Capacitance detection method between automotive interior component and human body, sensing device having charge-receiving mapping layer, and hands-off detection steering wheel

Abstract

A capacitance detection method between an automotive interior component and a human body. The method comprises: heating an automotive interior component (1) via a metal wire (22) during a heating cycle; acquiring a human occupancy capacitance via the metal wire (22) during a sampling cycle; comparing the human occupancy capacitance with a capacitance threshold to obtain an occupancy status of the automotive interior component (1); and repeatedly executing the above process. Further provided are a sensing device having a charge-receiving mapping layer (4) and a hands-off detection steering wheel. Heating functionality and capacitance detection functionality are achieved by means of time-division multiplexing. In addition, by adding a conductive capacitance receiving layer (4) within the automotive interior component (1), the sensing area is increased, and detection sensitivity is improved.

Description

A method for detecting capacitance between an automotive interior part and a human body, a sensing device with a charge-accepting mapping layer, and a hands-off detection steering wheel

[0001] Cross Reference to Related Applications

[0002] The present application claims priority to a Chinese patent application No. 2024110861496, filed on August 8, 2024, entitled "A method for detecting capacitance between an automotive interior part and a human body";

[0003] and a Chinese patent application No. 2024110861477, filed on August 8, 2024, entitled "A sensing device with a charge-accepting mapping layer and a hands-off detection steering wheel", the contents of which are incorporated herein by reference in their entirety. TECHNICAL FIELD

[0004] The present application relates to the field of automotive technology, in particular to a method for detecting capacitance between an automotive interior part and a human body, a sensing device with a charge-accepting mapping layer, and a hands-off detection steering wheel. BACKGROUND

[0005] In the design of modern automobiles, there is an increasing demand for intelligent and humanized functions of automotive interior parts. Among them, accurately detecting the occupancy of interior parts (such as steering wheels, seats, etc.) by people in the car is of great significance. Traditional automotive interior part occupancy detection methods are often based on simple mechanical switches or pressure sensors, but these methods have many limitations. Mechanical switches are prone to wear and tear after long-term use, resulting in reduced detection reliability; pressure sensors perform poorly in terms of detection accuracy and response speed, making it difficult to meet the increasing user demands.

[0006] Occupancy sensors include a sheet-shaped substrate and metal wires disposed on the sheet-shaped substrate. With the development of technology, a detection method based on the principle of capacitance has emerged, that is, by forming a capacitance between the metal wires built-in the automotive interior part and the human body to determine the occupancy, as shown in FIG. 2, C1 in FIG. 2 is the sensing capacitance of the metal wires and the human body.

[0007] However, the existing capacitance detection scheme still needs to be improved in terms of sensitivity. In some complex use scenarios, there may be misjudgments or delayed responses, affecting user experience and the intelligent functions of the car.

[0008] SUMMARY

[0009] In view of the above-mentioned defects or shortcomings in the prior art, the present application provides a method for detecting capacitance between an automotive interior part and a human body, comprising the following steps:

[0010] S100. set an occupancy capacitance threshold, a sampling period and a heating period;

[0011] S200. heat the automotive interior part by the metal wire in the heating period, wherein the automotive interior part is provided with a human occupancy sensor, the human occupancy sensor is provided with a sheet-shaped substrate and the metal wire on the sheet-shaped substrate;

[0012] S300. acquire a human occupancy total capacitance by the human occupancy sensor in the sampling period, wherein the automotive interior part is further provided with a capacitance receiving layer with electrical conductivity, and the human occupancy total capacitance is obtained by induced capacitances between a human body and the metal wire, between the human body and the capacitance receiving layer, and between the metal wire and the capacitance receiving layer;

[0013] S400. compare the human occupancy total capacitance and the occupancy capacitance threshold to obtain a comparison result, the comparison result including a first comparison result and a second comparison result, the first comparison result representing that the automotive interior part is occupied when the human occupancy total capacitance is greater than or equal to the occupancy capacitance threshold, and the second comparison result representing that the automotive interior part is not occupied when the human occupancy total capacitance is less than the occupancy capacitance threshold;

[0014] S500. execute step S200;

[0015] S600. update the human occupancy total capacitance and execute steps S300-S400;

[0016] S700. repeat execution of steps S500-S600.

[0017] Optionally, the acquiring the human occupancy total capacitance by the human occupancy sensor in the sampling period includes the following steps:

[0018] S310. obtain a single sampling total capacitance according to a first induced capacitance, a second induced capacitance and a third induced capacitance, wherein the first induced capacitance is between a human body and the metal wire, the second induced capacitance is between the human body and the capacitance receiving layer, and the third induced capacitance is between the metal wire and the capacitance receiving layer;

[0019] S320. obtain the human occupancy total capacitance by a capacitance mean value strategy.

[0020] Optionally, the capacitance receiving layer is provided on a side of the metal wire away from the sheet-shaped substrate.

[0021] Optionally, the electric capacity receiving layer is arranged on any side of the metal wire, and the electric capacity receiving layer has weak conductivity to receive the electric charge mapped by the metal wire and expand the sensing area.

[0022] Optionally, a sheet substrate is arranged on any side of the metal wire, and the sheet substrate is made of non-conductive material, and the metal wire is arranged with the electric capacity receiving layer away from the sheet substrate.

[0023] Optionally, the metal wire is arranged with a glue layer away from the sheet substrate, and the glue layer is made of weakly conductive conductive glue, and the glue layer is the electric capacity receiving layer.

[0024] Optionally, the metal wire is arranged with a first glue layer away from the sheet substrate, and the first glue layer is arranged with a covering layer away from the metal wire, and the covering layer is a flexible sheet made of weakly conductive material, and the covering layer is the electric capacity receiving layer.

[0025] Optionally, the metal wire is adhered to the sheet substrate through a second glue layer, and the second glue layer is made of weakly conductive conductive glue, and the second glue layer is the electric capacity receiving layer.

[0026] Optionally, the sheet substrate has weak conductivity, and the sheet substrate is used as the electric capacity receiving layer.

