JP6406761B2 - Holding state detection device - Google Patents

Description

  The present invention relates to a gripping state detection device that detects whether or not a driver of a vehicle is gripping a steering wheel.

  A torque sensor and a touch sensor are mounted on the vehicle. For example, Patent Document 1 discloses a device that cancels automatic steering when a steering torque detected by a torque sensor is equal to or greater than a threshold value during automatic steering in a vehicle. Patent Document 2 discloses a device that detects a position where a driver is in contact with a steering wheel. The device described in Patent Document 2 is provided with a plurality of touch sensors (pressure sensor, capacitance sensor, electrode pair, etc.) along the rim portion.

Japanese Patent Laying-Open No. 2005-066732 Special table 2003-535757 gazette

  The device described in Patent Document 2 can detect the gripping state (gripping or non-gripping) of the steering wheel when the driver grips the rim portion. However, with this device, when the driver grips the spoke portion, the gripping state of the steering wheel cannot be detected.

  It is also possible to use a torque sensor instead of the touch sensor and detect the gripping state of the steering wheel depending on, for example, the presence or absence of a predetermined or higher steering torque. However, the torque sensor detects not only the steering torque input from the steering wheel side but also the steering torque input from the road surface side. For this reason, if the gripping state of the steering wheel is detected using only the torque sensor, erroneous determination increases.

  The present invention has been made in consideration of such problems, and an object of the present invention is to provide a gripping state detection device capable of detecting the gripping state of the steering wheel with high accuracy regardless of the gripping position of the driver.

  The grip state detection device according to the present invention includes a touch sensor that detects a contact state of a driver with respect to a steering wheel, a torque sensor that detects steering torque, and the driver based on detection results of the touch sensor and the torque sensor. And a gripping state detector for detecting the gripping state of the steering wheel.

  According to the above configuration, when the driver grips the touch sensor formation site, at least the touch sensor can detect the driver's contact with the steering wheel. In addition, when the driver grips a part other than the touch sensor formation portion, the driver's steering input can be detected by the torque sensor. Therefore, it is possible to detect the gripping state of the steering wheel with high accuracy regardless of the gripping position of the driver.

  In the present invention, the gripping state detection unit detects the driver's intention to drive based on the gripping state of the steering wheel by the driver, and further, the gripping state detection unit causes the driver to have a driving intention. You may provide the alarm control part which outputs an alarm signal when it detects that it does not, and the alarm machine which issues an alarm when the said alarm signal is received.

  According to the above configuration, the driver's intention to drive can be determined from the gripping state of the steering wheel, and when the driver does not have the driving intention, the driver can be alerted to drive, in this case, the steering wheel can be gripped.

  In the present invention, the gripping state detection unit obtains a torque difference between the steering torque detected by the torque sensor and a predetermined reference torque, and the steering wheel grips when the torque difference is equal to or larger than the predetermined torque difference. May be detected.

  According to the above configuration, the presence or absence of gripping can be appropriately determined by comparing the torque difference between the steering torque and the reference torque with the predetermined torque difference.

  In the present invention, a vehicle speed sensor for detecting a vehicle speed is provided, and the gripping state detection unit detects the steering torque detected by the torque sensor and a predetermined value when the vehicle speed detected by the vehicle speed sensor is less than a predetermined vehicle speed. A difference in torque from the reference torque is obtained, and when the torque difference is greater than or equal to a first torque difference, it is detected that the steering wheel is gripped, and the vehicle speed detected by the vehicle speed sensor is greater than or equal to a predetermined vehicle speed. In some cases, the torque difference between the steering torque detected by the torque sensor and the reference torque is obtained, and when the torque difference is greater than or equal to a second torque difference greater than the first torque difference, the steering wheel It may be detected that is gripped.

  According to the above configuration, since the value to be compared with the torque difference between the steering torque and the reference torque is changed according to the vehicle speed, even when the vehicle is traveling at a low speed where the torque difference between the steering torque and the reference torque is small, Appropriate presence or absence of gripping can be determined.

  In the present invention, a vehicle speed sensor that detects a vehicle speed is provided, and the grip state detection unit detects a grip state based on a detection result of the touch sensor when the vehicle speed detected by the vehicle speed sensor is less than a predetermined vehicle speed. While detecting the gripping state based on the detection result of the torque sensor, and when the vehicle speed detected by the vehicle speed sensor is equal to or higher than a predetermined vehicle speed, based on the detection result of the touch sensor and the torque sensor The gripping state may be detected.

