Steering device

Abstract

A steering device (1) is provided with: a steering handle (2); and a sensor unit (62) that detects contact or proximity of a human body with the steering handle, the sensor unit (62) including a plurality of electrodes (60) provided on the steering handle (2), and a plurality of correction electrodes (60d) for correcting capacitance values based on the plurality of electrodes (60), the correction electrodes (60d) being disposed so as to correspond to the surfaces of the plurality of electrodes (60), respectively.

Description

Technical Field

[0001] The present invention relates to a steering device for detecting whether an occupant is holding it. Background Art

[0002] There is known a technique (for example, see Patent Document 1) in which a capacitive virtual sensor is provided near a touch sensor in a device that determines the presence or absence of touch using a capacitive touch sensor. By determining the presence or absence of touch based on the detection values of the touch sensor and the virtual sensor, false detection caused by accidental contact and external radio wave noise is prevented.

[0003] However, in the prior art, false detection is likely to occur due to differences in the installation environments between the touch sensor and the virtual sensor. For example, the capacitance sometimes varies with temperature, and this is particularly problematic in a vehicle interior environment where temperature changes easily occur.

[0004] The invention of the present application improves traffic safety by suppressing the influence caused by differences in the installation environments of the touch sensor and the virtual sensor and appropriately detecting the driver's grip on the steering wheel. Thereby, it is possible to contribute to the development of a sustainable transportation system.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2015-53123 (JP2015-053123A). Summary of the Invention

[0008] One aspect of the present invention is a steering device including a steering wheel and a sensor unit that detects contact or proximity of a human body to the steering wheel. The sensor unit includes: a plurality of electrodes provided on the steering wheel; and a plurality of correction electrodes for correcting capacitance values based on the plurality of electrodes and arranged in a manner corresponding to the surfaces of the plurality of electrodes. Brief Description of the Drawings

[0009] The object, features, and advantages of the present invention are further clarified by the following description of embodiments in relation to the drawings.

[0010] Figure 1 It is a diagram illustrating the structure of a steering device according to an embodiment of the invention and a safe driving assistance system including the steering device.

[0011] Figure 2 It is a schematic diagram illustrating the grip detection range of the electrodes.

[0012] Figure 3 It is a diagram illustrating the circuit structure of the sensor unit.

[0013] Figure 4A is a schematic diagram of the electrode on the right side of Figure 1 .

[0014] Figure 4B is a schematic diagram of the unfolded Figure 4A electrode.

[0015] Figure 5 is a diagram showing the main part structure of the controller included in the sensor unit. Detailed Embodiment

[0016] Hereinafter, embodiments of the invention will be described with reference to the drawings.

[0017] <System Structure>

[0018] Figure 1 is a diagram illustrating the structure of the steering device 1 of the embodiment and the safe driving assistance system 9 including the steering device 1.

[0019] The safe driving assistance system 9 includes a steering device 1 mounted on a vehicle (not shown) and a control device group 8 communicably connected to the steering device 1. By using the steering device 1 and the control device group 8, the safe driving of the vehicle by the driver is assisted.

[0020] In the embodiment, each of the devices 81 to 84 constituting the control device group 8 is described as an in-vehicle device capable of communicating with the steering device 1 through CAN communication using, for example, a CAN (Controller Area Network) bus 80. However, all or part of the plurality of devices 81 to 84 constituting the control device group 8 may be configured as an out-of-vehicle device capable of wirelessly communicating with the steering device 1 via an in-vehicle communication device (not shown).

[0021] <Outline of Steering Device>

[0022] The steering device 1 includes: a steering handle 2 that receives a steering operation of the vehicle and an auxiliary operation of vehicle accessories performed by the driver; a steering shaft 3 that axially supports the steering handle 2; and a grip detection device 6 that detects the grip of the steering handle 2 by the driver. The auxiliary operation includes operations on a navigation device, an audio device, an air conditioner, a multi-information display, etc., and operations on a driving assistance device. The driving assistance device includes, for example, LKAS (Lane Keep Assistant System) and ACC (Adaptive Cruise Control).

[0023] The steering handle 2 includes: a rim portion 20 that is, for example, circular and can be gripped by the driver, a hub portion 23 provided inside the rim portion 20, and three spoke portions 25L, 25R, and 25D that extend radially from the hub portion 23 and are connected to the inner circumferential portion 21 of the rim portion 20.

[0024] The hub portion 23 is disc-shaped and is provided, for example, at the center of the rim portion 20 as viewed from the driver's seat, forming the center of the steering handle 2. A steering shaft 3 that axially supports the steering handle 2 is connected to the back side of the hub portion 23 as viewed from the driver's seat. The steering shaft 3 is a shaft-shaped connecting member that connects the core that forms the framework of the hub portion 23 and a steering mechanism that is a part of the vehicle body (not shown). Therefore, the steering torque generated by the driver rotating the steering handle 2 is transmitted to the above-described steering mechanism via the steering shaft 3.

[0025] The rim portion 20 and the hub portion 23 are connected by three spoke portions 25L, 25R, and 25D. The left spoke portion 25L extends in the horizontal direction and connects the left portion of the hub portion 23 as viewed from the driver's seat in the front view and the left spoke connection portion 26L, which is the left portion of the inner circumferential portion 21 of the rim as viewed from the driver's seat in the front view. The right spoke portion 25R extends in the horizontal direction parallel to the left spoke portion 25L and connects the right portion of the hub portion 23 as viewed from the driver's seat in the front view and the right spoke connection portion 26R, which is the right portion of the inner circumferential portion 21 of the rim as viewed from the driver's seat in the front view. The lower spoke portion 25D is orthogonal to each of the spoke portions 25L and 25R and extends in the vertical direction, connecting the lower portion of the hub portion 23 as viewed from the driver's seat in the front view and the lower portion of the inner circumferential portion 21 of the rim as viewed from the driver's seat in the front view.

