JP2010064719A - Motion control device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motion control device for a vehicle, which can predict a generation of rapid yawing behavior based on steering operation to enhance the responsiveness of a braking liquid pressure in vehicle stability control. <P>SOLUTION: In the vehicle motion control device for executing vehicle stability control for suppressing the over-steering of the vehicle, the rapid yawing behavior of the vehicle is predicted based on the steering angle, and pre-load control for giving pre-load to a braking means of an appropriate wheel is executed. The steering angle is detected with a steering angle sensor and a steering angular speed is operated based on the detected steering angle. The turn-back state of steering is determined when the steering angle is increased, and when the steering angular speed at the turn-back steering state is large, the pre-load control for giving pre-load to the braking means is executed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle motion control device that maintains the stability of a vehicle by controlling the brake fluid pressure in the brake device.

As a conventional vehicle motion control device, for example, there is one disclosed in Patent Document 1. This motion control device improves the response of the brake fluid pressure when performing vehicle stability control, and eliminates the need for the frequency of operation of the pressure source (pump, motor) and pressure regulating valve means used for vehicle stability control. In order to suppress the increase, it is highly likely that the brake control is executed next in the combination of the current braking control execution wheel and the change (increase / decrease) tendency of the yaw rate deviation during the control of the vehicle stability control. It is described that a wheel is predicted and preload control is performed using the wheel as a target wheel.
JP 11-227586 A

  However, in the vehicle motion control device described in Patent Document 1 described above, the preload of the brake fluid pressure is the difference between the yaw rate deviation (the calculated target yaw rate and the detected actual yaw rate) during the control of the vehicle stability control. Deviation). That is, the preload control of the brake fluid pressure is executed after the yawing behavior to the extent that the vehicle stability control is started occurs in the vehicle. In order to further improve the responsiveness of the brake fluid pressure, even if a yawing behavior that does not start the vehicle stability control is identified, the start of the vehicle stability control is predicted and the preload control is performed. Is required.

  By the way, the scene where the response of the brake fluid pressure is required in the vehicle stability control will be described. A highly responsive braking fluid pressure is required when a fast (rapid) yawing behavior occurs (for example, when the yaw rate or the vehicle skid angular velocity is very high). Normally, the steering characteristic of a vehicle is set to weak understeer according to vehicle specifications, suspension settings, and the like. Therefore, in a steering operation that gradually turns the steering wheel (a steering operation that generates a steady turning state of the vehicle), the vehicle becomes understeer and reaches the turning limit. Therefore, a highly responsive braking fluid pressure characteristic is not required.

  On the other hand, in a steering operation that urgently avoids an obstacle or the like, a fast yawing behavior occurs, so that a high response of braking fluid pressure is required. Here, the emergency avoidance steering operation refers to a steering operation (e.g., moving the vehicle laterally from the currently traveling line to avoid an obstacle, and then returning the vehicle to the original traveling line ( Steering operation for generating a transient turning state of the vehicle), and is called, for example, a double lane change.

  The emergency avoidance steering operation will be described with reference to FIG. In FIG. 15, as the turning direction, the positive sign (+) is the left turning direction, and the negative sign (−) is the right turning direction. In the following, when explaining the magnitude relation (size comparison, increase / decrease) of the state quantity such as the steering angle and the turning state quantity, it is expressed by the magnitude relation of the absolute value of the state quantity in order to avoid complicated explanation. . FIG. 15 shows the steering operation when moving leftward to avoid an obstacle, return to the original travel line, and then move rightward to avoid the next obstacle. ing.

  First, in order to turn the vehicle in the left direction, the driver cuts the steering wheel in the left turning direction (counterclockwise direction when viewed from the driver). Accordingly, the steering angle Sa increases from the steering neutral position “0 (represents straight traveling of the vehicle)” to the left turning direction (positive sign direction) (the steering operation from the point a1 to the point a2 in the figure, (Also referred to as 1 steering cut). Then, the steering wheel is turned back so that the vehicle can pass while avoiding obstacles, and the steering angle Sa decreases accordingly toward the steering neutral position “0” (the steering operation from the point a2 to the point a3 in the figure, Also referred to as a one-steering turning-back state). Further, in order to return to the original travel line (in order to move the vehicle to the right), the driver cuts the steering wheel in the right turn direction (clockwise as viewed from the driver), and accordingly the steering angle Sa Increases from the steering neutral position “0 (means straight traveling of the vehicle)” to the right turning direction (the direction of the negative sign) (the steering operation from the point a3 to the point a4 in the figure, and the second steering cut) Also called state). Then, in order to make the vehicle travel in a straight line stably in the original travel line, the steering wheel is turned back and the third steering is performed.

  In the steering operation in which the turning direction changes from one direction to the other as described above, the steering operation in one direction is the first steering, the steering operation in the other direction different from the one direction is the second steering, and the subsequent operation. A steering operation in which the steering direction changes is referred to as third steering. A state in which the steering angle Sa (absolute value) increases is referred to as turning steering (steering turning state), and a state in which the steering angle Sa (absolute value) decreases is referred to as turning steering (steering turning state).

  The vehicle stability when the above steering operation is performed will be described. In a vehicle using steering wheels as front wheels, first, a slip angle is generated in the front wheels by the steering wheel operation, thereby generating a lateral force in the front wheel tires. By this front wheel lateral force, a yawing moment acts on the vehicle, and the turning motion of the vehicle is started. As a result of this turning motion, a slip angle is also generated for the rear wheel, and the rear tire begins to generate lateral force. The lateral force of the rear wheel reduces the yawing moment, and finally the front wheel lateral force and the rear wheel lateral force are balanced, and the vehicle performs a steady turning motion.

  However, when the steering operation in which the turning direction is reversed (change from one direction to the other direction) as described above is repeated, the time delay (phase difference) in the generation of the rear wheel lateral force with respect to the front wheel lateral force is generated. Increases, and an excessive yawing moment is generated with respect to the vehicle. Furthermore, since the rear tire reaches the lateral force limit (the state where the lateral force is already saturated and does not increase even if the slip angle increases), a rapid yawing behavior may occur.

  In view of the above points, the present invention provides a vehicle motion control device capable of predicting the occurrence of a sudden yawing behavior based on a steering operation and improving the response of braking hydraulic pressure in vehicle stability control. The purpose is to do.

  The vehicle motion control apparatus according to the present invention includes a braking means provided on a vehicle wheel, an actual turning amount acquisition means for acquiring an actual turning state amount of the vehicle, and the actual turning state amount based on the actual turning state amount. Stability control means for executing stability control for applying braking fluid pressure to the braking means when vehicle oversteer is identified, steering angle acquisition means for acquiring a steering angle by the driver of the vehicle, and the steering angle Steering angular velocity calculating means for calculating the steering angular velocity based on the above, and preload applying means for applying a preload to the braking means based on the magnitude of the steering angular velocity when the steering angle decreases.

  When the steering angle decreases, that is, based on the magnitude of the steering angular velocity when the turn-back steering is performed, preload control for applying a preload is performed. Therefore, it is possible to predict a yawing behavior (oversteer behavior) that occurs abruptly, perform preload control in an appropriate situation, and improve the response of the brake fluid pressure in vehicle stability control.

  In the vehicle motion control apparatus according to the present invention, the preload applying means can apply the preload when the magnitude of the steering angular velocity is a predetermined value or more. A rapid yawing behavior occurs when fast turnback steering is performed, and appropriate preload control can be performed for this behavior.

  In the vehicle motion control apparatus according to the present invention, the preload applying means can apply the preload even when oversteer of the vehicle is not identified. Even when oversteer is not identified in the first steering, a sudden yawing behavior may occur in the second steering, and appropriate preload control can be performed for this behavior.

  In the vehicle motion control apparatus according to the present invention, the preload applying means can apply the preload to the braking means of a wheel to which the braking hydraulic pressure is not applied by the stability control. By performing the preload control on the wheel braking means that can exhibit the effect of the preload control, the amount of brake fluid (brake fluid amount) that can be generated by the brake control device (brake actuator) can be effectively utilized.

  In the vehicle motion control apparatus according to the present invention, a turning direction identifying means for identifying a turning direction of the vehicle based on the steering angle is provided, and the preload applying means is a turning direction when the steering angle is reduced. The preload can be applied to the braking means of the wheel located outside in the turning direction opposite to that of the vehicle and in front of the vehicle. The effect of the preload control can be improved by performing the preload control on the braking means for the outer front wheel that is most effective for suppressing oversteer.

  The vehicle motion control apparatus according to the present invention includes a braking operation acquisition unit that acquires an operation of the braking member of the driver, and the preload applying unit is configured to perform the braking based on an acquisition result of the braking operation acquisition unit. When it is determined that the member is being operated and the determination is affirmative, the application of the preload can be prohibited. When the preload control is unnecessary, the control is prohibited, and unnecessary operation of the braking control device can be avoided.

  In the vehicle motion control apparatus according to the present invention, the preload applying means can prohibit the application of the preload when the magnitude of the steering angular velocity when the steering angle increases is less than a predetermined value. . A rapid yawing behavior occurs when fast cutting steering is performed, but a rapid yawing behavior hardly occurs during slow cutting steering. Therefore, when the steering angle increases, that is, when the steering angular velocity when the steering steering is performed is a gentle steering operation with the magnitude of the steering angular velocity being less than a predetermined value, the operation of the preload control is prohibited, and an unnecessary braking control device is provided. Can be avoided.

  In the vehicle motion control apparatus according to the present invention, the preload applying means is configured to reduce the preload when the steering angle is less than a predetermined value when the steering angle shifts from the increasing state to the decreasing state. Granting can be prohibited. When the steering operation state changes from the turning steering to the turning steering, the steering angle is small, so that a rapid yawing behavior is unlikely to occur. Therefore, when the steering angle is smaller than a predetermined value when the steering operation shifts from the turning state to the turning back state, the preload control operation is prohibited, and unnecessary operation of the braking control device can be avoided. .

