Automatic traveling vehicle

Abstract

To provide an automatic traveling vehicle that does not require a location of an uphill road or a convex-concave road to be set in advance in a controller.SOLUTION: An automatic traveling vehicle capable of automatically traveling includes: a vehicle body 11; a traveling motor mounted on the vehicle body 11; a first sensor 34 for detecting an obstruction in a traveling direction; and a controller for controlling the traveling motor. The automatic traveling vehicle has a second sensor 35 for detecting an obstruction in a traveling direction, wherein: a first detection range A of the first sensor 34 is set planarly at a constant height from a road surface and can be reduced in a traveling direction; a second detection range B of the second sensor 35 is set below the first detection range, away from the road surface, and toward a traveling direction; a tip portion of the second detection range B in a traveling direction is located forward of a tip portion of the first detection range A when not contracted; and the controller reduces the first detection range A when the second sensor 35 detects an obstruction and the first sensor 34 does not detect an obstruction.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to autonomous vehicles. [Background technology]

[0002] Known examples of conventional autonomous vehicle technology include the autonomous vehicle disclosed in Patent Document 1. In the autonomous vehicle disclosed in Patent Document 1, a first obstacle sensor is provided at a height from the road surface equal to or less than a specified height, and a first obstacle detection area for detecting obstacles is set in front of the first sensor 34. The vehicle body is provided with a second obstacle sensor at a higher position than the first obstacle sensor for detecting obstacles around the vehicle body, and a second obstacle detection area for detecting obstacles is set in front of the second obstacle sensor. A controller controls the first obstacle sensor to move the front end of the first obstacle detection area closer to the vehicle body so that the road surface does not interfere with the first obstacle detection area while the vehicle is traveling.

[0003] According to the autonomous vehicle of Patent Document 1, even if the road surface is an uphill or uneven road, the front end of the first deceleration detection area moves back, preventing interference with the first obstacle detection area on the road surface. As a result, it is possible to prevent the first obstacle sensor from erroneously detecting an obstacle on the road surface and prevent deceleration due to the erroneous detection. Incidentally, by setting the position of the uphill or uneven road in advance, the controller can grasp the position of the uphill or uneven road while traveling. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-117433 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the self-driving vehicle disclosed in Patent Document 1 requires the location of an uphill or uneven road to be set in advance in a controller, and the task of setting the location of the uphill or uneven road in advance in a controller is problematic in that it is time-consuming and cumbersome. Furthermore, if the location of the uphill or uneven road is set in advance in a controller manually, there is a risk of input errors. Incidentally, while it is conceivable to have the location of the uphill or uneven road stored in an environmental map by driving the self-driving vehicle without manual intervention, this requires the self-driving vehicle to be driven, which takes a great deal of time.

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an automated vehicle that does not require the location of an uphill or uneven road to be preset in a controller. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides an autonomous vehicle capable of autonomous driving, comprising a vehicle body, a traction motor mounted on the vehicle body, a first sensor that detects obstacles in the direction of travel, and a controller that controls the traction motor, wherein the controller controls the traction motor so that it slows down or stops when the first sensor detects an obstacle, and the vehicle also comprises a second sensor that detects obstacles in the direction of travel, wherein a first detection range that is the detection range of the first sensor is set in a plane at a constant height from the road surface and can be reduced in the direction of travel, a second detection range that is the detection range of the second sensor is set below the first detection range and away from the road surface, facing the direction of travel, and is set to be located inside the vehicle body in the width direction of the vehicle body, the end of the second detection range in the direction of travel is located forward of the end of the first detection range when not reduced, and the controller reduces the first detection range when the second sensor detects an obstacle and the first sensor does not detect an obstacle.

[0008] In the present invention, the controller reduces the first detection range when the second sensor detects an obstacle but the first sensor does not. Therefore, if the obstacle detected by the second sensor is an uphill or uneven road, the first detection range of the first sensor is reduced, so that the first sensor does not detect the uphill or uneven road, and the autonomous vehicle can enter the uphill or uneven road without slowing down or stopping. Furthermore, if the controller detects an obstacle within the reduced first detection range after the second sensor detects an obstacle, it can determine that the obstacle is not an uphill or uneven road.

[0009] In the above-described autonomous vehicle, the controller may be configured to reduce the first detection range when the detection time taken for the second sensor to detect an obstacle exceeds a preset time. In this case, the controller reduces the first detection range when the detection time it takes for the second sensor to detect an obstacle exceeds a preset time, so that even if the vehicle body tilts momentarily due to some cause such as vibration, the controller will not distinguish a flat road surface as an uphill or uneven road.

