JP2007210593A - Automatic braking control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve automatic braking control in a truck or a bus. <P>SOLUTION: When TTC derived based upon the relative distance and the relative speed of an object and an own vehicle is under a preset value, automatically stepped braking control for gradually increasing braking force or braking deceleration in two or more stages is time-series conducted. At this time, a warning for the start of braking control is given to the other vehicle. Further, when the vehicle width of the vehicle ahead is detected and it is a large vehicle, a braking lamp is flickered to surely give a warning to the following vehicle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is used for large vehicles (trucks, buses) for transporting cargo and passengers.

  The electronic control of automobiles has progressed steadily, and events that have so far depended solely on the judgment of the driver have been carried out by onboard computers.

  As an example, the distance between the preceding vehicle and the host vehicle (inter-vehicle distance) is monitored by a radar, and when the inter-vehicle distance approaches abnormally, appropriate braking control is automatically performed to prevent a collision. Sometimes, there is an automatic braking control device that minimizes the damage (see, for example, Patent Document 1).

JP 2005-31967 A

  The above-described automatic braking control device has already been put into practical use in passenger cars, but it must be solved when a similar function is to be used for large vehicles (trucks, buses) for transporting cargo and passengers. There is a problem that must be done.

  In other words, large vehicles have an extremely large mass compared to passenger cars, and in addition to the driver's own safety, the safety of passengers and cargo must be ensured. It is difficult to achieve the intended purpose with simple simple braking control, and it is necessary to perform more advanced automatic braking control than in the case of passenger cars. However, since such means has not been established, automatic braking control devices for trucks and buses have not yet been put into practical use.

  The present invention has been made under such a background, and an object thereof is to provide an automatic braking control device that can realize automatic braking control in a truck or a bus.

  The present invention is an automatic braking control device provided with a control unit that automatically performs braking control without a driving operation based on a sensor output including a distance from an object in the traveling direction of the host vehicle.

  Here, the feature of the present invention is that the control means includes the object and the vehicle derived based on a relative distance and a relative speed between the object and the vehicle obtained by the sensor output. When the predicted value of the time required for the distance to fall below the predetermined distance falls below the set value, stepwise braking control is performed to gradually increase the braking force or braking deceleration over multiple stages in time series Stepwise braking control means is provided, and this stepwise braking control means is provided with means for warning other vehicles of the start of braking control.

  The predicted value of the time required for the object and the vehicle to be less than a predetermined distance derived based on the relative distance and relative speed between the object and the vehicle is, for example, the object and the vehicle Is a predicted value of the time required for the collision (hereinafter referred to as TTC (Time To Collision)).

  That is, the automatic braking control device of the present invention is a device that can reduce the impact at the time of collision while maintaining the stability of the vehicle even in large vehicles such as trucks and buses by performing stepwise braking control. is there. In carrying out such automatic braking control, large vehicles have a significantly larger mass than passenger cars, so there is a significant impact on other vehicles in the event of an emergency, and the vehicle is currently under automatic braking control. It is necessary to reliably warn other vehicles that there is Therefore, the automatic braking control device of the present invention includes means for warning other vehicles of the start of braking control.

  The warning means includes, for example, a lighting control means that turns on or blinks a brake lamp or a hazard lamp in synchronization with the start of braking control. Furthermore, vehicle width detection means for detecting the vehicle width of the preceding vehicle is provided, and the lighting control means brakes in synchronization with the start of braking control when the detection result of the vehicle width detection means exceeds a predetermined value. Means may be provided for blinking the lamp.

  In other words, if the preceding vehicle is a small car such as a passenger car, even if it collides, it is unlikely that the large vehicle will suddenly stop due to the collision. In the case of a large vehicle, in the unlikely event of a collision, there is a high possibility that the vehicle will stop suddenly due to the collision. Therefore, by detecting the width of the preceding vehicle, it is determined whether or not the preceding vehicle is a large vehicle similar to the own vehicle. If the preceding vehicle is also a large vehicle similar to the own vehicle, the vehicle stops suddenly. It is expected that the following vehicle will be affected by the above, so that the following vehicle is reliably warned by blinking the brake lamp.

