A method, system, controller and apparatus for detecting hands-off of a steering wheel

Abstract

The application discloses a kind of hand-off detection method, system, controller and device of steering wheel, it is related to detection field, comprising: the first end and the second end of control sampling capacitor are connected with power supply first preset time, to be charged to ground capacitor and sampling capacitor, and obtain first voltage by acquisition end;The second end of control sampling capacitor is connected with ground first preset time, to be discharged to ground capacitor and sampling capacitor, and obtain second voltage by acquisition end;When the absolute value of the difference of first voltage and second voltage is greater than preset value, determine that the hand of user has not left steering wheel.By sampling capacitor and the detection of the capacitance of ground capacitor by controller, without integrated chip, can be changed by changing the capacitance of sampling capacitor to achieve change parameter, the degree of freedom of configuration is improved.At the same time, only by charging and discharging of the same time to determine the capacitance of ground capacitor and then determine whether the hand of user leaves steering wheel, the process of test is simpler.

Description

Technical Field

[0001] The present invention relates to the field of detection, and in particular to a method, system, controller and device for detecting hands-off steering wheel. Background Art

[0002] The current automotive market is seeing an increasing number of safety-related applications, one of which is hands-off detection. This typically requires an alarm to sound when a person's hands are off the steering wheel, or even trigger autonomous driving. Related technologies often use integrated chips that integrate a sinusoidal excitation source and a signal processing module. By analyzing the sine wave returned from the steering wheel, the chip can determine whether the person's hands are off the steering wheel. However, integrated chips have limited flexibility, with their components and parameters often fixed, resulting in limited configuration flexibility. Summary of the Invention

[0003] The purpose of the present invention is to provide a steering wheel hands-off detection method, system, controller and device, which do not require an integrated chip and can change parameters by changing the capacitance value of a sampling capacitor, thereby increasing the degree of freedom of configuration and simplifying the testing process.

[0004] To solve the above technical problems, the present invention provides a method for detecting a hand-off of a steering wheel, which is applied to a controller in a steering wheel hand-off detection device. The steering wheel hand-off detection device further includes a ground capacitor and a sampling capacitor. A first end of the ground capacitor is connected to a first end of the sampling capacitor, and a common end thereof is connected to a power supply and a sampling end of the controller, respectively. A second end of the ground capacitor is grounded. The capacitance of the ground capacitor is positively correlated with the distance between the user's hand and the steering wheel. A second end of the sampling capacitor is connected to a power supply or ground.

[0005] The steering wheel hands-off detection method comprises:

[0006] Controlling the first end and the second end of the sampling capacitor to be connected to a power supply for a first preset time to charge the ground capacitor and the sampling capacitor, and obtaining a first voltage through the sampling end;

[0007] controlling the second end of the sampling capacitor to be connected to the ground for a first preset time to discharge the ground capacitance and the sampling capacitor, and obtaining a second voltage through the sampling end;

[0008] When the absolute value of the difference between the first voltage and the second voltage is greater than a preset value, it is determined that the user's hands have not left the steering wheel.

[0009] On the other hand, the steering wheel hand-off detection device further includes a first controllable switch and a second controllable switch, wherein a fixed end of the first controllable switch is connected to the ground capacitor and the first end of the sampling capacitor, a first movable end of the first controllable switch is connected to the power supply, a second movable end of the first controllable switch is connected to the acquisition end of the controller, a third movable end of the first controllable switch is grounded, a fixed end of the second controllable switch is connected to the second end of the sampling capacitor, a first movable end of the second controllable switch is connected to the power supply, and a second movable end of the second controllable switch is grounded;

[0010] Before controlling the second end of the sampling capacitor to be connected to a power supply for a first preset time to charge the ground capacitor and the sampling capacitor, the method further includes:

[0011] The fixed end of the first controllable switch is controlled to be connected to the third active end, and the fixed end of the second controllable switch is controlled to be connected to the second active end, so as to discharge the electric energy stored in the sampling capacitor and the ground capacitor.

