Vehicle and obstacle detection method

Abstract

To provide a vehicle and an obstacle detection method capable of quickly and accurately detecting an obstacle that hinders travel.SOLUTION: In an unmanned guided vehicle 1, an entry area Sa is provided for each traveling mode based on a position at which a vehicle body 2 enters, and obstacles within the entry area Sa corresponding to the traveling mode are detected from the conditions around the entire circumference of the vehicle body 2 acquired from obstacle sensors 4f, 4b. The entry area Sa is an area based on the traveling mode, and is therefore an area into which the unmanned guided vehicle 1 actually enters, regardless of an environment in which the unmanned guided vehicle 1 travels. By detecting obstacles present within such an entry area Sa, the unmanned guided vehicle 1 can quickly and accurately detect obstacles that hinder its travel.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a vehicle and an obstacle detection method. [Background technology]

[0002] Patent Document 1 discloses an automated guided vehicle 10 that travels while detecting surrounding objects using safety laser scanners 18 and 19. Specifically, the automated guided vehicle 10 sets a predetermined range in a direction in which no walls exist on the route R along which the automated guided vehicle 10 travels as a detection range for detecting objects, based on scan information from the safety laser scanners 18 and 19. This makes it possible to limit the detection range compared to when an object is detected from the entire range of the scan information detected by the safety laser scanners 18 and 19, so that an object located in the traveling direction of the automated guided vehicle 10 can be quickly detected. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-59317 A (e.g., paragraphs 0056-0063, FIG. 18) Summary of the Invention [Problem to be solved by the invention]

[0004] However, when there is no wall on the route R or when a wall is installed on only one of the left and right sides of the route R, there are many directions in which there are no walls, and the detection range is also wide. This causes a problem that it takes time to detect an object within the detection range, or an object unrelated to the traveling direction of the automatic guided vehicle 10 is detected within the detection range, so that the automatic guided vehicle 10 may not be able to quickly and accurately detect an object that hinders its travel.

[0005] The present invention has been made to solve the above-mentioned problems, and has an object to provide a vehicle and an obstacle detection method that can quickly and accurately detect obstacles that hinder driving. [Means for solving the problem]

[0006] In order to achieve this object, the vehicle of the present invention comprises a vehicle body, a detection means for detecting the conditions around the vehicle body, and an obstacle detection means for detecting obstacles from the detection results of the detection means, as well as a driving mode acquisition means for acquiring a driving mode of the vehicle, and an area acquisition means for acquiring an entry area around the vehicle body which is an area into which the vehicle body will enter when driving in the driving mode acquired by the driving mode acquisition means, and the obstacle detection means detects obstacles present within the entry area acquired by the area acquisition means in the detection results of the detection means.

[0007] The obstacle detection method of the present invention is a method comprising a detection step of detecting the situation around the vehicle body of a vehicle, and an obstacle detection step of detecting an obstacle from the detection result of the detection step, and further comprising a driving mode acquisition step of acquiring a driving mode of the vehicle, and an area acquisition step of acquiring an entry area around the vehicle body, which is an area into which the vehicle body will enter when driving in the driving mode acquired in the driving mode acquisition step, and the obstacle detection step detects an obstacle present within the entry area acquired in the area acquisition step in the detection result of the detection step. Effect of the Invention

[0008] According to the vehicle of claim 1, the vehicle's driving mode is acquired, and an entry area into which the vehicle body enters according to the acquired driving mode is acquired around the vehicle body. Then, an obstacle present in the acquired entry area is detected in the detection result of the surrounding situation of the vehicle body detected by the detection means. Since the entry area is an area acquired based on the driving mode, an area into which the vehicle actually enters is acquired regardless of the environment in which the vehicle travels. By detecting an obstacle present in such an entry area, there is an effect that an obstacle that impedes the travel of the vehicle can be quickly and accurately detected.

[0009] In addition, since the entry area is an area based on the driving mode, the entry area can include not only an area based on the current traveling direction of the vehicle, but also an area into which the vehicle will enter in the future if the traveling direction changes midway, such as when turning right or left. Detecting obstacles present in such an entry area also has the effect of accurately detecting obstacles that may impede the traveling of the vehicle.

[0010] According to the vehicle described in claim 2, in addition to the effect of the vehicle described in claim 1, the traveling speed of the vehicle is acquired, and the stopping distance, which is the distance the vehicle will stop if it is stopped from that traveling speed, is acquired, and if there is an obstacle within the stopping distance among the detected obstacles, the traveling of the vehicle is stopped. This has the effect of reliably avoiding a situation in which the traveling vehicle comes into contact with an obstacle in the entry area.

[0011] According to the vehicle of claim 3, in addition to the effect of the vehicle of claim 1, the size of the area in the travel direction side of the entry area is changed according to the traveling speed of the vehicle. That is, by making the size of the entry area in the travel direction side according to the traveling speed, it is possible to prevent the entry area from being too small or too large for the traveling speed, and therefore it is possible to prevent the obstacle from being overdetected or the obstacle from being overdetected.

[0012] According to the vehicle of claim 4, in addition to the effect of the vehicle of claim 3, the faster the travel speed of the transport vehicle, the larger the area on the travel direction side of the entry area is expanded in the travel direction. Since the faster the travel speed of the vehicle, the longer the distance the vehicle travels in the travel direction per unit time, by expanding the travel direction side of the entry area in the travel direction as the travel speed is higher, there is an effect that obstacles that the vehicle may come into contact with due to its travel can be detected more accurately.

[0013] According to the vehicle of claim 5, in addition to the effect of the vehicle of claim 1, the size of the area on the vehicle turning center side in the approach area is changed according to the turning radius. That is, by making the turning center side of the approach area a size according to the turning radius, it is possible to prevent the approach area from being too small or too large with respect to the turning of the vehicle, and therefore it is possible to prevent the obstacle from being overdetected or the obstacle from being detected excessively.

