Obstacle detection method and obstacle detection system

Abstract

To provide an obstacle detection method and an obstacle detection system capable of improving the accuracy of detecting the presence or absence of an obstacle even when the posture of a mobile object changes.SOLUTION: In an obstacle detection method that sets at least one detection area S in advance in the area around a reflection point Pn where an electromagnetic wave is reflected when there is no obstacle, emits an electromagnetic wave toward the detection area S while changing the irradiation angle from a transmission unit 9 installed on a mobile body 2, receives the reflected wave of this electromagnetic wave by a receiving unit 10, and determines the presence or absence of an obstacle according to the reflected wave reflected inside the detection area S by a determination mechanism 13, the position of the detection area S is corrected according to the posture of the mobile body 2 with respect to a running surface 8 on which the mobile body 2 runs.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to an obstacle detection method and an obstacle detection system that are installed on a moving body such as a vehicle traveling on a driving surface and detect the presence or absence of obstacles around the moving body, and more particularly to an obstacle detection system and an obstacle detection method that can improve the accuracy when determining the presence or absence of an obstacle. [Background technology]

[0002] Various obstacle detection systems have been proposed that are installed on a gantry crane and detect surrounding obstacles (see, for example, Patent Document 1).

[0003] The obstacle detection system described in Patent Document 1 was configured to determine the presence or absence of an obstacle based on reflected light from inside a preset detection area, and was able to detect the presence of an obstacle even if the obstacle was made of a material that did not easily reflect laser light. In addition, by devising the shape of the detection area, the obstacle detection system was able to accurately detect the presence or absence of an obstacle even if a moving object such as a gantry crane rose and fell.

[0004] The obstacle detection system described in Patent Document 1 has a detection area that has ranges in both the horizontal and vertical directions, and the wider the vertical range is set, the easier it is to respond to the undulations of a moving object. However, there is a problem in that if the detection area is set wide in the vertical direction, it becomes difficult to detect relatively small obstacles in the vertical direction. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-105822 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in consideration of the above problems, and its purpose is to provide an obstacle detection method and an obstacle detection system that can improve the accuracy of detecting the presence or absence of an obstacle even when the attitude of a moving body changes. [Means for solving the problem]

[0007] In order to achieve the above object, the obstacle detection method of the present invention includes a step of setting at least one detection area in advance in a peripheral area of ​​a reflection point where an electromagnetic wave is reflected when there is no obstacle, irradiating an electromagnetic wave toward the detection area while changing an irradiation angle from a transmitter installed on a moving body, receiving a reflected wave of the electromagnetic wave at a receiver, and determining whether or not an obstacle is present based on the reflected wave reflected inside the detection area by a determination mechanism, and correcting the position of the detection area based on the attitude of the moving body with respect to the traveling surface on which the moving body is traveling. After the determination mechanism determines that an obstacle is present, the determination mechanism performs a second determination to determine the presence or absence of an obstacle again based on the reflected wave reflected outside the detection area. It is characterized by:

[0008] The obstacle detection system of the present invention includes a transmitter that is installed on a moving body and emits electromagnetic waves while changing the irradiation angle, a receiver that receives reflected waves of the electromagnetic waves, a detection area setting mechanism that presets at least one detection area in a peripheral area of ​​a reflection point where the electromagnetic waves are reflected when there is no obstacle, and a determination mechanism that determines the presence or absence of an obstacle based on the reflected waves reflected inside the detection area, and further includes an attitude acquisition mechanism that acquires the attitude of the moving body with respect to a traveling surface on which the moving body travels, and a correction mechanism that corrects the position of the detection area based on a value acquired from the attitude acquisition mechanism. and the determination mechanism is configured to perform a second determination to determine the presence or absence of an obstacle again based on the reflected wave reflected outside the detection area after determining that an obstacle is present. It is characterized by: Effect of the Invention

[0009] According to the obstacle detection method and obstacle detection system of the present invention, the position of the detection area can be corrected according to the attitude of the moving object relative to the traveling surface. Since the detection area can be set in a relatively narrow range along the traveling surface, it is advantageous in improving the accuracy of detecting the presence or absence of an obstacle. [Brief description of the drawings]

[0010] [Figure 1] 1 is an explanatory diagram illustrating, in perspective, a gantry crane on which an obstacle detection system of the present invention is installed; [Diagram 2] FIG. 2 is an explanatory diagram illustrating a gantry crane in a plan view. [Diagram 3] 1 is an explanatory diagram showing a configuration of an obstacle detection system according to the present invention; [Figure 4] 1 is an explanatory diagram illustrating, in a plan view, reflection points on a traveling surface when there are no obstacles; FIG. [Diagram 5] 4 is an explanatory diagram illustrating a state when the obstacle detection system of FIG. 3 detects an obstacle. [Figure 6] 1 is an explanatory diagram illustrating, in a plan view, reflection points on a traveling surface when an obstacle is present; FIG. [Figure 7] FIG. 1 is an explanatory diagram illustrating a state in which a gantry crane is tilted about a central axis in the lateral travel direction. [Figure 8] FIG. 1 is an explanatory diagram illustrating a state in which a gantry crane is tilted with the direction of movement as its central axis. [Figure 9] 1 is an explanatory diagram illustrating a state in which the travel surface is inclined with the lateral direction as the central axis. FIG. [Figure 10] FIG. 11 is an explanatory diagram illustrating a state in which a plurality of detection regions are set. [Figure 11] 1 is an explanatory diagram illustrating a state in which the travel surface is tilted with the movement direction as the central axis. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The obstacle detection method and obstacle detection system of the present invention will be described below based on the embodiment shown in the drawings. In the drawings, the moving direction of a moving object is indicated by arrow y, the lateral direction perpendicular to the moving direction y is indicated by arrow x, and the up-down direction is indicated by arrow z.

[0012] 1, a gantry crane, which is a mobile body 2 on which an obstacle detection system 1 of the present invention is installed, includes a traveling device 3 that travels in a traveling direction y, four leg members 4 that are arranged above the traveling device 3 and extend in a vertical direction z, two beam members 5 that extend in a lateral direction x and connect the upper ends of the leg members 4 that face each other in the lateral direction x, a trolley 6 that is configured to be movable in the lateral direction x along the beam members 5, and a hoist 7 that is suspended from the trolley 6 by a wire rope. The gantry crane that constitutes the mobile body 2 can handle containers while traveling on a traveling surface 8 in the traveling direction y.

[0013] The obstacle detection system 1 has a transmitter 9 that irradiates electromagnetic waves, such as laser light, toward the traveling surface 8, and a receiver 10 that receives the reflected waves reflected by the traveling surface 8. The receiver 10 is disposed near the transmitter 9. In this embodiment, the transmitter 9 and the receiver 10 (hereinafter sometimes collectively referred to as the transmitter 9, etc.) are disposed below the four leg members 4 and in the vicinity of the traveling device 3. The location at which the transmitter 9, etc. are disposed is not limited to the above, and they can be disposed appropriately in other locations, such as the traveling device 3 and the beam member 5.

