Contact detection device

Abstract

The present invention provides a technique capable of performing a failure diagnosis related to a capacitance sensor. The contact detection device includes: a capacitance sensor that is provided on a vehicle steering wheel and detects contact of a human body with the steering wheel; an inference mechanism that infers whether a human body is in contact with the steering wheel; and a diagnosis mechanism that performs a failure diagnosis related to the capacitance sensor based on a detection result of the capacitance sensor when the inference mechanism infers contact and a detection result of the capacitance sensor when the inference mechanism infers no contact.

Description

Technical Field

[0001] The present invention relates to a contact detection device. Background Art

[0002] There is known a detection device (such as Patent Document 1) that uses a capacitance sensor to determine whether a passenger in a vehicle is holding the steering wheel. The detection result is used, for example, for switching from autonomous driving to manual driving, driving assistance, etc.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-203660 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] When there is a fault such as a disconnection in the circuit of the capacitance sensor, the capacitance changes, which affects the detection accuracy. For example, in the case of an open-circuit fault where the ground wire is disconnected, the reference potential changes, which affects the detection accuracy.

[0008] An object of the present invention is to provide a technique capable of performing fault diagnosis related to a capacitance sensor.

[0009] Means for Solving the Problems

[0010] According to the present invention, there is provided a contact detection sensor, characterized in that

[0011] the contact detection sensor includes:

[0012] a capacitance sensor that is provided on a steering wheel of a vehicle and detects contact of a human body with the steering wheel; a determination mechanism that determines whether a human body is in contact with the steering wheel; and

[0013] a diagnosis mechanism that performs fault diagnosis related to the capacitance sensor based on a detection result of the capacitance sensor when the determination mechanism determines contact and a detection result of the capacitance sensor when the determination mechanism determines non-contact.

[0014] Advantages of the Invention

[0015] According to the present invention, a technique capable of performing fault diagnosis related to a capacitance sensor can be provided. Brief Description of the Drawings

[0016] Figure 1 is a block diagram of a vehicle and a control device.

[0017] Figure 2 is a flowchart showing a processing example executed by a control device of Figure 1 .

[0018] Figure 3 Among them, (A) is a schematic diagram of a steering wheel in a neutral position, Figure 3 and (B) among them is Figure 3 a sectional view taken along line A-A of (A) among them and a block diagram of a contact detection device according to an embodiment of the present invention.

[0019] Figure 4 is a flowchart showing an example of contact determination processing.

[0020] Figure 5 is a graph showing the results of a capacitance change test example in a normal state and an open circuit fault state.

[0021] Figure 6 is a flowchart showing an example of fault diagnosis processing.

[0022] Figure 7 is a graph showing an example of history information.

[0023] Explanation of reference numerals:

[0024] V: Vehicle; ST: Steering wheel; 22: ECU; 36: Capacitance sensor; 100: Contact detection device. Detailed Description of the Invention

[0025] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments are not limited to the invention related to the technical solution, and in addition, the combination of all features described in the embodiments is not necessarily required for the invention. Among the multiple features described in the embodiments, two or more features can be arbitrarily combined. In addition, the same or similar components are labeled with the same reference numerals, and repeated descriptions are omitted.

[0026] Figure 1 is a block diagram of a vehicle V and its control device 1 to which the present invention can be applied. In Figure 1 , the outline of the vehicle V is shown by a top view and a side view. As an example, the vehicle V is a sedan-type four-wheel passenger vehicle.

[0027] The vehicle V of the present embodiment is, for example, a parallel hybrid vehicle. In this case, the power device 50 is a traveling drive unit that outputs a driving force for rotating the drive wheels of the vehicle V, and can include an internal combustion engine, a motor, and an automatic transmission. The motor can be used as a drive source for accelerating the vehicle V and can be used as a generator (regenerative braking) during deceleration or the like.

