Flexible array sensor, sensing system and sensing shoe

Abstract

The application discloses a flexible array sensor, a sensing system and a sensing shoe. The sensor comprises a plurality of sensing units arranged in an array. The sensing units comprise, from top to bottom, a loading block, a first electrode plate, a dielectric layer, a second electrode plate and a substrate. The loading block is tightly attached to the first electrode plate. The first electrode plate and the second electrode plate are parallel to each other. The first electrode plate comprises a plurality of first working electrodes arranged in an array in a symmetrical manner. The first working electrodes in a first direction are connected in series. The second electrode plate comprises a plurality of second working electrodes arranged in an array in a symmetrical manner. The second working electrodes in a second direction are connected in series. The first direction is orthogonal to the second direction. The center positions of the first working electrodes and the corresponding second working electrodes coincide. The dielectric layer is used to separate the first electrode plate and the second electrode plate. The substrate is tightly attached to the second electrode plate. The flexible array sensor has the characteristics of high measurement accuracy and high spatial resolution.

Description

Technical Field

[0001] This application relates to the field of sensor technology, and in particular to a flexible array sensor, a sensing system, and a sensing shoe. Background Technology

[0002] In the human lower limbs, the foot is the only part that comes into contact with the ground. Its influence on postural control is significant, and changes in gait can be represented by variations in the reaction force of the foot against the ground.

[0003] In fields such as gait analysis, sports biomechanics, and rehabilitation engineering, wearable plantar pressure measurement systems face three major technical limitations: flexible sensor arrays cannot calculate multidimensional forces on the sole and have poor accuracy under curved surface loads; commercially available rigid multidimensional force sensing shoe systems affect normal gait and cannot meet the requirements for high spatial resolution plantar pressure detection; and in wearable modular plantar force measurement systems, the cumulative error of inertial sensors restricts the reliability of long-term dynamic measurements. Summary of the Invention

[0004] The main technical problem addressed by this application is to provide a flexible array sensor, sensing system, and sensing shoe, which solves the problems of poor accuracy under curved surface loads in existing wearable plantar pressure measurement systems, difficulty in meeting the requirements for high spatial resolution pressure detection of the plantar surface, and the limitation of long-term dynamic measurement due to error accumulation.

[0005] To address the aforementioned technical problems, this application provides a flexible array sensor comprising multiple sensing units arranged in an array. Each sensing unit, from top to bottom, includes a loading block, a first electrode plate, a dielectric layer, a second electrode plate, and a substrate. The loading block is tightly fitted to the first electrode plate, transmitting external force to the first electrode plate and causing deformation of the dielectric layer. The first and second electrode plates are parallel to each other. The first electrode plate includes multiple first working electrodes arranged in an array symmetrically, with each first working electrode in a first direction connected in series. The second electrode plate includes multiple second working electrodes arranged in an array symmetrically, with each second working electrode in a second direction connected in series, and the first and second directions are orthogonal. The center positions of each first working electrode and its corresponding second working electrode coincide. The dielectric layer separates the first and second electrode plates. The substrate is tightly fitted to the second electrode plate.

[0006] This application also provides a sensing system, which includes two flexible array sensors as described above, and the two flexible array sensors are fixedly connected through a plurality of corresponding substrates for simultaneously sensing multidimensional forces on both sides.

[0007] This application also provides a sensing shoe, including an upper and a sole composed of the sensing system described above, wherein one of the flexible array sensors is used to contact the sole of the foot to detect multi-dimensional pressure in the sole zones; and the other flexible array sensor is used to contact the ground to detect overall three-dimensional ground reaction force.

[0008] The beneficial effects of this application are as follows: This application discloses a flexible array sensor, a sensing system, and a sensing shoe. The flexible array sensor includes multiple sensing units distributed in an array. Each sensing unit includes, from top to bottom, a loading block, a first electrode plate, a dielectric layer, a second electrode plate, and a substrate. The loading block is tightly attached to the first electrode plate to transfer external force to the first electrode plate, causing deformation of the dielectric layer. The first and second electrode plates are parallel to each other. The first electrode plate includes multiple first working electrodes symmetrically distributed in an array, with each first working electrode in a first direction connected in series. The second electrode plate includes multiple second working electrodes symmetrically distributed in an array, with each second working electrode in a second direction connected in series. The first and second directions are orthogonal, and the center positions of each first working electrode and its corresponding second working electrode coincide. The dielectric layer is used to separate the first and second electrode plates. The substrate is tightly attached to the second electrode plate. This flexible array sensor features high pressure measurement accuracy and high spatial resolution. Furthermore, the sensing system and sensing shoe composed of this flexible array sensor can simultaneously collect multidimensional forces between the foot and shoe / shoe and the ground, and calculate the pressure in each zone of the sole. Attached Figure Description

[0009] Figure 1 This is a structural diagram of an embodiment of a flexible array sensor according to this application;

[0010] Figure 2 This is a schematic diagram showing the distribution of sensing units in one embodiment of a flexible array sensor according to this application;

[0011] Figure 3 This is a cross-sectional schematic diagram of a sensing unit in one embodiment of a flexible array sensor according to this application;

[0012] Figure 4 This is a schematic diagram of the circuit principle within the sensing unit of a flexible array sensor according to an embodiment of this application;

[0013] Figure 5 This is a schematic diagram of the array electrode arrangement in one embodiment of a flexible array sensor according to this application;

[0014] Figure 6 This is a schematic diagram of the array electrode structure in one embodiment of a flexible array sensor according to this application;

[0015] Figure 7This is a schematic diagram of the composition of a sensing model in one embodiment of a flexible array sensor according to this application;

[0016] Figure 8 This is a force analysis diagram of a sensing model in one embodiment of a flexible array sensor according to this application;

[0017] Figure 9 This is a force analysis diagram of the sensing unit in one embodiment of a flexible array sensor according to this application;

