Vehicle control device and vehicle control method

Abstract

This control device for a vehicle capable of executing a driving support function includes: a lane recognition unit for recognizing a travel lane on which the vehicle travels; a steering control unit for performing steering control so that the vehicle does not deviate from the travel lane recognized by the lane recognition unit; an imaging device for imaging the periphery of the vehicle; a travel information acquisition unit for acquiring road surface information of a road surface on which the vehicle travels from an image captured by the imaging device; a road surface state estimation unit for estimating a road surface state of the road surface on the basis of the road surface information; and a steering control adjustment unit for adjusting a control value of the steering control according to a road surface state of the road surface.

Description

Vehicle control device and vehicle control method

[0001] The present invention relates to a vehicle control device and a vehicle control method.

[0002] In recent years, advanced driver-assistance systems (ADAS) that provide various functions to assist drivers have become widespread. Examples of steering-related driving assistance functions include lane keeping assist (LKA) and adaptive cruise control (ACC).

[0003] Various driving assistance features have been developed with consideration given to passenger comfort and driving stability. For example, Patent Document 1 discloses a configuration that acquires information on snow accumulation, puddles, and road surface μ as the condition of the road surface on which the vehicle is traveling and changes the warning mode accordingly. Furthermore, Patent Document 2 describes a configuration that sets a limit value for a basic current command value to a motor for performing lane keep assist operation based on the motor temperature.

[0004] Japanese Patent No. 5640653 Japanese Patent Application Laid-Open No. 2019-10966

[0005] The condition of the road surface on which a vehicle travels changes depending on the surrounding environment, such as climate and weather. Considering the ride comfort of vehicle occupants and driving stability, the appropriate control value for steering-related driving assistance functions changes depending on the road surface condition, even if the road shape is the same. Therefore, it is necessary to adjust the control value of driving assistance functions depending on the surrounding environment in which the vehicle is traveling.

[0006] The present invention has been devised in view of the above-mentioned problems, and aims to provide an appropriate driving assistance function that takes into account the road surface conditions of the vehicle and improves the assist performance of the vehicle. However, in addition to this object, another object of the present invention is to achieve effects that are derived from the configurations shown in the below-mentioned embodiments of the invention and that cannot be obtained by conventional techniques.

[0007] A vehicle control device according to one embodiment of the present invention has the following configuration: That is, a vehicle control device capable of executing a driving assistance function, comprising: a lane recognition unit that recognizes a driving lane in which the vehicle is traveling, a steering control unit that performs steering control so that the vehicle does not deviate from the driving lane recognized by the lane recognition unit, an imaging device that images the periphery of the vehicle, a driving information acquisition unit that acquires road surface information of a road surface on which the vehicle is traveling from an image captured by the imaging device, a road surface condition estimation unit that estimates a road surface condition of the road surface based on the road surface information, and a steering control adjustment unit that adjusts a control value of the steering control in accordance with the road surface condition of the road surface.

[0008] A vehicle control method according to another embodiment of the present invention has the following configuration: That is, a vehicle control method capable of executing a driving assistance function, comprising: a lane recognition step of recognizing a driving lane in which the vehicle is traveling, a steering control step of executing steering control so that the vehicle does not deviate from the driving lane recognized in the lane recognition step, an imaging step of capturing an image of the periphery of the vehicle, a driving information acquisition step of acquiring road surface information of a road surface on which the vehicle is traveling from an image captured in the imaging step, a road surface condition estimation step of estimating a road surface condition of the road surface based on the road surface information, and a steering control adjustment step of adjusting a control value of the steering control in accordance with the road surface condition of the road surface.

[0009] The present invention makes it possible to provide an appropriate driving assistance function that takes into account road surface conditions, thereby improving the assist performance of the vehicle.

[0010] A schematic diagram showing an example of the configuration of a vehicle according to an embodiment of the present invention. A conceptual diagram for explaining road surface condition estimation according to an embodiment of the present invention. A flowchart related to control of driving assistance according to an embodiment of the present invention. A graph for explaining control values ​​according to an embodiment of the present invention. A graph for explaining control values ​​according to an embodiment of the present invention.

