JPH069303Y2 - Vehicle position detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention relates to a vehicle position detecting device which is improved in direction detection when a shift position is neutral.

<< Prior Art >> Conventionally, as this type of apparatus, the one described in JP-A-61-260116 is known.

In this example, when detecting the current position while the vehicle is traveling, the calculation of the traveling azimuth during traveling for a certain time required is:
First, the difference in track length between the left and right wheels on the front wheels or the rear wheels is detected in a minute time, and then this detected value is divided by the width of the left and right wheels, that is, the tread, to obtain the direction change amount during a minute time. Is further integrated and added to obtain the direction change amount during traveling for a certain time.

The conventional example will be described with reference to FIG. 12. The calculation of the heading change amount Δθ when the vehicle 20 moves from the point A to the point B is as follows.

That is, the left and right wheel speed sensors S _R provided on the rear wheels,
The traveling distance per pulse of S _L is 1, the number of pulses output from the right wheel speed sensor S _R when the vehicle 20 moves from the point A to the point B is P _R , and the pulse output from the left wheel speed sensor S _L When the number is P _L , the vehicle tread is T, and the vehicle turning radius is r, the following equation is first obtained by calculating the track lengths of both wheels.

_{P L · l = Δθ (r} + T) (1) P R · l = Δ · r (2) where (1) - When calculating the (2) the following equation is obtained.

(P _L −P _R ) l = Δθ · T (3) Therefore, the direction change amount Δθ when the vehicle 20 moves from the point A to the point B is Will be required as.

<Problems to be solved by the device> However, in the conventional device as described above, since the difference between the track lengths of the left and right wheels is simply calculated and the azimuth change amount is calculated based on the difference, In this case, there is a problem in that an error that is twice as large as the actual direction change amount occurs.

This will now be described with reference to FIG. 13. For example, in the case where the vehicle 20 is turned back while moving backward in a parking lot or the like, the vehicle 20 moves backward from the point C to the point D in the reverse range and also moves to the point D. Then, it is assumed that the gear shift position is changed to the neutral range, and then the steering wheel goes backward from the point D to the point E while turning the steering wheel to the left and stops at the point E.

In this case, the direction change amount from point D to point E is approximately 90 °
Although the vehicle is moving backward while changing the traveling azimuth, when comparing the movement amounts of the left and right wheels of the vehicle 20, the movement amount of the right wheel is larger in FIG.

Further, in this example, when the shift position is neutral, it is determined that the vehicle is moving forward regardless of whether the vehicle is actually moving forward or backward.

Therefore, when the direction change amount of the vehicle is calculated only from the difference between the locus lengths of the left and right wheels, it is possible to move forward from point D while moving forward.
° It means that the vehicle turned left and the actual vehicle current position is point E, but the calculated vehicle current position is point F, and the actual heading P and the calculated heading Q
And produces an error of 180 °.

<Purpose of Invention> In consideration of the above problems, the present invention, even if the gear shift reverse position coasts in the neutral range,
It is an object of the present invention to provide a vehicle position detection device capable of detecting an actual traveling azimuth and calculating a current position with high accuracy.

<< Means for Solving Problems >> In order to solve the above problems, the present invention is configured as shown in FIG.

In the figure, the traveling distance detecting means a detects the traveling distance of the vehicle.

The traveling azimuth detecting means b detects the traveling azimuth of the vehicle.

The gear shift position detecting means c detects the gear shift position of the vehicle.

Then, the forward / reverse discriminating means d discriminates the forward / reverse movement of the vehicle on the basis of the detected shift shift position, and when the shift shift position is in the neutral range, it is based on the previous shift shift position. The forward / backward movement of the vehicle is determined.

<< Description of Embodiments >> Hereinafter, embodiments of a vehicle position detecting device according to the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram showing the basic configuration of the first embodiment device of the present invention, in which the right rear wheel wheel speed sensor 1 and the left rear wheel wheel speed sensor 2 have a constant value for each rotation of each wheel. Several pulses have been emitted.

A pulse counter 3 counts the number of pulses generated by the wheel speed sensors 1 and 2.

