JP2006163615A - Vehicle speed detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle speed detecting device capable of making speeds to be reference between respective vehicles coincide with each other at the time of traveling in line. <P>SOLUTION: A radar device, a front camera 2 and an image processor 21 calculate a distance to the preceding vehicle and relative speed information, and a control ECU 5 calculates or corrects the current speed of a self-vehicle on the basis of the distance, the relative speed information and speed information of the preceding vehicle received by communication equipment 40. By using the speed information calculated in this way to travel in line, reference speeds in a traveling group in line coincide with each other so that the vehicle can travel in an orderly manner. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a speed detection device mounted on a vehicle, and more particularly to a speed detection device mounted on each vehicle when traveling according to the flow of the vehicle.

  In order to improve safety on highways, reduce the burden on drivers, and improve traffic efficiency, a technology that enables platooning in which a large number of unconnected vehicles run orderly at approximately the same speed has been proposed. (For example, refer to Patent Document 1).

In such platooning, a system has been proposed that eliminates the need for special infrastructure by using automatic traveling control that controls the vehicle speed and the distance between the vehicles to follow the preceding vehicle. However, there are individual differences in the speed sensor of each vehicle, and even if the upper limit speed at the time of automatic driving is set to be the same, there is a possibility that the actual speed can be different due to the individual difference and the formation may be disturbed. . In order to solve such problems, the technique of Patent Document 1 sets the upper limit speed during platooning higher than that during normal follow-up running.
JP 2003-317199 A

  However, even if the upper limit speed is set higher than that during normal follow-up running, the problem cannot be solved as long as a difference in actual realizable speed can occur. For example, consider the case where the speedometer of the preceding vehicle shows a lower value than the speedometer of the following vehicle even at the same vehicle speed. Referring to the value of the speedometer, the upper limit speed that can be achieved with the preceding vehicle exceeds the upper limit speed that can be achieved with the following vehicle. As a result, if the distance between the preceding vehicle and the preceding vehicle is open, the preceding vehicle accelerates to its upper limit speed, which exceeds the upper limit speed of the following vehicle, so the following vehicle reduces the inter-vehicle distance. I can't do that, and I'm confused. This is established between any two front and rear vehicles in the platoon, so if there is a vehicle in the platoon that determines that the vehicle speed is faster than the other vehicle even if the actual vehicle speed is the same as the other vehicle, It will end up.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle speed detection device that makes it possible to match the reference speed of each vehicle when traveling in accordance with the flow of the vehicle such as platooning.

  In order to solve the above-mentioned problems, a vehicle speed detection device according to the present invention is a speed detection device mounted on a vehicle, and receives means for detecting a distance between the vehicle and a reference vehicle, and speed information of the reference vehicle. The communication means, and a means for calibrating the speed information of the host vehicle based on the inter-vehicle distance from the reference vehicle, the speed information of the reference vehicle, and the detected host vehicle speed.

  Examples of means for independently detecting the speed of the host vehicle include a vehicle speed sensor and a wheel speed sensor. Examples of means for detecting the inter-vehicle distance from the reference vehicle include a radar device and an image recognition means. As a communication means for receiving the speed information of the reference vehicle, there is an inter-vehicle communication device. Since the relative distance to the reference vehicle changes according to the speed of the reference vehicle and the speed of the host vehicle, the speed information of the host vehicle can be calibrated by verifying the consistency between the information. it can.

  For example, when the inter-vehicle distance from the reference vehicle is constant for a predetermined time or more, it is considered that the vehicle speed of the reference vehicle and the vehicle speed of the host vehicle are substantially matched. Therefore, the reference vehicle speed may be set to the speed of the host vehicle.

  Alternatively, the vehicle speed detection device according to the present invention is a speed detection device mounted on a vehicle that performs platooning, and includes means for detecting a relative speed with respect to a reference vehicle and communication for receiving speed information of the reference vehicle. And means for calculating relative speed information with respect to the reference vehicle and speed information of the host vehicle based on the speed information of the reference vehicle.

  The relative speed between the reference vehicle and the own vehicle is a difference between the vehicle speed of the reference vehicle and the own vehicle. This relative speed is obtained, for example, by differentiating the inter-vehicle distance with respect to time. That is, the vehicle speed of the host vehicle can be obtained from the relative speed and the vehicle speed of the reference vehicle, and thereby the speed information of the host vehicle can be calculated or calibrated. For example, the reference vehicle may be a preceding vehicle that travels immediately before the host vehicle.

  According to the present invention, (1) the reference vehicle speed information and relative speed information, or (2) the reference vehicle speed information and own vehicle speed information, and the inter-vehicle distance between the reference vehicle and the own vehicle are used. Vehicle speed can be verified and calibrated. For this reason, it becomes possible to travel in an orderly manner without variations in the speed detection devices of the vehicles in the platoon. Furthermore, the error between the vehicles after calibration can be made smaller than when the speed detection device is individually inspected and calibrated, and stable platooning is possible.

