JP2011178336A - Driver awakening device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driver awakening deice capable of effectively awakening a driver. <P>SOLUTION: When detecting reduction in an awakening degree of the driver 100 by an awakening degree detecting device 70, by an arithmetic operation part 64, awakening degree reduction time target steering torque is calculated by adding a two-time differential value of a time change in a steering angle detected by a steering angle sensor 62 to target steering torque calculated by a target steering torque calculating part 63, and target assist torque is calculated by subtracting steering torque detected by a steering torque sensor 61 form the calculated awakening degree reduction time target steering torque. A control part 65 controls a motor 50 for steering a steered wheel (a left wheel W1 and a right wheel W2) based on the target assist torque calculated by the arithmetic operation part 64. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a driver awakening device that awakens a driver who drives a vehicle.

  Conventionally, as a technique in such a field, for example, there is one described in Patent Document 1. Here, in the steer-by-wire system in which the mechanical coupling between the steering member and the steered wheels is broken, when a decrease in the driver's arousal level is detected, only the steering member is vibrated with a large amplitude. Thus, it is described that the driver who puts his hand on the steering member is awakened. Further, it is described that the process of vibrating the steering member is performed when the vehicle is traveling straight, which is considered to have little influence on the traveling state of the vehicle.

JP 2004-034739 A

  By the way, the driver of the vehicle performs a fine steering operation and corrects the traveling direction of the vehicle even when the vehicle is traveling straight. However, in the above-described conventional device, when a fine steering operation is required to make the vehicle go straight, the steering member is vibrated to perform the process of awakening the driver, and effective while maintaining the driver's steering operation. There is a problem that it is impossible to awaken.

  SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a driver awakening device that can effectively awaken a driver.

  The present invention relates to an arousal level detecting means for detecting the awakening level of a driver of a vehicle, a steering torque detecting means for detecting a steering torque input to a steering member of the vehicle, and a steering angle detection for detecting a steering angle of the steering member. A decrease in the driver's arousal level is detected by the means, a target steering torque calculating unit that calculates a target steering torque when the steered wheels of the vehicle are steered according to the operation of the steering member, and the arousal level detecting unit Sometimes, the target steering torque calculated by the target steering torque calculating means is added to the target steering torque when the arousal level is lowered by adding the n-th order differential value of the time change of the steering angle detected by the steering angle detecting means. The target assist torque is calculated by subtracting the steering torque detected by the steering torque detecting means from the calculated target steering torque when the arousal level is reduced Calculation means that, on the basis of the target assist torque calculated by said calculating means, characterized in that it comprises a control means for controlling the driving means for turning the steered wheels.

  Thereby, the arousal level of the driver of the vehicle is detected by the arousal level detection means. The steering torque input to the steering member of the vehicle is detected by the steering torque detection means, and the steering angle of the steering member is detected by the steering angle detection means. The target steering torque calculation means calculates the target steering torque when turning the steered wheels of the vehicle according to the operation of the steering member. When a decrease in the driver's arousal level is detected by the arousal level detection unit, the time change of the steering angle detected by the steering angle detection unit is changed to the target steering torque calculated by the target steering torque calculation unit by the calculation unit. The target steering torque when the arousal level decreases is calculated by adding the nth order differential value, and the target assist torque is calculated by subtracting the steering torque detected by the steering torque detecting means from the calculated target steering torque when the arousal level decreases. Calculated. The control means controls the drive means for turning the steered wheels based on the target assist torque calculated by the calculation means.

  For this reason, when the driver operates the steering member in a state where the driver's arousal level is lowered, the steering member is operated by adding the n-th order differential value of the time change of the steering angle to the target steering torque. Immediately after being broken, the target steering torque is calculated when the arousal level is lower than the target steering torque. Then, by subtracting the steering torque from the target steering torque when the arousal level is lowered, the steering member is operated as compared with the target assist torque calculated at the normal time (when the driver's arousal level is not reduced). Immediately after being broken, the target assist torque at the time when the arousal level is reduced is calculated.

  As a result, when the driver operates the steering member, the operation of the steering member is light immediately after the start of the operation, and then the operation becomes heavy (returns to a normal force input amount). As described above, the amount of force necessary for operating the steering member of the driver can be changed, and the driver can be effectively awakened by changing the amount of force required for operating the steering member.

  Moreover, it is preferable that the n-th derivative is a second-order derivative.

