Vehicle control device

Abstract

A vehicle control device 100 comprises a driving assistance unit 124 that executes steering assistance control for adjusting steering torque so that a vehicle 10 travels along a set travel trajectory, and travel assistance control for adjusting driving force and braking force so that a vehicle body speed follows a set first set speed. When the steering assistance control cannot be continued while the vehicle 10 is traveling on a curve, the driving assistance unit 124 executes, instead of the travel assistance control, specific control for applying braking force to wheels 11 on the basis of travel information indicating a travel state of the vehicle 10 within a range in which the travel of the vehicle 10 can be continued.

Description

Vehicle control apparatus

[0001] The present invention relates to a vehicle control apparatus.

[0002] Patent Document 1 describes a vehicle control apparatus that performs steering assist control by controlling a steering actuator of an electric power steering apparatus. The steering assist control is control that adjusts steering torque applied by the steering actuator to a steering mechanism in accordance with, for example, the curvature of a road surface on which the vehicle travels.

[0003] Japanese Unexamined Patent Publication No. 2001-10518

[0004] When the vehicle is traveling around a curve and the above-described vehicle control apparatus becomes unable to continue steering assist control for any reason, there is a risk that the vehicle control apparatus cannot appropriately adjust the steering torque applied to the steering mechanism.

[0005] The vehicle control apparatus is applied to a vehicle including: a steering actuator that applies steering torque to a steering mechanism; a traveling actuator that applies driving force to wheels; and a braking actuator that applies braking force to the wheels. The vehicle control apparatus comprises a driving support unit that executes: steering assist control for adjusting the steering torque such that the vehicle travels along a set traveling track; and traveling support control for adjusting the driving force and the braking force such that a vehicle body speed follows a set first set speed. When the vehicle is traveling around a curve and the driving support unit becomes unable to continue the steering assist control, the driving support unit executes specific control instead of the traveling support control, the specific control causing the braking force to be applied to the wheels based on traveling information indicating a traveling state of the vehicle within a range in which traveling of the vehicle can be continued.

[0006] The vehicle control apparatus that solves the above problem can appropriately assist traveling of the vehicle during a transition period from steering assist control to manual steering by a driver while the vehicle is traveling around a curve.

[0007] FIG. 1 is a schematic diagram of a vehicle including the vehicle control apparatus. FIG. 2 is a flowchart explaining the flow of processing executed by the vehicle control apparatus in FIG. 1. FIG. 3 is a schematic diagram showing a state where the vehicle of FIG. 1 is traveling around a curve.

[0008] Hereinafter, an embodiment of a vehicle equipped with a vehicle control device will be described with reference to the drawings. <Vehicle Configuration> As shown in Figure 1, the vehicle 10 is equipped with a plurality of wheels 11, a drive device 20, a braking device 30, a steering device 40, an operating system 50, a detection system 60, a monitoring system 70, a navigation device 80, and a vehicle control device 100.

[0009] Although not shown in Figure 1, the multiple wheels 11 have two front wheels FL and FR and two rear wheels RL and RR. The two front wheels FL and FR are the left front wheel FL and the right front wheel FR, and the two rear wheels RL and RR are the left rear wheel RL and the right rear wheel RR. The left front wheel FL and the left rear wheel RL correspond to the "left wheels," and the right front wheel FR and the right rear wheel RR correspond to the "right wheels." Hereafter, when the vehicle 10 is traveling on a curve, the wheels 11 located on the inside will be called the turning inner wheels, and the wheels 11 located on the outside will be called the turning outer wheels.

[0010] The drive unit 20 includes a motor generator 21 that functions as a power source for the vehicle 10, and a drive control unit 22 that controls the motor generator 21. The vehicle 10 moves by applying the driving force of the motor generator 21 to the wheels 11. The drive unit 20 only needs to have at least one of the following: a motor generator 21 for the front wheels FL and FR that applies driving force to the front wheels FL and FR, and a motor generator 21 for the rear wheels RL and RR that applies driving force to the rear wheels RL and RR. The motor generator 21 corresponds to a "driving actuator". In other embodiments, the drive unit 20 may also include an internal combustion engine as a power source for the vehicle 10. The drive control unit 22 is a processing circuit having a CPU and memory. The drive control unit 22 adjusts the driving force applied to the wheels 11 by controlling the motor generator 21.

