Detection circuit, steering wheel detection method, storage medium and program product

Abstract

The invention discloses a detection circuit, a steering wheel detection method, a storage medium and a program product, and is characterized in that a heating unit is arranged in a steering wheel of a vehicle, and the steering wheel is grounded; a source electrode of the first switch tube is electrically connected with one end of the heating unit, a drain electrode of the first switch tube is externally connected with a vehicle power supply, and a grid electrode of the first switch tube is electrically connected with a first pin of the control unit; the other end of the heating unit is electrically connected with one end of the hand-leaving actual channel, and the other end of the hand-leaving actual channel is electrically connected with the acquisition unit; a second pin of the control unit is electrically connected with a grid electrode of the second switch tube, a third pin of the control unit is electrically connected with a grid electrode of the third switch tube, a drain electrode of the second switch tube is electrically connected with the other end of the heating unit, and a source electrode of the second switch tube is electrically connected with a drain electrode of the third switch tube and one end of the hand-leaving reference channel; the source electrode of the third switch tube and the other end of the hand-off reference channel are grounded; the control unit is in communication connection with the acquisition unit.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to a detection circuit, a steering wheel detection method, a storage medium and a program product. Background Art

[0002] Hands-off detection technology is a technology used to monitor whether the driver is holding the steering wheel with both hands. It is mainly used in autonomous driving and advanced driver assistance systems. At present, in order to ensure the driver's experience when using the steering wheel, the hands-off detection circuit directly installs various functional devices on the steering wheel, such as a heating device.

[0003] However, since functional devices such as a heating device are installed on the steering wheel of the vehicle, the accuracy of the hands-off detection will be reduced. Therefore, in order to ensure the accuracy of the detection, the current hands-off detection circuit is designed to be more complicated, resulting in a higher design material cost for the steering wheel. Summary of the invention

[0004] The present invention provides a detection circuit, a steering wheel detection method, a storage medium and a program product, which solve the problem that the current hands-on / off detection circuit is relatively complex in design to ensure the accuracy of detection, thereby resulting in a high cost of design materials for the steering wheel, and realizes the design of a detection circuit integrating a detection channel and a reference channel of the detection channel by using simple units, switch tubes and channels, and improves the accuracy of hands-on / off detection based on the detection channel and the reference channel.

[0005] According to one aspect of the present invention, a detection circuit is provided, comprising: a heating unit, a collection unit, a control unit, a first switch tube, a second switch tube, a third switch tube, a hand-off actual channel and a hand-off reference channel; wherein,

[0006] The heating unit is arranged in the steering wheel of the vehicle, and the steering wheel is grounded; the source of the first switch tube is electrically connected to one end of the heating unit, the drain of the first switch tube is externally connected to the vehicle power supply, and the gate of the first switch tube is electrically connected to the first pin of the control unit; the other end of the heating unit is electrically connected to one end of the hands-off actual channel, and the other end of the hands-off actual channel is electrically connected to the acquisition unit;

[0007] The second pin of the control unit is electrically connected to the gate of the second switch tube, the third pin of the control unit is electrically connected to the gate of the third switch tube, the drain of the second switch tube is electrically connected to the other end of the heating unit, the source of the second switch tube is electrically connected to the drain of the third switch tube and one end of the hand-off reference channel respectively; the source of the third switch tube and the other end of the hand-off reference channel are both grounded;

[0008] The control unit is communicatively connected with the acquisition unit.

[0009] According to another aspect of the present invention, a steering wheel detection method is provided. The steering wheel detection method implements the detection circuit of any embodiment of the present invention. The method comprises:

[0010] The control unit controls the first switch tube, the second switch tube and the third switch tube to be turned off, and sends a first acquisition command to the acquisition unit to obtain the hand-off detection data of the actual hand-off channel acquired by the acquisition unit;

[0011] The control unit controls the first switch tube and the third switch tube to be turned off, controls the second switch tube to be turned on, and sends a second acquisition command to the acquisition unit to obtain the hand-off reference data of the hand-off reference channel and the hand-off actual channel acquired by the acquisition unit;

[0012] The control unit determines the hand-on / off state of the steering wheel of the vehicle according to the hand-off detection data, the hand-off reference data and the preset hand-off threshold.

