JPH05256942A - Detecting apparatus of distance between vehicles - Google Patents

Abstract

PURPOSE:To calculate the distance between vehicles with high response and accuracy in a vehicle distance detecting apparatus even when the distance is suddenly changed by the interruption of another vehicle or the like. CONSTITUTION:The time series distance data from a laser radar device 10 is sequentially stored in a memory 12f in an ECU 12. An operating part 12d within the ECU 12 operates the weighted average of the time series distance data by weighting the same in the time series manner. The weighted average is set as the distance between the vehicles. An interruption is decided from the difference of the adjacent distance data. Only the distance data after the interruption is used and averaged thereby to calculate the distance between the two vehicles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-vehicle distance detecting device, and more particularly to an improvement in inter-vehicle distance detection when a rapid inter-vehicle distance change such as interruption occurs.

[0002]

2. Description of the Related Art Conventionally, for the purpose of reducing driver's driving operation and improving safety in driving on a highway or the like, a vehicle distance to a vehicle ahead is detected by using a laser beam, a millimeter wave, an ultrasonic wave or the like. A travel control system for controlling travel of the vehicle has been proposed.

In such a control system, needless to say, how to accurately measure the inter-vehicle distance to the vehicle ahead is the most important issue, and various attempts have been made to improve the accuracy and responsiveness of the inter-vehicle distance detecting device. ..

For example, in Japanese Patent Application No. 3-61691 previously proposed by the applicant of the present application, an average process is performed when an average value of distance data from a radar device is calculated to detect a vehicle-to-vehicle distance. A configuration is shown in which the calculation time is changed according to the speed, acceleration, relative speed, etc. of the vehicle. If the calculation time of the averaging process is lengthened, more distance data will be processed, and a more accurate inter-vehicle distance can be calculated, and if the calculation time is shortened, the number of distance data will be small, but in a short time. The inter-vehicle distance can be calculated with. Therefore, it is possible to calculate the inter-vehicle distance with necessary accuracy or time by appropriately increasing or decreasing the calculation time according to the traveling state of the preceding vehicle and the own vehicle, and use it as the control parameter such as the traveling control of the own vehicle. is there.

[0005]

However, when the state of the front vehicle changes suddenly, for example, when the third vehicle cuts in between the front vehicle and the own vehicle, the inter-vehicle distance detecting device quickly detects the inter-vehicle distance. It is necessary to detect the change in distance, but if the averaging process of the distance data was performed each time when detecting the inter-vehicle distance, it is possible to quickly obtain a new inter-vehicle distance (inter-vehicle distance to the interrupting vehicle). There was a problem I couldn't do.

For example, when the inter-vehicle distance is calculated by averaging five time-series distance data, the distance data processing is required five times to detect the actual inter-vehicle distance with the interrupting vehicle. The distance change during that time is 1 / of the total change
Only 5 (5 times data collection is required before all the time-series distance data becomes distance data with the interrupting vehicle). Therefore, even if the vehicle is interrupted, accurate inter-vehicle distance detection is delayed, and the inter-vehicle distance is displayed far even if there is an interrupting vehicle immediately before the own vehicle, or the inter-vehicle warning is delayed. The problem of will occur. Further, the relative speed with respect to the vehicle in front is often calculated from the change in the inter-vehicle distance over time, but the delay in detecting the inter-vehicle distance also causes the delay in detecting the relative speed, which causes a problem that the traveling control cannot be smoothly performed. Will end up.

The present invention has been made in view of the above problems of the prior art, and its object is to quickly respond to a sudden change in the inter-vehicle distance such as an interruption and to calculate an accurate inter-vehicle distance instantaneously. An object is to provide an inter-vehicle distance detecting device.

[0008]

In order to achieve the above object, an inter-vehicle distance detecting apparatus according to claim 1 calculates an inter-vehicle distance to a vehicle in front using distance data detected by a radar apparatus. In the distance detection device, for a predetermined number of distance data detected in time series by the radar device,
And a calculation means for calculating an inter-vehicle distance by calculating a weighted average using weights that increase in time series.

In order to achieve the above object, the inter-vehicle distance detecting apparatus according to the second aspect is an inter-vehicle distance detecting apparatus for calculating an inter-vehicle distance to a vehicle in front using distance data detected by a radar device. Comparing means for comparing the latest distance data Rt with the immediately preceding distance data Rt-1 among the distance data detected by the radar device in time series, and this comparing means with the latest distance data Rt and immediately before it. If the difference from the distance data Rt-1 is greater than or equal to a predetermined value and the difference between the next latest distance data Rt + 1 and the immediately preceding distance data Rt is less than or equal to the predetermined value, the latest distance data is detected. R
It is characterized in that it has a calculation means for calculating the inter-vehicle distance by calculating the average of t + 1 and the distance data Rt immediately before it.