[0014] According to the vehicle of claim 6, in addition to the effect of the vehicle of claim 5, the smaller the turning radius, the larger the area on the turning center side is expanded toward the turning center. The smaller the turning radius of the vehicle, i.e., the closer the turning center is to the vehicle, the more maneuverable the vehicle is, and the wider the area that the vehicle enters toward the turning center side per unit time becomes. Therefore, by expanding the turning center side of the entry area toward the turning center more toward the turning center as the turning radius of the vehicle is smaller, there is an effect that obstacles that may come into contact with due to the vehicle's tight turning can be detected more accurately.

[0015] According to the obstacle detection method recited in claim 7, the same effects as those of the vehicle recited in claim 1 are achieved. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1(a) is a side view of an automatic guided vehicle according to one embodiment of the present invention, and FIG. 1(b) is a top view of the automatic guided vehicle as seen from the direction of the arrow Ib in FIG. 1(a). [Diagram 2](a) is a diagram showing the entry area when the driving mode is straight ahead, (b) is a diagram showing the entry area when the driving mode is right lateral travel, (c) is a diagram showing the entry area when the driving mode is right diagonal travel, (d) is a diagram showing the entry area when the driving mode is right turn, (e) is a diagram showing the entry area when the driving mode is right turn, and (f) is a diagram showing the entry area when the driving mode is rotation. [Diagram 3] FIG. 2A is a block diagram showing the electrical configuration of an automatic guided vehicle, and FIG. 2B is a diagram showing a schematic representation of approach area data. [Figure 4] 13 is a flowchart showing a main process. [Diagram 5] 1A is a diagram showing the entry area when the driving mode in the modified example is straight ahead, FIG. 1B is a diagram showing the entry area when the driving mode in the modified example is straight ahead and the driving speed is faster than that in (a), FIG. 1C is a diagram showing the entry area when the driving mode in the modified example is a right turn, and FIG. 1D is a diagram showing the entry area when the driving mode in the modified example is a right turn and the turning radius is smaller than that in (c). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] A preferred embodiment of the present invention will be described below with reference to the accompanying drawings. First, the configuration of an automated guided vehicle 1 in this embodiment will be described with reference to Fig. 1. Fig. 1(a) is a side view of the automated guided vehicle 1 in one embodiment of the present invention, and Fig. 1(b) is a top view of the automated guided vehicle 1 as viewed from the direction of arrow Ib in Fig. 1(a). The direction of arrow F in Fig. 1 indicates the forward direction of the automated guided vehicle 1.

[0018] The automated guided vehicle 1 is a vehicle that carries an object (not shown) and travels on it, and includes a rectangular vehicle body 2 when viewed from above, traveling devices 3, a front obstacle sensor 4f, and a rear obstacle sensor 4b. Other configurations of the automated guided vehicle 1 are known, so a description thereof will be omitted. The traveling devices 3 are devices that cause the automated guided vehicle 1 to travel, and are disposed below the vehicle body 2, at each of the four corners of the automated guided vehicle 1 when viewed from above. Each traveling device 3 is provided with an axle 3a, a pair of wheels 3b disposed at both ends of the axle 3a, and a rotating shaft 3c that connects the axle 3a and the vehicle body 2 so as to be freely steerable around a vertical axis of the vehicle body 2.

[0019] The traveling device 3 is further provided with a rotation drive device 3d that rotates the wheels 3b and a steering drive device 3e that steers the rotation shaft 3c (see FIG. 3 for both). A steering angle for traveling when the automated guided vehicle 1 transports an object is calculated for each traveling device 3, and the steering drive device 3e steers the rotation shaft 3c so that the wheels 3b face the calculated steering angle.

[0020] In this embodiment, the automated guided vehicle 1 travels according to a travel mode, such as going straight or traversing to the right, instructed by a host process controller (not shown) that manages the travel of the automated guided vehicle 1. In the automated guided vehicle 1, the rotation drive device 3d and the steering drive device 3e are controlled so that the automated guided vehicle 1 travels according to the instructed travel mode. Details of the travel modes will be described later with reference to FIG. 2.

[0021] The front obstacle sensor 4f is a sensor that mainly detects objects (obstacles) located in front and to the right of the vehicle body 2 (upper and right sides of the paper in FIG. 1(b)), and is provided at the right end of the front part of the vehicle body 2. The rear obstacle sensor 4b is a sensor that mainly detects objects (obstacles) located in the rear and to the left of the vehicle body 2 (left and lower sides of the paper in FIG. 1(b)), and is provided at the left end of the rear part of the vehicle body 2.

[0022] The front obstacle sensor 4f and the rear obstacle sensor 4b are each configured to be able to obtain the situation within a 270-degree range in the horizontal direction, specifically, the presence or absence of an object. Since the vehicle body 2 in this embodiment is formed in a rectangular shape, the situation around the entire circumference of the vehicle body 2 can be obtained by only two sensors, the front obstacle sensor 4f provided at the right end of the front part of the vehicle body 2 and the rear obstacle sensor 4b provided at the left end of the rear part of the vehicle body 2. In other words, since the situation around the entire circumference of the vehicle body 2 can be obtained without providing a large number of sensors on the vehicle body 2, the manufacturing cost of the automatic guided vehicle 1 can be reduced.

[0023] In this embodiment, the front obstacle sensor 4f and the rear obstacle sensor 4b are configured with LiDAR (Laser Imaging Detection And Ranging). The front obstacle sensor 4f and the rear obstacle sensor 4b are not limited to being configured with LiDAR, and may be, for example, an infrared sensor or a CMOS camera that can detect the surrounding situation. Hereinafter, when there is no need to distinguish between the front obstacle sensor 4f and the rear obstacle sensor 4b, they will be abbreviated as "obstacle sensors 4f, 4b".

