JP4525409B2 - Vehicle travel control device - Google Patents

Description

  The present invention relates to a vehicular travel control device, and more particularly to a vehicular travel control device that controls a vehicle to travel following a preceding vehicle.

  In recent years, in order to reduce the operational burden on a driver who drives a vehicle, a vehicular travel control device has been developed that travels the vehicle following a preceding vehicle traveling ahead. In such a travel control device, for example, the acceleration of the host vehicle is controlled such that the inter-vehicle distance between the preceding vehicle and the host vehicle detected by a sensor such as a camera or a radar becomes the target inter-vehicle distance.

As such a travel control device, there is a preceding vehicle follow-up control device disclosed in JP-A-11-59222. The follow-up control device determines the inter-vehicle distance detection value as the target inter-vehicle distance based on a value obtained by multiplying the detected inter-vehicle distance between the preceding vehicle, the deviation between the target inter-vehicle distance and the relative speed calculation value by a predetermined gain. Vehicle speed calculating means for calculating a target vehicle speed for the purpose. Further, the vehicle speed is detected, and the braking / driving force of the vehicle is controlled so that the detected value of the vehicle speed becomes the target vehicle speed.
JP 11-59222 A

  However, in the follow-up control device disclosed in Patent Literature 1, the braking / driving force is controlled based on the relative speed and the inter-vehicle distance deviation without considering the timing for starting deceleration of the host vehicle. For this reason, when the inter-vehicle distance between the host vehicle and the preceding vehicle is large, the host vehicle does not start to decelerate unless the speed of the host vehicle becomes larger than the speed of the preceding vehicle. Therefore, since the vehicle is decelerated greatly after the distance between the vehicles is extremely reduced, there is a possibility that the driver may feel uneasy and the deceleration must be increased.

  Therefore, the subject of the present invention is that the driver can start to decelerate the vehicle before the distance between the preceding vehicle and the host vehicle is greatly reduced in the follow-up control of the preceding vehicle. An object of the present invention is to provide a vehicle travel control device that can be reduced in size and avoid large deceleration.

The vehicular travel control apparatus according to the present invention that has solved the above problems is for a vehicle that controls the braking / driving force so that the relative position relationship with the target object detected by the object detection means becomes the set target relative position relationship. In the travel control device, a first calculation means for calculating a first target acceleration based on a deviation and a relative speed between the target relative positional relationship and the relative positional relationship, a deviation between the target relative positional relationship and the relative positional relationship, based on the pattern of the set target acceleration, and calculates the calculated target acceleration, calculated calculated target acceleration, when it is less than previously whether set rapid deceleration occurs state of the reference value, the calculated target acceleration And a second calculation means for setting a second target acceleration, and for controlling the braking / driving force of the vehicle based on a minimum value of the first target acceleration and the second target acceleration.

  The vehicle travel control apparatus according to the present invention provides a speed control amount until the relative positional relationship satisfies the target relative positional relationship based on a deviation between the target relative positional relationship and the relative positional relationship and a preset speed control pattern. Second calculation means for calculating the pattern is provided. In the second calculation means, when the calculated speed control amount obtained by the calculated speed control amount pattern is equal to or less than a predetermined value set in advance, the obtained calculated speed control amount is adopted as the speed control amount. . For this reason, the deceleration of the host vehicle can be started before the distance between the preceding vehicle and the host vehicle is greatly reduced. Accordingly, it is possible to reduce anxiety given to the driver and to avoid a large deceleration of the host vehicle.

  The “speed control amount” as used in the present invention refers to an amount that can control the vehicle speed as a result of the control, such as an acceleration control amount and a driving force control amount, in addition to a speed control amount that directly controls the vehicle speed. Is included.

Here, the second calculation means sets the preset target acceleration maximum value as the second target acceleration when the calculated target acceleration is equal to or greater than a reference value indicating whether or not a preset sudden deceleration occurs. It can be set as an aspect.
Further, the second calculation means may be configured to calculate a target acceleration when reaching the target relative position relationship at a constant deceleration based on the current relative position relationship and relative speed as the calculated target acceleration .