  Further, the alarming means may include means for sounding a horn in addition to lighting or blinking of a brake lamp or a hazard lamp at least in the final stage of the stepwise braking control.

  According to this, it is possible to alert not only the following vehicle but also any other surrounding vehicles, and alert the other vehicle. In the initial stage of braking control, there is still a possibility that a collision can be avoided by the driver's operation. We will start from the final stage or near it.

  In addition, when the host vehicle speed is less than a predetermined value and the value taken by the steering angle or yaw rate is out of the predetermined range, a means for prohibiting activation of the stepwise braking control means can be provided.

  That is, the stepwise braking control performed by the automatic braking control device of the present invention is, for example, when the vehicle speed before starting the braking control is 60 km / h or more, and a large steering wheel operation such as when changing lanes or driving sharp curves is performed. Since it is assumed to be used in a state where it is not performed, the start of the stepwise braking control can be restricted in other traveling states.

  For example, if the vehicle speed before the start of braking control is less than 60 km / h, the vehicle has less kinetic energy, so there is no problem even if simple sudden braking control as conventionally applied to passenger cars is performed. Limit the start of stepwise braking control. Also, for example, if the steering angle before starting the braking control is + 30 ° or more or −30 ° or less, this means that the vehicle is changing lanes or driving in a sharp curve. Restrict. In this case, a yaw rate may be used instead of the steering angle.

  According to the present invention, automatic braking control in a truck or bus can be realized.

  An automatic braking control apparatus according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a control system configuration diagram of the present embodiment. FIG. 2 is a diagram for explaining the vehicle width detection method of this embodiment. FIG. 3 is a flowchart showing the vehicle width detection procedure of this embodiment. FIG. 4 is a flowchart showing a control procedure of a braking control ECU (Electric Control Unit) of the present embodiment. FIG. 5 is a diagram showing a braking pattern at the time of the idle control that the braking control ECU has. FIG. 6 is a diagram showing a braking pattern at the time of half product of the braking control ECU. FIG. 7 is a diagram showing a braking pattern at the time of fixed volume possessed by the braking control ECU. FIG. 8 is a diagram showing a full-scale braking pattern that the braking control ECU has.

  As shown in FIG. 1, the braking control ECU 4, the gateway ECU 5, the meter ECU 6, the engine ECU 8, the axle weight meter 9, the EBS (Electric Breaking System) _ECU 10, and the lighting / horn control ECU 15 are connected to each other via a VehicleCAN (J1939) 7. The

  The steering sensor 2, the yaw rate sensor 3, and the vehicle speed sensor 13 are connected to the VehicleCAN (J1939) 7 via the gateway ECU 5, and the sensor information is taken into the braking control ECU 4. The brake control is performed by the EBS_ECU 10 driving the brake actuator 11. Note that the brake instruction to the EBS_ECU 10 is performed by the brake operation and braking control ECU 4 at the driver's seat (not shown). The brake information including information on the brake operation by the driver is also output from the EBS_ECU 10 and taken into the brake control ECU 4. The engine ECU 8 performs fuel injection amount control of the engine 12 and other engine control. Note that the injection amount control instruction to the engine ECU 8 is performed by the accelerator operation of the driver's seat. Further, the alarm display and buzzer sound output by the braking control ECU 4 are displayed on the display unit (not shown) of the driver's seat by the meter ECU 6. Since the control system related to steering other than the steering sensor 2 is not directly related to the present invention, the illustration is omitted.

  In this embodiment, as shown in FIG. 1, a millimeter wave radar 1 for measuring a distance from a preceding vehicle or a falling object such as a falling object in the traveling direction of the own vehicle, a steering sensor 2 for detecting a steering angle, This is an automatic braking control device including a braking control ECU 4 that automatically performs braking control based on sensor outputs such as a yaw rate sensor 3 for detecting the yaw rate and a vehicle speed sensor 13 for detecting the host vehicle speed without any driving operation. .

