JP2011240740A - Braking control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a braking control device of a vehicle capable of efficiently cooperating between regenerative braking and frictional braking, in vehicle stabilizing control for securing stability of the vehicle.SOLUTION: This braking control device includes: a frictional braking unit FRC for imparting frictional braking torque to a wheel of the vehicle; a regenerative braking unit RGN for imparting regenerative braking torque to the wheel; and a control unit CTL. The control unit CTL executes frictional braking control for increasing the frictional braking torque based on a first state quantity Tcx (for example, a steering characteristic quantity Sch) arithmetically operated based on a turning quantity Tca indicating a degree of a turning state of the vehicle, and executes regenerative braking control for increasing the regenerative braking torque based on a second state quantity Tcy (for example, a steering speed dSa) different from the first state quantity Tcx arithmetically operated based on the turning quantity Tca. The control unit CTL starts an increase in the frictional braking torque after starting an increase in the regenerative braking torque. The regenerative braking unit RGN is provided in at least a front wheel among wheels.

Description

  The present invention relates to a vehicle braking control device that ensures the stability of a vehicle by cooperating regenerative braking and friction braking.

  Patent Document 1 states that “in a vehicle having two brakes, a hydraulic brake and a regenerative brake, when the antilock control is started by the hydraulic brake for the purpose of improving the controllability of the antilock control. The control is performed so that the regenerative braking force becomes zero. " That is, when braking control is performed independently of the driver's braking operation, interference between the hydraulic brake (friction braking using the brake fluid pressure) and the regenerative brake (regenerative braking using the drive motor) is avoided. Therefore, the braking control is executed by stopping the operation of the regenerative braking and operating only the friction braking.

JP-A-6-171490

  Since regenerative braking has high responsiveness to friction braking and energy regeneration can be expected, a braking control device capable of cooperating regenerative braking and friction braking is desired. An object of the present invention is to provide a vehicle braking control device capable of efficiently cooperating regenerative braking and friction braking in vehicle stabilization control for ensuring vehicle stability.

  A vehicle braking control apparatus according to the present invention includes a friction braking unit (FRC), a regenerative braking unit (RGN), a turning amount acquisition unit (TCA), a first calculation unit (TCX), a second calculation unit (TCY), and And control means (CTL). The friction braking means (FRC) applies friction braking torque (Pwt [**], Pwa [**]) to the vehicle wheel (WH [**]). The regenerative braking means (RGN) applies a regenerative braking torque (Qwt [**], Qwa [**]) to the wheel (WH [**]). The turning amount acquisition means (TCA) acquires a turning amount (Tca) representing the degree of turning state of the vehicle. The first calculation means (TCX) calculates a first state quantity (Tcx) based on the turning amount (Tca). The second calculating means (TCY) calculates a second state quantity (Tcy) different from the first state quantity (Tcx) based on the turning amount (Tca). The control means (CTL) controls the friction braking torque (Pwt [**], Pwa [**]) based on the first state quantity (Tcx) independently of the braking operation of the driver of the vehicle. Increase friction braking control is executed. In addition, the control means (CTL) is configured to generate the regenerative braking torque (Qwt [**], Qwa [**) based on the second state quantity (Tcy) independently of the braking operation of the driver of the vehicle. ]) To increase the regenerative braking control.

  The control means (CTL) starts increasing the regenerative braking torque (Qwt [**], Qwa [**]) and then increases the friction braking torque (Pwt [**], Pwa [**]). Configured to start increasing. Further, the regenerative braking means (RGN) may be configured to be provided on at least the front wheel (WH [f *]) among the wheels.

  In the vehicle braking control apparatus according to the present invention, the turning amount obtaining means (TCA) is operated by the vehicle yaw rate (Yra) and the vehicle driver as the turning amount (Tca). The steering amount (Saa) of the operation member (SW) is acquired. The first computing means (TCX) is a steering characteristic amount representing a degree of the steering characteristic of the vehicle based on the yaw rate (Yra) and the steering amount (Saa) as the first state quantity (Tcx). (Sch) is calculated. The second calculating means (TCY) is configured to calculate a steering speed (dSa) of the steering operation member (SW) based on the steering amount (Saa) as the second state quantity (Tcy). Is done.

  The vehicle braking control apparatus according to the present invention includes third calculation means (TCZ), and based on the turning amount (Tca), the first state quantity (Tcx) and the second state quantity (Tcy) Computes a different third state quantity (Tcz). The control means (CTL) increases the regenerative braking torque (Qwt [**], Qwa [**]) when the third state quantity (Tcz) exceeds a reference value (Stc, Trf). Configured. Further, the control means (CTL) determines a transient steering state in which the steering amount (Saa) continuously increases or decreases based on the steering amount (Saa). The control means (CTL) may be configured to change the reference value (Stc, Trf) to a smaller value (stc2, Trf2) when determining the transient steering state.

  Specifically, the control means (CTL) determines whether the steering direction of the vehicle is one direction or the other direction based on the steering amount (Saa), and is the one direction. The transient steering state is determined when it is determined that the direction is the other direction continuously after being determined. The control means (CTL) may determine the transient steering state when the steering amount (Saa) continuously decreases after increasing.

  In the vehicle braking control apparatus according to the present invention, it is desirable that the control means (CTL) sets the reference value (Trf) based on the steering speed (dSa). Specifically, the reference value (Trf) is determined to be smaller as the steering speed (dSa) is larger, or is determined to be larger as the steering speed (dSa) is smaller.

  The vehicle braking control apparatus according to the present invention includes storage means (DSAP) and stores a peak value (dSap) of the steering speed based on the steering speed (dSa). The control means (CTL) may be configured to set the reference value (Trf) based on a peak value (dSap) of the steering speed. Further, the turning amount acquisition means (TCA) acquires at least one of the yaw rate (Yra) of the vehicle and the lateral acceleration (Gya) of the vehicle as the turning amount (Tca), and the control The means (CTL) calculates a lateral acceleration equivalent amount (Gya, Gye) corresponding to the lateral acceleration of the vehicle based on the acquisition result of the turning amount acquisition means (TCA) as the third state quantity (Tcz). Can be configured as follows.

  The vehicle braking control apparatus according to the present invention includes a braking operation amount acquisition means (BSA), and acquires a braking operation amount (Bsa) of a braking operation member (BP) operated by a driver of the vehicle. The control means (CTL) increases the regenerative braking torque (Qwt [**], Qwa [**]) when the braking operation amount (Bsa) is equal to or less than a predetermined operation amount (predetermined value bsa1). When the braking operation amount (Bsa) is larger than the predetermined operation amount (bsa1), the regenerative braking torque (Qwt [**], Qwa [**]) is held. The predetermined operation amount (bsa1) is preferably a value (bsa1 = 0) corresponding to a state in which the braking operation member (BP) is not operated by the driver of the vehicle.

  Since this invention is comprised as mentioned above, there exist the following effects.

  Since regenerative braking torque by regenerative braking control and friction braking torque by friction braking control are adjusted (increased) based on different state quantities (first state quantity and second state quantity), regenerative braking and friction braking are performed. Control interference can be avoided and these can be coordinated to improve vehicle stability. Since the generation of regenerative braking torque is more responsive than the generation of friction braking torque, first, vehicle stability is ensured by the regenerative braking torque. If the braking torque is still insufficient, the friction braking is continued. Torque is generated. Thereby, vehicle stability can be ensured efficiently. Further, a larger braking torque is required earlier when the oversteer tendency is eliminated than when the understeer tendency is eliminated. Accordingly, at least the front wheels are provided with regenerative braking means, and the regenerative braking torque is applied to the front wheels, so that the oversteer tendency can be efficiently suppressed.

  Since the highly responsive regenerative braking torque is increased based on the steering speed, which is an early signal, vehicle stability can be secured quickly. Furthermore, since the friction braking torque that can generate a larger braking torque is increased based on the steering characteristic amount, the vehicle stability can be reliably maintained.

  The degree to which vehicle stability can be ensured differs depending on the steering state (whether or not it is a transient steering state). A transient steering state is discriminated, and a control execution threshold value (reference value) is set according to the discrimination result. Since the start of the regenerative braking torque increase is determined by comparing the third state quantity (for example, lateral acceleration) and the threshold value, the braking control according to the steering state can be performed.