Further, the first calculation means may be configured to calculate the first target acceleration based on a deviation between the target relative positional relationship and the current relative positional relationship, a relative speed , and a control gain associated therewith.

  According to the vehicle travel control device of the present invention, it is possible to start the deceleration of the host vehicle before the distance between the preceding vehicle and the host vehicle is greatly reduced, and to reduce anxiety given to the driver. A large deceleration can be avoided.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block configuration diagram of a vehicle travel control apparatus according to the present invention, and FIG. 2 is a block configuration diagram of a tracking target acceleration calculation unit.

  As shown in FIG. 1, the vehicle travel control apparatus according to the present embodiment includes a target acceleration calculation unit 1. The target acceleration calculation unit 1 is provided with a recognition unit 2, a target acceleration candidate calculation unit 3, an arbitration unit 4, and a change rate limiting unit 5. In addition, a distance sensor 11, a CCD camera 12, a vehicle speed sensor 13, and an actuator selection unit 14 are connected to the target acceleration calculation unit 1. Further, the target acceleration candidate calculation unit 3 is provided with a follow-up target acceleration calculation unit 20, a constant speed target acceleration calculation unit 30, and a corner acceleration prohibition target acceleration calculation unit 40. The tracking target acceleration calculation unit 20 includes a steady running state target acceleration calculation unit 21, a deceleration timing determination target acceleration calculation unit 22, and a selection unit 23.

  The distance sensor 11 is composed of, for example, a millimeter wave radar sensor attached to the tip of the host vehicle, and detects the distance (actual vehicle distance) from the preceding vehicle that is the target object of the present invention located in front of the host vehicle. Yes. The distance sensor 11 transmits the detected actual inter-vehicle distance between the preceding vehicle and the host vehicle to the recognition unit 2 in the target acceleration calculation unit 1. The CCD camera 12 is provided in the vicinity of the windshield of the host vehicle, for example, and takes an image in front of the host vehicle. The CCD camera 12 transmits the captured image to the recognition unit 2 in the target acceleration calculation unit 1. The vehicle speed sensor 13 is attached to the body of the host vehicle, for example, and detects the vehicle speed of the host vehicle. The vehicle speed sensor 13 transmits the detected vehicle speed to the recognition unit 2.

  The recognizing unit 2 performs image processing on the image transmitted from the CCD camera 12, thereby recognizing a white line drawn on the road, an obstacle on the road, and a preceding vehicle serving as a target object. The recognizing unit 2 recognizes the preceding vehicle, thereby confirming that the actual inter-vehicle distance transmitted from the distance sensor 11 is the actual inter-vehicle distance with respect to the preceding vehicle and confirming the target acceleration for tracking in the target acceleration candidate calculating unit 3. This is transmitted to the steady running state target acceleration calculation unit 21 and the deceleration timing determination target acceleration calculation unit 22 of the calculation unit 20, respectively. Furthermore, the recognition unit 2 transmits the vehicle speed transmitted from the vehicle speed sensor 13 to the steady travel state target acceleration calculation unit 21 and the deceleration timing determination target acceleration calculation unit 22, respectively.

  The steady running state target acceleration calculation unit 21 stores a target inter-vehicle time ht used when calculating the target inter-vehicle distance, and the following (1) is determined based on the target inter-vehicle time ht and the own vehicle speed transmitted from the recognition unit 2. ) The target inter-vehicle distance AL is calculated based on the equation.

AL = ht * V (1)
The steady running state target acceleration calculation unit 21 stores control gains K1 and K2 for calculating the target acceleration, and the calculated target inter-vehicle distance AL and the preceding positional relationship that is transmitted from the recognition unit 2. The steady state target acceleration at1 is calculated based on the following equation (2) using the inter-vehicle distance L with respect to the vehicle, the relative speed VR, and the stored control gains K1 and K2.

at1 = K1 (L-AL) + K2 * VR (2)
The steady running state target acceleration calculation unit 21 transmits the steady state target acceleration at1 calculated based on the equation (2) to the selection unit 23.

