JP5699449B2 - Vehicle motion control device - Google Patents

Description

  The present invention relates to a vehicle motion control device that increases the braking torque of a wheel to improve the stability of the vehicle.

  Patent Document 1 states that “a course maintaining means (anti-lock) is used when a lateral velocity or a lateral acceleration reaches a preset value in order to avoid an unstable traveling state resulting from a side skid of the vehicle. The mechanism etc.) is automatically controlled. "

  Patent Document 2 provides “a method for controlling driving stability that can respond as quickly as possible to an anticipated unstable driving situation by intervention to alleviate or avoid a critical driving situation. For the purpose of this, pre-braking intervention is performed on the front wheels outside the curve in anticipation of sudden steering based on the average steering wheel acceleration (| maximum SWAP | / (T2-T1)) etc. until the maximum steering wheel angular velocity is reached. Then, as long as the condition of | SWAPt−maximum SWAP | / (t−T2)> reference amount 4 is satisfied, the pre-braking intervention is continued (where SWAPt is the steering wheel angular velocity at an arbitrary time point t). The braking torque applied by prior braking intervention depends on the vehicle speed and / or the maximum steering wheel angular velocity (maximum SWAP) That. Vehicle speed, and / or the larger the maximum SWAP, braking torque is great. "It has been described.

  Also, “In extreme counter-steering behavior when driving on a curve with high lateral acceleration, rolling motion occurs due to the large lateral dynamics of the car body. Based on the steering wheel angular velocity and lateral acceleration, For the purpose of determining the tendency of the stable running state and performing the pre-braking intervention in the stable running state, SWAP (steering wheel angular velocity) <reference amount 5 at the time when the steering wheel angle crosses zero. And, when the condition of LA (lateral acceleration)> reference amount 6 is satisfied, pre-braking intervention is performed ”.

British Patent No. 1297976 US Pat. No. 6,957,873

  By the way, the yawing motion related to the vehicle stability is influenced not only by the steering speed but also by the traveling road surface state of the vehicle and the increase / decrease state of the steering amount. For example, when the road friction coefficient such as a dry asphalt road surface is high, a fast yawing motion is generated against abrupt steering, but when the friction coefficient such as a snow pressure road surface is low, the yawing motion is not so much generated. . When braking control is suitably performed for the case of a high friction coefficient, the wheel lateral force is insufficient for a low friction coefficient. Conversely, if braking control is suitably performed for the case of a low friction coefficient, insufficient braking occurs when the friction coefficient is high. When the braking control is performed by predicting the stability of the vehicle, it is desirable to consider the road surface condition (road surface friction coefficient). In addition, it is necessary to execute the braking control in accordance with the increase / decrease state of the steering amount (steering additional steering or switching back steering). An object of the present invention is to provide a vehicle motion control device that can appropriately ensure vehicle stability by braking control according to a road surface state where a vehicle travels and a steering state.

  The vehicle motion control apparatus according to the present invention includes braking means (MBR) and control means (CTL). The braking means (MBR) applies a braking torque to the vehicle wheel (WH [**]). The control means (CTL) increases the braking torque (Pwt [**], Pwa [**]) through the braking means (MBR) and executes braking control for improving the stability of the vehicle. . Hereinafter, braking control that improves vehicle stability by increasing braking torque is simply referred to as “braking control”.

  Further, the vehicle motion control device includes a steering amount acquisition unit (SAA) and a turning amount acquisition unit (TCA). The steering amount acquisition means (SAA) acquires the steering amount (Saa) of the steering operation member (SW). The turning amount acquisition means (TCA) acquires a turning amount (Tca) representing the degree of turning state of the vehicle. The control means (CTL) increases the braking torque (Pwt [**], Pwa [**]) when the turning amount (Tca) exceeds a reference amount (Trf). 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), and determines the transient steering state (Kat = 1). ) To change the reference amount (Trf) to a small value.

  In other words, there are two reference amounts (Trf1, Trf2) having different magnitudes as the reference amount (Trf), which is a threshold value for executing the braking control, and the transient steering state is not determined. The larger one of the two reference quantities (first reference quantity Trf1) is set as the reference quantity (Trf), and when the transient steering state is determined, the smaller one of the two reference quantities ( The second reference amount Trf2) is set as the reference amount (Trf).

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

  When transient steering is performed in which the operation amount of the steering operation member continuously increases or decreases, the stability of the vehicle is likely to be impaired. In particular, this sign becomes prominent when the road surface friction coefficient is low. It is determined whether or not the steering state is a transient steering state, and a reference amount that is a control threshold value corresponding to the turning amount is determined, so that appropriate braking control according to the steering state can be performed. When the transient steering state is determined, the reference amount is changed to a small value, so that the braking torque is increased earlier and the vehicle stability can be reliably maintained. Further, since the road surface state (for example, road surface friction coefficient) is reflected in the turning amount, the braking control is executed based on the comparison between the actual turning amount and the reference amount, so that the braking according to the road surface state is performed. Control can take place.