[0010]

As described above, in the inter-vehicle distance detecting apparatus according to the first aspect of the present invention, the weight of the latest distance data indicating a sudden change such as an interruption is increased and the averaging process is performed, so that a value close to the actual inter-vehicle distance is returned. Calculate accurately.

Further, in the inter-vehicle distance detecting apparatus according to the second aspect, the presence or absence of an interruption or the like is determined from the difference in the adjacent distance data, and in the case of an interruption or the like, the averaging process is performed using only the adjacent distance data after the interruption. By doing so, the inter-vehicle distance is calculated with good responsiveness and accuracy.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of an inter-vehicle distance detecting apparatus according to the present invention will be described below with reference to the drawings.

First Embodiment FIG. 1 is a block diagram showing the configuration of a traveling control system using the inter-vehicle distance detecting device of this embodiment. A scanning laser radar device 10 is installed at the front part of the vehicle. As is well known, the scanning laser radar device scans a narrowed laser beam at a constant angle in a horizontal plane, and the distance from the time when the laser beam is transmitted to when it is reflected back to the object to the object. Is a device that measures the distance, and the distance to the object is calculated for each scan angle. The distance data and the angle data from the scan type laser radar device 10 are the control computer E
It is input to the CU 12.

On the other hand, a vehicle speed sensor 1 for detecting the vehicle speed of the vehicle.
4. A steering sensor 16 for detecting the steering angle of the own vehicle and a system operation switch 18 for turning on and off the operation of this device are provided at predetermined positions of the vehicle,
The detection signal is supplied to the ECU 12. The ECU 12 has an input port 12 to which a detection signal from each sensor is input.
a, a vehicle obstacle recognizing unit 12b that extracts an obstacle existing in front of the vehicle from the input detection signal, an arithmetic unit 12d that calculates an inter-vehicle distance and a relative speed to the extracted front vehicle, and outputs a processing signal to the outside The output port 12e is configured to include a memory 12f for storing data, and a control signal is output from the output port 12e according to a vehicle-to-vehicle distance and a relative speed with respect to a vehicle ahead to operate the throttle actuator 20 and the brake actuator 22. This is a configuration for controlling the traveling of the vehicle.

The characteristic feature of this embodiment is that the calculation unit 12d calculates a weighted average of the time-series distance data obtained by the scanning laser radar device 10 to calculate the inter-vehicle distance. It is in.

The EC will be described below with reference to the flowchart of FIG.
The operation of U12 will be described. When the system operation switch 18 is turned on (S101), initial setting and abnormality detection of the system are performed (S102). Then, the laser radar device 10 is operated to emit laser light (S10).
3). When the reflected light from the object is received, the measurement ends (S104), and the distance rt is calculated (S10).
5). This distance calculation is performed by measuring the time from laser light emission to reception. Even when the reflected light cannot be received, the measurement is terminated after a predetermined time has elapsed, and it is determined that there is no vehicle ahead.

After the distance rt is calculated, this distance rt is corrected (S106). This distance correction is an offset amount of the laser radar device 10, and the reception intensity C1 is set in advance.
And the circuit constant C2 are obtained, and the correction is performed by adding these constants to the distance rt. That is, the distance R
t = rt + C1 + C2. The sequentially calculated distance data Rt are sequentially stored in the memory 12f (S107).

The computing unit 12d averages a predetermined number (five in this embodiment) of time series distance data Rt stored in the memory 12f to calculate the inter-vehicle distance to the preceding vehicle. 12d does not calculate a simple average value of these time series distance data Rt, but calculates a weighted average with a weight that increases in time series to calculate the inter-vehicle distance (S108). For example, the five distance data obtained by going back to the past from the latest distance data are represented by Rt and R.
The weighted averages are calculated by assigning weights of 10, 5, 3, 2, 1 to these distance data as t-1, Rt-2, Rt-3, and Rt-4, respectively. That is, the inter-vehicle distance R
Rt is RRt = (10.Rt + 5.Rt-1 + 3.Rt-2 + 2.
Rt-3 + 1.Rt-4) / 21.

As described above, by increasing the weight of the latest distance data, even if the third vehicle is interrupted, the value of the actual distance data Rt after the interruption has a large weight and is averaged. It is possible to take a value close to this actual inter-vehicle distance.

In this embodiment, the above-mentioned weights are assigned to the five time-series distance data, and the inter-vehicle distance is detected with excellent responsiveness to changes while maintaining a certain degree of accuracy. It is needless to say that the distribution of the weighting and the weighting distribution can be appropriately set according to the nature of the system in which the inter-vehicle distance detecting apparatus of the present embodiment is used, for example, accuracy is required or response speed is required. Yes.

Second Embodiment In the above-described first embodiment, the number of data is fixed to 5 and the averaging process is performed, but in the second embodiment, the interrupt occurrence is automatically determined from the sudden change of the distance data. In this case, a case is shown in which the averaging process is performed provisionally using two pieces of distance data.