The target acceleration calculation unit 22 for determining the deceleration timing is used when the preceding vehicle is located far away. The target acceleration calculating unit 22 is a target acceleration for quickly entering the deceleration operation when the user wants to decelerate while approaching the preceding vehicle as soon as possible. A certain target acceleration at2 for determining the deceleration timing is calculated. In order to calculate the deceleration timing determination target acceleration at2, the deceleration timing determination target acceleration calculation unit 22 includes a preset speed control pattern and a deceleration timing determination that is the maximum value of the deceleration timing determination target acceleration at2. The target acceleration maximum value at2_MAX is stored. The deceleration timing determination target acceleration maximum value at2_MAX may be any value as long as it is definitely larger than the steady-state target acceleration at1 and cannot be adopted, and is set to 10G, for example.

  As a speed control pattern here, a pattern in which the vehicle is decelerated at a constant acceleration is set, and the relative speed between the preceding vehicle and the host vehicle is VR, the acceleration of the host vehicle is a, and the time is t. The formula holds.

VR = a * t (3)
^{L-AL = at 2/2} ··· (4)
When the time t is deleted from the above equations (3) and (4) and the acceleration a is used, the following equation (5) is obtained, and this acceleration a can be used as the target acceleration at2_tmp for temporary deceleration timing determination. This temporary deceleration timing determination target acceleration at2_tmp is a speed control amount pattern until the relative positional relationship between the preceding vehicle and the host vehicle satisfies the target relative positional relationship.

at2_tmp =-(VR * VR) / 2 * (L-AL) (5)
Further, the deceleration timing determination target acceleration calculation unit 22 stores, for example, −0.1 G as a threshold value as to whether or not the temporary acceleration timing determination target acceleration at2_tmp is adopted as the target acceleration. When the target acceleration at2_tmp for temporary deceleration timing determination is equal to or greater than −0.1 G, the target acceleration maximum value at2_MAX for deceleration timing determination is employed as the target acceleration at2 for deceleration timing determination. When the target acceleration at2_tmp for temporary deceleration timing determination is less than −0.1 G, the target acceleration at2_tmp for temporary deceleration timing determination is adopted as the target acceleration at2 for deceleration timing determination. The deceleration timing determination target acceleration calculation unit 22 transmits the deceleration timing determination target acceleration at2 thus calculated to the selection unit 23.

  The selection unit 23 compares the steady state target acceleration at1 transmitted from the steady running state target acceleration calculation unit 21 with the deceleration timing determination target acceleration at2 transmitted from the deceleration timing determination target acceleration calculation unit 22. Then, the smaller one of the steady-state target acceleration at 1 and the deceleration timing determination target acceleration at 2 is selected as the tracking target acceleration and transmitted to the arbitration unit 4.

  The constant speed target acceleration calculation unit 30 calculates the target acceleration of the host vehicle when there is no preceding vehicle as a target object, and transmits the calculated target acceleration to the arbitration unit 4. Further, the corner acceleration prohibition target acceleration calculation unit 40 calculates the target acceleration of the host vehicle when the host vehicle is on a curve, and transmits the calculated target acceleration to the arbitration unit 4.

  The arbitration unit 4 performs arbitration among the three target accelerations transmitted from the following target acceleration calculation unit 20, the constant speed target acceleration calculation unit 30, and the corner acceleration prohibition target acceleration calculation unit 40, and finally To determine the target acceleration. The target acceleration determined in this way is transmitted to the change rate limiting unit 5.

  In this embodiment, the target acceleration calculation unit 20 for tracking, the target acceleration calculation unit 30 for constant speed, and the target acceleration calculation unit 40 for corner acceleration prohibition always calculate the target acceleration, and the arbitration unit 4 Of the plurality of target accelerations, the minimum value is determined as the target acceleration. However, the present invention is not limited to this, and the arbitration unit 4 selects one of a plurality of calculated target accelerations as the target acceleration based on the relationship between the preceding vehicle and the host vehicle, The acceleration may be determined, or a value obtained by taking a weighted average of each acceleration may be determined as the target acceleration.