[0010] In the above-described autonomous vehicle, the controller may be configured to change the lengths of the first detection range and the second detection range in the traveling direction in accordance with the traveling speed. In this case, by changing the lengths of the first detection range and the second detection range in the traveling direction according to the traveling speed, when the controller detects an obstacle using the first sensor or the second sensor and then slows down or stops the autonomous vehicle, it is possible to slow down or stop the autonomous vehicle without interfering with the obstacle.

[0011] In the above-described autonomous vehicle, the second detection range may be a two-dimensional area set in a direction intersecting the first detection range. In this case, since the second detection range is a two-dimensional area set in a direction intersecting with the first detection range, it is possible to detect obstacles that exist in a direction intersecting with the first detection range.

[0012] In addition, in the above-mentioned autonomous vehicle, the second detection range may be divided into a lower detection area and an upper detection area, and the controller may be configured to reduce the first detection range when an obstacle is detected only in the lower detection area, and not reduce the first detection range when an obstacle is detected in the upper detection area. In this case, the controller reduces the first detection range when an obstacle is detected only in the lower detection area, and does not reduce the first detection range when an obstacle is detected in the upper detection area, so that it is possible to distinguish between an uphill or uneven road and an obstacle.

[0013] In addition, in the above-mentioned autonomous vehicle, the upper detection area may be divided into an upper first detection area and an upper second detection area in the direction of travel, and the controller may be configured to decelerate when an obstacle is detected in the upper first detection area. In this case, when an obstacle is detected in the upper first detection area, the controller determines that the detected obstacle is not an uphill or uneven road, and so decelerates the autonomous vehicle, allowing it to avoid collision with the obstacle.

[0014] In addition, in the above-mentioned autonomous vehicle, a third sensor for detecting obstacles is provided above the first sensor, and a third detection range, which is the detection range of the third sensor, is set in a plane at a certain height from the first detection range, and the controller may be configured to decelerate when the third sensor detects an obstacle in the third detection range. In this case, a third sensor for detecting obstacles is provided above the first sensor, and the third detection range of the third sensor is set in a plane at a certain height from the first detection range. Therefore, even if an obstacle exists above the first detection range but out of the second detection range, the third sensor can detect the obstacle, and the controller can avoid interference with the detected obstacle. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide an automated vehicle that does not require the location of an uphill road or an uneven road to be preset in a controller. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a side view of a towing vehicle according to an embodiment of the present invention. [Figure 2] 1 is a perspective view of a towing vehicle according to an embodiment of the present invention. [Figure 3] 1 is a schematic configuration diagram of a towing vehicle according to an embodiment of the present invention; [Figure 4] FIG. 1(a) is a plan view showing the towing vehicle and the first detection range, and FIG. 1(b) is a plan view showing the towing vehicle and the third detection range. [Figure 5] FIG. 4 is a side view showing the relationship between the second detection range, the first detection range, and the third detection range in the towing vehicle. [Figure 6] FIG. 10 is a flow diagram for a towing vehicle traveling uphill. [Figure 7] FIG. 10 is a side view showing the towing vehicle entering an uphill road. [Figure 8] FIG. 10 is a side view showing the relationship between the first detection range and the second detection range in the towing vehicle according to the second embodiment. [Figure 9] FIG. 10 is a perspective view showing a towing vehicle according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0017] (First embodiment) A towing vehicle as an autonomous vehicle according to a first embodiment will be described below with reference to the drawings. The towing vehicle of this embodiment is an autonomous towing vehicle that estimates its own position while creating an environmental map and traveling autonomously. However, the towing vehicle of this embodiment is a small unmanned towing vehicle equipped with a driver's seat so that it can also be driven by a driver. Note that the directions "forward / backward," "left / right," and "up / down" are determined based on the driver's seat of the towing vehicle.

[0018] As shown in Fig. 1, front wheels 12 are provided at the front of a body 11 of a towing vehicle 10, and rear wheels 13 are provided at the rear of the body 11. The front wheels 12 are steered wheels, and the rear wheels 13 are drive wheels. A driver's seat 14 is provided near the center of the body 11. As shown in Figs. 1 and 2, the driver's seat 14 is equipped with a standing-type driver's seat 15 and a steering lever 16 to enable manned driving.