  When the road surface friction coefficient is low, a sudden turning motion may not occur even if a sudden steering is performed. By setting a reference value (reference amount Trf) corresponding to the third state quantity according to the steering speed dSa, braking control according to the road surface condition can be performed. Although there is a phase difference between the steering operation and the turning behavior generated as a result of the steering operation, the reference value (reference amount Trf) is determined based on the peak value dSap of the steering speed. The phase difference is compensated, and reliable vehicle stabilization control can be executed. Since the influence of the road surface condition (road surface friction coefficient) is reflected in the lateral acceleration equivalent amount, the third state quantity is set to a value corresponding to the lateral acceleration, so that the braking control according to the road surface state is performed. obtain.

  When the driver is performing a braking operation, the braking torque has already been applied to the wheels, so regenerative braking control is not so necessary. Only when the braking operation amount is equal to or less than the predetermined operation amount (predetermined value bsa1), the regenerative braking torque is increased. Particularly, when the braking operation by the driver is not performed, the effect of increasing the regenerative braking torque is great.

1 is a diagram illustrating an overall configuration of a vehicle including a vehicle braking control device according to an embodiment of the present invention. It is a figure explaining steering operation in the case of avoiding an obstacle urgently. It is a functional block diagram which shows the example of a calculation process of the braking control apparatus of the vehicle in this embodiment. It is a functional block diagram for demonstrating the 1st example of a calculation process in the regenerative torque control calculation block RTC. It is a functional block diagram for demonstrating the 2nd calculation processing example in the regenerative torque control calculation block RTC. It is a control flowchart for demonstrating the example of a calculation process in the regeneration control execution determination part of the target regeneration torque calculation block QWT. It is a time-series diagram for demonstrating the effect | action and effect of the braking control apparatus of the vehicle which concerns on embodiment of this invention.

  FIG. 1 is a diagram illustrating an overall configuration of a vehicle including a vehicle braking control device according to an embodiment of the present invention. The subscript [**] attached to the end of various symbols indicates whether the various symbols are related to any of the four wheels. “F” is the front wheel, “r” is the rear wheel, “m” is the right wheel with respect to the vehicle traveling direction, “h” is the left wheel, “o” is the outer wheel (outer wheel) with respect to the turning direction, “i” "Indicates an inner wheel (inner ring). Therefore, “fh” indicates the left front wheel, “fm” indicates the right front wheel, “rh” indicates the left rear wheel, and “rm” indicates the right rear wheel. “Fo” is the outer front wheel (outer front wheel), “fi” is the inner front wheel (inner front wheel), “ro” is the outer rear wheel (outer rear wheel), and “ri” is the inner rear wheel (inner). Rear wheel).

  Further, the turning direction of the vehicle may be rightward or leftward. They are generally given positive and negative signs, for example, the left direction is represented as a positive sign and the right direction is represented as a negative sign. Further, the acceleration / deceleration of the vehicle is generally given a positive / negative sign, for example, acceleration is expressed as a positive sign and deceleration is expressed as a negative sign. However, when describing the magnitude relationship of the values or the increase / decrease in the values, it becomes very complicated when the sign is taken into account. Therefore, unless there is a particular limitation, the absolute value magnitude relationship and the absolute value increase / decrease are represented. The predetermined value is a positive value set in advance.

  The vehicle includes a wheel speed sensor WS [**] that detects the wheel speed Vwa [**], and a rotation angle θsw of the steering wheel SW (from a neutral position “0” of the steering device that corresponds to the vehicle traveling straight). Steering wheel angle sensor SA for detecting steering angle, front wheel steering angle sensor FS for detecting steering angle δfa of the steered wheel (front wheel), and steering torque sensor ST for detecting torque Tsw when the driver operates the steering wheel SW A yaw rate sensor YR that detects an actual yaw rate Yra acting on the vehicle, a longitudinal acceleration sensor GX that detects a longitudinal acceleration Gxa in the longitudinal direction of the vehicle body, a lateral acceleration sensor GY that detects a lateral acceleration Gya in the lateral direction of the vehicle body, A wheel cylinder pressure sensor PW [**] that detects the brake fluid pressure Pwa [**] of the wheel cylinder WC [**], and a rotation of the engine EG An engine rotational speed sensor NE for detecting the speed Nea, throttle position sensor TS is provided for detecting the opening Tsa of the throttle valve of the engine.

  As means for detecting the driver's driving operation, an acceleration operation amount sensor AS for detecting the operation amount Asa of the driver's acceleration operation member (for example, accelerator pedal) AP, and the driver's braking operation member (for example, brake) Pedal) A braking operation amount sensor BS for detecting the operation amount Bsa of the BP and a shift position sensor HS for detecting the shift position Hsa of the speed change operation member SF are provided.

  The vehicle also includes a brake actuator BRK that controls the brake fluid pressure, a throttle actuator TH that controls the throttle valve, a fuel injection actuator FI that controls fuel injection, and an automatic transmission AT that controls the shift. It has been. Further, the vehicle is provided with electric motors MT for driving on the front wheels and the rear wheels. The drive motor MT also functions as a regenerative braking device RGN that generates regenerative braking torque on each wheel. The drive electric motor MT (RGN) is provided at least on the front wheels, and the drive electric motor MT (RGN) on the rear wheels may be omitted. In the present embodiment, a hybrid configuration including the electric motor MT and the engine EG is shown, but the configuration may be an electric vehicle in which the engine EG and the automatic transmission AT are omitted.

  In addition, the vehicle includes an electronic control unit ECU that is electrically connected to the above-described various actuators (such as BRK) and the above-described various sensors (such as WS [**]). The electronic control unit ECU is a microcomputer composed of a plurality of independent electronic control units ECU (ECUb, ECUs, ECUe, ECUa) connected to each other via a communication bus CB. Each system electronic control unit (ECUb, etc.) in the electronic control unit ECU executes a dedicated control program. Signals (sensor values) of various sensors and signals (internally calculated values) calculated in each electronic control unit (ECUb or the like) are shared via the communication bus CB.

  The arithmetic processing of this apparatus is provided in the electronic control unit ECU. For example, the arithmetic processing of this device is programmed in the brake system electronic control unit ECUb that controls the brake actuator BRK. In the brake system electronic control unit ECUb, anti-skid control (ABS control) and the like are executed based on signals from the wheel speed sensor WS [**], the yaw rate sensor YR, the lateral acceleration sensor GY, and the like. Further, based on the wheel speed Vwa [**] of each wheel detected by the wheel speed sensor WS [**], the traveling speed (vehicle speed) Vxa of the vehicle is calculated by a known method.

  In the steering system electronic control unit ECUs, electric power steering control (EPS control) is executed based on a signal from the steering torque sensor ST or the like. In the engine system electronic control unit ECUe, the throttle actuator TH and the fuel injection actuator FI are controlled based on the signal Asa from the acceleration operation amount sensor AS and the like. In the drive motor electronic control unit ECUm, control of the drive electric motor MT is executed. The drive motor electronic control unit ECUm not only controls the wheel drive torque, but also controls the wheel regenerative braking torque in response to a request value (target value) of the regenerative braking torque from the brake system electronic control unit ECUb.

  The brake actuator BRK (corresponding to a part of the friction braking means FRC) has a well-known configuration including a plurality of electromagnetic valves (hydraulic pressure adjusting valves), a hydraulic pump, an electric motor, and the like. When executing the brake control, the brake actuator BRK can control the brake hydraulic pressure for each wheel cylinder WC [**] independently of the operation of the brake pedal BP, and can adjust the friction brake torque for each wheel.

  Each wheel is provided with a well-known wheel cylinder WC [**], brake caliper BC [**], brake pad PD [**], and brake rotor RT [**] as friction braking means FRC. When brake fluid pressure is applied to the wheel cylinder WC [**] provided in the brake caliper BC [**], the brake pad PD [**] is pressed against the brake rotor RT [**], and the friction force Thus, friction braking torque is applied to each wheel. The control of the friction braking torque is not limited to the braking hydraulic pressure, and can be performed using an electric brake device.

  At least the front wheel is provided with a drive electric motor MT as regenerative braking means RGN. In this embodiment, the drive electric motor MT is configured to apply regenerative braking torque to both front wheels and both rear wheels. The regenerative braking torque of the left and right wheels can be controlled independently. The drive electric motor MT for the rear wheel WH [r *] can be omitted.

  First, with reference to FIG. 2, a steering operation when an obstacle is urgently avoided will be described.