[0028] <Control Device>

[0029] Refer to Figure 1 The configuration of the control device 1 for the vehicle V will be described. The control device 1 includes an ECU group (control unit group) 2. The ECU group 2 includes a plurality of ECUs 20 to 29 configured to be able to communicate with each other. Each ECU includes a processor represented by a CPU, a storage device such as a semiconductor memory, and an interface with external devices. Programs executed by the processor, data used by the processor in processing, etc. are stored in the storage device. Each ECU may include a plurality of processors, storage devices, and interfaces, etc. It should be noted that the number of ECUs and the functions they are responsible for can be appropriately designed, and can be more refined or integrated than in this embodiment. It should be noted that in Figure 1 the names of the representative functions of the ECUs 20 to 29 are marked. For example, the ECU 20 is expressed as "driving ECU".

[0030] The ECU 20 executes control related to driving assistance including the autonomous driving of the vehicle V. In autonomous driving, the driving (such as acceleration of the vehicle V implemented by the power device 50), steering, and braking of the vehicle V are automatically performed without the operation of the passenger. In addition, in manual driving, the ECU 20 can execute driving assistance controls such as collision mitigation braking and lane departure suppression. In the case where a collision with an obstacle ahead is likely to occur, the collision mitigation braking instructs the operation of the braking device 51 to assist in avoiding the collision. In the case where the vehicle V is likely to deviate from the driving lane, the lane departure suppression instructs the operation of the electric power steering device 41 to assist in avoiding lane departure. In addition, the ECU 20 can execute the automatic following control that enables the vehicle V to automatically follow the vehicle ahead in both autonomous driving and manual driving. In the case of autonomous driving, all acceleration, deceleration, and steering of the vehicle V can be automatically performed. In the case of manual driving, the acceleration and deceleration of the vehicle V can also be automatically performed.

[0031] The EUC 21 is an environment recognition unit that recognizes the driving environment of the vehicle V based on the detection results of the detection units 31A, 31B, 32A, and 32B that detect the surrounding conditions of the vehicle V. In the case of this embodiment, the detection units 31A and 31B are cameras that photograph the front of the vehicle V (hereinafter, sometimes expressed as camera 31A and camera 31B). By analyzing the images captured by the cameras 31A and 31B, the outline of the target object and the lane dividing lines (such as white lines) on the road can be extracted.

[0032] In the case of this embodiment, the detection unit 32A is a Light Detection and Ranging (hereinafter sometimes referred to as lidar 32A), which detects the objects around the vehicle V or measures the distance to the objects. In the case of this embodiment, five lidars 32A are provided, one is provided at each corner of the front part of the vehicle V, one is provided at the center of the rear part, and one is provided at each side of the rear part. The detection unit 32B is a millimeter-wave radar (hereinafter sometimes referred to as radar 32B), which detects the objects around the vehicle V or measures the distance to the objects. In the case of this embodiment, five radars 32B are provided, one is provided at the center of the front part of the vehicle V, one is provided at each corner of the front part, and one is provided at each corner of the rear part.

[0033] The ECU 22 is a steering control unit that controls the electric power steering device 41. The electric power steering device 41 includes a mechanism that steers the front wheels according to the driving operation (steering operation) of the driver on the steering wheel ST. The electric power steering device 41 includes: a drive unit 41a that includes a motor that generates a driving force (sometimes referred to as steering assist torque) for assisting the steering operation or automatically steering the front wheels; a steering angle sensor 41b; a torque sensor 41c that detects the steering torque (referred to as steering applied torque, different from the steering assist torque) borne by the driver, etc. In addition, the ECU 22 can obtain the detection result of the capacitance sensor 36 that detects whether the driver holds the steering wheel ST, and can monitor the holding state of the passenger on the steering wheel ST.

[0034] The ECU 23 is a braking control unit that controls the hydraulic pressure device 42. The braking operation of the driver on the brake pedal BP is converted into hydraulic pressure in the master cylinder BM and transmitted to the hydraulic pressure device 42. The hydraulic pressure device 42 is an actuator that can control the hydraulic pressure of the working oil supplied to the brake devices (such as disc brake devices) 51 provided on the four wheels based on the hydraulic pressure transmitted from the master cylinder BM. The ECU 23 drives and controls the solenoid valves and the like provided in the hydraulic pressure device 42. In addition, the ECU 23 can turn on the brake lamp 43B during braking. Thereby, the attention of the following vehicle to the vehicle V can be improved.

