JP2013028201A - Vehicle behavior controller - Google Patents

Abstract

A preliminary brake pressure is applied with good responsiveness.
When performing vehicle behavior stabilization control for stabilizing the behavior of a vehicle 10 by generating a braking control amount in at least one of the front and rear turning outer wheels W _FL , W _RL (W _FR , W _RR ), When the condition for generating the braking control amount in the front and rear turning outer wheels W _FL and W _RL (W _FR and W _RR ) is satisfied, the inside of the front and rear turning inner wheels W _FR and W _RR (W _FL and W _RL ) Apply preliminary brake pressure to at least one of The application of the preliminary brake pressure is executed when a steering operation opposite to the current turning operation of the vehicle 10 is detected during the execution of the vehicle behavior stabilization control.
[Selection] Figure 1

Description

  The present invention relates to a vehicle behavior control device that stabilizes the behavior of a vehicle when a steering wheel is steered alternately (left and right) with respect to a steering center.

  When the steering operation is performed and the vehicle moves to a turning operation, the suspension on the turning outer wheel side sinks and starts rolling. In general, when the turn-back steering is performed, the roll amount tends to be larger in the second and subsequent steering operations than in the first steering operation from the steering center. This is because, for example, when the second steering operation is performed by turning back steering, a force in the return direction (that is, the extension direction) is generated in the suspension sinking by the first steering operation, and the lateral acceleration is quickly reversed in the reverse direction. This is because the roll motion by the first steering operation is changed to the roll motion in the reverse direction at a stretch, and the roll moment is increased. At that time, the yaw motion is also reversed in response to the second steering operation, and a larger yaw moment is applied to the vehicle body than when the first steering operation is performed.

  Conventionally, when the yaw moment generated when such a second or subsequent steering operation is excessive, the yaw moment in the reverse direction is applied to the vehicle body to reduce the yaw moment, and the excessive roll amount There is known a vehicle behavior control device that keeps the behavior of a vehicle in a stable state while suppressing (roll moment). This vehicle behavior control device controls a brake actuator and generates a yaw moment in the opposite direction by a braking force applied to at least one of the turning outer wheels. At this time, the vehicle behavior control device applies a brake fluid pressure (hereinafter referred to as “reserve” in advance) to at least one of the front and rear wheels that are currently turning inner wheels that are newly turned outer wheels by the next reverse steering operation. "Brake pressure") is applied, and control is performed so that the braking force can be applied with good responsiveness when the wheel actually becomes a turning outer wheel and it is necessary to generate the braking force. The preliminary brake pressure is generated by controlling the brake actuator. Hereinafter, the control for applying the preliminary brake pressure is referred to as “preliminary brake pressure control”.

  For example, Patent Documents 1 and 2 below disclose a vehicle behavior control device of this type. The vehicle behavior control device of Patent Document 1 performs suppression control of oversteer by generating a braking force on at least one of the turning outer wheels. During this suppression control, a steering operation in the anti-turning direction is performed. If detected, a preliminary brake pressure is applied to at least one of the current turning inner wheels that will be the next turning outer wheel in accordance with the steering operation. Further, the vehicle behavior control device of Patent Document 2 performs vehicle horizontal plane behavior control by automatic braking of the behavior control wheel, and the next behavior control wheel according to the combination of the current behavior control wheel and the change tendency of the yaw rate deviation. Thus, only this wheel is set as a preload control target wheel for applying a preparatory brake pressure.

JP 2008-254724 A JP 11-227586 A

  Preliminary brake pressure control can also achieve a certain effect even by a method that is implemented in response to detection of actual vehicle behavior or driver turning-back steering. However, in situations such as when sudden turn-back steering is performed, there is a possibility that the output of the preliminary brake pressure control is not in time or insufficient, and a sufficient effect cannot be obtained.

  In addition, in the preliminary brake pressure control based on the detected actual vehicle behavior and the driver's turnback steering, it is possible to ensure the responsiveness by setting the threshold, but the actual vehicle behavior, etc. There is a risk of causing unnecessary operation due to erroneous determination.

  Accordingly, the present invention provides a vehicle behavior control device that can improve the disadvantages of the conventional example and can apply the preliminary brake pressure with high responsiveness even when quick preliminary brake pressure output such as sudden steering is required. That is the purpose.

  In order to achieve the above-described object, the present invention provides a vehicle behavior stabilization control that stabilizes the vehicle behavior by generating a braking control amount on at least one of the front and rear turning outer wheels. In the case where a condition to be generated in each turning outer wheel is satisfied, a preliminary brake pressure is applied to at least one of the front and rear turning inner wheels.

  Here, it is preferable that the application of the preliminary brake pressure is executed when a steering operation opposite to the current turning operation of the vehicle is detected during the execution of the vehicle behavior stabilization control.

  When the vehicle behavior stabilization control is oversteer suppression control, it is desirable to apply the preliminary brake pressure to the front turning inner wheel.

  Since the vehicle behavior control device according to the present invention performs preliminary brake pressure control before detecting the behavior of the vehicle accompanying the turnback steering, the preliminary brake pressure is applied before the turning direction of the vehicle body is reversed by the driver's turnback steering. Can be kept. Therefore, according to this vehicle behavior control device, when the vehicle behavior stabilization control is performed with the vehicle body turning direction reversed, the vehicle behavior stabilization control is performed on the new turning outer wheel to which the preliminary brake pressure is applied. Therefore, the braking control amount can be generated with good responsiveness. In particular, this vehicle behavior control device can quickly output the preliminary brake pressure even when quick output of the preliminary brake pressure is required, such as when the turn-back steering is sudden steering, and the vehicle has good responsiveness after reversing the turning direction. A braking control amount for behavior stabilization control can be output. Therefore, this vehicle behavior control apparatus can improve the control performance of vehicle behavior stabilization control.

FIG. 1 is a diagram illustrating an example of a vehicle to which a vehicle behavior control device according to the present invention is applied. FIG. 2 is a diagram illustrating an example of a brake actuator. FIG. 3 is a flowchart for explaining a rough flow of expected preliminary brake pressure control by the vehicle behavior control device of the embodiment. FIG. 4 is a flowchart for explaining preliminary brake pressure control by the vehicle behavior control device of the embodiment. FIG. 5 is a flowchart for explaining the continuation of the flowchart of FIG.

