Steering wheel having hands-off detection function and hands-off detection method for steering wheel

Abstract

A steering wheel (100) having a hands-off detection function and a hands-off detection method for a steering wheel (100). The steering wheel (100) having a hands-off detection function comprises: a frame (10); and a sensing layer (30) wrapped around the frame (10), wherein the sensing layer (30) comprises a first conductive wire (31) and a second conductive wire (32), the first conductive wire (31) and the second conductive wire (32) form a mutual capacitance sensor (202). In a single sensing area, only one first conductive wire (31) and only one second conductive wire (32) are provided, and the first conductive wire (31) and the second conductive wire (32) are bent reciprocatingly on the same layer to form the sensing layer (30).

Description

Steering wheel with hands-off detection function and steering wheel hands-off detection method TECHNICAL FIELD

[0001] The present application relates to the technical field of steering wheel hands-off detection, and particularly relates to a steering wheel with hands-off detection function and a steering wheel hands-off detection method. BACKGROUND

[0002] Hands-off detection (HOD) is a technology for an advanced driver assistance system (ADAS) to configure a hands-off detection device on a steering wheel to monitor whether a driver's hands are on the steering wheel and to identify different types of gestures when the driver grips the steering wheel. The working principle of the hands-off detection device is that the change in the capacitance formed by the sensing layer in the hands-off detection device and the human hand is used to determine the gripping state of the driver relative to the steering wheel.

[0003] In actual application, the ADAS system identifies and determines the state of the driver to switch the driving mode. For example, during the automatic driving mode of the vehicle, if the ADAS system detects that a human hand touches or grips the steering wheel through the hands-off detection device, the ADAS system determines that the driver wants to intervene in the driving operation, and thus the ADAS system switches the driving mode of the vehicle from the automatic driving mode to the manual driving mode.

[0004] The sensing layer in the hands-off detection device can usually be formed by bending a metal wire on a layered surface or by a metal foil. However, the installation process involved in wrapping the metal foil on the steering wheel is relatively complex and can affect the user experience of the steering wheel.

[0005] When the sensing layer is a layered structure formed by bending a metal wire, the sensing layer can include a self-capacitance sensor and a mutual-capacitance sensor. The self-capacitance sensor is coupled to GND and a core bone by one metal wire, and the mutual-capacitance sensor is coupled by two metal wires.

[0006] In related technologies, when the steering wheel uses a self-capacitance sensor, the metal wire forming the sensing layer and the core bone need a shielding layer due to the need to decouple the self-capacitance sensor from GND or the core bone. Therefore, at least two layers of structure are needed to adapt to such self-capacitance measurement. When the steering wheel uses a mutual-capacitance sensor, two metal wires are located on two layers of structure, so at least two layers of structure also need to be configured to adapt to such mutual-capacitance measurement, resulting in an inability to reduce costs.

[0007] In addition, environmental factors have a greater impact on self-capacitance measurement, especially water or metal on the steering wheel has a greater impact on self-capacitance measurement. In addition, different electromagnetic environments have different sensitivities to self-capacitance measurement and mutual-capacitance measurement. It can be seen that when only self-capacitance measurement or mutual-capacitance measurement is performed, the best measurement effect of the off-hand detection device to sense the gesture of the human hand on the steering wheel cannot be obtained.

[0008] In addition, the existing off-hand detection device is too simple in collecting human hand signals. For example, some detection devices can only detect whether the human hand is holding the steering wheel, but cannot detect the position of the human hand holding the steering wheel. Some other off-hand detection devices can detect the position of the human hand holding the steering wheel, but cannot detect the posture of the human hand holding the steering wheel. SUMMARY

[0009] To overcome the problems in the related art, the present disclosure provides a steering wheel with an off-hand detection function and a steering wheel off-hand detection method.

