JPH0620200A - Trigonometrical survey type range finder and inter-vehicle distance control device - Google Patents

Abstract

PURPOSE:To improve resolution at a long distance so as to obtain a stable measured value with small fluctuation by changing a filter constant in accordance with the measured value of the measured distance. CONSTITUTION:A trigonometrical survey type measuring instrument is used as a distance sensor 30, and a control device 31 executes the filtering processing of the measured value of inter-vehicle distance by changing the filter constant in accordance with the measured value measured by this trigonometrical survey type measuring instrument. That is, at the time of calculating the distance in the control device 31, a result is obtained by putting a filter in the way of software. This secures the high resolution and the stability of the measured value extending over a range from a short distance to a long distance by enlarging the number of the samples of moving average, that is, to enlarge the filter constant as the distance becomes longer by executing the moving average at the time of aruthmetic operation. Thus, a problem that the speed of a vehicle fluctuates always and the vehicle is made unconfortable to ride or the problem that safe travel is endangered because a measure to cope with the vehicle breaking into a queue, etc., is delayed when the speed of the vehicle is controlled by lowering the control gain of the control device can be solved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a triangulation rangefinder that optically measures a distance by a triangulation method.

The present invention also relates to a vehicle travel control device, and more particularly to a device for controlling the vehicle distance by measuring the vehicle distance and controlling the vehicle speed.

[0003]

2. Description of the Related Art As a vehicle distance measuring means, there is a triangulation method. FIG. 6 is a configuration explanatory view showing a configuration of a conventional triangulation type distance measuring device disclosed in, for example, Japanese Patent Publication No. 63-46363. Also, for example, Japanese Patent Publication Sho 6
The configuration of the distance measuring device disclosed in JP-A-2-33522 is shown in FIG. 7, and the configuration of the distance measuring device disclosed in JP-B-63-44169 is shown in FIG.

The operating principle of the triangulation type rangefinder will be described with reference to FIG. The range finder has a base line length L and a pair of optical systems 2 and 12 and image sensors 3 and 13,
It is composed of analog / digital converters (hereinafter referred to as A / D converters) 4 and 14, memories 5 and 15, an image processing device 20, and a computer 21 (hereinafter referred to as CPU).

Next, the operation will be described. The image of the object 1 is projected onto the respective image sensors 3 and 13 through the pair of optical systems 2 and 12. The image signals converted into electric signals by the image sensors 3 and 13 are converted into digital signals by the A / D converters 4 and 14, and are stored in the memories 5 and 15, respectively.

The above image signals are sequentially read by a command from the CPU 21 and sent to the image processing circuit 20.
The image processing circuit 20 calculates the correlation between both image signals. That is, in order to measure the distance to the object 1, the correlation calculation is performed while the image signal of the other image sensor is shifted pixel by pixel with respect to the signal of the object 1 on one image sensor.

As a result of performing the correlation calculation as described above, the pixel shift amount (a + b) when the correlation is best obtained for the object in the pair of images, the pixel and the pitch P are also obtained.
And the distance R from the base line length L and the focal length f of the lens to the object are calculated by the following equation (1). R = f · L / {(a + b) · P} (1)

In the case of the device shown in FIG. 7, the CPU 21
The driver 16 drives the light emitting element 11 according to the command of 1. and the emitted light irradiates the object 1, and the optical system 2 forms an image of the spot light on the image sensor 3. The image signal at that time is sent to the signal processing device 20A, and the shift amount a of the pixel from the reference position is detected.

As a result, the pixel pitch P and the base line length L
And the focal length f of the lens, as in the case of FIG.
The distance R to the object 1 is calculated by the following equation (2). R = f · L / (a · P) (2)

In FIG. 8, the image sensor 3 in FIG. 7 is replaced with an analog position sensor 3A. Assuming that the amount of deviation of the imaging position from the reference position at this time detected by the signal processing device 20B based on the output signal of the position sensor 3A is d, the distance R to the object 1 is calculated by the following equation (3). Is required. R = f · L / d (3)

In the above-mentioned conventional example, the case where the distance measuring device is applied to the inter-vehicle distance control device has been described, but the distance measuring device can be used alone for distance measurement.

