Steering device

Abstract

The present invention is to provide a steering device that can reasonably determine whether or not a steering wheel is held regardless of the size of a driver. To solve the above problem, the steering device (1) of the present invention includes: a steering wheel (2) that receives a steering operation of a vehicle by a driver; a plurality of proximity sensors (4, 5, 6, 7) that are arranged in a rim portion (20) of the steering wheel (2) that can be held by the driver, and output detection values (Ch_1, Ch_2, Ch_3, Ch_4) that increase or decrease according to the distance between each arrangement position and a human body; and a holding determination device (8) that determines whether or not the rim portion (20) is held based on the detection values (Ch_1 to Ch_4) of the proximity sensors (4 to 7). The holding determination device (8) includes: a selection portion (81) that selects a target sensor from among the plurality of proximity sensors (4 to 7) based on the degree of change in the detection values of the plurality of proximity sensors (4 to 7); and a determination portion (82) that determines whether or not the rim portion (20) is held based on the detection value of the target sensor.

Description

Technical Field

[0001] This invention relates to a steering device. More specifically, it relates to a steering device that includes a steering wheel and a grip determination device for determining whether a driver is gripping the steering wheel. Background Technology

[0002] In recent years, to improve traffic safety, vehicles are being equipped with driver assistance devices such as lane keeping assist, lane departure mitigation, lane changing assist, and pedestrian following assist. In vehicles equipped with such driver assistance devices, for example, a grip detection device as shown in Patent Document 1 determines whether the driver is gripping the steering wheel. If the device determines that the driver is not gripping the steering wheel, it may urge the driver to grip the steering wheel or cancel the currently active driver assistance function.

[0003] In the grip determination device shown in Patent Document 1, the driver determines whether he or she is gripping the steering wheel based on the detection value of a proximity sensor installed on the rim of the steering wheel.

[0004] [Previous Technical Documents]

[0005] (Patent Documents)

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-69902 Summary of the Invention

[0007] [The problem the invention aims to solve]

[0008] However, in grip determination devices like those shown in Patent Document 1, where the determination of whether the driver is gripping the steering wheel is based on the detection value of a proximity sensor located on the wheel rim, if a part of the driver's body other than their hands is present near the steering wheel, it may sometimes be mistakenly determined that the driver is gripping the wheel rim even though they are not actually gripping it with their hands. More specifically, the larger the driver's build, the narrower the gap between the steering wheel and the driver's abdomen or knees, making such misjudgments more likely.

[0009] The purpose of this invention is to provide a steering device that can reasonably determine whether the driver is holding the steering wheel, regardless of the driver's physique.

[0010] [Technical means to solve the problem]

[0011] (1) The steering device of the present invention (e.g., the steering device 1 described later) is characterized in that it includes: a steering wheel (e.g., the steering wheel 2 described later) for receiving steering operations of the vehicle by the driver; a plurality of proximity sensors (e.g., the first proximity sensor 4, the second proximity sensor 5, the third proximity sensor 6 and the fourth proximity sensor 7 described later), a grip portion (e.g., the wheel rim portion 20 described later) disposed in the aforementioned steering wheel for the driver to hold, and output detection values ​​that increase or decrease according to the distance between each placement position and the human body; and a grip determination device (e.g., the grip determination device 8 described later) for determining whether or not the grip portion is held based on the detection values ​​of the aforementioned proximity sensors; the grip determination device includes: a selection unit (e.g., the selection unit 81 described later) for selecting an object sensor from the plurality of aforementioned proximity sensors based on the degree of change of the detection values ​​of the plurality of aforementioned proximity sensors; and a determination unit (e.g., the determination unit 82 described later) for determining whether or not the grip portion is held based on the detection values ​​of the aforementioned object sensor.

[0012] (2) Preferably, the selection unit selects the object sensor by comparing the magnitude of the changes in the detection values ​​of the plurality of proximity sensors.

[0013] (3) Preferably, the selection unit selects M (M is an integer of 1 or more and less than N) of the proximity sensors with the greatest variation from the N proximity sensors (N is an integer of 2 or more) in descending order as the object sensors.

[0014] (4) Preferably, the selection unit selects the object sensor by comparing the degree of change of the detection values ​​of the plurality of proximity sensors with a threshold, i.e., a selection threshold, set for the degree of change.

[0015] (5) Preferably, the selection unit selects the proximity sensor whose change is greater than the selection threshold from among the plurality of proximity sensors as the object sensor.

[0016] (6) Preferably, during the period when the aforementioned selection unit determines that the aforementioned gripping unit is not gripped, the aforementioned selection unit performs the selection process of selecting the aforementioned object sensor from the plurality of aforementioned proximity sensors at a predetermined period.

[0017] (7) Preferably, the determination unit determines whether the gripping part is being gripped at regular intervals. If the gripping part was not being gripped in the previous cycle, the determination is made based solely on the detection value of the proximity sensor selected as the object sensor among the plurality of proximity sensors. If the gripping part was being gripped in the previous cycle, the determination is made based on the detection values ​​of the plurality of proximity sensors.

