JP2010176540A - Stop distance estimation system and method for calculating and estimating stop distance by use of stop distance estimation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stop distance estimation system and method, allowing calculation of a stop distance with high accuracy. <P>SOLUTION: In this stop distance estimation system, a control part 20 includes: an initial speed setting means 203 setting an initial speed; a correction means 204 correcting expression 1 of v=v<SB>0</SB>-μgt+μgτ(1-e<SP>-t/τ</SP>) based on an error between a deceleration measurement speed and a calculation speed; a determination means 205 determining a deceleration degree and a time constant based on a difference between a measurement acceleration and a calculation acceleration; a stop time calculation means 206 calculating a stop time by use of the corrected expression, the initial speed, the deceleration degree, and the time constant; and a stop distance calculation means 207 calculating the stop distance by expression 2 of d<SB>s</SB>=v<SB>0</SB>t<SB>s</SB>-μgt<SB>s</SB><SP>2</SP>/2+μgτät<SB>s</SB>-τ(1-e<SP>-ts/τ</SP>)}. In the expression 1, v is the calculation speed; v<SB>0</SB>is the initial speed; μg is the deceleration degree; t is a deceleration time that is a time lapsed with a deceleration start time as a reference; and τ is the time constant. In the expression 2, d<SB>s</SB>is the stop distance; and t<SB>s</SB>is the stop time. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a stop distance estimation system capable of calculating a stop distance of a measurement object such as a traveling vehicle and a method for calculating and estimating a stop distance using the stop distance estimation system.

Conventionally, as this kind of stop distance estimation system, in order to calculate a speed (threshold speed) at which a vehicle as a measurement object can stop safely up to a predetermined position such as an intersection, the stop distance of the vehicle is set. What is calculated is known. The stop distance estimation system calculates the idle running distance and braking distance of the vehicle using [Equation 910] and [Equation 920], and stops using [Equation 930] from the calculated idle running distance and braking distance. A distance is calculated, and a speed at which the traveling vehicle can safely stop by a predetermined position is calculated based on the calculated stop distance (see Patent Document 1 below). The idle running distance is a distance traveled by the vehicle driver until it is determined that the brake needs to be applied, the foot is released from the accelerator pedal, the brake pedal is depressed, and the brake starts to work. Further, the braking distance is a distance traveled by the vehicle before the braking starts and the vehicle stops.
However, Dt is the free running distance, Tr is the reaction time from the time when the driver feels danger and the brake is necessary to the time when the brake pedal is depressed and the brake starts to work, and V is the vehicle speed.
However, Db is a braking distance, μ is a friction coefficient, and g is a gravitational acceleration.
However, Ds is a stop distance.

Here, in the stop distance estimation system, the reaction time and the friction coefficient are constants. That is, the reaction time is a typical average value of 0.75 seconds, and the friction coefficient is a constant value determined according to the road surface condition, as shown in Table 900.

JP 2005-346333 A (pages 18 to 19)

  However, the value of the reaction time in the above conventional stop distance estimation system is actually a value determined individually according to the gender and age of the driver, driving skill, speed of reaction feeling, physical condition, etc. It is a value that changes for each vehicle to be measured, not the value of.

  In addition, the value of the friction coefficient is not only the vehicle type and structure, or the vehicle conditions such as loading weight, brake performance, tire wear, etc., but also the road surface such as road surface gradient, unevenness, old and new conditions, etc. Therefore, it is practically impossible to determine a certain value for the vehicle to be measured.

  Furthermore, a vehicle that is actually running does not decelerate with a sufficient braking force as soon as the driver performs a braking operation that depresses the brake. When the brake is depressed, the braking force gradually increases. The vehicle is finally decelerated by obtaining a sufficient braking force, that is, the braking behavior of a vehicle that is actually running is moderately decelerated. The actual braking behavior is not considered at all.

  For these reasons, in the conventional stopping distance estimation system, many errors are included in the calculated idle running distance and braking distance, and therefore the stopping distance cannot be calculated with high accuracy. .

  Therefore, the present invention has been made in view of the above problems, and provides a stop distance estimation system capable of accurately calculating a stop distance and a method for calculating and estimating a stop distance using the stop distance estimation system. Let it be an issue.

The present invention has been made to solve the above-described problem, and a stop distance estimation system according to the present invention is based on a measurement unit that measures a speed of a measurement object for a predetermined time, and a measurement result of the measurement unit. A control unit that calculates a stop distance until the measurement object stops, and the control unit determines a period during which the measurement unit continuously decelerates for a predetermined period from the speed result measured by the measurement unit. And a deceleration determination unit that determines that the measurement object is decelerating, an initial speed setting unit that sets a measurement speed at the start of deceleration in the deceleration determination period as an initial speed, and within the deceleration determination period Correction means for correcting [Equation 1] based on an error between the deceleration measurement speed measured in [Equation 1] and the calculated speed calculated from [Equation 1] with reference to the deceleration start time, and measurement acceleration relating to the deceleration measurement speed. Determining means for determining the deceleration rate and time constant based on the difference based on the degree and the calculated acceleration relating to the calculated speed, the formula corrected by the correcting means, and the initial speed set by the initial speed setting means And a deceleration time and a time constant determined by the determination means, a stop time calculation means for calculating a time from the start of deceleration until the measurement object stops as a stop time, and a measurement object from the start of deceleration And a stop distance calculating means for calculating from [Equation 2] using the distance traveled by the measurement object before the object stops as a stop distance.
However, v is a calculated speed, v ₀ is an initial speed, μg is a deceleration rate, t is a deceleration time that is elapsed from the start of deceleration, and τ is a time constant.
However, d _s is a stop distance and t _s is a stop time.

