Hand-leaving detection method and controller

Abstract

The embodiment of the invention provides a hand leaving detection method and a controller. The hand-leaving detection method comprises the steps of obtaining a capacitance real-time value of a steering wheel in a current response period, then determining a capacitance variation according to the capacitance real-time value, if the capacitance variation is greater than or equal to a first preset threshold value, keeping a target empty wheel baseline value as an initial empty wheel baseline value, and if the capacitance variation is smaller than the first preset threshold value, keeping the target empty wheel baseline value as an initial empty wheel baseline value. If yes, determining a first accumulated duration when the capacitance variation is kept smaller than a first preset threshold value, when the first accumulated duration is larger than the first preset threshold value, determining a target empty wheel base line value according to the capacitance variation and the initial empty wheel base line value, and finally determining the state of the steering wheel in the current response period according to the capacitance real-time value and the target empty wheel base line value. According to the method, the error influence of holding or touching the steering wheel by a hand on temperature compensation can be reduced, temperature compensation can be performed on the empty wheel base line value more accurately, and the state of the steering wheel can be detected more accurately.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of assisted driving technology, and more particularly to a hands-off detection method and controller. Background Art

[0002] With the development trend of automobile intelligence, the Hands Off Detection (HOD) system in the Advanced Driving Assistance System (ADAS) is a detection system that detects whether the driver's hands are holding the steering wheel. The system is mainly used in the driving process of the vehicle to ensure driving safety.

[0003] The current hands-off detection method used by the HOD system is the capacitive detection method, which identifies the current driver's hands-off state by measuring the capacitance value of the steering wheel. However, the capacitance value detected by the capacitive detection method is easily affected by temperature, so temperature compensation is required in hands-off detection. The capacitance value change caused by temperature is easily confused with the capacitance value change caused by the human hand holding or touching the steering wheel. If no distinction is made and temperature compensation is performed directly, compensation errors will occur, which will lead to inaccurate hands-off detection. Summary of the invention

[0004] The embodiments of the present application aim to provide a hands-off detection method and a controller, which can accurately detect the state of the steering wheel.

[0005] To solve the above technical problems, the present application provides the following technical solutions:

[0006] In a first aspect, an embodiment of the present application provides a hand-off detection method, the method comprising:

[0007] Get the real-time capacitance value of the steering wheel in the current response cycle;

[0008] Determine the capacitance change according to the real-time capacitance value;

[0009] If the capacitance change is greater than or equal to a first preset threshold, the target empty disk baseline value is maintained as an initial empty disk baseline value, wherein the initial empty disk baseline value is an empty disk baseline value of a previous response cycle, and the empty disk baseline value is a capacitance value of the steering wheel collected when no finger is placed on the steering wheel;

[0010] If the capacitance change is less than the first preset threshold, determining a first accumulated time length during which the capacitance change remains less than the first preset threshold;

[0011] When the first accumulated time length is greater than a first preset time length, determining the target empty disk baseline value according to the capacitance change and the initial empty disk baseline value;

[0012] The state of the steering wheel in the current response cycle is determined according to the real-time capacitance value and the target empty wheel baseline value, wherein the state of the steering wheel includes Hands On and Hands Off.

[0013] In some embodiments, before maintaining the target empty disk baseline value as the initial empty disk baseline value, the method further comprises:

[0014] Determining whether the capacitance change is less than a second preset threshold;

[0015] If yes, determining a second accumulated time duration during which the capacitance change remains less than the second preset threshold value, and when the second accumulated time duration is greater than the second preset time duration, determining the target empty disk baseline value according to the capacitance change and the initial empty disk baseline value, wherein the first preset time duration is less than the second preset time duration;

[0016] If not, the target empty disk baseline value is maintained as the initial empty disk baseline value.

[0017] In some embodiments, before maintaining the target empty disk baseline value as the initial empty disk baseline value, the method further comprises:

[0018] Determining whether the capacitance change is less than a third preset threshold;

[0019] If yes, determining a third accumulated time length during which the capacitance change remains less than the third preset threshold value, and when the third accumulated time length is greater than the third preset time length, determining the target empty disk baseline value according to the capacitance change and the initial empty disk baseline value, wherein the second preset time length is less than the third preset time length;

[0020] If not, the target empty disk baseline value is maintained as the initial empty disk baseline value.

