Detection device, method and vehicle for steering wheel hands-off detection

Abstract

The application discloses a detection device, method and vehicle for steering wheel hand-off detection, and belongs to the technical field of vehicle control. The device comprises: a hand-off detection unit; an open circuit detection unit; a metal wire assembly, a first end of the metal wire assembly being connected to an excitation output end of the hand-off detection unit, a second end of the metal wire assembly being connected to a signal receiving end of the hand-off detection unit; the open circuit detection unit being connected to the signal receiving end of the hand-off detection unit; and a master control unit connected to the hand-off detection unit and the open circuit detection unit and configured to enable the hand-off detection unit and / or the open circuit detection unit to perform steering wheel hand-off detection and / or metal wire open circuit detection operation in response to mode regulation instructions. The application can switch between the steering wheel hand-off detection mode and the metal wire open circuit detection mode, and can accurately detect open circuit or fracture failure of the metal wire assembly.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, specifically to a detection device, method, and vehicle for detecting when the steering wheel is removed from the hands. Background Technology

[0002] As the level of intelligent driver assistance systems in automobiles continues to improve, hands-off detection (HOD) has become an essential function to ensure the safety of human-machine co-driving. Currently, the industry generally adopts a capacitive detection solution, which uses metal wires as sensing electrodes inside the steering wheel. The hands-off detection unit applies an excitation waveform to the metal wires, and determines whether the driver is holding the steering wheel based on the capacitance change caused by hand contact.

[0003] In related steering wheel hands-off detection devices, the steering wheel wire usually adopts a circuit structure in which one end is connected to the detection unit and the other end is suspended. Although this circuit structure can realize steering wheel hands-off detection, when the internal wire becomes open-circuited or broken due to vibration, aging, assembly errors or other reasons, it cannot identify whether the wire has failed, which can easily lead to misjudgment or failure of the hands-off detection function. Summary of the Invention

[0004] A detection device, method, and vehicle for detecting steering wheel hands-off are provided, aiming to solve the problem that related capacitive steering wheel hands-off detection devices cannot identify whether the metal wire is open-circuited or broken, thus causing misjudgment or failure of the hands-off detection function.

[0005] In a first aspect, a detection device for detecting when a steering wheel is removed from hands is provided, comprising: Hand-off detection unit; Open circuit detection unit; A metal wire assembly, wherein a first end of the metal wire assembly is connected to the excitation output terminal of the off-hand detection unit, and a second end of the metal wire assembly is connected to the signal receiving terminal of the off-hand detection unit; the open-circuit detection unit is connected to the signal receiving terminal of the off-hand detection unit. The main control unit, connected to the hands-off detection unit and the open-circuit detection unit, is configured to activate the hands-off detection unit and / or the open-circuit detection unit in response to a mode control command, so as to perform steering wheel hands-off detection and / or wire open-circuit detection operations.

[0006] Optionally, the device further includes a switch assembly, wherein the second end of the wire assembly is connected to the signal receiving end of the off-hand detection unit via the switch assembly; The main control unit is connected to the hands-off detection unit and the switch assembly respectively, and is configured to control the switch assembly to turn on and off in response to the mode control command, so as to perform the steering wheel hands-off detection or the wire open circuit detection operation.

[0007] Optional, The switching assembly includes a first switch; The metal wire assembly includes a first metal wire; The first end of the first metal wire is connected to the excitation output terminal of the off-hand detection unit, and the second end of the first metal wire is connected to the signal receiving terminal of the off-hand detection unit via the first switch.

[0008] Optionally, the device may further include a heating control unit; The wire assembly includes a second wire; The first end of the second metal wire is connected to the heating control unit, and the second end of the second metal wire is grounded.

[0009] Optionally, the device may further include a heating control unit; The switching assembly further includes a second switch and a third switch; The heating control unit is connected to either the first or second end of the first metal wire via the second switch; The end of the first metal wire furthest from the second switch is grounded through the third switch.

[0010] Optionally, the device may further include an external communication unit; The external communication unit is connected to the main control unit and is configured to receive the mode control command and transmit the mode control command to the main control unit.

[0011] Secondly, a detection method for detecting steering wheel hands-off is also provided, applied to the detection device for detecting steering wheel hands-off as described in any of the above claims, the method comprising the following steps: In response to the mode control command, the hands-off detection unit and / or the open circuit detection unit are activated to perform steering wheel hands-off detection and / or wire open circuit detection operations.

[0012] Optionally, the device further includes a switching assembly, the switching assembly including a first switch; The method further includes: In response to the mode control command, the first switch is turned on to activate the open circuit detection mode for the metal wire.

[0013] Optionally, the device may further include a heating control unit and a switching assembly; The switching assembly includes a second switch and a third switch; The heating control unit is connected to either the first or second end of the first metal wire via the second switch; The end of the first metal wire furthest from the second switch is grounded through the third switch; The method further includes: In response to the mode control command, the second switch and the third switch are turned on, and the heating control unit is controlled to output a drive signal to turn on the steering wheel heating mode.

[0014] Optionally, the method further includes: In response to the mode control command, the second switch, the third switch, and the heating control unit are disconnected, and the steering wheel off-hand detection mode is activated.

[0015] Thirdly, a vehicle is also provided, comprising: Steering wheel; and, The detection device for detecting steering wheel removal as described above, and the device is used to perform the steps of the detection method for detecting steering wheel removal as described above.