  In the stop distance estimation system having such a configuration, the correcting means corrects [Equation 1] based on the error between the deceleration measurement speed and the calculated speed, and the determining means is based on the difference between the measured acceleration and the calculated acceleration. Since the deceleration rate and time constant are determined, the values of the speed, deceleration rate, and time constant calculated from the corrected formula should be the values corresponding to the braking behavior of the actual measurement object. Can do. And since the stop time calculation means calculates the stop time using the corrected mathematical formula, the deceleration rate, and the time constant, it is possible to calculate the stop time with a small error. Therefore, the stop distance calculating means applies the deceleration rate and time constant corresponding to the braking behavior of the measurement object, and the stop time with a small error to [Equation 2] for calculating the stop distance, thereby reducing the error. An accurate stopping distance can be calculated.

  In particular, it is preferable that the correction unit correct [Equation 1] so that an error between the deceleration measurement speed and the calculated speed becomes zero.

  Further, it is preferable that the determining means determines the deceleration rate and the time constant so that an absolute value of a difference between the deceleration measurement acceleration and the calculated acceleration becomes a minimum value.

  Further, the deceleration measurement speed is measured every predetermined measurement time within the deceleration judgment period, and the calculated speed is calculated every measurement time so as to correspond to each of the deceleration measurement speeds. The correction means calculates an error between the deceleration measurement speed and the calculated speed corresponding to each other, and corrects [Equation 1] so that the average value of the calculated errors becomes zero. preferable.

  Furthermore, the deceleration measurement speed is measured every predetermined measurement time within a deceleration determination period, and the calculated speed is calculated every measurement time so as to correspond to each of the deceleration measurement speeds. The determining means measures, for each section corresponding to the measurement time, the acceleration in the section using the deceleration measurement speed in the section and the deceleration measurement speed measured immediately before the deceleration measurement speed. For each section corresponding to the measurement time, the acceleration in the section is calculated as the calculated acceleration using the calculated speed in the section and the calculated speed calculated immediately before the calculated speed for each section corresponding to the measurement time. In each section, the absolute value of the difference between the measured acceleration and the calculated acceleration corresponding to each other is calculated, and the deceleration rate and the time constant are determined so that the sum of the calculated absolute values becomes the minimum value. thing Preferred.

In addition, the method according to the present invention includes a measurement unit that measures the speed of the measurement object for a predetermined time, and a control unit that calculates a stop distance until the measurement object stops based on a measurement result of the measurement unit. A method for calculating and estimating the stop distance using a stop distance estimation system provided, wherein the control unit is configured to calculate a period during which the speed is continuously decelerated for a predetermined period from the speed result measured by the measuring unit for a predetermined time. Recognizing that the measurement target is decelerating by recognizing a deceleration determination period, setting a measurement speed at the start of deceleration in the deceleration determination period as an initial speed, and measuring within the deceleration determination period Correcting [Equation 1] based on an error between the calculated deceleration measurement speed and the calculated speed calculated from [Equation 1] with reference to the deceleration start time, and measurement related to the deceleration measurement speed A step of determining the deceleration rate and a time constant based on a difference based on a velocity and a calculated acceleration relating to the calculated velocity, a corrected mathematical formula in the correcting step, the initial velocity, the determined deceleration rate, and Using the time constant, the step of calculating the time from the start of deceleration until the measurement object stops as the stop time, and the measurement object moves between the start of deceleration and the measurement object stops And a step of calculating from [Equation 2] using the distance to be stopped as a stop distance.
However, v is a calculated speed, v ₀ is an initial speed, μg is a deceleration rate, t is a deceleration time that is elapsed from the start of deceleration, and τ is a time constant.
However, d _s is a stop distance and t _s is a stop time.

  Thus, in the stop distance estimation system according to the present invention and the method for calculating and estimating the stop distance using the stop distance estimation system, the correcting means is based on the error between the deceleration measurement speed and the calculated speed. [Equation 1] is corrected, the determining means determines the deceleration rate and the time constant based on the difference between the measured acceleration and the calculated acceleration, and the stop time calculating unit is configured to correct the corrected mathematical formula, the deceleration rate and the time constant. Because the stop time is calculated using and, the values of the speed, deceleration rate and time constant calculated from the corrected mathematical formula can be set to values corresponding to the braking behavior of the actually measured object. As a result, the stop distance calculation means calculates the stop distance based on the deceleration rate and time constant corresponding to the braking behavior of the measurement object, and the stop time with a small error. For [Equation 2] Advantageously possible error is calculated good stopping distance of less accurate Te.

It is the schematic which shows 1st embodiment of the stop distance estimation system which concerns on this invention. It is a block diagram which shows the structure of the stop distance estimation system. It is a flowchart which shows the stop distance calculation procedure by the stop distance estimation system. It is the schematic which shows 2nd embodiment of the stop distance estimation system which concerns on this invention. It is a block diagram which shows the structure of the stop distance estimation system. It is a flowchart which shows the stop position judgment procedure by the stop distance estimation system.

Hereinafter, a first embodiment of a stop distance estimation system and a method for calculating and estimating a stop distance according to the present invention will be described in detail with reference to the drawings.
1 and 2 show a stop distance estimation system 1 according to the first embodiment. The stop distance estimation system 1 measures, for example, the speed of the vehicle P as a measurement object that is running, and calculates the stop distance from when the brake of the vehicle P starts to work until it stops based on the measurement result. A measuring unit 10 that measures a measured speed as a speed of the vehicle P for a predetermined time, and calculates a stop distance until the vehicle P stops based on a measurement result of the measuring unit 10 And a control unit 20 for performing the above operation.