[0018] (8) Preferably, the aforementioned determination unit determines that the aforementioned gripping unit is being gripped when the detection value of the aforementioned object sensor is above a threshold set for the detection value, i.e., a gripping threshold.

[0019] (9) Preferably, when the sum of the detection values ​​of the plurality of the aforementioned object sensors is above a threshold set for the detection value, i.e., a gripping threshold, the aforementioned determination unit determines that the aforementioned gripping unit is being gripped.

[0020] (The effect of the invention)

[0021] (1) In this invention, multiple proximity sensors are provided in the grip portion of the steering wheel that the driver can hold. Here, if the driver's build is larger than average, a part of the driver's body, such as the abdomen or knees, will be close to a specific part of the grip portion when seated in the driver's seat. Therefore, the detection value of the proximity sensor located near this specific part will consistently be higher than the standard and will not change significantly during driving. In contrast, the detection value of the proximity sensor located near the part of the driver's hand that grips the steering wheel changes significantly each time the driver grips it. Therefore, the selection unit of the grip determination device selects a target sensor from the multiple proximity sensors based on the degree of change in the detection values ​​of the multiple proximity sensors, and the determination unit of the grip determination device determines whether or not the driver is gripping the steering wheel based on the detection value of the selected target sensor. According to this invention, proximity sensors whose detection values ​​increase due to the driver's build can be excluded from the target sensors, so that regardless of the driver's build, a reasonable determination of whether or not the driver is gripping the steering wheel can be made, thereby improving traffic safety.

[0022] (2) In this invention, the selection unit selects the target sensor from the multiple proximity sensors by comparing the magnitude of the changes in the detection values ​​of the multiple proximity sensors. This allows the proximity sensor located near the part of the driver's hand that is gripping the device to be selected as the target sensor from the multiple proximity sensors.

[0023] (3) In this invention, the selection unit selects M proximity sensors as target sensors in descending order from among N proximity sensors, starting with the proximity sensors with the greatest degree of variation. This allows the proximity sensor located near the part of the driver's hand that is gripped to be selected as the target sensor from among multiple proximity sensors.

[0024] (4) In this invention, the selection unit selects a target sensor from multiple proximity sensors by comparing the degree of change of the detection values ​​of multiple proximity sensors with a threshold set for the degree of change, i.e., a selection threshold. Thus, the proximity sensor located near the part of the driver's hand that is held by the multiple proximity sensors can be selected as the target sensor.

[0025] (5) In this invention, the selection unit selects the proximity sensor whose change is greater than the selection threshold from among the multiple proximity sensors as the target sensor, thereby enabling the selection of the proximity sensor located near the part of the driver's hand that is held from among the multiple proximity sensors as the target sensor.

[0026] (6) In this invention, during the period when the determination unit determines that the grip is not being held, the selection unit performs a selection process of selecting an object sensor from multiple proximity sensors at a predetermined period, thereby enabling the appropriate object sensor to be selected each time the driver re-grips the grip or changes the grip position.

[0027] (7) In this invention, the determination unit determines whether the gripping part is being held at predetermined intervals. Furthermore, if it was determined in the previous interval that the gripping part was not being held, the determination is based solely on the detection value of the sensor selected as the object sensor by the selection unit. This allows for accurate determination of whether the driver is holding the gripping part. Additionally, if the determination unit determined in the previous interval that the gripping part was being held, it determines whether the gripping part is being held based on the detection values ​​of multiple proximity sensors. This allows for reasonable determination of whether the gripping part is being held, even if the driver is holding the gripping part and sliding the gripping area.

[0028] (8) In this invention, if the detection value of the object sensor is above a threshold set for that detection value, i.e., a grip threshold, the determination unit determines that the gripping part is being gripped, thereby enabling accurate determination that the driver is gripping the object sensor near its location.

[0029] (9) In this invention, the determination unit determines that the gripping part is being gripped when the sum of the detection values ​​of multiple object sensors is above a threshold set for that detection value, namely a gripping threshold. Thus, for example, even when the driver grips the part across the placement of multiple proximity sensors, it is still possible to determine with good accuracy whether or not a grip is being held. Attached Figure Description

[0030] Figure 1 This is a diagram illustrating the structure of a steering device according to one embodiment of the present invention.

[0031] Figure 2 This is a diagram illustrating the circuit structure of the first detection circuit.

[0032] Figure 3 This is a flowchart illustrating the process by which a driver determines whether they are gripping the wheel rim based on the detection values ​​of multiple proximity sensors in a grip determination device.

[0033] Figure 4 It is a flowchart illustrating the specific process of the first grip determination.

[0034] Figure 5 This is a flowchart illustrating the specific process of the second grip determination and processing. Detailed Implementation

[0035] Hereinafter, a steering device according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0036] Figure 1 This is a diagram illustrating the structure of the steering device 1 according to this embodiment. The steering device 1 is mounted on a vehicle not shown. The steering device 1 includes: a steering wheel 2, which receives steering operations from the driver or auxiliary operations from the vehicle's auxiliary machinery; a steering shaft 3, which pivots the steering wheel 2; a plurality of (four in this embodiment) proximity sensors 4, 5, 6, 7, which are disposed on the steering wheel 2; and a grip determination device 8, which determines whether the driver is gripping the steering wheel 2 based on the detection results of these proximity sensors 4 to 7.