  The braking control ECU 4 automatically detects when the TTC derived based on the relative distance and relative speed between the object and the vehicle obtained from the sensor outputs from the millimeter wave radar 1 and the vehicle speed sensor 13 falls below a set value. Stepwise braking control. In this stepwise braking control, as shown in FIG. 5B, the braking force is gradually increased over three stages in time series.

  Here, the feature of this embodiment is that the braking control ECU 4 includes an alarm control unit 16 that warns other vehicles of the start of the braking control. The alarm control unit 16 includes a lighting control unit 17 that turns on or blinks a brake lamp or a hazard lamp in synchronization with the start of braking control. The lamp control unit 17 can turn on or blink the brake lamp and the hazard lamp by sending a lamp control instruction to the lamp / horn control ECU 15.

  Further, a vehicle width detection device 14 for detecting the vehicle width of the preceding vehicle is provided, and the lighting control unit 17 synchronizes with the start of braking control when the detection result of the vehicle width detection device 14 exceeds a predetermined value. To make the brake lamp blink. Further, the alarm control unit 16 includes a horn control unit 18 that causes a horn to sound in addition to lighting or blinking of a brake lamp or a hazard lamp at least in the final stage of the stepwise braking control. The horn control unit 18 can sound the horn by sending a horn control instruction to the lighting / horn control ECU 15.

  Here, the vehicle width detection method and procedure by the vehicle width detection device 14 will be described with reference to FIGS. As shown in FIG. 3, the vehicle width detection device 14 acquires inter-vehicle distance information with the preceding vehicle (S1). This inter-vehicle distance information can be acquired from the radar information of the millimeter wave radar 1.

  The vehicle width detection method in this embodiment employs a method of analyzing the image of the preceding vehicle at a predetermined inter-vehicle distance and detecting the vehicle width. That is, an image taken by a camera (not shown) at a predetermined inter-vehicle distance reflects the vehicle width ratio between the passenger car and the large vehicle on the image, as shown in FIG. For example, an image of a large vehicle as shown in FIG. 2 (c) is taken larger than an image of a passenger car as shown in FIGS. 2 (a) and 2 (b). Therefore, the actual vehicle width can be estimated by measuring the vehicle width on the image.

  Thus, the vehicle width is measured by image analysis (S3), and the vehicle width detection information is output to the braking control ECU 4 (S4).

  In the example of FIG. 5B, the braking control ECU 4 first applies braking of about 0.1 G from TTC 2.4 seconds to 1.6 seconds in the first stage marked “alarm”. At this stage, the so-called sudden braking is not yet applied, and the stop lamp and the hazard lamp are turned on, so that the succeeding vehicle can be notified that the sudden braking will be performed. At this time, if the vehicle width detection result of the preceding vehicle is 2 m or more, it is determined that the preceding vehicle is a large vehicle, and the brake lamp is blinked.

  Next, in the second stage described as “enlarged area braking”, braking of about 0.3 G is applied from TTC 1.6 seconds to 0.8 seconds. At this time, the brake lamp and the hazard lamp are lit or blinking. Finally, in the third stage, marked as “full-scale braking”, the maximum braking (about 0.5 G) is applied from TTC 0.8 seconds to 0 seconds. At this time, in addition to the lighting or blinking of the brake lamp and the hazard lamp, the horn is also sounded to warn other vehicles other than the following vehicle.

  When the driver performs a strong braking operation exceeding the braking force shown above, the stronger braking force is given priority.

  In the present embodiment, as shown in FIGS. 5 to 7, the braking control ECU 4 includes a braking pattern selection unit 40 that changes the braking pattern according to the weight of the loaded cargo or the passenger. As a method of changing, the braking pattern storage unit 41 of the braking control ECU 4 stores in advance a plurality of control patterns for “empty product”, “half product”, and “constant product”, and the braking pattern selection unit 40. Can be realized by selecting a braking pattern that matches (or approximates) from these braking patterns according to the weight. The weight information of the loaded cargo and passengers is obtained by the axle weight meter 9 shown in FIG. 1 and is taken into the braking control ECU 4.