1 is a diagram illustrating an overall configuration of a vehicle including a vehicle motion control device according to an embodiment of the present invention. It is a figure which shows the whole structure of the brake actuator BRK. 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 arithmetic processing of the vehicle motion control apparatus in this embodiment. It is a functional block diagram which shows the example of a calculation process in the braking control calculation block CTL. It is a time series diagram for demonstrating the effect | action and effect of the vehicle motion control apparatus which concerns on embodiment of this invention.

  FIG. 1 is a diagram illustrating an overall configuration of a vehicle including a vehicle motion control apparatus 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.

  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 transmission system electronic control unit ECUa, control of the gear ratio of the automatic transmission AT is executed.

  The brake actuator BRK (corresponding to a part of the braking means MBR) has a 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 fluid pressure for each wheel cylinder WC [**] independently of the operation of the brake pedal BP, and adjust the brake torque for each wheel.

  Each wheel is provided with a known wheel cylinder WC [**], brake caliper BC [**], brake pad PD [**], and brake rotor RT [**] as braking means MBR. 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, a braking torque is applied to each wheel. Note that the control of the braking torque is not limited to that based on the braking hydraulic pressure, and can be performed using an electric brake device.

  FIG. 2 is a diagram showing an overall configuration of the brake actuator BRK. When the driver depresses a braking operation member (for example, a brake pedal) BP, the pedaling force is boosted by the booster VB, and the master piston provided in the master cylinder MC is pushed. As a result, the same master cylinder pressure Pmc is generated in the first chamber and the second chamber defined by the master piston. Master cylinder pressure Pmc is applied to wheel cylinder WC [**] of each wheel WH [**] through brake actuator BRK.

  The brake actuator BRK has a first piping system HP1 connected to the first chamber of the master cylinder MC and a second piping system HP2 connected to the second chamber of the master cylinder MC. The first piping system HP1 controls the brake fluid pressure applied to the left front wheel WH [fh] and the right rear wheel WH [rm]. The second piping system HP2 controls the brake fluid pressure applied to the right front wheel WH [fm] and the left rear wheel WH [rh]. Since the first piping system HP1 and the second piping system HP2 have the same configuration, only the first piping system HP1 will be described below, and the description of the second piping system HP2 will be omitted. The configuration shown in FIG. 2 is a diagonal piping configuration, but the brake piping configuration may be front and rear piping.

  The first piping system HP1 includes a pipe line LA that generates braking hydraulic pressures (hydraulic pressures in the wheel cylinders) Pw [fh] and Pw [rm]. The pipe line LA is provided with a first differential pressure control valve SS1 that can be controlled between a communication state and a differential pressure state. Then, the master cylinder pressure Pmc is transmitted to the wheel cylinder WC [fh] provided in the left front wheel WH [fh] and the wheel cylinder WC [rm] provided in the right rear wheel WH [rm]. During normal braking in which the driver operates the brake pedal BP (when brake control is not being executed), the valve position of the first differential pressure control valve SS1 is adjusted to an open state so as to be in a communicating state. . When the first differential pressure control valve SS1 is energized, the valve position is adjusted to the closed state, and the first differential pressure control valve SS1 is set to the differential pressure state.

  The pipe line LA branches into two pipe lines LA [fh] and LA [rm] on the side of the wheel cylinders WC [fh] and WC [rm] from the first differential pressure control valve SS1. The line LA [fh] is provided with a first pressure increase control valve SZ [fh] that controls the increase of the brake fluid pressure to the wheel cylinder WC [fh]. The pipe line LA [rm] is provided with a second pressure increase control valve SZ [rm] for controlling the increase of the brake fluid pressure to the wheel cylinder WC [rm]. The first and second pressure-increasing control valves SZ [fh] and SZ [rm] are constituted by two-position electromagnetic valves that can control the communication / blocking state. The first and second pressure increase control valves SZ [fh] and SZ [rm] are in a communication state (open state) when the supplied current is “0” (when not energized), and the current flows. Is controlled to be in a shut-off state (closed state). The first and second pressure increase control valves SZ [fh], SZ [rm] are so-called normally open types.

