JP6480101B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a technique for controlling a vehicle.

  In the inter-vehicle distance control (Adaptive Cruise Control: ACC), a radar mounted in front of the vehicle is used to maintain a constant inter-vehicle distance from the vehicle traveling ahead and to warn the driver as necessary.

  In the pre-crash safety system, the vehicle detects an obstacle and prepares for a collision. Computers analyze information from radars and cameras mounted on the vehicle, and give warnings to drivers and assist brakes.

  With regard to ACC, a technique is known that increases the accuracy of specifying the existence probability that another vehicle traveling ahead of the host vehicle is on the same lane as the host vehicle (see, for example, Patent Document 1).

JP 2007-331608 A

  In the ACC, the radio wave transmitted from the radar is reflected by a vehicle traveling in front, and the vehicle traveling in front is detected by receiving the reflected radio wave.

  However, especially when a millimeter wave radar is used, the received power of the radio wave reflected by the vehicle traveling in front of the millimeter wave may be reduced due to the influence of the multipath due to the road surface or the like. When the reception power of the radio wave reflected by the vehicle traveling ahead decreases, the vehicle traveling ahead may not be detected depending on the degree of decrease in the reception power. That is, when the reception power of the radio wave reflected by the vehicle traveling ahead decreases, the vehicle ahead may not be detected for a moment and may be lost. In ACC, when a vehicle ahead cannot be detected, it is assumed that there is no vehicle ahead and acceleration is performed. After acceleration, if the vehicle ahead is detected due to a change in radio waves reflected by the vehicle traveling ahead, the vehicle decelerates.

  In other words, when losing sight of the vehicle ahead, the ACC accelerates and decelerates the vehicle unnecessarily, resulting in poor followability to the vehicle ahead.

  An object of the present invention is to improve followability in inter-vehicle distance control.

A vehicle control device according to an embodiment of the disclosure is:
A vehicle control device mounted on a vehicle,
Detecting means for detecting a target in front of the vehicle;
Lane presence probability calculating means for calculating the own lane probability as the probability that the target detected by the detection means exists in the same lane as the lane in which the vehicle is traveling,
A first selection means for selecting a target having a relatively high own lane probability as a target to be controlled of the inter-vehicle distance from the targets detected by the detection means;
A second selection means for selecting a target having a relatively high own lane probability as a target for collision prevention control from among the targets detected by the detection means;
Distance control means for controlling the inter-vehicle distance between the target selected by the first selection means;
Anti-collision control means for performing anti-collision control with the target selected by the second selection means;
Correction means for correcting the current own lane probability calculated by the lane presence probability calculating means for each target detected by the detecting means based on the past own lane probability; and
The first selection unit selects a target to be controlled by the inter-vehicle distance from the targets detected by the detection unit based on the own lane probability corrected by the correction unit,
The second selecting means is the detecting means based on the own lane probability calculated by the lane existence probability calculating means and not corrected based on the past own lane probability. The target to be subjected to the collision prevention control is selected from the targets detected by the above.

  According to the disclosed embodiment, it is possible to improve follow-up performance in inter-vehicle distance control.

It is a figure which shows inter-vehicle distance control. It is a figure which shows one Example of a vehicle control apparatus. It is a flowchart which shows one Example of operation | movement of a vehicle control apparatus. It is a figure which shows an example of a time-dependent change of the preceding vehicle number (No.) of the target made into ACC. It is a figure which shows an example of the time-dependent change of the horizontal position of the target of ACC. It is a figure which shows an example of the time-dependent change of the own lane probability of the target of ACC.

Next, the form for implementing this invention is demonstrated, referring drawings based on the following Examples. Examples described below are merely examples, and embodiments to which the present invention is applied are not limited to the following examples.
In all the drawings for explaining the embodiments, the same reference numerals are used for those having the same function, and repeated explanation is omitted.

<Example>
FIG. 1 is a diagram illustrating inter-vehicle distance control.