[0010] According to a first aspect of the embodiments of the present disclosure, the present disclosure provides a steering wheel with an off-hand detection function, comprising: a core bone; and a sensing layer wrapped outside the core bone, the sensing layer comprising a first conductive wire and a second conductive wire, the second conductive wire and the first conductive wire forming a mutual-capacitance sensor, wherein in a single sensing area, the first conductive wire is provided with and only one, the second conductive wire is provided with and only one, and the first conductive wire and the second conductive wire are reciprocally bent on the same level to form the sensing layer.

[0011] In some embodiments, the first conductive wire and the second conductive wire extend along the circumferential direction of the steering wheel and are folded back along the transverse direction of the steering wheel.

[0012] In some embodiments, the sensing layer comprises a plurality of the sensing areas, wherein each of the sensing areas comprises one of the first conductive wires and one of the second conductive wires.

[0013] In some embodiments, the first conductive wire or the second conductive wire alone serves as a self-capacitance sensor.

[0014] In some embodiments, the switching between the self-capacitance sensor and the mutual-capacitance sensor is through a time-division multiplexing control method.

[0015] In some embodiments, the first conductive wire and the second conductive wire are made of metal wires or gold-plated metal wires.

[0016] In some embodiments, the steering wheel further comprises an outer cover wrapped outside the sensing layer and a buffer layer located between the core bone and the sensing layer and / or between the sensing layer and the outer cover.

[0017] In some embodiments, the steering wheel can further include a heating pad between the sensing layer and the cushioning layer.

[0018] According to a second aspect of the embodiments of the present disclosure, the present disclosure provides a steering wheel off-hand detection method, comprising: step one, mutual capacitance sensor measurement; step two, obtaining an initial capacitance value of an empty steering wheel and a measured capacitance value of the steering wheel after being processed by a filter; and step three, distinguishing different gesture states on the steering wheel based on changes in the measured capacitance value and the initial capacitance value.

[0019] In some embodiments, the step one further comprises self-capacitance sensor measurement, wherein the self-capacitance sensor measurement and the mutual capacitance sensor measurement are alternately performed by time division multiplexing.

[0020] In some embodiments, when the self-capacitance sensor measurement is performed, the step two further comprises: obtaining a capacitance fluctuation of the self-capacitance sensor to adjust the strength of the filter; and obtaining a capacitance change rate of the self-capacitance sensor to compensate for the initial capacitance value.

[0021] In some embodiments, when the self-capacitance sensor measurement is performed, the step three further comprises: assisting in identifying different types of gestures based on self-capacitance changes of the self-capacitance sensor.

[0022] The technical solutions provided by the embodiments of the present disclosure can have the following beneficial effects: the mutual capacitance sensor formed by the first conductive wire and the second conductive wire is located in the same layer, and each of the first conductive wire and the second conductive wire has only one wire on the sensing layer. Not only is the sensing layer structure simple and low in cost, but also the effective expansion area is large, and the sensitivity of sensing a human hand holding the steering wheel is high. BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present disclosure and, together with the specification, serve to explain the principles of the present disclosure.

[0024] FIG. 1 is a cross-sectional view of a steering wheel according to an exemplary embodiment;

[0025] FIG. 2 is a structural schematic diagram of a sensing layer connected with a vehicle-mounted controller according to an exemplary embodiment;

[0026] FIG. 3 is a structural schematic diagram of bending of a first metal wire and a second metal wire in a single sensing area according to an exemplary embodiment;

[0027] FIG. 4 is a schematic diagram when alternately controlled by time division multiplexing;

[0028] FIG. 5 is a flowchart of a method of steering wheel hands-off detection, according to an example embodiment. DETAILED DESCRIPTION

[0029] The example embodiments will be described in detail herein with reference to the attached drawings. In the following description, like reference numerals refer to like elements, unless the context clearly dictates otherwise. The implementations described in the following example embodiments are not meant to represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0030] To solve the above technical problems, the present disclosure provides a steering wheel 100 with hands-off detection function, as shown in FIG. 1, the steering wheel 100 comprises a core bone 10, a buffer layer 20, a sensing layer 30 and an outer sleeve 40. Wherein, the buffer layer 20 is wrapped outside the core bone 10, the sensing layer 30 is wrapped outside the buffer layer 20, and the outer sleeve 40 is wrapped outside the sensing layer 30. The outer wall of the outer sleeve 40 is used for the driver's hand to touch.

