WO2022070513A1

WO2022070513A1 - Traveling control system, steering device, and autonomous driving vehicle

Info

Publication number: WO2022070513A1
Application number: PCT/JP2021/021532
Authority: WO
Inventors: 知也藪崎; 浩之森田; 真一片山
Original assignee: ヤマハ発動機株式会社
Priority date: 2020-09-30
Filing date: 2021-06-07
Publication date: 2022-04-07
Also published as: JPWO2022070513A1

Abstract

Provided are a traveling control system, a steering device, and an autonomous driving vehicle capable of making a trajectory of a rear wheel proper when a vehicle turns along a travel path. This control system (1) includes: a first guide sensor (31) that outputs a signal corresponding to the location (Q1) of a guide; a guide location detection unit that, when a detection region (A1) defined in a vehicle body in a vehicle body left-right direction passes through the guide while a vehicle (10) is traveling, detects the location of the guide in the detection region (A1) on the basis of the output of the first sensor; and a target steering angle calculation unit that calculates a target steering angle of the vehicle on the basis of a virtual point defined behind the region and the location of the guide in the region detected by the guide location detection unit.

Description

Driving control systems, steering devices, and self-driving vehicles

The present invention relates to a travel control system, a steering device, and an autonomous driving vehicle.

The following Patent Documents 1 to 4 disclose an autonomous driving vehicle that can travel along a traveling route. In Patent Documents 1, 3 and 4, magnetic marks are filled along a traveling path at regular intervals. The vehicle can travel along the traveling route by detecting the magnetic marks in order with the magnetic sensor. In Patent Document 2, instead of the magnetic mark, transponders that transmit position information are embedded in the traveling path at regular intervals. The vehicle can travel autonomously by receiving the position information transmitted by the transponder by the information receiver.

Jitsufuku 04-045041 Gazette Patent No. 5390360 Patent No. 5423704 Japanese Unexamined Patent Publication No. 06-012119

When an autonomous vehicle turns along a curve in the middle of a travel route, the rear wheels are more than the front wheels due to the difference in the inner wheels of the vehicle, even if the vehicle travels along the center line of the predetermined travel route. Also goes through the inner trajectory. Therefore, when a magnetic mark or the like is provided on the traveling path, it is necessary to take the inner ring difference into consideration. Since the inner ring difference depends on the wheelbase of the vehicle, it requires complicated work to install a magnetic mark or the like in consideration of the inner ring difference. This tends to be a big problem when constructing a travel route on which a plurality of types of autonomous vehicles of different sizes travel.

(1) The travel control system proposed in the present disclosure is a travel control system mounted on a vehicle traveling along a guide defined on a travel path, and outputs a signal according to the position of the guide. A guide position that detects the position of the guide in the region based on the output of the first sensor when the one sensor and the region defined by the vehicle body along the left-right direction of the vehicle body pass through the guide when the vehicle is traveling. Target steering angle for calculating the target steering angle of the vehicle based on the detection unit, the virtual point defined behind the region, and the position of the guide in the region detected by the guide position detection unit. It has a calculation unit. According to this system, the trajectory of the rear wheels can be optimized when the vehicle turns along the traveling path.

(2) In the travel control system of (1), the target steering angle calculation unit passes the position of the guide in the region where the locus of the virtual point due to the travel of the vehicle passes through the region detected by the guide position detection unit. You may calculate the target steering angle so as to do so. According to this, it is possible to improve the followability of the vehicle to the traveling route.

(3) In the travel control system of (1), the first sensor may be arranged in the area. The first sensor may be a sensor that outputs a signal corresponding to the position of the guide in the first sensor when the first sensor passes through the guide while the vehicle is traveling. According to this, the position of the traveling path can be detected by using the first sensor.

(4) In the travel control system of (1), the guide position detection unit detects the position of the guide detected at the first time point as the position of the first guide, and the target steering angle calculation unit is the first. At the second time point after the first time point, the target steering angle may be calculated based on the relative position between the position of the first guide and the virtual point at the second time point. According to this, the virtual point can be effectively followed by the guide.

(5) In the travel control system of (4), the second time point is a time point when the vehicle has advanced a predetermined distance from the position at the first time point, and the second guide detected before the first guide. It may be the time when the virtual point P arrives at, or the time when a predetermined time has elapsed from the first time.

(6) In the travel control system of (1), the target steering angle calculation unit is based on the distance from the region to the virtual point and the position of the guide in the region detected by the guide position detection unit. The target steering angle may be calculated.

(7) The travel control system of (1) may include a virtual point position changing unit that changes the position of the virtual point according to the driving situation of the vehicle. According to this, the behavior of the vehicle can be appropriately controlled according to the driving condition of the vehicle.

In the travel control system of (8) and (7), the virtual point position changing unit may change the position of the virtual point in the left-right direction of the vehicle body according to the driving situation of the vehicle. According to this, it is possible to appropriately control the behavior of the vehicle when the vehicle turns or turns left or right.

In the travel control system of (9) and (7), the virtual point position changing unit may change the position of the virtual point in the front-rear direction of the vehicle body according to the driving situation of the vehicle. According to this, it is possible to appropriately control the followability of the vehicle to the traveling route and the riding comfort of the vehicle according to the driving condition of the vehicle.

(10) In the travel control system of (1), a value that specifies a target turning locus according to the position of the guide in the left-right direction of the vehicle body detected based on the output of the first sensor and the position of the virtual point. May be calculated and the target steering angle may be calculated based on the value corresponding to the target turning locus. According to this, the target steering angle can be calculated in consideration of the target turning locus of the vehicle.

(11) The travel control system of (1) may further have a second sensor installed behind the region and outputting a signal according to the position of the guide. Further, the travel control system of (1) may correct the target steering angle based on the output of the second sensor. According to this, it is possible to more effectively improve the followability of the vehicle to the traveling route.

(12) The steering device proposed in the present disclosure includes the traveling control system of (1), steering, and an actuator for rotating the steering. According to this steering device, when the vehicle turns along the traveling path, the trajectory of the rear wheels can be optimized.

(13) The self-driving vehicle proposed in the present disclosure has the driving control system of (1). According to this, when the vehicle turns along the traveling path, the trajectory of the rear wheels can be optimized.

In the self-driving vehicle of (14) and (13), the virtual point is arranged between the tires of the left and right rear wheels in a plan view. According to this, when the vehicle turns along the traveling path, the trajectory of the rear wheels can be optimized.

It is a block diagram which shows the hardware composition of a vehicle. It is a schematic diagram which shows the outline of the traveling control. It is a schematic diagram which shows the outline of the target steering angle calculation method. It is a figure which shows the relationship between the target turning radius and the target steering angle. It is a functional block diagram which shows an example of the functional structure of a travel control system. It is a flow chart which shows an example of the automatic traveling process. It is a flow chart which shows an example of a steering angle control process. It is a schematic diagram which shows the posture of the vehicle when the vehicle travels along the guide. It is a schematic diagram which shows the posture of the vehicle when the vehicle travels along the guide. It is a schematic diagram which shows the outline of the traveling control. It is a schematic diagram which shows the outline of the running control when the position of a virtual point is changed in the left-right direction of a vehicle body. It is a schematic diagram which shows the outline of the running control when the position of a virtual point is changed in the left-right direction of a vehicle body. It is a schematic diagram which shows the outline of the running control when the position of a virtual point is changed in the left-right direction of a vehicle body. It is a schematic diagram which shows the outline of the running control when the position of a virtual point is changed in the left-right direction of a vehicle body. It is a schematic diagram which shows the outline of the calculation method of the target steering angle when the position of a virtual point is changed in the left-right direction of a vehicle body. It is a schematic diagram which shows the outline of the running control when the position of a virtual point is changed in the front-rear direction of a vehicle. It is a schematic diagram which shows the outline of the calculation method of the target steering angle θ when the position of a virtual point is changed in the front-rear direction of a vehicle. It is a functional block diagram which shows an example of the functional structure of a travel control system. It is a flow chart which shows an example of the automatic driving process. It is a flow chart which shows an example of a steering angle control process. It is a figure for demonstrating the correction of the target steering angle performed in the vehicle which has the 2nd guide sensor. It is a schematic diagram which shows the outline of the traveling control. It is a schematic diagram which shows the outline of the traveling control. It is a functional block diagram which shows an example of the functional structure of a travel control system. It is a flow chart which shows an example of the automatic driving process. It is a flow chart which shows an example of a steering angle control process.

[1. First Embodiment]
The travel control system 1 described in the present disclosure is mounted on the autonomous driving vehicle 10 (see FIG. 1). Hereinafter, the traveling control system 1 is referred to as a control system 1, and the autonomous driving vehicle 10 is referred to as a vehicle 10. First, an example of the embodiment of the present disclosure (first embodiment) will be described.

[1-1. Overview of self-driving vehicles]
The vehicle 10 travels along a guide defined on the travel path. The driving path is laid in a limited area where the running of general vehicles is restricted, such as an amusement park, a golf course, an event venue, and a sightseeing spot. Not limited to this, the travel path may be a public road in which the travel route of the vehicle 10 is set in advance. The guide is installed in the traveling path in order to guide the traveling of the vehicle 10 along the traveling path. In the present embodiment, an example in which the guide is a guide line continuously embedded in the traveling path along the traveling path will be described.