[0012] On the other hand, controlling the second end of the sampling capacitor to be connected to a power supply for a first predetermined time to charge the ground capacitor and the sampling capacitor includes:

[0013] The fixed end of the first controllable switch is controlled to be connected to the second active end for a first preset time, and the fixed end of the second controllable switch is controlled to be connected to its own first active end for a first preset time to charge the ground capacitor and the sampling capacitor.

[0014] On the other hand, after controlling the second end of the sampling capacitor to be connected to the power supply for a first preset time, the method further includes:

[0015] Controlling the fixed end of the first controllable switch to be connected to the first active end for a first preset time, and the fixed end of the second controllable switch to be connected to the first active end for a first preset time, so that the voltage across the sampling capacitor reaches the power supply voltage;

[0016] Enter the step of controlling the second end of the sampling capacitor to be connected to the ground for a first preset time.

[0017] On the other hand, controlling the second end of the sampling capacitor to be connected to the ground for a first preset time to discharge the ground capacitance and the sampling capacitor includes:

[0018] The fixed end of the first controllable switch is controlled to be connected to the second active end, and the fixed end of the second controllable switch is controlled to be connected to the second active end, so as to discharge the ground capacitor and the sampling capacitor.

[0019] On the other hand, when the absolute value of the difference between the first voltage and the second voltage is greater than a preset value, determining that the user's hand has not left the steering wheel includes:

[0020] The expression for determining the first voltage is: ;

[0021] The expression for determining the second voltage is ;

[0022] The capacitance to ground is determined based on the absolute value of the difference between the first voltage and the second voltage. The absolute value of the difference is expressed as: ;

[0023] Among them, V Charge is the first voltage, V Discharge is the second voltage, VCC is the voltage of the power supply, V Diff is the absolute value of the difference, C Sensor is the capacitance value of the sampling capacitor, C Hand is the capacitance value of the ground capacitor.

[0024] To solve the above technical problems, the present invention further provides a steering wheel hands-off detection system, including a controller for use in a steering wheel hands-off detection device. The steering wheel hands-off detection device further includes a ground capacitor and a sampling capacitor. A first end of the ground capacitor is connected to a first end of the sampling capacitor, and a common end thereof is connected to a power supply and a sampling end of the controller, respectively. A second end of the ground capacitor is grounded. The capacitance of the ground capacitor is positively correlated with the distance between the user's hand and the steering wheel. The second end of the sampling capacitor is connected to a power supply or ground.

[0025] The steering wheel hands-off detection system comprises:

[0026] a charging unit, configured to control the first and second ends of the sampling capacitor to be connected to a power source for a first preset time, so as to charge the ground capacitor and the sampling capacitor, and obtain a first voltage through the sampling end;

[0027] a discharge unit, configured to control the second end of the sampling capacitor to be connected to the ground for a first preset time, so as to discharge the ground capacitance and the sampling capacitor, and obtain a second voltage through the sampling end;

[0028] The hands-off judgment unit is configured to determine that the user's hands have not left the steering wheel when the absolute value of the difference between the first voltage and the second voltage is greater than a preset value.

[0029] In order to solve the above technical problems, the present invention also provides a controller for implementing the steps of the above steering wheel hand-off detection method when executing the computer program.

[0030] In order to solve the above technical problems, the present invention further provides a steering wheel hands-off detection device, comprising:

[0031] a ground capacitor, wherein a first end of the ground capacitor is connected to a first end of the sampling capacitor, and a common end of the connected capacitors is respectively connected to a power supply and a collection end of a controller, a second end of the ground capacitor is grounded, and a capacitance value of the ground capacitor is positively correlated with a distance between a user's hand and the steering wheel;

[0032] The sampling capacitor, wherein the second end of the sampling capacitor is connected to a power supply or a ground;

[0033] The controller mentioned above.

[0034] On the other hand, it also includes a first controllable switch and a second controllable switch;

[0035] The fixed end of the first controllable switch is connected to the capacitor to ground and the first end of the sampling capacitor, the first movable end of the first controllable switch is connected to the power supply, the second movable end of the first controllable switch is connected to the acquisition end of the controller, the third movable end of the first controllable switch is grounded, and the first controllable switch is configured to connect its fixed end to its first movable end, second movable end, or third movable end;

[0036] The fixed end of the second controllable switch is connected to the second end of the sampling capacitor, the first active end of the second controllable switch is connected to the power supply, the second active end of the second controllable switch is grounded, and the second controllable switch is used to connect its fixed end to its first active end or its second active end.