  In this case, the second-order differential value of the time change of the steering angle is added to the target steering torque, and immediately after the steering member is operated, the value is larger than the target steering torque. When the vehicle stops (when the steering member is held in a state where the steering member is operated at a predetermined angle), the target steering torque when the arousal level is reduced is smaller than the target steering torque. Then, by subtracting the steering torque from the target steering torque at the time of lowering the arousal level, the value is large immediately after the steering member is operated compared to the target assist torque calculated at the normal time, and the steering member is operated. When the vehicle stops, a target assist torque having a small value is calculated.

  Thereby, when the driver operates the steering member, the operation of the steering member is light immediately after the start of the operation, and then the operation becomes heavier than usual (a force larger than the normal force input amount is required). . As described above, when the operation of the steering member is stopped, the operation of the steering member is increased, that is, the reaction force of the steering member is increased. For this reason, it is possible to prevent the vehicle from deviating from the course assumed by the driver because the operation amount of the steering member becomes larger than the operation amount desired by the driver by reducing the operation of the steering member immediately after the operation. it can.

  Further, it is preferable that the arousal level detection means detects the awakening level based on a driver's closed eye state.

  In this case, it is possible to easily detect a decrease in the driver's arousal level based on the closed state of the driver.

  Further, according to the present invention, when a decrease in the driver's arousal level is detected, the target assist torque is calculated from the target steering torque when the arousal level is decreased by adding the nth-order differential value of the time change of the steering angle to the target steering torque. And the steering driving force of the steered wheels is controlled by the target assist torque.

  Thus, by controlling the steering driving force of the steered wheels by the target assist torque, it becomes possible to change the amount of the driver's force necessary for the operation of the steering member that steers the steered wheels. The driver can be effectively awakened by changing the amount of force required for the operation.

  ADVANTAGE OF THE INVENTION According to this invention, the driver awakening apparatus which can awaken a driver effectively can be provided.

It is a schematic structure figure showing the whole power steering device composition concerning this embodiment. It is a figure which shows the 2nd-order differential value of the time change of a steering angle. It is a figure which shows the change of the steering reaction force at the time of arousal level fall, a steering angle, and a torque. It is a flowchart which shows the flow of a target assist torque calculation process.

  Hereinafter, a preferred embodiment of a power steering apparatus having a driver awakening function to which a driver awakening apparatus according to the present invention is applied will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  First, the overall configuration of the power steering apparatus according to the present embodiment will be described. FIG. 1 is a schematic configuration diagram showing the overall configuration of the power steering apparatus 1. As shown in FIG. 1, in the power steering apparatus 1, a left wheel W <b> 1 and a right wheel W <b> 2 as steering wheels are connected by a steering gear box 20 via a tie rod 10. The steering gear box 20 includes a rack 22, a pinion 24, and the like, and the rack 22 is provided so as to be slidable with respect to the steering gear box 20. A tie rod 10 is connected to both ends of the rack 22, and a steering wheel 32 as a steering member is attached to the pinion 24 via a steering shaft 30.

  A reduction gear 40 is attached to an intermediate portion of the steering shaft 30, and a motor 50 that functions as drive means for turning the left wheel W 1 and the right wheel W 2 is connected to the reduction gear 40. An electronic control unit (hereinafter referred to as “ECU (Electronic Control Unit)”) 60 is connected to the motor 50, and driving is controlled by the ECU 60.

  When the steering wheel 32 is operated by the driver 100, a steering torque is applied to the steering shaft 30. The pinion 24 is rotated by this steering torque, whereby the rack 22 is slid with respect to the steering gear box 20, and the left and right front wheels W1, W2 are steered via the tie rod 10. When the motor 50 is driven, motor torque is applied to the steering shaft 30 via the speed reducer 40. That is, the steering shaft 30 is supplied with both the steering torque generated by the operation of the driver 100 applied to the steering wheel 32 and the motor torque output from the motor 50.

  In addition, a steering torque sensor 61 that functions as a steering torque detection unit that detects the steering torque input to the steering wheel 32 is provided at an intermediate portion of the steering shaft 30. The steering torque sensor 61 outputs a signal corresponding to the magnitude of the steering torque input to the steering wheel 32 by the driver 100 to the ECU 60. Further, a steering angle sensor 62 that functions as a steering angle detection unit that detects the steering angle of the steering wheel 32 is provided at an intermediate portion of the steering shaft 30. The steering angle sensor 62 outputs a signal corresponding to the direction and magnitude of the steering angle input by the driver 100 to the steering wheel 32 to the ECU 60.