[0026] As Figure 1 shown, a concave left thumb catch portion 27L is formed radially outward in the front view at a portion connected to the upper part of the left spoke connection portion 26L of the inner circumferential portion 21 of the rim as viewed from the driver's seat. In addition, a concave right thumb catch portion 27R is formed radially outward in the front view at a portion connected to the upper part of the right spoke connection portion 26R of the inner circumferential portion 21 of the rim as viewed from the driver's seat.

[0027] In the steering device 1 of the embodiment, with the left thumb caught in the left thumb catch portion 27L and the root of the left thumb in contact with the left spoke connection portion 26L, the posture of gripping the rim portion 20 with the remaining fingers of the left hand is defined as the recommended gripping posture for the driver's left hand. Therefore, the recommended gripping position for the driver's left hand is determined at the portion of the rim portion 20 that includes the left spoke connection portion 26L.

[0028] In addition, in the steering device 1 of the embodiment, with the thumb of the right hand caught in the right thumb locking portion 27R and the root of the thumb of the right hand in contact with the right spoke connecting portion 26R, the posture of holding the rim portion 20 with the remaining fingers of the right hand is defined as the recommended holding posture for the driver's right hand. Therefore, the recommended holding position for the driver's right hand is determined in the portion of the rim portion 20 that includes the right spoke connecting portion 26R.

[0029] A left auxiliary operation console unit 5L and a right auxiliary operation console unit 5R for receiving auxiliary operation by the driver for operating an unillustrated vehicle auxiliary machine or the like are provided in the left spoke portion 25L and the right spoke portion 25R, respectively. These left and right auxiliary operation console units 5L and 5R are each substantially rectangular in shape when viewed from the driver. The driver can operate the vehicle auxiliary machine or the like by operating a plurality of switches provided on the left and right auxiliary operation console units 5L and 5R with fingers.

[0030] It should be noted that the left auxiliary operation console unit 5L and the right auxiliary operation console unit 5R may also be referred to as a left functional switch portion and a right functional switch portion, respectively.

[0031] In addition, in the following description, the positions of the rim portion 20, the inner peripheral portion 21 of the rim, the hub portion 23, and the steering shaft 3, which are substantially circular when viewed from the driver, and the orientations of the respective spoke portions 25L, 25R, 25D may be represented by an angle "deg" that rotates clockwise with the steering shaft 3 as the center and with the position of the upper end portion 20C of the rim portion 20 in the front view observed from the driver's seat as a reference. That is, the right spoke portion 25R extends in the direction of 90 deg and connects the hub portion 23 and the 90 deg portion of the inner peripheral portion 21 of the rim. The lower spoke portion 25D extends in the direction of 180 deg and connects the hub portion 23 and the 180 deg portion of the inner peripheral portion 21 of the rim. In addition, the left spoke portion 25L extends in the direction of 270 deg and connects the hub portion 23 and the 270 deg portion of the inner peripheral portion 21 of the rim. When represented by the above clockwise rotation angle "deg", the recommended holding position for the driver's left hand is determined at the 270 deg position of the rim portion 20. In addition, the recommended holding position for the driver's right hand is determined at the 90 deg position of the rim portion 20.

[0032] <Grip Detection Device>

[0033] As an example, the grip detection device 6 includes an electrode 60 provided on the steering handle 2 and a sensor unit 62 electrically connected to the electrode 60. Hereinafter, the eight electrodes, i.e., the first left electrode 60L1, the second left electrode 60L2, the third left electrode 60L3, the fourth left electrode 60L4, the first right electrode 60R1, the second right electrode 60R2, the third right electrode 60R3, and the fourth right electrode 60R4, may be collectively referred to as the electrode 60.

[0034] Each of the eight electrodes constituting the electrode 60 is configured as a conductive plate. The first left electrode 60L1, the second left electrode 60L2, the third left electrode 60L3, and the fourth left electrode 60L4 are provided near the recommended gripping position of the left hand with respect to the rim portion 20 in the steering handle 2. More specifically, the first left electrode 60L1 and the second left electrode 60L2 are provided by observing from the driver along the upper side and the radially outer side wall surface of the left auxiliary operation console unit 5L at the left spoke portion 25L (more specifically, the end face of a printed circuit board (which may also be referred to as an electronic substrate) not shown disposed within the left auxiliary operation console unit 5L).

[0035] In addition, the third left electrode 60L3 and the fourth left electrode 60L4 are provided by observing from the driver along the lower side of the left auxiliary operation console unit 5L (more specifically, the end face of the above-mentioned printed circuit board) and the surface opposed to the rim portion 20 at the lower left side portion in the hub portion 23 at the left spoke portion 25L.

[0036] Similarly, the first right electrode 60R1, the second right electrode 60R2, the third right electrode 60R3, and the fourth right electrode 60R4 are provided near the recommended gripping position of the right hand with respect to the rim portion 20 in the steering handle 2. More specifically, the first right electrode 60R1 and the second right electrode 60R2 are provided by observing from the driver along the upper side and the radially outer side wall surface of the right auxiliary operation console unit 5R at the right spoke portion 25R (more specifically, the end face of the printed circuit board disposed within the right auxiliary operation console unit 5R).

[0037] In addition, the third right electrode 60R3 and the fourth right electrode 60R4 are provided by observing from the driver along the lower side of the right auxiliary operation console unit 5R (more specifically, the end face of the above-mentioned printed circuit board) and the surface opposed to the rim portion 20 at the lower right side portion in the hub portion 23 at the right spoke portion 25R.

[0038] The first left electrode 60L1, the second left electrode 60L2, the third left electrode 60L3, and the fourth left electrode 60L4 among the above eight electrodes can also be integrally arranged on the base substrate in their respective insulated states. Similarly, the first right electrode 60R1, the second right electrode 60R2, the third right electrode 60R3, and the fourth right electrode 60R4 can also be integrally arranged on the base substrate in their respective insulated states.