  The measuring means 10 continuously transmits a transmission wave toward the vehicle P, receives the reflected wave reflected by the vehicle P as a reception wave, and based on the reception wave received by the transmission / reception means 110. The calculation unit 120 is configured to calculate the measurement speed and store the measurement speed in a measurement order, for example, in a memory (not shown) or the like so that the measurement speeds are arranged in the order of measurement.

  The transmission / reception means 110 transmits the signal wave generated by the signal source 111 and the signal wave generated by the signal source 111 toward the vehicle P as a transmission wave, and the reflected wave reflected by the vehicle P as a reception wave. And an antenna 112 for reception. The transmission / reception unit 110 is configured to sequentially input received reception waves to the calculation unit 120. In the first embodiment, the received reception waves are amplified by a power detector 113 as an amplifier and operated. It is configured to sequentially input to the means 120.

  The calculating means 120 is configured to calculate a measurement speed based on received waves that are sequentially input, and store the calculated measurement speed in the order of measurement so as to be arranged in the order of measurement. In the first embodiment, the measurement speed is measured every predetermined measurement time. Specifically, the measurement speed is calculated and stored by the calculation means 120 every predetermined measurement time. ing. Moreover, although the calculation means 120 is provided in the control part 20, it is not restricted to this, For example, you may incorporate in the transmission / reception means 110. FIG.

  The control unit 20 includes a speed comparison unit 201 that compares the measurement speed sequentially measured by the measurement unit 10 with the measurement speed measured immediately before the measurement unit 10, and the speed result measured for a predetermined time by the measurement unit 10 for a predetermined period. The vehicle is provided with deceleration determination means 202 that determines that the vehicle P is decelerating by recognizing the deceleration period as the deceleration determination period.

  The speed comparison means 201 is configured to compare the measurement speed measured this time with the measurement speed measured last time in order from the measurement speed measured for each measurement speed measured by the measurement means 10. ing. Specifically, the speed comparison means 201 is configured to compare the latest (last) measurement speed stored by the calculation means 120 with the measurement speed stored immediately before.

  The deceleration determination unit 202 is configured to determine whether the vehicle P is decelerating based on the comparison result of the speed comparison unit 201. Specifically, the deceleration determination unit 202 is configured to determine whether or not the measurement speed measured this time is smaller than the measurement speed measured last time based on the comparison made in the measurement order by the speed comparison unit 201. When the measurement speed measured this time is smaller than the measurement speed measured last time, the period is recognized as a deceleration determination period, and the vehicle P related to the measurement decelerates. It is comprised so that it may be judged.

  More specifically, as a result of comparison by the speed comparison unit 201, the deceleration determination unit 202 determines that the latest measurement speed stored by the calculation unit 120 is smaller than the measurement speed stored immediately before that, that is, When the velocity gradient is negative, it is configured to add a flag to the latest memorized speed. As a result of repeating such a process several times in succession, the latest memorized in all the processes. When the measured speed is flagged, that is, when the state where the speed gradient is negative continues for a predetermined period, this period is recognized as a deceleration determination period and is determined to be deceleration. Yes. When the deceleration determination period is recognized by the deceleration determination unit 202, the plurality of measurement speeds measured for each measurement time within the deceleration determination period are the plurality of decelerations measured for each measurement time within the deceleration determination period. Recognized as measurement speed.

In addition, the control unit 20 sets initial speed setting means 203 that sets the measured speed at the start of deceleration in the deceleration determination period as the initial measurement speed, the measured deceleration speed measured within the deceleration determination period, and the deceleration start. Based on a correction unit 204 that corrects [Equation 1] based on an error from the calculated speed calculated from [Equation 1] with respect to time, and a difference based on a measured acceleration related to the deceleration measurement speed and a calculated acceleration related to the calculated speed. Determining means 205 for determining the deceleration rate and time constant, the formula corrected by the correcting means 204, the initial measurement speed set by the initial speed setting means, the deceleration rate and time constant determined by the determining means 205, To stop time calculation means 206 for calculating the time from the start of deceleration until the vehicle P stops as a stop time, and until the vehicle P stops from the start of deceleration. And a stopping distance calculation means 207 that the vehicle P is calculated from Equation 2 the distance traveled as a stop distance between.
However, v is a calculated speed, v ₀ is an initial speed, μg is a deceleration rate, t is a deceleration time that is elapsed from the start of deceleration, and τ is a time constant.
However, d _s is a stop distance and t _s is a stop time.

  The initial speed setting means 203 is the first of the measured deceleration speeds measured during the deceleration determination period recognized by the deceleration determination means 202 when the deceleration determination means 202 determines that the vehicle P is decelerating. The measured deceleration measurement speed is set as the initial measurement speed. Specifically, when the deceleration determination unit 202 determines that the vehicle P is decelerating, the initial speed setting unit 203 determines that the currently measured deceleration measurement speed is less than the previously measured deceleration measurement speed during the deceleration determination period. The first time point when the value becomes smaller is determined, and the previously measured deceleration measurement speed at this time point is set and stored as the initial measurement speed.

  More specifically, when the initial speed setting unit 203 determines that the vehicle P is decelerating, the initial speed setting unit 203 includes a plurality of fragments that are assigned in order for each measurement time in the deceleration determination period by the deceleration determination unit 202. Going back in the reverse order from the order given to the fragment at the time when it was determined that the vehicle was decelerating, the deceleration measurement speed at the time when the first fragment was attached was calculated, and the calculated deceleration measurement speed was calculated. The deceleration measurement speed stored immediately before is calculated, and this is set as the initial measurement speed and stored. In the first embodiment, when the initial speed setting unit 203 sets the initial measurement speed, the initial speed setting unit 203 outputs a determination command to the determination unit 205 so as to determine the deceleration rate and the time constant. It is configured.

