JP2008049932A - Contact evasion support device of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely evade contact, without imparting a sense of incongruity to a driver, when supporting contact evasion with an obstacle by automatic braking. <P>SOLUTION: When an ultrasonic sensor Sa detects a distance of the obstacle in front of a vehicle, a target speed calculating means M1 calculates a target speed of the vehicle in response to the distance of its obstacle. Since a braking force control means M6 controls braking force based on its target speed, the contact with the obstacle can be surely evaded by supporting spontaneous contact evading operation of the driver by reducing a vehicle speed by the automatic braking. At this time, since the target speed calculated by the target speed calculating means M1 is corrected in response to any of a steering angle δ, a steering angle speed dδ/dt and accelerator opening θAP of a steering wheel by operation of the driver, interference with the spontaneous contact evading operation of the driver when performing excessive automatic braking, is prevented, and the sense of incongruity of the driver can be eliminated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle contact avoidance assist device that generates a braking force that assists in avoiding contact with an obstacle according to the state of the obstacle ahead of the vehicle.

  When a plurality of long-distance detection sensors and a plurality of short-distance detection sensors are arranged around the vehicle and each of the sensors detects that an obstacle such as another vehicle has entered a preset danger detection area, A device that gives a warning and prompts a spontaneous contact avoidance operation is known from Patent Document 1 below.

In addition, by detecting the distance of obstacles around the vehicle with the surrounding monitoring means and automatically braking the vehicle based on the braking request value calculated according to this distance, the distance to the obstacle can be any. However, it is known from Patent Document 2 below that the vehicle is automatically stopped with a good feeling for the driver.
JP 2003-329773 A JP 2004-50925 A

  By the way, what is described in Patent Document 1 does not perform automatic braking only by issuing a warning to the driver when there is a possibility that the vehicle is in contact with an obstacle. There was a problem of not being able to support enough.

  In addition, the above-described patent document 2 does not consider the case where the driver voluntarily performs steering operation to avoid contact or the case where the driver voluntarily accelerates. There was a possibility that the driver would feel uncomfortable by braking.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to enable reliable contact avoidance without giving a driver a sense of incongruity when assisting contact avoidance with an obstacle by automatic braking. .

  In order to achieve the above object, according to the first aspect of the present invention, a vehicle contact avoidance support that generates a braking force that supports contact avoidance with an obstacle according to the state of the obstacle ahead of the vehicle. A front obstacle sensor for detecting a distance of an obstacle ahead of the vehicle, a target speed calculating means for calculating a target speed of the vehicle according to the distance of the obstacle detected by the front obstacle sensor, and a driver A target speed correcting means for correcting the target speed in accordance with the operation state of the vehicle, and a braking force control means for controlling the braking force based on the target speed corrected by the target speed correcting means. A vehicle contact avoidance support device is proposed.

  According to the invention described in claim 2, in addition to the configuration of claim 1, the operation state of the vehicle by the driver is any one of a steering angle, a steering angular velocity, and an accelerator opening. A vehicle contact avoidance support device is proposed.

  According to the invention described in claim 3, in addition to the configuration of claim 1 or claim 2, hydraulic pressure conversion means for converting the deviation between the target speed and the actual vehicle speed into brake hydraulic pressure, and the driver There is proposed a vehicle contact avoidance assisting device comprising hydraulic pressure change amount limiting means for limiting the change amount of the brake hydraulic pressure in accordance with the brake operation.

  According to a fourth aspect of the invention, in addition to the configuration of the third aspect, the hydraulic pressure change amount limiting means delays the rise of the brake hydraulic pressure when the driver is operating the brake. Thus, a vehicle contact avoidance assisting device is proposed, characterized in that the vehicle speeds up when the driver does not perform a brake operation, and the brake fluid pressure rises faster and falls later.

