Occupant status detection device

Abstract

The present invention provides an occupant state detection device to which a touchpad and a grip sensor are both provided and in which the grip sensor and the touchpad can operate normally and a computer program.　The occupant state detection device comprises: a steering wheel (2) having a touchpad (20) that can be operated using electrostatic capacitance and a grip sensor (21) that detects whether a driver is gripping a rim portion; an operation determination unit (12) that makes an operation determination regarding whether the touchpad (20) is being operated; and a grip determination unit (11) that makes a grip determination regarding whether the rim portion of the steering wheel (2) is being gripped.

Description

[Technical field]

[0001] The present invention relates to an occupant condition detection device. Place Regarding. [Background technology]

[0002] 2. Description of the Related Art Conventionally, steering wheels equipped with a touch pad have been widely used as an HMI (Human Machine Interface) for a display unit provided on an instrument panel or a center console of a vehicle.

[0003] For example, Patent Document 1 discloses a steering wheel that is configured to determine the operation direction based on a start area and an end area where a tracing operation is detected among multiple areas defined on an operation surface of the steering wheel, and determines the operation direction by adjusting the multiple areas depending on the grip position of the ring portion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-166878 A Summary of the Invention [Problem to be solved by the invention]

[0005] There is a widely known technology that monitors whether or not the driver is gripping the rim portion, and executes functions such as ACC (Adaptive auto cruise) and LKAS (Lane Keeping Assist System) depending on the gripping state.

[0006] Furthermore, many steering wheels are provided with a grip sensor that monitors the gripping state in addition to the above-mentioned touch pad.

[0007] In this way, in a steering wheel having both a touchpad and a grip sensor, the driver may operate the touchpad with his / her fingertips while gripping the rim. In this case, the grip sensor provided on the rim and the touchpad are activated simultaneously. However, if both the touchpad and the grip sensor are activated based on a change in capacitance, the electrodes of the grip sensor and the touchpad are connected via the driver's hand, which may prevent normal operation.

[0008] The steering wheel of Patent Document 1 is also provided with both a touch pad and a grip sensor, but Patent Document 1 does not devise a solution to such problems and is therefore unable to solve them.

[0009] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an occupant status detection device having both a touch pad and a grip sensor, which can prevent the grip sensor and the touch pad from being unable to operate normally when they are operated simultaneously. Place The purpose is to provide. [Means for solving the problem]

[0010] The occupant status detection device of the present invention comprises a steering wheel having a touchpad that can be operated using capacitance and a grip sensor that detects whether the driver is gripping the rim portion, an operation determination unit that makes an operation determination as to whether the touchpad is being operated, and a grip determination unit that makes a grip determination as to whether the rim portion of the steering wheel is being gripped.

[0011] In the present invention, the grip determination unit performs the grip determination according to a result of the operation determination. For example, when the operation determination unit determines that the touchpad is operated, the grip determination unit does not perform the grip determination in preparation for interference between the operation determination and the grip determination.

[0012] The computer program of the present invention causes a computer to execute a process of making an operation determination as to whether a touchpad that can be operated using electrostatic capacitance provided on a steering wheel is being operated, and a grip determination as to whether a rim portion of the steering wheel is being gripped.

[0013] In the present invention, the grip determination is performed according to a result of the operation determination. For example, when it is determined that the touch pad is operated, the grip determination is not performed in order to prevent interference between the operation determination and the grip determination. Effect of the Invention

[0014] According to the present invention, in an occupant status detection device having both a touch pad and a grip sensor, it is possible to prevent a malfunction in operation when the grip sensor and the touch pad are operated simultaneously. [Brief description of the drawings]

[0015] [Figure 1] 1 is a block diagram showing an example of the configuration of a steering wheel device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a front view of the steering wheel of the steering wheel device according to the present embodiment. [Diagram 3] 4 is an illustrative diagram showing an example of operating a touch pad in the steering wheel device of the present embodiment. FIG. [Figure 4] 5 is a flowchart illustrating the process of operation determination and grip determination in the steering wheel device of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] An occupant condition detection device according to an embodiment of the present invention will be described in detail below with reference to the drawings, taking a steering wheel device as an example.