FIG. 1 is a block diagram showing the hardware configuration of the vehicle 10. As shown in FIG. 1, the vehicle 10 has an ECU (Engine Control Unit) 11 and an MCU (Motor Control Unit) 12. The ECU 11 has an arithmetic unit 11a and a storage device 11b. The motor drive device 12 has an arithmetic unit 12a, a storage device 12b, and a drive circuit 12c. The

arithmetic units

11a and 12a may include, for example, a CPU (Central Processing Unit) and an FPGA (Field Programmable Gate Array). The

storage devices

11b and 12b may include, for example, a RAM (RandomAccessMemory) and a ROM (ReadOnlyMemory). The drive circuit 12c receives electric power from a battery (not shown) and supplies electric power according to a command value input from the ECU 11 to a steering actuator described later, a vehicle drive motor 22 which is a drive source of the vehicle 10, and the like. The ECU 11 may be composed of a plurality of devices connected to each other via a network mounted on the vehicle 10 (for example, CAN (Controller Area Network)). In this case, each device constituting the ECU 11 may include at least one of an arithmetic unit and a storage device.

Further, as shown in FIG. 1, the vehicle 10 has a steering device 21, a vehicle drive motor 22, and a brake device 23. The steering device 21 is a device for steering the front wheels 15, and includes, for example, a steering 17, a steering shaft connected to the steering 17, and an actuator (steering actuator) for rotating the steering 17 and the steering shaft 17a. The steering device 21 also includes a tie rod that connects the steering shaft 17a and the front wheels 15. Further, the vehicle 10 has an angle sensor that detects the rotation angle (steering angle) of the steering shaft 17a.

The vehicle drive motor 22 is a device that rotates the drive wheels (one or both of the front wheels 15 and the rear wheels 16) and functions as a drive source. The motor drive device 12 described above may include, as the drive circuit 12c, an inverter that generates an alternating current to be supplied to the vehicle drive motor 22. The drive source of the vehicle 10 may be an engine. Further, the drive source may include both an engine and a vehicle drive motor. A transmission or a speed reducer may be arranged on the power transmission path between the vehicle drive motor 22 and the drive wheels. The brake device 23 is a device that applies a braking force to the wheels, and includes, for example, a foot pedal and a control valve that is connected to the foot pedal via hydraulic pressure. The drive circuit 12c of the motor drive device 12 may supply electric power to the pump or solenoid that drives the control valve.

The vehicle 10 shown in FIG. 1 is a four-wheeled vehicle, but the vehicle 10 is not limited to this, and the vehicle 10 is a three-wheeled vehicle (a vehicle having one front wheel and two rear wheels, or two front wheels and one rear wheel. It may be a vehicle having a) or a two-wheeled vehicle. The vehicle 10 may have five or more wheels such as a bus. Further, although it is possible for a plurality of users to get on the vehicle 10 in FIG. 1, the vehicle 10 may be for one person.

Further, as shown in FIG. 1, the vehicle 10 has a guide sensor 31 that detects the position of a guide on a traveling road, and an outside world sensor 32 that detects the position of a feature around the vehicle 10. In the first embodiment, the guide line 7 (see FIG. 2) is used as a guide as described later. The guide sensor 31 is a sensor that magnetically detects the position of the guide wire 7, and is composed of, for example, a plurality of coils arranged in the left-right direction of the vehicle body. The guide sensor 31 may include an RFID reader for reading the data recorded on the RF tag installed on the track. Information about the track is recorded on the RF tag. For example, the RF tag indicates a stop position, a right turn point, or a left turn point. For example, the RF tag contains information that prompts the vehicle to accelerate / decelerate, stop, turn left / right, change course, etc., information that indicates that the vehicle is at a predetermined point (destination or intersection), and indicates that there is an obstacle in front of the RF tag. It contains information, information indicating that the road is closed, information indicating that the road is straight or curved, and information indicating that wild animals may pop out on the road.

The outside world sensor 32 is a sensor for detecting obstacles, buildings, road signs, and lanes around the vehicle 10, such as a camera and a sensor such as LiDAR (Light Detection and Ranging). The vehicle 10 may have a plurality of types of sensors (for example, both a camera and LiDAR) as the outside world sensor 32.

[1-2. Overview of driving control]
FIG. 2 is a schematic diagram showing an outline of traveling control executed by the control system 1. As shown in FIG. 2, a guide line (for example, an electric wire through which an alternating current is passed) 7 is embedded in the travel path as a guide for guiding the travel path. The control system 1 executes the travel control of the vehicle 10 so that the vehicle 10 travels along the guide line 7. For example, as shown in FIG. 2, when the guide line 7 draws a right curve with respect to the traveling direction of the vehicle 10, the control system 1 tilts the front wheel 15 to the right so that the vehicle 10 turns to the right. Perform steering control. The control system 1 calculates the target steering angle θ of the front wheels 15 by the method described in detail below, and executes steering control for tilting the front wheels 15 toward the target steering angle θ.

[1-3. Calculation of target steering angle]
As shown in FIG. 2, in the vehicle 10, a detection region A1 for detecting the position of the guide line 7 in the left-right direction of the vehicle body is defined along the left-right direction (vehicle width direction) of the vehicle body. The length of the detection area A1 in the left-right direction may correspond to the entire width of the vehicle body. For example, the length of the detection region A1 in the left-right direction may be larger than 70% of the total width of the vehicle body. In the example of the vehicle 10, the guide sensor 31 described above is installed in the detection area A1. The detection region A1 is defined over the right side and the left side with the center in the left-right direction of the vehicle body interposed therebetween. In the plan view shown in FIG. 2, the detection region A1 may be provided, for example, in front of the center of the vehicle 10 in the front-rear direction.

Further, as shown in FIG. 2, a virtual point P is defined behind the detection area A1. In the plan view shown in FIG. 2, the virtual point P is defined as the center position in the left-right direction of the vehicle body. Further, the virtual point P may be defined behind the center of the vehicle 10 in the front-rear direction. More specifically, the virtual point P may be defined between the tires attached to the left and right rear wheels 16 in the plan view of the vehicle body. That is, the virtual point P may be defined behind the front end of the tire and in front of the rear end of the tire. In the example shown in FIG. 2, the virtual point P overlaps with the axle of the rear wheel 16. The distance between the detection area A1 and the virtual point P is, for example, larger than 30% with respect to the wheelbase (distance between the front wheels and the rear wheels). The distance between the detection area A1 and the virtual point P may be larger than, for example, 50%. Further, the distance between the detection area A1 and the virtual point P may be larger than 70% with respect to the wheelbase. The virtual point P may be arranged behind the axle of the rear wheel 16 or may be arranged behind the vehicle 10.

When the detection area A1 passes through the guide (guide line 7 in this embodiment) while the vehicle 10 is traveling, the control system 1 detects the position Q1 of the guide line 7 in the detection area A1. Then, the control system 1 calculates the target steering angle θ of the vehicle 10 based on the virtual point P defined behind the detection region A1 and the position Q1 of the detected guide line 7. The control system 1 calculates the target steering angle θ so that the virtual point P faces the position Q1 of the guide line 7 detected in the detection area A1.

The detection of the position Q1 of the guide line 7 in the detection area A1 is performed by using the guide sensor 31. The guide sensor 31 outputs a signal corresponding to the position Q1 of the guide. In the present embodiment, the guide sensor 31 outputs a signal corresponding to the strength and position of the magnetic field formed by the current flowing through the guide wire 7.

As described above, the guide sensor 31 may be arranged in the detection area A1. As a result, the detection area A1 becomes the detection area of the guide sensor 31, and when the guide sensor 31 arranged in the detection area A1 while the vehicle 10 is traveling passes through the guide (in the present embodiment, the guide line 7), the detection area A signal corresponding to the position of the guide wire 7 in A1 is output by the guide sensor 31.

FIG. 3 is a schematic diagram showing an outline of a method for calculating the target steering angle θ. For example, the control system 1 calculates a value for specifying a target turning locus, which is a locus that the virtual point P should pass, based on the detected position Q1 of the guide line 7 and the position of the virtual point P, and uses this value as the value. The target steering angle θ is calculated based on this. For example, as shown in FIG. 3, the control system 1 measures the deviation width D1 from the center position of the vehicle 10 in the left-right direction to the position Q1 of the guide line 7. Then, based on this deviation width D1 and the distance L1 from the detection region A1 in the front-rear direction of the vehicle 10 to the virtual point P, the target turning locus, which is the locus that the virtual point P should pass by turning the vehicle 10, is obtained. A specified value is calculated, and the target steering angle θ is calculated based on this value. The "value that specifies the target turning locus" indicates the radius, diameter, curvature, and the like of the turning in the target turning locus. The control system 1 calculates, for example, the target turning radius R, which is the turning radius in the target turning locus, and calculates the target steering angle θ based on the target turning radius R.

FIG. 4 is a diagram showing an example of the relationship between the target turning radius R and the target steering angle θ. As shown in FIG. 4, the target steering angle θ decreases as the target turning radius R increases. The target steering angle θ can be calculated by obtaining the target turning radius R.

The target steering angle θ may be calculated by a predetermined formula with the target turning radius R as a variable, or data stored in advance in a storage device 11b or the like of the ECU 11 (for example, the target steering angle θ and the target turning). It may be calculated based on (two-dimensional array data) in which the radius R is associated with one-to-one.