[0035] The ECU 23 and the hydraulic pressure device 42 can constitute an electric servo brake. The ECU 23 can, for example, control the distribution of the braking force applied by the four braking devices 51 and the braking force applied by the regenerative braking of the motor included in the power device 50. In addition, the ECU 23 can also implement the ABS function, traction control, and the attitude control function of the vehicle V based on the detection results of wheel speed sensors (not shown) respectively provided on the four wheels, a yaw rate sensor (not shown), and a pressure sensor 35 that detects the pressure in the brake master cylinder BM.

[0036] The ECU 24 is a passenger identification unit that detects the passengers in the vehicle based on the detection results of the passenger detection unit 42a that detects the passengers. The objects to be identified can be all the passengers or only the passengers sitting in the driver's seat (the driver). In the case of the present embodiment, the passenger detection unit 24a is a camera that photographs the interior of the vehicle (hereinafter, sometimes referred to as the camera 27a). It is possible to determine whether there are passengers in the vehicle based on the captured image of the camera 27a.

[0037] The ECU 25 is an in-vehicle notification control unit that controls the information output device 43A that notifies information to the interior of the vehicle. The information output device 43A includes, for example, a display device provided on a head-up display, an instrument panel, or an audio output device. It may also include a vibration device. The ECU 25 outputs various information such as the failure information of the vehicle V, the vehicle speed, and the outside air temperature, route guidance information, and information related to the state of the vehicle V to the information output device 43A, for example.

[0038] The ECU 26 is provided with a communication device 26a for vehicle-to-vehicle communication. The communication device 26a performs wireless communication with other surrounding vehicles and exchanges information between the vehicles.

[0039] The ECU 27 is a drive control unit that controls the power device 50. In the present embodiment, one ECU 27 is allocated to the power device 50, but one ECU can also be allocated to the internal combustion engine, the motor, and the automatic transmission respectively. The ECU 27 controls the output of the internal combustion engine and the motor or switches the gear of the automatic transmission, for example, based on the driving operations of the driver detected by the operation detection sensor 34a provided on the accelerator pedal AP and the operation detection sensor 34b provided on the brake pedal BP, the vehicle speed, and the like. It should be noted that the automatic transmission is provided with a rotational speed sensor 39 that detects the rotational speed of the output shaft of the automatic transmission as a sensor for detecting the driving state of the vehicle V. The vehicle speed of the vehicle V can be calculated based on the detection result of the rotational speed sensor 39.

[0040] The ECU 28 is a position recognition unit that recognizes the current position and travel route of the vehicle V. The ECU 28 controls the gyro sensor 33, GPS sensor 28b, and communication device 28c, and processes the detection results or communication results. The gyro sensor 33 detects the rotational movement of the vehicle V. The travel route of the vehicle V can be determined based on the detection results of the gyro sensor 33 and the like. The GPS sensor 28b detects the current position of the vehicle V. The communication device 28c performs wireless communication with a processor that provides map information and traffic information, and acquires this information. The database 28a can store high-precision map information, and the ECU 28 can more accurately determine the position of the vehicle V on the lane based on this map information and the like.

[0041] The ECU 29 is a control unit that performs opening / closing detection of the vehicle doors of the vehicle V and controls door locking. Each door of the vehicle V is equipped with an electric door locking device 29a that locks and unlocks the door, and an open detection sensor 29b that detects the opening and closing of the door. The ECU 29 controls the electric door locking device 29a to lock and unlock the door, and also identifies the opening and closing of the door by acquiring the detection results of the open detection sensor 29b.

[0042] The input device 45 is arranged inside the vehicle where the passenger can operate it, and accepts input of instructions and information from the passenger.

[0043] <Control Example>

[0044] A control example of the control device 1 will be described. Figure 2 It is a flowchart showing the mode selection process of the driving control executed by the ECU 20.

[0045] In S1, it is determined whether there is a selection operation of the mode from the passenger. For example, the passenger can switch the instruction between the automatic driving mode and the manual driving mode by operating the input device 45. If there is a selection operation, it proceeds to S2, and if there is no selection operation, the process ends.