Reference numeral 4 denotes a position calculation computer that calculates the current position of the vehicle based on the counter signal from the pulse counter 3 and the select position signal from the shift selector 6.

Reference numeral 7 is a CRT for displaying the current position of the vehicle calculated by the position calculation computer 4 on the display screen.

Reference numeral 5 is a geomagnetic sensor for detecting the traveling direction of the vehicle.

The apparatus of this embodiment has the above-mentioned configuration, and the processing procedure thereof will be described below with reference to the flowchart.

FIG. 3 is a general flow showing the processing procedure of the apparatus of this embodiment. When the program is started, the initial processing is first performed (step 110).

As a result, first, the vehicle traveling azimuth θ when the system was turned off last time is read from the backup memory built in the position calculation computer 4 into the main memory also built in the position calculation computer 4.

Then, when the interruption permitting processing for the integral settlement interruption processing (step 150) is performed (step 12)
0), we will enter the main loop.

In this main loop, the integral calculation interrupt process (step 1
Each time step 50) is performed, it is determined whether or not the vehicle has moved (step 130), and when the movement of the vehicle is confirmed (YES in step 130), update processing for those movements is performed (step 140).

Next, the integral calculation interrupt process of step 150 will be described with reference to the flowchart of FIG.

This process is carried out every fixed time Δt. First, Δt
The output signals of the right rear wheel wheel speed sensor 1 and the left rear wheel wheel speed sensor 2 during the period are recorded in the pulse counter 3, and the respective pulse numbers are set as the right wheel pulse counter P _R and the left wheel pulse counter P _L. It is stored (steps 210 and 220).

Then, in order to calculate the vehicle travel distance between Δt, the average of both pulse counters P _R and P _L is calculated (step 23).
0).

As described above, when the average number of pulses of the left and right wheels is obtained during the fixed time Δt, next, the forward / backward movement of the vehicle, which is a characteristic part of the apparatus of this embodiment, is determined (step 240). .

Then, in this embodiment apparatus, when it is determined that the vehicle has moved backward during Δt (YES in step 240), 180 ° is added to the traveling direction θ obtained by the geomagnetic sensor 5 based on the forward movement state of the vehicle. The azimuth is obtained as the true vehicle advancing azimuth θ in reverse (step 25).
0).

This is generally 180 in the heading when moving forward and backward.
This is because, since there is a difference of °, the azimuth obtained by adding 180 ° to the azimuth detected by the geomagnetic sensor 5 obtained based on the forward traveling state is adopted as the traveling azimuth when the vehicle is moving backward.

On the other hand, in the forward / reverse determination in step 240, when it is determined that the vehicle has moved forward for Δt (N in step 240).
O), the azimuth detected by the geomagnetic sensor 5 is directly adopted as the vehicle traveling azimuth θ.
The calculation processing of the current position of 60 will be performed.

First, the vehicle movement amounts X ₀ , Y ₀ in the X and Y directions between Δt.
Is expressed by the following equation, where l is the distance traveled by the wheel per pulse.

X ₀ = × l × cos θ (5) Y ₀ = × l × sin θ (6) Therefore, when the current position coordinates are X and Y, the above X ₀ and Y ₀ are added as the X-direction integrated distance and the Y-direction integrated distance. Then, the integration process is updated as shown in the following equation (step 260).

X = X + × 1 × cos θ (7) Y = Y + × 1 × sin θ (8) Finally, the pulse counter 3 is cleared to prepare for the next time, and the integral calculation interrupt process between Δt is completed (step 270).

Next, the processing procedure for determining whether the vehicle is moving forward or backward in step 240 will be described in detail with reference to the flowchart of FIG.

In this process, forward / backward movement is determined by detecting the shift position based on the select position signal from the shift selector 6, and it is first checked whether or not the vehicle is in the reverse range (step 310).

If the shift position is in the reverse range (YES in step 310), The vehicle is judged to be moving backward.

On the other hand, when the shift position detected by the shift selector 6 is not in the reverse range (step 310).
NO), (Step 330).