[0039] <Sensor Unit>

[0040] The sensor unit 62 includes eight sensor units 62L1, 62L2, 62L3, 62L4, 62R1, 62R2, 62R3, and 62R4 corresponding to the above eight electrodes 60L1, 60L2, 60L3, 60L4, 60R1, 60R2, 60R3, and 60R4. The sensor unit 62L1 is connected to the first left electrode 60L1 via the left wiring 61L1. The sensor unit 62L2 is connected to the second left electrode 60L2 via the left wiring 61L2. The sensor unit 62L3 is connected to the third left electrode 60L3 via the left wiring 61L3. The sensor unit 62L4 is connected to the fourth left electrode 60L4 via the left wiring 61L4.

[0041] In addition, the sensor unit 62R1 is connected to the first right electrode 60R1 via the right wiring 61R1. The sensor unit 62R2 is connected to the second right electrode 60R2 via the right wiring 61R2. The sensor unit 62R3 is connected to the third right electrode 60R3 via the right wiring 61R3. The sensor unit 62R4 is connected to the fourth right electrode 60R4 via the right wiring 61R4.

[0042] The sensor units 62L1 to 62L4 are provided, for example, inside the left wheel spoke portion 25L together with the above-mentioned left auxiliary operation console unit 5L. In addition, the sensor units 62R1 to 62R4 are provided inside the right wheel spoke portion 25R together with the above-mentioned right auxiliary operation console unit 5R.

[0043] <Grip Detection Range>

[0044] Figure 2 It is a schematic diagram illustrating the grip detection ranges RL1 to RL4 and RR1 to RR4 of the electrodes 60 (60L1 to 60L4 and 60R1 to 60R4) as described above. In each of the grip detection ranges RL1 to RL4 and RR1 to RR4, by applying a prescribed voltage to the corresponding electrodes 60 (60L1 to 60L4 and 60R1 to 60R4), electric field lines are triggered from these respective electrodes 60 (60L1 to 60L4 and 60R1 to 60R4).

[0045] In an embodiment, as described above, the first left electrode 60L1 and the second left electrode 60L2 are provided near the recommended gripping position (270 deg) of the rim portion 20 for the left hand in the left spoke portion 25L, and the third left electrode 60L3 and the fourth left electrode 60L4 are provided near the recommended gripping position (270 to 180 deg) of the rim portion 20 for the left hand in the hub portion 23.

[0046] With such a configuration, the gripping detection ranges RL1 and RL2 (330 deg to 260 deg) correspond to the first left electrode 60L1 and the second left electrode 60L2, and the gripping detection ranges RL3 and RL4 (260 deg to 210 deg) correspond to the third left electrode 60L3 and the fourth left electrode 60L4.

[0047] Similarly, the first right electrode 60R1 and the second right electrode 60R2 are provided near the recommended gripping position (90 deg) of the rim portion 20 for the right hand in the right spoke portion 25R, and the third right electrode 60R3 and the fourth right electrode 60R4 are provided near the recommended gripping position (90 to 180 deg) of the rim portion 20 for the right hand in the hub portion 23.

[0048] With such a configuration, the gripping detection ranges RR1 and RR2 (30 deg to 100 deg) correspond to the first right electrode 60R1 and the second right electrode 60R2, and the gripping detection ranges RR3 and RR4 (100 deg to 150 deg) correspond to the third right electrode 60R3 and the fourth right electrode 60R4.

[0049] <Circuit Structure Example>

[0050] Figure 3 FIG. is a diagram illustrating the circuit structure of the sensor unit 62R1 in the gripping detection device 6. Although not shown, the circuit structures of the other sensor units 62L1 to 62L4 and 62R2 to 62R4 other than the sensor unit 62R1 are the same.

[0051] The sensor unit 62R1 measures the electrical characteristics of the first right electrode 60R1 (for example, the capacitance between the first right electrode 60R1 and the ground wire (for example, the vehicle body)), detects the gripping of the steering handle 2 by the driver based on the measurement result, and further estimates the gripping position of the driver on the rim portion 20.

[0052] The sensor unit 62R1 includes a first switch SW1, a pulse power supply 63, an amplifier 64, a control unit 67, a second switch SW2, a charging capacitor 65, a measurement unit 68, and a detection unit 69, and detects the gripping of the steering handle 2 by the driver by using these components.

[0053] It should be noted that inFigure 3 In this case, the electrostatic capacitance between the first right electrode 60R1 and the ground wire is illustrated as the electrostatic capacitance Ch formed by the human body H including the hand of the driver who operates the steering handle 2 and the stray capacitance Ce formed by the stray capacitors E such as wirings and parts other than the human body H.

[0054] As Figure 3 shown, the pulse power supply 63 and the amplifier 64 are connected in series. In addition, the second switch SW2 is connected in parallel with the charging capacitor 65. The series circuit composed of the pulse power supply 63 and the amplifier 64 and the parallel circuit composed of the second switch SW2 and the charging capacitor 65 are connected via the first switch SW1. More specifically, the output terminal of the amplifier 64 and the first right electrode 60R1 are connected via the first switch SW1 and the right wiring 61R1. In addition, the second switch SW2 and the charging capacitor 65 are connected to the first right electrode 60R1 via the first switch SW1 and the right wiring 61R1.

[0055] The pulse power supply 63 supplies a pulse voltage Vs with a specified frequency and voltage to the amplifier 64 according to an instruction from, for example, the control unit 67. The amplifier 64 amplifies the pulse voltage Vs supplied from the pulse power supply 63 and applies it to the first right electrode 60R1 via the first switch SW1 and the right wiring 61R1.

[0056] The second switch SW2 is a switching element such as a transistor that is turned on / off by a drive circuit (not shown) in the control unit 67, for example. As an example, the control unit 67 keeps the second switch SW2 off during the period until the voltage VCref of the charging capacitor 65 reaches a threshold value Vthr of a predetermined voltage, and accumulates charge (which can also be called charging) in the charging capacitor 65. The control unit 67 also turns on the second switch SW2 after the voltage VCref reaches the above threshold value Vthr, and discharges the charge accumulated in the charging capacitor 65.

