Vehicle control device and vehicle control program

Abstract

To improve safety by shortening an idle travel distance of a vehicle.SOLUTION: A vehicle 10 comprises a motor 23 for travel and a brake device 27 as a braking force generation device capable of generating braking force not by driver's brake operation, and also comprises a drive assist ECU 20 which assists in driving the vehicle 10. The drive assist ECU 20 determines that the driver has performed abrupt steering, and then controls the motor 23 for travel into a regenerative state and also commands a brake device 27 to operate based upon the determination result so as to generate braking force using the motor 23 for travel and the brake device 27.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] When there is a sudden emergence of an obstacle such as a small animal in a moving vehicle, it is desirable that the vehicle takes appropriate measures in response to the emergence of the obstacle. For example, in Patent Document 1, it is determined whether a collision with an obstacle can be avoided based on the detection result of the obstacle by an obstacle sensor and the situation of the braking operation by the driver. When it is determined that the collision cannot be avoided by the driver's braking operation, a technique is proposed in which the braking device is controlled on the vehicle side according to the vehicle deceleration required for assisting the avoidance of the obstacle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when the vehicle is running, the steering may be suddenly operated (sudden steering) by the driver in response to the above-mentioned sudden emergence or the like. In this case, it is considered that the braking operation by the driver may be delayed with respect to the steering operation. At that time, it is assumed that the coasting distance, which is the distance until the brake actually starts to take effect, becomes long. It is feared that the increase in the coasting distance will make it difficult to avoid obstacles and the like. Thus, there is still room for technical improvement in shortening the coasting distance of the vehicle and improving safety.

[0005] The present invention has been made in view of the above problems, and its main object is to provide a vehicle control device and a vehicle control program capable of shortening the coasting distance of a vehicle and improving safety.

Means for Solving the Problem

[0006] The means for solving the above problem will be described below.

[0007] The present invention is applied to a vehicle equipped with a braking force generating device capable of generating braking force without depending on the driver's braking operation, and includes a sharp steering determination unit that determines that sharp steering has been performed in the vehicle, and a brake control unit that generates braking force by controlling the braking force generating device based on the determination result that sharp steering has been performed.

[0008] According to the present invention, when the driver performs sharp steering, the braking force generating device is controlled to generate braking force triggered by the sharp steering. By adopting such a configuration that generates braking force promptly without waiting for the driver's braking operation, for example, the coasting distance of the vehicle can be shortened compared to a configuration where braking force is generated triggered by a braking operation after sharp steering. That is, it is possible to suppress the delay in the driver's braking operation from directly leading to a delay in braking. Thereby, it can contribute to the improvement of the safety of the vehicle.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

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Figure 10

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Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments in which the vehicle control device of the present invention is embodied will be described with reference to the drawings. This embodiment is embodied as a driving support system for an electric vehicle. First, the schematic configuration of the driving support system will be described with reference to FIG. 1.

[0011] The vehicle 10 is an EV vehicle that runs by supplying the electric power stored in the battery 21 to the traveling motor 23 (rotating electric machine) via the inverter 22. The inverter 22 is connected to the motor ECU 24, and the traveling motor 23 is switched between the power running state and the regeneration state by the inverter control of the motor ECU 24. The motor ECU 24 controls the electric power supplied from the battery 21 to the traveling motor 23 in the power running state, and controls the electric power supplied from the traveling motor 23 to the battery 21 in the regeneration state.

[0012] In addition, the vehicle 10 is provided with a hydraulic braking device 27 that generates a braking force on each wheel 11 of the vehicle 10. The braking device 27 is a friction braking device having a braking member 28 such as a brake pad and a caliper provided on each wheel 11, and a drive module 29 that drives the braking member 28. The drive module 29 has a well-known hydraulic mechanism. The braking device 27 generates a braking force due to friction on each wheel 11 when a brake pedal (not shown) is depressed by the driver.

[0013] The driving support ECU 20 is connected to the motor ECU 24 and the brake device 27, enabling the implementation of motor control and brake control as driving support control by the driving support ECU 20. The driving support ECU 20 is connected to an object detection device 31 that detects objects existing around the vehicle 10, a brake sensor 32 that detects the operation amount of the brake pedal, a steering sensor 33 that detects the steering operation amount (steering angle), a wheel speed sensor 34 that detects the rotational speed of each wheel 11, a yaw rate sensor 35 that detects the yaw rate of the vehicle 10, and a driver camera 36 that monitors the state of the driver in the vehicle interior. Note that the object detection device 31 is a camera that images the surroundings of the vehicle, a distance measuring sensor that measures the distance to an object, etc. The driver camera 36 is an in-vehicle camera for acquiring information such as the driver's posture, line of sight, blinking, and face direction.

[0014] Based on the detection results of the above-mentioned various sensors and the like, the driving support ECU 20 calculates command values related to the drive of the driving motor 23 and command values related to the drive of the brake device 27, and appropriately outputs these command values to the motor ECU 24 and the brake device 27. Thereby, control of the driving motor 23 and control of the brake device 27 by the driving support ECU 20 are made possible. In particular, in this embodiment, as brake control by the driving support ECU 20, a regenerative brake that generates braking force (regenerative braking force) by setting the driving motor 23 to a regenerative state and a friction brake that generates braking force (frictional braking force) by driving the brake device 27 can be implemented. Note that the driving motor 23 and the brake device 27 correspond to the "braking force generating device", and the driving support ECU 20 corresponds to the "vehicle control device".

[0015] Further, when the driver is in a state of loss of consciousness due to drowsiness, illness, or the like, the driving support ECU 20 determines that the driver is in a state of loss of consciousness based on the analysis result of the image of the driver camera 36.

