JP2015085820A - Behavior control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a behavior control device for a vehicle that can control a vehicle behavior so as to enable a driver to perform a natural and stable operation during cornering of the vehicle without making the driver feel discomfort such as dragging of braking.SOLUTION: A behavior control device 18 for a vehicle controlling the behavior of the vehicle of which front wheels are steered comprises: a yaw acceleration calculation unit 24 which calculates a target yaw acceleration of the vehicle; and a driving force control unit 26 which controls a vehicle driving force to decrease according to the target yaw acceleration calculated by the yaw acceleration calculation unit. The driving force control unit determines reduction amount of the vehicle driving force to increase the reduction amount and decrease the increase rate thereof as the yaw acceleration increases, and corrects the reduction amount of the driving force determined by the driving force control unit to decrease as a requested driving force for the vehicle increases.

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, it is known to detect that understeer or oversteer behavior has occurred in the vehicle during cornering of the vehicle, and to impart appropriate deceleration to the wheels to suppress them. ing.

  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 1).

JP 2011-88576 A

  However, for example, in the vehicle motion control device disclosed in Patent Document 1, the vehicle traveling state during cornering is detected, and the 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 1, the curve ahead of the vehicle is estimated using a camera, and control of the hydraulic brake system is started before entering the curve. This causes 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 for reducing 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, the more the driver needs the driving force of the vehicle, and the more the accelerator pedal is depressed, the more sensitive the driver is to changes in vehicle speed, so steering is performed when the accelerator pedal is depressed greatly (for example, When the accelerator pedal is not fully depressed at the time of merging at the highway entrance, lane change during climbing, S-curve while climbing, etc. (for example, lightly put the foot on the accelerator pedal) If the driving force of the vehicle is reduced to the same extent as a curve or lane change while driving at a constant speed on a flat ground, it feels uncomfortable as if the brake is dragged.

  The present invention has been made to solve the above-described problems of the prior art, and the driver's operation during cornering of the vehicle is natural without causing the driver to feel uncomfortable feeling that the brake is dragged. An object of the present invention is to provide a vehicle behavior control apparatus that can control the behavior of a vehicle so as to be stable.

In order to achieve the above object, a vehicle behavior control device according to the present invention is a vehicle behavior control device that controls the behavior of a vehicle whose front wheels are steered. And a driving force control unit that controls to reduce the driving force of the vehicle in accordance with the yaw rate related amount acquired by the yaw rate related amount acquisition unit. As the amount increases, driving force reduction amount determining means for determining the driving force reduction amount so as to increase the driving force reduction amount of the vehicle and reduce the increase rate of the increasing amount, and the required driving force for the vehicle increases. And a driving force reduction amount correcting means for correcting the driving force reduction amount determined by the driving force reduction amount determining means so as to decrease.
In the present invention configured as described above, when the steering of the vehicle is started and the yaw rate related amount of the vehicle starts to increase, the driving force control means quickly increases the driving force reduction amount. In this case, the vehicle can be quickly decelerated and 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. Further, the driving force control means reduces the rate of increase in the driving force reduction amount of the vehicle as the yaw rate related amount increases, so that the deceleration generated in the vehicle during curve driving does not become excessive and decreases at the end of steering. Speed can be reduced quickly. Therefore, it is possible to prevent the driver from feeling a drag of reducing the driving force when exiting the curve. Further, since the driving force reduction amount correction means corrects the driving force reduction amount determined by the driving force reduction amount determination means to decrease as the required driving force for the vehicle increases, the driving force reduction amount for the vehicle increases. The deceleration generated in the vehicle can be reduced, thereby preventing the driver from feeling uncomfortable as if the driver is stepping on the accelerator pedal and is sensitive to changes in the vehicle speed, such as dragging the brake. As described above, according to the vehicle behavior control device of the present invention, the behavior of the vehicle is controlled so that the driver's operation becomes natural and stable without cornering the vehicle without causing the driver to feel uncomfortable. Can do.

