Autonomous driving device and control method for the autonomous driving device

Abstract

An autonomous traveling device according to one embodiment of the present invention comprises a recognition unit that recognizes obstacles for each of left and right regions sandwiching the body of the autonomous traveling device, a direction calculation unit that calculates a direction along the obstacles for each of the left and right regions, and a deviation control unit that causes the body to move away from the obstacles by combining a pivot movement, which is a movement for changing the orientation of the body toward an intermediate direction between the directions calculated by the direction calculation unit, with a backward movement for causing the body to move backward.

Description

Technical Field

[0001] The present invention relates to an autonomous driving device and a control method for an autonomous driving device. This application claims priority based on Japanese Patent Application No. 2021-150062 filed in Japan on September 15, 2021, the content of which is incorporated herein by reference.

Background Art

[0002] Conventionally, an autonomous driving device that autonomously travels to a destination based on map information or the like is known. In addition to being used in factories where the entry and exit of ordinary people are not assumed, the autonomous driving device has also been proposed for use in homes and public places.

[0003] The autonomous driving device is prohibited from traveling near obstacles preset on a map or detected by sensors. Therefore, the autonomous driving device calculates a route to avoid the prohibited driving area and waits for the movement of the obstacle when an obstacle such as a falling object or a person is suddenly detected. However, if the obstacle does not move, the vehicle cannot move only by waiting, so a recovery operation to move away from the obstacle to a position where autonomous driving is possible is required.

[0004] For example, in Patent Document 1, when an emergency obstacle is identified, a driving control method is proposed in which the transport vehicle is reversed to the nearest grid point and an avoidance operation is performed at a position where it does not collide with the obstacle.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, with a recovery operation that only involves reversing, there is a risk that recovery may become impossible or that the time and distance required for recovery may be long, depending on the positional relationship with obstacles and the surrounding environment, such as curves in the path. Therefore, the present invention aims to enable a rapid return to autonomous driving. Here, "rapid" means short in at least one of time and distance. [Means for solving the problem]

[0007] One embodiment of the autonomous driving device according to the present invention includes: a confirmation unit that checks for obstacles in each of the left and right regions flanking the main body of the autonomous driving device; a direction calculation unit that calculates a direction along the obstacle for each of the left and right regions; and a separation control unit that combines a rotational movement that changes the orientation of the main body toward the intermediate direction of each direction calculated by the direction calculation unit and a reverse movement that moves the main body backward to move the main body away from the obstacle.

[0008] Furthermore, the control method for the autonomous driving device according to the present invention includes a confirmation process for checking for obstacles in each of the left and right regions surrounding the main body of the autonomous driving device, a direction calculation process for calculating the direction along the obstacle for each of the left and right regions, and a separation control process that combines a rotational movement to change the orientation of the main body toward the intermediate direction between each of the directions calculated by the direction calculation unit and a reverse movement to move the main body backward, thereby moving the main body away from the obstacle. [Effects of the Invention]

[0009] According to the present invention, a rapid return to autonomous driving is achieved. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a side view showing the external appearance of the autonomous driving device of this embodiment. [Figure 2] Figure 2 is a front view showing the external appearance of the autonomous driving device of this embodiment. [Figure 3] Figure 3 is a top view showing the external appearance of the autonomous driving device of this embodiment. [Figure 4]Figure 4 is a functional block diagram showing the functional configuration of the autonomous driving device of this embodiment. [Figure 5] Figure 5 shows the measurement range in the autonomous driving device. [Figure 6] Figure 6 shows an example of map information stored in the memory unit. [Figure 7] Figure 7 is a flowchart showing the autonomous driving operation process in an autonomous driving device. [Figure 8] Figure 8 shows a state where autonomous driving is impossible and recovery is required. [Figure 9] Figure 9 shows a recovery movement using linear reverse motion. [Figure 10] Figure 10 shows a diagram illustrating recovery through turning. [Figure 11] Figure 11 is a flowchart showing the processing steps involved in the obstacle detection process. [Figure 12] Figure 12 shows an example of recovery through turning. [Figure 13] Figure 13 shows an example of recovery near a linear obstacle. [Figure 14] Figure 14 shows the recovery process when no obstacles are found in the left-hand region. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments of the autonomous driving device and the control method for the autonomous driving device of this disclosure will be described in detail with reference to the attached drawings. However, in order to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art, more detailed explanations than necessary may be omitted. For example, detailed explanations of already well-known matters and redundant explanations of substantially identical configurations may be omitted. Also, elements described in the previously described drawings may be referred to as appropriate in the later descriptions of the drawings. Figures 1 to 3 show the external appearance of the autonomous driving device of this embodiment. Figure 1 shows a side view, Figure 2 shows a front view, and Figure 3 shows a top view.

