Vehicle control system

Abstract

The purpose of the present invention is to provide a vehicle control system capable of preventing complication of the system and reducing water splash when traveling in the vicinity of a puddle without giving a sense of incongruity to a driver. For said purpose, a vehicle control system (100) comprises a rainfall information acquisition unit (130) that acquires rainfall information on a travel path of a vehicle (201). A controller (140) calculates, on the basis of the rainfall information, a water splash risk obtained by quantifying the risk of splashing water when the vehicle (201) travels on the travel path. When the water splash risk is equal to or greater than a prescribed threshold, the controller calculates, as a travel trajectory, a water-splash-reducing travel trajectory (205) in which a normal travel trajectory (204) passing through the center of the travel path is offset to a side of the travel path having a high transverse gradient.

Description

Vehicle Control System

[0001] The present invention relates to a vehicle control system, and more particularly to a vehicle control system that reduces water splashing when driving on a road with puddles.

[0002] In recent years, development of driving assistance controls that assist the driver in driving operations and automatically drive the vehicle has been progressing for automobiles, etc. As vehicle control technologies, technologies that combine a vehicle distance control device and a lane keeping control device to keep the vehicle in the center of the lane, and vehicle control systems that use this type of automatic driving control technology to perform various driving controls to assist the driver in driving operations have been developed.

[0003] In conventional vehicle control systems, various driving control techniques have been proposed to improve the accuracy of driving control and to provide driving support to the driver. One of these techniques is a technique for suppressing water splashing by recognizing puddles on the road surface and performing avoidance control or deceleration control to suppress water splashing. Prior art documents that disclose such techniques include Patent Documents 1 and 2, for example.

[0004] The vehicle control system of Patent Document 1 calculates the amount and height of water splashing based on information (puddle information) such as the position, shape, size, depth, and amount of water of puddles on the road surface, and determines the vehicle control method and control amount so that the amount and height of water splashing are below the allowable upper limit.

[0005] On the other hand, the driving assistance system of Patent Document 2 acquires information about the uneven shape of the road, collects the acquired information about the uneven shape of the road at a management center, digitizes locations where puddles are likely to form, and provides driving assistance based on information about the difference in elevation of the road surface and rainfall information.

[0006] JP 2022-139515 A JP 2010-257307 A

[0007] The vehicle control system of Patent Document 1 requires multiple sensing devices, such as cameras and ultrasonic sensors, to accurately detect puddle information, which results in a complex system. Furthermore, each time the vehicle control system detects a puddle, it performs deceleration control and steering control to avoid the puddle or reduce the amount of water splashing when passing through the puddle. At Level 4 autonomous driving (fully autonomous driving under limited conditions), such control is unlikely to cause discomfort to the driver. However, at Level 2 autonomous driving (assisting the driver's driving operations), such control may cause discomfort to the driver due to driving operations that deviate from the driver's intentions.

[0008] On the other hand, the driving assistance system of Patent Document 2 also requires multiple sensing devices, similar to the vehicle control system of Patent Document 1, which results in a problem of system complexity. Furthermore, the system needs to be equipped with a management center that collects information on the uneven shape of the road and converts information on locations where puddles are likely to form into data, which results in a problem of further system complexity.

[0009] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a vehicle control system device that can prevent the system from becoming complicated and reduce water splashing when driving near puddles without causing discomfort to the driver.

[0010] In order to achieve the above object, the present invention provides a vehicle control system comprising a surrounding information acquisition unit that acquires surrounding information including information about the vehicle's driving path, and a controller that calculates the vehicle's driving trajectory on the driving path based on the information about the driving path and controls the vehicle so that the vehicle drives along the driving trajectory, the vehicle control system further comprising a rainfall information acquisition unit that acquires rainfall information on the driving path, and the controller calculates a water splash risk that quantifies the risk of splashing water when the vehicle drives on the driving path based on the rainfall information, and if the water splash risk is equal to or greater than a predetermined threshold, calculates a water splash reduction driving trajectory as the driving trajectory by offsetting a normal driving trajectory that passes through the center of the driving path to the side of the driving path with a higher cross-gradient.

[0011] According to the present invention, it is possible to prevent the system from becoming complicated and reduce water splashing when driving near a puddle without causing discomfort to the driver.