In the present invention, it is preferable that the driving force reduction amount correction unit decreases the driving force reduction amount determined by the driving force reduction amount determination unit as the required driving force increases when the required driving force is less than a predetermined value. When the required driving force is greater than or equal to a predetermined value, the driving force reduction amount determined by the driving force reduction amount determining means is corrected to a certain minimum value.
In the present invention configured as described above, when the required driving force is a predetermined value or more, a minimum deceleration is generated in the vehicle according to the yaw rate related amount of the vehicle or the deceleration is not generated. When the required driving force is less than the predetermined value, the deceleration generated in the vehicle increases as the required driving force decreases.Therefore, the driver depresses the accelerator pedal greatly, and if the driver is sensitive to changes in the vehicle speed, the brake is applied. If the driver does not depress the accelerator pedal greatly and is not so sensitive to changes in the vehicle speed, the smaller the accelerator pedal depressing amount, the more the response to the steering turning operation. Can be improved.

In the present invention, it is preferable that the driving force control means performs control to reduce the driving force of the vehicle when the absolute value of the steering angle of the vehicle is increased.
In the present invention configured as described above, when the absolute value of the steering angle of the vehicle is increased due to the steering turning operation, the driving force of the vehicle is reduced, so that the steering turning operation is performed. Thus, a sufficient load can be applied to the front wheels, which are the steering wheels, and the responsiveness of the vehicle to the steering turning operation can be improved with certainty.

In the present invention, it is preferable that the driving force reduction amount correction unit multiplies the driving force reduction amount determined by the driving force reduction amount determination unit by a coefficient set so as to decrease as the required driving force increases. Thus, the driving force reduction amount is corrected.
In the present invention configured as described above, the driving force reduction amount correcting means corrects the driving force reduction amount determined by the driving force reduction amount determining means so as to decrease as the required driving force increases. As the required driving force for the vehicle increases, the deceleration generated in the vehicle can be reduced. This makes it difficult for the driver to depress the accelerator pedal, and when the driver is sensitive to changes in vehicle speed, the driver is dragging the brake. It can prevent a sense of incongruity.

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 control 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.
In the present invention configured as described above, the driving force control means reduces the torque of the motor in accordance with the yaw rate related amount of the vehicle, so that the driving force of the vehicle can be reduced directly. Therefore, compared with the case where the drive force of the vehicle is reduced by controlling the hydraulic brake unit, the response of the drive force reduction can be improved, and the behavior of the vehicle can be controlled more directly.

In the present invention, it is preferable that the electrically driven vehicle further includes a battery state detection unit that detects a state of the battery, and a display unit that displays information related to control by the driving force control unit, and the driving force control. When it is determined that the battery cannot recover the regenerative power generated by the motor based on the state of the battery, the display unit displays information indicating that the driving force of the vehicle is not reduced and the driving force of the vehicle is not reduced. Display.
In the present invention configured as described above, the driving force control means may cause the battery to be overcharged when the regenerative electric power generated by the motor is recovered by the battery, or the battery temperature may exceed the allowable temperature range. Since the motor torque is not reduced and regenerative power is not generated, it is possible to prevent damage to the battery due to overcharge or deviation from the allowable temperature range. Further, since the driving force control means displays information indicating that the driving force of the vehicle is not reduced on the display means, it is possible to prevent the driver from feeling uncomfortable because the driving force is not reduced when entering the curve.

  According to the vehicle behavior control device of the present invention, the driver's operation at the time of cornering of the vehicle becomes natural and stable without causing the driver to feel uncomfortable feeling that the brake is dragged. The behavior can be controlled.

