JP2007108071A - On-vehicle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an on-vehicle device where improvement in efficiency and cost reduction of arithmetic processing are achieved. <P>SOLUTION: The on-vehicle device for detecting a vehicle behavior state in a vehicle comprises a position detecting means for detecting the current position of one's own vehicle, a calculating means for calculating a first value showing a behavior state (vehicle speed, yaw rate, or acceleration) based on the hysteresis of the one's own vehicle current position detected by the position detecting means, an output means (vehicle speed sensor, yaw rate sensor, or acceleration sensor) for detecting the behavior state of the one's own vehicle and outputting a second value showing the behavior state, and a determining means for determining a correction factor with respect to the second value output by the output means using the first value calculated by the calculating means. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention generally relates to an in-vehicle device that detects a vehicle behavior state in a vehicle, and more particularly, to an in-vehicle device that achieves higher efficiency and lower cost of arithmetic processing.

  2. Description of the Related Art Conventionally, an in-vehicle device that detects a vehicle behavior state in a vehicle is known (for example, see Patent Document 1).

Patent Document 1 discloses an apparatus that corrects a traveling direction and a current position of a host vehicle detected by an in-vehicle sensor such as an angular velocity sensor using a traveling direction and a current position obtained by using GPS during straight traveling. Has been.
Japanese Patent Laid-Open No. 5-18774

  However, the conventional device disclosed in Patent Document 1 obtains the traveling direction and current position of the vehicle calculated based on the on-vehicle sensor output value from the GPS data on the control device side using these calculated values. It is used after correcting with a value, and does not correct (compensate or calibrate) the in-vehicle sensor itself.

  Therefore, when an error is included in the sensor output value itself due to a failure, individual difference, or the like, correction is required every time in all controls using the output value of the sensor.

  In addition, if each vehicle-mounted sensor is made highly accurate in order to reduce such correction processing as much as possible, the cost increases.

  The present invention has been made to solve such problems, and a main object thereof is to provide an in-vehicle device that realizes efficient calculation processing and low cost.

  One aspect of the present invention for achieving the above object is an in-vehicle device for detecting a vehicle behavior state in a vehicle, the position detecting means for detecting the current position of the host vehicle, and the position detecting means. Calculation means for calculating a first value representing the behavior state of the own vehicle based on the history of the current position of the own vehicle, and output means for detecting the behavior state of the own vehicle and outputting a second value representing the behavior state (For example, a sensor) and a determination unit that determines a correction coefficient for the second value output by the output unit using the first value calculated by the calculation unit.

  In this one aspect, the position detection means detects the current position of the host vehicle using, for example, a GPS (Global Positioning System). Here, it is assumed that a high-accuracy GPS with high (fine) detection accuracy (resolution) such as RTK (Real Time Kinematic) -GPS is used.

  Moreover, in this one aspect | mode, the said behavioral state is a vehicle speed, a yaw rate, or acceleration, for example. In other words, the output means is, for example, a vehicle speed sensor, a yaw rate sensor, or an acceleration sensor.

  According to this aspect, the correction coefficient for the sensor output value is determined using a numerical value representing the vehicle behavior state obtained by using a highly accurate GPS or the like, thereby obtaining a highly accurate sensor output value. Therefore, the demand for the detection accuracy inherent to the sensor hardware itself is lowered, and it is possible to employ a sensor with a lower price.

  Further, according to this aspect, since the output values with high accuracy corrected from each sensor are output, it is not necessary to perform correction processing in various controls using these output values, and the processing efficiency is improved. To do.

  ADVANTAGE OF THE INVENTION According to this invention, the vehicle-mounted apparatus by which the efficiency improvement and cost reduction of arithmetic processing were implement | achieved can be provided.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings. In addition, since the person skilled in the art knows the basic concept, the main hardware configuration, the operating principle, the basic control method, etc. of the in-vehicle device that detects the vehicle behavior state such as the vehicle speed, the yaw rate, or the acceleration, it is detailed. Description is omitted.

  Hereinafter, an in-vehicle device according to an embodiment of the present invention will be described with reference to FIGS. The in-vehicle device 100 according to the present embodiment detects the vehicle speed, yaw rate, or acceleration of a vehicle on which the vehicle is mounted.

  FIG. 1 is a schematic configuration diagram of an in-vehicle device 100 according to the present embodiment.

  The in-vehicle device 100 includes a position detection unit 101 that detects the current position of the host vehicle. In the present embodiment, as an example, the position detection unit 101 detects the current position of the host vehicle using GPS. Here, for example, a high-precision GPS with high (fine) detection accuracy (resolution) such as RTK-GPS is used.

  The in-vehicle device 100 further includes an in-vehicle sensor unit 102 that detects a vehicle behavior state such as a vehicle speed, a yaw rate, or an acceleration. That is, in the present embodiment, the in-vehicle sensor unit 102 is a vehicle speed sensor unit, a yaw rate sensor unit, or an acceleration sensor unit.