  In the following description, the preceding vehicle will be described, but the automatic braking control device of this embodiment is also effective for falling objects on the road.

  Further, when the host vehicle speed is less than 60 km / h and the steering angle is not less than +30 degrees or not more than -30 degrees, the braking control ECU 4 prohibits the start of the stepwise braking control. A yaw rate may be used instead of the steering angle.

  In other words, the stepwise braking control performed by the automatic braking control device of this embodiment is such that the host vehicle speed before starting the braking control is 60 km / h or more, and a large steering wheel operation such as when changing lanes or driving sharp curves is performed. Since it is assumed that the vehicle is not used, it is possible to limit the start of the stepwise braking control in other driving conditions.

  Also, if the vehicle speed before the start of braking control is less than 60 km / h, the vehicle has less kinetic energy, so there is no problem even if simple sudden braking control as conventionally applied to passenger cars is performed. Since the usefulness of performing stepwise braking control is low, the activation of stepwise braking control is limited. Alternatively, if the steering angle before the start of the braking control is +30 degrees or more or -30 degrees or less, this means that the vehicle is changing lanes or traveling sharply. Restrict startup of. In this case, a yaw rate may be used instead of the steering angle.

  In this embodiment, when the host vehicle speed before the start of braking control is less than 60 km / h and is 15 km / h (minimum speed at which the usefulness of automatic braking control (full-scale braking control) is recognized) or more, stepwise Although braking control is not performed, as shown in FIG. 8, only full-scale braking control shown in FIGS. 5B to 7B is performed. When only such full-scale braking control is performed, braking control equivalent to conventional automatic braking control used in passenger cars can be applied. Note that when applying such automatic braking control equivalent to the conventional one, there is no need to determine whether or not the vehicle is changing lanes or traveling sharply.

  Next, the operation of the automatic braking control apparatus of this embodiment will be described with reference to the flowchart of FIG. FIG. 4 will be described with reference to an example of a braking pattern at the time of idle product (FIG. 5), but the procedure of the flowchart of FIG. 4 is also followed at the time of half product (FIG. 6) or constant product (FIG. 7). As shown in FIG. 4, the braking control ECU 4 measures and monitors the inter-vehicle distance from the preceding vehicle and the vehicle speed of the preceding vehicle by the millimeter wave radar 1. Further, the vehicle speed is measured by the vehicle speed sensor 13 and monitored. Further, the weight of the loaded cargo and passengers is measured and monitored by the axle weight meter 9. The braking pattern selection unit 40 of the braking control ECU 4 selects in advance one of the braking patterns (FIGS. 5 to 7) based on the measurement result of the weight (S11). The following description is an example in which the braking pattern of FIG. 5 is selected.

Subsequently, the braking control ECU 4 calculates TTC from the inter-vehicle distance, the own vehicle speed, and the vehicle speed of the preceding vehicle (S12). The calculation method is
Distance between vehicles / (Self-vehicle speed-Vehicle speed of the preceding vehicle)
It is. In the braking control ECU 4, the vehicle speed before starting the braking control is 60 km / h or more (S13), the steering angle before starting the braking control is +30 degrees or less and -30 degrees or more (S14), and the TTC is shown in FIG. If it exists in the area | region of (1) shown to (a) (S15), a brake lamp and a hazard lamp will be lighted (S18). Furthermore, if the vehicle width based on the vehicle width detection information output from the vehicle width detection device 14 is 2 m or more (S19), the brake lamp is blinked (S20). The hazard lamp is blinking from the beginning. Then, “alarm” braking control is executed (S21). Further, if the TTC is in the region (2) shown in FIG. 3A (S16), the brake lamp and the hazard lamp in the “alarm” are kept on or blinking and “enlarged region braking” control is executed. (S22). If the TTC is in the region (3) shown in FIG. 3A (S17), the brake lamp and hazard lamp in the “enlarged region braking” are kept on or blinking, and the horn is sounded. “Full-scale braking” control is executed (S23).