[0057] The first switch SW1 is a switching element whose switching is controlled by a drive circuit (not shown) in the control unit 67, for example, and includes, as an example, an FET (Field Effect Transistor). In the embodiment, it has a terminal t1 for connecting the first right electrode 60R1 to the charging capacitor 65, a terminal t2 for connecting the first right electrode 60R1 and the amplifier 64, and a terminal t3 for connecting the first right electrode 60R1 and the ground wire.

[0058] The ground wire is equipotential with the GND pattern of the PCB (Printed Circuit Board) of the circuit forming the sensor unit 62R1 other than the first right electrode 60R1, and is arranged substantially parallel to at least one of the wiring pattern to the terminal t1 and the wiring pattern to the terminal t2. In Figure 3 the ground wire is shown in parallel with the wiring pattern to the terminal t2.

[0059] By arranging the ground wire (GND pattern) near the signal wire (the wiring pattern to the terminal t2), the electromagnetic coupling between the signal wire and the ground wire can be enhanced, and the coupling between the signal wire and other patterns on the PCB can be suppressed. In other words, it suppresses the transfer of signals of other patterns on the PCB as noise to the signal wire due to leakage current flowing on the PCB surface, etc., and conversely, the transfer of the signal of the signal wire as noise to other patterns on the PCB.

[0060] The first switch SW1, according to an instruction from the control unit 67, selects the terminal t1 of the first switch SW1 in response to the rise of the pulse voltage Vs of the pulse power supply 63. Thus, the first right electrode 60R1 and the amplifier 64 are connected via the first switch SW1 and the right wiring 61R1, and the pulse voltage supplied from the pulse power supply 63 and the amplifier 64 is applied to the first right electrode 60R1 to charge the human body H and the floating capacitor E.

[0061] Next, the first switch SW1, according to an instruction from the control unit 67, selects the terminal t2 of the first switch SW1 in response to the fall of the pulse voltage Vs of the pulse power supply 63. Thus, the first right electrode 60R1 and the charging capacitor 65 are connected via the first switch SW1 and the right wiring 61R1, and the charge stored in the human body H and the floating capacitor E moves to the charging capacitor 65 to charge the charging capacitor 65. As a result, the voltage VCref of the charging capacitor 65 rises.

[0062] In this way, when the pulse voltage is repeatedly applied to the first right electrode 60R1 by the pulse power supply 63 and the amplifier 64, the charging and discharging of the human body H and the floating capacitor E are alternately repeated, and the voltage VCref of the charging capacitor 65 gradually increases. At this time, the time until the voltage VCref of the charging capacitor 65 reaches a predetermined voltage threshold Vthr (which can also be represented by the number of pulses of the pulse power supply 63) varies according to the electrostatic capacitance Ch formed by the human body H, that is, the relative position of the hand of the driver operating the steering wheel 2 with respect to the first right electrode 60R1. That is, when the driver's hand holds the grip detection range RR1 in the rim portion 20 (refer to Figure 2) When the capacitance Ch is large in the part within , the time required for the voltage VCref of the charging capacitor 65 to reach the threshold Vthr is shortened. When the driver's hand leaves the grip detection range RR1 and the capacitance Ch is small, the time required for the voltage VCref of the charging capacitor 65 to reach the voltage threshold Vthr is extended.

[0063] Furthermore, according to an instruction from the control unit 67, the first switch SW1 selects the terminal t3 of the first switch SW1 at a prescribed timing. As a result, the first right electrode 60R1 and the ground line are connected via the first switch SW1 and the right wiring 61R1, and the charges stored in the human body H and the floating capacitor E and the charges remaining in the first right electrode 60R1 and the right wiring 61R1 are discharged to the ground line.

[0064] For example, when the control unit 67 selects the terminal t1 of the first switch SW1 and when it selects the terminal t2 of the first switch SW1, the control unit 67 outputs an instruction to the first switch SW1 so that the terminal t1 and the terminal t2 are selected after temporarily selecting the terminal t3, respectively.

[0065] In addition, the control unit 67 can also output an instruction to the first switch SW1 to select the terminal t3 of the first switch SW1 in coordination with the timing of turning on the second switch SW2 (in other words, discharging the charges stored in the charging capacitor 65).

[0066] Furthermore, an instruction can also be output to the first switch SW1 to select the terminal t3 of the first switch SW1 in coordination with the timing of other auxiliary machine operations, etc.

[0067] The timing of selecting the terminal t3 of the first switch SW1 is configured to be appropriately changeable according to the program executed by the control unit 67.

[0068] The measuring unit 68 measures the electrostatic capacitance Ch formed by the human body H. More specifically, the measuring unit 68 includes a detector (not shown) that detects the voltage VCref of the charging capacitor 65. The measuring unit 68 measures the time and the number of pulses until the voltage VCref reaches the threshold Vthr based on the detection value of the detector. The measuring unit 68 indirectly measures the electrostatic capacitance Ch formed by the human body H present near the first right electrode 60R1 based on the measurement result. The measuring unit 68 outputs the measured value Ch_d of the electrostatic capacitance Ch obtained through the above steps to the detection unit 69.

[0069] The detection unit 69 detects the driver's grip on the rim portion 20 based on the capacitance measurement value Ch_d of the measurement unit 68, and estimates the grip position on the rim portion 20 when the grip on the rim portion 20 is detected. The larger the value of the capacitance measurement value Ch_d when the grip is detected, the closer the detection unit 69 estimates the grip position on the rim portion 20 to the right spoke portion 25R (e.g., 100 deg); the smaller the value of the capacitance measurement value Ch_d when the grip is detected, the farther the detection unit 69 estimates the grip position on the rim portion 20 from the right spoke portion 25R (e.g., 150 deg).