[0037] The steering wheel 2 includes: a ring-shaped rim portion 20 that serves as a grip portion for the driver; a hub portion 23 disposed on the inner side of the rim portion 20; and three spoke portions 25L, 25R, 25D that extend radially from the hub portion 23 and are connected to the inner circumference portion 21 of the rim portion 20.

[0038] The hub portion 23 is disc-shaped and, for example, is located at the center of the rim portion 20 as viewed from the driver, forming the center of the steering wheel 2. On the rear side of the hub portion 23 as viewed from the driver, a steering shaft 3 is connected to pivotally support the steering wheel 2. The steering shaft 3 is a shaft-shaped connecting component that connects the frame, i.e., the core, of the hub portion 23 to the steering mechanism, which constitutes part of the vehicle body (not shown). Therefore, the steering torque generated by the driver rotating the steering wheel 2 is transmitted to the steering mechanism (not shown) via this steering shaft 3.

[0039] 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 horizontally, connecting the left-side portion of the hub portion 23 as viewed from the driver's perspective to the left-side portion of the inner rim portion 21 as viewed from the driver's perspective. The right spoke portion 25R extends horizontally and parallel to the left spoke portion 25L, connecting the right-side portion of the hub portion 23 as viewed from the driver's perspective to the right-side portion of the inner rim portion 21 as viewed from the driver's perspective. The lower spoke portion 25D extends vertically and orthogonally to the spoke portions 25L and 25R, connecting the lower portion of the hub portion 23 as viewed from the driver's perspective to the lower portion of the inner rim portion 21 as viewed from the driver's perspective.

[0040] As described above, the wheel rim 20 is circular from the driver's perspective, allowing the driver to grip it around its entire circumference. Furthermore, electrode portions 40, 50, 60, and 70 of a plurality of proximity sensors 4, 5, 6, and 7 (described later) are arranged throughout the entire circumference of the wheel rim 20.

[0041] A left auxiliary machine operation control unit 27L and a right auxiliary machine operation control unit 27R are respectively provided on the left wheel spoke portion 25L and the right wheel spoke portion 25R. These units accept driver-operated auxiliary machine operations for operating vehicle auxiliary machines (e.g., audio devices or car navigation systems). The driver can operate the vehicle auxiliary machines by using their fingers to operate multiple switches provided in these auxiliary machine operation control units 27L and 27R.

[0042] Furthermore, the following description may also use a clockwise angle [°] centered on the steering shaft 3 and based on the upper end 20C of the wheel rim portion 20 as viewed from the driver to indicate the position of the wheel rim portion 20, the inner rim portion 21, the hub portion 23, and the steering shaft 3, or the orientation of each spoke portion 25L, 25R, 25D, which is approximately circular as viewed from the driver. Specifically, the right spoke portion 25R extends along a 90° direction, connecting the hub portion 23 and the 90° portion of the inner rim portion 21. The lower spoke portion 25D extends along a 180° direction, connecting the hub portion 23 and the 180° portion of the inner rim portion 21. Additionally, the left spoke portion 25L extends along a 270° direction, connecting the hub portion 23 and the 270° portion of the inner rim portion 21.

[0043] The first proximity sensor 4 includes a first electrode portion 40 disposed on the rim portion 20 and a first detection circuit 42 electrically connected to the first electrode portion 40. The first electrode portion 40 is an arc-shaped portion extending along the rim portion 20 and is conductive. The first electrode portion 40 is disposed inside the rim portion 20. The first electrode portion 40 is positioned within the rim portion 20 at approximately 90°, between 45° and 135° (i.e., the range where the driver can primarily grip with their right hand). Furthermore, the position of the first electrode portion 40 within the rim portion 20 will be referred to below as the right rim portion 20R. The first detection circuit 42 is connected to the first electrode portion 40 via a wiring 41. The first detection circuit 42 detects the electrostatic capacitance between the first electrode portion 40 and ground, as a value that increases or decreases depending on the distance between the position of the first electrode portion 40 and the human body. The closer the position of the first electrode portion 40 is to the human body, the greater the electrostatic capacitance between the first electrode portion 40 and ground. The detection value Ch_1 of the electrostatic capacitance by the first detection circuit 42 is sent to the grip determination device 8.

[0044] Figure 2 This is a diagram illustrating the circuit structure of the first detection circuit 42.

[0045] The first detection circuit 42 includes a pulse power supply 43, an amplifier 44, a first switch 45, a second switch 46, a charging capacitor 47, and an electrostatic capacitance measuring unit 48. Furthermore, in Figure 2 In the diagram, the electrostatic capacitance between the first electrode part 40 and the ground (e.g., the vehicle body) is divided into the following capacitances: the electrostatic capacitance Ch formed by the human body H, including the driver's hand operating the steering wheel 2, and the stray capacitance Ce formed by stray capacitors E, such as wiring or parts other than the human body H.