[0016] The motor ECU 24 has a function of calculating the SOC (remaining capacity) of the battery 21, and the SOC calculated by the motor ECU 24 is output to the driving support ECU 20. As is well known, the SOC is sequentially updated by adding and subtracting the charging current and the discharging current flowing through the battery 21 and calculating the current integrated value. Further, the motor ECU 24 controls the charging and discharging of the battery 21 so that the SOC of the battery 21 is maintained within a range defined between a predetermined SOC lower limit value and a predetermined SOC upper limit value. For example, the SOC lower limit value is 20% and the SOC upper limit value is 80%.

[0017] Here, when an obstacle such as a small animal suddenly jumps out in front of the traveling vehicle 10, the steering may be suddenly operated by the driver prior to the brake pedal in response to the jump-out. Further, such a sudden operation of the steering may also occur when the driver loses consciousness during vehicle operation and the body tilts. When the sudden operation of the steering precedes the sudden operation of the brake pedal, the coasting distance until the braking force is generated becomes longer. That is, the timing at which the braking force is generated is delayed due to the delay in the operation of the brake pedal. The driving support system in the present embodiment is configured to start the automatic brake control when the driver suddenly operates the steering, thereby shortening the above-mentioned coasting distance.

[0018] Hereinafter, with reference to the flowchart of FIG. 2, the configuration for realizing the automatic brake control, specifically, the automatic brake process executed as a periodic process of a predetermined period in the driving support ECU 20 will be described.

[0019] In the automatic braking process, first, at step S101, it is determined whether the braking flag is set. The braking flag is a flag that is set when automatic braking control starts along with a sudden operation (sudden steering) of the steering wheel, and is erased when the automatic braking control ends. If the braking flag is not set, the process proceeds to step S102 to determine whether a sudden steering has occurred. Specifically, the driving support ECU 20 calculates the jerk of the steering angle from the detection information of the steering sensor 33, and determines that a sudden steering has occurred when the jerk of the steering angle exceeds a predetermined threshold value. The jerk of the steering angle may be calculated as the rate of change of acceleration per unit time.

[0020] If it is determined that no sudden steering has occurred, the automatic braking process ends as it is. On the other hand, if it is determined that a sudden steering has occurred, the process proceeds to step S103. In step S103, it is determined based on the detection information of the brake sensor 32 whether the brake pedal is being operated (manually operated) by the driver. If it is determined that the brake pedal is being operated, the automatic braking process ends as it is. If it is determined that the brake pedal is not being operated, the automatic brake start process of steps S104 to S110 is executed.

[0021] In the automatic brake start process, first, the state of the road surface on which the vehicle 10 is traveling and the turning state of the vehicle 10 are grasped (step S104). For example, the road surface μ may be calculated based on the rotational speed of each wheel 11 detected by the wheel speed sensor 34 and the vehicle speed, and the road surface μ may be grasped as the road surface state. Also, the turning state of the vehicle 10 may be calculated based on the yaw rate detected by the yaw rate sensor 35 and the vehicle speed.

[0022] After that, in step S105, the required braking force PX for automatic brake control is set. This required braking force PX is the total braking amount generated on the vehicle 10, and at the beginning of the start of automatic brake control, it is the braking force that is the sum of the regenerative braking force realized by the regeneration of the driving motor 23 and the frictional braking force realized by the drive of the braking device 27. At this time, the required braking force PX may be set based on the road surface condition and turning state grasped in step S104 and the vehicle speed of the vehicle 10. For example, when μ of the road surface is low on a rainy day or the like, or when turning (when the turning radius is large), the required braking force PX is suppressed low to suppress the locking of the tires by automatic brake control. That is, the required braking force PX is set to be the maximum braking force within the range where the locking of the tires by automatic brake control can be avoided.

[0023] In the subsequent step S106, the required braking force PX is distributed to the regenerative braking force realized by the regeneration of the driving motor 23 and the frictional braking force realized by the drive of the braking device 27. At this time, using the torque characteristics of the driving motor 23 that define the relationship between the motor rotation speed (vehicle speed) and torque, the regenerative braking force is set based on the motor rotation speed each time. This regenerative braking force is the upper limit value of the regenerative braking force of the driving motor 23 determined based on the torque characteristics. The regenerative braking force (upper limit value of the regenerative braking force) may be set based on the road surface condition and turning state. For example, the regenerative braking force may be made smaller as the road surface condition has a lower μ, and the regenerative braking force may be made smaller as the turning radius is smaller. A configuration in which the regenerative braking force is set based on either one of the road surface condition and turning state may also be used. Also, the frictional braking force is calculated by subtracting the regenerative braking force from the required braking force PX to compensate for the shortage of the regenerative braking force with respect to the required braking force PX, at least at the beginning of the start of automatic brake control.

[0024] In the subsequent step S107, a process of raising the upper limit value of the SOC of the battery 21 is performed. Specifically, the upper limit value of the SOC of the battery 21 is raised from the upper limit value L1, which is the normal-time upper limit value of the SOC, to the upper limit value L2, which is the emergency-time upper limit value of the SOC, and charging exceeding the upper limit value L1 is permitted. Thereby, even when the automatic brake control is executed in a situation where the actual SOC of the battery 21 is close to the upper limit value L1, it is possible to suppress the regenerative braking force from not being exerted due to the regeneration failure. Note that the upper limit value L2 can be any value as long as it is larger than the upper limit value L1.