And If any of the ranges is set (YE in step 310)
S), Is cleared and it is determined that the vehicle is moving forward (step 340).

On the other hand, the shift position detected by the shift selector 6 is If it is not in any of the ranges (N in step 330)
O), and then it is checked whether it is in the neutral range (step 350).

By the way, even when the shift position is in the neutral range, it may be forward or backward by inertia.For example, if the shift position is changed from the reverse range to the neutral range, the inertia is maintained even if it is in the neutral range. It is possible that you are moving backwards.

Therefore, if the shift position is in the neutral range (YES in step 350), Detects the state of (step 360), Is standing (YES at step 360), it is determined that the vehicle is in reverse.

on the other hand, If is cleared (NO in step 360), it is determined that the vehicle is moving forward.

That is, when it is determined that the shift shift position is in the neutral range, the current forward / reverse traveling state is determined by checking the shift shift position before that.

When it is determined in step 350 that the shift position is not in the neutral range (step 350
NO), and it is further checked whether the shift position is in the parking range (step 370).

If it is in the parking range (YES in step 370), it is determined that the vehicle is moving forward, and if not, error processing is performed.

When the vehicle in the parking range or the neutral range is stopped, the current position is not updated, so there is no problem in determining whether the vehicle is moving forward or backward.

As described above, the device of the present embodiment determines whether the vehicle is in the forward drive state or the reverse drive state according to the shift shift position, and when the shift shift position is in the neutral range, the vehicle is currently in the forward drive state or the reverse drive state from the previous shift shift position. To determine if it is.

Therefore, coasting in the case of the neutral range can be reliably detected, and the current vehicle position can be accurately detected.

Next, a second embodiment device of the present invention will be described with reference to FIGS.

FIG. 6 is a block diagram showing the basic configuration of the device of the second embodiment, in which the right rear wheel wheel speed sensor 1 is provided integrally with a wheel (not shown) inside the central portion of the right rear wheel. It is composed of a gear 11 and a large gear pickup 11a for detecting the teeth 11b of the large gear, and outputs a constant pulse per one rotation of the tire.

Further, the left rear wheel wheel speed sensor 2A includes a large gear 11 provided integrally with the wheel 10 inside the central portion of the left rear wheel 10, and a small gear 1 further overlapped on the large gear 11.
2, a large gear pickup 11a for detecting the teeth 11b, 12b of the both gears 11, 12 and a small gear pickup 12a (see FIGS. 7 (a), (b) and (c)).

Here, the large gear 11 and the small gear 12 have the same number of teeth and both teeth are assembled with a constant phase difference. Now, when the pitch of both gears is α degrees,
Both teeth 11b, 1 with a phase difference of less than 1/2 α degree
2b is detected by each of the pickups 11a and 12a (see FIG. 8).

Reference numeral 3 is a pulse counter for counting the number of pulses generated from the right rear wheel wheel speed sensor 1 and the left rear wheel wheel speed sensor 2A.

Reference numeral 8 denotes a forward / backward movement determination unit that determines forward / backward movement of the vehicle based on detection signals from two pickups 11a and 12a provided on the left rear wheel speed sensor 2A.

In the figure, the position calculation computer 4, the geomagnetic sensor 5 and the CRT 7 are the same as those in the first embodiment, and therefore detailed description thereof will be omitted.

The second embodiment device is constructed as described above,
Next, the processing procedure will be described.

By the way, the only difference between the processing procedure of this embodiment and the processing procedure of the apparatus of the first embodiment is the method for determining forward / backward movement in step 240.

Therefore, the forward / backward traveling determination method in the apparatus of this embodiment will be described below with reference to FIGS. 6 to 8.

That is, when discriminating between forward and backward movements in this embodiment, the output of the forward and backward movement determination unit 8 (for example, HIGH when the vehicle is moving forward, LOW when the vehicle is moving backward).
Is detected, the forward / backward movement is determined.

Hereinafter, the operation of the forward / backward traveling determination unit 8 will be described.