[0012] 1 is a configuration diagram of a vehicle control system in a first embodiment. FIG. 1 is a plan view showing an overview of water splash reduction control. FIG. 2 is a flowchart showing the processing of a controller related to water splash reduction control in the first embodiment. FIG. 3 is a diagram showing a method for calculating a basic water splash risk value based on wiper information. FIG. 4 is a diagram showing a method for calculating a basic water splash risk value based on a rain sensor output value. FIG. 5 is a diagram showing a method for calculating a basic water splash risk value based on rainfall information. FIG. 6 is a diagram showing a method for calculating a water splash risk correction value based on vehicle speed. FIG. 7 is a diagram showing a method for calculating a water splash risk correction value based on an increase in vehicle weight. FIG. 8 is a diagram showing a method for calculating an offset amount. FIG. 9 is a diagram showing how the offset amount is limited during driver override (when hazard lights are flashing). FIG. 10 is a diagram showing how the offset amount is limited during driver override (when the left turn signal is flashing). FIG. 11 is a diagram showing how the offset amount is limited during driver override (when the driver turns the steering wheel left). FIG. 12 is a diagram showing the road surface shape of a one-way, one-lane road (straight road). FIG. 13 is a diagram showing the road surface shape of a one-way, one-lane road (left-hand turn). FIG. 14 is a diagram showing the road surface shape of a one-way, one-lane road (right-hand turn). FIG. 15 is a diagram showing a method for calculating the cross gradient angle of the road surface. FIG. 1 is a diagram showing an example of a vehicle travel trajectory calculated from a straight road to a left-hand turning circuit. FIG. 2 is a diagram showing an example of a vehicle travel trajectory calculated from a straight road to a right-hand turning circuit. FIG. 3 is a diagram showing another example of a travel trajectory calculated from a straight road to a right-hand turning circuit. FIG. 4 is a diagram showing the relationship between the cross slope angle of the road surface and the offset amount. FIG. 5 is a diagram showing a vehicle travel route when the risk of water splashing is reduced while traveling on a travel trajectory for reducing water splashing. FIG. 6 is a flowchart showing the processing of a controller related to water splash reduction control in a second embodiment.

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each drawing, the same reference numerals are used to designate the same components, and redundant description will be omitted.

[0014] 1 is a configuration diagram of a vehicle control system 100 according to a first embodiment. The vehicle control system 100 includes a surrounding information acquisition unit 110, a vehicle information acquisition unit 120, a rainfall information acquisition unit 130, a controller 140, and an in-vehicle system 150, and is mounted on a vehicle 201 (shown in FIG. 2).

[0015] The surrounding information acquisition unit 110 is configured with a stereo camera, etc. The surrounding information acquisition unit 110 detects surrounding information including white lines and road shoulders ahead of the vehicle 201, and transmits the information to the controller 140.

[0016] The vehicle information acquisition unit 120 is composed of a speed sensor 121, a steering angle sensor 122, a yaw rate sensor 123, an acceleration sensor 124, etc. The speed sensor 121 detects the speed of the vehicle 201 (shown in FIG. 2 ) and transmits it to the controller 140. The steering angle sensor 122 detects the angle of the steering wheel of the vehicle 201, i.e., the steering angle, and transmits it to the controller 140. The yaw rate sensor 123 detects the yaw rate of the vehicle 201 and transmits it to the controller 140. The acceleration sensor 124 detects the longitudinal acceleration and lateral acceleration of the vehicle 201 and transmits it to the controller 140.

[0017] The rainfall information acquisition unit 130 is composed of wipers 131, a rain sensor 132, a communication device 133, etc. The wipers 131 transmit their own operating status to the controller 140. The rain sensor 132 detects water droplets adhering to the vehicle 201 and transmits the information to the controller 140. The communication device 133 receives current or past weather information aggregated in a server or the like and transmits the information to the controller 140.

[0018] Based on information from the speed sensor 121, the steering angle sensor 122, the yaw rate sensor 123, and the surrounding information acquisition unit 110, the controller 140 detects the lane in which the vehicle 201 is traveling, and the yaw angle and lateral position of the vehicle 201 relative to the lane from information about the white lines on the road on which the vehicle 201 is traveling, calculates a steering torque to be applied to the steering of the vehicle 201 so as to generate a yaw moment that causes the vehicle 201 to travel in the center of the lane, and outputs the calculated torque to the steering system 152. Note that although the steering torque is calculated in this embodiment, a target steering angle of the vehicle 201 may be calculated instead.

[0019] The vehicle-mounted system 150 includes an alarm device 151 such as a monitor or buzzer, a steering system 152 , a brake system 153 , and an engine system 154 .

[0020] The notification device 151 outputs a warning or the like to the driver in response to a command from the controller 140 .

[0021] The steering system 152 is configured with an EPS (Electric Power Steering) etc. When there is a possibility that the vehicle 201 may deviate from the road, the steering system 152 generates a yaw moment in the vehicle 201 in response to a command from the controller 140, and generates a steering torque to return the vehicle 201 to the road.

[0022] The brake system 153 is configured with a VDC (Vehicle Dynamic Control) etc. When the vehicle 201 is approaching too close to a vehicle ahead, the brake system 153 generates deceleration in the vehicle 201 in response to a command from the controller 140, thereby reducing the speed of the vehicle 201.

[0023] The engine system 154 generates acceleration in the vehicle 201 in response to a command from the controller 140 .

