Steering control system

Abstract

In a steering control system that performs steering control to stabilize a vehicle, the present invention provides a system that can prevent the vehicle from becoming unstable due to crosswinds at the exit of a tunnel. [Solution] The vehicle is configured to calculate a steering correction amount to assist the driver's steering input based on the vehicle's behavior, and to drive the power steering system based on the final steering input obtained by adding the steering correction amount to the driver's steering input. An external server device acquires vehicle class information and steering information, including the steering correction amount at the time of passing through the tunnel exit, from a preceding vehicle that has already passed through the tunnel exit, and stores it in memory according to vehicle class. Then, a subsequent vehicle passing through the tunnel exit acquires the steering information corresponding to its vehicle class from the memory of the external server device, and sets an initial value for the steering correction amount when the vehicle passes through the tunnel exit based on the acquired steering information.

Description

【Technical Field】 【0001】 The present disclosure relates to a steering control system that performs steering control of a vehicle. 【Background Art】 【0002】 Patent Document 1 discloses a technique related to a control device for a vehicle that controls the steering amount so as to achieve both lane keeping performance and steering feeling. In this technique, by controlling the steering amount based on the degree of disturbance such as a crosswind, the vehicle is appropriately lane-kept and the steering feeling of the driver is prevented from deteriorating. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2007-15575 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 According to the technique of Patent Document 1, when a vehicle is affected by a disturbance such as a crosswind, steering control for stabilizing the vehicle is performed. However, at the tunnel exit, it is conceivable that the vehicle suddenly receives a crosswind. In this case, there is a possibility that a delay occurs in the steering control of the vehicle and the vehicle temporarily becomes unstable. 【0005】 The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide a system that can prevent a vehicle from becoming unstable when receiving a crosswind at a tunnel exit in a steering control system that performs steering control for stabilizing the vehicle. 【Means for Solving the Problems】 【0006】 This disclosure applies to a steering control system that controls the steering amount of a vehicle passing through a tunnel exit in order to solve the above problems. The vehicle is configured to calculate a steering correction amount to assist the driver steering amount based on the steering input from the vehicle driver, based on the vehicle's behavior, and to drive the power steering device based on the final steering amount obtained by adding the steering correction amount to the driver steering amount. The steering control system is configured to acquire vehicle class information and steering information including the steering correction amount when passing through the tunnel exit from one or more preceding vehicles that have passed through the tunnel exit before the vehicle, store them in memory according to vehicle class, acquire steering information corresponding to the vehicle class of the vehicle passing through the tunnel exit from the memory, and set an initial value for the steering correction amount when the vehicle passes through the tunnel exit based on the acquired steering information. [Effects of the Invention] 【0007】 The steering control system of this disclosure can prevent the vehicle from becoming unstable due to crosswinds at the exit of a tunnel. [Brief explanation of the drawing] 【0008】 [Figure 1] This is a block diagram illustrating the configuration of the steering control system according to an embodiment of the present disclosure. [Figure 2] This is a flowchart of the steering information collection process performed on the server computer of an external server device. [Figure 3] This figure shows an example of a steering information map that is aggregated during the steering information collection process. [Figure 4] This is a flowchart of the steering correction control performed by the vehicle's onboard computer. [Modes for carrying out the invention] 【0009】 Embodiments of this disclosure will be described below with reference to the drawings. 【0010】 Embodiment. 1. Configuration of the steering control system Figure 1 is a block diagram illustrating the configuration of a steering control system according to an embodiment of the present disclosure. The steering control system 100 comprises an external server device 10 and a vehicle 20 connected to the external server device 10 via a communication network 30. 【0011】 Although not shown in the diagram, the vehicle 20 is equipped with a steering wheel, steering shaft, pinion gear, rack bar, and wheels. The steering wheel is an operating member used by the driver to steer the vehicle. One end of the steering shaft is connected to the steering wheel, and the other end is connected to the pinion gear. The pinion gear meshes with the rack bar. Both ends of the rack bar are connected to the left and right wheels via tie rods. The rotation of the steering wheel is transmitted to the pinion gear via the steering shaft. The rotational motion of the pinion gear is converted into linear motion of the rack bar, thereby changing the steering angle of the wheels. 【0012】 Vehicle 20 is equipped with an electronic power steering (EPS) system. The EPS system is capable of changing the amount of steering input in response to the driver's steering wheel input. More specifically, the EPS system includes an electric motor, which generates assist torque through its rotation. For example, the electric motor is connected to a rack bar via a conversion mechanism. When the rotor of the electric motor rotates, the conversion mechanism converts its rotational motion into linear motion of the rack bar. In this way, the EPS system functions as a power steering system, and the steering torque is assisted by the assist torque. 【0013】 Vehicle 20 is equipped with an on-board computer 21. The on-board computer 21 is a collection of multiple ECUs (Electronic Control Units) mounted on the vehicle 20. Vehicle 20 also includes external sensors 22, internal sensors 23, actuators 24, and a communication device 25. These are connected to the on-board computer 21 using an on-board network such as CAN (Controller Area Network). 