[0027] Optionally, the metal wire is arranged with a skin away from the sheet substrate, and the skin is made of weakly conductive material, and the skin is the electric capacity receiving layer.

[0028] Optionally, the weakly conductive material is obtained by adding conductive fibers to carbonizing, printing, soaking conductive liquid, electroplating, or weaving fibers.

[0029] Optionally, the sheet resistance of the electric capacity receiving layer is between 10 3 -10 6 Ω.

[0030] Optionally, the electric capacity average strategy includes the following steps:

[0031] S321. Setting the number of single sampling;

[0032] S322. Obtaining a total electric capacity sequence, the total electric capacity sequence including a plurality of single sampling total electric capacities, and the number of single sampling total electric capacities of the total electric capacity sequence being the same as the number of single sampling;

[0033] S323. Taking an arithmetic mean of the total electric capacity sequence to obtain the total electric capacity of human occupation.

[0034] Optionally, updating the total electric capacity of human occupation includes the following steps:

[0035]

[0035] S610. Removing the first single-sampling total capacitance in the total capacitance sequence, and adding the single-sampling total capacitance obtained in the next sampling period at the end of the total capacitance sequence to obtain an updated total capacitance sequence;

[0036] S620. Calculating the updated total capacitance sequence by an arithmetic mean to obtain a next human-occupancy total capacitance, which is a first occupancy total capacitance;

[0037] S630. Updating the human-occupancy total capacitance in step S300 to the first occupancy total capacitance.

[0038] Optionally, the sum of the sampling period and the heating period is less than the product of the number of single sampling and the preset detection duration, so that the comparison result can be obtained at least once within the preset detection duration.

[0039] Optionally, the length of the heating period is 2.5 times or more of the length of the sampling period.

[0040] Optionally, the capacitance receiving layer has weak conductivity.

[0041] Optionally, the capacitance receiving layer has a strong conductive layer, and a strong dielectric layer is arranged between the strong conductive layer and the metal wire.

[0042] The embodiment of the present application also provides a sensing device with a charge receiving mapping layer, which comprises a pad body, and the pad body comprises:

[0043] a functional layer, the functional layer comprising at least a metal wire and an insulating layer, and the metal wire is configured to heat and sense;

[0044] an extension layer, the extension layer being arranged on any side of the metal wire, and the extension layer has weak conductivity to receive the charge mapped by the metal wire and expand the sensing area.

[0045] Optionally, the first surface on any side of the functional layer is provided with a base material, the base material is made of micro-conductive material, and the base material is the extension layer.

[0046] Optionally, any side of the metal wire is provided with a base material, the base material is made of non-conductive material, and the metal wire is provided with the extension layer away from the side of the base material.

[0047] Optionally, the metal wire is provided with an adhesive layer away from the side of the base material, the adhesive layer is made of weakly conductive conductive adhesive, and the adhesive layer is the extension layer.

[0048] Optionally, the metal wire is provided with a first adhesive layer away from the substrate side, the first adhesive layer is provided with a covering layer away from the metal wire side, the covering layer is a flexible sheet made of a micro-conductive material, and the covering layer is the extension layer.

[0049] Optionally, the metal wire is adhered to the substrate by a second adhesive layer, the second adhesive layer is made of a weakly conductive conductive adhesive, and the second adhesive layer is the extension layer.

[0050] Optionally, the sheet resistance of the extension layer is 10 3 -10 6 Ω.

[0051] Optionally, the sensing device further comprises a skin, the skin is arranged away from the substrate side of the metal wire, the skin is made of a micro-conductive material, and the skin is the extension layer.

[0052] Optionally, the micro-conductive material is obtained by adding conductive fibers to carburizing, printing, soaking conductive liquid, electroplating, or woven fibers.

[0053] The embodiment of the present application also provides a hand-off detection steering wheel, which comprises a steering wheel body, and the surface of the steering wheel body is provided with the sensing device with the charge receiving mapping layer.

[0054] In summary, the embodiment of the present application provides a capacitive detection method between an automotive interior part and a human body, the metal wire is used to heat the automotive interior part in a heating period, the human body occupancy sensor with the metal wire is used to obtain a total human body occupancy capacitance in a sampling period, and the total human body occupancy capacitance is compared with an occupancy capacitance threshold to obtain the occupancy of the automotive interior part, and the above process is repeatedly executed, so that the heating function and the capacitive detection function are realized by time division multiplexing. In addition, the capacitive receiving layer with conductivity is added in the automotive interior part, the sensing area is increased, the total human body occupancy capacitance is increased, and the sensitivity of capacitive detection is improved.

[0055] The embodiment of the present application provides a sensing device with a charge receiving mapping layer and a hand-off detection steering wheel, which comprises a functional layer, the functional layer at least comprises a metal wire and an insulating layer, the metal wire is configured to heat and sense, and an extension layer is arranged on any side of the metal wire, the extension layer has weak conductivity to receive the charge mapped by the metal wire and enlarge the sensing area.

[0056] Compared with the prior art, the application has the beneficial effects that the sensing device with the charge receiving and mapping layer can be arranged on a vehicle interior part such as a vehicle seat or a steering wheel, configured to sense information such as a human body occupying a seat or holding a steering wheel through a change in capacitance, and an extension layer with weak conductivity is arranged above or below the metal wire, so that capacitances are generated between the metal wire and the human body, between the metal wire and the extension layer, and between the extension layer and the human body, thereby increasing the inductive capacitance of the dual-frequency capacitance detection, improving the sensitivity of the dual-frequency capacitance detection occupancy technology, and improving the judgment accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0057] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present disclosure, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0058] Fig. 1 is a flowchart of a capacitance detection method between an automobile interior part and a human body according to an embodiment of the present application;

[0059] Fig. 2 is a structural schematic diagram of capacitance detection without a capacitance receiving layer when the automobile interior part is a vehicle seat in the prior scheme;

[0060] Fig. 3 is a structural schematic diagram of capacitance detection when the capacitance receiving layer is placed on the metal wire when the automobile interior part is a vehicle seat according to an embodiment of the present application;

