Autonomous vehicles

Abstract

To suppress contact between an object and an autonomous travel vehicle.SOLUTION: An autonomous travel vehicle comprises: a distance meter which measures a distance to a structural object in a non-contact manner; and a control device. The control device obtains the distance to the structural object, which exists in a search effective area, from the distance meter. The control device converts the distance to the structural object, which exists in the search effective area, into a distance in a vehicle width direction of the autonomous travel vehicle. The control device steers the autonomous travel vehicle so that a separation distance obtained based on the distance in the vehicle width direction becomes a predetermined distance. The search effective area is set so that a width of the search effective area of the structural object is wider than a width of a recessed portion of the structural object.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] This disclosure relates to autonomous vehicles. [Background technology]

[0002] The autonomous vehicle disclosed in Patent Document 1 comprises a plurality of contact sensors and an optical distance measuring sensor. The plurality of contact sensors are arranged in a line in the front-to-rear direction of the autonomous vehicle. The autonomous vehicle travels while the plurality of contact sensors are in contact with a wall. If a recess exists in the wall, the autonomous vehicle recognizes the shape of the wall from the distance measured by the optical distance measuring sensor. Then, in the area where a recess exists in the wall, the autonomous vehicle travels based on the distance measured by the optical distance measuring sensor. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-27020 [Overview of the project] [Problems that the invention aims to solve]

[0004] The autonomous vehicle disclosed in Patent Document 1 uses contact sensors to drive. In autonomous vehicles, there are cases where it is not possible to make contact with a wall using the contact sensors. For example, if there is an object along the wall, there is a risk that the object and the contact sensor may come into contact. [Means for solving the problem]

[0005] An autonomous vehicle that solves the above problems is an autonomous vehicle that travels along a structure at a predetermined distance from the structure, and comprises a distance meter that measures the distance to the structure non-contact, and a control device, wherein the control device obtains the distance to the structure located in a searchable area set based on the shape of the structure which has been known in advance from the distance meter, converts the distance to the structure located in the searchable area into a distance in the vehicle width direction of the autonomous vehicle, steers the autonomous vehicle so that the distance obtained based on the distance in the vehicle width direction becomes the predetermined distance, and the searchable area is set such that the width of the searchable area on the structure is wider than the width of the recess in the structure.

[0006] The control device converts the distance obtained from the rangefinder into a distance in the vehicle width direction. The control device steers the autonomous vehicle so that the distance between it and the target is a predetermined distance. The autonomous vehicle can be steered using a rangefinder that measures the distance to a structure without contact. Therefore, even if an object is present along a structure, contact between the object and the autonomous vehicle can be suppressed.

[0007] In the above-mentioned autonomous vehicle, the distance meter measures the distance to the structure located within a horizontally extending measurable range, and the search effective area may be a part of the measurable range.

[0008] With respect to the above-mentioned autonomous vehicle, the control device may use the shortest distance in the vehicle width direction as the separation distance. The above-mentioned autonomous vehicle is equipped with a self-position estimation device for estimating the autonomous vehicle's own position, and the control device may cause the autonomous vehicle to travel along the structure at a predetermined distance from the structure in a location where the self-position estimation device cannot perform the self-position estimation and which is a predetermined location. [Effects of the Invention]

[0009] According to the present invention, contact between an object and an autonomous vehicle can be suppressed.