【0014】 The in-vehicle computer 21 comprises a processor 21a and a memory 21b coupled to the processor 21a. The memory 21b stores one or more programs 21c that can be executed by the processor 21a and various related information. The memory 21b also stores vehicle class information, including information on the vehicle weight and height of the vehicle 20, and map information. The map information includes road link IDs associated with nodes representing road feature points and road links between nodes. 【0015】 The processor 21a executes program 21c, thereby enabling various processes performed by the processor 21a. Program 21c includes, for example, a program for implementing steering correction control. In steering correction control, the driver steering amount is calculated based on the steering input from the vehicle 20 driver. Furthermore, a steering correction amount is calculated to keep the vehicle 20 in its lane based on the vehicle's behavior due to disturbances such as crosswinds, and the EPS device is driven based on the final steering amount obtained by adding the steering correction amount to the driver steering amount. Details of steering correction control will be described later. 【0016】 The external sensor 22 includes a camera that captures images of the area around the vehicle 20, particularly the area in front. There are no limitations on the type, number, or arrangement of the cameras. The external sensor 22 also includes recognition sensors other than cameras. Recognition sensors are sensors that recognize the surrounding conditions of the vehicle 20. Examples of recognition sensors other than cameras include LiDAR (Laser Imaging Detection and Ranging) and millimeter-wave radar. The external sensor 22 also includes a position sensor that detects the position and orientation of the vehicle 20. An example of a position sensor is a GPS (Global Positioning System) sensor. The information obtained by the external sensor 22 is transmitted to the on-board computer 21 and stored in the on-board computer 21's memory 21b as external sensor information. 【0017】 The internal sensor 23 includes state sensors that acquire information about the motion of the vehicle 20. Examples of state sensors include wheel speed sensors, acceleration sensors, angular velocity sensors, and steering angle sensors. The acceleration sensor and angular velocity sensor may be IMUs. The information obtained by the internal sensor 23 is transmitted to the on-board computer 21 and stored in the memory 21b of the on-board computer 21 as internal sensor information. 【0018】 The actuator 24 includes a steering device for steering the vehicle 20, a drive device for driving the vehicle 20, and a braking device for braking the vehicle 20. The steering device includes the EPS device described above. The actuator 24 is operated by control signals transmitted from the on-board computer 21. 【0019】 The communication device 25 is a device that controls wireless communication with the outside of the vehicle 20. The communication device 25 communicates with the external server device 10 via the communication network 30. The information processed by the in-vehicle computer 21 is transmitted to the external server device 10 using the communication device 25. The information processed by the external server device 10 is taken into the in-vehicle computer 21 using the communication device 25. Also, when a wind direction and wind speed meter is attached to the tunnel exit in the mountainous area where there is a high probability of a crosswind affecting the traveling vehicle, communication for acquiring crosswind information in which the road link ID is associated with the wind direction and wind speed information detected by the wind direction and wind speed meter is also performed by the communication device 25. 【0020】 The external server device 10 includes a server computer 12 and a communication device 14. The server computer 12 is one computer or an aggregate of a plurality of computers connected by a communication network. The server computer 12 includes a processor 12a and a memory 12b coupled to the processor 12a. In the memory 12b, one or more programs 12c executable by the processor 12a and various information related thereto are stored. 【0021】 By the processor 12a executing the program 12c, various processes by the processor 12a are realized. The program 12c includes, for example, a program for realizing a steering information collection process. The steering information collection process is a process of collecting steering information from a plurality of vehicles 20 and mapping it. The steering information collection process will be described later. 【0022】 The communication device 14 is a device that controls communication of the external server device 10 with the outside. The communication device 14 communicates with one or more vehicles 20 via the communication network 30. The information processed by the server computer 12 is transmitted to the vehicle 20 using the communication device 14. The information processed by the vehicle 20 is taken into the server computer 12 using the communication device 14. 【0023】 2. Steering Information Collection Process In the steering information collection process, steering information related to steering correction control is collected from the preceding vehicle passing through the tunnel exit. Figure 2 is a flowchart of the steering information collection process executed on the server computer of the external server device. 【0024】 In step 100, steering information is obtained from vehicles traveling on the road with the road link ID that includes the tunnel exit. The steering information obtained here includes the road link ID corresponding to the travel position, whether or not crosswind information is obtained, the final steering amount and steering correction amount in response to the crosswind, and vehicle class information. Once the processing in step 100 is completed, the process proceeds to step 102. 【0025】 In step 102, the final steering angle and steering angle correction amount are aggregated into a steering information map for each road link ID according to the vehicle class information. Figure 3 shows an example of a steering information map aggregated in the steering information collection process. In the map shown in Figure 3, the final steering angle and steering angle correction amount are aggregated and processed into a map according to the vehicle weight and vehicle height included in the vehicle class information. This routine terminates when the processing in step 102 is completed. 【0026】 Thus, the steering information collection process allows for the real-time collection of steering information in response to crosswinds for each road link ID, including tunnel exits, and associates it with vehicle class information. 