JP6112309B2 - Vehicle behavior control device - Google Patents

Description

  The present invention relates to a vehicle behavior control device, and more particularly to a vehicle behavior control device that controls the behavior of a vehicle in which front wheels are steered.

  Conventionally, devices that control the behavior of a vehicle in a safe direction when the behavior of the vehicle becomes unstable due to slip or the like (such as a skid prevention device) are known. Specifically, when the vehicle is cornered, it is detected that understeer or oversteer behavior has occurred in the vehicle, and an appropriate deceleration is applied to the wheels to suppress them. A stability control system) is known (see, for example, Patent Document 1).

  On the other hand, unlike the above-described control for improving safety in a driving state where the behavior of the vehicle becomes unstable, a series of operations (braking, It is known to adjust the load applied to the front wheel, which is the steering wheel, by adjusting the deceleration during cornering so that the steering, turning, acceleration, steering return, etc.) are natural and stable. (For example, refer to Patent Document 2).

JP 2010-184658 A JP 2011-88576 A

  However, for example, in the vehicle motion control device of Patent Document 2, vehicle running control during cornering is detected, and vehicle deceleration control is performed by controlling the hydraulic brake system according to the detection result. Since this hydraulic brake system has a structure in which play is provided between parts, there is a time lag between when a control value is input to the hydraulic brake system and when deceleration occurs in the vehicle. For this reason, it is difficult for conventional devices to perform vehicle deceleration control at an appropriate timing. Therefore, in the apparatus of Patent Document 2, the curve ahead of the vehicle is estimated using a camera, and control of the hydraulic brake system is started before entering the curve, resulting in an increase in complexity and cost of the apparatus. .

  Accordingly, the present inventors have conducted intensive research and found that the control of the driver's operation during cornering can be controlled by controlling the driving force of the vehicle without using a brake system. Furthermore, the present inventors have made it possible to adjust the deceleration by adjusting the regenerative electric power, and by adjusting the regenerative electric power, particularly in the electrically driven vehicle. It was discovered that the driving force can be adjusted directly by reducing motor torque (= motor regeneration) without causing a time lag that occurs when using the system.

  Based on these findings, the inventors have increased the amount of driving force reduction of the vehicle and reduced the rate of increase of the vehicle as the yaw rate related amount related to the yaw rate of the vehicle increases. A vehicle behavior control device that performs so-called steering support control to reduce force has been proposed (Japanese Patent Application No. 2013-034266). According to this device, when the steering of the vehicle is started and the yaw rate related amount of the vehicle starts to increase, the driving force reduction amount is rapidly increased, so that the deceleration is rapidly caused in the vehicle at the start of the steering of the vehicle. A sufficient load can be quickly applied to the front wheels, which are the steering wheels. As a result, the frictional force between the front wheels, which are the steering wheels, and the road surface increase, and the cornering force of the front wheels increases, so that the turning ability of the vehicle at the beginning of the curve entry can be improved, and the response to the steering turning operation Can be improved.

  However, when the vehicle behavior control apparatus performs the above-described DSC control together with the steering support control, depending on the friction coefficient of the road surface on which the vehicle is traveling and the traveling state of the vehicle, the steering support control and the DSC control may be different. There are situations where they operate simultaneously, and in this case it becomes a problem which control should be given priority.

  The present invention has been made to solve the above-described problems of the prior art, and can appropriately determine the conditions under which the steering support control is executed and the conditions under which the DSC control is executed. It is an object of the present invention to provide a vehicle behavior control device that can preferentially execute control that is highly necessary in accordance with traveling conditions.