  Embodiments of a vehicle behavior control apparatus according to the present invention will be described below in detail with reference to the drawings. The present invention is not limited to the embodiments.

[Example]
A vehicle behavior control apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

  The vehicle behavior control device of this embodiment is prepared as a function of the electronic control unit (ECU) 1 shown in FIG.

[vehicle]
First, an example of a vehicle 10 to which this vehicle behavior control device is applied is shown in FIG.

The vehicle 10 is provided with a steering system that steers the steered wheels W _FL and W _FR by a driver's steering operation. This steering system transmits a steering wheel 21 operated by a driver, a steering shaft 22 connected to the steering wheel 21, and steering torque of the steering shaft 22 to the left and right steering wheels W _FL and W _FR. a steering torque transmission device 23, a steering operation amount by this steering torque transmission device 23 and the steered wheels W _FL, tie rod connecting between the W _FR 24L, and 24R, to detect a steering operation amount of the steering wheel 21 by the driver And a detection device 25. The steering torque transmission device 23 is a so-called rack and pinion mechanism.

  The steering operation amount is, for example, the steering angle δ. The steering operation amount detection device 25 detects the steering angle δ from the rotation angle of the steering shaft 22 and transmits the detection signal to the electronic control device 1. The steering angle δ is detected as a positive value when the steering wheel 21 is steered counterclockwise (left turning direction) from the neutral position (steering center), and is steered clockwise from the steering center. It shall be detected as a negative value. In the electronic control unit 1, the steering angular velocity ωstr is calculated based on the change amount of the steering angle δ over time (ωstr = dδ / dt). Therefore, the steering angular velocity ωstr becomes a positive value when the steering wheel 21 is steered counterclockwise, and becomes a negative value when the steering wheel 21 is steered clockwise.

Here, an example of a steering system in which the steering wheel 21 and the steering wheels W _FL and W _FR are mechanically connected is illustrated, but the steering system is a so-called steer-by-wire system that has no mechanical connection therebetween. It may be a thing.

The vehicle 10 is provided with a power source such as an engine or a motor (not shown). The vehicle 10 travels by transmitting the power of the power source as driving force to the driving wheels. The vehicle 10 is provided with a braking system that stops or decelerates the traveling vehicle 10. The braking system is configured to be able to generate target braking control amounts (target wheel braking torque, target wheel braking force) with individual magnitudes for the respective wheels W _FL , W _FR , W _RL , W _RR . Has been. Here, by utilizing the force of the brake fluid pressure to generate a frictional force between the engaging element, thereby the wheels _{W FL, W FR, W RL} , exemplified for those exerting target braking control amount W _RR.

  First, as shown in FIGS. 1 and 2, this braking system includes a brake pedal 31 operated by a driver and an operation pressure (pedal depression force) accompanying the brake operation input to the brake pedal 31 with a predetermined boost ratio. And a brake booster (brake booster) 32 that doubles the brake pedal pressure multiplied by the brake booster 32 (hereinafter referred to as “master cylinder pressure”). .) And a reservoir tank 34 for storing brake fluid. The brake pedal 31, the brake booster 32, and the like function as a hydraulic pressure generator that generates a brake hydraulic pressure corresponding to the amount of operation of the brake pedal 31 by the driver.

Further, as shown in FIGS. 1 and 2, this braking system includes a hydraulic pressure adjusting device (hereinafter referred to as “brake actuator”) that can adjust the master cylinder pressure for each wheel W _FL , W _FR , W _RL , W _RR. called.) and 35, the brake fluid pressure through the brake actuator 35 (brake hydraulic pressure master cylinder pressure or that pressure master cylinder pressure tone) via the respective fluid pressure line _{36 FL, 36 FR, 36 RL} , 36 RR Brake devices 37 _FL , 37 _FR , 37 _RL , 37 _RR that are supplied and generate braking control amounts (wheel braking torque, wheel braking force) on the respective wheels W _FL , W _FR , W _RL , W _RR are provided. It has been.

The braking devices 37 _FL , 37 _FR , 37 _RL , 37 _{RR apply} a frictional force to a member that rotates integrally with the wheels W _FL , W _FR , W _RL , W _RR, and thereby the wheels W _FL , W _A friction brake device that performs a braking operation while suppressing rotation of _{FR 1} , W _RL , and W _RR , and includes, for example, a disc rotor, a caliper, and the like. The braking devices 37 _FL , 37 _FR , 37 _RL , 37 _RR generate a braking control amount having a magnitude corresponding to the master cylinder pressure sent from the brake actuator 35 or the brake fluid pressure after pressure adjustment. In the following, each braking control amount generated by the master cylinder pressure is referred to as a “master pressure braking control amount”. The braking control amount generated by the brake fluid pressure after adjusting the pressure of the master cylinder is referred to as “pressurized braking control amount”.

The brake actuator 35 of the present embodiment includes a first hydraulic system that transmits brake hydraulic pressure to the right front wheel _WFR and the left rear wheel _WRL , and brake hydraulic pressure to the left front wheel _WFL and the right rear wheel _WRR . And a second hydraulic system that conveys the above. That is, the brake actuator 35 has a structure having a brake hydraulic circuit of X piping. The brake actuator 35 operates in accordance with a control command from the electronic control device 1.

Here, two hydraulic chambers (not shown) are provided inside the master cylinder 33, and the master cylinder pressure is generated in each of the hydraulic chambers. In the first hydraulic system, the brake hydraulic pressure (master cylinder pressure) in one hydraulic chamber of the master cylinder 33 is supplied to the brake actuator 35 via the first hydraulic pipe 38, and the brake actuator 35 is supplied with the brake hydraulic pressure. _Is supplied to the braking devices 37 _FR and 37 _RL of the right front wheel W _FR and the left rear wheel W _{RL while} maintaining or adjusting the pressure of the master cylinder. On the other hand, in the second hydraulic system, the brake hydraulic pressure (master cylinder pressure) in the other hydraulic chamber is supplied to the brake actuator 35 via the second hydraulic pipe 39, and the brake actuator 35 masters the brake hydraulic pressure. The cylinder pressure is maintained or adjusted and supplied to the braking devices 37 _FL and 37 _RR of the left front wheel W _FL and the right rear wheel W _RR .