  In the vehicle motion control apparatus according to the present invention, the preload applying means has a magnitude of the actual turning state amount corresponding to the shift of the steering angle from the increasing state to the decreasing state being less than a predetermined value. Sometimes the application of the preload can be prohibited. If the magnitude of the actual turning state amount that occurs when the steering operation state transitions from turning steering to turning steering is small, a rapid yawing behavior is unlikely to occur. Therefore, when the actual turning state amount corresponding to the transition from the turning state to the turning-back state is less than a predetermined value, the preload control operation is prohibited and unnecessary operation of the brake control device is avoided. can do.

  In the vehicle motion control apparatus according to the present invention, the preload applying means ends applying the preload when a predetermined time has elapsed since the stability control means started the stability control, The preload can be set to “0”. Since the vehicle stability control is started and the brake fluid pressure is generated when a predetermined time elapses, the preload control becomes unnecessary.

  In the vehicle motion control apparatus according to the present invention, the preload applying means ends applying the preload when a predetermined time has elapsed since the stability control means started the stability control, The preload can be set to “0”. If vehicle stability control is complete | finished, preload control will become unnecessary.

  In the vehicle motion control apparatus according to the present invention, the preload applying means terminates the application of the preload when a predetermined time has elapsed from the start of applying the preload, and sets the preload to “0”. can do. The vehicle stability control may not be started even when the preload control is started. Appropriate preload control can be performed by ending preload control when a predetermined time has elapsed since the start of preload control.

  In the vehicle motion control apparatus according to the present invention, the stability control means sets a small threshold value for starting the stability control based on the magnitude of the steering angular velocity when the steering angle decreases. Can be adjusted. In addition to the preload control, the responsiveness of the brake fluid pressure can be further improved by adjusting the vehicle stability control start threshold value to be small.

  Embodiments of a vehicle motion control device according to the present invention will be described below with reference to the drawings. The subscript “zz” attached to the end of various symbols, etc. indicates that the various symbols are related to any of the four wheels, “fl” is the left front wheel, “fr” is the right front wheel, “Rl” indicates the left rear wheel, and “rr” indicates the right rear wheel. Further, there are a “left turn direction” and a “right turn direction” in the turning direction of the vehicle. The left turning direction is a positive sign (+) of a state quantity (Sa, etc.), and the right turning direction is a state. It is expressed by a minus sign (-) of the quantity (Sa etc.). In order to avoid complication, when expressing the magnitude relationship (size comparison, increase / decrease) of the value, the magnitude relationship is expressed using the absolute value (size) of the value. Moreover, since the thing with the same symbol is the same, duplicate description is omitted.

(First embodiment)
FIG. 1 shows a schematic configuration of a vehicle equipped with a vehicle motion control device (hereinafter referred to as “the present device”) according to an embodiment of the present invention.

  The apparatus includes a wheel speed sensor WSzz that detects a wheel speed Vwzz, a steering wheel rotation angle sensor SA that detects a rotation angle θsw of the steering wheel SW (from a neutral position “0” corresponding to straight traveling of the vehicle), A steering angle sensor SB that detects the steering angle δfa of the steered wheel (front wheel), a steering torque sensor ST that detects torque Tsw when the driver operates the steering wheel SW, and a yaw rate sensor that detects the yaw rate Yr of the vehicle body YR, longitudinal acceleration sensor GX that detects longitudinal acceleration Gx in the longitudinal direction of the vehicle body, lateral acceleration sensor GY that detects lateral acceleration Gy in the lateral direction of the vehicle body, and wheel cylinder pressure sensor that detects braking hydraulic pressure Pwzz of the wheel cylinder WCzz An engine that detects PWzz and the rotational speed Ne of the engine EG A rotational speed sensor NE, an acceleration operation amount sensor AS that detects an operation amount As of the driver's acceleration operation member AP, a braking operation amount sensor BS that detects an operation amount Bs of the driver's braking operation member BP, A shift position sensor HS for detecting the shift position Hs of the operation member SF and a throttle position sensor TS for detecting the opening Ts of the throttle valve of the engine are provided.

  The apparatus also includes a brake actuator BRK for controlling the brake fluid pressure, a throttle actuator TH for controlling the throttle valve, a fuel injection actuator FI for controlling fuel injection, and an automatic transmission AT for controlling the shift. ing.

  In addition, the apparatus includes an electronic control unit ECU. 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. The electronic control unit ECU is electrically connected to the above-described various actuators (such as BRK) and the above-described various sensors (such as WSzz). Each system electronic control unit (ECUb, etc.) in the electronic control unit ECU executes a dedicated control program. Various sensor signals and signals calculated in the electronic control units of each system are shared via the communication bus CB.

  Specifically, the brake system electronic control unit ECUb is a known anti-skid control (ABS control), traction control (TCS control) based on signals from the wheel speed sensor WSzz, the yaw rate sensor YR, the lateral acceleration sensor GY, and the like. Slip suppression control (braking / driving force control) is executed. Further, based on the wheel speed Vwzz of each wheel detected by the wheel speed sensor WSzz, the vehicle speed Vx is calculated by a known method. The steering system electronic control unit ECUs executes well-known electric power steering control based on a signal from the steering torque sensor ST and the like. The engine system electronic control unit ECUe executes control of the throttle actuator TH and the fuel injection actuator FI based on signals from the acceleration operation amount sensor AS and the like. The transmission system electronic control unit ECUa controls the gear ratio of the automatic transmission AT.

  The brake actuator BRK has a known configuration including a plurality of electromagnetic valves (hydraulic pressure regulating valves), a hydraulic pump, an electric motor, and the like. At the time of non-control, the brake actuator BRK supplies the brake hydraulic pressure corresponding to the operation of the brake operation member BP by the driver to the wheel cylinder WCzz of each wheel, and the brake operation member (brake pedal) BP for each wheel. A braking torque corresponding to each operation is given. During braking control such as anti-skid control (ABS control), traction control (TCS control), or vehicle stability control (ESC control) that suppresses vehicle understeer or oversteer, the brake actuator BRK operates the brake pedal BP. Independently, the braking hydraulic pressure in the wheel cylinder WCzz is controlled for each wheel WHzz, and the braking torque can be adjusted for each wheel.

  As the braking means, each wheel is provided with a known wheel cylinder WCzz, brake caliper BCzz, brake pad PDzz, and brake rotor RTzz. When brake fluid pressure is applied to the wheel cylinder WCzz provided in the brake caliper BCzz, the brake pad PDzz is pressed against the brake rotor RTzz, and braking torque is applied by the friction force.

  The brake actuator BRK will be described with reference to FIG. When the driver depresses the brake pedal (braking operation member) BP, the pedaling force is boosted by the booster VB and presses the master piston disposed in the master cylinder MC. As a result, the same master cylinder pressure Pmc is generated in the first chamber and the second chamber defined by these master pistons. Master cylinder pressure Pmc is applied to wheel cylinder WCzz of each wheel WHzz through brake actuator BRK.

  The configuration shown in FIG. 2 is a configuration called diagonal piping. 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 braking fluid pressure applied to the left front wheel WHfl and the right rear wheel WHrr, and the second piping system HP2 controls the braking fluid pressure Pwzz applied to the right front wheel WHfr and the left rear wheel WHrl. . Since the first piping system HP1 and the second piping system HP2 have the same configuration, the first piping system HP1 will be described below, and the description of the second piping system HP2 will be omitted. The brake piping configuration may be front and rear piping.

  The first piping system HP1 includes a pipeline A (main pipeline) that generates wheel cylinder pressures Pwfl and Pwrr. The pipe A is provided with a first differential pressure control valve SS1 that can be controlled to a communication state and a differential pressure state, and a master cylinder pressure Pmc is provided to the wheel cylinder WCfl provided to the left front wheel WHfl and the right rear wheel WHrr. Is transmitted to the wheel cylinder WCrr. During normal braking in which the driver operates the brake pedal BP (when braking fluid pressure control is not being executed), the valve position is opened so that the first differential pressure control valve SS1 is in a communicating state. Adjusted. When a current flows through the solenoid coil provided in the first differential pressure control valve SS1, the valve position is adjusted to the closed state, and the first differential pressure control valve SS1 enters the differential pressure state.

  The pipeline A branches into two pipelines Afl and Arr on the side of the wheel cylinders WCfl and WCrr with respect to the first differential pressure control valve SS1. The pipe line Afl is provided with a first pressure-increasing control valve SZfl that controls the increase of the brake hydraulic pressure to the wheel cylinder WCfl, and the pipe line Arr is a first controller that controls the increase of the brake hydraulic pressure to the wheel cylinder WCrr. A two pressure increase control valve SZrr is provided.

  The first and second pressure increase control valves SZfl and SZrr are constituted by two-position electromagnetic valves that can control the communication / blocking state. The first and second pressure-increasing control valves SZfl and SZrr are used when the control current to the solenoid coil provided in the first and second pressure-increasing control valves SZfl and SZrr is “0” (when not energized). The communication state (open state) is established, and the control state is controlled to the cutoff state (closed state) when a control current is supplied to the solenoid coil (when energized). The first and second pressure increase control valves SZfl and SZrr are so-called normally open types.

  The pipe B is a pressure reducing pipe that connects the first and second pressure increase control valves SZfl and SZrr and the wheel cylinders WCfl and WCrr to the pressure regulating reservoir R1. The pipe B is provided with a first pressure reduction control valve SGfl and a second pressure reduction control valve SGrr configured by two-position electromagnetic valves capable of controlling the communication / blocking state. The first and second pressure reduction control valves SGfl and SGrr are so-called normally closed types that are closed when not energized and open when energized.

  Between the pressure regulation reservoir R1 and the pipeline A (main pipeline), a pipeline C (reflux pipeline) is disposed. The pipe C is provided with a hydraulic pump OP1. The hydraulic pump OP1 sucks brake fluid from the pressure adjusting reservoir R1 and discharges the brake fluid toward the master cylinder MC or the wheel cylinders WCfl and WCrr. The hydraulic pump OP1 is driven by an electric motor MT. The drive control of the electric motor MT is performed by controlling the supply voltage by turning on / off a semiconductor switch provided in the motor relay MR.