[0024] From the surrounding conditions detected by these obstacle sensors 4f, 4b, an obstacle that may hinder the travel of the automated guided vehicle 1 is detected, and when the distance between the automated guided vehicle 1 and the obstacle becomes equal to or less than a predetermined stopping distance, the automated guided vehicle 1 stops traveling. Here, the obstacle sensors 4f, 4b acquire the conditions of the entire circumference of the vehicle body 2, so it takes time to detect an obstacle from the acquired conditions of the entire circumference of the vehicle body 2. On the other hand, the area that the automated guided vehicle 1 enters during its travel is limited among the entire circumference of the vehicle body 2, so if an obstacle is detected from the entire circumference of the vehicle body 2, an object that exists in a position unrelated to the travel of the automated guided vehicle 1 will also be erroneously detected as an obstacle that may hinder the travel, and the automated guided vehicle 1 will stop unnecessarily.

[0025] Therefore, in this embodiment, an entry area Sa based on the travel mode of the automatic guided vehicle 1 is acquired, and an obstacle is detected from an area corresponding to the entry area Sa among the conditions of the entire circumference of the vehicle body 2 acquired by the obstacle sensors 4f, 4b, thereby quickly and accurately detecting an obstacle that hinders the travel of the automatic guided vehicle 1. Here, the travel mode of the automatic guided vehicle 1 and the entry area for each travel mode will be described with reference to Fig. 2.

[0026] Figure 2(a) is a diagram showing an entry area Sa1 when the driving mode is straight ahead, Figure 2(b) is a diagram showing an entry area Sa2 when the driving mode is right lateral travel, Figure 2(c) is a diagram showing an entry area Sa3 when the driving mode is right diagonal travel, Figure 2(d) is a diagram showing an entry area Sa4 when the driving mode is right turn, Figure 2(e) is a diagram showing an entry area Sa5 when the driving mode is right turn, and Figure 2(f) is a diagram showing an entry area Sa6 when the driving mode is rotation.

[0027] In this embodiment, the driving modes of the unmanned guided vehicle 1 mainly include straight ahead travel (FIG. 2(a)), where the unmanned guided vehicle 1 travels straight ahead to the right (FIG. 2(b)), right lateral travel (FIG. 2(c)), where the unmanned guided vehicle 1 travels straight ahead diagonally to the right (FIG. 2(c)), right turn (FIG. 2(d)), where the unmanned guided vehicle 1 that has been travelling straight ahead changes direction to the right (FIG. 2(d)), right turn (FIG. 2(e)), and rotation (FIG. 2(f)), where the unmanned guided vehicle 1 rotates on the spot.

[0028] In addition to the above, other driving modes include reverse, in which the unmanned guided vehicle 1 travels straight backward, left diagonal, in which the unmanned guided vehicle 1 travels straight diagonally forward to the left, left turn, in which the unmanned guided vehicle 1 changes direction to the left, and left turn, in which the unmanned guided vehicle 1 turns to the left. However, since all of these modes have different directions of travel from the above-mentioned straight ahead, right lateral travel, right diagonal travel, right turn, and right turn, detailed explanations of these will be omitted.

[0029] The upper process controller transmits to the unmanned guided vehicle 1 a driving mode for moving the unmanned guided vehicle 1 to a predetermined position (e.g., a position for loading and unloading transported goods), and the unmanned guided vehicle 1 controls the rotation drive device 3d and the steering drive device 3e so that the unmanned guided vehicle 1 travels according to the received driving mode.

[0030] An entry area Sa is provided for each travel mode. In this embodiment, the entry area Sa is an area that is set based on the position into which the vehicle body 2 of the automatic guided vehicle 1 enters when the automatic guided vehicle 1 travels at a medium travel speed (e.g., 0.5 m / s) in the set travel mode. In other words, the entry area Sa is an area that is outside the vehicle body 2 at that time, but into which the vehicle body 2 enters when traveling in the set travel mode. The entry area Sa for each travel mode will be described with reference to Figs. 2(a) to (f).

[0031] First, referring to Fig. 2(a), the entry area Sa1, which is the entry area Sa when the driving mode is straight ahead, will be described. When the driving mode is straight ahead, the automatic guided vehicle 1 travels forward, so the entry area Sa1 in this case is set on the front side of the vehicle body 2. Since the vehicle body 2 is formed in a rectangular shape when viewed from above, the entry area Sa1 into which the vehicle body 2 enters by going straight ahead is also rectangular.

[0032] Specifically, the entry area Sa1 is formed by an area surrounded by an extension of the right end of the vehicle body 2, an extension of the left end of the vehicle body 2, the front end of the vehicle body 2, and a line segment obtained by offsetting the front end of the vehicle body 2 forward. The offset amount may be equal to or greater than the distance traveled from when the automated guided vehicle 1 starts braking until it stops (i.e., the stopping distance). The larger the offset amount, the larger the area of ​​the entry area Sa1 becomes, ensuring the safety of the automated guided vehicle 1. However, at the same time, it takes longer to detect an obstacle in the entry area Sa1 in the processes of S6 to S9 described later in FIG. 4, and there is a greater concern that an obstacle may be erroneously detected.

[0033] Therefore, in this embodiment, if the stopping distance when the automatic guided vehicle 1 travels at a medium travel speed (0.5 m / s) is set to "2 m", the offset amount is set to "3 m" which is longer than the stopping distance. The offset amount is not limited to "3 m" as long as it is longer than the stopping distance, and may be, for example, "2 m" or "2.5 m". On the other hand, when the travel mode is straight ahead, the vehicle body 2 does not enter the rear, left, and right sides, so that the entry area Sa1 is not set on the rear, left, and right sides of the vehicle body 2.

