JP2012163509A - Dead reckoning navigation device for vehicle, dead reckoning navigation method for vehicle and program for dead reckoning navigation method for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dead reckoning navigation device for a vehicle capable of improving accuracy of calculating velocity and a yaw rate of a vehicle.SOLUTION: The present invention comprises: a velocity vector calculation means to calculate velocity vector of a traveling velocity of a vehicle from GPS information; a tire rotation information detection means to detect rotation information of a tire; a tire rotation velocity calculation means to calculate rotation velocity of the tire from the rotation information of the tire; a velocity calculation means to calculate velocity of the vehicle based on the information on the velocity vector; a yaw rate calculation means to calculate a yaw rate of the vehicle based on the information on the velocity vector; a first parameter calculation means to sequentially calculate a first parameter for a first relational expression between the velocity of the vehicle calculated by the velocity calculation means and the rotation velocity of the tire; and a second parameter calculation means to sequentially calculate a second parameter for a second relational expression between the yaw rate calculated by the yaw rate calculation means and the rotation velocity of the tire.

Description

  The present invention relates to a vehicle estimated navigation apparatus, a vehicle estimated navigation, and a vehicle estimated navigation program.

  A ground navigation system that provides vehicle travel guidance performs navigation using signals from GPS satellites, but signals from the GPS satellites cannot be received sufficiently due to signal blocking or reflection by high-rise buildings. Then, accurate driving guidance cannot be performed.

  In view of this, conventionally, a device has been devised in which navigation is not interrupted by performing estimated navigation in some way when signals from GPS satellites cannot be sufficiently received. However, many of them use sensor information obtained from a yaw rate sensor or an acceleration sensor, which has been a cause of cost increase.

  For this reason, the present applicant has proposed a vehicle estimated navigation apparatus and a vehicle estimated navigation capable of performing accurate estimated navigation without using an additional sensor (Japanese Patent Application No. 2009-265126. "Invention of the application").

  The vehicle estimated navigation apparatus according to the prior invention uses vehicle rotational speed information, estimates parameters of a mathematical model for calculating the ground speed of the tire from the rotational speed of the tire at the time of GPS reception, When reception is impossible, the vehicle speed and yaw rate are calculated using the parameters.

Specifically, the vehicle estimated navigation apparatus according to the invention of the prior application includes speed vector calculation means for calculating a speed vector of the traveling speed of the vehicle from GPS information by a GPS receiver mounted on the traveling vehicle,
Tire rotation information detecting means for detecting rotation information of a tire mounted on the vehicle;
Tire rotation speed calculation means for calculating the rotation speed of the tire from the rotation information of the tire obtained by the tire rotation information detection means;
Speed calculating means for calculating the speed of the vehicle based on the information of the speed vector;
Yaw rate calculating means for calculating the yaw rate of the vehicle based on the information of the speed vector;
The first relational expression between the vehicle speed calculated by the speed calculation means and the tire rotation speed obtained from a mathematical model for calculating the ground speed of the tire from the tire rotation speed obtained by the tire rotation speed calculation means. First parameter calculating means for calculating one parameter;
The second relational expression of the second relational expression between the yaw rate calculated by the yaw rate calculation means and the tire rotation speed obtained from the mathematical model for calculating the ground speed of the tire from the rotation speed of the tire obtained by the tire rotation speed calculation means. Second parameter calculating means for calculating a parameter.

  At the time of GPS reception, regarding the vehicle speed, the relationship between the speed V obtained from the GPS and the sum x of the rotational speeds of the inner and outer rings is V = A1 × x + B1, and the parameters A1 and B1 are estimated.

  Regarding the yaw rate, the relationship between the yaw rate Y obtained from the GPS, the square z of the sum of the inner and outer ring rotation angular velocities, and the difference y between the inner and outer ring rotation angular velocities is Y = A2 × y / (B2 × z + C2), and the parameter A2 , B2 and C2 are estimated.

  When GPS is not received, the vehicle speed and yaw rate are calculated using the parameters A1, B1, A2, B2, C2, and the rotation speed of the tire, and the estimated navigation is performed using the calculated information.

  As a specific implementation method of the invention of the prior application, (1) at the time of GPS reception, the GPS speed, the GPS yaw rate, and the unit time for sampling (for example, every 1 sec when data sampling is performed every 1 sec) The wheel rotation angular velocity obtained from the ABS signal of the ABS mounted on the vehicle is calculated, and these are substituted into the relational expression described above to estimate the parameters. And (2) When GPS is not received, there is a method of estimating the vehicle speed and the yaw rate by using the wheel rotation angular velocity and the estimated parameter value every 1 sec.

  With such a calculation method, statistically significant parameter estimation is possible when learning travels (travel during GPS reception) at various vehicle speeds. However, the parameters described above are estimated using the least square method or the like. For example, in an extreme traveling mode such as traveling at a constant speed during learning, the parameters cannot be estimated correctly.

  Therefore, if the vehicle travels only at a constant speed during learning and then travels in another speed region when GPS is not received, the parameters may not be optimized. In such a case, since the vehicle speed and yaw rate cannot be estimated correctly, the difference between the actual route and the estimated route is considered to be large.

  The present invention has been made in view of such circumstances, and it is possible to improve the vehicle speed and yaw rate calculation accuracy based on parameters obtained by learning at the time of GPS reception. The purpose is to provide navigation and vehicle estimation navigation programs.