In order to achieve the above object, a vehicle behavior control apparatus according to the present invention is a vehicle behavior control apparatus that controls the behavior of a vehicle whose front wheels are steered, and acquires a yaw rate related quantity related to the yaw rate of the vehicle. Related amount acquisition means, road surface friction coefficient estimation means for estimating the friction coefficient of the road surface on which the vehicle is traveling, and yaw rate related information acquired by the yaw rate related amount acquisition means when the road surface friction coefficient is equal to or less than a first threshold value The driving force reduction means for reducing the driving force of the vehicle so as to increase the driving force reduction amount of the vehicle as the amount increases and the increase rate of the increasing amount, and the road surface friction coefficient is equal to or less than the second threshold value And a first threshold based on the driving force control means for controlling the driving force of the vehicle so that the actual yaw rate of the vehicle becomes the target yaw rate, and the vehicle speed, steering speed, and steering angle of the vehicle. With determining, and having a threshold value determining means for determining a second threshold based on the yaw rate of the vehicle, a.
In the present invention configured as described above, the threshold value determining means determines the first threshold value based on the vehicle speed, the steering speed, and the steering angle of the vehicle, and determines the second threshold value based on the yaw rate of the vehicle. Therefore, when there is a high need to improve the driver's operational feeling during cornering according to the vehicle speed, steering speed, and steering angle of the vehicle, the amount of reduction in the driving force of the vehicle increases as the yaw rate related amount increases. In addition, it is necessary to perform steering support control that improves the turning performance of the vehicle by reducing the driving force of the vehicle so as to reduce the increase rate of the increase amount, and to maintain the stability of the behavior of the vehicle according to the yaw rate of the vehicle. When the performance is high, the first threshold value and the second threshold value are determined so as to execute DSC control for controlling the driving force of the vehicle so that the actual yaw rate matches the target yaw rate. As a result, the conditions under which the steering support control is executed and the conditions under which the DSC control are executed can be appropriately determined, and the highly necessary control is preferentially executed in accordance with the traveling state of the vehicle. can do.

In the present invention, it is preferable that the threshold value determining unit determines the first threshold value so that the first threshold value increases as the product of the vehicle speed, the steering speed, and the steering angle of the vehicle increases.
In the present invention configured as described above, the threshold value determining means determines the first threshold value so that the first threshold value increases as the product of the vehicle speed, the steering speed, and the steering angle of the vehicle increases. In a driving situation in which the product of the vehicle speed, steering speed, and steering angle is large, that is, in a driving situation in which a larger cornering force is required to turn the vehicle with high responsiveness according to the driver's steering, the first threshold value is used. As a result, the steering support control can be easily performed even in a situation where the road surface friction coefficient is high. Thus, the steering support control is surely executed when necessary according to the traveling state of the vehicle. be able to.

In the present invention, it is preferable that the threshold value determining unit determines the second threshold value so that the second threshold value increases as the yaw rate of the vehicle increases.
In the present invention configured as described above, the threshold value determining means determines the second threshold value so that the second threshold value increases as the vehicle yaw rate increases. That is, in a driving situation in which understeer or oversteer behavior tends to occur in the vehicle, by increasing the second threshold value, DSC control can be easily performed even in a situation where the road surface friction coefficient is high. The DSC control can be surely executed when necessary according to the traveling state of the vehicle.

In the present invention, it is preferable that the driving force reducing unit does not reduce the driving force of the vehicle when the driving force of the vehicle is controlled by the driving force control unit.
In the present invention configured as described above, the driving force reducing means does not execute the steering support control when the DSC control is executed by the driving force control means, and therefore, in a driving situation where the DSC control needs to be executed. The DSC control can be executed with priority over the steering support control, and the stability of the behavior of the vehicle can be given priority over the operational feeling of the driver during cornering of the vehicle.

In the present invention, it is preferable that the vehicle is an electrically driven vehicle including a motor that drives wheels and a battery that supplies electric power to the motor and collects regenerative electric power generated by the motor. The reduction means reduces the driving force of the vehicle by controlling the amount of regenerative power generated by the motor in accordance with the amount related to the yaw rate, and the driving force control means responds to the difference between the actual yaw rate of the vehicle and the target yaw rate. Thus, the driving power of the vehicle is controlled by controlling the amount of power supplied to the motor or the amount of regenerative power generated by the motor.
In the present invention configured as described above, the driving force reduction means reduces the torque of the motor according to the vehicle yaw rate related amount, and the driving force control means responds to the difference between the actual yaw rate of the vehicle and the target yaw rate. Since the motor torque is controlled, the driving force of the vehicle can be directly controlled. Therefore, compared with the case where the driving force of the vehicle is controlled by controlling the hydraulic brake unit, the response of the driving force control can be improved, and the behavior of the vehicle can be controlled more directly.