  FIG. 1 shows an ACC vehicle 10 that is equipped with a vehicle control device and performs inter-vehicle distance control (ACC) by the vehicle control device, and a preceding vehicle 20 that travels in front of the vehicle.

  The vehicle control device mounted on the ACC vehicle 10 controls the inter-vehicle distance from the preceding vehicle 20 using a radar mounted in front of the ACC vehicle 10.

<Vehicle control device>
FIG. 2 shows an embodiment of the vehicle control device.

  The vehicle control device includes a millimeter wave radar 200.

  The millimeter wave radar 200 includes a transmission / reception unit 202 and a signal processing unit 204.

  The transmission / reception unit 202 transmits a millimeter wave in front of the ACC vehicle 10 and receives a reflected wave generated when the millimeter wave is reflected by a target (target) located in front of the ACC vehicle 10. An example of a target located in front of the ACC vehicle 10 is a preceding vehicle 20. The transmission / reception unit 202 is configured to mechanically change the millimeter wave transmission direction in the vertical and horizontal directions.

  The transmitting / receiving unit 202 obtains a signal having a beat frequency (hereinafter referred to as “beat signal”) by mixing the reflected wave and the transmitted wave. The beat frequency is a distance R between the millimeter wave radar 200 and the target located in front of the ACC vehicle 10 and a relative velocity V between the millimeter wave radar 200 and the target located in front of the ACC vehicle 10. Proportional. The transmission / reception unit 202 inputs a beat signal to the signal processing unit 204.

  The signal processing unit 204 is connected to the transmission / reception unit 202. The signal processing unit 204 selects a target to be ACC based on the beat signal. For example, the transmission / reception unit 202 changes the millimeter wave transmission direction, and selects a target to be ACC based on sampling data obtained by sampling a beat signal obtained by the transmission / reception unit 202. One or more targets may be targeted for ACC. One example of a target to be ACC is a preceding vehicle 20.

  The signal processing unit 204 obtains preceding vehicle information for a target to be ACC. One example of the preceding vehicle information includes the distance and direction between the millimeter wave radar 200 and the preceding vehicle 20 positioned in front of the ACC vehicle 10, the speed of the preceding vehicle 20 positioned in front of the ACC vehicle 10, and the like. The speed of the preceding vehicle 20 located in front of the ACC vehicle 10 may be a relative speed of the ACC vehicle 10 with respect to the ACC vehicle 10. Based on the beat signal, the signal processing unit 204 calculates a frequency corresponding to the distance (hereinafter referred to as “distance frequency”) and a frequency corresponding to the relative speed (hereinafter referred to as “relative speed frequency”), and millimeter wave The distance between the radar 200 and the preceding vehicle 20 positioned in front of the ACC vehicle 10 and the relative speed of the ACC vehicle 10 with respect to the ACC vehicle 10 are obtained. The azimuth between the millimeter wave radar 200 and the preceding vehicle 20 located in front of the ACC vehicle 10 is obtained from a beat signal obtained by mechanically changing the millimeter wave transmission direction to the vertical direction and the horizontal direction. The signal processing unit 204 inputs the preceding vehicle information to the DSS ECU 100.

  Further, when the preceding vehicle number (No.) of the target to be ACC is input from the DSS ECU 100, the signal processing unit 204 selects the preceding vehicle number (No.) of the target to be ACC selected. It is determined whether or not it is included in the target ACC target. The signal processing unit 204 inputs, to the DSS ECU 100, a determination result as to whether the preceding vehicle number (No.) of the target to be ACC is included in the selected target to be ACC selected.

  The DSS ECU 100 is connected to the millimeter wave radar 200. The probability that the DSS ECU 100 selects a preceding vehicle 20 of the ACC vehicle 10 is traveling in the same lane as the ACC vehicle 10 (hereinafter also referred to as “own lane”). (Hereinafter referred to as “own lane probability”).

