JPH04362709A - Attitude angle detector for unmanned vehicle - Google Patents

Abstract

PURPOSE:To detect the attitude angle of an automatic vehicle even in such a place where a correction means like a reflecting plate, a mark, etc., cannot be set on the floor surface. CONSTITUTION:An unmanned vehicle running autonomously in a prescribed area is provided together with a projector 3 which emits the light to the prescribed area. The vehicle is provided with a detector which receives the light from the projector 3 and detects the attitude angle of the vehicle. The detector contains a beam splitter 5 which is fixed at 45 deg. to the axial line along which the vehicle runs straight and the photodetectors 7 and 8 which are provided in the areas correctly projected from the splitter 5 in the axial line direction and in the direction orthogonal to the axial line. The photodetector 8 is set apart from the photodetector 7 with a prescribed offset distance (c) secured from a position where the photodetector 7 is moved in surface symmetry with the splitter 5 defined as a reference surface. In such a constitution, the attitude angle of the vehicle can be detected without setting such correction means like a reflecting plate, a mark, etc., on the floor surface.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an attitude angle detector for an unmanned vehicle, and particularly to one that can be suitably employed in a mobile robot that reciprocates over a wide area.

0002

[Prior Art] Conventionally, in the driving control of an unmanned vehicle (hereinafter simply referred to as a vehicle) that runs autonomously, methods for detecting the attitude angle of the vehicle body include a gyro or a method that calculates from the rolling distance of the wheels. Are known. However, since errors accumulate in these calculated values as the gyro is used or the distance traveled increases, it is necessary to provide a device to correct these errors.

[0003] As such means, for example, there is a method in which a reflector serving as a reference is installed in the travel route of the vehicle, and the distance between the reflector and the vehicle body is measured with a range finder to determine the attitude angle; A predetermined mark is placed on the floor surface of the machine, and the mark is captured as binarized data using an imaging device, etc.
A method of determining the attitude angle of a vehicle body by performing predetermined image processing has been proposed.

0004

[Problems to be Solved by the Invention] However, the attitude angle correcting means provided with a reflector or mark on the floor surface, for example,
They cannot be used in cleaning robots that travel back and forth across wide areas such as gymnasiums and multipurpose halls to clean the floors, as they become obstacles while running. Therefore, when the work area of the cleaning robot is wide, there is a problem that the attitude angle cannot be corrected over a long distance, and the running accuracy decreases. Especially when the running vehicle is a cleaning robot,
There is also the disadvantage that uncleaned areas occur.

[0005] The present invention was made in view of this problem, and its purpose is to detect the attitude angle of a traveling vehicle even in places where it is not possible to provide correction means such as reflectors or marks on the floor. The object of the present invention is to provide an attitude angle detector that makes it possible.

[0006]

[Means for Solving the Problems] The present invention provides an unmanned vehicle that autonomously travels in a predetermined area, and at least one floodlight that emits light or laser light toward the area from outside the area. In addition, the unmanned vehicle is provided with a detector that detects the attitude angle of the vehicle body by receiving the light from the projector or the laser beam, and the detector is arranged along the axis along which the unmanned vehicle travels straight. A beam splitter is fixed at an angle of 45 degrees to the beam splitter, and a one-dimensional light-receiving element is provided in a region orthogonally projected from the beam splitter in the axial direction and in a direction orthogonal to the axis, and one one-dimensional light-receiving element is characterized in that it is provided at a predetermined offset distance from a position where another one-dimensional light receiving element is moved plane-symmetrically with the beam splitter as a reference plane.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of the system in which the invention is used;
FIG. 2 shows the same block diagram, and shows a predetermined running area 1, a running vehicle 2 autonomously running in the running area 1, and a light or laser beam directed toward the running area 1 from outside the running area 1. (hereinafter simply referred to as light).

The traveling vehicle 2 detects the rolling distance of wheels (not shown) with an encoder 11, calculates its own position and attitude angle θn with a CPU 13, and runs a predetermined travel program based on a predetermined travel program. This example shows a vehicle that can travel on a trackless course, and in this example, a vehicle that basically travels back and forth in the travel area 1 and travels throughout the entire area is exemplified. The traveling vehicle 2 is provided with an attitude angle detector 4 capable of receiving light 10 from a light projector 3 and measuring the attitude angle of the vehicle body, which will be described later.

[0009] Light 1 sent out from each light projector 3...
0 is arranged so as to be orthogonal to an axis 9 (hereinafter simply referred to as axis 9) corresponding to a long distance in the traveling course of the traveling vehicle 2, and in this example, beam light is emitted at three locations in total. They are arranged at predetermined intervals.