[0013] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the steering wheel detection method described in any embodiment of the present invention when executed.

[0014] According to another aspect of the present invention, a computer program product is provided, comprising a computer program, wherein when the computer program is executed by a processor, the steering wheel detection method according to any embodiment of the present invention is implemented.

[0015] The detection circuit provided by the embodiment of the present invention adds a hand-off reference channel on the basis of the original steering wheel hand-off detection circuit, and realizes that a reference control detection circuit is added on the basis of the steering wheel hand-off detection. Based on the reference control detection circuit, a basis for the offset term (i.e., the influence of the heating unit on the steering wheel on the hand-off detection of the detection circuit) can be provided for the detection circuit, and a reference detection result is provided for the subsequent hand-off detection, so that the final detection result is more accurate. In addition, based on several simple units, switches and channels, a steering wheel hand-off detection circuit and a reference circuit can be formed, which solves the problem that the current hand-off detection circuit is relatively complex in design to ensure the accuracy of detection, thereby resulting in a high cost of design materials for the steering wheel, and realizes the use of simple units, switches and channels to design a detection circuit that integrates the detection channel and the reference channel of the detection channel.

[0016] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of 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 creative work.

[0018] Figure 1 A detection circuit provided by an embodiment of the present invention;

[0019] Figure 2 Another detection circuit provided by an embodiment of the present invention;

[0020] Figure 3 A flow chart of a steering wheel detection method provided by an embodiment of the present invention;

[0021] Figure 4 The present invention provides a flowchart of another steering wheel detection method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the 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 creative work should fall within the scope of protection of the present invention.

[0023] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0024] Figure 1 A detection circuit is provided in an embodiment of the present invention. This embodiment can be used to detect the state of a hand holding or releasing a steering wheel of a vehicle and heat the steering wheel. Figure 1As shown, the detection circuit includes: a heating unit 10, a collection unit 20, a control unit 30, a first switch tube 40, a second switch tube 50, a third switch tube 60, a hand-off actual channel 70 and a hand-off reference channel 80.

[0025] The heating unit 10 is arranged in the steering wheel of the vehicle, and the steering wheel is grounded. In actual situations, the hub of the steering wheel is grounded, and the heating unit 10 can be a steering wheel heating wire.

[0026] The source S of the first switch tube 40 is electrically connected to one end of the heating unit 10, and the drain D of the first switch tube 40 is externally connected to the vehicle power supply 90. In actual situations, the external vehicle power supply can be a 12V power supply. The gate G of the first switch tube 40 is electrically connected to the first pin pin1 of the control unit 30.

[0027] The other end of the heating unit 10 is electrically connected to one end of the actual hand-off channel 70 , and the other end of the actual hand-off channel 70 is electrically connected to the collection unit 20 .

[0028] The second pin pin2 of the control unit 30 is electrically connected to the gate G of the second switch tube 50 . The third pin pin3 of the control unit 30 is electrically connected to the gate G of the third switch tube 60 .

[0029] The drain D of the second switch tube 50 is electrically connected to the other end of the heating unit 10 , and the source S of the second switch tube 50 is electrically connected to the drain D of the third switch tube 60 and one end of the hand-off reference channel 80 .

[0030] The source S of the third switch tube 60 and the other end of the hand-off reference channel 80 are both grounded.

[0031] Optionally, the second switch tube 50 is grounded.

[0032] The control unit 30 is in communication connection with the acquisition unit 20 .

[0033] The detection circuit provided by the embodiment of the present invention adds a hand-off reference channel on the basis of the original steering wheel hand-off detection circuit, and realizes that a reference control detection circuit is added on the basis of the steering wheel hand-off detection. Based on the reference control detection circuit, a basis for the offset term (i.e., the influence of the heating unit on the steering wheel on the hand-off detection of the detection circuit) can be provided for the detection circuit, and a reference detection result is provided for the subsequent hand-off detection, so that the final detection result is more accurate. In addition, based on several simple units, switches and channels, a steering wheel hand-off detection circuit and a reference circuit can be formed, which solves the problem that the current hand-off detection circuit is relatively complex in design to ensure the accuracy of detection, thereby resulting in a high cost of design materials for the steering wheel, and realizes the use of simple units, switches and channels to design a detection circuit that integrates the detection channel and the reference channel of the detection channel.