[0016] Beneficial effects: This application connects the two ends of the metal wire assembly to the excitation output and signal receiving ends of the hands-off detection unit, respectively, and sets up a switching component controlled by the main control unit. This enables the switching between the steering wheel hands-off detection mode and the metal wire open circuit detection mode. Without affecting the accuracy of the original capacitive hands-off detection function, no additional detection hardware is required. With only simple circuit modification, the open circuit or breakage fault of the metal wire assembly can be accurately detected, thereby effectively improving the reliability and safety of the steering wheel hands-off detection system and effectively controlling hardware costs and wiring complexity. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a detection device for detecting when a steering wheel is removed from hands, provided by an exemplary embodiment of this disclosure; Figure 2 This is a schematic diagram of another detection device for detecting when the steering wheel is removed from the hands, provided by an exemplary embodiment of this disclosure; Figure 3 This is a schematic diagram of another detection device for detecting when the steering wheel is removed from the hands, provided by an exemplary embodiment of this disclosure; Figure 4 This is a schematic diagram of another detection device for detecting when the steering wheel is removed from the hands, provided by an exemplary embodiment of this disclosure; Figure 5This is a schematic flowchart of a detection method for detecting when the steering wheel is removed from the hands, provided by an exemplary embodiment of this disclosure. Figure 6 This is an exemplary embodiment provided by the present disclosure. Figure 3 A schematic diagram of the internal circuit structure of the corresponding open-circuit detection device for metal wires; Figure 7 This is an exemplary embodiment provided by the present disclosure. Figure 4 A schematic diagram of the internal circuit structure of the corresponding open-circuit detection device for metal wires.

[0019] Figure label: 10. Steering wheel end; 11. First metal wire; 12. Second metal wire; 13. Third metal wire; 20. Single board end; 21. MCU control unit; 22. Hand-off detection unit; 23. Heating control unit; 24. First switch; 25. Second switch; 26. Third switch. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0021] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to has a specific orientation, or is constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0022] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0023] The use of "applies to" or "configured to" in this application implies open and inclusive language, which does not exclude the applicability to or configuration to devices performing additional tasks or steps. Additionally, the use of "based on" implies openness and inclusivity, because processes, steps, calculations, or other actions "based on" one or more of the stated conditions or values ​​may in practice be based on additional conditions or values ​​beyond those stated.

[0024] In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes are not described in detail to avoid obscuring the description of this application with unnecessary detail. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0025] On one hand, this embodiment provides a detection device for detecting when the steering wheel is removed from the hands; please refer to [link / reference]. Figure 1 It includes: an open circuit detection unit, a hands-free detection unit, a metal wire assembly, and a main control unit. The structure and function of each unit in the metal wire open circuit detection device are as follows: The first end of the metal wire assembly is connected to the excitation output terminal of the off-hand detection unit, and the second end of the metal wire assembly is connected to the signal receiving terminal of the off-hand detection unit; the open-circuit detection unit is connected to the signal receiving terminal of the off-hand detection unit. The main control unit, connected to the hands-off detection unit and the open-circuit detection unit, is configured to activate the hands-off detection unit and / or the open-circuit detection unit in response to a mode control command, to perform steering wheel hands-off detection and / or wire open-circuit detection operations. Optionally, the main control unit, in response to a mode control command, performs steering wheel hands-off detection operation when the hands-off detection unit is activated; performs wire open-circuit detection operation when the open-circuit detection unit is activated; and performs both steering wheel hands-off detection and wire open-circuit detection operations simultaneously when both are activated.

[0026] For example, the hands-off detection unit is a detection chip or circuit module with waveform excitation output and signal reception detection capabilities, including an excitation output terminal for excitation output and a signal receiving terminal for signal reception. The open-circuit detection unit is a detection chip or circuit module with at least signal reception detection capabilities. The excitation output terminal of the hands-off detection unit outputs continuous excitation waveforms such as sine waves and square waves to the wire assembly to establish a capacitive sensing detection field. The signal receiving terminal of the hands-off detection unit receives the excitation signal returning through the wire assembly and determines whether the hand has moved away from the steering wheel based on parameters such as signal amplitude and waveform changes. The open-circuit detection unit determines the continuity of the wire based on whether the returning excitation signal disappears; if there is no returning signal, the wire may be broken. These two ports enable the hands-off detection unit and the open-circuit detection unit to have dual signal processing capabilities: capacitive hands-off detection and excitation signal return detection. In some embodiments, the hands-off detection unit and the open-circuit detection unit can also be integrated into the same chip or circuit module.

[0027] The wire assembly, a conductive metal wire or metal film sensing component installed inside the steering wheel, serves as the execution carrier for hands-off detection and open-circuit detection. The first end of the wire assembly is connected to the excitation output of the hands-off detection unit, and the second end is connected to the signal receiving ends of both the hands-off detection unit and the open-circuit detection unit. In the hands-off detection mode, it acts as a capacitive sensing electrode, feeding back the capacitance change caused by hand contact to the hands-off detection unit. In the open-circuit detection mode, it serves as an excitation signal transmission path, ensuring the waveform is transmitted from the first end to the second end, providing a physical link for determining the continuity of the wire. It is easy to understand that this embodiment does not specifically distinguish between the first and second ends of the wire assembly, but rather refers to both ends of the wire assembly in general.

[0028] The main control unit is the MCU (Microcontroller Unit) control unit in the vehicle or steering wheel domain, electrically connected to the hands-off detection unit and the open-circuit detection unit, respectively. The main control unit is configured to receive mode control commands, control the excitation output of the hands-off detection unit according to the mode control commands, and control the signal receiving terminals of the hands-off detection unit and the open-circuit detection unit to analyze and judge the return current signal, identify whether there is an open circuit or breakage fault in the wire assembly, and output the detection results and fault information to the vehicle controller or host computer, realizing the steering wheel hands-off detection or wire open-circuit detection operation.