  The brake actuator 35 is provided with a master cylinder pressure sensor 41 that detects the master cylinder pressure. The master cylinder pressure sensor 41 is provided in any one of the first or second hydraulic pipes 38 and 39 and transmits a detection signal to the electronic control unit 1. Here, the master cylinder pressure sensor 41 is illustrated as being provided in the first hydraulic pipe 38.

The brake actuator 35 includes master cut valves 42 and 43 in the first and second hydraulic systems, respectively. Here, a master cut valve 42 is disposed downstream of the master cylinder pressure sensor 41. Each of these master cut valves 42 and 43 is a so-called normally-open type brake fluid flow adjusting electromagnetic valve, which is in an open state when not energized, and controls the valve opening as the electronic controller 1 is energized. Is executed. Each of the master cut valves 42 and 43 adjusts the pressure of the brake fluid discharged from the pressurizing pumps 69 and 70 described later by controlling the valve opening according to the energization amount, and this is adjusted to the master cylinder 33 side. To open. In addition, the downstream shown in this embodiment represents the downstream side in the flow direction of the brake fluid during pedal operation (that is, the direction toward the braking devices 37 _FL , 37 _FR , 37 _RL , 37 _RR ). And

In the brake actuator 35, the first hydraulic pipe 38 is connected to the connecting passage 44 through the master cut valve 42, while the second hydraulic pipe 39 is connected to the connecting passage 45 through the master cut valve 43. The Then, two branch passages 46 and 47 are connected to the connection passage 44 of the first hydraulic system as if branched from there, and the connection passage 45 of the second hydraulic system is branched therefrom. Two branch passages 48 and 49 are connected. In the first hydraulic circuit, connected to the liquid pressure line _{36 RL} of the right front wheel, each of the branch passages 46 and 47 respectively _{W FR} of the liquid pressure pipe _{36 FR} and the left rear wheel _{W RL.} On the other hand, in the second hydraulic system, is connected to the liquid pressure line _{36 FL} of the liquid pressure pipe _{36 RR} and the left front wheel _{W FL} of the right rear wheel _{W RR} branch passages 48 and 49 each respectively.

Further, the on the branch passages 46, 47, 48, 49, respectively of the brake device _{37 FL, 37 FR, 37 RL} , 37 RR adjustable hydraulic pressure adjusting device the brake fluid pressure of each wheels _{W FL} , W _FR , W _RL , and W _RR . Its respective hydraulic pressure adjusting device, the wheels _{W FL, W FR, W RL} , retention valves provided for each _{W RR} 50, 51, 52, 53 and the liquid pressure discharge passages 54, 55, 56, and 57 under reduced pressure It consists of valves 58, 59, 60, 61. Here, holding valves 50, 51, 52, 53 are provided on the respective branch passages 46, 47, 48, 49, and further, liquids are provided downstream of these holding valves 50, 51, 52, 53. The pressure discharge passages 54, 55, 56 and 57 are connected so as to be branched from the branch passages 46, 47, 48 and 49, respectively. And, on each of the hydraulic pressure discharge passages 54, 55, 56, 57, pressure reducing valves 58, 59, 60, 61 are respectively provided.

  Each of the holding valves 50, 51, 52, 53 is a so-called normally-open electromagnetic valve that is open when not energized and is closed when energized by the electronic control unit 1. . On the other hand, each pressure reducing valve 58, 59, 60, 61 is a so-called normally closed electromagnetic valve, which is in a closed state when not energized, and is opened when energized by the electronic control unit 1.

  In addition, here, the hydraulic pressure discharge passages 62 and 55 that collect the respective hydraulic pressure discharge passages 54 and 55 of the first hydraulic system and the hydraulic pressure discharge passages 56 and 57 of the second hydraulic system are grouped together. And a hydraulic pressure discharge collecting passage 63 is prepared. The respective hydraulic pressure discharge collecting passages 62 and 63 are connected to auxiliary reservoirs 64 and 65, respectively.

  Further, in the first hydraulic system, a pump passage 66 that branches from a branch point between the connecting passage 44 and each of the branch passages 46 and 47 and is connected to the hydraulic discharge collecting passage 62 is provided. Similarly, in the second hydraulic system, a pump passage 67 branched from the branch point between the connecting passage 45 and the branch passages 48 and 49 and connected to the hydraulic discharge collecting passage 63 is provided.

The pump passages 66 and 67 are provided with pressurizing pumps (pressurizing devices) 69 and 70 driven by an electric motor 68, respectively. Each of these pressurizing pumps 69 and 70 discharges the brake fluid toward the respective branch points on the master cut valves 42 and 43 side, and respectively with respect to the branch passages 46 and 47 and the branch passages 48 and 49. To supply the brake fluid pressure. That is, the first hydraulic pressure system pressurizing pump 69 increases the brake hydraulic pressure supplied to the respective braking devices 37 _FR and 37 _RL in order to increase the braking force generated on the right front wheel W _FR and the left rear wheel W _RL . Increase pressure. On the other hand, the pressurizing pump 70 of the second hydraulic pressure system _controls the brake hydraulic pressure supplied to the respective braking devices 37 _FL and 37 _RR in order to increase the braking force generated on the left front wheel W _FL and the right rear wheel W _RR . Increase pressure. The electric motor 68 is driven by power supply from a battery (not shown). In addition, damper chambers 71 and 72 for avoiding pulsation of the brake fluid discharged from the pressurizing pumps 69 and 70 are disposed in the pump passages 66 and 67, respectively.

  The brake actuator 35 is provided with suction passages 73 and 74 that are branched from the first and second hydraulic pipes 38 and 39 and connected to the auxiliary reservoirs 64 and 65, respectively. Reservoir cut check valves 75 and 76 are disposed on the auxiliary reservoirs 64 and 65 side of the respective suction passages 73 and 74.