  For convenience, only one in-vehicle sensor unit 102 is illustrated in FIG. 1, but the in-vehicle device 100 according to the present embodiment may include a plurality of in-vehicle sensor units 102. In that case, any on-vehicle sensor unit 102 is connected to the position detection unit 101 as shown in FIG.

  The in-vehicle sensor unit 102 includes a detection unit 103 that includes a sensing element that is quantitatively sensitive to a measurement amount, a correction unit 104 that multiplies the output of the detection unit 103 by a correction coefficient and outputs the output as a sensor output value; A correction coefficient determination unit 105 that is a calculation unit that determines the value of the correction coefficient used by the correction unit 104.

  In the in-vehicle device 100 having such a configuration, the correction coefficient determination unit 105 calculates the vehicle speed, yaw rate, or acceleration from the history of the own vehicle position detected by the position detection unit 101, and uses the calculated value and the detection unit 103. By comparing the detection value (vehicle speed, yaw rate, or acceleration) with the correction coefficient (correction unit 104) for the detection value, the vehicle-mounted sensor unit does not depend on the hardware capability (sensing sensitivity) of the detection unit 103. The output value from 102 is assumed to be accurate.

  Next, the flow of correction coefficient determination / update processing in the correction coefficient determination unit 105 will be specifically described with reference to FIGS.

  First, the correction coefficient determination unit 105 acquires GPS data from the position detection unit 101 (S201). Here, the GPS data includes at least the own vehicle position coordinate P (X, Y) periodically detected by the position detection unit 101, the detection time t, and error circle information. The error circle is a circle representing a range of errors that can be included in the detected position information. Mainly, how many GPS satellites the position detection unit 101 can receive data from and the GPS satellites when the data is received Is determined depending on the angle (elevation angle).

  In the present embodiment, as an example, the position detection unit 101 passes the correction data determination unit 105 every time GPS data is detected.

  Next, the correction coefficient determination unit 105 determines whether or not the error circle transmitted from the position detection unit 101 is less than the predetermined allowable error circle TH1 (S202).

  When the error circle is within the allowable error circle TH1 (“YES” in S202), the correction coefficient determination unit 105 buffers the GPS data (S203).

  On the other hand, when the error circle is equal to or larger than the allowable error circle TH1 (“NO” in S202), the correction coefficient determination unit 105 discards the GPS data without buffering.

  An example of the determination in S202 is shown in FIG. In FIG. 3, as an example, it is assumed that GPS data is detected at four positions P1 to P4. In the figure, the solid circle represents the actual error circle, and the broken circle represents the allowable error circle TH1. Here, since the position detection unit 101 periodically detects GPS data, the time intervals of the positions P1 to P4 are equal.

  In the example shown in FIG. 3, since the actual error circle exceeds the allowable error circle TH1 at the position P3, the GPS data detected at the position P3 is discarded, and the correction coefficient determination unit 105 performs the positions P1, P2 , And only GPS data in P4 will be buffered.

  Returning to the description of FIG. As a result of the error circle determination in S202, if it is determined that it can be used to determine the correction coefficient and GPS data is buffered (S203), then the correction coefficient determination unit 105 lastly stores the GPS data buffered this time and the last It is determined whether or not the time interval with the buffered GPS data exceeds a predetermined time TH2 (S204).

  If the time interval exceeds the predetermined time TH2 (“YES” in S204), it is determined that the accuracy of correction coefficient calculation may be deteriorated because the difference in detection time between data is too empty. Then, all the GPS data buffered so far is cleared (S207), and the buffer is restarted from zero.

  If the time interval between the GPS data buffered this time and the GPS data buffered last time is equal to or shorter than the predetermined time TH2 ("NO" in S204), then the correction coefficient determination unit 105 is buffered. It is determined whether or not the number of GPS data exceeds a predetermined value TH3 (S205).

  When the number of GPS data buffered is equal to or smaller than the predetermined value TH3 (“NO” in S205), it is determined that the number of samples is insufficient, and the process returns to S201.

  On the other hand, if the number of buffered GPS data exceeds the predetermined value TH3 (“YES” in S205), then the correction coefficient determination unit 105 determines that a sufficient number of samples have been collected, and so far. The correction unit 104 determines the correction coefficient to be multiplied by the output of the detection unit 103 using the buffered GPS data, and overwrites the correction coefficient held in the correction unit 104 to update (S206).

The process in S206 will be described in detail with reference to FIG. FIG. 4 shows, as an example, GPS data at positions P _n , P _{n + 1} and P _{n + 2} buffered as a result of error circle determination. X / Y is a coordinate value on the XY plane, and t is a detection time.

In addition, here, as an example, a point Q that defines a calculated value is an intermediate point of the vehicle position P here. That is, the middle between the position P _n and the position P _{n + 1} is Q _n , the middle between the position P _{n + 1} and the position P _{n + 2} is Q _{n + 1,} and so on.

  First, the correction coefficient determination unit 105 calculates the vehicle speed V, the yaw rate YR, or the acceleration ACC from the GPS data according to the sensor type of the in-vehicle sensor unit.