  The change rate limiting unit 5 stores a predetermined limit value for the acceleration change rate of the host vehicle. The change rate limiting unit 5 compares the target acceleration transmitted from the arbitration unit 4 with the stored limit value, and when the change rate of acceleration does not exceed the limit value, the target rate transmitted from the arbitration unit 4 The acceleration is adopted as the target acceleration as it is. When the target acceleration transmitted from the arbitration unit 4 exceeds the limit value, the limit value is adopted as the target acceleration.

  The change rate limiting unit 5 transmits the adopted target acceleration to the actuator selection unit 14. The actuator selection unit 14 is connected to an engine control device and a brake control device (not shown). When the adopted target acceleration is positive, the actuator selection unit 14 transmits the target acceleration to the engine control device. The target acceleration is transmitted to the control device. The engine control device and the brake control device respectively control the engine and the brake so as to achieve the transmitted target acceleration.

  Next, a procedure for traveling control by the traveling control apparatus according to the present embodiment will be described. FIG. 3 is a flowchart showing a procedure of travel control according to the present embodiment. Here, a control procedure in the target acceleration calculation unit 20 for tracking, which is a characteristic part of the present embodiment, will be described.

  As shown in FIG. 3, in the travel control according to the present embodiment, first, the steady state target acceleration at1 is calculated in the steady state target acceleration calculation unit 21 (S1). The steady state target acceleration at1 is calculated based on the above equation (2). The steady running state target acceleration calculation unit 21 transmits the calculated steady state target acceleration at1 to the selection unit 23. Next, the deceleration timing determination target acceleration calculation unit 22 calculates the deceleration timing determination target acceleration at2. In order to calculate the target acceleration at2 for determining the deceleration timing, the target acceleration calculating unit 22 for determining the deceleration timing first determines that the preceding vehicle is faster than the own vehicle and the relative speed of the preceding vehicle with respect to the own vehicle is less than zero. It is determined whether or not (S2).

  As a result, when it is determined that the relative speed is not less than 0, the deceleration timing determination target acceleration at2 is set to the deceleration timing determination target acceleration maximum value at2_MAX (S6). If the relative speed is not less than 0, the host vehicle does not need to be decelerated, so the deceleration timing determination target acceleration is set to the deceleration timing determination target acceleration maximum value at2_MAX. Thus, the target acceleration at2 for determining the deceleration timing is not selected in the subsequent minimum value selection.

  On the other hand, if it is determined that the relative speed is less than 0, a temporary acceleration timing determination target acceleration at2_tmp is calculated (S3). The target acceleration at2_tmp for temporary deceleration timing determination is calculated based on the above equation (5). After calculating the temporary acceleration timing determination target acceleration at2_tmp, it is determined whether or not the temporary deceleration timing determination target acceleration at2_tmp is less than a predetermined threshold value of −0.1 G (S4).

  As a result, if it is determined that the target acceleration at2_tmp for determining the temporary deceleration timing is not less than −0.1 G, it is considered that there is no sudden deceleration, so the target acceleration at2 for determining the deceleration timing is used for determining the deceleration timing. The target acceleration maximum value at2_MAX is set (S6). Thus, the target acceleration at2 for determining the deceleration timing is not selected in the subsequent minimum value selection.

  On the other hand, when it is determined that the target acceleration at2_tmp for determining the temporary deceleration timing is less than −0.1 G, the host vehicle approaches the preceding vehicle and is in a state of starting deceleration. At this time, in order to speed up the deceleration of the host vehicle, the calculated temporary acceleration timing determination target acceleration at2_tmp is adopted as the deceleration timing determination target acceleration at2 (S5). Thus, the target acceleration at2 for determining the deceleration timing is set.

  As described above, when the target acceleration at2_tmp for determining the temporary deceleration timing is less than the threshold, the target acceleration for determining the temporary deceleration timing at2_tmp is set as the target acceleration for determining the deceleration timing. By using the target acceleration maximum value at2_MAX, the deceleration timing determination target acceleration at2 is not selected when unnecessary.

  FIG. 4A shows an example of the change over time in the target acceleration when the target acceleration at2_tmp for temporary deceleration timing determination is always set as the target acceleration for deceleration timing determination. Further, in the case where the relationship between the preceding vehicle and the host vehicle is the same, the time-dependent change in the target acceleration at2 for determining the deceleration timing when the threshold value (−0.1 G) is set for the target acceleration at2_tmp for determining the temporary deceleration timing is illustrated. Shown in 4 (b).