  Based on the speed error as an error relating to the deceleration measurement speed measured within the deceleration determination period and the calculated speed calculated from [Equation 1] with reference to the deceleration start time, [Equation 1] Is configured to correct [Equation 1] so that the speed error is zero. Specifically, the correction unit 204 corrects [Expression 1] using a speed error based on the difference between the deceleration measurement speed and the calculated speed corresponding to each other so that the average value of the speed errors becomes zero. It is configured as follows.

  The calculated speed is calculated for each measurement time within the deceleration determination period so as to correspond to each deceleration measurement speed. That is, the calculated speed is calculated every time the measurement time elapses from the start of deceleration, and the calculated timing is the same as the timing for measuring the deceleration measurement speed. In the present embodiment, the calculation speed is calculated from [Equation 3] obtained by converting [Equation 1].

In the present embodiment, the correction unit 204 converts [Equation 1] using t = jΔt (j = 0, 1, 2,..., N), x = μgΔt, and z = Δt / τ. [Equation 3] is corrected to a formula that takes into account the speed error. Specifically, the calculated initial speed v (0) of [Equation 3] is corrected in consideration of the speed error. It is configured. Here, j represents the number of measurements, and Δt represents the measurement time. Further, x indicates the amount of deceleration that decelerates during the measurement time Δt, and z is a coefficient that indicates the degree of time delay per unit time.
However, v (jΔt) is the calculated speed and v (0) is the calculated initial speed.

More specifically, the correction unit 204 first converts [Equation 1] into [Equation 3]. Then, using [Equation 3] and [Equation 4] representing the deceleration measurement speed using the calculated speed and the speed error, as shown in [Equation 5], the deceleration measurement speed for each measurement time is set respectively. Calculate.
However, v _j is a deceleration measurement speed and Δv _j is a speed error.

Then, from v ₀ = v (0) + Δv ₀ of [Equation 5], v (0) = v ₀ −Δv ₀ is set, and this equation is substituted into another equation of [Equation 5] to calculate [Equation 6]. To do.

Then, y _j0 = Δv _j −Δv ₀ is set, and this expression is substituted into [Expression 6] to calculate [Expression 7] that is an expression of x. Y _j0 is a mathematical expression related to the difference in speed error between the deceleration measurement speed and the calculated speed. Specifically, the initial speed error Δv ₀ between the initial measurement speed and the calculated initial speed and the deceleration measurement measured at the jth time. It is a mathematical formula showing the difference between the speed and the calculated speed error Δv _j .

Then, using [Equation 7], [Equation 8] respectively representing y ₁₀ to y _{(n−1) 0} is calculated. Specifically, y ₁₀ is calculated using the first expression and the nth expression of [Equation 7], y ₂₀ is calculated using the second expression and the nth expression, and such calculation is continued. Y _{(n-1) 0} is calculated.

Here, the correction means 204 assumes that y _n0 = 0, and [Formula 9] which is an equation indicating that the sum of the speed errors as an average value of the speed errors is zero.

Then, [Equation 9] is modified so that Δv ₀ −Δv ₀ + Δv ₁ −Δv ₀ +... + Δv _n −Δv ₀ + (n + 1) Δv ₀ = y ₁₀ + y ₂₀ +... + Y _n0 + (n + 1 ) Δv ₀ = 0, and [Expression 10], which is an equation indicating the initial speed error, is calculated.

Finally, the correction unit 204 substitutes [Equation 10] and v (0) = v ₀ −Δv ₀ obtained from [Equation 5] into [Equation 3], and takes into account the speed error, [Equation 11] which is a mathematical formula obtained by correcting [3] is calculated.

In this way, the correction unit 204 represents the calculated initial speed v (0) of [Equation 3] as a speed error Δv ₀ so that the speed calculation formula for calculating the speed is a formula that takes the speed error into account. Thus, [Equation 11] is obtained.

  The determining means 205 is configured to determine a deceleration rate and a time constant based on an acceleration error as a difference based on a measured acceleration related to a deceleration measured speed and a calculated acceleration related to the calculated speed, and based on the acceleration error The deceleration rate and the time constant are determined so that the absolute value becomes the minimum value.

  Specifically, for each section corresponding to the measurement time, the determination unit 205 uses the deceleration measurement speed in the section and the deceleration measurement speed measured immediately before the deceleration measurement speed to determine the acceleration in the section. As the measured acceleration, and for each section, the acceleration in the section is calculated as the calculated acceleration using the calculated speed in the section and the calculated speed immediately before the calculated speed. , The absolute value of the acceleration error that is the difference between the measured acceleration and the calculated acceleration corresponding to each other is calculated, and the deceleration rate and the time constant are determined so that the total sum of the calculated absolute values becomes the minimum value. Is configured to do.

More specifically, the determination unit 205 calculates an acceleration error for each section corresponding to the measurement time using [Equation 12]. In [Equation 12], [v ((j−1) Δt) −v (jΔt)] / Δt represents the calculated acceleration, and (v _j−1 −v _j ) / Δt represents the measured acceleration. Further, the acceleration error expressed by [Equation 12] is equal to the difference in inclination for each section.

Then, [Equation 4] is substituted into [Equation 12] to obtain [Equation 13], and y _j0 = Δv _j −Δv ₀ is further substituted into [Equation 13] to _determine the acceleration error and the difference between the speed errors. [Equation 14] expressed as follows.

Then, the determination unit 205 uses [Numerical equation 15] indicating the total sum of absolute values of acceleration errors, that is, the average value of the sum of the squares of the acceleration errors for each section corresponding to the measurement time. Z is calculated so as to be the minimum value.
Finally, the determining unit 205 obtains x from v _n = Δv _n + v ₀ −Δv ₀ −x [n− (1−e ^−nz ) / z] of [Expression 6] using the obtained z.

