JPH0531725B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an unmanned vehicle course deviation detection method for detecting course deviation from a scheduled travel route of an unmanned vehicle. [Conventional technology] Conventionally, the method of guiding an unmanned vehicle to a destination along a predetermined travel route involved estimating the vehicle's current position using a direction detector and travel length measuring device and teaching it in advance. There is a method of automatically steering a vehicle to pass through a planned passing point on a route. The disadvantage of this method is that irregularities in the road surface and slippage in the wheels cause errors in the estimated position of the vehicle, making it impossible to accurately pass through the planned passage point. Therefore, in order to compensate for the shortcomings of the conventional methods, various methods have been proposed in which the estimated position of the vehicle is calibrated intermittently by providing markers intermittently on the travel route to accurately measure the position at low cost. The patent application No. 199007 proposes using the environment such as trees and buildings as markers for position measurement of not only unmanned vehicles but also manned vehicles, but at this stage there is no means to identify these as signs. It is extremely costly and cannot be immediately applied to industry. Japanese Patent Application No. 57-182209 proposes the use of optical retroreflectors stacked in two stages as signs. Furthermore, Japanese Patent Application No. 1987-47508 proposes the use of optical reflectors with distinctive shapes and dimensions as signs. However, both have the drawback that maintenance work, mainly cleaning, requires significant cost and labor, unless the reflector is operated in a clean environment where dirt is unlikely to form. In Japanese Patent Application No. 57-93406, two line segments that are not parallel to each other are provided on the floor along a running path, and the point where the extension lines of the line segments intersect is defined as a fixed position point. The distance between line segments is measured at least twice in the direction intersecting the driving path using a detector mounted on the vehicle. The current position is calculated backwards from the results of these two measurements. The disadvantage of this method is that it requires a detector with a wide lateral field of view, so the cost of the detector is high, even though the cost of the label is low. [Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned circumstances, and provides an unmanned vehicle that has inexpensive signs and detectors and can easily detect course deviations from the planned travel route. The purpose of this invention is to provide a method for detecting course deviation. [Means for Solving the Problems] According to the present invention, a sign with a geometrical characteristic, that is, a sign with three line segments provided across the driving path of an unmanned vehicle, A sign in which only the first and third line segments, excluding line segment 2, are parallel to each other is provided at an appropriate place while driving, and the first and third lines are detected when the detector of the unmanned vehicle passes over the sign. Second
The course deviation of the unmanned vehicle is detected based on the distance between the second and third line segments, or when the vehicle speed is constant, the time required to travel these distances. [Function] Since a sign with the above shape was used, the distance between the first and second line segments when passing over this sign, and the second
The relationship between the distance between the line segment and the third line segment changes,
Thereby, course deviation of the unmanned vehicle can be detected. [Example] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In Figure 1, 1 is an unmanned vehicle, 2 is a sign, and 3
4 is a travel route on which the unmanned vehicle 1 is scheduled to travel, 4 is a trajectory actually traveled by the unmanned vehicle, and 5 is a sensor mounted on the vehicle. The unmanned vehicle 1 has a direction detector and a travel length detector (not shown), and uses these detectors to estimate the current position of the vehicle and is automatically steered to travel on the planned travel route 3. . As shown in FIG. 2, the sign 2 is a linear detected object consisting of three line segments 2a, 2b, and 2c provided across the planned travel route 3. Line segments 2a and 2c are parallel to each other, and line segment 2b is a line segment that connects the end point of line segment 2a and the start point of line segment 2c. This sign 2 is preferably provided on the floor so that the line segments 2a and 2c are orthogonal to the planned travel route 3, and so that the planned travel route 3 passes through the midpoint of each line segment. As the object (material) to be detected that realizes the line segment, a metal plate, metal tape, metal wire, etc. can be used as long as the floor is made of concrete and no metal pieces are buried. Further, as the sensor 5 provided on the vehicle body for detecting the line segment, a metal detector such as an eddy current sensor can be used in the above case. Here, Table 1 shows examples of combinations of sign materials and sensors.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to extremely easily detect a course deviation of an unmanned vehicle with respect to a planned travel route. Note that in a clean work environment such as a semiconductor clean room, an inexpensive system can be obtained by using white line tape as a sign and using a phototransistor as a sensor. Furthermore, in harsh working environments such as mines, a highly durable system can be achieved by embedding steel frames or steel pipes in the road surface and using metal sensors.
Additionally, in environments where aesthetics are important, floor tiles containing ferrite can be used, or metal tape or metal plates can be placed under the floor tiles. Alternatively, if you do not want to modify your floor, a colorless inductive or magnetic material mixed with a colorless hardener can be applied over the floor surface to create a durable and aesthetically pleasing sign. can be installed.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram used to explain the course deviation detection method for an unmanned vehicle according to the present invention, FIG. 2 is an enlarged plan view of the sign in FIG. 1, and FIG. 4 is a plan view showing another embodiment of the sign according to the present invention; FIG. 5 is a diagram of the output waveform of the sensor when passing over the sign in FIG. 4; FIG. 6 is a plan view showing still another embodiment of the sign according to the present invention. 1... Unmanned vehicle, 2, 2'... Sign, 2a, 2'a,
2b, 2'b, 2c, 2c', 6a, 6b... line segment,
3...Planned travel route, 4...Trajectory, 5...Sensor.

Claims (1)

[Claims] 1 The first and third line segments, excluding the second line segment in the center, are three line segments provided across the driving path of unmanned vehicles.
A sign in which only the line segments are parallel to each other is provided at an appropriate location on the driving route, and the distance between the first and second line segments detected by the detector of the unmanned vehicle when passing over the sign, and the distance between the second and second line segments are A method for detecting course deviation of an unmanned vehicle, characterized in that the course deviation of the unmanned vehicle is detected based on the distance between the third line segment or the time required for traveling these distances when the vehicle speed is constant.