The target turning radius R becomes smaller as the deviation width D1 of the guide in the left-right direction of the vehicle body becomes larger, for example. Further, the target turning radius R increases as the distance L1 from the detection region A1 to the virtual point P in the front-rear direction of the vehicle 10 increases. Since the distance L1 from the detection area A1 to the virtual point P is known, the target turning radius R can be calculated by measuring the deviation width D1 of the guide in the left-right direction. The target steering angle θ can be calculated based on this target turning radius R.

The target turning radius R may be calculated by a predetermined calculation formula having the deviation width D1 and the distance L1 as variables, or data stored in advance in the storage device 11b or the like of the ECU 11 (for example, the target turning radius R). , The deviation width D1 and the distance L1 are associated with each other on a one-to-one-to-one basis (three-dimensional array data). When the target turning radius R is calculated by the calculation formula, the deviation width D1 obtained from the output of the guide sensor 31 and the distance L1 corresponding to the position of the virtual point P are substituted into the variables of the calculation formula. The target turning radius R may be obtained.

[1-4. Function block]
FIG. 5 is a functional block diagram showing an example of a functional configuration implemented in the control system 1 of the vehicle 10. In order to realize the driving control described above, the control system 1 functionally includes a guide position detection unit 110, a target steering angle calculation unit 120, a steering actuator control unit 130, a motor control unit 140, and brake control. It has a unit 150 and an abnormality detecting unit 160. These functions may be realized by the arithmetic unit 11a of the ECU 11 executing a program stored in the storage device 11b. Not limited to this, each function may be realized by executing a program by another arithmetic unit such as MCU 12.

[1-4-1. Guide position detector]
When the detection area A1 passes through the guide (guide line 7) while the vehicle 10 is traveling, the guide position detection unit 110 sets the position Q1 (see FIG. 2) of the guide line 7 in the detection area A1 to the guide sensor 31. Detect based on output. The guide position detection unit 110 detects the position of the guide line 7 at regular time intervals.

In the present embodiment, the guide sensor 31 outputs a signal corresponding to the magnetic field formed by the current flowing through the guide wire 7 which is the guide. Since the position and strength of the magnetic field depend on the position of the guide wire 7, the guide position detection unit 110 determines the distance between the guide wire 7 and the guide sensor 31 in the detection region A1 based on the signal output by the guide sensor 31. Then, the position Q1 of the guide (guide line 7) in the detection area A1 is detected.

For example, when the guide sensor 31 has a plurality of coils arranged in the left-right direction and these are arranged in the detection region A1, the guide position detection unit 110 is the position of the guide based on the electromotive force generated in each of the plurality of coils. Calculate Q1.

[1-4-2. Target steering angle calculation unit]
The target steering angle calculation unit 120 has a position of a virtual point P (see FIG. 2) defined behind the detection area A1 and a guide position Q1 in the detection area A1 detected by the guide position detection unit 110. The target steering angle θ of the vehicle 10 is calculated based on the above. More specifically, in the target steering angle calculation unit 120, the locus of the virtual point P (target turning locus) due to the traveling of the vehicle 10 passes through the guide position Q1 in the detection region A1 detected by the guide position detection unit 110. The target steering angle θ is calculated so as to be performed. In other words, the target steering angle θ corresponds to the target traveling locus according to the position of the guide Q in the left-right direction of the vehicle 10 and the position of the virtual point P detected based on the output of the guide sensor 31. .. Note that the passage of the target turning locus of the virtual point P through the position Q1 of the guide in the detection region A1 does not necessarily mean that the locus of the virtual point P overlaps the center of the guide line 7, and for example, in a plan view, The target turning locus of the virtual point P may overlap at any position on the upper surface of the guide line 7, or the locus of the virtual point P intersects at least a part of the linearly continuous guide line 7. There may be.

The target steering angle calculation unit 120 specifies a target turning locus according to the position Q1 of the guide in the left-right direction of the vehicle 10 in the detection area A1 detected based on the output of the guide sensor 31 and the position of the virtual point P. The target steering angle θ is calculated based on this value. The target steering angle calculation unit 120 calculates, for example, the radius of the target turning radius (the above-mentioned target turning radius R, see FIG. 3) as a value for specifying the target turning locus, and the target steering is based on the target turning radius R. Calculate the angle θ. In this case, the target steering angle calculation unit 120 has, for example, a deviation width D1 from the center position of the vehicle 10 in the left-right direction to the position Q1 of the guide, and a distance L1 from the detection region A1 to the virtual point P in the front-rear direction of the vehicle 10. Based on the above, the target turning radius R is calculated. Then, the target steering angle θ is calculated based on the target turning radius R calculated in this way. The target steering angle calculation unit 120 calculates, for example, an angle corresponding to the target turning radius R as a target steering angle θ by using the calculation formula and the two-dimensional array data described with reference to FIG.

[1-4-3. Steering actuator control unit]
The steering actuator control unit 130 controls the steering angle (direction of the front wheels 15) by rotating the steering shaft 17a via the actuator (steering actuator) of the steering device 21. Specifically, the steering actuator control unit 130 outputs a command value to the motor drive device 12. The motor drive device 12 supplies electric power according to the command value to the steering actuator to rotate the steering shaft 17a. Further, the steering actuator control unit 130 controls the actual steering angle by outputting to the motor drive device 12 an instruction value corresponding to the target steering angle θ calculated by the target steering angle calculation unit 120.

The steering actuator control unit 130 controls the steering angle so that the actual steering angle approaches the target steering angle θ. That is, the steering actuator control unit 130 controls the steering angle so that the virtual point P passes through the guide position Q1. The steering actuator control unit 130 may change the speed of change of the steering angle according to the current vehicle speed. The steering actuator control unit 130 may control the steering angle so that the steering angle changes gently when the vehicle speed is high, for example.

Further, the steering actuator control unit 130 may execute feedback control that detects the current steering angle (rotation angle of the steering 17) and corrects the target steering angle θ based on the steering angle. For example, the steering actuator control unit 130 detects the current steering angle based on the output from the angle sensor that detects the rotation angle of the steering shaft. Then, the steering actuator may be controlled based on the difference between the steering angle and the target steering angle θ.

[1-4-4. Motor control unit, brake control unit]
The motor control unit 140 controls the vehicle drive motor 22 so that the current vehicle speed approaches the set target vehicle speed. Similarly, the brake control unit 150 controls the brake device 23 so that the current vehicle speed approaches the set target vehicle speed.

The target vehicle speed may be set based on, for example, an RFID reader included in the guide sensor 31 reading information (ID information, etc.) from an RF tag on the road. In this case, the motor control unit 140 and the brake control unit 150 execute control for driving the vehicle 10 or decelerating or stopping the traveling vehicle 10 based on the information read from the RF tag. The setting of the target vehicle speed may be realized by executing the program stored in the storage device 11b by the arithmetic unit 11a of the ECU 11. The ECU 11 (arithmetic unit 11a) has, for example, information read from an RF tag on a traveling path by an RFID reader, information obtained from an outside world sensor 32 (camera, etc.), and an operation state for the vehicle 10 (for example, an operation for an accelerator pedal). Set the target vehicle speed based on the situation). Further, when the target steering angle θ calculated by the target steering angle calculation unit 120 exceeds the threshold value, the target vehicle speed may be reduced. In this case, the motor control unit 140 and the brake control unit 150 execute control for suppressing the speed of the vehicle 10.

[1-4-5. Anomaly detection unit]
The abnormality detection unit 160 detects an abnormality that has occurred in the vehicle 10 based on the states of various mechanisms and devices mounted on the vehicle 10, the detection results of various sensors, and the like. The abnormality detection unit 160 may detect, for example, a situation in which the guide (in the present embodiment, the guide wire 7) is not detected in the detection area A1 as an abnormality. In addition to this, when the target steering angle θ calculated by the target steering angle calculation unit 120 exceeds the threshold value (the target turning radius R is less than the minimum turning radius defined for the vehicle 10), the abnormality detecting unit 160 is used. ), Or when the remaining amount of the battery that supplies electric power to the vehicle drive motor 22 is less than the threshold value, it may be determined as abnormal. As will be described later, as a guide, a marker (for example, a magnetic marker) arranged at regular intervals along the traveling path may be used instead of the guide wire 7. In this case, the abnormality detection unit 160 may detect a situation in which the next marker is not detected after the latest marker is detected and the vehicle travels a predetermined distance as an abnormality.

When the abnormality detection unit 160 detects an abnormality in the vehicle 10, the motor control unit 140 and the brake control unit 150 execute control to stop the running of the vehicle 10. More specifically, when the target vehicle speed is set to zero, the motor control unit 140 stops driving the motor for driving the vehicle 10, and the brake control unit 150 stops the vehicle 10 as a brake device. The braking force of the vehicle 10 is applied to the 23.

[1-5. flowchart]
FIG. 6 is a flow chart showing an example of the automatic traveling process executed by the control system 1. FIG. 7 is a flow chart showing an example of steering angle control processing executed by the control system 1 (particularly, the target steering angle calculation unit 120 and the steering actuator control unit 130).