[0014] The transmitter 9 is configured to scan the laser beam in a range from the front to the back of the gantry crane in the direction of travel y, which is the moving body 2. For the sake of explanation, the direction of irradiation of the laser beam is shown by a dashed line in Fig. 1. Alternatively, as shown in Fig. 2, the transmitter 9 may be configured to irradiate the laser beam in a state that spreads in a lateral direction x that crosses the direction of travel y at a right angle.

[0015] A configuration may be adopted in which laser light is not emitted from the transmitter 9 installed on the rear side in the moving direction y of the gantry crane. Also, for example, one transmitter 9 installed on the beam member 5 may be configured to irradiate laser light to the front side and the rear side in the moving direction y of the gantry crane.

[0016] The moving body 2 on which the obstacle detection system 1 is installed is not limited to a gantry crane. The obstacle detection system 1 can be installed on a moving body 2 that moves on a plane or in space, for example, on a vehicle such as a container chassis or on a quay crane. The obstacle detection system 1 may also be installed on the hoisting device 7 or trolley 6 of a gantry crane or a quay crane.

[0017] As illustrated in FIG. 3, the obstacle detection system 1 includes a transmitter 9 and a receiver 10. The transmitter 9 is not limited to a configuration that irradiates laser light. The transmitter 9 may have a configuration that irradiates electromagnetic waves including light. In this specification, light including ultraviolet light, visible light, and infrared light, and radio waves including microwaves, millimeter waves, and long waves may be collectively referred to as electromagnetic waves. The transmitter 9 may have a configuration that irradiates light such as infrared light or radio waves such as millimeter waves. The transmitter 9 may have a configuration that irradiates sound waves. The transmitter 9 may also have a configuration that irradiates multiple types of electromagnetic waves or a combination of electromagnetic waves and sound waves. The receiver 10 may have a configuration that can receive reflected waves of electromagnetic waves or sound waves irradiated from the transmitter 9.

[0018] The obstacle detection system 1 includes a comparison mechanism 11 that acquires data from the receiving unit 10, a detection area setting mechanism 12 that sends data to the comparison mechanism 11, a determination mechanism 13 that acquires data from the comparison mechanism 11 and determines the presence or absence of an obstacle, a threshold setting mechanism 14 that adjusts a threshold used by the determination mechanism 13, and a control mechanism 15 that controls the moving body 2 based on the determination result of the determination mechanism 13. The obstacle detection system 1 also includes an attitude acquisition mechanism 16 that acquires the attitude of the moving body 2, and a correction mechanism 17 that acquires data from the attitude acquisition mechanism 16. Note that the comparison mechanism 11, the threshold setting mechanism 14, and the control mechanism 15 are not essential requirements of the present invention.

[0019] The obstacle detection system 1 first irradiates a laser beam from the transmitter 9 toward the travel surface 8. The transmitter 9 irradiates the laser beam radially (in a fan shape) multiple times in sequence by rotating a mirror or the like. The receiver 10 acquires the time tn from the irradiation of the laser beam to the reception of the reflected wave by the receiver 10 for each angle θn when the laser beam is irradiated from the transmitter 9. Here, the angle θn represents the inclination of the traveling direction of the laser beam with respect to the vertical direction z.

[0020] The transmitter 9 and the receiver 10 measure the distance from the transmitter 9 to the traveling surface 8. The transmitter 9 and the receiver 10 can be configured, for example, as a three-dimensional laser scanner. For example, a three-dimensional laser scanner can be used that has a configuration in which laser light is irradiated in a state where it is overlapped in 24 layers in the lateral direction x, and each laser light independently rotates around the lateral direction x as a central axis. In this three-dimensional laser scanner, the resolution of the angle θn is set to, for example, 0.125 degrees to 1.000 degrees, and the rotation speed of the mirror for rotating the laser light is set to, for example, 1 to 10 Hz. The transmitter 9 and the receiver 10 may be configured as a three-dimensional lidar or a three-dimensional millimeter wave radar. The transmitter 9 and the receiver 10 may be configured as a sensor with a two-dimensional measurement range, such as a two-dimensional laser scanner in which a single-layer laser rotates independently. The configuration of the transmitter 9 and the receiver 10 is not limited to the above, and may be configured to irradiate a plurality of electromagnetic waves in a predetermined range and receive reflected waves. For example, the transmitter 9 and the receiver 10 may be configured as a sensor without a rotating mirror.

[0021] The receiving unit 10 can use data in the range where the angle θn is equal to or greater than 0 degrees and equal to or less than 90 degrees, but does not include 90 degrees. It is preferable that the receiving unit 10 use data in the range where the angle θn is equal to or greater than 0 degrees and equal to or less than 60 degrees. The larger the range of the angle θn, the more distant an obstacle from the moving body 2 can be detected, so it is preferable to set the upper limit of the range of the angle θn closer to 90 degrees when the speed of the moving body 2 is high.

[0022] For example, in the case of a three-dimensional laser scanner in which the range of angle θn is set to 0 degrees to 60 degrees, the resolution is set to 0.125 degrees, and the rotation speed is set to 5 Hz, the receiving unit 10 obtains 2400 points of measurement data per second per layer. In other words, the receiving unit 10 obtains 2400 points of data per second that combines angle θn and time tn. In the case of a three-dimensional laser scanner with 24 layers, the receiving unit 10 obtains 57600 points of data per second.

[0023] Next, the processing of data acquired as a result of irradiation of the laser light per layer will be described. As illustrated in FIG. 3, the reflection points Pn at which the laser light per layer is reflected by the traveling surface 8 are arranged in a straight line along the scanning direction of the laser light. Hereinafter, this straight line may be referred to as a reference line 18. This reference line 18 is an imaginary straight line formed on the traveling surface 8. It can also be said that the reference line 18 is a collection of multiple reflection points Pn formed by the laser light being reflected by the traveling surface 8. Since this reference line 18 is formed in the range where the laser light is reflected by the traveling surface 8, the relative position of the reference line 18 with respect to the transmitter 9 is fixed. Therefore, the reference line 18 moves in the moving direction y as the moving body 2, such as a gantry crane, moves.