[0019] A battery room (not shown) is located behind the driver's seat 14 in the vehicle body 11. The battery room is a space that can accommodate a battery 17. The upper part of the battery room is covered by an openable and closable cover 18 that the vehicle body 11 is provided with. As shown in FIG. 1, a drawbar device 19 that couples a towed vehicle (not shown) such as a bogie is provided at the rear of the vehicle body 11. By operating the drawbar device 19, the transport vehicle, which is the towed vehicle, is coupled to or uncoupled from the towing vehicle 10.

[0020] As shown in Fig. 3, the towing vehicle 10 includes a traveling drive device 20 that generates a driving force to drive the rear wheels 13, and a steering device 21 that steers the front wheels 12. The traveling drive device 20 includes a drive motor 22 that serves as a traveling motor for rotating the rear wheels 13, and a motor driver 23 that drives the drive motor 22. The steering device 21 includes a drive motor 24 that serves as a steering motor for driving the front wheels 12, and a motor driver 25 that drives the drive motor 24.

[0021] The vehicle body 11 is equipped with a controller 26 that controls the motor drivers 23, 25. The motor driver 23 controls the rotation speed of the drive motor 22 in response to commands from the controller 26. Therefore, the controller 26 controls the acceleration and deceleration (braking) of the towing vehicle 10 by controlling the traveling drive device 20. In addition, the motor driver 25 controls the rotation amount of the drive motor 24 in response to commands from the controller 26.

[0022] 3, the controller 26 includes a CPU 27 and a storage unit 28 including RAM, ROM, etc. The controller 26 may include dedicated hardware for executing at least some of the various processes, such as an application specific integrated circuit (ASIC). The controller 26 may be configured as one or more processors that operate according to a computer program, one or more dedicated hardware circuits such as ASICs, or a circuit including a combination of these.

[0023] The memory unit 28 stores program code or instructions configured to cause the CPU 27 to execute processing. The memory unit 28 stores various programs for controlling the towing vehicle 10, as well as an environmental map of the moving space in which the towing vehicle 10 moves. The environmental map is a map created by the towing vehicle 10 as it moves through the moving space. The technology for simultaneously estimating the self-position of the towing vehicle 10 and constructing the environmental map is called SLAM (Simultaneous Localization and Mapping). The memory unit 28, i.e., the computer-readable medium, includes anything that can be accessed by a general-purpose or dedicated computer.

[0024] As shown in FIG. 2 , a portal frame 30 is provided near the front of the vehicle body 11. The portal frame 30 has a pair of left and right support pillars 31 and a cross member 32 that is horizontally supported on the tops of the support pillars 31. An environmental sensor 33 is provided in front of the portal frame 30. The environmental sensor 33 is a sensor that detects the surroundings including the area in front of the vehicle body 11, and is, for example, a 3D-LiDAR. The environmental sensor 33 is connected to the controller 26. The controller 26 generates an environmental map while estimating the self-position of the towing vehicle 10 based on the point cloud detected by the environmental sensor 33.

[0025] A first sensor 34 is provided near the road surface F at the front of the vehicle body 11. The first sensor 34 is mounted on the vehicle body 11 so as to be no higher than a predetermined height (200 mm) from the road surface F. The first sensor 34 is a laser sensor, and as shown in FIGS. 4(a) and 5, it scans a preset first detection range A with laser light. The optical axis of the laser light emitted from the first sensor 34 extends substantially horizontally when the vehicle body 11 is in a horizontal position, and tilts in accordance with the fore-and-aft tilt of the vehicle body 11. The first detection range A set by the first sensor 34 is a rectangular two-dimensional area, and its left-to-right width is set to be greater than the width of the towing dolly (not shown) towed by the towing vehicle 10. The first sensor 34 is connected to the controller 26.

[0026] Although not shown, the first detection range A is divided into three detection zones in the longitudinal direction. When the controller 26 detects an obstacle in the detection zone closest to the vehicle body 11 in the first detection range A, the controller 26 brings the towing vehicle 10 to an abnormal stop. If the abnormal state of the towing vehicle 10 is not resolved after the abnormal stop, the towing vehicle 10 cannot resume autonomous traveling. When the controller 26 detects an obstacle in the detection zone set in front of the detection zone closest to the vehicle body 11 in the first detection range A, the controller 26 determines that there is no abnormality and stops the towing vehicle 10. If the obstacle is removed after the towing vehicle 10 has stopped, the towing vehicle 10 can resume autonomous traveling. In front of the detection zone where the controller 26 determines that there is no abnormality and stops the towing vehicle 10, i.e., the detection zone farthest from the vehicle body 11 in the first detection range A, the controller 26 determines that deceleration is necessary and brakes the towing vehicle 10 to slow down. If the obstacle is removed during deceleration, the towing vehicle 10 can increase its speed.