  When there is steering intervention due to automatic driving or the like, almost no operation by the driver is required when the vehicle speed is low. As a result, a difference in torque between the steering torque generated by the vehicle and the steering torque generated by the driver operating the steering wheel becomes difficult, so the reliability of grip detection by a torque detection device such as a torque sensor decreases. . According to the above configuration, since the grip detection by the torque detection device is stopped at a low speed when the reliability of the grip detection by the torque detection device such as the torque sensor is low, it is possible to appropriately determine whether or not the grip is held.

  In the present invention, the touch sensor may be provided on a rim portion of the steering wheel.

  According to the said structure, the holding state with respect to the rim | limb part with high possibility of being hold | gripped by a driver | operator can be detected with a touch sensor.

  In the present invention, the touch sensor may be formed of a conductive paint applied to the steering wheel.

  According to the above configuration, the touch sensor can be easily formed.

  ADVANTAGE OF THE INVENTION According to this invention, when a driver | operator grips a touch sensor formation site | part, a driver | operator's contact with respect to a steering wheel can be detected with a touch sensor at least. In addition, when the driver grips a part other than the touch sensor formation portion, the driver's steering input can be detected by the torque sensor. Therefore, it is possible to detect the gripping state of the steering wheel with high accuracy regardless of the gripping position of the driver.

FIG. 1 is a configuration diagram of a vehicle equipped with a gripping state detection device according to the present invention. FIG. 2 is a flowchart of the alarm process according to the first embodiment. 3A and 3B are diagrams showing gripping / driving intention determination information. 4A and 4B are correlation diagrams between the steering operation frequency and the steering torque. FIG. 5 is a flowchart of the hands-on determination process. FIG. 6 is a flowchart of the first torque determination process. FIG. 7 is a flowchart of the alarm process according to the second embodiment. FIG. 8 is a flowchart of the second torque determination process.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a gripping state detection device according to the present invention will be described in detail with reference to the accompanying drawings by giving preferred embodiments.

[1 First Embodiment]
[1.1 Vehicle 10]
The vehicle 10 will be described with reference to FIG. The vehicle 10 is an internal combustion engine vehicle in which an internal combustion engine is mounted as a driving source for traveling, an electric vehicle in which an electric motor is mounted, a hybrid vehicle in which an internal combustion engine and an electric motor are mounted, or the like. Furthermore, the electric vehicle includes a fuel cell vehicle equipped with a fuel cell.

  The vehicle 10 detects the driving support device 12 that supports operation of acceleration / deceleration, braking, and steering, and the gripping state (gripping or non-gripping) of the driver with respect to the steering wheel 28, and issues an alarm when non-gripping is detected. It has a grasping state detection device 40 that emits.

[1.2 Driving support device 12]
As shown in FIG. 1, the driving support device 12 includes a support information acquisition unit 14, a driving support ECU 16, an acceleration / deceleration device 18, a braking device 20, and a steering device 22.

  The support information acquisition unit 14 includes a plurality of devices that detect various types of information necessary for driving support. Here, for example, a plurality of sensors for detecting various vehicle states (a touch sensor 42, a torque sensor 46, a vehicle speed sensor 50, etc., which will be described later), a camera and radar (not shown) for acquiring information inside and outside the vehicle, A satellite navigation device (not shown) such as GPS is included. This also includes various ECUs (a touch sensor ECU 44, a torque sensor ECU 48, a vehicle speed sensor ECU 52, etc., which will be described later) that calculate sensor measurement results based on signals input from the sensors and the like.

  The driving support ECU 16 is a computer including a microcomputer (not shown). The microcomputer includes an input / output unit including an A / D converter, a D / A converter, and the like, an arithmetic unit including a CPU, and a storage unit (all not shown) including a ROM, a RAM, and the like. The calculation unit functions as various function realizing units when the CPU executes various programs stored in the storage unit. The driving assistance ECU 16 may be composed of one ECU or a plurality of ECUs. The driving support ECU 16 acquires various types of information from the support information acquisition unit 14 and calculates a driving support amount according to the driving support function being executed. Then, a control signal corresponding to the calculation result is output to the drive ECU of the acceleration / deceleration device 18, the brake ECU of the brake device 20, and the steering ECU 24 of the steering device 22.

  The acceleration / deceleration device 18 includes a drive control device including a drive ECU and a drive source for travel (none of which is shown). The drive control device increases or decreases the operation amount of the drive source in accordance with an operation amount of an accelerator pedal (not shown) or a driving support amount calculated by the driving support ECU 16.

  The braking device 20 includes a brake control device including a braking ECU and a brake (none of which are shown). The brake control device controls the operation amount of the brake according to the operation amount of a brake pedal (not shown) or the driving support amount calculated by the driving support ECU 16.