(1) A vehicle estimated navigation apparatus according to the present invention includes speed vector calculation means for calculating a speed vector of a traveling speed of the vehicle from GPS information by a GPS receiver mounted on the traveling vehicle,
Tire rotation information detecting means for detecting rotation information of a tire mounted on the vehicle;
Tire rotation speed calculation means for calculating the rotation speed of the tire from the rotation information of the tire obtained by the tire rotation information detection means;
Speed calculating means for calculating the speed of the vehicle based on the information of the speed vector;
Yaw rate calculating means for calculating the yaw rate of the vehicle based on the information of the speed vector;
The first relational expression between the vehicle speed calculated by the speed calculation means and the tire rotation speed obtained from a mathematical model for calculating the ground speed of the tire from the tire rotation speed obtained by the tire rotation speed calculation means. First parameter calculating means for sequentially calculating one parameter;
The second relational expression of the second relational expression between the yaw rate calculated by the yaw rate calculation means and the tire rotation speed obtained from the mathematical model for calculating the ground speed of the tire from the rotation speed of the tire obtained by the tire rotation speed calculation means. Second parameter calculating means for sequentially calculating parameters, and
The first parameter calculation unit and the second parameter calculation unit are configured to calculate the first parameter and the second parameter, respectively, for each of a plurality of predetermined tire rotation speed regions.

  The vehicle estimated navigation apparatus of the present invention includes:

(2) In the vehicle estimated navigation apparatus according to (1), the first parameter calculation means and the second parameter calculation means always calculate the first parameter and the second parameter when receiving GPS information, respectively, and receive GPS information. When it is impossible, the vehicle speed and the yaw rate can be calculated from the tire rotation speed using the latest parameters of the tire rotation speed region to which the tire rotation speed belongs.

(3) In the vehicle estimated navigation apparatus of (1), the first parameter calculation means and the second parameter calculation means always calculate the first parameter and the second parameter, respectively, when receiving GPS information, and receive GPS information. When the parameters of the tire rotation speed region to which the tire rotation speed belongs at that time are not calculated and the parameters of the other plurality of tire rotation speed regions are calculated, the interpolation or extrapolation of the plurality of parameters is not possible. Thus, it is possible to estimate the parameter of the tire rotation speed region to which the tire rotation speed at that time belongs, and to calculate the vehicle speed and the yaw rate from the tire rotation speed using the estimated parameter.

(4) In the vehicle estimated navigation apparatus of (1), the first parameter calculating means and the second parameter calculating means always calculate the first parameter and the second parameter when receiving GPS information, respectively, and receive GPS information. When the parameter of the tire rotation speed region to which the tire rotation speed at that time belongs is not calculated and the number of other tire rotation speed areas for which the parameter is calculated is 1 or zero, the predetermined default parameter The vehicle speed and the yaw rate can be calculated from the tire rotation speed using.

(5) In the vehicle estimated navigation apparatus of (1) to (4), when the vehicle speed obtained by the speed calculating means is V and the sum of the inner and outer ring rotational angular velocities is x, the first relational expression is , V = A1 × x + B1, where A1 and B1 are the first parameters,
When the yaw rate obtained by the yaw rate calculation means is Y and the difference between the inner and outer ring rotational angular velocities is y, the second relational expression is Y = C × y + D, where C and D are the second parameters. Can do.

(6) In the vehicle estimated navigation apparatus of (1) to (5), it is preferable that the rotational speed is a rotational speed of a driven wheel tire. In this case, the calculation of the rotation speed of the tire is not affected by the slip ratio, so that the rotation speed can be calculated more accurately.

(7) The vehicle estimated navigation according to the present invention includes a speed vector calculating step of calculating a speed vector of a traveling speed of the vehicle from GPS information by a GPS receiver mounted on the traveling vehicle;
A tire rotation speed calculation step for calculating the rotation speed of the tire from the rotation information of the tire obtained by tire rotation information detection means for detecting rotation information of the tire mounted on the vehicle;
A speed calculating step of calculating the speed of the vehicle based on the information of the speed vector;
A yaw rate calculation step of calculating a yaw rate of the vehicle based on the information of the speed vector;
The first relational expression between the vehicle speed calculated in the speed calculation step and the tire rotation speed obtained from a mathematical model for calculating the ground speed of the tire from the tire rotation speed obtained in the tire rotation speed calculation step. A first parameter calculating step of sequentially calculating one parameter;
A second relational expression of the second relational expression between the yaw rate calculated in the yaw rate calculation step and the tire rotation speed obtained from a mathematical model for calculating the ground speed of the tire from the rotation speed of the tire obtained in the tire rotation speed calculation step. A second parameter calculation step of sequentially calculating parameters,
In the first parameter calculating step and the second parameter calculating step, the first parameter and the second parameter are calculated for each of a plurality of predetermined tire rotation speed regions.

(8) In the vehicle estimated navigation of (7), the first parameter calculation step and the second parameter calculation step always calculate the first parameter and the second parameter, respectively, when GPS information is received, and GPS information cannot be received. Sometimes, the vehicle speed and yaw rate can be calculated from the tire rotational speed using the latest parameters of the tire rotational speed region to which the tire rotational speed belongs.

(9) In the vehicle estimated navigation of (7), the first parameter calculation step and the second parameter calculation step always calculate the first parameter and the second parameter when GPS information is received, respectively, and GPS information cannot be received. Sometimes, when the parameter of the tire rotation speed region to which the tire rotation speed belongs at that time is not calculated and the parameters of the other plurality of tire rotation speed regions are calculated, by interpolation or extrapolation of the plurality of parameters The parameters of the tire rotation speed region to which the tire rotation speed belongs at that time can be estimated, and the vehicle speed and the yaw rate can be calculated from the tire rotation speed using the estimated parameters.

(10) In the vehicle estimated navigation of (7), the first parameter calculation step and the second parameter calculation step always calculate the first parameter and the second parameter when GPS information is received, respectively, and GPS information cannot be received. Sometimes, when the parameter of the tire rotation speed region to which the tire rotation speed at that time belongs is not calculated and the number of other tire rotation speed regions for which the parameter is calculated is 1 or zero, a predetermined default parameter is set. The vehicle speed and yaw rate can be calculated from the tire rotation speed.