  A conduit D is provided between the pressure regulating reservoir R1 and the master cylinder MC. At the time of motion control that requires automatic pressurization such as vehicle stability control and traction control, the hydraulic pump OP1 draws brake fluid from the master cylinder MC through the pipe D and discharges it to the pipes Afl and Arr. Brake fluid is supplied to the wheel cylinders WCfl and WCrr, and the wheel cylinder of the target wheel is pressurized.

  The brake system electronic control unit ECUb is composed of a well-known microcomputer having a CPU, ROM, RAM, IO (input / output interface), etc., and executes various arithmetic processes according to a program stored in the ROM, etc. Drives and controls solenoid valves (hydraulic pressure regulating valves), electric motors, etc. Signals and the like used for various arithmetic processes are obtained from various sensors and communication buses via the input / output interface IO.

  When preload control, which will be described later, is executed, the electric motor MT is driven (rotated), the hydraulic pumps OP1 and OP2 draw in brake fluid from the master cylinder MC, and the wheel cylinder WCzz (subscript “zz” at the end of the symbol). "Fl" indicates the left front wheel, "fr" indicates the right front wheel, "rl" indicates the left rear wheel, "rr" indicates the right rear wheel, and the same applies to the other symbols). A gap (also referred to as a pad gap) between the brake pad PDzz and the brake rotor RTzz is closed, and a preload is applied to the wheel cylinder WCzz.

  Next, vehicle motion control by this apparatus will be described with reference to the functional block diagram of FIG.

  In the target turning state amount calculation block B100, a target turning state amount (target turning state amount Jrt) of the vehicle is calculated using a known method. Here, the turning state quantity is at least one of yaw rate, vehicle body side slip angle, and vehicle body side slip angular velocity. Moreover, it is a value calculated using at least one of these state quantities. For example, the target turning state amount calculation block B100 calculates the target yaw rate Yrt as the target turning state amount Jrt based on the vehicle speed Vx and the steering wheel rotation angle θsw (or the front wheel steering angle δfa). The target turning state quantity Jrt can be calculated not as a single turning state quantity but as a relationship combining a plurality of turning state quantities. For example, as the target turning state quantity Jrt, the relationship between the target vehicle body side slip angle βt and the target vehicle body side slip angular velocity dβt is calculated.

  The actual turning state quantity acquisition unit B110 acquires the actual turning state quantity Jra corresponding to the target turning state quantity Jrt. For example, when the target turning state amount Jrt is the target yaw rate, the actual yaw rate Yr detected by the yaw rate sensor YR is acquired as the actual turning state amount Jra. Further, when the target turning state quantity Jrt is calculated based on the relationship between the target vehicle body side slip angle βt and the target vehicle body side slip angular velocity dβt, the actual vehicle body side slip occurs based on the vehicle speed Vx, the actual yaw rate Yr, and the actual lateral acceleration Gy. The relationship between the angle βa and the actual vehicle side skid angular velocity dβa is calculated.

  The oversteer identification calculation block B115 identifies the degree of oversteer of the vehicle based on the outputs from the target turning state quantity calculation block B100 and the actual turning state quantity acquisition means B110. That is, in the calculation block B115, the oversteer state quantity Jos representing the degree of oversteer is calculated based on the actual turning state quantity Jra (output of the acquisition unit B110) and the target turning state quantity Jrt (output of the calculation block B100). . For example, the deviation ΔJr (= Jra−Jrt) between the actual turning state quantity Jra and the target turning state quantity Jrt is calculated as the oversteer state quantity Jos. Further, when the turning state quantity is a vehicle body side slip angle or a vehicle body side slip angular velocity, those target values can be set to constants (for example, the target value is “0”). Therefore, the target turning state quantity Jrt can be omitted in oversteer identification.

  In a vehicle stability control calculation (oversteer suppression control calculation) block B120, a target braking amount that is a target of the brake fluid pressure control that suppresses oversteer of the vehicle is calculated. Based on the oversteer state quantity Jos, the target braking hydraulic pressure Pot of the wheel cylinder WCzz or the target slip Spt which is a target value in the front and rear slip of the wheel is calculated as the target braking amount. Based on the oversteer state quantity Jos representing the degree of oversteer of the vehicle, a target braking quantity (target braking hydraulic pressure Pot or target slip Spt) is calculated using a preset target braking quantity calculation map. The In this calculation map, when the oversteer state amount Jos is less than the threshold value Tho (predetermined value), the target braking amounts Pot and Spt are set to “0”, and when the oversteer state amount Jos is equal to or greater than the threshold value Tho The target braking amounts Pot and Spt are increased from “0” as the oversteer state amount Jos increases.

  When the turning state quantity is the vehicle body side slip angle or the vehicle body side slip angular velocity, the target value can be a constant (for example, the target value is “0”), and the target turning state quantity Jrt can be omitted. At this time, the above calculation map can be set based on the actual turning state quantity Jra. When the actual turning state amount Jra is less than the threshold value Tho (predetermined value), the target braking amounts Pot and Spt are set to “0”, and when the actual turning state amount Jra is greater than or equal to the threshold value Th, the actual turning state amount is set. The target braking amount (target braking hydraulic pressure Pot or target slip Spt) is calculated based on the actual turning state amount Jra using the calculation map of the characteristic of increasing the target braking amounts Pot and Spt from “0” as Jra increases. Calculated.

  In the calculation block B120, when oversteer is identified (when the oversteer state quantity Jos or the actual turning state quantity Jra exceeds the threshold value Tho), the target braking amounts Pot and Spt for suppressing oversteer are “0”. Is calculated based on the oversteer state quantity Jos or the actual turning state quantity Jra representing the degree of the identified oversteer.

  In the steering angle acquisition means B130, the steering angle Sa is acquired via the steering angle sensor (the steering wheel operation angle sensor SA, the front wheel steering angle sensor SB) or the communication bus CB. As the steering angle Sa, the steering wheel angle θsw or the front wheel steering angle δfa is acquired.

  In the steering angular velocity calculation block B140, the steering angular velocity dSa is calculated based on the steering angle Sa. The steering angular velocity dSa is a change amount of the steering angle Sa per time, and is calculated by differentiating the steering angle Sa with time. When the steering angle Sa is the steering wheel operating angle θsw, the steering angular velocity dSa is the steering wheel operating angular velocity dθsw, and when the steering angle Sa is the front wheel steering angle δfa, the steering wheel angular velocity dδfa.

  In the preload control calculation block B150, it is determined how much preload is applied to which wheel at which timing. The preload is applied by moving the brake fluid from the master cylinder MC into the wheel cylinder WCzz, and improves the response of the brake fluid pressure. By applying the preload, a gap (pad gap) between the brake pad PDzz and the brake rotor RTzz is reduced. Further, by applying the preload, a slight brake fluid pressure is applied in advance to the wheel cylinder WCzz before the application of the brake fluid pressure by the vehicle stability control is started.

  The preload control calculation block B150 determines the return state of the steering operation in which the steering angular velocity dSa decreases, determines the start of preload control based on the magnitude of the steering angular velocity at that time, and sets the target preload amount (target preload Ppt). Alternatively, the target fluid amount Vft) required for preload is calculated. Further, since the preload control is performed for each wheel, it is determined to which wheel the preload is applied. The preload control calculation block B150 includes a start / end calculation block B151 for determining start / end of preload control, a preload amount calculation block B152 for determining a preload amount to be applied, and a preload target wheel calculation block B153 for determining a target wheel to which preload is applied. Consists of. Details of these will be described later.

  The brake fluid pressure control means B160 is based on the target braking amount Pot (or Spt) calculated in the calculation block B120 and the target preload Ppt (or target preload fluid amount Vft) calculated in the calculation block B150. The brake fluid pressure Pwzz is applied to the brake means B170 (WCzz or the like). The brake fluid pressure control means B160 includes a brake fluid pressure calculation block B161 for determining a target brake fluid pressure for each wheel based on the target brake amount and the target preload amount, and an actual value based on the determined target brake fluid pressure. The brake fluid pressure adjusting means B162 controls the wheel cylinder pressure Pwzz.

  In the brake fluid pressure calculation block B161, when the target brake amount is the target brake fluid pressure Pot and the target preload amount is the target preload Ppt, the target brake fluid pressure is the sum of the target brake fluid pressure Pot and the target prepressure Ppt. It is calculated as (= Pot + Ppt). The brake fluid pressure adjusting means B162 includes a brake actuator BRK and its drive means (for example, an electric motor for a hydraulic pump, a drive means for an electromagnetic valve). Using the detection result Pwzz of the wheel cylinder pressure sensor PWzz, so-called feedback control is performed on the electric motor MT and the hydraulic pressure regulating valves (electromagnetic valves) SS1, SS2, SZzz, and SGzz so that Pwzz matches the target braking hydraulic pressure. . Further, the braking pressure sensor PWzz of the wheel cylinder can be omitted. In this case, the operating states of the hydraulic pump, the electric motor, the electromagnetic valve, and the like constituting the brake actuator BRK are controlled based on a preset control map.

  Further, since the preload control can be performed on the wheel to which the brake fluid pressure is not applied by the vehicle stability control, the brake fluid pressure calculation block B161 handles the target brake amount and the target preload amount by separate physical quantities. be able to. For example, the driving of the electric motor MT is started based on the target fluid amount Vft (target preload amount), and the brake fluid is moved to the wheel cylinder WCzz by applying a preload by controlling the fluid pressure adjusting valve. After the vehicle stability control start condition is satisfied and the brake fluid pressure for vehicle stability control is applied to the wheel cylinder WCzz, the electric motor MT, the fluid pressure is based on the target slip Spt (target brake amount). Control valves and the like can be controlled.