  FIG. 2A is referred to as J-turn steering, and is a case where an abrupt steering wheel operation is performed in one direction (that is, one of the left direction and the right direction). The steering operation by the driver is started at time p0, and the steering amount Saa (steering angle, steering wheel angle θsw or steering wheel rudder angle δfa) is “0 (steering neutral position until time p2; Corresponding to the vehicle's straight travel) ", and then reaches a steady value. At this time, the steering speed dSa (the steering angular speed, the time differential value of the steering amount) rises from “0” at time p0, reaches the maximum value (peak value) dSap at time p1, and becomes “0” at time p2. Return to.

  In J-turn steering, there is a low possibility that the stability of the vehicle in yawing motion (called yawing stability) will be impaired. However, when the road surface friction coefficient is high, the stability of the vehicle (referred to as rolling stability) in rolling motion may decrease.

  FIG. 2B is called lane change steering, and is continuously performed after a steering wheel operation is suddenly performed in one direction (that is, one of the left direction and the right direction, for example, the left steering direction). In this case, the steering wheel operation is performed in the other direction opposite to the one direction (that is, the other of the left direction and the right direction, for example, the right steering direction). At time q0, the steering operation by the driver is started in one direction (one steering direction). The steering amount (steering angle) Saa is increased from “0 (neutral position of steering, corresponding to straight traveling of the vehicle)” to one steering direction until time q1, and toward “0” after time q1. Returned. Further, the steering operation is started in the other direction (other steering direction) continuously at time q2. The steering amount Saa is increased from “0” to the other steering direction from time q2 to time q3, is returned toward “0” after time q3, and becomes “0” again at time q4. Here, an operation that is steered in one direction first is referred to as “first steering”, and an operation that is steered in the other direction continuously after this “first steering” is referred to as “second steering”. A continuous steering operation when the first steering and the second steering are performed is referred to as “transient steering”. Further, when the steering amount Saa moves away from “0 (steering neutral position)” (when the magnitude (absolute value) of the steering amount Saa increases), the steering amount Saa is “0 (steering). The case of approaching the “neutral position” (when the magnitude (absolute value) of the steering amount Saa decreases) is referred to as “returning” steering.

  In transient steering (for example, lane change steering) in which the steering amount continuously increases / decreases, when the first steering is switched back (from time q1 to time q2), or when the second steering is switched back (from time q2 to time) When the steering speed dSa in q3) is large, the yawing stability is likely to be impaired. This tendency is particularly noticeable when the road surface friction coefficient is low. That is, in low road surface friction, yawing stability may be impaired even when the steering speed dSa is relatively small. On the other hand, after the first steering is performed as shown by the broken line in FIG. 2B, the first steering is switched back relatively slowly and the second steering is not performed (that is, the transient steering is performed). If it is not performed), even if the sudden steering is performed when the first steering is increased, the possibility that the yawing stability is lowered is low.

  FIG. 3 is a functional block diagram illustrating a calculation processing example of the vehicle braking control device according to the present embodiment. The subscript [**] attached to the end of various symbols indicates whether the various symbols are related to any of the four wheels. “F” is the front wheel, “r” is the rear wheel, “m” is the right wheel with respect to the vehicle traveling direction, “h” is the left wheel, “o” is the outer wheel (outer wheel) with respect to the turning direction, “i” "Indicates an inner wheel (inner ring). Therefore, “fh” indicates the left front wheel, “fm” indicates the right front wheel, “rh” indicates the left rear wheel, and “rm” indicates the right rear wheel. “Fo” is the outer front wheel (outer front wheel), “fi” is the inner front wheel (inner front wheel), “ro” is the outer rear wheel (outer rear wheel), and “ri” is the inner rear wheel (inner). Rear wheel). Further, the turning direction of the vehicle may be rightward or leftward. They are generally given positive and negative signs, for example, the left direction is represented as a positive sign and the right direction is represented as a negative sign. Further, the acceleration / deceleration of the vehicle is generally given a positive / negative sign, for example, acceleration is expressed as a positive sign and deceleration is expressed as a negative sign. However, when describing the magnitude relationship of the values or the increase / decrease in the values, it becomes very complicated when the sign is taken into account. Therefore, unless there is a particular limitation, it represents the magnitude relationship between the absolute values and increases / decreases in the absolute values, and the predetermined value is a positive value. Further, the braking control for increasing the friction braking torque by FRC is called friction braking control, and the braking control for increasing the regenerative braking torque by regenerative braking means RGN is called regenerative braking control.

  In a turning amount acquisition calculation block (corresponding to a turning amount acquisition means) TCA, a turning amount Tca that is a state amount indicating the degree (size) of the turning state of the vehicle is acquired. The turning amount acquisition calculation block TCA includes a steering amount acquisition calculation block SAA, a yaw rate acquisition calculation block YRA, and a lateral acceleration acquisition calculation block GYA.

  In the steering amount acquisition calculation block (corresponding to the steering amount acquisition means) SAA, the steering amount (for example, steering angle) Saa of the steering operation member SW operated by the driver of the vehicle is acquired as the turning amount Tca. Specifically, the steering amount Saa is calculated based on a signal (steering wheel angle θsw which is the rotation angle of the steering wheel SW) detected by the steering wheel angle sensor SA. Further, it can be calculated based on the front wheel steering angle δfa detected by the front wheel steering angle sensor FS. That is, the steering amount (steering angle) Saa can be calculated based on at least one of the steering wheel angle θsw and the front wheel steering angle δfa.

  In the yaw rate acquisition calculation block YRA, the yaw rate Yra is acquired as the turning amount Tca. Specifically, the yaw rate Yra is calculated based on a signal detected by the yaw rate sensor YR. Further, the yaw rate Yra can be calculated based on the speed difference between the left and right wheels calculated from the wheel speed Vwa [**] that is the rotational speed of each wheel.

  In the lateral acceleration acquisition calculation block GYA, the lateral acceleration Gya is acquired as the turning amount Tca. Specifically, the lateral acceleration Gya is calculated based on a signal detected by the lateral acceleration sensor GY.

  The vehicle speed Vxa is calculated in the vehicle speed acquisition calculation block VXA. The vehicle speed Vxa can be calculated based on the wheel speed Vwa [**]. The wheel speed Vwa [**] is acquired by a wheel speed acquisition unit VWA (for example, a wheel speed sensor WS [**]).

  In a braking operation amount acquisition calculation block (corresponding to a braking operation amount acquisition means) BSA, an operation amount Bsa of a braking operation member (for example, a brake pedal) BP of the vehicle operated by the driver is acquired.

  In the first calculation block (corresponding to the first calculation means) TCX, the first state quantity Tcx is calculated. As the first state quantity Tcx, a state quantity (referred to as a steer characteristic quantity) Sch representing the degree (magnitude) of the steering characteristic of the vehicle is calculated. The steer characteristic amount Sch is a value representing the level of the understeer, neutral steer, and oversteer steer characteristics (understeer level or oversteer level) of the vehicle. The steer characteristic amount Sch is based on a comparison result (for example, yawing amount deviation ΔJr = Jra−Jrt) between a target vehicle yawing amount (target yawing amount Jrt) and an actual yawing amount (actual yawing amount Jra). Is calculated. Here, when ΔJr <0, understeer, when ΔJr = 0, it represents neutral steer, and when ΔJr> 0, it represents oversteer.

  The yawing amount is a state amount that represents the degree (magnitude) of the yawing motion of the vehicle, and includes yaw rate Yra, vehicle side skid angle (also simply referred to as side slip angle) βa, vehicle side skid angular velocity (also simply referred to as side slip angular velocity) dβa. It is a value calculated using at least one. For example, as the target yawing amount Jrt, the target yaw rate Yrt is calculated based on the steering amount Saa and the vehicle speed Vxa. An actual yawing amount Jra corresponding to the target yawing amount Jrt is calculated. For example, when the target yawing amount Jrt is the target yaw rate Yrt, the actual yaw rate Yra is calculated as the actual yawing amount Jra. Then, the actual yawing amount Jra and the target yawing amount Jrt are compared to calculate a steer characteristic amount Sch representing the degree of oversteer / understeer of the vehicle. For example, a deviation ΔYr (= Yra−Yrt, yaw rate deviation) between the actual yaw rate Yra and the target yaw rate Yrt is calculated as the steer characteristic amount Sch.

  The steer characteristic amount Sch can be calculated not as a single state quantity but as a correlation between a plurality of state quantities. For example, based on the mutual relationship between the deviation Δβ (= βa−βt, sideslip angle deviation) between the actual side slip angle βa and the target side slip angle βt and the yaw rate deviation ΔYr, the steering characteristic amount Sch (= K1 · Δβ + K2 · ΔYr , Where K1 and K2 are coefficients). When the (vehicle body) side slip angle or the (vehicle body) side slip angular velocity is used as the yawing amount, these target values can be set to constants (for example, the target value is “0”). Therefore, the target yawing amount Jrt can be omitted in the calculation of the steering characteristic amount Sch.

