JP2010064721A - 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 on vehicle stability control. <P>SOLUTION: In the vehicle motion control device for executing the vehicle stability control for suppressing the over-steering of the vehicle, the rapid yawing behavior of the vehicle is predicted based on a steering angle, and pre-load control for giving pre-load to the appropriate braking means of a 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 the pre-load determined based on the degree of over-steer 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.
On the other hand, if the preload control is started even when the vehicle stability control is not started, only the preload control may be performed even though the vehicle stability control is not started. In order to execute the preload control, it is necessary to drive the brake fluid pressure control device (brake actuator), but when this is driven, a slight noise is generated, which makes the driver feel uncomfortable. Therefore, it is necessary to perform preload control only when necessary.

  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. 6, the plus sign (+) is the left turn direction and the minus sign (−) is the right turn direction as the 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. 6 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 can predict the occurrence of a sudden yawing behavior based on a steering operation, and can improve the response of braking hydraulic pressure in vehicle stability control only when necessary. An object of the present invention is to provide a vehicle motion control device.

  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. An oversteer identifying means for identifying the degree of oversteer of the vehicle, a stability control means for executing a stability control for applying a braking fluid pressure to the braking means based on the identification result of the oversteer identifying means, and a driver of the vehicle Steering angle acquisition means for acquiring a steering angle, steering angular speed calculation means for calculating a steering angular speed based on the steering angle, the identification result, and the magnitude of the steering angular speed when the steering angle decreases And a preload applying means for applying a preload to the braking means.

  Since the vehicle stability control and the preload application are executed based on the identification result of the oversteer identification unit, the preload application can be started at an appropriate timing immediately before the vehicle stability control is started. Further, when the steering angle decreases, that is, based on the magnitude of the steering angular velocity when the turning-back steering is performed, the preload is applied. Therefore, it is possible to predict a yawing behavior (oversteer behavior) that occurs abruptly and to apply preload only when necessary.

  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. An abrupt yawing behavior occurs when fast turnback steering is performed, and an appropriate preload can be applied to this behavior.

  In the vehicle motion control apparatus according to the present invention, the preload applying means can set a threshold value for starting the application of the preload to be smaller than a threshold value for starting the stability control. The preload application can be started before the stability control means starts applying the brake fluid pressure.

  The vehicle motion control apparatus according to the present invention further includes a turning direction determining unit that determines a turning direction of the vehicle based on the steering angle, and the preload applying unit is a turning direction when the steering angle is decreased. 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. By applying preload to the braking means for the front outer wheel that is most effective for suppressing oversteer, the effect of applying preload can be improved.

  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. It is determined that the member is being operated, and when the determination is affirmative, the adjustment of the threshold value can be prohibited. When preload application is unnecessary, the adjustment is prohibited, and unnecessary preload application can be avoided.

  In the vehicle motion control apparatus according to the present invention, the preload applying means prohibits the adjustment of the threshold value when the magnitude of the steering angular velocity when the steering angle increases is less than a predetermined value. Can do. 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 angle is steered is moderately less than a predetermined value, preloading is prohibited, and unnecessary preloading is avoided. be able to.

  In the vehicle motion control apparatus according to the present invention, the preload applying means is configured such that when the steering angle shifts from the increasing state to the decreasing state, the threshold value is less than a predetermined value. Value adjustment 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 magnitude of the steering angle when the steering operation shifts from the cutting state to the turning-back state is as small as less than a predetermined value, preload application is prohibited, and unnecessary preload application 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 threshold adjustment 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 amount of the actual turning state corresponding to when the steering operation shifts from the turning state to the turning-back state is less than a predetermined value, preload application is prohibited, and unnecessary preload application can be avoided.

  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 elapses after the stability control means starts the stability control. Can be set to “0”. Further, in the vehicle motion control apparatus according to the present invention, the preload applying means ends applying the preload when the stability control means ends the stability control, and sets the preload to “0”. can do. Furthermore, in the vehicle motion control apparatus according to the present invention, the preload applying means ends the application of the preload when a predetermined time has elapsed since the start of applying the preload, and sets the preload to “0”. Can be. By considering various conditions, it is possible to appropriately end the preload application.

  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 what is attached | subjected with the same symbol is the same, the overlapping description is abbreviate | omitted.