[0017] 1 is a block diagram showing an example of the configuration of a steering wheel device 100 according to this embodiment. The steering wheel device 100 (occupant state detection device) includes a steering wheel 2 and a control device 1. The control device 1 is communicatively connected to various ECUs, such as a driving assistance ECU that executes processing related to an advanced driving assistance system, via an in-vehicle network provided in the vehicle.

[0018] The steering wheel 2 includes a grip sensor 21 and a touch pad 20. The grip sensor 21 and the touch pad 20 detect, for example, electrostatic capacitance coupled to electrodes provided on the steering wheel 2.

[0019] The control device 1 is provided on, for example, a steering wheel 2, and includes a grip determination unit 11, an operation determination unit 12, and a communication unit 13. The grip determination unit 11 acquires a detection value of the capacitance detected by the grip sensor 21, and determines whether the steering wheel 2 is in a gripped state or a non-grip state based on the detection value. Here, the gripped state is a state in which the driver grips the steering wheel 2, and the non-grip state is a state in which the driver does not grip the steering wheel 2 and lets go of it.

[0020] The grip determination unit 11 includes an arithmetic processing unit (not shown) such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). As described above, the grip determination unit 11 determines whether the steering wheel 2 is in a gripped state or a non-grip state (hereinafter referred to as grip determination) based on the detection value of the capacitance detected by the grip sensor 21. As described later, the grip determination unit 11 also performs the grip determination depending on whether the touch pad 20 is operated by the driver. The result of the grip determination by the grip determination unit 11 is transmitted to the driving assistance ECU or the like via the communication unit 13.

[0021] The grip determination unit 11 includes a capacitance measurement circuit (not shown). The capacitance measurement circuit is an electric circuit for measuring a detection value of capacitance. The capacitance measurement circuit processes an electric signal acquired from the grip sensor 21 and calculates a detection value of capacitance. The grip determination unit 11 performs the grip determination using the calculated detection value of capacitance.

[0022] The grip determination unit 11 also has a storage unit 111. The storage unit 111 includes memory elements such as a RAM (Random Access Memory) and a ROM (Read Only Memory), and stores programs or data required for the grip determination unit 11 to execute processing. The storage unit 111 also temporarily stores data required for the grip determination unit 11 to execute processing. Furthermore, the storage unit 111 stores a capacitance threshold value used when the grip determination unit 11 makes the grip determination.

[0023] The communication unit 13 is a communication interface for transmitting and receiving information to and from other in-vehicle devices such as various ECUs via an in-vehicle network. The communication unit 13 is connected to a communication line (LAN) provided in the vehicle, and transmits and receives information to and from other ECUs, etc. For example, the communication unit 13 transmits the result of the grip determination by the grip determination unit 11 to a driving assistance ECU, etc.

[0024] As described below, the operation determination unit 12 generates an operation instruction for operating a UI (User Interface) displayed on a display unit provided in a HUD (Head Up Display), an instrument panel, or a center console, based on the capacitance value sent from the touch pad 20. Such an operation instruction is transmitted via the communication unit 13 to an ECU associated with the HUD, the instrument panel, or the center console.

[0025] The operation determination unit 12 also has a storage unit 121. The storage unit 121 is similar to the storage unit 111, and detailed description thereof will be omitted. The storage unit 121 also stores a capacitance threshold value used when determining whether or not the touch pad 20 is being operated (hereinafter, referred to as operation determination).

[0026] The operation determination unit 12 performs the operation determination by comparing the capacitance value sent from the touchpad 20 with a threshold value stored in the storage unit 121. Furthermore, when the operation determination unit 12 determines that the touchpad 20 is operated as a result of the operation determination, it transmits a first operation determination signal to the grip determination unit 11, and when it determines that the touchpad 20 is not operated, it transmits a second operation determination signal to the grip determination unit 11.