  The braking means B170 includes a wheel cylinder WCzz, a brake caliper BCzz, a brake pad PDzz, and a brake rotor RTzz. The brake pad PDzz and the brake rotor RTzz are brought into contact with each other by the braking hydraulic pressure, and braking torque is applied by the frictional force, thereby generating a braking force on the wheel WHzz. A known drum brake can be used as the braking means B170.

  The preload control calculation block B150 in FIG. 3 will be described with reference to FIG. In step F100, the vehicle speed Vx and the braking operation amount Bs are read. In step F105, the steering angle Sa (steering wheel operation angle θsw, front wheel steering angle δfa), steering angular velocity dSa (steering wheel operation angular velocity dθsw, front wheel steering angular velocity dδfa), and the actual turning state amount Jra (for example, yaw rate Yr). , Lateral acceleration Gy) is read. Further, in step F110, the control state of the vehicle stability control (whether or not the vehicle stability control has already been started, and if so, what brake fluid pressure is applied to which wheel) Is read).

  In step F112, the turning direction of the vehicle is identified based on the sign of the steering angle Sa. When the sign of the steering angle Sa is a positive sign (+), the left turn direction (counterclockwise turn direction when viewing the vehicle from above) is identified. When the sign of the steering angle Sa is a negative sign (-), the right turning direction (the clockwise turning direction when viewing the vehicle from above) is identified.

  In step F115, the steering angular velocity (also referred to as the cutting steering angular velocity) dSak of the cutting steering is calculated based on the steering angle Sa and the steering angular velocity dSa. A case where the absolute value of the steering angle Sa increases is determined as a steering operation cut-in state. The previous steering angle Sa [n−1] and the current steering angle Sa [n] in the calculation cycle are compared, and the current steering angle Sa [n] is compared with the absolute value of the previous steering angle Sa [n−1]. If the absolute value has increased, it is determined that the steering operation has been cut. Here, [n-1] at the end of the symbol represents the previous value, [n] represents the current value, and so on. Then, the absolute value of the steering angular velocity dSa when the cutting state is determined is calculated as the cutting steering angular velocity dSak. That is, the steering angular velocity dSak in the cutting state is a value representing the magnitude of the steering angular velocity dSa when the driver performs the cutting steering operation.

  In step F120, the steering angular velocity (also referred to as the switching steering angular velocity) dSam of the return steering is calculated based on the steering angle Sa and the steering angular velocity dSa. When the absolute value of the steering angle Sa decreases, it is determined that the steering operation is switched back. The previous steering angle Sa [n−1] and the current steering angle Sa [n] in the calculation cycle are compared, and the current steering angle Sa [n] is compared with the absolute value of the previous steering angle Sa [n−1]. If the absolute value has decreased, it is determined that the steering operation has been switched back. Then, the absolute value of the steering angular velocity dSa when the turning-back state is determined is calculated as the turning-back steering angular velocity dSam. That is, the steering angular velocity dSam in the turning-back state is a value representing the magnitude of the steering angular velocity dSa when the driver performs the turning-back steering operation.

  In step F125, a turning state quantity (also referred to as a turning state quantity during transition) Jrm corresponding to a steering transition or a steering angle (also referred to as a transition steering angle) Sam during a steering transition is calculated. Here, the steering shift means that the steering operation state shifts from the cutting state to the switching state. When it is continuously determined that the cutting state is described above, the steering shift is determined when the switching state is determined. Then, the absolute value of the steering angle Sa at the time of steering transition is calculated as the steering angle Sam corresponding to the steering transition. Further, the actual turning state amount Jra when the steering is shifted is calculated as the turning state amount Jrm corresponding to the steering shift. Since there is a time delay in the actual turning state amount with respect to the steering operation, the maximum value of the actual turning state amount Jra immediately after the steering shift is determined can be calculated as the turning state amount Jrm corresponding to the steering shift. Since the time delay can be predicted in advance, the actual turning state amount Jra after the elapse of the predetermined time t3 after the determination of the steering shift can be calculated as the turning state amount Jrm corresponding to the steering shift.

  Next, the start / end of preload control is determined based on determination steps F130, F135, and F140. In step F130, it is determined whether the preload control is currently being executed. If the preload control is not executed and a negative determination is made in step F130, the arithmetic processing proceeds to step F135. In step F135, it is determined whether a preload control start condition is satisfied. Preload control start conditions will be described later. In step F135, when the start determination of the preload control is affirmed, the calculation process proceeds to step F145, and the preload control is started. On the other hand, if the start of the preload control is denied in step F135, the preload control is not started.

  If the preload control is being executed and an affirmative determination is made in step F130, the arithmetic processing proceeds to step F140. In step F140, it is determined whether a preload control termination condition is satisfied. The preload control termination condition will be described later. In step F140, when the preload control end determination is affirmed, the preload control is ended. On the other hand, if the end of the preload control is denied in step F140, the calculation process proceeds to step F145, and the preload control is continued.

  The start determination calculation of preload control will be described with reference to FIG. The start determination of the preload control is performed for each wheel.

  In step F200, based on the vehicle speed Vx read in step F100, it is determined that the vehicle speed Vx is equal to or greater than a predetermined value V1. If the vehicle speed Vx is less than the predetermined value V1 and a negative determination is made in step F200, the start of the preload control is denied and execution is prohibited. When the vehicle is low, a sudden yawing behavior that requires a highly responsive braking fluid pressure does not occur. If the vehicle speed Vx is equal to or higher than the predetermined value V1 and an affirmative determination is made in step F200, the arithmetic processing proceeds to step F205.

  In step F205, it is determined that the driver is not performing a braking operation based on the braking operation amount Bs read in step F100. If the braking operation is being performed (the braking operation member BP is being operated) and a negative determination is made in step F205, the start of the preload control is denied and execution is prohibited. This is because the braking fluid pressure is already generated in the wheel cylinder WCzz during the braking operation, and the effect of the preload control is not expected. If no braking operation is performed by the driver and an affirmative determination is made in step F205, the calculation process proceeds to step F210.

  In step F210, it is determined that the determination target wheel is not the current vehicle stability control target wheel based on the control state of the vehicle stability control read in step F110. If it is the current vehicle stability control target wheel and a negative determination is made in step F210, the start of the preload control is denied and execution is prohibited. This is because the brake fluid pressure is already generated in the wheel cylinder WCzz on the current target wheel of the vehicle stability control, and the effect of the preload control is not expected. If an affirmative determination is made in step F210 instead of the current vehicle stability control wheel, the calculation process proceeds to step F215.

  In step F215, based on the turning direction identified in step F112, it is determined whether the wheel (determination target wheel) on which the preload control is to be started is the turning outer front wheel. If the wheel for which preload control is to be started is not a turning outer front wheel and a negative determination is made in step F215, the start of preload control is denied for that wheel and execution is prohibited. A sudden yawing behavior that requires a highly responsive braking fluid pressure occurs during oversteering. To suppress this oversteering, it is effective to apply braking fluid pressure to the front wheels outside the turn. If the target wheel for the start determination of the preload control is the turning outer front wheel, and an affirmative determination is made in step F215, the arithmetic processing proceeds to step F220. Steps F210 and F215 correspond to the preload target wheel calculation block B153 in FIG.

  In step F220, based on the steering angular velocity dSak at the time of turning steering calculated in step F115, it is determined that the turning steering angular velocity dSak is equal to or greater than a predetermined value Tk1. If the turning steering angular velocity dSak is less than the predetermined value Tk1 and a negative determination is made in step F220, the start of the preload control is denied and execution is prohibited. When the steering angular velocity dSak at the time of turning steering is small, a temporal phase difference between the front wheel lateral force and the rear wheel lateral force is difficult to occur, so that a rapid yawing behavior that requires a highly responsive braking fluid pressure does not occur. . If the steering angular velocity dSak during the turning steering is equal to or greater than the predetermined value Tk1 and an affirmative determination is made in step F220, the calculation process proceeds to step F225.

  In step F225, based on the steering angular velocity dSam at the time of reverse steering calculated in step F120, it is determined that the reverse steering angular velocity dSam is equal to or greater than a predetermined value Tm1. If the turning steering angular velocity dSam is less than the predetermined value Tm1 and a negative determination is made in step F225, the start of the preload control is denied and execution is prohibited. When the steering angular velocity dSam at the time of the turn-back steering is small, a temporal phase difference between the front wheel lateral force and the rear wheel lateral force is unlikely to occur, and thus a rapid yawing behavior that requires a highly responsive braking fluid pressure does not occur. . When the steering angular velocity dSam during the turn-back steering is equal to or greater than the predetermined value Tm1 and an affirmative determination is made in step F225, the calculation process proceeds to step F230.

  In step F230, it is determined that the turning state amount Jrm is equal to or greater than the predetermined value Tj1 based on the turning state amount Jrm corresponding to the steering shift calculated in step F125. If the turning state quantity Jrm is less than the predetermined value Tj1 and a negative determination is made in step F230, the start of the preload control is denied and execution is prohibited. When the turning state amount Jrm corresponding to the steering transition is small, the rear wheel lateral force does not reach the limit, and a rapid yawing behavior that requires a highly responsive braking fluid pressure does not occur. If the turning state amount Jrm corresponding to the steering shift is equal to or greater than the predetermined value Tj1, and an affirmative determination is made in step F230, the calculation process proceeds to step F235, and preload control is started.

  In the determination in step F230, the steering angle Sam corresponding to the steering shift calculated in step F125 can be used instead of the turning state amount Jrm corresponding to the steering shift. That is, in step F230, it is determined that the steering angle Sam corresponding to the steering shift calculated in step F125 is equal to or greater than the predetermined value Ts1. If the steering angle Sam is less than the predetermined value Ts1, and a negative determination is made in step F230, the start of the preload control is denied and execution is prohibited. When the steering angle Sam corresponding to the steering shift is small, the rear wheel lateral force does not reach the limit, and a rapid yawing behavior that requires a highly responsive braking fluid pressure does not occur. If the steering angle Sam corresponding to the steering transition is equal to or greater than the predetermined value Ts1 and an affirmative determination is made in step F230, the calculation process proceeds to step F235, and preload control is started.

