the inner second layer of grounding copper plating shielding layer are used to shield the interference of signals between the top layer of finger electrode layer 4 and the second bottom layer of finger electrode layer 6.

[0061] The touch and proximity sensor also includes: a capacitance digital converter (CDC) chip, peripheral circuit components and a communication mainboard.

[0062] The capacitance-to-digital converter chip is connected to the lower substrate and the communication mainboard respectively; the CDC chip and peripheral circuit components are welded on the lower substrate. The peripheral circuit components include components such as capacitors and resistors, which are responsible for the collection and conversion of capacitance analog signals and upload them to the communication mainboard; this embodiment uses a programmable CDC conversion chip, and the active shielding of the chip is used to isolate the wiring of each detection channel drawn from the chip, thereby reducing the generation of coupling capacitance between internal lines; each layer of the upper substrate and the lower substrate is connected to an active shielding or grounding copper area, thereby reducing the influence of parasitic capacitance and external stray capacitance.

[0063] The capacitance-to-digital converter chip is used to collect the capacitance value of the touch sensing layer and the capacitance value of the proximity sensing layer, and send them to the communication mainboard.

[0064] The communication motherboard is used for:

[0065] A differential operation is performed on the capacitance value of the tactile sensing layer to obtain tactile information of the bristle adhesion material and the target object; the capacitance value of the tactile sensing layer includes: eight tactile capacitance values; one tactile capacitance value is the capacitance value of a structure composed of a square wave excitation electrode in a group of tactile sensing excitation electrodes, a signal detection receiving electrode of a channel in a group of tactile sensing receiving electrodes, and an intermediate dielectric layer 3.

[0066] The angle and distance between the plane where the bristle adhesion material is located and the plane where the target object is located are calculated according to the capacitance value of the proximity sensing layer, and the angle and distance are used as the distance posture information between the bristle adhesion material and the target object; the capacitance value of the proximity sensing layer includes: four proximity sensing capacitance values; the capacitance value of each group of proximity sensing electrodes in the two second bottom-layer interdigitated finger electrode layers 6 that are in the same plane is a proximity sensing capacitance value.

[0067] The communication mainboard includes core components such as MCU (microcontroller unit), CAN (controller area network), LDO (low dropout regulator) and their peripheral circuits, which are responsible for powering the touch and proximity sampling units and uploading the collected data to the host computer in real time. The data collected by the CDC chip is transmitted to the MCU through IIC communication.

[0068] For the specific configuration and working principle of the force / torque measurement device based on the tactile sensing part, please refer to the following embodiments.

[0069] In another exemplary embodiment of the present application, in performing differential operation on the capacitance value of the tactile sensing layer to obtain tactile information of the bristle adhesion material and the target object, the communication mainboard is specifically used for:

[0070] The capacitance value read by the touch sensing layer (i.e., the force / torque sensing electrode) is differentially calculated, such as Figure 3 As shown, assuming that the capacitance value measured by channel n is Cn, when the sensor is subjected to tangential force, the tangential X and Y axis forces are: Fx=C1+C5-C2-C6; Fy=C3+C7-C4-C8, when the sensor is subjected to normal force, the normal Z axis force is: Fz=C1+C2+C3+C4+C5+C6+C7+C8; when the sensor is subjected to torque, the two-axis torques in the X and Y directions are: Mx=C1+C2+C7+C8-C3-C4-C5-C6; My=C5+C6+C7+C8-C1-C2-C3-C4, the original capacitance value of each channel is calculated according to the above formula, so as to obtain five-axis force / torque information; the five-axis force / torque information is used as tactile information.