(11) In the vehicle estimated navigation of (7) to (10), when the vehicle speed obtained by the speed calculating means is V and the sum of the inner and outer ring rotational angular velocities is x, the first relational expression is V = A1 × x + B1, where A1 and B1 are the first parameters,
When the yaw rate obtained by the yaw rate calculation means is Y and the difference between the inner and outer ring rotational angular velocities is y, the second relational expression is Y = C × y + D, where C and D are the second parameters. Can do.

(12) In the vehicle estimated navigation described in (7) to (11), it is preferable that the rotational speed is a rotational speed of a driven wheel tire. In this case, the calculation of the rotation speed of the tire is not affected by the slip ratio, so that the rotation speed can be calculated more accurately.

(13) The vehicle estimated navigation program of the present invention uses a computer to execute the estimated navigation, and calculates a velocity vector of the traveling speed of the vehicle from GPS information by a GPS receiver mounted on the traveling vehicle. Calculating means, tire rotation speed calculating means for calculating the rotation speed of the tire from tire rotation information obtained by tire rotation information detecting means mounted on the vehicle, and calculating the speed of the vehicle based on the information of the speed vector. The speed calculation means, the yaw rate calculation means for calculating the yaw rate of the vehicle based on the information on the speed vector, and the mathematical model for calculating the ground speed of the tire from the tire rotation speed obtained by the tire rotation speed calculation means, The first parameter of the first relational expression between the vehicle speed calculated by the speed calculation means and the tire rotation speed is provided. A first parameter calculating means for sequentially calculating a meter, and a yaw rate calculated by the yaw rate calculating means obtained from a mathematical model for calculating the ground speed of the tire from the rotational speed of the tire obtained by the tire rotational speed calculating means; Function as second parameter calculation means for sequentially calculating the second parameter of the second relational expression with the tire rotation speed,
The first parameter calculation unit and the second parameter calculation unit are configured to calculate the first parameter and the second parameter, respectively, for each of a plurality of predetermined tire rotation speed regions.

(14) In the vehicle estimated navigation program of (13), the first parameter calculation means and the second parameter calculation means always calculate the first parameter and the second parameter, respectively, when GPS information is received. When reception is not possible, the vehicle speed and the yaw rate can be calculated from the tire rotation speed using the latest parameters of the tire rotation speed region to which the tire rotation speed belongs.

(15) In the vehicle estimated navigation program of (13), the first parameter calculation means and the second parameter calculation means always calculate the first parameter and the second parameter, respectively, when GPS information is received. When reception is not possible, if the parameters of the tire rotation speed region to which the current tire rotation speed belongs are not calculated and parameters of other tire rotation speed regions are calculated, interpolation or extrapolation of the plurality of parameters is performed. By inserting, it is possible to estimate the parameter of the tire rotation speed region to which the tire rotation speed belongs, and calculate the vehicle speed and the yaw rate from the tire rotation speed using the estimated parameter.

(16) In the vehicle estimated navigation program of (13), the first parameter calculation means and the second parameter calculation means always calculate the first parameter and the second parameter, respectively, when GPS information is received. When reception is not possible, if the parameter of the tire rotation speed region to which the tire rotation speed at that time belongs is not calculated and the number of other tire rotation speed regions for which the parameter is calculated is 1 or zero, a predetermined default The vehicle speed and the yaw rate can be calculated from the tire rotation speed using parameters.

(17) In the vehicle estimated navigation program of (13) to (16), when the vehicle speed obtained by the speed calculating means is V and the sum of the inner and outer ring rotational angular velocities is x, the first relational expression V = A1 × x + B1, where A1 and B1 are the first parameters,
When the yaw rate obtained by the yaw rate calculation means is Y and the difference between the inner and outer ring rotational angular velocities is y, the second relational expression is Y = C × y + D, where C and D are the second parameters. Can do.

(18) In the vehicle estimated navigation program of (13) to (17), it is preferable that the rotational speed is a rotational speed of a driven wheel tire. In this case, the calculation of the rotation speed of the tire is not affected by the slip ratio, so that the rotation speed can be calculated more accurately.

  According to the vehicle estimated navigation apparatus, the vehicle estimated navigation program, and the vehicle estimated navigation program of the present invention, it is possible to improve the calculation accuracy of the vehicle speed and yaw rate based on the parameters obtained by learning at the time of GPS reception.

It is a block diagram which shows one Embodiment of the estimated navigation apparatus for vehicles of this invention. It is a block diagram which shows the electric constitution of the estimation navigation apparatus for vehicles shown by FIG. It is a flowchart of one embodiment of the vehicle estimated navigation of the present invention. It is a flowchart of one embodiment of the vehicle estimated navigation of the present invention. It is a figure which shows the driving | running route at the time of experiment. It is a figure which shows the relationship between the wheel speed average value on either side, and 1 / C. It is a figure which shows the driving | running route estimated in Example 1 and Comparative Example 1. FIG. It is a figure which shows the driving | running route estimated in Example 2 and Comparative Example 2. FIG.

Hereinafter, embodiments of a vehicle estimated navigation apparatus, a vehicle estimated navigation, and a vehicle estimated navigation program according to the present invention will be described in detail with reference to the accompanying drawings.
As shown in FIG. 1, a vehicle estimated navigation apparatus according to an embodiment of the present invention includes four tires FL (left front wheel), FR (right front wheel) provided in a four-wheel vehicle (front wheel drive vehicle). , RL (left rear wheel) and RR (right rear wheel), the normal wheel speed detecting means provided in relation to the tire to detect rotation information of the RL tire and the RR tire which are driven wheels ( Tire rotation information detecting means) 1 is provided.