[0061] Fig. 4 is a structural schematic diagram of an occupancy sensor and a capacitance receiving layer according to an embodiment of the present application;

[0062] Fig. 5 is a structural schematic diagram of capacitance detection when the sheet-shaped substrate is a capacitance receiving layer when the automobile interior part is a vehicle seat according to an embodiment of the present application;

[0063] Fig. 6 is a structural schematic diagram of a new sensor according to an embodiment of the present application;

[0064] Fig. 7 is a layout schematic diagram of a metal wire according to an embodiment of the present application;

[0065] Fig. 8 is a layout schematic diagram of a metal wire and a capacitance receiving layer according to an embodiment of the present application;

[0066] Fig. 9 is a circuit schematic diagram after adding a capacitance receiving layer according to an embodiment of the present application;

[0067] Fig. 10 is an equivalent circuit diagram of Fig. 9;

[0068] Fig. 11 is an exploded view of a structure of a sheet-shaped substrate as a capacitive receiving layer when the automotive interior part is a steering wheel;

[0069] Fig. 12 is an exploded view of a structure of a sheet-shaped substrate as a non-conductive material, with an additional capacitive receiving layer when the automotive interior part is a steering wheel.

[0070] Fig. 13 is a structure diagram of a sensing device with a charge receiving mapping layer provided by the embodiment of the present application (the extension layer is a substrate);

[0071] Fig. 14 is a structure diagram of a sensing device with a charge receiving mapping layer provided by the embodiment of the present application (the extension layer is an adhesive layer);

[0072] Fig. 15 is a structure diagram of a sensing device with a charge receiving mapping layer provided by the embodiment of the present application (the extension layer is a second adhesive layer);

[0073] Fig. 16 is a structure diagram of a metal wire sewn on a substrate provided by the embodiment of the present application;

[0074] Fig. 17 is a structure diagram of a metal wire adhered to a substrate provided by the embodiment of the present application;

[0075] Fig. 18 is a structure diagram of a sensing device with a charge receiving mapping layer applied to a seat scenario (the substrate is made of a non-conductive material) provided by the embodiment of the present application;

[0076] Fig. 19 is a structure diagram of a sensing device with a charge receiving mapping layer applied to a seat scenario (the substrate is an extension layer) provided by the embodiment of the present application;

[0077] Fig. 20 is a cross-sectional structure diagram of a hand-off detection steering wheel (the extension layer is a substrate) provided by the embodiment of the present application;

[0078] Fig. 21 is a cross-sectional structure diagram of a hand-off detection steering wheel (the extension layer is a skin) provided by the embodiment of the present application;

[0079] Fig. 22 is a cross-sectional structure diagram of a hand-off detection steering wheel (the extension layer is a substrate with a third adhesive layer and a fourth adhesive layer) provided by the embodiment of the present application;

[0080] Fig. 23 is a cross-sectional structure diagram of a hand-off detection steering wheel (the extension layer is an adhesive layer) provided by the embodiment of the present application.

[0081] The text annotations shown in the figure are as follows: 1, automotive interior part; 2, occupancy sensor; 21, sheet-shaped substrate (substrate); 22, metal wire (metallic wire); 3, face cover; 4, capacitor receiving layer (expansion layer); 5, new sensor; 6, wire harness; 31, covering layer; 32, first adhesive layer; 7, skin; 33, third adhesive layer; 34, fourth adhesive layer; 8, adhesive layer; 9, framework; 10, first foaming layer; 11, second foaming layer. DETAILED DESCRIPTION

[0082] The application will be further described below in conjunction with the drawings and examples. It should be understood that the specific examples described herein are merely intended to explain the application, and not to limit the application. In addition, it should be noted that only parts related to the application are shown in the drawings for ease of description.

[0083] It should be noted that the embodiments and features in the embodiments in the application can be combined with each other without conflict. The application will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0084] As mentioned in the background, the application provides a method for detecting the capacitance between an automotive interior part and a human body, as shown in FIG. 1, including the following steps:

[0085] S100. Set an occupancy capacitance threshold, a sampling period and a heating period;

[0086] Optionally, the length of the heating period is 2.5 times or more than the length of the sampling period, for example, the heating period is 200 ms, and the sampling period is 20 ms, totaling 0.22 seconds.

[0087] S200. Heat the automotive interior part 1 by the metal wire 22 in the heating period, wherein the automotive interior part 1 is provided with a human body occupancy sensor 2, the human body occupancy sensor 2 is provided with a sheet-shaped substrate 21 and the metal wire 22 on the sheet-shaped substrate 21;

[0088] Wherein, the automotive interior part 1 can be a car seat or a steering wheel, or other interior parts with heating and occupancy detection functions, and the automotive interior part 1 is further provided with a temperature sensor configured to detect the temperature of the automotive interior part 1.

[0089] S300. Obtain a human body occupancy total capacitance by the human body occupancy sensor 2 in the sampling period, wherein the automotive interior part 1 is further provided with a capacitive receiving layer 4 with conductivity, and the human body occupancy total capacitance is obtained through the induced capacitance between the human body and the metal wire 22, between the human body and the capacitive receiving layer 4, and between the metal wire 22 and the capacitive receiving layer 4; including the following steps:

[0090] S310. Obtaining a total single-sampling capacitance according to a first sensing capacitance, a second sensing capacitance and a third sensing capacitance, wherein the first sensing capacitance is a sensing capacitance between a human body and the metal wire 22, the second sensing capacitance is a sensing capacitance between the human body and the capacitance receiving layer 4, and the third sensing capacitance is a sensing capacitance between the metal wire 22 and the capacitance receiving layer 4; comprising the following steps:

[0091] S311. Obtaining the first sensing capacitance between the human body and the metal wire 22;

[0092] The metal wire 22 is coated with an insulating paint, and an insulating protective layer can be further provided on the outermost layer. The metal wire 22 can be sewn on the sheet-shaped base material 21. Due to the limitation of embroidery technology, the metal wires 22 must maintain a certain spacing, forming a relatively sparse wiring form, as shown in FIG. 7. Due to the existence of the wiring spacing, the effective sensing area is small.