  According to the vehicle behavior control apparatus of the present invention, the conditions under which the steering support control is executed and the conditions under which the DSC control is executed can be appropriately determined, and the control that is highly necessary according to the traveling state of the vehicle. Can be preferentially executed.

1 is a block diagram showing an overall configuration of a vehicle equipped with a vehicle behavior control apparatus according to an embodiment of the present invention. 1 is a block diagram showing an electrical configuration of a vehicle behavior control apparatus according to an embodiment of the present invention. It is a flowchart of the behavior control operation state determination process in which the vehicle behavior control apparatus according to the embodiment of the present invention determines the operation states of the steering support control and the DSC control. 5 is a map that is referred to when a driving force control unit according to an embodiment of the present invention determines a threshold value of a road surface μ that is a reference for determining an operation state of steering support control and DSC control. It is a map which illustrates the combination of the operation state of steering support control of the vehicle behavior control apparatus by embodiment of this invention, and DSC control. It is a flowchart of the steering support control process in which the vehicle behavior control apparatus according to the embodiment of the present invention supports the steering of the driver. It is a map referred when the driving force control part by embodiment of this invention determines basic control intervention torque based on target yaw acceleration.

Hereinafter, a vehicle behavior control apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.
First, a vehicle equipped with a vehicle behavior control apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing an overall configuration of a vehicle equipped with a vehicle behavior control apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, reference numeral 1 denotes a vehicle on which the vehicle behavior control apparatus according to the present embodiment is mounted. The vehicle 1 has a battery 2 (secondary battery) mounted as a power source, and the front wheels are steered. An electric vehicle or a hybrid vehicle. A motor 6 for driving the drive wheels 4 (left and right front wheels in the example of FIG. 1) is mounted on the front of the vehicle body. The DC power supplied from the battery 2 is converted into AC power and supplied to the motor 6, and the regenerative power generated by the motor 6 is converted into DC power and supplied to the battery 2 to charge the battery 2. An inverter 8 is disposed in the vicinity of the motor 6.

The vehicle 1 also includes a steering angle sensor 12 that detects the rotation angle of the steering wheel 10, a vehicle speed sensor 14 that detects the vehicle speed, and a yaw rate that detects the rotation angular velocity (yaw rate) of the vehicle 1 around the vertical axis (yaw axis). A sensor 16 and a lateral acceleration sensor 18 that detects the lateral acceleration of the vehicle 1 are included. Each of these sensors outputs the detected value to the vehicle behavior control apparatus 20.
Furthermore, the vehicle 1 includes an indicator 22 that displays information related to behavior control of the vehicle 1 by the vehicle behavior control device 20.
The battery 2 includes a battery state detection unit 24 that detects the SOC (State Of Charge) and temperature of the battery 2.

Next, an electrical configuration of the vehicle behavior control apparatus 20 according to the embodiment of the present invention will be described with reference to FIG. FIG. 2 is a block diagram showing an electrical configuration of the vehicle behavior control apparatus 20 according to the embodiment of the present invention.
The vehicle behavior control device 20 includes a yaw acceleration calculation unit 26 that calculates a target yaw acceleration of the vehicle 1, a road surface μ estimation unit 28 that estimates a friction coefficient (road surface μ) of a road surface on which the vehicle 1 is traveling, And a driving force control unit 30 that reduces the driving force of the vehicle 1 according to one target yaw acceleration.
The vehicle behavior control device 20 includes a steering angle detected by the steering angle sensor 12, a vehicle speed detected by the vehicle speed sensor 14, a yaw rate detected by the yaw rate sensor 16, a lateral acceleration detected by the lateral acceleration sensor 18, and a battery state detection. The SOC and temperature of the battery 2 detected by the unit 24 are input.