[0027] FIG. 2 is a front view of the steering wheel 2 of the steering wheel device 100 according to this embodiment.

[0028] The grip sensor 21 detects a change in capacitance (hereinafter referred to as capacitance detection) caused by contact between the driver's hand and the steering wheel 2. Such capacitance detection is performed depending on whether the touch pad 20 is operated by the driver. That is, the grip sensor 21 performs capacitance detection depending on whether the operation determination unit 12 is issuing a first operation determination signal or a second operation determination signal.

[0029] Grip sensor 21 has multiple electrodes 2a provided inside rim portion 10, which will be described later. Electrodes 2a are provided inside each of three equal circumferential portions of rim portion 10. Note that the number of electrodes 2a is not limited to three, and may be two or less, or four or more.

[0030] The electrode 2a is connected to, for example, a C / V conversion circuit (not shown) associated with the grip sensor 21. The C / V conversion circuit applies, for example, an AC voltage of a predetermined amplitude to the electrode 2a, and outputs an AC voltage corresponding to the magnitude of the capacitance coupled to the electrode 2a. The capacitance measurement circuit detects the capacitance coupled to the electrode 2a by detecting the output voltage.

[0031] When the steering wheel 2 is not gripped, the electrode 2a is electrically capacitively coupled to the GND (ground) of the vehicle body, etc., via the air in the vehicle cabin. When the steering wheel 2 is gripped, i.e., when the driver's hand is in contact with the rim portion 10, the electrode 2a is capacitively coupled to the driver's body by approaching the driver's hand. When the electrode 2a is capacitively coupled to the GND, the capacitance is very small because of the capacitive coupling with the ground surface. In contrast, the human body has a certain degree of conductivity, so the capacitance due to the coupling between the driver's body and the electrode 2a is larger than the capacitance due to the coupling between the GND and the electrode 2a.

[0032] The touchpad 20 is a known device in itself, in which, for example, a plurality of driving electrodes and a plurality of detection electrodes are arranged in a cross-like manner while maintaining insulation behind an operation surface 201 (see FIG. 2). The touchpad 20 detects a capacitance that changes when the driver's fingertip touches the operation surface 201. A coordinate system is set on the operation surface 201, and the touchpad 20 receives operations such as touching, tapping, and dragging using the driver's fingertip.

[0033] The touchpad 20 scans all combinations of the drive electrodes and detection electrodes to detect the capacitance for each combination. The touchpad 20 then calculates the coordinates of the position related to the operation based on the threshold value of the storage unit 121. The touchpad 20 periodically outputs detection coordinates representing the calculated coordinates to the operation determination unit 12. The operation determination unit 12 generates an operation instruction for moving a cursor on the UI of the display unit, an operation instruction for selecting one of the selection keys, etc. based on the detection coordinates.

[0034] The touchpad 20 may be a mutual capacitance type touchpad, or may be configured as a self-capacitance type touchpad. In the case of the mutual capacitance type, when the driver's fingertip touches the operation surface 201, the capacitance decreases compared to the case of capacitive coupling to GND. In addition, in the case of the self-capacitance type, when the driver's fingertip touches the operation surface 201, the capacitance increases. In the following, an example will be described in which the touchpad 20 is a mutual capacitance type.

[0035] The steering wheel 2 includes a circular ring-shaped rim portion 10 and a hub portion 4 that is disposed at the center of the rim portion 10 and houses an airbag (not shown). The hub portion 4 is connected to the rim portion 10 by three spoke portions 3.

[0036] The rim portion 10 is covered with a skin material such as leather, and the hub portion 4 and the spokes 3 are covered with, for example, a resin material. As described above, the three electrodes 2a are provided on the inside of the rim portion 10 along the circumferential direction of the rim portion 10. In the following, the rim portion 10 will be described as having a circular ring shape, but is not limited to this. The rim portion 10 may be non-circular (for example, D-shaped or C-shaped).