[0018] Figure 10 This is a schematic diagram of the composition of the initial array sensing model in one embodiment of a flexible array sensor according to this application;

[0019] Figure 11 This is a force analysis diagram of the initial array sensing model in one embodiment of a flexible array sensor according to this application;

[0020] Figure 12 This is another force analysis diagram of the initial array sensing model in one embodiment of a flexible array sensor of this application;

[0021] Figure 13 This is another force analysis diagram of the initial array sensing model in one embodiment of a flexible array sensor of this application;

[0022] Figure 14 This is a schematic diagram of the composition of a target array sensing model in one embodiment of a flexible array sensor according to this application;

[0023] Figure 15 This is a force analysis diagram of a target array sensing model in one embodiment of a flexible array sensor according to this application;

[0024] Figure 16 This is a surface force analysis diagram of a sensing model in one embodiment of a flexible array sensor according to this application;

[0025] Figure 17 This is a surface force analysis diagram of a target array sensing model in one embodiment of a flexible array sensor according to this application;

[0026] Figure 18 This is a surface force analysis diagram of a sensing model in one embodiment of a flexible array sensor according to this application;

[0027] Figure 19 This is a surface force analysis diagram of a target array sensing model in one embodiment of a flexible array sensor according to this application;

[0028] Figure 20 This is a schematic diagram of the structure of an embodiment of a sensing system according to this application;

[0029] Figure 21 This is a schematic diagram of multiple coordinate systems established on the sole of a sensing shoe in one embodiment of this application;

[0030] Figure 22 This is a schematic diagram of a simplified foot model established in one embodiment of a sensing shoe according to this application;

[0031] Figure 23 This is a schematic diagram showing the correspondence between the metatarsophalangeal joint area and the sole in one embodiment of a sensing shoe according to this application. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly set on the other component; when a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to the other component.

[0034] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" or "several" means two or more, unless otherwise explicitly specified.

[0036] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0037] Figures 1-6 This application illustrates a specific embodiment of a flexible array sensor, which includes multiple sensing units 1 arranged in an array. Each sensing unit 1, from top to bottom, includes a loading block 11, a first electrode plate 12, a dielectric layer 13, a second electrode plate 14, and a substrate 15. The loading block 11 is tightly fitted to the first electrode plate 12 to transmit external force to the first electrode plate 12, causing deformation of the dielectric layer 13. The first electrode plate 12 and the second electrode plate 14 are parallel to each other. The first electrode plate 12 includes multiple first working electrodes 21 arranged in an array symmetrically, with each first working electrode 21 in a first direction connected in series. The second electrode plate 14 includes multiple second working electrodes 41 arranged in an array symmetrically, with each second working electrode 41 in a second direction connected in series, and the first and second directions are orthogonal. The center positions of each first working electrode 21 and its corresponding second working electrode 41 coincide. The dielectric layer 13 separates the first electrode plate 12 and the second electrode plate 14. The substrate 15 is tightly fitted to the second electrode plate 14.

[0038] In this embodiment, the center positions of the first working electrode 21 and the corresponding second working electrode 41 coincide, and they are separated by a dielectric layer 13 to form a capacitor. This allows the multidimensional force experienced by the corresponding sensing unit 1 to be calculated based on the change in the distance between the first working electrode 21 and the corresponding second working electrode 41. Simultaneously, by sequentially connecting the first working electrodes 21 in the first direction and the second working electrodes 41 in the second direction in series, an orthogonal electrode array is achieved. Sensor data is read by selecting rows and columns.

[0039] like Figure 2As shown, the foot is divided into multiple distinct regions based on detailed anatomical features and biomechanical functions. The distribution of multiple array-type sensing units 1 in each plantar pressure zone is also displayed, including 9 units in region MH, 9 units in region LH, 3 units in region T1, 3 units in region T2, 3 units in region T3, 2 units in region T45, 3 units in region M1, 3 units in region M2, 3 units in region M3, 3 units in region M4, 3 units in region M5, and 20 units in region MF. Three-dimensional force measurements are performed at 64 points on these 64 sensing units 1 of the flexible array sensor in this embodiment, which helps to more accurately assess foot function and health.

[0040] like Figure 1 and Figure 2 As shown, the loading block 11 of the sensing unit 1 is square. According to the size requirements of the sensing unit 1, the side length of the loading block 11 is 10mm, the height is 2mm, and the distance between adjacent loading blocks 11 is 12mm.

[0041] Furthermore, the area of ​​the flexible array sensor is 230 cm². 2 The total area of ​​the 64 loading blocks 11 arranged in an array is 64 cm². 2 That is, the density of loading block 11 is 0.27 blocks / cm³. 2 .

[0042] In other embodiments, the flexible array sensor and the loading block 11 may also be of other sizes, as long as they meet the actual measurement requirements.

[0043] like Figure 1 and Figure 3 As shown, the first electrode plate 12 includes four first working electrodes 21 symmetrically distributed in a 2×2 array, and the second electrode plate 14 includes four second working electrodes 41 symmetrically distributed in a 2×2 array.

[0044] Combination Figure 4 The first electrode plate 12 and the second electrode plate 14 are arranged in two rows and two columns orthogonally, respectively. Each row and column of electrode plates has two electrodes connected in series. The center positions of each electrode of the first electrode plate 12 and the second electrode plate 14 coincide, forming a total of four parallel plate capacitors C11, C12, C21 and C22.

[0045] In this embodiment, the sensing unit 1 is formed by covering the array electrodes with a loading block 11 and decoupling the array capacitance (C11, C12, C21, and C22) formed by the array electrodes. When subjected to multidimensional forces, the tangential force component causes the dielectric layer 13 to undergo asymmetric deformation around the center of the loading block 11. This asymmetric deformation causes the array capacitance to change to different degrees. By decoupling based on these different degrees of change, the normal and tangential components of the multidimensional forces can be obtained.