[0021] In some embodiments, determining the target empty disk baseline value according to the capacitance change and the initial empty disk baseline value comprises:

[0022] The sum or difference between the initial empty disk baseline value and the capacitance variation is determined as the target empty disk baseline value.

[0023] In some embodiments, determining the state of the steering wheel in the current response cycle according to the real-time capacitance value and the target empty wheel baseline value includes:

[0024] Acquire a first difference between the real-time capacitance value and the target empty disk baseline value;

[0025] If the first difference is greater than a fourth preset threshold, determining that the state of the steering wheel in the current response cycle is Hands On;

[0026] If the first difference is less than or equal to the fourth preset threshold, it is determined that the state of the steering wheel in the current response cycle is Hands Off.

[0027] In some embodiments, obtaining the real-time value of capacitance in the current response cycle includes:

[0028] Acquire a first capacitance value collected by a sensing channel of a capacitance sensor, wherein the first capacitance value is a capacitance value of an actual steering wheel;

[0029] Acquire a second capacitance value collected by a reference channel of the capacitance sensor, wherein the second capacitance value is a capacitance value of a simulated steering wheel;

[0030] A second difference between the first capacitance value and the second capacitance value is determined as the capacitance real-time value.

[0031] In some embodiments, determining the capacitance change according to the real-time capacitance value includes:

[0032] Acquire a third difference, wherein the third difference is a difference between the real-time value of the capacitance in a current response cycle and the real-time value of the capacitance in a previous response cycle;

[0033] The third difference is determined as the capacitance variation.

[0034] In a second aspect, an embodiment of the present application provides a controller, the controller comprising:

[0035] at least one processor; and

[0036] a memory communicatively connected to the at least one processor; wherein,

[0037] The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can perform the hand-off detection method as described above.

[0038] The beneficial effect of the present invention is as follows: compared with the prior art, the embodiment of the present application provides a hands-off detection method, which first obtains the real-time value of the capacitance of the steering wheel in the current response cycle, and then determines the capacitance change according to the real-time value of the capacitance; if the capacitance change is greater than or equal to a first preset threshold, the target empty disk baseline value is maintained as the initial empty disk baseline value; if the capacitance change is less than the first preset threshold, a first accumulated time length for the capacitance change to remain less than the first preset threshold is determined; when the first accumulated time length is greater than the first preset threshold, the target empty disk baseline value is determined according to the capacitance change and the initial empty disk baseline value; finally, the state of the steering wheel in the current response cycle is determined according to the real-time value of the capacitance and the target empty disk baseline value.

[0039] Therefore, the hands-off detection method performs temperature compensation on the empty-disk baseline value so that the empty-disk baseline value can change with the change in temperature, and uses a first preset threshold and a first accumulated time length to distinguish whether the change in capacitance is caused by a person holding or touching the steering wheel or a change caused by temperature, so as to reduce the error influence of the human hand on the temperature compensation, perform temperature compensation on the empty-disk baseline value more accurately, and thus be able to more accurately detect the state of the steering wheel. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0041] Figure 1 A schematic diagram of the structure of a HOD system provided in an embodiment of the present application;

[0042] Figure 2 A schematic diagram of the hardware structure of one of the controllers provided in the embodiments of the present application;

[0043] Figure 3 A flowchart of one of the hand-off detection methods provided in an embodiment of the present application;

[0044] Figure 4 for Figure 3 Flow chart of step S31 in FIG.

[0045] Figure 5 A flowchart of one of the hand-off detection methods provided in an embodiment of the present application;

[0046] Figure 6 A flowchart of one of the hand-off detection methods provided in an embodiment of the present application;

[0047] Figure 7 for Figure 3 Flow chart of step S36;

[0048] Figure 8 A schematic diagram of the structure of a hands-off detection device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0049] In order to facilitate the understanding of the present application, the present application is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "connected" to another element, it can be directly connected to the other element, or there can be one or more intermediate elements therebetween. In addition, the terms "first", "second", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0050] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more of the related listed items.

[0051] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0052] See also Figure 1 , Figure 1 is a schematic diagram of the structure of a HOD system provided in an embodiment of the present application, such as Figure 1 As shown, the HOD (Hands Off Detection, HOD for short) system 100 includes a steering wheel 11, a capacitive sensor 12 and a controller 13. The capacitive sensor 12 and the controller 13 can be packaged on the same PCB board, and the PCB board is arranged on the steering wheel 11. The steering wheel 11, the capacitive sensor 12 and the controller 13 are communicatively connected. The HOD system 100 is a driving assistance system for detecting whether the driver holds the steering wheel with his hands.