The operation of the braking system of the present embodiment configured as described above is controlled by the electronic control unit 1 as described above, and ABS (anti-lock braking system) control, VSC (vehicle stability control) control, etc. It can be performed. For example, the electronic control device 1 sets the target braking control amount of the wheel to be controlled based on the operation amount of the driver's brake pedal 31 or a request value from a vehicle behavior control device described later. If the master pressure braking control amount is insufficient with respect to the target braking control amount, the electronic control unit 1 obtains the target brake hydraulic pressure of the wheel to be controlled that can compensate for the shortage. Then, the electronic control unit 1 controls the brake actuator 35 based on the target brake fluid pressure, pressurizes the master cylinder pressure, and sets the pressurization brake control amount that satisfies the target brake control amount. Braking device 37 _FL (37 _FR , 37 _RL , 37 _RR ).

[Vehicle behavior control device]
Further, as described above, a vehicle behavior control device is prepared as one function of the electronic control device 1 of the present embodiment. This vehicle behavior control device performs vehicle behavior stabilization control for stabilizing the behavior of the vehicle 10 during turning.

  Specifically, this vehicle behavior control device controls the brake actuator 35 during turning, and generates a braking control amount (wheel braking torque, wheel braking force) on at least one of the front and rear turning outer wheels. Stabilize the behavior of the vehicle 10 inside. For example, this vehicle behavior control device generates a yaw moment in the opposite direction to the yaw moment acting on the vehicle body in accordance with the turning operation by the braking control on the turning outer wheel. By performing oversteer suppression control (so-called spin control), a vehicle body that exhibits an oversteer tendency is brought closer to neutral steer. In the spin control, the target braking control amount FFout0 is generated in the front turning outer wheel. In the spin control, the target braking control amount FRout0 may be generated also in the rear turning outer wheel. In this case, the target braking control amount FFout0 of the front turning outer wheel is set larger than the target braking control amount FRout0 of the rear turning outer wheel.

  The braking control for the turning outer wheel in the spin control is executed according to the magnitude of the roll moment and the yaw moment in the turning operation of the vehicle 10 when the driver performs the steering operation. Here, the driver performs the first steering operation starting from the steering center, and performs the second steering operation beyond the steering center opposite to the first steering operation following the steering operation. There is a case in which a turn-back steering is performed in which the steering operation is performed twice or more alternately with respect to the steering center. For example, the scene in which the turn-back steering is performed corresponds to a scene in which the vehicle travels on a turning circuit in which the turning direction is alternately alternated from left to right, a scene in which slalom travel is performed, and the like. Then, when this turning-back steering is performed, in the vehicle 10, when the steering operation after the second time at the turning-back steering is performed, an excessive roll moment and yaw moment are applied to the vehicle body than at the time of the first steering operation. There is a possibility of acting. For this reason, the spin control may be executed when the driver performs the first steering operation with the steering center as a starting point, but when the second or subsequent steering operation is performed during the reverse steering. Likely to be executed. For example, the vehicle behavior control device performs an operation that exceeds the steering center in the opposite direction by the reverse steering, and when the turning direction of the vehicle body is reversed, an excessive roll moment is applied to the vehicle body. Control is performed so that the yaw moment does not act. In that case, a braking control amount is generated in at least one of the new front and rear turning outer wheels, and a yaw moment in the opposite direction to the yaw moment is generated in the vehicle body, thereby suppressing the excessive roll amount. It is possible to turn while keeping 10 behaviors stable.

  Here, for example, when the steering angle δ of the steering wheel 21 in the steering operation immediately before the reverse steering is large and the steering angular velocity ωstr at the time of the reverse steering from the previous steering operation is high, The roll moment or yaw moment acting on the vehicle body by reversing the turning direction is smaller than the case where the steering angle δ of the previous steering operation is small and the steering angular velocity ωstr of the reverse steering from the previous steering operation is slow. growing. When the steering angle δ is equal to or greater than a predetermined value and the steering angular velocity ωstr is equal to or greater than a predetermined value, the yaw moment to be generated by the braking control amount FFout of the outer turning wheel is large. There is a possibility that braking control amounts FFout and FRout for spin control must be generated in the turning outer wheel. On the other hand, when the steering angle δ is smaller than the predetermined value and the steering angular velocity ωstr is slower than the predetermined value, the steering angle δ is larger than the predetermined value and the steering angular velocity ωstr is larger than the predetermined value. Since the yaw moment to be generated with the braking control amount of the turning outer wheel is small, the braking control amount FFout for spin control only needs to be generated only for the front turning outer wheel. Each of the predetermined values is a threshold value that varies depending on the position of the center of gravity of the vehicle, for example, and varies depending on the vehicle type.

  From this, this vehicle behavior control device is capable of generating the braking control amount with good responsiveness so that the control target wheel that newly becomes the turning outer wheel with the reversal of the turning direction can generate the braking control amount before the turning inner wheel. It is preferable to perform preliminary brake pressure control in the state. The preliminary brake pressure is applied to at least one of the inner turning wheels before and after the condition that the braking control amount is generated in each of the outer turning wheels.

  Specifically, when it is necessary to generate braking control amounts FFout and FRout for spin control on the respective turning outer wheels on the front and rear sides, in order to perform spin control with high responsiveness even in a sudden turn-back steering, It is desirable to apply the preliminary brake pressure while the turning outer wheel is still turning inner wheel by the previous steering operation. However, at the time when the preliminary brake pressure control is started, whether the reverse steering operation performed after the previous steering operation is the reverse steering beyond the steering center or the returning operation to the steering center. It is difficult to accurately determine whether it is. In the spin control, the vehicle behavior can be sufficiently stabilized only by generating the braking control amount FFout for the spin control in the front turning outer wheel, and the braking for the spin control is performed up to the rear turning outer wheel. The frequency with which the excessive roll moment and yaw moment that generate the control amount FRout are applied is low. For this reason, if the preliminary brake pressure is applied even to the rear turning outer wheel that is the frequency of the control object, the fuel consumption is deteriorated due to the driving of the pressurizing pump 69 (70), which is not preferable.

