Turning characteristic setting method for vehicle automatic driving system and vehicle automatic driving system

Abstract

In a turning characteristic setting method for a vehicle automatic driving system, a travel pattern for acquiring parameters of turning characteristics is automatically generated (step S4). Data relating to turning characteristics of the vehicle is acquired while the vehicle is automatically driven in the generated driving mode (step S5). Parameters are set on the basis of the acquired data (step S6).

Description

Technical Field

[0001] The present disclosure relates to a turning characteristic setting method of a vehicle automatic driving system and a vehicle automatic driving system. Background Art

[0002] The vehicle automatic driving system disclosed in the following non-patent document 1 is known. The system disclosed in non-patent document 1 includes a robot for operating a steering wheel, a robot for operating an accelerator pedal and a brake pedal, a robot for operating a gear selector, and a controller for controlling these robots. These robots are installed in a vehicle for use and can also be removed from the vehicle. In addition, the vehicle automatic driving system disclosed in the following patent document 1 is also known. Patent document 1 mainly discloses automatic steering control related to vehicle turning.

[0003] Prior art literature

[0004] Non-patent literature

[0005] Non-patent document 1: "GPS-controlled actual vehicle driving test robot NaviControl," manufactured by Toyo Technology Co., Ltd. (Japan) and HI-TEC srl, [online], [retrieved on February 19, 2022], Internet<URL:https: / / www.toyo.co.jp / mecha / products / detail / navicontrol.html>

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2017-177847 Summary of the invention

[0008] Problems to be solved by the invention

[0009] In the automatic steering control of the automatic driving system, the steering wheels [steered road wheels] are turned by the actuator to turn. In the system disclosed in non-patent document 1, if the robot actuator rotates the steering wheel, the steering wheels are turned via a steering mechanism including a steering column shaft, a steering gear box, etc. When such a system is actually used, adaptation work is required. More specifically, it is necessary to set the parameters of the automatic steering control related to the turning characteristics of the vehicle.

[0010] The object of the present disclosure is to provide a turning characteristic setting method of a vehicle automatic driving system and a vehicle automatic driving system that can efficiently set parameters of an automatic steering control related to the turning characteristics of a vehicle during adaptation of the automatic steering control.

[0011] Means for solving problems

[0012] In the turning characteristic setting method of the vehicle automatic driving system disclosed in the present invention, a driving mode for obtaining parameters of turning characteristics is automatically generated, the vehicle is automatically driven in the generated driving mode while data related to the turning characteristics of the vehicle is obtained, and the parameters are set based on the obtained data.

[0013] Here, the vehicle autonomous driving system may also be constructed by installing an autonomous driving robot on the vehicle.

[0014] Furthermore, before the driving pattern is automatically generated, the driving area may be acquired by driving the vehicle along the periphery of a driving area in which automatic driving of the driving pattern is performed by a driver, and the driving pattern may be automatically generated within the driving area.

[0015] Here, the parameter may be a turning curvature or a turning radius of the vehicle relative to a steering angle of a steering wheel of the vehicle.

[0016] The parameter may be the yaw rate of the vehicle relative to the steering angle of a steering wheel of the vehicle.

[0017] The parameter may be a time constant of a response delay of the yaw rate of the vehicle.

[0018] The parameter may also be a stability factor associated with turning of the vehicle.

[0019] In addition, the vehicle automatic driving system disclosed in the present invention comprises: a steering robot that rotates the steering wheel of the vehicle; a self-position detection device that detects the self-position of the vehicle; and a controller that controls the vehicle automatic driving system, and the controller is configured to automatically generate a driving mode for obtaining parameters of turning characteristics, control the steering robot to make the vehicle automatically drive in the generated driving mode, use the self-position detection device to obtain data related to the turning characteristics of the vehicle, and set the parameters based on the obtained data.

[0020] Here, the steering robot may be mounted on the vehicle in a post-installation manner.

[0021] Effects of the Invention

[0022] According to the turning characteristic setting method of the vehicle automatic driving system or the vehicle automatic driving system of the present disclosure, it is possible to efficiently set the parameters of the automatic steering control related to the turning characteristics of the vehicle during the adaptation operation of the automatic steering control. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a stereoscopic diagram showing the structure of a vehicle automatic driving system according to an embodiment.