[0053] When the human hand does not hold the steering wheel 11, the capacitance value of the steering wheel collected by the capacitance sensor 12 is the empty wheel baseline value. Since the capacitance value collected by the capacitance sensor 12 when the human hand holds the steering wheel is different from the empty wheel baseline value, the capacitance sensor 12 can be used to detect the capacitance value of the steering wheel, and the collected multiple capacitance values ​​are transmitted to the controller 13, and the controller 13 processes and analyzes the multiple capacitance values, and detects the state of the steering wheel 11 through the change of the capacitance value. Among them, the state of the steering wheel 11 includes Hands On and Hands Off, and Hands On means that the human hand holds the steering wheel, and conversely, Hands Off means that the human hand does not hold the steering wheel.

[0054] In some embodiments, the sensor 11 may perform IQ (In-phase Quadrature) modulation processing on the collected capacitance value to obtain an IQ capacitance value, and then transmit the IQ capacitance value to the controller 13, and the controller 13 processes and analyzes the capacitance IQ value to obtain the state of the steering wheel 11. In some embodiments, the controller 13 may directly process and analyze the capacitance value to obtain the state of the steering wheel 11.

[0055] In some embodiments, the controller 13 can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a single-chip microcomputer, an ARM (Acorn RISC Machine) or other programmable logic device, a discrete gate or transistor logic, a discrete hardware component, or any combination of these components. In addition, the controller 13 can also be any conventional processor, controller, microcontroller or state machine. The controller 13 can also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a DSP, and / or any other such configuration.

[0056] Please also read Figure 2 The controller 13 includes at least one processor 131 (connected via a system bus or other communication methods) Figure 2 The controller 13 may be in the form of a chip.

[0057] Among them, the memory 132 stores instructions that can be executed by the at least one processor 131, and the instructions are executed by the at least one processor 131. The processor 131 is used to provide computing and control capabilities to process test data, for example, to execute any one of the hand-off detection methods provided in the following embodiments of the present invention.

[0058] The memory 132, as a non-transient computer-readable storage medium, can be used to store non-transient software programs, non-transient computer executable programs and modules, such as the program instructions / modules corresponding to the hand-off detection method provided in the following embodiments of the present invention. The processor 131 can implement the hand-off detection method in any of the following method embodiments by running the non-transient software programs, instructions and modules stored in the memory 132. Specifically, the memory 132 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some embodiments, the memory 132 may also include a memory remotely arranged relative to the processor 131, and these remote memories may be connected to the processor 131 via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network and a combination thereof.

[0059] Ambient temperature, sweaty palms, adding a leather cover to the steering wheel, etc. may cause the steering wheel temperature to change, and the temperature change will cause the empty disk baseline value to change. If a fixed empty disk baseline value is still used in hands-off detection, it will lead to inaccurate hands-off detection. Therefore, it is necessary to perform temperature compensation on the empty disk baseline value. The change in capacitance value caused by temperature is easily confused with the change in capacitance value caused by holding or touching the steering wheel. If no distinction is made and the empty disk baseline value is directly compensated, it will cause compensation errors, which will lead to inaccurate hands-off detection.

[0060] Based on the above reasons, an embodiment of the present application provides a hands-off detection method, which changes the empty plate baseline value as the temperature changes, reduces the error influence of human hands on temperature compensation, and more accurately performs temperature compensation on the empty plate baseline value, thereby making hands-off detection more accurate.

[0061] See also Figure 3 , Figure 3 is a flow chart of a method for detecting a hand leaving the hand provided in an embodiment of the present application, such as Figure 3 As shown, the hand-off detection method S300 includes:

[0062] S31, obtaining the real-time capacitance value of the steering wheel in the current response cycle;

[0063] In the power-on phase, when there is no hand on the steering wheel, a sensor is used to collect the capacitance value of the steering wheel, and the collected capacitance value is filtered to obtain the empty disk baseline value at the power-on time. In some embodiments, after filtering the collected capacitance value of the steering wheel, it is also possible to determine whether the steering wheel state is stable. After the steering wheel state is stable, the filtered capacitance value is used as the empty disk baseline value at the power-on time. If the steering wheel state is unstable, continue the step of collecting the capacitance value of the steering wheel.