The stop time calculating means 206 uses [Formula 11], which is a mathematical expression corrected by the correcting means 204, to stop the vehicle from the time when the vehicle stops, that is, from the time when the initial speed is measured. The time until is calculated as the stop time. Specifically, the stop time calculation unit 206 includes [Expression 11], x based on the measured initial speed v ₀ that is the initial speed set by the initial speed setting unit, and the deceleration rate determined by the determination unit 205 and x and z based on the time constant, is used to calculate the stop time t _s. Specifically, v ₀ , x, and z are substituted into [Equation 11], and the calculation speed is v (jΔt) = 0, and the stop time t _s = nΔt is calculated.

The stop distance calculating means 207 determines the distance that the measurement object moves from the time when the deceleration starts until the measurement object stops, that is, the distance from when the initial speed is measured until the vehicle stops. Is calculated as a stop distance. Specifically, the stop distance calculating unit 207 is configured to calculate the stop distance using the stop distance calculating formula [Expression 2] obtained based on the speed calculating expression [Expression 1] to which the first-order lag system is added. are, in the present embodiment, the measurement and the initial velocity v _0, the deceleration degree μg obtained from x, and a constant τ when the calculated a-z, stopping distance d _s by substituting the stop time t _s in Equation 2 It is comprised so that it may calculate.

  Next, a method for calculating the stop distance using the stop distance estimation system 1 having the above configuration will be described with reference to the flowchart shown in FIG.

  First, when the stop distance calculation method starts, the measurement means 10 measures the measurement speed, which is the speed of the vehicle P, which is the measurement object, for each predetermined measurement time (step S1). Specifically, the transmission / reception unit 110 continuously transmits a transmission wave toward the vehicle P, receives the reflected wave reflected by the vehicle P as a reception wave, and receives the reception wave as the calculation unit 120 of the control unit 20. Enter sequentially. Then, every time the measurement time elapses, the calculation means 120 calculates the measurement speed, which is the speed of the vehicle P, based on the received waves that are sequentially input, and measures the calculated measurement speeds so that they are arranged in the order of measurement. For example, the data is stored in a memory or the like.

  Next, the deceleration determination unit 202 determines that the vehicle P is decelerating by recognizing a period during which the speed is continuously decelerated for a predetermined period from the speed result measured by the measurement unit 10 as a deceleration determination period. (Step S2). Specifically, the measurement speed measured this time and the measurement speed measured last time are sequentially measured from the measurement speed measured by the speed comparison means 201 at every predetermined measurement time by the measurement means 10. And compare. Then, based on the comparison made in the order of measurement, the deceleration determination means 202 determines whether or not the measurement speed measured this time is smaller than the measurement speed measured last time, and the measurement speed measured this time was measured last time. When results smaller than the measurement speed are obtained continuously for a predetermined period, the period is recognized as a deceleration determination period, and it is determined that the vehicle P for measurement is decelerating.

  More specifically, among the measurement speeds stored in the order of measurement by the speed comparison unit 201, the latest stored measurement speed (the last stored measurement speed) and the measurement speed stored immediately before it are calculated. Compare. Then, when the latest measurement speed is smaller than the measurement speed stored immediately before, that is, when the speed gradient is negative, the deceleration determination means 202 adds a flag to the latest speed. If this process is repeated several times in succession and all the processes are flagged, that is, if the state where the speed gradient is negative lasts for a predetermined period, this period is recognized as the deceleration judgment period. Judged as deceleration. That is, in step S2, when the state where the speed gradient is negative among the speed results measured by the measuring unit 10 for a predetermined time continues continuously for a predetermined period by the deceleration determining unit 202, the period is determined to be decelerated. By recognizing the period, it is determined that the vehicle P is decelerating. When the deceleration determination period is recognized by the deceleration determination unit 202, the plurality of measurement speeds measured for each measurement time within the deceleration determination period are the plurality of decelerations measured for each measurement time within the deceleration determination period. Recognized as measurement speed.

  If it is determined by the deceleration determination means 202 that the vehicle P is decelerating, the initial speed setting means 203 sets the speed of the vehicle P at the start of deceleration during the deceleration determination period as the initial speed (step S3). Specifically, when it is determined in step S2 that the vehicle P is decelerating, the initial speed setting means 203 makes the currently measured deceleration measurement speed smaller than the previously measured deceleration measurement speed during the deceleration determination period. The deceleration measurement speed immediately before the first time is set and stored as the initial measurement speed. More specifically, when it is determined that the vehicle P is decelerating, the initial speed setting means 203 determines that the plurality of fragments that are sequentially assigned in the deceleration determination period are decelerated. Go back from the flag in order to reverse the order in which the flags were attached, and calculate the deceleration measurement speed at the time of the first attachment, immediately before the calculated deceleration measurement speed. The stored deceleration measurement speed is calculated, and this is set as the initial measurement speed and stored. When the initial measurement speed is set, the initial speed setting means 203 outputs a determination command to the determination means 205 so as to determine the deceleration rate and the time constant.

  Next, based on the speed error as an error related to the deceleration measurement speed measured within the deceleration determination period by the correction unit 204 and the calculated speed calculated from [Equation 1] with reference to the deceleration start time, [ Equation 1] is corrected (step S4). Specifically, the speed error is set to 0 by the correction unit 204, that is, using the speed error based on the difference between the deceleration measurement speed and the calculated speed corresponding to each other, the average value of the speed error is 0. [Equation 1] is corrected so that

  In this embodiment, the correction unit 204 converts [Equation 1] using t = jΔt (j = 0, 1, 2,..., N), x = μgΔt, and z = Δt / τ. The mathematical expression considering the speed error, that is, the calculated initial speed v (0) of [Mathematical formula 3] is corrected in consideration of the speed error.