[0046] like Figure 1 and Figure 5 As shown, in a flexible array sensor, multiple sensing units 1 distributed in an array correspond to multiple first electrode plates 12 and multiple second electrode plates 14 distributed in an array, and the multiple first electrode plates 12 and multiple second electrode plates 14 respectively contain 256 first working electrodes 21 and 256 second working electrodes 41, for a total of 512 electrodes. Figure 5 (a) shows 256 first working electrodes 21 connected in a first direction to form 16 rows of first working electrode strings, and each row of first working electrode strings is composed of 16 first working electrodes 21 connected together. Figure 5 (b) shows 256 second working electrodes 41 connected in a second direction to form 16 columns of second working electrodes, and each column of second working electrodes is composed of 16 second working electrodes 41 connected together.

[0047] In this embodiment, the series connection between multiple first electrode plates 12 is row series connection, and the series connection between multiple second electrode plates 14 is column series connection. Through the orthogonal arrangement of the first working electrodes 21 in the multiple first electrode plates 12 and the second working electrodes 41 in the multiple second electrode plates 14, 256 parallel plate capacitors are formed in the flexible array sensor. The 256 parallel plate capacitors form a 16×16 (16 rows, 16 columns) flexible array parallel plate capacitor.

[0048] like Figure 6 As shown, the first electrode plate 12 is a four-layer plate, consisting of, from top to bottom, a first layer, a second layer, a third layer, and a fourth layer. Figure 6 As shown in (a), the first layer is the top layer of the first electrode plate 12; as Figure 6 As shown in (b) and (c), the second layer is tightly bonded to the first layer, and the third layer is tightly bonded to both the second and fourth layers. Furthermore, the second and third layers of the multiple first electrode plates 12 form a signal conductor path area, used to realize series connection between the multiple first electrode plates 12; as shown... Figure 6 As shown in (d), the fourth layer is the bottom layer of the first electrode plate 12 and is designed as an electrode copper-clad window area for contact with the dielectric layer 13.

[0049] Furthermore, the second electrode plate 14 is also a four-layer plate, which includes, from top to bottom, the fifth layer, the sixth layer, the seventh layer and the eighth layer; the fifth layer is the top layer of the second electrode plate 14 and is designed as an electrode copper-clad window area for contact with the dielectric layer 13; the sixth layer is tightly attached to the fifth layer, and the seventh layer is tightly attached to the sixth and eighth layers, and the sixth and seventh layers of multiple second electrode plates 14 form a signal conductor path area for realizing the series connection between multiple second electrode plates 14; the eighth layer is the bottom layer of the second electrode plate 14.

[0050] In this embodiment, a Faraday cage is arranged around the electrodes and signal wire paths, i.e., a 45° grid copper grounding, and each layer of the first electrode plate 12 and the second electrode plate 14 is provided with vias to enable the conduction of the Faraday cage. All signal wires are ultimately connected to the signal acquisition circuit via USB Type-C.

[0051] In this embodiment, both the first working electrode 12 and the second working electrode 14 are square with a side length between 2mm and 5mm. The lateral and longitudinal spacing between each first working electrode 12 and each second working electrode 14 is between 2mm and 6mm.

[0052] Furthermore, the side length of the first working electrode 12 and the second working electrode 14 is 4mm, and the lateral and longitudinal spacing between each first working electrode 12 and each second working electrode 14 is 5mm.

[0053] To address the common crosstalk problem in array-type pressure sensors, capacitive sensor arrays, unlike resistive sensor arrays, have different sources of crosstalk. While capacitive sensor arrays do not exhibit the equivalent resistance generated during scanning gating as resistive sensor arrays, their crosstalk originates from the antenna effect between the array electrodes. Therefore, when designing capacitive sensor arrays, electromagnetic shielding of the array electrodes must be implemented, adhering to electromagnetic shielding design principles.

[0054] like Figure 5 As shown, the edges of the first working electrode 12 and the second working electrode 14 are both provided with rounded corners for electromagnetic shielding. These rounded corners can prevent the electrode plate from generating a sharp antenna effect, which would cause the surrounding electrodes to generate induced charges and bring about electromagnetic crosstalk.

[0055] In this embodiment, the loading block 11, dielectric layer 13 and substrate 15 are made of a first flexible material, the first electrode plate 12 and the second electrode plate 14 are made of a second flexible material, and the Young's modulus of the second flexible material is much greater than that of the first flexible material.

[0056] Furthermore, the first flexible material is Mold Star 31T (Smooth-on), an easy-to-use Shore 30A translucent platinum silicone. The second flexible material is polyimide (PI), with a Young's modulus of 69 MPa, which is much greater than the Young's modulus of 0.5 MPa of Mold Star 31T, the constituent material of dielectric layer 13. This makes the deformation of the second electrode plate 14 much smaller than that of dielectric layer 13, and the second electrode plate 14 can be regarded as a rigid substrate.

[0057] In this embodiment, the loading block 11 serves as the contact surface where the foot interacts with the shoe. Its material is Mold Star 31T, and its excellent rebound properties allow it to primarily convert the multidimensional array mechanical information of the foot and shoe into elastic potential energy. The electrode layer, composed of multiple arrayed first electrode plates 12 and multiple second electrode plates 14, is a PI material flexible printed circuit board (FPC), mainly used to collect the charge of the parallel plate capacitor.

[0058] Furthermore, the sensing unit 1 used in this application has a maximum range of 1500 kPa in the normal direction and 200 kPa in the tangential direction, which meets the requirements of plantar pressure analysis.

[0059] Furthermore, the thickness of the first electrode plate 12 and the second electrode plate 14 is only 500 μm, so their deformation is negligible. According to the Saint-Venant principle, the deformation of the intermediate loading region has a negligible effect on the deformation of the edges of the sensing unit 1, and the periphery of the sensing unit 1 can be rigidly fixed. The dielectric layer 13, as the main body for generating deformation of the sensing unit 1, mainly converts the external force applied to the loading block 11 into deformation. This deformation causes a change in the capacitance value of the parallel plate capacitor composed of the first working electrode 21, the second working electrode 41, and part of the dielectric layer 13, ultimately converting the external force into a change in the parallel plate capacitance.