  As the wheel speed detection means 1, a wheel speed sensor for generating a rotation pulse using an electromagnetic pickup or the like and measuring the rotation angular speed and the wheel speed from the number of pulses can be used. The output of the wheel speed detecting means 1 is given to a control unit 2 which is a computer such as ABS. A GPS device 3 capable of receiving GPS information is connected to the control unit 2.

  As shown in FIG. 2, the control unit 2 stores an I / O interface 2a necessary for passing signals to and from an external device, a CPU 2b that functions as a center of arithmetic processing, and a control operation program for the CPU 2b. The ROM 2c and the RAM 2d from which data is temporarily written or the written data is read when the CPU 2b performs a control operation. In FIG. 2, 3a is a GPS antenna.

  The wheel speed detection means 1 outputs a pulse signal corresponding to the number of rotations of the tire (hereinafter also referred to as “wheel speed pulse”). Further, the CPU 2b calculates the rotational angular velocity of the tire of the driven wheel every predetermined sampling period ΔT (sec), for example, ΔT = 0.05 seconds, based on the wheel speed pulse output from the wheel speed detecting means 1. .

  The vehicle estimated navigation apparatus according to the present embodiment obtains the speed vector of the traveling speed of the vehicle from the GPS information by the wheel speed detecting means (tire rotation information detecting means) 1 and the GPS receiver 3 mounted on the traveling vehicle. Speed vector calculation means for calculating, tire rotation speed calculation means for calculating the rotation speed of the tire from tire rotation information obtained by the tire rotation information detection means, and calculating the vehicle speed based on the information on the speed vector A speed calculation means that calculates the yaw rate of the vehicle based on the information on the speed vector, and a mathematical model that calculates the ground speed of the tire from the tire rotation speed obtained by the tire rotation speed calculation means. The first parameter of the first relational expression between the vehicle speed calculated by the speed calculation means and the tire rotation speed is also shown. First parameter calculating means for sequentially calculating the data, and a yaw rate calculated by the yaw rate calculating means obtained from a mathematical model for calculating the ground speed of the tire from the tire rotational speed obtained by the tire rotational speed calculating means, The second parameter calculating means is configured to sequentially calculate the second parameter of the second relational expression with the tire rotation speed. The first parameter calculation unit and the second parameter calculation unit are configured to calculate the first parameter and the second parameter, respectively, for each of a plurality of predetermined tire rotation speed regions.

  A vehicle estimated navigation program is installed in the control unit 2, and the control unit 2 includes a speed vector calculation unit, a tire rotation speed calculation unit, a speed calculation unit, a yaw rate calculation unit, and a first parameter calculation unit. And function as second parameter calculation means.

In the vehicle estimated navigation apparatus and the vehicle estimated navigation of the present invention, a velocity vector is used as velocity information by GPS, as in the prior invention.
The angle change due to the inner product, that is, the yaw rate is calculated from the change in the velocity vector by GPS, and the tire model parameters are set so that the yaw rate obtained from this GPS information matches the yaw rate calculated from the tire rotation speed as will be described later. presume.

Further, the tire model parameters are estimated so that the vehicle speed calculated by synthesizing the three-dimensional velocity vector by the GPS and the vehicle speed calculated from the tire rotation speed coincide with each other.
In the drive wheel, since not only the load movement during turning but also the slip ratio affects the tire rotation speed, it is preferable to use a driven wheel for calculation of the tire rotation speed.

  In the present invention, in consideration of these tire characteristics, the ground speed of the tire is expressed by a model using the wheel speed, and the optimum model parameter is calculated for each of the plurality of wheel speed areas while the GPS is received. When the GPS cannot be received, the vehicle speed and the yaw rate are calculated using such model parameters (model parameters calculated for the wheel speed region to which the wheel speed belongs). Thereby, the most important azimuth | direction change by estimated navigation can be calculated | required from wheel speed information accurately.

  Next, a tire model focusing on vehicle speed and yaw rate will be described. However, this method is merely an example of model creation, and the present invention is not limited to such a method.

[Vehicle speed and yaw rate calculation method]
The vehicle speed and yaw rate can be calculated from a three-dimensional velocity vector obtained by GPS. For example, as disclosed in JP-A-2002-22816, the amount of deviation can be obtained from the carrier phase of the satellite.

  As the displacement amount in the three-dimensional direction of the receiver, an east-west displacement amount De, a north-south displacement amount Dn, and a vertical displacement amount Du in the fixed earth coordinate system are calculated. Further, instead of the displacement amount of the reception point in the three-dimensional direction, the component velocity Ve in the east-west direction, the component velocity Vn in the north-south direction in the fixed earth coordinate system, and the vertical component are used as the velocity components in the three-dimensional direction of the reception point. The component velocity Vu in the direction is calculated.

  By combining these three-dimensional velocity vectors, an accurate vehicle speed can be calculated by the following equation (1).

  Further, the yaw rate (Y) is calculated by calculating the angle change at each time as an inner product of the velocity vector Vt obtained by vector synthesis of the component velocity Ve in the east-west direction and the component velocity Vn in the north-south direction at a certain time (t). The per-angle change Hd can be calculated by the following equation (2).

  Then, the yaw rate (Y) can be obtained from this Hd as the azimuth change per unit time.

[Tire model]
The dynamic load radius of each of the four wheels can be calculated from the relationship between the speed information when the vehicle is traveling straight by GPS and the tire rotation speed. The dynamic load radius at that time is defined as a reference dynamic load radius, which is Dr.