  The steering device 22 includes an electric power steering device (an electric motor 26, a steering wheel 28, a steering shaft 30, etc.) including a steering ECU 24, and a steering wheel 32. The electric power steering device controls the steering angle of the steered wheels 32 according to the operation amount of the steering wheel 28 or the driving support amount calculated by the driving support ECU 16.

[1.3 Grasping state detection device 40]
As shown in FIG. 1, the gripping state detection device 40 includes a touch sensor 42, a touch sensor ECU 44, a torque sensor 46, a torque sensor ECU 48, a vehicle speed sensor 50, a vehicle speed sensor ECU 52, an alarm ECU 54, and an alarm device 56. Among these, the touch sensor 42, the touch sensor ECU 44, the torque sensor 46, the torque sensor ECU 48, the vehicle speed sensor 50, and the vehicle speed sensor ECU 52 are included in the support information acquisition unit 14 described above.

  The touch sensor 42 detects the contact state of the driver with respect to the rim portion 28a of the steering wheel 28, and outputs a contact signal corresponding to the contact state. The touch sensor 42 is formed, for example, by applying a conductive paint to the surface layer of the rim portion 28a. In addition to the conductive paint, a pressure sensor may be provided on the surface layer of the rim portion 28a. In this specification, a state where the driver is touching the steering wheel 28 (touch sensor 42) is referred to as “hands-on”, and a state where the driver is not touching is referred to as “hands-off”. The touch sensor ECU 44 is a computer including a microcomputer, like the driving support ECU 16. The touch sensor ECU 44 detects the presence or absence of the driver's contact with the touch sensor 42 based on the contact signal output from the touch sensor 42 and outputs detection information. In this specification, the touch sensor 42 and the touch sensor ECU 44 are referred to as “hands-on detection devices”.

  The torque sensor 46 detects the steering torque Tr acting on the steering shaft 30 and outputs a torque signal corresponding to the steering torque Tr. The torque sensor ECU 48 is a computer including a microcomputer, like the driving support ECU 16. The torque sensor ECU 48 detects the steering torque Tr acting on the steering shaft 30 based on the torque signal output from the torque sensor 46, and outputs detection information. In this specification, the torque sensor 46 and the torque sensor ECU 48 are referred to as “torque detection devices”.

  The vehicle speed sensor 50 detects the vehicle speed V of the vehicle 10 and outputs a vehicle speed signal corresponding to the vehicle speed V. The vehicle speed sensor ECU 52 is a computer including a microcomputer, like the driving support ECU 16. The vehicle speed sensor ECU 52 detects the traveling speed of the vehicle 10 based on the vehicle speed signal output from the vehicle speed sensor 50 and outputs detection information.

  The alarm ECU 54 is a computer including a microcomputer, like the driving support ECU 16. The microcomputer includes an input / output unit 62 including an A / D converter and a D / A converter, an arithmetic unit 64 including a CPU, and a storage unit 66 including a ROM and a RAM. The calculation unit 64 functions as a gripping state detection unit 68 and an alarm control unit 70 when the CPU executes various programs stored in the storage unit 66. The alarm ECU 54 may be composed of one ECU or a plurality of ECUs.

  The gripping state detection unit 68 detects the gripping state (gripping or non-gripping) of the driver with respect to the steering wheel 28 based on each detection information output from the touch sensor ECU 44 and the torque sensor ECU 48. Further, the driver's driving intention (with or without driving intention) is determined based on the gripping state. The alarm control unit 70 outputs an alarm signal or an alarm stop signal based on the detection result of the gripping state detection unit 68.

  The alarm device 56 is a notification device that issues a hand-off alarm to the driver. In the present embodiment, a multi-information display provided in the meter is used as the alarm device 56. The alarm device 56 displays an alarm mark 72 when an alarm signal output from the alarm ECU 54 is received, and hides the alarm mark 72 when an alarm stop signal output from the alarm ECU 54 is received.

  As the alarm device 56, an acoustic device that emits an alarm sound can be used. In addition, the steering wheel 28 may be vibrated by operating the electric motor 26 of the steering device 22. Similarly, a seat belt or an accelerator pedal may be vibrated.

[1.4 Alarm processing]
Alarm processing performed in the vehicle 10 (the driving support device 12 and the gripping state detection device 40) will be described with reference to FIG. A series of processing described below is periodically performed. The touch sensor 42 periodically outputs a contact signal, the torque sensor 46 periodically outputs a torque signal, and the vehicle speed sensor 50 periodically outputs a vehicle speed signal.

