JPH03180714A - Method for measuring position and azimuth of moving body - Google Patents

Abstract

PURPOSE:To accurately measure the position and azimuth of the moving body even if there is an obstacle other than a target on a wall surface by equalizing the distance between sensors to the distance between targets and discriminating whether or not one of reflected signals received by the respective sensors overlaps. CONSTITUTION:The distance between the targets A and B is equalized to the distance between the sensors (a) and (b). Consequently, one of reflected signals received by one sensor (a) from the targets A and B and one of reflected signals received by the other sensor (b) from the targets A and B are made to overlap with each other by the traveling of the moving body C. Then when there is the overlap part between the reflected signals from the sensors (a) and (b), it is judged that those reflected signals are from the regular targets and the distance of the straight line connecting the targets A and B at right angles to the straight line connecting the sensors (a) and (b) on the movement side is measured by the sensors (a) and (b). At this time, the deviation angle of the moving body C and the quantity of deviation from a set reference value are measured to accurately measured the position and azimuth of the moving body C even if there is an obstacle other than the targets on the wall surface W.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for measuring the position and orientation of a moving object traveling along a predetermined route [Prior Art] Movement of an automatic guided vehicle, etc. Various methods have been proposed for measuring the position and orientation of a moving body when the body autonomously travels along a predetermined route.

For example, there is a method shown in FIG. This is because a predetermined travel path for the mobile body C is set along a wall surface W, marks are provided on this wall surface W, and, for example, an optical displacement sensor is provided on the mobile body C side, and these optical displacement sensors a and b are installed. It is equipped with a position/direction calculation device to detect the position and direction based on the signals. Optical displacement sensors a and b are installed on the side of the moving body C at two different positions in the front and back direction, and on the wall W side, these two optical displacement sensors are simultaneously facing each other to form a pair of signs A. , B is provided, and 2
Two optical displacement sensors a.

blllllR and the two walls No. 5;jlljA,
B1152 is made equal, and the rVJ distance between the reference position of the traveling path of the moving object and the mark is set so that the side surface of the moving object does not come into contact with the wall surface, and to ensure that measurement can be performed using the optical displacement sensor. shall be determined appropriately.

[Problem to be solved by the invention]

Therefore, measuring the distance to a position mark using an optical displacement sensor can provide the accuracy necessary to correct the deviation from the route due to autonomous driving, but it is also possible to measure the distance with a position mark using an optical displacement sensor. It is necessary to have a wall surface along the travel route, and the wall surface must be free of obstacles such as unevenness. However, buildings such as factories and warehouses in which moving bodies are installed often have pillars and other protrusions on their inner walls, and the protrusions are often placed at irregular intervals.

Therefore, if the inner surface of the wall along the travel path is flat, the moving object's sensor a at the sign A and B positions.

The light beam emitted from b is this 61! IIA, B
The reflected light is reflected by the reflected light detecting means mounted on the moving body, and the reflected signal is detected by the sensor a, as shown in FIG. 1(C).
b are also detected at regular intervals. However, if there is a protrusion gE other than aSa on the wall W as shown in Figure 1 (B), the light beam is also reflected by this protrusion gE, and the reflected signal received by the reflected light detection means is shown in Figure 1 (D). Therefore, it is not possible to determine whether the signal at a position where there is a protrusion on the wall is due to W recognition or not.

It is an object of the present invention to accurately measure the position and orientation of a moving object and to accurately travel along a route even if there are obstacles such as non-a-identical protrusions on the wall surface.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a method for autonomously traveling a mobile object along a preset route, in which II! ll
Then, two sensors that detect this ms are installed on the moving object side, and the distance between the sensors and the distance between the signs are made equal. The gist of the present invention is to identify whether or not the moving body is oriented, measure its position, and measure the direction of the moving body and the amount of deviation thereof.

[For production]

Two sets of 11m markers A and B are placed along the travel route, and markers are also placed on the side of the moving vehicle! l! m-sensor A has two sensors a and b arranged on the side opposite to sensors A and B, and is arranged in pairs at the front and rear in the moving direction of the moving object.

8 and sensors a and b, such as ultrasonic sensors, which are set as a pair, are made equal. As a result, as the moving body travels, the reflected signals sequentially reflected from marks #IA and B by one sensor a, and IIImA by sensor b,
By making one of the reflected signals sequentially reflected from B overlap, if there is an overlap between the reflected signals from the rain sensors a and b, this reflected signal can be converted into the regular 11I! It is determined that the signal is coming from lIl, and the sensor measures the distance of a straight line that intersects at right angles to the straight line connecting the two sensors a and b on the moving side at this time and connects each all. At this time, the deviation angle of the moving object and the deviation amount from the set reference value are measured and recorded on the wall surface.
Even if there are obstacles such as protrusions other than I, the position and orientation of the moving body can be accurately measured.