[0025] Thereafter, in steps S108 and S109, the automatic brake control is started. Specifically, in step S108, a regeneration command for setting the traveling motor 23 in a regenerative state is output (regenerative brake ON), and in step S109, an operation command for operating the brake device 27 is output (friction brake ON). Thereby, the regenerative operation of the traveling motor 23 is started and the hydraulic operation of the brake device 27 is started. In this way, although the regeneration command of the traveling motor 23 and the operation command of the brake device 27 are output simultaneously, there is a difference in the time until the braking force is actually generated between the regenerative braking force and the frictional braking force. Specifically, the frictional braking force is generated with a delay compared to the regenerative braking force.

[0026] Thereafter, in step S110, the braking flag is set and this process is once terminated.

[0027] After the automatic brake control is started due to sudden steering, that is, when an affirmative determination is made in step S101 by setting the braking flag, the process proceeds to step S111. In step S111, it is determined based on the detection information from the brake sensor 32 whether or not the brake pedal has been operated (manually operated) by the driver. If the manual operation has not been performed, a negative determination is made in step S111 and the process proceeds to step S112. In step S112, it is determined whether or not the vehicle speed has become 0 and the vehicle has stopped. If the vehicle has not stopped, after executing the state transition process in step S113, this process is once terminated. Hereinafter, the state transition process will be described with reference to FIG. 3.

[0028] The state transition process is a process of transitioning from a state (the first state) where a required braking force PX is generated by a regenerative braking force and a frictional braking force after the frictional braking force by the braking device 27 starts to take effect after the start of the automatic braking control, to a state (the second state) where the required braking force PX is generated by the frictional braking force. In this state transition process, first, in step S201, it is determined whether it is before the state transition. If an affirmative determination is made in step S201, the actual SOC of the battery 21 is acquired in step S202.

[0029] In the subsequent step S203, it is determined whether the actual SOC is less than the upper limit value L1. If the actual SOC is less than the upper limit value L1, the process proceeds to step S204, and at the current time, it is determined whether the braking device 27 is in a state where it can generate a frictional braking force corresponding to the required braking force PX. Specifically, for example, on the condition that the elapsed time from the operation command to the braking device 27 has reached a predetermined time, it is determined that the braking device 27 is in a state where it can generate a frictional braking force corresponding to PX. This predetermined time may be, for example, a fixed time determined in advance, or a time variably set according to the required braking force PX. For example, the larger the required braking force PX, the longer the predetermined time may be set. Alternatively, in step S204, the brake hydraulic pressure in the braking device 27 may be detected, and based on the detection information, it may be determined whether the braking device 27 is in a state where it can generate a frictional braking force corresponding to PX.

[0030] If the braking device 27 is in a state where it can generate a frictional braking force equivalent to PX, it is considered that a state transition is possible, and the process proceeds to step S205. In step S205, a transition is executed from a state where the required braking force PX is generated by the regenerative braking force and the frictional braking force to a state where the required braking force PX is generated by the frictional braking force. At this time, the regeneration command of the driving motor 23 is turned off, and the frictional braking force of the braking device 27 is increased to the required braking force PX. Note that when increasing the frictional braking force to the required braking force PX, it is also possible to gradually decrease the regenerative braking force so that the required braking force PX does not temporarily decrease.

[0031] On the other hand, if the actual SOC exceeds the upper limit value L1 in step S203, the process proceeds to step S206. In step S206, an SOC flag indicating that the actual SOC has exceeded the upper limit value L1 is set.

[0032] In the subsequent step S207, it is determined whether or not the frictional braking force of the braking device 27 is being generated. This determination may be made, for example, based on the elapsed time from the operation command to the braking device 27. If the frictional braking force is being generated, the process proceeds to step S205, and a transition is executed from a state where the required braking force PX is generated by the regenerative braking force and the frictional braking force to a state where the required braking force PX is generated by the frictional braking force. Also, if the frictional braking force is not being generated, the process proceeds to the subsequent step S208.

[0033] In step S208, it is determined whether or not the actual SOC exceeds the upper limit value L2. If the actual SOC exceeds the upper limit value L2, the process proceeds to step S205, and a transition is executed from a state where the required braking force PX is generated by the regenerative braking force and the frictional braking force to a state where the required braking force PX is generated by the frictional braking force. Also, if the actual SOC does not exceed the upper limit value L2, this process is once terminated as it is.

[0034] Returning to the description of the automatic braking process in FIG. 2, if an affirmative determination is made in either step S111 or S112, the process proceeds to step S114. In step S114, the automatic brake control is released, and the brake control is shifted to normal brake control corresponding to the driver's manual brake. In the subsequent step S115, the upper limit value of the SOC of the battery 21 is returned to the normal upper limit value L1. Also, in step S116, the braking flag is erased, and this process ends. Note that after the vehicle has stopped, a process for maintaining the stopped state of the vehicle (for example, turning on the electric parking brake) may be executed.

[0035] According to the automatic braking process in FIG. 2 above, during the regeneration of the driving motor 23, the actual SOC of the battery 21 may exceed the upper limit value L1. In this case, the driving support ECU 20 may limit the regeneration operation of the driving motor 23 while the actual SOC exceeds the upper limit value L1. Specifically, the driving support ECU 20 executes the charge limit process shown in FIG. 4 at a predetermined cycle.

[0036] In FIG. 4, in step S301, it is determined whether the SOC flag is set. This SOC flag is a flag set according to the determination result in step S203 of FIG. 3. If the SOC flag is set, the process proceeds to step S302, and it is determined whether the actual SOC exceeds the upper limit value L1 at the current time.

[0037] Then, if it is determined in step S302 that the actual SOC exceeds the upper limit value L1, the process proceeds to step S303, and a charge limit state for limiting the charging of the battery 21 is set. Specifically, even when the vehicle is in a decelerating state during vehicle travel, the regenerative charging of the driving motor 23 is prohibited or the regenerative power is reduced to a predetermined value or less. Also, if it is determined that the actual SOC does not exceed the upper limit value L1, the process proceeds to step S304, and the SOC flag is erased. Note that when the SOC flag is set, it is also possible to consume battery power by actively using in-vehicle electrical loads (use exceeding the original driving requirements).

