JP4778818B2 - Vehicle operation support device - Google Patents

Description

  The present invention relates to a vehicle operation support device that supports a collision avoidance operation performed by a driver to avoid a collision with an obstacle when the vehicle is traveling.

When a driver performs a steering operation during automatic braking of the vehicle and an obstacle can be avoided by turning control by the vehicle behavior control means, if there is an avoidance space ahead of the vehicle, the vehicle should avoid the obstacle. If there is no avoidance space in front of the vehicle, control to increase the stability of the vehicle by giving up avoidance of obstacles, and avoiding collision by automatic braking and steering operation Patent Document 1 below discloses a technique that effectively achieves collision avoidance.
JP 11-348799 A

  By the way, when the vehicle is understeered and the driver increases the steering wheel in an attempt to turn the vehicle further, the steering operation of the driver is assisted by the steering actuator. However, if the driver performs a large and abrupt steering operation to avoid a collision with an obstacle when the vehicle is understeered, the vehicle is understeered and excessive assist is performed, resulting in an excessive steering angle. The return operation after avoiding an obstacle may become difficult.

  The present invention has been made in view of the above circumstances, and when a steering operation is performed for avoiding a collision, it is possible to prevent a steering angle from becoming excessive due to excessive assist and facilitate a return operation. Objective.

In order to achieve the above object, according to the first aspect of the present invention, in a vehicle operation support device that supports a collision avoidance operation performed by a driver to avoid a collision with an obstacle when the vehicle is running, Reference yaw rate calculation means for calculating a reference yaw rate, collision avoidance operation determination means for determining a collision avoidance operation by a driver, obstacle detection means for detecting an obstacle with which the host vehicle may collide, and collision avoidance operation determination When the means determines the collision avoidance operation by the driver, the avoidance exercise amount calculation means for calculating the avoidance exercise amount necessary for avoiding the obstacle detected by the obstacle detection means, and the reference yaw rate calculated by the reference yaw rate calculation means The normative yaw rate correcting means for correcting with the avoiding momentum calculated by the avoiding momentum calculating means, and the deviation between the corrected normative yaw rate and the actual yaw rate. Target assist current calculation means for calculating a target assist current to be supplied to the steering actuator based on the above, an understeer determination means for determining an understeer state of the vehicle, an understeer determination means for determining an understeer state of the vehicle, and a collision avoidance operation determination When a collision avoidance operation by the driver is determined by the means, a reaction force current that reduces the target assist current is calculated , the understeer state of the vehicle is determined by the understeer determination means, and the collision avoidance by the driver is determined by the collision avoidance operation determination means There is proposed a vehicle operation support device including a reaction force current calculation unit that does not calculate a reaction force current that decreases a target assist current when an operation is not determined .

According to the second aspect of the present invention, in the vehicle operation support device that supports the collision avoidance operation performed by the driver to avoid the collision with the obstacle when the vehicle is traveling, the collision that determines the collision avoidance operation by the driver. The avoidance operation determination means, the obstacle detection means for detecting an obstacle with which the host vehicle may collide, and the obstacle detection means detected when the collision avoidance operation determination means determined the collision avoidance operation by the driver. Avoidance exercise amount calculating means for calculating an avoidance exercise amount necessary for avoiding the obstacle, target assist current calculation means for calculating a target assist current to be supplied to the steering actuator based on the avoidance exercise amount calculated by the avoidance exercise amount calculation means, Understeer determination means for determining an understeer state of the vehicle and understeer of the vehicle by the understeer determination means A state is judged, and when the collision avoidance operation by the driver is determined by the collision avoidance operation determining section calculates a reaction force current to reduce the target assist current, under-steering state of the vehicle is determined by the understeer judging means, And a vehicle operation support device, comprising: a reaction force current calculation unit that does not calculate a reaction force current that decreases the target assist current when the collision avoidance operation by the driver is not determined by the collision avoidance operation determination unit. Is done.