The dynamic load radii of the inner and outer wheels of the vehicle change due to the lateral G generated when the vehicle turns, and if the amount of change is ΔDr, the tire ground speed Vin on the inside of the turn and the tire ground speed Vout on the outside of the turn Rotation angular velocity ωin and outer ring rotational angular velocity ωout,
Vin = (Dr + ΔDr) × ωin
Vout = (Dr−ΔDr) × ωout
It can be expressed as.
Here, the vehicle speed (V) can be expressed by the following equation (3).

Regarding the yaw rate (Y),
Tire load sensitivity: Deflection amount of tire when unit load is applied = b
Ratio of front and rear equivalent spring constants of vehicle: Load ratio of driven shaft with respect to entire load movement amount = K
Vehicle mass = m
Vehicle tread width = W
Center of gravity height of vehicle = h
Lateral acceleration = ay
Then, the yaw rate (Y) = (Vout−Vin) / W.

Also,
Vout + Vin = Dr × (ωout + ωin)
Vout−Vin = Dr × (ωout−ωin) −ΔDr × (ωout + ωin)
= Dr × (ωout−ωin) −2 × b × K × (h / W) × m × ay × (ωout + ωin)
ay = (Vout + Vin) × (Vout−Vin) / 2W
Therefore, the yaw rate (Y) can be expressed by the following formula (4).

  From the above, it is possible to construct a model in which the vehicle speed (V) and the yaw rate (Y) are expressed by vehicle and tire parameters using the sum and difference of tire inner and outer wheel angular velocities as variables.

[Parameter estimation method]
Among the parameters of the tire model described above, the parameter related to the speed (V) is expressed by the relationship between the speed (V) obtained from the GPS and the sum (x) of the inner and outer ring rotational angular velocities from Equation (3): V = A1 × x + B1 For example, the parameters (A1, B1) can be estimated by the method of least squares.

The parameter related to the yaw rate (Y) is calculated from the equation (4), the yaw rate value (Y) obtained from GPS, the square of the sum of the inner and outer ring angular velocities (z), and the difference between the inner and outer ring angular velocities (y). The relationship is Y = {A2 / (B2 × z + C2)} × y, and the parameters (A2, B2, C2) can be estimated by, for example, the least square method.
Here, for A2 / (B2 × z + C2) which is a coefficient of y, the numerator denominator is divided by A2, and (B2 / A2) = A2 and (C2 / A2) = B2 are replaced.
Y = {1 / (A2 × z + B2)} × y (5)
It can be expressed as. And if 1 / (A2 × z + B2) = C,
Y = C × y
It becomes.

  Regarding the meaning of equation (5), especially for the yaw rate, the load applied to the outer ring increases as the speed increases even at the same yaw rate, and the load applied to the inner ring decreases, so that the dynamic load radius of the tire decreases for the outer ring and increases for the inner ring. Therefore, it is considered that the wheel speed difference between the inner and outer wheels becomes large.

Moreover, when considering the individual difference between the left and right tires, the following equation (6) may be used.
Y = C × y + D (6)
With respect to D in Equation (6), if the difference between the left and right wheel speeds = 0 when the yaw rate = 0 (straight traveling), D = 0. When it is necessary to consider that there is a difference in the left and right tire diameters due to variations in tire lots, etc., the difference between the tire diameters will cause the wheel speed difference between the left and right to be equal to E even at the same left and right speed (straight running). Because it occurs
D = E × 1 / C
It becomes.

In the present invention, the parameter is estimated for each of a plurality of predetermined wheel speed regions. Here, the wheel speed can be the square of the average value of the wheel speeds of the left and right wheels of the vehicle. Further, as the wheel speed region, for example, the wheel speed can be divided by a width of 100 (rad / s) ² .

  In the vehicle estimated navigation of the present invention, when the GPS cannot be received, the vehicle speed and the yaw rate are estimated based on the wheel speed and the parameter, but the parameter of the wheel speed region to which the wheel speed belongs is not estimated. Is also possible. In such a case, in the present invention, the vehicle speed and the yaw rate are estimated as follows.

(1) First, the parameters of the wheel speed region to which the wheel speed calculated when GPS reception is impossible are not estimated, but when parameters in other wheel speed regions are estimated, a plurality of parameters The parameter at the wheel speed is estimated by interpolation or extrapolation at, and the vehicle speed and yaw rate are estimated from the parameter and the wheel speed.

(2) Next, the parameter of the wheel speed region to which the wheel speed calculated when GPS reception is impossible has not been estimated, and the number of other tire rotation speed regions in which the parameter is calculated is 1 or zero In some cases, the vehicle speed and yaw rate are estimated from the wheel speed using predetermined default parameters. This default parameter can be obtained, for example, by conducting an actual vehicle test combining speed × turning R in advance, and is stored in advance in the ROM 2c of the control unit 2.

[Estimated navigation for vehicles]
Next, an embodiment of the vehicle estimated navigation of the present invention will be described with reference to the flowcharts shown in FIGS. In this embodiment, the parameter is estimated every predetermined time at the time of GPS reception, specifically every second, and when the GPS reception is not possible, the vehicle is based on the latest parameters and the wheel speed data estimated. Calculate speed and yaw rate.

First, in step S1, GPS information is received from the GPS device 3. This GPS information includes the absolute position of the vehicle.
In step S2, a pulse signal corresponding to the number of rotations of the tire is input from the wheel speed detecting means 1. The wheel speed detecting means 1 in the present embodiment generates 48 pulses per tire rotation.

  Next, in step S3, it is determined whether or not the signal from the GPS receiver 3 is sufficiently received. Specifically, it is determined by the DOP value (deterioration coefficient of positioning accuracy) output from the GPS, and when the DOP value is equal to or less than a predetermined value, it is determined that the reception state is not good.