  Also, if the host vehicle speed before starting the braking control is less than 60 km / h and 15 km / h or more (S13, S24) and the TTC is in the region (4) shown in FIG. 3C (S25), the braking control ECU 4 Notifies the driver that the relative distance from the preceding vehicle is short (S26). Notification is performed by warning display or buzzer sound. Further, if the TTC is in the region (5) shown in FIG. 3C (S27), the brake lamp and the hazard lamp are turned on or blinked, the horn is sounded, and "full-scale braking" control is executed (S23). .

  Note that the yaw rate from the yaw rate sensor 3 can be used instead of the steering angle from the steering sensor 2. Alternatively, the steering angle and the yaw rate may be used in combination.

  Here, FIG. 5 to FIG. 7 will be described. The straight lines c, f, i in FIGS. 5 to 7 are called steering avoidance limit straight lines. Moreover, the curves B, D, and F in FIGS. 5 to 7 are called braking avoidance limit curves.

  That is, the steering avoidance limit straight line is a straight line indicating a limit at which a collision can be avoided by a steering operation within a predetermined TTC in the relationship between one relative distance to the obstacle and one relative speed with the obstacle. The braking avoidance limit curve is a curve indicating a limit at which a collision can be avoided by a braking operation within a predetermined TTC in the relationship between one relative distance to the obstacle and one relative speed with the obstacle.

  In FIG. 5 to FIG. 7, in the area under both of these straight lines or curves, the collision can no longer be avoided by the steering operation or the braking operation.

  For example, in the example of the empty product in FIG. 5, the straight line c has TTC set to 0.8 seconds. In the present embodiment, a straight line b when the TTC is 1.6 seconds is provided above the steering avoidance limit straight line c, and a straight line a when the TTC is 2.4 seconds is provided. Further, a curve A with TTC set at 1.6 seconds is provided above the braking avoidance limit curve B with TTC set at 0.8 seconds.

  The initial state of the vehicle has a relative distance and a relative speed with respect to the obstacle indicated by a black point G in FIG. When the host vehicle speed before the start of braking control is 60 km / h or more, the relative distance gradually decreases, and when the vehicle reaches the position of the straight line a, the alarm mode is set (area (1)). In the alarm mode, braking of about 0.1 G is applied from TTC 2.4 seconds to 1.6 seconds. During this period, the stop lamp and the hazard lamp are turned on or blinked, and it is meaningful to inform that the subsequent vehicle is braked. When the relative speed further decreases and reaches the position of the straight line b, the expansion area braking mode is set (area (2)). In the enlarged area braking mode, braking of about 0.3 G is applied from TTC 1.6 seconds to 0.8 seconds. In addition, the brake lamp and the hazard lamp are turned on or blinking following the “alarm”. When the position of the straight line c is reached, the full braking mode is set (area (3)). In the full-scale braking mode, the maximum braking (about 0.5G) is applied from TTC 0.8 seconds to 0 seconds. In addition, the brake lamp and the hazard lamp are turned on or blinked, and the horn is sounded. According to the calculation in step S12 in FIG. 4, a collision occurs at this time. However, the actual TTC is longer than the calculation result of step S12.

  In other words, in the calculation of TTC in the automatic braking control device targeted by the present invention, precise distance measurement and complicated calculation processing are omitted as much as possible, and a general-purpose simple distance measurement device (for example, millimeter wave radar) or a calculation device is used. It is assumed that. Such considerations are useful for keeping vehicle manufacturing costs or maintenance costs low.

  Therefore, strictly speaking, the preceding vehicle and the subject vehicle, which are the objects, are performing a uniform acceleration motion by braking (deceleration), and therefore the TTC calculation must also be calculated based on the uniform acceleration motion. By calculating the TTC as simply performing constant velocity motion, precise distance measurement and complicated arithmetic processing are omitted.

  In addition, by performing a calculation that is regarded as such a constant velocity motion, the calculated TTC value becomes smaller than the actual TTC value. There is no hindrance.