[0012] The autonomous driving device 100 of this embodiment is a device called an AMR (Autonomous Mobile Robot) that transports materials, etc. in, for example, factories or public places. The autonomous driving device 100 includes a main body 101, a loading platform 102, wheels 103, casters 104, a front sensor 105, and a rear sensor 106.

[0013] The main body 101 incorporates a control computer, a driving power source, etc. The shape of the main body 101 when viewed from above and below is a rectangular shape. The "rectangular shape" includes a rectangle, a shape with rounded corners of a rectangle, and a shape with rounded corners of a rectangle. In the following description, the position of the front sensor 105 is shown as a landmark before and after the autonomous driving device 100.

[0014] Loads such as materials are loaded on the loading platform 102. The size of the load may exceed the size of the loading platform 102 or the main body 101, but in the following, for the sake of convenience of explanation, the case where the load fits within the size of the loading platform 102 is taken as an example.

[0015] As an example, the wheels 103 are provided at two locations on the left and right of the main body 101 and are rotationally driven by a motor inside the main body 101. The left and right wheels 103 can be driven independently, and the autonomous driving device 100 can move forward, backward, rotate in place, and turn (a movement that draws a so-called curve) by driving the left and right wheels 103.

[0016] As an example, the casters 104 are provided at each of the four corners of the main body 101 to support the main body 101 so that it does not tilt. The casters 104 do not have a driving force, roll according to the movement of the main body 101, and the direction also changes according to the movement of the main body 101. The front sensor 105 detects obstacles, etc. in a wide range in front of and to the left and right of the main body 101. For example, a 2D-LiDER is used as the front sensor 105.

[0017] The rear sensor 106 detects obstacles and other objects behind the main unit 101. For example, an infrared sensor is used as the rear sensor 106, and detection is performed by multiple sensor elements installed along the rear outer surface of the main unit 101. Figure 4 is a functional block diagram showing the functional configuration of the autonomous driving device 100 of this embodiment. The autonomous driving device 100 comprises a control unit 110, a storage unit 120, a drive unit 130, and a measurement unit 140. The control unit 110 is a function performed by a computer built into the main unit 101 and controls the entire autonomous driving device 100. The storage unit 120 stores map information of the area in which the autonomous driving device 100 travels and the route traveled within that area.

[0018] The drive unit 130 is a function performed by a power supply and motor built into the main body 101 and the wheel 103. The autonomous driving device 100 moves when the drive unit 130 is driven according to the control of the control unit 110. The measurement unit 140 is a function performed by the front sensor 105 and rear sensor 106. The control unit 110 includes a path search unit 111, a path driving unit 112, and an obstacle response unit 113.

[0019] The route search unit 111 searches for and determines a route to the destination based on the map information stored in the memory unit 120, and stores the determined route in the memory unit 120. In this embodiment, the route search unit 111 searches for a route that can reach the destination without reversing while avoiding obstacles shown in the map information, and determines the shortest route to the destination. The route driving unit 112 controls the drive unit 130 so that the autonomous driving device 100 drives along the route stored in the memory unit 120.

[0020] The obstacle response unit 113 responds to obstacles detected by the measurement unit 140. While driving under the control of the route driving unit 112, the autonomous driving device 100 does not reverse, and the obstacle response unit 113 confirms safety using the measurement unit 140. The obstacle response unit 113 may correct the direction of travel to avoid getting too close to detected obstacles. If an obstacle not shown in the map information, such as a fallen object or an approaching person, is suddenly detected at close range, the obstacle response unit 113 controls the drive unit 130 to cause the autonomous driving device 100 to go into standby or return to normal. Details of the obstacle response unit 113 will be explained later. Figure 5 shows the measurement range of the autonomous driving device 100.