  The pipe line LB is a pressure reducing unit that connects the first and second pressure increase control valves SZ [fh], SZ [rm] and the wheel cylinders WC [fh], WC [rm] and the pressure regulating reservoir R1. It is a pipe line for. The pipe LB is provided with a first pressure reduction control valve SG [fh] and a second pressure reduction control valve SG [rm] configured by two-position electromagnetic valves capable of controlling the communication / blocking state. The first and second pressure reduction control valves SG [fh] and SG [rm] are closed when not energized and opened when energized. These are so-called normally closed types.

  A pipeline LC is disposed between the pressure regulating reservoir R1 and the pipeline LA. A hydraulic pump OP1 is provided in the pipeline LC. The brake fluid is sucked from the pressure adjusting reservoir R1 by the hydraulic pump OP1, and is discharged toward the master cylinder MC or the wheel cylinders WC [fh] and WC [rm]. The hydraulic pump OP1 is driven by an electric motor MT. A pipe line LD is provided between the pressure regulating reservoir R1 and the master cylinder MC. When automatic pressurization such as vehicle stability control or traction control is performed, brake fluid is sucked from the master cylinder MC through the line LD by the hydraulic pump OP1 and discharged to the lines LA [fh] and LA [rm]. The As a result, the brake fluid is supplied to the wheel cylinders WC [fh] and WC [rm], the brake fluid pressure of the wheel cylinder WC [**] of the target wheel is increased, and braking torque is applied.

  First, with reference to FIG. 3, a steering operation when an obstacle is urgently avoided will be described.

  FIG. 3A 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. 3B 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, when the first steering is performed relatively slowly after the first steering is performed as indicated by the broken line in FIG. 3B, the second steering is not performed (that is, the transient steering is not 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. 4 is a functional block diagram showing an example of arithmetic processing of the vehicle motion control apparatus in 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. In addition, the braking control that increases the braking torque based on the turning amount Tca or the like to ensure vehicle stability is simply referred to as braking control.

  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 vehicle driver is acquired. 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 a steering speed acquisition calculation block (corresponding to a steering speed acquisition means) DSA, a steering speed (for example, steering angular speed) dSa that is an operation speed of the steering operation member SW operated by the driver of the vehicle is acquired. The steering speed dSa can be calculated based on the steering amount Saa by time differentiation.

  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. As the turning amount Tca, a value corresponding to the lateral acceleration of the vehicle (a value corresponding to the lateral acceleration) can be calculated. The lateral acceleration equivalent value reflects the influence of the road surface friction coefficient. By using the lateral acceleration equivalent value, braking control according to the road surface condition can be performed. Specifically, the lateral acceleration (actual lateral acceleration) Gya detected by the lateral acceleration sensor GY is acquired as the turning amount Tca. Further, based on the yaw rate Yra detected by the yaw rate sensor YR (by multiplying the yaw rate Yra by the vehicle speed Vxa), the calculated lateral acceleration Gye can be calculated as the turning amount Tca. Here, the vehicle speed Vxa can be calculated based on the detection result (wheel speed Vwa [**]) of the wheel speed acquisition means VWA (for example, the 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.

  The steering amount Saa, the steering speed dSa, the turning amount Tca (for example, the lateral acceleration Gya, the yaw rate Yra), the vehicle speed Vxa, the wheel speed Vwa [**], and the braking operation amount Bsa are obtained via the communication bus CB. It can be calculated based on sensor values and / or internal calculated values in other systems.

  In the braking control calculation block (corresponding to the control means) CTL, the target braking torque Pwt [**] of each wheel is calculated based on the steering speed dSa, the turning amount Tca, and the steering amount Saa. The braking control calculation block CTL includes a transient steering determination calculation block (transient steering determination means) KAT, a reference amount calculation block (reference amount setting means) TRF, and a target control torque calculation block (target braking torque determination means) PWT. The In the transient steering determination calculation block KAT, it is determined that the steering state of the vehicle is a transient steering state based on the steering amount Saa. That is, one of the first state in which the transient steering state is not determined and the second state in which the transient steering state is determined is selected. In the reference amount calculation block TRF, a reference amount Trf (Trf1, Trf2), which is a brake control execution condition (for example, a control threshold value for starting an increase in braking torque), is set based on the steering state and the steering speed dSa of the vehicle. Is done. Here, the reference amount Trf is set to the first reference amount Trf1 as an initial value. The first reference amount Trf1 is a reference amount Trf that is calculated when the steering state is not transient steering (when the transient steering state is not determined). When the transient steering state is determined, the reference amount Trf is changed to the second reference amount Trf2. The second reference amount Trf2 is a value smaller than the first reference amount Trf1. In the target control torque calculation block PWT, the target value Pwt [**] of the braking torque of each wheel is calculated based on the reference amount Trf (Trf1 or Trf2) and the turning amount Tca.