[0037] The present invention discloses a method, system, controller and device for detecting when the user's hand has left the steering wheel, which relates to the field of detection, including: controlling the first and second ends of the sampling capacitor to be connected to a power supply for a first preset time to charge the ground capacitor and the sampling capacitor, and obtaining a first voltage through the acquisition end; controlling the second end of the sampling capacitor to be connected to the ground for a first preset time to discharge the ground capacitor and the sampling capacitor, and obtaining a second voltage through the acquisition end; when the absolute value of the difference between the first voltage and the second voltage is greater than a preset value, determining that the user's hand has not left the steering wheel. The capacitance value of the ground capacitor is detected by the sampling capacitor and the controller, without the need for an integrated chip, and the parameters can be changed by changing the capacitance value of the sampling capacitor, thereby improving the degree of freedom of configuration. At the same time, the capacitance value of the ground capacitor is determined only by charging and discharging for the same time, thereby determining whether the user's hand has left the steering wheel, making the testing process simpler. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the prior art and the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 A flowchart of a method for detecting hands-off steering wheel provided by the present invention;

[0040] Figure 2 A schematic structural diagram of a steering wheel hands-off detection device provided by the present invention;

[0041] Figure 3 A schematic diagram of a voltage value collected by a collection terminal of a controller provided by the present invention;

[0042] Figure 4 This is a structural schematic diagram of a steering wheel hands-off detection system provided by the present invention. DETAILED DESCRIPTION

[0043] The core of the present invention is to provide a steering wheel hands-off detection method, system, controller and device, which do not require an integrated chip and can change parameters by changing the capacitance value of the sampling capacitor, thereby increasing the configuration freedom and simplifying the testing process.

[0044] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0045] Figure 1 This is a flow chart of a method for detecting a hand-off of a steering wheel provided by the present invention. The method is applied to a controller in a steering wheel hand-off detection device. The steering wheel hand-off detection device further includes a ground capacitor C1 and a sampling capacitor C2. A first end of the ground capacitor C1 is connected to a first end of the sampling capacitor C2, and a common end thereof is connected to a power supply and a collection end of the controller, respectively. A second end of the ground capacitor C1 is grounded. The capacitance of the ground capacitor C1 is positively correlated with the distance between the user's hand and the steering wheel. A second end of the sampling capacitor C2 is connected to a power supply or ground.

[0046] The methods for detecting hands-off of the steering wheel include:

[0047] S11: controlling the first end and the second end of the sampling capacitor to be connected to a power supply for a first preset time to charge the ground capacitor and the sampling capacitor, and obtaining a first voltage through the sampling end;

[0048] S12: Controlling the second end of the sampling capacitor to be connected to the ground for a first preset time to discharge the ground capacitance and the sampling capacitor, and obtaining a second voltage through the sampling end;

[0049] S13: When the absolute value of the difference between the first voltage and the second voltage is greater than a preset value, it is determined that the user's hands have not left the steering wheel.

[0050] The current automotive market is seeing an increasing number of safety-related applications, one of which is hands-off detection. This typically requires an alarm to sound when a person's hands are off the steering wheel, or even trigger autonomous driving. Related technologies often use integrated chips that integrate a sinusoidal excitation source and a signal processing module. By analyzing the sine wave returned from the steering wheel, the chip can determine whether the person's hands are off the steering wheel. However, integrated chips have limited flexibility, with their components and parameters often fixed, resulting in limited configuration flexibility.