  The power steering apparatus 1 also includes an arousal level detection device 70 that functions as an awakening level detection unit that detects the awakening level of the driver 100 of the vehicle. The arousal level detection device 70 includes a camera (not shown) and the like. The eye 101 of the driver 100 is imaged by the camera, and the closed state of the eye 101 is detected by performing image processing and the like. The awakening level detection device 70 detects the awakening level of the driver 100 based on the detected closed eye state of the eye 101. Specifically, for example, when the eye closed state of the eye 101 continues for a predetermined time or more, it is detected that the awakening level of the driver 100 is in a lowered state. When the awakening level detection device 70 detects that the awakening level of the driver 100 is in a lowered state, the awakening level detection device 70 outputs a signal to the ECU 60 that the awakening level of the driver 100 is in a lowered state.

  The ECU 60 includes a target steering torque calculation unit 63, a calculation unit 64, and a control unit 65.

  The target steering torque calculation unit 63 functions as target steering torque calculation means for calculating a target steering torque when the left wheel W1 and the right wheel W2 of the vehicle are steered according to the operation of the steering wheel 32. Therefore, the target steering torque calculation unit 63 turns the left wheel W1 and the right wheel W2 based on the steering torque detected by the steering torque sensor 61, the steering angle detected by the steering angle sensor 62, and the like. The target steering torque is calculated. The target steering torque is a value obtained by adding the steering torque by the operation of the driver 100 applied to the steering wheel 32 and the motor torque applied by the motor 50. The target steering torque calculated by the target steering torque calculation unit 63 can be calculated using an existing technique.

  The calculation unit 64 functions as a calculation unit that calculates a target assist torque that is a target when the control unit 65 controls the motor 50. Therefore, the calculation unit 64 is detected by the steering torque sensor 61 from the target steering torque calculated by the target steering torque calculation unit 63 when the decrease in the driver's arousal level is not detected by the arousal level detection device 70. The target assist torque at the normal time is calculated by subtracting the steering torque.

  On the other hand, when a decrease in the driver's arousal level is detected by the arousal level detection device 70, the calculation unit 64 first detects the target steering torque calculated by the target steering torque calculation unit 63 by the steering angle sensor 62. The target steering torque at the time when the arousal level is lowered is calculated by adding the second-order differential value of the steering angle with time.

  Here, the second-order differential value of the time change of the steering angle will be described with reference to FIGS. 2 (a) to 2 (c). As shown in FIG. 2A, when the vehicle driver 100 starts operating the steering wheel 32 at time t1, the steering angle of the steering wheel 32 gradually increases after time t1. It is assumed that the steering angle of the position of the steering wheel 32 when the vehicle is traveling straight is zero. After time t2 when the steering wheel 32 is operated to a desired angle by the driver 100, the steering angle of the steering wheel 32 is maintained in a constant state. Thus, when the steering wheel 32 is operated by the driver 100, the steering angle changes with time as shown in FIG. The value shown in FIG. 2B is obtained by first-order differentiation of the time change of the steering angle shown in FIG. Further, the result of the first-order differentiation of the time change of the steering angle shown in FIG. 2B is further differentiated by the first order, that is, the time change of the steering angle shown in FIG. The value shown in 2 (c) is obtained. That is, as shown in FIG. 2C, the second-order differentiation of the time change of the steering angle is performed immediately after the operation of the steering wheel 32 (time t1), as shown in FIG. When the value becomes a positive value and the operation of the steering wheel 32 stops (time t2), the second-order differential value of the time change of the steering angle becomes a negative value.

  Therefore, immediately after the operation of the steering wheel 32 is performed, a positive value of the second-order differential value of the time change of the steering angle is added to the target steering torque, thereby reducing the arousal level that is larger than the target steering torque. Hour target steering torque is calculated. When the operation of the steering wheel 32 stops (when the steering wheel 32 is held at a desired angle), the target steering torque has a negative second-order differential value of the steering angle over time. By adding the values, the target steering torque at the time of awakening reduction that is smaller than the target steering torque is calculated.

  After calculating the target steering torque when the wakefulness level is reduced, the calculation unit 64 subtracts the steering torque detected by the steering torque sensor 61 from the calculated target steering torque when the wakefulness level is reduced to thereby reduce the target assist torque when the wakefulness level is reduced. Is calculated.

  As a result, compared with the target assist torque calculated in the normal time (when the decrease in the driver's arousal level is not detected by the arousal level detection device 70), the value is immediately after the steering wheel 32 is operated. When the operation of the steering wheel 32 is large, the target assist torque when the arousal level is low is calculated.

  The control unit 65 functions as a control unit that controls the motor 50 that steers the left wheel W1 and the right wheel W2 based on the target assist torque calculated by the calculation unit 64. For this reason, the control unit 65 controls the motor 50 so that the motor torque output from the motor 50 becomes the target assist torque calculated by the calculation unit 64.