[0011] A vehicle control device and a vehicle control method will be described as embodiments with reference to the drawings. The embodiments described below are merely examples, and are not intended to exclude various modifications or applications of techniques not explicitly described in the following embodiments. The configurations of the present embodiments can be implemented in various modifications without departing from the spirit thereof. Furthermore, they can be selected or combined as needed. Furthermore, in each drawing, the same components are designated by the same reference numerals to indicate their correspondence.

[0012] First Embodiment [Vehicle Configuration] A vehicle 100 to which a control device according to this embodiment can be applied will be described. The vehicle 100 is a hybrid vehicle equipped with an engine 101 as a drive source, a motor 107 (rotating electric machine) for driving, and a generator 102 for generating electricity. Therefore, the vehicle 100 according to this embodiment can be a hybrid electric vehicle (HEV) or a plug-in hybrid electric vehicle (PHEV) capable of external charging or external power supply. In this embodiment, the vehicle 100 is described as a front-wheel drive vehicle, but is not limited thereto. Rear-wheel drive, four-wheel drive, and the like may also be used. Note that the connection relationships and arrangement of the components within the vehicle 100 shown in FIG. 1 are merely examples, and some connections may be omitted or simplified.

[0013] The generator 102 is connected to the engine 101 and can operate independently of the operation of the motor 107. The engine 101 is connected to a drive shaft 104 via an engine clutch 103. When the engine clutch 103 is engaged, power generated by the engine 101 is transmitted to the drive shaft 104. The motor 107 is connected to the drive shaft 104 via a motor clutch 106. When the motor clutch 106 is engaged, power generated by the motor 107 is transmitted to the drive shaft 104. Drive wheels 105 (front wheels) are mounted on the drive shaft 104. Driven wheels 116 (rear wheels) are mounted on an axle 118.

[0014] The vehicle 100 is also provided with an ECU (Electronic Control Unit) 108, which corresponds to the control device according to this embodiment. The ECU 108 is an electronic control device configured as an LSI (Large-Scale Integration) device or an embedded electronic device that integrates, for example, a microprocessor, a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The ECU 108 acquires signals detected by various sensors provided in the vehicle 100 and controls the vehicle 100. In this embodiment, the ECU 108 includes an ADAS-ECU 113, an EPS-ECU 114, and a camera ECU 115 as part of the ECU 108 to realize steering control, which will be described later, as one of the driving assistance functions. In addition to the ADAS-ECU 113, EPS-ECU 114, and camera ECU 115, the ECU 108 may be composed of multiple ECUs according to their functions in order to provide operational control of the vehicle 100, particularly the ADAS function.

[0015] Examples of sensors provided in the vehicle 100 include an acceleration sensor 109, a speed sensor 110, an image sensor 111, and a temperature sensor 112. The acceleration sensor 109 detects the acceleration of the vehicle 100. The speed sensor 110 detects the speed of the vehicle 100. The image sensor 111 is, for example, a camera, and acquires images of the surroundings of the vehicle 100. The temperature sensor 112 acquires temperature information around the vehicle. Note that the sensors are not limited to these, and may also include an accelerator position sensor, a brake sensor, an engine rotation sensor, a battery remaining capacity sensor, a position sensor, and the like. Furthermore, there are no particular limitations on the installation locations of the sensors or the number of sensors installed. For example, depending on the functions provided by the ADAS, the detection values ​​of the various sensors may be commonly used, or separate sensors may be installed for each function. Specific uses of the various data obtained by the sensors according to this embodiment will be described later.

[0016] The engine 101 is an internal combustion engine (gasoline engine or diesel engine) that uses gasoline or diesel as fuel. The operating state of the engine 101 may be controlled by the ECU 108 or by an electronic control device (not shown) separate from the ECU 108. The generator 102 and the motor 107 according to this embodiment are motor-generators that function as both an electric motor and a generator. The motor 107 is a drive source that exchanges electric power with the battery 117, and functions mainly as an electric motor to drive the vehicle 100 and as a generator during regeneration.

[0017] The generator 102 functions as an electric motor (starter) when starting the engine 101, and is driven by engine power to generate electricity when the engine 101 is running. Furthermore, the generator 102 transmits driving force to the drive shaft 104 of the vehicle 100 in a powered state. An inverter (not shown) that converts direct current and alternating current is provided around (or inside) each of the motor 107 and the generator 102. The rotation speeds and operating states (powered operation, regenerative / powered operation) of the motor 107 and the generator 102 are controlled by controlling the inverter (not shown).