  In the transient steering determination calculation block KAT, it is determined whether or not the vehicle is in the transient steering state based on the steering amount Saa. Here, the transient steering state is a state of a steering operation that fluctuates when transitioning from a certain steady steering state (a state where the steering amount is substantially constant) to another steady steering state, and an increase in the steering amount, and This is a steering state in which the decrease is continuously performed. In the transient steering discrimination calculation block KAT, a first state (non-transient steering state) in which the transient steering state is not discriminated is set as an initial state. Then, the second state that is the transient steering state is determined based on the steering amount Saa.

  Since the steering direction continuously changes in the transient steering state, the transient steering state is determined based on the steering direction Dstr identified based on the steering amount Saa. First, it is determined whether 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 other of the left direction and the right direction is different from the one direction). Is done. When the steering direction Dstr is determined to be one direction (for example, the left direction), the first state (initial state) that is the non-transient steering state is determined. When the steering direction Dstr is determined to be one direction (for example, left direction) and then continuously (within a predetermined time tka0), it is determined to be the other direction (for example, right direction) A second state that is a steering state is determined.

  Since the steering amount of the steering operation member SW continuously increases / decreases in the transient steering state, the transient steering state is determined based on the steering amount Saa. After the steering amount Saa is within a predetermined range (within ± saa1 (predetermined value)) (a state in which the steering amount Saa maintains a substantially constant value) for a predetermined time tsa1 or more, the steering amount Saa Is increased, it is determined as a first state (initial state) which is a non-transient steering state. Then, immediately after the steering amount Saa is increased, it can be determined that the steering state Saa continuously decreases (within the predetermined time tka1) when the steering amount Saa is the second state which is a transient steering state.

  Further, the transient state can be determined based on the sign of the steering speed dSa. That is, when the steering speed dSa has a positive sign (+), the steering amount Saa increases, and when the steering speed dSa has a negative sign (−), the steering amount Saa decreases. For example, in the case where the sign of the steering speed dSa is a positive sign after the magnitude (absolute value) of the steering speed dSa has remained substantially zero (less than the predetermined speed dsa0) for a predetermined time (predetermined value) tsa2 or more. A first state (initial state) that is a non-transient steering state is determined. Then, immediately after the sign of the steering speed dSa becomes a positive sign, when the sign of the steering speed dSa changes to a negative sign continuously (within less than the predetermined time tka2), the second state is a transient steering state. Can be discriminated.

  In the transient steering determination calculation block KAT, the transient steering state is determined based on at least one of the steering amount (operation amount of the steering operation member) Saa and the steering speed (operation speed of the steering operation member) dSa. When the transient steering determination block KAT does not determine the transient steering state, “0 (initial value)” is output as the control flag (signal indicating the determination result in the calculation process) Kat indicating the first state. When the transient steering state is determined, the control flag Kat is switched from “0 (first state)” to “1 (second state)”.

  In the reference amount calculation block TRF, a reference amount Trf, which is a condition for executing braking control (for example, a condition for starting an increase in braking torque), is set. When the transient steering state is not determined, the first reference amount Trf1 is calculated based on the steering speed dSa and set as the reference amount Trf. The first reference amount Trf1 is set to a smaller value as the degree (size) of the steering speed dSa increases. When the transient steering state is determined, the second reference amount Trf2 having a value smaller than the first reference amount Trf1 is calculated, and the second reference amount Trf2 is set as the reference amount Trf. That is, the reference amount Trf is changed from the first reference amount Trf1 to the second reference amount Trf2 (<Trf1). The second reference amount Trf2 is set to a smaller value as the degree (size) of the steering speed dSa increases. Further, the second reference amount Trf2 can be set to a value smaller than the first reference amount Trf1 by a predetermined amount trf0. The reference amount calculation block TRF outputs the first reference amount Trf1 when Kat = 0 (when not discriminating transient steering), and the second reference amount when Kat = 1 (when determining transient steering). Trf2 is output.

  In the target control torque calculation block PWT, the target braking torque Pwt [**] for increasing the braking torque of each wheel is calculated based on the reference amount Trf (Trf1 or Trf2) and the turning amount Tca. Specifically, when the turning amount Tca is equal to or less than the reference amount Trf, the target braking torque Pwt [**] is not increased and is maintained. When the turning amount Tca exceeds the reference amount Trf, the braking torque Pwt [**] is increased. The target braking torque Pwt [**] can be determined based on a comparison result between the turning amount Tca and the reference amount Trf.