  For example, the DSS ECU 100 determines, based on the preceding vehicle information from the millimeter wave radar 200, the relative position of the preceding vehicle 20 that travels ahead of the ACC vehicle 10 that travels on one lane on the road with predetermined coordinates. Identified above. The DSS ECU 100 estimates the shape of the road on which the ACC vehicle travels. The DSS ECU 100 calculates the instantaneous value P_s of the own lane probability based on the relative position of the preceding vehicle, the road shape estimation result, and the like.

  The DSS ECU 100 calculates the instantaneous value P_s of the own lane probability regularly or irregularly, and the target for which the instantaneous value P_s of the own lane probability is calculated is determined as an ACC target identified by the preceding vehicle number (No.). It is judged whether it corresponds to the target to do.

  The DSS ECU 100 sets the time constant τ of the own lane probability when it is determined that the target for which the instantaneous value P_s of the own lane probability is calculated corresponds to the target for ACC specified by the preceding vehicle number (No.). If it is determined that the target for which the instantaneous value P_s of the own lane probability is calculated as τ_L does not correspond to the ACC target specified by the preceding vehicle number (No.), the time constant τ of the own lane probability is set Let τ_s. Here, τ_L> τ_s has a relationship of τ_L> τ_s and is preferably set in advance.

  The DSS ECU 100 calculates the current value P (t) of the own lane probability based on P_s (instantaneous value P (t) of the own lane probability), the past value of P (t), and τ. Here, the previous lane probability P (t−1) is used as the past value of P (t), and α (τ) and β (1-τ) are used as τ. It is possible to set as appropriate how many times the past value is used as the past value. Further, as the past value, a value obtained by statistical processing such as averaging past values may be used. For example, if the DSS ECU 100 determines that the target for which the instantaneous value P_s of the own lane probability is calculated includes the target to be ACC identified by the preceding vehicle number (No.), according to the equation (1), The current value of the own lane probability is calculated.

P (t) = α ₁ P (t-1) + β ₁ P (t) (1)
For example, when the DSS ECU 100 determines that there is no target for ACC identified by the preceding vehicle number (No.) in the target for which the instantaneous value P_s of the own lane probability is calculated, the equation (2) Therefore, the current value of the own lane probability is calculated.

P (t) = α ₂ P (t-1) + β ₂ P (t) (2)
In the expressions (1) and (2), α ₁ , α ₂ , β ₁ , β ₂ are weighting coefficients, and α ₁ + β ₁ = 1, α ₂ + β ₂ = 1, α ₂ <α ₁ , Β ₂ > β ₁ .

  The DSS ECU 100 sets the preceding vehicle number (No.) of the target to be ACC based on the current value of the own lane probability, and appropriately adjusts the inter-vehicle distance with the target to be ACC. Control information such as an acceleration request is input to an EFI ECU (Electronic Fuel Injection ECU) as a control command value. When the current value of the own lane probability is equal to or greater than a predetermined threshold (preceding vehicle recognition determination value), the DSS ECU 100 determines the preceding vehicle number (No. ) And create a control command value to properly adjust the distance between the target and the target ACC. The DSS ECU 100 inputs the preceding vehicle number (No.) of the target to be ACC targeted to the signal processing unit 204.

The EFI ECU 300 is connected to the DSS ECU 100. The EFI ECU 300 controls EFI and VSC (Vehicle Stability Control) in accordance with the acceleration request from the DSS ECU 100. The EFI ECU 300 is a control circuit mainly composed of a CPU, a ROM, a RAM, and the like.
The EFI ECU 300 is a variety of sensors mounted on the ACC vehicle 10 and sequentially measures the accelerator opening, the engine speed, the intake air amount, the air-fuel ratio in the exhaust pipe, and the like as measured values. On the other hand, the fuel injection amount is controlled. Each time the EFI ECU 300 measures the measurement value, the EFI ECU 300 generates at least engine speed information indicating the engine speed.