[0034] Further, Figure 2 Another detection circuit provided by an embodiment of the present invention.

[0035] The hands-off actual channel 70 includes a first resistor R1 701 and a first capacitor C1 702 connected in parallel, and the hands-off reference channel 80 includes a second resistor R2 801 and a second capacitor C2 802 connected in parallel.

[0036] The first switch tube 40 is a P-type metal oxide semiconductor (PMetal-Oxide-Semiconductor Field-Effect Transistor, PMOS), and the second switch tube 50 and the third switch tube 60 are N-type metal oxide semiconductors (NMetal-Oxide-Semiconductor Field-Effect Transistor, NMOS). In addition, the second switch tube 50 and the third switch tube 60 have different turn-on voltages and different turn-off voltages. In actual situations, the turn-on voltages of the second switch tube 50 and the third switch tube 60 can be set as needed.

[0037] Optionally, the acquisition unit 20 is a non-contact capacitive sensor. Also, the acquisition unit 20 is provided with a Single Edge Nibble Transmission (SEN) channel.

[0038] For example, in the above detection circuit, the acquisition unit 20-actual hand-off channel 70-heating unit 10-forms a first path. The acquisition unit 20-actual hand-off channel 70-second switch tube 50-hand-off reference channel 80-forms a second path. The power supply 90-first switch tube 40-heating unit-forms a third path.

[0039] Optionally, in actual situations, the acquisition unit 20 is a non-contact capacitance sensor, which establishes a voltage on the load (steering wheel and human hand) being measured by emitting a sine wave to the object being measured. Also, the detector inside the non-contact sensor receives the mirror current fed back from the load end, and processes the mirror current through the built-in circuit device to obtain the hand-grip detection data of the detection circuit and the reference circuit. That is, after the acquisition unit 2 sends the sine wave through the first path and the second path, it obtains the hand-grip detection data of the detection circuit and the reference circuit by detecting the impedance change between the steering wheel and the hand.

[0040] The detection circuit provided in the embodiment of the present invention uses an added hands-off reference channel to provide a hands-off reference circuit for the entire detection circuit, thereby solving the problem that the detection circuit may have a large error when detecting the hands-off state of the steering wheel due to the presence of a large parasitic capacitance caused by the use of a switching tube. The added hands-off reference channel is used to provide a control group circuit for reference and comparison when detecting the hands-off state of the steering wheel.

[0041] Figure 3 The flowchart of a steering wheel detection method provided in an embodiment of the present invention is applicable to any of the above embodiments and other optional embodiments. The steering wheel detection method provided in an embodiment of the present invention can be applied to a control unit. In this embodiment, the control unit can be a master controller in a vehicle. Alternatively, it can also be a hand-on / off detection controller in a vehicle that is connected to the master controller. Figure 3 Before describing the steering wheel detection method, a brief introduction is first given to the current vehicle steering wheel hands-on and hands-off detection methods.

[0042] The existing steering wheel is provided with a heating device, which is used to provide the driver with a steering wheel heating function when the steering wheel temperature is low. In order to ensure the driver's safety during driving, a hand-on detection device is also provided on the steering wheel to determine the driver's hand-off state. Therefore, in general, the steering wheel is not only provided with a heating device, but also a hand-on detection device. However, in the actual hand-on detection process, the heating device of the steering wheel or the capacitor in the hand-on detection circuit is heated by the ambient temperature, which will cause a large error in the final result of the hand-on detection. Therefore, how to solve the problem that in the hand-on detection process, the detection result will not produce errors due to the capacitor in the circuit being affected by the ambient temperature or not being affected by the heating of the steering wheel is a problem to be solved by the method provided by the present invention.

[0043] Continue to refer Figure 3 .like Figure 3 As shown, the method includes:

[0044] S301. The control unit controls the first switch tube, the second switch tube and the third switch tube to be turned off, and sends a first acquisition command to the acquisition unit to obtain the hand-off detection data of the actual hand-off channel acquired by the acquisition unit.

[0045] The first acquisition command is used to start the acquisition unit to collect the hands-off detection data of the actual hands-off channel.