[0021] As described above, the autonomous driving device 100 is equipped with, for example, a 2D-LiDAR as a forward sensor 105, and the measurement range 210 of the forward sensor 105 has a field of view of 270° and a positioning distance of 30m. The forward sensor 105 can measure the direction and distance of objects (i.e., obstacles) within the measurement range 210.

[0022] Furthermore, the autonomous driving device 100 is equipped with, for example, an infrared sensor as a rear sensor 106, and the measurement range 220 of the rear sensor 106 has a positioning distance of approximately 0.2 to 1 m. The rear sensor 106 can detect the presence or absence of objects (i.e., obstacles) within the measurement range 220. Figure 6 shows an example of map information stored in the memory unit 120.

[0023] The map information 121 represents the autonomous driving area of ​​the autonomous driving device 100 as a set of unit sections 122 divided into a grid. Each unit section 122 is assigned, for example, three types of information. That is, a unit section 122_2 containing an object is assigned, for example, the value "100", a unit section 122_1 containing nothing is assigned, for example, the value "0", and an unknown unit section 122_3 is assigned, for example, the value "-1". Based on this map information 121, the autonomous driving device 100 searches for and determines a driving route and autonomously drives along the determined route. Figure 7 is a flowchart showing the autonomous driving operation process in the autonomous driving device 100.

[0024] When autonomous driving begins, the autonomous driving device 100 uses the route search unit 111 of the control unit 110 to search for and determine a driving route from its current location to its destination (step S101). The route search unit 111 may, for example, periodically repeat the route search during autonomous driving of the autonomous driving device 100, but for the sake of explanation below, it is assumed that the route is searched and determined at the beginning, and then the device drives along the determined route thereafter.

[0025] After step S101, the autonomous driving device 100 performs the initial movement operation under the control of the drive unit 130 by the path driving unit 112 of the control unit 110. Specifically, it first rotates in place (step S102), and during the rotation, the obstacle response unit 113 performs an obstacle check (step S103). If the angle difference between the orientation of the autonomous driving device 100 and the path is not within an acceptable range (step S104: NO), it returns to step S102 and continues rotating in place.

[0026] If the angle difference between the orientation of the autonomous driving device 100 and the path is within an acceptable range (Step S104: YES), the autonomous driving device 100 performs a motion operation controlled by the path driving unit 112 of the control unit 110, which controls the drive unit 130. During the motion operation, the device travels along the path (Step S105), and while traveling, the obstacle response unit 113 performs an obstacle check (Step S106). If the distance between the autonomous driving device 100 and the destination is not within the vehicle radius (Step S107: NO), the process returns to Step S105 and continues traveling.

[0027] When the distance between the autonomous driving device 100 and the destination reaches within the vehicle radius (step S107: YES), the autonomous driving device 100 performs the operation at the end of movement, controlled by the drive unit 130 via the path driving unit 112 of the control unit 110. Specifically, first it rotates in place (step S108), and during the rotation... The obstacle detection unit 113 performs an obstacle check (step S109). If the angle difference between the orientation of the autonomous driving device 100 and the direction of the destination is not within the allowable value (step S110: NO), the process returns to step S108 and continues to rotate in place.

[0028] If the angle difference between the orientation of the autonomous driving device 100 and the direction of the destination is within an acceptable range (step S110: YES), the autonomous driving device 100 starts moving forward (step S111), and while moving forward, the obstacle detection unit 113 performs an obstacle check (step S112). If the distance between the autonomous driving device 100 and the destination is not within an acceptable range (step S113: NO), the process returns to step S111 and continues moving forward.

[0029] If the distance between the autonomous driving device 100 and the destination reaches within the allowable error (step S113: YES), the autonomous driving device 100 rotates in place (step S114), and during the rotation, the obstacle response unit 113 performs an obstacle check (step S115). If the angle difference between the orientation of the autonomous driving device 100 and the orientation when it stops at the destination is not within the allowable value (step S116: NO), the process returns to step S114 and continues rotating in place. If the angle difference between the orientation of the autonomous driving device 100 and the orientation when it stops at the destination reaches within the allowable value (step S116: YES), the autonomous driving device 100 terminates its autonomous driving operation.