If it is determined in step S3 that the signal received from the GPS receiver 3 is in good condition, in step S4, based on the wheel speed (tire rotational angular velocity) and GPS information every predetermined sampling period ΔT = 1 second. A yaw rate based on the vehicle speed and GPS information is calculated. The wheel speed, vehicle speed, and yaw rate are calculated according to the following equations, respectively.
Wheel speed = (2π / 48) × number of pulses / 1
Vehicle speed = distance traveled / 1
Yaw rate = movement angle / 1
Here, the moving distance and the moving angle can be obtained from the amount of change in the absolute position of the vehicle in one second. The wheel speed is calculated for each of the left wheel and the right wheel of the driven shaft.

  Next, in step S5, the parameters (A1, B1, C, D) of the model formula are estimated sequentially by the least square method for each of a plurality of predetermined wheel speed regions. Then, the estimated parameters are stored in the storage unit of the control unit 2. This parameter estimation is always executed when GPS information is received, and the parameter estimated immediately before is sequentially updated to the latest parameter newly estimated.

On the other hand, if it is determined in step S3 that the reception of GPS information is not good or is impossible, in step S6, the wheel at that time (when the reception status of the GPS information is determined in step S3). It is determined whether or not the parameter in the wheel speed region to which the speed belongs is estimated. If it is determined in step S6 that the parameter in the wheel speed region to which the wheel speed at that time belongs is estimated (Yes), the wheel speed at that time is stored in the storage means of the control unit 2 in step S7. The vehicle speed and yaw rate are calculated by the following formulas every predetermined sampling period ΔT = 1 second using the latest parameters.
Vehicle speed V = A1 × Right and left wheel speed x + B1
Yaw rate Y = C x Left and right wheel speed difference y + D

  Based on the vehicle speed and yaw rate calculated in step S7, the estimated navigation of the vehicle is executed in step S8.

  On the other hand, if it is determined in step S6 that the parameter in the wheel speed region to which the wheel speed at that time belongs has not been estimated (No), are parameters in other wheel speed regions determined in step S9? It is determined whether or not.

  If it is determined in step S9 that the parameters of the other plurality of wheel speed regions have been obtained (Yes), in the subsequent step S10, interpolation or extrapolation is performed with the plurality of parameters (at step S3). The parameter at the wheel speed (when the quality of the GPS information reception state is judged) is estimated.

  In step S11, the vehicle speed and yaw rate are calculated based on the wheel speed at that time and the parameters estimated in step S10. Then, in step S12, the estimated navigation of the vehicle is performed based on the calculated vehicle speed and yaw rate. Executed.

  On the other hand, if it is determined in step S9 that the parameters of the other plurality of wheel speed regions are not obtained (No), that is, if the number of other wheel speed regions for which the parameters are obtained is determined to be 1 or zero, step S13. , The default parameters that are preset as parameters and stored in the ROM 2c of the control unit 1 are employed.

  In step S14, the vehicle speed and yaw rate are calculated based on the default parameters adopted in step S13 and the wheel speed at that time, and in step S15, the vehicle speed is calculated based on the calculated vehicle speed and yaw rate. Estimated navigation is performed.

[Example]
Next, examples of the vehicle estimated navigation of the present invention will be described. However, the present invention is not limited to such examples.
(Example 1, Comparative Example 1)
A tire (195 / 60R15 SP10) manufactured by Sumitomo Rubber Industries, Ltd. was mounted on a 1500 cc FF vehicle and ran on the course shown in FIG. The vehicle was equipped with a VBOX (trade name, GPS Speedometer manufactured by Race Logic, UK).

Learning travel First, the course shown in FIG. 5 was traveled at a constant speed at two speed levels (15 km / h, 40 km / h) in a situation where GPS was able to be received.
In Example 1, the wheel speed region was divided by 100 (rad / sec) ² for the average value of the left and right wheel speeds, and the parameter of the yaw rate was estimated according to Y = C × y + D for each wheel speed region.
On the other hand, in Comparative Example 1 according to the invention of the prior application, the speed parameters A1 and B1 were estimated according to the above-described equation V = A1 × x + B1, and the yaw rate parameter was estimated according to the equation (5).
Y = {1 / (A2 × z + B2)} × y

After estimating the parameters by the estimated navigation learning running, the course shown in FIG. 5 was run again at a constant speed (25 km / h) while the parameter estimation was forcibly stopped on the program.
In Example 1, an average value xave of x (sum of left and right wheel speeds) and parameters C and D were obtained for each wheel speed region. Parameters C and D were estimated by interpolation.

Since C = 1 / (A2 × xave ² + B2), since 1 / C = A2 × xave ² + B2, parameters A2 and B2 can be obtained from the relationship between xave ² and 1 / C shown in FIG. The parameter C at this speed (25 km / h) was inversely estimated using A2 and B2. Further, the yaw rate Y is calculated from the obtained C and the y (difference between left and right wheel speeds) at this time, and the yaw angle calculated from the obtained Y is compared with the yaw angle obtained from the GPS information. I asked for the gap.

On the other hand, in Comparative Example 1, the speed and yaw rate were calculated using the wheel speed and the parameters A1, B1, A2, and B2 described above. Then, the yaw angle calculated from the calculated speed and yaw rate was compared with the yaw angle obtained from the GPS information, and the deviation was obtained.
The results are shown in FIG. The amount of deviation of the yaw angle in Example 1 and Comparative Example 1 was about the same, and the performance level difference between the two was small.

(Example 2, comparative example 2)
Similar to Example 1 and Comparative Example 1, tires (195 / 60R15 SP10) manufactured by Sumitomo Rubber Industries, Ltd. were mounted on a 1500 cc FF vehicle and traveled on the course shown in FIG. The vehicle was equipped with a VBOX (trade name, GPS Speedometer manufactured by Race Logic, UK).