[0046] Specifically, the control unit continuously initiates different levels to the first switch tube, the second switch tube, and the third switch tube through different interfaces, so that the drain D and the source S of the first switch tube, the second switch tube, and the third switch tube cannot be turned on. In addition, a first acquisition command is sent to the acquisition unit, so that the acquisition unit acquires the hand-off detection data after passing through the actual hand-off channel.

[0047] Exemplarily, the control unit continuously sends a high-level signal to the first switch tube through the pin1 interface, so that the drain D and source S of the first switch tube cannot be turned on. At this time, the power supply cannot supply power to the heating unit, so the steering wheel is in a non-heating state at this time. In addition, the control unit continuously sends different preset low-level signals to the second switch tube and the third switch tube through the pin2 interface and the pin3 interface, respectively, so that the drain D and source S of the second switch tube and the third switch tube cannot be turned on. At this time, the circuit leading to the hand-off reference channel is disconnected. And, the control unit sends a first acquisition command to the acquisition unit, and when the acquisition unit receives the first acquisition command, it turns on the SEN detection channel and emits a sine wave to the actual hand-off channel. Due to the principle of electromagnetic induction, a voltage is formed on the actual hand-off channel (i.e., the first path), so that there is a voltage on the load similar to a capacitor composed of the steering wheel and the hand. At this time, the detector inside the acquisition unit will receive the mirror current fed back from the load end, and obtain the hand-off detection data after being processed by the circuit device inside the acquisition unit.

[0048] In this embodiment, the first switch tube is used to disconnect the circuit between the power supply and the heating unit, so that the power supply cannot supply power to the heating unit, so that the heating power supply cannot heat the steering wheel. At this time, the hand-off detection data at the actual hand-off channel is collected, which solves the problem that the hand-off detection data will have errors due to the heating of the steering wheel, and eliminates the influence of the steering wheel heating on the hand-off detection data when collecting the hand-off detection data, thereby ensuring the accuracy of the hand-off detection data.

[0049] S302: The control unit controls the first switch tube and the third switch tube to be turned off, controls the second switch tube to be turned on, and sends a second acquisition command to the acquisition unit to obtain the hand-off reference data of the hand-off reference channel and the hand-off actual channel acquired by the acquisition unit.

[0050] The second acquisition command is used to start the acquisition unit to collect the hand-off reference data of the hand-off reference channel and the hand-off actual channel.

[0051] Specifically, the control unit continuously initiates different levels to the first switch tube, the second switch tube, and the third switch tube through different interfaces, so that the drain D and the source S of the first switch tube and the third switch tube cannot be turned on, and the drain D and the source S of the second switch tube are turned on. And, the second acquisition command is sent to the acquisition unit, and at this time, the acquisition unit can obtain the hand-off reference data of the hand-off reference channel and the hand-off actual channel.

[0052] Exemplarily, the control unit continuously sends a high-level signal to the first switch tube through the pin1 interface, so that the drain D and source S of the first switch tube cannot be turned on. At this time, the power supply cannot supply power to the heating unit, and the steering wheel is in a non-heating state. In addition, the control unit continuously sends a high-level signal to the second switch tube through the pin2 interface, so that the drain D and source S of the second switch tube are turned on. At this time, the circuit of the hand-off reference channel can be turned on. Among them, the turn-on voltage of the high-level signal sent by the control unit to the first switch tube and the second switch tube is different, which can be determined according to the user's pre-setting. And, the control unit continuously sends a low-level signal to the third switch tube through the pin3 interface, so that the drain D and source S of the third switch tube cannot be turned on. And, the control unit sends a second acquisition command to the acquisition unit, and when the acquisition unit receives the second acquisition command, it turns on the SEN detection channel and emits a sine wave to the actual hand-off channel. Due to the principle of electromagnetic induction, a voltage is formed on the path (i.e., the second path) between the actual hand-off channel and the hand-off reference channel, so that a voltage exists on the load similar to a capacitor composed of the steering wheel and the hand. At this time, the detector inside the acquisition unit will receive the mirror current fed back from the load end, and obtain the hands-off reference data after being processed by the circuit devices inside the acquisition unit.