  In step F230, a determination is made based on either the transition turning state amount Jrm or the transition steering angle Sam. When both of these two determination conditions are satisfied, the preload control is started. You can also Since the preload control is prohibited when either one of the determination condition of the turning state quantity Jrm at the time of transition and the determination condition of the steering angle Sam at the time of transition is denied, the reliability of the start determination is improved.

  In step F235, preload control is started. Details of the preload control will be described later. The determination blocks from Step F200 to Step F230 do not have to include all of them, and any one or more of them can be omitted.

  The preload control end determination calculation will be described with reference to FIG. The end determination of the preload control is performed for each wheel.

  In step F300, the time during which the preload control is continued (continuation time Typ) is counted and calculated. In step F305, based on the control state of the vehicle stability control read in step F110, the time during which the vehicle stability control is continued (continuation time Tes) is counted and calculated.

  In step F310, based on the vehicle speed Vx read in step F100, it is determined that the vehicle speed Vx is equal to or less than a predetermined value V2 (<predetermined value V1). If the vehicle speed Vx is equal to or less than the predetermined value V2 and an affirmative determination is made in step F310, the calculation process proceeds to step F335, the preload control is terminated, and the brake fluid pressure by the preload control is set to “0”. When the speed of the vehicle becomes low, a rapid yawing behavior that requires a highly responsive braking fluid pressure does not occur, and the need for preload control is eliminated. On the other hand, when the vehicle speed Vx is greater than the predetermined value V2 and a negative determination is made in step F310, the calculation process proceeds to step F315 and the preload control is continued.

  In step F315, based on the braking operation amount Bs read in step F100, it is determined that the driver has started the braking operation after starting the preload control. When the braking operation by the driver is started and an affirmative determination is made in step F315, the calculation process proceeds to step F335, the preload control is terminated, and the brake fluid pressure by the preload control is set to “0”. This is because when the brake fluid pressure is generated in the wheel cylinder WCzz, the need for preload control is eliminated. On the other hand, if no braking operation is performed by the driver and a negative determination is made in step F315, the calculation process proceeds to step F320, and the preload control is continued.

  In step F320, based on the steering angle Sa read in step F105 and the actual turning state amount Jra, the turning direction corresponding to the steering angle Sa matches the turning direction corresponding to the actual turning state amount Jra. Is determined. If both turning directions coincide and an affirmative determination is made in step F320, the calculation process proceeds to step F335, the preload control is terminated, and the brake fluid pressure by the preload control is set to “0”. The coincidence of the above two turning directions means the convergence of the oversteer state, so that the preload control is not necessary. On the other hand, if the above two turning directions are different and a negative determination is made in step F320, the calculation process proceeds to step F325, and the preload control is continued.

  In step F325, based on the preload control duration Typ calculated in step F300, it is determined that the preload control duration Typ is equal to or longer than the predetermined time Typ1. If the preload control continuation time Typ is equal to or longer than the predetermined time Ty1 and an affirmative determination is made in step F325, the calculation process proceeds to step F335, the preload control is terminated, and the braking hydraulic pressure by the preload control is set to “0”. . Since the vehicle stability control is not started after a lapse of a predetermined time since the sudden turn-back steering is performed, the need for the preload control is eliminated. On the other hand, if the preload control continuation time Typ is less than the predetermined time Ty1 and a negative determination is made in step F325, the calculation process proceeds to step F330, and the preload control is continued.

  In step F330, based on the vehicle stability control duration Tes calculated in step F305, it is determined that the vehicle stability control duration Tes is equal to or longer than the predetermined time Te1. If the vehicle stability control continuation time Tes is equal to or longer than the predetermined time Te1 and an affirmative determination is made in step F330, the calculation process proceeds to step F335, the preload control is terminated, and the brake fluid pressure by the preload control is set to “0”. Is done. When the vehicle stability control is started and a predetermined time elapses, the brake fluid pressure is already generated in the wheel cylinder WCzz, so that the preload control is not necessary. On the other hand, if the vehicle stability control continuation time Tes is less than the predetermined time Te1, and a negative determination is made in step F330, the preload control is continued.

  The determination blocks from Step F310 to Step F330 do not have to include all of them, and any one or more of them can be omitted.

  The preload control calculation block B150 in FIG. 3 will be described with reference to FIG. In particular, the target control amount (target preload amount) of the preload control calculated in the preload amount calculation block B152 will be described. The brake hydraulic pressure of the wheel cylinder WCzz necessary for the preload control is calculated as the target preload (target preload amount) Ppt. The target preload Ppt is calculated for each wheel.

  In the target preload amount calculation block B200, a target preload Ppt (target preload amount) for preload control is calculated based on the switching steering angular velocity dSam calculated in step F120. The target preload Ppt is calculated as “0” in the range where the turning steering angular velocity dSam is “0” or more and less than the predetermined value Tm1 (corresponding to the predetermined value Tm1 in Step F225). In a range where the turning steering angular velocity dSam is equal to or greater than the predetermined value Tm1, the target preload Ppt is calculated as a characteristic (characteristic Chp1) that increases from “0” as the turning steering angular velocity dSam increases.

  Further, the target preload Ppt is calculated as “0” when the turning steering angular velocity dSam is “0” or more and less than the predetermined value Tm1, and the target preload Ppt is a predetermined value when the turning steering angular velocity dSam is equal to or more than the predetermined value Tm1. It can be calculated as a characteristic (characteristic Chp2) that becomes Pp1. In this case, instead of the input of the turning-back steering angular velocity dSam, a signal (control flag) indicating that the determination condition of Step F225 is satisfied (positive determination) can be input to the calculation block B200.

  The target preload Ppt calculated in the calculation block B200 can be adjusted based on the turning steering angular velocity dSak. Based on the cutting steering angular velocity dSak calculated in step F115, the adjustment coefficient Ksk is calculated in the adjustment calculation block B210 based on the cutting steering angular velocity. In the range where the turning steering angular velocity dSak is “0” or more and less than the predetermined value Tk1 (corresponding to the predetermined value Tk1 in Step F220), the coefficient Ksk is calculated as “0”. In the range where the turning steering angular velocity dSak is equal to or greater than the predetermined value Tk1, the coefficient Ksk is calculated as a characteristic (characteristic Kch1) that increases from “1” as the turning steering angular velocity dSak increases.

  The coefficient Ksk is calculated to be “0” when the cutting steering angular velocity dSak is “0” or more and less than the predetermined value Tk1, and when the cutting steering angular velocity dSak is the predetermined value Tk1 or more, the coefficient Ksk is the predetermined value Kk1 ( It can be calculated as a characteristic (characteristic Kch2) having a value greater than “1”. In this case, instead of the input of the turning steering angular velocity dSak, a signal (control flag) indicating that the determination condition in Step F220 is satisfied (positive determination) can be input to the calculation block B210.

  The multiplication means B240 multiplies the target preload Ppt output from the calculation block B200 by the coefficient Ksk output from the calculation block B210, thereby adjusting the target preload Ppt based on the turning steering angular velocity dSak. The target preload Ppt calculated based on the turning-back steering angular velocity dSam is adjusted based on the magnitude of the turning steering angular velocity dSak by the calculation block B210 and the multiplication unit B240. That is, the target preload Ppt is increased and adjusted in accordance with the increase of the turning steering angular velocity dSak.

  The target preload Ppt calculated in the calculation block B200 can be adjusted based on the turning state amount Jrm at the time of transition (or the steering angle Sam at the time of transition). Based on the transition turning state quantity Jrm (or transition steering angle Sam) calculated in step F125, the adjustment coefficient Ksm is calculated in the calculation block B220. Transition turning state quantity Jrm (or transition steering angle Sam) is “0” or more, and predetermined value Tj1 (corresponding to predetermined value Tj1 in step F230) (or predetermined value Ts1 (corresponding to predetermined value Ts1 in step F230)) ), The coefficient Ksm is calculated as “0”. When the transition turning state amount Jrm (or the transition steering angle Sam) is equal to or greater than the predetermined value Tj1 (or the predetermined value Ts1), the transition turning state amount Jrm (or the transition steering angle Sam) increases. The coefficient Ksm is calculated as a characteristic (characteristic Mch1) that increases from “1”.

  Further, in the range where the turning state quantity Jrm at transition (or the steering angle Sam at transition) is “0” or more and less than the predetermined value Tj1 (or the predetermined value Ts1), the coefficient Ksm is calculated to be “0”. A characteristic (characteristic Mch2) in which the coefficient Ksm becomes a predetermined value Km1 (a value larger than “1”) in a range where the turning state amount Jrm (or the transition steering angle Sam) is equal to or larger than the predetermined value Tj1 (or the predetermined value Ts1). Can be computed as In this case, a signal (control flag) indicating that the determination condition in step F230 is satisfied (positive determination) is sent to the calculation block B220 in place of the input of the turning turning state amount Jrm (or the shifting steering angle Sam). Can be entered.

  The predetermined value Tj1 (or the predetermined value Ts1) can be adjusted based on the road surface friction coefficient μmax acquired by the road surface friction coefficient acquisition unit B230. The road surface friction coefficient μmax is obtained by a known method. When the road surface friction coefficient μmax is small, the predetermined value Tj1 (or predetermined value Ts1) is adjusted to a smaller predetermined value Tj3 (<predetermined value Tj1) (or predetermined value Ts3 (<predetermined value Ts1)). At this time, the characteristic Mch1 is changed to the characteristic Mch3, and in the range where the transitional turning state amount Jrm (or the transitional steering angle Sam) is “0” or more and less than the predetermined value Tj3 (or the predetermined value Ts3), The coefficient Ksm is calculated as “0”, and when the transition turning state amount Jrm (or the transition steering angle Sam) is equal to or larger than the predetermined value Tj3 (or the predetermined value Ts3), the transition turning state amount Jrm (or The coefficient Ksm can be calculated to increase from “1” as the transition steering angle Sam) increases. Further, the characteristic Mch2 is changed to the characteristic Mch4, and in the range where the turning state amount Jrm (or the steering angle Sam at the time of transition) is “0” or more and less than the predetermined value Tj3 (or the predetermined value Ts3), the coefficient Ksm is calculated as “0”, and the coefficient Ksm is a predetermined value Km1 (“1”) in a range where the turning state amount Jrm (or the steering angle Sam at the time of transition) is equal to or larger than the predetermined value Tj3 (or the predetermined value Ts3). It can be calculated as a characteristic having a larger value. By considering the road surface friction coefficient μmax, the degree of vehicle behavior reaching the turning limit in the first steering can be evaluated, and a sudden yawing behavior in the second steering can be predicted.