Learning Travel A learning travel was performed in the same manner as in Example 1 and Comparative Example 1 except that a constant speed travel was performed on the course shown in FIG. 5 at one speed level (40 km / h), and parameters were estimated.

After estimating the parameters by the estimated navigation learning running, the course shown in FIG. 5 was run again at a constant speed (25 km / h) while the parameter estimation was forcibly stopped on the program.
In the second embodiment, since the parameter of the wheel speed region to which the wheel speed at the time of the estimated navigation belongs is not estimated, and the number of other wheel speed regions in which the parameter is estimated is 1, the default parameter is used as the coefficient C. It was used. On the other hand, for the constant term D, a value obtained during learning running at a speed of 40 km / h was used. The yaw rate Y is calculated from the default parameter C and y (the difference between the left and right wheel speeds) at this time, and the yaw angle calculated from the obtained Y is compared with the yaw angle obtained from the GPS information. Asked.

On the other hand, in Comparative Example 2, the yaw rate was calculated in the same manner as Comparative Example 1. Then, the yaw angle calculated from the calculated yaw rate was compared with the yaw angle obtained from the GPS information, and the deviation was obtained.
The results are shown in FIG. The amount of deviation of the yaw angle in Example 2 is smaller than the amount of deviation of the yaw angle in Comparative Example 2, indicating that the performance of the estimated navigation of the present invention is good.

1 Wheel speed detection means (tire rotation information detection means)
2 Control unit 2a Interface 2b CPU
2c ROM
2d RAM
3 GPS device 3a GPS antenna

Claims (18)