[0046] like Figure 2 As shown, the pulse power supply 43 is connected in series with the amplifier 44. The second switch 46 is connected in parallel with the charging capacitor 47. The series circuit consisting of the pulse power supply 43 and the amplifier 44 and the parallel circuit consisting of the second switch 46 and the charging capacitor 47 are connected via the first switch 45. The output terminal of the amplifier 44 and the first switch 45 are connected to the first electrode section 40 via wiring 41. Therefore, the pulse power supply 43 is connected to the first electrode section 40 via the amplifier 44 and wiring 41. In addition, the second switch 46 and the charging capacitor 47 are connected to the first electrode section 40 via the first switch 45 and wiring 41, respectively.

[0047] According to the instruction from the grip determination device 8, the pulse power supply 43 supplies a pulse voltage Vs of a specified frequency and a specified voltage to the amplifier 44. The amplifier 44 amplifies the pulse voltage Vs supplied from the pulse power supply 43 and applies it to the first electrode section 40.

[0048] The second switch 46 is a switching element that is turned on / off by a drive circuit (not shown). The drive circuit of the second switch 46, for example, turns the second switch 46 off before the voltage VCref of the charging capacitor 47 reaches a predetermined threshold Vthr, and turns the second switch 46 on after the voltage VCref reaches the threshold Vthr to discharge the charge stored in the charging capacitor 47.

[0049] The first switch 45 is a switching element that is turned on / off by a drive circuit (not shown). The drive circuit of the first switch 45 turns off the first switch 45 according to the rise of the pulse voltage Vs of the pulse power supply 43. As a result, a pulse voltage supplied from the pulse power supply 43 and the amplifier 44 is applied to the first electrode portion 40, and the charge... Figure 2 It moves along the path indicated by the middle arrow 2a, charging the human body H and the stray capacitor E.

[0050] Furthermore, the drive circuit of the first switch 45 turns on the first switch 45 according to the decrease in the pulse voltage Vs of the pulse power supply 43. This connects the human body H and the stray capacitor E to the charging capacitor 47, and the charge flows through... Figure 2 The path indicated by the middle arrow 2b moves from the human body H and stray capacitor E to the charging capacitor 47, charging the charging capacitor 47. As a result, the voltage VCref of the charging capacitor 47 increases.

[0051] Therefore, when a pulse voltage is applied to the first electrode portion 40 via the pulse power supply 43 and amplifier 44, the charging and discharging of the human body H and stray capacitor E alternate repeatedly, and the voltage VCref of the charging capacitor 47 gradually increases. At this time, the time it takes for the voltage VCref of the charging capacitor 47 to reach the threshold Vthr (or the number of pulses of the pulse power supply 43) varies depending on the electrostatic capacitance Ch formed by the human body H, i.e., the distance between the first electrode portion 40 and the driver's body. That is, when a part of the driver's body is in contact with or close to the first electrode portion 40 in the wheel rim portion 20, and the electrostatic capacitance Ch is high, the time it takes for the voltage VCref of the charging capacitor 47 to reach the threshold Vthr is shorter; when a part of the driver's body is far away from the first electrode portion 40, and the electrostatic capacitance Ch is low, the time it takes for the voltage VCref of the charging capacitor 47 to reach the threshold Vthr is longer.

[0052] The electrostatic capacitance measuring unit 48 measures the time or number of pulses until the voltage VCref of the charging capacitor 47 reaches the threshold Vthr, and indirectly measures the electrostatic capacitance Ch formed by the human body H present near the first electrode 40 based on the measurement result. The electrostatic capacitance measuring unit 48 sends the detection value Ch_1 of the electrostatic capacitance Ch obtained by the above process to the grip determination device 8.

[0053] return Figure 2 The second proximity sensor 5 includes a second electrode portion 50 disposed on the rim portion 20 and a second detection circuit 52 electrically connected to the second electrode portion 50. The second electrode portion 50 is an arc-shaped portion extending along the rim portion 20 and is conductive. The second electrode portion 50 is disposed inside the rim portion 20. The second electrode portion 50 is positioned within the rim portion 20 in an approximately 90° range between 225° and 315° (i.e., the range where the driver can primarily grip with their left hand). Furthermore, the position of the second electrode portion 50 within the rim portion 20 will also be referred to below as the left rim portion 20L. The second detection circuit 52 is connected to the second electrode portion 50 via a wiring 51. The second detection circuit 52 detects the electrostatic capacitance between the second electrode portion 50 and ground, as a value that increases or decreases depending on the distance between the position of the second electrode portion 50 and the human body. The closer the position of the second electrode portion 50 is to the human body, the greater the electrostatic capacitance between the second electrode portion 50 and ground. The second detection circuit 52 sends the electrostatic capacitance value Ch_2 to the grip determination device 8. Furthermore, the circuit structure of the second detection circuit 52 is similar to... Figure 2 The first detection circuit 42 shown is almost identical, so detailed descriptions are omitted.