  In step S <b> 1, the gripping state detection unit 68 determines whether or not the driving support ECU 16 is performing driving support related to steering. As driving assistance related to steering, for example, there is lane maintenance assistance that assists the steering operation so that the vehicle 10 travels substantially in the center of the traveling lane. In addition, there is an out-of-road departure suppression support that alerts the driver by steering vibration when the vehicle 10 is likely to depart from the traveling lane, and intervenes in the steering operation and assists returning to the traveling lane when there is no departure avoidance operation. . In addition, there is a traffic jam driving support that performs lane keeping support while maintaining a set vehicle speed or an appropriate inter-vehicle distance from a preceding vehicle during traffic jams (during low speed driving). If the driving support ECU 16 is providing driving support (step S1: YES), the process proceeds to step S2. On the other hand, when the driving support ECU 16 is not performing driving support (step S1: NO), the subsequent processing is not performed.

  When the process proceeds from step S1 to step S2, the driving assistance ECU 16 determines whether or not the alarm ECU 54 is operating normally. The determination of normal operation will be described later (see [1.7]). If alarm ECU 54 is operating normally (step S2: YES), the process proceeds to step S3. On the other hand, if alarm ECU 54 is not operating normally (step S2: NO), the process proceeds to step S12.

  When the process proceeds from step S2 to step S3, the gripping state detection unit 68 determines whether or not the hands-on detection device and the torque detection device are operating normally. The determination of normal operation will be described later (see [1.7] below). When the hands-on detection device and the torque detection device are operating normally (step S3: YES), the process proceeds to step S4. On the other hand, when at least one of the hands-on detection device and the torque detection device is not operating normally (step S3: NO), the process proceeds to step S9.

  When the process proceeds from step S3 to step S4, a hands-on determination process is performed. Details of the hands-on determination process will be described later (see [1.5] below). In the hands-on determination process, the first flag FLG1 is set to 1 (gripping) when a hands-on is detected, and the first flag FLG1 is set to 0 (non-gripping) when a hands-off is detected.

  In step S5, a first torque determination process is performed. Details of the first torque determination process will be described later (see [1.6] below). In the first torque determination process, when the steering input is detected, the second flag FLG2 is set to 1 (gripping), and when the steering input is not detected, the second flag FLG2 is set to 0 (non-gripping).

  In step S6, the gripping state detection unit 68 determines the gripping state of the driver with respect to the steering wheel 28 based on the gripping state detection result, that is, the result of the hands-on determination process and the result of the torque determination first process. For example, the following processing is performed.

  The storage unit 66 stores gripping / driving intention determination information 80 as shown in FIG. 3A in advance. The grip / driving intention determination information 80 corresponds to the result of the hands-on determination process (first flag FLG1) and the result of the first torque determination process (second flag FLG2), the grip state determined from each result, and the driving intention. Information. The gripping state detection unit 68 detects the driver's gripping state and driving intention with respect to the steering wheel 28 based on the gripping / driving intention determination information 80. Specifically, when both the first flag FLG1 and the second flag FLG2 are 0 (non-gripping), it is detected that there is no driving intention without gripping (step S6: non-gripping). In this case, the process proceeds to step S7. On the other hand, when at least one of the first flag FLG1 and the second flag FLG2 is 1 (gripping), it is detected that there is an intention to drive by gripping (step S6: gripping). In this case, the process proceeds to step S8.

  When the process proceeds from step S6 to step S7, the alarm control unit 70 outputs an alarm signal in order to prompt the driver to hold the steering wheel 28. The alarm device 56 displays an alarm mark 72 when an alarm signal is received.

  When the process proceeds from step S6 to step S8, the alarm control unit 70 outputs an alarm stop signal. The alarm device 56 does not display the alarm mark 72 when an alarm stop signal is received.

  When the process proceeds from step S3 to step S9, the gripping state detection unit 68 determines whether the torque detection device is operating normally. The determination of normal operation will be described later (see [1.7] below). When the torque detection device is operating normally (step S9: YES), the process proceeds to step S10. On the other hand, when the torque detection device is not operating normally (step S9: NO), the process proceeds to step S12.

  When the process proceeds from step S9 to step S10, the first torque determination process is performed as in step S5. In step S11, the gripping state detection unit 68 compares the vehicle speed V with the vehicle speed threshold value V_th. Step S11 will be described with reference to FIG.

  In addition to the driver's steering operation, vibration components due to various vibration factors (such as drive sources and road surface irregularities) are input to the steering device 22. The relationship between the frequency f and the steering torque Tr is shown in FIGS. 4A and 4B when the vibration component is the frequency f. Of the vibration components, the frequency f caused by the driver's steering operation is about several [Hz], and the frequency f caused by vibration of the drive source and road surface irregularities is several tens [Hz]. The frequencies f1 to f2 shown in FIG. 4A are frequency bands for the driver's steering operation, and are approximately 0.3 to 2 [Hz].