On the other hand, as a method for controlling the inter-vehicle distance by a measuring method other than triangulation, for example, Japanese Patent Laid-Open No. 48-54631.
As disclosed in Japanese Patent Publication No. 62-38760 and Japanese Patent Publication No. 62-38760, a means for measuring an inter-vehicle distance between a host vehicle and a preceding vehicle, a means for generating a safe inter-vehicle distance, and a vehicle speed for ensuring a safe inter-vehicle distance. And means for controlling the.

Further, these publications disclose a radar device as an inter-vehicle distance measuring means. The radar device as described above uses a method of emitting radio waves or light, receiving radio waves or light reflected by a preceding vehicle, and obtaining the inter-vehicle distance from the round trip time of the transmission and reception. Fluctuations in the measured values by this radar device are determined by fluctuations in time measurement. The magnitude of the fluctuation hardly depends on the distance to be measured as long as the emitted radio wave or light catches the target preceding vehicle.

[0014]

Since the conventional triangulation type distance measuring device is constructed as described above, since the distance is inversely proportional to the deviation amount in the calculation of the distance, the resolution becomes worse as the distance increases. However, there was a problem that the fluctuation became large.

On the other hand, in the radar device in the conventional inter-vehicle distance control device, the beam of radio waves or light emitted from the radar device mounted on the vehicle while the vehicle is traveling is shaken by the vehicle body depending on the road surface condition, so that the beam moves up, down, left and right. Wobble. For this reason, the radio waves and light sometimes come off from the preceding vehicle, are reflected from the road surface, are reflected by roadside structures, or are reflected by other vehicles running in parallel and then return. In a radar device, when radio waves or light that is reflected by a vehicle other than the preceding vehicle as well as reflected by other vehicles than the preceding vehicle is received, the measured values often fluctuate. Will be a big one. In particular, when the inter-vehicle distance is longer than the short distance, even if the pointing direction of the radio wave or light beam is deviated by a shallow angle, the deviation from the preceding vehicle is likely to occur, and the above problem occurs.

If vehicle speed control is performed so as to maintain the inter-vehicle distance at a predetermined value based on the measurement value of the distance sensor with fluctuations as described above, the vehicle speed always fluctuates and the riding comfort of the vehicle becomes extremely poor. There was a problem. However, if the vehicle speed is controlled by lowering the control gain of the inter-vehicle distance control device in order to improve the riding comfort, there is a problem in that the handling of an interrupting vehicle or the like is delayed and the vehicle runs into danger.

The present invention has been made in order to solve the above problems, and provides a triangulation rangefinder capable of improving resolution at a long distance, absorbing fluctuations, and obtaining stable measurement values. To obtain good and comfortable ride of the car,
Another object of the present invention is to provide a vehicle-interval distance control device that is safe for traveling and can respond quickly to coping with an interrupting vehicle.

[0018]

A triangulation rangefinder according to the invention described in claim 1 obtains a measurement result by changing a filter constant according to a measured value of a distance measured by a triangulation type distance measuring device. It is provided with a filter.

A triangulation type rangefinder according to a second aspect of the present invention is the triangulation type rangefinder according to the first aspect, wherein the filter constant is increased as the distance increases.

According to a third aspect of the present invention, there is provided an inter-vehicle distance control device, which comprises, as an inter-vehicle distance measuring means, a sensor for detecting a vehicle through an optical system and a deviation amount of a signal detected by the sensor. And a calculation means for calculating the distance to the object to be measured, wherein the calculation means has a filtering function, and the filter constant in this filtering function uses a triangulation rangefinder having a value corresponding to the measured distance. is there.

An inter-vehicle distance control device according to a fourth aspect of the present invention is an inter-vehicle distance control device having an inter-vehicle distance measuring means and a control means for controlling a vehicle speed based on the output of the inter-vehicle distance measuring means. The control gain is changed according to the measured value.

According to a fifth aspect of the present invention, there is provided an inter-vehicle distance control device having a target inter-vehicle distance setting means, an inter-vehicle distance measuring means, and a means for detecting a deviation between the inter-vehicle distance and the target inter-vehicle distance. The gain is multiplied and the target vehicle speed is set based on the multiplied deviation value.

In the inter-vehicle distance control device according to the invention of claim 6, in claim 5, the value of the multiplied deviation is
It is a value obtained by multiplying the deviation before multiplication by each of a predetermined proportional gain, integral gain, and differential gain, and summing these gains.

According to a seventh aspect of the present invention, there is provided an inter-vehicle distance control device in which the inter-vehicle distance is a long distance.
The proportional gain and / or the differential gain are reduced, and are increased when the distance is short.

