JPH0346761B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the position and attitude angle at a calibration point for recording the travel trajectory of a motor vehicle.

Records of vehicle travel trajectories have important implications not only for research into the operation of autonomous vehicles and intelligent vehicles, but also for vehicle operation management systems.

When such a driving trajectory is recorded based on measurements such as the number of revolutions of the rear wheels of a car, errors gradually accumulate, and the recording device ends up drawing a trajectory that deviates significantly from the route actually traveled by the car. Therefore, in order to prevent the accumulation of errors, calibration points are set up at appropriate intervals on the driving surface, and information regarding the position and attitude angle of the vehicle when passing through the calibration points is sent to a recording device to correct the trajectory. It is necessary to take corrective measures such as

The present invention aims to provide a method for easily measuring the position of the vehicle at such a calibration point, that is, the absolute coordinates (x, y) and the attitude angle of the vehicle, on the vehicle. A mark having a pair of mutually parallel straight line portions oriented in a direction approximately perpendicular to the expected direction of travel of the vehicle, and a mark having a pair of mutually parallel straight line portions not parallel to the straight line portions are attached to the mark. As a detection means for the mark, one lamp that illuminates the road surface and one light receiving element that receives reflected light from the road surface are provided on the vehicle, and this detection means detects between the parallel straight parts of the mark and This method is characterized by measuring the time required to pass between non-parallel straight line sections, and measuring the passing position and attitude angle of the vehicle at a calibration point based on this time, vehicle speed, and mark size.

The present invention will be explained in more detail below with reference to the drawings.

First, calibration points are installed at appropriate intervals on the surface where the car is running, and at these calibration points, as illustrated in FIG. Attach calibration point mark 3.

The calibration point mark 3 consists of a rectangular mark 4 having a long constant width in a direction substantially perpendicular to the direction in which the car is expected to travel at a calibration point on the running surface, and a rectangular mark 4 arranged parallel to the rectangular mark 4. The mark is composed of a trapezoidal mark 5 whose width is not constant because the front and rear edges of the mark are in a linear shape that is not parallel to each other, and a parallelogram mark 6 which is set parallel to the inclined sides of the trapezoidal mark.

On the other hand, as shown in FIG.
A lamp 11 arranged to illuminate the road surface 1 and a light-receiving element 12 that receives reflected light from the lamp from above the road surface 1 are partitioned by a partition wall 13 at the bottom of the screen. It will be arranged as follows. This arrangement position is preferably near the center of the rear wheel, for example.

A car with such a configuration sets the calibration point to the first point.
Assuming that it passes in the direction of angle θ shown by arrow A in the figure, from the light receiving element 12, as shown in FIG. 3,
The light reception level output for t ₁ hour is based on the reflected light from the rectangular mark 4, the light reception level output for t ₂ hours is based on the reflected light from the trapezoidal mark 5, and the light reception level output for t ₃ hours is based on the reflected light from the parallelogram mark 6. A signal consisting of a received light level output is output. car is an arrow
A similar signal is output when passing in the direction of the angle (180° - θ) indicated by A′, but in this case, t ₁
The received light _level output corresponding to
The time t ₃ ′ is different from t ₃ , which causes the angle θ
It becomes possible to determine the direction of (180°-θ).

Therefore, since the speed of the vehicle can be obtained by measurement on the vehicle, the vehicle passing length l ₁ on the rectangular mark 4 can be determined from the vehicle speed and the time t ₁ at the above signal. , hence its length l ₁
The attitude angle .theta. or (180.degree.-.theta.) of the vehicle when it passes the calibration point can be determined using a simple arithmetic device using the known mark dimensions.

Also, the above vehicle speed and the passing time t ₂ above the trapezoidal mark 5
From this length _{l 2 and} the above attitude angle θ or (180° - θ), the passing position of the vehicle at the calibration point (calibration area) can be determined by, for example, Vehicle passing reference point P where the leading edge of rectangular mark 4 intersects the passing locus of the reference point on the vehicle
Alternatively, it can be determined as the absolute coordinates (x, y) of P'.

In order to determine whether it is the attitude angle θ and the passing reference point P, or the attitude angle 180° - θ and the passing reference point P', it is determined from the vehicle speed and the passing time _t3 on the parallelogram mark 6. The vehicle passing length l ₃ on the parallelogram mark 6 is used. The passing length _l3 is different depending on whether the passing direction is A or A', and therefore the passing reference point can be uniquely determined.

As illustrated in FIG. 4, the above-mentioned calibration point mark 3 includes parallel straight line marks 21 and 22 corresponding to the front and rear edges of the rectangular mark 4, and inclined lines corresponding to the rear edge of the trapezoidal mark 5. The line mark 23 and the inclined line mark 24 corresponding to the rear edge of the parallelogram mark 6 may also be used. It can be constituted by a mark having a pair of mutually parallel straight line portions that are not parallel to each other. When the calibration point marks shown in FIG.
2, between marks 22 and 23, and between marks 23 and 24
By measuring the time required for passing between the points, the passing position and attitude angle of the vehicle at the calibration point can be measured in the same way as in the case described above.

In the above measurement, it is necessary for the car to travel in a straight line when passing over the mark, but usually the length l ₁ ,
Since l ₂ and l ₃ are both about 1 to 2 m, it can be considered that the car is traveling in a substantially straight line between them. However, it is not particularly necessary to attach marks to parts where the car runs on curves, and it is preferable to select and attach marks to positions where it is thought that the car will always run in a straight line.

In addition, although the case where the above-mentioned mark is detected by the reflection of light has been explained above, there are various other methods, such as attaching a magnetic mark on the road surface and detecting it with a magnetic detector on the vehicle. Detection means can be employed.

As detailed above, according to the present invention, the passing position and attitude angle of the car at the calibration point can be determined by attaching a simple mark on the running surface of the car and providing a simple detection means on the car. It can be measured in real time on the vehicle.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a mark attached to the running surface of a car to implement the method of the present invention, Fig. 2 is a configuration diagram of a detection means provided in the car, and Fig. 3 is an explanatory diagram of the output of a light receiving element. FIG. 4 is an explanatory diagram showing another example of the structure of the mark. 3...Calibration point mark, 4...Rectangle mark, 5
... Trapezoid mark, 6 ... Parallelogram mark, 10
... Vehicle body, 11 ... Lamp, 12 ... Light receiving element,
21, 22... straight line mark, 23, 24... slant line mark.

Claims (1)

[Claims] 1 At the calibration point on the vehicle's running surface, place a mark with a pair of mutually parallel straight sections oriented approximately perpendicular to the expected direction of travel of the vehicle, and a pair of mutually parallel straight sections that are not parallel to the straight sections. A mark having a straight portion is attached, and as means for detecting the mark, one lamp for illuminating the road surface and one light receiving element for receiving reflected light from the road surface are provided on the vehicle;
This detection means measures the time required to pass between parallel straight sections and non-parallel straight sections of the mark, and based on these times, vehicle speed, and mark dimensions, measures the passing position and attitude angle of the vehicle at the calibration point. A method for measuring the position and attitude angle at a calibration point for recording the traveling trajectory of a vehicle.