[0038] Hereinafter, with reference to the timing charts of FIGS. 5 and 6, the flow of the above-described automatic braking process will be described. The automatic braking process differs depending on whether the actual SOC of the battery 21 exceeds the upper limit value L1 or not. First, using FIG. 5, the flow of automatic braking when the actual SOC of the battery 21 does not exceed the upper limit value L1 will be described. In FIGS. 5 and 6, an example is shown in which when there is a sudden jump-out for the traveling vehicle 10, the steering is suddenly operated by the driver while the brake pedal is not operated.

[0039] At the timing of ta1, it is determined by the driving support ECU 20 that sudden steering has been performed. Based on this determination result, a braking flag is set, and automatic braking control by the driving support system is started. In the automatic braking control, the SOC upper limit value of the battery 21 is raised from the upper limit value L1 to the upper limit value L2, and charging exceeding the upper limit value L1 is permitted. Then, a regeneration command for the traveling motor 23 is output, and an operation command for the brake device 27 is output.

[0040] At the timing of ta1, the traveling motor 23 is switched to the regeneration state. The regenerative brake by the traveling motor 23 is superior in responsiveness compared to the friction brake, and regenerative braking force is quickly generated when it becomes the regeneration state. As a result, the deceleration of the vehicle 10 is quickly started after sudden steering. Thereafter, while the regenerative brake is operating, the battery 21 is charged by the regenerative power of the traveling motor 23, and the actual SOC of the battery 21 gradually increases.

[0041] Since the frictional braking force generated by the brake device 27 is delayed in the onset of the braking force compared to the regenerative braking force, the frictional braking force is applied at the timing of ta2 later than the timing of ta1. That is, after the timing of ta2, both the regenerative braking force and the frictional braking force are generated. Note that the regenerative braking force is maintained at the upper limit value after reaching the regenerative braking force upper limit value. Then, due to the regenerative braking force and the frictional braking force, a braking force corresponding to the required braking force PX is generated in the vehicle 10.

[0042] Thereafter, at the timing of ta3, it is considered that the braking device 27 has become capable of generating a frictional braking force equivalent to PX, and a transition is made from a state where the required braking force PX is generated by the regenerative braking force and the frictional braking force to a state where the required braking force PX is generated by the frictional braking force. At this time, the regeneration of the driving motor 23 is stopped, and the increase in the actual SOC stops. In the example shown in FIG. 5, although the actual SOC has been increasing during the operation of the regenerative brake, the actual SOC has always been below the upper limit value L1. After ta3, a state is entered in which a frictional braking force equivalent to PX is generated by the braking device 27.

[0043] Thereafter, for example, at the timing of ta4 when the vehicle speed becomes 0, the braking flag is erased and the automatic brake control is released. At that time, the operation command from the driving support ECU 20 to the braking device 27 is stopped, and the control returns to the normal brake control. Also, the SOC upper limit value of the battery 21 is returned from the upper limit value L2 to the upper limit value L1.

[0044] Next, with reference to the timing chart of FIG. 6, the flow of the automatic brake when the actual SOC of the battery 21 exceeds the upper limit value L1 will be described.

[0045] At the timing of tb1, based on the determination result that a sudden steering operation has been performed, the braking flag is set, the upper limit of the SOC is raised, the regeneration command for the driving motor 23 and the operation command for the braking device 27 are output. This is the same as the timing of ta1 in FIG. 5. However, compared with the example shown in FIG. 5, the difference between the actual SOC at the start of the automatic brake control and the upper limit value L1 is smaller. Therefore, at the timing of tb2, the actual SOC exceeds the upper limit value L1 due to the regeneration of the driving motor 23.

[0046] After that, at the timing of tb3, it is determined that the actual SOC of the actual SOC exceeds the upper limit value L1 and the frictional braking force of the braking device 27 is generated. Therefore, the transition is made from the state of generating the required braking force PX by the regenerative braking force and the frictional braking force to the state of generating the required braking force PX by the frictional braking force. After tb3, a state is entered in which a frictional braking force equivalent to PX is generated by the braking device 27.

[0047] After that, for example, at the timing of tb4 when the vehicle speed becomes 0, the braking flag is erased, and the automatic brake control is released to return to the normal brake control.

[0048] In the example shown in FIG. 6, in the automatic brake control, the actual SOC of the battery 21 exceeds the upper limit value L1 and is in a state of exceeding the SOC at the end of the automatic brake control. In such a case, during vehicle running after the automatic brake control is released, the charging of the battery 21 is restricted.

[0049] That is, after the release of the automatic brake control, the running of the vehicle 10 is restarted at the timing of tb5. During the running of the vehicle, the battery power is consumed with the power running drive of the running motor 23, and the actual SOC of the battery 21 gradually decreases. After that, at the timing of tb6, when the accelerator is turned off, the vehicle 10 decelerates. However, since the actual SOC exceeds the upper limit value L1, the regenerative power generation of the running motor 23 is restricted, and the increase in the actual SOC is suppressed. When the driver performs a braking operation during vehicle deceleration, a braking force is generated by the friction brake as shown in the figure.