[0060] like Figure 1 and Figure 3 As shown, the dielectric layer 13 includes a plurality of quadrangular truncated pyramids arranged in an array symmetrically. The top and bottom of the quadrangular truncated pyramids are respectively connected to the copper-clad window areas of the first electrode plate 12 and the second electrode plate 4.

[0061] Furthermore, the dimensions of the top and bottom of the quadrangular frustum are 1mm (length) × 1mm (width) and 3mm (length) × 3mm (width), respectively, and the height of the quadrangular frustum is 2mm.

[0062] It should be noted that traditional conical structures suffer from localized stress concentration and physical damage due to contact at the pointed ends under stress, while a truncated pyramid with a flat top is less prone to saturation under large loads. Therefore, this application uses a truncated pyramid array made of Mold Star 31T as the dielectric layer 13 to convert the elastic potential energy of the loading block 11 under external force into positional changes between the capacitor plates, thus enabling the sensing unit 1 to have a larger range. Furthermore, similar to a conical structure, the truncated pyramid is easily compressed under stress, thereby giving the sensing unit 1 higher sensitivity, meeting the requirements for large range, high sensitivity, and fast dynamic response in multidimensional foot force measurement.

[0063] In this embodiment, a flexible capacitive pressure sensor based on parallel plate capacitors models the dielectric layer deformation of a single capacitor and the external force it experiences. The capacitor is similar to a compressed spring structure; the pressure it experiences is proportional to its deformation. That is, the external force applied to the loading block 11 generates elastic potential energy and pressure within the loading region of the first electrode plate 12. The pressure on the loading block 11 compresses the dielectric layer 13, reducing the distance between the first electrode plate 12 and the second electrode plate 14, thus changing the capacitance value. Therefore, the applied external force can be calculated by detecting the capacitance change.

[0064] like Figure 7 As shown, the sensing unit 1 is first linearized and modeled to obtain the sensing model. This sensing model includes a loading body and four supporting springs covering the loading body. Each supporting spring represents a capacitive sensor, and the centers of the four supporting springs are the same as the center of the loading body. In the flexible array sensor, the rate of change of each capacitor with respect to the electrode spacing is equal, corresponding to the equal elastic coefficients of each supporting spring in the sensing model. Two tangential and one normal coordinate axes (x, y, and z axes) are defined. When an external force acts on the loading body, the external force F can be decomposed into two tangential forces Fi. x F y And a normal force F z This facilitates the calculation of the effect of the three axial force components on the capacitor.

[0065] Furthermore, a force analysis is performed on sensing unit 1 in a static measurement environment. At this time, the sensing model is in a horizontal state, and the weight of the loading body and the supporting springs creates a force balance. All supporting springs are compressed and generate elastic force. The force situation under this condition can be expressed as:

[0066] ;

[0067] Where m represents the mass of each supporting spring, and M represents the mass of the loading body. Indicates the spring constant of the supporting spring; This represents the distance between the first and second electrode plates in the initial state of sensing unit 1, and also represents the initial length of all supporting springs. Furthermore, it allows for the determination of... Solving for the problem yields:

[0068] .

[0069] like Figure 8 As shown, the force analysis diagram of the loading body in the sensing model when subjected to external forces in different directions is displayed.

[0070] like Figure 8 As shown in (a), when a tangential force in the x-axis direction is applied to the loading body... When the loading block is compressed, the elastic potential energy generated is transferred to the first electrode plate and the dielectric layer along the x-axis, and a torque is generated along the x-axis. This torque can be expressed as:

[0071] ;

[0072] in, The elastic modulus is the elastic coefficient in the x-axis direction; This refers to the height of the loading block, and also the distance between the centers of the top plates (corresponding first working electrodes) of two adjacent capacitors. Torque and rotation angle It can be approximated as:

[0073] ;

[0074] ;

[0075] At this time, C along the x-axis 11 and C 12 The dielectric layer deformation between them is greater than C 21 and C 22 The dielectric layer between them deforms, where, The difference in average dielectric layer thickness between the two sets of capacitors in the x-direction:

[0076] ;

[0077] simultaneous formula to , It can be represented as:

[0078] .

[0079] like Figure 8 As shown in (b), similarly, when a tangential force in the y-axis direction is applied to the loading body... When the loading block is compressed, the elastic potential energy generated is transferred to the first electrode plate and the dielectric layer in the y-axis direction, and a torque is generated in the y-axis direction. At this time, C along the y-axis 11 and C 21 The dielectric layer deformation is greater than C 12 and C 22 The dielectric layer deformation, It can be represented as:

[0080] .

[0081] in, This is the elastic coefficient in the y-axis direction. To correct for capacitance offset, this application defines the Relative Effective Gap Distance (REGD) as the difference between the current Effective Gap Distance (EGD) and its initial value. .Will and Rewritten in Hooke's Law form:

[0082] ;

[0083] .

[0084] like Figure 8 As shown in (c), when a normal force in the z-axis direction is applied to the loading body... At this time, the elastic potential energy generated by the compression of the loading block is uniformly transferred along the z-axis to the first electrode plate and the dielectric layer. 11 C 12 C 21 and C 22 The dielectric layer deformation is the same. It can be represented as:

[0085] ;

[0086] in, The elastic modulus is the coefficient of elasticity in the z-axis direction.