Brief Description of the Drawings

[0010] [Figure 1] It is a schematic diagram of the area where the self-driving vehicle is used. [Figure 2] It is a schematic diagram of the tunnel existing in the area of FIG. 1. [Figure 3] It is a schematic configuration diagram of the self-driving vehicle of FIG. 1. [Figure 4] It is a flowchart showing the determination control executed by the control device of FIG. 3. [Figure 5] It is a flowchart showing the wall-following steering control executed by the control device of FIG. 3. [Figure 6] It is a diagram for explaining a method of deriving a search effective area used in the wall-following steering control of FIG. 5. [Figure 7] It is a schematic diagram showing a self-driving vehicle traveling inside the tunnel of FIG. 2. [Figure 8] It is a schematic diagram showing a self-driving vehicle traveling inside the tunnel of FIG. 2. [Figure 9] It is a schematic diagram showing a self-driving vehicle traveling inside the tunnel of FIG. 2. [Figure 10] It is a schematic diagram showing a self-driving vehicle traveling inside the tunnel of FIG. 2. [Figure 11] It is a flowchart showing the steering control executed by the control device of FIG. 3. [Figure 12] It is a schematic diagram showing a self-driving vehicle traveling inside a tunnel having a convex portion.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, an embodiment of the self-driving vehicle will be described. In the following description, front, rear, left, and right refer to the front, rear, left, and right when based on the self-driving vehicle. <Self-driving vehicle> As shown in Figure 1, the area in which the autonomous vehicle 10 is used includes a first point A1, a second point A2, and a tunnel T. The area is, for example, all or part of a place such as an airport, factory, port, commercial facility, and public facility. The tunnel T connects the first point A1 and the second point A2. The first point A1 and the second point A2 are locations where the autonomous vehicle 10 can receive satellite signals from GNSS (Global Navigation Satellite System) satellites. Inside the tunnel T, the autonomous vehicle 10 cannot receive satellite signals from GNSS satellites. The autonomous vehicle 10 is, for example, an industrial vehicle or a passenger car. An industrial vehicle is, for example, a towing tractor or a forklift.

[0012] As shown in Figure 2, a driving lane A3 and a stopping lane A4 are set up inside tunnel T. Driving lane A3 is where the autonomous vehicle 10 travels. Stopping lane A4 is where the autonomous vehicle 10 is stopped in the event of an abnormality. Tunnel T is provided with a wall W. The wall W is provided with a driving section W1 and a recess W2. Driving section W1 is provided along driving lane A3. Recess W2 is provided along stopping lane A4. Recess W2 is provided with a first section W3 and a second section W4. The first section W3 and the second section W4 are spaced apart and face each other in the direction in which driving section W1 extends. Driving section W1 is divided by recess W2. Recess W2 is the part that is recessed from driving section W1 toward the outside of tunnel T.

[0013] As shown in Figure 3, the autonomous vehicle 10 includes a control unit 11. The control unit 11 includes a processor 12 and a storage unit 13. Examples of the processor 12 include a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and a DSP (Digital Signal Processor). The storage unit 13 includes RAM (Random Access Memory) and ROM (Read Only Memory). The storage unit 13 stores program code or instructions configured to cause the processor 12 to execute processing. The storage unit 13, i.e., the computer-readable medium, includes any available medium that can be accessed by a general-purpose or dedicated computer. The control unit 11 may be composed of hardware circuits such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The control unit 11, which is a processing circuit, may include one or more processors that operate according to a computer program, one or more hardware circuits such as an ASIC or FPGA, or a combination thereof.

[0014] The autonomous vehicle 10 comprises drive wheels 21, a drive motor 22, a drive motor driver 23, and a rotation speed sensor 24. The drive motor 22 is a motor for rotating the drive wheels 21. The drive motor driver 23 drives the drive motor 22. The rotation speed sensor 24 detects the rotation speed of the drive motor 22. The autonomous vehicle 10 moves as the drive wheels 21 rotate due to the drive of the drive motor 22.

[0015] The autonomous vehicle 10 includes a steering wheel 31, a steering motor 32, a steering motor driver 33, and a steering sensor 34. The steering motor 32 is a motor for steering the steering wheel 31. The steering motor driver 33 drives the steering motor 32. The steering sensor 34 detects the rotational speed of the steering motor 32. The autonomous vehicle 10 turns when the steering wheel 31 is steered by the drive of the steering motor 32.