Speed vector calculating means for calculating a speed vector of a traveling speed of the vehicle from GPS information by a GPS receiver mounted on the traveling vehicle;
Tire rotation information detecting means for detecting rotation information of a tire mounted on the vehicle;
Tire rotation speed calculation means for calculating the rotation speed of the tire from the rotation information of the tire obtained by the tire rotation information detection means;
Speed calculating means for calculating the speed of the vehicle based on the information of the speed vector;
Yaw rate calculating means for calculating the yaw rate of the vehicle based on the information of the speed vector;
The first relational expression between the vehicle speed calculated by the speed calculation means and the tire rotation speed obtained from a mathematical model for calculating the ground speed of the tire from the tire rotation speed obtained by the tire rotation speed calculation means. First parameter calculating means for sequentially calculating one parameter;
The second relational expression of the second relational expression between the yaw rate calculated by the yaw rate calculation means and the tire rotation speed obtained from the mathematical model for calculating the ground speed of the tire from the rotation speed of the tire obtained by the tire rotation speed calculation means. Second parameter calculating means for sequentially calculating parameters, and
The first parameter calculation unit and the second parameter calculation unit are configured to calculate the first parameter and the second parameter, respectively, for each of a plurality of predetermined tire rotation speed regions. Estimated navigation device.   The first parameter calculation means and the second parameter calculation means always calculate the first parameter and the second parameter when GPS information is received, respectively, and when GPS information cannot be received, the tire rotation speed region to which the current tire rotation speed belongs belongs. The vehicle estimated navigation apparatus according to claim 1, wherein the vehicle speed and the yaw rate are calculated from the tire rotation speed using the latest parameters.   The first parameter calculation means and the second parameter calculation means always calculate the first parameter and the second parameter when GPS information is received, respectively, and when GPS information cannot be received, the tire rotation speed region to which the current tire rotation speed belongs belongs. When the parameter is not calculated and the parameters of the other plurality of tire rotation speed regions are calculated, the parameters of the tire rotation speed region to which the current tire rotation speed belongs are obtained by interpolation or extrapolation of the plurality of parameters. The vehicle estimated navigation apparatus according to claim 1, wherein the vehicle speed and the yaw rate are calculated from the tire rotation speed using the estimated parameters.   The first parameter calculation means and the second parameter calculation means always calculate the first parameter and the second parameter when GPS information is received, respectively, and when GPS information cannot be received, the tire rotation speed region to which the current tire rotation speed belongs belongs. When the parameter is not calculated and the number of other tire rotation speed regions for which the parameter is calculated is 1 or zero, the vehicle speed and the yaw rate are calculated from the tire rotation speed using a predetermined default parameter. The estimated navigation device for a vehicle according to claim 1 configured as described above. When the vehicle speed obtained by the speed calculation means is V and the sum of the inner and outer ring rotational angular velocities is x, the first relational expression is V = A1 × x + B1, where A1 and B1 are the first parameters. Yes,
When the yaw rate obtained by the yaw rate calculation means is Y and the difference between the inner and outer ring rotational angular velocities is y, the second relational expression is Y = C × y + D, where C and D are the second parameters. The estimated navigation apparatus for vehicles in any one of Claims 1-4.   The estimated navigation device for a vehicle according to any one of claims 1 to 5, wherein the rotation speed is a rotation speed of a driven wheel tire. A speed vector calculating step of calculating a speed vector of the traveling speed of the vehicle from GPS information by a GPS receiver mounted on the traveling vehicle;
A tire rotation speed calculation step for calculating the rotation speed of the tire from the rotation information of the tire obtained by tire rotation information detection means for detecting rotation information of the tire mounted on the vehicle;
A speed calculating step of calculating the speed of the vehicle based on the information of the speed vector;
A yaw rate calculation step of calculating a yaw rate of the vehicle based on the information of the speed vector;
The first relational expression between the vehicle speed calculated in the speed calculation step and the tire rotation speed obtained from a mathematical model for calculating the ground speed of the tire from the tire rotation speed obtained in the tire rotation speed calculation step. A first parameter calculating step of sequentially calculating one parameter;
A second relational expression of the second relational expression between the yaw rate calculated in the yaw rate calculation step and the tire rotation speed obtained from a mathematical model for calculating the ground speed of the tire from the rotation speed of the tire obtained in the tire rotation speed calculation step. A second parameter calculation step of sequentially calculating parameters,
The vehicle estimated navigation characterized in that the first parameter calculation step and the second parameter calculation step calculate the first parameter and the second parameter for each of a plurality of predetermined tire rotation speed regions.   In the first parameter calculation step and the second parameter calculation step, the first parameter and the second parameter are always calculated when GPS information is received. When GPS information cannot be received, the tire rotation speed region to which the tire rotation speed belongs belongs. 8. The vehicle estimated navigation according to claim 7, wherein the vehicle speed and the yaw rate are calculated from the tire rotational speed using the latest parameters.   In the first parameter calculation step and the second parameter calculation step, the first parameter and the second parameter are always calculated when GPS information is received. When GPS information cannot be received, the tire rotation speed region to which the tire rotation speed belongs belongs. When the parameter is not calculated and the parameters of the other plurality of tire rotation speed regions are calculated, the parameters of the tire rotation speed region to which the current tire rotation speed belongs are obtained by interpolation or extrapolation of the plurality of parameters. The vehicle estimated navigation according to claim 7, wherein the vehicle speed and the yaw rate are calculated from the tire rotation speed using the estimated parameters.   In the first parameter calculation step and the second parameter calculation step, the first parameter and the second parameter are always calculated when GPS information is received. When GPS information cannot be received, the tire rotation speed region to which the tire rotation speed belongs belongs. When the parameter is not calculated and the number of other tire rotation speed regions for which the parameter is calculated is 1 or zero, the vehicle speed and the yaw rate are calculated from the tire rotation speed using a predetermined default parameter. The vehicle estimated navigation according to claim 7. When the vehicle speed obtained in the speed calculation step is V and the sum of the inner and outer ring rotational angular velocities is x, the first relational expression is V = A1 × x + B1, where A1 and B1 are the first parameters. Yes,
When the yaw rate obtained in the yaw rate calculation step is Y and the difference between the inner and outer ring rotational angular velocities is y, the second relational expression is Y = C × y + D, where C and D are the second parameters. The vehicle estimated navigation according to any one of claims 7 to 10.   The vehicle estimated navigation according to any one of claims 7 to 11, wherein the rotational speed is a rotational speed of a driven wheel tire. A speed vector calculating means for calculating a speed vector of a running speed of the vehicle from GPS information by a GPS receiver mounted on the running vehicle, and a tire rotation information detecting means mounted on the vehicle for executing the estimated navigation Tire rotation speed calculation means for calculating the rotation speed of the tire from the rotation information of the tire obtained by the above, speed calculation means for calculating the speed of the vehicle based on the information on the speed vector, and on the vehicle based on the information on the speed vector A yaw rate calculation means for calculating a yaw rate, a vehicle speed calculated by the speed calculation means and the tire rotation speed obtained from a mathematical model for calculating the ground speed of the tire from the rotation speed of the tire obtained by the tire rotation speed calculation means First parameter calculating means for sequentially calculating the first parameter of the first relational expression with And a second relational expression of the second relational expression between the yaw rate calculated by the yaw rate calculation means and the tire rotation speed, obtained from a mathematical model for calculating the ground speed of the tire from the rotation speed of the tire obtained by the tire rotation speed calculation means. Function as second parameter calculation means for sequentially calculating two parameters,
The first parameter calculation unit and the second parameter calculation unit are configured to calculate the first parameter and the second parameter, respectively, for each of a plurality of predetermined tire rotation speed regions. Estimated navigation program.   The first parameter calculation means and the second parameter calculation means always calculate the first parameter and the second parameter when GPS information is received, respectively, and when GPS information cannot be received, the tire rotation speed region to which the current tire rotation speed belongs belongs. 14. The vehicle estimated navigation program according to claim 13, wherein the vehicle speed and yaw rate are calculated from the tire rotation speed using the latest parameters.   The first parameter calculation means and the second parameter calculation means always calculate the first parameter and the second parameter when GPS information is received, respectively, and when GPS information cannot be received, the tire rotation speed region to which the current tire rotation speed belongs belongs. When the parameter is not calculated and the parameters of the other plurality of tire rotation speed regions are calculated, the parameters of the tire rotation speed region to which the current tire rotation speed belongs are obtained by interpolation or extrapolation of the plurality of parameters. 14. The vehicle estimated navigation program according to claim 13, wherein the vehicle speed and the yaw rate are calculated from the tire rotation speed using the estimated parameters.   The first parameter calculation means and the second parameter calculation means always calculate the first parameter and the second parameter when GPS information is received, respectively, and when GPS information cannot be received, the tire rotation speed region to which the current tire rotation speed belongs belongs. When the parameter is not calculated and the number of other tire rotation speed regions for which the parameter is calculated is 1 or zero, the vehicle speed and the yaw rate are calculated from the tire rotation speed using a predetermined default parameter. The vehicle estimated navigation program according to claim 13 configured as described above. When the vehicle speed obtained by the speed calculation means is V and the sum of the inner and outer ring rotational angular velocities is x, the first relational expression is V = A1 × x + B1, where A1 and B1 are the first parameters. Yes,
When the yaw rate obtained by the yaw rate calculation means is Y and the difference between the inner and outer ring rotational angular velocities is y, the second relational expression is Y = C × y + D, where C and D are the second parameters. The vehicle estimated navigation program according to any one of claims 13 to 16.   The vehicle estimated navigation program according to any one of claims 13 to 17, wherein the rotational speed is a rotational speed of a driven wheel tire.

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