  In particular, when a decrease in the driver's arousal level is detected by the arousal level detection device 70, the control unit 65 has a value immediately after the steering wheel 32 is steered, compared with the target assist torque at the normal time. When the operation of the steering wheel 32 stops, the motor torque output by the motor 50 is controlled based on the target assist torque when the wakefulness level is reduced. For this reason, the motor torque output from the motor 50 is large immediately after the steering wheel 32 is steered, and is small when the operation of the steering wheel 32 is stopped.

  That is, as shown in FIG. 3A, the steering reaction force when the driver 100 operates the steering wheel 32 decreases for a short time at time t1 immediately after the steering wheel 32 is steered. It increases only for a short time at time t2 when the operation of 32 stops. For this reason, when the driver 100 operates the steering wheel 32, the operation of the steering wheel 32 is light immediately after the start of the operation, and then the operation becomes heavier than usual (a force larger than the normal force input amount is necessary). Becomes).

  Further, as shown in FIG. 3B, the change in the steering angle when it is detected that the awakening level of the driver 100 is in a lowered state is that the steering wheel 32 is steered compared to the normal time. Immediately after, the operation of the steering wheel 32 becomes light and the rate of change of the steering angle increases. When the operation of the steering wheel 32 stops, the operation of the steering wheel 32 becomes heavy and the rate of change of the steering angle becomes gentle. Further, as shown in FIG. 3C, the torque required for operation of the steering wheel 32 when it is detected that the awakening level of the driver 100 is in a lowered state is higher than that in the normal time. Immediately after the steering is performed, it is small, and it is large when the operation of the steering wheel 32 is stopped. Thus, when the driver's arousal level is reduced, the amount of force required to operate the steering wheel 32 changes.

  As described above, in this embodiment, the driver torque alert device according to the present invention is configured by the steering torque sensor 61, the steering angle sensor 62, the target steering torque calculator 63, the calculator 64, the controller 65, and the alertness detector 70. In addition, the amount of force required to operate the steering wheel 32 when the driver's arousal level is reduced can be changed by the driver awakening device.

  Next, the flow of target assist torque calculation processing when the arousal level is reduced will be described. FIG. 4 is a flowchart showing the flow of target assist torque calculation processing. This process is started when an ignition switch for starting the vehicle is turned on, and is ended when the ignition switch is turned off. First, the wakefulness detection device 70 detects the wakefulness of the driver 100 based on the closed state of the eye 101 of the driver 100 (step S101). When it is detected that the awakening level of the driver 100 is in a lowered state (step S101: YES), the calculation unit 64 calculates a target assist torque when the awakening level is lowered (step S102).

  Specifically, as described above, the calculation unit 64 first adds the second-order differential value of the time change of the steering angle detected by the steering angle sensor 62 to the target steering torque calculated by the target steering torque calculation unit 63. Is added to calculate the target steering torque when the arousal level is reduced. And the calculating part 64 calculates the target assist torque at the time of wakefulness fall by subtracting the steering torque detected by the steering torque sensor 61 from the calculated target steering torque at the time of wakefulness fall.

  The control unit 65 controls the motor 50 so that the motor torque output from the motor 50 becomes the target assist torque based on the target assist torque when the arousal level is reduced or the normal target assist torque calculated in step S104 described later. Is controlled (step S103).

  On the other hand, when it is detected in step S101 that the awakening level of the driver 100 is not in a lowered state (step S101: NO), the calculation unit 64 calculates the target steering torque calculated by the target steering torque calculation unit 63 as described above. Then, the target assist torque at the normal time is calculated by subtracting the steering torque detected by the steering torque sensor 61 (step S104).

  As described above, it is necessary for the operation of the steering wheel 32 by changing the target assist torque of the motor 50 based on whether or not the awakening level of the driver 100 is detected to be in a lowered state by the awakening level detection device 70. The amount of force can be changed.

  Then, the effect | action and effect of the power steering apparatus 1 concerning this embodiment are demonstrated. According to the power steering device 1 of the present embodiment, the awakening level of the driver 100 of the vehicle is detected by the awakening level detection device 70. The steering torque input to the steering wheel 32 of the vehicle is detected by the steering torque sensor 61, and the steering angle of the steering wheel 32 is detected by the steering angle sensor 62. The target steering torque calculation unit 63 calculates the target steering torque for turning the steered wheels (left wheel W1, right wheel W2) of the vehicle according to the operation of the steering wheel 32. The steering angle detected by the steering angle sensor 62 to the target steering torque calculated by the target steering torque calculation unit 63 by the calculation unit 64 when the decrease in the arousal level of the driver 100 is detected by the arousal level detection device 70. By subtracting the steering torque detected by the steering torque sensor 61 from the calculated target steering torque at the time of wakefulness reduction, the second-order differential value of the time change of is calculated. A target assist torque is calculated. The control unit 65 controls the motor 50 that steers the steered wheels (left wheel W1, right wheel W2) based on the target assist torque calculated by the computing unit 64.