[0071] like Figure 1 As shown, the tactile sensing part of the sensor is mainly composed of 1 and 2 in the upper substrate, the middle dielectric layer 3, and 4 and 5 in the lower substrate, which are stacked layer by layer. 2 and 4 are used as excitation and receiving electrodes, which couple to generate an electric field. The capacitance changes with the change of the facing area or vertical distance between the excitation and receiving electrodes. The change of the facing area or vertical distance is achieved through the force deformation of the middle dielectric layer 3. In practical applications, the upper substrate is fixed. When the lower substrate of the sensor is subjected to external force, the middle dielectric layer 3 will produce corresponding deformation, causing the lower substrate to produce relative movements such as pitch and yaw, thereby causing changes in the facing area or vertical distance between the excitation and receiving electrodes. The CDC chip receives and converts the signal to detect the capacitance change measured by the receiving electrode, thereby obtaining the relationship between the capacitance change ΔC and the force / torque, and then outputs the positive pressure Fz, shear force Fx / Fy and torque Mx / My. The working principle diagram is shown in Figure 5 shown.

[0072] like Figure 5 Part (a) shows the situation where the tactile and proximity sensors are not subjected to any force / torque, and d is the thickness of the intermediate dielectric layer.

[0073] like Figure 5 As shown in part (b) of FIG. 1 , when the touch and proximity sensors are subjected to a normal positive pressure Fz, the intermediate dielectric layer 3 undergoes a vertical compression deformation, and the thickness of the dielectric layer is reduced by Δd from the original d. Since the vertical distance between the upper and lower electrodes changes, the sum of the capacitance changes caused by the normal positive pressure Fz is: ΔC Fz =Δ(C1+C2+C3+C4+C5+C6+C7+C8); where ΔC Fz It is the sum of the capacitance changes caused by the normal positive pressure Fz of the tactile and proximity sensors, such as Figure 3 As shown, C1, C2, C3, C4, C5, C6, C7 and C8 are the capacitance values ​​of the structure formed by the square wave excitation electrode in the tactile sensing excitation electrode and channel 1, channel 2, channel 3, channel 4, channel 5, channel 6, channel 7 and channel 8 and the intermediate dielectric layer respectively.

[0074] When the tactile and proximity sensors are subjected to tangential force (i.e. shear force) Fx or Fy, Figure 5 As shown in part (c) of the diagram, when the sensor is subjected to a tangential force Fx or Fy, the lower substrate will produce a tangential displacement ΔL relative to the upper substrate, causing the facing area of ​​the excitation electrode and the signal receiving electrode to change. At this time, the sum of the capacitance changes caused by the force in the x-axis direction is: ΔC Fx =Δ(C1+C5-C2-C6), ΔC Fx is the sum of the capacitance changes of the touch and proximity sensors caused by the force in the x-axis direction. When the sensor is subjected to the force in the y-axis direction, ΔC Fy =Δ(C3+C7-C4-C8), ΔC Fy It is the sum of the capacitance changes of the touch and proximity sensors caused by the force in the y-axis direction.

[0075] like Figure 5 As shown in part (d) of the figure, when the tactile and proximity sensors are subjected to torque Mx or My, one side of the intermediate dielectric layer 3 is stretched and the thickness becomes d+Δd1; one side is compressed and the thickness becomes d-Δd2. When the sensor is subjected to x-axis torque ΔC Mx =Δ(C1+C2+C7+C8-C3-C4-C5-C6),ΔC Mx is the sum of the capacitance changes of the touch and proximity sensors when subjected to the x-axis torque. When the sensor is subjected to the y-axis torque, ΔC My=Δ(C5+C6+C7+C8-C1-C2-C3-C4),ΔC My It is the sum of the capacitance changes of the touch and proximity sensors due to the y-axis torque.

[0076] For the relative posture difference measurement method based on the proximity sensing part, please refer to the following embodiment.

[0077] In another exemplary embodiment of the present application, in calculating the angle and distance between the plane where the bristle adhesion material is located and the plane where the target object is located according to the capacitance value of the proximity sensing layer, and using the angle and distance as the distance posture information between the bristle adhesion material and the target object, the communication mainboard specifically performs the following operations:

[0078] like Figure 6 As shown, the geometric centers of four groups of proximity sensing electrodes of two proximity sensing layers located in the same plane are used as four detection positions.