[0050] As described in detail above, in this embodiment, automatic braking control is started when a sudden steering operation is performed. Therefore, for example, compared with a conventional vehicle (see Fig. 7(a)) that does not have a function of executing this automatic braking control, the coasting distance when the brake pedal is operated with a delay from the sudden steering operation can be shortened (see Fig. 7(b)). Thereby, the distance (stopping distance) from the sudden steering occurrence position to the position where the vehicle 10 stops can be shortened. That is, it is possible to suppress the delay in the driver's brake operation from directly leading to a delay in braking. Thereby, it is possible to contribute to an improvement in vehicle safety.

[0051] Regarding the brake device 27, it is necessary to increase the brake hydraulic pressure to generate braking force, and there is a slight delay until the braking force is generated. On the other hand, for the regenerative brake of the driving motor 23, the time until the braking force is generated is shorter than that of the brake device 27. In the automatic braking control of this embodiment, by turning on the regenerative brake and the friction brake simultaneously, it is possible to shorten the time from the occurrence of sudden steering to the generation of braking force. Also, while the regenerative brake is excellent in responsiveness, the friction brake is excellent in terms of sustainability and the like. Therefore, in an emergency, by turning on both brakes, first, the coasting distance is shortened by the regenerative brake, and the subsequent braking force is supplemented by the friction brake that operates with a delay, so that the anxiety regarding the sustainability of the regenerative brake can be preferably eliminated.

[0052] By waiting for the operation of the friction brake and stopping the regenerative brake or the like, it is possible to suppress an excessive drop in the braking force during the automatic braking control. Also, stopping the regenerative brake is preferable for suppressing excessive charging.

[0053] In the automatic braking control shown in this embodiment, the regenerative braking force is set according to the grasped road surface conditions and the like. Since the regenerative brake has high responsiveness, the braking force can increase suddenly at the start of the automatic braking control. When a sudden steering operation is performed under slippery conditions such as driving on a low-μ road or during turning, it is possible to suppress a rapid increase in the braking force when generating the braking force by automatic braking, and it is possible to suitably suppress the disturbance of the behavior of the vehicle 10 during automatic braking.

[0054] <Other Embodiments> · Instead of the state transition process of FIG. 3, it may be configured to execute the state transition process of FIG. 8. FIG. 8 is a modification of a part of FIG. 3. For the same processes as those in FIG. 3, the same step numbers are assigned and the description thereof is omitted.

[0055] In FIG. 8, when the actual SOC is less than the upper limit value L1 and the brake device 27 is in a state where it can generate a frictional braking force corresponding to the required braking force PX (when both steps S203 and S204 are YES), in step S401, it is determined whether the vehicle speed is less than a predetermined threshold Th. The threshold Th is, for example, 10 km / h. If the vehicle speed is equal to or higher than the predetermined threshold Th, this process is temporarily terminated. If the vehicle speed is less than the predetermined threshold Th, the process proceeds to step S205, and a transition is executed from a state where the required braking force PX is generated by the regenerative braking force and the frictional braking force to a state where the required braking force PX is generated by the frictional braking force.

[0056] Explaining with the timing chart of FIG. 5, at the timing of ta3, when the brake device 27 becomes in a state where it can generate a frictional braking force corresponding to PX, if the actual SOC is less than the upper limit value L1 and the vehicle speed is equal to or higher than the threshold Th, there is a margin up to the SOC upper limit in the actual SOC and the vehicle speed is still high, so the state where the required braking force PX is generated by the regenerative braking force and the frictional braking force is maintained. Then, when the vehicle speed drops to the threshold Th, a transition is made from a state where the required braking force PX is generated by the regenerative braking force and the frictional braking force to a state where the required braking force PX is generated by the frictional braking force.

[0057] ·At the beginning of the automatic braking control, the regenerative braking force by the driving motor 23 may be temporarily increased above the upper limit value. Specifically, as shown in FIG. 9, when generating a braking force corresponding to the required braking force PX by outputting a regenerative brake command and a friction brake command, before the friction braking force starts to take effect, the regenerative braking force is set to a braking force exceeding the upper limit value. At this time, the upper limit value of the regenerative braking force may be set using, for example, the torque characteristics of the driving motor 23 that define the relationship between the motor rotation speed (vehicle speed) and torque. The period for generating a regenerative braking force exceeding the upper limit value may be a predetermined time determined in advance.

[0058] According to this configuration, after the start of the automatic braking control, a braking force corresponding to the required braking force PX can be quickly generated. Also, by limiting the period during which the regenerative braking force exceeds the upper limit value to a short time, an excessive increase in the SOC can be suppressed.

[0059] ·When implementing the automatic braking control, the magnitude of the required braking force PX may be changed between an initial period including the beginning and a subsequent period. Specifically, as shown in FIG. 10, in the first period T1 at the beginning of the automatic braking control, the required braking force PX of the automatic braking control is set to a strong braking force (e.g., 0.5G) greater than the normal braking force (e.g., 0.3G), and in the subsequent second period T2, the required braking force PX of the automatic braking control is reduced to the normal braking force. In this case, for example, based on the vehicle speed becoming less than a predetermined value, a transition may be made from the first period T1 to the second period T2.

[0060] ·In the above embodiment, when it is determined that a sudden steering operation has been performed, the SOC upper limit value is increased from the normal upper limit value L1 to the upper limit value L2. However, when the cause of the sudden steering operation is the driver's loss of consciousness, charging of the battery 21 exceeding the upper limit value L2 may be permitted.

[0061] Specifically, in step S107 of FIG. 2, it is advisable to perform the process of raising the upper limit of the SOC shown in FIG. 11. In step S501 of FIG. 11, it is determined whether the driver is in a state of unconsciousness. At this time, the image of the driver captured by the driver camera 36 is analyzed, and it is determined from the analysis result whether the driver is in a state of unconsciousness. If the driver is not in a state of unconsciousness, the process proceeds to step S502, and "L21" is set as the upper limit value L2 obtained by raising the SOC upper limit value. If the driver is in a state of unconsciousness, the process proceeds to step S503, and "L22" is set as the upper limit value L2 obtained by raising the SOC upper limit value. Here, the upper limit value L22 when the driver is in a state of unconsciousness is a value larger than the upper limit value L21 when the driver is not in a state of unconsciousness (L22 > L21).