[0034] 2(b), the approach area Sa2, which is the approach area Sa when the driving mode is right-lateral travel, will be described. When the driving mode is right-lateral travel, the traveling direction of the automated guided vehicle 1 is to the right, so the approach area Sa2 in this case is set to the right of the vehicle body 2. Like the approach area Sa1 described above, the approach area Sa2 is also formed in a rectangular shape.

[0035] Specifically, the entry area Sa2 is configured as an area surrounded by an extension line of the front end of the vehicle body 2, an extension line of the rear end of the vehicle body 2, the right end of the vehicle body 2, and a line segment obtained by offsetting the right end of the vehicle body 2 to the right. Note that the offset amount is the same as in the case of going straight ahead described above, and therefore a description thereof will be omitted. Also, the offset amount in the travel mode described below is similar, and therefore a description thereof will be omitted. When the travel mode is right lateral travel, the vehicle body 2 does not enter the front, rear, or left side of the vehicle body 2, and therefore the entry area Sa2 is not set on the front, rear, or left side of the vehicle body 2.

[0036] 2(c), the approach area Sa3, which is the approach area Sa when the travel mode is right oblique travel, will be described. When the travel mode is right oblique travel, the traveling direction of the automatic guided vehicle 1 is right obliquely forward, so that the approach area Sa3 in this case is set on the front and right sides of the vehicle body 2. The approach area Sa3 is shaped to follow the movement of the vehicle body 2 diagonally forward to the right.

[0037] Specifically, the entry area Sa3 is composed of the area surrounded by line segments R1P1, P1P2, P2P3, P3R3, R3R2, and R2R1, when the vehicle body 2 is traveling forward at an angle of 45° diagonal to the right in the fore-and-aft direction, and includes the corner R1 at the front left end of the vehicle body 2, a point P1 offset from that corner R1 at an angle of 45° diagonal to the right, the corner R2 at the front right end of the vehicle body 2, a point P2 offset from that corner R2 at an angle of 45° diagonal to the right, and the corner R3 at the rear right end of the vehicle body 2, and a point P3 offset from that corner R3 at an angle of 45° diagonal to the right.

[0038] 2(d), an entry area Sa4 that is the entry area Sa when the driving mode is a right turn will be described. When the driving mode is a right turn, the automatic guided vehicle 1 moves forward while turning rightward, so that the entry area Sa4 in this case is set on the front and right sides of the vehicle body 2. The entry area Sa4 is shaped to follow the movement of the vehicle body 2 diagonally forward to the right.

[0039] Specifically, the approach area Sa4 is composed of an area surrounded by the arc C1, the normal line N1, the arc C2, and the front end and right end of the vehicle body 2. The arc C1 is an arc that starts at the angle R1 and is drawn with a turning radius centered on the turning center. The length of the arc C1 is set to a length substantially equal to the offset amount. Here, the turning center is a position that is set when the automated guided vehicle 1 turns right and turns right, which will be described later. A virtual arc is created that passes through the center of the axle 3a (which coincides with the center of the rotation shaft 3c in this embodiment) centered on the turning center, and the steering drive device 3e is controlled to follow the created arc when turning right and turning right, thereby realizing a change in direction of the automated guided vehicle 1 to the right.

[0040] The normal line N1 is a normal line extending from an end point E1 opposite to the corner R1 on the arc C1. The length of the normal line N1, i.e., the distance from the end point E1 to an end point E2 opposite to the end point E1 on the normal line N1, is set to a length substantially equal to the vehicle width of the vehicle body 2. The arc C2 is an arc drawn with a turning radius starting from the corner R3 and centered on the turning center, and is an arc connecting the corner R3 and the end point E2 on the normal line N1.

[0041] The length of the arc C1 is not limited to a length based on the offset amount, and may be longer than the offset amount. The length of the normal line N2 is not limited to a length based on the vehicle width of the vehicle body 2, and may be longer than the vehicle width. Equations for calculating the lengths of the arcs C1, C2, and the normal line N1 may be prepared in advance, and the lengths of the arcs C1, C2, and the normal line N1 may be calculated from the equations.

[0042] Unlike the case of right oblique travel in which the vehicle continues to travel diagonally forward to the right as described above in FIG. 2(c), when the driving mode is a right turn, the vehicle travels forward while also traveling to the right. Therefore, the area on the right side of the entry area Sa4 is set so that the front side of the area (i.e., the position where the traveling direction is to the right) is wider than the rear side of the area (i.e., the position where the traveling direction is forward). This entry area Sa4 can cover the area into which the vehicle body 2 enters when the traveling direction changes from forward to right by turning right. On the other hand, when the driving mode is a right turn, the vehicle body 2 does not enter the rear and left sides, so the entry area Sa4 is not set on the rear and left sides of the vehicle body 2.

[0043] With reference to FIG. 2(e), the approach area Sa5, which is the approach area Sa when the driving mode is right turning, will be described. When the driving mode is right turning, the traveling direction of the automatic guided vehicle 1 is turning to the right, so the approach area Sa5 in this case is set to the front side, left side, and right side of the vehicle body 2 as shown in FIG. 2(e). The approach area Sa5 is shaped to follow the turning to the right of the vehicle body 2. Specifically, the approach area Sa5 is composed of two areas: an area surrounded by the arc C3, the normal line N2, the perpendicular line N3, and the front end and right end of the vehicle body 2, and an area surrounded by the perpendicular line N4, the arc C5, and the left end of the vehicle body 2.

[0044] The arc C3 is an arc that starts at the angle R1 and is drawn with a turning radius centered on the turning center. The length of the arc C3 is set to a length approximately equal to the above offset amount, similar to the above arc C1. The normal line N2 is a normal line extending from an end point E3 facing the angle R1 in the arc C3. An end point E4 facing the end point E3 in the normal line N2 is set to be an intersection point between the normal line N2 and the arc C4 that starts at the angle R2 and is drawn with a turning radius centered on the turning center. The length of the arc C4 is also set to a length approximately equal to the above offset amount. The perpendicular line N3 is a perpendicular line to the normal line N2 that starts at the end point E4. The area surrounded by such arc C3, the normal line N2, the perpendicular line N3, and the front end and right end of the vehicle body 2 is set to the area on the front side and right side of the vehicle body 2 in the approach area Sa5.