[0046] In S2, it is determined whether the selection operation indicates automatic driving. If it indicates automatic driving, it proceeds to S3, and if it indicates manual driving, it proceeds to S4. In S3, the automatic driving mode is set, and the automatic driving control is started. In S4, the manual driving mode is set, and the manual driving control is started. The current setting related to the mode of the driving control is notified and identified from the ECU 20 to each of the ECUs 21 to 28.

[0047] In autonomous driving control, the ECU 20 outputs control commands to the ECU 22, ECU 23, and ECU 27 and controls the steering, braking, and driving of the vehicle V, causing the vehicle V to automatically travel regardless of the driving operation of the passenger. The ECU 20 sets the travel route of the vehicle V, refers to the position recognition result of the ECU 28 and the recognition result of the target object, and causes the vehicle V to travel along the set travel route. The target object is recognized based on the detection results of the detection units 31A, 31B, 32A, and 32B. In manual driving control, the driving, steering, and braking of the vehicle V are performed according to the driving operation of the driver, and the ECU 20 appropriately executes driving assistance control.

[0048] <Contact detection device>

[0049] Refer to Figure 3 in (A) and Figure 3 illustrate the contact detection device 100 according to an embodiment of the present invention with reference to (B) in. Figure 3 (A) in is a schematic diagram of the steering wheel ST in the neutral position. Figure 3 (B) in represents Figure 3 a sectional view taken along line A-A of (A) in and a block diagram of the configuration of the contact detection device 100.

[0050] The rim portion of the steering wheel ST includes a core 60 made of a conductive metal material. The core is grounded. The core 60 is covered with a resin 61 that is an insulator as a whole. A part of the resin 61 is covered with a capacitance sensor 36, and the remaining part is covered with an elastic member 62. Moreover, the capacitance sensor 36 and the elastic member 62 are covered with an outer skin 63 that is an insulator. The capacitance sensor 36 of the present embodiment is an electrode. The capacitance sensor 36 can be formed by a coating film of a conductive material or a sheet of a conductive material. The capacitance sensor 36 extends in the circumferential direction of the rim portion of the steering wheel ST.

[0051] A capacitor with a capacitance C1 is formed between the capacitance sensor 36 and the core 60. As Figure 3 shown in (B) in, when a human body contacts the rim portion of the steering wheel ST, a capacitor with a capacitance C2 is formed between the capacitance sensor 36 and the human body. The human body is grounded by contacting other parts of the vehicle V through a part of it.

[0052] The contact detection device 100 includes a capacitance sensor 36, a signal source 103 that applies an AC signal to the capacitance sensor 36, a current sensor 102 that detects the current between the capacitance sensor 36 and the signal source 103, and an ECU 22. The ECU 22 can control the signal source 103 and obtain the detection result of the current sensor 102. When the human body is not in contact with the rim portion of the steering wheel ST, the current sensor 102 detects a current proportional to the capacitance C1. When the human body is in contact with the rim portion of the steering wheel ST, the current sensor 102 detects a current proportional to the combined capacitance (=C1 + C2) of the capacitances C1 and C2. It is possible to determine whether the passenger is in contact (holding) or not in contact (not holding) with the steering wheel ST based on the detection result of the current sensor 102.

[0053] Figure 4 This shows an example of the determination process executed by the ECU 22. For example, when the control of the vehicle V switches from autonomous driving to manual driving, the ECU 22 performs this determination process to confirm whether the passenger is holding the steering wheel ST.

[0054] In S11, the ECU 22 drives the signal source 103 and then obtains the detection result of the current sensor 102. In S12, it is determined whether the detection result (capacitance) of the current sensor 102 exceeds a threshold value. If the detection result exceeds the threshold value, the process proceeds to S13 and the contact (holding) is set as the determination result. If the detection result is below the threshold value, the process proceeds to S14 and the non-contact (not holding) is set as the determination result.

[0055] <Fault diagnosis>

[0056] When there is a fault such as a disconnection in the circuit of the capacitance sensor 36, the capacitance changes, which affects the detection accuracy. For example, if the ground wire of the core 60 is disconnected and the core 60 is not grounded, in the case of an open circuit fault, the reference potential changes, which affects the detection accuracy. Figure 5 This shows the results of a capacitance change test example in the normal state and the open circuit fault state. When the human body is not in contact with the steering wheel ST, the detected capacitance is lower in the open circuit fault state than in the normal state. On the contrary, when the human body is in contact with the steering wheel ST, the detected capacitance is higher in the open circuit fault state than in the normal state.