[0011] The braking device 30 comprises the same number of braking mechanisms 31 as the number of wheels 11, a braking actuator 32 that drives the multiple braking mechanisms 31, and a braking control unit 33 that controls the braking actuators 32. Each braking mechanism 31 includes a rotating body 311, a friction material 312, and a wheel cylinder 313. When WC pressure, which is the hydraulic pressure inside the wheel cylinder 313, is generated, the friction material 312 is pressed against the rotating body 311, which rotates integrally with the wheel 11. This applies a braking force to the wheel 11. In other words, the higher the WC pressure, the greater the force pressing the friction material 312 against the rotating body 311, and as a result, the greater the braking force. The braking actuator 32 has a brake fluid supply source such as an electric pump or electric cylinder. The braking actuator 32 is connected to the multiple braking mechanisms 31 via a brake fluid passage. The braking control unit 33 is a processing circuit having a CPU and memory. The braking control unit 33 individually adjusts the WC pressure in multiple wheel cylinders 313 by controlling the braking actuator 32.

[0012] The steering system 40 includes a steering mechanism 41 that changes the steering angle of the wheels 11, a steering actuator 42 that applies steering torque to the steering mechanism 41, and a steering control unit 43 that controls the steering actuator 42. When the steering actuator 42 applies steering torque to the steering mechanism 41, the steering angle of the wheels 11 is adjusted. The vehicle 10 turns when the steering angle of the wheels 11 is adjusted while the vehicle 10 is in motion. The steering system 40 only needs to include at least one of the steering actuators 42 for the front wheels FL and FR that adjust the steering angle of the front wheels FL and FR, and the steering actuators 42 for the rear wheels RL and RR that adjust the steering angle of the rear wheels RL and RR. The steering control unit 43 is a processing circuit having a CPU and memory. The steering control unit 43 adjusts the steering torque that the steering actuator 42 applies to the steering mechanism 41 by controlling the steering actuator 42.

[0013] <Operation System, Detection System, Monitoring System, and Navigation Device> The operation system 50 is operated by the driver to drive the vehicle 10. The operation system 50 includes a drive operation member 51, a brake operation member 52, and a steering member 53. The drive operation member 51 is operated by the driver when applying driving force to the vehicle 10. An example of the drive operation member 51 is the accelerator pedal. The brake operation member 52 is operated by the driver when applying braking force to the vehicle 10. An example of the brake operation member 52 is the brake pedal. The steering member 53 is operated by the driver when turning the vehicle 10. An example of the steering member 53 is the steering wheel.

[0014] The detection system 60 detects state quantities that indicate the motion state of the vehicle 10 as it is moving. The detection system 60 includes an accelerator sensor 61, a brake sensor 62, a steering sensor 63, wheel speed sensors 64 (the same number as the wheels 11), a longitudinal acceleration sensor 65, a lateral acceleration sensor 66, and a yaw rate sensor 67. The accelerator sensor 61 detects the amount of operation of the drive operating member 51 by the driver. The brake sensor 62 detects the amount of operation of the braking operating member 52 by the driver. The steering sensor 63 detects the direction and amount of operation of the steering member 53 by the driver. The multiple wheel speed sensors 64 each detect the wheel speed of the multiple wheels 11. The longitudinal acceleration sensors 65 detect the longitudinal acceleration of the vehicle 10. The lateral acceleration sensor 66 detects the lateral acceleration of the vehicle 10. The yaw rate sensor 67 detects the yaw rate of the vehicle 10. The detection system 60 outputs a signal to the vehicle control device 100 according to the detection result.

[0015] The monitoring system 70 monitors the external conditions of the vehicle 10. For example, the monitoring system 70 includes an imaging device 71, a radar 72, and a GPS receiver 73. The imaging device 71 captures images of the area outside the vehicle 10. The imaging device 71 captures images of other vehicles and obstacles in the direction of travel of the vehicle 10. The radar 72 detects the distance from the vehicle 10 to other vehicles, the distance from the vehicle 10 to obstacles, and the distance from the vehicle 10 to pedestrians. The GPS receiver 73 acquires the current location of the vehicle 10. The monitoring system 70 outputs information corresponding to the monitoring results to the vehicle control device 100.