  When the vehicle 10 travels at a medium speed or higher, as shown in FIG. 4A, there is a certain degree between the frequency characteristic A when the driver does not let go and the frequency characteristic B when he has let go. A torque difference Trd is generated. Therefore, as described in [1.6] below, by comparing this torque difference Trd with a predetermined torque difference threshold value Trd_th, it is determined whether the driver is steering input, that is, the steering wheel 28 is gripped. It can be determined whether or not. On the other hand, when the vehicle 10 travels at a low speed, the torque difference Trd between the frequency characteristic A ′ and the frequency characteristic B tends to be small, as shown in FIG. 4B. For this reason, the reliability of the grip detection method by comparing the magnitude relationship between the torque difference Trd and the predetermined torque difference threshold value Trd_th is lowered.

  For this reason, in step S11, the processing to be performed later is changed according to the vehicle speed V. When the vehicle speed V is low, that is, when the vehicle speed V is less than the vehicle speed threshold value V_th stored in the storage unit 66 (step S11: YES), the process proceeds to step S12. When the vehicle speed V is equal to or higher than the medium speed, that is, when the vehicle speed V is equal to or higher than the vehicle speed threshold value V_th stored in the storage unit 66 (step S11: NO), the process proceeds to step S6.

  When the process proceeds from step S11 to step S6, the gripping state detection unit 68 determines the gripping state of the driver with respect to the steering wheel 28 based on the gripping state detection result, that is, the result of the torque determination first process. For example, the following processing is performed.

  The storage unit 66 stores gripping / driving intention determination information 82 as shown in FIG. 3B in advance. The grip / driving intention determination information 82 is information in which the result of the first torque determination process (second flag FLG2) is associated with the grip state determined from the result and the driving intention. The gripping state detection unit 68 detects the driver's gripping state and driving intention with respect to the steering wheel 28 based on the gripping / driving intention determination information 82. Specifically, when the second flag FLG2 is 0 (non-gripping), it is detected that there is no driving intention without gripping (step S6: non-gripping). In this case, the process proceeds to step S7. On the other hand, when the second flag FLG2 is 1 (gripping), it is detected that there is an intention to drive by gripping (step S6: gripping). In this case, the process proceeds to step S8.

  When the process proceeds from step S2 or step S11 to step S12, a driving assistance stop instruction is output from the alarm ECU 54 to the driving assistance ECU 16. At this time, the driving support ECU 16 stops the driving support being executed.

[1.5 Hands-on judgment processing]
The hands-on determination process will be described with reference to FIG. In step 21, the grip state detection unit 68 determines the contact state of the driver with respect to the steering wheel 28 based on the detection information transmitted from the touch sensor ECU 44. When contact, that is, hands-on is detected (step S21: YES), the process proceeds to step S22. On the other hand, when non-contact, that is, hands-off is detected (step S21: NO), the process proceeds to step S23.

  When the process proceeds from step S21 to step S22, the gripping state detection unit 68 sets the first flag FLG1 to 1 (gripping). When the process proceeds from step S21 to step S23, the gripping state detection unit 68 sets the first flag FLG1 to 0 (not gripped).

[1.6 Torque determination first process]
The torque determination first process will be described with reference to FIG. In step 31, the gripping state detection unit 68 subtracts a predetermined reference torque Tr_s from the detection information transmitted from the torque sensor ECU 48, here the steering torque Tr, to obtain a torque difference Trd. The reference torque Tr_s is a value serving as a guide for torque generated in the steering shaft 30 when there is no steering input to the steering wheel 28 and is stored in the storage unit 66 in advance.

  In step S32, the gripping state detection unit 68 compares the torque difference Trd with the torque difference threshold value Trd_th stored in the storage unit 66 in advance, whereby the steering state of the driver with respect to the steering wheel 28 (with or without steering input). Determine. If the torque difference Trd is greater than or equal to the torque difference threshold Trd_th, that is, if there is a steering input (step S32: YES), the process proceeds to step S33. On the other hand, when the torque difference Trd is less than the torque difference threshold Trd_th, that is, when there is no steering input (step S32: NO), the process proceeds to step S34.

  When the process proceeds from step S32 to step S33, the gripping state detection unit 68 sets the second flag FLG2 to 1 (gripping). When the process proceeds from step S32 to step S34, the gripping state detection unit 68 sets the second flag FLG2 to 0 (not gripped).