[0029] In some embodiments, please refer to Figure 2A switch assembly is installed between the metal wire assembly and the hands-off detection unit and open-circuit detection unit, and the switch assembly is connected to the main control unit. The switch assembly reduces interference between the two signal terminals when the switch assembly is disconnected in the hands-off detection mode, resulting in stronger signal anti-interference capability and improved detection accuracy. By connecting the two ends of the metal wire assembly to the excitation output terminal and signal receiving terminal of the hands-off detection unit respectively, and setting a switch assembly controlled by the main control unit, switching between the hands-off detection mode and the metal wire open-circuit detection mode can be achieved. Without affecting the accuracy of the original capacitive hands-off detection function, no additional detection hardware is required; only simple circuit modifications are needed to accurately detect open-circuit or broken faults in the metal wire assembly. This effectively improves the reliability and safety of the steering wheel hands-off detection system and effectively controls hardware costs and wiring complexity.

[0030] The switching assembly is an electrically controlled switch unit, which can employ devices with on / off control capabilities such as MOSFETs, relays, or analog switches. The input terminal of the switching assembly is connected to the second terminal of the wire assembly, the output terminal is connected to the signal receiving terminal of the hands-off detection unit, and the control terminal is electrically connected to the main control unit. Specifically, the control terminal of the switching assembly is the terminal that receives control signals from the main control unit. It is used to control the internal conduction or cutoff of the switching assembly according to the mode control commands output by the main control unit, thereby switching the electrical path between the wire assembly and the signal receiving terminal of the hands-off detection unit. The function of the switching assembly is to control the on / off electrical link between the wire assembly and the signal receiving terminal of the hands-off detection unit, and under the mode control commands of the main control unit, to realize the hardware link switching between the steering wheel hands-off detection mode and the wire open-circuit detection mode.

[0031] In some embodiments, the switch assembly includes a first switch, which is a controllable electronic switch directly controlled by the main control unit. Its on / off state is regulated by the main control unit according to mode control commands. The wire assembly includes a first metal wire. The first metal wire is a sensing metal wire within the steering wheel used to implement the hands-off detection function. Optionally, the first end of the first metal wire is connected to the excitation output terminal of the hands-off detection unit, and the second end of the first metal wire is no longer conventionally suspended, but is connected to the signal receiving terminal of the hands-off detection unit via the first switch, forming a closed-loop detection link that can be controlled by the first switch.

[0032] For example, in the steering wheel hands-off detection mode, the main control unit controls the first switch to be in the off state, electrically disconnecting the second end of the first metal wire from the signal receiving end of the hands-off detection unit. This restores the first metal wire to a single-ended excitation, near-suspended working state. The hands-off detection unit outputs an excitation waveform through the first end, detecting the driver's grip state based on the capacitance change between the first metal wire and the human body. In the metal wire open-circuit detection mode, the main control unit controls the first switch to be in the conducting state, electrically connecting the second end of the first metal wire to the signal receiving end of the hands-off detection unit. The excitation waveform output by the first end of the hands-off detection unit can be transmitted to the signal receiving end of the hands-off detection unit via the first metal wire and the first switch. If the signal receiving end of the hands-off detection unit can normally receive the excitation waveform, it is determined that the first metal wire path is intact; if the signal receiving end of the hands-off detection unit cannot receive the excitation waveform, it is determined that the first metal wire has an open-circuit or broken fault, thus realizing the detection of open-circuit faults in the hands-off detection metal wire.

[0033] This embodiment, through a hardware structure of a single metal wire and a single switch, adds the capability of detecting open circuits in the metal wire without changing the original off-hand detection function. It is suitable for steering wheel system architectures where the off-hand detection metal wire and the heating metal wire are independent. It features minimal circuit modification, low implementation cost, and stable and reliable operation.

[0034] In some embodiments, the device further includes a heating control unit.

[0035] The wire assembly includes a first wire and a second wire. The first wire is used for hands-off detection and open-circuit detection, while the second wire is used for heating the steering wheel. The first end of the first wire is connected to the excitation output of the hands-off detection unit, and the second end is connected to the signal receiving end of the hands-off detection unit via a first switch. The first end of the second wire is electrically connected to the output of the heating control unit, and the second end is connected to a common ground terminal (GND), forming an independent steering wheel heating drive circuit.

[0036] Under the control of the main control unit, the heating control unit provides drive current and power output to the second metal wire, so that the second metal wire generates heat to meet the steering wheel heating requirements. At the same time, the heating control unit can detect circuit current, voltage and other parameters to diagnose faults such as short circuit and open circuit of the second metal wire, and feed back the diagnosis results to the main control unit.

[0037] In this embodiment, the hands-off detection and open-circuit detection circuit formed by the first metal wire and the first switch, and the heating circuit formed by the second metal wire and the heating control unit work independently. This ensures the normal operation of the steering wheel hands-off detection and heating functions, and also allows for fault detection of the first and second metal wires, thereby improving the overall functional reliability and safety of the device.

[0038] In some embodiments, the device further includes a heating control unit; the switching assembly further includes a second switch and a third switch; the output terminal of the heating control unit is connected to a first end or a second end of a first metal wire via the second switch, and the end of the first metal wire away from the second switch is grounded via the third switch.