[0016] The navigation device 80 stores map data. The map data includes information on the road network, the shape of the roads that make up the network, and information on speed limits. The navigation device 80 may be an in-vehicle navigation device or an application that runs on a mobile device such as a smartphone. The navigation device 80 outputs information based on the map data to the vehicle control device 100.

[0017] <Vehicle Control Configuration> The vehicle control device 100 is a processing circuit 110 having a CPU 111 and a memory 112. The memory 112 of the vehicle control device 100 stores multiple programs to be executed by the CPU 111 of the vehicle control device 100. By the CPU 111 executing the programs, the vehicle control device 100 functions as multiple functional units. The multiple functional units of the vehicle control device 100 include an acquisition unit 121, a track generation unit 122, a trajectory generation unit 123, a driving support unit 124, and a determination unit 125. The vehicle control device 100 is also communicatively connected to a drive control unit 22, a braking control unit 33, a steering control unit 43, an operation system 50, a detection system 60, a monitoring system 70, and a navigation device 80 via an in-vehicle network such as a CAN.

[0018] The acquisition unit 121 acquires various types of information from the detection system 60. The acquisition unit 121 also calculates the vehicle speed based on the speeds of multiple wheels. Furthermore, the acquisition unit 121 calculates the slip ratio of multiple wheels 11 based on the speeds of multiple wheels and the vehicle speed. The wheel speed, longitudinal acceleration, lateral acceleration, and yaw rate, which are the detection results of the detection system 60, and the vehicle speed and slip ratio calculated from the detection results of the detection system 60 are state quantities that indicate the motion state of the vehicle 10. On the other hand, the information output from the monitoring system 70 and the information output from the navigation device 80 are not state quantities that indicate the motion state of the vehicle 10. Hereafter, the state quantities that indicate the motion state of the vehicle 10 described above will be referred to as "driving information" that indicates the driving state of the vehicle 10.

[0019] The acquisition unit 121 acquires various information from the detection system 60, the monitoring system 70, and the navigation device 80. The acquisition unit 121 calculates the curvature of the road on which the vehicle 10 is currently traveling (hereinafter also referred to as "curve curvature"). If the monitoring system 70 and the navigation device 80 are functioning normally, the acquisition unit 121 acquires the curve curvature based on the information output from the monitoring system 70 and the information output from the navigation device 80. On the other hand, if the monitoring system 70 and the navigation device 80 are not functioning normally, the acquisition unit 121 calculates the curve curvature based on the driving information.

[0020] The route generation unit 122 generates a planned route, which is the route that the vehicle 10 will travel from its current location to its destination. The route generation unit 122 acquires the planned route based on map data provided by the navigation device 80.

[0021] The trajectory generation unit 123 generates the trajectory of the vehicle 10 for automatic driving at predetermined control cycles, based on the planned route and information output from the monitoring system 70. Specifically, the trajectory is one in which the vehicle 10 does not deviate from the lane of the route in the direction of travel of the vehicle 10. Furthermore, the trajectory is one that the vehicle 10 can realistically follow, in accordance with the vehicle's current motion state, such as its speed, and the performance of the drive unit 20, braking unit 30, and steering unit 40. Moreover, the trajectory is one that is not obstructed by other vehicles or obstacles.

[0022] The driver assistance unit 124 performs driving support control, steering support control, and specific control. Driving support control is so-called adaptive cruise control. In driving support control, the driver assistance unit 124 adjusts the driving force and braking force so that the vehicle speed follows a first set speed. The first set speed is set, for example, to a speed desired by the driver. Also, when the vehicle 10 is following a vehicle 10 in front, the first set speed is set to a speed corresponding to the driving speed of the vehicle 10 in front. When the driver assistance unit 124 is performing driving support control, if the driver operates the driving operation member 51 or the driver operates the braking operation member 52, it is preferable for the driver assistance unit 124 to temporarily suspend the driving support control. In other words, in this case, it is preferable that the driving force requested by the driver is applied to the wheels 11 or the braking force requested by the driver is applied to the wheels 11.