[0054] The third proximity sensor 6 includes a third electrode portion 60 disposed on the wheel rim portion 20 and a third detection circuit 62 electrically connected to the third electrode portion 60. The third electrode portion 60 is an arc-shaped portion extending along the wheel rim portion 20 and is conductive. The third electrode portion 60 is disposed inside the wheel rim portion 20. The third electrode portion 60 is positioned within the wheel rim portion 20 in an approximately 90° range between 315° and 405° (45°) (i.e., the range within which the driver can hold it with their right or left hand). Furthermore, the position of the third electrode portion 60 within the wheel rim portion 20 will also be referred to below as the upper part 20U of the wheel rim portion. The third detection circuit 62 is connected to the third electrode portion 60 via a wiring 61. The third detection circuit 62 detects the electrostatic capacitance between the third electrode portion 60 and ground, as a value that increases or decreases depending on the distance between the position of the third electrode portion 60 and the human body. The closer the position of the third electrode portion 60 is to the human body, the greater the electrostatic capacitance between the third electrode portion 60 and ground. The third detection circuit 62 sends the electrostatic capacitance value Ch_3 to the grip determination device 8. Furthermore, the circuit structure of the third detection circuit 62 is similar to... Figure 2 The first detection circuit 42 shown is almost identical, so detailed descriptions are omitted.

[0055] The fourth proximity sensor 7 includes a fourth electrode portion 70 disposed on the wheel rim portion 20 and a fourth detection circuit 72 electrically connected to the fourth electrode portion 70. The fourth electrode portion 70 is an arc-shaped portion extending along the wheel rim portion 20 and is conductive. The fourth electrode portion 70 is disposed inside the wheel rim portion 20. The fourth electrode portion 70 is positioned within approximately 90° of the wheel rim portion 20, between 135° and 225° (i.e., within the range where the driver can grip with their right or left hand and within the range of the wheel rim portion 20 closest to the driver's knee). Furthermore, the position of the fourth electrode portion 70 within the wheel rim portion 20 will also be referred to below as the lower part 20D of the wheel rim portion. The fourth detection circuit 72 is connected to the fourth electrode portion 70 via a wiring 71. The fourth detection circuit 72 detects the electrostatic capacitance between the fourth electrode portion 70 and ground, as a value that increases or decreases according to the distance between the position of the fourth electrode portion 70 and the human body. The closer the position of the fourth electrode portion 70 is to the human body, the greater the electrostatic capacitance between the fourth electrode portion 70 and ground. The fourth detection circuit 72 sends the electrostatic capacitance value Ch_4 to the grip determination device 8. Furthermore, the circuit structure of the fourth detection circuit 72 is similar to... Figure 2 The first detection circuit 42 shown is almost identical, so detailed descriptions are omitted.

[0056] The grip determination device 8 determines whether the driver is gripping the wheel rim 20, i.e. whether the driver is gripping the wheel rim 20, based on the detection values ​​Ch_1, Ch_2, Ch_3, Ch_4 of the four proximity sensors 4 to 7 respectively arranged at different positions on the wheel rim 20 as described above.

[0057] The grip determination device 8 includes: a selection unit 81, which selects an object sensor from the four proximity sensors 4, 5, 6, 7 based on the degree of change of the detection values ​​Ch_1, Ch_2, Ch_3, Ch_4 of the four proximity sensors 4, 5, 6, 7 within a specified time period; and a determination unit 82, which determines whether the driver has gripped the wheel rim 20 based on the detection value of the object sensor selected by the selection unit 81.

[0058] Figure 3 This is a flowchart illustrating the process in the grip determination device 8 that determines whether the driver is gripping the wheel rim based on detection values ​​Ch_1 to Ch_4. (About...) Figure 3 The process shown is repeated in the grip determination device 8 under a predetermined control cycle based on the situation where the vehicle is started by the driver operating the start switch (not shown).

[0059] First, in step ST1, the selection unit 81 and the determination unit 82 acquire the detection values ​​Ch_1 to Ch_4 of each proximity sensor 4 to 7, and then proceed to step ST2.

[0060] Next, in step ST2, the determination unit 82 determines whether the value of the grip mark Fg is "1". The grip mark Fg is a mark indicating that the driver is gripping the wheel rim 20 with his hand. It is set to the value "0" in step ST17 or ST24 described later, and to the value "1" in step ST16 or ST23 described later.

[0061] If the determination unit 82 determines that the result of step ST2 is NO, that is, if it determined in the previous control cycle that the rim portion 20 was not gripped, it proceeds to step ST3. In step ST3, the determination unit 82 performs the following steps. Figure 4 The first grip detection process is shown, and then it ends. Figure 3 The processing is as shown. Furthermore, if the determination result of the determination unit 82 in step ST2 is YES, that is, if it was determined in the previous control cycle that the rim portion 20 was being held, then the process proceeds to step ST4. In step ST4, the determination unit 82 performs the process described later. Figure 5 The second gripping determination process is shown, and then it ends. Figure 3 The processing shown.

[0062] Figure 4 It is a flowchart illustrating the specific process of the first grip determination.