[0039] In this embodiment, the first metal wire is a shared wire used for both steering wheel heating and hands-off detection. Unlike the embodiments described above that separately set separate hands-off detection and heating wires, this embodiment uses hardware switching and software time-division multiplexing control to enable the same metal wire to perform both heating and hands-off detection functions, effectively reducing the complexity of internal steering wheel wiring and hardware costs. The second and third switches serve as switches between the heating circuit and the detection circuit, and their on / off states are controlled by the main control unit to achieve hardware link isolation and mode switching between the heating and hands-off detection functions.

[0040] In steering wheel heating mode, the main control unit controls the second and third switches to be turned on, forming a complete electrical circuit between the heating control unit and the first metal wire. The heating control unit outputs a drive current to the first metal wire, thus heating the steering wheel. At this time, the heating control unit can determine whether there is an open circuit fault in the heating circuit of the first metal wire by detecting the circuit current. In steering wheel off-hand detection and metal wire open circuit detection mode, the main control unit controls the second and third switches to be turned off, electrically isolating the heating control unit from the first metal wire to prevent the heating circuit from interfering with the capacitor detection signal. At the same time, the off-hand detection unit and the open circuit detection unit are activated to complete the off-hand state detection and the open circuit fault detection of the first metal wire. In other embodiments, a first switch is provided between the off-hand detection unit and the first metal wire. When the heating mode is turned on, the first switch needs to be turned off. Its function is to reduce the impact of the large current in the heating control unit's circuit on the ports of the off-hand detection unit and the open circuit detection unit, thereby reducing safety hazards and extending the life of components.

[0041] This embodiment achieves time-sharing multiplexing of heating and hands-off detection functions through a single metal wire and dual-switch architecture. Without increasing the number of metal wires, it simultaneously provides multiple functions such as steering wheel heating, hands-off detection, and metal wire open circuit detection, making it suitable for low-cost, integrated steering wheel system architectures.

[0042] In some embodiments, the device further includes an external communication unit; the external communication unit is connected to the main control unit and is configured to receive mode control commands from the vehicle controller or host computer, and transmit the mode control commands to the main control unit to control the main control unit to switch modes.

[0043] The external communication unit serves as the information exchange interface between this device and the vehicle system. It can be implemented using vehicle communication interfaces such as CAN bus, LIN bus, or Ethernet. It is used to receive commands from the host computer and report relevant data information to the system. During operation, when it is necessary to switch the steering wheel working mode, the host computer sends mode control commands such as hands-off detection commands, open circuit detection commands, and heating on / off commands to the external communication unit. After receiving, verifying, and converting the signals, the external communication unit transmits them to the main control unit. This allows the main control unit to control the on / off state of the switching components in real time according to the commands, thereby switching the device's working mode and performing corresponding hands-off detection, metal wire open circuit detection, or steering wheel heating operations.

[0044] This embodiment adds an external communication unit, enabling the device to respond to the centralized control of the vehicle system, realize external triggering and collaborative scheduling of the working mode, thereby effectively improving the compatibility, integration and control flexibility of the device with the vehicle controller or host computer.

[0045] For example, please refer to Figure 3 , Figure 3 The diagram shows a structural schematic of a detection device for detecting steering wheel hands-off operation. This open-circuit detection device mainly consists of an MCU control unit, an external communication unit, a hands-off detection unit, a heating control unit, a first switch, a hands-off detection wire, a heating wire, and a common ground terminal GND. The MCU control unit is bidirectionally connected to the external communication unit, the hands-off detection unit, and the heating control unit, enabling command reception, status control, and data interaction. The excitation output terminal (SEN0 terminal) of the hands-off detection unit is directly connected to one end of the hands-off detection wire, and the other end of the wire is connected to the signal receiving terminal (SEN1 terminal) of the hands-off detection unit via the first switch, forming a switchable closed-loop detection link. The output terminal of the heating control unit is connected to one end of the heating wire, and the other end is connected to the common ground terminal GND, forming an independent heating circuit. The external communication unit connects to the vehicle controller or host computer via a communication interface, enabling data and command interaction between the open-circuit detection device and the vehicle.

[0046] During the operation of the open-circuit detection device, the MCU control unit receives mode control commands from the vehicle via the external communication unit. When performing a hands-off detection operation in the hands-off detection mode, the MCU control unit controls the first switch to disconnect, electrically isolating the second end of the hands-off detection wire from the SEN1 terminal of the hands-off detection unit. The hands-off detection unit outputs an excitation waveform to the hands-off detection wire via the SEN0 terminal, determining whether the driver is holding the steering wheel based on the capacitance change caused by hand contact with the wire. When performing an open-circuit detection operation in the open-circuit detection mode, the MCU control unit controls the first switch to turn on, forming a closed-loop circuit between the hands-off detection wire and the SEN0 and SEN1 terminals of the hands-off detection unit. The hands-off detection unit determines whether an open-circuit fault has occurred by detecting whether the SEN1 terminal can receive the excitation waveform output from the SEN0 terminal. The fault information is reported to the vehicle system via the MCU control unit and the external communication unit. Meanwhile, the heating control unit independently drives the heating wire and can diagnose faults in the heating wire through circuit current detection. All units work together to achieve stable operation of the hands-off detection, wire open circuit detection, and steering wheel heating function.