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 process in which the behavior control apparatus for vehicles by embodiment of this invention controls the behavior of a vehicle. 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. It is a map referred when the driving force control part by embodiment of this invention determines the correction coefficient of driving force reduction amount based on an accelerator opening. FIG. 6A is a diagram showing a time change of parameters related to behavior control by the vehicle behavior control device when a vehicle equipped with the vehicle behavior control device according to the embodiment of the present invention turns right. FIG. 6B is a plan view schematically showing a vehicle that makes a right turn. FIG. 6B is a diagram showing a change in the steering angle of the vehicle that makes a right turn as shown in FIG. ) Is a diagram showing a change in the target yaw rate calculated based on the steering angle of the vehicle shown in FIG. 6B, and FIG. 6D is a target calculated based on the target yaw rate shown in FIG. 6C. 6 is a diagram showing a change in yaw acceleration. FIG. 6E is a diagram showing a change in torque control amount of the motor determined by the driving force control unit based on the target yaw acceleration shown in FIG. 6D. FIG. 6 (e) shows a vehicle in which steering is performed as shown in FIG. 6 (b). The change of the yaw rate generated on the vehicle when performing the torque control of the motor as a diagram showing the change of the yaw rate generated on the vehicle when you did not torque control of the motor.

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, a vehicle 1 equipped with the vehicle behavior control apparatus according to the present embodiment is an electric vehicle or a hybrid vehicle in which a battery 2 (secondary battery) is mounted as a power source and the front wheels are steered. 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.

In addition, the vehicle 1 includes a steering angle sensor 12 that detects a rotation angle of the steering wheel 10, an accelerator opening sensor 14 that detects an accelerator opening, and a rotation angular velocity of the vehicle 1 around a vertical axis (yaw axis) ( A yaw rate sensor 16 for detecting (yaw rate). Each of these sensors outputs the detected value to the vehicle behavior control device 18.
Furthermore, the vehicle 1 has an indicator 20 that displays information related to behavior control of the vehicle 1 by the vehicle behavior control device 18.
Further, the battery 2 includes a battery state detection unit 22 that detects the SOC (State Of Charge) and temperature of the battery 2.

Next, the electrical configuration of the vehicle behavior control apparatus 18 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 18 according to the embodiment of the present invention.
The vehicle behavior control device 18 includes a yaw acceleration calculation unit 24 that calculates a target yaw acceleration of the vehicle 1 and a driving force control unit 26 that reduces the driving force of the vehicle 1 according to the target yaw acceleration of the vehicle 1.
The vehicle behavior control device 18 includes a steering angle detected by the steering angle sensor 12, an accelerator opening detected by the accelerator opening sensor 14, a yaw rate detected by the yaw rate sensor 16, and a battery detected by the battery state detection unit 22. 2 SOC and temperature are entered.

The yaw acceleration calculation unit 24 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, and calculates the target yaw acceleration of the vehicle 1 based on the target yaw rate.
The driving force control unit 26 determines a torque reduction amount (that is, driving force reduction amount) of the motor 6 based on the calculated target yaw acceleration, accelerator opening (that is, required driving force), and the state of the battery 2, and The amount of regenerative power generated by the motor 6 is controlled so that the torque reduction amount of the motor 6 is realized. The driving force control unit 26 outputs information indicating whether or not the driving force control unit 26 is in a state in which the driving force of the motor 6 can be controlled to the indicator 20.
The yaw acceleration calculation unit 24 and the driving force control unit 26 are a CPU, various programs interpreted and executed on the CPU (basic control programs such as an OS, and applications that are activated on the OS and realize specific functions. And a computer having an internal memory such as a ROM or RAM for storing the program and various data.

Next, processing performed by the vehicle behavior control device 18 will be described with reference to FIGS. 3 to 5.
FIG. 3 is a flowchart of a behavior control process in which the vehicle behavior control device 18 according to the embodiment of the present invention controls the behavior of the vehicle 1. This behavior control process is activated and executed repeatedly when the ignition of the vehicle 1 is turned on and the vehicle behavior control device 18 is powered on.

  As shown in FIG. 3, when the behavior control process is started, in step S <b> 1, the driving force control unit 26 acquires the steering angle detected by the steering angle sensor 12.