The yaw acceleration calculation unit 26 calculates the target yaw rate of the vehicle 1 based on the steering angle input from the steering angle sensor 12 and the vehicle speed input from the vehicle speed sensor 14, and based on the target yaw rate, Calculate yaw acceleration.
The road surface μ estimation unit 28 estimates the road surface μ of the road surface on which the vehicle 1 is traveling based on the yaw rate input from the yaw rate sensor 16 and the lateral acceleration input from the lateral acceleration sensor 18.
Specifically, the driving force control unit 30 is configured so that the yaw rate detected by the yaw rate sensor 16 coincides with the calculated target yaw rate so as to suppress understeer or oversteer behavior in the vehicle 1. Next, the driving force of each driving wheel 4 of the vehicle 1 is controlled (DSC control). Further, the driving force control unit 30 determines a torque reduction amount (that is, a driving force reduction amount) of the motor 6 based on the calculated target yaw acceleration, the vehicle speed, and the state of the battery 2 in order to support steering by the driver. Then, the amount of regenerative power generated by the motor 6 is controlled so as to realize the torque reduction amount of the motor 6 (steering support control). Further, the driving force control unit 30 outputs information indicating whether or not the driving force control unit 30 can control the driving force of the motor 6 to the indicator 22.
The yaw acceleration calculation unit 26, the road surface μ estimation unit 28, and the driving force control unit 26 are activated by the CPU, various programs interpreted on the CPU (basic control programs such as the OS, and the OS. Including an application program for realizing a specific function) and a computer having an internal memory such as a ROM or RAM for storing the program and various data.

Next, behavior control operation state determination processing performed by the vehicle behavior control device 20 will be described with reference to FIGS. 3 to 5.
FIG. 3 is a flowchart of behavior control operation state determination processing performed by the vehicle behavior control apparatus 20 according to the embodiment of the present invention. FIG. 4 is a flowchart illustrating the steering support control and DSC performed by the driving force control unit 30 according to the embodiment of the present invention. FIG. 5 is a map that is referred to when determining the threshold value of the road surface μ serving as a reference for determining the operation state of the control. FIG. 5 is a diagram illustrating the steering support control and the DSC control of the vehicle behavior control apparatus 20 according to the embodiment of the present invention. It is a map which illustrates the combination of an operating state.

The behavior control operation state determination process is activated and executed repeatedly when the ignition of the vehicle 1 is turned on and the vehicle behavior control device 20 is powered on.
As shown in FIG. 3, when the behavior control operation state determination process is started, in step S <b> 1, the driving force control unit 30 detects the steering angle detected by the steering angle sensor 12, the vehicle speed detected by the vehicle speed sensor 14, And the yaw rate detected by the yaw rate sensor 16 is acquired.

Next, in step S2, the driving force control unit 30 determines a threshold value (steering support threshold value) of the road surface μ serving as a reference for determining ON / OFF of the steering support control based on the vehicle speed and the steering angle acquired in step S1. At the same time, based on the yaw rate acquired in step S1, a threshold value (DSC threshold value) of the road surface μ serving as a reference for determining ON / OFF of the DSC control is determined.
Specifically, the driving force control unit 30 calculates a steering speed based on the steering angle acquired in step S1, and calculates the product of this steering speed and the vehicle speed and steering angle acquired in step S1. Then, a steering support threshold value corresponding to the product of the calculated vehicle speed, steering speed, and steering angle is determined with reference to a map showing the relationship between the product of the vehicle speed, the steering speed, and the steering angle, and the steering support threshold value.
Further, the driving force control unit 30 refers to a map showing the relationship between the yaw rate of the vehicle 1 and the DSC threshold value, and determines the DSC threshold value corresponding to the yaw rate acquired in step S1.
FIG. 4 is a map that is referred to when the driving force control unit 30 determines the steering support threshold and the DSC threshold. FIG. 4A is a map that is referred to when determining the steering support threshold. FIG. ) Is a map referred to when determining the DSC threshold. As shown in FIG. 4A, the steering support threshold increases as the product of the vehicle speed, the steering speed, and the steering angle increases. As shown in FIG. 4B, the DSC threshold increases as the yaw rate increases.

