Autonomous vehicles and auxiliary control devices

Abstract

This technology provides a way to realize autonomous vehicles that can reliably estimate their own position at a relatively low cost. [Solution] The autonomous vehicle includes a distance sensor 14 that detects the distance to objects in its surroundings, and a vehicle control device 16 that estimates its own position within the environmental map based on the distance data measured by the distance sensor 14 and environmental map information. The autonomous vehicle also includes a tilt detection sensor 118 that detects the tilt of the autonomous vehicle, and an auxiliary control device 120 that relays communication between the distance sensor 14 and the vehicle control device 16, corrects the distance data based on the tilt of the autonomous vehicle detected by the tilt detection sensor 118, and outputs the corrected distance data to the vehicle control device 16.

Description

Technical Field

[0001] The present disclosure relates to an autonomous driving vehicle and an auxiliary device.

Background Art

[0002] Patent Document 1 discloses an autonomous driving vehicle. This autonomous driving vehicle includes a plurality of environmental map informations, selects one environmental map information from the plurality of environmental map informations according to the position and angle of the autonomous driving vehicle, and estimates its own position using the selected environmental map information.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the autonomous driving vehicle of Patent Document 1, when approaching a slope from a horizontal plane or when approaching a horizontal plane from a slope, it is necessary to switch the environmental map used for estimating the own position. In this case, there is a risk of erroneously switching the environmental map due to detection errors in the position and orientation of the autonomous driving vehicle near the boundary between the horizontal plane and the slope, and as a result, there is a risk of losing the own position.

[0005] The present disclosure has been made in view of such a situation, and an exemplary object of one aspect thereof is to provide a technology for realizing an autonomous driving vehicle that can reliably estimate its own position at a relatively low cost.

Means for Solving the Problems

[0006] { / END]] To solve the above problems, an autonomous vehicle according to one aspect of the present disclosure comprises: a distance sensor for detecting the distance to surrounding objects; a vehicle control device for estimating its own position within an environmental map based on distance data measured by the distance sensor and environmental map information; and an auxiliary control device for detecting the tilt of the autonomous vehicle; and relaying communication between the distance sensor and the vehicle control device, correcting the distance data based on the tilt of the autonomous vehicle detected by the tilt detection sensor, and outputting the corrected distance data to the vehicle control device.

[0007] Another aspect of the present disclosure is an auxiliary control device. This device is an auxiliary control device that relays communication between a distance sensor mounted on an autonomous vehicle and a vehicle control device, wherein the distance sensor detects the distance to objects present around the autonomous vehicle, the vehicle control device estimates the position of the autonomous vehicle in the environment map based on the distance data measured by the distance sensor and environment map information, the auxiliary control device corrects the distance data based on the tilt amount of the autonomous vehicle measured by a tilt detection sensor mounted on the autonomous vehicle, and outputs the corrected distance data to the vehicle control device.

[0008] Furthermore, any combination of the above components, or any substitution of the components or expressions of this disclosure between methods, apparatus, systems, etc., is also valid as a form of this disclosure. [Effects of the Invention]

[0009] This disclosure provides a technology that enables the realization of an autonomous vehicle capable of reliably estimating its own position at a relatively low cost. [Brief explanation of the drawing]

[0010] [Figure 1] This is an external view of a conventional autonomous vehicle. [Figure 2] Figure 1 is a schematic diagram of the autonomous vehicle's configuration. [Figure 3] This diagram illustrates the challenges of autonomous vehicles shown in Figure 1. [Figure 4]This is an external view of an autonomous vehicle according to an embodiment. [Figure 5] Figure 4 is a schematic diagram of the autonomous vehicle's configuration. [Figure 6] Figure 5 illustrates an example of point cloud data correction performed by the correction unit. [Figure 7] Figure 4 illustrates the effects of autonomous vehicles. [Figure 8] Figure 8(a) shows the case where the measurement point is the ceiling, and Figure 8(b) shows the case where the measurement point is the floor. [Modes for carrying out the invention]

[0011] Preferred embodiments will be described below with reference to the drawings. These embodiments are illustrative and not limiting to the disclosure, and not all features or combinations thereof described in the embodiments are necessarily essential to the disclosure. The same or equivalent components, members, and processes shown in each drawing will be denoted by the same reference numerals, and redundant descriptions will be omitted where appropriate.