[0016] The autonomous vehicle 10 is equipped with a rangefinder 41. The rangefinder 41 measures the distance to an object non-contactually. The rangefinder 41 is, for example, a laser rangefinder, radar, or stereo camera. In this embodiment, the rangefinder 41 is a laser rangefinder. The rangefinder 41 emits laser light while changing the irradiation angle in the horizontal direction. The rangefinder 41 measures the distance to a point by receiving the reflected light reflected from the point where the laser light strikes. The point where the laser light strikes represents a part of the surface of an object. The position of the point can be expressed in polar coordinates. The coordinates of the point in polar coordinates may be converted to coordinates in Cartesian coordinates.

[0017] The autonomous vehicle 10 is equipped with a satellite navigation system 51. The satellite navigation system 51 receives satellite signals transmitted from GNSS satellites. The satellite navigation system 51 measures its position using the satellite signals.

[0018] The autonomous vehicle 10 is equipped with an auxiliary storage device 61. The auxiliary storage device 61 is a non-volatile storage device that can rewrite data. The auxiliary storage device 61 is, for example, a hard disk drive or a solid-state drive.

[0019] The auxiliary storage device 61 stores map data. The map data represents the structure of an area using coordinates in a map coordinate system. The map coordinate system may be a two-dimensional coordinate system or a three-dimensional coordinate system. The map coordinate system is a coordinate system with any point in the area where the autonomous vehicle 10 is used as its origin.

[0020] The control device 11 estimates the autonomous vehicle 10's own position. The autonomous vehicle's own position is the coordinate of a specific point on the map coordinate system. This point on the autonomous vehicle 10 can be arbitrary, but for example, it could be the vehicle's horizontal center position. The autonomous vehicle's own position may be estimated by comparing the measurement results of the distance meter 41 with map data. Alternatively, the autonomous vehicle's own position may be estimated using the position obtained by the satellite navigation system 51. The autonomous vehicle's own position may also be estimated by combining the estimation using the distance meter 41 with the estimation using the satellite navigation system 51. Furthermore, the autonomous vehicle's own position may be estimated by combining the above-described method with dead reckoning using internal sensors. Examples of internal sensors include the rotation speed sensor 24 and the steering sensor 34. The control device 11 is an example of a self-position estimation device. The autonomous vehicle 10 may be equipped with a self-position estimation device different from the control device 11.

[0021] The control device 11 causes the autonomous vehicle 10 to move by controlling the drive motor 22 and the steering motor 32. For example, the control device 11 generates a route to a target location. The control device 11 commands the drive motor driver 23 and the steering motor driver 33 to move the autonomous vehicle 10 along the route. As a result, the autonomous vehicle 10 moves.

[0022] <Decision Control> Next, the determination control performed by the control device 11 will be described. The determination control is a control that determines whether or not the autonomous vehicle 10 has entered the tunnel T.

[0023] As shown in Figure 4, in step S1, the control device 11 determines whether or not the autonomous vehicle 10 has entered tunnel T. The control device 11 determines whether or not the autonomous vehicle 10 has entered tunnel T based on its estimated position. By knowing the coordinates of tunnel T in the map coordinate system in advance, the control device 11 can recognize that the autonomous vehicle 10 has entered tunnel T when its position moves to the coordinates of tunnel T. If there are multiple tunnels T in the area, the control device 11 can also determine which of the multiple tunnels T the autonomous vehicle 10 has entered. If the result of the determination in step S1 is negative, the control device 11 terminates the determination control. If the result of the determination in step S1 is positive, the control device 11 performs the processing in step S2.

[0024] In step S2, the control device 11 performs wall-following steering control. Wall-following steering control is steering control performed inside tunnel T. Inside tunnel T, self-position estimation is not possible due to the following factors. Note that the situation of "self-position estimation not being possible" also includes situations where, even if self-position estimation is possible, the accuracy of self-position estimation is low, which hinders the practical use of the autonomous vehicle 10.