[0093] The sensing area of the occupancy sensor 2 and the human body is S, the thickness of the surface cover 3 of the automotive interior part 1 is d, and the dielectric constant is ε. The sensing capacitance is calculated by the following formula: C = εS / 4πkd ∝ S / d formula (2).

[0094] Obviously, the capacitance C is proportional to the sensing area S. Due to the small surface area of the metal wire 22 and the limitation of the wiring process, the effective sensing area (S) is small, resulting in a sensing capacitance of only picofarad (pF), generally about 50 pF.

[0095] S312. Obtaining the second sensing capacitance between the human body and the capacitance receiving layer 4;

[0096] Optionally, the capacitance receiving layer 4 is arranged on the side of the metal wire 22 away from the sheet-shaped base material 21.

[0097] Optionally, the capacitance receiving layer 4 is arranged on any side of the metal wire 22. The capacitance receiving layer 4 has weak conductivity to receive the charge mapped by the metal wire 1 and expand the sensing area.

[0098] According to the capacitance formula C = εS / 4πkd, the working principle of the capacitance receiving layer 4 is set;

[0099] In the capacitance formula, the meanings of the parameters are as follows: C represents the capacitance of the capacitor, ε represents the dielectric constant of the dielectric, different dielectrics such as air, plastic, ceramic, etc. have different dielectric constants. The dielectric constant of air is close to 1, while some specific ceramic materials can have a larger dielectric constant, S represents the facing area of the two plates of the capacitor, d represents the distance between the two plates of the capacitor, the smaller the distance, the larger the capacitance, and k is the electrostatic force constant, which is about 9.0×10 N·m 2 / C 2 .

[0100] According to the above capacitance formula, since the distance between the metal wire 22 and the capacitor receiving layer 4 is very small, the charge of the metal wire 22 is projected to the capacitor receiving layer 4 with almost no loss. After the capacitor receiving layer 4 is provided, the sensing area S is increased from the original surface area of the metal wire 22 to the surface area of the metal wire 22 plus the surface area of the capacitor receiving layer 4, thereby effectively increasing the sensing capacitance.

[0101] Optionally, an insulating layer can also be provided on the surface of the metal wire 22. The insulating layer insulates the metal wire 22 from other structures and does not leak electricity. In the present embodiment, the insulating layer is coated on the surface of the metal wire 22. Optionally, the insulating layer can be insulating paint applied to the surface of the metal wire 22.

[0102] In addition, although the metal wire 22 is provided with the insulating layer, the insulating layer may be damaged unexpectedly during processing and use. The metal wire 22 may be electrically connected to the capacitor receiving layer 4, causing the damaged metal wire 22 to be electrically connected, which poses a risk of short circuit. Since the capacitor receiving layer 4 is weakly conductive and has a large sheet resistance, even if the insulating layer is damaged, the current between the metal wire 22 at the damaged part will be small, and the heat generated will be small. This can prevent the risk of short circuit when the insulating layer is damaged and the sensing device is burned out.

[0103] Optionally, the metal wire 22 is provided with a sheet-shaped substrate 21 on either side, the sheet-shaped substrate 21 is made of a non-conductive material, and the metal wire 22 is provided with the capacitor receiving layer 4 away from the sheet-shaped substrate 21.

[0104] Optionally, the metal wire 22 is provided with an adhesive layer 8 away from the sheet-shaped substrate 21, the adhesive layer 8 is made of weakly conductive conductive adhesive, and the adhesive layer 8 is the capacitor receiving layer 4. Optionally, the adhesive layer 8 is weakly conductive conductive adhesive. During installation, a release paper coated with weakly conductive conductive adhesive is selected. After the release paper is removed, the weakly conductive conductive adhesive is attached to the side of the metal wire 22 away from the substrate 21.

[0105] Optionally, the metal wire 22 is provided with a first adhesive layer 32 on the side away from the sheet substrate 21, and the first adhesive layer 32 is provided with a cover layer 31 on the side away from the metal wire 22, the cover layer 31 being a flexible sheet made of micro-conductive material, and the cover layer 31 being the capacitor receiving layer 4. Optionally, the flexible sheet of the cover layer 31 is a foam or fabric made of micro-conductive material.

[0106] Optionally, the metal wire 22 is adhered to the sheet substrate 21 by a second adhesive layer, and the second adhesive layer is made of weakly conductive conductive adhesive, and the second adhesive layer being the capacitor receiving layer 4.

[0107] Please refer to FIG. 3, FIG. 4, FIG. 8 and FIG. 12, the capacitor receiving layer 4 can be a metal cloth, a micro-conductive fiber cloth or any high-durability flexible material doped with a micro-conductive component; the capacitor receiving layer 4 and the occupancy sensor 2 are two independent layers, but they are closely attached with a distance of approximately 0. FIG. 12 is an exploded view, and in fact the capacitor receiving layer 4 and the metal wire 22 are closely attached, the metal wire 22 and the control module are connected by a wire harness, and the control module stores a program configured to execute the method for detecting the capacitance between the automotive interior part and the human body according to the embodiments of the present application.

[0108] Optionally, the sheet substrate 21 has weak electrical properties, and the sheet substrate 21 is used as the capacitor receiving layer 4.

[0109] Optionally, the metal wire 22 is provided with a skin 7 on the side away from the sheet substrate 21, and the skin 7 is made of micro-conductive material, and the skin 7 being the capacitor receiving layer 4.

[0110] Optionally, the micro-conductive material is obtained by carburizing, printing, soaking in conductive liquid, electroplating or adding conductive fibers to woven fibers.

[0111] Optionally, the sheet resistance of the capacitor receiving layer 4 is between 10 3 -10 6 Ω.