[0012] First, let's describe the conventional autonomous vehicle 1.

[0013] Refer to Figures 1 and 2. The autonomous vehicle 1 is a vehicle that measures the distance to surrounding objects OBJ (e.g., walls, pillars, etc.) to estimate its own position within the environment map and autonomously navigates while avoiding the objects OBJ. The autonomous vehicle 1 is typically a transport device for carrying goods, although this is not always the case; in the illustrated example, it is a forklift.

[0014] The autonomous vehicle 1 comprises a vehicle body 10, a driving unit 12 for moving the autonomous vehicle 1, a distance sensor 14 for measuring the distance to an object OBJ in the vicinity of the autonomous vehicle 1, and a vehicle control device 16 for controlling the movement of the autonomous vehicle 1.

[0015] The running unit 12 has a running function for driving the autonomous driving vehicle 1, and drives the autonomous driving vehicle 1 according to a signal from the vehicle control device 16. The running unit 12 includes, for example, a motor (not shown) and wheels 13, and transmits the rotation of the motor to the wheels 13 to drive the autonomous driving vehicle 1. Note that the running unit 12 is not limited to the motor and the wheels 13 as long as it can drive the autonomous driving vehicle 1.

[0016] The distance sensor 14 is a two-dimensional distance sensor, for example, a two-dimensional Lidar. The distance sensor 14 is attached to the vehicle body 10 of the autonomous driving vehicle 1 so that the measurement plane S1 coincides with the horizontal plane when the autonomous driving vehicle 1 is on a horizontal plane. The distance sensor 14 emits laser light at a predetermined period at a constant angle in the surrounding area on the measurement plane S1, measures the distance to an object OBJ existing in the surrounding area based on the time until the laser light is reflected and returns, and generates point cloud data. The measurement range of the distance sensor 14 may be 360° all around or a predetermined range (for example, 270°). The distance sensor 14 outputs the point cloud data to the vehicle control device 16.

[0017] The vehicle control device 16 is housed inside the vehicle body 10 in the example of FIG. 1, although not limited thereto.

[0018] In FIG. 2, functional blocks are shown for the vehicle control device 16. Each block shown here is realized hardware-wise by elements and mechanical devices such as a processor such as a computer's CPU (Central Processing Unit) and a memory such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and software-wise by a computer program or the like. Therefore, it is understood by those skilled in the art that these blocks can be realized in various forms by combinations of hardware and software. The same applies to the auxiliary control device 120 in FIG. 5 described later.

[0019] The vehicle control device 16 comprises a communication unit 22, a processing unit 24, and a storage unit 26. The processing unit 24 performs various information processing related to the driving of the autonomous vehicle 1. The storage unit 26 stores data that is referenced or updated by the processing unit 24. The communication unit 22 is a communication interface for sending and receiving various types of information with other devices. The processing unit 24 sends and receives data with the distance sensor 14 via the communication unit 22.

[0020] The memory unit 26 stores, for example, environmental map information. The environmental map information may be created by the vehicle control device 16 using known or future available technologies, or it may be created separately externally. In any case, the ring map information is two-dimensional map information parallel to the horizontal plane.

[0021] The processing unit 24 includes a self-position estimation unit 30 and a driving control unit 32.

[0022] The self-position estimation unit 30 uses the point cloud data output by the distance sensor 14 and the environmental map information stored in the storage unit 26 to estimate the self-position, which is the current position of the autonomous vehicle 1 within the environmental map.

[0023] Note that the position of the autonomous vehicle 1 is the position of a single point on the autonomous vehicle 1, which may be, for example, the center of the distance sensor 14, or the center of the vehicle body 10 of the autonomous vehicle 1. In the following, the position of the autonomous vehicle 1 will be assumed to be the position of the distance sensor 14.