  As can be seen from FIG. 4, when the threshold value is provided for the provisional deceleration timing determination target acceleration at2_tmp and the case where no threshold value is provided, the target acceleration starts to decrease at an early stage. From this, the deceleration of the host vehicle can be quickly started before the distance between the preceding vehicle and the host vehicle is greatly reduced.

  In addition, when a threshold value is set in the target acceleration at2_tmp for temporary deceleration timing determination shown in FIG. 4B, the deceleration of the host vehicle can be started quickly, so that the deceleration of the host vehicle can be reduced. Deceleration can be avoided.

  In this way, when the steady state target acceleration at1 and the deceleration timing determination target acceleration at2 are calculated in step S1, step S5, and step S6 and transmitted to the selection unit 23, the selection unit 23 determines that the steady state target acceleration at1 is the deceleration timing. It is determined whether or not the target acceleration for determination at2 or less (S7). As a result, when it is determined that the steady state target acceleration at1 is equal to or less than the deceleration timing determination target acceleration at2, the steady state target acceleration at1 is selected as the target acceleration (S8). On the other hand, when it is determined that the steady-state target acceleration at1 exceeds the deceleration timing determination target acceleration at2, and is not less than or equal to the deceleration timing determination target acceleration at2, the deceleration timing determination target acceleration at2 is selected as the target acceleration. (S9). The selection unit 23 determines the selected target acceleration (S10) and transmits it to the arbitration unit 4.

  Next, a modified example of the present invention will be described. This modification mainly differs from the above-described embodiment in the configuration of the tracking target acceleration calculation unit 20. FIG. 5 is a block diagram of a tracking target acceleration calculation unit according to the present modification.

  As shown in FIG. 5, the target acceleration calculation unit 20 for tracking according to this modification includes a steady running state target acceleration calculation unit 21, a deceleration timing determination target acceleration calculation unit 22, and a selection unit similar to those in the above embodiment. 23 is provided. Further, the follow-up target acceleration calculation unit 20 according to this modification includes a preceding vehicle approach target acceleration calculation unit 24, a stop target acceleration calculation unit 25, a catch-up acceleration limiting unit 26, and a stop holding target acceleration calculation unit 27. Is provided.

  The preceding vehicle approach target acceleration calculation unit 24 calculates a target acceleration for decelerating the host vehicle when the preceding vehicle approaches the host vehicle. The target acceleration calculation unit for stop 25 calculates a target acceleration for stopping the host vehicle while preventing a decrease in ride comfort of the occupant when the preceding vehicle stops. The catch-up acceleration limiting unit 26 calculates a target acceleration when the preceding vehicle is traveling at a low speed or stopped at a position far from the host vehicle. The stop-holding target acceleration calculation unit 27 calculates the target acceleration so as to continue the stop state when the vehicle is stopped with the actual inter-vehicle distance being larger than the target inter-vehicle distance.

  The preceding vehicle approach target acceleration calculation unit 24, the stop target acceleration calculation unit 25, the catch-up acceleration limiting unit 26, and the stop holding target acceleration calculation unit 27 transmit the calculated target accelerations to the selection unit 23, respectively. In the selection unit 23, a steady running state target acceleration calculation unit 21, a deceleration timing determination target acceleration calculation unit 22, a preceding vehicle approach target acceleration calculation unit 24, a stop target acceleration calculation unit 25, a catch-up acceleration limit unit 26, and a stop The target accelerations transmitted from the holding target acceleration calculation unit 27 are compared, and the smallest target acceleration is selected. Then, the selected target acceleration is transmitted to the arbitration unit 4.

  In this way, the target acceleration is calculated not only in the steady running state target acceleration calculation unit 21 and the deceleration timing determination target acceleration calculation unit 22 but also in other modes, and the calculated target values are calculated. It is also possible to select a minimum target acceleration from the accelerations.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, in the above embodiment, the speed control amount is set from the calculated target acceleration. However, for example, the target speed can be directly calculated or set from the target driving force control amount. In the above embodiment, the target inter-vehicle distance is used as the target relative relationship with the target object, but the target inter-vehicle time or the target relative time can also be used. Furthermore, although the above embodiment shows an example in which the host vehicle travels while decelerating at a constant acceleration as a speed control pattern, other speed control patterns may be used.