[0112] Referring to FIG. 5, FIG. 6, FIG. 8 and FIG. 11, the metal wire 22 is directly embroidered on the capacitive buffer layer 4 using the capacitive buffer layer 4 as the sheet substrate 21 of the occupancy sensor 2, so that the capacitive buffer layer 4 and the occupancy sensor 2 are combined into one, called a new sensor 5 with buffer expansion function. The sheet substrate 21 of the new sensor 5 can be a micro-conductive fiber cloth or any high-durability flexible material doped with a micro-conductive component. With the capacitive buffer layer 4 as the sheet substrate 21, the occupancy sensor 2 is in the same layer, and the layer spacing is 0. From the perspective of sensing area, the capacitive buffer layer 4 fills the entire plane space with induced charges, which is equivalent to eliminating the gap between the metal wires 22, thus greatly increasing the sensing area.

[0113] S313. Obtain a third induced capacitance between the metal wire 22 and the capacitive buffer layer 4;

[0114] As shown in FIG. 9 and FIG. 10, C2 represents the second induced capacitance, C3 represents the third induced capacitance, and C1 represents the first induced capacitance. The distance between the capacitive buffer layer 4 and the metal wire 22 is very small and can be ignored, so the charge mapping loss between them is very small. According to formula (2), the induced capacitance is inversely proportional to the distance between them, so the sensing performance of the capacitive buffer layer 4 is guaranteed.

[0115] S314. Input the first induced capacitance, the second induced capacitance and the third induced capacitance into a total capacitance calculation function to obtain a total capacitance;

[0116] Wherein, the equivalent circuit of the embodiment of the application is shown in FIG. 9, and the capacitance calculation function is as follows: C=C1+C2*C3 / (C2+C3) Formula (1)

[0117] Wherein, C represents the total capacitance, C1 represents the first induced capacitance, C2 represents the second induced capacitance, and C3 represents the third induced capacitance.

[0118] Alternatively, the single-sampling total capacitance can be directly obtained without steps S311-S314, or the first induced capacitance, the second induced capacitance and the third induced capacitance can be obtained respectively through steps S311-S314, and then the single-sampling capacitance is obtained by calculation.

[0119] Wherein, the metal wire 22 can be used as a heater in addition to being used as an induction electrode, thus realizing the functions of capacitance detection and traditional heating of the automotive interior part 1.

[0120] S320. Obtain the total capacitance of the human body occupancy through a capacitance average strategy; including the following steps:

[0121] S321. Set the single sampling number;

[0122] S322. Obtain a total capacitance sequence, the total capacitance sequence comprising a plurality of single sampling total capacitances, the number of total capacitances of the total capacitance sequence being the same as the single sampling number;

[0123] Optionally, the single sampling number is 4, and the capacitance sequence is [C1, C2, C3, C4]; wherein C1 represents the single sampling total capacitance obtained by the first sampling, C2 represents the single sampling total capacitance obtained by the second sampling, C3 represents the single sampling total capacitance obtained by the third sampling, and C4 represents the single sampling total capacitance obtained by the fourth sampling.

[0124] S344. Calculate the arithmetic mean of the total capacitance sequence to obtain the total human occupancy capacitance.

[0125] The embodiment of the present application adds the second sensing capacitance and the third sensing capacitance relative to the prior art, the value of the total capacitance obtained by formula (1) is greater than the first sensing capacitance, and preferably, the material of the capacitance receiving layer 4 is a very dense flexible material similar to a metal plate. Compared with the sparse wiring mode of the metal wire 22, the sensing area is much larger than that of the metal wire 22, so the second sensing capacitance is much larger than the first sensing capacitance. In addition, the distance between the capacitance receiving layer 4 and the metal wire 22 is approximately 0, and the third sensing capacitance is much larger than the first sensing capacitance.

[0126] S400. Compare the size of the total human occupancy capacitance and the occupancy capacitance threshold to obtain a comparison result, the comparison result comprising a first comparison result and a second comparison result, the first comparison result representing that the automotive interior part 1 is occupied when the total human occupancy capacitance is greater than or equal to the occupancy capacitance threshold, and the second comparison result representing that the automotive interior part 1 is not occupied when the total human occupancy capacitance is less than the occupancy capacitance threshold;

[0127] S500. Perform step S200; that is, after the capacitance detection, the automotive interior part 1 is heated again;

[0128] S600. Update the total human occupancy capacitance and perform steps S300-S400; comprising the following steps:

[0129] S610. Remove the first single-sampling total capacitance in the total capacitance sequence, and add the single-sampling total capacitance obtained in the next sampling period at the end of the total capacitance sequence to obtain an updated total capacitance sequence, taking the number of single-sampling as 4, the updated total capacitance sequence is [C2, C3, C4, C5]; wherein C5 represents the single-sampling total capacitance obtained in the fifth sampling;

[0130] S620. Calculate the arithmetic mean of the updated total capacitance sequence to obtain the next human body occupancy total capacitance, which is the first occupancy total capacitance;

[0131] S630. Update the human body occupancy total capacitance in step S360 to the first occupancy total capacitance;

[0132] S700. Repeat steps S500-S600; except for the first capacitance detection, each subsequent capacitance detection needs to update the human body occupancy total capacitance before capacitance detection; this application alternately performs capacitance detection and heating functions by time division multiplexing, and increases the inductive capacitance by adding the capacitance receiving layer 4 to improve the sensitivity of detection.

[0133] The metal wire 22 is 5.8 meters, the wiring spacing of the metal wire 22 is 10mm; the capacitance receiving layer 4 is a micro-conductive cloth of 0.7m x 0.4m; the surface cover 3 is made of leather, and its thickness is 4mm. As an example, the test data without the capacitance receiving layer 4 is shown in Table 1, and the test data with the capacitance receiving layer 4 is shown in Table 2:

[0134] Table 2

[0135] From the comparison of Table 1 and Table 2, the scheme of placing the capacitance receiving layer 4 on the metal wire 22 increases the total capacitance by 65% compared to the current scheme, and the scheme of using the sheet substrate 21 as the capacitance receiving layer 4 increases the total capacitance by 73% compared to the current scheme.

[0136] Optionally, the product of the sum of the sampling period and the heating period and the number of single-sampling is less than a preset detection time length, so that the comparison result can be obtained at least once within the preset detection time length.