For example, the vehicle speed _{V n} between the position _{P n ~P} n _{+ 1} may be determined by using the Pythagorean theorem, differentiating the distance between the position _{P n ~P} n _{+ 1} times,

と表すことができる。

It can be expressed as.

Similarly, the acceleration ACC _n between the positions P _{n to} P _{n + 1} can be obtained by further differentiating the vehicle speed V _n with respect to time,

と表すことができる。

It can be expressed as.

Further, the yaw rate YR _n between the positions _P n _{to P n + 1} may be determined by differentiating the change to the tangential angle theta _{n + 1} at the position _{P n + 1} from the tangent angle theta _n at position _{P n} times,

と表すことができる。

It can be expressed as.

Thus, when the vehicle speed, yaw rate, or acceleration is calculated from the GPS data according to the sensor type of the in-vehicle sensor unit 102, the correction coefficient determination unit 105 sets the calculated value as a true value.
(Calculated value from GPS data) = correction coefficient α × (detected value by detecting unit 103)
A correction coefficient α is determined.

  When the correction coefficient α is determined in this way, the correction coefficient determination unit 105 overwrites and saves the new correction coefficient in the correction unit 104, and the correction unit 104 thereafter overwrites the new correction coefficient until it is updated next time. Is used.

  When the correction coefficient is determined / updated (S206), the used buffer data is cleared (S207), and one routine of this process is terminated.

  Thus, according to the present embodiment, the output value of the vehicle speed sensor, the yaw rate sensor, or the acceleration sensor using the numerical value of the vehicle speed, the yaw rate, or the acceleration calculated using the GPS data obtained by the high-accuracy GPS. Since the sensor is corrected in the sensor, accurate sensor output values can be obtained even if the detection accuracy of the sensor hardware itself is relatively low. In various controls using these sensor output values (for example, There is no need to perform correction processing (using GPS data).

  As will be apparent to those skilled in the art, in the above-described embodiment, the size of the allowable error circle TH1, the length of the maximum allowable buffer time interval TH2, and / or the number of the minimum required number of samples TH3 depends on the sensor type. It may vary from one to the other and / or from one individual sensor to another.

  In the above embodiment, as an example, all the GPS data detected by the position detection unit 101 is passed to the correction coefficient determination unit 105. However, the present invention is not limited to this, for example, S202 in FIG. Or performing a coarser filtering process different from the filtering process on the position detecting unit 101 side, and transmitting only a part of the selected GPS data to the correction coefficient determining unit 105. .

  Moreover, in the said one Example, when the own vehicle carries the navigation system, the position detection part 101 may be combined with the said navigation system. In other words, when the GPS data can be acquired from the navigation system, the vehicle-mounted device 100 itself according to the present invention does not need to include the unique position detection unit 101.

Furthermore, in the above-described embodiment, for the sake of simplicity, the vehicle speed and yaw rate calculated using the GPS data by multiplying the vehicle speed, yaw rate, or acceleration value detected by the detection unit 103 by the correction coefficient. The correction coefficient is determined so as to coincide with the acceleration value, but this is the simplest correction model, and the correction coefficient determination unit 105 is not a simple correction coefficient for more accurate correction. , Correction function f (x):
(Calculated value from GPS data) = f (detected value by the detecting unit 103)
Should be determined.

  In this case, the correction function f (x) may have any number of dimensions and order, and is determined by a fitting operation such as a least square method. Since such an operation is known to those skilled in the art, a detailed description thereof is omitted here. In this embodiment, any method can be used.

  Further, in this case, the correction unit 104 does not simply multiply the detection value by the detection unit 103 by the correction coefficient, but applies the detection value to the correction function f (x).

  The present invention can be used for an in-vehicle device that detects a vehicle behavior state such as a vehicle speed, a yaw rate, or an acceleration. The appearance, weight, size, running performance, etc. of the vehicle to be mounted are not limited. The vehicles here include not only four-wheeled vehicles but also two-wheeled vehicles. In addition, the present invention can be applied to a moving body other than a vehicle such as a ship or an airplane.

It is a schematic block diagram of the vehicle-mounted apparatus which concerns on one Example of this invention. It is a flowchart which shows the flow of the correction coefficient determination / update process by the vehicle-mounted apparatus which concerns on one Example of this invention. It is a figure which shows an example of the log | history of the own vehicle position. It is a figure which shows an example of the point Q which defines each calculation value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 In-vehicle apparatus 101 Position detection part 102 In-vehicle sensor unit 103 Detection part 104 Correction part 105 Correction coefficient determination part

Claims (2)

An in-vehicle device for detecting a vehicle behavior state in a vehicle,
Position detecting means for detecting the current position of the host vehicle;
Calculating means for calculating a first value representing a behavior state of the own vehicle based on a history of the current position of the own vehicle detected by the position detecting means;
Output means for detecting a behavior state of the host vehicle and outputting a second value representing the behavior state;
An in-vehicle apparatus, comprising: a determination unit that determines a correction coefficient for the second value output by the output unit using the first value calculated by the calculation unit. The in-vehicle device according to claim 1,
The in-vehicle device characterized in that the behavior state is a vehicle speed, a yaw rate, or an acceleration.

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