[0018] The vehicle 100 can run in a plurality of driving modes, such as EV mode, series mode, parallel mode, etc. These driving modes are selected by the ECU 108 in accordance with the vehicle state, driving state, the driving force required by the driver, etc. Furthermore, the operations of the engine 101, generator 102, and motor 107 are selectively controlled depending on the driving mode.

[0019] An electric power steering (EPS) 120 is connected to the drive wheels 105 (front wheels in this case) to assist steering by a driver via a steering wheel (not shown). The engine 101 and a motor 107 are connected in parallel to the drive wheels 105 via a transaxle (not shown) incorporating multiple gears and clutches. The engine 101 is also connected to a generator 102 via the transaxle (not shown), and power from the engine 101 is also transmitted to the generator 102. The transaxle is a power transmission device that integrates a final drive (final reduction gear) including a differential and a transmission (reduction gear), and incorporates multiple mechanisms that transmit power between a drive source and a driven device.

[0020] The engine clutch 103 is, for example, a wet multi-plate clutch or a dog clutch. Power on the upstream side of the power transmission path (the engine 101 and generator 102 side) of the engine clutch 103 is transmitted to the drive shaft 104 when the engine clutch 103 is engaged (connected), and is cut off when the engine clutch 103 is disengaged (released).

[0021] The motor clutch 106 is, for example, a wet multi-plate clutch or a dog clutch. Power on the upstream side of the power transmission path from the motor clutch 106 (i.e., the driving force of the motor 107) is transmitted to the drive shaft 104 when the motor clutch 106 is engaged, and is blocked when the motor clutch 106 is disengaged.

[0022] The EPS 120 assists the driver in steering under the control of the EPS-ECU 114. In this embodiment, the EPS 120 performs operations related to an assist support function, which will be described later. Inside or around the EPS 120, sensors (not shown) are provided for detecting the steering angle and steering angular velocity used in various controls.

[0023] [Driving Control] In this embodiment, the LKA function will be described as an example of a driving assistance function related to steering operation of the vehicle 100. However, the present invention is not limited to this, and the LKA function may be applied to other functions as long as the steering control described below can be applied. Note that the LKA function uses a known method, and detailed description thereof will be omitted here.

[0024] In this embodiment, when the LKA function is operating, the state of the road surface on which the vehicle 100 is traveling is estimated, and the control value is adjusted accordingly. In this embodiment, as an example of the road surface state, whether or not the road surface is frozen is estimated, and the control amount is adjusted based on the estimation result. If the road surface is frozen, it is expected that the vehicle 100 is likely to slip, so the control value is adjusted so that the traveling of the vehicle 100 is stable.

[0025] The road surface condition is not limited to frozen, and may include predetermined conditions such as dryness, gravel, mud, and puddles, which may affect steering operation. The area including such road surface conditions can be estimated using the detection results of multiple sensors included in the vehicle 100. For example, mud and puddles may be detected using a known area detection method in image recognition. Gravel and road surface irregularities may also be detected by utilizing the detection results of other sensors (not shown) used in the driving assistance function included in the vehicle 100, such as a vibration sensor and LiDAR.

[0026] When a road surface condition that may affect steering operation, such as dryness, gravel, mud, or puddles, is estimated and identified as described above, control may be performed in the same way as for frozen roads.

[0027] The sensors according to this embodiment include an image sensor 111 capable of capturing images of the road surface at least ahead of the vehicle 100 in the direction of travel, and a temperature sensor 112. The image sensor 111 is, for example, a camera, and may be a front camera used to provide the LKA function. The temperature sensor 112 is a sensor capable of detecting the temperature of the road surface. Note that the temperature sensor 112 may be omitted as long as the functions described below can be provided.