[0051] The present invention mainly charges and discharges the sampling capacitor C2 in a certain strategy, and detects the charging voltage value and the discharging voltage value on the sampling capacitor C2 through the sampling end of the controller, and finally determines whether there is human hand contact by comparing the change in the difference between the charging voltage value and the discharging voltage value. It should be noted that if the steering wheel is touched by a human hand, then the ground capacitance C1 exists, and if it is not touched by a human hand, then the ground capacitance C1 does not exist. The size of the ground capacitance C1 is not only positively correlated with the distance between the user's hand and the steering wheel, but also related to the area of ​​contact between the user and the steering wheel. For example, the ground capacitance C1 of the entire hand covering the steering wheel will be greater than the ground capacitance C1 of several fingers touching the steering wheel. Since the ground capacitance C1 needs to be collected through charging and discharging, the charging time and the discharging time need to be equal, otherwise the voltage difference due to the different time will affect the capacitance value of the ground capacitance C1 that needs to be collected.

[0052] Furthermore, since there may be two situations where the user takes off the steering wheel handle and puts his hands on the steering wheel, that is, the magnitude relationship between the first voltage and the second voltage is not fixed, it is necessary to consider the absolute value issue in order to more accurately determine whether the steering wheel is left.

[0053] The present invention discloses a method for detecting when a hand has left the steering wheel, which relates to the field of detection and includes: controlling the second end of the sampling capacitor C2 to be connected to a power supply for a first preset time to charge the ground capacitor C1 and the sampling capacitor C2, and obtaining a first voltage through the acquisition end; controlling the second end of the sampling capacitor C2 to be connected to the ground for a first preset time to discharge the ground capacitor C1 and the sampling capacitor C2, and obtaining a second voltage through the acquisition end; when the absolute value of the difference between the first voltage and the second voltage is greater than a preset value, determining that the user's hand has not left the steering wheel. The capacitance value of the ground capacitor C1 is detected by the sampling capacitor C2 and a controller, without the need for an integrated chip, and the parameters can be changed by changing the capacitance value of the sampling capacitor C2, thereby increasing the degree of freedom of configuration. At the same time, the capacitance value of the ground capacitor C1 is determined only by charging and discharging for the same time, thereby determining whether the user's hand has left the steering wheel, making the testing process simpler.

[0054] Based on the above embodiment:

[0055] Figure 2 A schematic structural diagram of a steering wheel hands-off detection device provided by the present invention;

[0056] Figure 3 A schematic diagram of a voltage value collected by a collection terminal of a controller provided by the present invention;

[0057] In some embodiments, the steering wheel hand-off detection device further includes a first controllable switch S1 and a second controllable switch S2, wherein a fixed end of the first controllable switch S1 is connected to a ground capacitor C1 and a first end of a sampling capacitor C2, a first movable end of the first controllable switch S1 is connected to a power supply, a second movable end of the first controllable switch S1 is connected to a collection end of a controller, a third movable end of the first controllable switch S1 is grounded, a fixed end of the second controllable switch S2 is connected to a second end of the sampling capacitor C2, a first movable end of the second controllable switch S2 is connected to a power supply, and a second movable end of the second controllable switch S2 is grounded;

[0058] Before controlling the second end of the sampling capacitor C2 to be connected to the power supply for a first predetermined time to charge the ground capacitor C1 and the sampling capacitor C2, the method further includes:

[0059] The fixed end of the first controllable switch S1 is controlled to be connected to the third active end, and the fixed end of the second controllable switch S2 is controlled to be connected to the second active end, so as to discharge the electric energy stored in the sampling capacitor C2 and the ground capacitor C1.

[0060] Figure 2 The first active terminal of the first controllable switch S1 is the power supply VCC, the second active terminal is the A / D digital-to-analog conversion acquisition terminal of the controller, and the third active terminal is the ground GND. The first active terminal of the second controllable switch S2 is the power supply VCC, and the second active terminal is the ground GND. Figure 3The horizontal axis is time, the vertical axis is V ADC is the voltage at the controller sampling terminal.

[0061] First, before detection, it is necessary to remove interference factors, that is, clear the charge in the sampling capacitor C2 and the ground capacitor C1 (if any), that is, Figure 2 The first controllable switch S1 and the second controllable switch S2 are both switched to the GND state, so that the sampling capacitor C2 and the ground capacitor C1 are completely discharged. This process corresponds to Figure 3 In this way, the subsequent charging process will not be affected by the charge stored in the ground capacitor C1 and the sampling capacitor C2.