【0027】 3. Steering correction control In steering correction control, the driver's steering input is corrected based on changes in the vehicle's behavior determined from internal sensor information. Here, for example, a target steering input is calculated by adding a first target steering input calculated based on vehicle speed and lane radius of curvature, a second target steering input calculated based on vehicle speed and lane offset, and a third target steering input calculated based on vehicle speed and yaw angle relative to the lane. Then, the steering correction amount is calculated by subtracting the driver's steering input from the target steering input. Note that the basic control details of steering correction control are already known from several documents, including Patent Document 1, so a detailed explanation is omitted. 【0028】 According to steering correction control, the vehicle 20's driving can be stabilized by continuously monitoring changes in the vehicle's behavior due to disturbances, etc., and calculating the amount of steering correction. However, for example, when the vehicle 20 is driving through the exit of a tunnel in a mountainous area where there is a high probability of crosswinds that could affect the vehicle, it may be hit by a sudden crosswind. In this case, conventional steering correction control may be delayed, potentially causing the vehicle 20 to become temporarily unstable. 【0029】 Therefore, in the steering correction control of this embodiment, when the vehicle 20 passes through the tunnel exit, the initial value of the steering correction control is set based on the information of the final steering angle and steering angle correction amount of the preceding vehicle that has passed through the tunnel exit. This process is also referred to as the "crosswind response process" below. Figure 4 is a flowchart of the steering correction control performed in the vehicle's onboard computer. 【0030】 In step 110, while the vehicle 20 is traveling on a road with a road link ID that includes the tunnel exit, steering information corresponding to the same road link ID as the vehicle is currently traveling on is obtained from the external server device 10. Here, whether or not crosswind information is obtained, the vehicle height and weight of the vehicle 20, and the final steering amount and steering correction amount corresponding to the road link ID being traveled on are obtained from the steering information map stored in the server computer 12. Once the processing in step 110 is complete, the process proceeds to step 112. 【0031】 In step 112, it is determined whether the final steering angle obtained in step 110 is greater than a predetermined value X. Here, the predetermined value X is a threshold for determining whether crosswind compensation processing is necessary in steering correction control, and a pre-set value is read. If the determination is not met, it is determined that crosswind compensation processing in steering correction control is unnecessary, and the process proceeds to step 122. On the other hand, if the determination is met, it is determined that crosswind compensation processing is necessary in steering correction control, and the process proceeds to step 114. 【0032】 In step 114, the initial value of the steering correction amount in the steering correction control is set to the steering correction amount obtained in step 110. Once the processing in step S114 is completed, the process proceeds to step S116. 【0033】 In step 116, based on internal sensor information, it is determined whether the vehicle 20 has detected vehicle instability due to crosswinds at the tunnel exit. If the determination is not met, it is determined that crosswind countermeasures are not necessary, and the process proceeds to step 122. On the other hand, if the determination is met, it is determined that crosswind countermeasures are necessary, and the process proceeds to step 118. 【0034】 In step 118, the initial value of the steering correction amount set in step 114 is reflected in the steering correction control. Once the processing in step 118 is complete, the process proceeds to step 120. In step 120, steering correction control with crosswind handling is performed. Once the processing in step 120 is complete, the process proceeds to step 122. 【0035】 In step 122, steering information from the steering correction control performed in step 120 is transmitted to the external server device 10. The steering information transmitted here includes the road link ID, whether or not crosswind information was acquired, the final steering amount and steering correction amount in response to the crosswind, and vehicle class information. This information sent to the external server device 10 is aggregated into a steering information map by the steering information collection process shown in Figure 2 and used for steering correction control of following vehicles. Once the processing in step 122 is completed, this routine is terminated. 【0036】 As described above, according to the steering control system 100 of this embodiment, steering information of a preceding vehicle of the same vehicle class passing through the tunnel exit is used to set the initial value for the steering correction control of a following vehicle passing through the tunnel exit. This prevents the vehicle from becoming unstable even if it encounters a sudden crosswind at the tunnel exit. [Explanation of Symbols] 【0037】 10 External server device 12 server computers 12a processor 12b memory 12c program 14. Communication equipment 20 vehicles 21. Onboard computer 21a Processor 21b Memory 21c Program 22 External sensors 23 Internal Sensors 24 Actuators 25 Communication equipment 30 Communication Networks 100 Steering Control System

Claims

[Claim 1] A steering control system that controls the amount of steering input for a vehicle passing through a tunnel exit, The vehicle is configured to calculate a steering correction amount to assist the driver's steering input based on the vehicle's behavior, and to drive the power steering system based on the final steering amount obtained by adding the steering correction amount to the driver's steering input. The steering control system is From one or more preceding vehicles that passed the tunnel exit before the aforementioned vehicle, vehicle class information and steering information including the steering correction amount when passing the tunnel exit are acquired and stored in memory according to vehicle class. The steering information corresponding to the vehicle class of the vehicle passing through the tunnel exit is obtained from the memory, Based on the acquired steering information, the initial value of the steering correction amount when the vehicle passes the tunnel exit is set. A steering control system configured in such a way.

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