  According to the configuration of claim 1, when the driver performs the collision avoidance operation with the obstacle, the avoidance momentum necessary for the vehicle to avoid the obstacle is calculated, and the reference yaw rate corrected by the avoidance momentum and the actual yaw rate are calculated. A target assist current to be supplied to the steering actuator is calculated based on the deviation from the yaw rate, and this target assist current is supplied to the steering actuator to assist the driver's collision avoidance operation. When the vehicle's understeer condition is determined and the collision avoidance operation by the driver is determined, the target assist current is reduced by the reaction force current, so that the steering angle is prevented from becoming excessive due to excessive assist, and obstacles The return operation after avoiding this can be facilitated.

  According to the configuration of claim 2, when the driver performs the collision avoidance operation with the obstacle, the avoidance momentum necessary for the own vehicle to avoid the obstacle is calculated and supplied to the steering actuator based on the avoidance momentum. A target assist current is calculated, and this target assist current is supplied to the steering actuator to assist the driver's collision avoidance operation. When the vehicle's understeer condition is determined and the collision avoidance operation by the driver is determined, the target assist current is reduced by the reaction force current, so that the steering angle is prevented from becoming excessive due to excessive assist, and obstacles The return operation after avoiding this can be facilitated.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 6 show a first embodiment of the present invention. FIG. 1 is a diagram showing the overall configuration of an automobile equipped with an operation support device, FIG. 2 is a diagram showing the configuration of a steering device, and FIG. 4 is a block diagram of the control system of the support device, FIG. 4 is an explanatory diagram of a target lateral movement distance, FIG. 5 is a diagram illustrating a determination method of oversteer, understeer, countersteer and neutral steer, and FIG. 6 is a reaction force current from yaw rate deviation. It is a figure which shows the map to search.

  As shown in FIGS. 1 and 2, the four-wheeled vehicle equipped with the operation support device of the present embodiment has left and right front wheels WFL, WFR as drive wheels to which the driving force of the engine E is transmitted via a transmission T. The left and right rear wheels WRL and WRR are driven wheels that rotate as the vehicle travels.

  The rotation of the steering wheel 11 is transmitted to the rack 15 via the steering shaft 12, the connecting shaft 13 and the pinion 14, and the reciprocation of the rack 15 is transmitted to the left and right front wheels WFL, WFR via the left and right tie rods 16, 16. The The power steering device 17 provided in the steering device includes a drive gear 19 provided on the output shaft of the steering actuator 18, a driven gear 20 that meshes with the drive gear 19, a screw shaft 21 that is integrated with the driven gear 20, And a nut 22 engaged with the screw shaft 21 and connected to the rack 15. Therefore, when the steering actuator 18 is driven, the driving force is transmitted to the left and right front wheels WFL, WFR via the drive gear 19, the driven gear 20, the screw shaft 21, the nut 22, the rack 15, and the left and right tie rods 16,16. be able to.

  The electronic control unit U emits electromagnetic waves such as millimeter waves toward the front of the vehicle body, and based on the reflected waves, the relative distance between the obstacle and the vehicle, the relative speed between the obstacle and the vehicle, A radar device Sa that detects the offset distance from the host vehicle and the lateral width of the obstacle, a wheel speed sensor Sb that detects the rotational speeds of the front wheels WFL, WFR and the rear wheels WRL, WRR, and a steering angle δ of the steering wheel 11 A steering angle sensor Sc to detect, a yaw rate sensor Se to detect the actual yaw rate γ of the vehicle, and a lateral acceleration sensor Sf to detect the lateral acceleration G of the vehicle are connected.

  Note that a laser radar can be employed in place of the radar device Sa composed of a millimeter wave radar.

  The electronic control unit U controls the operation of the steering actuator 18 based on signals from the radar device Sa and signals from the wheel speed sensor Sb..., The steering angle sensor Sc, the yaw rate sensor Se, and the lateral acceleration sensor Sf.

  As shown in FIG. 3, the electronic control unit U includes a reference yaw rate calculation means M1, a collision avoidance operation determination means M2, an obstacle detection means M3, an avoidance exercise amount calculation means M4, a reference yaw rate correction means M5, a target Assist steering angle calculation means M6, target assist current calculation means M7, understeer determination means M8, reaction force current calculation means M9, and target current calculation means M10.

  Next, the normal operation in which the driver does not perform the obstacle avoidance operation will be described.