[0087] Combination Figure 8 and Figure 9 The external force F applied to the loading body can be represented by a simplified sensing model, that is, the components of the external force F based on the strain and elastic coefficient of each spring. , and a normal force Decouple. Figure 9 The red rectangles indicate the degree of compression of dielectric layer 13 at each parallel plate capacitor. When an external force of the same direction along the z-axis and x and y axes is applied simultaneously to the loading block, the loading block experiences... Upon compression, the elastic potential energy generated is transferred along the z-axis direction to the first electrode plate and the dielectric layer, generating a torque along the z-axis direction. At this time, C 11 C 12 C 21 and C 22 The dielectric layer deformation is the same. Based on this, the loaded block is subjected to... , Upon compression, the generated elastic potential energy is transferred to the first electrode plate and the dielectric layer in the x-axis and y-axis directions, generating torques along the x-axis and y-axis directions. At this time, C along the 45° direction of the x-axis and the 45° direction of the y-axis 11 The dielectric layer deformation is greater than C 12 C 21 and C 22 The dielectric layer deformation, C 11 The change in capacitance C 12 C 21 C 22 The change in capacitance. Now, select C. 11 As a reference capacitor 、 and It can be represented as:

[0088] .

[0089] like Figure 10 As shown, the sensing models are arrayed and combined to obtain the initial array sensing model corresponding to the flexible array sensor. The initial array sensing model contains n 2 Each sensor model includes one loading body and four supporting springs. The force situation of the flexible array sensor in a static measurement environment is analyzed. In this case, all supporting springs are compressed and generate elastic force, and the weight of the loading body and supporting springs creates a force balance. The force situation under this condition can be expressed as:

[0090] ;

[0091] Where m represents the mass of each supporting spring; M represents the mass of the loading body; In the initial state of the flexible array sensor, the distance between the first and second electrode plates in each sensing unit also represents the initial length of all supporting springs, thus enabling the determination of the initial length of all supporting springs. Solving for the problem yields:

[0092] .

[0093] like Figure 11 As shown, when a uniformly distributed force along the z-axis is applied to the loading body corresponding to all sensing units of the flexible array sensor... At that time, the dielectric layer deformation of all sensing units is the same. It can be represented as:

[0094] ;

[0095] At this time, the applied external force There is no torque in the x-axis and y-axis directions, meaning there is no stress inside the flexible array sensor.

[0096] like Figure 12 As shown, when the loading blocks of all sensing units of the flexible array sensor simultaneously apply an external force in the x-axis direction... At that time, external force The torque generated along the x-axis is based on the position of each sensing unit relative to the center of the flexible array sensor. This torque can be expressed as:

[0097] ;

[0098] in, is the elastic coefficient in the x-axis direction; l is the height of the loading body (loading block), and also the distance between the centers of the top electrode plates (corresponding first electrode plates) of two adjacent capacitors. The torque of each sensing unit... and rotation angle It can be approximated as:

[0099] ;

[0100] ;

[0101] At this time, C of each sensing unit along the x-axis direction 11 and C 12 The dielectric layer deformation is greater than C 21 and C 22 The dielectric layer deformation, in which, The difference in average dielectric layer thickness between the two sets of capacitors in each sensing unit along the x-direction:

[0102] ;

[0103] United to Then the effect on each sensing unit It can be represented as:

[0104] ;

[0105] Among them, the resultant force of the flexible array sensor in the x-axis direction With each sensing unit It has the following relationship:

[0106] .

[0107] like Figure 13 As shown, similarly, when all loading bodies corresponding to the flexible array sensor simultaneously apply an external force in the y-axis direction... At that time, external force The torque generated along the y-axis by the sensing unit relative to the center position of the flexible array sensor. This torque can be expressed as:

[0108] ;

[0109] in, is the elastic coefficient in the y-axis direction; l is the height of the loading body (loading block), and also the distance between the centers of the top plates (corresponding first working electrodes) of two adjacent capacitors. The torque of each sensing unit... and rotation angle It can be approximated as:

[0110] ;

[0111] ;

[0112] At this time, C of each sensing unit along the y-axis direction 11 and C 12 The dielectric layer deformation is greater than C 21 and C 22 The dielectric layer deformation, in which, The difference in average dielectric layer thickness between the two sets of capacitors in each sensing unit along the y-axis direction:

[0113] ;

[0114] United to The effect on each sensing unit It can be represented as:

[0115] ;

[0116] Among them, the resultant force of the flexible array sensor in the y-axis direction With each sensing unit It has the following relationship:

[0117] .

[0118] Furthermore, crosstalk exists in flexible array sensors during use. When a normal force is applied to the loading block, the work done by the normal force cannot be completely converted into the strain energy of the first electrode plate and the elastic potential energy of the truncated quadrangular array in the dielectric layer. At this time, some of it is still conducted to the surrounding sensing units. Therefore, the initial array sensing model can be optimized into the target array sensing model.

[0119] like Figure 14As shown, in the target array sensing model, the sensing models are connected by internal crosstalk springs to characterize the internal crosstalk of the entire flexible array sensor. The target array sensing model contains n... 2 There are n sensing models, each consisting of one loading body and four supporting springs. 2 The sensing model contains a total of 2n×(n-1) internal crosstalk springs. When the forces generated by the weight of the loading body, the supporting springs, and the internal crosstalk springs are balanced, all the supporting springs and internal crosstalk springs will compress and generate elastic force. The force situation in this case can be expressed as:

[0120] ;

[0121] in, The spring constant of the support spring is represented by m; the mass of the support spring is represented by M; the mass of the loading body is represented by m1; and the mass of the internal crosstalk spring is represented by m1.