[0027] The first detection range A varies depending on the speed of the towing vehicle 10. As the speed of the towing vehicle 10 increases, the length of the first detection range A in the front-to-rear direction increases, and as the speed decreases, the length of the first detection range A in the front-to-rear direction decreases. When the first sensor 34 detects an obstacle, the controller 26 controls the travel drive device 20 to generate a braking force to at least decelerate the vehicle.

[0028] A pair of left and right second sensors 35 are provided at the front of the vehicle body 11. The second sensors 35 are provided on the right and left sides of the front of the vehicle body 11 so as to be higher than the first sensors 34. The second sensors 35 are located inside the vehicle body 11 so as not to protrude from the vehicle body 11 in the width direction of the vehicle body 11. The second sensors 35 are laser sensors that scan a predetermined second detection range B with laser light. The optical axis of the laser light emitted from the second sensor 35 extends substantially vertically when the vehicle body 11 is horizontal and tilts depending on the left-right tilt of the vehicle body 11. As shown in FIG. 5, the second detection range B set by the second sensor 35 is a rectangular two-dimensional area that is substantially perpendicular to the first detection range A. The second detection range B is set so as to be located inside the vehicle body 11 in the width direction of the vehicle body 11.

[0029] A portion of the lower edge of the second detection range B is located lower than the first detection range A and extends forward so as to be approximately parallel to the road surface F. The upper edge of the second detection range B is located higher than the first detection range A, extends forward, and is parallel to the lower edge of the second detection range B. The height of the upper edge of the second detection range B from the road surface F is higher than the vehicle body 11 and lower than the portal frame 30. The leading edge, which is the tip of the second detection range B, is located forward of the tip of the first detection range A when not retracted. The second sensor 35 is connected to the controller 26.

[0030] In this embodiment, the second detection range B is divided into a lower detection range BL and an upper detection range BT. As shown in FIG. 5, the boundary between the lower detection range BL and the upper detection range BT is set at a higher position in the height direction than the first detection range A. The lower detection range BL is set primarily for detecting uphill or uneven roads. The upper detection range BT is set for detecting obstacles other than uphill or uneven roads. In this embodiment, the upper detection range BT is divided in the front-to-rear direction into an upper first detection range BT1 and an upper second detection range BT2. The upper first detection range BT1 is a detection range that immediately decelerates the towing vehicle 10 when an obstacle is present, while the upper second detection range BT2 is a detection range that does not decelerate the towing vehicle 10 even if an obstacle is detected.

[0031] The second detection range B varies depending on the speed of the towing vehicle 10. As the speed of the towing vehicle 10 increases, the length of the second detection range B in the front-to-rear direction increases, and as the speed decreases, the length of the second detection range B in the front-to-rear direction decreases. A fixed distance L is set between the front end of the first detection range A before reduction and the front end of the second detection range B. Distance L is set so that when an uphill or uneven road is detected in the lower detection zone BL of the second detection range B, the first sensor 34 does not detect the uphill or uneven road until the controller 26 determines that the road is an uphill or uneven road.

[0032] A third sensor 36 is mounted on the vehicle body 11. The third sensor 36 is provided at a position sufficiently higher than the first sensor 34 (for example, at a height of approximately 900 mm from the road surface F). The third sensor 36 is a laser sensor that scans a predetermined third detection range C with laser light. The optical axis of the laser light emitted from the third sensor 36 is approximately parallel to the optical axis of the laser light from the first sensor 34. As shown in FIG. 4(b), the third detection range C set by the third sensor 36 is a rectangular area and has approximately the same size as the first detection range A. The third detection range C overlaps with the first detection range A in the vertical direction. The front end of the third detection range C is at approximately the same position as the front end of the first detection range A, but is not retracted like the front end of the first detection range A. The third sensor 36 is connected to the controller 26.

[0033] Although not shown, the third detection range C is divided into two detection zones in the longitudinal direction. When the controller 26 detects an obstacle in the detection zone closest to the vehicle body 11 within the third detection range C, it brings the towing vehicle 10 to an abnormal stop. If the abnormal state of the towing vehicle 10 is not resolved after the abnormal stop, the towing vehicle 10 cannot resume autonomous traveling. When the controller 26 detects an obstacle in the detection zone ahead of the detection zone closest to the vehicle body 11 within the third detection range C, it determines that there is no abnormality and decelerates and stops the towing vehicle 10. If the obstacle is removed during deceleration or after the towing vehicle 10 has stopped, it is possible for the towing vehicle 10 to resume autonomous traveling or increase its speed.