[0025] Within tunnel T, there are few objects that can serve as landmarks, making it difficult to estimate one's own position using the rangefinder 41. Within tunnel T, it is difficult to receive satellite signals, making it difficult to estimate one's own position using the satellite navigation device 51. Furthermore, when creating map data, it is difficult to generate map data if the position obtained by the satellite navigation device 51 is used. In dead reckoning, the deviation of one's own position accumulates, making it difficult to estimate one's own position.

[0026] The control device 11 controls the autonomous vehicle 10 so that its estimated self-position aligns with the path at the first point A1 and the second point A2, which are outside the tunnel T. Inside the tunnel T, the control device 11 controls the autonomous vehicle 10 by steering along the wall. The tunnel T is an example of a pre-set location where self-position estimation is not possible.

[0027] <Wall-following steering control> The wall-following steering control performed by the control device 11 will now be described. Wall-following steering control is a control method that causes the autonomous vehicle 10 to travel along a wall W. The control device 11 causes the autonomous vehicle 10 to travel along the wall W while it is at a predetermined distance from the wall W. The wall W is an example of a structure. The predetermined distance can be set arbitrarily. For example, the predetermined distance is set so that the autonomous vehicle 10 travels in travel lane A3.

[0028] As shown in Figure 5, in step S10, the control device 11 reads a set value. The set value is a value necessary for performing wall-side steering control. The set value includes a target value D1 from the autonomous vehicle 10 to the wall W, i.e., a target value D1 for a predetermined distance. The set value may also include the width W11 of the recess W2. The width W11 of the recess W2 is the dimension between the first part W3 and the second part W4. If the tunnel T has multiple recesses W2 with different widths W11, the set value for the width W11 of the recess W2 should be the longest of the widths W11 of the recesses W2. If the width W11 of the recess W2 is not constant between the first part W3 and the second part W4, the width W11 of the recess W2 may be the width at the position closest to the travel zone A3. If there are multiple tunnels T in the area, the set value may differ for each tunnel T. In this case, the set value corresponding to the tunnel T into which the autonomous vehicle 10 entered should be read. The setting value may be stored in the memory unit 13 or in the auxiliary storage device 61.

[0029] As shown in Figures 5 and 6, in step S11, the control device 11 then determines the effective search area A12. The effective search area A12 is a portion of the measurable range A11 in which the distance can be measured by the distance meter 41. The effective search area A12 is predetermined. If there are multiple tunnels T in the area, the effective search area A12 may be different for each tunnel T. In this case, it is sufficient to determine the effective search area A12 corresponding to the tunnel T into which the autonomous vehicle 10 entered.

[0030] This section explains how to derive the searchable area A12. As shown in Figure 6, the measurable range A11 is a range that extends horizontally. The measurable range A11 is a sector-shaped range of a predetermined angle to the left and right of the reference axis RA that extends in the forward direction of the autonomous vehicle 10. The predetermined angle is, for example, 135°. In this case, the measurable range A11 is a sector-shaped range of 270° with respect to the horizontal direction. When the autonomous vehicle 10 is driven along the left wall W, the effective search area A12 is set from the range to the left of the reference axis RA. When the autonomous vehicle 10 is driven along the right wall W, the effective search area A12 is set from the range to the right of the reference axis RA. In this embodiment, since the effective search area A12 is set from the range to the left of the reference axis RA, Figure 6 shows only the range to the left of the reference axis RA within the measurable range A11.

[0031] The distance meter 41 measures distance within the measurable range A11 according to the angular resolution with respect to the horizontal. The distance meter 41 measures the distance to the point where the scan line L intersects with the object. The scan line L represents the point where distance is measured according to the angular resolution. If the distance meter 41 is a laser distance meter, the scan line L is the trajectory of the laser beam. The length of the scan line L is the reachable distance of the laser beam. Therefore, the radius of the measurable range A11 is the reachable distance of the laser beam.