  Next, in step S <b> 3, the road surface μ estimation unit 28 estimates the road surface μ of the road surface on which the vehicle 1 is traveling based on the yaw rate input from the yaw rate sensor 16 and the lateral acceleration input from the lateral acceleration sensor 18. To do.

Next, in step S4, the driving force control unit 30 determines whether or not the road surface μ estimated in step S3 is smaller than the DSC threshold determined in step S2. As a result, when the estimated road surface μ is smaller than the DSC threshold, the process proceeds to step S5, where the DSC control is turned on, and the steering support control is turned off regardless of whether the estimated road surface μ is smaller than the steering support threshold. .
For example, as shown by circles in FIGS. 5A and 5B, when the road surface μ estimated in step S3 is smaller than the DSC threshold corresponding to the yaw rate acquired in step S1, the process proceeds to step S3. Regardless of whether or not the estimated road surface μ is smaller than the steering support threshold corresponding to the product of the vehicle speed, the steering speed, and the steering angle calculated in step S2, the steering support control is turned OFF.
In other words, in a driving situation where it is necessary to turn on the DSC control, it is considered that it is more necessary to prioritize the stability of the behavior of the vehicle 1 than the driver's operational feeling when the vehicle 1 is cornering. It is made to operate in preference to steering support control.

On the other hand, if the estimated road surface μ is not smaller than the DSC threshold value in step S4 (is greater than or equal to the DSC threshold value), the process proceeds to step S6, and the driving force control unit 30 determines the road surface μ estimated in step S3 in step S2. It is determined whether or not the steering support threshold value is smaller. As a result, when the estimated road surface μ is smaller than the steering support threshold value, the process proceeds to step S7, and the driving force control unit 30 turns off the DSC control and turns on the steering support control.
For example, as indicated by a circle in FIG. 5C, the road surface μ estimated in step S3 is larger than the DSC threshold corresponding to the yaw rate acquired in step S1, and the road surface μ estimated in step S3 is If it is smaller than the steering support threshold corresponding to the product of the vehicle speed, steering speed and steering angle calculated in S2, the DSC control is turned off and the steering support control is turned on.
That is, in a driving situation where the DSC control can be turned off, it is considered that there is a high need to improve the driver's operational feeling during cornering of the vehicle 1, so the steering support control is activated.

In step S6, if the estimated road surface μ is not smaller than the steering support threshold (is equal to or greater than the steering support threshold), the process proceeds to step S8, and the driving force control unit 30 turns off the DSC control and the steering support control.
For example, as indicated by a circle in FIG. 5D, the road surface μ estimated in step S3 is larger than the DSC threshold corresponding to the yaw rate acquired in step S1, and the road surface μ estimated in step S3 is When it is larger than the steering support threshold value corresponding to the product of the vehicle speed, the steering speed, and the steering angle calculated in S2, the DSC control is turned off and the steering support control is turned off.

  After step S5, S7, or S8, the vehicle behavior control apparatus 20 ends the behavior control operation state determination process.

  When the DSC control is turned on in the behavior control operation state determination process described above, the driving force control unit 30 specifically suppresses the understeer or oversteer behavior when it occurs in the vehicle 1. Controls the driving force of each drive wheel 4 of the vehicle 1 so that the yaw rate detected by the yaw rate sensor 16 matches the calculated target yaw rate. Various methods in the conventional DSC control can be used for the specific calculation method of the target yaw rate and the specific control content of the driving force of each driving wheel 4.

When the steering support control is ON, the driving force control unit 30 performs the steering support control for supporting the steering by the driver. Here, the steering support control process will be described with reference to FIGS. 6 and 7.
FIG. 6 is a flowchart of the steering support control process performed by the vehicle behavior control apparatus 20 according to the embodiment of the present invention. FIG. 7 is a flowchart illustrating the basic operation of the driving force control unit 30 according to the embodiment of the present invention based on the target yaw acceleration. It is a map referred when determining a control intervention torque. In FIG. 7, the horizontal axis indicates the target yaw acceleration, and the vertical axis indicates the basic control intervention torque.