  In the target control torque calculation block PWT, when the braking operation amount Bsa acquired by the braking operation amount acquisition calculation block BSA is equal to or less than the predetermined operation amount (predetermined value) bsa1, the braking torque Pwt [ **] increase allowed. On the other hand, when the braking operation amount Bsa is larger than the predetermined operation amount bsa1, the increase in the braking torque Pwt [**] is invalidated (Pwt [**] = 0) and is held in the state before the start of the braking control. The When the driver is performing a braking operation, the braking torque has already been applied to the wheels, so that it is not necessary to increase the braking torque. Since the braking torque increase is performed only when the amount of braking operation is equal to or less than the predetermined value bsa1 (for example, when bsa1 = 0 and no braking operation is performed), an unnecessary increase in braking torque can be suppressed.

  In the target control torque calculation block PWT, an increase in the target braking torque Pwt [f *] for the front wheels is permitted, and the target braking torque Pwt [r *] for the rear wheels can be invalidated (Pwt [r *] = 0). That is, the braking torque of the front wheels is increased, and the braking torque of the rear wheels is not increased (the braking torque before the braking control is executed is held). The front wheel lateral force is reduced by the increase of the braking torque of the front wheels, and the rear wheel braking torque is not increased (maintained) and the rear wheel lateral force is secured, so that the yawing stability of the vehicle can be secured.

  Based on the target braking torque Pwt [**], the braking means MBR controls the driving means of the brake actuator BRK (for example, the electric motor for driving the hydraulic pump, the driving means for the solenoid valve), and the braking torque of the wheel Is increased. When the driver is operating the braking operation member BP, the braking torque by the 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 the braking control.

  A sensor (for example, a pressure sensor PW [**]) that detects an actual value Pwa [**] of the braking torque corresponding to the target value Pwt [**] of the braking torque may be provided on the wheel. Based on the target value Pwt [**] and the actual value Pwa [**], the driving means can be controlled so that the actual value Pwa [**] matches the target value Pwt [**].

  In the reference amount calculation block TRF, the reference amount Trf (Trf1, Trf2) is set based on the steering speed dSa, but the steering speed peak value storage calculation block (stores) that stores the steering speed peak value (peak steering speed) dSap. (Corresponding to means) DSAP is provided, and the reference amount Trf can be set 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. In the reference amount calculation block TRF, the first reference amount Trf1 is set based on the peak steering speed dSap as described above. In other words, the first reference amount Trf1 is set to a smaller value as the degree (size) of the peak steering speed dSap is larger. 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. 5, the details of an example of the calculation process in the braking control calculation block CTL will be described.

  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 first state (transient steering non-discrimination state) in which the transient steering state is not discriminated is set as an initial state. Then, a second state (transitional steering determination state) in which the transient steering state is determined based on the steering amount Saa is determined.

  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. That is, one of the first state and the second state is selected. 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, it is calculated as the other direction, 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. In the steering state determination block KTI, the first state (Kat = 0) is set as the initial state of the determination result. Further, when the steering direction Dstr is a straight traveling direction, the first state (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. Is done.

  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. That is, one of the first state and the second state is selected. The determination result is output as a control flag Kat. As a determination result, the first state (Kat = 0) is set 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 based on the steering direction Dstr) is less than the 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, the first state (Kat = 0) is determined. The second state (Kat = 1) is determined when the steering amount Saa continuously decreases after the steering amount Saa has increased. 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), the first state (Kat = 0) is determined. When the steering speed dSa is equal to or higher than the predetermined speed dsa0 (positive steering), the second state (when the steering speed dSa is continuously equal to or lower than the predetermined speed -dsa0 and is negative (switchback steering)). Kat = 1) is determined. 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 the transient steering state is not determined (Kat = 0), as indicated by the characteristic Chc1, when the steering speed dSa is less than a predetermined speed (predetermined value) ds1, the first reference amount Trf1 becomes a predetermined amount (predetermined value) tr1. When the steering speed dSa is greater than or equal to the predetermined speed ds1 and less than the predetermined speed (predetermined value) ds2, the first reference amount Trf1 is calculated to decrease as the steering speed dSa increases, and the steering speed dSa is determined to be the predetermined speed ds2. At the above time, the first reference amount Trf1 is calculated as a predetermined amount (predetermined value) tr2. When the transient steering state is determined (Kat = 1), instead of the first reference amount Trf1, the second reference is obtained when the steering speed dSa is less than the predetermined speed ds1, as indicated by a characteristic Chc2 smaller than the characteristic Chc1. The amount Trf2 is calculated to be a predetermined amount (predetermined value) tr3 (<tr1), and 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 decreases as the steering speed dSa increases. When the steering speed dSa is equal to or higher than the predetermined speed ds2, the second reference amount Trf2 is calculated to be a predetermined amount (predetermined value) tr4 (<tr2). The second reference amount Trf2 (reference amount Trf in the second state) can always be calculated to be smaller than the first reference amount Trf1 (reference amount Trf in the first state) regardless of the value of the steering speed dSa. From the reference amount calculation block TRF, when Kat = 0, the first reference amount Trf1 is output to the target control torque calculation block PWT, and when Kat = 1, the second reference amount Trf2 is output to the target control torque calculation block PWT. 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 control torque calculation block PWT, the target braking torque Pwt [**] is calculated based on the turning amount Tca and the reference amount Trf (Trf1, Trf2). When Kat = 0 (when transient steering is not determined), the turning amount Tca is compared with the first reference amount Trf1. When the turning amount Tca is equal to or less than the first reference amount Trf1, the target braking torque Pwt [**] is calculated as “0”, and the target braking torque Pwt [**] is not increased. When the turning amount Tca exceeds the first reference amount Trf1, the target braking torque Pwt [**] increases as the deviation ΔTc (= Tca−Trf1) between the turning amount Tca and the first reference amount Trf1 increases. Is calculated. When Kat = 1 (when determining the transient steering), the turning amount Tca is compared with the second reference amount Trf2. When the turning amount Tca is equal to or smaller than the second reference amount Trf2, the target braking torque Pwt [**] is calculated as “0”, and the target braking torque Pwt [**] is not increased. When the turning amount Tca exceeds the second reference amount Trf2, the target braking torque Pwt [**] increases as the deviation ΔTc (= Tca−Trf2) between the turning amount Tca and the second reference amount Trf2 increases. Is calculated. An upper limit value pw1 can be set for the target braking torque Pwt [**].