  The VSC sequentially measures the running speed of the ACC vehicle 10, the rotation speed of each tire, the torque, and the like as measured values. The VSC determines the degree of slipping on the road surface of the own ACC vehicle 10 based on the measured value, and controls the brakes of each tire based on the result of the determination, thereby causing the own ACC vehicle 10 to travel stably. .

<Operation of vehicle control device>
FIG. 3 shows an embodiment of the operation of the vehicle control device.

  In the embodiment of the operation of the vehicle control apparatus shown in FIG. 3, the preceding vehicle information is obtained by the millimeter wave radar 200, and the preceding vehicle number (No.) of the target to be ACC is input from the DSS ECU 100. Mainly shows the operation after it is determined whether or not the target for ACC identified by the preceding vehicle number (No.) corresponds to the target for ACC selected based on the beat signal. It is.

  In step S302, the DSS ECU 100 calculates an instantaneous value P_s of the own lane probability from the target position, the road shape estimation result, etc. for the target to be ACC.

  In step S304, the DSS ECU 100 determines whether or not the detected target target such as the target ACC corresponds to the target ACC target specified by the preceding vehicle number (No.) as the ACC control target. judge.

  In step S306, when it is determined that the target for ACC corresponds to the target for ACC specified by the preceding vehicle number (No.), the DSS ECU 100 sets the time constant τ of the own lane probability to τ_L. To do.

  In step S308, when it is determined that the target for ACC does not correspond to the target for ACC specified by the preceding vehicle number (No.), the DSS ECU 100 sets the time constant τ of the own lane probability to τ_s. Set.

  In step S310, the DSS ECU 100 calculates the current value P (t) of the own lane probability based on P_s, the past value of P (t), and τ.

  The right figure of step S310 shows the calculation result of the current value P (t) of the own lane probability.

  According to this figure, the P (t) _ACC control target represented by the solid line, that is, the target ACC target corresponding to the target ACC specified by the preceding vehicle number (No.) is P_s Even if it falls outside the target for ACC due to being smaller than the ACC determination threshold, the current value P (t) of the own lane probability is calculated based on the past values of P_s and P (t) and τ. Thus, it can be made larger than the ACC determination threshold. Since the current value P (t) of the own lane probability can be made larger than the ACC determination threshold, the target ACC target corresponding to the target ACC specified by the preceding vehicle number (No.) The frequency of deviating from the target object can be reduced.

  On the other hand, for P (t) _ACC controlled targets represented by broken lines, that is, for targets that do not fall under the target for ACC specified by the preceding vehicle number (No.), P_s is the ACC determination threshold. Even if it becomes smaller than the target for ACC by becoming smaller, it remains as it is.

  For targets that do not fall under the target for ACC specified by the preceding vehicle number (No.), the current value P (t) of the own lane probability is not calculated, and P_s is set to the ACC determination threshold. Since it becomes smaller than the target for ACC by making it smaller, the number of unnecessary operations can be reduced.

  After the process of step S310 is completed, the process returns to step S302.

  FIG. 4 shows the change over time of the preceding vehicle number (No.) of the target to be ACC set by the DSS ECU 100. In FIG. 4, the horizontal axis represents time [s], and the vertical axis represents the preceding vehicle number (No.) of the target to be ACCd. According to FIG. 4, it can be seen that the preceding vehicle No. 3 is selected as the preceding vehicle number (No.) of the target to be ACC. Also, according to FIG. 4, it can be seen that the preceding vehicle No. 3 is not selected for a time of about 0.15 s between 21 [s] and 22 [s]. That is, the preceding vehicle is deselected for a time of about 0.15 s between 21 [s] and 22 [s].