  Therefore, in this embodiment, when the braking control amount FRout for spin control is currently generated in the rear turning outer wheel, the execution of the spin control similar to the current spin control is performed in the turning direction accompanying the reverse steering. The braking control amounts FFout and FRout for spin control may have to be generated on the front and rear turning outer wheels, but the reverse steering operation is not a reverse steering but a return steering. In view of the deterioration in fuel consumption when the operation is performed, the preliminary brake pressure is applied only to the current front turning inner wheel that becomes the front turning outer wheel when the turning direction is reversed. In other words, the vehicle behavior control device of this embodiment does not know whether or not the rearward turning direction of the vehicle body actually reverses when a braking control amount FRout for spin control is generated on the rear turning outer wheel. However, taking into account the deterioration of fuel consumption, it is expected that the turning direction will be reversed by turning-back steering, and preliminary brake pressure control is started on the current turning inner wheel. The expectation that the turning direction is reversed is triggered by the driver's turning-back steering, that is, the reverse steering operation.

  The reserve brake pressure (hereinafter, also referred to as “predicted reserve brake pressure”) means, for example, a brake fluid pressure that does not clearly decrease the rotation speed of the wheel to be controlled, in other words, a brake fluid pressure that is larger than that. When applied, the brake fluid pressure can generate a braking control amount corresponding to the brake fluid pressure with good responsiveness. The estimated preliminary brake pressure is output by controlling the brake actuator 35.

  For example, as shown in the flowchart of FIG. 3, the vehicle behavior control device first determines whether or not the execution permission condition for the spin control is satisfied (step ST1). This determination determines whether or not it is necessary to execute control for suppressing oversteer, and may be applied to a well-known execution permission condition in this control. For example, the vehicle behavior control apparatus determines that the execution permission condition for spin control is satisfied when the yaw moment is greater than a predetermined threshold.

If the execution permission condition for spin control is satisfied, the vehicle behavior control device can control the target braking control amount (target wheel braking torque, target wheel) of each wheel W _FL , W _FR , W _RL , W _RR for spin control. (Braking force) is set (step ST2). In the spin control, as described above, the braking force is generated in at least one of the front and rear turning outer wheels. Therefore, the target braking control of the control target wheel (at least one of the front and rear turning outer wheels) that generates the braking force is performed. The amount is set to a positive value, and the target braking control amount of the turning inner wheel before and after generating no braking force is set to zero. Here, the target braking control amount FFout0 of the front turning outer wheel is A (> 0), the target braking control amount FRout0 of the rear turning outer wheel is B (> 0), and the target braking control amount FFin0 of the front turning inner wheel is 0. The target braking control amount FRin0 for the rear turning inner wheel is set to zero.

  The vehicle behavior control device determines whether or not the braking control amount FRout is also generated in the rear turning outer wheel with the execution of the spin control (FRout> 0?) (Step ST3). Here, since the target braking control amount FRout0 of the rear turning outer wheel is set to B (> 0), the vehicle behavior control device sets the preliminary brake pressure control start flag Fs when the braking control amount FRout is generated ( Fs = ON) (step ST4). As a result, the vehicle behavior control device applies a prospective preliminary brake pressure to the front turning inner wheel that may be the next turning outer wheel.

  On the other hand, this vehicle behavior control apparatus lowers the preliminary brake pressure control start flag Fs (Fs = OFF) (step ST5) unless the braking control amount FRout is generated in the rear turning outer wheel.

  Hereinafter, a specific example of the preliminary brake pressure control will be described.

  The vehicle behavior control device sets the preliminary brake pressure control mode M to the prospective preliminary brake pressure control mode M1 or the normal preliminary brake pressure control mode M3, and executes the preliminary brake pressure control in any one of the control modes. Further, the vehicle behavior control device sets the preliminary brake pressure control mode M to the preliminary brake pressure off mode M1off when the expected preliminary brake pressure in the expected preliminary brake pressure control mode M1 is not applied. Further, the vehicle behavior control device sets the preliminary brake pressure control mode M to the preliminary brake pressure when the preliminary brake pressure in the normal preliminary brake pressure control mode M3 (hereinafter also referred to as “normal preliminary brake pressure”) is not applied. Set to off mode M3off.

  The prospective preliminary brake pressure control mode M1 is the control mode of the prospective preliminary brake pressure described above with reference to the flowchart of FIG. 3, and is particularly suitable for the preliminary brake pressure control and spin when the quick turnback steering is performed. This is to increase the control response of the control. Therefore, in this prospective preliminary brake pressure control mode M1, the magnitude of the prospective preliminary brake pressure is such that when the brake fluid pressure is increased in a state where the prospective preliminary brake pressure is applied, the braking control amount is generated immediately. Is set. In the prospective preliminary brake pressure control mode M1, when the braking control amount FRout for spin control is generated in the rear turning outer wheel and when it is predicted that the turn-back steering is performed, A prospective brake pressure is applied to the front turning inner wheel together with the output of the braking control amount FRout. However, the probable reverse steering includes not only quick reverse steering but also reverse steering that is performed more slowly than this.

As the anticipated preliminary brake pressure control mode M1, and potential right front wheel control mode M1FR applying a anticipated preliminary brake pressure to the braking device _{37 FR} of the right front wheel _{W FR,} anticipated preliminary brake pressure to the braking device _{37 FL} of the left front wheel _{W FL} A prospective left front wheel control mode M1FL is applied.

The vehicle behavior control apparatus, when setting the prospective right front wheel control mode M1FR, applies the anticipated preliminary brake pressure to the right front wheel W _FR by controlling the brake actuator 35. At that time, the vehicle behavior control device causes the brake actuator 35 to close the master cut valve 42 and the pressure reducing valve 58 related to the right front wheel _WFR and to open the holding valve 50, and the expected preliminary brake pressure is set to the right front wheel. The electric motor 68 and the pressure pump 69 are driven so as to be applied to the brake device 37 _FR of the W _FR . In this case, the brake actuator 35 is configured such that the master cut valve 43, the holding valves 51, 52, 53 and the pressure reducing valves 59, 60, 61 related to the other wheels W _FL , W _RL , W _RR are closed, and the other wheels W Control is performed so that the braking control amount does not _act on _FL , _WRL , and _WRR (that is, the prospective preliminary brake pressure is not applied).