[0037] In other words, in the circumferential direction of the rim portion 10, if the top and bottom positions are the 12 o'clock and 6 o'clock directions, and the left and right positions are the 9 o'clock and 3 o'clock directions, like on a clock, the spoke portions 3 are located at the 3 o'clock, 6 o'clock, and 9 o'clock positions clockwise.

[0038] Of the three spoke portions 3, for example, the resin member of the spoke portion 3 at the 9 o'clock position is provided with an operation panel 22 having a number of operation buttons so that the driver can operate in-vehicle devices such as audio while driving.

[0039] In addition, a touchpad 20 is provided on the operation panel 22 provided on the spoke portion 3 in the 3 o'clock direction. The touchpad 20 has a substantially rectangular, flat operation surface 201. As described above, the operation surface 201 accepts operations by the driver, such as touching, tapping, and dragging. The touchpad 20 (operation surface 201) is provided near the rim portion 10, extending from the center of the steering wheel 2 to a portion of the spoke portion 3.

[0040] In the steering wheel device 100 according to this embodiment, the control device 1 (grip determination unit 11) performs grip determination based on the voltage value (capacitance) from the grip sensor 21, as described above.

[0041] In the grip determination unit 11, the capacitance measurement circuit processes the electric signal indicating the capacitance detected by the grip sensor 21 to obtain a detection value of the capacitance. The grip determination unit 11 compares the obtained detection value (capacitance) with a threshold value stored in the memory unit 111.

[0042] The grip determination unit 11 performs a grip determination as to whether the steering wheel 2 is in a gripped state or not based on the detection value and the threshold value. For example, the grip determination unit 11 determines that the steering wheel 2 is in a non-grip state when the acquired detection value is less than the threshold value, and determines that the steering wheel 2 is in a gripped state when the acquired detection value is equal to or greater than the threshold value. The result of the grip determination by the grip determination unit 11 is sent to the driving assistance ECU by the communication unit 13.

[0043] The driving assistance ECU, which has received a signal indicating the result of the gripping determination from the control device 1, executes processing related to driving assistance based on the received result of the gripping determination. For example, during autonomous driving, if the driving assistance ECU receives a result of the gripping determination indicating that the steering wheel 2 is in an ungripped state, the driving assistance ECU ends the autonomous driving. Note that the processing of the driving assistance ECU is not limited to autonomous driving, and may be, for example, lane keep assist, parking assist, etc.

[0044] 3 is an illustrative diagram showing an example of operating the touch pad 20 in the steering wheel device 100 of this embodiment. For convenience, the driver's hand 200 is shown by a dashed line in FIG.

[0045] As described above, since the touch pad 20 is provided close to the rim portion 10, the driver can operate the touch pad 20 with, for example, the tip of the thumb while gripping the rim portion 10. In other words, the rim portion 10 can be gripped and the touch pad 20 can be operated at the same time.

[0046] However, at this time, the driver's hand comes into contact with both the electrode 2a of the grip sensor 21 and the electrode of the touch pad 20. In such a case, the electrode 2a of the grip sensor 21 and the electrode of the touch pad 20 are in electrical contact with each other via the driver's hand. Since both the touch pad 20 and the grip sensor 21 measure capacitance, there is a possibility that normal measurement cannot be performed at this time. This may also lead to erroneous judgments in the grip judgment and the operation judgment, and a malfunction of the UI of the display unit.

[0047] In contrast, in the steering wheel device 100 of this embodiment, the grip determination unit 11 performs the grip determination depending on whether or not the driver is operating the touch pad 20, thereby solving the above-mentioned problem. This will be described in detail below.

[0048] FIG. 4 is a flowchart illustrating the operation determination and grip determination processes in the steering wheel device 100 of the present embodiment.