[0062] When a sudden steering operation is performed under unconsciousness, an operation by the driver (such as a steering operation or a braking operation) cannot be expected, and it can be said that the situation is one with a higher degree of urgency. In this regard, with the above configuration, appropriate automatic braking control can be implemented in a situation where a sudden steering operation is performed under unconsciousness.

[0063] · The automatic braking control may be terminated or the braking force of the automatic braking control may be reduced on the condition that, after the start of the automatic braking control associated with a sudden steering operation, a return operation is performed by the driver to return the steering in the direction opposite to the sudden steering operation. Specifically, the driving support ECU 20 may execute the automatic braking process shown in FIG. 12. FIG. 12 is a modified part of FIG. 2. For the same processes as those in FIG. 2, the same step numbers are assigned and the explanations thereof are omitted.

[0064] In FIG. 12, after the braking flag is set with the start of the automatic braking control, in step S601, it is determined whether a corrective steering operation (return operation) of the steering has been performed. Specifically, based on the detection information from the steering sensor 33, it is determined whether a corrective steering operation in the direction opposite to the steering direction of the sudden steering has been performed. If it is determined in step S601 that a corrective steering operation is being performed, the process proceeds to step S114. In this case, cancellation of the automatic braking control, restoration processing of the SOC upper limit value, and erasure of the braking flag are performed (steps S114 to S116).

[0065] When proceeding to step S114 due to a corrective steering operation of the steering, in step S114, instead of canceling the automatic braking control, the required braking force PX may be changed so as to reduce the braking force of the automatic braking control. In this case, since the automatic braking control continues, the braking flag may be maintained in the set state.

[0066] ·In the above embodiment, when it is determined that a sudden steering has been performed, the configuration is such that the regenerative control of the traveling motor 23 and the operation control of the braking device 27 are implemented as the automatic braking control. However, as the automatic braking control, a configuration in which only one of the regenerative control of the traveling motor 23 and the operation control of the braking device 27 is implemented may also be used. However, in view of the fact that the regenerative braking by the traveling motor 23 has higher responsiveness than the friction braking of the braking device 27, it is preferable to adopt a configuration in which the regenerative control of the traveling motor 23 is implemented.

[0067] ·When starting the automatic braking control triggered by a sudden steering, rapid charging with a larger charging amount per unit time than normal charging may be temporarily permitted, and the degree of increase (rise) of the regenerative braking force may be increased. In rapid charging, the actual SOC of the battery 21 also rises rapidly, but by raising the SOC upper limit, it is possible to suppress the occurrence of regenerative failure during automatic braking.

[0068] ·In the above-described embodiment, when performing automatic braking control, in order to permit charging that exceeds the SOC upper limit value (normal upper limit value L1) of the battery 21, the SOC upper limit value is configured to be raised from the upper limit value L1 to the upper limit value L2. However, if charging exceeding the upper limit value L1 is permitted, it is also possible to configure to disable the limiter function based on the upper limit value and permit charging up to the full capacity of the battery 21. In particular, it is preferable to disable the above limiter function in a highly urgent situation such as a sudden steering operation in a state where the driver is unconscious.

[0069] ·In order to efficiently recover regenerative power, a configuration is assumed in which the SOC upper limit value of the battery 21 is temporarily raised when the vehicle 10 is traveling downhill. In this configuration, when performing automatic braking control triggered by sudden steering, it may be configured to permit charging of the battery 21 in a range exceeding the SOC upper limit value (downhill use upper limit value) that is raised when the vehicle 10 is traveling downhill. Specifically, for example, in step S107 of FIG. 2, the operation support ECU 20 sets the upper limit value L2 to a value higher than the SOC upper limit value that is raised when the vehicle 10 is traveling downhill. When traveling downhill, battery charging exceeding the normal SOC upper limit value is permitted for the purpose of increasing the amount of recovered regenerative energy, whereas when suddenly steering, battery charging exceeding the normal SOC upper limit value is permitted for the purpose of avoiding danger to the vehicle 10. Comparing when traveling downhill and when suddenly steering, the degree of urgency is different and the occurrence frequency also varies. In view of such circumstances, adopting the configuration shown in this modified example is preferable for improving the safety of the vehicle 10 and protecting the battery 21.

[0070] ·When automatic braking control triggered by sudden steering is performed, in-vehicle electrical loads such as the air conditioner may be forcibly driven to forcibly consume the power stored in the battery 21. By forcibly consuming the power, the chance that the actual SOC of the battery 21 exceeds the SOC upper limit value can be reduced. Also, it is preferable for suppressing regeneration invalidation during automatic braking control.

[0071] ·When raising the SOC upper limit value of the battery 21 at the start of automatic braking control, it is preferable to consider the temperature of the battery 21.

[0072] ·In the above embodiment, the determination of sudden steering is made based on the jerk of steering, but it is not limited to this. The determination of sudden steering may be made based on the speed or acceleration of steering. Also, it is possible to make the determination of sudden steering based on the change in the behavior of the vehicle 10 (for example, the change in yaw).

[0073] ·A changeover switch for switching between a mode in which automatic braking can be executed and a mode in which automatic braking cannot be executed may be provided so that the driver can arbitrarily select each mode.

[0074] ·As the friction brake device, it is also possible to use an electromagnetic drive type brake device instead of the hydraulic brake device 27.