[0034] Incidentally, because the first sensor 34 is located at the front of the vehicle body 11 and close to the road surface F, there is a risk that the first sensor 34 will detect the uphill road S as an obstacle before the towing vehicle 10 enters the uphill road S. Therefore, in this embodiment, when the second sensor 35 detects an obstacle, the controller 26 performs control to determine whether the detected obstacle is an uphill road or an obstacle. Furthermore, if the controller 26 determines that the obstacle is an uphill road, it performs control to reduce the first detection range A so that the front end of the first detection range A moves back. On the other hand, if the controller 26 determines that the obstacle is not an uphill road, it does not move the front end of the first detection range A back, but rather performs control to decelerate and stop the towing vehicle 10.

[0035] Specifically, the controller 26 performs control in accordance with the flow diagram shown in Fig. 6. First, while the towing vehicle 10 is performing autonomous traveling (step S101), the controller 26 determines whether the second sensor 35 has detected an obstacle in the lower detection zone BL while the towing vehicle 10 is traveling autonomously (step S102). When the second sensor 35 detects an obstacle, the controller 26 determines whether the obstacle has been detected in the upper second detection zone BT2 (step S103). Note that when it is determined that the second sensor 35 has not detected an obstacle in the lower detection zone BL, the controller 26 allows the towing vehicle 10 to continue traveling autonomously.

[0036] When the second sensor 35 detects an obstacle and determines that no obstacle is detected in the upper second detection zone BT2, the controller 26 determines whether the detection time for detecting an obstacle in the lower detection zone BL exceeds a set time T (step S104). The set time T is a time that is set in advance in the controller 26. By setting the set time T, even if the vehicle body 11 tilts momentarily due to vibration or the like and the second sensor 35 detects a flat road surface F as an obstacle, the controller 26 will not determine that the detected flat road surface F is an uphill road.

[0037] If it is determined in step S104 that the detection time for detecting an obstacle in the lower detection range BL exceeds the set time T, the controller 26 determines that the obstacle detected in the lower detection range BL is an uphill road (step S105). Then, the controller 26 moves the front end of the first detection range A back (step S106). That is, by moving the front end of the first detection range A back, the first detection range A is reduced. Therefore, when the towing vehicle 10 reaches the front of the uphill road, the first detection range A will not detect the uphill road.

[0038] Next, the controller 26 determines whether an obstacle has been detected in the first detection range A (step S107). If it is determined that an obstacle has been detected in the first detection range A, the controller 26 controls the travel drive device 20 to decelerate or stop the towing vehicle 10 (step S108). If it is determined in step S107 that an obstacle has not been detected in the first detection range A, the controller 26 determines whether an obstacle has not been detected in the lower detection range BL (step S109). If it is determined that an obstacle has not been detected in the lower detection range BL, the controller 26 returns the front end of the first detection range A to its original position (step S110). When an obstacle can no longer be detected in the lower detection range BL, the towing vehicle 10 has transitioned from a flat road to an uphill road. After step S110, the process returns to step S102. Note that if it is determined in step S109 that an obstacle has been detected in the lower detection range BL, the process returns to step S102.

[0039] Incidentally, if it is determined in step S103 that an obstacle has been detected in the upper second detection range BT2, the controller 26 determines that the obstacle detected in the lower detection range BL is an obstacle that will hinder travel (step S111). Next, the controller 26 does not move the front end of the first detection range A backward (step S112). In other words, the position of the front end of the first detection range A is not changed, and the first detection range A is not reduced. Then, the controller 26 proceeds to step S107.

[0040] A program for carrying out control relating to the series of steps (steps S101 to S112) shown in FIG.

[0041] Although not shown in FIG. 6, when an obstacle is detected in the upper first detection range BT1 of the second detection range B or in the third detection range C, the controller 26 decelerates the towing vehicle 10 to stop it regardless of the timing of the detection.

[0042] Next, the autonomous traveling of the towing vehicle 10 according to this embodiment from a flat road to an uphill road will be described. As shown in Fig. 7, when the towing vehicle 10 is traveling autonomously on a flat road surface F, the first sensor 34 scans a first detection range A with a laser beam, and the second sensor 35 scans a second detection range B with a laser beam. Furthermore, the third sensor 36 scans a third detection range C with a laser beam. When a flat road surface F continues ahead of the towing vehicle 10, the first detection range A is not reduced, and the first sensor 34 scans the first detection range A with a laser beam.