[0053] In this embodiment, the second switch tube is used to conduct the circuit leading to the hand-off reference channel, so that the acquisition unit can acquire the hand-off reference data of the hand-off actual channel and the hand-off reference channel.

[0054] S303: The control unit determines the hand-off state of the steering wheel of the vehicle according to the hand-off detection data, the hand-off reference data and the preset hand-off threshold.

[0055] The preset hand-grip threshold is a preset threshold of hand-off detection data.

[0056] Specifically, the control unit receives the hand-off detection data and the hand-off reference data collected and transmitted by the collection unit, and processes the hand-off detection data and the hand-off reference data. After the processing, the actual hand-holding value can be obtained, and the actual hand-holding value is compared with the preset hand-holding threshold value. If the actual hand-holding value is greater than the preset hand-holding threshold value, the hand-holding and hand-off state is the hand-holding state; if the actual hand-holding value is less than or equal to the preset hand-holding threshold value, the hand-holding and hand-off state is the hand-off state.

[0057] Exemplarily, the hand-off detection data collects the target sine wave after the original sine wave passes through the actual hand-off channel, that is, the hand-off detection data corresponding to the actual hand-off channel is the hand-holding and hand-off state value plus the influence value of the hand-holding and hand-off state value of the capacitor caused by the ambient temperature. The hand-off reference data collects the target sine wave after the original sine wave passes through the actual hand-off channel and the hand-off reference channel, that is, the hand-off reference data corresponding to the actual hand-off channel is the hand-holding and hand-off state value, the reference hand-holding and hand-off state value plus the influence value of the hand-holding and hand-off state value of the capacitor caused by the ambient temperature. Therefore, the hand-off reference data can be subtracted from the actual hand-off data to obtain the actual hand-holding value that cancels the influence value of the hand-holding and hand-off state value of the capacitor caused by the ambient temperature and only leaves the hand-holding and hand-off state value.

[0058] In this embodiment, the "influence value of the capacitance on the hand-gripping and hand-off state value caused by the ambient temperature" in the hand-gripping reference data can be offset with the "influence value of the capacitance on the hand-gripping and hand-off state value caused by the ambient temperature" in the hand-gripping detection data. Therefore, the influence value of the hand-gripping and hand-off state value caused by the ambient temperature on the capacitance can be offset according to the hand-gripping reference data and the hand-gripping detection data, thereby solving the problem of error in the hand-gripping and hand-off state detection caused by the circuit capacitance being affected by the ambient temperature, and achieving accurate calculation of the actual hand-gripping value corresponding to the hand-gripping and hand-off detection state.

[0059] Optionally, the steering wheel detection method provided in the embodiment of the present invention can be further added based on the above embodiment. Figure 4 Follow the steps shown in . Figure 4 FIG. 1 is a flow chart of another steering wheel detection method provided by an embodiment of the present invention. Figure 4 As shown, the method includes:

[0060] S401. The control unit controls the first switch tube, the second switch tube and the third switch tube to be turned off, and sends a first acquisition command to the acquisition unit to obtain the hand-off detection data of the actual hand-off channel acquired by the acquisition unit.

[0061] Specifically, the control unit continuously initiates different levels to the first switch tube, the second switch tube, and the third switch tube through different interfaces, so that the drain D and the source S of the first switch tube, the second switch tube, and the third switch tube cannot be turned on. In addition, a first acquisition command is sent to the acquisition unit, so that the acquisition unit acquires the hand-off detection data after passing through the actual hand-off channel.

[0062] S402: The control unit controls the first switch tube and the third switch tube to be turned off, controls the second switch tube to be turned on, and sends a second acquisition command to the acquisition unit to obtain the hand-off reference data of the hand-off reference channel and the hand-off actual channel acquired by the acquisition unit.

[0063] Specifically, the control unit continuously initiates different levels to the first switch tube, the second switch tube, and the third switch tube through different interfaces, so that the drain D and the source S of the first switch tube and the third switch tube cannot be turned on, and the drain D and the source S of the second switch tube are turned on. And, the second acquisition command is sent to the acquisition unit, and at this time, the acquisition unit can obtain the hand-off reference data of the hand-off reference channel and the hand-off actual channel.