  By using the speed information of the reference vehicle as a reference, the setting can be facilitated and the influence of the error of the speed detection device of the host vehicle can be eliminated. Further, when the reference vehicle is a preceding vehicle, it is easy and reliable to acquire relative speed information and inter-vehicle distance information.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same reference numerals are given to the same components in the drawings as much as possible, and duplicate descriptions are omitted.

  FIG. 1 is a block diagram of a vehicle equipped with a vehicle speed detection device according to the present invention. In the host vehicle M, the radar device 1 for acquiring the position and distance information of the preceding vehicle, the front camera 20 for acquiring the front image of the vehicle, and the image for acquiring the preceding vehicle information by image recognition from the acquired image of the front camera 20 A processing device 21, a vehicle speed sensor 3 for detecting the vehicle speed, a communication device 40 and an antenna 41 for performing inter-vehicle communication with other vehicles, and a control ECU 5 for performing vehicle speed control during platooning. Each output is input to the control ECU 5 from the radar device 1, the image processing device 21, the vehicle speed sensor 3, and the communication device 40, and the vehicle speed of the host vehicle is controlled in cooperation with the brake ECU 6 and the engine ECU 7. The control ECU 5 includes a CPU, a ROM, a RAM, and the like, and also serves as a calibration unit for the speed detection device according to the present invention.

Next, the row running by the control ECU 5 will be described. FIG. 2 is a diagram for explaining the situation of the row running. In this platooning, the preceding vehicle P is detected by the radar device 1 and the image processing device 21, and the inter-vehicle distance Dr between the host vehicle M and the preceding vehicle P is substantially matched with the target distance Dt, and the inter-vehicle distance condition is satisfied. If it has is to realize a row running traveling orderly keeping the inter-vehicle distance each vehicle is set at the same speed in the convoy by maintaining the vehicle speed V _M to the target vehicle speed Vt.

When the inter-vehicle distance Dr is open than the target distance Dt is the engine ECU 7, by accelerating from Vt range by controlling a drive system (not shown) the vehicle speed V _M equal to or smaller than the upper limit vehicle speed Vlimit1, Reduce the inter-vehicle distance Dr. On the other hand, when the inter-vehicle distance Dr is clogged than the target distance Dt is the engine ECU 7, by decelerating from Vt control to the host vehicle speed V _M of the drive system, not shown, opens the inter-vehicle distance Dr. When the control ECU 5 determines that the deceleration is insufficient, the engine ECU is braked by downshifting, or the brake ECU 6 is controlled to operate the braking system to quickly decelerate.

  In order to stably realize the platooning, it is necessary that the vehicle speeds of the vehicles in the platoon coincide with each other with high accuracy. The vehicle speed detection device according to the present invention has a function of verifying vehicle speed information of the vehicle speed sensor 3. Hereinafter, this verification method will be specifically described.

FIG. 3 is a flowchart of this verification process. This verification process is executed by the control ECU 5. First, obtain a vehicle speed information _{V M} of the vehicle from the vehicle speed sensor 3 (step S1). Next, to obtain the velocity information _{V P} of the preceding vehicle P to the communication device 40 via the antenna 41 is received (step S2). Next, the distance information Dr between the preceding vehicle P is obtained from the outputs of the radar device 1 and the image processing device 21 (step S3). The position information of the obstacle ahead of the vehicle can be determined by only one of the radar device 1 and the image processing device 21, but the lane information is extracted by the image processing device 21, and the object detected by the radar device 1 is this. By verifying that the vehicle is in the lane, the preceding vehicle can be reliably determined. It is also possible to make a determination using only one of them.

  Then, Dr is compared with the value of Drold, which is the distance information value at the previous time step (step S4), and when the absolute value of the difference is within the threshold ΔDrth, 1 is added to the counter value i (step S5). ), It is determined whether the value of the counter value i exceeds the threshold value ith (step S6).

If the value of the counter value i is determined to exceed the threshold value ith, the process proceeds to step S7, the vehicle speed difference of the preceding vehicle P and the vehicle M (relative speed) ΔV (= V _P -V _M ) And a calibration value V _M ′ of the speed V _M of the host vehicle is obtained by the formula V _M ′ = V _M + ΔV (step S8).

  If it is determined in step S4 that the distance is changing, i is reset to 0 (step S9), and the process directly proceeds to step S8. Similarly, when it is determined in step S6 that the counter value i is within the threshold value ith, the process directly proceeds to step S8.

  Thereby, the reference | standard of the vehicle speed information of the preceding vehicle P and the vehicle speed information of the own vehicle M can be matched. Similarly, by repeating this between the preceding vehicle and the following vehicle, it is possible to achieve consistency in vehicle speed within the platooning group, and to perform platooning in an orderly manner.

  FIG. 4 is a flowchart illustrating another example of the verification process. This verification process is also executed by the control ECU 5 similarly to the verification process shown in FIG. The processing in steps S1 to S3 is the same as the verification processing shown in FIG. Then, the relative speed ΔV between the preceding vehicle P and the host vehicle M is calculated based on the time change amount of the distance information (step S14). ΔV can also be obtained by utilizing the fact that the frequency changes due to the Doppler effect when the radar wave emitted from the radar apparatus collides with the preceding vehicle and is reflected. Next, ΔV is compared with the value of ΔVold, which is the distance information value at the previous time step (step S15). If the absolute value of the difference is within the threshold value ΔVth, 1 is added to the counter value i (step S15). S16) It is determined whether the value of the counter value i exceeds the threshold value ith (step S17).