[0043] When an upwardly sloping road surface (hereinafter referred to as an "uphill road") S exists ahead of the towing vehicle 10, the second sensor 35 detects the uphill road S. Specifically, the second sensor 35 detects the uphill road S in the lower detection zone BL of the second detection range B. At this time, the controller 26 is unable to determine whether the obstacle detected by the second sensor 35 in the lower detection zone BL is an uphill road S or an obstacle itself. Therefore, the controller 26 next determines whether an obstacle is detected in the upper second detection zone BT2 of the second detection range B. If it is determined that no obstacle is detected in the upper second detection zone BT2, the controller 26 then determines whether the detection time of the uphill road S in the lower detection zone BL has exceeded the set time T.

[0044] When it is determined that the detection time of the uphill road S in the lower detection range BL has exceeded the set time T, the controller 26 determines that the obstacle detected in the lower detection range BL is an uphill road S. When it is determined that the obstacle detected in the lower detection range BL is an uphill road S, the controller 26 moves the front end of the first detection range A back to reduce the first detection range A. In this embodiment, the front end of the reduced first detection range A is located outside the second detection range B. If an obstacle is detected in the reduced first detection range A, the controller 26 brings the towing vehicle 10 to an abnormal stop. In other words, the reduced first detection range A corresponds to the detection range closest to the vehicle body 11, at which the towing vehicle 10 will be brought to an abnormal stop if an obstacle is detected in the first detection range A. The gradient of the uphill road S is limited to a gradient that does not cause interference between the reduced first detection range A and the uphill road S.

[0045] After reducing the first detection range A, the towing vehicle 10 continues autonomous driving and begins to climb the uphill road S, but the reduced first detection range A does not detect the road surface of the uphill road S. When the rear wheels 13 of the towing vehicle 10 roll on the road surface of the uphill road S, the towing vehicle 10 moves completely onto the uphill road S and no longer detects the road surface of the uphill road S in the lower detection range BL. When the road surface of the uphill road S is not detected in the lower detection range BL and no obstacle is detected in the lower detection range BL, the controller 26 returns the position of the front end of the first detection range A to the original position, thereby expanding the first detection range A. As a result, if there is an obstacle on the road surface of the uphill road S that is not detected in the lower detection range BL, the obstacle can be detected in the unreduced first detection range A, and the towing vehicle 10 can be decelerated and stopped.

[0046] In this embodiment, as the speed of the towing vehicle 10 increases, the lengths of the first detection range A and the second detection range B increase in the longitudinal direction, and as the speed decreases, the lengths of the first detection range A and the second detection range B decrease in the longitudinal direction. Therefore, the distance L varies depending on the speed of the towing vehicle 10. The range of the third detection range C does not vary regardless of the speed of the towing vehicle 10.

[0047] Furthermore, on an uneven road (not shown) with continuous unevenness in addition to the uphill road S, the second sensor 35 detects the uneven road in the lower detection zone BL of the second detection range B, just as on the uphill road S, and the controller 26 determines that it is an uneven road, so the uneven road will not be mistakenly detected as an obstacle. Also, when the towing vehicle 10 heads downhill onto a flat road surface, the flat road surface is detected in the lower detection zone BL of the second detection range B, and the controller 26 determines that it is a flat road surface, so the uneven road will not be mistakenly detected as an obstacle.

[0048] The towing vehicle 10 of this embodiment has the following advantages. (1) When the second sensor 35 detects an obstacle but the first sensor 34 does not, the controller 26 reduces the first detection range A. If the obstacle detected by the second sensor 35 is an uphill or uneven road, the first detection range A of the first sensor 34 is reduced, so that the first sensor 34 does not detect the uphill or uneven road, and the towing vehicle 10 can enter the uphill or uneven road without slowing down or stopping. Furthermore, if the controller 26 detects an obstacle within the reduced first detection range A after the second sensor 35 detects an obstacle, it can determine that the obstacle is not an uphill or uneven road. As a result, a towing vehicle 10 can be provided that does not require the location of the uphill or uneven road to be preset in the controller 26.

[0049] (2) When the detection time taken for the second sensor 35 to detect an obstacle exceeds a preset time T, the controller 26 reduces the first detection range A. Therefore, even if the vehicle body 11 momentarily tilts due to some cause such as vibration, the flat road surface F will not be judged as an uphill road or an uneven road.