A pulse signal obtained when the teeth 11b and 12b of the large gear 11 and the small gear 12 provided on the left rear wheel speed sensor 2A are detected by the large gear pickup 11a and the small gear pickup 12a is shown in FIG. As shown in (a) and (b).

This is determined in advance by the phase difference when assembling the two gears 11 and 12.

Further, in this example, the phase difference t between the two gears 11 and 12 is t.
Let α be the pitch of both gears 11 and 12, Is configured.

Therefore, the time t ₁ from the pulse signal of the large gear 11 to the pulse signal of the small gear 12 and the small gear 12
When the time t ₂ from the pulse signal of 1 to the pulse signal of the large gear 11 is compared, if t ₁ <t ₂ (10), it can be determined that the vehicle is moving forward.

On the other hand, if t ₁ > t ₂ (11), it can be determined that the vehicle is in reverse.

This determination is uniquely determined by the preset phase difference between the large gear 11 and the small gear 12.

As described above, this second embodiment device is provided with two large and small gears having the same pitch integrally with the wheel, and the mounting positions of both gears are shifted so that pulses of both gears are generated with a predetermined phase difference. Has been done.

Therefore, by comparing the pulses of the two gears, the forward / backward traveling state of the vehicle can be accurately determined with a simple device.

Next, a third embodiment of the present invention will be described with reference to FIGS. 9 and 10.

FIG. 9 is a block diagram showing the basic configuration of the apparatus of this embodiment, but the difference from the apparatus of the first embodiment is that the apparatus of this embodiment is not provided with the geomagnetic sensor 5.

The third embodiment is characterized in that the right rear wheel wheel speed sensor 1 and the left rear wheel wheel speed sensor 2 detect the traveling azimuth of the vehicle used in the calculation processing in the position calculation computer 4. What is done by calculating the wheel speed difference and the forward / backward traveling state of the vehicle are discriminated, and when it is discriminated that the vehicle is moving backward, the sign of the direction change amount detected assuming the traveling state is changed and That is, the amount of azimuth change is calculated.

Therefore, the only difference from the processing procedure of the apparatus of the first embodiment is the integral calculation interrupt processing in step 150.

Therefore, the integral calculation interrupt process of the device of the third embodiment will be described with reference to the flowchart of FIG.

This process is carried out every fixed time Δt. First, Δt
Between, the output signal of the right rear wheel speed sensors 1 and the left rear wheel speed sensor 2 is recorded in the pulse counter 3, each pulse number is right wheel pulse counter P _R
And left wheel pulse counter P _L (steps 410 and 420).

In this way, when the pulse counters of the left and right wheels that are traveling for a certain period of time Δt are stored, the difference ΔP between the pulse counters of the left and right wheels and the average value of the pulse counters are calculated by the following equation (step 430).

ΔP = P _R −P _L (12) Here, the difference ΔP between the two pulse counters is obtained in order to obtain the change amount Δθ of the vehicle traveling direction after the elapse of the fixed time Δt.

Also, the average value of the pulse counter of both wheels is calculated by
This is because the traveling distance of the vehicle that has traveled between Δt is obtained.

Then, the tread that is the distance between the left and right wheels of the vehicle is T,
Assuming that the distance traveled by the wheel per pulse is 1, the direction change amount Δθ between Δt is given by the following equation (step 44).
0).

As described above, the average pulse counter and the amount of heading change Δ which serve as reference data for detecting the current position of the vehicle.
When θ is obtained, the forward / backward movement of the vehicle is next determined prior to the detection of the current vehicle position (step 45).
0).

This is done by detecting the shift position in response to the select position signal from the shift selector 6, but since the processing procedure of step 450 is exactly the same as that of step 240, its detailed description is omitted.

If it is determined in step 450 that the vehicle is moving backward (YES in step 450), -Δθ is set as the amount of change in the traveling direction Δθ during the backward movement (step 460) and added to the current traveling direction θ of the vehicle (step 470). ).

This is because when the amount of heading change Δθ is detected assuming that the vehicle is moving forward, if the vehicle is in reverse, there is actually a heading change of −Δθ. This is to correct the error of.