  Next, in step S2, the driving force control unit 26 determines whether or not the steering angle acquired in step S1 is greater than or equal to a predetermined threshold value. As a result, when the steering angle is not greater than or equal to the predetermined threshold (below the threshold), the vehicle behavior control device 18 does not need to control the behavior of the vehicle 1 because steering is not performed, and behavior control is performed. The process ends.

  On the other hand, when the steering angle is equal to or larger than the predetermined threshold value, the process proceeds to step S3, and the driving force control unit 26 determines whether or not the absolute value of the steering angle acquired in step S1 is increasing. As a result, if the absolute value of the steering angle is not increasing (constant or decreasing), the vehicle behavior control device 18 is holding or switching back the steering operation, not cutting, It is assumed that there is no need to control the behavior of the vehicle 1, and the behavior control process is terminated.

  On the other hand, when the absolute value of the steering angle is increasing, the process proceeds to step S <b> 4 and the driving force control unit 26 acquires the SOC and temperature of the battery 2 detected by the battery state detection unit 22.

  Next, in step S5, the driving force control unit 26 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 S4. The driving force control unit 26 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 S6, where the yaw acceleration calculation unit 24 determines the steering angle input from the steering angle sensor 12 and the vehicle speed of the vehicle 1. Based on this, the target yaw rate of the vehicle 1 is calculated, and the target yaw acceleration of the vehicle 1 is calculated based on this target yaw rate. Specifically, the yaw acceleration calculation unit 24 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 of the vehicle 1, and time-differentiates the target yaw rate. To calculate the target yaw acceleration.

Next, in step S7, the driving force control unit 26 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 24 in step S6. 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 account the accelerator opening and the regenerative electric energy that can be recovered by the battery 2. This is a basic value.
Specifically, the driving force control unit 26 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 24 in step S6. Specify torque.
FIG. 4 is a map that is referred to when the driving force control unit 26 according to the embodiment of the present invention determines the basic control intervention torque based on the target yaw acceleration. The horizontal axis in FIG. 4 represents the target yaw acceleration, and the vertical axis represents the basic control intervention torque. As shown in FIG. 4, 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 26 performs control so as 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 S <b> 8, the driving force control unit 26 acquires the accelerator opening detected by the accelerator opening sensor 14.

Next, in step S9, the driving force control unit 26 determines a correction coefficient K for correcting the basic control intervention torque based on the accelerator opening obtained in step S8.
Specifically, the driving force control unit 26 refers to a map showing the relationship between the accelerator opening and the correction coefficient K, and specifies the correction coefficient K corresponding to the accelerator opening acquired in step S8.
FIG. 5 is a map that is referred to when the driving force control unit 26 according to the embodiment of the present invention determines the correction coefficient for the torque reduction amount based on the accelerator opening. The horizontal axis in FIG. 5 represents the accelerator opening, and the vertical axis represents the correction coefficient K. As shown in FIG. 5, when the accelerator opening is less than 60%, the correction coefficient K is set to be smaller as the accelerator opening is larger. When the accelerator opening is 60% or more, the correction coefficient K is constant at a minimum value of 0.25. When the accelerator opening is 0%, the correction coefficient K is a maximum value of 1.

Next, in step S10, the driving force control unit 26 determines a control intervention acceptable torque based on the state of the battery 2 acquired in step S4. 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 26 specifies the amount of regenerative power 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 S11, the driving force control unit 26 determines a corrected control intervention torque obtained by correcting the basic control intervention torque determined by the driving force control unit 26 in step S7. Specifically, the driving force control unit 26 includes the torque value obtained by multiplying the basic control intervention torque determined in step S7 by the correction coefficient K determined in step S9, and the control intervention acceptable torque determined in step S10. The smaller one is determined as the correction control intervention torque.

  Next, in step S12, the driving force control unit 26 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 S11. Specifically, the driving force control unit 26 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 S11. As a result, the driving force control unit 26 decreases the driving force having a magnitude corresponding to the correction control intervention torque.