[0045] Perpendicular line N4 is a perpendicular line to normal line N2 starting from end point E3. Arc C5 is a circular arc drawn with a turning radius centered on the turning center and starting from corner R4 at the rear left end of vehicle body 2. The intersection of perpendicular line N4 and arc C5 is intersection E5. The area surrounded by such perpendicular line N4, arc C5, and the left end of vehicle body 2 is the area on the left side of vehicle body 2 in approach area Sa5.

[0046] Unlike the case of turning right described above in FIG. 2(d), when the driving mode is turning right, the direction of travel of the rear wheels 3b of the vehicle body 2 is directed to the left front, so the left side of the vehicle body 2 (particularly corner R4) is also a position into which the vehicle body 2 enters. Therefore, by setting the entry area Sa5 on the left side of the vehicle body 2 in addition to the front and right sides of the vehicle body 2, it is possible to cover the area into which the vehicle body 2 enters when turning right. On the other hand, when the driving mode is turning right, the vehicle body 2 does not enter the rear side thereof, so the entry area Sa5 is not set on the rear side of the vehicle body 2.

[0047] The lengths of the arcs C3 and C4 are not limited to the lengths based on the offset amounts, and may be longer than the offset amounts. Furthermore, equations for calculating the lengths of the arcs C3, C4, the normal line N2, the perpendicular line N3, the perpendicular line N4, and the arc C5 may be prepared in advance, and these lengths may be calculated from the equations.

[0048] 2(e) has been described with respect to the entry area Sa5 in the case where the turning center (not shown) is set to the right of the automated guided vehicle 1, but the position of the turning center is not limited to the right of the automated guided vehicle 1. When the turning center is set to a position other than the right, the entry area Sa5 may be set to an area into which the vehicle body 2 enters when traveling based on the position of the turning center, instead of the entry area Sa5 in FIG.

[0049] Finally, referring to Fig. 2(f), the approach area Sa6, which is the approach area Sa when the driving mode is rotation, will be described. When the driving mode is rotation, the automatic guided vehicle 1 rotates on the spot, so the approach area Sa6 in this case is set to the entire circumference of the vehicle body 2 as shown in Fig. 2(f). In other words, the approach area Sa6 is shaped to match the position where the corners R1 to R4 of the vehicle body 2 enter when rotating.

[0050] Specifically, the approach area Sa6 is defined as a circle centered on the turning center and passing through the point among the corners R1 to R4 of the vehicle body 2 that is farthest from the center of the vehicle body 2, or a region surrounded by a circular arc centered on the turning center and extending from the corner R1, the corner R2, the corner R3, and the corner R4 of the vehicle body 2. Although the approach area Sa6 is set all around, by limiting its shape to the positions into which the corners R1 to R4 of the vehicle body 2 approach when rotating, the approach area Sa6 can be defined as a region into which the vehicle body 2 can approach, while keeping its area to a necessary minimum.

[0051] In this way, in the automated guided vehicle 1 of this embodiment, an entry area Sa based on the position where the vehicle body 2 enters is provided for each travel mode, and an obstacle in the entry area Sa corresponding to the travel mode is detected from the situation of the entire circumference of the vehicle body 2 acquired from the obstacle sensors 4f, 4b. Since the entry area Sa is an area based on the travel mode, it is an area into which the automated guided vehicle 1 actually enters regardless of the environment in which the automated guided vehicle 1 travels. By detecting an obstacle present in such an entry area Sa, an obstacle that hinders the automated guided vehicle 1 from traveling can be quickly and accurately detected.

[0052] Since the entry area Sa is an area based on the driving mode, for example, as in the case of a right turn in Fig. 2(d), not only the forward side, which is the current traveling direction of the automated guided vehicle 1, but also the right side into which the automated guided vehicle 1 will enter in the future can be included in the entry area Sa. By detecting obstacles from the entry area Sa into which the automated guided vehicle 1 can enter in the present and future, obstacles that may impede the travel of the automated guided vehicle 1 can be detected more accurately.

[0053] In such an approach area Sa, if an obstacle is present in the current traveling direction of the automated guided vehicle 1 and within the stopping distance, the automated guided vehicle 1 stops traveling and transmits a message to the upper process controller that the automated guided vehicle 1 has stopped. Among these, the current traveling direction of the automated guided vehicle 1 is set to forward, right, right diagonal, and full circle in the case of the traveling modes in which the traveling direction is constant, namely, straight ahead, right lateral, right diagonal, and rotation. On the other hand, in the case of the traveling modes in which the direction is changed, namely, right turn and right turn, the direction is determined according to the position of the automated guided vehicle 1 at that time and the position of the turning center of the automated guided vehicle 1 when changing direction.

[0054] Specifically, the smaller the distance between the turning center and the position of the automated guided vehicle 1, the more the traveling direction is set to the right, and the greater the distance between the turning center and the position of the automated guided vehicle 1, the more the traveling direction of the automated guided vehicle 1 is set to the front. Therefore, the closer the turning center is to the automated guided vehicle 1, the smaller the turning radius, which is the radius of the virtual arc (i.e., the length of the line connecting the turning center and the axle 3a), becomes, so the automated guided vehicle 1 moves with greater maneuverability to the right. On the other hand, the closer the turning center is to the automated guided vehicle 1, the larger the turning radius becomes, so the automated guided vehicle 1 moves approximately forward.