  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 calculates a target preload amount (target preload Ppt or target fluid amount Vft necessary for preload) based on the oversteer state amount Jos or the like. Further, since the preload control is performed for each wheel, it is determined to which wheel the preload is applied. Details of the preload control calculation 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 driving means (for example, an electric motor for a hydraulic pump, a driving 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 will be described with reference to FIG. First, in the reference preload amount calculation block B200, as in the vehicle stability control calculation block B120, a preload control reference amount (also referred to as a reference preload amount) Pref based on the oversteer state amount Jos (or the actual turning state amount Jra). , Vref is calculated. Here, the reference amounts are a reference preload (pressure) Pref and a reference preload fluid amount (volume) Vref, which correspond to the target preload Ppt and the target preload fluid amount Vft, respectively. In the range where the oversteer state quantity Jos (or actual turning state quantity Jra) is not less than “0” and less than the predetermined value Thp, the reference preload amounts Pref and Vref are calculated as “0”, and the oversteer state quantity Jos (or actual turning) In the range where the state quantity Jra) is equal to or greater than the predetermined value Thp, it is calculated as a characteristic (characteristic Rch1) in which the reference preload amounts Pref and Vref increase from “0” as the oversteer state quantity Jos (or the actual turning state quantity Jra) increases. Is done. Further, in the range where the oversteer state quantity Jos (or the actual turning state quantity Jra) is not less than “0” and less than the predetermined value Thp, the reference preload amounts Pref and Vref are calculated as “0”, and the oversteer state quantity Jos (or In the range where the actual turning state amount Jra) is equal to or greater than the predetermined value Thp, the reference preload amounts Pref and Vref can be calculated as the predetermined value Ya1 (characteristic Rch2). Here, the predetermined value Thp (start threshold value for preload control) is set to a value smaller than the predetermined value Th0 (start threshold value for vehicle stability control). Thus, the preload control is reliably started before the vehicle stability control is started.

  In the steering state calculation block B210, the state of the steering operation is calculated based on the steering angle Sa and the steering angular velocity dSa.

  In the cutting steering angular velocity calculation block B211, the steering angular velocity (also referred to as 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 the return steering angular velocity calculation block B212, the steering angular velocity (also referred to as the return 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 the turning state amount or steering angle calculation block B213 corresponding to the steering transition, the turning state amount corresponding to the steering transition (also referred to as a turning state amount during transition) Jrm, or the steering angle during the steering transition (also referred to as the transition steering angle). ) Sam 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.

  In the adjustment calculation block B220 based on the cutting steering angular velocity, the adjustment coefficient Ksk is calculated based on the cutting steering angular velocity dSak. In the range where the turning steering angular velocity dSak is “0” or more and less than the predetermined value Tk1, 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 of “1” or more.

  In the adjustment calculation block B230 based on the return steering angular velocity, the adjustment coefficient Kam is calculated based on the return steering angular velocity dSam. In the range where the turning steering angular velocity dSam is not less than “0” and less than the predetermined value Tm1, the coefficient Kam is calculated as “0”. In the range where the turning steering angular velocity dSam is equal to or greater than the predetermined value Tm1, the coefficient Kam is calculated as a characteristic (characteristic Mch1) that increases from “1” as the turning steering angular velocity dSam increases. Further, when the turning steering angular velocity dSam is not less than “0” and less than the predetermined value Tm1, the coefficient Kam is calculated as “0”, and when the turning steering angular velocity dSam is not less than the predetermined value Tm1, the coefficient Kam is the predetermined value Ka1 ( It can be calculated as a characteristic (characteristic Mch2) having a value of “1” or more.

  In the adjustment calculation block B220 based on the state quantity at the time of steering transition, the adjustment coefficient Ksm is calculated based on the turning state quantity Jrm at the time of transition (or the steering angle at the time of transition Sam). The coefficient Ksm is calculated to be “0” in a range where the transitional turning state amount Jrm (or the transitional steering angle Sam) is “0” or more and less than the predetermined value Tj1 (or the predetermined value Ts1). 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 Ich1) increasing 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 Ich2) in which the coefficient Ksm becomes a predetermined value Km1 (a value equal to or 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

  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 B250. 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 Tj2 (<predetermined value Tj1) (or predetermined value Ts2 (<predetermined value Ts1)). At this time, the characteristic Ich1 is changed to the characteristic Ich3, 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 Tj2 (or the predetermined value Ts2), 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 Tj2 (or the predetermined value Ts2), 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 Ich2 is changed to the characteristic Ich4, 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 Tj2 (or the predetermined value Ts2), the coefficient Ksm is calculated as “0”, and the coefficient Ksm is a predetermined value Km1 (“1”) when the turning state quantity Jrm (or the steering angle Sam at the time of transition) is equal to or greater than the predetermined value Tj2 (or the predetermined value Ts2). It can be calculated as a characteristic having the above 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 reference preload amounts Pref and Vref are multiplied by adjustment coefficients Ksk, Kam and Ksm by the multiplication means B260 to determine target preload amounts Ppt (target preload) and Vft (target preload fluid amount). Depending on the adjustment factors Ksk, Kam, and Ksm, the magnitude of the turning steering angular velocity dSak, the magnitude of the turning steering angular velocity dSam, and the magnitude of the turning turning state amount Jrm (or the transition steering angle Sam) are considered. The

  In the calculation of the adjustment coefficient Ksk, the coefficient Ksk is calculated as “0” when the cutting steering angular velocity dSak is “0” or more and less than the predetermined value Tk1, and the coefficient Ksk is “0” when the cutting steering angular velocity dSak is equal to or more than the predetermined value Tk1. 1 "or more is calculated. Therefore, the predetermined value Tk1 is the threshold value for starting the preload control, and the preload control is prohibited when the turning steering angular velocity dSak is less than the predetermined value Tk1. Accordingly, in the preload control calculation, preload application is prohibited when the steering angular velocity when the steering angle Sa increases (when the steering is turned) is less than the predetermined value Tk1.