[0079] Specifically, the center point of the two tactile and proximity sensors in the same plane is taken as the origin, the directions parallel to the length and width of the tactile and proximity sensors are the x-axis and the y-axis respectively, the direction perpendicular to the plane where the tactile and proximity sensors are located is the z-axis, A1, A2, A3, and A4 are respectively the geometric centers of each group of proximity sensing electrodes of the two tactile and proximity sensors in the same plane, A1, A2, A3, and A4 are respectively the detection positions where the foot end of the target object approaches the tactile and proximity sensors, and the coordinates of the plane α where the four points are located are expressed as:

[0080]

[0081] α:z=0.

[0082] Wherein, a and b are the length and width of the rectangle formed by the detection position points of the foot end proximity sensor of the target object.

[0083] The distances between four projection points of the four detection positions projected on the target object are obtained according to the capacitance value of the proximity sensing layer.

[0084] Specifically, B1, B2, B3, and B4 are the i The corresponding projection points, the coordinates of the four points relative to the surface of the tactile and proximity sensors can be expressed as:

[0085]

[0086] Among them, l i (i=1,2,3,4) is the vertical distance between the i-th detection position and the surface of the target object.

[0087] Select any three projection points from the four projection points to determine the four target planes.

[0088] Specifically, the target planes formed by taking any three projection points in B1, B2, B3, and B4 are β1, β2, β3, and β4 respectively, and the equation can be expressed as:

[0089] β i :M i x+N i y+P i z+Q i =0(i=1,2,3,4).

[0090] Among them, M i 、N i , P i and Q i The target plane β i The coefficient of .

[0091] The angle and distance between the plane where the bristle adhesion material is located and the plane where each target plane is located are calculated to obtain the distance posture information between the bristle adhesion material and the target object.

[0092] Specifically, determine the normal vector of the plane α where the bristle adhesion material is located and each target plane β i Normal vector of plane α and plane β i The normal vector λ A and λ Bi They are:

[0093] λ A =

[001] T .

[0094] λ Bi =[M i N i P i ] T .

[0095] Where α is the plane where the bristle adheres to the material, β i is the target plane; A is the normal vector of the plane where the bristle adheres to the material, λ Bi is the normal vector of the target plane.

[0096] Among them, the angle between the normal vectors of the two planes is determined according to the normal vector of the plane where the bristle adhesion material is located and the normal vector of each target plane:

[0097]

[0098] Through trigonometric functions, we can get:

[0099]

[0100] The coordinate origin O(0,0,0) of the plane where the bristle adhesion material is located to the target plane β i The distance can be calculated as:

[0101]

[0102] The tactile and proximity sensor also includes: a host computer; the host computer is connected to the communication mainboard; the host computer is used to receive the distance posture information between the bristle adhesion material and the target object, and determine whether to adjust the posture of the tactile and proximity sensor according to the distance posture information.

[0103] Specifically, in order to more accurately represent the relative posture of the sensor plane and the target plane, the target plane β i The normal vector λ in Bi The angle θ i and the distance d i Tolerance judgment:

[0104]

[0105] Among them, θ max =max{θ1,θ2,θ3,θ4},θ min =min{θ1,θ2,θ3,θ4},d max =max{d1,d2,d3,d4}, d min =min{d1,d2,d3,d4},K θ is the safety factor of the angle, K d is the safety factor of the distance, if the angle θ i and the distance d i If it is not within the tolerance range, it means that the surface of the target object at the current approach position may be raised or suspended, and feedback needs to be given to the host computer to adjust the approach position.

[0106] If the angle θ i and the distance d i If all are within the tolerance range, the mean of the four sets of angle and distance parameters can be taken as the output values ​​θ and d and uploaded to the host computer to determine whether attitude adjustment is needed and how to adjust the attitude. The calculation formula for the mean of the four sets of angle and distance parameters is:

[0107]

[0108] Among them, θ is the mean of the four groups of angles, and d is the mean of the four groups of distance parameters.

[0109] Furthermore, the force / torque information of each axis is calibrated by using standard weights and a calibration platform; the tactile and proximity sensors are pushed toward the target object by a stepper motor with a fixed step length, and the proximity distance information is calibrated, thereby intuitively reflecting the tactile and proximity information.