The steering support control process is activated and repeatedly executed when the steering support control is turned on in the behavior control operation state determination process.
As shown in FIG. 6, when the steering support control process is started, in step S <b> 11, the driving force control unit 30 acquires the SOC and temperature of the battery 2 detected by the battery state detection unit 24.

  Next, in step S12, the driving force control unit 30 determines whether or not the battery 2 can recover the regenerative power generated by the motor 6 based on the state of the battery 2 acquired in step S11. The driving force control unit 30 determines that the battery 2 can recover the regenerative power generated by the motor 6 when the SOC of the battery 2 is equal to or lower than a predetermined value and the temperature of the battery 2 is equal to or lower than the predetermined temperature.

  As a result, when the battery 2 can recover the regenerative power generated by the motor 6, the process proceeds to step S13, and the yaw acceleration calculation unit 26 receives the steering angle input from the steering angle sensor 12 and the vehicle speed sensor 14. The target yaw rate of the vehicle 1 is calculated based on the vehicle speed, and the target yaw acceleration of the vehicle 1 is calculated based on the target yaw rate. Specifically, the yaw acceleration calculation unit 26 calculates a target yaw rate by multiplying the steering angle input from the steering angle sensor 12 by a coefficient corresponding to the vehicle speed input from the vehicle speed sensor 14, and calculates the target yaw rate. The target yaw acceleration is calculated by time differentiation.

Next, in step S14, the driving force control unit 30 determines a torque reduction amount (basic control intervention torque) of the motor 6 based on the target yaw acceleration calculated by the yaw acceleration calculation unit 26 in step S13. This basic control intervention torque is a torque reduction amount for causing an appropriate deceleration in the vehicle 1 traveling on the curve, and is determined without taking into consideration the vehicle speed and the regenerative electric energy that can be recovered by the battery 2. Value.
Specifically, the driving force control unit 30 refers to a map showing the relationship between the target yaw acceleration and the basic control intervention torque, and the basic control intervention corresponding to the target yaw acceleration calculated by the yaw acceleration calculation unit 26 in step S13. Specify torque.
As shown in FIG. 7, as the target yaw acceleration increases, the basic control intervention torque corresponding to the target yaw acceleration gradually approaches a predetermined upper limit value (12 Nm in FIG. 4). That is, the driving force control unit 30 controls to increase the basic control intervention torque and reduce the increase rate of the increase amount as the target yaw acceleration increases.

Next, in step S15, the driving force control unit 30 determines the control intervention acceptable torque based on the state of the battery 2 acquired in step S11. This control intervention acceptable torque is a torque reduction amount of the motor 6 corresponding to the maximum regenerative power amount that can be recovered by the battery 2.
Specifically, the driving force control unit 30 specifies the regenerative power amount that the battery 2 can recover from the motor 6 and the maximum current that can be supplied to the battery 2 based on the SOC and temperature of the battery 2, and these regenerative power. Based on the amount and the maximum current, the regenerative power allowed for the motor 6 is calculated. Then, a regenerative torque corresponding to the allowable regenerative power is calculated as a control intervention acceptable torque.

  Next, in step S16, the driving force control unit 30 determines a corrected control intervention torque obtained by correcting the basic control intervention torque determined by the driving force control unit 30 in step S14. Specifically, the driving force control unit 30 determines the smaller one of the basic control intervention torque and the control intervention acceptable torque determined in step S15 as the corrected control intervention torque.

  Next, in step S17, the driving force control unit 30 controls the amount of regenerative power generated by the motor 6 so that the torque reduction amount of the motor 6 becomes the correction control intervention torque determined in step S16. Specifically, the driving force control unit 30 controls the regenerative circuit in the inverter 8 so that the motor 6 generates regenerative power corresponding to the correction control intervention torque determined in step S16. As a result, the driving force control unit 30 reduces the driving force having a magnitude corresponding to the correction control intervention torque.