  In the second calculation block (corresponding to the second calculation means) TCY, the second state quantity Tcy is calculated. As the second state quantity Tcy, a steering speed (for example, a steering angular speed) dSa that is an operation speed of the steering operation member SW operated by the driver of the vehicle is calculated. The steering speed dSa can be calculated by time-differentiating the steering amount Saa (a value calculated based on at least one of the steering wheel angle θsw and the front wheel steering angle δfa).

  In the third calculation block (corresponding to the third calculation means) TCZ, the third state quantity Tcz is calculated. The third state quantity Tcz is a value (a lateral acceleration equivalent amount) corresponding to the lateral acceleration actually acting on the vehicle. As the third state quantity Tcz, the lateral acceleration Gya is calculated based on the detection result of the lateral acceleration sensor GY. Further, the calculated lateral acceleration Gye can be calculated as the third state quantity Tcz based on the detection result of the yaw rate sensor YR (specifically, Gye = Yra · Vxa). The third state quantity Tcz can be calculated based on the actual lateral acceleration Gya and the calculated lateral acceleration Gya (specifically, Tcz = K3 · Gya + K4 · Gye, where K3 and K4 are coefficients). That is, the third state quantity Tcz is calculated based on at least one of the detection signals of the lateral acceleration sensor GY and the yaw rate sensor YR.

  The steering amount Saa, the steering speed dSa, the turning amount (state amount representing the degree of turning motion of the vehicle) Tca, the vehicle speed Vxa, and the wheel speed Vwa [**] are sensor values obtained via the communication bus CB, And / or may be computed based on internal computed values in other systems.

  The braking control calculation block (corresponding to the control means) CTL includes a friction torque control calculation block FTC and a regenerative torque control calculation block RTC. In the friction torque control calculation block FTC, the friction torque control (friction braking control) in which the friction braking torque is applied to the wheels is executed via the friction braking means FRC. In the regenerative torque control calculation block RTC, regenerative torque control (regenerative braking control) in which regenerative braking torque is applied to the wheels is performed via the regenerative braking means RGN.

  In the friction torque control calculation block FTC, the target friction torque Pwt [**] is calculated based on the steering characteristic amount Sch (corresponding to the first state amount Tcx). Here, when the steer characteristic amount Sch is a negative sign (-), the vehicle steer characteristic is understeer (US), and when the steer characteristic quantity Sch is "0", it represents new alsteer (NS), and the steer characteristic amount. When Sch is a plus sign (+), it represents oversteer (OS).

  When the steer characteristic amount Sch indicates the degree of understeer (Sch <0), Pwt [**] = 0 (when the steer characteristic amount Sch (absolute value thereof) is not less than “0” and less than the predetermined value su1. When the steering characteristic amount Sch (absolute value) is equal to or greater than the predetermined value su1, the target friction torque Pwt [**] is calculated to increase as the steering characteristic amount Sch (absolute value) increases. The target friction torque Pwt [**] can be provided with an upper limit value “pum”.

  When the steer characteristic amount Sch represents the degree of oversteer (Sch> 0), when the steer characteristic amount Sch (absolute value thereof) is not less than “0” and less than the predetermined value so1, Pwt [**] = 0 ( When the steering characteristic amount Sch (absolute value) is equal to or greater than the predetermined value so1, the target friction torque Pwt [**] is calculated to increase as the steering characteristic amount Sch (absolute value) increases. The target friction torque Pwt [**] can be provided with an upper limit value pom (> pum).

  The friction braking means FRC controls the driving means of the brake actuator BRK (for example, an electric motor for driving a hydraulic pump, a driving means for a solenoid valve) on the basis of the target friction torque Pwt [**]. The braking torque is increased. When the driver operates the braking operation member BP, the braking torque by the friction braking control is increased with respect to the braking torque corresponding to the operation amount. When the driver is not performing a braking operation, the braking torque is increased from “0” by friction braking control.

  A sensor (for example, a pressure sensor PW [**]) that detects an actual value Pwa [**] corresponding to the target value Pwt [**] of the friction braking torque may be provided on the wheel. Based on the target value Pwt [**] and the actual value Pwa [**], the drive unit of the friction braking unit FRC is controlled so that the actual value Pwa [**] matches the target value Pwt [**]. Can be done.

  In the regenerative torque control calculation block RTC, the target regenerative torque Qwt [**] is calculated based on the steering speed dSa (corresponding to the second state quantity Tcy). For example, when the steering speed dSa is equal to or higher than a predetermined speed (predetermined value) ds0, the target regenerative torque Qwt [**] is calculated based on the turning amount Tca. The target regenerative torque Qwt [**] is calculated as target regenerative torque Qwt [**] = 0 (maintained) when the turning amount Tca is equal to or greater than “0” and less than the predetermined value tc1, and the turning amount Tca is calculated. When the value is equal to or greater than the predetermined value tc1, the target regeneration torque Qwt [**] is calculated so as to increase as the turning amount Tca increases. Note that an upper limit qwm may be provided for the target regenerative torque Qwt [**]. The target regenerative torque Qwt [**] is calculated as Qwt [**] = 0 (maintained) when the turning amount Tca is “0” or more and less than the predetermined value tc1, and the turning amount Tca is predetermined. When the value is greater than or equal to the value tc1, it can be calculated to increase stepwise as Qwt [**] = qwt (predetermined value).

  In the regenerative braking means RGN, the drive means of the electric motor MT (regenerative braking device RGN) is controlled based on the target regenerative torque Qwt [**], and the regenerative braking torque of the wheels is increased. When the driver is not performing a braking operation, the regenerative braking torque is increased from “0” by the regenerative braking control. The wheel may be provided with a sensor that detects an actual value Qwa [**] corresponding to the target value Qwt [**] of the regenerative braking torque. Based on the target value Qwt [**] and the actual value Qwa [**], the drive means of the regenerative braking means RGN is controlled so that the actual value Qwa [**] matches the target value Qwt [**]. Is done.

  In the target regenerative torque calculation block QWT, the target regenerative torque Qwt [**] increases when the braking operation amount Bsa acquired in the braking operation amount acquisition calculation block BSA is equal to or less than a predetermined operation amount (predetermined value) bsa1. Is called. On the other hand, when the braking operation amount Bsa is larger than the predetermined operation amount bsa1, the increase in the target regenerative torque Qwt [**] is invalidated (Qwt [**] = 0), and the state before the start of the regenerative braking control Retained. For example, the predetermined operation amount bsa1 may be “0 (a value corresponding to a state in which the braking operation member BP is not operated by the driver)”. The regenerative braking torque is increased only when the driver's braking operation is not performed (bsa1 = 0), and the regenerative braking control is disabled (prohibited) when the braking operation is performed (bsa1> 0). ).

  The regenerative braking means RGN is provided at least on the front wheels. In the target regeneration torque calculation block QWT, the target regeneration torque Qwt [f *] for the front wheels is increased, and the target regeneration torque Qwt [r *] for the rear wheels can be invalidated (Qwt [r *] = 0). ). That is, the regenerative braking torque of the front wheels is increased, and the regenerative braking torque of the rear wheels is not increased (the regenerative braking torque before the execution of the regenerative braking control is maintained). The front wheel lateral force is reduced by the increase in the regenerative braking torque of the front wheels, and the regenerative braking torque of the rear wheels is not increased (maintained) to secure the rear wheel lateral force, so that the stability of the vehicle can be secured.

  In the regenerative torque control calculation block RTC, the target regenerative torque Qwt [**] is set based on the steering speed dSa, but the steering speed peak value storage calculation block (stores the steering speed peak value (peak steering speed) dSap). A DSAP is provided, and the target regenerative torque Qwt [**] can be calculated based on the peak value (maximum value) dSap. In the steering speed peak value storage calculation block DSAP, the value of the steering speed dSa is continuously stored, and the peak steering speed (maximum steering speed) dSap is calculated based on the time-series value of the stored steering speed dSa. Specifically, the peak steering speed dSap [n−1] until the previous calculation process is stored, and this peak value dSap [n−1] is compared with the steering speed dSa [n] of the current calculation process. Then, the larger one of the peak steering speed dSap [n-1] and the steering speed dSap [n] of this processing is calculated as the peak steering speed dSap [n] and a new peak steering speed dSap [ n]. The peak steering speed dSap is set to “0” after a predetermined time tk1 has elapsed. The subscript [n-1] represents the previous calculation cycle, and the subscript [n] represents the current calculation cycle. There is a temporal shift (phase difference) between the turning amount Tca and the steering speed dSa, but this phase difference can be compensated by using the peak steering speed dSap.