Also, the vehicle behavior control apparatus, when setting the estimated left front wheel control mode M1FL, applies the anticipated preliminary brake pressure to the left front wheel W _FL and controls the brake actuator 35. At that time, the vehicle behavior control device causes the brake actuator 35 to close the master cut valve 43 and the pressure reducing valve 61 related to the left front wheel _WFL and to open the holding valve 53, and the expected preliminary brake pressure is set to the left front wheel. The electric motor 68 and the pressurizing pump 70 are driven so as to be applied to the W _FL braking force generating means 37 _FL . Brake actuator 35 at that time, other wheels _{W FR,} W _RL, the master cut valve 42 and the holding valves 50, 51 and 52 and the pressure reducing valve 58, 59, 60 according to _{W RR} is closed, the other wheels W Control is performed so that braking force does not _act on _{FR 1} , W _RL , and W _RR (a prospective preliminary brake pressure is not applied).

  On the other hand, the normal preliminary brake pressure control mode M3 corresponds to the conventional preliminary brake pressure control mode. For example, a preliminary brake pressure lower than the predicted preliminary brake pressure generated in the predicted preliminary brake pressure control mode M1 is applied. This is a control mode that can be used. In this normal preliminary brake pressure control mode M3, a master valve closing mode M3a and a motor drive mode M3b are prepared.

  In the master valve closing mode M3a, the master cut valve 42 (43) and the pressure reducing valve 58 (59, 60, 61) of the control target wheel to which normal preliminary brake pressure is applied are closed, and the control valve 50 of the control target wheel is maintained. (51, 52, 53) is a mode in which normal preliminary brake pressure is applied to the wheel to be controlled by driving the electric motor 68 and the pressure pump 70 by opening the valve (51, 52, 53).

  In the motor drive mode M3b, the master cut valve 42 (43) of the wheel to be controlled is opened with respect to the master valve close mode M3a, and a normal preliminary brake pressure that is weaker than that in the master valve close mode M3a is generated. .

Also, the vehicle behavior control device, preliminary brake pressure off mode M1off, when setting the M3off, braking force does not work to control the brake actuator 35 the wheels _{W FL, W FR, W RL} , W RR ( (Preliminary brake pressure is not applied). At that time, the vehicle behavior control device controls the brake actuator 35 so that at least the electric motor 68 and the pressure pumps 69 and 70 are not driven.

  Hereinafter, a specific example of the arithmetic processing operation (preliminary brake pressure control) of the vehicle behavior control device of this embodiment will be described in detail based on the flowcharts of FIGS. 4 and 5.

  First, as shown in the flowchart of FIG. 4, the vehicle behavior control device determines whether or not the execution of the preliminary brake pressure control may be permitted (step ST10). The determination in step ST10 is to see whether or not there is an obstacle to the execution of the preliminary brake pressure control. For example, in this step ST10, when the braking system and the sensor necessary for ABS control, VSC control, etc. are functioning normally, “permission of preliminary brake pressure control” is permitted. Make a decision.

  If the execution of the preliminary brake pressure control is not permitted, the vehicle behavior control device sets the preliminary brake pressure control mode M to the preliminary brake pressure off mode M1off (step ST15). On the other hand, if execution of the preliminary brake pressure control is permitted, the vehicle behavior control device determines whether or not the preliminary brake pressure control mode M is set to the preliminary brake pressure off mode M1off (step ST20). . In the initial state (the state in which the preliminary brake pressure control has not been executed once after the ignition is turned on), the preliminary brake pressure control mode M is set to the preliminary brake pressure off mode M1off.

  When the preliminary brake pressure off mode M1off is not set, the vehicle behavior control device proceeds to step ST70 described later. On the other hand, when the preliminary brake pressure off mode M1off is set, the vehicle behavior control device determines whether or not the spin control execution permission condition is satisfied, as in step ST1 described above. (Step ST25).

If the execution permission condition for the spin control is not satisfied, the vehicle behavior control device proceeds to step ST70 described later. On the other hand, in the vehicle behavior control device, if the execution permission condition for the spin control is satisfied, the wheels W _FL , W _FR , W _RL , W for the spin control are performed as in step ST2 described above. A target braking control amount for _RR is set (step ST30). Then, the vehicle behavior control device determines whether or not the braking control amount FRout is generated in the rear turning outer wheel with the execution of the spin control (FRout> 0?) (Step ST35).

  If the vehicle behavior control device generates the braking control amount FRout, the vehicle 10 is turning right and whether or not the steering angular velocity ωstr at that time is a positive value, that is, during turning right. It is determined whether or not the steering wheel 21 is steered in the reverse direction (counterclockwise direction) (step ST40).

When the vehicle is turning right and the steering angular velocity ωstr is a positive value, the vehicle behavior control device sets the preliminary brake pressure control mode M to the prospective right front wheel control mode M1FR and is the current turning inner wheel. applying a anticipated preliminary brake pressure to the right front wheel _{W FR} (step ST45). In other words, when a steering operation in the opposite direction to the turning direction is performed during a right turn, the vehicle behavior control device determines whether the reverse steering operation is a return operation to the steering center or a turn over the steering center. difficult to determine whether a steering, but is expected to be crosscut steering, adding anticipated preliminary brake pressure to the right front wheel W _FR to become the next front turning outer wheel with the turning direction reversal by the crosscut steering. Thereafter, the vehicle behavior control device proceeds to step ST70 described later.

  On the other hand, when the vehicle is turning right and the steering angular velocity ωstr is not a positive value, the vehicle behavior control device determines whether the vehicle 10 is turning left and the steering angular velocity ωstr at that time is a negative value. It is determined whether or not the steering wheel 21 is steered in the reverse direction (clockwise direction) during the left turn (step ST50).

This vehicle behavior control device sets the preliminary brake pressure control mode M to the prospective left front wheel control mode M1FL when turning left and the steering angular velocity ωstr is a negative value, and the left front wheel W which is the current front turning inner wheel W1. _Expected preliminary brake pressure is applied to _FL (step ST55). That is, when a steering operation in the direction opposite to the turning direction is performed during the left turn, the vehicle behavior control device again determines whether the steering operation in the opposite direction is a return operation to the steering center. difficult to determine whether the a countersteering steering exceeding but is expected to be crosscut steering, adding anticipated preliminary brake pressure to the left front wheel W _FL to become the next front turning outer wheel with the reversal of the turning direction by the turning back steering. Thereafter, the vehicle behavior control device proceeds to step ST70 described later.