[0024] The self-localization unit 30 is implemented using known or future available technologies. For example, the self-localization unit 30 may be implemented using SLAM (Simultaneous Localization and Mapping) technology.

[0025] The driving control unit 32 controls the driving unit 12 to drive the autonomous vehicle 1. Based on the environmental map information and the autonomous vehicle 1's own position estimated by the self-position estimation unit 30, the driving control unit 32 moves the autonomous vehicle 1 to a desired position.

[0026] The above describes the configuration of a conventional autonomous vehicle 1.

[0027] As shown in Figure 3, when the autonomous vehicle 1 travels on slope SL, the distance sensor 14 is tilted relative to the horizontal plane. In this case, a discrepancy occurs between the measurement surface S1 of the distance sensor 14 and the plane S2 represented by the environmental map information, which is parallel to the horizontal plane. Specifically, for example, in the vertical plane (i.e., a certain angle in the circumferential direction) in Figure 3, the distance to the wall as an object OBJ is actually L1, but the distance sensor 14 measures it as L2. Therefore, on slope SL, the accuracy of the autonomous vehicle 1's self-position estimation decreases or it fails to estimate its self-position. Consequently, the autonomous vehicle 1's traversable environments are limited to flat environments without slopes.

[0028] Next, with reference to Figures 4 and 5, we will describe an autonomous vehicle 101 according to an embodiment that solves the above-mentioned problems. We will focus on the differences from Figures 1 and 2.

[0029] The autonomous vehicle 101 comprises a driving unit 12, a distance sensor 14, a vehicle control device 16, a tilt detection sensor 118 for detecting the amount of tilt of the autonomous vehicle 101, and an auxiliary control device 120 for relaying communication between the distance sensor 14 and the vehicle control device 16.

[0030] The autonomous vehicle 101 is an existing autonomous vehicle 1 that is either unused or already in use, to which a tilt detection sensor 118 and an auxiliary control device 120 have been retrofitted.

[0031] The manufacturer that produces and sells the auxiliary control device 120, or the manufacturer that installs the tilt amount detection sensor 118 and the auxiliary control device 120 on the autonomous vehicle 1 to improve the autonomous vehicle 1 into the autonomous vehicle 101, may be the same as or different from the manufacturer that produces and sells the autonomous vehicle 1.

[0032] The tilt detection sensor 118 detects the tilt angle of the distance sensor 14 with respect to the direction of gravity, specifically the tilt angle with respect to the horizontal plane. The tilt detection sensor 118 may include, but is not limited to, an acceleration sensor or an angular velocity sensor, and may also include an inertial measurement unit (IMU).

[0033] The tilt detection sensor 118 is installed so as to tilt together with the distance sensor 14 by the same angle to the horizontal plane as the distance sensor 14 when the body 10 of the autonomous vehicle 101 tilts with respect to the horizontal plane, and therefore the distance sensor 14 attached to the body 10 tilts with respect to the horizontal plane. For example, the tilt detection sensor 118 may be attached to the body 10 like the distance sensor 14, or it may be attached to the distance sensor 14. In any case, the tilt detection sensor 118 is preferably attached near the distance sensor 14. For example, the tilt detection sensor 118 may be attached directly behind the distance sensor 14, for example, with no gap or with a small gap, as shown in the figure.

[0034] The auxiliary control device 120 is mounted on the vehicle body 10. In the example shown in Figure 4, however, the auxiliary control device 120 is located directly behind the distance sensor together with the tilt amount detection sensor 118.

[0035] Figure 5 shows the functional blocks of the auxiliary control device 120. The auxiliary control device 120 comprises a communication unit 122, a processing unit 124, and a storage unit 126.

[0036] The processing unit 124 performs various information processing. The storage unit 126 stores data that is referenced or updated by the processing unit 124. The communication unit 122 is a communication interface for sending and receiving various types of information with other devices. The processing unit 124 sends and receives data with the distance sensor 14 and the vehicle control device 16 via the communication unit 122.