[0064] S403, determine whether the current temperature of the steering wheel is less than the target temperature; if so, execute S404; if not, execute S405.

[0065] The target temperature is the maximum allowable temperature for heating the steering wheel set in advance by the user.

[0066] Specifically, after the acquisition unit obtains the hand-off detection data and the hand-off reference data, the control unit needs to determine whether the current temperature of the steering wheel is less than the target temperature. If the current temperature is less than the target temperature, S404 can be directly executed. If the current temperature is greater than or equal to the target temperature, it means that the current temperature of the steering wheel has reached or exceeded the maximum allowable temperature for heating the steering wheel, and therefore, the steering wheel does not need to be heated to save power, and S405 is directly executed.

[0067] Optionally, before determining whether the current temperature of the steering wheel is less than the target temperature, it may be determined whether the control unit has received a heating instruction initiated by the user. If a heating instruction initiated by the user is received, it continues to determine whether the current temperature of the steering wheel is less than the target temperature. If the control unit has not received a heating instruction from the user, S405 may be directly executed.

[0068] S404: The control unit controls the first switch tube, the second switch tube, and the third switch tube to be turned on, and the vehicle power supply supplies power to the heating unit to heat the steering wheel.

[0069] Specifically, if the current temperature of the steering wheel is lower than the target temperature, the control unit can control the first switch tube, the second switch tube and the third switch tube to be turned on. At this time, the circuit between the power supply and the heating unit is turned on, and the power supply supplies power to the heating unit, so that the heating unit heats the steering wheel.

[0070] Exemplarily, the control unit initiates a low-level signal to the first switch tube through the pin1 interface to conduct the drain D and source S of the first switch tube. At this time, the circuit between the power supply and the heating unit is conducted, and the power supply supplies power to the heating unit so that the heating unit heats the steering wheel. At the same time, the control unit initiates different low-level signals to the second switch tube and the third switch tube through the pin2 interface and the pin3 interface, respectively, to conduct the drain D and source S of the second switch tube and the third switch tube, respectively. At this time, the actual hand-off channel and the hand-off reference channel are short-circuited. Among them, the second switch tube is grounded.

[0071] Optionally, the control unit sends a shutdown control instruction to the collection unit, and the collection unit stops collecting data when receiving the shutdown control instruction.

[0072] In this embodiment, by determining whether the current temperature of the steering wheel is greater than the target temperature, it is possible to determine whether the steering wheel still needs to be heated. This ensures that the steering wheel will not be overheated and waste electric energy, while ensuring that the driver's driving experience will not be reduced due to overheating of the steering wheel.

[0073] S405: Determine actual hand-off detection data according to the hand-off detection data and the hand-off reference data.

[0074] Specifically, if the current temperature of the steering wheel exceeds the target temperature, or when controlling the steering wheel heating, the control unit may determine the hand-off detection actual data according to the hand-off detection data and the hand-off reference data.

[0075] For example, since the hand-off detection data and the hand-off reference data are essentially sinusoidal data, the acquisition unit can obtain the in-phase data amount I and the quadrature data amount Q reflecting the amplitude and phase of the sinusoidal data after processing the acquired sinusoidal data. That is, after the acquisition unit sends the processed data to the control unit, the hand-off detection data obtained by the control unit is "the in-phase data amount I and the quadrature data amount Q". 检测 ” and “Detection of orthogonal data volume Q 检测 ". The hands-off reference data obtained by the control unit is the "reference in-phase data amount I 参考 " and "reference orthogonal data volume Q 参考 ”.

[0076] After that, the actual data of hand-off detection can be calculated according to the following formula:

[0077] I 实际 =I参考 -I 检测 ;

[0078] Q 实际 =Q 参考 -Q 检测 ;

[0079]

[0080] Among them, I 实际 It is the amount of in-phase data of the actual data of the hand-off detection. 实际 is the amount of orthogonal data for the actual hand-off detection data. 实际 Actual data for hand-off detection.

[0081] S406, determining whether the actual data of the hands-off detection is greater than a preset hand-holding threshold; if so, executing S408; if not, executing S407.

[0082] The preset hand grip threshold may be pre-set by a user, or may be a hand grip threshold calibrated during a test or experiment.