[0023] The driver assistance unit 124 adjusts the steering torque in steering assistance control so that the vehicle 10 travels along a set travel trajectory. For example, if the travel trajectory extends in a straight line in the forward direction of the vehicle 10, the steering torque will be "0" or approximately "0". On the other hand, if the travel trajectory curves to the left and right as it moves forward, the steering torque will be larger as the radius of curvature decreases. When the driver operates the steering member 53, a steering torque corresponding to the amount of operation of the steering member 53 is applied to the steering mechanism 41. Therefore, when the driver operates the steering member 53 while the driver assistance unit 124 is performing steering assistance control, the steering torque due to steering assistance control decreases by the amount of steering torque corresponding to the amount of operation of the steering member 53. However, in the following explanation, it is assumed that the driver does not operate the steering member 53 while steering assistance control is being performed.

[0024] As described above, the driver assistance unit 124 performs steering assistance control according to the set driving trajectory. Therefore, if the driving trajectory is not generated due to a malfunction of the monitoring system 70 or the like, the driver assistance unit 124 will not be able to continue steering assistance control. In addition, the driver assistance unit 124 performs steering assistance control by adjusting the steering torque of the steering actuator 42. Therefore, if the steering actuator 42 is unable to output steering torque due to a malfunction of the steering actuator 42 or the like, the driver assistance unit 124 will not be able to continue steering assistance control. Furthermore, if a communication error occurs between the driver assistance unit 124 and the steering control unit 43, or between the steering control unit 43 and the steering actuator 42, the driver assistance unit 124 will not be able to continue steering assistance control.

[0025] When the vehicle 10 is traveling in a straight line, if the driver assistance unit 124 is unable to continue steering assistance control, the steering torque does not change much before and after the steering assistance control is stopped. In this respect, the behavior of the vehicle 10 is unlikely to change. Furthermore, even if the steering torque becomes "0", the vehicle 10 can continue to travel along the road in front of the vehicle. Therefore, the grace period between the stopping of steering assistance control and the driver starting to operate the steering member 53 tends to be long.

[0026] On the other hand, if the driver assistance unit 124 is unable to continue steering assistance control while the vehicle 10 is traveling on a curve, the steering torque will change significantly before and after the steering assistance control is stopped. In this respect, the behavior of the vehicle 10 is likely to change. Also, if the steering torque becomes "0", the vehicle 10 will be unable to continue traveling along the road in front of the vehicle. Therefore, the grace period from when the steering assistance control is stopped until the driver starts operating the steering member 53 tends to be short.

[0027] Therefore, if the driver support unit 124 is unable to continue steering support control while the vehicle 10 is traveling on a curve, it switches from driving support control to specific control. In the specific control, the driver support unit 124 applies braking force to the wheels 11 based on driving information, within the range in which the vehicle 10 can continue to travel. When specific control is executed in this way, the vehicle speed decreases, which increases the time leeway between the end of steering support control and the start of operation of the steering member 53 by the driver. If the driver starts operation of the steering member 53 while the driver support unit 124 is executing the specific control, the driver support unit 124 terminates the specific control. Then, the driver support unit 124 resumes driving support control.

[0028] In specific control, the driver support unit 124 sets a second set speed that is less than the first set speed based on the driving information. Subsequently, the driver support unit 124 applies braking force to the wheels 11 so that the vehicle speed follows the second set speed. The driver support unit 124 may set the second set speed according to the curvature of the curve. For example, the driver support unit 124 preferably sets the second set speed lower the greater the curvature of the curve.

[0029] In specific control, the driver support unit 124 makes the braking force applied to the turning inner wheel greater than the braking force applied to the turning outer wheel. In this way, the driver support unit 124 generates a yaw moment M in the direction in which the vehicle 10 was turning through steering support control. Here, the driver support unit 124 may identify the turning inner wheel and turning outer wheel based on driving information such as lateral acceleration and yaw rate, or it may identify the turning inner wheel and turning outer wheel based on the sign of the curve's curvature. Furthermore, it is preferable for the driver support unit 124 to increase the difference between the braking force applied to the turning inner wheel and the braking force applied to the turning outer wheel as the curve's curvature increases.