  With reference to FIG. 4, a first calculation processing example in the regenerative torque control calculation block RTC will be described. In the above description, when the steering speed dSa is equal to or higher than the predetermined speed (predetermined value) ds0, the target regenerative torque Qwt [**] is calculated based on the turning amount Tca, but in this embodiment, the norm based on the steering speed dSa is calculated. The target regenerative torque Qwt [**] is calculated by setting the amount Trf according to the steering state (whether or not it is transient steering).

  In the transient steering determination calculation block KAT, it is determined whether or not the steering operation state is a transient steering state (a steering operation state in which the steering amount of the steering operation member is continuously increased or decreased). Here, the transient steering state is a state of a steering operation that fluctuates when transitioning from a steady steering state where the steering amount is constant to another steady steering state. For example, in the transient steering state, the steering direction continuously changes from side to side. In the transient steering discrimination calculation block KAT, a state where the transient steering state is not discriminated (transient steering non-discrimination state) is set as an initial state. Then, a state in which the transient steering state is determined (transient steering determination state) is determined based on the steering amount Saa.

  The transient steering discrimination calculation block KAT includes a steering direction calculation block DSTR and a steering state determination block KTI. In the steering direction calculation block DSTR, based on the steering amount Saa, the steering direction Dstr is one direction (that is, one of the left direction and the right direction) or the other direction (that is, the left direction and the right direction). Is the other of the two directions different from the one direction). Specifically, any one of the straight traveling direction, the left steering direction, and the right steering direction is calculated as the steering direction Dstr. For example, the steering direction Dstr is determined based on the absolute value and sign of the steering amount Saa. When the absolute value of the steering amount Saa is less than the predetermined value saa0 (a value near zero), the straight traveling direction is determined as the steering direction Dstr. When the absolute value of the steering amount Saa is equal to or greater than the predetermined value saa0 and the sign of the steering amount Saa is a positive sign (+), the left steering direction (corresponding to the left turn of the vehicle) is determined as the steering direction Dstr. . When the absolute value of the steering amount Saa is equal to or greater than the predetermined value saa0 and the sign of the steering amount Saa is negative (−), the right steering direction (corresponding to the right turn of the vehicle) is determined as the steering direction Dstr. The

  In the steering state determination block KTI, a transient steering state (a steering operation state in which increase or decrease of the steering amount is continuously performed) is determined based on the steering direction Dstr. The determination result is output as a control flag Kat. When it is determined that the steering direction Dstr is one direction (for example, the left direction), the transient steering state is not determined and Kat = 0 is output. When the steering direction Dstr is determined to be one direction (for example, the left direction) and then continuously determined to be the other direction (for example, the right direction), the transient steering state is determined and Kat = 1 is output. Specifically, after the steering direction Dstr is calculated as one direction, the other direction is calculated, and the time (transition time) required for transition from one direction of the steering direction Dstr to the other direction is a predetermined time (predetermined value). When it is less than tka0, the transient steering state is determined. Note that, in the steering state determination block KTI, Kat = 0 is set as an initial state of the determination result. When the steering direction Dstr is a straight traveling direction, Kat = 0 is determined unless the steering direction Dstr is a transition from one direction to the other direction and the transition time is less than tka0.

  The transient steering determination calculation block KAT is configured by a switch-over / switchback steering identification calculation block (identification calculation block) SJH and a steering state determination block KTI instead of the steering direction calculation block DSTR. In the identification calculation block SJH, based on the steering amount Saa, it is identified whether the steering state is holding steering, additional steering, or switching back steering. Here, “holding steering” is a state in which the steering amount Saa is substantially constant. Further, the “increase state” is a state in which the steering amount Saa is increased (a state in which the steering amount Saa is moved away from the steering neutral position), and the “return state” is a state in which the steering amount Saa is decreased (the steering amount). Saa is approaching the steering neutral position). The steering state identification result Sjh is output to the steering state determination block KTI.

  In the steering state determination block KTI, the transient steering state is determined based on the discrimination result Sjh of the additional steering and the return steering. The determination result is output as a control flag Kat. The determination result is set to Kat = 0 as an initial state. When the identification result Sjh is shifted from holding steering or holding steering to transition to steering, the transient steering state is not discriminated and Kat = 0 is output. Then, when the identification result Sjh increases and transitions continuously from steering to return steering, the transient steering state is determined and Kat = 1 is output. Here, “continuously” refers to a case where the time for transition from the additional steering to the switchback steering (referred to as the transition time as in the case of determination by the steering direction Dstr) is less than a predetermined time (predetermined value) tka1 Say. For example, after the steering amount Saa continues to be substantially constant (a value in a predetermined range that is ± saa1 (predetermined value)) for a predetermined time (predetermined value) tsa1 or more (after holding steering), the steering amount Saa is If it increases, Kat = 0 is determined. Then, Kat = 1 is determined when the steering amount Saa continuously decreases after the steering amount Saa increases. The transient steering state can be determined not only in the case of additional steering / return steering from the straight traveling state but also in the case of additional steering / return steering from the steady turning state.

  Holding steering, additional turning steering, and switching back steering can be identified based on the sign of the steering speed dSa. After the steering speed dSa continues below the predetermined speed (predetermined value) dsa0 for a predetermined time (predetermined value) tsa2 (after holding steering), the steering speed dSa is equal to or higher than the predetermined speed dsa0 (positive increase) In the case of steering), Kat = 0 (transient steering non-discrimination state) is discriminated. When the steering speed dSa is equal to or higher than the predetermined speed dsa0 (positive steering), the steering speed dSa is continuously equal to or lower than the predetermined speed -dsa0 and becomes negative (switchback steering). The discriminating state of the transient steering) is discriminated. Here, “continuously” means that, as described above, the transition from the additional steering to the switching back steering is made within the transition time less than the predetermined time (predetermined value) tka2.

  In the steering state determination block KTI, the transient steering state can be determined based on the steering direction Dstr and / or the increase / return identification result Sjh. The determination reliability can be improved by a plurality of transient steering determinations. In the transient steering discrimination calculation block KAT, transient steering discrimination is performed based on at least one of the steering amount Saa and the steering speed dSa.

  In the reference amount calculation block TRF, the reference amount Trf (Trf1, Trf2) is calculated based on the control flag Kat and the steering speed dSa using the calculation map. When Kat = 0, as indicated by the characteristic Chc1, when the steering speed dSa is less than the predetermined speed ds1, the first reference amount Trf1 is calculated as the predetermined amount tr1, and the steering speed dSa is equal to or higher than the predetermined speed (predetermined value) ds1. When the steering speed dSa is less than the predetermined speed (predetermined value) ds2, the first reference amount Trf1 is calculated to decrease as the steering speed dSa increases. When the steering speed dSa is equal to or higher than the predetermined speed ds2, the first reference amount Trf1 is calculated. It is calculated to tr2. When Kat = 1, instead of the first reference amount Trf1, as indicated by a characteristic Chc2 smaller than the characteristic Chc1, when the steering speed dSa is less than the predetermined speed ds1, the second reference amount Trf2 is a predetermined amount tr3 (< When the steering speed dSa is equal to or higher than the predetermined speed ds1 and lower than the predetermined speed ds2, the second reference amount Trf2 is calculated to decrease as the steering speed dSa increases, and the steering speed dSa is equal to or higher than the predetermined speed ds2. In this case, the second reference amount Trf2 is calculated to be a predetermined amount tr4 (<tr2). The second reference amount Trf2 (reference amount Trf when transient steering is determined) is always smaller than the first reference amount Trf1 (reference amount Trf when transient steering is not determined) regardless of the value of the steering speed dSa. Is calculated. From the reference amount calculation block TRF, when Kat = 0, the first reference amount Trf1 is output to the target regenerative torque calculation block QWT, and when Kat = 1, the second reference amount Trf2 is output to the target regenerative torque calculation block QWT. Is output.

  Further, instead of determining the second reference amount Trf2 based on the calculation map for the steering speed dSa, the second reference amount Trf2 can be calculated as a value smaller than the first reference amount Trf1 by a predetermined value trf0. That is, the second reference amount Trf2 is determined by Trf2 = Trf1-trf0. At this time, since the first reference amount Trf1 is calculated based on the steering speed dSa, the second reference amount Trf2 is indirectly calculated based on the steering speed dSa.