[0057] According to this result, in Figure 4 the determination of whether the steering wheel ST is held or not held, in the case of an open circuit fault, it may be necessary to change the threshold value during the determination in Figure 4 S12.

[0058] In addition, it is possible to diagnose whether an open circuit fault has occurred based on the tendency of the test results. As an example, the difference in the detection results of the capacitance when not in contact and when in contact can be cited. As Figure 5 shown, a large gap occurs between the difference D1 in the detection results of the capacitance in the normal state and the difference D2 in the detection results of the capacitance in the open circuit fault state. Therefore, by comparing the difference D in the detection results of the capacitance with a predetermined threshold Dth (D1 < Dth < D2), if the relationship D > Dth holds, it can be determined that an open circuit fault has occurred (referred to as the difference determination method).

[0059] In addition, as another example, as Figure 5 shown, thresholds Cth1 and Cth2 are set. When the detection result of the capacitance in contact exceeds the threshold Cth1 and the detection result of the capacitance when not in contact is lower than the threshold Cth2, it can be determined that an open circuit fault has occurred (referred to as the individual determination method). The threshold Cth1 is set to be greater than the detection result of the capacitance in the normal state and when in contact, and the threshold Cth2 is set to be less than the detection result of the capacitance in the normal state and when not in contact.

[0060] Figure 6 An example of the fault diagnosis process executed by the ECU22 is shown. The ECU22 periodically executes the process in this figure, for example. In fault diagnosis, since the detection result of the capacitance cannot be used as a reference to determine whether a passenger is in contact with the steering wheel ST, it is inferred whether a passenger is in contact with the steering wheel ST, and fault diagnosis is performed based on the inference result and the detection result of the capacitance.

[0061] In S21, the ECU22 drives the signal source 103, and then obtains the detection result of the current sensor 102. In S22, it is inferred whether a human body is in contact with the steering wheel ST. It is possible to infer whether a human body (passenger) is in contact with the steering wheel ST based on the state of the vehicle V and the detection results of the sensors equipped on the vehicle V.

[0062] As an example, when no passenger is detected by the passenger detection unit 24a, since there is no one in the vehicle, it can be inferred that the human body is not in contact with the steering wheel ST. In addition, when a passenger is detected by the passenger detection unit 24a and the vehicle V is in motion, it can be inferred that the human body is in contact with the steering wheel ST (during driving). The ECU22 can obtain the detection result of the passenger detection unit 24a via the ECU24. In addition, the ECU22 can determine whether the vehicle V is in motion based on the information from the ECU20 and ECU27.

[0063] As other examples, when the locking implemented by the electric vehicle door locking device 29a is released and the opening of the vehicle door is not detected by the opening detection sensor 29b, it is considered that a passenger is about to enter the vehicle V, and thus it can be inferred that the human body is not in contact with the steering wheel ST. After the opening of the vehicle door is detected by the opening detection sensor 29b, when the vehicle V is in motion, it can be inferred that the human body is in contact with the steering wheel ST (while in motion). The ECU 22 can acquire the state of the electric vehicle door locking device 29a and the detection result of the opening detection sensor 29b via the ECU 29.

[0064] Furthermore, as other examples, when the vehicle V is in autonomous driving and the steering wheel ST rotates from the neutral position, since automatic steering is completed by the electric power steering device 41, it can be inferred that the human body is not in contact with the steering wheel ST. When the vehicle V is in manual driving and the steering wheel ST rotates from the neutral position, it can be inferred that the human body is in contact with the steering wheel ST (while driving). The ECU 22 can determine whether the vehicle V is in autonomous driving or manual driving based on the information from the ECU 20. In addition, the ECU 22 can determine whether the steering wheel ST rotates from the neutral position by acquiring the detection result of the steering angle sensor 41b.