[0032] The searchable area A12 is the first scan line L A and the second scan line L B It is within the range between. First scan line L A This is the scan line L that marks the start of the search effective area A12 among the multiple scan lines L. Second scan line L B This is the scan line L that marks the end of the search effective area A12 among the multiple scan lines L. First scan line L A and the second scan line L B This can be determined from the target value D1 to the wall W and the width W11 of the recess W2. In Figure 6, for illustrative purposes, the width W11 of the recess W2 is shown to be longer than in Figure 2.

[0033] First scan line L Acan be obtained from the target value D1 to the wall W. The dimension of the scanning line L can be converted into a distance in the Y-axis direction. The distance in the Y-axis direction is the coordinate of the Y-axis when the measurement result of the distance meter 41 is represented in a rectangular coordinate system. The rectangular coordinate system is a coordinate system in which the reference axis RA in the horizontal direction is taken as the X-axis, and the axis orthogonal to the X-axis in the horizontal direction is taken as the Y-axis. The origin of the rectangular coordinate system is the position where the distance meter 41 is arranged.

[0034] Let the dimension of each scanning line L be R i and the angle between each scanning line L and the reference axis RA be the scanning line angle θ i Then, the distance in the Y-axis direction of each scanning line L can be obtained by R i × sinθ i The first scanning line L A is the scanning line L where the distance in the Y-axis direction first exceeds the target value D1 when measuring the distance in order according to the angular resolution from the reference axis RA. The first scanning line L A is the scanning line L at the angle where the laser light first reaches the wall W when irradiating the laser light in order from the reference axis RA.

[0035] Let the point where the distance in the Y-axis direction becomes the target value D1 on the first scanning line L A be the starting point A. The starting point A is the point where it is assumed that the first scanning line L A hits the traveling part W1 when the autonomous driving vehicle 10 travels along the wall W. If the coordinates of the starting point A in the rectangular coordinate system are represented by (X, Y), they are (D1 / tanθ A , D1). The angle θ A is the scanning line angle θ A of the first scanning line L i .

[0036] In the X-axis direction, in the direction toward the rear of the autonomous driving vehicle 10, let the point separated from the starting point A by the width W11 of the recess W2 be the end point B. The coordinates of the end point B in the rectangular coordinate system are ((D1 / tanθ A ) - W11, D1). The angle θ B is the angle formed by the virtual line segment connecting the origin and the end point B and the reference axis RA. The angle θ B can be obtained by the following formula (1).

[0037]

number

[0038] The search area A12 defined as described above is set so that when the autonomous vehicle 10 is traveling along the wall W, the entire width W11 of the recess W2 is contained within the search area A12. More specifically, the search area A12 is set so that its width on the wall W is wider than the width W11 of the recess W2 on the wall W. The width of the search area A12 on the wall W is the width of the first scan line L A The point where it intersects with wall W and the second scan line L B This is the dimension in the X-axis direction between the point where the wall W intersects with the meter. If the distance meter 41 is a laser distance meter, when the laser beam is irradiated onto the wall W, the width of the range of the laser beam irradiated onto the wall W is the width of the effective search area A12 on the wall W. Since the target value D1 is the distance between the autonomous vehicle 10 and the wall W, by making the dimension in the X-axis direction of the effective search area A12 at the position where the Y coordinate is the target value D1 larger than the width W11 of the recess W2, the width of the effective search area A12 on the wall W becomes wider than the width W11 of the recess W2 on the wall W. Therefore, when the autonomous vehicle 10 is traveling along the wall W, at least one of the scan lines L included in the effective search area A12 is set to hit the traveling part W1. More specifically, when the autonomous vehicle 10 is traveling along the wall W, the first scan line L A and the second scan line L BAt least one of these corresponds to the driving section W1, regardless of the positional relationship between the autonomous vehicle 10 and the recess W2. As used herein, the expression "at least one" means "one or more" of the desired options. For example, as used herein, the expression "at least one" means "only one option" or "both of the two options" if there are two options. As another example, as used herein, the expression "at least one" means "only one option" or "a combination of two or more arbitrary options" if there are three or more options.