  In the calculation of the adjustment coefficient Kam, the coefficient Kam is calculated as “0” when the turning steering angular velocity dSam is “0” or more and less than the predetermined value Tm1, and when the turning steering angular velocity dSam is the predetermined value Tm1 or more, the coefficient Kam is “ 1 "or more is calculated. Therefore, the predetermined value Tm1 is the threshold value for starting the preload control, and the preload control is prohibited when the turning steering angular velocity dSam is less than the predetermined value Tm1. Therefore, in the preload control calculation, the preload is applied when the magnitude of the steering angular speed when the steering angle Sa decreases (during turn-back steering) is equal to or greater than the predetermined value Tm1.

  In the calculation of the adjustment coefficient Ksm, the coefficient Kam is calculated as “0” in the range where the transitional turning state quantity Jrm is “0” or more and less than the predetermined value Tj1 (Tj2), and the transitional turning state quantity Jrm is the predetermined value Tj1 ( In the range of Tj2) or more, the coefficient Kam is calculated to be “1” or more. Therefore, the predetermined value Tj1 (Tj2) is the start threshold value for the preload control, and the preload control is prohibited in the range where the turning state amount Jrm at the time of transition is less than the predetermined value Tj1 (Tj2). In the preload control calculation, preload application is prohibited 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 Tj1 (Tj2).

  In the calculation of the adjustment coefficient Ksm, the coefficient Kam is calculated as “0” in the range where the transitional steering angle Sam is equal to or greater than “0” and less than the predetermined value Ts1 (Ts2), and the transitional steering angle Sam is equal to the predetermined value Ts1 ( In the range of Ts2) or more, the coefficient Kam is calculated to be “1” or more. Therefore, the predetermined value Ts1 (Ts2) is the start threshold value for the preload control, and the preload control is prohibited when the transition steering angle Sam is less than the predetermined value Ts1 (Ts2). Therefore, in the preload control calculation, preload application is prohibited when the magnitude of the steering angle when the steering angle shifts from the increasing state to the decreasing state is less than the predetermined value Ts1 (Ts2).

  Either one of them or both of them can be used to adjust the target preload amounts Ppt and Vft (adjustment by the coefficient Ksm) based on the turning turning state amount Jrm and the turning steering angle Sam. .

  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 determined based on the steering angle, and it is outside the turning direction (the turning direction of the second steering) opposite to the turning direction (the turning direction of the first steering) when the steering angle decreases. In addition, a preload can be applied to the braking means for the front wheels. In other words, the preload control is performed on the turning outer front wheel in the turning direction of the second steering. In FIG. 5, preload is applied to the left front wheel that is the outer front wheel in the second steering (right turn). Preload control start threshold Thp is set to be smaller than vehicle stability control start threshold Tho, and therefore preload control is reliably started before vehicle stability control is started, and preload control is not performed. Compared to the above, the response of the brake fluid pressure is improved.

  In FIG. 5, 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, the vehicle stability control end information is acquired, and when 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 indicated by the characteristic Chc, when the magnitude of the turning steering angular velocity (steering angular velocity from the origin 0 to the point c1) of the first steering is less than a predetermined value Tk1, since a rapid yawing behavior does not occur, preload control is performed. Is forbidden. 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.

  The determination of the turning state and the turning-back state of the steering operation 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 can be made 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.

  Based on the braking operation amount Bs, the operating state of the braking member BP of the driver is acquired, and when the braking member is operated (determining that the braking member is being operated is performed, the determination is affirmed) In this case, since the braking fluid pressure has already been generated by the driver's braking operation, the application of the preload by the preload control is prohibited.

  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.

1 is a schematic configuration diagram of a vehicle equipped with a vehicle motion control device according to an embodiment of the present invention. It is a figure which shows the whole structure of a brake actuator. 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. It is a functional block diagram regarding the preload control calculation shown in FIG. It is a figure for demonstrating the effect | action and effect of embodiment. 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 (11)

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;
Oversteer identifying means for identifying the degree of oversteer of the vehicle based on the actual turning state quantity;
Stability control means for executing stability control for applying a brake fluid pressure to the braking means based on the identification result of the oversteer identifying means;
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 identification result and 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. The vehicle according to claim 1 or 2, wherein the preload applying means sets a threshold value for starting the application of the preload to be smaller than a threshold value for starting the stability control. Motion control device. A turning direction determining means for determining a turning direction of the vehicle based on the steering angle;
The preload applying means applies the preload to the braking means of the wheel located outside and in front of the vehicle in a turning direction opposite to the turning direction when the steering angle decreases. The vehicle motion control device according to any one of claims 1 to 3. 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 4. 6. The preload applying device according to claim 1, wherein 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 6. 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 7. 9. 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 stability control unit starts the stability control. A vehicle motion control apparatus according to one of the above. The vehicle according to any one of claims 1 to 9, wherein the preload applying means finishes applying the preload when the stability control means finishes the stability control. Motion control device. 11. 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.