[0024] The controller 140 uses the steering system 152, the brake system 153, and the engine system 154 to perform a combination of inter-vehicle distance control and lane keeping control, thereby assisting the driver in driving.

[0025] The inter-vehicle distance control is a control for maintaining a distance between the vehicle and the vehicle ahead based on information about the vehicle ahead obtained from the surrounding information acquisition unit 110. The lane keeping control is a function for acquiring information about white lines ahead of the vehicle 201 obtained from the surrounding information acquisition unit 110, and controlling the vehicle 201 in a direction that will prevent the vehicle 201 from deviating from its lane if the vehicle 201 is likely to deviate from its lane. The controller 140 performs a combination of the inter-vehicle distance control and the lane keeping control to maintain a distance between the vehicle and the vehicle ahead and to assist driving so that the vehicle does not deviate from its lane.

[0026] In lane-keeping control, it is desirable to control vehicle 201 so that it stays close to the lane line and stays near the center of the lane, in order to reduce the driver's sense of discomfort from normal driving and the feeling of pressure from vehicles in adjacent lanes. However, depending on the road structure and the deterioration of the road surface, water may accumulate on the road shoulder or in the ruts. Japan's road structure is regulated by the Road Structure Ordinance established by the Ministry of Land, Infrastructure, Transport and Tourism. Article 24 of the Road Structure Ordinance stipulates the cross slope and Article 16 of the road structure ordinance prescribes the lateral road surface slope to guide rainwater that falls on the road surface into gutters or culverts. However, even if a road is constructed according to the prescribed slope, debris, fallen leaves, etc. may accumulate in the gutters, reducing their drainage capacity. In such cases, the drainage treatment system may not function properly, resulting in water accumulating on the road shoulder. Furthermore, given the technical background that requires such structures, the concept of lateral road surface slope is likely to be similar in other countries.

[0027] In addition to road structure, deterioration of the road surface can also make it easier for water to accumulate. This occurs when vehicles drive near the center of the lane, causing the road to deteriorate and leaving ruts at a distance of a vehicle's width from the center. Based on the above, it is thought that areas where water is likely to accumulate during rainfall are generally limited to road shoulders and ruts.

[0028] Therefore, in this embodiment, the travel path is shifted in the vehicle width direction from near the center of the lane, thereby realizing travel that avoids areas where water is likely to accumulate.

[0029] FIG. 2 is a plan view showing an overview of water splash reduction control. The controller 140 calculates a normal driving path 204 that passes through the center of the lane based on information about the road shoulder 202 and the white lines 203 detected by the surrounding information acquisition unit 110. The controller 140 calculates a water splash risk based on rainfall information obtained from the wipers 131 and the rain sensor 132 of the vehicle information acquisition unit 120. The water splash risk is a value that quantifies the possibility that the vehicle 201 will splash water while traveling. If the water splash risk is less than a predetermined threshold, the controller 140 controls the traveling of the vehicle 201 according to the normal driving path 204. If the water splash risk is equal to or greater than the predetermined threshold, the controller 140 calculates a water splash reduction traveling path 205 by offsetting the normal driving path 204 by an offset amount d in a direction away from the road shoulder 202, and controls the traveling of the vehicle 201 according to the water splash reduction traveling path 205. The method for calculating the offset amount d will be described later. By driving the vehicle 201 along such a water splash reduction running track 205, it is possible to prevent the tires from entering areas near the road shoulder 202 where puddles are expected to form or into ruts (expected puddle areas 206), thereby achieving the effect of reducing water splash.

[0030] FIG. 3 is a flowchart showing the processing of the controller 140 relating to the water splash reduction control.

[0031] First, the controller 140 acquires information (driving area information) about the road shoulder 202 and the white lines 203 ahead of the vehicle 201 via the surrounding information acquisition unit 110 (step S101).

[0032] Following step S101, the controller 140 acquires rainfall information via the rainfall information acquisition unit 130 (step S102). The rainfall information here includes, for example, not only the operating status of the wipers 131 and the output value of the rain sensor 132, but also real-time weather information and past weather information acquired via the communication device 133.

[0033] Following step S102, the controller 140 calculates the risk of water splashing based on the rainfall information (step S103). A method for calculating the risk of water splashing will be described below.

[0034] Water splash riskＷＳ is defined as a normalized value between 0 and 1. ＷＳ is the basic value of water splash risk RISK ｂ and water splash risk correction value RISK ｃ is used to calculate using formula (1).

[0035]

[0036] Here, the basic value of splash risk RISK ｂ is a normalized value between 0 and 1, and the water splash risk correction value RISK ｃ is an arbitrary value between 0 and 1. Water splash risk correction value RISK ｃ In situations where there is a high possibility of splashing water, ＷＳ This is a value that can be corrected to increase the water splash risk. ｂ The calculation method will be explained below.