[0063] First, in step ST11, the selection unit 81 calculates the degree of change ΔCh_1, ΔCh_2, ΔCh_3, ΔCh_4 of the detection values ​​Ch_1, Ch_2, Ch_3, Ch_4 of each proximity sensor 4 to 7 within a specified time period, and proceeds to step ST12. More specifically, the selection unit 81 subtracts the detection values ​​Ch_1 to Ch_4 of each proximity sensor 4 to 7 acquired in the current control cycle from the detection values ​​Ch_1 to Ch_4 of each proximity sensor 4 to 7 acquired in the control cycle n cycles (n being an integer of 1 or more), thereby calculating the degree of change ΔCh_1 to ΔCh_4 of each proximity sensor 4 to 7. Therefore, the degree of change ΔCh_1 to ΔCh_4 calculated in step ST11 corresponds to the amount of approach of a part of the driver's body relative to the placement position of each electrode part 40 to 70 within a specified time period, i.e., the approach speed.

[0064] In step ST12, the selection unit 81 selects a target sensor from the plurality of proximity sensors 4 to 7 based on the degree of change ΔCh_1 to ΔCh_4 of each proximity sensor 4 to 7 calculated in step ST11, and then proceeds to step ST13. More specifically, the selection unit 81 selects the proximity sensor with the largest degree of change in the detected value from the plurality of proximity sensors 4 to 7 as the target sensor. Here, two examples of the specific process by which the selection unit 81 selects a target sensor from the plurality of proximity sensors will be described.

[0065] In the first example, the selection unit 81 selects the target sensor by comparing the magnitudes of the changes in the detection values ​​ΔCh_1 to ΔCh_4 of the plurality of proximity sensors 4 to 7. More specifically, the selection unit 81 selects M (M is an integer of 1 or more and less than N) as target sensors from among the N (N is an integer of 2 or more, and 4 in this embodiment) proximity sensors 4 to 7, starting with the proximity sensor with the largest change in ΔCh_1 to ΔCh_4. Therefore, in the first example, among the plurality of proximity sensors 4 to 7, M are selected as target sensors sequentially, starting with the proximity sensor with the largest approach speed of a part of the driver's body relative to the arrangement position of each electrode part 40 to 70.

[0066] In the second example, the selection unit 81 selects a target sensor by comparing the degree of change ΔCh_1 to ΔCh_4 of the detection values ​​of the plurality of proximity sensors 4 to 7 with a pre-defined selection threshold. More specifically, the selection unit 81 selects the proximity sensors among the plurality of proximity sensors 4 to 7 whose degree of change ΔCh_1 to ΔCh_4 is greater than the selection threshold as target sensors. This selection threshold is a threshold set for the degree of change of the detection values ​​of the proximity sensors 4 to 7, which corresponds to the approach speed of a part of the driver's body relative to the arrangement position of each electrode part 40 to 70 as described above. Therefore, in the second example, among the plurality of proximity sensors 4 to 7, the proximity sensor whose approach speed of a part of the driver's body relative to the arrangement position of each electrode part 40 to 70 is faster than the speed corresponding to the selection threshold is selected as the target sensor.

[0067] In step ST13, the determination unit 82 determines whether at least one of the plurality of proximity sensors 4 to 7 was selected as the target sensor in step ST12. If the determination result of step ST13 is YES, the determination unit 82 proceeds to step ST14; if it is NO, it proceeds to step ST17.

[0068] In step ST14, the determination unit 82 calculates the total value of the detection values ​​of the proximity sensors selected as the object sensors among the plurality of proximity sensors, and proceeds to step ST15. In step ST15, the determination unit 82 determines whether the total value of the detection values ​​of the object sensors calculated in step ST14 (i.e., the detection value of the object sensor if there is only one object sensor) is greater than or equal to a predetermined first grip threshold. This first grip threshold is a threshold set for the detection values ​​of proximity sensors 4 to 7, i.e., the electrostatic capacitance, which corresponds to the distance of a part of the driver's body relative to the arrangement position of each electrode part 40 to 70.

[0069] If the determination result of step ST15 is YES, the determination unit 82 proceeds to step ST16. In step ST16, the determination unit 82 determines that the wheel rim 20 is being held by the driver and ends the process. Figure 4 The processing. More specifically, in step ST16, the determination unit 82 sets the value of the gripping flag Fg to "1" and ends the process. Figure 4 The processing.

[0070] Furthermore, if the determination unit 82 determines that the result of step ST15 is NO, or if the result of step ST13 is NO, it proceeds to step ST17. In step ST17, the determination unit 82 determines that the wheel rim 20 is not being held by the driver and ends the process. Figure 4 The processing. More specifically, in step ST17, the determination unit 82 maintains the value of the holding flag Fg at "0" and ends the process. Figure 4 The processing.

[0071] As described above, during the period when the determination unit 82 determines that the rim portion 20 is not gripped (i.e., the value of the gripping mark Fg is set to "0"), the selection unit 81 repeatedly performs the selection process of choosing the target sensor from multiple proximity sensors 4 to 7 within a predetermined control cycle. Figure 4 Steps ST11 to ST12). In addition, if the determination unit 82 determines in the previous control cycle that the rim 20 is not gripped (that is, when the gripping flag Fg is set to "0"), it determines whether the rim 20 is gripped or not based solely on the detection value of the proximity sensor selected as the object sensor by the above selection process among the multiple proximity sensors 4 to 7.