[0110] The circuit of the touch and proximity sensor includes the communication mainboard schematic diagram and the sensor unit schematic diagram; Figure 7-Figure 11 As shown in the figure, the schematic diagram of the communication mainboard includes: the circuit diagram of the power conversion module, the CAN bus communication module, the power input protection module, the IIC communication protection module and the MCU core processing module. The power conversion module is divided into two parts, one part converts the 24V power supply to 5V, and the other part converts 5V to 3.3V. The circuit structure and connection relationship of each part of the power conversion module are shown in the figure. Figure 7 As shown; the CAN bus communication module includes sending and receiving pins, and the circuit structure and connection relationship are as shown Figure 8 As shown; the power input protection module uses components such as inductors, capacitors and Schottky diodes to achieve the power input protection function. The circuit structure and connection relationship are shown in Fig. 9 As shown; the IIC communication protection module uses components such as resistors and voltage regulator diodes. The circuit structure and connection relationship are as follows Fig.10 As shown; the MCU core processing module is connected to the pins of the IIC communication protection module, and the circuit structure and connection relationship are as shown Fig.11 The sensor unit schematic diagram includes: a circuit diagram of a capacitance signal acquisition module; the capacitance signal acquisition module includes capacitance signal pins, circuit structure and connection relationship as shown in FIG. Fig.12 shown.

[0111] In response to current research problems and needs, the present application proposes a highly sensitive tactile and proximity sensor based on the capacitance principle, which directly integrates bristle adhesion material into the surface of the tactile and proximity sensor. By designing the distribution of tactile and proximity capacitance electrodes, multi-degree-of-freedom force, torque detection and proximity detection functions can be realized, and a detection method for the relative posture difference with the surface of the target object during the process of approaching the target object and after critical contact is provided. The relative posture difference of the bristle adhesion material during the process of approaching the target object and the relative posture difference between the two after critical contact are reflected by multiple proximity distance measurement points and tactile sensing signals, thereby measuring the distance posture information and tactile information of the bristle adhesion material and the target object.

[0112] The capacitive sensor of the present application can realize tactile measurement and proximity measurement at the same time. It has the advantages of high sensitivity, fast response, low power consumption, etc., and also has the characteristics of small size and high integration. It is easy to be integrated with the bristle adhesion material, and is expected to become an effective way to obtain the relative posture difference information between the bristle adhesion material and the picked up object.

[0113] Based on the same inventive concept, the embodiment of the present application further provides a tactile and proximity detection method for implementing the tactile and proximity sensors involved above. The tactile and proximity detection method is used for the tactile and proximity sensors in the above embodiments; the tactile and proximity detection method includes:

[0114] The capacitance value of the touch sensing layer and the capacitance value of the proximity sensing layer are obtained.

[0115] The tactile information of the bristle adhesion material and the target object is determined according to the capacitance value of the tactile sensing layer.

[0116] The distance and posture information between the bristle adhesion material and the target object is determined according to the capacitance values ​​of two proximity sensing layers located in the same plane; the distance and posture information is used as the proximity information between the bristle adhesion material and the target object.

[0117] The present application discloses a five-degree-of-freedom tactile and proximity sensor with posture sensing function, and its overall structure is divided into three parts: an upper substrate, an intermediate dielectric layer, and a lower substrate, which can be used to detect normal force, tangential force, and torque, and can also be used to detect the proximity distance and relative posture of a target object. Based on the manufacturing technology of a multi-layer printed circuit board, the present application arranges grounding and active shielding copper areas on the inner layer of the circuit board and the periphery of the electrode, thereby reducing the influence of parasitic capacitance and external stray capacitance on signal detection; the electrode distribution on each layer of the substrate is designed to be an array-type alternating finger-shaped structure, and the filling rate of the intermediate dielectric layer is designed and adjusted, thereby achieving high-sensitivity tactile and proximity sensing functions, and at the same time introduces a method for solving the relative posture difference of the plane based on the proximity sensing function.