In the inter-vehicle distance control device according to an eighth aspect of the present invention, in the sixth aspect, the temporal change rate of the value measured by the inter-vehicle distance measuring means is used as the term of the value obtained by integrating the differential gain with the deviation. The value obtained by filtering is used.

According to a ninth aspect of the present invention, there is provided an inter-vehicle distance control device in which the control means includes a filter having a temporal change rate of the measured value of the inter-vehicle distance, the filter constant of which changes according to the measured value. The value obtained by the filtering process is used.

According to a tenth aspect of the invention, there is provided an inter-vehicle distance control device according to the eighth or ninth aspect, in which the filter constant is increased as the distance increases.

According to an eleventh aspect of the present invention, in the inter-vehicle distance control device, in the device, the control means has a filter having a filter constant having a rate of temporal change of the measured value of the inter-vehicle distance of 4 times or more of the sampling period. The value obtained by the filtering process is used.

According to a twelfth aspect of the present invention, in the inter-vehicle distance control device, when the temporal change rate of the inter-vehicle distance measured value exceeds a predetermined value, the inter-vehicle distance value measured immediately before is measured. The corresponding control gain is used.

[0030]

In the triangulation rangefinder according to the first aspect of the present invention, the distance is calculated by changing the filter constant in the filtering function of the calculation means according to the measurement distance. Ensure high resolution and stability of measured values from to long distance.

In the triangulation rangefinder according to the second aspect of the present invention, since the fluctuation becomes greater as the distance increases, the filter constant becomes larger as the distance increases to eliminate the influence.

An inter-vehicle distance control device according to a third aspect of the present invention uses the triangulation rangefinder according to the first aspect to obtain a stable inter-vehicle distance measurement value and controls the vehicle speed based on the obtained value. Therefore, it is possible to improve the riding comfort of the automobile and the response of the vehicle speed control.

According to the inter-vehicle distance control device of the present invention, the control gain is changed in accordance with the measured value of the inter-vehicle distance to control the vehicle speed, thereby the responsiveness of the vehicle speed control at a short distance and the riding distance at a long distance. You can improve your comfort.

In the inter-vehicle distance control apparatus according to the present invention, the deviation between the measured inter-vehicle distance and the target inter-vehicle distance is multiplied by a predetermined gain, and the target vehicle speed is set based on the value of the multiplied deviation. Improving the ride quality of the car with fast response vehicle speed control.

In the inter-vehicle distance control system according to the sixth aspect of the present invention, the feedback system in the action of the fifth aspect acts as proportional, integral and differential control.

In the inter-vehicle distance control device according to the seventh aspect of the present invention, in the action of the sixth aspect, the proportional gain and / or the differential gain are reduced when the inter-vehicle distance is a long distance and large when the inter-vehicle distance is a short distance. For long distances with large fluctuations in measured values, the vehicle speed control with slow response improves the riding comfort, and for short distances with small fluctuations in measured values, quick response vehicle speed control is performed to prevent the risk of collision. .

In the inter-vehicle distance control apparatus according to the present invention as defined in claim 8, in the operation of claim 6, the variation rate of the measured inter-vehicle distance measured over time is filtered as the term of the value obtained by integrating the differential gain with the deviation. By using the value obtained in this way, the riding comfort of the vehicle is improved better.

According to the inter-vehicle distance control apparatus of the present invention, the measured value of the inter-vehicle distance is measured against the pulse-like disturbance of the measured value of the inter-vehicle distance by filtering the temporal change rate of the inter-vehicle distance. A smooth vehicle speed control can be realized by smoothing the temporal change rate of, and using this value as a differential term, thereby improving the riding comfort of the vehicle.

In the inter-vehicle distance control apparatus according to the twelfth aspect of the present invention, when the temporal change rate of the measured value of the inter-vehicle distance exceeds a predetermined value, the measured value of the inter-vehicle distance is an abrupt change and the measured value is abnormal. By using the control gain corresponding to the measured value immediately before, it is possible to eliminate the influence on the vehicle speed control due to the abnormal measured value due to the disturbance due to noise or the disturbance due to the vehicle bouncing.