[0062] In some embodiments, controlling the second end of the sampling capacitor C2 to be connected to a power source for a first predetermined time to charge the ground capacitor C1 and the sampling capacitor C2 includes:

[0063] The fixed terminal of the first controllable switch S1 is connected to the second active terminal for a first preset time, and the fixed terminal of the second controllable switch S2 is connected to its own first active terminal for a first preset time to charge the ground capacitor C1 and the sampling capacitor C2.

[0064] Then the second controllable switch S2 is switched to the first active end to charge the ground capacitor C1 and the sampling capacitor C2, and the first controllable switch S1 is switched to the second active end. When the charging is complete, the controller can obtain a charging voltage of the sampling capacitor C2, that is, the first voltage. This process corresponds to Figure 3 The second stage.

[0065] The total capacitance of the ground capacitor C1 and the sampling capacitor C2 is CTotal, and the expression of the total capacitance is: ;

[0066] The expression for the sum of the charges of the sampling capacitor C2 and the ground capacitor C1, Q, is: , it is derived that , and finally the first voltage is .

[0067] Among them, V Charge is the first voltage, VCC is the voltage of the power supply, C Sensor is the capacitance value of the sampling capacitor C2, C Hand is the capacitance value of the ground capacitor C1.

[0068] In some embodiments, after controlling the second end of the sampling capacitor C2 to be connected to the power supply for a first preset time, the method further includes:

[0069] Controlling the fixed end of the first controllable switch S1 to be connected to the first active end for a first preset time, and controlling the fixed end of the second controllable switch S2 to be connected to the first active end for a first preset time, so that the voltage across the sampling capacitor C2 reaches the power supply voltage;

[0070] Enter the step of controlling the second end of the sampling capacitor C2 to be connected to the ground for a first preset time.

[0071] Keep the second controllable switch S2 unchanged (first active end), and then switch the first controllable switch S1 to the first active end. At this time, the sampling capacitor C2 can be charged to the value of the maximum voltage VCC. This process corresponds to Figure 3 Since both the first controllable switch S1 and the second controllable switch S2 are switched to VCC, there is no potential difference between the two electrodes of the sampling capacitor C2.

[0072] Can get , Q Sensor is the charge in the sampling capacitor C2 after charging, Q Hand is the amount of charge in the ground capacitor C1 after charging.

[0073] In some embodiments, controlling the second end of the sampling capacitor C2 to be connected to the ground for a first predetermined time to discharge the ground capacitor C1 and the sampling capacitor C2 includes:

[0074] The fixed end of the first controllable switch S1 is controlled to be connected to the second active end, and the fixed end of the second controllable switch S2 is controlled to be connected to the second active end, so as to discharge the ground capacitor C1 and the sampling capacitor C2.

[0075] Switch the first controllable switch S1 to the second active end, and switch the second controllable switch S2 to the second active end. At this time, the ground capacitor C1 is discharged to GND through the sampling capacitor C2, so that the voltage on the sampling capacitor C2 starts to drop from VCC until it stabilizes, thereby obtaining the second voltage V Discharge , this process corresponds to Figure 3 The fourth stage.

[0076] because , , the total charge before and after charging and discharging remains unchanged, so , it is derived that , and finally the second voltage is .

[0077] in is the charge in the sampling capacitor C2 after discharge, is the amount of charge in the ground capacitor C1 after discharge.

[0078] In some embodiments, when the absolute value of the difference between the first voltage and the second voltage is greater than a preset value, determining that the user's hands have not left the steering wheel includes:

[0079] The expression for determining the first voltage is ;

[0080] The expression for determining the second voltage is ;

[0081] The capacitance C1 to ground is determined based on the absolute value of the difference between the first voltage and the second voltage. The absolute value of the difference is expressed as ;

[0082] Among them, V Charge is the first voltage, V Discharge is the second voltage, VCC is the voltage of the power supply, V Diff is the absolute value of the difference, C Sensor is the capacitance value of the sampling capacitor C2, C Hand is the capacitance of ground capacitor C1. VDiff is the difference in voltage across sampling capacitor C2 before and after charging and discharging. This difference can be used to determine whether a hand is approaching or touching the ground capacitor C1, thereby achieving hands-off detection.