[0075] ·Regarding the automatic brake control shown in the above embodiment, it may be applied to an electrified vehicle (HEV, PHEV) that uses a driving motor and an engine in combination, or to an engine vehicle (ICE).

[0076] The control unit and its method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied by a computer program. Alternatively, the control unit and its method described in the present disclosure may be realized by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. Or, the control unit and its method described in the present disclosure may be realized by one or more dedicated computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured by one or more hardware logic circuits. Also, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer.

Description of Reference Numerals

[0077] 10… Vehicle, 20… Driving support ECU (vehicle control device), 23… Traction motor (braking force generating device), 27… Brake device (braking force generating device).

Claims

1. Applicable to a vehicle (10) capable of traveling by driving a traveling motor (23) and equipped with a friction brake device (27), and capable of generating braking force without depending on the driver's braking operation, using the traveling motor and the friction brake device as a braking force generating device, in the vehicle, a sudden steering determination unit that determines that sudden steering has been performed based on any one of the jerk, acceleration, and speed of the steering angle or a change in yaw; a brake control unit that controls the traveling motor to a regenerative state and commands the operation of the friction brake device in order to generate braking force using the traveling motor and the friction brake device as the braking force generating device when it is determined that the sudden steering has been performed; a braking force determination unit that determines the generation state of the frictional braking force in the friction brake device after the start of control of the traveling motor and the friction brake device based on the determination result that the sudden steering has been performed; comprising the brake control unit is a vehicle control device (20) that shifts from a first state of generating braking force by the traveling motor and the friction brake device to a second state of generating braking force by the friction brake device based on the generation state of the frictional braking force determined by the braking force determination unit.

2. Applicable to a vehicle (10) capable of traveling by driving a traveling motor (23) and equipped with a braking force generating device (23) capable of generating braking force without depending on the driver's braking operation, the vehicle is equipped with a battery (21) that supplies power to the traveling motor, and while the battery can be charged by the regenerative power of the traveling motor, a SOC upper limit value is defined as the upper limit of the SOC of the battery, in the vehicle, a sudden steering determination unit that determines that sudden steering has been performed based on any one of the jerk, acceleration, and speed of the steering angle or a change in yaw; a brake control unit that controls the traveling motor to a regenerative state to generate braking force using the traveling motor as the braking force generating device when it is determined that the sudden steering has been performed; a permission unit that permits charging of the battery exceeding the SOC upper limit value when the traveling motor is controlled to a regenerative state based on the determination result that the sudden steering has been performed; a vehicle control device (20) comprising. **Claim 3**: Applied to a vehicle (10) capable of traveling by driving a traveling motor (23) and equipped with a braking force generating device (23, 27) capable of generating braking force without depending on the driver's braking operation. The vehicle includes a friction braking device (27) and a battery (21) that supplies power to the traveling motor. While the battery can be charged by the regenerative power of the traveling motor, a SOC upper limit value is defined as the upper limit of the SOC of the battery. In the vehicle, a sudden steering determination unit that determines that sudden steering has been performed based on any one of the jerk, acceleration, and speed of the steering angle or a change in yaw. A brake control unit that controls the traveling motor to a regenerative state to generate braking force using the traveling motor as the braking force generating device when it is determined that the sudden steering has been performed. A permission unit that permits charging of the battery exceeding the SOC upper limit value when the traveling motor is controlled to a regenerative state based on the determination result that the sudden steering has been performed. Comprising: The brake control unit: When it is determined that the sudden steering has been performed, to generate braking force using the traveling motor and the friction braking device as the braking force generating device, the traveling motor is controlled to a regenerative state and the operation of the friction braking device is commanded. Furthermore, based on the fact that the SOC of the battery exceeds the SOC upper limit value and the friction braking force is generated by the friction braking device in a situation where charging of the battery exceeding the SOC upper limit value is permitted by the permission unit, a vehicle control device (20) that shifts from a first state of generating braking force by the traveling motor and the friction braking device to a second state of generating braking force by the friction braking device. **Claim 4** When the traveling motor is controlled to a regenerative state based on the determination result that the sudden steering has been performed, an SOC excess determination unit that determines that the SOC of the battery has exceeded the SOC upper limit value due to regeneration of the traveling motor. The vehicle control device according to claim 2 or claim 3, further comprising a regeneration restriction unit that restricts the regenerative power generation of the traveling motor when the operation of the braking force generating device by the brake control unit is released in a state where it is determined by the SOC excess determination unit that the SOC of the battery has exceeded the SOC upper limit value. **Claim 5** When it is determined that the sudden steering has been performed, it includes a loss-of-consciousness determination unit that determines that the driver has lost consciousness as the cause. The permission unit When it is determined that the sudden steering has been performed, the SOC upper limit value is switched from the first upper limit value in the normal state to a second upper limit value higher than the first upper limit value, and by this switching, charging of the battery exceeding the first upper limit value is permitted. Furthermore, when it is determined by the loss-of-consciousness determination unit that the driver has lost consciousness, charging of the battery exceeding the second upper limit value is permitted. The vehicle control device according to any one of claims 2 to 4.

6. In the vehicle, the SOC upper limit value is temporarily raised when driving downhill. The permission unit permits charging of the battery in a range exceeding the SOC upper limit value raised when the vehicle is driving downhill when it is determined that the sudden steering has been performed. The vehicle control device according to any one of claims 2 to 5.