  The reference yaw rate calculation means M1 calculates a reference yaw rate γt based on the steering angle δ detected by the steering angle sensor Sc and the vehicle speed V calculated from the output of the wheel speed sensor Sb. The target assist steering angle calculation means M6 calculates a target assist steering angle based on a deviation (yaw rate deviation Δγ) between the actual yaw rate γ detected by the yaw rate sensor Se and the reference yaw rate γt. The target assist steering angle corresponds to the steering angle added by the power steering device 17 to the steering angle δ at which the driver actually operates the steering wheel 11 in order to eliminate the oversteer state and the understeer state of the vehicle. The target assist current calculation means M7 converts the target assist steering angle calculated by the target assist steering angle calculation means M6 into a target assist current that is supplied to the steering actuator 18.

  The target current calculating means M10 calculates a target current to be supplied to the steering actuator 18 based on, for example, the steering torque detected by the steering torque sensor and the vehicle speed V calculated from the output of the wheel speed sensor Sb. Then, the steering actuator 18 is driven based on a current value obtained by adding the target assist current converted by the target assist current calculation means M7 to the target current calculated by the target current calculation means M10. Thus, when the vehicle is in an oversteer tendency, the steering wheel 11 is lightened in the direction of turning back, and when the vehicle is in an understeer tendency, the ease of turning the steering wheel 11 is suppressed to assist the driver's steering operation. it can.

  Next, the operation at the time of avoidance in which the driver performs an obstacle avoidance operation will be described.

  The collision avoidance operation determination means M2 determines whether or not the driver has performed an operation for avoiding the obstacle O based on the steering angle δ of the steering wheel 11 detected by the steering angle sensor Sc. Specifically, the steering angular velocity dδ / dt obtained by time differentiation of the steering angle δ is equal to or higher than a predetermined value (for example, 0.85 rad / sec), or the steering angle δ output from the steering angle sensor Sc is a predetermined value (for example, 0.3 rad). At this time, it is determined that the driver has performed an operation for avoiding the obstacle.

  As shown in FIG. 4, in addition to the relative speed and relative distance between the obstacle O and the own vehicle, the radar device Sa has a lateral width w of the obstacle O and a deviation of the center of the obstacle O from the center line of the own vehicle. That is, the offset distance Do is detected.

The obstacle detection means M3 determines the obstacle O on the predicted course of the host vehicle based on the detection result by the radar device Sa. When the collision avoidance operation determination means M2 determines the avoidance operation by the driver, the avoidance momentum calculation means M4 automatically calculates the avoidance exercise amount calculation means M4 based on the width W of the obstacle O, the known width W of the vehicle, and the predetermined margin α. The avoidance momentum (target lateral movement distance) Dt necessary for the vehicle to avoid the obstacle O is
Dt = (w / 2) + (W / 2) + α-Do
Calculated by

  It is most difficult to avoid a collision between the own vehicle and the obstacle O when the center of the obstacle O is on the center line of the own vehicle, that is, when the obstacle O is directly in front of the own vehicle. Even in this case, if the vehicle moves in the lateral direction by the target lateral movement distance Dt, it can pass through the obstacle O with a margin corresponding to the margin α.

  The normative yaw rate correcting means M5 corrects the normative yaw rate γt calculated by the normative yaw rate calculating means M1 by the avoiding exercise amount Dt calculated by the avoiding exercise amount calculating means M4. As a result, the standard yaw rate γt calculated from the steering angle δ and the vehicle speed V is corrected so as to increase as it becomes difficult for the vehicle to avoid the obstacle O. Thus, when the driver performs a steering operation for avoiding a collision with the obstacle O, the steering operation can be assisted by the power steering device 17 to effectively avoid the collision.

  The understeer determination means M8 determines that the vehicle is in an understeer state based on the reference yaw rate γt calculated by the reference yaw rate calculation means M1, the yaw rate deviation Δγ, and the lateral acceleration G detected by the lateral acceleration sensor Sf.

  FIG. 5 shows changes in the yaw rate γ (see the alternate long and short dash line), the normative yaw rate γt (see the solid line), the yaw rate deviation Δγ (see the broken line), and the lateral acceleration G (see the alternate long and two short dashes line) when the vehicle changes lanes. It is. Whether the vehicle is oversteering, understeering, countersteering, or neutral steering is determined by the signs of the reference yaw rate γt, yaw rate deviation Δγ, and lateral acceleration G.