[0137] Optionally, the preset detection time length can be 1s or 2s, according to the heating period of 200ms and the sampling period of 20ms, the total is 0.22 seconds, then four periods of heating and capacitance detection can be performed within 1s or 2s, and the human body occupancy state can be identified within 1s or 2s.

[0138] Optionally, the capacitor receiving layer 4 has weak conductivity.

[0139] In order to avoid electric leakage, the metal wire 22 is coated with an insulating layer, but during the embroidery process, the embroidery machine or other reasons may damage the insulating layer. At this time, if a capacitor receiving layer 4 with strong conductivity is used, there may be a risk of short circuit, serious heating, and consequences of burning the interior trim part. Using a weakly conductive material, because its resistance is very large, 10 3 Ω to 10 6 Ω, the resistance is large, the current is small, and the heating amount is also small, so the anti-reversibility of the human occupancy sensor is improved, and the risk of product damage is reduced.

[0140] Optionally, the capacitor receiving layer 4 has strong conductivity, and has a strong dielectric layer between the capacitor receiving layer 4 and the metal wire 22.

[0141] When the capacitor receiving layer 4 has strong conductivity, the sensitivity of the occupancy sensor 2 is higher, but if the insulating layer of the metal wire 22 is damaged, it is easy to short circuit with the capacitor receiving layer 4, so the safety is lower. The conductivity of the capacitor receiving layer 4 needs to be selected according to actual needs.

[0142] The above description is only the preferred embodiment of the present application and the explanation of the applied technical principles. Those skilled in the art should understand that the application range involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features can be replaced with the technical features disclosed in the present application (but not limited to) with similar functions to form technical solutions.

[0143] The present application also proposes a sensing device with a charge receiving mapping layer, comprising:

[0144] The functional layer at least includes a metal wire 22 and an insulating layer, and the metal wire 22 is configured to heat and sense. The metal wire 22 mentioned here is equivalent to the metal wire 22 mentioned above.

[0145] Optionally, the insulating layer insulates the metal wire 22 from other structures and does not leak electricity. In the present embodiment, the insulating layer is coated on the surface of the metal wire 22. Optionally, the insulating layer can be insulating paint applied to the surface of the metal wire 22.

[0146] Optionally, please refer to FIG. 13, FIG. 18 and FIG. 19, the functional layer is a cushion layer for the sensor device to function, in the frequency-sharing capacitive detection occupancy technology, the metal wire 22 serves as both a heating element to provide heating function and a sensing element to provide sensing function, when providing sensing function, the sensing sensitivity under this technology is not high due to the small surface area of the metal wire 22, and technical improvement is made on this technology.

[0147] The functional layer is formed by coiling the metal wire 22, and the outer layer of the metal wire 22 has the insulating layer, and the functional layer is a long strip layer structure obtained by coiling the metal wire 22.

[0148] Optionally, the metal wire 22 is connected with a wire harness 6, and the wire harness 6 is configured to be plugged with a control module of the sensor device.

[0149] The extension layer 4 is arranged on any side of the metal wire 22, and the extension layer 8 has weak conductivity to receive the electric charge mapped out by the metal wire 22 and enlarge the sensing area. The extension layer 4 mentioned here is equivalent to the capacitive receiving layer 4 mentioned above.

[0150] According to the capacitive formula C = εS / 4πkd, the working principle of the extension layer 8 is set;

[0151] In the capacitive formula, the meanings of the parameters are as follows: C represents the capacitance of the capacitor, ε represents the dielectric constant of the dielectric, different dielectrics such as air, plastic, ceramic, etc. have different dielectric constants. The dielectric constant of air is close to 1, while some specific ceramic materials may have a larger dielectric constant, S represents the opposite area of the two plates of the capacitor, d represents the distance between the two plates of the capacitor, the smaller the distance, the larger the capacitance, and k is the electrostatic force constant, whose value is about 9.0×10N·m 2 / C 2 .

[0152] According to the above capacitive formula, since the distance between the metal wire 22 and the extension layer 4 is very small, the electric charge of the metal wire 22 is almost lossless when projected to the extension layer 4. After the extension layer 4 is set, the sensing area S is increased from the surface area of the metal wire 1 to the surface area of the metal wire 22 plus the surface area of the extension layer 4, thereby effectively increasing the sensing capacitance.

[0153] In addition, although the metal wire 4 is provided with the insulating layer, the insulating layer can be damaged unintentionally during processing and use, and the metal wire 22 can be electrified with the expansion layer 4, so that the damaged metal wire 22 is electrified, causing a short circuit danger. Since the expansion layer 4 is weakly conductive and has a large sheet resistance, even if the insulating layer is damaged, the current between the metal wires 22 at the damaged part will be small, and the heat generated will be small, which can prevent the short circuit danger when the insulating layer is damaged, and the burning of the sensor device.

[0154] Referring to FIGS. 13 and 19, optionally, the metal wire 22 is provided with a substrate 21 on either side, the substrate 21 is made of a micro-conductive material, and the substrate 21 is the expansion layer 4. The substrate 21 mentioned here is equivalent to the sheet-shaped substrate 21 mentioned above.

[0155] Optionally, the metal wire 22 is provided with a substrate 21 on either side, the substrate is made of a non-conductive material, and the metal wire 22 is provided with the expansion layer 4 away from the substrate 21 side.

[0156] Optionally, referring to FIG. 16, the metal wire 22 can be connected to the substrate 21 by sewing. As shown in FIG. 14, when the metal wire 22 is connected to the substrate 21 by sewing, the metal wire 22 is provided with an adhesive layer 8 away from the substrate 21 side, the adhesive layer 8 is configured to paste the pad body composed of the functional layer and the expansion layer 4 on other layers, the adhesive layer 8 is made of a weakly conductive conductive adhesive, and at this time, the adhesive layer 8 is the expansion layer 4.

[0157] Optionally, the adhesive layer 8 is a weakly conductive conductive adhesive, and during installation, a release paper coated with a weakly conductive conductive adhesive is selected, and after the release paper is removed, the weakly conductive conductive adhesive is pasted away from the substrate 21 side of the metal wire 22.