[0065] In S23, when it is inferred that the human body is in contact with the steering wheel ST based on the inference result of S22, it proceeds to S24, and when it is inferred that the human body is not in contact with the steering wheel ST, it proceeds to S25. In S24, the detection result obtained in S21 is saved as the detection result at the time of contact inference. In S25, the detection result obtained in S21 is saved as the detection result at the time of non-contact inference. The saving of the detection results in S24 and S25, for example, is Figure 7 saved in the storage device provided in the ECU 22 in the form of the history information shown. In Figure 7 the example, the detection results of S24 and S25 are saved as "the current value". The value at the time of the previous fault diagnosis (the value determined to be normal) is saved as "the previous value".

[0066] In S26, it is determined whether a fault diagnosis can be performed. When both the detection result at the time of contact (S24) and the detection result at the time of non-contact (S25) exist, it is determined that a fault diagnosis can be performed. When it is determined that a fault diagnosis can be performed, it proceeds to S27. In S27, a fault diagnosis is performed. Here, in Figure 7 the history information, based on the detection results of the capacitance at the time of contact inference and the capacitance at the time of non-contact inference saved as "the current value", a fault diagnosis is performed.

[0067] As a diagnostic method, the above-mentioned difference determination method or the individual determination method may be used. In addition, both the difference determination method and the individual determination method may be used, and when a fault is determined to be a fault by either method, the fault is determined to be a fault. Alternatively, both the difference determination method and the individual determination method may be used, and when a fault is determined to be a fault by both methods, the fault is determined to be a fault.

[0068] The threshold value Dth when the difference determination method is adopted and the threshold values Cth1 and Cth2 when the individual determination method is adopted may be default values predetermined at the time of factory shipment of the vehicle V or may be based on Figure 7 Alternatively, these thresholds may be initially set to default values, and then Figure 7 After the "last value" of the history information, it can also be set to a value set based on the "last value" of the history information. When the threshold Dth is set based on the "last value" of the history information, for example, the value can be calculated based on the "last value" of the history information. Figure 5 The difference D1 is set as Dth = D1 + fixed value. In addition, when the thresholds Cth1 and Cth2 are set based on the "last value" of the history information, for example, the value at the time of contact inference based on the "last value" of the history information can be set as Cth1 = the value at the time of contact inference + fixed value, and the value at the time of non-contact inference can be set as Cth2 = the value at the time of non-contact inference - fixed value. The history information can be used to adaptively set the thresholds for individual differences in the detection accuracy of electrostatic capacitance and differences in passengers.

[0069] In S28, it is determined whether the diagnosis result of S27 is a fault. If it is determined to be normal, the process proceeds to S31. Figure 7 In the history information, the "last value" is updated with the "current value" and the processing is terminated. If it is determined to be a fault, the process proceeds to S29 to notify the passenger that the grip detection function of the steering wheel ST has a fault. The notification can be made via the ECU 25 and the information output device 43A. The notification can also be a notification to urge the passenger to have the vehicle inspected or repaired at a repair shop.

[0070] In S30, change Figure 4 In the case of an open circuit fault, when the human body is in contact with the steering wheel ST, the electrostatic capacity is larger than normal ( Figure 5 ). Therefore, for example, the threshold value is changed by adding a fixed value, or the threshold value is changed by subtracting a fixed value from the value at the time of contact inference of the "last value" of the history information. In this way, the grip determination of the steering wheel ST can be continued ( Figure 4 ).

[0071] As described above, according to the present embodiment, a technique capable of performing a failure diagnosis related to the capacitance sensor 36 can be provided. In the failure diagnosis, the detection results of the capacitance in two cases, i.e., when contact is inferred and when no contact is inferred, are used for diagnosis, so that the accuracy of the failure diagnosis can be improved. Although the detection results of the capacitance in two cases, i.e., when contact is inferred and when no contact is inferred, are used, these are generally information that can be obtained by the user of the vehicle V as long as the vehicle V is used once. Therefore, it is not necessary to spend a long time on the failure diagnosis.