[0039] The searchable area A12 derived as described above may be stored in the memory unit 13 or in the auxiliary memory device 61. As described above, the searchable area A12 is set based on the shape of the wall W which has been determined in advance.

[0040] As shown in Figure 5, in step S12, the control device 11 then acquires the measurement result from the distance meter 41. Next, in step S13, the control device 11 obtains the shortest distance in the Y-axis direction within the search effective area A12 from the measurement results acquired in step S12. A detailed explanation follows below.

[0041] As shown in Figure 7, the control device 11 converts each distance measured within the search effective area A12 into a Y-axis distance Y1. The Y-axis distance Y1 is the distance in the vehicle width direction of the autonomous vehicle 10. The Y-axis distance Y1 is calculated using the distance measured by the distance meter 41 and the scan line angle θ, similar to how the Y-axis distance of the scan line L is calculated. i It can be calculated using the formula.

[0042] The control device 11 obtains the shortest distance among the calculated Y-axis distances Y1. The control device 11 considers the shortest distance among the Y-axis distances Y1 to be the separation distance. The separation distance is the distance between the autonomous vehicle 10 and the wall W. As can be seen from Figure 7, when the laser beam enters the stopping zone A4, which is the area surrounded by the recess W2, that is, when the distance meter 41 is measuring the distance to the recess W2, the Y-axis distance Y1 is longer than when the distance to the driving unit W1 is being measured. In addition, the search effective area A12 is set so that at least one of the scan lines L included in the search effective area A12 hits the driving unit W1. For this reason, the shortest distance among the Y-axis distances Y1 represents the Y-axis distance Y1 from the autonomous vehicle 10 to the driving unit W1.

[0043] As shown in Figure 8, before the autonomous vehicle 10 reaches the recess W2, the shortest distance in the Y-axis direction Y1 is the distance in the Y-axis direction Y1 to the driving section W1 located behind the recess W2.

[0044] As shown in Figure 9, when the autonomous vehicle 10 is approaching the recess W2, the shortest distance in the Y-axis direction Y1 is the distance in the Y-axis direction Y1 to the driving section W1 which is located ahead of the recess W2.

[0045] As shown in Figure 10, even when the autonomous vehicle 10 is traveling in a position facing the recess W2, the shortest distance in the Y-axis direction Y1 is the distance in the Y-axis direction Y1 to the driving section W1 which is located in front of the recess W2.

[0046] Next, in step S14, the control device 11 performs steering control. Next, in step S15, the control device 11 determines whether the autonomous vehicle 10 has left the tunnel T. The control device 11 may determine that the autonomous vehicle 10 has left the tunnel T if, for example, the satellite navigation device 51 receives a satellite signal. If the determination result in step S15 is positive, the control device 11 terminates the wall-following steering control. If the determination result in step S15 is negative, the control device 11 returns to step S12.

[0047] <Steering control> The steering control performed by the control device 11 will now be described. The steering control is a control that steers the autonomous vehicle 10 so that it travels along the wall W while maintaining a predetermined distance from the wall W.

[0048] As shown in Figure 11, in step S20, the control device 11 determines whether the shortest distance in the Y-axis direction Y1 is equal to the target value D1. If the determination result in step S20 is positive, the control device 11 performs the process in step S21. If the determination result in step S20 is negative, the control device 11 performs the process in step S22.

[0049] In step S21, the control device 11 maintains the current steering. In step S22, the control device 11 determines whether the shortest distance Y1 in the Y-axis direction is greater than the target value D1. If the determination result in step S22 is positive, the control device 11 performs the process in step S23. If the determination result in step S22 is negative, the control device 11 performs the process in step S24.