[0028] FIG. 2 is a conceptual diagram illustrating the range of the road surface surroundings acquired by the image sensor 111 and the temperature sensor 112. The information acquired by the image sensor 111 and the temperature sensor 112 is collectively referred to as "road surface information." The road surface information may be an image or distribution information depending on the type of sensor. The road surface information 200 shown in FIG. 2A includes a straight road 201 in the forward direction along which the vehicle 100 is traveling. In this embodiment, the road surface condition estimation process (described later) estimates the road surface condition in a predefined region 202 of the road surface information 200. The range of the region 202 may be a fixed value that is set in advance, or may be expanded or reduced depending on, for example, the traveling speed of the vehicle 100. The region 202 may be defined, for example, as the range within which the vehicle 100 can travel within a certain period of time, i.e., the range within which the front wheels or rear wheels of the vehicle 100 can be located while traveling.

[0029] Fig. 2(b) shows another example of a captured image. The road surface information 210 in Fig. 2(b) includes a road 211 that is a curve ahead of the vehicle 100. In the road surface condition estimation process according to this embodiment, the area of ​​the road 211 may be detected from the road surface information 210, and the road surface condition may be estimated based on that area.

[0030] The range of the captured image used in the road surface condition estimation process described later is not limited to the examples shown in Figures 2(a) and 2(b), and may be other ranges. For example, when the function of this embodiment is applied to a driving assistance function that operates when the vehicle 100 is backing up, road surface information behind the vehicle 100 may be acquired and similar control may be performed.

[0031] [Control Flow] Figure 3 is a flowchart of the control process according to this embodiment. This process flow may be implemented by the ECU 108 reading and executing the program and various data according to this embodiment. In this case, in the ECU 108, each ECU that controls each function transmits and receives data to and from each part of the vehicle 100, thereby coordinating with each part and performing control. When this process is performed, it is assumed that the vehicle 100 is in a state where it can run and is running in a running mode that can provide the LKA function. Here, for ease of explanation, the processing entity will be collectively described as the ECU 108.

[0032] In step S301, the ECU 108 starts the LKA function. The LKA function may be started based on an instruction from the driver of the vehicle 100, or may be started automatically when the vehicle 100 enters a predetermined operating mode.

[0033] In step S302, the ECU 108 acquires road surface information captured via the image sensor 111 and the temperature sensor 112. The road surface information corresponds to the information shown in Fig. 2. Here, the ECU 108 may extract from the road surface information an area to be used in the subsequent road surface condition estimation process, as described with reference to Fig. 2.

[0034] In step S303, the ECU 108 estimates the road surface condition based on the road surface information acquired in step S302. In this embodiment, road surface temperature information acquired by the temperature sensor 112 is acquired, and whether the road surface is frozen or not is determined based on the temperature. For example, if the proportion of the area within the area 202 shown in FIG. 2A that is below a predetermined temperature (e.g., 0°C) exceeds a certain threshold, the road surface condition may be determined to be frozen. Alternatively, if at least a portion of the range of the road 211 shown in FIG. 2B is below the predetermined temperature, the road surface condition may be determined to be frozen.

[0035] When identifying a road surface condition other than frozen, for example, detection of a predetermined area such as puddles or mud may be used. In this case, information such as road surface reflection, brightness, contrast, and road surface irregularities may be acquired and used using various sensors.

[0036] If it is determined that the road surface condition is not frozen (NO in step S304), the process by ECU 108 proceeds to step S305. On the other hand, if it is determined that the road surface condition is frozen (YES in step S304), the process by ECU 108 proceeds to step S306.

[0037] In step S305, the ECU 108 switches to a first control mode in the LKA function. An example of the first control mode will be described later. Then, the process of the ECU 108 proceeds to step S307.

[0038] In step S306, the ECU 108 switches to a second control mode in the LKA function. An example of the second control mode will be described later. Then, the process of the ECU 108 proceeds to step S307.

[0039] In step S307, ECU 108 determines whether an instruction to terminate the LKA function has been received. The LKA function may be terminated based on an instruction from the driver of vehicle 100, or may be controlled to be terminated automatically when vehicle 100 reaches a predetermined state. If an instruction to terminate the LKA function has been received (YES in step S307), the processing by ECU 108 proceeds to step S308. On the other hand, if an instruction to terminate the LKA function has not been received (NO in step S307), the processing by ECU 108 returns to step S302 and repeats the processing.

[0040] In step S308, the ECU 108 terminates the LKA function, and then ends this processing flow.