[0030] When the driver assistance unit 124 performs specific control, deceleration slip may occur in the wheel 11 to which braking force is applied. For example, the driver assistance unit 124 can determine that deceleration slip has occurred in the wheel 11 if the slip ratio of the wheel 11 exceeds a threshold. If deceleration slip occurs in the wheel 11 while the driver assistance unit 124 is performing specific control, it is preferable to terminate the specific control. In this case, it is preferable that the driver assistance unit 124 does not immediately restart the driving assistance control. In other words, it is preferable that the driver assistance unit 124 maintains a state in which neither driving force nor braking force is applied to the wheel 11 for a while.

[0031] When the driver assistance unit 124 starts executing a specific control, that is, when the steering assistance control is stopped, it is preferable that the driver promptly starts operating the steering member 53. Therefore, when the driver assistance unit 124 starts executing a specific control, it is preferable that it prompts the driver to operate the steering member 53 using voice and warning lights or the like.

[0032] The determination unit 125 determines, based on various information, whether the driver support unit 124 is in a state where it can continue steering support control when the driver support unit 124 is performing steering support control. As described above, the determination unit 125 determines that the driver support unit 124 is no longer able to continue steering support control when a driving trajectory is no longer generated, when the steering actuator 42 malfunctions, or when there is a malfunction in communication with the steering control unit 43. If the determination unit 125 determines that the driver support unit 124 is no longer able to continue steering support control, it outputs a stop command signal to the driver support unit 124 to forcibly stop the steering support control. When the driver support unit 124 receives the stop command signal, if the steering actuator 42 is functioning normally, it is preferable for the driver support unit 124 to perform a degraded process to stop the steering support control that is currently being performed. The degraded process referred to here is a process in which the steering torque applied by the steering actuator 42 to the steering mechanism 41 is gradually reduced.

[0033] <Processing flow executed by the driver assistance unit> Referring to Figure 2, the processing flow executed by the vehicle control device 100 will be explained. This process is executed at predetermined control cycles while steering assistance control is being performed.

[0034] As shown in Figure 2, the driving support unit 124 acquires various information, including driving information (S11). Next, the vehicle control device 100 determines whether the vehicle 10 is traveling on a curve (S12). If the vehicle 10 is not traveling on a curve (S12: NO), the vehicle control device 100 terminates this process. On the other hand, if the vehicle 10 is traveling on a curve (S12: YES), the vehicle control device 100 determines whether steering support control can be continued (S13). If steering support control can be continued (S13: YES), the vehicle control device 100 terminates this process. On the other hand, if steering support control cannot be continued (S13: NO), the vehicle control device 100 temporarily terminates the driving support control and starts specific control (S14). In this way, braking force is applied to the wheels 11, and the vehicle speed is reduced to the second set speed.

[0035] Next, the vehicle control device 100 determines whether or not the vehicle has finished traveling around the curve (S15). For example, the vehicle control device 100 can determine that the vehicle has finished traveling around the curve if the curvature of the road that the vehicle 10 will travel on, which is obtained based on the monitoring results of the monitoring system 70, is less than a predetermined curvature determination value. If the vehicle 10 has finished traveling around the curve (S15: YES), the vehicle control device 100 terminates the specific control and resumes the driving support control (S16). In other words, the braking force applied to the wheels 11 is released, and the vehicle speed increases to the first set speed. After that, the vehicle control device 100 terminates this process.

[0036] On the other hand, if the vehicle 10 is traveling on a curve (S15: NO), the vehicle control device 100 determines whether the driver has started operating the steering member 53 (S17). If the driver has started operating the steering member 53 (S17: YES), the vehicle control device 100 proceeds to step S16. On the other hand, if the driver has not started operating the steering member 53 (S17: NO), the vehicle control device 100 determines whether deceleration slip is occurring in the wheel 11 to which braking force is applied (S18). If deceleration slip is occurring in the wheel 11 (S18: YES), the vehicle control device 100 proceeds to step S16. In this case, it is preferable that the vehicle control device 100 does not immediately restart the driving support control even after terminating the specific control. If deceleration slip is not occurring in the wheel 11 (S18: NO), the vehicle control device 100 determines whether the elapsed time since the start of the specific control has exceeded a predetermined time (S19). Furthermore, the vehicle control device 100 determines whether the vehicle speed is appropriate (S19). Here, an appropriate vehicle speed is defined as the vehicle speed being less than or equal to the second set speed. If the elapsed time since the start of specific control is longer than a predetermined time and the vehicle speed is appropriate (S19: YES), the vehicle control device 100 proceeds to step S16. On the other hand, if the above conditions are not met (S19: NO), the vehicle control device 100 reacquires various information (S20). After that, the vehicle control device 100 proceeds to step S15.