[1.7 Normal operation judgment]
[1.7.1 Processing of alarm ECU 54]
The determination of normal operation performed by the alarm ECU 54 will be described by taking normal determination of the hands-on detection device as an example. The touch sensor 42 periodically transmits a contact signal to the touch sensor ECU 44, and the touch sensor ECU 44 periodically transmits detection information to the alarm ECU 54. The touch sensor ECU 44 adds a code to the detection information when transmitting the detection information, and further periodically changes the code.

  For example, at the time point n, the touch sensor ECU 44 transmits detection information Xa in which a symbol a is added to the information X indicated by the contact signal transmitted from the touch sensor 42. Next, at time point n + 1, the detection information Xb with the code b added to the information X is transmitted. Next, at time point n + 2, the detection information Xc with the code c added to the information X is transmitted. Next, at the time point n + 3, the detection information Xa with the code a added to the information X is transmitted. Thereafter, the codes b, c, and a are sequentially changed and added to the information X, and the detection information Xa, Xb, and Xc are sequentially transmitted.

  When an abnormality occurs in the touch sensor 42, the information X itself indicated by the contact signal of the touch sensor 42 becomes abnormal. The alarm ECU 54 detects that an abnormality has occurred in the touch sensor 42 by detecting that the information X is abnormal. On the other hand, when an abnormality occurs in the touch sensor ECU 44, detection information (for example, detection information Xa) having the same sign is repeatedly transmitted. The alarm ECU 54 detects that an abnormality has occurred in the touch sensor ECU 44 by repeatedly receiving detection information with the same sign.

[1.7.2 Processing of Driving Support ECU 16]
The determination of normal operation performed by the driving support ECU 16 will be described by taking normal determination of a hands-on detection device as an example. The alarm ECU 54 periodically transmits the detection information transmitted from the touch sensor ECU 44 to the driving support ECU 16. As with the touch sensor ECU 44, the alarm ECU 54 adds a code to the detection information when transmitting the detection information, and further periodically changes the code.

  For example, the alarm ECU 54 transmits detection information Xad obtained by adding a symbol d to the detection information Xa transmitted from the touch sensor ECU 44 at time point m. Next, at time point m + 1, the detection information Xbe with the sign e added to the detection information Xb is transmitted. Next, at time point m + 2, the detection information Xcf in which the code f is added to the detection information Xc is transmitted. Next, at time point m + 3, detection information Xad obtained by adding symbol d to detection information Xa is transmitted. Thereafter, the detection information Xa, Xb, and Xc are sequentially changed and added with the symbols e, f, and d, and the detection information Xad, Xbe, and Xcf are sequentially transmitted.

  The driving assistance ECU 16 detects that an abnormality has occurred in the touch sensor 42 by detecting that the information X is abnormal. The driving assistance ECU 16 detects that an abnormality has occurred in the touch sensor ECU 44 by repeatedly receiving the detection information of the same sign added by the touch sensor ECU 44. Further, by repeatedly receiving the detection information of the same sign added by the alarm ECU 54, it is detected that an abnormality has occurred in the alarm ECU 54.

  Note that the alarm ECU 54 and the driving support ECU 16 also perform normal operation determination for the torque detection device, similar to the hands-on detection device. However, the torque sensor ECU 48 adds a code different from the code added to the detection information by the touch sensor ECU 44 to the detection information. Further, the alarm ECU 54 makes the code added to the detection information transmitted from the touch sensor ECU 44 different from the code added to the detection information transmitted from the torque sensor ECU 48.

[1.8 Summary of First Embodiment]
The gripping state detection device 40 includes a touch sensor 42 that detects a contact state of the driver with respect to the steering wheel 28, a torque sensor 46 that detects the steering torque Tr, and a detection result of the touch sensor 42 and the torque sensor 46. And a gripping state detector 68 for detecting the gripping state of the steering wheel 28.

  According to this configuration, when the driver grips the rim portion 28a that is a touch sensor forming portion, at least the touch sensor 42 can detect the driver's contact with the steering wheel 28. Further, when the driver grips the spoke portion 28b other than the rim portion 28a, for example, the driver's steering input can be detected by the torque sensor 46. Therefore, the gripping state of the steering wheel 28 can be detected with high accuracy regardless of the gripping position of the driver.

  The grip state detection unit 68 detects the driver's intention to drive based on the grip state of the steering wheel 28 by the driver. The gripping state detection device 40 outputs an alarm signal when the gripping state detection unit 68 detects that the driver does not have a driving intention, and issues an alarm when the warning signal is received. And an alarm device 56.

  According to this configuration, the driver's intention to drive can be determined based on the gripping state of the steering wheel 28, and when the driver does not have the driver's intention to drive, in this case, the driver is prompted to grip the steering wheel 28. it can.