[0118] Compared with the prior art, this application has the following advantages:

[0119] (1) Five-axis force / torque detection: This application can simultaneously sense five-axis contact force / torque, including normal tension and pressure (i.e. normal force), shear force (and tangential force), torque (i.e. torque) and other tactile information.

[0120] (2) Highly integrated: The communication and data processing circuits of the present application are independent of another main board, which further simplifies the structure of the tactile and proximity sampling unit. The tactile and proximity sampling unit consists of only two layers of PCB boards and a sub-millimeter-thick dielectric layer, with a size of only 20×30×2.4mm, which facilitates the direct integration of bristle adhesion materials on the sensor, thereby improving the fine manipulation capability of the bionic stem adhesion actuator, and is suitable for application scenarios with limited space.

[0121] (3) High-sensitivity detection: The tactile sensing part of the sensor of this application adopts a differential capacitor circuit design to achieve extremely high resolution. At the same time, by designing a sparse strip filling structure of the intermediate dielectric layer, the sensitivity of the sensor to tangential force, normal force and torque is significantly improved.

[0122] (4) Non-contact posture detection function: This application proposes for the first time a posture detection function based on a capacitive proximity sensor, which accurately calculates the relative posture difference between the bristle adhesion material and the target object through highly sensitive detection of the distance to the target object. It is not limited by the properties of the material itself and environmental factors (such as light and temperature), has a fast response time, and can capture the relative posture difference between the bristle adhesion material and the target object in real time. This enables the control terminal to quickly adjust the posture of the adhesion end according to the data uploaded by the sensor in a dynamic environment, ensuring the reliability of grasping and handling.

[0123] (5) Strong anti-interference capability: This application significantly enhances the anti-interference capability of the sensor by using the square wave excitation source and active shielding signal of the CDC chip, reduces the influence of parasitic capacitance and environmental stray capacitance caused by integrated miniaturization, and improves the stability of signal output.

[0124] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0125] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A tactile and proximity sensor, characterized in that: The touch and proximity sensor comprises a touch and proximity sampling unit; The tactile and proximity sampling unit includes, from top to bottom, an upper substrate, an intermediate medium layer and a lower substrate; A bristle adhesive material is integrated on the surface of the lower substrate, and the bristle adhesive material is used to pick up the target object; The upper substrate comprises a first bottom interdigital electrode layer; the lower substrate comprises a top interdigital electrode layer and a second bottom interdigital electrode layer in order from top to bottom; The first bottom interdigital electrode layer, the top interdigital electrode layer and the intermediate dielectric layer together constitute a tactile sensing layer; the first bottom interdigital electrode layer serves as an excitation electrode, and the top interdigital electrode layer serves as a receiving electrode; the capacitance value of the tactile sensing layer is used to determine the tactile information of the bristle adhesion material and the target object; The second bottom interdigitated electrode layer serves as a proximity sensing layer, and the capacitance values ​​of the two proximity sensing layers in the same plane are used to determine the distance posture information between the bristle adhesion material and the target object, and the distance posture information serves as the proximity information between the bristle adhesion material and the target object.

2. The tactile and proximity sensor according to claim 1, characterized in that: The first bottom interdigitated electrode layer includes four groups of tactile sensing excitation electrodes in a 2×2 array, and each group of the tactile sensing excitation electrodes is an interdigitated structure in which square wave excitation electrodes and active shielding electrodes are alternately distributed; The top interdigitated electrode layer includes four groups of tactile sensing receiving electrodes in a 2×2 array, and each group of the tactile sensing receiving electrodes is an interdigitated structure in which signal detection receiving electrodes of two different channels are alternately distributed.

3. The tactile and proximity sensor according to claim 2, characterized in that: The second bottom interdigitated electrode layer includes two groups of proximity sensing electrodes that are bilaterally symmetrical, and each group of proximity sensing electrodes is an interdigitated structure in which square wave excitation electrodes and one channel of signal detection receiving electrodes are alternately distributed.