[0037] Furthermore, even if the vehicle control device 100 is unable to continue steering assistance control (S13: NO), it may terminate the specific control if it is possible to resume steering assistance control (S16). In this case, it is preferable for the vehicle control device 100 to resume both steering assistance control and driving assistance control.

[0038] <Operation and Effects of this Embodiment> When the vehicle control device 100 performs steering support control and driving support control, the driver can make the vehicle 10 travel along the planned route without having to operate the drive operation member 51, the brake operation member 52, and the steering member 53.

[0039] As shown in Figure 3, if the steering assist control is forcibly terminated while the vehicle 10 is traveling on a curve, the vehicle 10 may deviate from its intended path as indicated by the dashed arrow. In other words, the vehicle 10 may become unable to travel along the curved lane. In contrast, the vehicle control device 100 of this embodiment, when the steering assist control is forcibly terminated while the vehicle 10 is traveling on a curve, executes a specific control instead of the driving assist control. That is, braking force is applied to the wheels 11, causing the vehicle 10 to decelerate. As a result, the driver is able to start operating the steering member 53 between the time the steering assist control is forcibly terminated and the vehicle 10 deviates from the curved lane. Thus, as shown by the solid line, the vehicle control device 100 can make the vehicle 10 travel along the curve by the driver's operation of the steering member 53. Therefore, even if the steering assist control is stopped while the vehicle 10 is traveling on a curve, the vehicle control device 100 is able to make it easier for the vehicle 10 to continue traveling along the curve. Based on the above, the vehicle control device 100 can appropriately assist the vehicle 10 during the period when the vehicle 10 is traveling on a curve and transitioning from steering assistance control to manual steering by the driver.

[0040] This embodiment can further achieve the following effects: (1) In specific control, the vehicle control device 100 applies braking force to the wheels 11 so that the vehicle speed follows the second set speed. As a result, the vehicle control device 100 can enhance safety when the vehicle 10 is traveling around a curve, by ensuring that the vehicle speed is below the first set speed in the driving support control. In addition, the vehicle control device 100 can give the driver a sense of security when the steering support control is forcibly terminated.

[0041] (2) In a specific control, the vehicle control device 100 makes the braking force applied to the turning inner wheel greater than the braking force applied to the turning outer wheel. In this way, the vehicle control device 100 generates a yaw moment M in the vehicle 10, as shown in Figure 3. Therefore, the vehicle control device 100 can turn the vehicle 10 even when no steering torque is applied to the steering mechanism 41.

[0042] (3) A vehicle control device 100 executes specific control based on the curvature of a curve. For example, in the specific control, the vehicle control device 100 can increase the braking force applied to wheels 11 as the curvature of the curve increases, or increase the difference between the braking force applied to the inner turning wheel and the braking force applied to the outer turning wheel. Therefore, the vehicle control device 100 can execute the specific control suitable for the curve during traveling.

[0043] (4) When a monitoring system 70 and a navigation device 80 do not function normally, the vehicle control device 100 acquires the curvature of a curve based on traveling information which is a state quantity indicating a motion state of a vehicle 10. Therefore, even when steering assist control cannot be continued due to a malfunction of the monitoring system 70 and the navigation device 80, the vehicle control device 100 can execute the specific control based on the curvature of the curve.

[0044] (5) The vehicle control device 100 terminates the specific control if deceleration slip occurs on a wheel 11 during execution of the specific control. Therefore, the vehicle control device 100 can suppress occurrence of deceleration slip due to execution of the specific control. Furthermore, when terminating the specific control due to occurrence of deceleration slip, the vehicle control device 100 does not resume driving support control immediately. Therefore, when terminating the specific control due to occurrence of deceleration slip, the vehicle control device 100 can suppress an increase in vehicle body speed caused by resuming the driving support control.

[0045] <Modification> The present embodiment can be implemented with the following modifications. The present embodiment and the following modifications can be combined with each other within a technically consistent range.