  The multiplication means B240 multiplies the target preload Ppt output from the calculation block B200 by the coefficient Ksm output from the calculation block B220, so that the target preload Ppt is converted into the turning state amount Jrm during transition (or the steering angle during transition). (Sam). The target preload Ppt calculated based on the turning-back steering angular velocity dSam is adjusted by the calculation block B220 and the multiplication unit B240 based on the magnitude of the turning state variable Jrm (or the shifting steering angle Sam). . In other words, the target preload Ppt is increased and adjusted in accordance with the increase in the transition turning state amount Jrm (or the transition steering angle Sam). Note that at least one of the operation blocks B210 and B220 may be omitted.

  Although the calculation of the target preload (hydraulic pressure value) Ppt of the preload control has been described with reference to FIG. 7, the case of calculating the target preload fluid amount Vft instead of the target preload Ppt will be described with reference to FIG. Since the preload can be applied if the brake fluid is moved to the wheel cylinder WCzz, the amount of brake fluid to be moved to the wheel cylinder WCzz necessary for the preload control is calculated as the target preload fluid amount Vft. The target preload fluid amount (target preload amount) Vft is calculated for each wheel.

  When a brake fluid amount (brake fluid volume) is supplied to the wheel cylinder WCzz, first, the pad gap is reduced, and when the brake pad contacts the brake rotor, a brake fluid pressure is generated. When a slight amount of brake fluid is supplied to the wheel cylinder WCzz, no brake fluid pressure is generated due to the pad gap or the like. However, even in such a state, the response of the brake fluid pressure is improved by closing the pad gap. Based on the specifications of the brake means such as the wheel cylinder WCzz, the relationship between the brake fluid amount and the brake fluid pressure can be obtained in advance. In the relationship between the brake fluid amount and the brake fluid pressure, a brake fluid amount Vfx (a predetermined value determined in advance by the brake specifications) when the brake fluid pressure rises from “0” is obtained, and the target preload fluid amount is determined accordingly. The characteristic for calculating Vft can be determined. When the brake fluid amount (brake fluid amount) by the preload control is less than the predetermined value Vfx, no brake fluid pressure is generated, and when the brake fluid amount exceeds the predetermined value Vfx, the brake fluid pressure is generated.

  In the target preload amount pressure calculation block B205, a target preload fluid amount Vft (target preload amount) for preload control is calculated based on the turning-back steering angular velocity dSam. In the range where the turning steering angular velocity dSam is “0” or more and less than the predetermined value Tm1 (corresponding to the predetermined value Tm1 in Step F225), the target preload fluid amount Vft is calculated as “0”. In the range where the turning steering angular velocity dSam is equal to or greater than the predetermined value Tm1, it is calculated as a characteristic (characteristic Vch1) in which the target preload fluid amount Vft increases as the turning steering angular velocity dSam increases. With the preload control, a brake fluid pressure corresponding to the target preload fluid amount Vft is generated in the wheel cylinder WCzz.

  As indicated by the characteristic Vch2, in a range where the turning steering angular velocity dSam is “0” or more and less than the predetermined value Tm1, the target preload fluid amount Vft is calculated as “0”, and the turning steering angular velocity dSam is a range where the turning value is greater than or equal to the predetermined value Tm1. Then, the target preload fluid amount Vft is calculated as a predetermined value Vf2 (a value smaller than the predetermined value Vfx). With this characteristic Vch2, no braking hydraulic pressure is generated even when the preload control is executed. However, since the pad gap is reduced, the response of the brake fluid pressure can be improved. In this case, instead of the input of the turning-back steering angular velocity dSam, a signal (control flag) indicating that the determination condition in Step F225 is satisfied (positive determination) can be input to the calculation block B205.

  As indicated by the characteristic Vch3, in the range where the turning steering angular velocity dSam is “0” or more and less than the predetermined value Tm1, the target preload fluid amount Vft is calculated as “0”, and the turning steering angular velocity dSam is a range where the turning value is equal to or more than the predetermined value Tm1. Then, the target preload fluid amount Vft is calculated as a predetermined value Vf3 (a value larger than the predetermined value Vfx). In this characteristic Vch3, the pad gap is eliminated by the preload control, and the brake fluid pressure corresponding to the target preload fluid amount Vft is generated in the wheel cylinder WCzz. In this case, instead of the input of the turning-back steering angular velocity dSam, a signal (control flag) indicating that the determination condition in Step F225 is satisfied (positive determination) can be input to the calculation block B205.

  As indicated by the characteristic Vch4, when the turning steering angular velocity dSam is equal to or greater than “0” and less than the predetermined value Tm1, the target preload fluid amount Vft is calculated as “0”, and the switching steering angular velocity dSam is equal to or greater than the predetermined value Tm1. In a range less than the value Tm3, the target preload fluid amount Vft is calculated as a predetermined value Vf2 (a value smaller than the predetermined value Vfx). In the range where the turning steering angular velocity dSam is equal to or greater than the predetermined value Tm3, the target preload fluid amount Vft is calculated as the predetermined value Vf3 (a value larger than the predetermined value Vfx). In this characteristic Vch4, no braking hydraulic pressure is generated even if the preload control is executed in the range where the turning steering angular velocity dSam is not less than the predetermined value Tm1 and less than the predetermined value Tm3. However, since the pad gap is reduced, the response of the brake fluid pressure is improved. Further, in the range where the turning steering angular velocity dSam is equal to or greater than the predetermined value Tm3, the pad gap is eliminated by the preload control, and the brake fluid pressure corresponding to the target preload fluid amount Vft is generated in the wheel cylinder WCzz.

  Similar to FIG. 7, the target preload fluid amount Vft can be adjusted based on B210, B220, B230, and B240. Since these calculation methods are the same, the description thereof is omitted.

  The multiplication means B240 multiplies the target preload fluid amount Vft output from the calculation block B205 by the coefficient Ksk output from the calculation block B210, so that the target preload fluid amount Vft is adjusted based on the turning steering angular velocity dSak. The The target preload fluid amount Vft calculated based on the turning steering angular velocity dSam is adjusted based on the magnitude of the turning steering angular velocity dSak by the calculation block B210 and the multiplying means B240. That is, the target preload fluid amount Vft is increased and adjusted as the turning steering angular velocity dSak increases.

  The multiplication means B240 multiplies the target preload fluid amount Vft output from the calculation block B205 by the coefficient Ksm output from the calculation block B220, so that the target preload fluid amount Vft is changed to the turning state amount Jrm during transition (or Adjustment is made based on the steering angle (Sam) at the time of transition. The target preload fluid amount Vft calculated based on the turning-back steering angular velocity dSam by the calculation block B220 and the multiplication unit B240 is adjusted based on the magnitude of the transition state Jrm (or the transition steering angle Sam). Is done. That is, the target preload fluid amount Vft is increased and adjusted in accordance with the increase in the transition turning state amount Jrm (or the transition steering angle Sam). Note that at least one of the operation blocks B210 and B220 may be omitted.

  The operation and effect of the preload control will be described with reference to FIG.

  As shown by the characteristic Chb, in the first steering, when the turning steering is performed from the origin 0 to the point b1, and then the turning steering is performed from the point b1 to the point b2, the magnitude (absolute value) of the steering angular velocity dSam at the turning steering. ) Is equal to or greater than the predetermined value Tm1, execution of preload control is started for the second steering. At this time, the preload control start condition can be that the magnitude (absolute value) of the steering angular velocity dSa in the cut state in the first steering is equal to or greater than the predetermined value Tk1. Further, the preload control start condition can be that the magnitude (absolute value) of the steering angle Sam at the time of transition from the turning state to the turning-back state in the first steering is equal to or greater than the predetermined value Ts1. Also, the magnitude (absolute value) of the actual turning state amount Jrm corresponding to the transition from the turning state to the turning back state in the first steering (the actual turning state amount at the point e1 at the time of steering transition, the actual turning state amount after the steering transition) The maximum value (actual turning state quantity at point e2) and the magnitude of any of the actual turning state quantities at point e3 after elapse of a predetermined time t3 from the time of steering shift are equal to or greater than a predetermined value Tj1. Can be used as a precondition for starting preload control. Prediction control is performed by predicting the abrupt yawing behavior by evaluating the steering state of the first steering according to the magnitude of the infeed steering angular velocity, the steering angle at the time of steering transition, or the actual amount of turning state. Can be executed appropriately.

  The preload control is performed on a wheel to which no brake fluid pressure is applied by vehicle stability control (oversteer suppression control). Further, the turning direction of the vehicle is identified based on the steering angle, outside in the turning direction (the turning direction of the first steering) opposite to the turning direction when the steering angle decreases (the turning direction of the second steering), and A preload can be applied to the braking means for the front wheels. The preload control is performed on the turning outer front wheel. In FIG. 9, the preload is applied to the left front wheel, which is the front outer wheel in the second steering (right turn). Compared to the case where the preload control is not performed, the response of the brake fluid pressure is improved.

  In FIG. 9, the brake fluid pressure control by the vehicle stability control (oversteer suppression control) is executed in the first steering, but the oversteer state is not so large that the oversteer suppression control is started in the first steering. However, a sudden yawing behavior may occur in the second steering. Therefore, even if the oversteer state of the vehicle is not detected (identified), the preload control is started when the preload control start condition is satisfied.