〔Example〕

The present invention will be explained below based on the illustrated embodiments.

In the figure, C is a moving object such as an automatic guided vehicle, which autonomously travels along a predetermined running path on the floor F using a drive device and running wheels mounted on the moving object.
On the side facing B, the second position Ml in front and behind it is provided with sensors a and b, such as ultrasonic sensors. These sensors a and b come out from sensors a and b and are marked Im
The sign is recognized by detecting the beams reflected by A and B. The sensors a and b are located at equal distances from the center O1 in the longitudinal direction of the moving body, and the distance between the two sensors a and b is 9. In addition, on the wall W side provided along the running route, there are markers IIA, B placed in pairs at predetermined locations on the running route, at positions that can receive and reflect the beam from the sensor of the moving object. will be placed. FIG. 3 shows an embodiment of the m-markers A and B, and the marks A and B may be provided along the wall surface, or cylindrical ones may be provided separately from the floor surface. The distance Q between the pair of marks ImA and B provided at the front and rear of the moving direction of the moving body is made equal to the distance Q between the sensors a and b. The sensors a and b are equipped with reflection detection means for receiving reflected signals reflected from the signs, thereby detecting the position of the moving object.

Therefore, when the mobile body C travels along the travel path and reaches a preset sign position, first the sensor a
The sensor receives the reflected signals from the markers mA and B, and then similarly receives the reflected signal from the sensor b. At this time, if one of the reflected signals from sensors a and b overlaps, it is determined that this reflected signal is from a sign, and the position of the moving body is measured based on this. However, in the case of a reflected signal from a protrusion on the wall W, the reflected signals from the two sensors a and b do not overlap with each other, so in this case, it is not determined that it is a sign.

Let the distance between sensor a and marker 8 be hl, and mark sensor b! 1IAl15 If the separation is h2 and the distance between the center 02 of markers A and H and the center 01 of sensors a and b is L, then the deviation angle θ and deviation amount of the moving object can be calculated from the linear equation. and its direction can be measured.

Note that the signs A and B installed on the wall W side can have a cylindrical, semicircular, triangular, flat, etc. shape that protrudes from the wall surface, but if the shape is not affected by external disturbances, the signs The shape of is not limited.

Furthermore, by using two signs and changing the interval between the signs depending on the location, it is possible to know the absolute location of the location.

Furthermore, by using three or more markers, various information can be sent to the mobile object by combining them.

Also, by measuring the time difference t between the signal of sensor a and the signal of sensor b shown in Figure 1, we can find that the time corresponds to the difference in distance of Q (1-(2)θ) shown in Figure 2. , if the speed of the moving body is ■, then θ can also be calculated from the following formula (% formula %).

〔Effect of the invention〕

According to the present invention, even if there is an obstacle such as a protrusion other than a sign on the wall surface, the difference between [[ and the obstacle such as a protrusion] can be detected by the method of receiving reflected signals by two sensors installed on the moving object. Since it can be identified, it can be applied to any route, and by using two signs and changing the interval between the signs depending on the location, the absolute location of the place can be known, and by using three or more signs, It has advantages such as being able to combine various marks and absolute positions.

[Brief explanation of the drawings] Figure 1 is an explanatory diagram showing a method of measuring the position of a mobile object as it travels along a running route, Figure 2 is an explanatory diagram of measuring the same direction, and Figure 3 is an explanatory diagram showing how to measure the position of a mobile object as it travels along a travel route. An explanatory diagram showing one embodiment, and FIG. 4 is an explanatory diagram of a known example. A and B are 4! X! 1! , a, b are sensors, C is a moving object, and W is a wall surface.

Claims (1)

[Claims] (1) In a method for making a mobile object autonomously travel along a preset route, a sign placed at two positions in front and behind the moving direction of the mobile object along the path and two sensors that detect this sign are moved. It is installed on the side of the body, and the distance between the sensors and the distance between the signs are made equal, and whether the reflected signals received by each sensor overlap or not is used to identify whether the sign is for a moving object or not, and the position of the sign is determined. 1. A position measuring device for a moving object, characterized in that the device measures the orientation of the moving object and the amount of deviation thereof.