[0024] Figure 2 It is a plan view showing the process of the turning characteristic setting method of the above-mentioned system (driving area setting).

[0025] Figure 3 It is a plan view showing the above-mentioned process (movement to the starting position).

[0026] Figure 4 It is a plan view showing the above-mentioned process (automatic driving process: the turning curvature is large).

[0027] Figure 5 It is a plan view showing the above-mentioned process (automatic driving process: small turning curvature).

[0028] Figure 6 It is a graph showing the set parameters of the automatic steering control (the turning curvature with respect to the steering angle).

[0029] Figure 7 is a flow chart of the above setting method.

[0030] Figure 8 This is a graph showing parameters (yaw rate with respect to steering angle) of automatic steering control in another example. DETAILED DESCRIPTION

[0031] Hereinafter, embodiments of an automatic driving system for a vehicle and a method for setting turning characteristics using the system will be described with reference to the accompanying drawings and the like.

[0032] The vehicle automatic driving system of the present embodiment is a system in which a rear-mounted automatic driving robot such as that described in the above-mentioned [Non-Patent Document 1] is mounted on an existing vehicle 1. That is, since the rear-mounted automatic driving robot is mounted on the vehicle 1, an adaptation operation of the automatic steering control is required after the automatic driving robot is mounted. Through this adaptation operation, the parameters of the automatic steering control related to the turning characteristics of the vehicle 1 are set. In addition, the turning characteristics refer to characteristics related to the turning of the vehicle 1, specifically, various state quantities related to the turning of the vehicle 1, such as the turning curvature, turning radius, yaw rate, its time constant, or stability coefficient, or various inherent values ​​that affect the turning performance of the vehicle 1.

[0033] The vehicle 1 of this embodiment includes Figure 1The structure shown. The vehicle 1 is equipped with an automatic driving robot, which is installed in the vehicle in a later installation manner and can perform remote driving or automatic driving. The automatic driving robot includes a steering robot 2 that rotates the steering wheel, a pedal robot 3 that operates an accelerator pedal and a brake pedal, a self-position detection device 4 that detects the self-position of the vehicle 1, and a controller 5 that controls them. The steering robot 2, the pedal robot 3, and the self-position detection device 4 are connected to the controller 5.

[0034] The controller 5 is also connected to a GUI (Graphical User Interface) unit 6 as an input device, and the GUI unit 6 displays various information related to the system and inputs various instructions to the controller 5. In addition, an obstacle detection sensor 7 is also connected to the controller 5. The system of this embodiment also includes a shift robot (not shown) for operating the shift selector, and the shift robot is also connected to the controller 5. These robots are coordinated and controlled by the controller 5.

[0035] The vehicle 1 can be remotely driven or automatically driven by the above-mentioned automatic driving robot without a passenger. However, the vehicle 1 can also be driven by a passenger, i.e., a driver, in the driver's seat in a state where the automatic driving robot is installed, or can be driven by the driver without starting the automatic driving robot. In addition, the driver can drive even when the automatic driving robot is started, and various data can be recorded at this time.

[0036] The steering robot 2 can be implemented in various ways, but in the present embodiment, for example, it is provided with a ring member that is mounted on the rim of the steering wheel and rotates together with the steering wheel. As described above, when the driver drives the vehicle 1, the driver operates the ring member like the rim of the steering wheel. The ring member is fixed to the vehicle body via a bracket or the like, and is rotated by the actuator of the steering robot 2. As described above, the steering robot 2 can be implemented in various ways, and it can also be implemented in a way that it is mounted on the steering wheel and directly operates the rim of the steering wheel.

[0037] The pedal robot 3 can also adopt various forms, but in this embodiment, it includes an actuator for pressing a pedal and is fixed between a seat cushion of a driver's seat and the pedal. The actuators of the steering robot 2 and the pedal robot 3 are controlled by a controller 5 .

[0038] As the self-position detection device 4, for example, a device that uses a satellite positioning system such as GPS (Global Positioning System) and an inertial measurement unit (IMU). The controller 5 is an electronic device composed of a CPU, ROM, RAM, a memory such as SSD or HDD, an I / O device, etc. The GUI unit 6 of this embodiment is a tablet terminal with a touch screen. The obstacle detection sensor 7 is an ultrasonic sensor mounted on the front end of the vehicle 1 in this embodiment, but it can also be a sensor of other forms, and its mounting position is not limited to the front end of the vehicle 1.