[0083] Specifically, after the actual data of the hand-off detection is calculated, the actual data of the hand-off detection can be compared with the preset hand-holding threshold. If the actual data of the hand-off detection is greater than the preset hand-holding threshold, S408 can be executed. If the actual data of the hand-off detection is not greater than the preset hand-holding threshold, S407 can be executed.

[0084] S407: Determine whether the hand-on / off state of the steering wheel is a hand-off state.

[0085] Specifically, if the actual data of the hand-off detection of the steering wheel is not greater than the preset hand-holding threshold, it means that the hand-off state of the steering wheel is currently the hand-off state, that is, the driver's hands are not on the steering wheel.

[0086] S408: Determine whether the hands-off state of the steering wheel is the hands-on state.

[0087] Specifically, if the actual data of the hand-off detection of the steering wheel is greater than the preset hand-holding threshold, it means that the hand-off state of the steering wheel is currently the hand-holding state, that is, the driver's hands are placed on the steering wheel and are holding the steering wheel.

[0088] Optionally, after determining that the hand-on / off state of the steering wheel is the hand-on state, the method further includes:

[0089] Return to execute S401, and continue to determine the next actual data of hand-off detection. And, when determining the next actual data of hand-off detection, obtain the correction coefficient, and update the preset hand-holding threshold according to the correction coefficient, wherein the updated preset hand-holding threshold is less than the preset hand-holding threshold before updating. That is, when determining the next actual data of hand-off detection, it is necessary to use the correction coefficient to correct the preset hand-holding threshold to obtain the updated preset hand-holding threshold, and compare the next actual data of hand-off detection with the updated preset hand-holding threshold to determine the hand-holding and hand-off state of the steering wheel.

[0090] Exemplarily, when the vehicle is powered on, the hand-on / off state of the steering wheel is the hand-off state. When the method provided by the embodiment of the present invention is executed for the first time, after executing from S401 to S406, if it is determined that the hand-on / off state of the steering wheel is the hand-off state, then continue to return to execute S401. If it is determined that the hand-on / off state of the steering wheel is the hand-on state, then continue to return to execute S401 until S405 is executed and the actual data of the second hand-off detection is determined. At this time, it is necessary to obtain a correction coefficient, and update the preset hand-on threshold according to the correction coefficient to obtain the updated preset hand-on threshold. The hand-on / off state of the steering wheel in the second hand-off detection is determined based on the actual data of the second hand-off detection and the updated preset hand-on threshold. If it is still the hand-on state, when returning to execute the method provided by the embodiment of the present invention for the third time, the correction coefficient is used again to update the updated preset hand-on threshold. If it is the hand-off state, then the third return execution uses the original preset hand-on threshold for judgment. Among them, the correction coefficient can be a number between 0 and 1. Optionally, the correction coefficient is 0.8.

[0091] Optionally, in the above scheme, it takes about 8ms to collect the hand-off detection data and the hand-off reference data, and 40ms to heat. The detection circuit and steering wheel detection method provided in the embodiment of the present invention can ensure the efficiency of heating and the sensitivity of hand-off detection. The collected hand-off detection data of the detection circuit and the hand-off reference data of the reference circuit are subtracted as the final data for judging the hand-off detection, which can eliminate the influence of ambient temperature and steering wheel heating on the hand-off detection and will not lead to misjudgment of the hand-off state. This method mainly uses another set of data that is also affected by ambient temperature and heating to do the elimination, and ensures that the changes affected by ambient temperature and heating are consistent with the changes of the hand-off detection circuit.

[0092] In this embodiment, each time the hand-on / off state of the steering wheel is determined to be the hand-on state, the preset hand-on threshold is corrected using the correction coefficient, so that the hand-on / off judgment of the steering wheel in the hand-on state can be more accurate.

[0093] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0094] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0095] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in combination with an instruction execution system, device or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0096] To provide interaction with a user, the systems and techniques described herein may be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0097] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0098] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the respective computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0099] An embodiment of the present invention further provides a computer program product, including a computer program, which, when executed by a processor, implements the steering wheel detection method provided by any embodiment of the present invention.