[0030] In the obstacle check process in steps S103, S106, S109, S112, and S115, if there are no obstacles, the operation of the autonomous driving device 100 simply continues. If an obstacle is present, a recovery operation is performed to move away from the obstacle, and the process returns to step S101. The concept of the operation in recovery is explained below.

[0031] Figures 8 to 10 illustrate the concept of recovery operation. Figure 8 shows a state where autonomous driving is impossible and recovery is required, Figure 9 shows recovery by moving backward in a straight line, and Figure 10 shows recovery by turning.

[0032] The autonomous driving device 100 searches for a route that avoids the no-travel zone 320 within a set distance A from the obstacle 310 and drives accordingly. However, if the obstacle 310 is a fallen object, the autonomous driving device 100 may enter the no-travel zone 320. For ease of calculation, the position of the autonomous driving device 100 is set to the center 100a of the vehicle body.

[0033] If the vehicle's center 100a enters the no-travel zone 320, the autonomous driving device 100 becomes unable to perform normal autonomous driving along its travel path. Therefore, the autonomous driving device 100 stops and waits for the obstacle 310 to disappear. If the obstacle 310 does not disappear after waiting, the autonomous driving device 100 performs a recovery operation to move away from the obstacle 310 and exit the no-travel zone 320.

[0034] As shown in Figure 9, the autonomous driving device 100 can exit the restricted area 320 by recovering by moving in a straight line backward, and after exiting the restricted area 320, the autonomous driving device 100 can resume autonomous driving. However, depending on the positional relationship with the obstacle 310, the recovery by the autonomous driving device 100 by moving in a straight line backward may require, for example, moving backward along the obstacle 310 for a long distance (or for a long time).

[0035] In contrast, as shown in Figure 10, the autonomous driving device 100 can quickly exit the restricted area 320 by performing a turning recovery. Here, "quickly" means short in at least one of time and distance. Thus, since recovery by turning is superior to recovery by straight reverse movement, recovery by turning is employed in the autonomous driving device 100 of this embodiment. Figure 11 is a flowchart showing the processing content in the obstacle check process.

[0036] In the obstacle check process, first, the measurement unit 140 controlled by the obstacle response unit 113 measures objects around the autonomous driving device 100, and it is determined whether there are any obstacles within the set distance A described above (i.e., whether the autonomous driving device 100 has entered the no-travel zone 320) (step S201). If there are no obstacles within the set distance A (step S201: NO), autonomous driving continues.

[0037] On the other hand, if an obstacle exists within the set distance A (step S201: YES), the drive unit 130 is controlled by the obstacle response unit 113, and the autonomous driving device 100 stops and waits for a short time (step S202). If the cumulative waiting time is within a predetermined limit (step S203: YES), the process returns to step S201 and obstacle detection and waiting continue. If the obstacle disappears before the cumulative waiting time exceeds the limit (step S201: NO), the process returns to "Continue" as shown in Figure 7, and autonomous driving of the autonomous driving device 100 following the route is resumed under the control of the route driving unit 112.

[0038] If, as a result of continued obstacle detection and waiting, the cumulative waiting time exceeds the limit (step S203: NO), recovery by turning will be performed in the following steps S204 to S207. Figure 12 shows an example of recovery by turning. The recovery process will be explained below with reference to Figures 4, 11, and 12.

[0039] In step S204, the measurement unit 140 performs measurements under the control of the fault confirmation unit 114, and the distance and direction of the obstacle 310 are measured for the right region 410 and the left region 420, which are located to the left and right of the autonomous driving device 100. In other words, the fault confirmation unit 114 corresponds to an example of a confirmation unit, and confirms the obstacle 310 for the left and right regions (i.e., the right region 410 and the left region 420) on either side of the main body 101 of the autonomous driving device 100. Furthermore, step S204 corresponds to an example of the confirmation process as described in the present invention.

[0040] The right-hand region 410 and the left-hand region 420 are areas within a certain detection distance B from the vehicle body center 100a of the autonomous driving device 100. The detection distance B may be the same distance as the setting distance A that defines the aforementioned no-traveling region 320, or it may be a larger distance than the setting distance A to allow for a margin of safety.