[0047] For example, please refer to Figure 4 , Figure 4 The diagram shows another type of detection device for detecting steering wheel hands-off issues. This open-circuit detection device mainly consists of an MCU control unit, an external communication unit, a hands-off detection unit, a heating control unit, a second switch, a third switch, a metal wire, and a common ground terminal GND. The MCU control unit is bidirectionally connected to the external communication unit, the hands-off detection unit, and the heating control unit, enabling command transmission and reception, status control, and data interaction. The SEN0 terminal of the hands-off detection unit is directly connected to one end of the metal wire, and the other end of the metal wire can be switched via the second switch to either the SEN1 terminal of the hands-off detection unit or the common ground terminal GND. The output terminal of the heating control unit is connected to the metal wire via the third switch. The external communication unit is connected to the vehicle's upper-level system through a communication interface, enabling data and command interaction between the device and the vehicle.

[0048] During operation, the MCU control unit receives mode control commands from the vehicle via the external communication unit and controls the states of the third and second switches in a time-sharing manner. In steering wheel heating mode, when steering wheel heating is activated, the MCU control unit turns the third switch on and the second switch off. The heating control unit outputs a drive current to the wire via the third switch, energizing the wire to heat the steering wheel. The heating control unit can detect whether the wire is open-circuited by detecting the loop current. In steering wheel hands-off detection mode, when hands-off detection and wire open-circuit detection are performed, the MCU control unit turns the third switch off and the second switch on. The SEN0 terminal of the hands-off detection unit outputs an excitation waveform to the wire. This waveform is used to determine whether the driver is holding the steering wheel by detecting changes in capacitance between the wire and the human body; it also receives the excitation waveform transmitted through the wire via the SEN1 terminal. If the signal can be received normally at the SEN1 terminal, the wire is determined to be intact; otherwise, if the signal cannot be received normally at the SEN1 terminal, the wire is determined to be open circuit fault, and the fault information is reported to the vehicle system via the MCU control unit and the external communication unit, realizing the triple functions of time-division multiplexing heating, hand-off detection and open circuit detection of the same wire.

[0049] On the other hand, embodiments of this application provide a method for detecting open circuits in the metal wire of a steering wheel hands-off detection device, applicable to any of the above-described embodiments. Please refer to [link to relevant documentation]. Figure 5 The method includes the following steps: Step 100: In response to the mode control command, activate the hands-off detection unit 22 and / or the open circuit detection unit to perform steering wheel hands-off detection and / or wire open circuit detection operations.

[0050] Specifically, the main control unit receives mode control commands from the vehicle controller or host computer, and switches modes and enables functions according to the type of mode control command.

[0051] When the mode control command indicates that the steering wheel hands-off detection mode has been switched, the main control unit activates the hands-off detection unit and deactivates the open-circuit detection unit, and performs the steering wheel hands-off detection operation: the main control unit controls the excitation output terminal of the hands-off detection unit to output a continuous excitation waveform such as a sine wave or square wave to the first end of the wire assembly to establish a capacitive induction detection field. At the same time, the excitation signal returned through the wire assembly is collected through the signal receiving terminal of the hands-off detection unit, so as to determine whether the hands have moved away from the steering wheel based on the amplitude and waveform changes of the excitation signal.

[0052] When the mode control command indicates that the open circuit detection mode is switched, the main control unit starts the open circuit detection unit and stops the off-hand detection unit, and performs the open circuit detection operation of the metal wire: the main control unit controls the off-hand detection unit to continuously output the excitation waveform, and the open circuit detection unit monitors the presence of the return excitation signal through the signal receiving end. If there is no return excitation signal, it is determined that the metal wire assembly has an open circuit or breakage fault.

[0053] When the mode control command indicates a switch to hybrid detection mode, the main control unit simultaneously activates both the hands-off detection unit and the open-circuit detection unit, concurrently performing dual operations of steering wheel hands-off detection and wire open-circuit detection: the main control unit controls the hands-off detection unit to synchronously output an excitation waveform and determine the hands-off status based on capacitance changes; the open-circuit detection unit monitors the on / off status of the return signal in parallel to diagnose wire open-circuit faults. Finally, the main control unit integrates the two types of detection results and outputs them to the host computer. Hybrid detection mode refers to simultaneously activating the steering wheel hands-off detection mode and the open-circuit detection mode.

[0054] This embodiment controls the start and stop of the open circuit detection unit and the hands-off detection unit by responding to mode control commands from the main control unit, enabling flexible switching between steering wheel hands-off detection and wire open circuit detection operations. As can be seen, this embodiment does not require additional dedicated detection hardware; with only simple circuit modifications, it can achieve real-time detection of open circuit or breakage faults in the wire assembly without affecting the accuracy of the original capacitive hands-off detection function. This not only improves the reliability and driving safety of the hands-off detection system but also effectively controls hardware costs and wiring complexity.

[0055] In some embodiments, the apparatus further includes a switching assembly, the switching assembly including a first switch. The method further includes: Step 200: In response to the mode control command indicating that the first switch is turned on, the open circuit detection mode of the metal wire is activated to perform the open circuit detection operation of the metal wire.

[0056] Specifically, when the main control unit receives a mode control command instructing the activation of the open-circuit detection mode for the metal wire, it outputs a conduction control signal to the control terminal of the first switch, causing the first switch to switch from an open state to a conduction state. At this time, the second end of the metal wire assembly is electrically connected to the signal receiving terminal of the off-hand detection unit through the conducting first switch, forming a closed-loop detection circuit together with the excitation output terminal of the off-hand detection unit. Then, the off-hand detection unit outputs a preset excitation waveform to the metal wire assembly through its excitation output terminal. After being transmitted through the metal wire assembly, the excitation waveform flows back to the signal receiving terminal of the off-hand detection unit through the first switch. The main control unit determines whether the metal wire assembly has an open circuit or breakage fault based on whether the signal receiving terminal can normally receive the excitation waveform, thereby completing the open-circuit detection operation of the metal wire.