[0040]

EXAMPLES Example 1. Hereinafter, embodiments of the triangulation type distance meter of the present invention will be described with reference to the drawings. The triangulation type distance measuring device applied to the present invention is applicable to any of the conventional triangulation type distance measuring devices shown in FIGS. 6 to 8 and is measured by such a distance measuring device. The filter constant is changed according to the measured value of the distance. The configuration of the distance measuring device based on the triangulation method applied to the present invention is as described with reference to FIGS. 6 to 8, and redundant description will be omitted here.

Next, the operation of the present invention will be described.
FIG. 1 shows an example of a flow chart for determining the filter constant in the present invention, which will be described with reference to this figure. The filter in the present invention calculates the distance in the CPU 21 shown in FIGS. Sometimes, software is used to filter and obtain the measurement result, and the moving average is calculated when calculating this distance. The longer the distance, the larger the number of samples of the moving average, that is, the filter. By increasing the constant,
High resolution and stability of measured values can be secured from short range to long range.

First, in step S1, a value R _n measured this time is obtained from the deviation amount obtained by the correlation calculation of a pair of image signals by the distance measuring device by the triangulation method, by the equation (1). The conventional distance measuring device outputs the R _n thus obtained as a result. For example, an image signal is input and calculated every 60 milliseconds, and the result is output moment by moment.

However, in this embodiment, the measured value of this time is not used as a result as it is, but the measured value of several times before is incorporated, such as the last time, the time before the last time, the time before the time, and so on. It is designed to produce the results of. The value R ₀ of the previous filtering is a value obtained by incorporating the values up to several times before.

In the next step S2, the constant K for determining the weaving method is obtained from the table. This table is as shown in Table 1 below and defines a constant K for the result R ₀ after the previous filtering. For example, when R ₀ = 45 m, K = 4.

[0045]

[Table 1]

In the next step S3, the result after filtering by the following equation (4) is obtained using this constant K. R = (R _n / K) + {((K-1) · R ₀ ) / K} (4) This expression (4) strongly reflects the current value when K is small, and increases as K increases. , Greatly reflects past values. That is, K corresponds to the time constant of the filter.

The value R thus obtained is used as R _{0 in the} next measurement, a new K _{0 is} also obtained, and the value at the next timing is calculated. This is continued one after another, and the value of the distance is output every 60 milliseconds.

FIG. 3 is a diagram showing the structure of an inter-vehicle distance control apparatus according to an embodiment of the present invention. Reference numeral 30 is a distance sensor as an example of an inter-vehicle distance measuring means for measuring the inter-vehicle distance from the own vehicle to the preceding vehicle, and the above-mentioned triangulation type distance sensor or radar device can be used. Reference numeral 31 is a control device, which includes a microcomputer and an input / output circuit. A throttle actuator 32 drives a throttle valve that adjusts the opening of an intake pipe of the engine, and controls the output of the engine. Reference numeral 33 is a brake actuator for operating the brake, which is for reducing the vehicle speed.

The control unit 31 has an input unit connected to the distance sensor 30, a vehicle speed sensor 34 for detecting the vehicle speed, and a throttle opening sensor 35 for detecting the opening of the throttle valve, and an output unit for the throttle actuator 32, Brake actuators 33 are respectively connected to the actuators 32, 3 based on their input signals.
The vehicle speed is controlled by controlling 3.

FIG. 4 shows a PID control (proportional,
FIG. 3 is a block diagram of a control system for control by integration and differentiation).
First, the vehicle speed at this point is detected, and a target inter-vehicle distance value R _s representing a target inter-vehicle distance is calculated from this vehicle speed signal. The distance deviation ΔR between the target inter-vehicle distance value R _s and the measured value R of the inter-vehicle distance at this point is taken. The distance deviation ΔR is multiplied by a proportional gain, an integral gain, and the like, and the temporal change rate of the distance deviation ΔR is obtained, and this is multiplied by a derivative gain, and the proportional amount, integral amount, and derivative amount of the distance deviation are obtained. The target vehicle speed value v _s representing the target vehicle speed is calculated by taking the sum. Next, the vehicle speed deviation Δv between the target vehicle speed value v _s and the actual vehicle speed value v _a representing the current vehicle speed is calculated. Based on this vehicle speed deviation Δv, control gains such as proportional, integral, and derivative are multiplied in the same manner as above to calculate the actuator drive control amount, which is output to the throttle actuator and the brake actuator to control the vehicle speed. To do.

FIG. 2 is a flow chart showing the operation procedure of the control device 31 shown in FIG. 3. The operation of the embodiment will be described mainly with reference to FIGS. 2 and 3.