  More specifically, in step S4, the correction unit 204 converts [Equation 1] into [Equation 3], and expresses the deceleration measurement speed using the [Equation 3], the calculated speed, and the speed error [ Using [Equation 4], the deceleration measurement speed for each measurement time is calculated, as shown in [Equation 5].

Then, v (0) = v ₀ −Δv ₀ is calculated from [Equation 5], and this equation is substituted for another equation in [Equation 5] to calculate [Equation 6].

Then, y _j0 = Δv _j −Δv ₀ is set, and this expression is substituted into [Expression 6] to calculate [Expression 7] that is an expression of x.

Then, using [Equation 7], [Equation 8] respectively representing y ₁₀ to y _{(n−1) 0} is calculated. Specifically, y ₁₀ is calculated using the first expression and the nth expression of [Equation 7], y ₂₀ is calculated using the second expression and the nth expression, and such calculation is continued. Y _{(n-1) 0} is calculated.

Here, it is assumed that y _n0 = 0, and [Formula 9] is an equation indicating that the sum of speed errors as an average value of speed errors is zero.

Then, [Equation 9] is modified so that Δv ₀ −Δv ₀ + Δv ₁ −Δv ₀ +... + Δv _n −Δv ₀ + (n + 1) Δv ₀ = y ₁₀ + y ₂₀ +... + Y _n0 + (n + 1 ) Δv ₀ = 0, and [Expression 10], which is an equation indicating the initial speed error, is calculated.

Then, [Expression 10] and v (0) = v ₀ −Δv ₀ obtained from [Expression ₅ ] are substituted into [Expression 3], and [Expression 3] is corrected in consideration of the speed error. [Equation 11] is calculated (step S41).

  Then, it is checked whether [Equation 11] is calculated in step S41 (step S42).

In this manner, in step S4, the calculated initial speed v (0) of [Equation 3] is calculated as the speed error so that the speed calculation formula for calculating the speed by the correcting unit 204 is a formula that takes the speed error into consideration. [Expression 11] is calculated by correcting it by Δv ₀ (step S41), and it is confirmed whether correction has been made, that is, whether [expression 11] has been calculated (step S42).

  Next, the determining means 205 determines the deceleration rate and the time constant based on the acceleration error based on the measured acceleration related to the deceleration measured speed and the calculated acceleration related to the calculated speed (step S5). In the present embodiment, the determining means 205 determines the absolute value based on the acceleration error to be the minimum value, that is, the deceleration rate and the time constant as described above.

  Specifically, for each section corresponding to the measurement time, the determination unit 205 uses the deceleration measurement speed in the section and the deceleration measurement speed measured immediately before the deceleration measurement speed to determine the acceleration in the section. Is calculated as a measured acceleration (step S51), and for each of the sections, the acceleration in the section is calculated as the calculated acceleration using the calculated speed in the section and the calculated speed immediately before the calculated speed. (Step S52) In each section, the absolute value of the acceleration error that is the difference between the measured acceleration and the calculated acceleration corresponding to each other is calculated (Step S53), and the sum of the calculated absolute values becomes the minimum value. Thus, the deceleration rate and the time constant are determined (steps S54 to S57).

More specifically, in step S5, the measured acceleration, calculated acceleration, and acceleration error are calculated using [Equation 12] (steps S51 to S53). Then, [Equation 4] is substituted into [Equation 12] to obtain [Equation 13], and y _j0 = Δv _j −Δv ₀ is further substituted into [Equation 13] to _determine the acceleration error and the difference between the speed errors. [Equation 14] expressed by the following equation, and further using [Equation 15] indicating the total sum of the absolute values of acceleration errors, that is, the average value of the sum of the squares of the acceleration errors for each section corresponding to the measurement time, Z is calculated so that [Equation 15] becomes the minimum value (step S54).

Then, it is confirmed whether or not the calculation in step S54 has been performed, that is, whether or not z has been calculated (step S55). If z has been calculated, the obtained z is used to calculate [Equation 6]. V _n = Δv _n + v ₀ −Δv ₀ −x [n− (1−e ^−nz ) / z] is obtained (step S56), and it is confirmed whether or not x is obtained in step S56 (step S56). S57).

Next, the stop time calculation means 206 uses [Equation 11] to calculate the time from the start of deceleration until the vehicle stops, that is, the time from when the measurement initial speed is measured until the vehicle stops. (Step S6). Specifically, the initial measurement speed v ₀ set by the initial speed setting means, x based on the deceleration degree determined by the determination means 205, and z based on the time constant are respectively substituted into [Equation 11]. The calculation time is v (jΔt) = 0 and the stop time t _s = nΔt is calculated.

Finally, the distance traveled by the stop distance calculating means 207 from the start of deceleration to the stop of the vehicle P is defined as the stop distance, that is, from the time when the measurement initial speed is measured until the stop of the vehicle. The distance traveled by the vehicle is calculated as a stop distance (step S7). Specifically, it calculates the measured initial velocity v _0, the deceleration degree μg obtained from x, and a constant τ when the calculated a-z, the stopping distance d _s by substituting the stop time t _s in Equation 2.

  Next, a second embodiment according to the present invention will be described with reference to FIGS. In addition, about the structure and procedure (step) which are common in 1st embodiment, suppose that the same code | symbol as 1st embodiment is attached | subjected, and the description is abbreviate | omitted.

  4 and 5 show a stop distance estimation system 1 according to the second embodiment. The stop distance estimation system 1 can determine the stop position of the vehicle P by measuring the speed of the vehicle P as the measurement object and the distance to the vehicle P as the position of the vehicle P from the road shoulder. System.