  If a negative determination is made in step ST50, it is clear that the driver is not turning back, so the vehicle behavior control device proceeds to step ST70 described later.

  On the other hand, when the braking control amount FRout for spin control is not generated in the rear turning outer wheel, the vehicle behavior control device determines that the absolute value of the detected steering angle δ is greater than a predetermined threshold Thδ (> 0). Whether the absolute value of the calculated steering angular velocity ωstr is smaller than a predetermined threshold Thωstr2 (> 0), or is the absolute value of the calculated yaw angular acceleration αy smaller than a predetermined threshold Thαy2 (> 0) (Step ST60). In this step ST60, when the absolute value of the steering angle δ is smaller than the predetermined threshold Thδ and the absolute value of the steering angular velocity ωstr is smaller than the predetermined threshold Thωstr2, or the absolute value of the steering angle δ is larger than the predetermined threshold Thδ. Is smaller and the absolute value of the yaw angular acceleration αy is smaller than the predetermined threshold Thαy2, a positive determination is made, and a negative determination is made otherwise.

  When an affirmative determination is made in step ST60, it is determined that the operation is to return the steering wheel 21 to the steering center. For this reason, the vehicle behavior control apparatus at this time sets the preliminary brake pressure control mode M to the preliminary brake pressure off mode M1off (step ST65), and proceeds to step ST70 described later. On the other hand, when a negative determination is made in step ST60, for example, the steering angular velocity ωstr is fast and there is a possibility that the turning-back steering is performed, so the process proceeds to step ST70 without setting the preliminary brake pressure off mode M1off.

  After finishing the arithmetic processing in the flowchart of FIG. 4, the vehicle behavior control device does not have the previous preliminary brake pressure control mode M2 in the preliminary brake pressure off mode M1off and the current preliminary brake as shown in the flowchart in FIG. 5. It is determined whether the pressure control mode M is the preliminary brake pressure off mode M1off (step ST70). In this step ST70, if the previous preliminary brake pressure control mode M2 is the prospective right front wheel control mode M1FR or the prospective left front wheel control mode M1FL, and the current preliminary brake pressure control mode M is the preliminary brake pressure off mode M1off. An affirmative determination is made, otherwise a negative determination is made. For example, in this step ST70, when the prospective preliminary brake pressure control mode M1 is set for the first time (that is, when the previous preliminary brake pressure control mode M2 has not been determined), or the expected preliminary brake pressure control is continuing (previous time). When the preliminary brake pressure control mode M2 and the current preliminary brake pressure control mode M are in the prospective preliminary brake pressure control mode M1), a negative determination is made.

  The case where an affirmative determination is made in step ST70 is a case where the prospective preliminary brake pressure control is executed once and it can be determined that the next steering operation is a return operation of the steering wheel 21 to the steering center. For this reason, the vehicle behavior control apparatus determines that if the previous preliminary brake pressure control mode M2 is not the preliminary brake pressure off mode M1off and the current preliminary brake pressure control mode M is the preliminary brake pressure off mode M1off, Brake pressure control one-time operation flag (hereinafter referred to as “expected operation flag”) F1 is set (F1 = ON) (step ST75). The prospective operation flag F1 indicates that the execution of the prospective preliminary brake pressure control is finished once.

  Subsequently, after making a negative determination in step ST70 or setting the expected operation flag F1 in step ST75, the vehicle behavior control apparatus determines whether or not the expected operation flag F1 is set (step ST80). ). In this step ST80, an affirmative determination is made if the step ST75 has been passed, and if a negative determination is made in the step ST70, for example, if the expected right front wheel control mode M1FR or the expected left front wheel control mode M1FL is set, A negative determination is made.

  When the expected operation flag F1 is set, the vehicle behavior control device counts the time C1 during which the expected operation flag F1 is set (hereinafter referred to as “expected operation flag elapsed time”) (C1 = C1 + 1) (step ST85).

  Subsequently, after making a negative determination in step ST80 or counting the expected operation flag elapsed time C1 in step ST85, the vehicle behavior control device determines whether the expected operation flag elapsed time C1 has exceeded a predetermined time T1. Is determined (step ST90). The predetermined time T1 is the maximum time during which the prospective preliminary brake pressure control is prohibited. That is, the determination of step ST90 is that the estimated preliminary brake pressure control is executed once and then the estimated operation flag elapsed time C1 is set to the predetermined time T1 when the return operation of the steering wheel 21 to the steering center is performed. This is to prohibit the execution of the prospective preliminary brake pressure control until the value exceeds. In step ST90, not only when the expected operation flag elapsed time C1 counted in step ST85 does not exceed the predetermined time T1, but also when it is determined in step ST80 that the expected operation flag F1 is not set, for example, A negative determination is also made when the preliminary brake pressure control mode M is set to the prospective right front wheel control mode M1FR or the prospective left front wheel control mode M1FL.

  When the expected operation flag elapsed time C1 exceeds the predetermined time T1, the vehicle behavior control device lowers the expected operation flag F1 (F1 = OFF) and resets the expected operation flag elapsed time C1 (C1 = 0) (step ST95). ). Thereby, when the turn-back steering is performed again after the return operation of the steering wheel 21 to the steering center, the prospective preliminary brake pressure control that has been prohibited for a predetermined time (= predetermined time T1) can be executed again. .

  Subsequently, the vehicle behavior control device applies the current preliminary brake pressure control mode M as the previous preliminary brake pressure control mode M2 after the negative determination in step ST90 or after the step ST95 (M2 ← M). (Step ST100).

  Then, the vehicle behavior control device determines whether the newly set previous preliminary brake pressure control mode M2 is not the preliminary brake pressure off mode M1off and whether the prospective operation flag F1 is lowered (step). ST105).