  According to the invention described in claim 5, in addition to the configuration of any one of claims 1 to 4, a side obstacle sensor for detecting an obstacle on the side of the vehicle, and a side obstacle A target fluid pressure for calculating a target brake fluid pressure to be output to the braking force control device according to the distance between the obstacles detected by the side obstacle sensor and the side obstacles detected by the side obstacle sensor; A vehicle contact avoidance assisting device is proposed in which the detection region setting unit moves the rear end of the detection region to the front side of the vehicle as the steering angle becomes smaller.

  The ultrasonic sensor Sa of the embodiment corresponds to the forward obstacle sensor of the present invention, the television camera Sb of the embodiment corresponds to the side obstacle sensor of the present invention, and the first target speed of the embodiment. The addition amount calculation means 21, the second target speed addition amount calculation means 24, and the third target speed addition amount calculation means 25 correspond to the target speed correction means of the present invention.

  According to the configuration of the first aspect, when the front obstacle sensor detects the distance of the obstacle ahead of the vehicle, the target speed calculation means calculates the target speed of the vehicle according to the distance of the obstacle, and sets the target speed to the target speed. Based on this, the braking force control means controls the braking force, so that the driver's spontaneous contact avoidance operation can be supported by decelerating the vehicle speed by automatic braking, so that contact with an obstacle can be reliably avoided. At this time, since the target speed correction means corrects the target speed according to the operation state of the vehicle by the driver, it is possible to prevent excessive automatic braking from being performed and interfere with the driver's spontaneous contact avoidance operation. The discomfort of the person can be eliminated.

  According to the second aspect of the present invention, the target speed is corrected according to any one of the steering angle, the steering angular speed, and the accelerator opening, so that the target speed that accurately reflects the operation state of the vehicle by the driver can be obtained. it can.

  According to the third aspect of the present invention, the hydraulic pressure conversion means converts the deviation between the target speed and the actual vehicle speed into the brake hydraulic pressure, and the hydraulic pressure change amount limiting means responds to the driver's brake operation. Therefore, the driver's uncomfortable feeling can be eliminated by minimizing the interference between the driver's braking operation and automatic braking.

  According to the fourth aspect of the present invention, when the driver is operating the brake, the fluid pressure change amount limiting means delays the rise of the brake fluid pressure and accelerates the fall, so that the automatic braking is less effective. Therefore, the driver's uncomfortable feeling can be eliminated by giving priority to the driver's spontaneous braking operation. Also, when the driver is not operating the brakes, the hydraulic pressure change limiting means speeds up the brake fluid pressure and slows it down, making the automatic braking sharper and slowing down the vehicle quickly. Contact with an object can be reliably avoided.

  According to the fifth aspect of the present invention, the detection area setting means sets the detection area where the side obstacle sensor detects the obstacle on the side of the vehicle, and the target hydraulic pressure calculation means outputs the target to the braking force control means. Since the brake fluid pressure is calculated according to the distance of the obstacle on the side of the vehicle, contact with the obstacle on the side of the vehicle can be more reliably avoided by automatic braking. At this time, as the steering angle is smaller, the detection area setting means moves the rear end of the detection area to the front side of the vehicle. Therefore, the steering angle is small and the turning radius of the vehicle is large. When the possibility of contact with an obstacle is low, the rear end of the detection area is moved to the front side of the vehicle. Conversely, the steering angle is large and the turning radius of the vehicle is small. When the possibility of contact with an obstacle is high, the automatic braking for avoiding contact with the obstacle can be accurately performed by moving the rear end of the detection region to the rear side of the vehicle.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 to 6 show an embodiment of the present invention. FIG. 1 is a view showing a vehicle equipped with a contact avoidance support device, FIG. 2 is a block diagram of an electronic control unit, and FIG. FIG. 4 is a block diagram of the hydraulic pressure change amount limiting means, FIG. 5 is a block diagram of the side detection target hydraulic pressure calculating means, and FIG. 6 is an operation explanatory diagram when the vehicle passes through the crank-shaped alley. .