[0041] [Control Example] The first and second control modes of the LKA function according to this embodiment will be described with reference to Figures 4 and 5. In this embodiment, as shown in Figure 3, the control mode is switched depending on the road surface condition. The first control mode is a mode used when the road surface is not frozen, i.e., the road surface condition has little effect on the steering operation. On the other hand, the second control mode is a mode used when the road surface is frozen, i.e., the road surface condition has a large effect on the steering operation. In other words, the second control mode is a control mode defined taking into account slippage due to frozen roads, etc.

[0042] In this embodiment, the second control mode adjusts the steering angular velocity in steering operation to improve driving stability compared to the first control mode. More specifically, the upper limit value for the steering angular velocity in the second control mode is set lower than the upper limit value for the steering angular velocity set for the first control mode. The steering angular velocity is then adjusted to be equal to or lower than this upper limit value. Furthermore, the second control mode adjusts the steering start timing to be earlier compared to the first control mode. For convenience, the description will be based on the first control mode. Note that the terms "first" and "second" used here are used to conveniently distinguish between control modes and are not intended to be interpreted as being limited to fixed control modes.

[0043] 4 is a graph illustrating another example of the relationship between steering angular velocity and vehicle speed in each control mode. In FIG. 4, the vertical axis represents steering angular velocity, and the horizontal axis represents vehicle speed [km / h]. Line 401 represents the upper limit of steering angular velocity in the first control mode. Line 402 represents the upper limit of steering angular velocity in the second control mode.

[0044] 4, the upper limit of the steering angular speed in the second control mode is limited to be lower than that in the first control mode over the entire range of vehicle speeds of the vehicle 100. This is because, when the road surface is icy, if steering control is performed using a high steering angular speed, it is possible that driving stability may be reduced due to slippage or the like.

[0045] 5 is a graph illustrating the relationship between the steering start timing and vehicle speed in each control mode. In FIG. 5, the vertical axis represents the steering start timing, and the horizontal axis represents the vehicle speed [km / h]. Line 501 represents the graph in the first control mode. Line 502 represents the graph in the second control mode. Note that the steering start timing corresponds to the control timing at which steering is started in order to maintain the position of vehicle 100 in the center of the lane in the LKA function, for example.

[0046] As shown in Figure 5, in the second control mode, the steering start timing is controlled to be earlier than in the first control mode over the entire range of vehicle speeds of the vehicle 100. This is because, when the road surface is icy, steering is started at an earlier timing to suppress abrupt changes during turning. As a result, the occurrence of meandering due to slipping or the like on icy road surfaces is suppressed, and driving stability is maintained.

[0047] The adjustment amounts (e.g., upper limits) for the control parameters shown in Figures 4 and 5 are assumed to be specified in advance, but the control values ​​or upper control limits are defined based on the design concept described above. Note that it is not necessary to make all of the steering angular velocity, its upper limit, and steering start timing different between the first control mode and the second control mode. As long as control that takes road surface conditions into consideration can be implemented, a configuration may be adopted in which control is performed for at least one of these items.

[0048] In the present embodiment, as shown in Figures 4 and 5, the steering angular speed, its upper limit, and steering start timing are defined in association with the vehicle speed. These may be defined in advance as a table, or may be defined as a calculation formula that derives the correspondence. Using these, a control value corresponding to the control mode and vehicle speed may be derived.

[0049] In this embodiment, two control modes are switched based on whether the road surface is icy or not. However, this is not limiting, and more control modes may be switchable. For example, a control mode suitable for each road surface condition may be switched depending on the type of estimated road surface condition (e.g., frozen, muddy, puddles, etc.). Alternatively, when the road surface condition is icy, a control mode suitable for the icy condition may be switched depending on the icy level. For example, the icy level may be determined based on the temperature distribution of the road surface. When the icy area is larger, a parameter for executing highly stable steering control is used, assuming a higher icy level.

[0050] As described above, this embodiment makes it possible to provide an appropriate driving assistance function that takes into account road surface conditions, thereby improving the assist performance of the vehicle.

[0051] In the above embodiment, the steering operation has been described assuming an operation by a driver. However, this is not limiting, and the configuration of the present invention may be applied, for example, when an ECU or the like performs a steering operation in a driving assistance function or an autonomous driving function such as an ADAS (Advanced Driver-Assistance Systems) or an ADS (Autonomous Driving System).