  Further, when the host vehicle speed before starting the braking control is 15 km / h or more and less than 60 km / h, the relative distance is gradually shortened, and when the vehicle reaches the position of the straight line b, the notification mode is set (region (4)). . In the notification mode, the driver is notified that the relative distance to the obstacle is shortened by an alarm display or a buzzer sound. When the position of the straight line c is reached, the full braking mode is set (area (5)). In the full-scale braking mode, the maximum braking (about 0.5G) is applied from TTC 0.8 seconds to 0 seconds. In addition, the brake lamp and the hazard lamp are turned on or blinked, and the horn is sounded.

  FIG. 6 shows an example of half-loading, and FIG. 7 shows an example of fixed-loading. Compared with equal braking forces, the braking distance increases as the weight of loaded cargo and passengers increases. The avoidance limit straight line and the braking avoidance limit curve also move upward in the figure. Thereby, the area of area | region (1), (2), (3), (4), (5) becomes large according to the weight of a loaded cargo or a passenger.

  The straight lines a to c in FIG. 5 correspond to the straight lines df to f in FIG. 6 and the straight lines g to i in FIG. 7, and the curves A and B in FIG. 5 are the curves C and D in FIG. , F, the black point G in FIG. 5 corresponds to the black point H in FIG. 6 and the black point I in FIG.

  ADVANTAGE OF THE INVENTION According to this invention, the automatic braking control in a truck or a bus | bath can be implement | achieved, and it can contribute to traffic safety.

The control system block diagram of a present Example. The figure for demonstrating the vehicle width detection method of a present Example. The flowchart which shows the vehicle width detection procedure of a present Example. The flowchart which shows the control procedure of braking control ECU of a present Example. The figure which shows the 1st braking pattern at the time of the idle product which braking control ECU has. The figure which shows the 1st braking pattern at the time of the half product which braking control ECU has. The figure which shows the 1st braking pattern at the time of the fixed volume which braking control ECU has. The figure which shows the full-scale braking pattern which braking control ECU has.

Explanation of symbols

1 Millimeter wave radar 2 Steering sensor 3 Yaw rate sensor 4 Braking control ECU
5 Gateway ECU
6 Meter ECU
7 VehicleCAN (J1939)
8 Engine ECU
9 Shaft weigher 10 EBS_ECU
11 Brake actuator 12 Engine 13 Vehicle speed sensor 14 Vehicle width detection device 15 Light / horn control ECU
16 Alarm control unit 17 Light control unit 18 Horn control unit 40 Braking pattern selection unit 41 Braking pattern storage unit

Claims (5)

In an automatic braking control device including a control unit that automatically performs braking control without a driving operation based on a sensor output including a distance from an object in the traveling direction of the host vehicle,
The control means predicts the time required for the object and the vehicle, which are derived based on the relative distance and relative speed between the object and the vehicle obtained from the sensor output, to be equal to or less than a predetermined distance. Stepwise braking control means for performing stepwise braking control that gradually increases braking force or braking deceleration gradually over a plurality of stages in a time series manner when a value falls below a set value,
The stepwise braking control means comprises means for warning other vehicles of the start of braking control.   2. The automatic braking control device according to claim 1, wherein the warning means includes a lighting control means for lighting or blinking a brake lamp or a hazard lamp in synchronization with the start of the braking control. Vehicle width detection means for detecting the vehicle width of the preceding vehicle is provided;
The automatic braking control device according to claim 1, wherein the lighting control means includes means for blinking a brake lamp in synchronization with the start of braking control when the detection result of the vehicle width detection means exceeds a predetermined value.   2. The automatic braking control device according to claim 1, wherein the warning means includes means for sounding a horn in addition to lighting or blinking of a brake lamp or a hazard lamp at least in the final stage of the stepwise braking control.   2. The automatic braking control device according to claim 1, further comprising means for prohibiting the stepwise braking control means from starting when the host vehicle speed is less than a predetermined value and the value of the steering angle or yaw rate is outside the predetermined range.

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