  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. 3A, 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.

  FIG. 6 is a time-series diagram for explaining the operation and effect of the vehicle motion control apparatus according to the embodiment of the present invention. Three cases (Tca1, Tca2, Tca3) are shown according to the change state of the turning amount (state amount representing the degree of turning motion of the vehicle) Tca.

  Until the time (time point) t0 is reached, the steering operation is not performed, the turning amount Tca1 and the like are “0 (straight traveling)”, the control flag Kat is set to “0 (first state)” as an initial value, and braking is performed. A first reference amount Trf1, which is a threshold value (reference amount Trf) of an execution condition (for example, start condition) of control (an increase in braking torque), is calculated to a 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 turning amount Tca (turning amount Tca1) is generated corresponding to the steering operation will be described. When the turning amount Tca1 is equal to or less than the reference amount Trf, the braking control is not executed. At the time t2 when the turning amount Tca1 exceeds the reference amount Trf (the first reference amount Trf1 because it is in the first state), the execution of the braking control is started and the braking torque is increased. At this time, the increase amount Pwt [**] of the braking torque is calculated based on a deviation ΔTc (= Tca1−Trf1) between the turning amount Tca1 and the reference amount Trf (first reference amount Trf1). 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 turning amount Tca 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 in the first state in which the transient steering state is not discriminated, the braking torque is increased based on the comparison result between the reference amount Trf and the turning amount Tca determined according to the steering speed dSa. Movement can also be stabilized.

  Next, a case where a transient steering operation is performed will be described, although the generated turning amount Tca (turning amount Tca2) is relatively small. The transient steering state is determined at time t1, and the reference amount Trf is changed to a relatively small value as compared to when the transient steering is not determined (first state). That is, the reference amount Trf is changed from the first reference amount Trf1 to the second reference amount Trf2 (<Trf2). When the turning amount Tca2 is equal to or less than the reference amount Trf, the braking control is not performed. At time t3 when the turning amount Tca2 exceeds the reference amount Trf (second reference amount Trf2 because it is in the second state), execution of the braking control is started and the braking torque is increased. At this time, the increase amount Pwt [**] of the braking torque is calculated based on a deviation ΔTc (= Tca2−Trf2) between the turning amount Tca2 and the reference amount Trf (second reference amount Trf2). 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 the stability of the vehicle (particularly yawing stability) is reliably maintained. obtain. Furthermore, since the transient steering state is not discriminated at the time of the additional steering of the first steering, early braking torque increase can be suppressed, and the turning ability of the vehicle (followability of the turning behavior with respect to the steering operation) can be ensured.

  Further, an intermediate turning amount Tca (turning amount Tca3) between the turning amount Tca1 (relatively large) and the turning amount Tca2 (relatively small) may occur. 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 turning amount Tca3 exceeds the reference amount Trf (second reference amount Trf2), and the braking control is performed. Be started. Also in this case, the braking torque increase amount Pwt [**] is calculated based on the deviation ΔTc (= Tca3−Trf2) between the turning amount Tca3 and the reference amount Trf (second reference amount Trf2).