If it is determined that the value of the counter value i exceeds the threshold value ith, the process proceeds to step S18, and the calibration value V _M ′ of the speed V _M of the host vehicle is expressed by the formula V _M ′ = V _P + ΔV. By Then, seeking _{V M} 'difference between _{V M ΔV M (= V M} ' -V M) ( step S19), and ends the process. This ΔV _M is the correction value.

If it is determined in step S14 that the amount of change in the relative speed is large, i is reset to 0 (step S20), and the calibration value V _M ′ is obtained from V _M + ΔV _M (step S21). Similarly, when it is determined in step S17 that the value of the counter value i is within the threshold value ith, the process directly proceeds to step S21.

Here, the correction value is defined as the difference between the calibration value and the calculated value obtained from the output of the vehicle speed sensor 3. However, depending on the characteristics of the vehicle speed sensor 3, a ratio between the calibration value and the calculated value is used, or a predetermined value is calculated from the calculated value. The error correction may be performed using the function. Further, the correction value may be set as the learning value for each V _M.

  Thus, by setting the own vehicle speed using the relative speed information and the vehicle speed information of the preceding vehicle, regardless of the error of the vehicle speed sensor 3 of the own vehicle M and the deviation from the speed detection device of the preceding vehicle P, It is easy to achieve consistency with the speed information of the preceding vehicle P. Similarly, by repeating this between the preceding vehicle and the following vehicle, it is possible to achieve consistency in vehicle speed within the platooning group, and to perform platooning in an orderly manner.

  In the above description, the example in which the vehicle speed used for the running control of the platooning is adjusted has been described. However, the display value itself of the speedometer that displays the vehicle speed to the driver may be changed according to this adjustment. By combining the display value of the speedometer and the vehicle speed used for traveling control, it is possible to reduce the uncomfortable feeling that the driver feels regarding the display speed. In addition, although the example in which the vehicle speed is adjusted using the preceding vehicle as the reference vehicle has been described here, the reference vehicle is not limited to the immediately preceding preceding vehicle, but two or more preceding vehicles, following vehicles, or parallel running Even a vehicle or the like can be adjusted as long as the relative speed and the traveling direction component of the distance between the vehicles can be determined. For example, in the case of platooning, one or several specific vehicles in a group may be used as reference vehicles for other vehicles, and when there are several reference vehicles, each except one What is necessary is just to set the reference | standard vehicle with respect to each with respect to a reference | standard vehicle.

  In addition, the speed detection device for a vehicle according to the present invention can calibrate the speed detection device not only during platooning. For example, the vehicle speed can be matched between the vehicles when traveling according to the flow of the vehicle, such as matching the vehicle speed between the following vehicle and the preceding vehicle during the following traveling. Further, as shown in FIG. 5, the vehicle speed measuring means 8 having a communication device arranged on the road or on the road side receives the measured vehicle speed information of the own vehicle M through the communication device 40, and It is also possible to calibrate the vehicle speed detection device.

1 is a block configuration diagram of a vehicle equipped with a vehicle speed detection device according to the present invention. It is a figure explaining the condition of formation running. It is a flowchart of the verification process of the speed detection apparatus shown by FIG. It is a flowchart which shows another process example of a verification process. It is a figure explaining another example of the vehicle speed calibration by the vehicle speed detection apparatus concerning this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Radar device, 3 ... Vehicle speed sensor, 5 ... Control ECU, 6 ... Brake ECU, 7 ... Engine ECU, 8 ... Vehicle speed measuring means, 20 ... Front camera, 21 ... Image processing device, 40 ... Communication device, 41 ... Antenna .

Claims (4)

A speed detection device mounted on a vehicle,
Means for independently detecting the speed of the vehicle;
Means for detecting an inter-vehicle distance from a reference vehicle;
Communication means for receiving reference vehicle speed information;
Means for calibrating the speed information of the host vehicle based on the distance between the reference vehicle, the speed information of the reference vehicle, and the detected host vehicle speed;
A vehicle speed detection apparatus comprising:   The vehicle speed detection device according to claim 1, wherein when the inter-vehicle distance from the reference vehicle is constant for a predetermined time or more, the received reference vehicle speed is set as the speed of the host vehicle. A speed detection device mounted on a vehicle,
Means for detecting relative speed with respect to the reference vehicle;
Communication means for receiving reference vehicle speed information;
Means for calculating the speed information of the host vehicle based on the relative speed information with respect to the reference vehicle and the speed information of the reference vehicle;
A vehicle speed detection apparatus comprising:   The vehicle speed detection device according to any one of claims 1 to 3, wherein the reference vehicle is a preceding vehicle that travels immediately before the host vehicle.

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