[0039] Next, refer to Figure 2 to Figure 5 Floor plan and Figure 7 The parameter setting of the automatic steering control during the adaptation operation of the above-mentioned system is explained with reference to the flowchart and the like.

[0040] First, in this embodiment, the above-mentioned rear-mounted automatic driving robot is mounted on the vehicle 1. That is, the above-mentioned steering robot 2, pedal robot 3, gear robot, controller 5 and GUI unit 6 are installed on the vehicle 1. Then, various specifications such as the wheelbase inherent to the vehicle 1 are input to the system from the GUI unit 6. Here, the default turning radius ( Figure 7 The input information is stored in the storage device of the controller 5.

[0041] In addition, the specifications of the vehicle 1 can also be input as numerical values, and if the system stores a vehicle database, the vehicle model can also be input. In this case, the controller 5 obtains vehicle specifications suitable for the vehicle model from the database based on the input vehicle model. In addition, when the maximum steering angle and minimum turning radius of the steering wheel are known, these numerical values ​​are also input.

[0042] In this embodiment, the default turning radius is calculated using the following equation (1) of the kinematic model of the two-wheeled vehicle. As is well known, the kinematic model of a two-wheeled vehicle is used in simulation to study vehicle dynamics instead of the kinematic model of a four-wheeled vehicle. In this embodiment, the kinematic model of the two-wheeled vehicle is also used to calculate the default turning radius.

[0043] δs=Ktan -1 (L / R) = Ktan -1 (κL) Formula (1)

[0044] Here, δs represents the steering angle, K represents the steering gear ratio, L represents the wheelbase value, R represents the turning radius, and κ represents the turning curvature. The turning radius R and the turning curvature κ are inversely related. In addition, when the steering angle of the steering wheel, i.e., the front wheel, can be obtained and the steering gear ratio K is clear, the default turning radius can be determined by using the steering angle δ of the steering wheel (Kδ=δs) instead of the steering angle δs of the steering wheel. In this way, the initial setting for the adaptation operation is performed.

[0045] Then, the vehicle 1 is driven automatically to automatically obtain data related to the turning characteristics of the vehicle 1, and the parameters of the automatic steering control are set based on the obtained data. However, when driving automatically, it is necessary to make the system remember the driving area X used for automatic driving. Therefore, through the actual driving of the driver, such as Figure 2 As shown, the vehicle 1 is driven along the outer periphery Y of the driving area X ( Figure 7 Step S2). At this time, the driving track of the vehicle 1 is detected by the own position detection device 4 and becomes a closed track. The inside of the closed track is determined as the driving area X where the vehicle 1 automatically drives for the adaptation operation based on the automatic driving.

[0046] At this time, the vehicle 1 is traveling at a slow speed (about 5 km / h), for example. Figure 2 In the example, the driving area X is a simple rectangle, but even if the driving area X is a more complex shape, the driving area X can be set accurately and simply by driving the vehicle 1 along its periphery. In addition, the self-position detection of the vehicle 1 for setting the driving area X and the self-position detection of the vehicle 1 during the subsequent automatic driving are both performed by the same self-position detection device 4. Therefore, the automatic driving immediately after the driving area X is set can be reliably performed. In addition, when the driver actually drives along the periphery Y, data related to the acceleration and deceleration characteristics of the vehicle 1 with respect to the pedal operation are also obtained at the same time and stored in the controller 5.

[0047] After the setting of the driving area X is completed, the vehicle 1 Figure 3 Specifically, a map of the travel area X is shown on the GUI unit 6 as in a navigation system, in which the vehicle 1 and the start position S are shown, and the driver transports the vehicle 1 to the start position S with reference to the GUI unit 6 ( Figure 7 The position where the circular trajectory with the maximum radius can be arranged in the driving area X is determined as the starting position S by calculation of the controller 5. However, the starting position S may be arbitrarily set by the driver (user) using the GUI unit 6.