[0072] Figure 5 This is a flowchart illustrating the specific process of the second grip determination and processing.

[0073] First, in step ST21, the determination unit 82 calculates the total value of the detection values ​​Ch_1 to Ch_4 of the multiple proximity sensors 4 to 7, more specifically, all proximity sensors 4 to 7 provided on the wheel rim portion 20, and proceeds to step ST22. In step ST22, the determination unit 82 determines whether the total value calculated in step ST21 is above or above a second grip threshold. This second grip threshold, like the first grip threshold described above, is a threshold established for the detection values ​​of the proximity sensors 4 to 7, i.e., the electrostatic capacitance, which corresponds to the distance of a part of the driver's body relative to the placement position of each electrode portion 40 to 70.

[0074] If the determination result of step ST22 is YES, the determination unit 82 proceeds to step ST23. In step ST23, the determination unit 82 determines that the wheel rim 20 is being held by the driver and ends the process. Figure 5 The processing. More specifically, in step ST23, the determination unit 82 maintains the value of the holding flag Fg at "1" and ends the process. Figure 5 The processing.

[0075] Furthermore, if the determination result of step ST22 is NO, the determination unit 82 proceeds to step ST24. In step ST24, the determination unit 82 determines that the wheel rim 20 is not being held by the driver and ends the process. Figure 5 The processing. More specifically, in step ST24, the determination unit 82 sets the value of the gripping flag Fg to "0" and ends the process. Figure 5 The processing.

[0076] As described above, if the selection unit 81 determines in the previous control cycle that the rim portion 20 is being held (i.e., the value of the holding flag Fg is set to "1"), it determines whether the rim portion 20 is being held based on the detection values ​​of the multiple proximity sensors 4 to 7, or more specifically, all the proximity sensors 4 to 7 provided on the rim portion 20.

[0077] The steering device 1 according to this embodiment has the following effects.

[0078] (1) In the steering device 1, multiple proximity sensors 4 to 7 are provided on the rim portion 20 within the steering wheel 2 where the driver can grip. Here, if the driver's build is larger than average, parts of the driver's body, such as the abdomen or knees, will be close to the lower part 20D of the rim portion when seated in the driver's seat. Therefore, the detection value Ch_4 of the fourth proximity sensor 7 located near the lower part 20D of the rim portion will be consistently higher than the standard and will not change significantly during driving. In contrast, the detection value of the proximity sensor located near the part of the driver's hand gripping the wheel changes significantly each time the driver grips it. Therefore, the selection unit 81 of the grip determination device 8 selects a target sensor from the multiple proximity sensors 4 to 7 based on the degree of change ΔCh_1 to ΔCh_4 of the detection values ​​Ch_1 to Ch_4 of the multiple proximity sensors 4 to 7, and the determination unit 82 of the grip determination device 8 determines whether gripping has occurred based on the detection value of the selected target sensor. According to the steering device 1, proximity sensors whose detection values ​​increase due to the driver's size can be excluded from the object sensors from among multiple proximity sensors 4 to 7. Therefore, regardless of the driver's size, it is possible to reasonably determine whether the driver is holding the wheel rim 20, thereby improving traffic safety.

[0079] (2) The selection unit 81 selects the target sensor from the plurality of proximity sensors 4 to 7 by comparing the magnitudes of the changes in the detection values ​​Ch_1 to Ch_4 of the plurality of proximity sensors 4 to 7, thereby enabling the proximity sensor located near the part of the driver's hand to be held as the target sensor from the plurality of proximity sensors 4 to 7.

[0080] (3) The selection unit 81 selects M proximity sensors as target sensors from among the N proximity sensors 4 to 7, starting with the proximity sensors with the greatest variation, in descending order. In this way, the proximity sensor located near the part of the driver's hand that is held can be selected as the target sensor from among the multiple proximity sensors 4 to 7.

[0081] (4) The selection unit 81 selects a target sensor from the plurality of proximity sensors 4 to 7 by comparing the degree of change ΔCh_1 to ΔCh_4 of the detection values ​​Ch_1 to Ch_4 of the plurality of proximity sensors 4 to 7 with a threshold set for the degree of change, namely the selection threshold. Thus, the proximity sensor located near the part of the driver's hand that is held by the plurality of proximity sensors 4 to 7 can be selected as the target sensor.

[0082] (5) The selection unit 81 selects the proximity sensor among the plurality of proximity sensors 4 to 7 whose change degree ΔCh_1 to ΔCh_4 is greater than the selection threshold as the target sensor, thereby enabling the proximity sensor located near the part of the driver's hand to be held as the target sensor from the plurality of proximity sensors 4 to 7.

[0083] (6) During the period when the determination unit 82 determines that the wheel rim is not gripped, the selection unit 81 performs a selection process from multiple proximity sensors 4 to 7 at a predetermined control cycle, thereby enabling the appropriate object sensor to be selected each time the driver re-grips the wheel rim 20 or changes the grip position.