The distance sensor 30 measures the inter-vehicle distance and outputs the measured value of the inter-vehicle distance. In addition, the vehicle speed sensor 34
Detects the vehicle speed and outputs a vehicle speed signal representing this vehicle speed. Further, the throttle opening sensor 35 detects the opening of the throttle valve and outputs a throttle opening signal representing this throttle opening. First, in step S11, the distance sensor 30, the vehicle speed sensor 34, the throttle opening sensor 3
Signals from each sensor such as 5 are data values (inter-vehicle distance value,
Read with vehicle speed value and throttle opening value).

In step S12, the measured vehicle speed value v _a
A target inter-vehicle distance value R _s representing the target inter-vehicle distance according to is calculated. The method of obtaining the target inter-vehicle distance value R _s is generally as follows.
It may be obtained by the following equation (5) as being proportional to the square of the measured vehicle speed value v _a , or may be obtained from this table by setting a target inter-vehicle distance value for the vehicle speed value in a data table. _{R s = C o · v a} 2 ... (5) where, R _s is a target inter-vehicle distance value, C _o is a constant, v _a is the vehicle speed value. It should be noted that C _o can be changed depending on the road and weather conditions.

In step S13, the target inter-vehicle distance value R _s
Then, a distance deviation ΔR = R−R _s between the measured value R and the inter-vehicle distance is obtained, and this is multiplied by a proportional gain G _P to obtain a value G _P · ΔR. Incidentally, the proportional gain is a gain to be multiplied by ΔR, and if the deviation becomes large, it becomes a large value in proportion to it. Also, a value G _I · ΔR multiplied by the integral gain G _I which is a small value
Is added to the value at the previous timing to obtain the value at this timing. When multiplied by G _I , ΔR changes gradually.
Next, a value G _D · dΔR / dt obtained by multiplying the time change rate dΔR / dt of the distance deviation ΔR from the previous time to the present time by a large differential gain G _D , and adding the above three values to a value G _P・ ΔR + (Integrated value of G _I・ ΔR) + (G _D・ dΔR
/ Dt) is calculated. At this time, as the control gains, the proportional gain G _P , the integral gain G _I , and the differential gain G _D are values corresponding to the inter-vehicle distance value in a data table, and the inter-vehicle distance measured by the distance sensor 30, that is, the inter-vehicle distance is measured. It is obtained from the value R by table lookup.

Since the measured value R of the inter-vehicle distance has a large fluctuation as the distance increases, in the case of a long distance, the proportional gain G _P and the differential gain G _D are made extremely small, and the vehicle speed control mainly including the integral gain G _I is performed. Good to do. In this case, even if there is a slight response delay in the vehicle speed control for setting the inter-vehicle distance to the target inter-vehicle distance, the risk of collision between vehicles is small. Therefore, it is better to give priority to the relaxed riding comfort by slowly changing the vehicle speed rather than changing frequently, rather than the vehicle speed changing frequently and making the riding comfort of the vehicle worse.

When the measured value R of the inter-vehicle distance is a short distance,
The fluctuation is small. In this case, if the rate of temporal change in the inter-vehicle distance is large, the risk of collision increases, so the value dΔR
When / dt is negative, that is, when the inter-vehicle distance is about to become short, it is preferable from a safety point of view to increase the differential gain G _D or the proportional gain G _P to increase the responsiveness of the vehicle speed control. The above data table, the proportional gain G _P depending on the perspective of the inter-vehicle distance as described above, the integral gain G _I, the differential gain G _D are stored settings.

In step S14, the target vehicle speed value v _s representing the target vehicle speed is calculated using the value obtained in step S13. This v _S is calculated by, for example, the vehicle speed and the inter-vehicle distance as a function of a value obtained by multiplying ΔR by a gain. Further, the calculated value may be called from the set table.

[0058] In step S15, obtains a speed deviation Delta] v = v _a -v _s and obtained by actually measuring the vehicle speed value v _a and the target vehicle speed value v _s, similar to that performed in step S13 based on the speed deviation Delta] v By various calculation methods, the respective gains of proportional, integral, and derivative are obtained from a predetermined data table for the inter-vehicle distance value or the vehicle speed value, and a predetermined calculation is performed to obtain the control amount.

In step S16, it is determined whether to accelerate or decelerate based on the control amount obtained in step S15.