[0049] First, the grip determination unit 11 determines whether or not the engine of the vehicle has started to drive (step S201). The grip determination unit 11 performs such a determination by monitoring an ignition signal that is output for a predetermined period of time when the ignition (ignition device) is ON.

[0050] When the grip determination unit 11 determines that the engine of the vehicle has not started to drive (step S201: NO), it repeats this determination. When the grip determination unit 11 determines that the engine of the vehicle has started to drive (step S201: YES), it starts the grip determination based on the result of the capacitance detection by the grip sensor 21 (step S202). That is, the grip determination unit 11 starts the grip determination based on the capacitance from the grip sensor 21.

[0051] Thereafter, the grip determination unit 11 transmits the result of the grip determination to the driving assistance ECU or the like via the communication unit 13 until the operation determination unit 12 transmits the first operation determination signal.

[0052] The operation determination unit 12 also monitors the ignition signal to determine whether the vehicle engine has started to operate (step S101). When the operation determination unit 12 determines that the vehicle engine has not started to operate (step S101: NO), the operation determination unit 12 repeats this determination. When the operation determination unit 12 determines that the vehicle engine has started to operate (step S101: YES), the operation determination unit 12 starts the operation determination (step S102). That is, the operation determination unit 12 starts comparing the capacitance value sent from the touchpad 20 with a threshold value stored in the memory unit 121.

[0053] After starting the operation determination, the operation determination unit 12 determines whether or not the touchpad 20 is being operated (step S103). If the operation determination unit 12 determines that the touchpad 20 is not being operated (step S103: NO), the operation determination unit 12 repeats this determination. If the operation determination unit 12 determines that the touchpad 20 is being operated (step S103: YES), the operation determination unit 12 transmits a first operation determination signal to the grip determination unit 11 (step S104).

[0054] When the grip determination unit 11 receives the first operation determination signal from the operation determination unit 12, the grip determination unit 11 interrupts the grip determination being performed (step S203).

[0055] Next, the grip determination unit 11 determines the grip state as a result of the grip determination, regardless of the result of the capacitance detection from the grip sensor 21 (step S204). Such a grip determination result is transmitted to the driving assistance ECU, etc. via the communication unit 13.

[0056] Thereafter, the grip determination unit 11 determines whether or not a second operation determination signal has been received from the operation determination unit 12 (step S205). If the grip determination unit 11 determines that the second operation determination signal has not been received from the operation determination unit 12 (step S205: NO), the process returns to step S204, and the grip determination unit 11 determines the result of the grip determination as a grip state.

[0057] On the other hand, after transmitting the first operation determination signal to the grip determination unit 11 in step S104, the operation determination unit 12 determines whether or not a predetermined time has elapsed based on the timing result of a timing unit (not shown) (step S105).

[0058] If the operation judgment unit 12 determines that a predetermined time has not elapsed since transmitting the first operation judgment signal (step S105: NO), the processing returns to step S104, and the operation judgment unit 12 transmits the first operation judgment signal to the grip judgment unit 11.

[0059] Furthermore, when the operation determination unit 12 determines that a predetermined time has elapsed since transmitting the first operation determination signal (step S105: YES), it again determines whether or not the touchpad 20 is being operated (step S106). When the operation determination unit 12 determines that the touchpad 20 is being operated (step S106: YES), the process returns to step S104, and the operation determination unit 12 transmits the first operation determination signal to the grip determination unit 11.

[0060] That is, after transmitting the first operation determination signal, the operation determination unit 12 periodically repeats the determination of whether or not the touchpad 20 is being operated, and if it determines that the touchpad 20 is being operated, continues to transmit the first operation determination signal to the grip determination unit 11.

[0061] On the other hand, when the operation determination unit 12 determines that the touch pad 20 has not been operated (step S106: NO), the operation determination unit 12 transmits a second operation determination signal to the grip determination unit 11 (step S107). After that, the process ends.