  That is, the vehicle is oversteer in the regions (b) and (e) where the yaw rate deviation Δγ and the standard yaw rate γt are opposite signs, and the vehicle is neutral steer in the region (g) where the yaw rate deviation Δγ is almost zero. The yaw rate deviation Δγ and the reference yaw rate γt have the same sign, and the lateral acceleration G also has the same sign in the regions (a) and (d). The vehicle is understeer, and the yaw rate deviation Δγ and the reference yaw rate γt have the same sign. The vehicle is counter-steered in the regions (c) and (f) where the lateral acceleration G is opposite in sign.

  The reaction force current calculation means M9 calculates a reaction force current based on the yaw rate deviation Δγ when the understeer determination means M8 determines the understeer state and the collision avoidance operation determination means M2 determines the collision avoidance operation of the driver. As shown in FIG. 6, the reaction force current rises at a predetermined rate from the moment when the yaw rate deviation Δγ exceeds a predetermined value (for example, 0.5 rad / sec), and is kept constant at a predetermined current value (for example, 40 A). . The reaction force current calculated in this way is subtracted from the target assist current calculated by the target assist current calculation means M7.

  Then, the steering actuator 18 is driven based on the current value obtained by adding the target assist current corrected with the reaction force current to the target current calculated by the target current calculation means M10. Since the force current decreases, the steering reaction force against the driver's steering operation increases.

  When the vehicle is understeered, the driver tends to increase the steering wheel 11 in an attempt to generate his intended yaw rate γ. At this time, the driver's steering is performed by the target assist current that increases as the yaw rate deviation Δγ increases. Operation is assisted. In particular, when the vehicle is understeering and the driver performs a large and abrupt steering operation to avoid a collision with the obstacle O, the driver's steering operation is assisted by the increased target assist current. In this case, the steering angle becomes excessive, and the return operation after the collision avoidance may be difficult.

  However, according to the present embodiment, when the driver's collision avoidance operation is determined when the vehicle is in an understeer state, the target assist current decreases by the amount of the reaction force current calculated by the reaction force current calculation means M9. Further, it is possible to avoid a situation in which the steering reaction force of the steering wheel 11 is increased and the turning increase is suppressed more than usual, and an excessive steering angle is generated and the return operation becomes difficult.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  In the first embodiment described above, as shown in FIG. 3, when the collision avoidance operation determination means M2 determines an avoidance operation by the driver, the avoidance momentum calculation means M4 avoids the obstacle O detected by the obstacle detection means M3. The avoidance exercise amount Dt necessary for the calculation is calculated, and the reference yaw rate correction means M5 corrects the reference yaw rate γt calculated by the reference yaw rate calculation means M1 with the avoidance exercise amount Dt. The target assist steering angle calculation means M6 calculates a target assist steering angle based on the deviation between the actual yaw rate γ and the reference yaw rate γt, and the target assist current calculation means M7 supplies the target assist steering angle to the steering actuator 18. Convert to assist current.

  On the other hand, as shown in FIG. 7, the second embodiment does not include the normative yaw rate correction means M5 and the target assist steering angle calculation means M6 of the first embodiment, and the avoidance exercise quantity calculated by the avoidance exercise quantity calculation means M4. Based on Dt, the target assist current calculation means M7 directly calculates the target assist current.

  In the first embodiment, the yaw rate deviation Δγ input to the understeer determination means M8 and the reaction force current calculation means M9 is a deviation between the reference yaw rate γt corrected by the reference yaw rate correction means M5 and the actual yaw rate γ. In the second embodiment, since the normative yaw rate correcting means M5 is not provided, the deviation between the uncorrected normative yaw rate γt and the actual yaw rate γ is input to the understeer determining means M8 and the reaction force current calculating means M9.

  Similar to the first embodiment, when the collision avoidance operation of the driver is determined when the vehicle is understeered, the target assist current is decreased by the amount of the reaction force current calculated by the reaction force current calculation means M9. It is.