4. The tactile and proximity sensor according to claim 1, characterized in that: The intermediate medium layer is a sparse strip-shaped thin sheet structure arranged in parallel.

5. The tactile and proximity sensor according to claim 1, characterized in that: The upper substrate also includes: a top grounding copper shielding layer, an inner active shielding copper layer, and an inner second wiring and grounding copper shielding layer, which are distributed from top to bottom; the inner second wiring and grounding copper shielding layer is located above the first bottom finger electrode layer.

6. The touch and proximity sensor according to claim 1, characterized in that: The lower substrate also includes: an inner layer of routing and grounding copper shielding layer and an inner second layer of grounding copper shielding layer distributed in sequence from top to bottom; the inner layer of routing and grounding copper shielding layer and the inner second layer of grounding copper shielding layer are located between the top layer of finger electrode layer and the second bottom layer of finger electrode layer; the inner layer of routing and grounding copper shielding layer and the inner second layer of grounding copper shielding layer are used to shield the interference of signals between the top layer of finger electrode layer and the second bottom layer of finger electrode layer.

7. The touch and proximity sensor according to claim 3, characterized in that: The touch and proximity sensor also includes: a capacitance digital converter chip and a communication mainboard; The capacitance-to-digital converter chip is connected to the lower substrate and the communication mainboard respectively; the capacitance-to-digital converter chip is used to collect the capacitance value of the touch sensing layer and the capacitance value of the proximity sensing layer, and send them to the communication mainboard; The communication mainboard is used for: Performing differential operation on the capacitance value of the tactile sensing layer to obtain tactile information of the bristle adhesion material and the target object; the capacitance value of the tactile sensing layer includes: eight tactile capacitance values; one tactile capacitance value is the capacitance value of a structure composed of a square wave excitation electrode in a group of tactile sensing excitation electrodes, a signal detection receiving electrode of a channel in a group of tactile sensing receiving electrodes, and an intermediate dielectric layer; The angle and distance between the plane where the bristle adhesion material is located and the plane where the target object is located are calculated according to the capacitance value of the proximity sensing layer, and the angle and the distance are used as the distance posture information between the bristle adhesion material and the target object; the capacitance value of the proximity sensing layer includes: four proximity capacitance values; the capacitance value of each group of proximity sensing electrodes in the two second bottom-layer interdigitated finger electrode layers in the same plane is one of the proximity capacitance values.

8. The tactile and proximity sensor according to claim 7, characterized in that: In terms of calculating the angle and distance between the plane where the bristle adhesion material is located and the plane where the target object is located according to the capacitance value of the proximity sensing layer, and using the angle and the distance as the distance posture information between the bristle adhesion material and the target object, the communication mainboard is specifically used for: The geometric centers of four groups of proximity sensing electrodes of two proximity sensing layers on the same plane are used as four detection positions; Obtaining distances between four projection points of four detection positions projected on the target object according to the capacitance value of the proximity sensing layer; Select any three projection points from the four projection points to determine four target planes; The angle and distance between the plane where the bristle adhesion material is located and the plane where each target plane is located are calculated to obtain the distance posture information between the bristle adhesion material and the target object.

9. The tactile and proximity sensor according to claim 7, characterized in that: The tactile and proximity sensor also includes: a host computer; the host computer is connected to the communication mainboard; the host computer is used to receive the distance posture information between the bristle adhesion material and the target object, and determine whether to adjust the posture of the tactile and proximity sensor according to the distance posture information.

10. A method for detecting touch and proximity, characterized in that: The tactile and proximity detection method is used for the tactile and proximity sensor according to any one of claims 1 to 9; The touch and proximity detection method comprises: Obtaining a capacitance value of a touch sensing layer and a capacitance value of a proximity sensing layer; determining tactile information of the bristle adhesion material and the target object according to the capacitance value of the tactile sensing layer; The distance posture information between the bristle adhesion material and the target object is determined according to the capacitance values ​​of two proximity sensing layers located in the same plane; the distance posture information is used as the proximity information between the bristle adhesion material and the target object.

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