[0064] In some embodiments, a capacitive sensor may be used to directly collect the capacitance of the actual steering wheel. The capacitance value collected in real time is the real-time capacitance value, and the capacitance change amount is subsequently determined based on the real-time capacitance value.

[0065] In some embodiments, a differential signal may also be used as the real-time value of the capacitance to reduce environmental interference and improve anti-interference capability. Figure 4 As shown, step S31 includes:

[0066] S311, obtaining a first capacitance value collected by a sensing channel of a capacitance sensor, wherein the first capacitance value is a capacitance value of an actual steering wheel;

[0067] S312, obtaining a second capacitance value collected by a reference channel of the capacitance sensor, wherein the second capacitance value is a capacitance value of a simulated steering wheel;

[0068] S313: Determine a second difference between the first capacitance value and the second capacitance value as the real-time capacitance value.

[0069] An analog capacitor is used to simulate the capacitance of a steering wheel, and the analog capacitor is set on a PCB board. During detection, the sensing channel of the capacitance sensor is used to collect the capacitance of the actual steering wheel to obtain a first capacitance value, and the reference channel of the capacitance sensor is used to collect the analog capacitance on the PCB board to obtain a second capacitance value. Finally, a second difference between the first capacitance value and the second capacitance value is determined as the real-time capacitance value.

[0070] The capacitance of the actual steering wheel will change with the change of temperature. If only the capacitance of the actual steering wheel is used as the real-time value, the real-time value may fluctuate greatly, the value to be compensated will also be large, and it is easy to be interfered by the environment. In the embodiment of the present application, the differential signal of the first capacitance value and the second capacitance value is used as the real-time value of the capacitance, wherein the first capacitance value will change with the change of temperature, and the second capacitance value will also change with the change of temperature. In an ideal case, the changes of the two are the same, but because the simulated capacitance cannot completely simulate the capacitance of the actual steering wheel, there will be a second difference, but the fluctuation of the second difference will not fluctuate greatly with the change of temperature. Therefore, the second difference is used as the real-time value of the capacitance, the compensation value of the temperature is reduced, and the anti-interference ability of the environment is improved.

[0071] In some embodiments, the real-time capacitance value may be sampled multiple times in one response cycle, and the average of the multiple real-time capacitance values ​​may be used as the final real-time capacitance value. Specifically, one capacitance value is sampled in each sampling cycle, and each response cycle may include several sampling cycles, so that several capacitance values ​​may be obtained in each response cycle, and the real-time capacitance value of the current response cycle is obtained according to the several capacitance values.

[0072] For example, the real-time value of the capacitance is collected in each sampling cycle to obtain N real-time values ​​of the capacitance, wherein the response cycle includes N sampling cycles, and N is an integer greater than or equal to 1, and then the N capacitance values ​​are arithmetic averaged and filtered to obtain the final real-time value of the capacitance, and the final real-time value of the capacitance is used as the real-time value of the capacitance of the current response cycle.

[0073] S32, determining a capacitance change according to the real-time capacitance value;

[0074] During driving, as the temperature changes, the capacitance value of the steering wheel collected in real time changes. If the change in capacitance is caused by temperature, the capacitance change needs to be compensated into the empty wheel baseline value.

[0075] Therefore, the capacitance variation needs to be determined. Specifically, a third difference is obtained, where the third difference is the difference between the capacitance real-time value of the current response cycle and the capacitance real-time value of the previous response cycle, and the third difference is determined as the capacitance variation.

[0076] First, determine whether the real-time value of the capacitance has changed. If it has changed, record the real-time value before the change, that is, the real-time value of the capacitance in the previous response cycle, and subtract the current collected real-time value of the capacitance from the real-time value before the change to obtain the capacitance change.

[0077] S33, if the capacitance change is greater than or equal to a first preset threshold, maintaining the target empty disk baseline value as an initial empty disk baseline value, wherein the initial empty disk baseline value is an empty disk baseline value of a previous response cycle, and the empty disk baseline value is a capacitance value of the steering wheel collected when no finger is placed on the steering wheel;

[0078] The change in capacitance may be caused by temperature or by a person holding the steering wheel. Only when the capacitance change is caused by temperature will the empty wheel baseline value be compensated. Since the capacitance change caused by a person holding the steering wheel is generally larger, while the capacitance change caused by temperature is smaller, the first preset threshold value may be used to distinguish the capacitance change to determine whether it is caused by temperature or by a person holding the steering wheel.