  Thus, according to the second embodiment, while achieving the same effect as the first embodiment described above, the reference yaw rate correcting means M5 and the target assist steering angle calculating means M6 are abolished and the structure of the control system is reduced. It can be simplified.

  Although the embodiments of the present invention have been described above, various design changes can be made without departing from the scope of the present invention.

  For example, in the embodiment, the collision with the obstacle O is avoided at the front wheel steering angle generated by the power steering device 17, but it is generated by giving a difference between the braking force of the left wheel and the braking force of the right wheel. It is also possible to avoid collision with the obstacle O with the yaw moment.

The figure which shows the whole structure of the motor vehicle carrying the operation assistance apparatus which concerns on 1st Example. Diagram showing the configuration of the steering device Block diagram of the control system of the operation support device Illustration of target lateral movement distance The figure explaining the judgment method of oversteer, understeer, counter steer, and neutral steer The figure which shows the map which searches reaction force current from yaw rate deviation Block diagram of the control system of the operation support apparatus according to the second embodiment

M1 reference yaw rate calculation means M2 collision avoidance operation determination means M3 obstacle detection means M4 avoidance exercise amount calculation means M5 reference yaw rate correction means M7 target assist current calculation means M8 understeer determination means M9 reaction force current calculation means O obstacle γ actual yaw rate γt reference Yaw rate 18 Steering actuator

Claims (2)

In a vehicle operation support device that supports a collision avoidance operation performed by a driver to avoid a collision with an obstacle (O) when the vehicle is running,
A reference yaw rate calculating means (M1) for calculating a reference yaw rate (γt) of the vehicle;
A collision avoidance operation determination means (M2) for determining a collision avoidance operation by the driver;
An obstacle detection means (M3) for detecting an obstacle (O) with which the host vehicle may collide,
When the collision avoidance operation determination means (M2) determines the collision avoidance operation by the driver, the avoidance exercise amount calculation calculates the avoidance exercise amount necessary to avoid the obstacle (O) detected by the obstacle detection means (M3). Means (M4);
A normative yaw rate correcting means (M5) for correcting the normative yaw rate (γt) calculated by the normative yaw rate calculating means (M1) with the avoiding exercise amount calculated by the avoiding exercise amount calculating means (M4);
Target assist current calculation means (M7) for calculating a target assist current to be supplied to the steering actuator (18) based on the deviation between the corrected standard yaw rate (γt) and the actual yaw rate (γ);
Understeer determination means (M8) for determining an understeer state of the vehicle;
When the understeer state of the vehicle is determined by the understeer determination means (M8) and the collision avoidance operation by the driver is determined by the collision avoidance operation determination means (M2), a reaction force current for reducing the target assist current is calculated . Reaction force that does not calculate a reaction force current that reduces the target assist current when the understeer state of the vehicle is determined by the understeer determination means (M8) and the collision avoidance operation by the driver is not determined by the collision avoidance operation determination means (M2) Current calculating means (M9);
A vehicle operation support device comprising: In a vehicle operation support device that supports a collision avoidance operation performed by a driver to avoid a collision with an obstacle (O) when the vehicle is running,
A collision avoidance operation determination means (M2) for determining a collision avoidance operation by the driver;
An obstacle detection means (M3) for detecting an obstacle (O) with which the host vehicle may collide,
When the collision avoidance operation determination means (M2) determines the collision avoidance operation by the driver, the avoidance exercise amount calculation calculates the avoidance exercise amount necessary to avoid the obstacle (O) detected by the obstacle detection means (M3). Means (M4);
Target assist current calculation means (M7) for calculating a target assist current to be supplied to the steering actuator (18) based on the avoidance exercise quantity calculated by the avoidance exercise quantity calculation means (M4);
Understeer determination means (M8) for determining an understeer state of the vehicle;
When the understeer state of the vehicle is determined by the understeer determination means (M8) and the collision avoidance operation by the driver is determined by the collision avoidance operation determination means (M2), a reaction force current for reducing the target assist current is calculated . Reaction force that does not calculate a reaction force current that reduces the target assist current when the understeer state of the vehicle is determined by the understeer determination means (M8) and the collision avoidance operation by the driver is not determined by the collision avoidance operation determination means (M2) Current calculating means (M9);
A vehicle operation support device comprising:

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