[0055] The stopping distance is the distance required for the automated guided vehicle 1 to stop when it receives a stop command from the host process controller and decelerates at a predetermined deceleration from its current traveling speed. Specifically, the stopping distance is the sum of the free running distance D1, which is the distance from when the automated guided vehicle 1 receives a stop command from the host process controller until the automated guided vehicle 1 actually starts to stop, and the actual braking distance D2, which is the distance from when the automated guided vehicle 1 actually starts to stop until it completely stops.

[0056] If the running speed is V and the time from when the automatic guided vehicle 1 receives a stop command from the upper process computer to when it actually starts to stop is T1 (for example, 1 second), the free running distance D1 is calculated as V × T1. Furthermore, the deceleration of the automatic guided vehicle 1 is A (for example, -0.3 m / s 2 ), the time T2 from when the automated guided vehicle 1 actually starts to stop until it stops completely is calculated as "V / A". From the running speed V, deceleration A, and time T2, the actual braking distance D2 is calculated as "V x T2 + 1 / 2 x A x (T2) 2 " is calculated as follows.

[0057] Among obstacles located in the travel direction within the entry area Sa, an object whose distance from the automated guided vehicle 1 is within the stopping distance is detected as an obstacle, and the automated guided vehicle 1 is stopped. Therefore, even if an object is located in the travel direction within the entry area Sa, if it is farther away than the stopping distance of the automated guided vehicle 1, the automated guided vehicle 1 continues traveling as long as the automated guided vehicle 1 can avoid contact with the object by approaching further and then starting to brake and stopping. This prevents the automated guided vehicle 1 from stopping unnecessarily, and the automated guided vehicle 1 can be operated efficiently. On the other hand, if an object is located in the travel direction within the entry area Sa and the distance from the object is equal to or less than the stopping distance, the object is detected as an obstacle and the automated guided vehicle 1 is stopped, so that contact with the obstacle can be reliably avoided.

[0058] The decision to stop the automated guided vehicle 1 is not limited to being made by the upper process controller, and may be made by the automated guided vehicle 1 itself, for example. In particular, it is desirable for the automated guided vehicle 1 to make the decision to stop when the distance between an obstacle and the automated guided vehicle 1 is less than the stopping distance. This allows the automated guided vehicle 1 to be stopped reliably even if the stop command from the upper process controller is delayed due to a communication failure or the like.

[0059] Also, the automated guided vehicle 1 may be stopped when the distance between the obstacle and the automated guided vehicle 1 becomes a predetermined distance before it becomes equal to or smaller than the stopping distance (for example, when the distance between the obstacle and the automated guided vehicle 1 becomes 1.2 times the stopping distance). This makes it possible to more reliably avoid contact with the obstacle.

[0060] Next, the electrical configuration of the automated guided vehicle 1 will be described with reference to Fig. 3. Fig. 3(a) is a block diagram showing the electrical configuration of the automated guided vehicle 1. The automated guided vehicle 1 includes a CPU 10, a flash ROM 11, and a RAM 12, which are connected to an input / output port 14 via a bus line 13. The above-mentioned rotation drive device 3d, steering drive device 3e, front obstacle sensor 4f, and rear obstacle sensor 4b are connected to the input / output port 14. Note that multiple rotation drive devices 3d and steering drive devices 3e are provided in the automated guided vehicle 1, but in Fig. 3(a), each of these is shown collectively as one unit.

[0061] The CPU 10 is a computing device that controls each unit connected to the bus line 13 and the input / output port 14. The flash ROM 11 is a rewritable non-volatile memory, and stores a control program 11a and access area data 11b. When the control program 11a is executed by the CPU 10, the main process of Fig. 4 is executed. The access area data 11b will be described with reference to Fig. 3(b).

[0062] Fig. 3(b) is a diagram showing the entry area data 11b in a schematic manner. As shown in Fig. 3(b), the entry area data 11b stores information on the entry area Sa corresponding to each driving mode. Note that Fig. 3(b) shows an example in which the entry areas Sa1 to Sa6 corresponding to the driving modes of straight ahead, right lateral movement, right diagonal movement, right turn, and right turn are stored in the entry area data 11b, but the entry area Sa corresponding to other driving modes may be stored.

[0063] Returning to Fig. 3(a), the RAM 12 is a memory for rewritably storing various work data, flags, and the like when the CPU 10 executes the control program 11a, etc., and stores a driving mode memory 12a in which a driving mode is stored, and an entry area memory 12b in which an entry area Sa is stored.

[0064] Next, the main processing executed by the CPU 10 will be described with reference to Fig. 4. Fig. 4 is a flowchart of the main processing. The main processing is executed after the automatic guided vehicle 1 is powered on. In the main processing, the driving mode received from the upper process computer is first obtained and stored in the driving mode memory 12a (S1). After the processing of S1, the entry area Sa corresponding to the driving mode in the driving mode memory 12a is obtained from the entry area data 11b and stored in the entry area memory 12b (S2).

[0065] After the process of S2, the current traveling direction of the automated guided vehicle 1 is acquired (S3). As described above in FIG. 2, the traveling direction of the automated guided vehicle 1 is acquired according to the traveling mode in the traveling mode memory 12a, the position of the automated guided vehicle 1, or the turning radius of the automated guided vehicle 1. After the process of S3, the traveling speed of the automated guided vehicle 1 is acquired (S4). A known method is used to acquire the traveling speed, and for example, the traveling speed may be acquired from the rotation drive device 3d, or the traveling speed may be acquired by another method. After the process of S4, the stopping distance is calculated from the acquired traveling speed and the above-mentioned predetermined deceleration by the method described above in FIG. 2 (S5).

[0066] After the process of S5, the surroundings of the vehicle body 2 detected by the obstacle sensors 4f, 4b are acquired (S6), and from the acquired surroundings of the vehicle body 2, obstacles located within the entry area Sa of the entry area memory 12b are detected (S7). After the process of S7, it is confirmed whether an obstacle exists in the traveling direction acquired in the process of S3 within the entry area Sa of the entry area memory 12b in the detection result by the process of S7 (S8).