  As shown in FIG. 1, a four-wheeled vehicle includes a plurality of (six in the embodiment) ultrasonic sensors Sa for detecting an obstacle in front of the vehicle body on a front bumper, and the vehicle body side on the left and right vehicle body sides. A plurality of (two in the embodiment) television cameras Sb and Sb that detect the obstacle. The steering wheel 11 is provided with a steering angle sensor Sc for detecting the steering angle δ, and the left and right front wheels WFL, WFR and the left and right rear wheels WRL, WRR are provided with a vehicle speed sensor Sd. The pedal 12 is provided with a brake fluid pressure sensor Se for detecting the brake fluid pressure P, and the accelerator pedal 13 is provided with an accelerator opening sensor Sf for detecting the accelerator opening θAP. These ultrasonic sensors Sa..., Television cameras Sb and Sb, steering angle sensor Sc, vehicle speed sensor Sd..., Brake hydraulic pressure sensor Se, and accelerator opening sensor Sf are connected to an electronic control unit U that controls the braking force of the wheels. Is done.

  As shown in FIG. 2, the electronic control unit U controls the vehicle speed V via the brake caliper 14, and the target speed calculation means M1, the limit means M2, the hydraulic pressure conversion means M3, and the hydraulic pressure change amount limit. Means M4, side detection target hydraulic pressure calculation means M5, braking force control means M6, subtraction circuit 15, and addition circuits 16, 17 are provided.

  FIG. 3 shows details of the target speed calculation means M1 of the electronic control unit U. The ultrasonic sensor output selection means 18 to which the detection data of the six ultrasonic sensors Sa ... and the steering angle δ detected by the steering angle sensor Sc are input corresponds to the steering angle δ, that is, in the traveling direction of the vehicle. Accordingly, one of the outputs of the six ultrasonic sensors Sa ... is selected. That is, assuming that the detection areas of the six ultrasonic sensors Sa ... are A1 to A6 from the right side to the left side, for example, if the steering angle δ is the limit angle in the right steering direction, it corresponds to the rightmost detection area A1. If the output of the ultrasonic sensor Sa is selected and the steering angle δ is the limit angle in the left steering direction, the output of the ultrasonic sensor Sa corresponding to the leftmost detection area A6 is selected and the steering angle δ is neutral (zero) ), The average value of the outputs of the two ultrasonic sensors Sa and Sa corresponding to the two central detection areas A3 and A4 is selected. Thus, depending on the traveling direction of the vehicle, the average value of the output of one ultrasonic sensor Sa or the output of two adjacent ultrasonic sensors Sa and Sa is used, so that it exists in the traveling direction of the vehicle. The distance of the obstacle can be detected with high accuracy.

  The target speed calculation means 19 searches the map for a target speed for avoiding contact with the obstacle, using the distance of the obstacle output by the ultrasonic sensor output selection means 18 as a parameter. When the obstacle distance is small, it is difficult to avoid the collision, so the target speed is small. Conversely, when the obstacle distance is large, the collision is easy to avoid, so the target speed is large. Become.

  The steering angle δ detected by the steering angle sensor Sc is converted into an absolute value by the absolute value calculation circuit 20, and the first target speed addition amount calculation means 21 searches the map for the first target speed addition amount calculation using the absolute value as a parameter. . Further, the steering angle δ detected by the steering angle sensor Sc is differentiated by the differentiation circuit 22 to obtain the steering angular velocity dδ / dt, and then converted into an absolute value by the absolute value calculation circuit 23. The absolute value is used as a parameter for the second target. The speed addition amount calculation means 24 searches the map for the second target speed addition amount calculation. The third target speed addition amount calculation means 25 searches the map for the third target speed addition amount calculation using the accelerator opening degree θAP detected by the accelerator opening degree sensor Sf as a parameter.

  These first to third target speed addition amount calculations are added to each other in the addition circuit 26, and the addition value is added to the target speed searched for by the target speed calculation means 19 in the addition circuit 27, so that the target is obtained. The speed is corrected to a value corresponding to the steering angle δ, the steering angular speed dδ / dt, and the accelerator opening θAP.