As shown in FIG. 6, the control system 1 determines whether or not the guide (in the present embodiment, the guide line 7) is detected in the detection area A1 (step S101). The determination in step S101 is performed based on the guide position Q1 detected by the guide position detection unit 110. When it is determined that the guide is detected in the detection area A1 (Yes in step S101), the control system 1 executes the steering angle control process shown in FIG. 7 (step S102).

Proceeding to FIG. 7, the target steering angle calculation unit 120 measures the deviation width D1 in the left-right direction between the center position in the detection region A1 and the guide position Q1 (step S111). Then, the target steering angle calculation unit 120 calculates the target steering angle θ based on the distance L1 in the front-rear direction of the vehicle 10 from the detection region A1 to the virtual point P and the deviation width D1 measured in step S111. Step S112). As described above, the target steering angle calculation unit 120 calculates, for example, a value (target turning radius R) that specifies the target turning locus according to the detected guide position Q1 and the position of the virtual point P. The target steering angle θ is calculated based on this value.

The steering actuator control unit 130 controls the steering angle so that the actual steering angle approaches the target steering angle θ (step S113). As a result, the steering angle is controlled so that the locus of the virtual point P approaches the position Q1 of the guide.

Returning to FIG. 6, when the abnormality detecting unit 160 detects an abnormality in the vehicle 10 (Yes in step S103), the motor control unit 140 and the brake control unit 150 execute control to stop the traveling of the vehicle 10 (step S104). ), End the automatic driving process. In step S103, for example, when the guide line 7 is not detected in step S101, when the guide line 7 is not detected and the vehicle travels a predetermined distance, or when the target steering angle θ calculated in step S112 exceeds the threshold value. (When trying to make a sharp turn) may be determined as abnormal.

When the abnormality is not detected by the abnormality detecting unit 160 (No in step S103), the control system 1 repeats the determination process of whether or not the induction wire 7 in step S101 is detected. In this way, the control system 1 sequentially executes the control of the steering angle according to the position Q1 of the guide and the virtual point P in the detection area A1 until the abnormality of the vehicle 10 is detected.

The control system 1 may read the information recorded on the RF tag embedded in the intersection or the like by the RFID reader of the guide sensor 31. Then, the motor control unit 140 and the brake control unit 150 may control the vehicle drive motor 22 and the brake device 23 according to the information recorded in the RF tag.

[1-6. effect]
8A and 8B are schematic views showing the posture of the vehicle 10 when the vehicle 10 travels along the guide (in this embodiment, the guide line 7). FIG. 8A shows a case where the vehicle 10 has traveled by the conventional travel control, and FIG. 8B shows a case where the vehicle 10 has traveled by the travel control by the control system 1.

As shown in FIG. 8A, when the traveling control is performed so that the central position in the region of the guide sensor 31 arranged along the left-right direction passes through the guide line 7, due to the difference in the inner ring of the vehicle 10, The rear wheel 16 approaches an obstacle on the shoulder of the road. Therefore, the guide line 7 needs to be defined in the traveling path in consideration of such an inner ring difference. In this regard, as shown in FIG. 8B, according to the travel control in the control system 1, a virtual point P is defined behind the detection area A1 which is the detection area of the guide sensor 31, and this virtual point P is the induction power 7. It is controlled to pass over. This makes it easy to secure a distance between the rear wheel 16 and an obstacle on the shoulder of the road. Further, by arranging the virtual point P between the left and right rear wheels 16, the locus of the rear wheels 16 can be made more appropriate.

[2. Second embodiment]
In the first embodiment, an example in which the guide line 7 is embedded along the traveling path as a guide defined on the traveling path has been described. The guide is not limited to this, and may be a plurality of markers embedded in the traveling path to generate a magnetic field, an electromagnetic wave, or the like. Hereinafter, an example (second embodiment) of the embodiment when the marker is used as a guide will be described. Since the hardware configuration in this embodiment is the same as that in the first embodiment, the description thereof will be omitted.

[2-1. Marker detection]
FIG. 9 is a schematic diagram showing an outline of the traveling control executed in the present embodiment. As shown in FIG. 9, in the present embodiment, a plurality of markers 8 are arranged at intervals along the traveling path. In the present embodiment, the marker 8 is, for example, a magnetic marker such as a magnet embedded in a traveling path. Not limited to this, the marker 8 may output an electromagnetic wave.

Further, as shown in FIG. 9, in the present embodiment, as in the first embodiment, the detection region A1 along the left-right direction of the vehicle 10 is defined, and the guide sensor 31 is arranged inside the detection region A1. There is. The guide sensor 31 outputs a signal corresponding to the strength and position of the magnetic field formed by the marker 8 that has reached the detection region A1, that is, a signal corresponding to the position Q1 of the guide. The control system 1 detects the position Q1 of the guide in the detection area A1 based on the signal output from the guide sensor 31. Then, the control system 1 controls the steering device 21 so that the virtual point P passes through the detected marker 8. That is, the control system 1 calculates the target steering angle θ so that the virtual point P passes through the detected marker 8.

[2-2. Change virtual point position]
The position of the virtual point P may be changed according to the driving situation of the vehicle 10. Here, the driving state may be the driving state of the vehicle 10 itself (for example, the vehicle speed) or the environment in which the vehicle 10 is traveling (for example, the state of the traveling path). The environment in which the vehicle 10 is traveling can be detected from the information obtained from the outside world sensor 32 and the information obtained from the RFID reader included in the guide sensor 31.

10A to 10D are schematic views showing an outline of traveling control when the position of the virtual point P is changed in the left-right direction of the vehicle body. As shown in FIG. 10A, when the obstacle O is present on the left side in the traveling direction of the vehicle 10, it becomes necessary to turn the vehicle 10 to the right. In a situation where the obstacle O is detected by the external sensor 32 (for example, a camera), the control system 1 shifts the position of the virtual point P to the position P2 away from the initial position P1 (to the left in FIG. 11A). change. By doing so, it is possible to turn the vehicle 10 to the right.

The vehicle turns to the right from the position of the vehicle 10 shown in FIG. 10A, and then, as shown in FIG. 10B, the position Q1 of the guide (marker 8) is detected at the left end portion of the detection area A1. At this time, the control system 1 starts controlling the steering angle based on the position Q1 of the guide in the detection area A1 and the position of the virtual point P. In FIG. 10B, since the guide position Q1 is located to the left of the vehicle 10 with respect to the virtual point P, the vehicle 10 turns slightly to the left. Also in FIG. 10C, as in FIG. 10B, the vehicle 10 turns slightly to the left, and in FIG. 10D, the steering angle of the vehicle 10 causes the vehicle 10 to go straight. By doing so, the vehicle 10 can travel on the traveling route while avoiding obstacles.

Note that the position of the virtual point P may be changed according to various driving conditions of the vehicle 10, not limited to the appearance of the obstacle O. For example, the position of the virtual point P may be changed to a position to the right of the center position in the left-right direction when the vehicle 10 turns right, or the virtual point P may be changed to a position to the left of the center position when the vehicle 10 turns left. You may. Whether the traveling route of the vehicle 10 will make a left turn or a right turn is determined by, for example, the information (ID information) of the RF tag arranged immediately before the point where the RFID reader included in the guide sensor 31 starts the left turn or the right turn. Etc.), and can be determined by analyzing the image acquired by the camera.

FIG. 10E is a schematic diagram showing an outline of a method of calculating the target steering angle θ when the position of the virtual point P is changed in the left-right direction, and corresponds to FIG. 10A described above. As shown in FIG. 10E, the control system 1 measures the deviation width D1 from the center position of the vehicle 10 to the guide position Q1 in the left-right direction. Then, the control system 1 virtualizes the deviation width D1, the change width ΔD from the position P1 of the virtual point P before the movement to the position P2 of the virtual point P after the movement, and the detection area A1 in the front-rear direction of the vehicle 10. Based on the distance L1 to the point P, the target turning radius R, which is the radius of the turning that the virtual point P should pass, is calculated, and the target steering angle θ is calculated based on this value.

The target turning radius R may be calculated by a predetermined calculation formula having a deviation width D1, a change width ΔD, and a distance L1 as variables, or data stored in advance in a storage device 11b of the ECU 11 or the like ( For example, it may be calculated based on the target turning radius R, the sum of the deviation width D1 and the change width ΔD (D1 + ΔD), and the three-dimensional array data in which the distance L1 is associated with each other on a one-to-one-to-one basis. When the target turning radius R is calculated by the calculation formula, the deviation width D1 and the change width ΔD obtained from the output of the guide sensor 31 and the distance L1 according to the position of the virtual point P are substituted into the variables of the calculation formula. By doing so, the target turning radius R may be obtained.

The movement of the virtual point P is not limited to the left-right direction (vehicle width direction), but may be performed in the front-rear direction of the vehicle 10. For example, the position of the virtual point P may be changed in the front-rear direction of the vehicle 10 according to the vehicle speed. Specifically, when the vehicle speed is higher than the threshold value, the position of the virtual point P may be moved to the rear of the reference position (for example, the position between the left and right rear wheels 16). By doing so, the target steering angle θ becomes small, and the ride quality can be improved.

FIG. 11A is a schematic diagram showing an outline of traveling control when the position of the virtual point P is changed in the front-rear direction of the vehicle 10. As shown in FIG. 11A, by changing the position of the virtual point P to the position P3 behind the initial position P1, the target turning radius R of the vehicle 10 becomes large, and the vehicle 10 turns gently in the left-right direction. Become. That is, the rolling of the vehicle 10 is suppressed, and the riding comfort is improved.