On the other hand, if it is determined in step 450 that the vehicle is moving forward (NO in step 450), the calculated heading change amount Δθ is added to the current heading θ as it is.

On the other hand, the vehicle movement amounts X ₀ , Y in the X and Y directions between Δt.
₀ can be expressed by the following equation.

X ₀ = × l × cos θ (15) Y ₀ = × l × sin θ (16) Therefore, when the current position coordinates are X and Y, the above X ₀ and Y ₀ are added as the X-direction integrated distance and the Y-direction integrated distance. And is updated by the integration processing (step 480).

Then, finally, the pulse counter 3 is cleared, and the integral calculation interrupt process for the fixed time Δt is completed in preparation for the next time (step 490).

As described above, the device of the third embodiment obtains the heading change amount and the heading of the vehicle based on the wheel speed difference between the two wheels.

Then, the forward / backward traveling state of the vehicle is determined, and when it is determined that the vehicle is traveling backward, the sign of the azimuth variation that is detected assuming that the vehicle is traveling is changed to obtain the azimuth variation when traveling backward.

Therefore, the correction of the traveling direction of the vehicle is always performed accurately even when the vehicle is moving backward, and the current vehicle position is accurately detected.

Next, FIG. 11 is a block diagram showing the basic construction of the fourth embodiment of the device of the present invention.

The device of the fourth embodiment differs from the device of the second embodiment in that the device of this embodiment is not provided with the geomagnetic sensor 5.

In the fourth embodiment, the vehicle traveling direction is detected by the wheel speed difference between the right rear wheel wheel speed sensor 1 and the left rear wheel wheel speed sensor 2A, as in the third embodiment. Therefore, detailed description thereof will be omitted.

<Effect of the Invention> As described above, the vehicle position detecting device according to the present invention determines whether the vehicle is moving forward or backward based on the gear shift position, and when the gear shift position is in the neutral range, the gear shift before that is performed. By checking the shift position, the forward / backward traveling state of the vehicle is determined.

Therefore, even if the gear shift reverse position is in the neutral range and the vehicle reverses backward, the actual traveling direction can be detected, and the present position can be calculated accurately.

[Brief description of drawings]

1 is a block diagram showing the claims of the present invention, FIG. 2 is a block diagram showing the system configuration of the first embodiment of the present invention, and FIG.
The figure shows the general flow of the apparatus of the first embodiment, and FIG. 4 shows the first.
5 is a flow chart showing an integral calculation interruption process in the embodiment apparatus, FIG. 5 is a flow chart showing a forward / backward movement discriminating method of the first embodiment apparatus, and FIG. 6 is a basic configuration of the second embodiment apparatus of the present invention. FIG. 7 is a block diagram showing the wheel speed sensor of the second embodiment device, FIG. 8 is an explanatory view of forward / backward traveling discrimination operation in the second embodiment device, and FIG. 9 is a third embodiment of the present invention.
10 is a block diagram showing the basic configuration of the apparatus of the present invention, FIG. 10 is a flow chart showing the integral calculation interrupt processing in the apparatus of the third embodiment, and FIG. 11 is the basic configuration of the apparatus of the fourth embodiment of the present invention. Block diagrams, FIGS. 12 and 13 are explanatory views of a vehicle position detecting device in a conventional example. 1 ... right rear wheel wheel speed sensor 2, 2A ... left rear wheel wheel speed sensor 3 ... pulse counter 4 ... position calculation computer 5 ... geomagnetic sensor 6 ... shift selector 7 ... CRT 8 ... forward / reverse discriminating unit

Claims (1)

[Scope of utility model registration request] 1. A vehicle having: a traveling distance detecting means for detecting a traveling distance of the vehicle; a traveling direction detecting means for detecting a traveling direction of the vehicle; and a shift shift position detecting means for detecting a shift position of the vehicle. In the position detection device, the forward / backward movement of the vehicle is determined based on the detected shift shift position, and when the shift shift position is in the neutral range, the vehicle forward / backward movement is performed based on the previous shift shift position. A vehicle position detecting device having a forward / backward movement judging means for judging.