[0037] FIG. 4 shows the basic value RISK of water splash risk based on wiper information. ｂ 1 is a diagram showing a method for calculating the risk base value RISK. ｂ is a value that quantifies how likely a situation is to form a puddle based on current or past rainfall conditions. ｂ is calculated using a signal that can measure the rainfall intensity as an input. For example, the water splash risk base value RISK for the operation state (OFF, LO, MID, HI) of the wiper 131 in the rainfall information is ｂ is set to (0, 0.33, 0.66, 1). Depending on the operation state of the wiper 131, the water splash risk base value RISK ｂ As the water splash risk increases or decreases, the running track frequently switches between the normal running track 204 and the water splash reduction running track 205, which may affect the behavior of the vehicle 201. ｂ When the maximum value is updated, the maximum value may be maintained for a certain period of time thereafter regardless of changes in the operation state of the wiper 131. ｂ Although the relationship between them is shown linearly, the relationship between them may be nonlinear.

[0038] FIG. 5 shows the basic value RISK of the risk of water splashing based on the rain sensor output value. ｂ In this embodiment, the output value (voltage value) of the rain sensor 132 increases as the amount of rain increases. ｂ increases according to the rain sensor output value, and when the rain sensor output value is at its maximum, the water splash risk base value RISK ｂ is set to 1. Note that the rain sensor output value may fluctuate due to noise, so it may be smoothed using a low-pass filter or the like. Also, depending on the change in the rain sensor output value, the water splash risk base value RISK ｂ If the water splash risk base value RISK fluctuates significantly, the running path may frequently switch between the normal running path 204 and the water splash reduction running path 205, which may affect the behavior of the vehicle 201. ｂ In the case where the maximum value is updated, the maximum value may be maintained for a certain period of time thereafter regardless of changes in the rain sensor output value. ｂ Although the relationship between them is shown linearly, the relationship between them may be nonlinear.

[0039] Figure 6 shows the basic value of splash risk RISK based on rainfall information. ｂ 1 is a diagram showing a calculation method of the rainfall information. In this example, the rainfall information is hourly rainfall. The hourly rainfall may be calculated from the current time at the current location or weather information from a certain period of time in the past after the current location is acquired using GPS or the like, or, if the route the vehicle 201 is traveling can be acquired from navigation information or the like, from the current time at the destination or weather information from a certain period of time in the past. In this example, the hourly rainfall and the basic value RISK for splash risk are calculated. ｂ The standard for defining the relationship between the rainfall and the hourly rainfall is the one-hour rainfall defined by the Japan Meteorological Agency. The Japan Meteorological Agency defines an hourly rainfall of 10 mm as moderately heavy rain. Therefore, the basic value for splash risk RISK is 10 mm or more. ｂ The value of RISK is calculated by dividing the hourly rainfall and the splash risk base value RISK by the maximum value of 1. ｂAlso, depending on the change in hourly rainfall, the splash risk base value RISK ｂ If the water splash risk base value RISK fluctuates significantly, the running path may frequently switch between the normal running path 204 and the water splash reduction running path 205, which may affect the behavior of the vehicle 201. ｂ In the case where the maximum value is updated, the maximum value may be maintained for a certain period of time thereafter regardless of changes in the hourly rainfall. ｂ Although the relationship between them is shown linearly, the relationship between them may be nonlinear.

[0040] FIG. 7 shows the water splash risk correction value RISK based on the vehicle speed. ｃ The amount and height of splashed water when the vehicle 201 runs through a puddle increases as the vehicle speed increases. ｃ However, the water splash risk correction value RISK is increased depending on the vehicle speed at the current time. ｃ When the value is continuously changed, the water splash risk base value RISK ｂ Depending on the value of , the vehicle 201 may be swung left and right, which may cause the behavior of the vehicle 201 to become unstable. Therefore, the vehicle speed set by the inter-vehicle distance control device is stored, and while driving is being performed using the inter-vehicle distance control device, the vehicle speed is used as an input to calculate the water splash risk correction value RISK ｃ As shown in FIG. 7, when the vehicle speed exceeds a certain speed (50 km / h), the possibility of splashing water is considered to not increase any more. Therefore, the water splash risk correction value RISK ｃ is kept constant at 1.5.

[0041] FIG. 8 shows the water splash risk correction value RISK based on the increase in vehicle weight. ｃ1 is a diagram showing a method for calculating the water splash risk. When a vehicle 201 runs through a puddle, the amount and height of water splashed increases as the vehicle weight increases. Vehicle weight increases when passengers or cargo are loaded onto the vehicle 201. Therefore, the increase in vehicle weight is estimated from the change in suspension stroke from an unladen state and the relationship between the braking / driving force and acceleration / deceleration of the vehicle 201, and the water splash risk correction value RISK is calculated according to the increase. ｃ However, since the possibility of splashing water does not change until the increase in vehicle weight is ΔW1, the water splash risk correction value RISK ｃ is set constant at 1. On the other hand, if the increase in vehicle weight exceeds ΔW2, it is considered that the possibility of splashing water will not increase any more. Therefore, the water splash risk correction value RISK ｃ is set constant at 1.5. When both the vehicle speed and the increase in vehicle weight are taken into consideration, the calculation methods shown in Figs. 7 and 8 may be combined.