Further, the position of the virtual point P may be moved to the front of the reference position. For example, when the road width of the traveling path is narrow, the position of the virtual point P may be moved ahead of the reference position. By doing so, the target turning radius R of the vehicle 10 becomes small, and the followability of the virtual point P to the change in the position of the guide in the left-right direction is improved. As a result, it is possible to effectively prevent the vehicle body from protruding from the narrow road width of the travel path.

FIG. 11B is a schematic diagram showing an outline of a method of calculating the target steering angle θ when the position of the virtual point P is changed in the front-rear direction of the vehicle 10. As shown in FIG. 11B, the control system 1 measures the deviation width D1 from the center position of the vehicle 10 to the guide position Q1 in the left-right direction. Then, the control system 1 has this deviation width D1, the distance L1 from the detection area A1 in the front-rear direction of the vehicle 10 to the virtual point P before the change, and the virtual point after the change from the position P1 of the virtual point P before the change. Based on the distance ΔL to the position P3 of P, the target turning radius R, which is the radius of turning that the changed virtual point P should pass through, is calculated, and the target steering angle θ is calculated based on this value.

The calculation of the target turning radius R in this case may be calculated by a predetermined calculation formula having the deviation width D1, the distance L1 and the change distance ΔL as variables, or may be stored in advance in the storage device 11b of the ECU 11. Calculated based on the data (for example, the target turning radius R, the deviation width D1, and the three-dimensional array data in which the sum (L1 + ΔL) of the distance L1 and the changed distance ΔL is associated with each other on a one-to-one-to-one basis). May be good. When the target turning radius R is calculated by the calculation formula, the target turning radius is substituted by substituting the deviation width D1 obtained from the output of the guide sensor 31, the distance L1 and the change distance ΔL into the variables of the calculation formula. R may be obtained.

Note that the change in the position of the virtual point P described with reference to FIGS. 10A to 11B may also be executed in the control system 1 of the first embodiment in which the guide line 7 is used as a guide.

[2-3. Function block]
FIG. 12 is a functional block diagram showing an example of a functional configuration implemented in the control system 1 of the present embodiment. In the present embodiment, the guide position detection unit 110 is not the guide line 7, but the marker 8 and the guide sensor 31 in the detection region A1 based on the output of the signal emitted from the guide sensor 31 in response to the magnetic field of the marker 8. The distance is determined, and the position Q1 of the guide (marker 8) in the detection area A1 is detected. Further, in the present embodiment, as shown in FIG. 12, the virtual point position changing unit 210 is added as a function of the control system 1. The virtual point position changing unit 210 may be realized by the arithmetic unit 11a of the ECU 11 executing a program stored in the storage device 11b, or by another arithmetic unit (MCU12 or the like) executing the program. It may be realized.

The virtual point position changing unit 210 changes the position of the virtual point P according to the driving situation of the vehicle 10. More specifically, as described with reference to FIGS. 10A to 10E, 11A, and 11B, the virtual point position changing unit 210 is used in the left-right direction of the vehicle body (vehicle) according to the driving condition of the vehicle 10. The position of the virtual point P is changed in the width direction) or the front-back direction. The "change" here may be performed by selecting a virtual point P according to the driving situation from a plurality of predetermined virtual point P candidates having different positions from each other, or the driving situation of the vehicle 10. The virtual point P may be moved in a direction (rightward, leftward, forwardward, or backwardward) and a distance according to the above. The virtual point position changing unit 210 may move the virtual point P to the outside of the vehicle 10 (to the right, to the left, or to the rear of the vehicle 10).

The virtual point position changing unit 210 may change the changing distance of the virtual point P based on the vehicle speed of the vehicle 10. For example, when the vehicle speed is relatively high, the change distance of the virtual point P may be reduced in the left-right direction. By doing so, if the virtual point P is largely moved in the left-right direction, the rolling motion also increases, so that the rolling motion of the vehicle body can be suppressed.

Similar to the first embodiment, the target steering angle calculation unit 120 has the position of the virtual point P defined behind the detection area A1 and the marker 8 (marker 8 in the detection area A1 detected by the guide position detection unit 110). The target steering angle θ of the vehicle 10 is calculated based on the position Q1 of the guide). More specifically, in the target steering angle calculation unit 120, the locus of the virtual point P (target turning locus) due to the traveling of the vehicle 10 passes through the position Q1 of the marker 8 detected by the guide position detection unit 110. Calculate the target steering angle θ. The target steering angle calculation unit 120 first calculates a value (for example, a target turning radius R) that specifies a target turning locus according to the position Q1 of the guide and the position of the virtual point P, and the target steering is based on this value. The angle θ may be calculated.

When the position of the virtual point P is changed by the virtual point position changing unit 210, the target steering angle calculation unit 120 uses the target steering angle θ based on the position of the virtual point P changed by the virtual point position changing unit 210. Is calculated. The target steering angle calculation unit 120 has, for example, a target turning radius based on the position of the virtual point P changed by the virtual point position changing unit 210 and the position Q1 of the marker 8 detected based on the output of the guide sensor 31. R is calculated, and the target steering angle θ is calculated based on the calculated target turning radius R.

The steering actuator control unit 130 controls the steering angle so that the actual steering angle approaches the target steering angle θ. That is, the steering actuator control unit 130 controls the steering angle so that the virtual point P passes the position Q1 of the guide (marker 8). In the present embodiment, "the virtual point P passes through the guide position Q1" is not necessarily limited to the locus of the virtual point P overlapping the center of the marker 8 in a plan view, and any of the above surfaces of the marker 8 is used. The locus of the virtual point P may overlap with the position.

The steering actuator control unit 130 may execute feedback control. For example, feedback control may be executed between the detection of the marker 8 (described as the marker 82) in which the detection area A1 is located and the detection of the next marker 8 (described as the marker 81). For example, the rotation angle (actual steering angle) of the steering shaft 17a is detected by the rotation angle sensor between the detection of the marker 82 having the detection area A1 and the detection of the next marker 81. The locus of the virtual point P is calculated from the actual steering angle and the current position of the virtual point P. Then, it is determined whether or not the locus passes through the marker 81. Then, when the calculated locus of the virtual point P does not pass through the marker 81, the target steering angle may be corrected based on the difference between the calculated locus of the virtual point P and the marker 81. For example, when the calculated locus of the virtual point P passes outside the marker 8, the target steering angle θ is corrected based on the difference (deviation width) between the locus of the virtual point P and the marker 81 (target steering). The angle θ may be increased by a correction amount corresponding to the deviation width), and the locus of the virtual point P may be brought closer to the marker 81. When the detection area A1 is located between two adjacent markers 8 (in other words, in a section where the target steering angle calculation unit 120 does not calculate a new target steering angle θ based on the position of the marker 8), steering The actuator control unit 130 may perform such feedback control at regular time intervals.

[2-4. flowchart]
FIG. 13 is a flow chart showing an example of the automatic traveling process executed in the present embodiment. FIG. 14A is a flow chart showing an example of the steering angle control process executed in the present embodiment. FIG. 14B is a flow chart showing another example of the steering angle control process.

As shown in FIG. 13, the control system 1 determines whether or not the position of the virtual point P needs to be changed based on the driving condition of the vehicle 10 (step S201). The control system 1 detects, for example, that the external sensor 32 (for example, a camera) detects an obstacle, or that the traveling route is about to make a left turn or a right turn through the RFID reader included in the guide sensor 31. It is determined that the position of the virtual point P needs to be changed in the left-right direction (vehicle width direction) of the vehicle 10. In addition, for example, the control system 1 determines that the position of the virtual point P needs to be changed in the front-rear direction when the vehicle speed of the vehicle 10 or the road width of the traveling path changes. When it is determined that the position of the virtual point P needs to be changed based on the driving condition of the vehicle 10 (Yes in step S201), the virtual point position changing unit 210 shifts the position of the virtual point P left and right according to the driving condition. The change is made in the direction or the front-back direction (step S202).

The guide position detection unit 110 determines whether or not the guide (marker 8 in the present embodiment) is detected in the detection area A1 (step S203). When it is determined that the guide is detected in the detection area A1 (Yes in step S203), the control system 1 executes the steering angle control process in FIG. 14 (step S204).

As shown in FIG. 14, the target steering angle calculation unit 120 measures the deviation width D1 in the left-right direction between the center position in the detection region A1 and the guide position Q1 (step S211). Further, the target steering angle calculation unit 120 acquires a change width ΔD (see FIG. 10B) between the initial position P1 of the virtual point P and the position P2 changed in the left-right direction (step S212). If the virtual point P has not been changed in the left-right direction, the change width ΔD may be 0. Further, the target steering angle calculation unit 120 is from the initial position P1 of the virtual point P. The change distance ΔL (see FIG. 11B) to the changed position P3 in the front-rear direction is acquired (step S213). If the virtual point P has not been changed in the front-back direction, the change distance ΔL may be 0. The target steering angle calculation unit 120 is based on the deviation width D1, the change width ΔD, the distance L1 in the front-rear direction of the vehicle 10 from the detection area A1 to the virtual point P before the change, and the change distance ΔL. Calculate θ (step S214). Then, the steering actuator control unit 130 controls the steering angle so that the actual steering angle approaches the target steering angle θ (step S115).