[0024] In the detection area setting mechanism 12, a detection area S is set in advance. The detection area S is set in advance in a peripheral area of ​​a reflection point Pn where an electromagnetic wave is reflected when there is no obstacle. The detection area S is a quadrangular area formed on a plane consisting of the moving direction y and the vertical direction z, and is set as a relative position with respect to the transmitter 9 and the like. In this embodiment, the detection area S is a rectangular area surrounded by a pair of long sides 19a, 19b set in a direction along the moving direction y of the moving body 2 and above and below the reflection point Pn, i.e., the reference line 18, and a pair of short sides 20a, 20b connecting the opposing ends of the pair of long sides 19a, 19b and extending in the vertical direction z. The shape of the detection area S is not limited to the above and can be set appropriately. For example, it can be set to a shape including a polygon or a curve.

[0025] In this embodiment, the length of the short sides 20a, 20b of the detection area S can be set, for example, within a range of ±100 mm in the vertical direction z around the reference line 18. In the case of a gantry crane with rubber tires, the rubber tires may expand and contract in the vertical direction z due to the load of the container. As the rubber tires expand and contract, the transmitter 9 and the like move in the vertical direction z, and therefore the detection area S also moves in the vertical direction z. The length of the short sides 20a, 20b is set within a range in which the reference line 18 falls inside the detection area S, even if the detection area S moves in the vertical direction z.

[0026] The length of the long sides 19a, 19b can be set in the horizontal direction within a range of several meters to several tens of meters. The lengths of the long sides 19a, 19b are set to be longer than or the same length as the reference line 18. In other words, the range of the detection area S is set so that the reference line 18 is always inside the detection area S.

[0027] The detection area S has a fixed position relative to the transmitter 9. Therefore, the detection area S moves in the moving direction y in accordance with the movement of the moving body 2, such as a gantry crane, in the same manner as the reference line 18. In this embodiment, since the reference line 18 is parallel to the moving direction y, the detection area S is a plane parallel to the moving direction y.

[0028] The comparison mechanism 11 is configured to compare a reflection point Pn of the laser light emitted from the transmitter 9 with the detection area S to determine whether the reflection point Pn is inside or outside the detection area S. For example, when the laser light is emitted at an angle θ1, two intersection points p1, p1' between the irradiation direction of this laser light and the boundary line of the detection area S can be determined in advance. In other words, the range of the two intersection points pn, pn' with the detection area S is determined for each angle θn.

[0029] Specifically, the intersection points pn, pn' are set by a combination of the time Tn, Tn' from when the laser light is emitted from the transmitting unit 9 until the reflected wave is received by the receiving unit 10, and the irradiation angle θn of the laser light.

[0030] If the distance from the receiving unit 10 to the reflection point P1 is between the distance from the receiving unit 10 to the intersection p1 and the distance from the receiving unit 10 to the intersection p1', the comparison mechanism 11 determines that the reflection point P1 is inside the detection area S. Based on the data of the detection area S from the detection area setting mechanism 12, the comparison mechanism 11 determines whether each of the multiple reflection points Pn is inside or outside the detection area S.

[0031] Specifically, if the time tn from the irradiation of the laser light to the acquisition of the reflected wave is between the time Tn corresponding to the intersection point pn and the time Tn' corresponding to the intersection point pn', the comparison mechanism 11 determines that the reflected wave is from inside the detection area S.

[0032] The comparison mechanism 11 sends an on (ON) signal to the judgment mechanism 13 when the reflection point Pn is located inside the detection area S, and sends an off (OFF) signal to the judgment mechanism 13 when the reflection point Pn is located outside the detection area S.

[0033] The determination mechanism 13 determines the presence or absence of an obstacle according to the ratio of ON and OFF signals sent from the comparison mechanism 11. For example, if the receiving unit 10 obtains 2400 points of measurement data per second, 2400 points of ON and OFF signals per second are sent from the comparison mechanism 11 to the determination mechanism 13.

[0034] The determination mechanism 13 calculates the ratio of the number of ON signals to the total number of ON signals and OFF signals sent from the comparison mechanism 11 per unit time as the fulfillment rate. The determination mechanism 13 also stores a predetermined threshold value for the fulfillment rate. The threshold value for the fulfillment rate can be set to, for example, 90%.

[0035] When there is no obstacle, the reflection point Pn is located along the reference line 18 and inside the detection area S, so 2400 ON signals per second are sent to the determination mechanism 13. At this time, the fulfillment rate is 100%, which is more than 90% of the threshold value.

[0036] Since all of the laser light emitted from the transmitter 9 is reflected by the traveling surface 8, it can be seen that there is no obstacle blocking the laser light between the transmitter 9 and the traveling surface 8. When the fulfillment rate is equal to or greater than a threshold value, the determination mechanism 13 determines that there is no obstacle and that it is safe. The determination mechanism 13 is not limited to a configuration that makes a determination every second, and the frequency of the determination can be set as appropriate, for example, to make a determination every 0.2 seconds.

[0037] At this time, the obstacle detection system 1 is in a state where it can confirm the entire reference line 18. In other words, the obstacle detection system 1 is in a state where it can see the travel surface 8.

[0038] As shown in Fig. 4, when the transmitter 9 and receiver 10 are configured as a three-dimensional laser scanner that irradiates laser light in nine layers, the reflection points Pn are distributed not only in the moving direction y but also in the lateral direction x. In this embodiment, nine laser beams are irradiated from the transmitter 9 to the traveling surface 8. The laser beams in each layer form reference lines 18, and the reference lines 18 are in a state of spreading forward in the traveling direction of the moving body 2. In this embodiment, the reflection points Pn distributed on the traveling surface 8, which is a plane spreading in the lateral direction x and the moving direction y, form an approximately fan-shaped shape. For the sake of explanation, the range of the detection area S is shown by a dashed line in Fig. 4.

[0039] At this time, the detection area S is set as a space having a width in the horizontal direction x in addition to the moving direction y and the vertical direction z. For example, the detection area S is set in a rectangular parallelepiped shape. In this embodiment, for example, the reflection points P1-1 to P1-5 of the laser light in the first layer are processed as being inside the detection area S. The reflection point P1-6 outside the detection area S is excluded in advance from the data processed by the comparison mechanism 11. The reflection points P2-1 to P2-6 of the laser light in the second layer are processed by the comparison mechanism 11 as being inside the detection area S. If six reflection points Pn are obtained per layer, 54 reflection points Pn are obtained in nine layers in the embodiment of FIG. 4. If there is no obstacle, the reflection points Pn at which the laser light is reflected inside the detection area S are 52 points. If there is no obstacle during measurement, 52 ON signals are sent to the judgment mechanism 13. At this time, the fulfillment rate is 100%. For the sake of explanation, the reflection points Pn located outside the detection area S are shown by dashed lines in FIG. 4.