  In step S5, 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> 13, the driving force control unit 26 causes the indicator 20 to display information indicating that the vehicle behavior control device 18 cannot execute the control for reducing the driving force of the vehicle 1.

  After step S12 or S13, the vehicle behavior control device 18 ends the behavior control process.

  Next, the operation of the vehicle behavior control apparatus 18 according to the embodiment of the present invention will be described with reference to FIG. FIG. 6 is a diagram showing time changes in parameters related to behavior control by the vehicle behavior control device 18 when the vehicle 1 equipped with the vehicle behavior control device 18 according to the embodiment of the present invention makes a right turn. .

  FIG. 6A is a plan view schematically showing the vehicle 1 that performs a right turn. As shown in FIG. 6A, the vehicle 1 turns rightward from position A via position B to position C.

FIG. 6B is a diagram showing changes in the steering angle of the vehicle 1 that turns right as shown in FIG. In FIG. 6B, the horizontal axis indicates time, and the vertical axis indicates the steering angle (rightward is positive).
As shown in FIG. 6B, rightward steering is started at the position A, and the steering angle is gradually increased as the steering operation is performed. At the position B, the rightward steering angle is maximized. Become. Thereafter, when the steering switch-back operation is performed, the rightward steering angle gradually decreases, and the steering angle becomes zero at position C.

FIG. 6C is a diagram showing a change in the target yaw rate calculated based on the steering angle of the vehicle 1 shown in FIG. In FIG. 6C, the horizontal axis indicates time, and the vertical axis indicates the target yaw rate (clockwise (CW) is positive).
As shown in FIG. 6C, the target yaw rate of the vehicle 1 changes in proportion to the change in the steering angle. That is, when rightward steering is started at position A, a clockwise (CW) target yaw rate is calculated, and a clockwise target yaw rate is maximized at position B. Thereafter, the clockwise target yaw rate gradually decreases, and at position C, the target yaw rate becomes zero. However, since the steering switching operation is performed from the position B to the position C, the driving force control unit 26 determines in step S3 of the behavior control process described above that the absolute value of the steering angle is not increasing. The behavior control process is terminated. Therefore, from position B to position C, the driving force control unit 26 does not calculate the target yaw rate.

FIG. 6D is a diagram showing a change in the target yaw acceleration calculated based on the target yaw rate shown in FIG. In FIG. 6D, the horizontal axis indicates time, and the vertical axis indicates target yaw acceleration (clockwise (CW) is positive).
The target yaw acceleration of the vehicle 1 is expressed by time differentiation of the target yaw rate of the vehicle 1. That is, as shown in FIG. 6D, when the rightward steering is started at the position A and the clockwise target yaw rate is calculated, the clockwise (CW) target yaw acceleration is calculated. The target yaw acceleration in the clockwise direction becomes maximum with respect to B. Thereafter, the clockwise target yaw acceleration decreases, and when the clockwise target yaw rate becomes maximum at the position B, the target yaw acceleration becomes zero. Further, when the clockwise target yaw rate decreases from position B to position C, the counterclockwise (CCW) target yaw acceleration is calculated, and the counterclockwise target yaw acceleration between position B and position C becomes maximum. After that, at the position C, the target yaw acceleration becomes zero. However, since the steering switchback operation is performed from position B to position C, in step S3 of the behavior control process described above, the driving force control unit 26 determines that the absolute value of the steering angle is not increasing. Then, the behavior control process ends. Therefore, from position B to position C, the driving force control unit 26 does not calculate the target yaw acceleration.