  In step S12, when the battery 2 cannot recover the regenerative power generated by the motor 6 (that is, when the SOC of the battery 2 is higher than a predetermined value or when the temperature of the battery 2 is higher than the predetermined temperature), step Proceeding to S <b> 18, the driving force control unit 30 causes the indicator 22 to display information indicating that the vehicle behavior control device 20 cannot execute control for reducing the driving force of the vehicle 1.

  After step S17 or S18, the vehicle behavior control apparatus 20 ends the steering support control process.

Next, further modifications of the embodiment of the present invention will be described.
In the embodiment described above, it has been described that the vehicle 1 equipped with the vehicle behavior control device 20 is equipped with the battery 2 as a power source. However, the vehicle behavior control is performed on the vehicle 1 equipped with a gasoline engine or a diesel engine as a power source. The device 20 may be mounted. In this case, the driving force control unit 30 controls the fuel injection amount and the transmission according to the yaw acceleration, and controls the driving force by the gasoline engine or the diesel engine.

In the above-described embodiment, it has been described that the driving force control unit 30 determines the torque reduction amount of the motor 6 based on the target yaw acceleration calculated by the yaw acceleration calculation unit 26. However, the driving force control unit 30 relates to the yaw rate of the vehicle 1. The torque reduction amount of the motor 6 may be determined based on other parameters.
For example, the yaw acceleration calculation unit 26 calculates the yaw acceleration generated in the vehicle 1 based on the yaw rate input from the yaw rate sensor 16, and the driving force control unit 30 calculates the motor based on the yaw acceleration calculated in this way. A torque reduction amount of 6 may be determined. In this case, the driving force control unit 30 controls to increase the torque reduction amount of the motor 6 of the vehicle 1 and reduce the increase rate of the increase amount as the yaw acceleration generated in the vehicle 1 increases.
Alternatively, the lateral acceleration sensor 18 may detect a lateral acceleration generated as the vehicle 1 turns, and the driving force control unit 30 may determine a torque reduction amount of the motor 6 based on the lateral acceleration. In this case, the driving force control unit 30 controls to increase the torque reduction amount of the motor 6 of the vehicle 1 and reduce the increase rate of the increase amount as the lateral acceleration generated in the vehicle 1 increases.

  Next, the effect of the vehicle behavior control apparatus 20 according to the above-described embodiment of the present invention and the modification of the embodiment of the present invention will be described.

  First, the driving force control unit 30 of the vehicle behavior control apparatus 20 is based on the vehicle speed, the steering speed, and the steering angle of the vehicle 1, and the threshold value of the road surface μ (steering support) that serves as a reference for determining the ON / OFF of the steering support control. Threshold value) and a threshold value (DSC threshold value) of the road surface μ that is a reference for determining ON / OFF of the DSC control based on the yaw rate of the vehicle 1 is determined. Therefore, the vehicle speed, steering speed, and steering angle of the vehicle 1 are determined. When it is highly necessary to improve the driver's operational feeling during cornering, the steering support control is executed, and when it is highly necessary to maintain the stability of the behavior of the vehicle 1 according to the yaw rate of the vehicle 1. Can determine the steering support threshold value and the DSC threshold value so as to execute the DSC control, whereby the conditions under which the steering support control is executed and the DSC control are executed. It is possible to appropriately determine the condition to be performed, and it is possible to preferentially execute control that is highly necessary in accordance with the traveling state of the vehicle 1.

  In particular, the driving force control unit 30 determines the steering support threshold so that the steering support threshold increases as the product of the vehicle speed, the steering speed, and the steering angle of the vehicle 1 increases. In a driving situation in which the product of the steering angle is large, that is, in a driving situation in which a larger cornering force is required to turn the vehicle 1 with high responsiveness according to the driver's steering, the road surface is increased by increasing the steering support threshold. Steering support control can be easily performed even in a situation where μ is high, and thus steering support control can be reliably executed when necessary according to the traveling state of the vehicle 1.