[0040] As illustrated in Figs. 5 and 6, when an operator 21 is present in front of the moving body 2, part of the laser light emitted from the transmitter 9 is blocked by the operator 21 and does not reach the travel surface 8. If the laser light is absorbed by the operator 21, no reflected wave is obtained. Even if the laser light is reflected by the operator 21, the reflected wave is from outside the detection area S. In either case, the presence of the operator 21 reduces the number of reflected waves obtained from inside the detection area S. When the reflection point Pn of the reflected wave is outside the detection area S, an OFF signal is output from the comparison mechanism 11 to the determination mechanism 13. In Figs. 5 and 6, the range of the detection area S is shown by a dashed line for the sake of explanation. Also, for the sake of explanation, the range inside the detection area S and below the travel surface 8 is shaded.

[0041] As shown in FIG. 6, the receiver 10 cannot receive reflected waves from inside the detection area S in the shadow of the worker 21. Therefore, the obstacle detection system 1 cannot confirm the reference line 18 in the position behind the worker 21. The number of reflection points Pn obtained from inside the detection area S is, for example, 38 points, and the fulfillment rate is about 73%. The fulfillment rate is a value smaller than the preset threshold value of 90%. In such a case, the obstacle detection system 1 determines that an obstacle is present on the reference line 18. For the sake of explanation, in FIG. 6, the reflection points Pn that the laser light cannot reach because they are blocked by obstacles are shown by dashed lines.

[0042] If the obstacle detection system 1 is equipped with a control mechanism 15, the control mechanism 15 may be configured to perform control to slow down or stop the traveling speed of a moving body 2, such as a gantry crane, based on the determination by the determination mechanism 13 that an obstacle is present.

[0043] Since the obstacle detection system 1 is not configured to directly detect obstacles, it can determine the presence of an obstacle even when the reflected wave cannot be obtained because the obstacle absorbs the laser light, which is advantageous for improving the accuracy in determining the presence or absence of an obstacle.

[0044] In conventional obstacle detection systems, the presence of an obstacle was detected by the reflected waves from the obstacle, so in order to improve the accuracy of the obstacle detection system, it was necessary to increase the output of the laser light to make it easier to obtain the reflected waves, or to improve the sensitivity of the receiver 10 so that even a small amount of reflected waves could be detected. A great deal of effort was spent to directly search for obstacles whose existence was uncertain. In addition, the more the sensitivity of the system was improved, the greater the problem of detecting rain or insects that are not obstacles as obstacles. Furthermore, if the laser light could no longer be emitted or the reflected waves could not be detected due to some kind of malfunction, there was a problem in which the obstacle could not be detected even if it was present and the vehicle was determined to be safe.

[0045] The obstacle detection system 1 of the present invention is configured to detect the absence of an obstacle. Specifically, it is configured to check the percentage at which an imaginary straight line formed on the travel surface 8, i.e., a reference line 18, can be detected. Since it is sufficient to detect the reference line 18, there is no need to increase the output of the laser light or improve the sensitivity of the receiving unit 10 to improve the accuracy of the obstacle detection system 1. The obstacle detection system 1 is configured to determine the possibility that an obstacle is absent, and can determine whether there is a high possibility that there is no obstacle and therefore safety is high, or whether there is an obstacle and therefore safety is low, depending on the fulfillment rate.

[0046] The obstacle detection system 1 is configured to determine the presence or absence of an obstacle based on the reflected waves reflected inside the detection area S. Therefore, when the reflected waves cannot be received due to a malfunction of the transmitting unit 9 or the receiving unit 10, the system will not erroneously determine that there is no obstacle. Therefore, the obstacle detection system 1 is a system that functions on the safe side, which is advantageous in improving safety during the movement of the mobile object 2.

[0047] Conventional obstacle detection systems directly search for obstacles whose existence is uncertain, and therefore even a slight reaction would result in the moving body being stopped as an obstacle is present. In contrast, in the present invention, even if one laser beam is reflected outside the detection area S due to rain or insects, 57,599 points out of 57,600 points of data sent to the determination mechanism 13 will be on, resulting in a fulfillment rate of 90% or more, and thus problems such as emergency stops of the moving body 2, such as a gantry crane, can be avoided.

[0048] If the obstacle detection system 1 is equipped with a threshold setting mechanism 14, it becomes possible for a crane operator or the like to adjust the threshold value as appropriate depending on the weather, etc. In fine weather, the threshold value can be set to, for example, 90%. In heavy rain, the threshold value can be set to, for example, 80%. Even if a large amount of laser light is reflected outside the detection area S due to rain, the mobile body 2 such as a gantry crane can be allowed to travel. Even in this case, when a worker is above the reference line 18, the fulfillment rate further decreases to a low value such as 70%, so it is possible to detect the presence of the worker.

[0049] By installing the comparison mechanism 11, one bit of data, either on or off, is sent to the determination mechanism 13. Because the amount of data sent to the determination mechanism 13 is extremely small, this is advantageous in saving on the amount of memory required by the determination mechanism 13 when making a determination. If the mobile object 2 is configured as a gantry crane, for example, the determination mechanism 13 can be incorporated into a sequence controller (PLC) that controls the operation of the gantry crane. Since the sequence controller must also process control of the travel and loading and unloading of the gantry crane, it is desirable to have as little memory as possible occupied by the determination mechanism 13.

[0050] Since the amount of memory occupied by the determination mechanism 13 can be suppressed, it is possible to increase the number of laser beams per unit time irradiated by the transmitting unit 9 and to increase the frequency of determination by the determination mechanism 13. It is also possible to increase the number of layers of laser beam irradiated from the transmitting unit 9. Even if the transmitting unit 9 is configured with a three-dimensional laser scanner in which the laser beam is irradiated in 24 overlapping layers and the mirror rotation speed in each layer is 10 Hz, the determination can be made by the determination mechanism 13 without significantly increasing the amount of memory occupied by the sequencer.

[0051] Assume that the determination mechanism 13 can process, for example, 57,600 pieces of data per second when it is not equipped with the comparison mechanism 11. When it is equipped with the comparison mechanism 11, the determination mechanism 13 can process, for example, 10 times as many pieces of data, 576,000 pieces of data, per second.

[0052] Furthermore, the installation of comparison mechanism 11 reduces the amount of data to be processed by determination mechanism 13, thereby shortening the time required for determination by determination mechanism 13. Even if the resolution of the three-dimensional laser scanner constituting transmission unit 9 is relatively high and the rotation speed is relatively fast, determination by determination mechanism 13 can be performed with almost no delay.

[0053] Even if the moving body 2 is, for example, a fast-moving object such as an automobile, the safety can be appropriately judged without delay. This is advantageous in suppressing the occurrence of malfunctions such as an emergency stop of the moving body 2 not being made in time. The speed at which the judgment is made by the judgment mechanism 13 can be made relatively fast compared to the moving speed of the moving body 2. Therefore, measures such as setting the fulfillment rate threshold higher than necessary to avoid collision of the moving body 2 with an obstacle or the like are not required.