If it is determined to be acceleration, the process proceeds to step S17,
Based on the control amount and the throttle opening value, the angle for opening the throttle valve with respect to the current throttle opening is calculated, that is, the actuator control amount corresponding to the target throttle opening is calculated and output to the throttle actuator 32.

If it is determined in step S16 that the vehicle is decelerating, the process proceeds to step S18, in which the angle for closing the throttle valve with respect to the current throttle opening is calculated based on the control amount and the throttle opening value obtained in step S15. That is, the actuator control amount corresponding to the target throttle opening is calculated and output to the throttle actuator 32.

In the next step S19, step S18
From the calculation result of, it is judged whether the control amount is insufficient by simply closing the throttle valve, that is, whether the brake control is necessary,
If it is determined that it is necessary, the process proceeds to step S20 to calculate the control amount for braking and output it to the brake actuator 33. The inter-vehicle distance control is performed by repeating the above steps.

Example 2. The different point from the first embodiment is that the triangulation distance meter described in the first embodiment is used as the inter-vehicle distance measuring means for measuring the inter-vehicle distance. A triangulation measurement device is used as the distance sensor 30 shown in FIG. 3, and the control device 31 filters the inter-vehicle distance measurement value by changing the filter constant according to the measurement value measured by the triangulation measurement device. It has a filter function. In this embodiment, as in the first embodiment, the gain may be changed according to the measured value of the inter-vehicle distance or the vehicle speed value,
Alternatively, it may be fixed. In particular, even in the short distance, even if the filter constant is made small, the resolution is high and the response is fast, and it is effective for warning and control of the inter-vehicle distance. At a long distance, the response is slightly delayed by increasing the filter constant, but the resolution is high, the inter-vehicle distance can be stably measured, and the driving feeling is improved.

Example 3. The distance sensor 30 shown in FIG.
Whether it is a radar device or a triangulation method, measurement values can be obtained at a certain sampling period Δt. Therefore, when the fluctuation of the measured value of the inter-vehicle distance is large, dΔ
R / dt goes back and forth between positive and negative, or suddenly becomes a large value. In order to improve the riding comfort of the vehicle in such a case, a point different from the first embodiment is that dΔR / dt is filtered to mitigate a sudden change. FIG. 5 is a diagram showing a flow of operations of the filtering process. still,
Although the value of dΔR / dt is set to a small value at a long distance, since the change in the differential term still affects the riding comfort, the filtering process is performed on this.

In FIG. 5, in step S21, a distance deviation ΔR _n = R _n -R _n-1 is calculated from the previously measured inter-vehicle distance measurement value R _n-1 and the presently-measured inter-vehicle distance measurement value R _n. To do.

In step S22, from the distance deviation ΔR _n and the sampling (measurement time) interval Δt, the temporal change rate of the distance deviation ΔR is calculated as the temporal change rate ΔV _n = ΔR _n / Δt. Calculated and used.

In step S23, the filter constant C for the measured value R _n of the inter-vehicle distance is read from a table in which the relationship between the inter-vehicle distance value and the filter constant is stored in advance as a data table.

In step S24, assuming that the previous result of the temporal change rate of the measured value of the inter-vehicle distance is ΔV ₀ ^n-1 , the present result ΔV ₀ ⁿ is obtained by using the following equation (6). ΔV ₀ ⁿ = (ΔV _n / C) + {(C-1) · ΔV ₀ ^n-1 / C} (6) By increasing the filter constant C, the influence of fluctuations in the measured value of the inter-vehicle distance is reduced. it can. This ΔV ₀ ⁿ may be used as dΔR / dt in step S13 shown in FIG. In this embodiment, the differential gain G _D may be the same as that in the first embodiment, or the value corresponding to the distance of the inter-vehicle distance may be closer or constant than that in the first embodiment.

Regarding the magnitude of the filter constant C, the filter constant C is set to be large for a long distance where the fluctuation of the inter-vehicle distance measured value is large, and the filter constant C is set for a short distance where the fluctuation of the inter-vehicle distance measured value is small. By reducing, the response can be slowed down at a long distance to improve the riding comfort, and the response can be speeded up at a short distance to avoid the risk of collision with the vehicle.