[0070] As described above, the detection unit 69 of the sensor unit 62R1 detects the driver's grip in the grip detection range RR1 of the rim portion 20 based on the measurement value Ch_d of the electrostatic capacitance Ch formed by the human body H existing near the first right electrode 60R1, and estimates the grip position on the rim portion 20.

[0071] It should be noted that although the description is omitted, the detection of the grip in the grip detection range RR2 of the rim portion 20 by the sensor unit 62R2 and the estimation of the grip position, the detection of the grip in the grip detection range RR3 of the rim portion 20 by the sensor unit 62R3 and the estimation of the grip position, and the detection of the grip in the grip detection range RR4 of the rim portion 20 by the sensor unit 62R4 and the estimation of the grip position are the same as the detection of the grip in the grip detection range RR1 of the rim portion 20 by the above-described sensor unit 62R1 and the estimation of the grip position.

[0072] In addition, the detection of the grip in the grip detection ranges RL1 to RL4 of the rim portion 20 by the sensor units 62L1 to 62L4 and the estimation of the grip position are the same as the detection of the grip in the grip detection range RR1 of the rim portion 20 by the above-described sensor unit 62R1 and the estimation of the grip position.

[0073] <Details of Capacitance Measurement>

[0074] The capacitance measurement of the electrostatic capacitance Ch will be further described in detail. The above-described sensor unit 62R1 detects the electrostatic capacitance based on the voltage VCref of the charging capacitor 65 charged by the charges from the human body H and the floating capacitor E. Therefore, the measurement value of the electrostatic capacitance measured by the sensor unit 62R1 (in the following description, sometimes referred to as the capacitance value) includes both the electrostatic capacitance Ch of the human body H and the stray capacitance Ce of the floating capacitor E.

[0075] The measurement unit 68 performs the following processing to exclude the portion corresponding to the stray capacitance Ce from the measured capacitance value (in other words, extract the electrostatic capacitance Ch portion). In the following description, the portion corresponding to the stray capacitance Ce is referred to as the capacitance basic value.

[0076] The sensor unit 62R1 is normally controlled to measure the capacitance value n at each prescribed time (e.g., 10 msec). Based on the capacitance value n measured in a state where the driver does not hold the steering handle 2, the measurement unit 68 calculates the latest capacitance basic value n using the following formula (1).

[0077] Capacitance basic value n = (capacitance value n + WT × capacitance basic value (n - 1)) / (WT + 1) (1)

[0078] Note that the capacitance value n is the capacitance value measured by the sensor unit 62R1. In a state where the driver does not hold the steering handle 2, the capacitance value n represents the value of the portion corresponding to the stray capacitance Ce. The symbol WT represents a prescribed weighting factor. The capacitance basic value (n - 1) represents the capacitance basic value calculated using formula (1) in the previous calculation (10 msec ago).

[0079] Through the above formula (1), weighted calculation is performed using the latest capacitance value n and the previous capacitance basic value (n - 1) obtained by weighting. Therefore, when the latest capacitance value n changes from the previous value due to a change in the electrode installation environment, the latest capacitance basic value n can be calculated in such a way that it does not change significantly from the previous capacitance basic value (n - 1).

[0080] The measurement unit 68 measures the capacitance value n and calculates the capacitance basic value n at each of the above - mentioned prescribed time intervals, and calculates the latest capacitance difference value n using the following formula (2).

[0081] Capacitance difference value n = capacitance value n - capacitance basic value n (2)

[0082] Note that the capacitance value n represents the latest capacitance value measured by the sensor unit 62R1. The capacitance basic value n represents the latest capacitance basic value calculated using the above formula (1).

[0083] When the latest capacitance difference value n calculated using the above formula (2) is less than a predetermined prescribed determination threshold value, the measurement unit 68 determines that the driver does not hold the steering handle 2, and repeats the measurement of the capacitance value n, the calculation of the capacitance basic value n, and the calculation of the capacitance difference value n using the above formula (2) in units of the above - mentioned prescribed time.

[0084] When the most recent capacitance difference n calculated using the above formula (2) exceeds a predetermined determination threshold, the measurement unit 68 determines that the steering handle 2 may have been held by the driver and stops calculating the capacitance basic value. Then, the measurement of the capacitance value n is repeated in units of the above-mentioned predetermined time, and the capacitance difference n using the following formula (3) is calculated.

[0085] Capacitance difference n = capacitance value n - capacitance basic value p (3)

[0086] It should be noted that the capacitance value n represents the most recent capacitance value measured by the sensor unit 62R1. When the steering handle 2 is in the state of being held by the driver, the capacitance value n represents the value of both the static capacitance Ch of the human body H and the stray capacitance Ce of the floating capacitor E. The capacitance basic value p represents the past capacitance basic value finally calculated using the above formula (1).

[0087] When the most recent capacitance difference n calculated using the above formula (3) is less than a predetermined determination threshold, the measurement unit 68 determines that the driver is not holding the steering handle 2 and restarts calculating the capacitance basic value n.

[0088] Then, in units of the above-mentioned predetermined time, the measurement of the capacitance value n, the calculation of the capacitance basic value n, and the calculation of the capacitance difference n using the above formula (2) are repeated.

[0089] The measurement unit 68 sends the capacitance difference n calculated using the above formula (2) or formula (3) to the detection unit 69 as the measured value Ch_d of the static capacitance Ch.

[0090] <Measures for changes in measured values>

[0091] In the embodiment, for example, in the sensor unit 62R1, due to the installation environment (especially temperature and humidity) of the first right electrode 60R1, the voltage VCref of the above-mentioned charging capacitor 65 changes. Specifically, as the environment such as temperature changes, the stray capacitance Ce of the floating capacitor E changes, and thus the voltage VCref of the charging capacitor 65 changes. The change in the voltage VCref also affects the measured value Ch_d of the static capacitance Ch.