FIG. 6E is a diagram showing a change in the torque control amount of the motor 6 determined by the driving force control unit 26 based on the target yaw acceleration shown in FIG. In FIG. 6E, the horizontal axis indicates time, and the vertical axis indicates the torque control amount (torque increase is positive).
FIG. 6E shows that the correction control intervention torque determined by the driving force control unit 26 in step S11 of the behavior control process described above is the basic control intervention torque determined in step S7 by using the correction coefficient K determined in step S9. This shows a case where the torque value is multiplied (that is, a case where the torque value obtained by multiplying the basic control intervention torque by the correction coefficient K is smaller than the control intervention acceptable torque).
As described above, the driving force control unit 26 performs control so that the basic control intervention torque is increased and the increase rate of the increase amount is decreased as the target yaw acceleration increases. Therefore, as shown in FIG. 6 (e), when the clockwise target yaw acceleration is calculated at the position A, the torque reduction amount increases as the target yaw acceleration increases, and the position between the position A and the position B is increased. When the clockwise target yaw acceleration becomes maximum, the torque reduction amount also becomes maximum. Thereafter, the torque reduction amount decreases as the clockwise target yaw acceleration decreases, and when the target yaw acceleration becomes zero at position B, the torque reduction amount also becomes zero. Since the steering switchback operation is performed from position B to position C, in step S3 of the behavior control process described above, the driving force control unit 26 determines that the absolute value of the steering angle is not increasing, End the behavior control process. Therefore, from position B to position C, the driving force control unit 26 does not perform torque reduction (ie, torque reduction amount = 0).
The driving force control unit 26 determines the correction control intervention torque by multiplying the basic control intervention torque determined in step S7 by the correction coefficient K determined in step S9 of the behavior control process described above, and the correction control intervention torque. The driving force of a size corresponding to is reduced. As described above, the correction coefficient K is set so as to decrease as the accelerator opening increases. Therefore, as the accelerator opening increases, the correction control intervention torque decreases, and the torque reduction amount decreases as shown in FIG.

FIG. 6 (f) occurs in the vehicle 1 when the torque control of the motor 6 is performed as shown in FIG. 6 (e) in the vehicle 1 that is steered as shown in FIG. 6 (b). It is a diagram which shows the change of a yaw rate (actual yaw rate), and the change of an actual yaw rate when the torque control of the motor 6 is not performed. In FIG. 6F, the horizontal axis indicates time, and the vertical axis indicates yaw rate (clockwise (CW) is positive). Further, a solid line in FIG. 6F indicates a change in the actual yaw rate when the torque control of the motor 6 is performed, and a broken line indicates a change in the actual yaw rate when the torque control of the motor 6 is not performed.
When the rightward steering is started at the position A and the torque reduction amount increases as shown in FIG. 6E as the clockwise target yaw acceleration increases, the load on the front wheels, which are the steering wheels of the vehicle 1, increases. . As a result, the frictional force between the front wheels and the road surface increases, and the cornering force of the front wheels increases, so that the turning ability of the vehicle 1 is improved. That is, as shown in FIG. 6 (f), the vehicle 1 is more subject to the torque control of the motor 6 than the case where the torque control of the motor 6 is not performed between the position A and the position B. The generated clockwise yaw rate is increased. Further, as shown in FIG. 6E, the torque reduction amount decreases as the accelerator opening increases, so that the actual yaw rate and torque when the torque control of the motor 6 is not performed increases as the accelerator opening increases. The difference from the actual yaw rate when the control is performed is reduced.

Next, further modifications of the embodiment of the present invention will be described.
In the above-described embodiment, it has been described that the vehicle 1 equipped with the vehicle behavior control device 18 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 the power source. The device 18 may be mounted. In this case, the driving force control unit 26 controls the fuel injection amount and the transmission according to the yaw acceleration to reduce the driving force by the gasoline engine or the diesel engine.