[0031] Wherein, the core bone 10 of the steering wheel 100 is a rigid structure, usually in the shape of a cylinder, and the core bone 10 can be made of magnesium or aluminum material. The rigid property of the core bone 10 can provide the steering wheel 100 with basic shape and support, that is, the core bone 10 fixes the basic shape of the steering wheel 100, and provides the strength required for the driver to grip or rotate the steering wheel 100. The buffer layer 20 is arranged around the core bone 10, and the buffer layer 20 can also be in the shape of a cylinder. The buffer layer 20 is made of a compressible material with memory, for example, the buffer layer 20 is usually made of polyurethane or foam material, so as to allow the steering wheel 100 to have a buffering function, so that the driver can hold the steering wheel 100 more comfortably and softly, and improve the hand feeling of the driver holding the steering wheel 100.

[0032] As shown in FIG. 2, the sensing layer 30 comprises a first conductive wire 31 and a second conductive wire 32, and the first conductive wire 31 and the second conductive wire 32 are reciprocally bent on the same level to form the sensing layer 30. That is, the first conductive wire 31 and the second conductive wire 32 are not spaced in the radial direction. The radial direction refers to the direction of the core bone 10 towards the outer sleeve 40 in FIG. 1. When the sensing layer 30 is wrapped outside the core bone 10, the sensing layer 30 is also in the shape of a cylinder, so the same level refers to the level of the cylinder.

[0033] Wherein, the first conductive wire 31 and the second conductive wire 32 can be made of metal wire or gold-plated metal wire.

[0034] Using metal conductors (such as copper or iron) as the base material for the first conductive wire 31 and the second conductive wire 32 has the advantages of metals having good conductivity, ensuring efficient current transmission, reducing energy loss, and relatively low cost, which is conducive to large-scale production and application. Metal conductors also have high mechanical strength, can withstand certain tensile forces and deformations, and are suitable for use in various environments.

[0035] Adding a gold plating layer to the metal conductor further enhances its performance. The gold plating layer is resistant to oxidation, effectively preventing oxidation and corrosion of the underlying metal conductor, thus extending its lifespan, especially in humid environments. Simultaneously, the gold-plated metal conductor reduces signal attenuation and improves signal transmission purity, which is crucial for high-precision communication and data transmission systems. Therefore, the use of metal conductors and their gold plating leverages the cost-effectiveness and basic conductivity of metal materials while enhancing the durability and stability of the conductive wire through gold plating.

[0036] In some embodiments, the sensing layer 30 may consist only of the first conductive wire 31 and the second conductive wire 32, with the sensing layer 30 thus located between the outer jacket 40 and the buffer layer 20. In other embodiments, the sensing layer 30 may also be covered with a base material, i.e., the base material is located between the outer jacket 40 and the buffer layer 20. The base material can serve as a carrier for bending the first conductive wire 31 and the second conductive wire 32. For example, the first conductive wire 31 and the second conductive wire 32 are attached to the side of the base material away from the core 10. For example, the first conductive wire 31 and the second conductive wire 32 can be sewn onto the base material, or they can be glued to the base material with adhesive, or the first conductive wire 31 and the second conductive wire 32 can be inserted inside the base material. In this way, not only can the first conductive wire 31 and the second conductive wire 32 be protected, but the position of the first conductive wire 31 or the second conductive wire 32 can also be fixed, preventing radial bending after bending. The base material can be made of insulating material, and the first conductive wire 31 and the second conductive wire 32 can also be glued and fixed to the base material with double-sided adhesive.

[0037] Furthermore, either the first conductive wire 31 or the second conductive wire 32 can serve as a self-capacitance sensor 201 on its own; that is, either the first conductive wire 31 or the second conductive wire 32 forms a self-capacitance sensor 201 with GND. The second conductive wire 32 and the first conductive wire 31 form a mutual capacitance sensor 202. In this embodiment, as shown in Figures 2 and 3, the first conductive wire 31 can form the self-capacitance sensor 201.