[0079] If the capacitance change is greater than or equal to the first preset threshold, indicating that the capacitance change is caused by a person holding the steering wheel, the target empty wheel baseline value is maintained as the initial empty wheel baseline value. The first preset threshold can be set as needed, and it can also be obtained by calibration. In the embodiment of the present application, it can be a value greater than 10 and less than 20.

[0080] S34, if the capacitance change is less than the first preset threshold, determining a first accumulated time length during which the capacitance change remains less than the first preset threshold;

[0081] S35, when the first accumulated time length is greater than a first preset time length, determining the target empty disk baseline value according to the capacitance change and the initial empty disk baseline value;

[0082] If the capacitance change is less than the first preset threshold, it indicates that the capacitance change is small, but it is still necessary to distinguish whether the small capacitance change is caused by temperature or by a human hand touching the steering wheel. Generally, the capacitance change caused by temperature is slow and long-term, while the capacitance change caused by a finger touching the steering wheel has a steeper slope and a shorter duration. Therefore, the duration of the capacitance change can be used to determine whether the capacitance change is caused by temperature or by a human hand touching the steering wheel.

[0083] The first cumulative duration is the duration during which the capacitance change remains less than the first preset threshold value, which can be obtained using a counter. Specifically, if the capacitance change is less than the first preset threshold value, a counter can be used for timing. If the value of the counter is less than the first preset duration, continue to determine whether the capacitance change is less than the first preset threshold value. If it is less than, obtain the value of the counter to obtain the first cumulative duration, and then determine whether the first cumulative duration is less than the first preset duration. If it is less than, continue to determine whether the capacitance change is less than the first preset threshold value. If it is less than, obtain the value of the counter to obtain the first cumulative duration, until the first cumulative duration is greater than or equal to the first preset duration, then determine the target empty disk baseline value based on the capacitance change and the initial empty disk baseline value.

[0084] The first preset time length can be set as needed, which can be obtained through calibration. When the capacitance change is small, the compensation speed is fast, and the first preset time length can be set to a smaller value so that temperature compensation can be performed as quickly as possible. In the embodiment of the present application, the first preset time length is a value greater than 10ms and less than 20ms.

[0085] Therefore, the embodiment of the present application distinguishes whether the capacitance change is caused by temperature through the first accumulation time, thereby preventing the capacitance change caused by finger touch from being compensated into the empty disk baseline value, thereby reducing errors.

[0086] In some embodiments, large temperature changes will also cause large changes in capacitance. Therefore, in order to more accurately compensate for the empty disk baseline value, a second preset threshold and a second preset time, as well as a third preset threshold and a third preset time may be set to determine whether the change in capacitance is caused by temperature.

[0087] Specifically, if the capacitance change is greater than or equal to the first preset threshold, before the target empty disk baseline value is maintained as the initial empty disk baseline value, as follows Figure 5 As shown, the method S300 also includes:

[0088] S37, determining whether the capacitance change is less than a second preset threshold;

[0089] S38, if yes, determining a second accumulated time length during which the capacitance change remains less than the second preset threshold value, and when the second accumulated time length is greater than the second preset time length, determining the target empty disk baseline value according to the capacitance change and the initial empty disk baseline value, wherein the first preset time length is less than the second preset time length;

[0090] S39. If not, the target empty disk baseline value is maintained as the initial empty disk baseline value.

[0091] Similarly, if the capacitance change is greater than or equal to the second preset threshold, before the target empty disk baseline value is maintained as the initial empty disk baseline value, as Figure 6 As shown, the method S300 also includes:

[0092] S40, determining whether the capacitance change is less than a third preset threshold;

[0093] S41, if yes, determining a third accumulated time length during which the capacitance change remains less than the third preset threshold value, and when the third accumulated time length is greater than the third preset time length, determining the target empty disk baseline value according to the capacitance change and the initial empty disk baseline value, wherein the second preset time length is less than the third preset time length;

[0094] S42: If not, the target empty disk baseline value is maintained as the initial empty disk baseline value.

[0095] The working process and principle of the embodiment of the present application are similar to those of the above embodiment and will not be described in detail here. The first preset threshold is less than the second preset threshold, the second preset threshold is less than the third preset threshold, and the smaller the capacitance change, the faster the compensation speed, therefore, the first preset time length is less than the second preset time length, and the second preset time length is less than the third preset time length.