[0083] Figure 4 This is a schematic structural diagram of a steering wheel hand-off detection system provided by the present invention. The steering wheel hand-off detection system is applied to a controller in a steering wheel hand-off detection device. The steering wheel hand-off detection device also includes a ground capacitor C1 and a sampling capacitor C2. A first end of the ground capacitor C1 is connected to a first end of the sampling capacitor C2, and their common end is respectively connected to a power supply and a sampling end of the controller. A second end of the ground capacitor C1 is grounded. The capacitance value of the ground capacitor C1 is positively correlated with the distance between the user's hand and the steering wheel. A second end of the sampling capacitor C2 is connected to the power supply or ground.

[0084] The hands-off steering wheel detection system includes:

[0085] The charging unit 41 is configured to control the first and second terminals of the sampling capacitor C2 to be connected to a power source for a first preset time, so as to charge the ground capacitor C1 and the sampling capacitor C2, and obtain a first voltage through the sampling terminal;

[0086] The discharge unit 42 is used to control the second end of the sampling capacitor C2 to be connected to the ground for a first preset time, so as to discharge the ground capacitor C1 and the sampling capacitor C2, and obtain a second voltage through the sampling end;

[0087] The hands-off judgment unit 43 is configured to determine that the user's hands have not left the steering wheel when the absolute value of the difference between the first voltage and the second voltage is greater than a preset value.

[0088] Based on the above embodiment:

[0089] The steering wheel hand-off detection device also includes a first controllable switch S1 and a second controllable switch S2. The fixed end of the first controllable switch S1 is connected to the ground capacitor C1 and the first end of the sampling capacitor C2. The first movable end of the first controllable switch S1 is connected to a power supply. The second movable end of the first controllable switch S1 is connected to the acquisition end of the controller. The third movable end of the first controllable switch S1 is grounded. The fixed end of the second controllable switch S2 is connected to the second end of the sampling capacitor C2. The first movable end of the second controllable switch S2 is connected to the power supply. The second movable end of the second controllable switch S2 is grounded.

[0090] Also includes:

[0091] The discharge unit is used to control the fixed end of the first controllable switch S1 to be connected to the third active end, and the fixed end of the second controllable switch S2 to be connected to the second active end, so as to discharge the electric energy stored in the sampling capacitor C2 and the ground capacitor C1.

[0092] The charging unit 41 is specifically configured to control the fixed end of the first controllable switch S1 to be connected to the second active end for a first preset time, and the fixed end of the second controllable switch S2 to be connected to its own first active end for a first preset time, so as to charge the ground capacitor C1 and the sampling capacitor C2.

[0093] Also includes:

[0094] The voltage adjustment unit is used to control the fixed end of the first controllable switch S1 to be connected to the first active end for a first preset time, and the fixed end of the second controllable switch S2 to be connected to the first active end for a first preset time, so that the voltage across the sampling capacitor C2 reaches the power supply voltage.

[0095] The discharge unit 42 is specifically configured to control the fixed end of the first controllable switch S1 to be connected to the second movable end, and the fixed end of the second controllable switch S2 to be connected to the second movable end, so as to discharge the ground capacitor C1 and the sampling capacitor C2.

[0096] The hand-off judgment unit 43 is used to determine the expression of the first voltage: ;

[0097] The expression for determining the second voltage is ;

[0098] The capacitance C1 to ground is determined based on the absolute value of the difference between the first voltage and the second voltage. The absolute value of the difference is expressed as ;

[0099] Among them, V Charge is the first voltage, V Discharge is the second voltage, VCC is the voltage of the power supply, VDiff is the absolute value of the difference, C Sensor is the capacitance value of the sampling capacitor C2, C Hand is the capacitance value of the ground capacitor C1.

[0100] For an introduction to the steering wheel hand-off detection system provided in this application, please refer to the above embodiments and will not be repeated here.

[0101] The present application also provides a controller for implementing the steps of the above-mentioned steering wheel hand-off detection method when executing a computer program.

[0102] For an introduction to the controller provided in this application, please refer to the above embodiments and will not be repeated here.