In the above-described embodiment, the driving force control unit 26 has been described to determine the torque reduction amount of the motor 6 based on the target yaw acceleration and the accelerator opening calculated by the yaw acceleration calculation unit 24. The torque reduction amount of the motor 6 may be determined based on other parameters related to the yaw rate.
For example, the yaw acceleration calculation unit 24 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 26 calculates the yaw acceleration and accelerator opening calculated in this way. Based on the above, the torque reduction amount of the motor 6 may be determined. In this case, the driving force control unit 26 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. Correction is made so that the torque reduction amount decreases as the accelerator opening of 1 increases.
Alternatively, the lateral acceleration generated as the vehicle 1 turns is detected by an acceleration sensor mounted on the vehicle 1, and the driving force control unit 26 determines the torque reduction amount of the motor 6 based on the lateral acceleration. May be. In this case, the driving force control unit 26 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. Correction is made so that the torque reduction amount decreases as the accelerator opening of 1 increases.

  Further, in the above-described embodiment, in the map shown in FIG. 5, when the accelerator opening is 60% or more, the case where the correction coefficient K is constant at the minimum value 0.25 is exemplified. Even when the accelerator opening is 60% or more, the correction coefficient K may be decreased as the accelerator opening increases (minimum value 0).

  Next, effects of the vehicle behavior control device 18 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 26 of the vehicle behavior control device 18 increases the torque reduction amount of the motor 6 of the vehicle 1 and decreases the increase rate of the increase amount as the target yaw acceleration of the vehicle 1 increases. To control. That is, when the steering of the vehicle 1 is started and the target yaw acceleration of the vehicle 1 starts to increase, the driving force control unit 26 quickly increases the torque reduction amount of the motor 6, so that the deceleration at the start of the steering of the vehicle 1 is performed. Can be quickly generated in the vehicle 1 and a sufficient load can be quickly applied to the front wheels as the steering wheels. As a result, the frictional force between the front wheels, which are the steered wheels, and the road surface increases, and the cornering force of the front wheels increases, so that the turning ability of the vehicle 1 at the initial stage of the curve approach can be improved, and the steering turning operation can be prevented. Responsiveness can be improved. Further, since the driving force control unit 26 decreases the rate of increase in the torque reduction amount of the vehicle 1 as the target yaw acceleration increases, the deceleration generated in the vehicle 1 during curve traveling does not become excessive, and the steering ends. Sometimes the deceleration can be reduced quickly. Therefore, it is possible to prevent the driver from feeling a drag of reducing the driving force when exiting the curve. Furthermore, since the driving force control unit 26 corrects the determined torque reduction amount to decrease as the accelerator opening of the vehicle 1 increases, the deceleration generated in the vehicle 1 decreases as the required driving force for the vehicle increases. Thus, it is possible to prevent the driver from feeling uncomfortable as if the driver is depressing the accelerator pedal and is sensitive to changes in the vehicle speed, such as dragging the brake. As described above, according to the vehicle behavior control device 18, the behavior of the vehicle 1 is controlled so that the operation of the driver at the cornering of the vehicle 1 becomes natural and stable without causing the driver to feel uncomfortable. Can do.

  Further, when the accelerator opening is equal to or greater than a predetermined value (60%), the driving force control unit 26 causes the vehicle 1 to generate a minimum deceleration according to the target yaw acceleration of the vehicle 1 or to set the deceleration. When the accelerator opening is less than the predetermined value (60%) without being generated, the deceleration generated in the vehicle 1 increases as the required driving force decreases, so the driver depresses the accelerator pedal greatly, and the vehicle speed changes When the driver is not sensitive to changes in vehicle speed and the driver does not depress the accelerator pedal too much, the amount of depression of the accelerator pedal can be reduced. The smaller it is, the better the response to the steering operation.

  In addition, the driving force control unit 26 performs control to reduce the torque of the motor 6 of the vehicle 1 when the absolute value of the steering angle of the vehicle 1 is increasing. That is, when the absolute value of the steering angle of the vehicle 1 is increased due to the steering turning operation, the torque of the motor 6 is reduced. It is possible to increase the cornering force of the front wheels by applying a load to the front wheels, which are the steering wheels, and to reliably improve the responsiveness of the vehicle 1 to the steering turning operation.