The attitude angle detector 4 according to the present invention is constructed by disposing a beam splitter 5 and a pair of one-dimensional light receiving elements (hereinafter simply referred to as light receiving elements) 7 and 8 in a box-shaped case 6. has been done. Furthermore, in a state where the traveling vehicle 2 has zero attitude angular displacement with respect to the axis 9, the beam splitter 5
It is fixed to the case 6 so as to form an angle of 45 degrees with respect to the optical axis emitted by the projector 3. Furthermore, light receiving elements 7 and 8 are provided in areas where the beam splitter 5 is orthographically projected in the vertical and horizontal directions in the figure, respectively. Further, as shown in FIG. 3, one light receiving element 8 is provided at a predetermined offset distance c from a position 7A where the other light receiving element 7 is moved plane-symmetrically with respect to the beam splitter 5 as a reference plane. There is. Note that the above-mentioned light receiving elements 7 and 8 and beam splitter 5 are arranged in the same horizontal plane.

Electrical signals obtained by each of the light receiving elements 7 and 8 are sent to the CPU 13 via the A/D converter 12. Further, a signal from an encoder 11 that detects the distance traveled by the vehicle 2 is input to the CPU 13 .

Next, the operation of the present invention will be explained. FIG. 4 shows a control flowchart of the traveling vehicle, and based on this, the traveling vehicle 2 initializes the attitude angle θn (θ
n→0), the vehicle then runs on a running course based on its own running program. At this time, the CPU 13 uses the distance detected by the encoder 11 at each sampling time.
The attitude angular displacement Δθs of the vehicle body is successively determined, and the attitude angular displacement Δθs is successively integrated to obtain the attitude angle θn, and the steering circuit 14 controls the control object 15 such as the steering motor so as to reduce this. Furthermore, “n” in “θn” is
means sequential value.

As shown in FIG. 3, the projector 3
When the light emitted from the vehicle 2 is received by the attitude angle detector 4 provided on the vehicle 2, a portion of the light 10 is split by the beam splitter 5 and changes its course downward.
The light is received by one light receiving element 7, and the remaining light is transmitted through the beam splitter 5 and received by the other light receiving element 8. The electrical signals obtained by each of the light receiving elements 7 and 8 are sent to the CPU 13 via the A/D converter 12, respectively. Here, if the angle between the light 10 emitted by the projector 3 and the reference axis 16 in the vehicle width direction of the traveling vehicle (hereinafter referred to as measurement attitude angle) is θp, θp is

It is obtained by [Equation 1]. However, a is the distance from the left end of the light receiving element 7 to the light receiving position, b is the distance from the lower end of the light receiving element 8 to the light receiving position, and c is the offset distance of the light receiving element 8.

[Math 1]

[0014] Once the measured attitude angle θp is obtained, the current CP
In the value of the vehicle body attitude angle θn obtained by the calculation in U13,
Substitute the measured attitude angle θp (θp→θn). Therefore, after the attitude angle θn is replaced with the measured attitude angle θp, the attitude angle displacement Δθs found from the travel distance detected by the encoder 11 is added to or subtracted from the measured attitude angle θp.

Next, a second embodiment of the present invention will be explained. As shown in FIG. 5, in order to deal with the case where the light emitted from the projector 3 is other than a beam light, each demultiplexed light from the beam splitter 5 is input to the light receiving elements 7 and 8 via lenses 17 and 18. It is configured to allow In this case as well, the lens 18 and the light receiving element 8 on one side may be arranged with an offset distance c between them.

[0016]

[Effects of the Invention] By adopting the present invention, there is no need to provide correction means such as reflectors or marks on the floor surface, and the attitude angle of the running vehicle can be corrected. A traveling vehicle can be guided to a predetermined traveling course. In particular, when adopted in a cleaning robot, the posture angle can be corrected even in places such as gymnasiums and halls where the posture angle correction of the cleaning robot cannot be performed for a long period of time. The inconvenience of the area being generated can be solved. Furthermore, since the attitude angle can be corrected every time the vehicle passes through the light from the projector, it is possible to further improve the running accuracy by increasing the number of projectors installed.

[Brief explanation of drawings]

1 is a schematic diagram of the system in which the invention is used; FIG.

FIG. 2 is a block diagram of a system in which the invention is used.

FIG. 3 is a conceptual diagram for explaining the principle of an attitude angle detector.

FIG. 4 is a control flowchart of an unmanned vehicle.

FIG. 5 is a conceptual diagram showing another embodiment of the present invention.

[Explanation of symbols]

2　Unmanned vehicle 3. Floodlight 4 Attitude angle detector 5 Beam splitter 7 One-dimensional light receiving element 8 One-dimensional light receiving element 17 Lens 18 Lens

Claims (1)

[Claims] Claim 1: An unmanned vehicle that autonomously travels in a predetermined area; and at least one floodlight that emits light or laser light toward the area from outside the area; is provided with a detector that detects the attitude angle of the vehicle body by receiving the light from the projector or laser light, and the detector is arranged at an angle of 45 degrees with respect to the axis along which the unmanned vehicle travels straight. A fixed beam splitter and a one-dimensional light-receiving element are provided in areas orthogonally projected from the beam splitter in the axial direction and in a direction orthogonal to the axis, and one one-dimensional light-receiving element is connected to the other one-dimensional light-receiving element. An attitude angle detector for an unmanned vehicle, characterized in that the light receiving element is provided at a predetermined offset distance from a position where the light receiving element is moved plane symmetrically with respect to the beam splitter as a reference plane.