  The stop distance estimation system 1 includes a measuring unit 10 that measures a speed of the vehicle P and a distance to the vehicle P for a predetermined time, and a stop distance until the vehicle P stops based on a measurement result of the measuring unit 10. The controller 20 that calculates and determines the position where the vehicle P stops based on the calculated stop distance, and when it is determined that the determined stop position exceeds the reference position, the controller 20 stops exceeding the reference position. And a notification means 30 that operates to notify. In the second embodiment, the stop distance estimation system 1 can determine whether or not the vehicle P traveling toward the intersection stops beyond the stop line Y before the intersection as the reference position. It can be done.

  Specifically, the control unit 20 has the same configuration as that of the first embodiment, and further, a stop position index that calculates a position where the vehicle P stops based on the stop distance calculated by the stop distance calculation unit 207. Means 208 and stop position judging means 209 for judging whether or not the determined stop position exceeds a stop line Y as a reference position.

  The stop position indexing means 208 is based on the position of the vehicle P at the start of deceleration based on the position of the vehicle P at the start of deceleration in the deceleration determination period and the stop distance calculated by the stop distance calculating means 207. The stop position of the vehicle P is determined.

  The stop position determining means 209 determines whether or not the stop position exceeds the stop line Y by calculating the distance between the stop position indexed by the stop position indexing means 208 and the stop line Y. It is configured. Specifically, the stop position determination unit 209 compares the distance to the vehicle P at the stop position calculated by the stop position indexing unit 208 with the distance to the stop line Y, and determines the distance to the vehicle P at the stop position. When the distance is larger (far) than the distance to the stop line Y, it is determined that the determined stop position does not exceed the stop line Y, that is, the vehicle P stops before the stop line Y, and is small (close). In this case, it is determined that the determined stop position exceeds the stop line Y, that is, the vehicle P stops beyond the stop line Y. The stop position determination unit 209 is configured to output an operation command to the notification unit 30 when it is determined that the stop position exceeds the stop line Y.

  When the stop position determination unit 209 determines that the stop position exceeds the stop line Y, the notification unit 30 is configured to operate to notify that the stop position exceeds the stop line Y. Specifically, the notification unit 30 is, for example, an indicator lamp or a siren. Upon receiving an operation command from the stop position determination unit 209, the notification unit 30 emits light or sound to the surroundings or to the driver of the vehicle P. Thus, it is configured to notify that the stop position of the vehicle P exceeds the stop line Y.

  Next, a method for determining whether or not the stop position of the vehicle P exceeds the stop line Y using the stop distance estimation system 1 configured as described above will be described with reference to the flowchart shown in FIG. In addition, about the procedure (step S1 thru | or step S7) until calculating the stop distance of the vehicle P, it is the same as that of the procedure of 1st embodiment.

  When the stop distance of the vehicle P is calculated in step S7, the position where the vehicle P stops is determined based on the stop distance calculated by the stop position indexing means 208 (step S8). Specifically, the stop position of the vehicle P is determined by the stop position indexing means 208 based on the position of the vehicle P at the start of deceleration during the deceleration determination period and the stop distance calculated by the stop distance calculating means 207. Index.

  Next, the stop position determination means 209 determines whether or not the determined stop position exceeds a stop line Y as a reference position (step S9). Specifically, the stop position determined in step S8 is compared with the position of the stop line Y as the reference position, and when the stop position is ahead of the stop line Y in the vehicle P traveling direction, When the vehicle P is determined to stop beyond the stop line Y and the stop position is behind the stop line Y in the traveling direction of the vehicle P, it is determined that the vehicle P stops without exceeding the stop line Y. When the stop position determination unit 209 determines that the vehicle P stops beyond the stop line Y, the stop position determination unit 209 outputs an operation command to the notification unit 30. When it is determined that the vehicle P will stop without exceeding the stop line Y, the control is terminated.

  Next, when it is determined that the vehicle P stops beyond the stop line Y, the notification means 30 is activated (step S10). Specifically, an indicator lamp lights up or a siren sounds. Thereby, it can be notified that the vehicle P stops beyond the stop line Y.

  In the stop distance estimation system 1 according to the first and second embodiments as described above and the method for calculating and estimating the stop distance using the stop distance estimation system 1, the correction unit 204 includes the deceleration measurement speed. [Equation 1] is corrected based on the error between the calculated acceleration and the calculation speed, and the determination unit 205 determines the deceleration rate and the time constant based on the difference between the measured acceleration and the calculated acceleration. The values of the calculated speed, deceleration rate, and time constant calculated from [Equation 11] vary depending on the value corresponding to the braking behavior of the vehicle that is actually measured, that is, the situation of the vehicle, the road surface, the driver, etc. Regardless of the friction coefficient and the reaction time, the value can correspond to the gentle braking behavior that occurs in an actual vehicle. Since the stop time calculation means 206 calculates the stop time using [Equation 11], the deceleration rate, and the time constant, it is possible to calculate an accurate stop time with a small error. Therefore, the stop distance calculation means 207 applies the deceleration rate and time constant corresponding to the actual braking behavior of the vehicle, and the stop time with high accuracy to [Equation 2] for calculating the stop distance, and there is an error. A small and accurate stopping distance can be calculated.

  In addition, when determining the deceleration rate and the time constant, the calculation is performed so that the absolute value of the acceleration error is minimized using [Equation 11] corrected in consideration of the speed error. Can be set to a more appropriate value, and the stop distance can be calculated with high accuracy.

  Further, since the calculation means 120 stores the calculated speeds in order of measurement in order, for example, in a memory or the like, the processing efficiency is improved.