  The driving force control unit 26 corrects the torque reduction amount determined by the driving force control unit 26 to decrease as the accelerator opening of the vehicle 1 increases. Therefore, the driving force control unit 26 reduces the amount of reduction generated in the vehicle 1 as the accelerator opening increases. The speed can be reduced, thereby preventing the driver from feeling uncomfortable as if the driver is dragging the brake when the driver has depressed the accelerator pedal greatly and is sensitive to changes in the vehicle speed.

  In particular, 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, and includes a driving force control unit 26. 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, since the driving force control unit 26 reduces the torque of the motor 6 according to the target yaw acceleration of the vehicle 1, the driving force of the vehicle 1 can be reduced directly. Therefore, compared with the case where the driving force of the vehicle 1 is reduced by controlling the hydraulic brake unit, the response of the driving force reduction can be improved, and the behavior of the vehicle 1 can be controlled more directly.

  Furthermore, when it is determined that the battery 2 cannot recover the regenerative power generated by the motor 6 based on the state of the battery 2, the driving force control unit 26 does not reduce the driving force of the vehicle 1 and drives the vehicle 1. Information indicating that the force is not reduced is displayed on the indicator 20. That is, when the battery 2 is overcharged when the regenerative power generated by the motor 6 is collected by the battery 2 or when the temperature of the battery 2 exceeds the allowable temperature range, the driving force control unit 26 Since the torque is not reduced and regenerative power is not generated, the battery 2 can be prevented from being damaged. Further, since the driving force control unit 26 displays information indicating that the driving force of the vehicle 1 is not reduced on the indicator 20, it is possible to prevent the driver from feeling uncomfortable because the driving force is not reduced when entering the curve.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Battery 4 Driving wheel 6 Motor 8 Inverter 10 Steering wheel 12 Steering angle sensor 14 Accelerator opening sensor 16 Yaw rate sensor 18 Vehicle behavior control device 20 Indicator 22 Battery state detection part 24 Yaw acceleration calculation part 26 Driving force control part

Claims (6)

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;
Driving force control means for controlling to reduce the driving force of the vehicle according to the yaw rate related quantity acquired by the yaw rate related quantity acquisition means,
The driving force control means determines the driving force reduction amount so as to increase the driving force reduction amount of the vehicle and reduce the increase rate of the increasing amount as the yaw rate related amount increases. And a driving force reduction amount correction unit that corrects the driving force reduction amount determined by the driving force reduction amount determination unit as the required driving force for the vehicle increases. Vehicle behavior control device.   The driving force reduction amount correcting unit corrects the driving force reduction amount determined by the driving force reduction amount determining unit to decrease as the required driving force increases when the required driving force is less than a predetermined value. 2. The vehicle behavior control device according to claim 1, wherein when the required driving force is equal to or greater than a predetermined value, the driving force reduction amount determined by the driving force reduction amount determining means is corrected to a certain minimum value. .   The vehicle behavior control device according to claim 1 or 2, wherein the driving force control means performs control to reduce the driving force of the vehicle when the absolute value of the steering angle of the vehicle is increased.   The driving force reduction amount correction means multiplies the driving force reduction amount determined by the driving force reduction amount determination means by a coefficient set so as to decrease as the required driving force increases, thereby reducing the driving force reduction. The vehicle behavior control device according to any one of claims 1 to 3, wherein the amount is corrected. 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,
5. The driving force control unit according to claim 1, wherein the driving force of the vehicle is reduced by controlling a regenerative electric power generated by the motor according to the yaw rate related amount. 6. Vehicle behavior control device. The electrically driven vehicle further includes battery state detection means for detecting the state of the battery, and display means for displaying information related to control by the driving force control means,
The driving force control means does not reduce the driving force of the vehicle and reduces the driving force of the vehicle when it is determined that the battery cannot recover the regenerative power generated by the motor based on the state of the battery. 6. The vehicle behavior control device according to claim 5, wherein information indicating that no reduction is to be performed is displayed on the display means.

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