[0096] The compensation stage is divided into three stages. The first stage corresponds to the first preset threshold and the first preset time, and the compensation speed is the fastest. The second stage corresponds to the second preset threshold and the second preset time, and the compensation speed is lower than the compensation speed of the first stage. The third stage corresponds to the third preset threshold and the third preset time, and the compensation speed is the slowest, which is lower than the compensation speed of the second stage.

[0097] Among them, the second preset threshold and the third preset threshold can be set as needed, and can also be obtained through calibration. In the embodiment of the present application, the second preset threshold can be a value greater than 40 and less than 50, and the third preset threshold can be a value greater than 100 and less than 200.

[0098] Similarly, the second preset time length and the third preset time length can be set as needed, and can also be obtained through calibration. In the embodiment of the present application, the second preset time length can be 50ms, and the third preset time length can be 100m.

[0099] Therefore, if the capacitance change is less than the first preset threshold, the first cumulative time is recorded, and the judgment of the first cumulative time and the first preset time is started. If the capacitance change is greater than or equal to the first preset threshold, it is judged whether the capacitance change is less than the second preset threshold. If the capacitance change is less than the second preset threshold, the second cumulative time is recorded, and the judgment of the second cumulative time and the second preset time is started. If the capacitance change is greater than or equal to the second preset threshold, it is judged whether the capacitance change is less than the third preset threshold. If the capacitance change is less than the third preset threshold, the third cumulative time is recorded, and the judgment of the third cumulative time and the third preset time is started. If the capacitance change is greater than or equal to the third preset threshold, the target empty disk baseline value is maintained as the initial empty disk baseline value.

[0100] When the capacitance change is less than the first preset threshold and the first accumulated time is greater than the first preset time, or when the capacitance change is greater than or equal to the first preset threshold and less than the second preset threshold and the second accumulated time is greater than the second preset time, or when the capacitance change is greater than or equal to the second preset threshold and less than the third preset threshold and the third accumulated time is greater than the third preset time, the target empty disk baseline value is determined according to the capacitance change and the initial empty disk baseline value.

[0101] Specifically, the capacitance variation is directly compensated into the empty disk baseline value, that is, the sum or difference between the initial empty disk baseline value and the capacitance variation is determined as the target empty disk baseline value.

[0102] The initial empty disk baseline value is the end value of the empty disk baseline value of the previous response cycle, and is also the initial value of the empty disk baseline value of the current response cycle. The sum or difference between the temperature compensation value and the initial empty disk baseline value is determined as the target empty disk baseline value. For example: if the capacitance change is ΔC, the target empty disk baseline value = initial empty disk baseline value ± ΔC.

[0103] Therefore, the hands-off detection method performs temperature compensation on the empty plate baseline value through the capacitance change to obtain the corresponding target empty plate baseline value, so that the empty plate baseline value can change with the temperature change, thereby making the subsequent hands-off detection more accurate.

[0104] S36. Determine a state of the steering wheel in a current response cycle according to the real-time capacitance value and the target empty wheel baseline value, wherein the state of the steering wheel includes Hands On and Hands Off.

[0105] The state of the steering wheel in the current response cycle is determined by comparing the difference between the real-time capacitance value and the target empty wheel baseline value with the corresponding threshold. Figure 7 As shown, step S36 includes:

[0106] S361, obtaining a first difference between the real-time capacitance value and the target empty disk baseline value;

[0107] S362: if the first difference is greater than a fourth preset threshold, determining that the state of the steering wheel in the current response cycle is Hands On;

[0108] If the first difference is greater than the fourth preset threshold, the state of the steering wheel in the current response cycle is determined to be HandsOn, indicating that there are hands holding the steering wheel. In some embodiments, in order to detect more accurately, when it is determined that the first difference is greater than the fourth preset threshold, it is necessary to wait until the state of the steering wheel is stable before determining that the state of the steering wheel in the current response cycle is HandsOn. For example: if the number of times the first difference is greater than the fourth preset threshold reaches a set number of times (such as 10 times), it is determined that the state of the steering wheel is stable, or, if the running time each time is 10ms, the cumulative time that the first difference is greater than the fourth preset threshold reaches 500ms, it is determined that the state of the steering wheel is stable, and the state of the steering wheel is determined to be Hands On, and then the state of the steering wheel is updated.