[0122] like Figure 15 As shown, the external force applied to a certain sensing model The crosstalk compresses its internal crosstalk spring, causing deformation and creating a force balance. In this case, the force situation of the sensing model can be expressed as:

[0123] ;

[0124] At this point, the internal crosstalk springs of adjacent sensing models are compressed and deformed, applying external forces to the adjacent sensing models and forming a force balance. The force situation in this case can be expressed as:

[0125] ;

[0126] in, The spring constant of the internal crosstalk spring. , and The angular offset generated by the strain of the internal crosstalk spring is used only for force analysis. Based on the above force conditions, it can be seen that applying an external force to a certain sensing model... The forces generated by all sensing models are defined as follows: The crosstalk in the sensing model is simplified to a linear factor. Apply external force to each sensor model in the target array sensor model. Establish a system of linear equations:

[0127] ;

[0128] By solving this system of linear equations, the overall crosstalk characteristic matrix K can be obtained. The actual measurement value of the flexible array sensor is... Measurement values ​​can be established. Compared with the true value The compensation relationship between them can be used. The crosstalk characteristic matrix K can be used to analyze the sensor output in practical applications. Compensation is performed to obtain the compensated true output value. This improves measurement accuracy.

[0129] Furthermore, when the flexible array sensor is loaded onto a curved surface, internal stress is generated due to bending deformation, causing the initial state of the sensing model to differ from that when loaded on a planar surface. In its initial state, the dielectric layer composed of the truncated pyramid array is not compressed, and no internal stress is generated. However, when the flexible array sensor is loaded onto a curved surface, its entire structure undergoes bending deformation, causing the first electrode plate to be stretched and generate internal stress due to the bending of the sensor. Most of the internal stress generated by the stretching of the first electrode plate is converted into the elastic potential energy of the dielectric layer composed of the truncated pyramid array, thus causing the dielectric layer to be compressed. However, the Young's modulus of the first and second electrode plates is much larger than that of the dielectric layer composed of the truncated pyramid array, resulting in minimal strain after stretching. Therefore, it can be assumed that the dimensions of the first and second electrode plates do not change during the bending process.

[0130] like Figure 16 As shown, when a single sensing model in the xOz plane bends by an angle α, both the first and second electrode plates rotate α / 2 around the z-axis. At this time, unlike the force balance along the z-axis in the static measurement environment, a force balance also forms along the x-axis in the bending measurement environment. Therefore, the force balance along the z and x-axis in the bending measurement environment can be expressed as:

[0131] ;

[0132] in, This represents the initial distance between the first and second electrode plates in the sensing unit during bending measurement, which can be solved. have to:

[0133] ;

[0134] In a bending measurement environment, the deformation direction inside the dielectric layer is perpendicular to the inclined plane, and the angle between this direction and the force direction of the sensing unit is α / 2. Compared to a non-bending measurement environment, the relative effective gap distance REGD in the sensing unit is:

[0135] ;

[0136] Compared to the initial distance of the sensor unit's plates in a static measurement environment The initial distance between the plates of the sensing unit in the bending measurement environment Due to the influence of the bending angle, it is greater than According to the definition of the capacitance value of the sensing unit, the initial capacitance in a bending measurement environment is greater than that in a static measurement environment. When the sensing unit is in a bending measurement environment, the relative effective gap distance REGD will decrease and vary with the bending angle when the same external force is applied to the loading block. Therefore, the three-dimensional force in a bending environment can be expressed as:

[0137] .

[0138] like Figure 17 As shown, for the target array sensing model corresponding to the flexible array sensor, an analysis is performed by applying a normal surface load in the xOz plane. With all sensing units fully in contact with the surface load, sensing models S1 and S3 are parallel to the tangent direction at their contact points with the surface load. The extension of this tangent direction forms an angle α / 2 with the z-axis. Sensing model S2 is parallel to the x-axis. It is noteworthy that only the sensing model at the middle point bends. Unlike the force balance along the z-axis in the static measurement environment, a force balance also forms along the x-axis in the bending measurement environment. The force along the normal direction of sensing model S2 at the bending point is shown below. for:

[0139] ;

[0140] Compared to the sensing model at the bend, the other sensing models are not in a bend. At this point, the supporting force along the vertical direction of the inclined plane is between sensing models S1 and S3, which are not in a bend. and for:

[0141] ;

[0142] The curved surface load is decomposed into Lo1, Lo2, and Lo3 according to the positional relationship of sensing models S1, S2, and S3, respectively. Sensing models S1 and S3 provide support forces for the curved surface loads Lo1 and Lo3. , Frictional forces Ff1 and Ff3, and supporting force , Frictional forces Ff1 and Ff3 are the tangential and normal forces measured by sensing models S1 and S3, respectively. For the overall analysis of the curved surface load, the supporting force... , , The frictional forces Ff1 and Ff3 balance each other in the x and z axes. Therefore, the following surface force model can be established for the sensing model and the surface load:

[0143] ;

[0144] Flexible array sensors can be viewed as a continuum. The physical quantity used to describe the curvature of this continuum is curvature, which is the rate of rotation of the tangent angle at a point on the continuum's curve with respect to the arc length. Curvature is a measure of the degree of unevenness of the continuum. Mean curvature is a physical quantity used to describe the overall curvature of the continuum; it can be expressed as the tangent angle of the arc. With the arc length The absolute value of the ratio, the definition of mean curvature is as follows:

[0145] ;

[0146] The radius of curvature R, as the reciprocal of the curvature, can be expressed as:

[0147] ;

[0148] However, the curved surface load described in the above formula represents an ideal situation, where the bending arc length is infinitesimally small and the curvature is infinitely large at that angle. Conversely, at the same angle, when the curvature is infinitesimally small, the bending arc length is infinitely large. For a sensing model with finite dimensions, the bending arc length is approximately planar. Therefore, for a curved surface load with unknown curvature, the bending angle cannot be determined based on the rate of change of capacitance.

[0149] like Figure 18 As shown in (a) and (b), according to It can be seen that, within a certain sensor bending arc length In this case, the radius of curvature is inversely proportional to the bending angle. Therefore, the three-dimensional force-bending working condition solution model based on the sensing model, according to... The force along the normal direction of the sensing model S2 at the bend. It can be rewritten as:

[0150] ;

[0151] Based on the property that the trigonometric function sec exhibits a monotonically increasing positive correlation in the interval [0, π / 2], it can be considered that... It is inversely proportional to the radius of curvature R.