  The first target speed addition amount searched for in the map by the first target speed addition amount calculating means 21 is larger as the steering angle δ is larger, so that when the driver is willing to steer, the first target speed addition amount is automatically It is possible to minimize a decrease in the target speed against the intention of the driver due to braking.

  Further, the second target speed addition amount calculation searched for in the map by the second target speed addition amount calculation means 24 becomes larger as the steering angular speed dδ / dt is larger, and the driver has an intention to steer. Sometimes, the automatic braking can minimize the decrease in the target speed against the driver's intention.

  Further, the third target speed addition amount map searched for by the third target speed addition amount calculation means 25 becomes larger as the accelerator opening degree θAP is larger, and thus when the driver has an intention to accelerate. Can minimize the reduction in the target speed against the driver's intention due to automatic braking.

  Thus, the target speed calculated by the target speed calculation means 19 is corrected in the increasing direction by the steering angle δ, the steering angular speed dδ / dt, and the accelerator opening θAP that are parameters indicating the driver's spontaneous contact avoidance operation. Therefore, it is possible to eliminate the driver's uncomfortable feeling by minimizing that the driver's spontaneous contact avoidance operation interferes with the automatic braking.

  2, the target speed calculated by the target speed calculation means M1 is subtracted by the subtraction circuit 15 from the vehicle speed V detected by the vehicle speed sensor Sd. This subtraction value (deviation) is subjected to limit processing within a predetermined range (for example, 0 km / h to 20 km / h) by the limit means M2, and then converted to brake hydraulic pressure by the hydraulic pressure conversion means M3. The brake hydraulic pressure output by the hydraulic pressure conversion means M3 and the brake hydraulic pressure P detected by the brake hydraulic pressure sensor Se are input to the hydraulic pressure change amount limiting means M4. Here, the brake fluid pressure sensor Se functions as a sensor that detects whether or not the brake pedal 12 is depressed, that is, a brake switch.

  FIG. 4 shows details of the hydraulic pressure change limiting means M4 of the electronic control unit U. The hydraulic pressure change amount limiting means M4 includes a first target brake hydraulic pressure limit value calculating means 28 and a second target brake hydraulic pressure limit for limiting the target brake hydraulic pressure with the brake hydraulic pressure output from the hydraulic pressure conversion means M3 as a parameter. The value calculating means 29 is provided, and the selecting means 30 is a limit value of the first target brake fluid pressure limit value calculating means 28 when the brake pedal 12 is depressed, that is, when the brake fluid pressure P is not less than a predetermined value. When the brake pedal 12 is not depressed, that is, when the brake fluid pressure P is less than a predetermined value, the limit value of the second target brake fluid pressure limit value calculating means 29 is output.

  The limit value of the first target brake fluid pressure limit value calculation means 28 selected when the brake pedal 12 is depressed increases gently when the brake fluid pressure rises, and decreases rapidly when the brake fluid pressure falls. It is set to be. The reason is that when the driver is voluntarily operating the brake to avoid contact with an obstacle, the driver's braking operation is given priority by minimizing the braking force intervention by automatic braking. is there.

  On the other hand, the limit value of the second target brake fluid pressure limit value calculation means 29 selected when the brake pedal 12 is not depressed increases rapidly when the brake fluid pressure rises and becomes medium when the brake fluid pressure falls. It is set to decrease at a moderate speed. The reason is that when the driver is not performing a brake operation to avoid contact with an obstacle, a braking force by automatic braking is effectively generated.

  FIG. 5 shows details of the side detection target hydraulic pressure calculation means M5 of the electronic control unit U. If the direction of the steering angle δ detected by the steering angle sensor Sc is on the right side, the detection area setting means 31 sets the detection area by the television cameras Sb and Sb to the right side of the vehicle body, and the direction of the steering angle δ is on the left side. For example, the detection area by the television cameras Sb and Sb is set on the left side of the vehicle body. Based on the absolute value of the steering angle δ calculated by the absolute value calculation circuit 32, the detection permission x-coordinate calculation means 33 sets the x-coordinate of the front end of the detection area.