[0042] Returning to FIG. 2, following step S103, the controller 140 determines whether the water splash risk RISK ＷＳ Water splash risk threshold RISK ＴＨ It is determined whether the water splash risk threshold RISK is equal to or greater than the threshold (step S104). ＴＨ is determined based on, for example, the amount of rainfall per hour. When the amount of rainfall per hour exceeds 2 mm, an umbrella is generally needed and there is a possibility of splashing water. Therefore, according to the example shown in FIG. 6, the water splash risk threshold RISK ＴＨ is set to 0.2. Note that the water splash risk threshold RISK ＴＨ may be determined based on the wiper operation state or the rain sensor output value.

[0043] If the determination result in step S104 is No (water splash risk RISK ＷＳ <Water splash risk threshold RISK ＴＨ ), the controller 140 calculates a normal driving path 204 that passes through the center of the lane as the driving path of the vehicle 201 (step S105), and ends the flow. The normal driving path 204 is calculated based on information about the road shoulder 202 and the white lines 203 obtained by the surrounding information acquisition unit 110.

[0044] If the determination result in step S104 is Yes (water splash risk RISKＷＳ ≧ Water splash risk threshold RISK ＴＨ ), the controller 140 calculates the water splash reduction driving track 205, which is the normal driving track 204 offset by the offset amount d, as the driving track of the vehicle 201 (step S106), and ends the flow.

[0045] 9 is a diagram showing a method for calculating the offset amount d. ＷＳ If the water splash risk RISK is high, it is considered that a large amount of water has accumulated near the road shoulder 202. ＷＳ The offset amount d is calculated using equation (2).

[0046]

[0047] Here, the maximum value of the offset amount d is d ｍａｘ is the road width W obtained from the surrounding information acquisition unit 110 Ｒ , the vehicle width W obtained from the vehicle information acquisition unit 120 Ｖ and tire width W Ｔ , and a predetermined margin M, is calculated using equation (3).

[0048]

[0049] Using equations (2) and (3), the water splash risk RISK ＷＳ When the offset value d reaches the maximum value of 1, the offset value d becomes equal to the tire width W Ｔ This allows the vehicle 201 to be kept away from the expected puddle area 206 near the road shoulder 202, thereby reducing splashing of water from puddles formed near the road shoulder 202. In addition, the width of each of the two ruts formed across the center of the lane is equal to the tire width W Ｔ Because the tire width W Ｔ By offsetting the tire by d, it is possible to prevent the tire from entering the rut, thereby reducing the splashing of water from puddles formed in the rut. However, the offset amount d is always set to the tire width W Ｔ If the road width W Ｒ and vehicle width W Ｖ and the maximum value d of the offset amount d according to the margin M from the white line 203.ｍａｘ By limiting the vehicle speed, the vehicle 201 is prevented from deviating from its lane.

[0050] The offset amount d is the water splash risk RISK ＷＳ Regardless of the size of the value, the limit may be imposed when the driver overrides the value. A specific example will be described below.

[0051] 10A to 10C are diagrams illustrating how the offset amount d is limited during driver override. In FIG. 10A, the hazard lights of the vehicle 201 are flashing, indicating the driver's intention to stop the vehicle. In FIG. 10B, the left turn signal is flashing, indicating the driver's intention to turn left. In FIG. 10C, the driver is turning the steering wheel to the left, indicating the driver's intention to move the vehicle 201 to the left. In all of FIGS. 10A to 10C, the driver override condition is met, and the vehicle 201 needs to be moved to the shoulder 202. Therefore, the controller 140 limits the offset amount d to zero and controls the vehicle 201 to travel on the normal driving path 204. The controller 140 monitors the steering speed and steering torque, and determines that the steering wheel has been turned to the left when either signal exceeds a predetermined threshold. When limiting the offset amount d, it is desirable to gradually decrease the offset amount d to 0 after the driver override condition is met. Furthermore, it is desirable to gradually increase the offset amount d from 0 after the driver override condition is released. This helps to prevent sudden changes in vehicle behavior and prevents discomfort to the driver and following vehicles. ＷＳ Water splash risk threshold RISK ＴＨ In addition to the above, the offset amount d may be limited even when the surrounding information acquisition unit 110 detects an oncoming vehicle within a predetermined distance from the vehicle 201. This makes it possible to prevent the vehicle 201 from getting too close to the oncoming vehicle.