[0100] In the process of implementation, the computer program product can be written in one or more programming languages ​​or a combination thereof to perform the computer program code of the present invention, including object-oriented programming languages, such as Java, Smalltalk, C++, and conventional procedural programming languages, such as "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computer (for example, using an Internet service provider to connect through the Internet).

[0101] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0102] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A detection circuit, characterized in that: include: Heating unit, collection unit, control unit, first switch tube, second switch tube, third switch tube, hands-off actual channel and hands-off reference channel; wherein, The heating unit is arranged in the steering wheel of the vehicle, and the steering wheel is grounded; the source of the first switch tube is electrically connected to one end of the heating unit, the drain of the first switch tube is externally connected to the vehicle power supply, and the gate of the first switch tube is electrically connected to the first pin of the control unit; the other end of the heating unit is electrically connected to one end of the hands-off actual channel, and the other end of the hands-off actual channel is electrically connected to the acquisition unit; The second pin of the control unit is electrically connected to the gate of the second switch tube, the third pin of the control unit is electrically connected to the gate of the third switch tube, the drain of the second switch tube is electrically connected to the other end of the heating unit, and the source of the second switch tube is electrically connected to the drain of the third switch tube and one end of the hand-off reference channel respectively; the source of the third switch tube and the other end of the hand-off reference channel are both grounded; The control unit is in communication connection with the acquisition unit.

2. The detection circuit according to claim 1, characterized in that: The hands-off actual channel includes a first resistor and a first capacitor connected in parallel, and the hands-off reference channel includes a second resistor and a second capacitor connected in parallel.

3. The detection circuit according to claim 1, characterized in that: The first switch tube is a P-type metal oxide semiconductor, and the second switch tube and the third switch tube are N-type metal oxide semiconductors; The acquisition unit is a non-contact capacitive sensor.

4. The detection circuit according to claim 1, characterized in that: The turn-on voltages of the second switch tube and the third switch tube are different.

5. A steering wheel detection method, characterized in that: The steering wheel detection method is applied to the detection circuit as described in any one of claims 1 to 4; the method comprises: The control unit controls the first switch tube, the second switch tube and the third switch tube to be turned off, and sends a first acquisition command to the acquisition unit to obtain the hand-off detection data of the actual hand-off channel acquired by the acquisition unit; The control unit controls the first switch tube and the third switch tube to be turned off, controls the second switch tube to be turned on, and sends a second acquisition command to the acquisition unit to obtain the hand-off reference data of the hand-off reference channel and the hand-off actual channel acquired by the acquisition unit; The control unit determines a hand-on / off state of a steering wheel of a vehicle according to the hand-off detection data, the hand-off reference data and a preset hand-off threshold.

6. The steering wheel detection method according to claim 5, characterized in that: Before the control unit determines the hand-on / off state of the steering wheel of the vehicle according to the hand-off detection data, the hand-off reference data and a preset hand-off threshold, the method further includes: determining whether the current temperature of the steering wheel is less than a target temperature; If the current temperature of the steering wheel is lower than the target temperature, the control unit controls the first switch tube, the second switch tube and the third switch tube to be turned on, and the vehicle power supply supplies power to the heating unit to heat the steering wheel.

7. The steering wheel detection method according to claim 5, characterized in that: The control unit determines the hand-on / off state of the steering wheel of the vehicle according to the hand-off detection data, the hand-off reference data and a preset hand-off threshold, including: Determine actual hand-off detection data according to the hand-off detection data and the hand-off reference data; If the actual data of the hand-off detection is greater than the preset hand-holding threshold, determining that the hand-off state of the steering wheel is a hand-holding state; If the actual hand-off detection data is less than or equal to the preset hand-off threshold, it is determined that the hand-off state of the steering wheel is a hand-off state.

8. The steering wheel detection method according to claim 7, characterized in that: After determining that the hand-on / off state of the steering wheel is the hand-on state, the method further includes: Get the correction factor; The preset hand-gripping threshold is updated according to the correction coefficient, wherein the updated preset hand-gripping threshold is smaller than the preset hand-gripping threshold before the update.

9. A readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steering wheel detection method according to any one of claims 5 to 8 is implemented.

10. A computer program product, characterized in that include: A computer program, wherein when the computer program is executed by a processor, the computer program implements the steering wheel detection method according to any one of claims 5 to 8.

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