  Furthermore, in the above embodiment, when the relative speed of the preceding vehicle with respect to the host vehicle is less than 0, or when the target acceleration at2_tmp for temporary deceleration timing determination is equal to or greater than −0.1 G, which is a predetermined threshold value, The target acceleration for determination of deceleration timing is set to the maximum target acceleration for determination of deceleration timing at2_MAX. Instead, when the relative speed of the preceding vehicle with respect to the host vehicle is less than 0, or when the target acceleration at2_tmp for temporary deceleration timing determination is −0.1 G which is a predetermined threshold value, the deceleration timing determination is performed. The selection unit 23 may always select the steady-state target acceleration at1 without calculating the target acceleration at2.

  In the present invention, when the relative speed of the preceding vehicle with respect to the host vehicle is less than 0, the target acceleration for deceleration timing determination is set to at2_MAX. However, the present invention is not limited to this, and the relative speed is set from 0. The determination may be made as a large predetermined number, or the relative speed of the preceding vehicle relative to the host vehicle may not be determined.

1 is a block configuration diagram of a vehicle travel control device according to the present invention. FIG. It is a block block diagram of the target acceleration calculating part for tracking. It is a flowchart which shows the procedure of traveling control. (A) is a graph showing the change over time in the target acceleration when the target acceleration for determining the temporary deceleration timing at2_tmp is always set as the target acceleration for determining the deceleration timing, and (b) is a threshold set for the target acceleration for determining the temporary deceleration timing. It is a graph which shows the time-dependent change of the target acceleration for deceleration timing judgment in this case. It is a block block diagram of the target acceleration calculating part for tracking which concerns on a modification.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Target acceleration calculating part, 2 ... Recognition part, 3 ... Target acceleration candidate calculating part, 4 ... Arbitration part, 5 ... Change rate limiting part, 11 ... Distance sensor, 12 ... Camera, 13 ... Vehicle speed sensor, 14 ... Actuator selection , 20 ... tracking target acceleration calculation unit, 21 ... steady-running state target acceleration calculation unit, 22 ... deceleration acceleration determination target acceleration calculation unit, 23 ... selection unit, 24 ... preceding vehicle approach target acceleration calculation unit, 25 ... Stop target acceleration calculation unit, 26 ... Acceleration limiting unit, 27 ... Stop / hold target acceleration calculation unit, 30 ... Constant speed target acceleration calculation unit, 40 ... Corner acceleration prohibition target acceleration calculation unit, AL ... Target inter-vehicle distance, at1 ... steady state target acceleration, at2 ... target acceleration for determining deceleration timing, at2_MAX ... maximum target acceleration for determining deceleration timing, at2_tmp ... for determining temporary deceleration timing Target acceleration.

Claims (3)

In the vehicular travel control apparatus that controls the braking / driving force so that the relative positional relationship with the target object detected by the object detection means becomes the set target relative positional relationship,
First calculation means for calculating a first target acceleration based on a deviation and a relative speed between the target relative positional relationship and the relative positional relationship;
A state in which a calculated target acceleration is calculated based on a deviation between the target relative position relationship and the relative position relationship and a preset target acceleration pattern, and the calculated target acceleration causes a preset sudden deceleration. A second calculation means for setting the calculated target acceleration to a second target acceleration when the calculated target acceleration is less than a reference value,
A vehicle travel control device that controls braking / driving force of a vehicle based on a minimum value of a first target acceleration and a second target acceleration.   The second calculation means uses the preset target acceleration maximum value as the second target acceleration when the calculated target acceleration is equal to or greater than a reference value indicating whether or not a preset sudden deceleration occurs. The vehicle travel control device according to claim 1. The second calculation means calculates a target acceleration when the target relative position relationship is reached at a constant deceleration based on the current relative position relationship and relative speed as the calculated target acceleration. The vehicle travel control device described.

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