[0052] 11A to 11C are diagrams showing the road surface shape of a one-way, single-lane road. Roads are generally designed to have a transverse gradient for efficient drainage. A straight road has a road surface shape with both gradients being highest at the white line in the center of the road, as shown in FIG. 11A. A left-hand turning circuit has a road surface shape with the highest superelevation at the left edge of the road, where the turning radius is large, as shown in FIG. 11B. A right-hand turning circuit has a road surface shape with the highest superelevation at the left edge of the road, where the turning radius is large, as shown in FIG. 11C. By utilizing these characteristics, the controller 140 can estimate whether the potential puddle area 206 is located on the left or right side of the road and determine the direction in which to offset the normal driving trajectory 204.

[0053] 12 is a diagram showing a method for calculating the cross gradient angle of a road surface. In the figure, the cross gradient angle is θ, the gravitational acceleration is g, the vehicle speed is V, the yaw rate is γ, and the lateral acceleration is G. ｙ Here, the cross slope angle θ is positive when the vehicle 201 tilts to the left and negative when the vehicle 201 tilts to the right. ｙ and the centrifugal acceleration Vγ are expressed by the following equation (4).

[0054]

[0055] The cross slope angle θ is calculated from equation (5).

[0056]

[0057] This becomes:

[0058] Here, in order to switch the offset direction of the normal driving trajectory 204 depending on the inclination direction of the road surface, the offset amount d is calculated using equation (6) instead of equation (2). Note that sign θ in equation (6) is a function that returns the sign of the cross slope angle θ.

[0059]

[0060] As a result, if the road surface is inclined to the left, a water splash reduction travel trajectory 205 offset to the right can be calculated, and if the road surface is inclined to the right, a water splash reduction travel trajectory 205 offset to the left can be calculated. Note that in this embodiment, it is assumed that the road is a left-hand traffic road, but if the road is a right-hand traffic road, the offset direction can be reversed.

[0061] 13 is a diagram showing an example of a travel trajectory of a vehicle 201 calculated from a straight road to a left-hand turning circuit. Cross section AA shows the cross section of the straight road, and cross section BB shows the cross section of the left-hand turning circuit. As can be seen from these two cross sections, both the straight road and the left-hand turning circuit are inclined to the left, and therefore an expected puddle area 206 exists on the road shoulder 202 on the left side of the vehicle 201. Therefore, by traveling on a water-splash-reducing travel trajectory 205 that is offset to the right from the normal travel trajectory 204, water splashing can be reduced.

[0062] FIG. 14 is a diagram showing an example of a travel trajectory of a vehicle 201 calculated from a straight road to a right-hand turning circuit. In this example, the sign of the cross slope angle θ of the road surface is not taken into consideration, and a water-splash-reducing travel trajectory 205 offset to the right is calculated as the travel trajectory of the vehicle 201 on both the straight road and the right-hand turning circuit. Cross section AA shows the cross section of the straight road, and cross section BB shows the cross section of the right-hand turning circuit. As can be seen from these two cross sections, the straight road slopes to the left, while the right-hand turning circuit slopes to the right. Therefore, on the straight road, a predicted water puddle area 206 exists near the left shoulder 202, whereas on the right-hand turning circuit, a predicted water puddle area 206 exists near the edge 207 of the opposite lane. As a result, even though there is no predicted water puddle area 206 near the left shoulder 202 on the right-hand turning circuit, the vehicle travels on the water-splash-reducing travel trajectory 205, which has a smaller turning radius than the normal travel trajectory 204. As a result, the lateral acceleration acting on the vehicle 201 increases, which may make it impossible to continue inter-vehicle distance control and lane keeping control. This may also increase the burden on the occupants of the vehicle 201. Therefore, it is desirable to calculate the water splash reduction travel trajectory 205 taking into account the sign of the cross slope angle θ of the road surface.

[0063] 15 is a diagram showing another example of a travel trajectory calculated from a straight road to a right-hand turning circuit. In this example, the water-splash-reducing travel trajectory 205 is calculated taking into account the cross-slope angle θ of the road surface. The controller 140 sets the water-splash-reducing travel trajectory 205, which is offset to the right, as the travel trajectory of the vehicle 201 only when the cross-slope angle θ of the road surface of the vehicle 201 is positive. After the vehicle 201 enters the right-hand turning circuit, because there is no expected water puddle area 206 near the left shoulder 202, the offset amount d is gradually reduced to 0, and the normal travel trajectory 204 is set as the travel trajectory of the vehicle 201.

[0064] 16 is a diagram showing the relationship between the cross slope angle θ of the road surface and the offset amount d. The cross slope angle θ is positive on a straight road or a left-hand turning curve, and negative on a right-hand turning curve. If the offset amount were to be changed in a stepwise manner when the sign of the cross slope angle θ changed, a large lateral acceleration would occur in the vehicle 201, potentially causing the vehicle's behavior to become unstable. To prevent this, the offset amount d is gradually decreased to zero when the cross slope angle θ changes from positive to negative, and is gradually increased from zero when the cross slope angle θ changes from negative to positive.