  In the target regenerative torque calculation block QWT, the target regenerative torque Qwt [**] is calculated based on the lateral acceleration equivalent amount (third state amount) Tcz and the reference amount Trf (Trf1, Trf2). When Kat = 0 (when transient steering is not determined), the lateral acceleration equivalent amount Tcz is compared with the first reference amount Trf1. When the lateral acceleration equivalent amount Tcz is equal to or smaller than the first reference amount Trf1, the target regenerative torque Qwt [**] is calculated as “0”, and the target regenerative torque Qwt [**] is not increased. When the lateral acceleration equivalent amount Tcz exceeds the first reference amount Trf1, the target regenerative torque Qwt [**] as the deviation ΔTc (= Tcz−Trf1) between the lateral acceleration equivalent amount Tcz and the first reference amount Trf1 increases. Is increased so that the target regeneration torque Qwt [**] is increased. When Kat = 1 (when determining transient steering), the lateral acceleration equivalent amount Tcz and the second reference amount Trf2 are compared. When the lateral acceleration equivalent amount Tcz is equal to or smaller than the second reference amount Trf2, the target regenerative torque Qwt [**] is calculated as “0”, and the target regenerative torque Qwt [**] is not increased. When the lateral acceleration equivalent amount Tcz exceeds the second reference amount Trf2, the target regenerative torque Qwt [**] as the deviation ΔTc (= Tcz−Trf2) between the lateral acceleration equivalent amount Tcz and the second reference amount Trf2 increases. Is increased so that the target regeneration torque Qwt [**] is increased. An upper limit qw1 can be set for the target regenerative torque Qwt [**].

  In the reference amount calculation block TRF, the reference amount Trf (Trf1, Trf2) can be calculated based on the peak value (peak steering speed) dSap of the steering speed instead of the steering speed dSa. In this case, the steering speed peak value storage calculation block steering speed peak value storage calculation block DSAP calculates the peak steering speed dSap based on the steering speed dSa. Specifically, the peak steering speed dSap [n-1] until the previous calculation cycle is stored, and the peak value dSap [n-1] is compared with the steering speed dSa [n] of the current calculation cycle. . The larger value of the peak steering speed dSap [n-1] up to the previous calculation cycle and the steering speed dSa [n] of the current calculation cycle is the peak steering speed dSap [ n] and is stored as a new peak steering speed dSap [n]. The subscript [n-1] represents the previous operation cycle, and the subscript [n] represents the current operation cycle. For example, referring to FIG. 2A, the steering speed dSa for each control cycle is updated as the peak steering speed dSap until time p1, and the value of the steering speed dSa at time p1 (point P) is peak steering after time p1. Maintained as speed dSap.

  With reference to FIG. 5, a second calculation processing example in the regenerative torque control calculation block RTC will be described. Note that the calculation process of the transient steering determination calculation block KAT is the same as that in the above-described first calculation process example, and thus the description thereof is omitted.

  In the threshold value calculation block SKE, threshold values Stc, Sds, and Sdt are calculated based on the control flag Kat using predetermined values that are preset and stored. In the case of the threshold value (threshold amount) Stc for the lateral acceleration equivalent amount Tcz, when Kat = 0 (when transient steering is not determined), the first threshold amount (predetermined value) stc1 is set as the threshold amount Stc. When Kat = 1 (when determining the transient steering), a second threshold amount (predetermined value) stc2 (<stc1) smaller than the first threshold amount stc1 is set as the threshold amount Stc. In the case of the threshold value (threshold speed) Sds for the steering speed dSa, when Kat = 0 (when transient steering is not determined), the first threshold speed (predetermined value) sds1 is set as Sds, and Kat = When the value is 1 (when determining the transient steering), a second threshold speed (predetermined value) sds2 (<sds1) smaller than the first threshold speed sds1 is set as the threshold speed Sds. In the case of the threshold value (threshold change amount) Sdt for the turning change amount dTc, the first threshold change amount (predetermined value) sdt1 is the threshold change amount when Kat = 0 (when transient steering is not determined). Sdt is set, and when Kat = 1 (when determining the transient steering), the second threshold change amount (predetermined value) sdt2 (<sdt1) smaller than the first threshold change amount stc1 is the threshold change amount Sdt. Set as

  From the threshold calculation block SKE, the first threshold values stc1, sds1, and sdt1 are output to the target regenerative torque calculation block QWT when Kat = 0, and the second threshold value stc2 when Kat = 1. , Sds2 and sdt2 are output to the target regenerative torque calculation block QWT.

  In the target regenerative torque calculation block QWT, based on the lateral acceleration equivalent amount Tcz, the steering speed dSa, the turning change amount dTc, and the respective threshold values (threshold amount Stc etc.) for each state quantity (Tcz etc.). The target regenerative torque Qwt [**] is calculated. The target regenerative torque calculation block QWT includes a regenerative control execution determination unit and a regenerative torque increase amount setting unit. In the regenerative torque increase amount setting unit, a braking torque amount Qwt [**] to be increased is calculated and set. The regeneration control execution determination unit determines whether or not an increase amount Qwt [**] of the braking torque is output. That is, the regeneration control execution determination unit determines whether braking control is possible. When the regenerative control execution determination unit determines that it is valid (control permission), the target regenerative torque Qwt [**] is output, and when it is determined invalid (control prohibition), the target regenerative torque Qwt [**] is “ 0 "and the regenerative braking torque is not increased.

  The regenerative torque increase amount setting unit calculates the regenerative torque increase amount Qwt [**] based on the lateral acceleration equivalent amount Tcz. Specifically, calculation is performed so that the target regenerative torque Qwt [**] increases as the lateral acceleration equivalent amount Tcz increases. An upper limit value qw1 can be set for the target regenerative torque Qwt [**].

  Further, the target regenerative torque Qwt [**] can be calculated based on the deviation ΔTc between the lateral acceleration equivalent amount Tcz and the threshold amount Stc (stc1, stc2). When Kat = 0 (when transient steering is not determined), the lateral acceleration equivalent amount Tcz and the first threshold amount stc1 are compared. When the lateral acceleration equivalent amount Tcz is equal to or smaller than the first threshold amount stc1, the target regenerative torque Qwt [**] is calculated as “0”, and the target regenerative torque Qwt [**] is not increased. When the lateral acceleration equivalent amount Tcz exceeds the first threshold amount stc1, the target regenerative torque Qwt [*] according to the increase in the deviation ΔTc (= Tcz−stc1) between the lateral acceleration equivalent amount Tcz and the first threshold amount stc1. *] Is calculated to increase, and the target regeneration torque Qwt [**] is increased. When Kat = 1 (when determining the transient steering), the lateral acceleration equivalent amount Tcz and the second threshold amount stc2 are compared. When the lateral acceleration equivalent amount Tcz is equal to or smaller than the second threshold amount stc2, the target regenerative torque Qwt [**] is calculated as “0”, and the target regenerative torque Qwt [**] is not increased. When the lateral acceleration equivalent amount Tcz exceeds the second threshold amount stc2, the target regenerative torque Qwt [*] according to an increase in the deviation ΔTc (= Tcz−stc2) between the lateral acceleration equivalent amount Tcz and the second threshold amount stc2. *] Is calculated to increase, and the target regeneration torque Qwt [**] is increased. Similarly, an upper limit value qw1 can be set for the target regenerative torque Qwt [**].

  The regeneration control execution determination unit is based on a comparison result between the lateral acceleration equivalent amount Tcz and the threshold amount Stc, a comparison result between the steering speed dSa and the threshold speed Sds, and a comparison result between the turning change amount dTc and the threshold change amount Sdt. Thus, it is determined whether or not the braking control can be executed. When Kat = 0 (when transient steering is not discriminated), the lateral acceleration equivalent amount Tcz and the first threshold amount stc1, the steering speed dSa and the first threshold speed sds1, and the turning change amount dTc are first determined. The threshold change amount sdt1 is compared. When all of Tcz> stc1, dSa> sds1, and dTc> sdt1 are satisfied, control execution is permitted (valid state), and the target calculated by the regenerative torque increase amount setting unit from the target regenerative torque calculation block QWT. Regenerative torque Qwt [**] is output. However, if at least one of these three conditions is not satisfied, control execution is prohibited (invalid state), and the target regenerative torque calculation block QWT does not output the target regenerative torque Qwt [**] (Qwt [ **] = 0). When Kat = 1 (when determining the transient steering), the lateral acceleration equivalent amount Tcz and the second threshold amount stc2, the steering speed dSa and the second threshold speed sds2, and the turning change amount dTc and the second threshold are obtained. The change amount sdt2 is compared. When all of Tcz> stc2, dSa> sds2, and dTc> sdt2 are satisfied, control execution is permitted (valid state), and the target calculated by the regenerative torque increase amount setting unit from the target regenerative torque calculation block QWT. Regenerative torque Qwt [**] is output. However, if at least one of the above three conditions is not satisfied, control execution is prohibited (invalid state), and the target regenerative torque calculation block QWT does not output the target regenerative torque Qwt [**] (Qwt [ **] = 0). Each threshold has a relationship of stc1> stc2, sds1> sds2, and sdt1> sdt2.