[0054] The comparison mechanism 11 is not an essential requirement for the obstacle detection system 1 of the present invention. If the comparison mechanism 11 is not provided, the system may be configured to transmit the data obtained by the receiving unit 10 directly to the determination mechanism 13. In this case, data relating to the detection area S previously set by the detection area setting mechanism 12 is sent to the determination mechanism 13. The determination mechanism 13 compares the data obtained from the receiving unit 10 with the data relating to the detection area S to determine whether or not the reflected wave is a wave reflected from inside the detection area S.

[0055] The determination mechanism 13 calculates the number of reflected waves from inside the detection area S during measurement as a fulfillment rate relative to the total number of reflected waves from inside the detection area S obtained when there is no obstacle. If this fulfillment rate is equal to or greater than a predetermined threshold, the determination mechanism 13 determines that there is no obstacle and that it is safe, and if the fulfillment rate is less than the threshold, it determines that an obstacle is present.

[0056] In the obstacle detection system 1 of the present invention, it is not essential that the determination mechanism 13 is configured to calculate the sufficiency rate. In this case, the determination mechanism 13 may be configured to determine that there is no obstacle when the number of reflected waves from inside the detection area S is equal to or greater than a predetermined threshold value, such as 50,000 points per unit time, and to determine that there is an obstacle when the number is less than this threshold value.

[0057] The control mechanism 15 is not a mandatory requirement for the obstacle detection system 1 of the present invention. If the moving body 2 is a gantry crane, the determination result by the determination mechanism 13 may be displayed on a display or the like to notify the crane operator. Also, when it is determined that an obstacle is present, an alarm sound or the like may be used to alert the crane operator.

[0058] If the control mechanism 15 is provided, in addition to contacting the crane operator, it is possible to control the automatic deceleration or stopping of the gantry crane. If the gantry crane is an automatic traveling system, the control mechanism 15 may be configured to automatically control the deceleration or stopping.

[0059] The control mechanism 15 may also be configured to control the deceleration rate of the moving body 2 according to the value of the fulfillment rate. For example, the control mechanism 15 may perform control such that the deceleration rate increases as the fulfillment rate decreases. Since the higher the fulfillment rate, the higher the safety state, and the lower the fulfillment rate, the lower the safety state, the moving speed of the moving body 2 decreases when safety is low. When visibility is poor due to heavy rain, the moving speed of the moving body 2 decreases, but the moving body 2 can still travel.

[0060] As illustrated in FIG. 6, the laser light emitted from the transmitter 9 is configured to spread as it moves away from the front side of the moving body 2. Therefore, for example, when the worker 21 is inside the detection area S, the number of reflected waves from inside the detection area S decreases as the worker 21 approaches the moving body 2. The closer the moving body 2 is to the worker 21, the greater the deceleration amount of the moving body 2 can be. In addition, the moving body 2 may be configured to decelerate when the worker 21 is in a position relatively far from the moving body 2 and to stop when the worker 21 is in a position relatively close to the moving body 2. The amount of deceleration may be adjusted according to the number of reflected waves from inside the detection area S, and the control mechanism 15 may be configured to execute control to stop the moving body 2 when the number of reflected waves falls below a predetermined number.

[0061] 3, the obstacle detection system 1 includes an attitude acquisition mechanism 16 that acquires the attitude of a moving body 2, such as a gantry crane, with respect to a traveling surface 8, and a correction mechanism 17 that corrects the position of a detection area S based on a value acquired from the attitude acquisition mechanism 16. In this specification, the attitude of the moving body 2 means the relative inclination of the moving body 2 with respect to the traveling surface 8.

[0062] 7, the attitude acquisition mechanism 16 is configured with an inclination sensor 16a that is installed on the moving body 2 and acquires the inclination of the moving body 2 with respect to the traveling surface 8. Hereinafter, the method of correcting the position of the detection area S using the inclination sensor 16a may be referred to as a first correction.

[0063] In this embodiment, an inclination sensor 16a is provided on each of a pair of leg members 4 opposed to each other with a gap in the moving direction y. A correction mechanism 17 is provided on one of the leg members 4. The positions at which the attitude acquisition mechanism 16 and the correction mechanism 17 are provided are not limited to those described above.

[0064] As shown in Fig. 7, a mobile object 2 such as a gantry crane may tilt around the lateral direction x as a central axis during deceleration. Hereinafter, the tilt around the lateral direction x may be referred to as pitching. When the traveling device 3 is configured with pneumatic rubber tires, pitching occurs when the rubber tires are crushed. When the mobile object 2 is configured with a suspension such as an automobile, pitching also occurs during acceleration and deceleration.

[0065] When the moving object 2 decelerates, the front side in the traveling direction sinks. At this time, the transmitter 9 and other components fixed to the moving object 2 also tilt, which may cause the detection area S to shift downward below the traveling surface 8. In the past, in order to avoid such problems, a trapezoidal detection area S was formed in a side view looking through in the lateral direction x. Because the detection area S was set to be wide, it was difficult to detect a relatively small obstacle that falls inside the detection area S.

[0066] The attitude acquisition mechanism 16 can acquire the pitching angle of the moving body 2. The correction mechanism 17 corrects the position of the detection area S according to this pitching angle. Specifically, the attitude acquisition mechanism 16 acquires an angle -φ1, which is the inclination of the trolley 6 with respect to the traveling surface 8 in the moving direction y. The correction mechanism 17 that acquires this angle -φ1 rotates the detection area S by an angle +φ1, for example, with the lateral direction x as the central axis. When viewed in the lateral direction x, the detection area S is rotated with the corner F1 that is the closest corner of the rectangular detection area S to the transmitting unit 9, etc., as the center. The detection area S is also moved upward. In FIG. 7, the direction in which the detection area S is corrected is indicated by an arrow for the sake of explanation. In reality, the values ​​of the times Tn and Tn' from when the laser light is irradiated from the transmitting unit 9 to when the reflected wave is received by the receiving unit 10 are corrected by the correction mechanism 17.

[0067] Apparently, the detection area S is rotated around the center F1 in a direction that offsets the pitching angle -φ1 of the moving object 2 and is also moved upward. The detection area S is corrected to a position that is substantially the same as the position that is formed on the running surface 8 when no pitching occurs in the moving object 2. The distance by which the detection area S is moved upward is appropriately determined depending on the distance between the pair of leg members 4 opposed to each other with a gap in the moving direction y and the distance from the moving object 2 to the detection area S in the moving direction y.