[0152] like Figure 19The figure shows the relationship between the radius of curvature R and the bending of the sensing model at a certain bending angle θ. At this point, sensing model S2 is under surface load. According to the formula above, it is impossible to perform three-dimensional force calculations on the sensing model when the curvature of the surface load is unknown. The support force factors for sensing models S1, S2, and S3 under the radius of curvature R and bending angle α can be defined. , and The force model of the curved surface can be rewritten in the following form:

[0153] ;

[0154] Wherein, Fn1, Fn2, and Fn3 are the solution values ​​of sensing models S1, S2, and S3, respectively.

[0155] Furthermore, this can be achieved through the support factor. , and Optimization of the solution values ​​of sensing models S1, S2 and S3 under curved surface load.

[0156] To solve for the support force factor, this application establishes a Gaussian distribution model of the radius of curvature R, bending angle α, and the support force factor of sensing models S1, S2, and S3, which is used to fit the radius of curvature, bending angle, and the support force factor of the sensing models. First, the probability density function of the one-dimensional Gaussian distribution is shown below:

[0157] ;

[0158] in, The mean of the distribution. The variance of the distribution can be described by the mean and variance of the variables. It is the location parameter of a one-dimensional Gaussian distribution, describing the location of the central tendency of the one-dimensional Gaussian distribution. Describes the degree of dispersion of one-dimensional Gaussian distributed data. The larger the size, the more dispersed the data distribution. The smaller the value, the more concentrated the data distribution.

[0159] Then the support factor distribution of the sensing model It can be expressed in the following form:

[0160] ;

[0161] Where x is the position of the sensing model in the xOz plane. Let be the support force distribution factor of the sensing model in the xOz plane, defined at the bending angle. The inverse proportional relationship with the radius of curvature R The variance of a one-dimensional Gaussian distribution is used to describe the support force factor of the sensing model in the one-dimensional xOz plane. The degree of dispersion. Ultimately, it can be achieved through... , and ,right Solve the problem.

[0162] Based on the same inventive concept, such as Figure 20 As shown, the present invention also provides a sensing system, which includes two flexible array sensors as described above, and the two flexible array sensors are fixedly connected through a plurality of corresponding substrates for simultaneously sensing multidimensional forces on both sides.

[0163] In this application, other technical features of the above-described sensing system are the same as those disclosed in the above-described method embodiments, and will not be repeated here.

[0164] Based on the same inventive concept, such as Figure 20 As shown, this application also provides a sensing shoe, which includes an upper and a sole composed of the aforementioned sensing system. One flexible array sensor (foot-shoe interface) is used to contact the sole to detect multi-dimensional pressure in the sole area, with the measurement unit being kPa; the other flexible array sensor (shoe-ground interface) is used to contact the ground to detect the overall three-dimensional ground reaction force, with the measurement unit being N.

[0165] In this application, the sensing shoe can simultaneously detect multi-dimensional pressure between the foot and the shoe and three-dimensional ground reaction force between the shoe and the ground, thus meeting the needs of plantar pressure analysis.

[0166] like Figure 21 As shown, a right-handed coordinate system {O} is established for the flexible array sensors corresponding to the foot-shoe interface and shoe-ground interface of the right foot. F-insole} and {O F-sole}. Among them, {O F-insole} and {O F-sole The origin O of} F-insole and O F-sole Located at the junction of the heel edges LH and MH on their respective interfaces, the z-axis (V direction) is perpendicular to the second electrode plate, and the x-axis (ML direction) and y-axis (AP direction) are perpendicular to each other. The standard coordinate system {O} F} is located in {O F-insole} and {O F-sole At the center of the z-axis of {O}, at a distance of H. F-insole} and {O F-sole In the coordinate system of each sensing unit, {O}, the coordinate system is {O}. Urc}, where r represents the row, c represents the column, and r∈[1,8], c∈[1,8].

[0167] Because the elastic modulus of the first electrode plate 12 and the second electrode plate 14 in the flexible array sensor is much greater than that of the dielectric layer 13, the torsional force applied to the loading block 11 cannot cause the first electrode plate 12 and the second electrode plate 14 in the flexible array sensor to undergo torsional deformation, that is, the sensing unit cannot rotate around O. Urc The z-axis rotates.

[0168] like Figure 22 As shown, this application also proposes a simplified foot model based on the physiological characteristics of the foot joints. This model includes a rotation axis with O as the center of rotation and R as the radius of rotation for the metatarsophalangeal joint. This rotation axis is connected to the phalanges and metatarsals, respectively, and the size of the metatarsophalangeal joint is correlated with shoe size. When the foot is in close contact with the foot-shoe interface, the radii of rotation for the foot-shoe interface and the shoe-ground interface are R and R, respectively. insole With R sole , where R insole The same as the size R of the metatarsophalangeal joint, R sole It is the sum of the metatarsophalangeal joint dimension R and the distances (2H) between the foot-shoe interface and the shoe-ground interface.

[0169] However, the ideal situation is that the foot is in close contact with the foot-shoe interface. In reality, the rotation radius of the foot-shoe interface and the shoe-ground interface cannot be determined during walking. At the same time, the metatarsophalangeal joint of the flexible array sensor makes contact with the ground simultaneously during plantar flexion, but there is a situation where the loading surface is not parallel to the ground.

[0170] like Figure 23 As shown in (a) and (b), in the foot-shoe interface and the shoe-ground interface, {O F-insole} and {O F-sole The T1~T5 regions of} correspond to the metatarsophalangeal joint region, respectively, and are used to optimize the {O} during plantar flexion. F-insole} and {O F-sole Three-dimensional force calculation of {O} F-insole} and {O F-sole The three-dimensional force in the T1~T5 region of} can be expressed as:

[0171]

[0172]

[0173] For any sensing unit Lo rc The pressures applied to the loading block along the x, y, and z axes can be calculated as follows:

[0174]

[0175] Among them, S rcThis is the area of ​​the working plane, and it is equal to the projected area of ​​the loading block on the surface of the first electrode plate. For any sensing unit Lo... rc The resultant force of the flexible array sensor in the x, y, and z axes can be expressed as:

[0176] ;

[0177] .