[0057] As can be seen, this embodiment activates the first switch by responding to the mode control command, thus constructing a closed-loop detection circuit. It can achieve active detection of open circuit faults in the metal wire without additional hardware. It can promptly identify and report faults such as broken or poor contact in the metal wire, avoiding driving safety hazards caused by the failure of the hands-off detection function. It can significantly improve the reliability and fault diagnosis capability of the steering wheel hands-off detection system, while meeting the requirements of automotive functional safety for fault detectability.

[0058] In some embodiments, the apparatus further includes a switching assembly, the switching assembly including a first switch. The method further includes: Step 300: In response to the mode control command indicating that the first switch is turned off, the steering wheel off-hand detection mode is activated to perform the steering wheel off-hand detection operation.

[0059] Specifically, when the main control unit receives a mode control command indicating that the steering wheel hands-off detection mode is activated, it outputs a disconnect control signal to the control terminal of the first switch, causing the first switch to switch from the on state to the off state. At this time, the second end of the wire assembly is electrically isolated from the signal receiving terminal of the hands-off detection unit, and the wire assembly returns to a single-ended excitation, approximately suspended working state. Then, the hands-off detection unit outputs a continuous excitation waveform to the wire assembly through its excitation output terminal. The wire assembly, acting as a capacitive sensing electrode, feeds back the capacitance change caused by the driver's hand contacting the steering wheel to the hands-off detection unit. Based on the capacitance signal change collected by the hands-off detection unit, the main control unit determines whether the driver is holding the steering wheel, thereby completing the steering wheel hands-off detection operation.

[0060] As can be seen, this embodiment disconnects the first switch by responding to the mode control command, so that the wire assembly returns to the suspended working state of single-end excitation, thereby avoiding interference of the switching circuit on the capacitance detection signal. This allows the hands-off detection unit to accurately identify the driver's grip state based on the capacitance change between the wire and the human body, thus ensuring the sensitivity and accuracy of the hands-off detection function.

[0061] In some embodiments, the device further includes a heating control unit, and a switching assembly including a second switch and a third switch, wherein the heating control unit is connected to a first end or a second end of the first metal wire via the second switch; the end of the first metal wire furthest from the second switch is grounded via the third switch. The method further includes step 400, specifically comprising: Step 400: In response to the mode control command, control the second switch and the third switch to be turned on, and control the heating control unit to output a drive signal to turn on the steering wheel heating mode.

[0062] Specifically, in response to a mode control command instructing the steering wheel heating mode to be activated, the main control unit, upon receiving the command, outputs conduction control signals to the control terminals of the second and third switches, respectively, causing the second and third switches to be simultaneously in a conducting state. This connects the output terminal of the heating control unit to one end of the first metal wire via the conducting second switch, while ensuring that the end of the first metal wire furthest from the second switch is reliably grounded via the conducting third switch, thus forming a steering wheel heating drive circuit. Then, the main control unit controls the heating control unit to output a preset drive current and power signal, energizing the first metal wire and heating it to achieve the steering wheel heating function.

[0063] Optionally, the heating control unit monitors parameters such as circuit current and voltage in real time during operation to diagnose whether there are faults such as open circuit or short circuit in the first metal wire, and feeds back the fault diagnosis results to the main control unit, which then completes the status recording and information reporting to ensure the stable and reliable operation of the heating function.

[0064] In some embodiments, the device further includes a heating control unit, the switching assembly includes a second switch, and the method further includes step 500, specifically including: Step 500: In response to the mode control command, the second switch, the third switch, and the heating control unit are disconnected, and the steering wheel off-hand detection mode is activated.

[0065] Specifically, in response to the mode control command to activate the steering wheel hands-off detection mode, the main control unit, upon receiving the mode control command, sends disconnect control signals to the control terminals of the second and third switches respectively, causing the second and third switches to switch from on to off, cutting off the connection between the heating control unit and the first metal wire and disconnecting the grounding path of the first metal wire. Simultaneously, the main control unit controls the heating control unit to stop outputting drive signals, completely shutting off the heating circuit and eliminating interference from the heating circuit to the capacitance detection. Then, the main control unit activates the hands-off detection unit, outputting a continuous excitation waveform to the first metal wire from the excitation output terminal of the hands-off detection unit, establishing a capacitance induction detection field. The hands-off detection unit collects the return current signal through the signal receiver terminal and, combined with the capacitance change, determines whether the driver is holding the steering wheel, completing the switching and execution of the steering wheel hands-off detection mode.

[0066] This embodiment achieves reliable switching of the same metal wire between the steering wheel heating mode and the hands-off detection mode by controlling the on / off state of the second switch, the third switch, and the heating control unit in a time-sharing manner. This effectively isolates the interference of the heating circuit on the capacitor detection signal, ensuring the accuracy of hands-off detection. No additional metal wire or hardware module is required, which can reduce the complexity of internal wiring and hardware costs of the steering wheel. At the same time, it takes into account the functions of heating, hands-off detection, and open circuit detection of the metal wire, thereby effectively improving the integration, reliability, and safety of the steering wheel hands-off detection system.