[0068] The configuration in which the correction mechanism 17 moves the detection area S upward is not an essential requirement. The center for rotating the detection area S may be, for example, the center F2 of the moving body 2 in the moving direction y and the vertical direction z. The detection area S may also be rotated around the center F3 of the moving body 2 in the moving direction y on the running surface 8. When the center of rotation is set outside the detection area S, the position of the detection area S can be corrected to a position along the running surface 8 even if there is no configuration for moving the detection area S upward.

[0069] When the moving body 2 accelerates, pitching occurs in the direction in which the front of the moving body 2 rises up. The attitude acquisition mechanism 16 acquires, for example, the angle +φ1 of the inclination of the trolley 6 with respect to the traveling surface 8. The correction mechanism 17 rotates the detection area S by an angle -φ1 around the lateral direction x as the central axis and moves it downward.

[0070] When multiple detection areas S are set in advance, the multiple detection areas S are corrected collectively. Correcting collectively means correcting the multiple detection areas S based on the same data as if they were a single detection area S with the relative positions of the multiple detection areas S fixed.

[0071] Even if the posture of the moving object 2 is inclined with respect to the traveling surface 8, the position of the detection area S can be corrected to a position along the traveling surface 8. Even if the detection area S is set relatively small in the vertical direction z, a problem does not occur in which the detection area S is located below or above the traveling surface 8. There is no need to set a detection area S that is larger than necessary. Since the detection area S can be set relatively small, even relatively small obstacles can be detected. This is advantageous for improving the accuracy of detecting the presence or absence of an obstacle in the obstacle detection system 1.

[0072] 8, the tilt of the moving body 2 about the central axis in the moving direction y may be obtained by a tilt sensor 16a, and the position of the detection area S may be corrected. In this embodiment, one attitude acquisition mechanism 16 and correction mechanism 17 are provided on the beam member 5. The positions and numbers of the attitude acquisition mechanism 16 and correction mechanism 17 are not limited to those described above.

[0073] When the moving body 2 is configured, for example, as a gantry crane, the moving body 2 may tilt about the moving direction y as its central axis depending on the position of the trolley 6 in the lateral direction x and the weight of the load such as a container suspended by the hoist 7.

[0074] The attitude acquisition mechanism 16 acquires, for example, an angle -φ2 which is the inclination of the beam member 5 with respect to the travel surface 8. The correction mechanism 17 which acquires this angle -φ2 rotates the detection area S by an angle +φ2, for example, around the center F4 of the moving body 2 in the lateral direction x on the travel surface 8. At this time, a pair of detection areas S formed with an interval in the lateral direction x are corrected collectively.

[0075] It is preferable that the correction mechanism 17 is configured to perform both the first correction of rotating the detection area S about the lateral direction x as a central axis as illustrated in Fig. 7, and the first correction of rotating the detection area S about the moving direction y as a central axis as illustrated in Fig. 8. In this case, for example, the obstacle detection system 1 may be configured to perform the first correction about the lateral direction x and the moving direction y as central axes by using two tilt sensors 16a respectively installed at two points diagonally positioned on the moving body 2 in a plan view and one correction mechanism 17 connected to the tilt sensors 16a.

[0076] The obstacle detection system 1 may be configured to perform only one of the first correction with the lateral direction x as the central axis or the first correction with the moving direction y as the central axis. In the case where the moving body 2 is unlikely to tilt with the moving direction y as the central axis, such as an automobile, the obstacle detection system 1 may be configured to perform only the first correction with the lateral direction x as the central axis.

[0077] The inclination sensor 16a may be installed at a position relatively close to the running surface 8, such as on the traveling device 3, and at a position relatively far from the running surface 8, such as on the beam member 5, and the inclination of the moving body 2 with respect to the running surface 8 may be obtained from the difference between the angles obtained by these two inclination sensors 16a. The inclination sensor 16a installed at a position close to the running surface 8 may be installed on a dolly that is towed by the moving body 2 and runs while touching the running surface 8. The inclination sensor 16a installed on the dolly can obtain the inclination of the running surface 8 with relatively high accuracy without being affected by pitching, etc. of the moving body 2. The inclination sensor 16a installed at a position far from the running surface 8 may be installed near the transmitter 9, etc.

[0078] The tilt sensor 16a constituting the attitude acquisition mechanism 16 may be configured to measure the amount of change in the tilt of the moving body 2. When the traveling surface 8 is inclined and the attitude of the moving body 2 is inclined due to this inclination, the tilt sensor 16a continues to detect a constant tilt with respect to the horizontal. Since the amount of change in the tilt of the moving body 2 becomes zero, the detection sensor outputs that the tilt of the moving body 2 with respect to the traveling surface 8 is zero degrees. When the tilt detected by the tilt sensor 16a changes due to acceleration / deceleration of the moving body 2, etc., the tilt sensor 16a outputs the amount of change as the tilt of the moving body 2 with respect to the traveling surface 8.

[0079] 9, the attitude acquisition mechanism 16 may be composed of a storage unit 16b in which map information combining inclination information of the traveling surface 8 and position coordinates is stored in advance, and a position information acquisition unit 16c that acquires the position of the moving body 2. Hereinafter, the method of correcting the position of the detection area S by using the map information may be referred to as a second correction.

[0080] In this embodiment, the memory unit 16b is installed on a leg member 4 of the gantry crane. The location where the memory unit 16b is installed is not limited to this. The memory unit 16b may be incorporated into a management system that is installed in a management building of a container terminal and manages the operation of the gantry crane and the like. In other words, the memory unit 16b may be installed in a location away from the mobile body 2. In this case, the mobile body 2 and the memory unit 16b are equipped with wireless communication devices and the like that can send and receive data to and from each other.

[0081] The position information acquisition unit 16c is configured, for example, by a Global Navigation Satellite System (GNSS) antenna. Methods for measuring position coordinates using a GNSS antenna include point positioning, relative positioning, DGPS (Differential GPS) positioning, and RTK (Real Time Kinematic GPS) positioning. The position information acquisition unit 16c is not limited to GNSS, and the mobile object 2 may have a configuration capable of acquiring its own position. In the case where the mobile object 2 is configured as a gantry crane, the position information acquisition unit 16c may have a configuration for acquiring the position of the mobile object 2 by utilizing the relative position with respect to a plurality of transponders installed in a container terminal.

[0082] The attitude acquisition mechanism 16 first acquires the position coordinates of the moving body 2 by the position information acquisition unit 16c. For example, the position coordinates of each point of the container terminal and the inclination of the running surface 8 on the forward side in the moving direction y of the moving body 2 at the position coordinates are prepared in advance as map information and stored in the storage unit 16b. Specifically, as illustrated in Fig. 9, the map information stored in the storage unit 16b shows that, for example, the inclination of the running surface 8 is 0° in the range of 0-3 m toward the front of the moving body 2 and the inclination of the running surface 8 is +3° in the range of 3-15 m.