[0072] <Summary of the embodiment>

[0073] 1. The contact detection device (100) of the above-described embodiment includes:

[0074] A capacitance sensor (36) provided on the steering wheel (ST) of the vehicle (V) and detecting contact of a human body with the steering wheel;

[0075] An inference mechanism (22, S22) for inferring whether a human body is in contact with the steering wheel; and

[0076] A diagnosis mechanism (22, S27) for performing a failure diagnosis related to the capacitance sensor based on the detection result of the capacitance sensor when the inference mechanism infers contact and the detection result of the capacitance sensor when the inference mechanism infers no contact.

[0077] According to this embodiment, a technique capable of performing a failure diagnosis related to the capacitance sensor can be provided. In the failure diagnosis, the detection results of the capacitance in two cases, i.e., when contact is inferred and when no contact is inferred, are used for diagnosis, so that the accuracy of the failure diagnosis can be improved. Although the detection results of the capacitance in two cases, i.e., when contact is inferred and when no contact is inferred, are used, these are generally information that can be obtained by the user of the vehicle as long as the vehicle is used once. Therefore, it is not necessary to spend a long time on the failure diagnosis.

[0078] 2. In the above-described embodiment,

[0079] The failure diagnosis is an open-circuit failure diagnosis of the wiring.

[0080] According to this embodiment, it is possible to detect a disconnection of a ground wire or the like that may occur in the rotating steering wheel ST.

[0081] 3. In the above-described embodiment,

[0082] The diagnosis mechanism performs the fault diagnosis based on the difference (D2) between the detection result of the capacitance sensor when the inference mechanism infers contact and the detection result of the capacitance sensor when the inference mechanism infers non-contact.

[0083] According to this embodiment, fault diagnosis can be performed based on the characteristics of the change in capacitance during a fault.

[0084] 4. In the above embodiment,

[0085] When the capacitance of the detection result of the capacitance sensor when the inference mechanism infers contact exceeds the first threshold (Cth1) and the capacitance of the detection result of the capacitance sensor when the inference mechanism infers non-contact is lower than the second threshold (Cth2), the diagnosis mechanism diagnoses a fault.

[0086] According to this embodiment, fault diagnosis is performed based on the characteristics of the change in capacitance during a fault.

[0087] 5. In the above embodiment,

[0088] Based on the detection result of the capacitance sensor before the diagnosis mechanism diagnoses a fault ( Figure 7 the last value), the first threshold and the second threshold are set.

[0089] According to this embodiment, the thresholds can be adaptively set for individual differences in the detection accuracy of capacitance and differences in passengers.

[0090] 6. In the above embodiment,

[0091] The vehicle is equipped with a passenger detection mechanism (24a) for detecting passengers inside the vehicle,

[0092] When no passenger is detected by the passenger detection mechanism, the inference mechanism infers that the human body is not in contact with the steering wheel,

[0093] When a passenger is detected by the passenger detection mechanism and the vehicle is in motion, the inference mechanism infers that the human body is in contact with the steering wheel.

[0094] According to this embodiment, the equipment and information of the vehicle can be effectively utilized to infer contact / non-contact.

[0095] 7. In the above embodiment,

[0096] The vehicle is equipped with an opening detection mechanism (29b) for detecting the opening of the door and a door locking mechanism (29a) for locking the door in a closed state,

[0097] When the lock implemented by the door locking mechanism is released and the opening of the door is not detected by the opening detection mechanism, the inference mechanism infers that the human body is not in contact with the steering wheel.

[0098] After the opening of the door is detected by the opening detection mechanism and the vehicle is in motion, the inference mechanism infers that the human body is in contact with the steering wheel.

[0099] According to this embodiment, the equipment and information of the vehicle can be effectively utilized to infer contact / non-contact.

[0100] 8. In the above embodiment,

[0101] The vehicle is a vehicle capable of autonomous driving,

[0102] When the vehicle is in autonomous driving and the steering wheel rotates from the neutral position, the inference mechanism infers that the human body is not in contact with the steering wheel,

[0103] When the vehicle is in manual driving and the steering wheel rotates from the neutral position, the inference mechanism infers that the human body is in contact with the steering wheel.

[0104] According to this embodiment, the equipment and information of the vehicle can be effectively utilized to infer contact / non-contact.

[0105] 9. The contact detection device of the above embodiment includes a notification mechanism (43A) for notifying the passenger of the diagnosis result of the diagnosis mechanism.