Example 4. The difference from the third embodiment is that the filter constant C is determined as follows. When an image processing type sensor is used as the distance sensor 30 shown in FIG. 3, it usually takes 0.03 seconds to sample one screen, and if the distance calculation time is added to this, it is 0.05 to 0.1.
It takes seconds. The measured value of the inter-vehicle distance can be obtained in the time of 0.05 to 0.1 seconds. Further, in consideration of a cycle such as bouncing or lateral shaking of an automobile, it is preferable to use a filter having a filter constant of about 0.2 seconds. That is, the filter constant C in the above equation (6) should be set to 4 times or more of the sampling period (0.05 to 0.1 seconds above) (the smaller one of 0.05 to 0.1 seconds above is set. As a standard, this resulted in a four-fold increase. The larger the filter constant C, the better the riding comfort of the automobile, but the response of the vehicle speed is deteriorated.

Example 5. The difference from the first embodiment is that in step S13 shown in FIG. 2, when the temporal change rate of the measured value of the inter-vehicle distance exceeds a predetermined value, the measured value of the inter-vehicle distance measured immediately before, that is, the previous time is measured. The point is to use the gain. As a result, the influence of the measurement error of the inter-vehicle distance due to the disturbance due to noise or the bouncing of the vehicle can be reduced.

In each of the above embodiments, the temporal change rate of the inter-vehicle distance measured value is the temporal change rate of the deviation between the current and previous inter-vehicle distance measured values and the temporal change rate of the distance deviation ΔR dΔ.
Since it can be used as R / dt (temporal change rate of the deviation between the inter-vehicle distance value measured this time and the target value), if one of them can be used in the above embodiment, the other can be applied instead. Needless to say, of course.
For example, in Example 1, instead of dΔR / dt, dΔR
_n / dt can be used. The same applies to the vehicle speed value as well as the inter-vehicle distance value.

[0073]

According to the invention described in claims 1 and 2, since the filter constant is changed according to the measured value of the distance by the triangulation type distance measuring device, a high resolution is obtained from a short distance to a long distance. It is possible to obtain stable measurement results with little fluctuation.

According to the third and fourth aspects of the invention, the distance is measured as in the first or second aspect to control the inter-vehicle distance, so that the influence of fluctuations on the inter-vehicle distance control can be almost eliminated. It is possible to control with good responsiveness at a short distance, and to improve riding comfort at a long distance.

According to the invention described in claims 5 to 7, the deviation between the inter-vehicle distance and the target inter-vehicle distance is multiplied by a predetermined gain, and the target vehicle speed is set based on the value of the multiplied deviation, or the gain thereof is set. Since proportional, integral, and differential gains are selectively used as, the response can be improved at a short distance and the riding comfort can be improved at a long distance.

According to the invention of claim 8, the value obtained by filtering the temporal change rate of the inter-vehicle distance value is used as the term of the value obtained by integrating the differential gain with the deviation in claim 6. Therefore, it is possible to alleviate a rapid change in vehicle speed and improve the riding comfort of the vehicle.

According to the ninth and tenth aspects of the present invention, since the filter constant for filtering the temporal change rate of the measured value of the inter-vehicle distance is used, a quick response is made to an interrupting vehicle or the like at a short distance. Since the danger of collision can be avoided, safety can be improved, and fluctuations can be mitigated at long distances to improve riding comfort.

According to the eleventh aspect of the present invention, since the filter constant is configured to be four times or more the sampling period, it is possible to eliminate the influence of fluctuation due to the bouncing of the vehicle and improve the riding comfort of the vehicle. it can.

According to the twelfth aspect of the invention, when the temporal change rate of the inter-vehicle distance value exceeds the predetermined value, the control gain corresponding to the inter-vehicle distance value measured immediately before is used. It is possible to reduce the influence of the measurement error of the inter-vehicle distance due to the disturbance due to noise or the bouncing of the vehicle, and the driving safety can be further improved.

[Brief description of drawings]

FIG. 1 is a flowchart for explaining how to determine a filter constant in a triangulation rangefinder according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation procedure of the control device of the inter-vehicle distance control device according to the embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of an apparatus according to the embodiment.

FIG. 4 is a block diagram of a control system according to the embodiment.

FIG. 5 is a flowchart showing a main part operation procedure of the control device of the inter-vehicle distance control device according to the embodiment of the present invention.

FIG. 6 is a configuration diagram of a conventional triangulation type distance measuring device.

FIG. 7 is a configuration diagram of a conventional triangulation type distance measuring device.

FIG. 8 is a configuration diagram of a conventional triangulation type distance measuring device.