[0065] 17 is a diagram showing a travel route of the vehicle 201 when the risk of water splashing is reduced while traveling on the water splash reduction travel track 205. ＷＳ Water splash risk threshold RISK ＴＨ If the offset d falls below , the vehicle continues traveling on the water splash reduction traveling track 205 for a predetermined time or a predetermined distance, and then the offset amount d is gradually reduced to zero, and the traveling track is returned to the normal traveling track 204. This prevents the vehicle 201 from swaying from side to side and making the vehicle behavior unstable when, for example, the weather temporarily changes from rainy to sunny and then returns to rainy again, and reduces the sense of discomfort felt by the driver.

[0066] (Summary) In the first embodiment, the vehicle control system 100 includes a surrounding information acquisition unit 110 that acquires surrounding information including information about the road on which the vehicle 201 is traveling, and a controller 140 that calculates the traveling trajectory of the vehicle 201 on the traveling road based on the information about the traveling road and controls the vehicle 201 so that the vehicle 201 travels along the traveling trajectory. The vehicle control system 100 further includes a rainfall information acquisition unit 130 that acquires rainfall information on the traveling road, and the controller 140 calculates a water splash risk RISK that quantifies the risk of the vehicle 201 splashing water when traveling on the traveling road based on the rainfall information. ＷＳ Calculate the water splash risk ＷＳ is a predetermined threshold (water splash risk threshold RISK ＴＨ ) or more, a water splash reduction running track 205, which is obtained by offsetting a normal running track 204 that passes through the center of the running track to the side with a higher cross-slope of the running track, is calculated as the running track.

[0067] According to the first embodiment configured as described above, by having the vehicle 201 travel along the water-splash-reducing travel path 205, which is obtained by offsetting the normal travel path 204 that passes through the center of the roadway toward the side of the roadway with a higher cross-gradient, it is possible to reduce water splashing when traveling near a puddle. Furthermore, since the water-splash-reducing travel path 205 can be calculated without obtaining information such as the position, shape, size, depth, and amount of water of the puddle, it is possible to prevent the vehicle control system 100 from becoming complicated. Furthermore, since the water-splash-reducing travel path 205 has the same shape as the normal travel path 204, excessive deceleration control and steering control are not performed, which makes it possible to prevent the driver from feeling uncomfortable.

[0068] Furthermore, the controller 140 in the first embodiment calculates the offset amount d of the normal running path 204 based on the tire width W of the vehicle 201. Ｔ This makes it possible to minimize the offset amount d of the normal running trajectory 204.

[0069] Furthermore, the controller 140 in the first embodiment calculates a water splash risk RISK based on the amount of precipitation per unit time on the road at the current time or the amount of precipitation on the road from a predetermined time before the current time to the current time. ＷＳ This calculates the water splash risk RISK ＷＳ It is possible to improve the accuracy of the above.

[0070] Furthermore, the controller 140 in the first embodiment is configured to detect the risk of water splashing. ＷＳ changes from the timing when the water splash reduction travel trajectory 205 is calculated as the travel trajectory until the vehicle 201 travels a predetermined distance or until a predetermined time has elapsed, and after the vehicle 201 has traveled the predetermined distance or after the predetermined time has elapsed, the normal travel trajectory 204 is calculated as the travel trajectory. This makes it possible to prevent the vehicle 201 from swaying from side to side and making the vehicle behavior unstable, thereby reducing discomfort felt by the driver.

[0071] Furthermore, the controller 140 in the first embodiment is configured to detect the risk of water splashing. ＷＳ is equal to or greater than the predetermined threshold and a predetermined operation is performed on the vehicle 201, or a water splash risk RISK ＷＳ is equal to or greater than the predetermined threshold and the surrounding information acquisition unit 110 detects an oncoming vehicle within a predetermined distance from the vehicle 201, the traveling path is switched from the water splash reduction traveling path 205 to the normal traveling path 204. This makes it possible to return the traveling path of the vehicle 201 to the normal traveling path 204 in the event of a driver override or when an oncoming vehicle approaches.

[0072] A second embodiment of the present invention will now be described. In the first embodiment, control for reducing splashing of water when traveling on a road with one lane in each direction was described. In the second embodiment, control for reducing splashing of water when traveling on a road with three or more lanes in each direction will be described.

[0073] 18 is a flowchart showing the process of calculating the travel trajectory by the controller 140 in the second embodiment. The following description will focus on the differences from the first embodiment (shown in FIG. 3).