Returning to FIG. 13, when the abnormality detecting unit 160 detects an abnormality in the vehicle 10 (Yes in step S205), the motor control unit 140 and the brake control unit 150 execute control to stop the traveling of the vehicle 10 (step S206). ), End the automatic driving process. In step S203, for example, when the guide (marker 8 in the present embodiment) is not detected in step S201 and the vehicle travels a predetermined distance, it may be determined that an abnormality has been detected.

Note that the change of the virtual point P is not limited to the example explained here. For example, the virtual point P may be changed only in the left-right direction or the front-back direction, and the virtual point P may be changed in both the left-right direction and the front-back direction. That is, the virtual point P may be changeable in an oblique direction from the initial position.

The control system 1 may read the information recorded on the RF tag embedded in the intersection or the like by the RFID reader of the guide sensor 31 while traveling. Then, the motor control unit 140 and the brake control unit 150 may control the vehicle drive motor 22 and the brake device 23 according to the information recorded in the RF tag.

[2-5. effect]
As described above, in the present embodiment, the marker 8 is adopted instead of the guide line 7 as a guide for defining the traveling route. Even in such a case, the distance between the rear wheel 16 and the obstacle on the shoulder is secured by the virtual point P provided behind the detection area A1 passing through the marker 8 detected in the detection area A1. It will be easier to do. Further, by arranging the virtual point P between the left and right rear wheels 16, the locus of the rear wheels 16 can be made more appropriate.

Further, in the present embodiment, the position of the virtual point P is changed in the left-right direction (vehicle width direction) or the front-rear direction of the vehicle body according to the driving condition of the vehicle 10. For example, by changing the position of the virtual point P in the left-right direction, it is possible to turn the vehicle 10 on the optimum trajectory when it is necessary to avoid obstacles or when it is necessary to turn left or right. can. Further, by changing the position of the virtual point P in the front-rear direction of the vehicle 10, for example, steering suitable for the vehicle speed and steering suitable for the road width become possible.

[3. Third Embodiment]
As shown in FIG. 15, the vehicle 10 may have a first guide sensor 31A and a second guide sensor 31B. The first guide sensor 31A is the same as the guide sensor 31 described in the second embodiment. The second guide sensor 31B is a sensor provided separately from the first guide sensor 31A, and is arranged behind the first guide sensor 31A in the vehicle 10. That is, the detection area A2 of the second guide sensor 31B is defined at a position behind the detection area A1 along the left-right direction of the vehicle 10. The detection area A2 is defined over the right side and the left side with the center in the left-right direction of the vehicle body interposed therebetween. In a plan view, the detection region A2 is located behind the center of the vehicle 10 in the front-rear direction. The detection area A2 is arranged at the same position as the virtual point P in the front-rear direction.

As shown in FIG. 15, when the detection area A2 passes through the marker 82 while the vehicle 10 is traveling, the second guide sensor 31B outputs a signal corresponding to the position Q2 of the marker 82. In the present embodiment, the second guide sensor 31B is the same sensor as the first guide sensor 31A, and outputs a signal corresponding to the position of the magnetic field (position of the marker 8) emitted from the marker 8. The second guide sensor 31B may have a plurality of coils arranged in the left-right direction.

In the third embodiment, the target steering angle calculation unit 120 corrects the target steering angle θ of the vehicle 10 based on the position of the marker 8 detected in the detection area A2 and the position of the virtual point P. Referring to FIG. 15, the target steering angle calculation unit 120 measures, for example, the deviation width between the virtual point P in the left-right direction and the position of the mark 82 in the detection area A2, and determines the target steering angle θ based on this deviation width. to correct. Such correction may be performed when the detection area A1 of the first guide sensor 31A is located between two adjacent markers 8 (between

markers

80 and 82 in FIG. 15). Specifically, when the detection region A1 of the first guide sensor 31A passes through the marker 81, the target steering angle θ1 is calculated based on the position of the marker 81 and the position of the virtual point P at that time, and the actual steering angle θ1 is calculated. The steering device 21 is controlled so that the steering angle becomes the target steering angle θ1. After that, it is detected by the second guide sensor 31B that the detection area A2 of the second guide sensor 31B passes through the marker 82, the virtual point P does not pass through the marker 82, and a deviation width is generated between them. The target steering angle calculation unit 120 corrects the previously calculated target steering angle θ1 based on this deviation width. The target steering angle calculation unit 120 corrects the target steering angle θ1 so that the virtual point P passes through the marker 81, for example. Unlike this, the target steering angle calculation unit 120 may increase or decrease the target steering angle θ1 by an angle according to the deviation width. A calculation formula for performing such a calculation (a formula showing the relationship between the deviation width, the target steering angle θ1 and the corrected target steering angle) may be stored in the storage device 11b.

[4. Fourth Embodiment]
In an example of the control system (for example, the second embodiment described above), the position Q1 of the marker 8 (in other words, the deviation width D1) is detected when the position Q1 of the marker 8 (guide) in the detection area A1 is detected. The target steering angle θ is calculated based on (deviation width D1) and the distance L1 (FIGS. 10B and 11B) from the detection area A1 to the virtual point P, and control for bringing the steering angle closer to this target steering angle θ is started. Rudder. Unlike this, the target steering angle θ according to the relative position between the position at the time after the marker 8 and the virtual point P at the time after the time when the position Q1 of the marker 8 in the detection area A1 is detected. May be calculated to start control of the steering angle toward the target steering angle θ. For example, when a plurality of markers 8 exist between the detection area A1 and the virtual point P, the position of the marker 8 becomes the marker 8 closest to the virtual point when the marker 8 whose position is detected in the detection area A1 becomes the marker 8. It may be calculated based on the deviation width of the above and the distance between the marker 8 closest to the virtual point P and the virtual point P in the front-rear direction.

[4-1. Steering angle control timing]
16A and 16B are schematic views showing an outline of the traveling control executed in the present embodiment. As shown in FIG. 16A, in the present embodiment, as in the second embodiment, a plurality of markers 8 (for example, magnetic markers) are arranged as guides defining the traveling route, and these positions are set as virtual points. The traveling control of the vehicle 10 is performed so that P follows.

Similar to the guide sensor 31 described in the second embodiment, the first guide sensor 31A also outputs a signal according to the position of the guide in the detection area A1. Based on this signal, the control system 1 detects the position Q1 of the marker 8. In the example shown in FIG. 16A, the position Q1 of the marker 8 (referred to as the marker 81) that has reached the detection area A1 is detected. In an example of the control system, at the time when the position Q1 of the marker 81 is detected (the time shown in FIG. 16A; hereinafter referred to as the first time point), the position Q1 of the marker 81 and the virtual point P from the detection area A1. The target steering angle θ is calculated based on the distance L1 to, and the actual steering angle (direction of the front wheel 15) is controlled so that the virtual point P approaches the target steering angle θ. In this case, as shown in FIG. 16A, the marker 8 located between the marker 81 and the virtual point P at the first time point (for example, the marker 8 arranged immediately before the marker 81; hereinafter referred to as the marker 82). ) May not pass through the virtual point P. For example, at the first time point shown in FIG. 16A, the marker 82 near the virtual point P is located in front of the virtual point P, while the position Q1 of the marker 81 in front of the marker 82 is the position Q1 of the vehicle 10. There is a large shift to the right with respect to the center position. At the first time point when the position Q1 of the marker 81 is detected, the target steering angle is calculated based on the distance L1 from the detection area A1 to the virtual point P and the position Q1 of the marker 81, and the steering angle is set to this target steering angle. When moved toward, the virtual point P will pass on the right side of the marker 82.

[4-2. Calculation of target steering angle]
In the fourth embodiment, in order to prevent such a deviation of the locus of the virtual point P, the following processing is performed. At the first time point (time point in FIG. 16A) when the position Q1 of the marker 81 is detected in the detection area A1, the target steering angle θ (θ0, FIG. 16A) based on the position of the marker 8 (for example, the marker 82) detected before that time point. Continue steering control at (see). At the second time point (time point in FIG. 16B) after the first time point, the target steering angle θ (θ1) is calculated based on the relative position between the position Q1 of the marker 81 detected in the detection area A1 and the virtual point P. Then, the control of the steering angle according to the target steering angle θ (θ1) is started. The second time point is a time point when the virtual point P is closer to the marker 81 than the first time point. An example of the second time point is a time point when the vehicle 10 has advanced by a predetermined distance from the position at the first time point. Another example of the second time point is the time when the virtual point P arrives at the marker 82 immediately before the marker 81. The second time point may be a time point when a predetermined time has elapsed from the first time point. Here, the predetermined time may be, for example, a fixed time or a time changed according to the vehicle speed.