[0041] In step S204, the fault confirmation unit 114 has the measurement unit 140 measure the obstacle 310, and also confirms the obstacle 310 in the map information 121 of the storage unit 120. In other words, in this embodiment, the fault confirmation unit 114 confirms the obstacle 310 using the measurement unit 140 and also confirms it using the map information 121. The map information 121 may show obstacles 310 that are difficult to measure by the measurement unit 140, such as steps or ditches. In addition, the map information 121 may contain virtual obstacles 310 that do not actually exist, which may be set in the form of no-entry zones, for example, to limit the area where the autonomous driving device 100 can travel. By confirming the obstacle 310 using the map information 121, the fault confirmation unit 114 can also deal with these cases.

[0042] After the obstacle 310 is identified in step S204, in step S205, the straight line calculation unit 115 calculates approximate straight lines L1 and L2 for the obstacle 310 that is closest to the autonomous driving device 100 in the right region 410 and the left region 420, respectively. In other words, the straight line calculation unit 115 corresponds to an example of a direction calculation unit, and calculates the direction along the obstacle 310 for the left and right regions, respectively. Furthermore, step S205 corresponds to an example of the direction calculation process as described in the present invention.

[0043] Next, in step S206, the angle calculation unit 116 calculates the angle bisector L3, which is formed by the approximate straight line L1 of the right region 410 and the approximate straight line L2 of the left region 420. The angle θ is then calculated, which is formed by a parallel straight line L4 that is parallel to the bisector L3 and passes through the vehicle center 100a, and a center line L0 that passes through the vehicle center 100a and extends in the front-rear direction of the autonomous driving device 100.

[0044] In step S207, the turning reverse unit 117 controls the drive unit 130, simultaneously executing a rotational operation that rotates the autonomous driving device 100 by an angle θ and a reverse operation that moves the autonomous driving device 100 backward, causing the autonomous driving device 100 to turn in the direction of the parallel straight line L4. In other words, the turning reverse unit 117 corresponds to an example of a separation control unit as defined in the present invention, and combines a rotational operation that changes the orientation of the main body 101 toward the intermediate direction of each direction calculated by the straight line calculation unit 115 with a reverse operation that moves the main body 101 backward to move the main body 101 away from the obstacle 310. Furthermore, step S207 corresponds to an example of a separation control process as defined in the present invention.

[0045] By combining reverse movement and rotational movement, the autonomous driving device 100 can quickly move away from obstacles and quickly return to autonomous driving (recovery). The combination of reverse movement and rotational movement includes actions such as rotating in place by an angle θ followed by straight-line reverse movement, or alternating between rotating in place and straight-line reverse movement. However, in this embodiment, the turning reverse unit 117 performs a turning motion that combines reverse movement and rotational movement. The turning motion allows for a quicker move away from obstacles compared to performing rotation in place and straight-line reverse movement separately. Furthermore, in this embodiment, where the main body 101, as viewed from above, has a rectangular shape, a turning motion is desirable because it allows for recovery while avoiding temporary proximity of the corners of the main body 101 to the obstacle 310.

[0046] When the vehicle's center 100a leaves the no-travel zone 320 due to the turning motion in step S207, the obstacle check process ends, and after the "Recovered" stage shown in Figure 7, the process returns to step S101, where the route search unit 111 searches for a travel route and the autonomous driving operation process is executed.

[0047] As shown in Figure 12, in a situation where there is an angle between the obstacle 310 in the right region 410 and the obstacle 310 in the left region 420, such as near a recess in a wall, the recovery described above allows the autonomous driving device 100 to move in an intermediate direction away from both the obstacles 310 in the right region 410 and the left region 420. Figure 13 shows an example of recovery near a linear obstacle 310.