[0067] In the process of S8, if an obstacle is present in the traveling direction (S8: Yes), it is further confirmed whether the obstacle is located within the stopping distance acquired in the process of S5 (S9). In the process of S9, if the obstacle is located within the stopping distance (S9: Yes), the automatic guided vehicle 1 stops traveling, and a message that the automatic guided vehicle 1 has stopped is transmitted to the upper process controller (S10).

[0068] On the other hand, if there is no obstacle in the direction of travel in the processing of S8 (S8: No), if there is no obstacle located within the stopping distance in the processing of S9 (S9: No), or after processing of S10, other processing of the unmanned guided vehicle 1 is executed (S11), and the processing from S1 onwards is repeated.

[0069] The present invention has been described above based on an embodiment, but the present invention is not limited to the above-described embodiment, and it can be easily inferred that various improvements and modifications are possible within the scope of the present invention.

[0070] In the above embodiment, the entry area Sa is set based on a case where the travel speed of the automated guided vehicle 1 is 0.5 m / s and the stopping distance is 2 m, but this is not limited thereto. The travel speed as a reference for the entry area Sa may be 0.5 m / s or more or 0.5 m / s or less. The stopping distance may also be 2 m or more or 2 m or less depending on the travel speed and braking ability of the automated guided vehicle 1. Alternatively, in consideration of position correction during travel, an area further outside the entry area Sa (for example, an area about 1 to 2 m outside from the edge of the entry area Sa) may be set as a preliminary entry area, and obstacles located in the preliminary entry area may also be detected.

[0071] Also, as shown in Figures 5(a) and (b), the size of the entry area Sa may be changed according to the magnitude of the running speed V. Figure 5(a) is a diagram showing an entry area Sa1 in a modified example in which the running mode is straight ahead, and Figure 5(b) is a diagram showing an entry area Sa1' in which the running speed is higher than that in Figure 5(a). Figures 5(a) and (b) both show a case in which the running mode is straight ahead, and the running speed V2 of the automatic guided vehicle 50 in Figure 5(b) is higher than the running speed V1 in Figure 5(a).

[0072] Since the automated guided vehicle 50 in FIG. 5(b) has a higher travel speed V than the automated guided vehicle 50 in FIG. 5(a), the distance that the automated guided vehicle 50 travels in the traveling direction per unit time is longer. Therefore, the area on the traveling direction side of the entry area Sa is expanded in the traveling direction based on the travel speed V multiplied by a predetermined coefficient. As a result, the entry area Sa1' in FIG. 5(b), which has a higher travel speed V than FIG. 5(a), is expanded in the traveling direction more than the entry area Sa in FIG. 5(a), so that obstacles that the automated guided vehicle 50 may come into contact with when traveling can be detected more accurately.

[0073] Furthermore, when the driving mode is a right turn or a right turn, the size of the entry area Sa may be changed according to the length of the turning radius D. Fig. 5(c) is a diagram showing an entry area Sa4 when the driving mode is a right turn in the modified example, and Fig. 5(d) is a diagram showing an entry area Sa4' when the driving mode is a right turn in the modified example and the turning radius D is smaller than that in Fig. 5(c).

[0074] In both Figures 5(c) and 5(d), the driving mode is a right turn, and the turning center Ct4 in Figure 5(d) is closer to the vehicle body 2 than the turning center Ct3 in Figure 5(c). Therefore, the turning radius D4 of the automated guided vehicle 70 in Figure 5(d) is smaller than the turning radius D3 of the automated guided vehicle 70 in Figure 5(c), so the automated guided vehicle 70 in Figure 5(d) becomes more maneuverable and is more likely to come into contact with an obstacle.

[0075] Therefore, the area on the turning center Ct side of the entry area Sa is expanded toward the turning center Ct based on a predetermined coefficient multiplied inversely proportional to the length of the turning radius D. Specifically, the smaller the turning radius D, the more arc-shaped the entry area Sa becomes, and the larger the turning radius D, the more rectangular the entry area Sa becomes. As a result, the entry area Sa4' in FIG. 5(d), which has a smaller turning radius D than that in FIG. 5(c), is expanded toward the turning center Ct more than the entry area Sa4 in FIG. 5(c), so that obstacles that may come into contact with the maneuverable automated guided vehicle 70 while traveling can be detected more accurately.

[0076] In the above embodiment, the driving modes of straight ahead, right diagonal, right turn, and right turn are all forward, but this is not limited thereto, and may also include a driving mode of reverse. For example, right turn backward is a driving mode in which the vehicle turns right while moving backward, and the entry area Sa in this case may be the entry area Sa4 in the case of right turn reversed front to back. Similarly, right turn backward is a driving mode in which the vehicle turns right while moving backward, and the entry area Sa in this case may be the entry area Sa5 in the case of right turn reversed front to back. Furthermore, these may be reversed front to back and left to right to determine a driving mode of reverse, left lateral travel, etc.

[0077] In the above embodiment, the automated guided vehicle 1 is stopped (S10) when an obstacle is present in the approach area Sa in the travel direction (S8) and the obstacle is within the stopping distance (S9) by the processes of S8 to S10 in Fig. 4, but this is not limited to the above. For example, the process of S9 may be omitted and the automated guided vehicle 1 may be stopped when an obstacle is present in the approach area Sa in the travel direction, or the process of S8 may be omitted and the automated guided vehicle 1 may be stopped when an obstacle is present within the stopping distance in the approach area Sa. Alternatively, both the processes of S8 and S9 may be omitted and instead the automated guided vehicle 1 may be stopped when an obstacle is present within the stopping distance in the approach area Sa.