[0050] In step S23, the control device 11 steers the autonomous vehicle 10 so that it approaches the wall W. For example, the control device 11 controls the steering motor 32 so that the autonomous vehicle 10 approaches the wall W by giving a command to the steering motor driver 33.

[0051] In step S24, the control device 11 steers the autonomous vehicle 10 so that it moves away from the wall W. For example, the control device 11 controls the steering motor 32 so that the autonomous vehicle 10 moves away from the wall W by giving a command to the steering motor driver 33.

[0052] As described above, by performing steering control, the autonomous vehicle 10 travels along the wall W while maintaining a predetermined distance from the wall W. [Operation of this embodiment] The control device 11 performs wall-following steering control when the autonomous vehicle 10 enters tunnel T. The control device 11 converts the distance to the wall W in the searchable area A12 into a Y-axis distance Y1. The control device 11 controls the autonomous vehicle 10 so that the shortest distance in the Y-axis distance Y1 becomes the target value D1. The shortest distance in the Y-axis distance Y1 is the distance from the autonomous vehicle 10 to the driving unit W1, regardless of the positional relationship between the autonomous vehicle 10 and the recess W2. Therefore, when the autonomous vehicle 10 is controlled so that the shortest distance in the Y-axis distance Y1 becomes the target value D1, the autonomous vehicle 10 will be steered so that the distance from the driving unit W1 to the autonomous vehicle 10 becomes the target value D1. Even when a stopping zone A4 is provided, such as in tunnel T, the autonomous vehicle 10 is prevented from entering the stopping zone A4. That is, even when a stopping zone A4 exists, the autonomous vehicle 10 maintains its movement in the driving zone A3.

[0053] As shown in Figure 12, suppose that the wall W has a protrusion W5 that projects into the tunnel T. In this case, as the autonomous vehicle 10 approaches the protrusion W5, the shortest distance in the Y-axis direction Y1 becomes shorter. The autonomous vehicle 10 will travel so that the shortest distance in the Y-axis direction Y1 becomes the target value D1, and will be controlled to move away from the protrusion W5. As a result, the autonomous vehicle 10 will steer to avoid the protrusion W5. Therefore, even if the wall W has a protrusion W5, the autonomous vehicle 10 can continue to travel.

[0054] [Effects of this embodiment] (1) The control device 11 converts the distance acquired from the distance meter 41 into a distance Y1 in the Y-axis direction. The control device 11 steers the autonomous vehicle 10 so that the distance between the vehicle and the distance acquired based on the distance Y1 in the Y-axis direction becomes a predetermined distance. The autonomous vehicle 10 can be steered using the distance meter 41, which measures the distance to the wall W without contact. Therefore, even if there is an object along the wall W, contact between the object and the autonomous vehicle 10 can be suppressed. For example, if a walking path is set up along the wall W, there may be people or other objects in the walking path. In such a case, if the contact sensor is brought into contact with the wall W, there is a risk that these objects will come into contact with the contact sensor. In contrast, with the autonomous vehicle 10 of this embodiment, contact between the object and the autonomous vehicle 10 can be suppressed.

[0055] (2) The control device 11 obtains the distance to the wall W located in the search area A12. The search area A12 is set such that the width of the search area A12 at the wall W is wider than the width W11 of the recess W2. Therefore, the distance Y1 in the Y-axis direction includes the distance to the driving unit W1. This makes it possible to prevent the autonomous vehicle 10 from entering a place where it might enter, such as a stopping zone A4.

[0056] (3) The control device 11 uses the shortest distance in the Y-axis direction Y1 as the separation distance. The shortest distance in the Y-axis direction Y1 is the distance to the driving unit W1. Therefore, it is easy to maintain a constant distance in the Y-axis direction Y1 between the driving unit W1 and the autonomous driving vehicle 10.