[0158] Optionally, when the metal wire 22 is connected to the substrate 21 by sewing, in order to solve the problem of uneven appearance of the steering wheel after coating caused by the sewing process of the metal wire 22, a flexible sheet-shaped body which can be soft foam or fabric can be added above the metal wire 22, and the soft foam or fabric, non-woven fabric and the like are made of a micro-conductive material.

[0159] Referring to FIG. 15, optionally, the metal wire 22 is provided with a first adhesive layer 32 without conductivity away from the substrate 21 side, the first adhesive layer 32 is provided with a covering layer 31 away from the metal wire 22 side, and the covering layer 31 is a flexible sheet-shaped body made of a micro-conductive material, and at this time, the covering layer 31 is the expansion layer 4.

[0160] Optionally, the flexible sheet of the covering layer 31 is made of micro-conductive material, and is foamed or woven.

[0161] Optionally, as shown in FIG. 17, the metal wire 22 can also be connected to the base material 21 by adhesive means. Optionally, the metal wire 22 is pasted to the base material 21 by a second adhesive layer, and the second adhesive layer is made of weakly conductive conductive adhesive. In this case, the second adhesive layer is the extension layer 4.

[0162] Optionally, the micro-conductive material is obtained by means of carbonization, printing, soaking in conductive liquid, electroplating, or adding conductive fibers to woven fibers.

[0163] Optionally, the sheet resistance of the extension layer 4 is between 10 3 -10 6 Ω.

[0164] Optionally, the sensing device further comprises a skin 7, which is arranged on the side of the metal wire 22 away from the base material 21, and the skin 7 is made of micro-conductive material, and the skin 7 is the extension layer 4.

[0165] Optionally, each layer in the sensing device proposed in the present application can be used as an extension layer, and the forms of the structures of the layers other than the extension layer can be combined with each other, and are not limited to the above-mentioned several embodiments.

[0166] The present embodiment also proposes a hand-off detection steering wheel, which comprises a steering wheel body, and the surface of the steering wheel body is provided with the sensing device with the charge-accepting mapping layer mentioned above.

[0167] Optionally, the steering wheel body comprises at least a steering wheel skeleton 9 arranged at the innermost side (the side farthest away from the human body gripping side) and a first foamed layer 10 wrapped outside the steering wheel skeleton 9, and the side of the first foamed layer 10 away from the steering wheel skeleton 9 is provided with the sensing device with the charge-accepting mapping layer mentioned above.

[0168] Optionally, as shown in FIG. 20, the extension layer 4 of the hand-off detection steering wheel is the base material 21, and the side of the metal wire 22 away from the body is provided with the base material 21 made of micro-conductive material, and the side of the base material 21 away from the body is provided with a second foamed layer 11, and the second foamed layer 11 can be made by using a secondary foaming process.

[0169] Please refer to the embodiment of the hand-off detection steering wheel shown in Figure 21, the expansion layer 4 of the hand-off detection steering wheel is the skin 7 made of micro-conductive material. At this time, the base material 21 is made of non-conductive material, and the metal wire 22 is coiled on the base material 21 to form the functional layer. The functional layer is provided with a second foaming layer 11 away from the first foaming layer 10 side, and the second foaming layer 11 can be made by using a secondary foaming process.

[0170] Please refer to the hand-off detection steering wheel shown in Figure 22, the expansion layer 4 of the hand-off detection steering wheel is the base material 21, at this time, the first foaming layer 10 is provided with a third adhesive layer 33 made of non-conductive material away from the steering wheel skeleton 9 side, and the third adhesive layer 33 is configured to paste the expansion layer 4 on the body. The third adhesive layer 33 is provided with the base material 21 away from the body side, and the metal wire 22 is coiled on the base material 21. The base material 21 is also provided with a fourth adhesive layer 34 away from the body side, and the fourth adhesive layer 34 is configured to paste the skin 7 on the base material 21.

[0171] Please refer to the hand-off detection steering wheel shown in Figure 23, the expansion layer 4 of the hand-off detection steering wheel is the adhesive layer 8, at this time, the base material 21 is made of non-conductive material, and the base material 21 is pasted and wrapped on the steering wheel body through the third adhesive layer 33. The metal wire 22 is coiled on the base material 21, the base material 21 is provided with the adhesive layer 8 away from the third adhesive layer 33 side, the adhesive layer 8 is configured to paste the skin 7 on the base material 21, and the skin 7 is made of non-conductive material.

[0172] The principles and embodiments of the present application are described herein by using specific examples, and the above examples are only used to help understand the method and core idea of the present application. The above description is only the preferred embodiment of the present application, and it should be pointed out that due to the limitation of language expression, there are infinite specific structures, and for ordinary skilled persons in the technical field, some improvements, decorations or changes can be made without departing from the principles of the present application, and the above technical features can be combined in an appropriate way. The improved, decorated, changed or combined, or the application of the concept and technical solution without improvement to other occasions, should be regarded as the protection scope of the present application. Industrial applicability

[0173] In summary, the embodiment of the present application provides a capacitive detection method between an automotive interior part and a human body, a sensing device with a charge receiving mapping layer, and a hand-off detection steering wheel, which can improve the sensitivity of capacitive detection to improve the accuracy of judgment.

Claims

1. A method of detecting capacitance between an automotive interior member and a human body, characterized by, The method comprises the following steps: S100. Setting an occupancy capacitance threshold, a sampling period and a heating period; S200. Heating the automotive interior part (1) by the metal wire (22) in the heating period, wherein the automotive interior part (1) is provided with a human body occupancy sensor (2), the human body occupancy sensor (2) is provided with a sheet-shaped substrate (21) and the metal wire (22) on the sheet-shaped substrate (21); S300. Obtaining a human body occupancy total capacitance by the human body occupancy sensor (2) in the sampling period, wherein the automotive interior part (1) is further provided with a capacitance receiving layer (4) with electrical conductivity, and the human body occupancy total capacitance is obtained through induced capacitances between a human body and the metal wire (22), between the human body and the capacitance receiving layer (4), and between the metal wire (22) and the capacitance receiving layer (4); S400. Comparing the human body occupancy total capacitance and the occupancy capacitance threshold to obtain a comparison result, wherein the comparison result comprises a first comparison result and a second comparison result, the first comparison result represents that the automotive interior part (1) is occupied, and the second comparison result represents that the automotive interior part (1) is not occupied; S500. Executing step S200; S600. Updating the human body occupancy total capacitance and executing steps S300-S400; S700. Repeating steps S500-S600.