  In the target regenerative torque calculation block QWT, whether or not control can be executed can be determined based on the peak value (peak steering speed) dSap of the steering speed instead of the steering speed dSa. That is, whether control is possible or not can be determined based on a comparison between the steering speed peak value dSap and the threshold speed Sds. The steering speed peak value dSap is calculated using the same method as described above.

  At least one of the adjustments of the threshold amount Stc, the threshold speed Sds, and the threshold change amount Sdt performed in the threshold calculation block SKE may be omitted. If this adjustment is omitted, the same threshold value is set when transient steering is not discriminated (Kat = 0) and when discriminating (Kat = 1). Further, the control availability determination based on the comparison between the turning change amount dTc and the threshold change amount Sdt can be omitted.

  FIG. 6 is a control flow diagram for explaining an example of calculation processing in the regeneration control execution determination unit of the target regenerative torque calculation block QWT.

  First, initialization is performed in step S110. Here, the threshold values Stc, Sds, and Sdt are set to the first threshold values stc1, sds1, and sdt1, which are initial values (values when the transient steering state is not determined). In step S120, a sensor value and / or an internal calculation value of another system is read. In step S130, the above-described respective state quantities (such as the turning amount Tca) are calculated.

  In the determination step S140, the state of the steering operation by the driver is a transient steering state (a steering operation state in which the steering amount of the steering operation member is continuously increased or decreased. For example, in the transient steering state, the steering direction Is continuously changing) or not. The transient steering state is determined based on the steering amount Saa. If the transient steering state is not determined in step S140, the calculation process proceeds to step S150. In step S150, threshold amount Stc (threshold value corresponding to turning amount Tca), threshold speed Sds (threshold value corresponding to steering speed dSa), and threshold change amount Sdt (corresponding to turning change amount dTc). Threshold value) is set to the first threshold values stc1, sds1, and sdt1, respectively.

  Next, in steps S160, S170, and S180, it is determined whether or not to execute braking control (increase braking torque) (whether or not to prohibit). In step S160, it is determined whether the lateral acceleration equivalent amount (for example, actual lateral acceleration) Tcz is larger than the first threshold amount dtc1. If Tcz> dtc1 and the determination is affirmative (Yes) in step S160, the arithmetic processing proceeds to step S170. In step S170, it is determined whether the steering speed (for example, the steering angular speed) dSa is greater than the first threshold speed sds1. If dSa> sds1, and an affirmative determination (Yes) is made in step S170, the arithmetic processing proceeds to step S180. In step S180, it is determined whether the turning change amount (for example, yaw angular acceleration) dTc is larger than the first threshold change amount sdt1. If dTc> sdt1, and an affirmative determination (Yes) is made in step S180, the arithmetic processing proceeds to step S190. In step S190, the braking control is enabled, and the target regenerative torque Qwt [**] calculated by the regenerative torque increase amount setting unit is transmitted to the braking means MBR.

  If a negative determination (No) is made in at least one of steps S160, S170, and S180, the calculation process proceeds to step S200, the braking control is disabled, and Qwt [**] = 0.

  When the transient steering state is determined in step S140, the calculation process proceeds to step S210. In step S210, threshold values Stc, Sds, and Sdt are set to second threshold values stc2, sds2, and sdt2, respectively. The second threshold value is smaller than the first threshold value and has a relationship of stc2 <stc1, sds2 <sds1, sdt2 <sdt1.

  As in the case of non-discrimination of transient steering, in steps S220, S230, and S240, it is determined whether or not the brake control (braking torque increase) at the time of discrimination of transient steering can be executed. In step S220, it is determined whether the lateral acceleration equivalent amount (eg, lateral acceleration) Tcz is larger than the second threshold amount stc2. If Tcz> stc2 and an affirmative determination (Yes) is made in step S220, the arithmetic processing proceeds to step S230. In step S230, it is determined whether the steering speed (for example, the steering angular speed) dSa is greater than the second threshold speed sds2. If dSa> sds2, and an affirmative determination (Yes) is made in step S230, the arithmetic processing proceeds to step S240. In step S240, it is determined whether the turning change amount (for example, yaw angular acceleration) dTc is larger than the second threshold change amount sdt2. If dTc> sdt2, and an affirmative determination (Yes) is made in step S180, the arithmetic processing proceeds to step S190. In step S190, the braking control is enabled, and the target regenerative torque Qwt [**] calculated by the regenerative torque increase amount setting unit is transmitted to the braking means MBR.

  If a negative determination (No) is made in at least one of steps S220, S230, and S240, the calculation process proceeds to step S200, the braking control is disabled, and Qwt [**] = 0.

  At least one of the determination step (S170, S230) for the steering speed dSa and the determination step (S180, S240) for the turning change amount dTc may be omitted. Further, the threshold speed Sds is changed (change from the first threshold speed sds1 to the second threshold speed sds2), and the threshold change amount Sdt is changed (from the first threshold change amount sdt1 to the second threshold change). At least one of the changes to the quantity sdt2) may be omitted. That is, even when determining transient steering, the first threshold speed sds1 is set as the threshold speed Sds and / or the first threshold change amount sdt1 is set as the threshold change amount Sdt. Furthermore, in the determination step (S170, S230) for the steering speed dSa, the steering speed peak value dSap can be used instead of the steering speed dSa.

  FIG. 7 is a time-series diagram for explaining the operation and effect of the vehicle braking control apparatus according to the embodiment of the present invention. Here, for the calculation of the target regenerative torque Qwt [**], a method using the reference amount Trf is shown. Three cases (Tcz1, Tcz2, Tcz3) are shown according to the change state of the lateral acceleration equivalent amount (third state amount) Tcz.

  Until the time (time point) t0, the steering operation is not performed, the lateral acceleration equivalent amount Tcz1 and the like are “0 (straight traveling)”, and the control flag Kat is “0 (non-transient steering state)” as an initial value. The first reference amount Trf1, which is the threshold value (reference amount Trf) of the execution condition (for example, start condition) of the braking control (increase of braking torque), is calculated to the maximum value tr1. The steering operation is started by the driver at time t0, and the first reference amount Trf1 is calculated by being reduced from the predetermined amount tr1 based on the steering speed dSa (or the peak steering speed dSap) (see the broken line). . At this time, the transient steering determination calculation block KAT continues the state in which the transient steering state is not determined (Kat = 0), and the reference amount calculation block TRF outputs the first reference amount Trf1 as the reference amount Trf. At time t1, the transient steering state is determined by the transient steering determination calculation block KAT (Kat = 1), and the reference amount Trf output from the reference amount calculation block TRF is changed from the first reference amount Trf1 to the second reference amount Trf2 ( <Trf1) is changed (switched). For example, the second reference amount Trf2 can be calculated to a value smaller than the first reference amount Trf1 by a predetermined amount trf0.

  First, a case where a relatively large lateral acceleration equivalent amount Tcz (Tcz1) is generated in response to the steering operation will be described. When the lateral acceleration equivalent amount Tcz1 is equal to or less than the reference amount Trf, the regenerative braking control is not executed. At the time t2 when the lateral acceleration equivalent amount Tcz1 exceeds the reference amount Trf (the first reference amount Trf1 because it is a non-transient steering state), the execution of the regenerative braking control is started and the regenerative braking torque is increased. At this time, the increase amount Qwt [**] of the braking torque is calculated based on a deviation ΔTc (= Tcz1−Trf1) between the lateral acceleration equivalent amount Tcz1 and the reference amount Trf (first reference amount Trf1). Further, if the stability of the vehicle is not ensured even if the target regenerative torque Qwt [**] is increased (for example, when the steering characteristic amount Sch exceeds a predetermined value so1), the target friction torque is reached after time t2. Pwt [**] is increased. Such a situation may occur when a sudden steering is performed on a road surface having a high friction coefficient (for example, a dry asphalt road).