The basic structure is the same as that of the first embodiment described above, and the distance data obtained by the scan type laser radar device 10 is input to the ECU 12 and further corrected and then stored in the memory 12f. Then, after the arithmetic unit 12d performs the averaging process to calculate the inter-vehicle distance, the output port 12
The throttle actuator 20 and the brake actuator 22 are controlled via e.

FIG. 3 shows the ECU 12 in the second embodiment.
The operation flowchart of is shown. S201 to S2
07 is a step similar to S101 to S107 described above, and after the distance data obtained by the laser radar device 10 is corrected, it is sequentially stored in the memory 12f.

Next, the arithmetic unit 12d calculates the absolute value of the difference between the latest distance data Rt and the distance data Rt-1 immediately before it among the stored time series distance data, and calculates the absolute value of the difference. The predetermined value A is compared (S208). When the third vehicle interrupts, the latest distance data Rt shows the value after interruption, but the distance data Rt-1 immediately before that shows the value before interruption, so the absolute value of the difference is Becomes larger than the predetermined value A. Further, when some noise is mixed in the latest distance data Rt-1, it is considered that the value becomes the predetermined value A or more. Therefore, when the absolute value of the difference becomes equal to or larger than the predetermined value A, the inter-vehicle distance RRt-1 calculated last time is adopted as the inter-vehicle distance Rt this time (S209), and the latest distance data Rt + 1 is again obtained. Rt
And stores it in the memory 12f and shifts to the comparison step of S208.

When there is an interrupt, the latest distance data Rt at the above-mentioned time t indicates the distance after this interrupt, and the latest distance data R at the next processing time t + 1.
t (In this case, the latest distance data at time t is Rt-
(1) also indicates the distance after the interruption, so there is no big difference between the two data, so NO in S208.
Is determined. On the other hand, if noise is mixed in the latest distance data Rt-1 of the last time, it is determined to be YES this time,
Subsequently, the previous inter-vehicle distance RRt-1 is adopted as the inter-vehicle distance. Then, if NO is determined, it is determined whether or not YES is determined in the step S208 in the previous process, that is, | Rt-1 −Rt-2 |> A is satisfied (S210). ..

In the case of an interrupt, as described above, | Rt-
Since the condition of 1-Rt-2 |> A is satisfied, YES is determined, and in this case, the latest distance data Rt of this time (the latest data at time t + 1) and the distance data R immediately before that.
Using only t-1 (latest distance data at time t),
The inter-vehicle distance RRt is calculated by RRt = (RRt + RRt-1) / 2 (S211).

On the other hand, both last time and this time, | Rt-1 −Rt-2 |>
If the condition A is not satisfied, it is determined that there is no sudden change such as interruption or the mixing of noise, and the inter-vehicle distance is calculated by calculating a simple average of the five distance data (S21).
2).

As described above, in the second embodiment, it is determined from the sudden change in the distance data that an interruption has occurred, and the inter-vehicle distance is calculated using only the distance data after the interruption. It becomes possible to calculate the inter-vehicle distance with good responsiveness.

Although the inter-vehicle distance is calculated by the simple average in S212 of this embodiment, the inter-vehicle distance may be calculated by calculating the weighted average as in the first embodiment.

Further, although the laser radar device is used in the first and second embodiments, it goes without saying that an ultrasonic wave or millimeter wave radar device may be used.

[0031]

As described above, according to the inter-vehicle distance detecting apparatus of the present invention, it is possible to detect a sudden change in the inter-vehicle distance such as an interruption with high responsiveness and accuracy, and it has been incorporated into a traveling control system. In such cases, the reliability of the system can be significantly improved.

[Brief description of drawings]

FIG. 1 is a configuration block diagram of an embodiment of the present invention.

FIG. 2 is an operation flowchart diagram of the embodiment.

FIG. 3 is an operation flowchart of another embodiment.

[Explanation of symbols]

 10 Laser Radar Device 12 ECU 20 Throttle Actuator 22 Brake Actuator

Claims (2)

[Claims] 1. An inter-vehicle distance detecting device for calculating an inter-vehicle distance to a vehicle in front using distance data detected by a radar device, wherein a predetermined number of distance data detected in time series by the radar device An inter-vehicle distance detecting device, comprising: an arithmetic unit that calculates an inter-vehicle distance by calculating a weighted average using weights that increase in time series. 2. An inter-vehicle distance detecting device for calculating an inter-vehicle distance to a vehicle in front using distance data detected by the radar device, wherein the latest distance among the distance data detected in time series by the radar device. Data Rt and distance data Rt-1 immediately before it
And the difference between the latest distance data Rt and the distance data Rt-1 immediately before that is greater than or equal to a predetermined value by this comparing means, and the next latest distance data Rt + 1 and the distance data immediately before that. When it is detected that the difference from Rt is less than or equal to a predetermined value, an arithmetic means for calculating the inter-vehicle distance by calculating the average of the latest distance data Rt + 1 and the distance data Rt immediately before it is provided. Characteristic vehicle distance detection means.