[0038] It is further understood that the terms "first," "second," etc., are used to describe various structures, but these structures should not be limited to these terms. These terms are only used to distinguish structures of the same type from one another and do not indicate a specific order or degree of importance. In fact, the expressions "first," "second," etc., are completely interchangeable. For example, without departing from the scope of this disclosure, the first conductive wire 31 can also be referred to as the second conductive wire 32, and similarly, the second conductive wire 32 can also be referred to as the first conductive wire 31.

[0039] Furthermore, within a single sensing area, as shown in Figure 2, there is one and only one first conductive wire 31 and one and only one second conductive wire 32. Specifically, only one first conductive wire 31 and one second conductive wire 32 are provided, which can reduce the cost of materials. When the first conductive wire 31 and the second conductive wire 32 form the sensing layer 30, they only need to be continuously bent within a single area, which not only simplifies the structure but also simplifies the manufacturing process and reduces costs.

[0040] In addition, only one first conductive wire 31 and one second conductive wire 32 are set in a single sensing area, so that the effective area of ​​the sensing area is larger and the sensitivity of sensing human hand gripping the steering wheel is high.

[0041] Furthermore, the steering wheel 100 may have only one sensing area, which is laid out along the circumference of the steering wheel 100. The steering wheel 100 may also include multiple sensing areas. For example, the steering wheel 100 may include two sensing areas. In the first case, one of the two sensing areas is a front sensing area facing the driver, and the other is a rear sensing area away from the driver, effectively dividing the steering wheel 100 in two along the front-rear direction. In the second case, one of the two sensing areas is a left-side sensing area, and the other is a right-side sensing area, effectively dividing the steering wheel 100 in two along the left-right direction.

[0042] In the first scenario, the rear sensing area away from the driver can be composed of two smaller sensing areas, which can be arranged along the driver's left-right direction. Furthermore, in the first scenario, the driver-facing sensing area can also be divided into two smaller sensing areas, left and right. The above-described distribution of the sensing areas in the steering wheel 100 is merely exemplary and not intended to limit the scope of protection of this disclosure.

[0043] It should be noted that the sensing area often extends along the circumference of the steering wheel 100 and the area of ​​the sensing area is also relatively large. It is not advisable to set a small sensing area on the steering wheel 100. For example, the number of sensing areas on the steering wheel 100 is 2 to 4.

[0044] It is known that within a single sensing area, there is one and only one first conductive wire 31 and one and only one second conductive wire 32. The first conductive wire 31 and the second conductive wire 32 are located on the same layer and cover the same area. The large area of ​​the conductive wire increases the effective detection area, allowing the single sensing area to detect whether the driver is gripping the steering wheel 100 regardless of where the touch occurs. The sensitivity of the sensor for sensing the driver's grip on the steering wheel 100 is high, and it also allows the ECU measurement and processing module 200 to better determine the driver's grip posture.

[0045] In some embodiments, as shown in FIG3, the first conductive wire 31 and the second conductive wire 32 extend along the circumferential direction of the steering wheel 100 and fold back along the lateral direction of the steering wheel 100. Specifically, in a single region, the first conductive wire 31 and the second conductive wire 32 mainly extend along the circumferential direction of the steering wheel 100, that is, along the length direction of the steering wheel 100, and fold back along the lateral direction of the steering wheel 100 at the end of the single region.

[0046] The first conductive wire 31 and the second conductive wire 32 can be alternated to form a microcapacitive sensor in a local area within a single region. This sensor can also be used to detect whether the driver is gripping the steering wheel 100, thereby improving the sensitivity of the hands-off detection function.

[0047] The first conductive wire 31 and the second conductive wire 32 extend along the length of the steering wheel 100. When the hand grips the steering wheel 100, the number of conductive wires that the four fingers cross laterally is greater, which can cause more micro-capacitance sensors 202 to generate more capacitance changes, thereby further improving the sensitivity of off-hand detection.