  Further, since the driving force control unit 30 determines the DSC threshold value so that the DSC threshold value increases as the yaw rate of the vehicle 1 increases, a driving situation in which the yaw rate of the vehicle 1 is large, that is, the vehicle 1 is understeered or oversteered. In a driving situation in which behavior is likely to occur, the DSC threshold value can be increased to facilitate execution of DSC control even in a situation where the road surface μ is high. When this is necessary depending on the driving situation of the vehicle 1 DSC control can be executed reliably.

  Further, the driving force control unit 30 turns off the steering support control in a traveling situation where the DSC control needs to be turned on regardless of whether the road surface μ is smaller than the steering support threshold or not, so the DSC control is turned on. DSC control can be prioritized over steering support control in a driving situation that needs to be set, and the stability of the behavior of the vehicle 1 may be prioritized over the driver's operational feeling during cornering of the vehicle 1. it can.

  The vehicle 1 is an electrically driven vehicle having a motor 6 that drives wheels and a battery 2 that supplies electric power to the motor 6 and collects regenerative power generated by the motor 6. Reduces the driving force of the vehicle 1 by controlling the amount of regenerative power generated by the motor 6 in accordance with the target yaw acceleration. That is, the driving force control unit 30 reduces the torque of the motor 6 according to the target yaw acceleration of the vehicle 1 and controls the torque of the motor 6 according to the difference between the actual yaw rate of the vehicle 1 and the target yaw rate. Thus, the driving force of the vehicle 1 can be controlled. Therefore, compared with the case where the driving force of the vehicle 1 is controlled by controlling the hydraulic brake unit, the response of the driving force control can be improved, and the behavior of the vehicle 1 can be controlled more directly.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Battery 4 Driving wheel 6 Motor 8 Inverter 10 Steering wheel 12 Steering angle sensor 14 Vehicle speed sensor 16 Yaw rate sensor 18 Lateral acceleration sensor 20 Vehicle behavior control device 22 Indicator 24 Battery state detection part 26 Yaw acceleration calculation part 28 Road surface micro estimation 30 Driving force control unit

Claims (5)

In a vehicle behavior control device for controlling the behavior of a vehicle in which front wheels are steered,
A yaw rate related amount acquisition means for acquiring a yaw rate related amount related to the yaw rate of the vehicle;
Road surface friction coefficient estimating means for estimating the friction coefficient of the road surface on which the vehicle is traveling;
When the road surface friction coefficient is less than or equal to the first threshold, the vehicle driving force reduction amount increases and the increase rate of the increase amount decreases as the yaw rate related amount acquired by the yaw rate related amount acquisition means increases. Driving force reducing means for reducing the driving force of the vehicle so as to
Driving force control means for controlling the driving force of the vehicle so that the actual yaw rate of the vehicle becomes a target yaw rate when the road surface friction coefficient is equal to or less than a second threshold;
Threshold value determining means for determining the first threshold value based on the vehicle speed, the steering speed, and the steering angle of the vehicle and determining the second threshold value based on the yaw rate of the vehicle. A vehicle behavior control device.   2. The vehicle behavior according to claim 1, wherein the threshold value determining unit determines the first threshold value so that the first threshold value increases as a product of a vehicle speed, a steering speed, and a steering angle of the vehicle increases. Control device.   The vehicle behavior control apparatus according to claim 1 or 2, wherein the threshold value determining means determines the second threshold value so that the second threshold value increases as the yaw rate of the vehicle increases.   4. The vehicle behavior control according to claim 1, wherein the driving force reducing unit does not reduce the driving force of the vehicle when the driving force of the vehicle is controlled by the driving force control unit. 5. apparatus. The vehicle is an electrically driven vehicle having a motor that drives wheels, and a battery that supplies power to the motor and collects regenerative power generated by the motor,
The driving force reducing means reduces the driving force of the vehicle by controlling the amount of regenerative power generated by the motor according to the yaw rate related amount,
The driving force control means controls the driving force of the vehicle by controlling the amount of electric power supplied to the motor or the amount of regenerative electric power generated by the motor according to the difference between the actual yaw rate of the vehicle and the target yaw rate. The vehicle behavior control device according to claim 1, wherein the vehicle behavior control device is controlled.

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