[0067] For example, please refer to Figure 6 , Figure 6 As shown Figure 3 A schematic diagram of the internal circuit structure of the corresponding open-circuit detection device for metal wires is shown. The internal circuit structure of this device is divided into two main parts: the steering wheel end 10 and the single-board end 20. The single-board end 20 includes an MCU control unit 21, a switching assembly, and a hands-off detection unit 22 (such as an AS8579 chip). Optionally, the switching assembly is a first switch 24, specifically an NMOS transistor. The first terminal of the MCU control unit 21 is connected to the gate of the first switch 24. The drain and source of the first switch 24 are respectively connected to the second terminal of the first metal wire 11 at the steering wheel end 10 and the SEN1 terminal of the hands-off detection unit 22. The SEN0 terminal of the hands-off detection unit 22 is directly connected to the first terminal of the first metal wire 11, and the first metal wire 11 is entirely arranged at the steering wheel end 10. This forms a switchable closed-loop circuit (i.e., ...) from the SEN0 terminal of the hands-off detection unit 22, the first metal wire 11, the switching assembly (such as an NMOS transistor), to the SEN1 terminal of the hands-off detection unit 22. Figure 6 (The link indicated by the red dashed arrow in the middle) The MCU control unit 21 controls the first switch 24 to turn on and off, thereby realizing the hardware link switching between the steering wheel off-hand detection mode and the metal wire open circuit detection mode. At the same time, a communication link is established between the MCU on the single board 20 and the off-hand detection unit 22 to realize the issuance of mode commands and the interaction of detection data.

[0068] In this open-circuit detection device for metal wires, one end of the first metal wire 11 is connected to the SEN0 terminal of the off-hand detection unit 22 on the single-board terminal 20, and the other end is connected to the SEN1 terminal of the off-hand detection unit 22 via a first switch 24 driven by the MCU control unit 21, forming a switchable signal loop. When the first switch 24 is turned off by the MCU control unit 21, the metal wire is in a single-ended excitation and approximately suspended working state. The off-hand detection unit 22 outputs an excitation waveform through the SEN0 terminal, using the capacitance change caused by the human hand touching the metal wire to detect whether the driver is holding the steering wheel. When the first switch 24 is turned on by the MCU control unit 21, the excitation waveform output by the SEN0 terminal can be transmitted to the SEN1 terminal via the metal wire. The off-hand detection unit 22 determines whether the first metal wire 11 has an open circuit or breakage fault by detecting whether the SEN1 terminal can normally receive the excitation signal, thus realizing the open-circuit diagnosis of the metal wire without affecting the normal off-hand detection function.

[0069] Meanwhile, the second terminal of the MCU control unit 21 is connected to the first terminal of the heating control unit 23. The second terminal of the heating control unit 23 is connected to one end of the second metal wire 12, and the other end of the second metal wire 12 is grounded. The MCU control unit 21 drives the heating control unit 23 to heat the second metal wire 12.

[0070] For example, please refer to Figure 7 , Figure 7 As shown Figure 4 The internal circuit structure diagram of the corresponding open-circuit detection device for metal wires is shown. This open-circuit detection device is divided into two main parts: the steering wheel end 10 and the single-board end 20. The single-board end 20 includes an MCU control unit 21, a heating control unit 23, a hands-off detection unit 22 (such as an AS8579 chip), and a second switch 25 and a third switch 26. Optionally, the second switch 25 and the third switch 26 are NMOS transistors. The output terminal of the MCU control unit 21 is connected to the gates of the second switch 25 and the third switch 26, respectively. The drain and source of the third switch 26 are connected to the output terminal of the heating control unit 23 and one end of the third metal wire 13 of the steering wheel end 10, respectively. The drain and source of the second switch 25 are connected to the other end of the third metal wire 13 and the common ground terminal GND, respectively. The SEN0 terminal of the hands-off detection unit 22 is connected to one end of the third metal wire 13, and the SEN1 terminal is connected to the other end of the third metal wire 13, forming a time-division multiplexing hardware architecture consisting of a heating circuit and a detection circuit. The heating circuit refers to the circuit consisting of the heating control unit 23, the third switch 26, the third metal wire 13, the second switch 25, and GND. The detection circuit refers to the circuit consisting of the SEN0 terminal of the off-hand detection unit 22, the third metal wire 13, and the SEN1 terminal of the off-hand detection unit 22. The MCU control unit 21 establishes a communication link with both the heating control unit 23 and the off-hand detection unit 22 to enable the issuance of mode commands and the exchange of detection data.

[0071] This device achieves three functions—steering wheel heating, hands-off detection, and open-circuit detection—by time-division multiplexing the same metal wire. Specifically, when the driver activates the steering wheel heating function, the MCU control unit 21 turns on the third switch 26 and the second switch 25, and simultaneously controls the heating control unit 23 to output a drive current. The current flows along the link formed by the heating control unit 23, the third switch 26, the third metal wire 13, the second switch 25, and GND (i.e., Figure 7 The flow of current (indicated by the blue dashed arrow) causes the third metal wire 13 to heat up. The heating control unit 23 determines whether the third metal wire 13 is open-circuited by detecting the current in the circuit. If there is no current, it determines that the third metal wire 13 is broken. When the driver has not activated the heating function, the MCU control unit 21 disconnects the third switch 26 and the second switch 25 and turns off the output of the heating control unit 23. The hands-off detection unit 22 outputs a continuous excitation waveform to the third metal wire 13 through the SEN0 channel of the hands-off detection unit 22. At this time, on the one hand, the driver can determine whether he is holding the steering wheel by detecting the capacitance change between the third metal wire 13 and the human body. On the other hand, the excitation waveform follows the link formed by the SEN0 terminal of the hands-off detection unit 22, the third metal wire 13 and the SEN1 terminal of the hands-off detection unit 22 (i.e., ... Figure 7 The link (indicated by the red dashed arrow) is transmitted. The off-hand detection unit 22 receives the signal through the SEN1 channel. If it can receive the signal normally, it is determined that the third metal wire 13 is in good condition. If it cannot receive the signal, it is determined that the third metal wire 13 has an open circuit fault. The status diagnosis of the third metal wire 13 can be completed independently in both modes without the need to add a special detection metal wire.