[0037] The processing unit 124 includes a correction unit 134 and a pass-through unit 136.

[0038] The correction unit 134 receives point cloud data output by the distance sensor 14 and corrects it according to the amount of tilt detected by the tilt detection sensor 118. Specifically, the correction unit 134 corrects the point cloud data output by the distance sensor 14 to point cloud data projected onto a horizontal plane. The correction unit 134 transmits the corrected point cloud data to the vehicle control device 16. In particular, the correction unit 134 outputs the corrected point cloud data to the vehicle control device 16 via the communication unit 122 using the same communication protocol as the distance sensor 14.

[0039] As a result, the vehicle control device 16 outputs corrected point cloud data, that is, point cloud data in the same plane as the plane S2 represented by the environmental map information, so that it can estimate its own position in the same way as when traveling on a horizontal plane.

[0040] The pass-through unit 136 passes through the data that the vehicle control device 16 transmits to the distance sensor 14. In other words, the pass-through unit 136 transmits the data that the vehicle control device 16 transmits to the distance sensor 14 to the distance sensor 14 without processing it. An example of such data is the setting parameters of the distance sensor 14, and an example of the setting parameters is the measurement range of the distance sensor 14.

[0041] Next, with reference to Figure 6, an example of point cloud data correction by the correction unit 134 will be explained.

[0042] The component of gravity at the measurement point is expressed by the following equation (1). In equation (1), (,) represents the dot product. The same applies to equations (2) to (4).

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[0043] The component perpendicular to the direction of gravity at the measurement point is expressed by the following equation (2).

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[0044] The correction unit 134 converts the three-dimensional vector represented by equation (2) into the communication protocol of the distance sensor 14 and outputs it to the vehicle control device 16.

[0045] Furthermore, the correction of point cloud data is not limited to this method; it can be achieved using any known or future-available technology.

[0046] Next, the effects of the embodiment will be explained. According to the embodiment, the auxiliary control device 120 relays communication between the distance sensor 14 and the vehicle control device 16, and the auxiliary control device 120 corrects the point cloud data output by the distance sensor 14 according to the amount of tilt and outputs it to the vehicle control device 16. As a result, the autonomous vehicle 101 can estimate its own position when traveling on a slope in the same way as when traveling on a horizontal plane. In addition, according to the embodiment, since the auxiliary control device 120, which is provided separately from the vehicle control device 16, has a function to correct the point cloud data, the autonomous vehicle 101 can be realized by retrofitting the tilt detection sensor 118 and the auxiliary control device 120 to an existing autonomous vehicle 1.

[0047] Furthermore, in this embodiment, there is no need to switch environmental map information, so the problem of losing one's own position due to accidentally switching environmental map information does not occur.

[0048] Furthermore, according to this embodiment, the auxiliary control device 120, rather than the vehicle control device 16, corrects the point cloud data, and the auxiliary control device 120 outputs the corrected point cloud data to the vehicle control device 16 using the same communication protocol as the distance sensor 14. Moreover, the auxiliary control device 120 passes through all the data that the vehicle control device 16 transmits to the distance sensor 14. In other words, according to this embodiment, the point cloud data is corrected by providing the auxiliary control device 120 between the distance sensor 14 and the vehicle control device 16, while the vehicle control device 16 is configured to appear as if it is communicating directly with the distance sensor 14. Therefore, according to this embodiment, there is no need to make any changes to the vehicle control device 16, and thus the autonomous vehicle 1 can be converted to the autonomous vehicle 101 at a relatively low cost. Because there is no need to make any changes to the vehicle control device 16, the autonomous vehicle 1 can be converted to the autonomous vehicle 101 even without understanding the contents of the vehicle control device 16.