[0052] Furthermore, in the present invention, a program or application for realizing the functions of one or more of the above-described embodiments can be supplied to a system or device using a network or a storage medium, etc., and one or more processors in the computer of the system or device can read and execute the program, thereby realizing the present invention.

[0053] As such, the present invention is not limited to the above-described embodiments, and the present invention also contemplates the mutual combination of the various components of the embodiments, as well as modifications and applications by those skilled in the art based on the description in the specification and well-known techniques, and these modifications and applications are included in the scope of protection sought.

[0054] As described above, this specification discloses the following: (1) A control device (e.g., 108) for a vehicle (e.g., 100) capable of executing a driving assistance function, the control device having: a lane recognition unit (e.g., 113) that recognizes the driving lane in which the vehicle is traveling; a steering control unit (e.g., 114) that performs steering control so that the vehicle does not deviate from the driving lane recognized by the lane recognition unit; an imaging device (e.g., 111) that captures images of the periphery of the vehicle; a driving information acquisition unit (e.g., 115) that acquires road surface information of the road surface on which the vehicle is traveling from an image captured by the imaging device; a road surface condition estimation unit (e.g., 114) that estimates the road surface condition of the road surface based on the road surface information; and a steering control adjustment unit (e.g., 113, 114) that adjusts a control value of the steering control in accordance with the road surface condition of the road surface. This configuration makes it possible to provide an appropriate driving assistance function that takes road surface conditions into consideration and improve the assist performance of the vehicle.

[0055] (2) The vehicle control device according to (1), wherein the imaging device has a temperature sensor (e.g., 112) that acquires a temperature distribution of the road surface, and the road surface condition estimation unit estimates whether the road surface is frozen based on the temperature distribution. This configuration makes it possible to estimate the icy state of the road surface based on temperature information about the road surface on which the vehicle is traveling. This also makes it possible to realize safer driving assistance control in accordance with the icy state.

[0056] (3) The vehicle control device according to (2), wherein the road surface condition estimation unit estimates that the road surface is frozen when the ratio of the area below a predetermined temperature in the temperature distribution of the road surface detected by the temperature sensor exceeds a predetermined threshold. This configuration makes it possible to estimate the icy state of the road surface based on the temperature distribution of the road surface on which the vehicle is traveling. This makes it possible to realize safety-oriented driving assistance control in accordance with the icy state.

[0057] (4) The vehicle control device according to (2) or (3), wherein the road surface condition estimation unit estimates that the road surface is frozen when there is an area in the road surface temperature distribution detected by the temperature sensor that is below a predetermined temperature. This configuration makes it possible to estimate the icy state of the road surface based on the temperature distribution of the road surface on which the vehicle is traveling. This makes it possible to realize safety-oriented driving assistance control in accordance with the icy state.

[0058] (5) The vehicle control device according to any one of (2) to (4), wherein the steering control adjustment unit adjusts the upper limit of the steering angular speed to be smaller than a reference value and adjusts the steering start timing to be earlier when it is estimated that the road surface is frozen. With this configuration, when it is estimated that the road surface on which the vehicle is traveling is frozen, it is possible to adjust the control value so as to perform driving assistance control that leans towards safety.

[0059] (6) The vehicle control device according to any one of (1) to (5), wherein the road surface condition estimation unit estimates at least one of puddles, mud, and gravel on the road surface based on the image. This configuration makes it possible to estimate the road surface condition based on an image of the road surface on which the vehicle is traveling. This makes it possible to realize safety-oriented driving assistance control in accordance with the road surface condition.

[0060] (7) The vehicle control device according to (6), wherein the steering control adjustment unit adjusts the upper limit of the steering angular speed to be smaller than a reference value and adjusts the steering timing to be earlier when at least one of a puddle, mud, and gravel area is estimated on the road surface. With this configuration, it is possible to adjust the control value so as to provide safer driving assistance control in accordance with the state of the road surface on which the vehicle is traveling estimated from the image.

[0061] (8) The vehicle control device according to any one of (1) to (7), wherein the driving information acquisition unit further acquires a vehicle speed of the vehicle, and the steering control adjustment unit adjusts the control value based on the vehicle speed. With this configuration, it is possible to adjust the control value based on road surface conditions and vehicle speed so as to provide driving assistance control that leans towards safety.