  The gripping state detection unit 68 obtains a torque difference Trd between the steering torque Tr detected by the torque sensor 46 and a predetermined reference torque Tr_s. When the torque difference Trd is greater than or equal to a predetermined torque difference threshold Trd_th, the steering wheel 28 Detects gripping.

  According to this configuration, the presence or absence of gripping can be appropriately determined by comparing the torque difference Trd between the steering torque Tr and the reference torque Tr_s with the predetermined torque difference threshold value Trd_th.

[2 Second Embodiment]
In the second embodiment, a part of the processing performed in the first embodiment is changed, and the configuration shown in FIG. 1 can be used as the device configuration itself. The vehicle 10 ′ according to the second embodiment has a gripping state detection device 40 ′, and the gripping state detection device 40 ′ has an alarm ECU 54 ′. The alarm ECU 54 ′ has a calculation unit 64 ′, and the calculation unit 64 ′ functions as the gripping state detection unit 68 ′ and the alarm control unit 70 by executing a program stored in the storage unit 66 ′.

[2.1 Alarm processing of gripping state detection device 40 ']
The alarm process performed by the gripping state detection device 40 ′ according to the second embodiment will be described with reference to FIG. Note that many of the processes performed by the gripping state detection device 40 ′ according to the second embodiment are common to the processes performed by the gripping state detection device 40 according to the first embodiment. For this reason, description of common processing is omitted. Specifically, the processes in steps S41 to S49 and S51 shown in FIG. 7 are the same as the processes in steps S1 to S9 and S12 shown in FIG. However, in the description of each common process, “vehicle 10, gripping state detection device 40, alarm ECU 54, storage unit 66, gripping state detection unit 68” is referred to as “vehicle 10 ′, gripping state detection device 40 ′, and alarm ECU 54 ′. , Storage unit 66 ′, grasping state detection unit 68 ′ ”.

  The characteristic part of the second embodiment is the second torque determination process in step S50. In the second torque determination process, the second flag FLG2 is set to 1 (gripping) when the steering input is detected, and the second flag FLG2 is set to 0 (non-gripping) when the steering input is not detected. When step S50 ends, the processing moves to step S46 uniformly.

[2.2 Torque determination second process]
The torque determination second process will be described with reference to FIG. In step S61, the gripping state detection unit 68 ′ compares the vehicle speed V with the vehicle speed threshold value V_th. As described with reference to FIGS. 4A and 4B, when the vehicle 10 travels at a low speed, the reliability of the grip detection method by comparing the magnitude relationship between the torque difference Trd and the predetermined torque difference threshold Trd_th becomes low. . For this reason, in the first embodiment, the driving support itself is stopped at a low speed when the reliability is lowered (step S12 in FIG. 2). On the other hand, in the second embodiment, processing for compensating for the decrease in reliability is performed.

  When the vehicle speed V is low, that is, when it is less than the vehicle speed threshold value V_th stored in the storage unit 66 ′ (step S61: YES), the process proceeds to step S62. When the vehicle speed V is equal to or higher than the medium speed, that is, when the vehicle speed V is equal to or higher than the vehicle speed threshold value V_th stored in the storage unit 66 ′ (step S61: NO), the process proceeds to step S63.

  When the process proceeds from step S61 to step S62, the gripping state detection unit 68 ′ sets the first torque difference threshold value Trd_th1 (<second torque difference threshold value Trd_th2) as the torque difference threshold value Trd_th. On the other hand, when the process proceeds from step S61 to step S63, the gripping state detection unit 68 ′ sets the second torque difference threshold value Trd_th2 (> first torque difference threshold value Trd_th1) as the torque difference threshold value Trd_th. The first torque difference threshold value Trd_th1 and the second torque difference threshold value Trd_th2 are stored in advance in the storage unit 66 ′. As described above, when the vehicle speed V is low (V <V_th), the torque difference threshold Trd_th used in the torque determination is reduced to reduce the frequency characteristic A ′ and the frequency characteristic B as shown in FIG. Even if the torque difference Trd is small, the presence / absence of steering input can be determined. Here, although the torque difference threshold value Trd_th is changed between the low speed and the medium speed or higher, three or more vehicle speed ranges may be set, and a different torque difference threshold value Trd_th may be set for each vehicle speed range.

  Since the process of step S64-step S67 is common with the process of step 31-step S34 shown in FIG. 6, the description is abbreviate | omitted here.