[0050] (3) The lengths of the first detection range A and the second detection range B in the traveling direction are changed according to the traveling speed. Therefore, when the controller 26 decelerates or stops the towing vehicle 10 after detecting an obstacle with the first sensor 34 or the second sensor 35, the controller 26 can decelerate or stop the towing vehicle 10 so as not to interfere with the obstacle.

[0051] (4) The second detection range B is a two-dimensional area set in a direction intersecting the first detection range A, and therefore can detect obstacles that exist in a direction intersecting the first detection range A. Furthermore, the second detection range B is set inside the vehicle body 11 in the width direction of the vehicle body 11, and therefore can reliably detect uphill roads or uneven roads in the second detection range B, and obstacles that exist outside the vehicle body 11 in the width direction will not be detected, preventing unnecessary stops.

[0052] (5) The second detection range B is divided into a lower detection range BL and an upper detection range BT. When an obstacle is detected only in the lower detection range BL, the controller 26 reduces the first detection range A. When an obstacle is detected in the upper detection range BT, the controller 26 does not reduce the first detection range A. This allows the controller 26 to distinguish between an uphill or uneven road and an obstacle.

[0053] (6) When an obstacle is detected in the upper first detection zone BT1, the controller 26 determines that the detected obstacle is not an uphill or uneven road, and therefore decelerates the towing vehicle 10. As a result, the towing vehicle 10 can avoid collision with the obstacle.

[0054] (7) A third sensor 36 that detects obstacles is provided above the first sensor 34, and the third detection range C, which is the detection range of the third sensor 36, is set in a plane at a certain height from the first detection range A. Therefore, even if an obstacle exists above the first detection range A and out of the second detection range B, the third sensor 36 can detect the obstacle, and the controller 26 can avoid interference with the detected obstacle.

[0055] (Second embodiment) Next, a towing vehicle according to a second embodiment will be described. In this embodiment, the configuration of the second detection range in which the second sensor detects an obstacle differs from that of the first embodiment. In this embodiment, the same configuration as in the first embodiment will be referred to and the same reference numerals will be used.

[0056] 8, the towing vehicle 40 has a first sensor 34 and a second sensor 35 but does not have a third sensor 36. The controller 26 sets a second detection range B of the second sensor 35, which corresponds to the lower detection range BL in the first embodiment. The first detection range A and second detection range B of the first sensor 34 vary depending on the vehicle speed of the towing vehicle 40.

[0057] In this embodiment, if an uphill road S, for example, is present ahead of the autonomously traveling towing vehicle 40, the second sensor 35 detects the uphill road in the second detection range B. Specifically, the second sensor 35 detects the uphill road S in the second detection range B. Next, the controller 26 determines whether the detection time of the uphill road S in the second detection range B has exceeded the set time T. If it determines that the detection time of the uphill road S in the second detection range B has exceeded the set time T, the front end of the first detection range A is moved back to reduce the first detection range A. Note that FIG. 8 shows a state in which the front end of the first detection range A has been moved back to reduce the first detection range A.

[0058] Although the controller 26 cannot determine whether the obstacle detected in the second detection range B by the second sensor 35 is an uphill road S or an obstacle itself, the towing vehicle 40 can enter the uphill road S by continuing autonomous traveling. Incidentally, if the obstacle detected in the second detection range B by the second sensor 35 is an obstacle, it will be detected in the reduced first detection range A, allowing the towing vehicle 40 to stop without interfering with the obstacle.

[0059] As described above, in this embodiment, the controller 26 does not need to determine whether the obstacle detected by the second sensor 35 is an uphill road, an uneven road, or an obstacle itself. Note that, although the third sensor 36 is not provided in this embodiment, this is not limiting and the third sensor 36 may be provided. If the third sensor 36 is provided, when the third sensor 36 detects an obstacle in the third detection range C, the controller 26 does not reduce the first detection range A, but rather controls the travel drive device 20 to decelerate and stop the towing vehicle 10.

[0060] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the spirit of the invention. For example, the following modifications may be made.