[0048] Next, a plurality of driving patterns ( Figure 7Step S4). For example, in this embodiment, the turning curvature relative to the steering angle of the steering wheel is obtained as the turning characteristic, but as shown in the following [Table 1], the driving pattern is generated every 10 degrees of the steering angle. In addition, regarding the steering angle in Table 1, a positive value indicates a right turn, and a negative value indicates a left turn. In addition, the above-mentioned default turning radius is also shown in [Table 1].

[0049] [Table 1]

[0050]

[0051] The driving route is automatically generated in such a way that the driving route is contained in the predetermined driving area X. For example, Figure 4 As shown in the driving route R1 in FIG. 1 , if the steering angle is large and the turning radius is small, the vehicle can make a circle within the driving area X and return to the starting position S. However, if Figure 5 As shown in the driving route R2 in FIG, if the steering angle is small and the turning radius is large, it is impossible to make a full turn in the driving area X. In such a case, after the driving route R2 that turns at a predetermined steering angle for data acquisition is performed, driving routes Z1 to Z3 for returning to the starting position S are generated using a Dubins path or the like, which is a route generation method based on straight lines and arcs. Here, the return route to the starting position S is composed of the semicircular driving route Z1, the straight driving route Z2, and the semicircular driving route Z3. When transferring from the right-turn driving route to the left-turn driving route, the return route is generated in such a way that the driving direction from the starting position S becomes reversed. In this way, all driving routes are automatically generated.

[0052] Once the entire driving route is determined, the vehicle automatically drives based on the driving route in sequence through unmanned driving, i.e., automatic driving, to obtain data related to the turning characteristics ( Figure 7 Steps S5 and S6). Automatic driving starts from a driving route with a large steering angle, i.e., a small turning radius. Thus, the unmeasured data in the above [Table 1] are measured in sequence and the table is filled.

[0053] After all data is acquired, calculations are performed based on the acquired data. Figure 6 The parameters of the automatic turning control as shown in Figure 7 In this embodiment, the operation parameter is a parameter representing Figure 6 The characteristic curve on the graph of the relationship between the steering angle and the curvature of the steering shown in FIG. In addition, as mentioned above, the data obtained is the data for every 10 degrees of the steering angle. Therefore, when generating Figure 6When mapping, the least square method or the like is used to generate a characteristic curve. In addition, the coefficients and the inherent values ​​in the above formula (1) can be corrected based on the generated parameters, and the default values ​​for the unobtained data can be reset. In addition, in the present embodiment, data for both right turns and left turns are obtained, but data for one can also be generated based on the data for the other.

[0054] In addition, in steps S5 and S6, the deviation of the acquired data from the default value may be monitored, and the data acquisition may be interrupted when the deviation is large. In addition, in steps S5 and S6, the controller 5 always grasps the own position of the vehicle 1 via the own position detection device 4 for the above-mentioned data acquisition. Therefore, in the case of deviation from the driving area X, or in the case of an obstacle detected by the obstacle detection sensor 7, the controller 5 may also output an error. In the case of outputting an error in this way, the user is prompted to move the vehicle 1 to the starting position S. As described above, the adaptation operation of the automatic turning control is completed, and then the automatic driving is appropriately performed.

[0055] In addition, in the above embodiment, as the parameters of the automatic turning control, Figure 6 The characteristic curve of the turning curvature versus the steering angle is shown. However, other parameters can also be set. For example, Figure 8 As shown, the characteristic curve of the yaw rate with respect to the steering angle may also be set as a parameter of the automatic turning control. In this case, the yaw rate is also acquired as data during the automatic driving of the above-mentioned steps S5 and S6. In this embodiment, the yaw rate can be detected by the self-position detection device 4 having GPS and IMU.

[0056] Alternatively, the time constant of the response delay of the yaw rate may be set as a parameter of the automatic turning control. In particular, in a system using a rear-mounted automatic driving robot such as in the present embodiment, response delay is prone to occur. Therefore, by setting the time constant of the response delay as a parameter and using the parameter for the subsequent automatic turning control, automatic driving can be appropriately performed. In this case, the yaw rate is also obtained as data during the automatic driving of steps S5 and S6, and the time constant is calculated based on the data.