  When the preload control is started and then the vehicle stability control (oversteer suppression control) is executed, the brake fluid pressure is generated in the brake means. At this time, the need for preload control is eliminated. Therefore, the continuation time Tes from the start of the vehicle stability control is counted, and when the continuation time Tes exceeds the predetermined time Te1, the preload control is terminated and the applied preload is set to “0”. Further, when the vehicle stability control end information is acquired and the vehicle stability control ends, the preload control can be ended and the preload can be set to “0”.

  Further, even when the preload control is executed, the vehicle stability control (oversteer suppression control) may not be executed. Therefore, the continuation time Typ from when the preload control is started is counted, and when the continuation time Typ exceeds the predetermined time Ty1, the preload control can be terminated and the preload can be set to “0”.

  As shown by the characteristic Chc, when the turning steering angular velocity (steering angular velocity from the origin 0 to the point c1) of the first steering is less than the predetermined value Tk1, since the rapid yawing behavior does not occur, the preload control is prohibited. The Further, as indicated by the characteristic Chd, the magnitude (absolute value) of the steering angle Sam at the time of transition from the turning state of the first steering to the turning-back state (the steering angle Sa2 at the point d1), a predetermined value Ts1 (threshold value). If it is less than this, pre-load control is prohibited because a rapid yawing behavior does not occur. Also, the magnitude (absolute value) of the actual turning state amount Jrm corresponding to the transition from the turning state of the first steering to the turning back state (the absolute value of the actual turning state amount at the time of steering transition, the maximum value of the actual turning state amount immediately after the steering transition) If the magnitude of any of the actual turning state values after a predetermined time has elapsed from the time of steering shift is less than the predetermined value Tj1 (threshold), rapid yawing behavior does not occur. Preload control is prohibited.

(Second Embodiment)
Next, a vehicle motion control device according to a second embodiment of the present invention will be described using the functional block diagram of FIG. In the second embodiment, in addition to the preload control in the first embodiment, the start threshold value of the vehicle stability control (oversteer suppression control) is adjusted based on the steering operation state of the driver. This is different from the first embodiment. Arithmetic processes with the same symbols as those in the first embodiment are the same as those in the first embodiment, and thus description thereof is omitted. Only the differences will be described below.

  In the functional block diagram of FIG. 10, a threshold adjustment computation block B180 is added to the functional block diagram of FIG. 3, and the computation block B120 is replaced with a computation block B125.

  In the calculation block B180, a start threshold Th (simply referred to as a threshold) for starting vehicle stability control (oversteer suppression control) is calculated. The calculation block B180 includes a start / end calculation block B181 for determining start / end of threshold adjustment, an adjustment threshold determination calculation block B182 for calculating the adjusted threshold, and threshold adjustment. It is comprised by adjustment object wheel calculation block B183 which determines the object wheel to perform.

  The vehicle stability control calculation block B125 calculates a target braking hydraulic pressure Pot (or target slip Spt) that is a target braking amount for performing vehicle stability control that suppresses oversteer based on a threshold value Th or the like. In the calculation characteristic (calculation map) for calculating the target braking amounts Pot and Spt, the initial characteristic is set as a characteristic represented by the characteristic Pch1. In a range where the oversteer state quantity Jos (or the actual turning state quantity Jra) is less than the predetermined value Tho, the target braking amounts Pot and Spt are calculated to be “0”, and the oversteer state quantity Jos (or the actual turning state quantity Jra) is calculated. In a range equal to or greater than the predetermined value Tho, the target braking amounts Pot and Spt are calculated as characteristics that increase from “0” as the oversteer state amount Jos (or the actual turning state amount Jra) increases.

  When the threshold value adjustment is executed, the vehicle stability control start threshold value is changed from the predetermined value Tho (initial value) to the adjustment threshold value Th (a value smaller than the predetermined value Tho). The characteristic for calculating the target braking amounts Pot and Spt is adjusted from the characteristic Pch1 to the characteristic Pch2. Vehicle stability control is started earlier by adjusting the threshold. By combining the preload control and the threshold adjustment that accelerates the start of the vehicle stability control, it is possible to more effectively cope with a sudden yawing behavior (excessive oversteer state).

  FIG. 11 is a control flowchart for the threshold value adjustment calculation of the calculation block B180, and corresponds to the control flow chart of the preload control in FIG. The threshold adjustment of FIG. 11 is explained by replacing “F” and “preload control” of the arithmetic processing block in FIG. 4 and the description thereof with “G” and “threshold adjustment”, respectively. can do.

  FIG. 12 is a control flow diagram for the threshold adjustment start determination calculation, and corresponds to the control flow diagram of the preload control start determination calculation of FIG. The symbols “F”, “V1”, “Tk1”, “Tm1”, “Tj1”, “Ts1”, and “preload control” of the arithmetic processing block in FIG. By replacing “V3”, “Tk2”, “Tm2”, “Tj2”, “Ts2”, and “threshold adjustment”, the threshold adjustment start determination calculation of FIG. 12 can be described.

  FIG. 13 is a control flow diagram of the threshold adjustment end determination calculation. The threshold adjustment end determination is performed for each wheel.

  In step G400, the time during which the threshold adjustment is continued (duration Tcs) is counted and calculated.

  In step G410, based on the calculated threshold adjustment duration Tcs, it is determined that duration Tcs is equal to or greater than predetermined time Tc2. If the duration time Tcs is equal to or longer than the predetermined time Tc2 and an affirmative determination is made in step G410, the arithmetic process proceeds to step G430, the threshold value adjustment is terminated, and the threshold value is returned to Tho (initial value). Since the vehicle stability control is not started after a predetermined time has elapsed since the sudden turn-back steering is performed, it is not necessary to adjust the threshold value. On the other hand, if the duration Tcs is less than the predetermined time Tc2 and a negative determination is made in step G410, the calculation process proceeds to step G420, and the threshold adjustment is continued.

  In step G420, it is determined whether the vehicle stability control has been completed based on the control state of the vehicle stability control read in step G110. If the vehicle stability control has been completed and an affirmative determination is made in step G420, the calculation process proceeds to step G430, the threshold value adjustment is terminated, and the threshold value is returned to Tho (initial value). When the vehicle stability control is finished, it is not necessary to adjust the threshold value. On the other hand, if the vehicle stability control is not finished and a negative determination is made in step G420, the threshold adjustment is continued. At least one of steps G410 and G420 can be omitted.

  The threshold adjustment calculation block B180 in FIG. 10 will be described with reference to FIG. In particular, an adjustment value for threshold adjustment (also referred to as adjustment threshold Th) calculated in the adjustment threshold determination calculation block B182 will be described. The adjustment threshold value Th is calculated for each wheel.

  Based on the turning steering angular velocity dSam calculated in step G120, an adjustment threshold value Th for adjusting the vehicle stability control start threshold value is calculated in the adjustment threshold value calculation block B300. In the range where the turning steering angular velocity dSam is “0” or more and less than the predetermined value Tm2 (corresponding to the predetermined value Tm2 in Step G225), the adjustment threshold value Th is calculated as an initial value Tho (predetermined value). In the range where the turning steering angular velocity dSam is equal to or greater than the predetermined value Tm2, the adjustment threshold value Th is calculated as a characteristic (characteristic Tch1) that decreases from the predetermined value Tho as the switching steering angular velocity dSam increases.

  Further, in the range where the turning steering angular velocity dSam is “0” or more and less than the predetermined value Tm2, the adjustment threshold Th is calculated as an initial value Tho (predetermined value), and in the range where the turning steering angular velocity dSam is the predetermined value Tm2 or more. The adjustment threshold value Th can be calculated as a characteristic (characteristic Tch2) having a predetermined value Thn (a value smaller than the initial value Tho). In this case, instead of the input of the turning steering angular velocity dSam, a signal (control flag) indicating that the determination condition in step G225 is satisfied (positive determination) can be input to the calculation block B300.

  The adjustment threshold value Th calculated in the calculation block B300 can be adjusted based on the turning steering angular velocity dSak. Based on the cutting steering angular velocity dSak calculated in step G115, the adjustment coefficient Ktk is calculated in the adjustment calculating block B310 based on the cutting steering angular velocity. In the range where the turning steering angular velocity dSak is “0” or more and less than the predetermined value Tk2 (corresponding to the predetermined value Tk2 in Step G220), the coefficient Ktk is calculated as “1”. In the range where the turning steering angular velocity dSak is equal to or greater than the predetermined value Tk2, the coefficient Ktk is calculated as a characteristic (characteristic Chk1) that decreases from “1” as the turning steering angular velocity dSak increases.

  Further, the coefficient Ktk is calculated as “1” in the range where the turning steering angular velocity dSak is equal to or greater than “0” and less than the predetermined value Tk2, and in the range where the cutting steering angular velocity dSak is equal to or greater than the predetermined value Tk2, the coefficient Ktk is the predetermined value Kk2 ( It can be calculated as a characteristic (characteristic Chk2) having a value smaller than “1”. In this case, instead of the input of the turning steering angular velocity dSak, a signal (control flag) indicating that the determination condition of Step G220 is satisfied (positive determination) can be input to the calculation block B310.

  The multiplication means B340 multiplies the adjustment threshold value Th output from the calculation block B300 by the coefficient Ktk output from the calculation block B310, so that the adjustment threshold value Th is adjusted based on the turning steering angular velocity dSak. The The adjustment threshold Th calculated based on the turning-back steering angular velocity dSam is adjusted based on the magnitude of the turning steering angular velocity dSak by the calculation block B310 and the multiplying unit B340. That is, as the turning steering angular velocity dSak increases, the adjustment threshold value Th is decreased and adjusted, and the vehicle stability control can be activated early.