7. Applicable to a vehicle (10) including a braking force generating device (23) capable of generating braking force without depending on the driver's braking operation and enabling driving by driving a traveling motor (23). A regenerative braking force upper limit value is determined as the upper limit of the braking force generated when the traveling motor is in a regenerative state. In the vehicle, a sudden steering determination unit that determines that sudden steering has been performed based on any one of the jerk, acceleration, and speed of the steering angle or the change in yaw, and When it is determined that the sudden steering has been performed, a brake control unit that controls the traveling motor to be in a regenerative state to generate braking force using the traveling motor as the braking force generating device are provided. The brake control unit When generating braking force based on the determination result that the sudden steering has been performed, determines the required braking force that is the braking force, The vehicle control device (20) permits the generation of a regenerative braking force that temporarily exceeds the regenerative braking force upper limit value at the beginning of generating a braking force corresponding to the required braking force.

8. The brake control unit determines the regenerative braking force generated by setting the traveling motor in a regenerative state based on at least one of the road surface condition of the road on which the vehicle is traveling and the turning state of the vehicle. The vehicle control device according to any one of claims 1 to 7.

9. The braking control unit terminates the control of the braking force generator on the condition that a brake operation is performed by the driver after the start of the control of the braking force generator based on the determination result that the sudden steering has been performed. The vehicle control device according to any one of claims 1 to 8.

10. The braking control unit terminates the control of the braking force generator or reduces the braking force on the condition that a return operation for returning the steering in the direction opposite to the sudden steering is performed after the start of the control of the braking force generator based on the determination result that the sudden steering has been performed. The vehicle control device according to any one of claims 1 to 9.

11. A vehicle control program applied to a vehicle (10) capable of traveling by driving a traveling motor (23) and including a friction brake device (27), and capable of generating a braking force without depending on a brake operation by a driver, using the traveling motor and the friction brake device as the braking force generator, to a processor, in the vehicle, a sudden steering determination process for determining that sudden steering has been performed based on any one of the jerk, acceleration, and speed of the steering angle or a change in yaw, when it is determined that the sudden steering has been performed, a brake control process for controlling the traveling motor in a regenerative state and commanding the operation of the friction brake device in order to generate a braking force using the traveling motor and the friction brake device as the braking force generator, a braking force determination process for determining the generation state of the frictional braking force in the friction brake device after the start of the control of the traveling motor and the friction brake device based on the determination result that the sudden steering has been performed, to execute, In the brake control process, based on the generation state of the frictional braking force determined by the braking force determination process, a vehicle control program for shifting from a first state in which the traveling motor and the friction brake device generate a braking force to a second state in which the friction brake device generates a braking force.

12. A vehicle control program applied to a vehicle (10) capable of traveling by driving a traveling motor (23) and including a braking force generator (23) capable of generating a braking force without depending on a brake operation by a driver, The vehicle includes a battery (21) that supplies power to the driving motor, and while the battery can be charged by the regenerative power of the driving motor, a SOC upper limit value is defined as the upper limit of the SOC of the battery, to a processor, in the vehicle, a sudden steering determination process for determining that sudden steering has been performed based on any one of the jerk of the steering angle, the acceleration, and the speed, or a change in yaw, when it is determined that the sudden steering has been performed, a brake control process for controlling the driving motor to a regenerative state so as to generate a braking force using the driving motor as the braking force generating device, when the driving motor is controlled to a regenerative state based on the determination result that the sudden steering has been performed, a permission process for permitting charging of the battery that exceeds the SOC upper limit value, A vehicle control program for execution.

13. A vehicle control program applied to a vehicle (10) capable of traveling by driving a driving motor (23) and including a braking force generating device (23, 27) capable of generating a braking force without depending on a driver's braking operation, the vehicle includes a friction brake device (27) and a battery (21) that supplies power to the driving motor, and while the battery can be charged by the regenerative power of the driving motor, a SOC upper limit value is defined as the upper limit of the SOC of the battery, to a processor, in the vehicle, a sudden steering determination process for determining that sudden steering has been performed based on any one of the jerk of the steering angle, the acceleration, and the speed, or a change in yaw, when it is determined that the sudden steering has been performed, a brake control process for controlling the driving motor to a regenerative state so as to generate a braking force using the driving motor as the braking force generating device, when the driving motor is controlled to a regenerative state based on the determination result that the sudden steering has been performed, a permission process for permitting charging of the battery that exceeds the SOC upper limit value, to execute, in the brake control process, when it is determined that the sudden steering has been performed, in order to generate a braking force using the driving motor and the friction brake device as the braking force generating device, the driving motor is controlled to a regenerative state and the operation of the friction brake device is commanded, Furthermore, in a situation where charging of the battery exceeding the SOC upper limit value is permitted by the permission process, based on the fact that the SOC of the battery exceeds the SOC upper limit value and frictional braking force is generated by the friction braking device, a vehicle control program for shifting from a first state in which braking force is generated by the driving motor and the friction braking device to a second state in which braking force is generated by the friction braking device.

14. A vehicle control program applied to a vehicle (10) including a braking force generating device (23) capable of generating braking force without depending on a driver's braking operation and enabling running by driving a driving motor (23). A regenerative braking force upper limit value is defined as the upper limit of the braking force generated when the driving motor for running is in a regenerative state. To a processor, In the vehicle, a sudden steering determination process for determining that sudden steering has been performed based on any one of the jerk, acceleration, and speed of the steering angle or a change in yaw, and When it is determined that the sudden steering has been performed, a brake control process for controlling the driving motor for running to a regenerative state so as to generate braking force using the driving motor for running as the braking force generating device are executed, In the brake control process, When generating braking force based on the determination result that the sudden steering has been performed, a required braking force that is the braking force is determined, A vehicle control program that permits the generation of a regenerative braking force that temporarily exceeds the regenerative braking force upper limit value at the beginning of generating a braking force corresponding to the required braking force.

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