[0048] In the example shown in Figure 13, the obstacle 310 extends linearly across the right region 410 and the left region 420. Therefore, the approximate straight line L1 of the obstacle 310 in the right region 410 coincides with the approximate straight line L2 in the left region 420, and the bisector L3 is a straight line that intersects these approximate straight lines L1 and L2 perpendicularly. Consequently, the parallel straight line L4 passing through the center 100a of the autonomous driving device 100 also intersects the approximate straight lines L1 and L2 perpendicularly, so the autonomous driving device 100 turns in a direction that moves perpendicularly away from the obstacle 310. In other words, in the example shown in Figure 13, the autonomous driving device 100 moves in a direction that moves perpendicularly away from the wall-like obstacle 310. However, in the confirmation of the obstacle 310 in step S204, there are cases where the obstacle 310 is not found in either the right region 410 or the left region 420. Figure 14 shows the recovery process when no obstacle 310 is found in the left region 420.

[0049] In step S204 of Figure 11, if, for example, no obstacle 310 is found in the left region 420, then in step S205, the straight line calculation unit 115 sets the approximate straight line L2 in the left region 420 to be a straight line perpendicular to the center line L0 of the autonomous driving device 100. If no obstacle 310 is found, it is unclear whether the obstacle 310 does not actually exist, or whether an obstacle 310 that actually exists could not be measured. Therefore, in this embodiment, an approximate straight line L2 of the average direction in the case where the obstacle 310 exists is set. In other words, if the obstacle confirmation unit 114 cannot confirm the obstacle 310 in either the left or right region (i.e., the right region 410 and the left region 420), the straight line calculation unit 115 uses the lateral direction as the direction along the obstacle 310 in the region where the obstacle 310 could not be confirmed.

[0050] As a result, the autonomous driving device 100 will turn in a safe direction away from both the measured obstacle 310 and the set approximate straight line L2, enabling a quick recovery.

[0051] In this section, we will discuss the autonomous driving device and the control of the autonomous driving device according to the present invention. While AMRs are cited as an example of the method's application, the application of the autonomous driving device and control method for the autonomous driving device of the present invention is not limited to the above, and it can be used in a wide range of applications, including AGVs (Automatic Guided Vehicles) and autonomous vehicles.

[0052] The embodiments described above should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the embodiments described above, and all modifications within the meaning and scope of the claims are intended to be included. [Explanation of symbols]

[0053] 100: Autonomous driving device, 100a: Center of the vehicle body, 101: Main body, 102: Cargo bed, 103: Wheel, 104: Caster, 105: Front sensor, 106: Rear sensor, 110: Control unit, 111: Path search unit, 112: Path driving unit, 113: Obstacle response unit, 114: Obstacle detection unit, 115: Straight line calculation unit, 116: Angle calculation unit, 117: Turning and reverse unit, 120: Memory unit, 130: Drive unit, 140: Measurement unit, 121: Map information, 122: Unit section, 122_1: Empty unit section, 122_2: Unit section with an object, 122_3: Unknown unit section, 210: Front measurement area, 220: Rear measurement area, 310: Obstacle, 320: No driving area, 410: Right area, 420: Left area,

Claims

1. A confirmation unit that checks for obstacles in each of the left and right areas flanking the main body of the autonomous driving device, A direction calculation unit that calculates the direction along the obstacle for each of the left and right regions, An autonomous driving device comprising: a separation control unit that combines a rotational movement that changes the orientation of the main body toward the intermediate direction of each direction calculated by the direction calculation unit and a reverse movement that moves the main body backward to move the main body away from the obstacle.

2. The autonomous driving device according to claim 1, wherein, if the confirmation unit fails to detect an obstacle in either the left or right region, the direction calculation unit uses the lateral direction as the direction along the obstacle in the region where the obstacle could not be detected.

3. The autonomous driving device according to claim 1 or 2, wherein the confirmation unit confirms the obstacle using a sensor and also using map information.

4. The autonomous driving device according to any one of claims 1 to 3, wherein the separation control unit causes the device to perform a turning operation that combines the reverse operation and the rotation operation.

5. The autonomous driving device according to claim 4, wherein the shape of the main body when viewed from above is rectangular.

6. The process involves checking for obstacles in the left and right areas surrounding the main body of the autonomous driving device, A direction calculation process for calculating the direction along the obstacle for each of the left and right regions, A control method for an autonomous driving device, comprising: a rotational operation that changes the orientation of the main body toward the intermediate direction of each direction calculated in the direction calculation process, and a backward operation that moves the main body backward, which are combined to move the main body away from the obstacle; and a separation control process.

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