[0083] The correction mechanism 17 acquires map information corresponding to the position coordinates of the moving body 2 from the attitude acquisition mechanism 16. The correction mechanism 17 first divides the detection area S at the boundary where the inclination of the travel surface 8 changes in the moving direction y. In this embodiment, the detection area S is divided into a first detection area S1 and a second detection area S2 at a position 3 m ahead of the moving body 2. The correction mechanism 17 corrects the position of the detection area S with a different value for each divided detection area S. When the inclination of the travel surface 8 in the first detection area S1 is ±0°, the correction mechanism 17 performs correction based on the inclination ±0°. In this case, the position of the first detection area S1 is the same as without correction and does not change. When the inclination of the travel surface in the second detection area S2 is +3°, the correction mechanism 17 performs correction based on the inclination +3°. In this case, the second detection area S2 is corrected to a position rotated by +3° around the preset correction center F5. The correction center F5 is set to the corner of the rectangular second detection area S2 that is closest to the transmitter 9, etc., when viewed in the lateral direction x, for example. The correction center F5 can be set appropriately, for example, outside or inside the detection area S.

[0084] The obstacle detection system 1 is capable of correcting the position of the detection area S according to the attitude of the moving object 2 with respect to the traveling surface 8. Here, the attitude of the moving object 2 refers to the relative inclination of the moving object 2 with respect to the traveling surface 8 located directly below the current position of the moving object 2 and with respect to the traveling surface 8 located ahead of the moving object 2 in the traveling direction.

[0085] The position of the boundary between the first detection area S1 and the second detection area S2 changes in accordance with the movement of the moving object 2. The position of the boundary between the first detection area S1 and the second detection area S2 may be configured to be updated sequentially at a predetermined time interval, such as every five seconds, in accordance with the movement of the moving object 2.

[0086] It is possible to set the detection area S in a state that follows the change in the inclination of the traveling surface 8. This is advantageous in improving the accuracy with which the obstacle detection system 1 detects the presence or absence of an obstacle.

[0087] A configuration in which the correction mechanism 17 divides the detection area S based on map information is not an essential requirement of the correction mechanism 17. A configuration in which multiple detection areas S are set in advance may be used, as exemplified in Fig. 10. In this case, the position of each detection area S is adjusted according to the map information. Correcting each of the multiple detection areas S means that each detection area S is independently corrected based on different data.

[0088] In this embodiment, the boundaries of each detection area S are fixed without changing their positions. In addition to being rotatable about the central axis of the lateral direction x and the moving direction y, the detection area S may be configured to be three-dimensionally adjusted in the vertical direction z, the lateral direction x, and the moving direction y.

[0089] The map information may include the inclination of the traveling surface 8 with the moving direction y as the central axis. As illustrated in Fig. 11, one traveling unit 3 (left side in Fig. 11) of a gantry crane constituting the mobile body 2 may travel on a traveling surface 8 with an inclination of ±0°, while the other traveling unit 3 (right side in Fig. 11) may travel on a traveling surface 8 with an inclination of +1°. In such a case, the obstacle detection system 1 becomes able to correct the position of the detection area S. The position of the detection area S1-3 is corrected by the correction mechanism 17 to a position along the traveling surface 8.

[0090] When there is no obstacle, the laser light or the like emitted from the transmitter 9 is reflected by the surface of the traveling surface 8. The obstacle detection system 1 may have a configuration for updating the inclination information of the traveling surface 8 based on this reflected wave. For example, a gantry crane performs loading and unloading work while going back and forth on the traveling surface 8 within a predetermined range multiple times a day. The obstacle detection system 1 can detect the surface of the traveling surface 8 based on the information of the distance to the reflection point Pn. The position of the surface of the traveling surface 8 is detected for each position coordinate of the gantry crane. The position of the surface of the traveling surface 8 obtained multiple times may be averaged to obtain the inclination information of the traveling surface 8 at the predetermined coordinate, and the map information may be updated. Fine adjustment of the map information is repeated as the moving body 2 moves. Even if the inclination of the traveling surface 8 changes due to aging, it is possible to correct the position of the detection area S in a state that follows this change. The obstacle detection system 1 excludes data when it determines that there is an obstacle from the data used to update the map information. The obstacle detection system 1 may be configured to separately survey the traveling surface 8 and update the map information based on the results.

[0091] The obstacle detection system 1 may be configured to perform a combination of the first correction using the tilt sensor 16a and the second correction using map information. The obstacle detection system 1 first performs the second correction to correct the detection area S based on the map information. If the moving body 2 is then inclined relative to the traveling surface 8 due to acceleration / deceleration of the moving body 2 or movement of the trolley 6, the first correction is performed.

[0092] When performing the first correction, the relative inclination of the moving object 2 with respect to the traveling surface 8 may be obtained from the value of the inclination sensor 16a and the inclination information obtained from the map information. For example, if the value of the inclination sensor 16a is +6° and the inclination obtained from the map information is +2°, the relative inclination of the moving object 2 with respect to the traveling surface 8 is +4°. The inclination obtained from the map information is the inclination of the traveling surface 8 directly below the moving object 2. The obstacle detection system 1 may be configured to perform the first correction based on this relative inclination.

[0093] The obstacle detection system 1 may be configured to perform at least one of the first correction and the second correction. When the moving body 2 is a stacker crane used in a warehouse or the like where the traveling surface 8 has almost no inclination, the obstacle detection system 1 may be configured to perform only the first correction. In this case, the attitude acquisition mechanism 16 is configured only with the inclination sensor 16a. When the moving body 2 is a vehicle or the like whose inclination hardly changes in the front-back and left-right directions, the obstacle detection system 1 may be configured to perform only the second correction. In this case, the attitude acquisition mechanism 16 is configured with a memory unit 16b and a position information acquisition unit 16c.

[0094] After the determination mechanism 13 determines that there is an obstacle, the determination mechanism 13 may be configured to perform a second determination to determine again whether or not there is an obstacle, based on the reflected wave reflected outside the detection area S. Specifically, the determination mechanism 13 can perform the second determination, for example, based on the intensity of the reflected wave. When performing the second determination, the determination mechanism 13 obtains data on the reflected wave reflected outside the detection area S from the receiving unit 10 or the comparison mechanism 11.

[0095] If the obstacle is, for example, a container or a chassis, the laser light is reflected outside the detection area S. Since the receiver 10 does not receive reflected waves from inside the detection area S, the determination mechanism 13 determines that an obstacle is present. The determination mechanism 13 then performs a second determination. Since containers and the like tend to reflect laser light, the intensity of the reflected waves becomes relatively large. The determination mechanism 13 can determine the size and position of the obstacle from the reflection points Pn of the multiple reflected waves. The determination mechanism 13 also determines that an obstacle is present in the second determination.