  The detection area setting unit 31 sets the rear end of the detection area according to the x coordinate. That is, in the Cartesian coordinate system having the x axis along the longitudinal direction of the vehicle body and the y axis along the lateral direction of the vehicle body, the smaller the absolute value of the steering angle δ, that is, the smaller the steering wheel 11 is operated, Is set to be small, the rear end of the detection area is moved to the front side of the vehicle body. Conversely, the larger the absolute value of the steering angle δ, that is, the greater the steering wheel 11 is operated, the larger the x coordinate of the rear end of the detection area is set, and the rear end of the detection area is moved to the rear side of the vehicle body. Let

  The reason for this is that when the steering angle δ is small, the turning radius of the vehicle becomes large, so that the difference between the inner wheels becomes small and the possibility of coming into contact with an obstacle near the rear of the vehicle becomes low. This is because there is no problem even if the vehicle is moved to the front side of the vehicle. Conversely, when the steering angle δ is large, the turning radius of the vehicle is small, so the difference between the inner wheels is large, and there is a high possibility that the vehicle will come into contact with an obstacle near the rear of the vehicle. This is because it is necessary to move to the vehicle rear side to avoid contact with an obstacle.

  The target hydraulic pressure calculation means 34 searches the map for the target hydraulic pressure for automatic braking using the y coordinate of the obstacle detected by the television camera Sb in the detection area set by the detection area setting means 31 as a parameter. The target hydraulic pressure for the automatic braking is set to be larger as the detection distance of the obstacle in the y-axis direction is smaller. The reason is that the smaller the detection distance in the y-axis direction of an obstacle, the easier it is to touch the obstacle, and therefore it is necessary to reduce the vehicle speed by automatic braking.

  In addition, there is a hysteresis in the target hydraulic pressure of the automatic braking, and when automatic braking is started by gradually approaching an obstacle, the target hydraulic pressure rises sharply to prevent contact with the obstacle. When the automatic braking is finished gradually away from the obstacle, the falling of the target hydraulic pressure is moderated to prevent the vehicle from suddenly accelerating and the driver's uncomfortable feeling is eliminated.

  The correction coefficient calculating means 35 searches the map for the correction coefficient using the vehicle speed V detected by the vehicle speed sensor Sd as a parameter. The correction coefficient is set to 1 when the vehicle speed V is low, and becomes larger than 1 when the vehicle speed V increases. The multiplier circuit 36 corrects the target hydraulic pressure by multiplying the target hydraulic pressure output by the target hydraulic pressure calculating means 34 by the correction coefficient. Therefore, when the vehicle speed V is high and the possibility of contact with an obstacle is high, the target hydraulic pressure is increased to increase the braking force of automatic braking, thereby avoiding contact with the obstacle.

  Returning to FIG. 2, the correction target hydraulic pressure output by the hydraulic pressure change amount limiting means M4 and the target hydraulic pressure output by the side detection target hydraulic pressure calculating means M5 are added by the adding circuit 16. Further, the brake fluid pressure detected by the brake fluid pressure sensor Se, that is, the brake fluid pressure generated by the driver's brake operation, and the brake fluid pressure output from the adder circuit 16 are added by the adder circuit 17, and the final result is obtained. The braking force control means M6 operates the brake caliper 14 to brake the wheel using the brake fluid pressure as a command value, thereby assisting in avoiding contact with an obstacle.

  FIG. 6 illustrates the operation when a vehicle equipped with the contact avoidance assistance device of the present embodiment passes through a narrow crank-shaped alley.