[0092] In order to suppress the influence of temperature, etc. on the measured value Ch_d of the static capacitance Ch, the measurement unit 68 corrects the capacitance basic value p of the above formula (3) as follows and calculates the capacitance difference n.

[0093] Figure 4A is extracted Figure 1Schematic diagram of the first right electrode 60R1, the second right electrode 60R2, the third right electrode 60R3, and the fourth right electrode 60R4 among the above eight electrodes 60L1, 60L2, 60L3, 60L4, 60R1, 60R2, 60R3, and 60R4.

[0094] The four electrodes 60R1, 60R2, 60R3, and 60R4 are arranged such that, when observed from the driver, they face the rim portion 20 at the upper and radially outer side wall surface along the right spoke portion 25R above the right auxiliary machine operation control console unit 5R, and at the lower right side portion in the hub portion 23 below the right auxiliary machine operation control console unit 5R.

[0095] Figure 4B Is expanded in Figure 4A Schematic diagram of the four electrodes 60R1, 60R2, 60R3, and 60R4 illustrated in. Along the conductive plate-like electrode surface of each of the electrodes 60R1, 60R2, 60R3, and 60R4, conductive linear virtual electrodes 60R1d, 60R2d, 60R3d, and 60R4d are respectively arranged in a state insulated from each of the electrodes 60R1, 60R2, 60R3, and 60R4. More specifically, when observed with the longitudinal direction of each electrode as the horizontal direction, the virtual electrodes 60R1d, 60R2d, 60R3d, and 60R4d are arranged in a direction crossing the surfaces of the electrodes 60R1, 60R2, 60R3, and 60R4.

[0096] Compared with the corresponding four electrodes 60R1, 60R2, 60R3, and 60R4, the surface areas of the virtual electrodes 60R1d, 60R2d, 60R3d, and 60R4d are small (for example, one percent respectively). Therefore, it is difficult to measure the capacitance value based on the charge stored in the human body H using the virtual electrodes. However, the trend of the change in the capacitance value (corresponding to the above capacitance basic value n) based on the charge stored in the floating capacitor E due to the setting environment of the virtual electrodes can be grasped.

[0097] For example, it is considered that the first right electrode 60R1 and the virtual electrode 60R1d corresponding to the first right electrode 60R1 are in the same setting environment. Then, when the capacitance value corresponding to the stray capacitance Ce portion measured based on the charge moving from the first right electrode 60R1 changes due to the setting environment, it is presumed that the capacitance value corresponding to the stray capacitance Ce portion measured based on the charge moving from the corresponding virtual electrode 60R1d also changes due to the setting environment.

[0098] After the measurement unit 68 stops calculating the capacitance basic value n because the most recent capacitance difference value n calculated using the above formula (2) exceeds a predetermined determination threshold value, and then repeats the measurement of the capacitance value n and the calculation of the capacitance difference value n using the above formula (3) at a predetermined time interval, in parallel with the measurement of the capacitance value n, the measurement of the capacitance value (referred to as the virtual capacitance value dn) based on the charge moving from the virtual electrode is repeated in units of the above predetermined time.

[0099] Then, when there is a change in the virtual capacitance value dn (when the change from the previous (10 msec ago) measurement value is more than a predetermined value), the capacitance basic value p is corrected using the correction value Δ×α obtained by multiplying the change amplitude Δ by a predetermined coefficient α (corresponding to the surface area ratio of the virtual electrode and the corresponding electrode, which is 100 in the above example). For example, when it has increased compared to the previous measurement value, the corrected capacitance basic value (p + Δ×α) obtained by adding the correction value Δ×α to the previous capacitance basic value p is used, and the capacitance difference value n is calculated using the above formula (3). On the other hand, when it has decreased compared to the previous measurement value, the corrected capacitance basic value (p - Δ×α) obtained by subtracting the correction value Δ×α from the previous capacitance basic value p is used, and the capacitance difference value n is calculated using the above formula (3).

[0100] Thus, during the period when the calculation of the capacitance basic value n is stopped, even when the stray capacitance Ce of the floating capacitor E changes due to environmental changes such as temperature, the corrected capacitance basic value (p ± Δ×α) corrected using the change amplitude of the virtual capacitance value dn can be used to appropriately calculate the capacitance difference value n (i.e., the electrostatic capacitance Ch of the human body H).

[0101] In the above description, the sensor unit 62R1 is taken as an example to represent the eight sensor units 62L1 to 62L4 and 62R1 to 62R4, but the same applies when the electrostatic capacitance Ch is measured by other sensor units 62R2 to 62R4 and 62L1 to 62L4. It should be noted that the weight value WT in the above formula (1), the predetermined determination threshold value, etc. compared with the capacitance difference value n calculated using the above formulas (2) and (3) can be appropriately changed for each sensor unit.

[0102] <Main Structure of the Controller>

[0103] Figure 5 This is a diagram showing the main structure of the controller 620 including the sensor unit 62 having the sensor units 62L1, 62L2, 62L3, 62L4, 62R1, 62R2, 62R3, and 62R4. As Figure 5As shown, the controller 620 is composed of a computer having an arithmetic unit such as a CPU (microprocessor), and storage units 622 such as a ROM (read-only memory) and a RAM (random access memory). By executing a program stored in the storage unit 622, the arithmetic unit 621 functions as Figure 3 the control unit 67, the measurement unit 68 (excluding the above-mentioned detector), and the detection unit 69. That is, the arithmetic unit 621 has Figure 3 the control unit 67, the measurement unit 68, and the detection unit 69 as functional structures. It should be noted that the arithmetic unit 621 may have separate control units 67, measurement units 68, and detection units 69 for the sensor units 62L1, 62L2, 62L3, 62L4, 62R1, 62R2, 62R3, and 62R4, or may have a common control unit 67, measurement unit 68, and detection unit 69.

[0104] By adopting the above-described embodiment, the following effects are obtained.