  When the lateral acceleration equivalent amount Tcz exceeds the first reference amount Trf1, there is a high probability that a rapid rolling motion is also generated along with a rapid yawing motion. Even when the transient steering is not determined, the regenerative braking torque is increased based on the comparison result between the reference amount Trf determined according to the steering speed dSa and the lateral acceleration equivalent amount Tcz. Movement can also be stabilized. If the regenerative braking torque alone is insufficient to ensure the vehicle stability, the friction braking torque is increased and the vehicle stability can be reliably maintained.

  Next, a case where a transient steering operation is performed although the lateral acceleration equivalent amount Tcz (Tcz2) generated is relatively small will be described. At time t1, it is determined that “the steering state is a transient steering state”, and the reference amount Trf is changed to a relatively small value as compared to when the transient steering is not determined. That is, the reference amount Trf is changed from the first reference amount Trf1 to the second reference amount Trf2 (<Trf2). When the lateral acceleration equivalent amount Tcz2 is equal to or less than the reference amount Trf, the regenerative braking control is not performed. At the time t3 when the lateral acceleration equivalent amount Tcz2 exceeds the reference amount Trf (second reference amount Trf2 because of the transient steering state), the execution of the regenerative braking control is started and the regenerative braking torque is increased. At this time, the increase amount Qwt [**] of the braking torque is calculated based on a deviation ΔTc (= Tcz2−Trf2) between the lateral acceleration equivalent amount Tcz2 and the reference amount Trf (second reference amount Trf2). Further, if the stability of the vehicle is not ensured even if the target regenerative torque Qwt [**] is increased (for example, when the steering characteristic amount Sch exceeds the predetermined value so1), the target friction torque after the time t3. Pwt [**] is increased. Such a situation may occur when transient steering is performed on a road surface with a low friction coefficient (for example, a snowy road).

  When transient steering is performed, the possibility that the vehicle stability is reduced is higher than when transient steering is not performed. When the transient steering state is determined, the reference amount Trf is changed (adjusted) to a smaller value than when the transient steering state is not determined, so that vehicle stability (particularly yawing stability) is ensured. Can be maintained. Furthermore, since the transient steering state is not discriminated at the time of additional steering of the first steering, an early increase in regenerative torque is suppressed, and the turning ability of the vehicle (followability of turning behavior with respect to the steering operation) can be ensured. Similarly to the above, in order to ensure vehicle stability, when the regenerative braking torque alone is insufficient, the friction braking torque is increased and the vehicle stability can be reliably maintained.

  Further, there may be an intermediate lateral acceleration equivalent amount Tcz (Tcz3) between the lateral acceleration equivalent amount Tcz1 (relatively large) and the lateral acceleration equivalent amount Tcz2 (relatively small). In this case, at the time t1 when the reference amount Trf is switched from the first reference amount Trf1 to the second reference amount Trf2, the lateral acceleration equivalent amount Tcz3 exceeds the reference amount Trf (second reference amount Trf2), and regeneration is performed. Braking control is started. Also in this case, the increase amount Qwt [**] of the regenerative braking torque is calculated based on the deviation ΔTc (= Tcz3−Trf2) between the lateral acceleration equivalent amount Tcz3 and the reference amount Trf (second reference amount Trf2). . If the stability of the vehicle is not ensured even if the target regenerative torque Qwt [**] is increased (for example, when the steer characteristic amount Sch exceeds a predetermined value so1), the target friction torque after the time t1. Pwt [**] is increased.

  Similarly, when the execution start of the regenerative braking control is determined based on the threshold values Stc, Sds, and Sdt, the regenerative braking torque is increased when the execution condition of the start braking control is satisfied. Then, in order to ensure vehicle stability, when the increase of the regenerative braking torque is not sufficient (for example, when the steering characteristic amount Sch exceeds the predetermined value so1), the increase of the regenerative braking torque is started. After that, the friction braking torque is increased.

  The above-described regenerative braking control (regenerative braking torque increase) can be performed only on the front wheels and not on the rear wheels. That is, when the lateral acceleration equivalent amount Tcz exceeds the reference amount Trf, the regenerative braking torque of the front wheels is increased and the regenerative braking torque of the rear wheels is not increased (the braking torque before the regenerative braking control is executed is held). ). Since the front wheel lateral force is reduced by the increase in the regenerative braking torque of the front wheels and the regenerative braking torque of the rear wheels is not increased (maintained), the rear wheel lateral force is ensured and the stability of the vehicle can be maintained.

  The above-described regenerative braking control (regenerative braking torque increase) may be performed when the steering characteristic of the vehicle is oversteer and not performed when understeering. In this case, the steer characteristic amount Sch can be an oversteer state amount representing the degree (level) of oversteer of the vehicle. Furthermore, the regenerative braking means RGN is provided at least on the front wheels and can be omitted for the rear wheels. The case where the oversteer tendency is eliminated requires an earlier and larger braking torque than the case where the understeer tendency is eliminated. Since the regenerative braking torque is applied to the front wheels, the oversteer tendency can be efficiently suppressed.

  TCA: turning amount acquisition means, TCX: first calculation means, TCY: second calculation means, TCZ: third calculation means, CTL: control means, FRC: friction braking means, RGN: regenerative braking means, Yra: yaw rate, Saa ... Steering amount, Tcx ... First state amount, Sch ... Steer characteristic amount, Tcy ... Second state amount, dSa ... Steering speed, Tcz ... Third state amount, Gya, Gye ... Lateral acceleration equivalent amount

Claims (10)

  Friction braking means for applying friction braking torque to wheels of the vehicle, regenerative braking means for applying regenerative braking torque to the wheels, turning amount acquisition means for acquiring a turning amount indicating the degree of turning state of the vehicle, and A first calculating means for calculating a first state quantity based on the turning amount; a second calculating means for calculating a second state quantity different from the first state quantity based on the turning amount; and a driver of the vehicle. Independent of the braking operation, the friction braking control for increasing the friction braking torque based on the first state quantity is executed, and the regenerative braking control for increasing the regenerative braking torque based on the second state quantity is executed. A vehicle braking control device comprising a control means.   2. The vehicle braking control apparatus according to claim 1, wherein the control means starts increasing the friction braking torque after starting increasing the regenerative braking torque.   The vehicle braking control device according to claim 1 or 2, wherein the regenerative braking means is provided on at least a front wheel of the wheels.   4. The vehicle braking control device according to claim 1, wherein the turning amount acquisition unit acquires the yaw rate of the vehicle and a steering amount of a steering operation member operated by a driver of the vehicle as the turning amount. 5. The first calculation means calculates a steer characteristic amount that represents the degree of the steer characteristic of the vehicle based on the yaw rate and the steering amount as the first state quantity, and the second calculation means calculates the first state quantity. A vehicle braking control device that calculates a steering speed of the steering operation member based on the steering amount.   The vehicle braking control device according to claim 4, further comprising third calculation means for calculating a third state quantity different from the first state quantity and the second state quantity based on the turning amount, The control means increases the regenerative braking torque when the third state quantity exceeds a reference value, determines a transient steering state in which the steering quantity continuously increases or decreases based on the steering quantity, and determines the transient A vehicle braking control apparatus, wherein the reference value is changed to a small value when determining a steering state.   6. The vehicle braking control apparatus according to claim 5, wherein the control means sets the reference value based on the steering speed.   7. The vehicle braking control device according to claim 6, further comprising storage means for storing a peak value of the steering speed based on the steering speed, wherein the control means is based on the peak value of the steering speed. A braking control device for a vehicle, wherein a reference value is set.   8. The vehicle braking control apparatus according to claim 5, wherein the turning amount acquisition means acquires at least one of the yaw rate of the vehicle and the lateral acceleration of the vehicle as the turning amount, and the control. The means calculates a lateral acceleration equivalent amount corresponding to the lateral acceleration of the vehicle based on the acquisition result of the turning amount acquisition means as the third state quantity.   11. The vehicle braking control device according to claim 1, further comprising: a braking operation amount acquisition unit that acquires a braking operation amount of a braking operation member that is operated by a driver of the vehicle. The vehicle is characterized in that the regenerative braking torque is increased when the braking operation amount is equal to or less than a predetermined operation amount, and the regenerative braking torque is maintained when the braking operation amount is larger than the predetermined operation amount. Braking control device.   12. The vehicle brake control device according to claim 11, wherein the predetermined operation amount is a value corresponding to a state in which the brake operation member is not operated by a driver of the vehicle. apparatus.

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