[2.3 Summary of Second Embodiment]
The gripping state detection device 40 ′ includes a vehicle speed sensor 50 that detects the vehicle speed V. When the vehicle speed V detected by the vehicle speed sensor 50 is less than the vehicle speed threshold V_th (predetermined vehicle speed), the gripping state detection unit 68 ′ is a torque between the steering torque Tr detected by the torque sensor 46 and the predetermined reference torque Tr_s. The difference Trd is obtained. Then, when the torque difference Trd is greater than or equal to the first torque difference threshold value Trd_th1 (first torque difference), it is detected that the steering wheel 28 is gripped. Further, when the vehicle speed V detected by the vehicle speed sensor 50 is equal to or higher than the vehicle speed threshold value V_th, a torque difference Trd between the steering torque Tr detected by the torque sensor 46 and the reference torque Tr_s is obtained. Then, when the torque difference Trd is equal to or larger than the second torque difference threshold value Trd_th2 (second torque difference) larger than the first torque difference threshold value Trd_th1, it is detected that the steering wheel 28 is gripped.

  According to this configuration, the torque difference threshold Trd_th to be compared with the torque difference Trd between the steering torque Tr and the reference torque Tr_s is changed according to the vehicle speed V, so the torque difference Trd between the steering torque Tr and the reference torque Tr_s becomes small. Even if the vehicle 10 ′ is traveling at a low speed (V <V_th), it is possible to appropriately determine whether or not the vehicle is gripped.

[3 Modifications]
As described with reference to FIGS. 4A and 4B, when the vehicle 10 travels at a low speed, the grip detection method is performed by comparing the magnitude relationship between the torque difference Trd and the predetermined torque difference threshold value Trd_th, that is, by a torque detection device. The reliability of grip detection is lowered. Therefore, grip detection by the torque detection device may be stopped at a low speed. For example, when the vehicle speed V is detected and the vehicle speed V is less than the vehicle speed threshold V_th, grip detection by the hands-on detection device may be performed while grip detection by the torque detection device may be stopped.

  When there is a steering intervention by automatic driving or the like, when the vehicle speed V is low, almost no operation by the driver is required. Then, since the torque difference Trd is less likely to occur between the steering torque Tr generated by the vehicle 10 ′ and the steering torque Tr generated by the driver operating the steering wheel 28, gripping by a torque detection device such as the torque sensor 46 is performed. The reliability of detection decreases. According to this configuration, since the grip detection by the torque detection device is stopped at a low speed when the reliability of the grip detection by the torque detection device such as the torque sensor 46 is lowered, it is possible to appropriately determine the presence or absence of gripping.

  It should be noted that the gripping state detection device 40 according to the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10, 10 '... Vehicle 12 ... Driving assistance device 16 ... Driving assistance ECU 28 ... Steering wheel 40, 40' ... Grasping state detection device 42 ... Touch sensor 44 ... Touch sensor ECU 46 ... Torque sensor 48 ... Torque sensor ECU 54, 54 '… Alarm ECU
56 ... Alarm 68, 68 '... Holding state detector 70 ... Alarm controller

Claims (5)

A touch sensor that detects the contact state of the driver with the steering wheel;
A torque sensor for detecting steering torque;
A gripping state detection unit that detects a gripping state of the steering wheel by the driver based on detection results of the touch sensor and the torque sensor ;
A vehicle speed sensor for detecting the vehicle speed ,
The gripping state detector
When the vehicle speed detected by the vehicle speed sensor is less than a predetermined vehicle speed, while detecting the grip state based on the detection result of the touch sensor, stop the detection of the grip state based on the detection result of the torque sensor,
A gripping state detection device that detects a gripping state based on detection results of the touch sensor and the torque sensor when the vehicle speed detected by the vehicle speed sensor is equal to or higher than a predetermined vehicle speed . The gripping state detection device according to claim 1,
The gripping state detection unit detects the driver's intention to drive based on the gripping state of the steering wheel by the driver,
Further, an alarm control unit that outputs an alarm signal when the gripping state detection unit detects that the driver does not have a driving intention, and
A gripping state detection device comprising: an alarm device that issues an alarm when the alarm signal is received. In the holding state detection device according to claim 1 or 2,
The gripping state detector
A torque difference between the steering torque detected by the torque sensor and a predetermined reference torque is obtained, and when the torque difference is equal to or greater than a predetermined torque difference, it is detected that the steering wheel is gripped. A gripping state detection device. In the holding | grip state detection apparatus of any one of Claims 1-3 ,
The touch sensor is provided on a rim portion of the steering wheel. A gripping state detection device. In the holding | grip state detection apparatus of any one of Claims 1-4 ,
The touch sensor is formed of a conductive paint applied to the steering wheel. A gripping state detection device.

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