[0062] In this way, when the second operation determination signal is sent from the operation determination unit 12, the grip determination unit 11 determines that the second operation determination signal has been received (step S205: YES). When it is determined that the second operation determination signal has been received, the grip determination unit 11 resumes the interrupted grip determination (step S206). That is, the grip determination unit 11 resumes the grip determination based on the capacitance from the grip sensor 21. After this, the process ends.

[0063] The above-mentioned process is repeated, for example, until the engine of the vehicle is stopped.

[0064] In the steering wheel device 100 of this embodiment, as described above, when the operation judgment unit 12 emits the first operation judgment signal, i.e., when the driver is operating the touchpad 20, the grip judgment unit 11 suspends the grip judgment, and then when the operation judgment unit 12 emits the second operation judgment signal, i.e., when the driver stops operating the touchpad 20, the grip judgment unit 11 resumes the grip judgment. Therefore, while the driver is operating the touch pad 20, the capacitance detection by the grip sensor 21 is not performed and is invalidated. This makes it possible to prevent a problem in advance in which the capacitance cannot be measured normally due to electrical contact between the electrode 2a of the grip sensor 21 and the electrode of the touch pad 20 through the driver's hand.

[0065] Furthermore, in the steering wheel device 100 of this embodiment, as described above, when the first operation determination signal is transmitted and the grip determination by the grip determination unit 11 is interrupted, the grip determination unit 11 uniformly determines the result of the grip determination as a grip state regardless of the result of the capacitance detection from the grip sensor 21. In this case, since the driver operates the touch pad 20 with his / her fingertips while gripping the rim portion 10 (see FIG. 3), uniformly determining the state as a grip state is an appropriate grip determination. Therefore, even if the grip determination is interrupted, an appropriate grip determination result can be output to the driving assistance ECU, etc.

[0066] In the steering wheel device 100 of this embodiment, the control device 1 is built-in, so an in-vehicle LAN is not used. This makes it possible to improve responsiveness without putting a strain on the data communication band of the in-vehicle LAN.

[0067] In the above, the control device 1 is provided on the steering wheel 2, but the present invention is not limited to this. For example, the control device 1 may be provided on the main body (e.g., a controller) of the corresponding vehicle. [Explanation of symbols]

[0068] 1 Control device 2 Steering wheel 10 Rim section 11 Grip determination section 12 Operation judgment section 13. Communications Department 20. Touchpad 21 Grasping Sensor 100 Steering wheel device

Claims

1. A steering wheel (2) having a touch pad (20) operable using capacitance and a grip sensor (21) for detecting whether a driver is gripping a rim portion (10); an operation determination unit (12) for determining whether the touch pad (20) is being operated; a grip determination unit (11) that performs a grip determination as to whether the rim portion (10) of the steering wheel (2) is gripped, When the operation determination unit (12) determines that the touch pad (20) is being operated, it transmits a first operation determination signal to the grip determination unit (11), When the first operation determination signal is received, the grip determination unit (11) interrupts the grip determination.

2. The occupant state detection device (100) according to claim 1, characterized in that the touch pad (20) is provided in an area extending from a central portion of the steering wheel (2) to a spoke portion (3).

3. The occupant condition detection device (100) according to claim 1 or 2, wherein the grip determination portion (11) is provided on the steering wheel (2).

4. The occupant condition detection device (100) according to any one of claims 1 to 3, wherein the operation determination unit (12) is provided on the steering wheel (2).

5. When the operation determination unit (12) determines that the touchpad (20) has not been operated after transmitting the first operation determination signal, the operation determination unit (12) transmits a second operation determination signal to the grip determination unit (11); The occupant state detection device (100) according to claim 1, wherein, when the second operation determination signal is received, the grip determination unit (11) resumes the grip determination.

6. The occupant state detection device (100) according to claim 1 or 5, wherein, when the first operation determination signal is received, the grip determination unit (11) determines that the rim portion (10) is being gripped.

7. The occupant state detection device (100) according to any one of claims 1 to 6, wherein the grip determination unit (11) and the operation determination unit (12) are provided on the steering wheel (2).

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