[0106] According to this embodiment, the passenger can be made aware of the occurrence of a failure, prompting the passenger to conduct inspections and repairs.

[0107] 10. The contact detection device of the above embodiment includes:

[0108] A determination mechanism (22, S12) that compares the detection result of the capacitance sensor with a threshold value to determine whether the human body is in contact with the steering wheel; and

[0109] A change mechanism (22, S30) that changes the threshold value based on the diagnosis result of the diagnosis mechanism.

[0110] According to this embodiment, it is also possible to determine the grip of the passenger on the steering wheel after a failure.

[0111] The embodiments of the invention have been described above, but the invention is not limited to the above embodiments, and various modifications and changes can be made within the scope of the gist of the invention.

Claims

1. A contact detection device, characterized in that: The contact detection device includes: A capacitance sensor, which is arranged on the steering wheel of the vehicle and detects the contact of the human body with the steering wheel; An inference mechanism, which infers whether the human body is in contact with the steering wheel; A diagnosis mechanism, which diagnoses an open circuit fault of the wiring of the capacitance sensor based on the detection result of the capacitance sensor when the inference mechanism infers contact and the detection result of the capacitance sensor when the inference mechanism infers non-contact; A determination mechanism, which compares the detection result of the capacitance sensor with a threshold value to determine whether the human body is in contact with the steering wheel; And A change mechanism, which changes the threshold value when the diagnosis mechanism determines an open circuit fault.

2. The contact detection device according to claim 1, characterized in that: The diagnosis mechanism diagnoses an open circuit fault based on the difference between the detection result of the capacitance sensor when the inference mechanism infers contact and the detection result of the capacitance sensor when the inference mechanism infers non-contact.

3. The contact detection device according to claim 1, characterized in that: When the capacitance, which is the detection result of the capacitance sensor when the inference mechanism infers contact, exceeds a first threshold value, and the capacitance, which is the detection result of the capacitance sensor when the inference mechanism infers non-contact, is lower than a second threshold value, the diagnosis mechanism determines an open circuit fault.

4. The contact detection device according to claim 3, characterized in that: The first threshold value and the second threshold value are set based on the detection result of the capacitance sensor before the diagnosis mechanism determines an open circuit fault.

5. The contact detection device according to claim 1, characterized in that: The vehicle is equipped with a passenger detection mechanism for detecting passengers in the vehicle. When no passenger is detected by the passenger detection mechanism, the inference mechanism infers that the human body is not in contact with the steering wheel. When a passenger is detected by the passenger detection mechanism and the vehicle is in motion, the inference mechanism infers that the human body is in contact with the steering wheel.

6. The contact detection device according to claim 1, characterized in that: The vehicle includes: An opening detection mechanism, which detects the opening of the vehicle door; and A door locking mechanism, which locks the vehicle door in a closed state. When the lock implemented by the door locking mechanism is released and the opening of the vehicle door is not detected by the detection mechanism, the inference mechanism infers that the human body is not in contact with the steering wheel. When the opening of the vehicle door is detected by the opening detection mechanism and the vehicle is in motion, the inference mechanism infers that the human body is in contact with the steering wheel.

7. The contact detection device according to claim 1, characterized in that: The vehicle is an autonomous vehicle. When the vehicle is in autonomous driving and the steering wheel rotates from the neutral position, the inference mechanism infers that the human body is not in contact with the steering wheel. When the vehicle is manually driven and the steering wheel rotates from the neutral position, the inference mechanism infers that a human body is in contact with the steering wheel.

8. The contact detection device according to claim 1, wherein: When the diagnosis mechanism determines an open circuit fault, the change mechanism changes the threshold value by adding a fixed value.

9. The contact detection device according to claim 1, wherein: The contact detection device includes a storage mechanism that stores the detection result of the capacitance sensor as history information when the inference mechanism infers that a human body is in contact with the steering wheel and the diagnosis mechanism determines that there is no open circuit fault. When the diagnosis mechanism determines an open circuit fault, the change mechanism changes the threshold value to a value obtained by subtracting a fixed value from the detection result stored as history information in the storage mechanism.

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