[0057] Alternatively, the stability coefficient of the vehicle 1 may be set as a parameter of the automatic turning control. The stability coefficient A can be obtained by the following formula (2).

[0058] R=(1+AV 2 )KL / δs Formula (2)

[0059] Here, A is the stability coefficient, V represents the driving speed, δs represents the steering angle, K represents the steering gear ratio, L represents the wheelbase value, and R represents the turning radius.

[0060] The stability coefficient A is an index indicating the steering characteristics of the vehicle 1, and it is possible to know whether the vehicle 1 is in an oversteering tendency or an understeering tendency through this value. In this case, in the automatic driving of the above-mentioned steps S5 and S6, the accelerator pedal is also controlled to change the driving speed to drive and obtain the turning radius. In addition, the parameter set for the automatic turning control is not limited to one, and two or more parameters may be set at the same time.

[0061] According to the turning characteristic setting method of the vehicle automatic driving system of the present embodiment, (a) a driving pattern for obtaining parameters of turning characteristics is automatically generated. Then, (b) data related to the turning characteristics of the vehicle 1 is obtained while the vehicle 1 is automatically driven in the generated driving pattern. (c) Parameters related to the turning characteristics are set based on the obtained data. Therefore, the parameters of the automatic steering control related to the turning characteristics of the vehicle 1 can be efficiently set in the adaptation operation of the automatic steering control.

[0062] For example, when a company or the like has a large number of vehicles and wants to make these vehicles automatically travel, the adaptation operation of each vehicle can be efficiently performed. At this time, even if the models of these vehicles are not unified but different, the adaptation operation can be efficiently performed for each vehicle.

[0063] In particular, as in the above-mentioned embodiment, when constructing an autonomous driving system by mounting an autonomous driving robot such as a steering robot 2 on a vehicle 1, adaptation work is necessary for each vehicle 1. Therefore, by using the above-mentioned steps (a) to (c), the parameters of the turning characteristics can be set for each vehicle 1 very efficiently.

[0064] In addition, according to the turning characteristic setting method of the vehicle automatic driving system of the above-mentioned embodiment, before automatically generating the driving mode, the driving area X is acquired by driving the vehicle 1 along the outer periphery Y of the driving area X where the driving mode is automatically driven by the driver. Thereafter, the driving mode is automatically generated in the driving area X. As the driving area X used in the adaptation operation, there is no problem as long as a very wide flat land can be prepared, but in most cases, it is difficult to prepare such a driving area X. In addition, the shape of the driving area X also varies, but since the driving area X can be determined simply and reliably, the subsequent driving route can also be reliably automatically generated.

[0065] If the parameter is the turning curvature or turning radius of the vehicle 1 relative to the steering angle of the steering wheel of the vehicle 1, the turning curvature or turning radius, which is the output of the automatic steering control, can be reliably controlled relative to the steering angle, which is the input of the automatic steering control.

[0066] If the parameter is the yaw rate of the vehicle 1 relative to the steering angle of the steering wheel of the vehicle 1 , the yaw rate which is the output of the automatic steering control can be reliably controlled relative to the steering angle which is the input of the automatic steering control.

[0067] If the parameter is the time constant of the response delay of the yaw rate of the vehicle 1, reliable automatic steering control can be performed in consideration of the response delay. As described above, response delay is prone to occur in a system using a rear-mounted automatic driving robot, so by setting the time constant of the response delay as a parameter and using the parameter in the subsequent automatic turning control, automatic driving can be appropriately performed.

[0068] If the parameter is a stability factor related to the turning of the vehicle, it is possible to perform reliable automatic steering control in consideration of the turning characteristics of the vehicle 1 .

[0069] The vehicle automatic driving system of the above-mentioned embodiment includes a steering robot 2 for rotating the steering wheel of the vehicle 1, a self-position detection device 4 for detecting the self-position of the vehicle 1, and a controller 5 for controlling the system. The controller 5 automatically generates a driving mode for obtaining parameters of turning characteristics. The controller 5 controls the steering robot 2 to make the vehicle 1 automatically drive in the generated driving mode, while using the self-position detection device 4 to obtain data related to the turning characteristics of the vehicle 1. The controller 5 sets the parameters based on the obtained data. Therefore, according to the vehicle automatic driving system of the above-mentioned embodiment, the parameters of the automatic steering control related to the turning characteristics of the vehicle 1 can be efficiently set in the adaptation operation of the automatic steering control.