[0072] It needs to be stated that, Figure 7 The link indicated by the red dashed arrow is always in a conductive state. In actual use, when the heating function is activated by turning on the second switch 25 and the third switch 26 in the MCU control unit 21, the link indicated by the blue dashed arrow is conductive. At this time, the conductivity of the link indicated by the red dashed arrow will not affect the blue link. In addition, the effectiveness of real-time detection of the conductivity of the link indicated by the red dashed arrow can be determined periodically by the software strategy to determine whether the metal wire is working properly and whether an open circuit fault has occurred.

[0073] On the other hand, this embodiment provides a vehicle, including: Steering wheel; and, The detection device for detecting steering wheel removal as described above, and the device is used to perform the steps of the detection method for detecting steering wheel removal as described above.

[0074] This embodiment also provides a computer-readable storage medium having a computer program stored thereon, the computer program being loaded by a processor to perform the steps of any of the methods in the above embodiments.

[0075] In the embodiments of this application, the storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM), etc.

[0076] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0077] The foregoing has provided a detailed description of a detection device, method, and vehicle for detecting steering wheel hands off the wheel, as provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A detection device for steering wheel hands-off detection, characterized in that include: Hand-off detection unit; Open circuit detection unit; A metal wire assembly, wherein a first end of the metal wire assembly is connected to the excitation output terminal of the off-hand detection unit, and a second end of the metal wire assembly is connected to the signal receiving terminal of the off-hand detection unit; the open-circuit detection unit is connected to the signal receiving terminal of the off-hand detection unit. The main control unit, connected to the hands-off detection unit and the open-circuit detection unit, is configured to activate the hands-off detection unit and / or the open-circuit detection unit in response to a mode control command, so as to perform steering wheel hands-off detection and / or wire open-circuit detection operations.

2. The detection device for hands-off detection of a steering wheel according to claim 1, characterized in that The device also includes a switch assembly, and the second end of the wire assembly is connected to the signal receiving end of the off-hand detection unit via the switch assembly. The main control unit is connected to the hands-off detection unit and the switch assembly respectively, and is configured to control the switch assembly to turn on and off in response to the mode control command, so as to perform the steering wheel hands-off detection or the wire open circuit detection operation.

3. The detection device for detecting when a steering wheel is removed from the hands according to claim 2, characterized in that, The switching assembly includes a first switch; The metal wire assembly includes a first metal wire; The first end of the first metal wire is connected to the excitation output terminal of the off-hand detection unit, and the second end of the first metal wire is connected to the signal receiving terminal of the off-hand detection unit via the first switch.

4. The detection device for detecting when a steering wheel is removed from the hands according to claim 1, characterized in that, The device also includes a heating control unit; The wire assembly includes a second wire; The first end of the second metal wire is connected to the heating control unit, and the second end of the second metal wire is grounded.

5. The detection device for detecting when a steering wheel is removed from the hands according to claim 3, characterized in that, The device also includes a heating control unit; The switching assembly further includes a second switch and a third switch; The heating control unit is connected to either the first or second end of the first metal wire via the second switch; The end of the first metal wire furthest from the second switch is grounded through the third switch.

6. The detection device for detecting when a steering wheel is removed from the hands according to claim 2, characterized in that, The device also includes an external communication unit; The external communication unit is connected to the main control unit and is configured to receive the mode control command and transmit the mode control command to the main control unit.

7. A detection method for detecting when a steering wheel is removed from the hands, characterized in that, The method, applied to the detection device for detecting steering wheel hands-off as described in any one of claims 1 to 6, comprises the following steps: In response to the mode control command, the hands-off detection unit and / or the open circuit detection unit are activated to perform steering wheel hands-off detection and / or wire open circuit detection operations.

8. The detection method for detecting steering wheel removal from hands according to claim 7, characterized in that, The device further includes a switching assembly, the switching assembly including a first switch; The method further includes: In response to the mode control command, the first switch is turned on to activate the open circuit detection mode for the metal wire.

9. The detection method for detecting steering wheel removal from hands according to claim 7, characterized in that, The device also includes a heating control unit and a switching assembly; The switching assembly includes a second switch and a third switch; The heating control unit is connected to either the first or second end of the first metal wire via the second switch; The end of the first metal wire furthest from the second switch is grounded through the third switch; The method further includes: In response to the mode control command, the second switch and the third switch are turned on, and the heating control unit is controlled to output a drive signal to turn on the steering wheel heating mode.

10. The detection method for detecting steering wheel removal from hands according to claim 9, characterized in that, The method further includes: In response to the mode control command, the second switch, the third switch, and the heating control unit are disconnected, and the steering wheel off-hand detection mode is activated.

11. A vehicle, characterized in that, include: steering wheel; as well as, The detection device for detecting steering wheel removal as described in any one of claims 1 to 6, wherein the device is used to perform the steps of the detection method for detecting steering wheel removal as described in any one of claims 7 to 10.

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