  When the vehicle reaches the position A at the entrance to the crank-shaped alley, the ultrasonic sensor Sa detects the obstacle a in front, whereby deceleration by automatic braking is performed. At the position B where the steering wheel 11 is turned to the right and then turned back to the left, the steering angular speed dδ / dt is increased, so that the second target speed addition amount calculated by the second target speed addition amount calculation means 24 in FIG. 3 is increased. By increasing the target speed by the second target speed addition amount, it is possible to pass the B position while minimizing unnecessary automatic braking. When the vehicle approaches the C position at the exit of the crank-shaped alley, the steering angle δ to the left of the steering wheel 11 increases, so the first target speed addition calculated by the first target speed addition amount calculation means 21 in FIG. By increasing the amount and increasing the target speed by the amount of the first target speed addition amount, it is possible to pass the C position while minimizing unnecessary automatic braking.

  Meanwhile, when the distance between the obstacle b at the right corner and the obstacle c at the left corner of the alley detected by the television cameras Sb and Sb is reduced, the target hydraulic pressure calculated by the target hydraulic pressure calculation unit 34 in FIG. 5 is increased. As a result, the braking force of automatic braking is increased, the vehicle is decelerated, and contact with the obstacles b and c can be avoided in advance.

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

  For example, in the embodiment, the ultrasonic sensor Sa ... is used as the front obstacle sensor and the television cameras Sb, Sb are used as the side obstacle sensor, but a sensor having any other structure is adopted. Can do.

A diagram showing a vehicle equipped with a contact avoidance support device Block diagram of electronic control unit Block diagram of target speed calculation means Block diagram of hydraulic pressure change limiting means Block diagram of side detection target hydraulic pressure calculation means Action diagram when the vehicle passes through a crank-shaped alley

Explanation of symbols

M1 target speed calculation means M3 hydraulic pressure conversion means M4 hydraulic pressure change amount limiting means M6 braking force control means Sa ultrasonic sensor (front obstacle sensor)
Sb TV camera (side obstacle sensor)
21. First target speed addition amount calculation means (target speed correction means)
24 Second target speed addition amount calculation means (target speed correction means)
25 Third target speed addition amount calculation means (target speed correction means)
31 Detection area setting means 34 Target hydraulic pressure calculation means δ Steering angle dδ / dt Steering angular velocity θAP Accelerator opening

Claims (5)

A vehicle contact avoidance assistance device that generates a braking force that assists in avoiding contact with an obstacle according to the state of the obstacle ahead of the vehicle,
A front obstacle sensor (Sa) for detecting the distance of an obstacle in front of the vehicle;
Target speed calculation means (M1) for calculating a target speed of the vehicle according to the distance of the obstacle detected by the front obstacle sensor (Sa);
Target speed correction means (21, 24, 25) for correcting the target speed according to the operating state of the vehicle by the driver;
Braking force control means (M6) for controlling the braking force based on the target speed corrected by the target speed correction means (21, 24, 25);
A vehicle contact avoidance assistance device comprising:   2. The vehicle contact according to claim 1, wherein an operation state of the vehicle by the driver is any one of a steering angle (δ), a steering angular velocity (dδ / dt), and an accelerator opening (θAP). Avoidance support device.   Fluid pressure conversion means (M3) for converting the deviation between the target speed and the actual vehicle speed into brake fluid pressure, and fluid pressure change amount limiting means for limiting the amount of change in the brake fluid pressure according to the driver's brake operation ( The vehicle contact avoidance assistance device according to claim 1 or 2, characterized by comprising M4).   The hydraulic pressure change limiting means (M4) slows down the rise of the brake fluid pressure when the driver is operating the brake, and accelerates the fall when the driver is not operating the brake. 4. The contact avoidance assistance device for a vehicle according to claim 3, wherein the rising of the hydraulic pressure is accelerated and the falling is delayed. A side obstacle sensor (Sb) for detecting an obstacle on the side of the vehicle, a detection area setting means (31) for setting a detection area of the side obstacle sensor (Sb), and a side obstacle sensor (Sb) And a target hydraulic pressure calculating means (34) for calculating a target brake hydraulic pressure to be output to the braking force control means (M6) according to the distance of the obstacle on the side of the vehicle detected in step (a). 5. The vehicle contact avoidance support according to claim 1, wherein the rear end of the detection area is moved to the front side of the vehicle as the steering angle (δ) is smaller. apparatus.

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