The above-described braking control (braking torque increase) may be performed only on the front wheels and not on the rear wheels. That is, when the turning amount Tca exceeds the reference amount Trf, the braking torque of the front wheels is increased and the braking torque of the rear wheels is not increased (the braking torque before the braking control is executed is held). The front wheel lateral force is reduced by the increase in the braking torque of the front wheels, and the rear wheel braking torque is not increased (maintained), so that the rear wheel lateral force is ensured and the stability of the vehicle can be maintained.
The technical idea that can be grasped from the above embodiment will be added below.
(1)
A vehicle motion control device comprising: braking means for applying braking torque to a vehicle wheel; and control means for executing braking control for increasing the braking torque through the braking means to improve the stability of the vehicle. And a steering amount acquisition unit that acquires a steering amount of the steering operation member of the vehicle, and a turning amount acquisition unit that acquires a turning amount that represents a degree of a turning state of the vehicle, and the control unit includes: When the turning amount exceeds a reference amount, the braking torque is increased, and a transient steering state in which the steering amount continuously increases or decreases is determined based on the steering amount, and the transient steering state is determined. A motion control device for a vehicle, wherein the reference amount is changed to a small value.
The vehicle motion control apparatus according to the present invention includes braking means (MBR) and control means (CTL). The braking means (MBR) applies a braking torque to the vehicle wheel (WH [**]). The control means (CTL) increases the braking torque (Pwt [**], Pwa [**]) through the braking means (MBR) and executes braking control for improving the stability of the vehicle. . Hereinafter, braking control that improves vehicle stability by increasing braking torque is simply referred to as “braking control”.
Further, the vehicle motion control device includes a steering amount acquisition unit (SAA) and a turning amount acquisition unit (TCA). The steering amount acquisition means (SAA) acquires the steering amount (Saa) of the steering operation member (SW). The turning amount acquisition means (TCA) acquires a turning amount (Tca) representing the degree of turning state of the vehicle. The control means (CTL) increases the braking torque (Pwt [**], Pwa [**]) when the turning amount (Tca) exceeds a reference amount (Trf). 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), and determines the transient steering state (Kat = 1). ) To change the reference amount (Trf) to a small value.
In other words, there are two reference amounts (Trf1, Trf2) having different magnitudes as the reference amount (Trf), which is a threshold value for executing the braking control, and the transient steering state is not determined. The larger one of the two reference quantities (first reference quantity Trf1) is set as the reference quantity (Trf), and when the transient steering state is determined, the smaller one of the two reference quantities ( The second reference amount Trf2) is set as the reference amount (Trf).
When transient steering is performed in which the operation amount of the steering operation member continuously increases or decreases, the stability of the vehicle is likely to be impaired. In particular, this sign becomes prominent when the road surface friction coefficient is low. It is determined whether or not the steering state is a transient steering state, and a reference amount that is a control threshold value corresponding to the turning amount is determined, so that appropriate braking control according to the steering state can be performed. When the transient steering state is determined, the reference amount is changed to a small value, so that the braking torque is increased earlier and the vehicle stability can be reliably maintained. Further, since the road surface state (for example, road surface friction coefficient) is reflected in the turning amount, the braking control is executed based on the comparison between the actual turning amount and the reference amount, so that the braking according to the road surface state is performed. Control can take place.
(2)
The vehicle motion control apparatus according to (1), further comprising a steering speed acquisition unit that acquires a steering speed of the steering operation member, wherein the control unit sets the reference amount based on the steering speed. A vehicle motion control device.
The vehicle motion control apparatus according to the present invention includes a steering speed acquisition means (DSA), and acquires the steering speed (dSa) of the steering operation member (SW). The control means (CTL) may be configured to set the reference amount (Trf) based on the steering speed (dSa). Specifically, the control means (CTL) sets the reference amount (Trf) to be smaller as the steering speed (dSa) is larger.
Since the reference amount is calculated based on the steering speed, in the case of sudden steering, the reference amount is set to a small value, and braking control is started earlier to ensure vehicle stability. On the other hand, in the case of gentle steering, the reference amount is set to a large value, and unnecessary braking control can be suppressed.
(3)
The vehicle motion control apparatus according to (2), comprising storage means for storing a peak value of the steering speed, wherein the control means sets the reference amount based on the peak value. A vehicle motion control device.
The vehicle motion control apparatus according to the present invention includes storage means (DSAP) and stores a peak value (dSap) of the steering speed (dSa). The control means (CTL) may be configured to set the reference amount (Trf) based on the peak value (dSap). Specifically, the control means (CTL) sets the reference amount (Trf) to be smaller as the peak value (dSap) is larger.