  Furthermore, in the stop distance estimation system 1 according to the second embodiment and the method of calculating and estimating the stop distance using the stop distance estimation system 1, the stop distance of the vehicle P calculated accurately is used. Since the positional relationship between the stop position of the vehicle P and the stop line Y as the reference position is determined, the case where the vehicle P stops beyond the stop line Y can be accurately determined and notified. For example, the driver of the vehicle P who has forgotten to stop at the stop line Y can be accurately identified and alerted.

  In the first and second embodiments, the case where the position of the vehicle P is the distance from the measuring means 10 to the vehicle P has been described. However, the present invention is not limited to this, and the position of the vehicle P is set to, for example, a predetermined reference vehicle. The distance from the position to the vehicle P can also be set.

  In the first and second embodiments, the case where the determination step (step S5) by the determination unit 205 is executed after the correction step (step S4) by the correction unit 204 has been described. The correction step and the determination step may be executed at the same time.

  DESCRIPTION OF SYMBOLS 1 ... Stop distance estimation system, 10 ... Measuring means, 20 ... Control part, 30 ... Notification means, 110 ... Transmission / reception means, 111 ... Signal source, 112 ... Antenna, 113 ... Power detector, 120 ... Calculation means, 201 ... Speed comparison Means 202: Deceleration judgment means 203 ... Initial speed setting means 204 ... Correction means 205 ... Determination means 206 ... Stop time calculation means 207 ... Stop distance calculation means 208 ... Stop position indexing means 209 ... Stop Position judging means, P ... vehicle, Y ... stop line

Claims (6)

A measuring unit that measures the speed of the measuring object for a predetermined time; and a control unit that calculates a stop distance until the measuring object stops based on a measurement result of the measuring unit;
The control unit
Deceleration determining means for determining that the measurement object is decelerating by recognizing a period in which the speed is measured continuously for a predetermined time by the measuring means as a deceleration determination period.
Initial speed setting means for setting the measured speed at the start of deceleration during the deceleration determination period as the initial speed;
Correction means for correcting [Equation 1] based on an error between a deceleration measurement speed measured within the deceleration determination period and a calculated speed calculated from [Equation 1] with reference to the deceleration start time;
However, v is a calculated speed, v ₀ is an initial speed, μg is a deceleration rate, t is a deceleration time that is elapsed from the start of deceleration, and τ is a time constant.
Determining means for determining the deceleration rate and the time constant based on a difference based on the measured acceleration related to the deceleration measurement speed and the calculated acceleration related to the calculated speed;
Using the mathematical formula corrected by the correcting means, the initial speed set by the initial speed setting means, the deceleration rate and the time constant determined by the determining means, from the start of deceleration until the measurement object stops. Stop time calculating means for calculating time as stop time;
Stop distance estimation means comprising stop distance calculation means for calculating from [Equation 2] the distance traveled by the measurement object from the start of deceleration until the measurement object stops. system.
However, d _s is a stop distance and t _s is a stop time.   2. The stop distance estimation system according to claim 1, wherein the correction unit corrects [Equation 1] such that an error between the deceleration measurement speed and the calculated speed becomes zero.   3. The stop according to claim 1, wherein the determination unit determines the deceleration rate and the time constant so that an absolute value of a difference between the deceleration measurement acceleration and the calculated acceleration becomes a minimum value. 4. Distance estimation system. The deceleration measurement speed is measured every predetermined measurement time within the deceleration determination period,
The calculated speed is calculated for each measurement time so as to correspond to each of the deceleration measurement speeds,
The correction means calculates an error between a deceleration measurement speed and a calculated speed corresponding to each other, and corrects [Equation 1] so that an average value of the calculated errors becomes zero. The stop distance estimation system according to any one of claims 1 to 3. The deceleration measurement speed is measured every predetermined measurement time within the deceleration determination period,
The calculated speed is calculated for each measurement time so as to correspond to each of the deceleration measurement speeds,
The determination means uses, for each section corresponding to the measurement time, the deceleration measurement speed measured in the section and the deceleration measurement speed measured immediately before the deceleration measurement speed, and the acceleration in the section is used as the measurement acceleration. For each section corresponding to the measurement time, using the calculated speed in the section and the calculated speed calculated immediately before the calculated speed, the acceleration in the section is calculated as the calculated acceleration. Calculating the absolute value of the difference between the measured acceleration and the calculated acceleration corresponding to each other, and determining the deceleration rate and the time constant so that the sum of the calculated absolute values becomes a minimum value. The stop distance estimation system according to any one of claims 1 to 4, wherein Using the stop distance estimation system comprising measuring means for measuring the speed of the measurement object for a predetermined time and a control unit for calculating a stop distance until the measurement object stops based on the measurement result of the measurement means A method for calculating and estimating a stop distance,
The control unit
Determining that the measurement object is decelerating by recognizing a period in which the speed is measured continuously for a predetermined period of time by the measuring means as a deceleration determination period,
Setting a measurement speed at the start of deceleration during the deceleration determination period as an initial speed;
Correcting [Equation 1] based on an error between a deceleration measurement speed measured within the deceleration determination period and a calculated speed calculated from [Equation 1] with the deceleration start time as a reference;
However, v is a calculated speed, v ₀ is an initial speed, μg is a deceleration rate, t is a deceleration time that is elapsed from the start of deceleration, and τ is a time constant.
Determining the deceleration rate and the time constant based on a difference based on the measured acceleration related to the deceleration measurement speed and the calculated acceleration related to the calculated speed;
Using the corrected mathematical formula in the correcting step, the initial speed, the determined deceleration rate and the time constant, calculating a time from the start of deceleration until the measurement object stops as a stop time;
A step of calculating from [Equation 2] as a stop distance a distance traveled by the measurement object from the start of deceleration until the measurement object stops.
However, d _s is a stop distance and t _s is a stop time.