  The vehicle behavior control device sets the preliminary brake pressure control mode M to the master valve closing mode M3a when the previous preliminary brake pressure control mode M2 is the preliminary brake pressure off mode M1off and the expected operation flag F1 is lowered. Then, the normal preliminary brake pressure in the master valve closing mode M3a is applied to at least one of the current turning inner and rear wheels (step ST110).

  On the other hand, when a negative determination is made in step ST105, the vehicle behavior control device determines whether or not a normal preliminary brake pressure control one-time operation flag (hereinafter referred to as “normal operation flag”) F2 is set. A determination is made (step ST115). The normal operation flag F2 indicates that the execution of the normal preliminary brake pressure control is completed once, and is set, for example, when the normal preliminary brake pressure control is completed.

  When the normal operation flag F2 is set, the vehicle behavior control device counts the time C2 during which the normal operation flag F2 is set (hereinafter referred to as “normal operation flag elapsed time”) (C2 = C2 + 1) (step ST120). And this vehicle behavior control apparatus determines whether the normal operation flag elapsed time C2 is shorter than predetermined time T2 (step ST125). The predetermined time T2 is the maximum time during which the execution of the normal preliminary brake pressure control is continued.

  When the normal operation flag elapsed time C2 is shorter than the predetermined time T2, the vehicle behavior control device proceeds to step ST110, and the master valve closing mode M3a capable of applying a high normal preliminary brake pressure in the normal preliminary brake pressure control mode M3. Is set to the preliminary brake pressure control mode M, and the normal preliminary brake pressure in the master valve closing mode M3a is applied to at least one of the previous and following turning inner wheels.

  On the other hand, when the normal operation flag elapsed time C2 becomes equal to or longer than the predetermined time T2, the vehicle behavior control device sets the preliminary brake pressure control mode to the motor drive mode M3b in which the normal preliminary brake pressure is lower than the master valve closing mode M3a. M is set, and the normal preliminary brake pressure in the motor drive mode M3b is applied to at least one of the current front and rear turning inner wheels (step ST130).

  On the other hand, when the normal operation flag F2 is not set, the vehicle behavior control device sets the preliminary brake pressure control mode M to the preliminary brake pressure off mode M3off (step ST135).

  This vehicle behavior control device is used for a vehicle behavior that requires spin control when the driver performs a steering operation beyond the steering center in the opposite direction and the turning direction of the vehicle body is reversed. A target braking control amount for spin control can be generated with high responsiveness to a new turning outer wheel to which brake pressure is applied. In particular, in this vehicle behavior control device, when the braking control of the rear turning outer wheel for the spin control in the current turning operation is started, the front turning that may become the next turning outer wheel by reversing the turning direction is started. Apply prospective preliminary brake pressure to the inner ring. In other words, in this vehicle behavior control device, the estimated preliminary brake pressure can be applied to the front turning inner wheel before the turning direction of the vehicle body is actually reversed. Therefore, according to this vehicle behavior control device, even if the reverse steering from the current turning state requires quick preliminary brake pressure output such as sudden steering, the vehicle body is in the next reverse direction. The preliminary brake pressure can be applied quickly before moving to the turning motion. Therefore, according to this vehicle behavior control device, the target braking control amount can be generated with good responsiveness to the new front turning outer wheel after the turning direction is reversed, so that the control performance of the spin control can be improved. .

  Further, in this vehicle behavior control device, the behavior of the vehicle accompanying the steering operation in the reverse direction of the driver is not observed, and whether the steering operation in the reverse direction is a turnback steering exceeding the steering center is a return operation to the steering center. Since it is not clear whether the preliminary brake pressure control is performed on the front turning inner wheel, the preliminary brake pressure control may not be necessary. However, in spin control, for example, if it is determined that the amount of steering operation (steering angular velocity, etc.) of the driver in the reverse direction does not correspond to reverse steering, the rear turning outer wheel is used for spin control. The braking control amount FRout that has been generated is set to zero. Accordingly, in this case, “NO” is determined in step ST35, and “YES” is determined in step ST60. Therefore, the preliminary brake pressure control mode M is set to the preliminary brake pressure off mode M1off, and the front turning inner wheel is set. Expected preliminary brake pressure control is canceled. Therefore, according to this vehicle behavior control device, when the estimated preliminary brake pressure control is unnecessary, the estimated preliminary brake pressure control is canceled immediately after the estimated preliminary brake pressure is applied, and the unnecessary estimated preliminary brake pressure control is shortened. Since it can be completed in time, the above-described control responsiveness when expected preliminary brake pressure control is required can be ensured, and for example, deterioration of fuel consumption when not required can be suppressed to a low level.

  Further, in this vehicle behavior control device, since the frequency of generating a braking control amount for spin control on the rear turning outer wheel is low, prospective preliminary brake pressure control is performed on the rear turning inner wheel before turning direction is reversed. First, preliminary brake pressure control is performed only on the front turning inner wheel. Therefore, according to this vehicle behavior control device, it is possible to suppress an increase in the operating frequency of the brake actuator 35 for unnecessary prospective preliminary brake pressure control. When the frequency of generating the braking control amount for the spin control is high for the rear turning outer wheel, the estimated preliminary brake pressure control may be performed for the front and rear turning inner wheels.

1 Electronic control unit (ECU)
DESCRIPTION OF SYMBOLS 10 Vehicle 21 Steering wheel 25 Steering operation amount detection device 35 Brake actuator _37FL , _37FR , _37RL , _37RR braking device _WFL , _WFR , _WRL , _WRR wheel

Claims (3)

  When performing vehicle behavior stabilization control that stabilizes the behavior of the vehicle by generating a braking control amount on at least one of the front and rear turning outer wheels, a condition for generating the braking control amount on the front and rear turning outer wheels is satisfied. In this case, the vehicle behavior control device is characterized in that a preliminary brake pressure is applied to at least one of the front and rear turning inner wheels.   2. The vehicle behavior control device according to claim 1, wherein the application of the preliminary brake pressure is executed when a steering operation in the direction opposite to the current turning operation of the vehicle is detected during the execution of the vehicle behavior stabilization control.   The vehicle behavior control device according to claim 1 or 2, wherein when the vehicle behavior stabilization control is oversteer suppression control, the preliminary brake pressure is applied to a front turning inner wheel.

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