[0070] In particular, when the steering robot is mounted on a vehicle in a post-installed manner as in the above embodiment, adaptation work is required for each vehicle 1. Therefore, according to the vehicle automatic driving system of the above embodiment, parameters of turning characteristics can be set for each vehicle 1 very efficiently.

[0071] Furthermore, in the above-mentioned embodiment, a vehicle automatic driving system is realized by installing a rear-mounted automatic driving robot on the vehicle. However, the vehicle automatic driving system disclosed in the present invention also includes a system in which an automatic driving system is integrated into the vehicle itself. Even such a system integrated into the vehicle requires adaptation work, that is, parameter setting of automatic driving control related to turning characteristics. In this case, since an automatic driving robot is not installed, when setting the parameters of the automatic steering control, the operating angle of the steering wheel and the operating stroke of the accelerator pedal and the brake pedal are detected by various detection sensors installed on the vehicle.

[0072] In the above embodiment, the yaw rate is obtained by the self-position detection device 4 having GPS and IMU, but the yaw rate may be detected by a yaw rate sensor mounted on the vehicle 1. In addition, in the above embodiment, the self-position detection device 4 is a device having GPS and IMU, but it may be a device using SLAM (Simultaneous Localization And Mapping). In the case of the self-position detection device 4 using SLAM, the self-position detection device 4 has a three-dimensional scanner or camera that scans the surrounding environment.

[0073] In addition, according to the present disclosure, by appropriately adapting the automatic turning control of the vehicle, the safety of autonomous driving can be improved. Therefore, for example, it is possible to contribute to Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, which is to "strengthen infrastructure, promote inclusive and sustainable industrialization, and promote the development of technological innovation."

[0074] The entire contents of Japanese Patent Application No. 2022-69844 (filed on April 21, 2022) are incorporated herein by reference.

[0075] Explanation of symbols

[0076] 1 vehicle,

[0077] 2 Turn to robot,

[0078] 4. Self-position detection device,

[0079] 5. Controller,

[0080] X driving area,

[0081] Y (the outer periphery of the driving area X).

Claims

1. A method for setting turning characteristics of a vehicle automatic driving system, characterized in that: Automatically generate a driving pattern for obtaining parameters of turning characteristics, causing the vehicle to automatically drive in the generated driving pattern and acquiring data related to the turning characteristics of the vehicle, The parameters are set based on the acquired data.

2. The turning characteristic setting method according to claim 1, characterized in that: The vehicle autonomous driving system is constructed by installing an autonomous driving robot on the vehicle.

3. The turning characteristic setting method according to claim 1 or 2, characterized in that: Before the driving mode is automatically generated, the driving area is acquired by driving the vehicle along the periphery of the driving area in which the driving mode is automatically driven by the driver. The driving mode is automatically generated within the driving area.

4. The turning characteristic setting method according to claim 3, characterized in that: The parameter is a turning curvature or a turning radius of the vehicle relative to a steering angle of a steering wheel of the vehicle.

5. The turning characteristic setting method according to claim 3, characterized in that: The parameter is the yaw rate of the vehicle relative to a steering angle of a steering wheel of the vehicle.

6. The turning characteristic setting method according to claim 3, characterized in that: The parameter is a time constant of a response delay of the yaw rate of the vehicle.

7. The turning characteristic setting method according to claim 3, characterized in that: The parameter is a stability factor associated with turning of the vehicle.

8. A vehicle automatic driving system, characterized in that: The vehicle automatic driving system comprises: a steering robot, which turns the vehicle’s steering wheel; an own position detection device for detecting the own position of the vehicle; and a controller that controls the vehicle autonomous driving system, The controller automatically generates a driving mode for obtaining parameters of turning characteristics, controls the steering robot to make the vehicle automatically drive in the generated driving mode, uses the self-position detection device to obtain data related to the turning characteristics of the vehicle, and sets the parameters based on the obtained data.

9. The vehicle automatic driving system according to claim 8, characterized in that: The steering robot is mounted on the vehicle in a post-installation manner.

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