[Explanation of symbols]

 1 Object 11 Light-Emitting Element 2, 12 Optical System 3, 13 Image Sensor 4, 14 A / D Converter 5, 15 Memory 16 Driver 20 Image Processing Circuit 20A, 20B Signal Processing Device 21 CPU 30 Distance Sensor 31 Control Device 32 Throttle Actuator 34 Vehicle speed sensor 35 Throttle opening sensor

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Claims (12)

[Claims] 1. A triangulation comprising a sensor for detecting an object to be measured via an optical system, and a calculation means for calculating a distance to the object to be measured from the amount of deviation of a signal detected by the sensor. The triangulation type range finder, wherein the calculating means has a filtering function, and the filter constant in the filtering function is a value corresponding to the measured distance. 2. The triangulation type rangefinder according to claim 1, wherein the filter constant is increased as the distance increases. 3. An inter-vehicle distance control device having an inter-vehicle distance measuring means for measuring an inter-vehicle distance and a control means for controlling a vehicle speed based on the inter-vehicle distance measuring means, wherein the inter-vehicle distance measuring means comprises an optical system of a vehicle. A sensor for detecting the distance and a calculating means for calculating the distance to the object to be measured from the deviation amount of the signal detected by the sensor,
The inter-vehicle distance control device is characterized in that the calculating means has a filtering function, and a triangulation type range finder in which the filter constant in the filtering function is a value according to the measured distance is used. 4. An inter-vehicle distance control device having an inter-vehicle distance measuring means for measuring an inter-vehicle distance and a control means for controlling a vehicle speed based on an output of the inter-vehicle distance measuring means, wherein the control means controls the vehicle speed. The inter-vehicle distance control device is characterized in that the control gain is changed according to the measurement value of the inter-vehicle distance measuring means. 5. A means for setting a target inter-vehicle distance, a means for measuring the inter-vehicle distance, a means for detecting a deviation between the inter-vehicle distance and the target inter-vehicle distance, and a means for setting a target vehicle speed according to the deviation. In the inter-vehicle distance control device having the above-mentioned, the inter-vehicle distance control device is characterized in that the deviation is multiplied by a predetermined gain and the target vehicle speed is set based on the value of the multiplied deviation. 6. The multiplied deviation value is obtained by multiplying the deviation before multiplication by each of a predetermined proportional gain, integral gain, and differential gain, and obtaining the sum of the values obtained by accumulating these gains. The inter-vehicle distance control device according to claim 5, wherein 7. If the measured inter-vehicle distance is a long distance,
The inter-vehicle distance control device according to claim 6, wherein the proportional gain and / or the differential gain are reduced, and the proportional gain and / or the differential gain are increased for a short distance. 8. The inter-vehicle distance according to claim 6, wherein a value obtained by filtering a temporal change rate of the value measured by the inter-vehicle distance measuring means is used as the term of the value obtained by integrating the differential gain with the deviation. Control device. 9. An inter-vehicle distance measuring means for measuring an inter-vehicle distance, and a vehicle speed PID based on an output of the inter-vehicle distance measuring means.
In an inter-vehicle distance control device having control means for controlling,
The control means is characterized by using a temporal change rate of the value measured by the inter-vehicle distance measuring means, a value obtained by filtering using a filter whose filter constant changes in accordance with the measured inter-vehicle distance value. Inter-vehicle distance control device. 10. The inter-vehicle distance control device according to claim 8 or 9, wherein the filter constant is increased as the distance increases. 11. An inter-vehicle distance measuring means for measuring an inter-vehicle distance, and a vehicle speed PID based on an output of the inter-vehicle distance measuring means.
In an inter-vehicle distance control device having control means for controlling,
The control means uses a value obtained by filtering the temporal change rate of the value measured by the inter-vehicle distance measuring means using a filter having a filter constant four times or more the sampling cycle of the inter-vehicle distance measuring means. An inter-vehicle distance control device characterized by: 12. An inter-vehicle distance control device having an inter-vehicle distance measuring means for measuring an inter-vehicle distance and a control means for controlling a vehicle speed based on an output of the inter-vehicle distance measuring means, wherein the control means controls the vehicle speed. The control gain for changing according to the measurement value of the inter-vehicle distance measuring means, and when the temporal change rate of the value measured by the inter-vehicle distance measuring means exceeds a predetermined value, was measured immediately before that. An inter-vehicle distance control device using a control gain corresponding to an inter-vehicle distance value.