The relative positions at the second time point shown in FIG. 16B are the position Q1 of the marker 81 detected in the detection area A1 (the deviation width D1 of the marker 81 detected at the first time point shown in FIG. 16A) and the virtual point P. It can be calculated based on the position and the direction and distance (in other words, the locus of the virtual point P) that the vehicle 10 has traveled from the first time point to the second time point. More specifically, the target steering angle θ (θ1) shown in FIG. 16B can be calculated based on, for example, the following four elements. (I) Position Q1 of the marker 81 detected at the first time point shown in FIG. 16A (shift width D1 of the marker 81 from the center position of the detection region A1 in the left-right direction (vehicle width direction) of the vehicle 10) (ii) first. Distance ΔD (see FIG. 16B) in which the vehicle 10 has moved in the left-right direction between the time point of Distance ΔL that the vehicle 10 traveled in the front-rear direction between the first time point and the second time point The relative position between the virtual point P and the marker 81 at the second time point is obtained based on these four elements. The target steering angle θ (θ1) can be calculated based on this relative position. Specifically, the distance L2 (L1-ΔL) between the virtual point P and the marker 81 in the front-rear direction of the vehicle body and the deviation width D2 (D1-ΔD) between the virtual point P and the marker 81 in the left-right direction of the vehicle body are set. The target steering angle θ (θ1) can be calculated based on this.

The target steering angle θ (θ1) here can also be obtained by calculating the target turning radius R. The target turning radius R may be calculated by, for example, a predetermined calculation formula having the deviation width D2 and the distance L2 as variables, or data stored in advance in the storage device 11b of the ECU 11 (for example, the target turning). It may be calculated based on the three-dimensional array data in which the radius R, the deviation width D2, and the distance L2 are associated with each other on a one-to-one-to-one basis.

The target steering angle θ is not only the position of the virtual point P and the position Q1 of the marker 81 detected in the detection area A1 at the first time point shown in FIG. 16A, but also at the first time point. It may be calculated based on the position of the previously detected marker 8 (eg, marker 82: see FIG. 16A). For example, the position of the marker 82 detected in the detection area A1 is stored in the storage device 11b of the ECU 11, and based on this position, the position Q1 of the marker 81 detected thereafter, and the position of the virtual point P, the position is stored. The target steering angle θ may be calculated. In this case, it may be determined whether or not to use the position of the marker 8 (marker 82 or the like) detected before the marker 81 is detected in the calculation of the target steering angle θ. For example, when a predetermined time has not passed since the position of the marker 82 was detected, or when the virtual point P has not passed the marker 82 (the mileage of the vehicle 10 after the position of the marker 82 is detected is the threshold value). In the following cases), it can be determined that the position of the marker 82 may be used for calculating the target steering angle θ. Also in this way, the target steering angle θ can be calculated so that the virtual point P passes through both the marker 82 and the marker 81. The target steering angle θ may change until the virtual point P reaches the marker 81.

[4-3. Function block]
FIG. 17 is a functional block diagram showing an example of a functional configuration implemented in the control system 1 of the present embodiment. In the present embodiment, as shown in FIG. 17, in the present embodiment, the guide position storage unit 310 is added as a function of the control system 1. The guide position storage unit 310 may be realized by, for example, the storage device 11b of the ECU 11.

The guide position storage unit 310 stores the value of the marker 8 detected by the guide position detection unit 110 at the first time point according to the position Q1 of the marker 8. The value corresponding to the position Q1 of the marker 8 is, for example, the deviation width D1 between the center position of the detection area A1 and the position Q1 of the guide. Not limited to this, the guide position storage unit 310 may store information (coordinate information or the like) indicating the guide position Q1 as a value corresponding to the guide position Q1.

The target steering angle calculation unit 120 acquires a value (for example, a deviation width D1) corresponding to the position Q1 of the marker 8 from those stored in the guide position storage unit 310 at the second time point after the first time point. Then, the target steering angle θ is calculated based on the relative position between the position of the marker 8 detected at the first time point at the second time point and the virtual point P. The second time point is a time point when the virtual point P is closer to the marker 81 than the first time point. An example of the second time point is the time point when the marker closest to the virtual point P becomes the marker 81. The second time point may be a time point when a predetermined time has elapsed from the first time point. Here, the predetermined time may be, for example, a fixed time or a time changed according to the vehicle speed. The target steering angle calculation unit 120 calculates the target turning radius R based on, for example, the above-mentioned four elements (i) to (iv), and calculates the target steering angle θ (θ1) based on the target turning radius R. do. Then, at the second time point, the steering actuator control unit 130 starts controlling the steering device 21 so that the steering angle changes toward the target steering angle θ.

[4-4. flowchart]
FIG. 18 is a flow chart showing an example of the automatic traveling process executed in the present embodiment. FIG. 19 is a flow chart showing an example of the steering angle control process executed in the present embodiment.

As shown in FIG. 18, the control system 1 determines whether or not the position Q1 of the marker 8 is detected in the detection area A1 of the first guide sensor 31A (step S301). When the marker 8 is detected in the detection area A1 (Yes in step S301), the control system 1 sets the center position of the detection area A1 and the position of the guide in the left-right direction as a value indicating the position Q1 of the marker 8 in the detection area A1. The deviation width D1 from Q1 is stored in the guide position storage unit 310 (step S302). The time point at which the position Q1 of the marker 8 is detected in the detection area A1 is the above-mentioned first time point.

The control system 1 determines whether or not the timing for controlling the steering angle using the position of the marker 8 stored in the guide position storage unit 310 has arrived (step S303). That is, the control system 1 determines whether or not the second time point has arrived. In the control system 1, for example, when a predetermined time has elapsed from the first time point (Yes in step S301) when the marker 8 is detected by the first guide sensor 31A, or when the vehicle 10 has traveled a predetermined distance from the first time point. In this case, it is determined that the timing for controlling the steering angle (second time point) has arrived. The second time point may be the time point when the marker closest to the virtual point P becomes the marker 8 stored in the guide position storage unit 310. When it is determined that the timing for controlling the steering angle has arrived (Yes in step S303), the control system 1 executes the steering angle control process shown in FIG. 19 (step S304).

Proceeding to FIG. 19, the control system 1 acquires the deviation width D1 from those stored in the guide position storage unit 310 in step S302 (step S311). Further, the control system 1 calculates the direction and distance (trajectory of the virtual point P) that the vehicle 10 has traveled from the first time point when the marker 8 is detected by the first guide sensor 31A to the present (step S312). In step S312, for example, the distance ΔD (FIG. 16B) in which the vehicle 10 has moved in the left-right direction and the distance ΔL (FIG. 16B) in which the vehicle 10 has moved in the front-rear direction are calculated.

The target steering angle calculation unit 120 is based on the deviation width D1, the distance L1 from the detection area A1 to the virtual point P, and the direction and distance (trajectory of the virtual point P) that the vehicle 10 measured in step S312 has traveled. , The target steering angle θ is calculated (step S313). The target steering angle calculation unit 120 is, for example, based on the value D2 obtained by subtracting the distance ΔD from the deviation width D1 and the value L2 obtained by subtracting the distance ΔL from the distance L1, that is, the second marker 8 detected at the first time point. The target steering angle θ is calculated based on the relative position between the position at the time point 2 and the virtual point P. The steering actuator control unit 130 controls the steering angle so that the actual steering angle approaches the target steering angle θ calculated in step S313 (step S314). As a result, at the second time point after the time point when the guide is detected by the first guide sensor 31A (first time point), the steering angle (direction of the front wheel 15) becomes the target steering angle θ based on the position Q1 of the marker 8. ) Can be started.

Returning to FIG. 18, when an abnormality in the vehicle 10 is detected (Yes in step S305), the control for stopping the running of the vehicle 10 is executed (step S306), and the automatic running process is terminated. In step S305, for example, when the marker 8 travels a predetermined distance without being detected by the first guide sensor 31A, it may be determined that an abnormality has been detected.

[4-5. effect]
As described above, in the fourth embodiment, the position of the marker 8 and the virtual point P are relative to each other at the second time point after the first time point when the first guide sensor 31A detects the guide (marker 8). The target steering angle θ based on the position is calculated. By doing so, as described with reference to FIGS. 16A and 16B, the virtual point P can effectively follow the positions of the plurality of markers 8.

[5. Modification example]
The present invention is not limited to the embodiments described above, and various modifications may be made. For example, in the embodiment, a case where a sensor for detecting magnetism or electromagnetic waves is used as the guide sensor 31 (first guide sensor 31A, second guide sensor 31B) has been described, but the detection of the guide positions Q1 and Q2 is performed. This may be done by using various sensors.

For example, the position Q1 of the marker 8 (guide) may be detected by reading the information (ID information, etc.) of the RF tag embedded in the traveling path as a guide with an RFID reader. That is, the RF tag may be used as the marker 8. In this case, it is possible to use an RFID reader as the guide sensor 31 (first guide sensor 31A, second guide sensor 31B). For example, the RFID reader, which is the guide sensor 31, may measure the signal strength of the RF tag. Then, the guide position detection unit 110 may determine the distance between the guide sensor 31 and the RF tag based on the signal strength of the RF tag measured by the RFID reader, and detect the position Q1 of the marker 8 in the detection area A1. .. Further, for example, the guide sensor 31 may have a plurality of RFID readers arranged in the left-right direction in the detection area A1. In this case, the guide position detection unit 110 may calculate the position Q1 of the marker 8 based on the signal strength of the RF tag detected by each of the plurality of RFID readers. By using the RF tag as the marker 8, the target steering angle θ is calculated based on the relative position between the RF tag embedded in the traveling path and the RFID reader mounted on the vehicle 10, and the target steering angle is calculated. It is possible to control the actual steering angle based on θ and information such as turning left and right read from the RF tag.