[0074] If the determination result in step S104 is Yes, the controller 140 determines whether the road on which the vehicle 201 is traveling has three or more lanes on each side based on the information obtained from the surrounding information acquisition unit 110 (step S107). At this time, the information for determining the number of lanes may be not only the information obtained from the surrounding information acquisition unit 110 but also map information, GPS information, etc. obtained from the communication device 133.

[0075] If the determination result in step S107 is No, the water splash reduction travel trajectory 205 is calculated within the lane in which the vehicle 201 is traveling (step S106), and the flow ends.

[0076] If the determination result in step S107 is Yes, it is determined whether the vehicle 201 is traveling in the first lane (step S108).

[0077] If the judgment result of step S107 is No (if the vehicle 201 is traveling in the second lane or the third lane), a water splash reduction driving trajectory 205 is calculated within the lane in which the vehicle 201 is traveling (the second lane or the third lane) (step S106), and the flow is terminated.

[0078] If the determination result in step S107 is Yes (if the vehicle 201 is traveling in the first lane), the controller 140 outputs a notification suggesting a lane change from the first lane to the second lane to the HMI 33 (step S109). If the driver receives the notification suggesting a lane change and changes to the second lane, the vehicle 201 can be moved further away from the expected puddle area 206 near the road shoulder 202.

[0079] Following step S109, the controller 140 calculates the water splash reduction travel trajectory 205 in the first lane in which the vehicle 201 is currently traveling (step S106), and ends the flow.

[0080] (Summary) In the second embodiment, the vehicle control system 100 includes a notification device 151 mounted on the vehicle 201, and the controller 140 includes a water splash risk RISK ＷＳ is a predetermined threshold (water splash risk threshold RISK ＴＨ) If the above conditions are met and there is an adjacent lane on the road on which the vehicle 201 is traveling that allows for a lane change, a notification suggesting that the vehicle 201 change lanes to the adjacent lane is output to the alarm device 151.

[0081] The second embodiment configured as described above also provides the same effects as the first embodiment. Furthermore, when a driver receives a notification suggesting a lane change and changes lanes to the second lane, it is possible to further reduce the possibility of splashing water onto a sidewalk or the like adjacent to the first lane.

[0082] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments are presented to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0083] 100...vehicle control system, 110...surrounding information acquisition unit, 120...vehicle information acquisition unit, 121...speed sensor, 122...steering angle sensor, 123...yaw rate sensor, 124...acceleration sensor, 130...rainfall information acquisition unit, 131...wiper, 132...rain sensor, 133...communication device, 140...controller, 150...in-vehicle system, 151...alarm device, 152...steering system, 153...brake system, 154...engine system, 201...vehicle, 202...road shoulder, 203...white line, 204...normal driving track, 205...driving track for reducing splashing, 206...expected puddle area, 207...road edge.

Claims

1. A vehicle control system comprising: a surrounding information acquisition unit that acquires surrounding information including information about the vehicle's driving path; and a controller that calculates the vehicle's driving trajectory on the driving path based on the information about the driving path and controls the vehicle so that the vehicle drives along the driving trajectory, wherein the vehicle control system further comprises a rainfall information acquisition unit that acquires rainfall information on the driving path, and the controller calculates a water splash risk that quantifies the risk of the vehicle splashing water when driving on the driving path based on the rainfall information, and if the water splash risk is equal to or greater than a predetermined threshold, calculates a water splash reduction driving trajectory as the driving trajectory by offsetting a normal driving trajectory that passes through the center of the driving path to the side of the driving path with a higher cross gradient.

2. A vehicle control system according to claim 1, wherein the controller calculates the offset amount of the normal driving path based on the tire width of the vehicle.

3. A vehicle control system as described in claim 1, characterized in that the controller calculates the risk of water splashing based on the amount of precipitation per unit time on the driving path at the current time, or the amount of precipitation on the driving path from a predetermined time before the current time to the current time.

4. A vehicle control system as described in claim 1, wherein the controller calculates the water splash reduction driving trajectory as the driving trajectory from the time when the water splash risk changes from above the predetermined threshold to below the predetermined threshold until the vehicle has traveled a predetermined distance or until a predetermined time has passed, and calculates the normal driving trajectory as the driving trajectory after the vehicle has traveled the predetermined distance or after the predetermined time has passed.

5. A vehicle control system as described in claim 1, characterized in that the controller switches the driving trajectory from the water splash reduction driving trajectory to the normal driving trajectory when the water splash risk is equal to or greater than the predetermined threshold and a predetermined operation is performed on the vehicle, or when the water splash risk is equal to or greater than the predetermined threshold and the surrounding information acquisition unit detects an oncoming vehicle within a predetermined distance from the vehicle.

6. A vehicle control system as described in claim 1, further comprising an alarm device mounted on the vehicle, wherein the controller outputs a notification to the alarm device suggesting a lane change to the adjacent lane when the risk of water splashing is equal to or greater than the predetermined threshold and an adjacent lane into which a lane change is possible exists on the driving path.

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