[0078] In the above embodiment, the automatic guided vehicle 1 is configured to have the front obstacle sensor 4f and the rear obstacle sensor 4b, but this is not limited to the above. For example, the number of obstacle sensors may be three or more, or one. In particular, when there is one obstacle sensor, it is necessary to detect obstacles in the entire entry area Sa in all driving modes by the one obstacle sensor. Therefore, it is preferable that the obstacle sensor is a sensor that can simultaneously or periodically scan and detect obstacles in the entire entry area Sa in all driving modes, or a sensor that can simultaneously or periodically scan and detect the entire circumference of the vehicle body 2 in a short time. In addition to the front obstacle sensor 4f and the rear obstacle sensor 4b, a sensor that detects objects may be further added to the automatic guided vehicle 1.

[0079] In addition, the forward obstacle sensor 4f is not limited to being provided at the right end of the front of the vehicle body 2, and may be provided at any position on the forward side of the vehicle body 2, such as the left end of the front of the vehicle body 2. Similarly, the rear obstacle sensor 4b is not limited to being provided at the left end of the rearmost part of the vehicle body 2, and may be provided at any position on the rear side of the vehicle body 2, such as the right end of the rearmost part of the vehicle body 2.

[0080] In the above embodiment, the driving mode is obtained from the upper process controller, but this is not limited to this. For example, a driving mode for the automatic guided vehicle 1 to reach the destination may be stored in advance in the flash ROM 11, and the driving mode may be appropriately obtained from the flash ROM 11. In the above embodiment, the entry area Sa is obtained from the entry area data 11b, but this is not limited to this. For example, the corresponding entry area Sa may be transmitted from the upper process controller together with the driving mode, and the automatic guided vehicle 1 may detect an obstacle using the entry area Sa received from the upper process controller.

[0081] In the above embodiment, the vehicle body 2 is formed in a rectangular shape when viewed from above, but the present invention is not limited to this, and the vehicle body 2 may be formed in any shape. In that case, the entry area Sa stored in the entry area data 11b may be an entry area Sa having a shape corresponding to the shape of the vehicle body 2.

[0082] In the above embodiment, the automatic guided vehicle 1 has been used as an example of a vehicle, but the present invention is not necessarily limited to this, and may be applied to other vehicles such as unit carriers and automobiles. [Explanation of symbols]

[0083] 1,50,70 Automated guided vehicle (vehicle) 2. Body 4f Forward obstacle sensor (part of the detection means) 4b Rear obstacle sensor (part of the detection means) Ct, Ct3, Ct4 turning center D, D3, D4 turning radius V,V1,V2 Traveling speed S1 Driving mode acquisition means, driving mode acquisition step S2 Area acquisition means, area acquisition step S3 Direction acquisition means S4 Traveling speed acquisition means S5 Stopping distance acquisition means S6 Part of the detection means, detection step S7 Obstacle detection means, obstacle detection step S8~S10 Stopping means

Claims

1. A vehicle including a vehicle body, a detection means for detecting a surrounding situation of the vehicle body, and an obstacle detection means for detecting an obstacle based on a detection result of the detection means, A driving mode acquisition means for acquiring a driving mode of the vehicle; an area acquisition means for acquiring an entry area around the vehicle body, the entry area being an area into which the vehicle body enters while traveling in the traveling mode acquired by the traveling mode acquisition means; The obstacle detection means detects an obstacle present within the approach area obtained by the area acquisition means in response to detection by the detection means.

2. A traveling speed acquisition means for acquiring a traveling speed of the vehicle; a stopping distance acquisition means for acquiring a stopping distance, which is a distance required for the vehicle to stop when the vehicle is stopped from the traveling speed acquired by the traveling speed acquisition means; 2. The vehicle according to claim 1, further comprising a stopping means for stopping the vehicle when an obstacle detected by the obstacle detection means is present within the stopping distance detected by the stopping distance detection means.

3. A traveling speed acquisition means for acquiring a traveling speed of the vehicle; A traveling direction acquisition means for acquiring a traveling direction of the vehicle; an area change means for changing a size of an area of ​​the approach area acquired by the area acquisition means on the side of the traveling direction acquired by the traveling direction acquisition means in accordance with the traveling speed acquired by the traveling speed acquisition means, 2. The vehicle according to claim 1, wherein the obstacle detection means detects an obstacle present within the approach area changed by the area change means based on the detection result of the detection means.

4. The vehicle according to claim 3, characterized in that the area changing means expands in the travel direction the area of ​​the entry area acquired by the area acquisition means on the travel direction side acquired by the travel direction acquisition means, as the travel speed acquired by the travel speed acquisition means increases.

5. A turning center acquisition means for acquiring a turning center of the vehicle; a turning radius acquisition means for acquiring a turning radius, which is a distance between the turning center acquired by the turning center acquisition means and an axle of the vehicle; an area change means for changing a size of an area on the turning center side acquired by the turning center acquisition means of the approach area acquired by the area acquisition means in accordance with the turning radius acquired by the turning radius acquisition means, 2. The vehicle according to claim 1, wherein the obstacle detection means detects an obstacle present within the approach area changed by the area change means based on the detection result of the detection means.

6. 6. The vehicle according to claim 5, wherein the area changing means expands the area on the side of the turning center acquired by the turning center acquisition means in the direction of the turning center as the turning radius acquired by the turning radius acquisition means becomes smaller.

7. A detection step of detecting a situation around a vehicle body of the vehicle; and an obstacle detection step of detecting an obstacle from a detection result of the detection step, A driving mode acquisition step of acquiring a driving mode of the vehicle; and a region acquisition step of acquiring an entry region around the vehicle body, the entry region being a region into which the vehicle body enters while traveling in the traveling mode acquired in the traveling mode acquisition step, The obstacle detection method according to claim 1, wherein the obstacle detection step detects an obstacle present within the approach area acquired in the area acquisition step in the detection result of the detection step.

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