  For this reason, when the driver 100 operates the steering wheel 32 in a state where the awakening level of the driver 100 is lowered, the second-order differential value of the time change of the steering angle is added to the target steering torque, thereby the steering wheel 32. Immediately after the operation is performed, the value is larger than the target steering torque, and when the operation of the steering wheel 32 stops (when the steering wheel 32 is held at a predetermined angle), the target steering torque is reached. The target steering torque is calculated when the arousal level is lower than this value. Then, by subtracting the steering torque from the target steering torque at the time of lowering the arousal level, the value is larger immediately after the steering wheel 32 is operated compared to the target assist torque calculated at the normal time. When the operation stops, a target assist torque having a small value is calculated.

  For this reason, when the driver 100 operates the steering wheel 32, the operation of the steering wheel 32 is light immediately after the start of the operation, and then the operation becomes heavier than usual (a force larger than the normal force input amount is necessary). Becomes). As described above, the amount of force necessary for operating the steering wheel 32 of the driver 100 can be changed, and the driver 100 is effectively awakened by changing the amount of force required for operating the steering wheel 32. be able to.

  Further, when the operation of the steering wheel 32 is stopped, the operation of the steering wheel 32 is increased, that is, the reaction force of the steering wheel 32 is increased. For this reason, the amount of operation of the steering wheel 32 becomes larger than the amount of operation desired by the driver 100 by reducing the operation of the steering wheel 32 immediately after the operation, and the vehicle deviates from the course assumed by the driver 100. Can be prevented.

  Further, the arousal level detection device 70 detects the arousal level based on the closed state of the eye 101 of the driver 100, thereby facilitating the detection process of the arousal level.

  The present invention is not limited to the above embodiment. For example, the second-order differential value of the time change of the steering angle is added to the target steering torque, but other differential ranks may be used. For example, you may add the 1st-order differential value of the time change of the steering angle shown in FIG.2 (b) to a target steering torque. In this case, when the driver 100 operates the steering wheel 32, the operation of the steering wheel 32 is light immediately after the start of the operation, and then the operation becomes heavy (returns to a normal force input amount). Accordingly, even in this case, it is possible to change the amount of force necessary for the operation of the steering wheel 32 of the driver 100. By changing the amount of force necessary for the operation of the steering wheel 32, the driver 100 can be changed. Can be awakened effectively.

  Moreover, although the arousal level detection apparatus 70 shall detect the arousal level of the driver 100 based on the closed eye state of the eye 101 of the driver 100, it can also detect the arousal level by other methods.

  DESCRIPTION OF SYMBOLS 1 ... Power steering apparatus, 32 ... Steering wheel, 50 ... Motor, 61 ... Steering torque sensor, 62 ... Steering angle sensor, 63 ... Target steering torque calculation part, 64 ... Calculation part, 65 ... Control part.

Claims (4)

Wakefulness detection means for detecting the wakefulness of the driver of the vehicle;
Steering torque detection means for detecting steering torque input to a steering member of the vehicle;
Steering angle detecting means for detecting a steering angle of the steering member;
Target steering torque calculating means for calculating a target steering torque when turning the steered wheels of the vehicle according to the operation of the steering member;
When a decrease in the driver's arousal level is detected by the arousal level detection unit, the time change of the steering angle detected by the steering angle detection unit is added to the target steering torque calculated by the target steering torque calculation unit. The target steering torque is calculated by adding the n-th order differential value and subtracting the steering torque detected by the steering torque detecting means from the calculated target steering torque when the arousal level is reduced. Computing means for calculating torque;
Control means for controlling drive means for turning the steered wheels based on the target assist torque calculated by the calculation means;
A driver awakening device comprising:   The driver awakening device according to claim 1, wherein the n-th order differentiation is a second-order differentiation.   3. The driver awakening device according to claim 1, wherein the awakening level detection unit detects the awakening level based on a closed eye state of the driver.   When a decrease in the driver's arousal level is detected, a target assist torque is calculated from the target steering torque calculated by adding the n-th order differential value of the change in steering angle to the target steering torque, and the target assist torque is calculated. A driver awakening device that controls a turning driving force of a steered wheel by an assist torque.

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