[0103] Figure 2 This is a schematic structural diagram of a steering wheel hands-off detection device provided by the present invention, the steering wheel hands-off detection device comprising:

[0104] A ground capacitor C1, wherein a first end of the ground capacitor C1 is connected to a first end of the sampling capacitor C2, and a common end of the connected capacitors is respectively connected to a power supply and a sampling end of the controller. A second end of the ground capacitor C1 is grounded. The capacitance of the ground capacitor C1 is positively correlated with the distance between the user's hand and the steering wheel.

[0105] A sampling capacitor C2, wherein a second end of the sampling capacitor C2 is connected to a power supply or a ground;

[0106] The controller mentioned above.

[0107] In some embodiments, the system further includes a first controllable switch S1 and a second controllable switch S2;

[0108] The fixed end of the first controllable switch S1 is connected to the first end of the ground capacitor C1 and the sampling capacitor C2, the first movable end of the first controllable switch S1 is connected to the power supply, the second movable end of the first controllable switch S1 is connected to the acquisition end of the controller, the third movable end of the first controllable switch S1 is grounded, and the first controllable switch S1 is used to connect its fixed end to its first movable end, second movable end, or third movable end;

[0109] The fixed end of the second controllable switch S2 is connected to the second end of the sampling capacitor C2, the first active end of the second controllable switch S2 is connected to the power supply, the second active end of the second controllable switch S2 is grounded, and the second controllable switch S2 is used to connect its fixed end to its first active end or its second active end.

[0110] For an introduction to the steering wheel hand-off detection device provided in this application, please refer to the above embodiments and will not be repeated here.

[0111] It should also be noted that, in this specification, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0112] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0113] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for detecting hands-off steering wheel, characterized in that: A controller for use in a hands-off detection device for a steering wheel, the hands-off detection device further comprising a ground capacitor and a sampling capacitor, wherein a first end of the ground capacitor is connected to a first end of the sampling capacitor, and a common end thereof is connected to a power supply and a collection end of the controller, respectively; a second end of the ground capacitor is grounded, a capacitance value of the ground capacitor is positively correlated with a distance between a user's hand and the steering wheel, and a second end of the sampling capacitor is connected to a power supply or ground; The steering wheel hands-off detection method comprises: Controlling the first end and the second end of the sampling capacitor to be connected to a power supply for a first preset time to charge the ground capacitor and the sampling capacitor, and obtaining a first voltage through the sampling end; controlling the second end of the sampling capacitor to be connected to the ground for a first preset time to discharge the ground capacitance and the sampling capacitor, and obtaining a second voltage through the sampling end; When the absolute value of the difference between the first voltage and the second voltage is greater than a preset value, it is determined that the user's hands have not left the steering wheel.

2. The method for detecting hands-off steering wheel according to claim 1, wherein: The hands-off detection device for the steering wheel further includes a first controllable switch and a second controllable switch, wherein a fixed end of the first controllable switch is connected to the ground capacitor and the first end of the sampling capacitor, a first movable end of the first controllable switch is connected to the power supply, a second movable end of the first controllable switch is connected to the acquisition end of the controller, a third movable end of the first controllable switch is grounded, a fixed end of the second controllable switch is connected to the second end of the sampling capacitor, a first movable end of the second controllable switch is connected to the power supply, and a second movable end of the second controllable switch is grounded; Before controlling the second end of the sampling capacitor to be connected to a power supply for a first preset time to charge the ground capacitor and the sampling capacitor, the method further includes: The fixed end of the first controllable switch is controlled to be connected to the third active end, and the fixed end of the second controllable switch is controlled to be connected to the second active end, so as to discharge the electric energy stored in the sampling capacitor and the ground capacitor.

3. The method for detecting hands-off steering wheel according to claim 2, wherein: Controlling the second end of the sampling capacitor to be connected to a power supply for a first preset time to charge the ground capacitor and the sampling capacitor includes: The fixed end of the first controllable switch is controlled to be connected to the second active end for a first preset time, and the fixed end of the second controllable switch is controlled to be connected to its own first active end for a first preset time to charge the ground capacitor and the sampling capacitor.