[0062] (9) A control method for a vehicle (e.g., 100) capable of executing a driving assistance function, the control method for a vehicle comprising: a lane recognition step of recognizing a driving lane in which the vehicle is traveling; a steering control step of executing steering control so that the vehicle does not deviate from the driving lane recognized in the lane recognition step; an imaging step of capturing an image of the periphery of the vehicle; a driving information acquisition step of acquiring road surface information of a road surface on which the vehicle is traveling from an image captured in the imaging step; a road surface condition estimation step of estimating a road surface condition of the road surface based on the road surface information; and a steering control adjustment step of adjusting a control value of the steering control in accordance with the road surface condition of the road surface. This configuration makes it possible to provide an appropriate driving assistance function that takes road surface conditions into consideration, and to improve the assist performance of the vehicle.

[0063] The present invention is applicable to the manufacturing industry of vehicles equipped with driving assistance functions (for example, electric vehicles, hybrid vehicles, and plug-in hybrid vehicles), as well as to the manufacturing industry of control devices installed in vehicles.

[0064] DESCRIPTION OF SYMBOLS 100: Vehicle 101: Engine 102: Generator 103: Engine clutch 104: Drive shaft 105: Drive wheels (front wheels) 106: Motor clutch 107: Motor 108: ECU 109: Acceleration sensor 110: Speed ​​sensor 111: Image sensor 112: Temperature sensor 113: ADAS-ECU 114: EPS-ECU 115: Camera ECU 116: Driven wheels (rear wheels) 117: Battery 118: Axle 120: EPS

Claims

1. A vehicle control device capable of executing a driving assistance function, comprising: a lane recognition unit that recognizes the lane in which the vehicle is traveling; a steering control unit that performs steering control so that the vehicle does not deviate from the lane recognized by the lane recognition unit; an imaging device that captures images of the area around the vehicle; a driving information acquisition unit that acquires road surface information of the road surface on which the vehicle is traveling from images captured by the imaging device; a road surface condition estimation unit that estimates the road surface condition of the road surface based on the road surface information; and a steering control adjustment unit that adjusts a control value of the steering control in accordance with the road surface condition of the road surface.

2. A vehicle control device as described in claim 1, wherein the imaging device has a temperature sensor that acquires the temperature distribution of the road surface, and the road surface condition estimation unit estimates whether the road surface is frozen or not based on the temperature distribution.

3. A vehicle control device as described in claim 2, wherein the road surface condition estimation unit estimates that the road surface is frozen when the proportion of areas below a predetermined temperature in the temperature distribution of the road surface detected by the temperature sensor exceeds a predetermined threshold.

4. A vehicle control device as described in claim 2, wherein the road surface condition estimation unit estimates that the road surface is frozen if there is an area in the temperature distribution of the road surface detected by the temperature sensor that is below a predetermined temperature.

5. A vehicle control device as described in claim 2, wherein the steering control adjustment unit adjusts the upper limit of the steering angular speed to be smaller than the reference value and adjusts the steering start timing to be earlier when it is estimated that the road surface is frozen.

6. A vehicle control device according to claim 1, wherein the road surface condition estimation unit estimates at least one of puddles, mud, and gravel areas on the road surface based on the captured image.

7. A vehicle control device as described in claim 6, wherein the steering control adjustment unit adjusts the upper limit of the steering angular speed to be smaller than the reference value and adjusts the steering timing to be earlier when at least one of a puddle, mud, or gravel area is estimated on the road surface.

8. The vehicle control device according to claim 1, wherein the driving information acquisition unit further acquires a vehicle speed of the vehicle, and the steering control adjustment unit adjusts the control value based on the vehicle speed.

9. A method for controlling a vehicle capable of executing a driving assistance function, comprising: a lane recognition process for recognizing the lane in which the vehicle is traveling; a steering control process for executing steering control so that the vehicle does not deviate from the lane recognized in the lane recognition process; an imaging process for capturing images of the surroundings of the vehicle; a driving information acquisition process for acquiring road surface information of the road surface on which the vehicle is traveling from the image captured in the imaging process; a road surface condition estimation process for estimating the road surface condition of the road surface based on the road surface information; and a steering control adjustment process for adjusting a control value of the steering control in accordance with the road surface condition of the road surface.

Images