2. The method of claim 1, wherein The step of obtaining the human body occupancy total capacitance by the human body occupancy sensor (2) in the sampling period comprises the following steps: S310. Obtaining a single sampling total capacitance according to a first induced capacitance, a second induced capacitance and a third induced capacitance, wherein the first induced capacitance is the induced capacitance between a human body and the metal wire (22), the second induced capacitance is the induced capacitance between the human body and the capacitance receiving layer (4), and the third induced capacitance is the induced capacitance between the metal wire (22) and the capacitance receiving layer (4); S320. Obtaining the human body occupancy total capacitance through a capacitance mean value strategy.

3. The method of detecting capacitance between an automobile interior member and a human body according to claim 1 or 2, characterized by, The capacitance receiving layer (4) is arranged on a side of the metal wire (22) away from the sheet-shaped substrate (21).

4. The method of detecting capacitance between an automobile interior member and a human body according to claim 1 or 2, characterized by, The sheet-shaped substrate (21) has weak electrical conductivity, and the sheet-shaped substrate (21) is used as the capacitance receiving layer (4).

5. The method of capacitance detection between an automotive interior trim part and a human body according to any one of claims 2 to 4, characterized in that, The capacitance mean value strategy comprises the following steps: S321. Setting a single sampling number; S322. Obtaining a total capacitance sequence, wherein the total capacitance sequence comprises a plurality of single sampling total capacitances, and the number of single sampling total capacitances in the total capacitance sequence is the same as the single sampling number; S323. Taking an arithmetic mean value of the total capacitance sequence to obtain the human body occupancy total capacitance.

6. The method of detecting capacitance between an automobile interior member and a human body according to claim 5, characterized by, The step of updating the human body occupancy total capacitance comprises the following steps: S610. Removing the first single-sampling total capacitance in the total capacitance sequence, and adding the single-sampling total capacitance obtained in the next sampling period at the end of the total capacitance sequence to obtain an updated total capacitance sequence; S620. Calculating the updated total capacitance sequence by an arithmetic mean to obtain a next human body occupancy total capacitance, which is a first occupancy total capacitance; S630. Updating the human body occupancy total capacitance in step S300 to the first occupancy total capacitance.

7. The method of detecting capacitance between an automobile interior member and a human body according to claim 5 or 6, characterized by, The sum of the sampling period and the heating period is less than the product of the preset detection time length and the number of single sampling, so that the comparison result can be obtained at least once within the preset detection time length.

8. The method of capacitance detection between an automotive interior trim part and a human body according to any one of claims 1 to 7, characterized in that, The length of the heating period is 2.5 times or more of the length of the sampling period.

9. The method of claim 1-3, wherein, The capacitance receiving layer (4) has weak conductivity.

10. The method of capacitance detection between an automotive interior component and a human body according to any one of claims 1-3, wherein, The capacitance receiving layer (4) has a strong conductive layer, and a strong dielectric layer is arranged between the strong conductive layer and the metal wire (22).

11. A sensing device with a charge-accepting map layer, characterized by It comprises: A functional layer, which at least comprises a metal wire (22) and an insulating layer, and the metal wire (22) is configured to heat and sense; An extension layer (4) arranged on any side of the metal wire (22), and the extension layer (4) has weak conductivity to receive the electric charge mapped by the metal wire (1) and expand the sensing area.

12. The sensing device with a charge-accepting mapping layer of claim 11, wherein: A substrate (21) is arranged on any side of the metal wire (22), and the substrate (21) is made of micro-conductive material, and the substrate (21) is the extension layer (4).

13. The sensing device with a charge-accepting mapping layer of claim 11, wherein: A substrate (21) is arranged on any side of the metal wire (22), and the substrate (21) is made of non-conductive material, and the metal wire (22) is away from the side of the substrate (21) and is provided with the extension layer (4).

14. The sensing device with a charge-accepting mapping layer of claim 13, wherein: The metal wire (22) is away from the side of the substrate (21) and is provided with the extension layer (4).

15. The sensing device with a charge-accepting mapping layer of claim 13, wherein: The metal wire (22) is away from the side of the substrate (21) and is provided with the first adhesive layer (32), and the first adhesive layer (32) is away from the side of the metal wire (22) and is provided with a covering layer (31), and the covering layer (31) is a flexible sheet made of micro-conductive material, and the covering layer (31) is the extension layer (4).

16. The sensing device with a charge-accepting mapping layer of claim 13, wherein: The metal wire (22) is pasted on the substrate (21) through a second adhesive layer, and the second adhesive layer is made of weak conductive conductive adhesive, and the second adhesive layer is the extension layer (4).

17. The sensing device with a charge-accepting mapping layer according to any one of claims 11-16, characterized in that: The sheet resistance of the extension layer (4) is between 10 3 -10 6 Ω.

18. The sensing device with a charge-accepting mapping layer of claim 11, wherein: The sensing device further comprises a skin (7) arranged on the side of the metal wire (22) away from the substrate (21), and the skin (7) is made of micro-conductive material, and the skin (7) is the extension layer (4).

19. The sensing device with a charge-accepting mapping layer of claim 12 or 15 or 18, wherein: The micro-conductive material is obtained by adding conductive fibers to carbonizing, printing, soaking conductive liquid, electroplating, or woven fibers.

20. A hands-off detection steering wheel, characterized by: The hand-off detection steering wheel comprises a steering wheel body, and a surface of the steering wheel body is provided with the sensing device with the charge receiving mapping layer according to any one of claims 11-19.

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