[0057] (4) The control device 11 performs wall-following steering control in a predetermined location where it is not possible to estimate its own position. This allows the autonomous vehicle 10 to travel even in locations where it is not possible to estimate its own position.

[0058] [Example of changes] The embodiment can be implemented with the following modifications. The embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0059] ○The control device 11 may use the average value of the Y-axis distance Y1 to the wall W in the search area A12 as the separation distance. In this case, the control device 11 may use the average value of a predetermined number of Y-axis distances Y1, including the shortest distance, as the separation distance. For example, if the predetermined number is 3, the control device 11 may use the average value of the shortest distance, the second shortest distance, and the third shortest distance of the Y-axis distance Y1 as the separation distance. The predetermined number can be set arbitrarily. The control device 11 steers the autonomous vehicle 10 so that the separation distance becomes the target value D1.

[0060] ○The control device 11 does not need to estimate its own position. In this case, the control device 11 may control the autonomous vehicle 10 solely by wall-following steering control. ○The distance meter 41 may measure distance in one direction. In this case, the autonomous vehicle 10 is equipped with at least two distance meters 41. One distance meter 41 measures the first scan line L A It is positioned to measure the distance to the second scanning line L. One distance meter 41 is positioned to measure the distance to the second scanning line L. B They are positioned to measure the distance between them. The area between these two distance meters 41 is the search area A12.

[0061] ○Second scan line L B The scan line angle θ is i angle θ B Any scan line L that is larger will suffice. ○The structure only needs to be installed in the area where the autonomous vehicle 10 travels. For example, the structure may be a guardrail.

[0062] ○A distance meter 41 may be used that measures distance including the vertical component according to the angular resolution with respect to the vertical direction. In this case, the control device 11 may calculate the Y-axis distance Y1 using the distance measured by a scan line L located at the same height as the distance meter 41, which can be obtained from the distance meter 41. That is, if the axis perpendicular to the X and Y axes in the Cartesian coordinate system representing the measurement results of the distance meter 41 is defined as the Z axis, the Y-axis distance Y1 may be calculated from the distance where the Z coordinate is the same as that of the distance meter 41. Furthermore, the Y-axis distance Y1 can be calculated from the distance including the vertical component. For this reason, the control device 11 may calculate the Y-axis distance Y1 using the distance measured by a scan line L located at a different height from the distance meter 41, which can be obtained from the distance meter 41. [Explanation of Symbols]

[0063] A11... Measurable range, A12... Search effective area, W... Wall (a structure), W2... Recess, 10... Autonomous vehicle, 11... Control device (a self-position estimation device), 41... Distance meter.

Claims

1. An autonomous vehicle that travels along a structure while maintaining a predetermined distance from the structure, A distance meter for non-contact measurement of the distance to the aforementioned structure, A control device is provided, The control device is Based on the shape of the structure which has been determined in advance, the effective search area is set up, and the distance to the structure located within the effective search area, which is a part of the measurable range in which the distance can be measured by the distance meter, is obtained from the distance meter. The distance to the structure located within the search area is converted into the distance in the vehicle width direction of the autonomous vehicle. The autonomous vehicle is steered so that the distance between vehicles, obtained based on the distance in the vehicle width direction, becomes the predetermined distance. An autonomous vehicle wherein the effective search area is set such that the width of the effective search area in the structure is wider than the width of the recess in the structure.

2. The autonomous vehicle according to claim 1, wherein the distance meter measures the distance to the structure located within the horizontally extending measurable range.

3. The autonomous vehicle according to claim 1 or 2, wherein the control device uses the shortest distance in the vehicle width direction as the separation distance.

4. The autonomous vehicle is equipped with a self-position estimation device for estimating its own position, The autonomous vehicle according to claim 1 or 2, wherein the control device causes the autonomous vehicle to travel along the structure at a predetermined distance from the structure in a location where the self-position estimation device cannot estimate its own position and which is a predetermined location.

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