[0048] Furthermore, as shown in Figure 5, the switching between the self-capacitance sensor 201 and the mutual capacitance sensor 202 is achieved through a time-division multiplexing control method. The horizontal axis in Figure 4 represents time. By employing time-division multiplexing, the self-capacitance measurement of the self-capacitance sensor 201 and the mutual capacitance measurement of the mutual capacitance sensor 202 are alternately set. This allows off-hand detection to leverage the advantages of both the self-capacitance sensor 201 and the mutual capacitance sensor 202, while using the mutual capacitance sensor 202 as the primary detection method, the self-capacitance sensor 201 can function as the mutual capacitance sensor 202.

[0049] As shown in the figure, the buffer layer 20 can be located between the core 10 and the sensing layer 30. In some embodiments, the buffer layer 20 can also be located between the sensing layer 30 and the outer sleeve 40, that is, the sensing layer 30 is provided on both the inner and outer sides of the sensing layer 30, thereby further improving the feel of the driver gripping the steering wheel 100.

[0050] Furthermore, the steering wheel 100 may also include a heating pad (not shown), which in some embodiments may be located between the sensing layer 30 and the buffer layer 20. The heating layer includes a layer of heating wires, which enables the steering wheel 100 to have a heating function.

[0051] Based on the same inventive concept, this disclosure also provides a method for detecting when a steering wheel 100 is removed from its hands, which is applied to the aforementioned steering wheel 100 with a hands-removal detection function.

[0052] As shown in Figure 5, the method includes the following steps: Step 1, performing mutual capacitance measurement; Step 2, obtaining the initial capacitance value of the empty steering wheel and the measured capacitance value of the steering wheel after being processed by a filter; Step 3, determining whether there is a gesture on the steering wheel 100 based on the changes in the measured capacitance value and the initial capacitance value.

[0053] In step three, the absolute value of the difference between the measured capacitance value and the initial capacitance value can be used. The ECU determines whether the driver is in contact with the steering wheel 100 based on the magnitude of the absolute value.

[0054] In addition, the initial capacitance value of the empty steering wheel refers to the initial capacitance value measured by the mutual capacitance sensor when the driver's hands are not touching the steering wheel.

[0055] In some embodiments, step one further includes self-capacitance measurement, wherein self-capacitance measurement and mutual capacitance measurement are performed alternately using the time-division multiplexing method shown in FIG5. The time-division multiplexing method allows for alternating self-capacitance detection and mutual capacitance detection under the control of the ECU's control module 200. This not only leverages the advantages of both self-capacitance detection and mutual capacitance detection but also allows the capacitance change of self-capacitance to calibrate the accuracy of mutual capacitance detection, thereby improving the performance of the steering wheel 100's hands-off detection.

[0056] In some embodiments, when measuring the self-capacitance sensor 201, step two further includes: acquiring the capacitance fluctuation of the self-capacitance sensor 201 to adjust the strength of the filter; and acquiring the capacitance change rate of the self-capacitance sensor 201 to compensate for the initial capacitance value.

[0057] The capacitance fluctuation of the self-capacitance sensor 201 may be caused by electromagnetic compatibility (EMC). The capacitance change rate of the self-capacitance sensor 201 may be caused by changes in temperature or humidity. By adjusting the filter strength and the initial capacitance value, and correcting the filter strength and the initial value of the mutual capacitance sensor 202, the final measured capacitance value obtained by the mutual capacitance sensor 202 is more accurate, thus improving the sensitivity of the human hand gripping the steering wheel 100.

[0058] In some embodiments, when the self-capacitance sensor 201 is measuring, step three further includes: based on the change in self-capacitance of the self-capacitance sensor 201, assisting in the identification or judgment of different types of gestures. When the mutual capacitance sensor 202 detects a hand gripping the steering wheel 100, the change in self-capacitance of the self-capacitance sensor 201 can further determine the specific abnormal gesture of the hand on the steering wheel 100. For example, sometimes the driver may accidentally touch the steering wheel 100, or the driver may be sleeping on the steering wheel 100. This can alert the ADAS system, thereby enabling the ADAS system to make different responses and ensure the driver's driving safety.