[0178] Therefore, this invention discloses a flexible array sensor, a sensing system, and a sensing shoe. The flexible array sensor includes multiple sensing units arranged in an array. Each sensing unit, from top to bottom, includes a loading block, a first electrode plate, a dielectric layer, a second electrode plate, and a substrate. The loading block is tightly attached to the first electrode plate to transfer external force to the first electrode plate, causing deformation of the dielectric layer. The first and second electrode plates are parallel to each other. The first electrode plate includes multiple first working electrodes arranged in an array symmetrically, with each first working electrode in a first direction connected in series. The second electrode plate includes multiple second working electrodes arranged in an array symmetrically, with each second working electrode in a second direction connected in series. The first and second directions are orthogonal, and the center positions of each first working electrode and its corresponding second working electrode coincide. The dielectric layer separates the first and second electrode plates. The substrate is tightly attached to the second electrode plate. This flexible array sensor features high pressure measurement accuracy and high spatial resolution. Furthermore, the sensing system and sensing shoe composed of this flexible array sensor can simultaneously collect multidimensional forces between the foot and shoe / shoe and the ground, and calculate the pressure in each zone of the sole.

[0179] The above are merely embodiments of this application and do not limit the scope of this patent application. Any equivalent structural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A flexible array sensor, characterized by, The sensor unit includes a loading block, a first electrode plate, a dielectric layer, a second electrode plate and a substrate in sequence from top to bottom. The loading block is tightly attached to the first electrode plate, and is used to transmit external force to the first electrode plate and cause the dielectric layer to deform. The first electrode plate and the second electrode plate are parallel to each other, the first electrode plate includes a plurality of first working electrodes arranged in an array and symmetrically, each first working electrode in a first direction is connected in series, the second electrode plate includes a plurality of second working electrodes arranged in an array and symmetrically, each second working electrode in a second direction is connected in series, the first direction is orthogonal to the second direction, and the center positions of each first working electrode and corresponding second working electrode coincide. The dielectric layer separates the first electrode plate and the second electrode plate, and includes a plurality of quadrangular prisms arranged in an array and symmetrically. The substrate is tightly attached to the second electrode plate. The flexible array sensor can be simplified as a target array sensor model for solving the posture of each sensing unit in the flexible array sensor; the target array sensor model includes n 2 sensing models, and 2n×(n-1) internal crosstalk springs are contained between n 2 sensing models.

2. The flexible array sensor of claim 1, wherein, The first electrode plate includes four first working electrodes arranged in a 2x2 array and symmetrically, and the second electrode plate includes four second working electrodes arranged in a 2x2 array and symmetrically.

3. The flexible array sensor of claim 1, wherein, The first electrode plate is a four-layer plate, including a first layer, a second layer, a third layer and a fourth layer in sequence from top to bottom. The first layer is the top layer of the first electrode plate. The second layer is tightly attached to the first layer, the third layer is tightly attached to the second layer and the fourth layer, and the second layer and the third layer of a plurality of first electrode plates form a signal wire via area for realizing series connection between a plurality of first electrode plates. The fourth layer is the bottom layer of the first electrode plate, and is designed as an electrode copper-clad opening area for contacting the dielectric layer.

4. The flexible array sensor of claim 3, wherein, The second electrode plate is a four-layer plate, including a fifth layer, a sixth layer, a seventh layer and an eighth layer in sequence from top to bottom. The fifth layer is the top layer of the second electrode plate, and is designed as an electrode copper-clad opening area for contacting the dielectric layer. The sixth layer is tightly attached to the fifth layer, the seventh layer is tightly attached to the sixth layer and the eighth layer, and the sixth layer and the seventh layer of a plurality of second electrode plates form a signal wire via area for realizing series connection between a plurality of second electrode plates. The eighth layer is the bottom layer of the second electrode plate.

5. The flexible array sensor of claim 1, wherein, The first working electrode and the second working electrode are both square, and the electrode edges of the first working electrode and the second working electrode are both provided with a round corner for electromagnetic shielding.

6. The flexible array sensor of claim 1, wherein, The top and bottom of the quadrangular prism are connected to the electrode copper-clad opening area of the first electrode plate and the second electrode plate respectively.

7. The flexible array sensor of claim 1, wherein, The loading block, the dielectric layer and the substrate adopt a first flexible material, the first electrode plate and the second electrode plate adopt a second flexible material, and the elastic modulus of the second flexible material is greater than that of the first flexible material.

8. The flexible array sensor of claim 2, wherein, Each of the sensing models includes one loading body and four supporting springs, when the self-gravities of the loading body, the supporting springs and the internal crosstalk spring form a balance of forces, all the supporting springs and the internal crosstalk spring will be compressed and generate elastic force, in this case, the force condition can be expressed as: ； wherein, represents the spring constant of the support spring; is the inter-plate distance between the first electrode plate and the second electrode plate in the initial state of the sensing unit, m represents the mass of the support spring, M represents the mass of the loading body, and m1 represents the mass of the internal cross-talk spring.

9. A sensing system characterized by, The system includes two flexible array sensors as claimed in any one of claims 1-8, and the two flexible array sensors are fixedly connected through a corresponding plurality of substrates, for simultaneously sensing multi-dimensional forces on both sides.

10. A sensing shoe characterized by, A shoe including an upper and a sole containing a sensing system as claimed in claim 9, wherein one of the flexible array sensors is used to contact with the foot bottom to detect multi-dimensional pressure of the foot bottom partition; and the other flexible array sensor is used to contact with the ground to detect the overall three-dimensional ground reaction force.

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