[0105] (1) The steering device 1 includes: a steering handle 2; and a sensor unit 62 that detects contact or proximity of a human body to the steering handle 2. The sensor unit 62R1 includes a plurality of electrodes 60 (e.g., 60R1 to 60R4) provided on the steering handle 2 and respective virtual electrodes 60d (e.g., 60R1d to 60R4d) that are arranged on the surfaces of the respective electrodes 60R1 to 60R4 as a plurality of correction electrodes for correcting capacitance values based on the respective electrodes 60R1 to 60R4.

[0106] With such a configuration, it is possible to appropriately detect the gripping of the steering handle 2. Specifically, since it is considered that the respective virtual electrodes 60R1d to 60R4d are in substantially the same installation environment as the respective electrodes 60R1 to 60R4, when the capacitance values based on the respective electrodes 60R1 to 60R4 change due to temperature or the like, it is possible to correct the capacitance values based on the respective electrodes 60R1 to 60R4 according to the change in the capacitance values of the respective virtual electrodes 60R1d to 60R4d. Thereby, it is possible to perform gripping detection of the steering handle 2 that conforms to the characteristics of the respective sensor units 62 each including the respective electrodes 60R1 to 60R4.

[0107] (2) The respective virtual electrodes 60R1d to 60R4d are arranged along the surfaces of the respective electrodes 60R1 to 60R4 in the longitudinal direction.

[0108] Because of such a configuration, it is possible to arrange the respective longer virtual electrodes 60R1d to 60R4d along the surfaces of the respective electrodes 60R1 to 60R4. Thereby, the respective virtual electrodes 60R1d to 60R4d can be arranged in a manner that can be regarded as being in substantially the same installation environment as the respective electrodes 60R1 to 60R4. Therefore, it is possible to perform the gripping detection of the steering handle 2 that conforms to the characteristics of the respective sensor units 62 each including the respective electrodes 60R1 to 60R4.

[0109] (3) The respective virtual electrodes 60R1d to 60R4d are each formed in a linear shape along the surfaces of the respective electrodes 60R1 to 60R4.

[0110] Because of such a configuration, the areas of the respective virtual electrodes 60R1d to 60R4d are suppressed to be small (for example, one percent as described above). Thereby, the respective virtual electrodes 60R1d to 60R4d can be arranged in a manner that suppresses the influence on the respective electrodes 60R1 to 60R4. In addition, by making the areas of the respective virtual electrodes 60R1d to 60R4d smaller, that is, by configuring the respective virtual electrodes 60R1d to 60R4d in a manner that makes it difficult to measure the capacitance value based on the charge stored in the human body, the respective virtual electrodes 60R1d to 60R4 can accurately detect the change in the capacitance value (corresponding to the above-mentioned basic capacitance value n) based on the charge stored in the floating capacitor E due to the installation environment. By correcting the capacitance value based on the respective electrodes 60R1 to 60R4 according to the change in the capacitance value of the respective virtual electrodes 60R1d to 60R4d configured in this way, it is possible to accurately detect the gripping of the steering handle 2 even when the stray capacitance Ce of the floating capacitor E changes due to environmental changes such as temperature.

[0111] (4) The steering handle 2 includes: an annular rim portion 20, a hub portion 23 provided inside the rim portion 20, and respective spoke portions 25L, 25R, 25D that extend radially from the hub portion 23 to connect the hub portion 23 and the inner peripheral portion 21 of the rim portion 20. For example, the sensor unit 62R1 is arranged in a right auxiliary machine operation control console unit (right functional switch portion) 5R provided in the right spoke portion 25R.

[0112] Generally speaking, it is easier to ensure that the space inside the spoke portion is larger than the space inside the rim portion. Therefore, by adopting the structure as described in the above (4), compared with the case where the sensor unit is insert-molded inside the rim portion of the steering wheel, the production technical ability can be improved.

[0113] (5) Each of the spoke portions 25L, 25R, and 25D is provided between the rim portion 20 held by the occupant and the hub portion 23. For example, the sensor units 62L1 to 62L4 and 62R1 to 62R4 are respectively provided in the left spoke portion 25L and the right spoke portion 25R in the front view observed from the driver's seat among the plurality of spoke portions 25L, 25R, and 25D, and are arranged close to switches and the like as structural parts for performing at least one of vehicle information operation or driving assistance function operation within the left auxiliary machine operation console unit (left function switch portion) 5L and the right auxiliary machine operation console unit (right function switch portion) 5R.

[0114] With such a configuration, by respectively arranging the PCBs of the sensor units 62L1 to 62L4 and 62R1 to 62R4 in the left auxiliary machine operation console unit (left function switch portion) 5L and the right auxiliary machine operation console unit (right function switch portion) 5R that are paired and arranged in the left spoke portion 25L and the right spoke portion 25R, it is possible to appropriately perform the gripping detection within the recommended gripping ranges on the left and right of the rim portion 20.

[0115] The above-described embodiment can be deformed in various ways. The following describes the modification examples.

[0116] (Modification Example 1)

[0117] In the embodiment, the annular steering wheel is illustrated as the steering handle 2, but the present invention can also be applied to the case where a non-annular steering handle having a special shape such as a square shape or a rod shape is used.

[0118] (Modification Example 2)

[0119] In the embodiment, eight electrodes, namely the first left electrode 60L1 to the fourth left electrode 60L4 and the first right electrode 60R1 to the fourth right electrode 60R4, are illustrated as the plurality of electrodes 60, but the number of electrodes can be more or less than eight.

[0120] In addition, corresponding to the illustrated eight electrodes 60L1 to 60L4 and 60R1 to 60R4, eight sensor units 62L1 to 62L4 and 62R1 to 62R4 are illustrated, but the number of sensor units 62 can also be increased or decreased according to the number of electrodes 60.