  FIG. 5 shows the change over time of the lateral position (lateral position) of the ACC target. In FIG. 5, the horizontal axis represents time [s], and the vertical axis represents the horizontal position [m], in other words, the horizontal position. According to FIG. 5, it can be seen that the lateral position of the target (preceding vehicle No. 3) to be ACC identified by the preceding vehicle number is approximately 1 [m]. Further, according to FIG. 5, it can be seen that the lateral position of the preceding vehicle No. 3 is 2 [m] or more for a time of about 0.15 s between 21 [s] and 22 [s].

  In this case, it is assumed that the preceding vehicle is traveling offset to the right by about 0.9 [m], which is the white line indicating the lane from the center of the lane. When the preceding vehicle travels in such a manner as being offset from the center of the lane, the preceding vehicle may be deselected.

  FIG. 6 shows a change with time of the own lane probability [%] of the target of the ACC selected by the DSS ECU 100. In FIG. 6, the horizontal axis represents time [s], and the vertical axis represents the own lane probability [%]. According to FIG. 6, it can be seen that as the target of the ACC, the time when the preceding lane probability of the preceding vehicle is 100 [%] is long. Moreover, according to FIG. 6, it turns out that the own lane probability has fallen for the time of about 0.15 s between 21 [s] -22 [s].

  According to one embodiment of the vehicle control device, the current own lane probability of the target to be ACC identified by the preceding vehicle number (No.) among the targets to be ACC is used as the past own lane probability. By correcting based on this, acceleration / deceleration due to ACC caused by losing sight of the vehicle ahead for a moment during ACC can be reduced. This is because this acceleration / deceleration is unnecessary control.

  In addition, for the target to be ACC, the current lane probability of the target to be ACC identified by the preceding vehicle number (No.) is corrected based on the past lane probability, for example, PCS (Pre For other targets such as -crash Safety System), the tracking performance in the inter-vehicle distance control can be improved without increasing the number of unnecessary operations by not correcting the own lane probability.

  In other words, by correcting one of the ACC target targets specified by the preceding lane number based on the previous lane probability, all the target lane probabilities are uniform. Compared with the case of correcting by applying the filter, it is possible to reduce unnecessary acceleration / deceleration due to ACC by losing sight of the vehicle ahead for a moment during ACC without increasing the number of unnecessary operations.

  Although the present invention has been described above with reference to specific embodiments and modifications, each embodiment and modification is merely illustrative, and those skilled in the art will recognize various modifications, modifications, alternatives, and substitutions. You will understand examples. For convenience of explanation, an apparatus according to an embodiment of the present invention has been described using a functional block diagram, but such an apparatus may be implemented in hardware, software, or a combination thereof. The present invention is not limited to the above-described embodiments, and various modifications, corrections, alternatives, substitutions, and the like are included without departing from the spirit of the present invention.

10 ACC vehicle 20 preceding vehicle 100 DSS ECU
200 Millimeter wave radar 202 Transmission / reception unit 204 Signal processing unit 300 EFI ECU

Claims (1)

A vehicle control device mounted on a vehicle,
Detecting means for detecting a target in front of the vehicle;
Lane presence probability calculating means for calculating the own lane probability as the probability that the target detected by the detection means exists in the same lane as the lane in which the vehicle is traveling,
A first selection means for selecting a target having a relatively high own lane probability as a target to be controlled of the inter-vehicle distance from the targets detected by the detection means;
A second selection means for selecting a target having a relatively high own lane probability as a target for collision prevention control from among the targets detected by the detection means;
Distance control means for controlling the inter-vehicle distance between the target selected by the first selection means;
Anti-collision control means for performing anti-collision control with the target selected by the second selection means;
Correction means for correcting the current own lane probability calculated by the lane presence probability calculating means for each target detected by the detecting means based on the past own lane probability; and
The first selection unit selects a target to be controlled by the inter-vehicle distance from the targets detected by the detection unit based on the own lane probability corrected by the correction unit,
The second selecting means is the detecting means based on the own lane probability calculated by the lane existence probability calculating means and not corrected based on the past own lane probability. Selecting a target to be subjected to the anti-collision control from the targets detected by
Vehicle control device.

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