[0061] In the above embodiment, an autonomously driven towing vehicle has been described as an example of an autonomously driven vehicle, but the autonomously driven vehicle is not limited to this. For example, the autonomously driven vehicle may be an autonomously driven forklift or an automated guided vehicle, or at least an autonomously driven industrial vehicle. In the above embodiment, the autonomous vehicle is a towing vehicle that can only travel forward, so the first detection range of the first sensor and the second detection range of the second sensor are set in front of the towing vehicle, but this is not limited to this. For example, if the autonomous vehicle can travel backward as well as forward, the first sensor and the second sensor may be provided at the rear of the autonomous vehicle so that the first detection range and the second detection range are also set behind the autonomous vehicle. In the above embodiment, the second sensor is a laser sensor capable of setting a two-dimensional detection range, but this is not limiting. The second sensor may be, for example, an ultrasonic sensor. As shown in FIG. 9 , in a modified example in which the second sensor 51 is an ultrasonic sensor, the second sensor 51 is installed at the center of the front of the vehicle body 11. The second detection range B of the second sensor 51 is linear. The front end of the second detection range B is located forward of the front end of the first detection range A when not reduced. The second detection range B is located lower than the first detection range A in the vertical direction, but may be at the same height as the first detection range A. Using an ultrasonic sensor can prevent a decrease in the detection accuracy of the second sensor due to fog or rain. In the above embodiment, the second sensors are provided on the left and right sides of the vehicle body, but this is not limiting. For example, a single second sensor may be provided on the vehicle body, and the number of second sensors is not particularly limited. In the above embodiment, the controller reduces the first detection range when the second sensor continues to detect an obstacle for a period of time exceeding a preset time. However, this is not limiting. For example, the controller may reduce the first detection range regardless of the length of time the second sensor detects an obstacle. In the above embodiment, the controller changes the lengths of the first and second detection ranges in the traveling direction in accordance with the traveling speed, but this is not limiting. For example, the lengths of the first and second detection ranges in the traveling direction may not be changed in accordance with the traveling speed. In the above embodiment, the autonomous vehicle automatically travels while creating an environmental map, but the present invention is not limited to this. For example, the autonomous vehicle may be a magnetically guided autonomous vehicle that travels automatically by being guided by a magnetic tape. [Explanation of symbols]

[0062] 10, 40 Towing vehicle (autonomous vehicle) 11 Body 12 Front wheels (steering wheels) 13 Rear wheels (drive wheels) 14 Driver's seat 20 Traveling drive unit 21 Steering gear 26 Controller 34 First Sensor 35, 51 Second sensor 36 Third Sensor 40 Towing vehicle (autonomous vehicle) A First detection range B Second detection range C. Third detection range BT Upper detection area BT1 Upper first detection zone BT2 Upper second detection area BL Lower detection area F Road surface (flat road) L distance S Uphill Road

Claims

1. The car body and a driving motor mounted on the vehicle body; a first sensor for detecting an obstacle in the traveling direction; a controller for controlling the driving motor, In an autonomous vehicle capable of autonomous travel, the controller controls the traction motor to decelerate or stop when the first sensor detects an obstacle, a second sensor for detecting an obstacle in the traveling direction; a first detection range, which is a detection range of the first sensor, is set in a plane at a certain height from the road surface and is shrinkable in the traveling direction; a second detection range that is a detection range of the second sensor is set below the first detection range, away from a road surface, in a traveling direction, and is set to be located inside the vehicle body in a width direction of the vehicle body, an end of the second detection range in the travel direction is located forward of an end of the first detection range when the image sensor is not reduced; The autonomous vehicle is characterized in that the controller reduces the first detection range when the second sensor detects an obstacle and the first sensor does not detect an obstacle.

2. 2. The autonomous vehicle according to claim 1, wherein the controller reduces the first detection range when the detection time taken for the second sensor to detect an obstacle exceeds a preset time.

3. 3. The autonomous vehicle according to claim 1, wherein the controller changes the lengths of the first detection range and the second detection range in the traveling direction in accordance with the traveling speed.

4. 3. The autonomous vehicle according to claim 1, wherein the second detection range is a two-dimensional area set in a direction intersecting the first detection range.

5. The second detection range is divided into a lower detection area and an upper detection area, 5. The autonomous vehicle according to claim 4, wherein the controller reduces the first detection range when an obstacle is detected only in the lower detection area, and does not reduce the first detection range when an obstacle is detected in the upper detection area.

6. the upper detection area is divided into an upper first detection area and an upper second detection area in the traveling direction, 6. The autonomous vehicle according to claim 5, wherein the controller decelerates the vehicle when an obstacle is detected in the upper first detection area.

7. a third sensor for detecting an obstacle is provided above the first sensor; a third detection range, which is a detection range of the third sensor, is set in a plane at a certain height from the first detection range, 3. The autonomous vehicle according to claim 1, wherein the controller decelerates when the third sensor detects an obstacle in the third detection range.

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