[0121] Furthermore, in the embodiment, the case where one sensor unit 62 corresponds to one electrode 60 is illustrated, but it is also possible to make a plurality of electrodes 60 correspond to one sensor unit 62. For example, one sensor unit 62 arranged in the left spoke portion 25L on the left side in the front view corresponds to the first left electrode 60L1 to the fourth left electrode 60L4, and another sensor unit 62 arranged in the right spoke portion 25R on the right side in the front view corresponds to the first right electrode 60R1 to the fourth right electrode 60R4.

[0122] In addition, the left and right sensor units 62 can be integrated into one. In the case of integration, the integrated one sensor unit 62 can be arranged in any one of the left wheel spoke part 25L, the right wheel spoke part 25R, and the lower wheel spoke part 25D.

[0123] (Modification Example 3)

[0124] In the embodiment, the measurement unit 68 as the correction unit corrects the capacitance values based on the electrodes 60R1 to 60R4 respectively according to the variation amplitude of the capacitance values of the respective virtual electrodes 60R1d to 60R4d disposed on the surfaces of the electrodes 60R1 to 60R4. However, in the steering device 1, the sensor unit 62 can further constitute the measurement unit 68 as the correction unit, such that in addition to the plurality of virtual electrodes 60R1d to 60R4d, the electrodes among the plurality of electrodes 60R1 to 60R4 provided on the steering handle 2 that do not accumulate charges due to contact or proximity of a human body are used for correcting the capacitance values of the other electrodes where charge accumulation occurs. That is, the correction unit can also correct the capacitance values based on the electrodes where charge accumulation occurs according to the variation amplitude of the capacitance values of the electrodes among the electrodes 60R1 to 60R4 that do not accumulate charges due to contact or proximity of a human body.

[0125] By configuring in this way, the electrodes among the respective electrodes 60R1 to 60R4 that do not accumulate charges due to contact or proximity of a human body can be used to replace the respective virtual electrodes 60R1d to 60R4d. Thereby, the redundancy in the grip detection of the steering handle 2 can be improved.

[0126] (Modification Example 4)

[0127] It is also possible to provide thermistor elements to replace the respective virtual electrodes 60R1d to 60R4d. As a specific example, along the Figure 4B plate-like electrode surfaces of the respective electrodes 60R1, 60R2, 60R3, and 60R4 exemplified, four thermistor elements are respectively arranged in a state insulated from the respective electrodes 60R1, 60R2, 60R3, and 60R4.

[0128] The measurement unit 68 respectively detects the temperature environments of the respective electrodes 60R1, 60R2, 60R3, and 60R4 according to the resistance values of the respective thermistors, and selects a correction coefficient for correction from a plurality of pre-prepared correction coefficients according to the detected temperature. And, using the corrected capacitance basic value (p ± correction coefficient), the capacitance difference n is calculated by the above formula (3).

[0129] By using the modification example 4 described above, during the period when the calculation of the basic capacitance value n is stopped, even when the stray capacitance Ce of the floating capacitor E changes due to environmental changes such as temperature, it is possible to use the corrected capacitance basic value (p ± correction factor) corrected with the correction factor selected according to the change in the resistance value of the thermistor element, and appropriately calculate the capacitance difference n (i.e., the electrostatic capacitance Ch of the human body H).

[0130] The above description is only an example, and the above embodiments and modification examples do not limit the present invention as long as the features of the present invention are not destroyed. It is possible to arbitrarily combine one or more of the above embodiments and modification examples, and it is also possible to combine the modification examples with each other.

[0131] By adopting the present invention, it is possible to appropriately detect the grasping of the steering handle.

[0132] The present invention has been described above in conjunction with the preferred embodiments, but those skilled in the art should understand that various modifications and changes can be made without departing from the scope of disclosure of the claims.

Claims

1. A steering device, comprising a steering handle (2) and a sensor unit (62) for detecting contact or proximity of a human body to the steering handle (2), characterized in that: The sensor unit (62) comprises: A plurality of electrodes (60) disposed on the steering handle (2); and A plurality of correction electrodes (60d) are used to correct the capacitance value based on the plurality of electrodes (60), and are arranged in a manner corresponding to respective surfaces of the plurality of electrodes (60).

2. The steering device according to claim 1, characterized in that: The correction electrodes (60d) are arranged in the longitudinal direction along the surface of the corresponding electrode (60).

3. The steering device according to claim 1, characterized in that: The correction electrode (60d) is formed in a linear shape along the surface of the corresponding electrode (60).

4. The steering device according to claim 1, characterized in that: The sensor unit (62) further includes a calibration unit (68). The correction unit (68) calculates a correction value based on a variation range of the capacitance value based on the plurality of correction electrodes (60d), and uses the correction value to correct the capacitance value based on the plurality of electrodes (60).

5. The steering device according to claim 4, characterized in that: The correction value is a value obtained by multiplying a variation range of the capacitance values ​​of the plurality of correction electrodes (60d) by a predetermined coefficient. The predetermined coefficient is a value based on the ratio of the surface area of ​​the correction electrode (60d) to the surface area of ​​the corresponding electrode (60).

6. The steering device according to claim 1, characterized in that: The steering handle includes an annular rim portion, a hub portion provided inside the rim portion, and a spoke portion extending from the hub portion in a radial direction of the rim portion and connecting the hub portion and the inner peripheral portion of the rim portion. The sensor unit is disposed in a function switch portion provided on the spoke portion.

7. The steering device according to claim 6, characterized in that: The spoke portion is provided in plurality between the rim portion held by the passenger and the hub portion. The sensor unit is respectively arranged on the left spoke and the right spoke in the front view from the driver's seat among the plurality of spokes, and is arranged in the function switch portion close to a structural part for performing at least one of vehicle information operation and driving assistance function operation.

8. The steering device according to claim 4, characterized in that: The correction unit (68) further corrects the capacitance value of the electrode that accumulates the charge among the plurality of electrodes (60) provided on the steering handle (2), based on the amplitude of the variation of the capacitance value of the electrode that does not accumulate the charge due to contact or proximity of the human body among the plurality of electrodes (60) provided on the steering handle (2).

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