  The adjustment threshold value Th calculated in the calculation block B300 can be adjusted based on the turning state quantity Jrm during transition (or the steering angle Sam during transition). Based on the transition-time turning state quantity Jrm (or transition-time steering angle Sam) calculated in step G125, the adjustment coefficient Ktm is calculated in the calculation block B320. Transition turning state quantity Jrm (or transition steering angle Sam) is “0” or more, and predetermined value Tj2 (corresponding to predetermined value Tj2 in step G230) (or predetermined value Ts2 (corresponding to predetermined value Ts2 in step G230)) ), The coefficient Ktm is calculated as “1”. When the transition turning state amount Jrm (or transition steering angle Sam) is in the range of the predetermined value Tj2 (or predetermined value Ts2) or more, the transition turning state amount Jrm (or transition steering angle Sam) increases. The coefficient Ktm is calculated as a characteristic (characteristic Chm1) that decreases from “1”.

  Also, in the range where the turning state quantity Jrm at transition (or the steering angle Sam at transition) is “0” or more and less than the predetermined value Tj2 (or the predetermined value Ts2), the coefficient Ktm is calculated as “1”, and at the time of transition A characteristic (characteristic Chm2) in which the coefficient Ktm becomes a predetermined value Km2 (a value smaller than “1”) in a range where the turning state amount Jrm (or the transition steering angle Sam) is equal to or larger than the predetermined value Tj2 (or the predetermined value Ts2). Can be computed as In this case, a signal (control flag) indicating that the determination condition of step G230 is satisfied (affirmation determination) is input to the calculation block B320 instead of the input of the transition state amount Jrm at transition (or the steering angle Sam at transition). Can be entered.

  The predetermined value Tj2 (or the predetermined value Ts2) can be adjusted based on the road surface friction coefficient μmax acquired by the road surface friction coefficient acquisition unit B330. The road surface friction coefficient μmax is obtained by a known method. When the road surface friction coefficient μmax is small, the predetermined value Tj2 (or predetermined value Ts2) is adjusted to a smaller predetermined value Tj4 (<predetermined value Tj2) (or predetermined value Ts4 (<predetermined value Ts2)). At this time, the above-mentioned characteristic Chm1 is changed to the characteristic Chm3, and in the range where the transitional turning state amount Jrm (or the transitional steering angle Sam) is “0” or more and less than the predetermined value Tj4 (or the predetermined value Ts4), The coefficient Ktm is calculated as “1”, and when the transition turning state amount Jrm (or the transition steering angle Sam) is equal to or larger than the predetermined value Tj4 (or the predetermined value Ts4), the transition turning state amount Jrm (or The coefficient Ktm can be calculated to decrease from “1” as the transition steering angle Sam) increases.

  Further, the characteristic Chm2 is changed to Chm4, and the coefficient Ktm is set in a range where the turning state amount Jrm (or the steering angle Sam at the time of transition) is “0” or more and less than the predetermined value Tj4 (or the predetermined value Ts4). Is calculated as “1”, and the coefficient Ktm is greater than the predetermined value Km2 (from “1”) in the range where the turning state variable Jrm (or the steering angle Sam during the transition) is equal to or greater than the predetermined value Tj4 (or the predetermined value Ts4) (Small value) can be calculated. By considering the road surface friction coefficient μmax, the degree to which the vehicle behavior reaches the turning limit in the first steering is evaluated, the sudden yawing behavior in the second steering is predicted, and the vehicle stability control is started early. The start threshold is adjusted so that it is possible.

  The multiplication means B340 multiplies the adjustment threshold value Th output from the calculation block B300 by the adjustment coefficient Ktm output from the calculation block B320, so that the adjustment threshold value Th changes to the turning-time turning state quantity Jrm (or , The shift steering angle Sam). The adjustment threshold Th calculated based on the turning steering angular velocity dSam by the calculation block B320 and the multiplication unit B340 is adjusted based on the magnitude of the transition state Jrm (or the transition steering angle Sam). Is done. That is, the adjustment threshold value Th is decreased and adjusted in accordance with an increase in the transitional turning state amount Jrm (or the transitional steering angle Sam). Note that at least one of the operation blocks B310 and B320 may be omitted.

  The second embodiment has been described above.

  The determination of the turning state of the steering operation and the turning-back state in steps F115, F120, G115, and G120 can be performed based on the sign of the steering angle Sa and the sign of the steering angular velocity dSa. If the sign of the steering angle Sa and the sign of the steering angular speed dSa match, the turning steering state is determined. If the sign of the steering angle Sa and the sign of the steering angular speed dSa are different, the reverse steering state is determined. The For example, in a left turn, if the steering angle Sa is a positive sign (+) and the steering angular velocity dSa is a positive sign (+), the cutting state is determined. On the other hand, if the steering angle Sa is a positive sign (+) and the steering angular velocity dSa is a negative sign (−) in the left turn, the turning-back state is determined.

  The determination of the transition from the turning state of the steering operation to the turning-back state in steps F125 and G125 can be performed based on the sign of the steering angle Sa and the sign of the steering angular velocity dSa. When the sign of the steering angle Sa and the sign of the steering angular velocity dSa coincide with each other (cut-in steering state), the sign of the steering angle Sa and the sign of the steering angular velocity dSa become different (turn-back steering state). Next, the steering shift is determined.

  The preload control is performed for each wheel, but the preload control can be performed for all the wheels. Further, the preload control can be performed on the front two wheels regardless of the turning direction of the vehicle. Although the start threshold value adjustment of the vehicle stability control is performed for each wheel, the threshold value adjustment can be performed for all the wheels. Further, the threshold adjustment can be performed on the front two wheels regardless of the turning direction of the vehicle. When the execution of the vehicle stability control is finished, the start threshold value adjustment of the preload control and the vehicle stability control can be finished.

1 is a schematic configuration diagram of a vehicle equipped with a vehicle motion control device according to a first embodiment of the present invention. It is a figure showing the whole brake actuator composition. It is a functional block diagram at the time of vehicle stability control etc. being performed by the vehicle motion control apparatus shown in FIG. FIG. 4 is a control flowchart relating to the entire preload control calculation process shown in FIG. 3. It is a control flowchart regarding the start determination of preload control. It is a control flowchart regarding the end determination of preload control. It is a functional block diagram regarding the 1st determination method of the target preload amount in preload control. It is a functional block diagram regarding the 2nd determination method of the target preload amount in preload control. It is a figure for demonstrating the effect | action and effect of 1st Embodiment. It is a functional block diagram at the time of vehicle stability control etc. being performed by the vehicle motion control apparatus which concerns on 2nd Embodiment of this invention. FIG. 11 is a control flow diagram related to the entire processing in the threshold adjustment calculation of the vehicle stability control shown in FIG. 10. It is a control flowchart regarding the start determination of threshold value adjustment. It is a control flow figure regarding the end judgment of threshold adjustment. It is a functional block diagram regarding the determination method of the adjustment threshold value in threshold value adjustment. It is a figure for demonstrating steering operation which avoids an obstacle etc.

Explanation of symbols

BRK ... brake actuator, ECU ... electronic control unit, YR ... yaw rate sensor, GY ... lateral acceleration sensor, WSzz ... wheel speed sensor, SA ... steering wheel operation angle sensor, SB ... front wheel steering angle sensor, WCzz ... wheel cylinder for each wheel

Claims (13)

Braking means provided on the wheels of the vehicle;
An actual turning amount acquisition means for acquiring an actual turning state amount of the vehicle;
Stability control means for executing stability control for applying braking fluid pressure to the braking means when oversteer of the vehicle is identified based on the actual amount of turning state;
Steering angle acquisition means for acquiring a steering angle by a driver of the vehicle;
Steering angular velocity calculating means for calculating a steering angular velocity based on the steering angle;
Preload applying means for applying a preload to the braking means based on the magnitude of the steering angular velocity when the steering angle decreases;
A vehicle motion control apparatus comprising: The vehicle motion control device according to claim 1, wherein the preload applying unit applies the preload when the magnitude of the steering angular velocity is a predetermined value or more. 3. The vehicle motion control apparatus according to claim 1, wherein the preload applying unit applies the preload even when oversteer of the vehicle is not identified. The said preload provision means provides the said preload to the said brake means of the wheel to which the said brake hydraulic pressure is not given by the said stability control, The Claim 1 thru | or 3 characterized by the above-mentioned. Vehicle motion control device. A turning direction identifying means for identifying a turning direction of the vehicle based on the steering angle;
The preload applying means applies the preload to the braking means of a wheel located outside the turning direction opposite to the turning direction when the steering angle decreases and in front of the vehicle. The vehicle motion control apparatus according to any one of claims 1 to 4. A braking operation acquisition means for acquiring an operation of the braking member of the driver;
The preload applying means determines that the operation of the braking member is performed based on the acquisition result of the braking operation acquisition means, and prohibits the application of the preload when the determination is affirmative. The vehicle motion control apparatus according to any one of claims 1 to 5. The preload applying means prohibits the application of the preload when the magnitude of the steering angular velocity when the steering angle increases is less than a predetermined value. The vehicle motion control apparatus described in 1. The preload applying means prohibits application of the preload when the magnitude of the steering angle when the steering angle shifts from an increasing state to a decreasing state is less than a predetermined value. The vehicle motion control apparatus according to claim 7. The preload applying means prohibits the application of the preload when the actual turning state amount corresponding to the shift of the steering angle from the increasing state to the decreasing state is less than a predetermined value. The vehicle motion control apparatus according to any one of claims 1 to 8. 10. The preload applying unit according to claim 1, wherein the preload applying unit ends the application of the preload when a predetermined time has elapsed since the stability control unit started the stability control. A vehicle motion control apparatus according to one of the above. The vehicle according to any one of claims 1 to 10, wherein the preload applying means finishes applying the preload when the stability control means finishes the stability control. Motion control device. 12. The preload application unit according to claim 1, wherein the preload application unit ends the application of the preload when a predetermined time elapses after the application of the preload is started. Vehicle motion control device. The stability control means adjusts a threshold value for starting the stability control to a small value based on the magnitude of the steering angular velocity when the steering angle decreases. Item 13. The vehicle motion control device according to any one of Items 12 above.