[0059] It is understood that in this disclosure, "multiple" refers to two or more, and other quantifiers are similar. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. The singular forms "a," "the," and "the" are also intended to include the plural forms unless the context clearly indicates otherwise.

[0060] It is further understood that the terms “center,” “longitudinal,” “lateral,” “front,” “rear,” “up,” “down,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation.

[0061] It can be further understood that, unless otherwise specified, "connection" includes both direct connections where no other components exist between the two parties and indirect connections where other components exist between them.

[0062] It is further understood that although operations are described in a specific order in the accompanying drawings in the embodiments of this disclosure, this should not be construed as requiring these operations to be performed in the specific order or serial order shown, or requiring all of the shown operations to be performed to obtain the desired result. In certain environments, multitasking and parallel processing may be advantageous.

[0063] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the following scope of claims.

[0064] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A steering wheel with hands-off detection function, characterized in that, include: Core; A sensing layer, wrapped around the outside of the core, includes a first conductive wire and a second conductive wire, the second conductive wire and the first conductive wire forming a mutual capacitance sensor. Within a single sensing area, there is one and only one first conductive wire and one and only one second conductive wire, and the first and second conductive wires are repeatedly bent on the same layer to form the sensing layer.

2. The steering wheel with hands-off detection function according to claim 1, characterized in that, The first conductive wire and the second conductive wire extend along the circumferential direction of the steering wheel and fold back along the lateral direction of the steering wheel.

3. The steering wheel with hands-off detection function according to claim 1, characterized in that, The sensing layer includes a plurality of sensing regions, wherein each sensing region includes a first conductive wire and a second conductive wire.

4. The steering wheel with hands-off detection function according to claim 1, characterized in that, The first conductive wire or the second conductive wire can be used alone as a self-capacitance sensor.

5. The steering wheel with hands-off detection function according to claim 4, characterized in that, The switching between the self-capacitance sensor and the mutual capacitance sensor is achieved through a time-division multiplexing control method.

6. The steering wheel with hands-off detection function according to claim 1, characterized in that, The first conductive wire and the second conductive wire are made of metal wire or gold-plated metal wire.

7. The steering wheel with hands-off detection function according to claim 1, characterized in that, The steering wheel also includes an outer cover and a buffer layer, the outer cover being wrapped around the outside of the sensing layer, and the buffer layer being located between the core and the sensing layer, and / or between the sensing layer and the outer cover.

8. The steering wheel with hands-off detection function according to claim 7, characterized in that, The steering wheel may also include a heating pad located between the sensing layer and the buffer layer.

9. A method for detecting when a steering wheel is removed from the hands, characterized in that, Includes the following steps: Step 1: Perform mutual capacitance sensor measurement; Step 2: Obtain the initial capacitance value of the empty steering wheel and the measured capacitance value of the steering wheel after processing by the filter; Step 3: Based on the changes in the measured capacitance value and the initial capacitance value, distinguish different hand gesture states on the steering wheel.

10. The method for detecting steering wheel removal from hands according to claim 9, characterized in that, Step one further includes self-capacitance sensor measurement, wherein the self-capacitance sensor measurement and the mutual capacitance sensor measurement are performed alternately by time-division multiplexing.

11. The method for detecting steering wheel removal from hands according to claim 10, characterized in that, When performing self-capacitance sensor measurements, step two further includes: Capacitance fluctuations from a capacitance sensor are acquired to adjust the strength of the filter; and The capacitance change rate from the capacitance sensor is obtained to compensate for the initial capacitance value.

12. The steering wheel removal detection method according to claim 11, characterized in that, When performing self-capacitance sensor measurements, step three also includes: Based on the changes in self-capacitance of the self-capacitance sensor, different types of gestures can be identified.

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