In yet another example, the guide may be a plurality of points (waypoints, coordinates) indicating a traveling route defined in the three-dimensional map or the two-dimensional map recorded in the storage device 11b of the ECU 11. In this case, the control system 1 acquires the current position of the vehicle 10 from the data acquired by the external sensor 31 (for example, LiDAR), and detects when the waypoint passes through the detection region A1 defined in the vehicle 10. The passing position of the waypoint in the area A1 (distance from the center in the left-right direction of the vehicle body to the waypoint) is calculated, and the target steering is performed based on the passing position of the waypoint and the position of the virtual point P in the detection area A1. The angle θ may be calculated. That is, the target steering angle θ may be calculated so that the virtual point P defined behind the detection area A1 passes through the waypoint.

Further, also in the first and fourth embodiments, as described as the second embodiment, the position of the virtual point P may be changed in the left-right direction of the vehicle body and / or in the front-rear direction of the vehicle body.

Further, also in the first, second, and fourth embodiments, as described as the third embodiment, the second guide sensor 31B may be attached behind the guide sensor 31. Then, based on the position of the guide in the detection area A2 of the second guide sensor 31B, the position of the guide in the detection area A1 of the guide sensor 31 (first guide sensor 31A), and the position of the virtual point P, the vehicle 10 The steering angle may be controlled.

As described above, in the second embodiment, the position of the virtual point P does not necessarily have to be changed. In this case, the target steering angle θ is based on the position of the marker 8 (the deviation width D1 from the center position in the left-right direction of the vehicle body to the marker 8) and the distance L1 in the front-rear direction from the detection area A1 to the virtual point P. It is calculated (hereinafter referred to as the first calculation process). On the other hand, in the fourth embodiment, the marker 81 is at a second time point (time point of FIG. 16B) after the first time point (time point of FIG. 16A) when the position Q1 of the marker 81 is detected in the detection area A1. The target steering angle θ is calculated based on the relative position between the position at the second time point and the virtual point P (second calculation process). These two calculation processes may be selectively executed.

[6. Conclusion]
(1) As described above, the travel control system 1 is mounted on the vehicle 10 traveling along the guide defined in the travel path. The travel control system 1 detects when the guide sensor 31 that outputs a signal according to the position of the guide and the detection region A1 defined on the vehicle body along the left-right direction of the vehicle body passes through the guide while the vehicle 10 is traveling. The guide position detection unit 110 that detects the position of the guide in the area A1 based on the output of the guide sensor 31, the virtual point P defined behind the detection area A1, and the detection detected by the guide position detection unit 110. It has a target steering angle calculation unit 120 that calculates a target steering angle θ of the vehicle 10 based on the position of the guide in the region A1. Here, for example, a guide wire 7 such as an electric wire, a marker 8 such as a magnetic marker or an RF tag, and a waypoint on a three-dimensional map or a two-dimensional map recorded in the storage device 11b of the ECU 11 are used as guides. Therefore, a magnetic sensor, an RF-ID reader, and LiDAR can be used as the guide sensor 31. According to this system, when the vehicle 10 turns along the traveling path, the locus of the rear wheels 16 can be optimized.

(2) The target steering angle calculation unit 120 calculates the target steering angle θ so that the locus of the virtual point P due to the traveling of the vehicle 10 passes through the guide position in the detection region A1 detected by the guide position detection unit 110. You may. According to this, it is possible to improve the followability of the vehicle 10 with respect to the traveling route.

(3) The guide sensor 31 may be arranged in the detection area A1. The guide sensor 31 may be a sensor that outputs a signal according to the position of the guide in the guide sensor 31 when the guide sensor 31 passes through the guide while the vehicle 10 is traveling. According to this, the position of the traveling path can be detected by using the guide sensor 31.

(4) The guide position detection unit 110 detects the position of the marker 81 detected at the first time point as the position Q1 of the first guide, and the target steering angle calculation unit 120 is the second after the first time point. At the second time point, the target steering angle θ may be calculated based on the relative position between the position Q1 of the first guide and the virtual point P at the second time point. According to this, the virtual point P can be effectively followed by the guide.

(5) The second time point is the time when the vehicle has advanced by a predetermined distance from the position at the first time point, the time when the virtual point P arrives at the marker 82 detected before the marker 81, or the first time point. It may be a time when a predetermined time has elapsed from.

(6) The target steering angle calculation unit 120 determines the target steering angle θ based on the distance L1 from the detection area A1 to the virtual point P and the guide position Q1 in the detection area A1 detected by the guide position detection unit 110. You may calculate.

(7) The travel control system 1 may include a virtual point position changing unit 210 that changes the position of the virtual point P according to the driving situation of the vehicle 10. According to this, the behavior of the vehicle 10 can be appropriately controlled according to the driving condition of the vehicle 10.

(8) The virtual point position changing unit 210 may change the position of the virtual point P in the left-right direction of the vehicle body according to the driving condition of the vehicle 10. According to this, it is possible to appropriately control the behavior of the vehicle when the vehicle 10 turns or turns left or right.

(9) The virtual point position changing unit 210 may change the position of the virtual point P in the front-rear direction of the vehicle body according to the driving condition of the vehicle 10. According to this, it is possible to appropriately control the followability of the vehicle 10 to the traveling path and the riding comfort of the vehicle 10 according to the driving condition of the vehicle 10.

(10) The target turning radius R that specifies the target turning radius θ according to the position of the guide in the left-right direction of the vehicle body detected based on the output of the guide sensor 31 and the position of the virtual point P is calculated, and the target turning radius R is calculated. The target steering angle θ may be calculated based on the target turning radius R corresponding to the above. According to this, the target steering angle can be calculated in consideration of the target turning locus of the vehicle 10.

(11) The travel control system 1 may further include a second guide sensor 31B, which is installed behind the detection area A1 and outputs a signal according to the position of the guide. Further, the travel control system 1 may correct the target steering angle θ based on the output of the second guide sensor 31. According to this, the followability of the vehicle 10 to the traveling route can be improved more effectively.

(12) The steering device 21 has a traveling control system 1, a steering 17, and an actuator for rotating the steering 17. According to the steering device 21, when the vehicle 10 turns along the traveling path, the locus of the rear wheels 16 can be optimized.

(13) The vehicle 10 which is an autonomous driving vehicle has a travel control system 1. According to this, when the vehicle 10 turns along the traveling path, the trajectory of the rear wheel 16 can be optimized.

(14) In the vehicle 10, the virtual point P is arranged between the tires of the left and right rear wheels 16 in a plan view. According to this, when the vehicle 10 turns along the traveling path, the trajectory of the rear wheel 16 can be optimized.

Claims

It is a travel control system installed in a vehicle that travels along a guide specified on the travel path.
The first sensor that outputs a signal according to the position of the guide and
A guide position detecting unit that detects the position of the guide in the area based on the output of the first sensor when the area defined by the vehicle body passes through the guide while the vehicle is traveling along the left-right direction of the vehicle body.
A target steering angle calculation unit that calculates a target steering angle of the vehicle based on a virtual point defined behind the region and the position of the guide in the region detected by the guide position detection unit. Driving control system.
The target steering angle calculation unit calculates the target steering angle so that the locus of the virtual point due to the traveling of the vehicle passes the position of the guide in the region detected by the guide position detection unit. The traveling control system according to 1.
The first sensor is arranged in the region, and is a sensor that outputs a signal according to the position of the guide in the first sensor when the first sensor passes through the guide while the vehicle is traveling. The driving control system described in.
The guide position detecting unit detects the position of the guide detected at the first time point as the position of the first guide, and determines the position of the guide.
The target steering angle calculation unit determines the target steering angle at a second time point after the first time point based on the relative position between the position of the first guide and the virtual point at the second time point. The traveling control system according to claim 1 to be calculated.
The second time point is a time when the vehicle has advanced by a predetermined distance from the position at the first time point, a time point when the virtual point P arrives at the second guide detected before the first guide, or the second time point. The traveling control system according to claim 4, wherein a predetermined time has elapsed from the time point 1.
The target steering angle calculation unit calculates the target steering angle based on the distance from the region to the virtual point and the position of the guide in the region detected by the guide position detection unit according to claim 1. The driving control system described.
The travel control system according to claim 1, further comprising a virtual point position changing unit that changes the position of the virtual point according to the driving situation of the vehicle.
The traveling control system according to claim 7, wherein the virtual point position changing unit changes the position of the virtual point in the left-right direction of the vehicle body according to the driving condition of the vehicle.
The traveling control system according to claim 7, wherein the virtual point position changing unit changes the position of the virtual point in the front-rear direction of the vehicle body according to the driving condition of the vehicle.
The target steering angle calculation unit is
A value for specifying the target turning locus according to the position of the guide in the left-right direction of the vehicle body detected based on the output of the first sensor and the position of the virtual point is calculated.
The traveling control system according to claim 1, wherein the target steering angle is calculated based on a value corresponding to the target turning locus.
It further has a second sensor, which is installed behind the area and outputs a signal according to the position of the guide.
The travel control system according to claim 1, wherein the target steering angle is corrected based on the output of the second sensor.
The driving control system according to claim 1 and
Steering and
A steering device having an actuator for rotating the steering.
An autonomous driving vehicle having the travel control system according to claim 1.
The self-driving vehicle according to claim 13, wherein the virtual point is arranged between the tires of the left and right rear wheels in a plan view.