4. The method for detecting hands-off steering wheel according to claim 2, wherein: After controlling the second end of the sampling capacitor to be connected to the power supply for a first preset time, the method further includes: Controlling the fixed end of the first controllable switch to be connected to the first active end for a first preset time, and the fixed end of the second controllable switch to be connected to the first active end for a first preset time, so that the voltage across the sampling capacitor reaches the power supply voltage; Enter the step of controlling the second end of the sampling capacitor to be connected to the ground for a first preset time.

5. The method for detecting hands-off steering wheel according to claim 2, wherein: Controlling the second end of the sampling capacitor to be connected to the ground for a first preset time to discharge the ground capacitance and the sampling capacitor, comprising: The fixed end of the first controllable switch is controlled to be connected to the second active end, and the fixed end of the second controllable switch is controlled to be connected to the second active end, so as to discharge the ground capacitor and the sampling capacitor.

6. The method for detecting hands-off steering wheel according to any one of claims 1 to 5, wherein: When the absolute value of the difference between the first voltage and the second voltage is greater than a preset value, determining that the user's hand has not left the steering wheel includes: The expression for determining the first voltage is: ; The expression for determining the second voltage is ; The capacitance to ground is determined based on the absolute value of the difference between the first voltage and the second voltage. The absolute value of the difference is expressed as: ; Among them, V Charge is the first voltage, V Discharge is the second voltage, VCC is the voltage of the power supply, V Diff is the absolute value of the difference, C Sensor is the capacitance value of the sampling capacitor, C Hand is the capacitance value of the ground capacitor.

7. A steering wheel hands-off detection system, characterized in that: A controller for use in a hands-off detection device for a steering wheel, the hands-off detection device further comprising a ground capacitor and a sampling capacitor, wherein a first end of the ground capacitor is connected to a first end of the sampling capacitor, and a common end thereof is connected to a power supply and a collection end of the controller, respectively; a second end of the ground capacitor is grounded, a capacitance value of the ground capacitor is positively correlated with a distance between a user's hand and the steering wheel, and a second end of the sampling capacitor is connected to a power supply or ground; The steering wheel hands-off detection system comprises: a charging unit, configured to control the second end of the sampling capacitor to be connected to a power source for a first preset time, so as to charge the ground capacitor and the sampling capacitor, and obtain a first voltage through the sampling end; a discharge unit, configured to control the second end of the sampling capacitor to be connected to the ground for a first preset time, so as to discharge the ground capacitance and the sampling capacitor, and obtain a second voltage through the sampling end; The hands-off judgment unit is configured to determine that the user's hands have not left the steering wheel when the absolute value of the difference between the first voltage and the second voltage is greater than a preset value.

8. A controller, characterized in that: The computer program is used to implement the steps of the steering wheel hand-off detection method as claimed in any one of claims 1 to 6 when executing the computer program.

9. A device for detecting a hands-off state of a steering wheel, characterized in that: include: a ground capacitor, wherein a first end of the ground capacitor is connected to a first end of the sampling capacitor, and a common end of the connected capacitors is respectively connected to a power supply and a collection end of a controller, a second end of the ground capacitor is grounded, and a capacitance value of the ground capacitor is positively correlated with a distance between a user's hand and the steering wheel; The sampling capacitor, wherein the second end of the sampling capacitor is connected to a power supply or a ground; The controller as claimed in claim 8.

10. The device for detecting the hand-off of the steering wheel according to claim 9, wherein: Also includes a first controllable switch and a second controllable switch; The fixed end of the first controllable switch is connected to the capacitor to ground and the first end of the sampling capacitor, the first movable end of the first controllable switch is connected to the power supply, the second movable end of the first controllable switch is connected to the acquisition end of the controller, the third movable end of the first controllable switch is grounded, and the first controllable switch is configured to connect its fixed end to its first movable end, second movable end, or third movable end; The fixed end of the second controllable switch is connected to the second end of the sampling capacitor, the first active end of the second controllable switch is connected to the power supply, the second active end of the second controllable switch is grounded, and the second controllable switch is used to connect its fixed end to its first active end or its second active end.

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