[0046] ・In the specific control, the braking force applied to the outer turning wheel may be equal to the braking force applied to the inner turning wheel. ・In the specific control, a yaw moment M generated in the vehicle 10 by providing a difference between the braking force applied to the outer turning wheel and the braking force applied to the inner turning wheel may be a moment that moves the vehicle 10 away from an oncoming lane.

[0047] • In the specific control, the magnitude of the braking force applied to the wheels 11 may be constant regardless of the curvature of the curve. • The vehicle control device 100 does not have to terminate the specific control if deceleration slip occurs on the wheels 11 during execution of the specific control. In this case, the driving support unit 124 may allow intervention of ABS control to reduce deceleration slip of the wheels 11 in the specific control.

[0048] • In the specific control, the vehicle control device 100 may cause braking force to be applied only to the front wheels FL, FR among the front wheels FL, FR and the rear wheels RL, RR, or may cause braking force to be applied only to the rear wheels RL, RR.

[0049] • The vehicle control device 100 does not have to calculate the curvature of a curve based on travel information. That is, the curvature of a curve may be acquired based on information output from the monitoring system 70 and information output from the navigation device 80.

[0050] • The specific control may be control that maintains the yaw rate and lateral acceleration of the vehicle 10 constant by adjusting the braking force applied to the wheels 11. • The travel information may be information output from the monitoring system 70 and information output from the navigation device 80. That is, the travel information does not have to be a state quantity indicating the motion state of the vehicle 10.

[0051] • The braking mechanism 31 and the braking actuator 32 may be configured to be capable of applying braking force to the wheels 11 without intervention of brake fluid. For example, the braking actuator 32 may be a linear actuator that drives a piston of the braking mechanism 31. In this case, the linear actuator can apply braking force to the wheels 11 by pressing a friction material 312 against a rotating body 311 via the piston of the braking mechanism 31.

[0052] The vehicle control device 100 is not limited to a processing circuit 110 that includes a CPU 111 and a memory 112 and executes software processing. For example, the vehicle control device 100 may include a dedicated hardware circuit that executes at least a part of the various processes performed in the above embodiment. An example of a dedicated hardware circuit is an ASIC. ASIC is an abbreviation for "Application Specific Integrated Circuit". In other words, the vehicle control device 100 may have any of the following configurations (a) to (c).

[0053] (a) A processing circuit comprising a processing unit that executes all of the above processes according to a program, and a program storage device such as a ROM that stores the program. (b) A processing circuit comprising a processing unit and a program storage device that execute a part of the above processes according to a program, and a dedicated hardware circuit that executes the remaining processes.

[0054] (c) A processing circuit equipped with dedicated hardware circuits to perform all of the above processing. Here, there may be multiple software execution devices equipped with processing units and program storage devices, and multiple dedicated hardware circuits.

Claims

1. A vehicle control device applicable to a vehicle comprising a steering actuator for applying steering torque to a steering mechanism, a driving actuator for applying driving force to wheels, and a braking actuator for applying braking force to the wheels, the vehicle control device comprising a driving support unit that performs steering support control to adjust the steering torque so that the vehicle travels along a set driving trajectory, and driving support control to adjust the driving force and the braking force so that the vehicle speed follows a set first set speed, wherein the driving support unit, when the vehicle is traveling on a curve and the steering support control cannot be continued, instead performs specific control to apply the braking force to the wheels based on driving information indicating the driving state of the vehicle, within a range in which the vehicle can continue to travel.

2. The vehicle control device according to claim 1, wherein the driving support unit, in the specific control, sets a second set speed less than the first set speed based on the driving information, and applies the braking force to the wheels so that the vehicle speed follows the second set speed.

3. When the vehicle is traveling on a curve, the inner wheel of the left and right wheels of the vehicle is the inner turning wheel, and the outer wheel is the outer turning wheel, and the driving support unit, in the specific control, makes the braking force applied to the inner turning wheel greater than the braking force applied to the outer turning wheel.

4. The vehicle control device according to claim 2 or 3, wherein the driving support unit, in the specific control, applies the braking force to the wheels according to the curvature of the curve calculated based on the driving information, and the driving information is a state quantity indicating the motion state of the vehicle.

5. The vehicle control device according to any one of claims 1 to 3, wherein the driving support unit terminates the specific control if deceleration slip occurs in the wheels during the execution of the specific control.

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