[0096] If the obstacle is, for example, a puddle formed on the driving surface 8, the strength of the reflected wave may be low or no reflected wave may be obtained due to diffuse reflection or absorption. Since the receiver 10 does not obtain a predetermined number of reflected waves from inside the detection area S, the determination mechanism 13 determines that an obstacle is present. The determination mechanism 13 then performs a second determination. In the second determination, the determination mechanism 13 attempts to refer to data on reflected waves reflected outside the detection area S.

[0097] If the laser light is absorbed by a puddle, the receiver 10 will not obtain any reflected wave. There will be no data on the reflected wave from outside the detection area S. If no obstacle is anticipated that would absorb the laser light and prevent reflected light from being obtained, the determination mechanism 13 may be configured to determine in the second determination that no obstacle is present. If it is determined in the second determination that no obstacle is present, the moving body 2 continues moving.

[0098] There are cases where the laser light is diffusely reflected by a puddle, and some of the multiple laser light beams are received by the receiving unit 10 with weak intensity. There are also cases where reflected waves are partially obtained from inside the detection area S. In such cases, it may be determined that there is a puddle, and the determination mechanism 13 may determine that there is no obstacle in the second determination. If there is no obstacle in the second determination, the moving body 2 continues moving. [Explanation of symbols]

[0099] 1 Obstacle Detection System 2. Mobile 3 Running gear 4 Leg members 5 Beam members 6 Trolley 7 Hanging equipment 8 Running surface 9. Transmission Section 10 Receiving section 11 Comparison mechanism 12 Detection area setting mechanism 13 Judgment mechanism 14 Threshold setting mechanism 15 Control Mechanism 16 Attitude acquisition mechanism 16a Inclination sensor 16b Storage section 16c Location information acquisition section 17 Correction mechanism 18 Reference Line 19a Long side (upper side) 19b Long side (bottom) 20a Short side (front) 20b Short side (rear) 21 Worker θn (laser light) angle Pn reflection point S Detection area φ (of moving object) inclination Fn (correction) center S1 First detection area S2 Second detection area x transverse direction y movement direction z Vertical direction

Claims

1. In an obstacle detection method, at least one detection area is set in advance in a peripheral area of ​​a reflection point where an electromagnetic wave is reflected when there is no obstacle, an electromagnetic wave is emitted from a transmitter installed in a moving object toward the detection area while changing an irradiation angle, a reflected wave of the electromagnetic wave is received by a receiver, and a determination mechanism determines the presence or absence of an obstacle according to the reflected wave reflected inside the detection area, correcting the position of the detection area in accordance with the attitude of the moving body with respect to a traveling surface on which the moving body travels; After the determination mechanism determines that an obstacle is present, The obstacle detection method is characterized in that the determination mechanism is configured to perform a second determination to determine again the presence or absence of an obstacle based on the reflected wave reflected outside the detection area.

2. In an obstacle detection method, at least one detection area is set in advance in a peripheral area of ​​a reflection point where an electromagnetic wave is reflected when there is no obstacle, an electromagnetic wave is emitted from a transmitter installed in a moving object toward the detection area while changing an irradiation angle, a reflected wave of the electromagnetic wave is received by a receiver, and a determination mechanism determines the presence or absence of an obstacle according to the reflected wave reflected inside the detection area, correcting the position of the detection area in accordance with the attitude of the moving body with respect to a traveling surface on which the moving body travels; After the determination mechanism determines that an obstacle is present, The obstacle detection method is characterized in that the determination mechanism is configured to perform a second determination to determine again the presence or absence of an obstacle depending on the intensity of the reflected wave.

3. 3. The obstacle detection method according to claim 1, further comprising the step of acquiring an inclination of the moving body relative to a surface on which the moving body is traveling, and performing a first correction for correcting the position of the detection area based on the inclination.

4. The obstacle detection method according to claim 3 , wherein the first correction comprises a configuration in which the positions of the plurality of detection areas are collectively corrected based on an inclination of the moving object.

5. An obstacle detection method according to any one of claims 1 to 4, wherein map information combining inclination information of the traveling surface and position coordinates is prepared in advance, and a second correction is performed to correct the position of the detection area based on the inclination information corresponding to the position coordinates of the moving body.

6. The obstacle detection method according to claim 5 , wherein the second correction comprises dividing the detection area into a plurality of areas based on a value obtained from the map information.

7. 7. The obstacle detection method according to claim 5, wherein the second correction is configured to correct each of the plurality of detection areas based on a value obtained from the map information.

8. An obstacle detection system comprising: a transmitter that is installed on a moving body and that emits electromagnetic waves while changing an irradiation angle; a receiver that receives reflected waves of the electromagnetic waves; a detection area setting mechanism that presets at least one detection area in a peripheral area of ​​a reflection point where the electromagnetic waves are reflected when there is no obstacle; and a determination mechanism that determines the presence or absence of an obstacle based on the reflected waves reflected inside the detection area, a posture acquisition mechanism that acquires a posture of the moving body with respect to a traveling surface on which the moving body travels, and a correction mechanism that corrects a position of the detection area based on a value acquired from the posture acquisition mechanism, The obstacle detection system is characterized in that the judgment mechanism is configured to, after determining that an obstacle is present, perform a second judgment to determine the presence or absence of an obstacle again based on the reflected wave reflected outside the detection area.

9. An obstacle detection system comprising: a transmitter that is installed on a moving body and that emits electromagnetic waves while changing an irradiation angle; a receiver that receives reflected waves of the electromagnetic waves; a detection area setting mechanism that presets at least one detection area in a peripheral area of ​​a reflection point where the electromagnetic waves are reflected when there is no obstacle; and a determination mechanism that determines the presence or absence of an obstacle based on the reflected waves reflected inside the detection area, a posture acquisition mechanism that acquires a posture of the moving body with respect to a traveling surface on which the moving body travels, and a correction mechanism that corrects a position of the detection area based on a value acquired from the posture acquisition mechanism, The obstacle detection system is characterized in that the judgment mechanism is configured to perform a second judgment to determine the presence or absence of an obstacle again based on the intensity of the reflected wave after determining that an obstacle is present.

10. the attitude acquisition mechanism has an inclination sensor that is installed on the moving body and acquires an inclination of the moving body with respect to a running surface on which the moving body runs, 10. The obstacle detection system according to claim 8, wherein the correction mechanism is configured to correct the position of the detection area based on a value obtained from the tilt sensor.

11. the attitude acquisition mechanism includes a storage unit in which map information combining inclination information of the travel surface and position coordinates is stored in advance, and a position information acquisition unit that acquires a position of the moving body, 11. The obstacle detection system according to claim 8, wherein the correction mechanism is configured to correct the position of the detection area based on a value obtained from the map information.

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