There is a phase difference between the steering operation and the turning motion generated as a result of the steering operation. Since the peak value of the steering speed is used for setting the reference amount, this phase difference is compensated, and reliable vehicle motion control can be executed.
(4)
In the vehicle motion control device according to any one of (1) to (3), the turning amount acquisition means acquires a lateral acceleration equivalent value corresponding to the lateral acceleration of the vehicle as the turning amount. Motion control device.
The turning amount (Tca) is preferably obtained as a lateral acceleration equivalent value (Gya, Gye) corresponding to the lateral acceleration of the vehicle.
The value corresponding to the lateral acceleration (the value corresponding to the lateral acceleration) reflects the influence of the road surface friction coefficient, but since the turning amount is acquired (calculated) as the value corresponding to the lateral acceleration, braking according to the road surface friction coefficient is performed. Control can take place.
(5)
In the vehicle motion control apparatus described in (1) to (4), the control means determines whether the steering direction of the vehicle is one direction or the other direction based on the steering amount, and A vehicle motion control apparatus, wherein the transient steering state is determined when it is determined that the direction is the other direction continuously after it is determined that the direction is one direction.
In the vehicle motion control apparatus according to the present invention, the control means (CTL) determines, based on the steering amount (Saa), whether the steering direction of the vehicle is one direction or the other direction, The transient steering state may be determined when it is determined that the direction is the other direction continuously after it is determined that the direction is the one direction.
After a steering operation (first steering) is performed in one direction, vehicle stability is likely to be impaired when a steering operation (second steering) is performed in which the steering direction is continuously switched in the other direction. Since the transient steering state is determined when the first steering is immediately shifted to the second steering based on the steering direction, the vehicle stability can be reliably maintained.
(6)
In the vehicle motion control device according to any one of (1) to (5), the control means determines the transient steering state when the steering amount decreases continuously after increasing. Motion control device.
The control means (CTL) may be configured to determine the transient steering state when the steering amount (Saa) continuously decreases after increasing.
After the additional steering (steering operation in the direction away from the neutral position (Saa = 0)) is performed, the sudden return steering (steering operation in the direction approaching the neutral position (Saa = 0)) is continuously performed. In such a case, there is a high probability that transient steering is performed. Since the transient steering state is determined based on the steering amount when the switchback steering is started, the braking torque is applied early, and the vehicle stability can be reliably maintained.
(7)
The vehicle motion control apparatus according to any one of (1) to (6), further comprising: a braking operation amount acquisition unit that acquires a braking operation amount of a braking operation member operated by a driver of the vehicle; The vehicle motion is characterized in that the braking torque is increased when the braking operation amount is less than or equal to a predetermined operation amount, and the braking torque is maintained when the braking operation amount is larger than the predetermined operation amount. Control device.
The vehicle motion 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 braking torque (Pwt [**], Pwa [**]) when the braking operation amount (Bsa) is equal to or less than a predetermined operation amount (predetermined value bsa1), In addition, the brake torque (Pwt [**], Pwa [**]) may be held when the brake operation amount (Bsa) is larger than the predetermined operation amount (bsa1).
When the driver is performing a braking operation, braking torque is already applied to the wheels, so braking control is not necessary. Since the braking torque is increased only when the braking operation amount is equal to or less than the predetermined operation amount bsa1 (for example, when bsa1 = 0 and no braking operation is performed), an unnecessary increase in braking torque can be suppressed. .

  TCA: turning amount acquisition means, Tca: turning amount, TRF: reference amount setting means (reference amount calculation), Trf: reference amount, SAA: steering amount acquisition means, Saa: steering amount, DSA: steering speed acquisition means, dSa ... Steering speed, CTL ... control means (brake control means), MBR ... brake means, BRK ... brake actuator, KAT ... transient steering discrimination means (transient steering discrimination calculation), PWT ... target braking torque determination means (target braking torque calculation)

Claims (1)

Braking means for applying braking torque to the wheels of the vehicle;
A vehicle motion control device comprising: control means for executing braking control for increasing the braking torque via the braking means to improve the stability of the vehicle,
Steering amount acquisition means for acquiring the steering amount of the steering operation member of the vehicle;
A turning amount acquisition means for acquiring a turning amount representing the degree of the turning state of the vehicle,
The control means includes
Increasing the braking torque when the turning amount exceeds a reference amount;
Small said criterion values when the transient steering state where the steering amount is increased or decreased continuously to determine if the steering amount is decreased continuously after increase based on the steering amount, and determines the transient steering state A motion control apparatus for a vehicle, characterized in that the value is changed to a value.

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