[0109] The specific value of the fourth preset threshold can be set as needed.

[0110] S363: If the first difference is less than or equal to the fourth preset threshold, determine that the state of the steering wheel in the current response cycle is Hands Off.

[0111] When it is determined that the first difference is less than the fourth preset threshold, the state of the steering wheel in the current response cycle is determined to be Hands Off, indicating that no hands are holding the steering wheel. In some embodiments, in order to detect more accurately, when it is determined that the first difference is less than the fourth preset threshold, it is necessary to wait for the state of the steering wheel to stabilize before determining that the state of the steering wheel in the current response cycle is Hands Off. For example: when the state of the steering wheel remains unchanged for 500ms, the state of the steering wheel is considered stable.

[0112] To summarize, the hands-off detection method performs temperature compensation on the empty-plate baseline value, so that the empty-plate baseline value can change with the change of temperature, and can reduce the error influence of human hands holding or touching the steering wheel on the temperature compensation, and can more accurately perform temperature compensation on the empty-plate baseline value, thereby being able to more accurately detect the state of the steering wheel.

[0113] It should be noted that in each of the above embodiments, there is not necessarily a certain order between the above steps. A person skilled in the art can understand, based on the description of the embodiments of the present application, that in different embodiments, the above steps may have different execution orders, that is, they may be executed in parallel, may be executed interchangeably, and so on.

[0114] As another aspect of the embodiment of the present application, the embodiment of the present application provides a hand-off detection device 200. The hand-off detection device 200 may be a software module, which includes several instructions stored in the memory of the controller 13. The processor may access the memory and call the instructions for execution to complete the hand-off detection method described in the above embodiments.

[0115] In some embodiments, the hand-off detection device 200 may also be constructed by hardware devices, for example, the hand-off detection device 200 may be constructed by one or more chips, and the chips may work in coordination with each other to complete the hand-off detection methods described in the above embodiments. For another example, the hand-off detection device 200 may also be constructed by various logic devices, such as a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a single-chip microcomputer, an ARM (Acorn RISC Machine) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination of these components.

[0116] See also Figure 8 , Figure 8 An embodiment of the present application provides a hand-off detection device 200 , which includes an acquisition module 21 , a first determination module 22 , a holding module 23 , a second determination module 24 , a third determination module 25 and a fourth determination module 26 .

[0117] The acquisition module 21 is used to obtain the real-time capacitance value of the steering wheel in the current response cycle;

[0118] The first determination module 22 is used to determine the capacitance change according to the real-time capacitance value;

[0119] The holding module 23 is used to maintain the target empty disk baseline value as the initial empty disk baseline value if the capacitance change is greater than or equal to the first preset threshold, wherein the initial empty disk baseline value is the empty disk baseline value of the previous response cycle, and the empty disk baseline value is the capacitance value of the steering wheel collected when no finger is placed on the steering wheel;

[0120] The second determination module 24 is used to determine a first accumulated time length during which the capacitance change remains less than the first preset threshold value if the capacitance change is less than the first preset threshold value;

[0121] The third determination module 25 is used for determining the target empty disk baseline value according to the capacitance change and the initial empty disk baseline value when the first accumulated time length is greater than the first preset time length;

[0122] The fourth determination module 26 is used to determine the state of the steering wheel in the current response cycle according to the real-time value of the capacitance and the target empty wheel baseline value, wherein the state of the steering wheel includes Hands On and Hands Off.

[0123] Therefore, the hands-off detection device performs temperature compensation on the empty disk baseline value, so that the empty disk baseline value can change with the change of temperature, and can reduce the error influence of human hands holding or touching the steering wheel on the temperature compensation, and can more accurately perform temperature compensation on the empty disk baseline value, thereby being able to more accurately detect the state of the steering wheel.

[0124] It should be noted that, since the hand-off detection device and the hand-off detection method in the above embodiment are based on the same inventive concept, the corresponding contents in the above method embodiment are also applicable to the device embodiment and will not be described in detail here.

[0125] The present application also provides a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are executed by one or more processors, for example Figure 2 A processor 131 in the embodiment may enable the one or more processors to execute the hand-off detection method in any of the above method embodiments.

[0126] An embodiment of the present application also provides a computer program product, which includes a computer program stored on a non-transitory computer-readable storage medium, and the computer program includes program instructions. When the program instructions are executed by the controller 13, the controller 13 executes any one of the hand-off detection methods.