[0084] (7) The determination unit 82 determines whether the rim portion 20 is being gripped at predetermined control cycles. If it was determined that the rim portion 20 was not being gripped in the previous control cycle, the determination is based solely on the detection values ​​of the sensors selected as object sensors by the selection unit 81. This allows for accurate determination of whether the driver is gripping the rim portion 20. Furthermore, if the determination unit 82 determined that the rim portion 20 was being gripped in the previous control cycle, the determination is based on the detection values ​​of all proximity sensors 4 to 7 installed on the rim portion 20. This allows for reasonable determination of whether the driver is gripping the rim portion 20, for example, even if the driver is gripping the rim portion 20 and sliding the gripping area.

[0085] (8) When the detection value of the object sensor is above the threshold value set for the detection value, i.e., the first grip threshold, the determination unit 82 determines that the wheel rim 20 is being gripped, thereby accurately determining that the driver is gripping the object sensor near the location of the object sensor.

[0086] (9) If the sum of the detection values ​​of the multiple object sensors is greater than or equal to a threshold set for that detection value, namely a first grip threshold or a second grip threshold, the determination unit 82 determines that the wheel rim portion 20 is being gripped. Thus, for example, even if the driver grips the wheel rim portion across the placement area of ​​the multiple proximity sensors 4 to 7, it is still possible to determine with good accuracy whether or not the wheel rim portion is being gripped.

[0087] The above description pertains to one embodiment of the present invention, but the invention is not limited thereto. Appropriate modifications to the structural details are possible within the scope of the spirit of the invention.

[0088] For example, in the above embodiment, four proximity sensors 4 to 7 are arranged on the rim portion 20, but the number of proximity sensors arranged on the rim portion 20 is not limited to this. The present invention can be applied as long as two or more proximity sensors are arranged on the rim portion 20.

[0089] Figure Labels

[0090] 1: Steering mechanism

[0091] 2: Steering wheel

[0092] 20: Wheel rim (grip)

[0093] 3: Steering shaft

[0094] 4: First proximity sensor (proximity sensor)

[0095] 40: First electrode section

[0096] 42: First detection circuit

[0097] 5: Second proximity sensor (proximity sensor)

[0098] 50: Second electrode section

[0099] 52: Second detection circuit

[0100] 6: Third proximity sensor (proximity sensor)

[0101] 60: Third electrode section

[0102] 62: Third detection circuit

[0103] 7: Fourth proximity sensor (proximity sensor)

[0104] 70: Fourth Electrode Section

[0105] 72: Fourth detection circuit

[0106] 8: Grip detection device

[0107] 81: Selection Department

[0108] 82: Judgment Department

Claims

1. A steering device, characterized in that, include: The steering wheel receives the driver's steering inputs. Multiple proximity sensors are configured in the aforementioned steering wheel within the driver's grip area, and output detection values ​​that increase or decrease based on the distance between each configuration position and the human body. and, The grip determination device determines whether or not the gripping part is being gripped based on the detection value of the aforementioned proximity sensor; The aforementioned grip determination device includes: The selection unit selects an object sensor from the plurality of proximity sensors based on the degree of change in the detection values ​​of the plurality of proximity sensors; and, The determination unit determines whether or not the gripping part is being held based on the detection values ​​from the aforementioned object sensor. The selection unit selects the object sensor by comparing the magnitude of the changes in the detection values ​​of the multiple proximity sensors.

2. The steering device according to claim 1, wherein, The selection unit starts with the proximity sensors that vary the most from among the N (N is an integer of 2 or more) proximity sensors, and selects M (M is an integer of 1 or more and less than N) as the target sensors in descending order.

3. The steering device according to claim 1 or 2, wherein, During the period when the aforementioned selection unit determines that the aforementioned gripping unit is not being gripped, the aforementioned selection unit performs selection processing from multiple aforementioned proximity sensors to select the aforementioned object sensor at a predetermined cycle.

4. The steering device according to claim 1 or 2, wherein, The aforementioned determination unit determines whether or not there is a grip on the aforementioned gripping part at predetermined intervals, and, If it was determined in the previous cycle that the aforementioned gripping part was not gripped, the determination of whether or not the gripping part was gripped is based solely on the detection value of the aforementioned proximity sensor selected as the object sensor among the multiple aforementioned proximity sensors. If it was determined in the previous cycle that the aforementioned gripping part was being gripped, the determination of whether or not the gripping part was being gripped is based on the detection values ​​of multiple aforementioned proximity sensors.

5. The steering device according to claim 1, wherein, If the detection value of the aforementioned object sensor is above a threshold set for that detection value, namely the gripping threshold, the aforementioned determination unit determines that the aforementioned gripping part is being gripped.

6. The steering device according to claim 1, wherein, If the sum of the detection values ​​of the aforementioned object sensors is above a threshold set for the detection values, i.e., a gripping threshold, the aforementioned determination unit determines that the aforementioned gripping part is being gripped.

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