[0049] Refer to Figure 7. When the brakes are applied to stop, the vehicle body 10 may tilt. In this case, a momentary discrepancy occurs between the measurement surface S1 of the distance sensor 14 and the plane S2 represented by the environmental map information. In this case, in a conventional autonomous vehicle 1, the accuracy of self-position estimation decreases or self-position estimation fails, resulting in a decrease in stopping accuracy. In contrast, according to this embodiment, the point cloud data is corrected according to the amount of tilt, so the stopping accuracy does not decrease due to tilting caused by braking.

[0050] The present disclosure has been described above based on embodiments. These embodiments are illustrative, and it will be understood by those skilled in the art that various modifications are possible in combinations of their components and processing processes, and that such modifications are also within the scope of the present disclosure. Such modifications will be described below.

[0051] (Variation 1) Refer to Figures 8(a) and 8(b). Although not specifically mentioned in the embodiment, if the autonomous vehicle 101 tilts, for example when the brakes are applied, the distance sensor 14 may measure the distance to the ceiling R or floor F. Since the environmental map information does not include point cloud data of the ceiling R and floor F, point cloud data measuring the distance to the ceiling R or floor F only gets in the way of estimating the vehicle's own position and can negatively affect the estimation of the vehicle's own position.

[0052] Therefore, in this modified example, the correction unit 134 does not transmit to the vehicle control device 16 any point cloud data output by the distance sensor 14 that is determined to have measured the ceiling R or floor F. This prevents point cloud data that measures the distance to the ceiling R or floor F from adversely affecting the estimation of the vehicle's own position.

[0053] More specifically, the correction unit 134 determines that a measurement point x satisfying the following equation (3) is the ceiling R, and that a measurement point x satisfying the following equation (4) is the floor F, and does not transmit data for measurement points x that satisfy either condition to the vehicle control device 16. In other words, the correction unit 134 determines that point cloud data whose height from the mounting height h of the distance sensor 14 is outside a predetermined range is point cloud data measuring either the ceiling R or the floor F, and does not transmit it to the vehicle control device 16.

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[0054] Furthermore, a threshold can be set with a certain range so as not to react too sensitively to variations in mounting height due to changes in the vehicle body 10's posture or to variations due to measurement errors of the distance sensor 14. For example, threshold h roof You may set the threshold h to a value greater than the actual ceiling R height. floorYou may set this to a value smaller than the actual height of the floor surface F.

[0055] Any combination of the embodiments and modifications described above is also useful as an embodiment of this disclosure. The new embodiments resulting from such combinations possess the combined effects of the respective embodiments and modifications. [Explanation of Symbols]

[0056] 1 autonomous vehicle, 14 distance sensor, 16 vehicle control device, 118 tilt detection sensor, 134 correction unit.

Claims

1. A distance sensor that detects the distance to surrounding objects, A vehicle control device that estimates its own position within an environmental map based on distance data measured by the distance sensor and environmental map information, An autonomous vehicle equipped with, A tilt detection sensor for detecting the tilt amount of the autonomous vehicle, An auxiliary control device that relays communication between the distance sensor and the vehicle control device, corrects the distance data based on the tilt amount of the autonomous vehicle detected by the tilt amount detection sensor, and outputs the corrected distance data to the vehicle control device, Equipped with, Autonomous vehicle.

2. The auxiliary control device outputs the corrected distance data to the vehicle control device using the same communication protocol as the distance sensor. The autonomous vehicle according to claim 1.

3. The auxiliary control device passes through the data that the vehicle control device transmits to the distance sensor. The autonomous vehicle according to claim 1.

4. Distance data from the mounting height of the distance sensor that is outside a predetermined range will not be output to the vehicle control device. The autonomous vehicle according to claim 1.

5. An auxiliary control device that relays communication between a distance sensor and a vehicle control device mounted on an autonomous vehicle, The distance sensor detects the distance to objects present around the autonomous vehicle. The vehicle control device estimates the position of the autonomous vehicle within the environmental map based on the distance data measured by the distance sensor and the environmental map information. The auxiliary control device corrects the distance data based on the tilt amount of the autonomous vehicle measured by the tilt amount detection sensor mounted on the autonomous vehicle, and outputs the corrected distance data to the vehicle control device. Auxiliary control device.

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