[0127] To sum up, the hands-off detection device performs temperature compensation on the empty disk baseline value, so that the empty disk baseline value can change with the change of temperature, and can reduce the error influence of human hands holding or touching the steering wheel on the temperature compensation, and can more accurately perform temperature compensation on the empty disk baseline value, thereby being able to more accurately detect the state of the steering wheel.

[0128] The above described device or equipment embodiments are merely illustrative, wherein the unit modules described as separate components may or may not be physically separated, and the components displayed as module units may or may not be physical units, that is, they may be located in one place, or may be distributed on multiple network module units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment.

[0129] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the relevant technology can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the hand-off detection method described in each embodiment or some parts of the embodiment.

[0130] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they may still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting a hand leaving the hand, characterized in that: The method comprises: Get the real-time capacitance value of the steering wheel in the current response cycle; Determine the capacitance change according to the real-time capacitance value; If the capacitance change is greater than or equal to a first preset threshold, the target empty disk baseline value is maintained as an initial empty disk baseline value, wherein the initial empty disk baseline value is an empty disk baseline value of a previous response cycle, and the empty disk baseline value is a capacitance value of the steering wheel collected when no finger is placed on the steering wheel; If the capacitance change is less than the first preset threshold, determining a first accumulated time length during which the capacitance change remains less than the first preset threshold; When the first accumulated time length is greater than a first preset time length, determining the target empty disk baseline value according to the capacitance change and the initial empty disk baseline value; The state of the steering wheel in the current response cycle is determined according to the real-time capacitance value and the target empty wheel baseline value, wherein the state of the steering wheel includes Hands On and Hands Off.

2. The method according to claim 1, characterized in that Before maintaining the target empty disk baseline value as the initial empty disk baseline value, the method further includes: Determining whether the capacitance change is less than a second preset threshold; If yes, determining a second accumulated time duration during which the capacitance change remains less than the second preset threshold value, and when the second accumulated time duration is greater than the second preset time duration, determining the target empty disk baseline value according to the capacitance change and the initial empty disk baseline value, wherein the first preset time duration is less than the second preset time duration; If not, the target empty disk baseline value is maintained as the initial empty disk baseline value.

3. The method according to claim 2, characterized in that Before maintaining the target empty disk baseline value as the initial empty disk baseline value, the method further includes: Determining whether the capacitance change is less than a third preset threshold; If yes, determining a third accumulated time length during which the capacitance change remains less than the third preset threshold value, and when the third accumulated time length is greater than the third preset time length, determining the target empty disk baseline value according to the capacitance change and the initial empty disk baseline value, wherein the second preset time length is less than the third preset time length; If not, the target empty disk baseline value is maintained as the initial empty disk baseline value.

4. The method according to claim 1, characterized in that: The step of determining the target empty disk baseline value according to the capacitance change and the initial empty disk baseline value includes: The sum or difference between the initial empty disk baseline value and the capacitance variation is determined as the target empty disk baseline value.

5. The method according to claim 1, characterized in that Determining the state of the steering wheel in the current response cycle according to the real-time capacitance value and the target empty wheel baseline value includes: Acquire a first difference between the real-time capacitance value and the target empty disk baseline value; If the first difference is greater than a fourth preset threshold, determining that the state of the steering wheel in the current response cycle is HandsOn; If the first difference is less than or equal to the fourth preset threshold, it is determined that the state of the steering wheel in the current response cycle is Hands Off.

6. The method according to any one of claims 1 to 5, characterized in that: The step of obtaining the real-time capacitance value of the current response cycle includes: Acquire a first capacitance value collected by a sensing channel of a capacitance sensor, wherein the first capacitance value is a capacitance value of an actual steering wheel; Acquire a second capacitance value collected by a reference channel of the capacitance sensor, wherein the second capacitance value is a capacitance value of a simulated steering wheel; A second difference between the first capacitance value and the second capacitance value is determined as the capacitance real-time value.

7. The method according to claim 6, characterized in that The determining the capacitance change amount according to the real-time capacitance value comprises: Acquire a third difference, wherein the third difference is a difference between the real-time value of the capacitance in a current response cycle and the real-time value of the capacitance in a previous response cycle; The third difference is determined as the capacitance variation.

8. A controller, characterized in that: The controller comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the hand-off detection method as described in any one of claims 1-7.

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