JP5018623B2 - Vehicle stabilization control device - Google Patents

Description

  The present invention relates to a vehicle stabilization control device. In particular, the present invention relates to a vehicle stabilization control device that can ensure stability during braking of the vehicle.

  In the conventional vehicle stabilization control device, when the motion state of the running vehicle is detected by a sensor and the behavior of the running vehicle is determined to be unstable from the detection result of the sensor, the vehicle stabilization is performed. Control is in progress. For example, in the vehicle behavior control apparatus described in Patent Literature 1, the yaw rate of the vehicle is detected by a yaw rate sensor, and the magnitude of the deviation between the detected value of the yaw rate sensor and the target yaw rate is greater than the control start determination threshold. In this case, the vehicle behavior stabilization control is started. Further, in the vehicle behavior control device described in Patent Document 1, when the detection value of the yaw rate sensor is large, the control start determination threshold is increased or the yaw rate is compared with the case where the detection value of the yaw rate sensor is small. The value detected by the sensor is corrected to be large, or the yaw rate deviation is corrected to be small. As a result, when the detection value at the yaw rate sensor is large, it is difficult to determine that the magnitude of the deviation between the detection value at the yaw rate sensor and the target yaw rate is larger than the control start determination threshold value, so that the gain is reduced in the yaw rate sensor It is possible to suppress erroneous determination that stabilization control is necessary when an abnormality such as the above occurs.

  In addition, when the vehicle is braked, the behavior characteristics of the vehicle are likely to change due to changes in the running state of the vehicle, road surface conditions, and the like. Therefore, the conventional vehicle stabilization control device ensures the stability of the behavior during braking. There is something. For example, in the turning behavior control device for a vehicle described in Patent Document 2, a turning behavior target value is set from the steering operation by the driver and the vehicle speed, and each wheel speed is independently set based on the set turning behavior target value. I have control. Thus, by independently controlling each wheel speed, each wheel speed can be matched with the target wheel speed even when the friction coefficient of the road surface is low. The turning behavior can be obtained.

  In addition, in the vehicle braking behavior compensation device described in Patent Document 3, the horizontal plane motion that should occur in the vehicle is estimated based on the steering amount by the driver, the braking input, and the vehicle horizontal plane motion transmission characteristics. Based on the braking force difference set by setting the braking force difference between the left and right wheels based on this, braking is performed. Thereby, it is possible to perform braking with a desired behavior even in a situation where there is a change in behavior characteristics during braking of the vehicle.

JP 2005-289244 A JP 7-228235 A JP-A-4-63756

  However, a sensor that detects a vehicle state quantity such as a yaw rate sensor may cause an error in the output value because the output value fluctuates due to temperature drift or the output value changes depending on the slope of the road surface. Here, in the conventional vehicle stabilization control device, when the vehicle becomes unstable during braking, the current vehicle state quantity is changed to the vehicle motion as in the vehicle behavior control device described in Patent Document 1. Obtain from the output value from the sensor that detects the state, use the difference between the acquired current vehicle state amount and the target vehicle state amount, perform left and right braking force distribution and steering cooperative control to reduce the difference Yes.

  However, since the sensor for detecting the vehicle state quantity may cause an error in the output value as described above, in order to suppress the control based on the incorrect output value, a dead zone is provided for the output value of the sensor. There are many cases. For this reason, in such a vehicle stabilization control device, the stabilization control of the vehicle behavior is not performed in the dead zone region, and the difference between the current vehicle state quantity and the target vehicle state quantity is small. Can no longer allow control interventions.

  As described above, in the conventional vehicle stabilization control device, the dead zone for the current vehicle state quantity is set. However, if the stabilization control of the vehicle behavior is not performed in the dead zone region, When the stabilization control is performed due to the instability and the difference in the vehicle state quantity becoming large, the timing of the control intervention may be delayed. In addition, when the vehicle behavior stabilization control is not performed in the dead zone region, the stabilization control is not performed when the difference in the vehicle state quantity is small, but the vehicle behavior during braking is not controlled. Even if the vehicle becomes unstable to the extent that it does not intervene, the vehicle occupant may feel the behavior and feel uncomfortable.

  As described above, the conventional vehicle stabilization control device does not perform the stabilization control of the vehicle behavior in the vehicle state region where the behavior of the vehicle becomes slightly unstable. Although the vehicle occupant sometimes feels uncomfortable, an error occurs in the output value as described above in the sensor that detects the vehicle state quantity. To suppress these, the stabilization control is performed in this vehicle state region. It was very difficult to do.

  The present invention has been made in view of the above, and an object of the present invention is to provide a vehicle stabilization control device that can ensure the stability of a vehicle in a wider vehicle state region.

  In order to solve the above-described problems and achieve the object, a vehicle stabilization control device according to the present invention includes an actual vehicle state quantity acquisition unit that acquires an actual vehicle state quantity that is an actual vehicle state quantity of a vehicle, a target When the target vehicle state quantity deriving means for deriving the target vehicle state quantity that is a vehicle state quantity becomes different from the actual vehicle state quantity and the target vehicle state quantity, Vehicle state quantity stabilization control means for performing vehicle state quantity stabilization control, which is control for bringing the actual vehicle state quantity close to the target vehicle state quantity, and an actual wheel that is an actual wheel speed difference between the left and right wheels of the vehicle An actual wheel speed difference obtaining unit for obtaining a speed difference, a target wheel speed difference deriving unit for deriving a target wheel speed difference that is a target wheel speed difference, and the actual wheel speed difference deviating from the target wheel speed difference. If the vehicle motion control By performing wheel speed difference stabilization control, which is a control for bringing the actual wheel speed difference closer to the target wheel speed difference, and when the actual vehicle state quantity and the target vehicle state quantity deviate, Wheel speed difference stabilization control means for ending the wheel speed difference stabilization control.

  In the present invention, since the vehicle state quantity stabilization control is performed when the actual vehicle state quantity and the target vehicle state quantity are compared and both are deviated, the behavior is stabilized when the behavior of the vehicle becomes unstable. Can be made. Further, the actual wheel speed difference acquisition means acquires the actual wheel speed difference and derives the target wheel speed difference, which is the target wheel speed difference. Wheel speed difference stabilization control, which is a control approaching the speed difference, is performed. The vehicle state quantity is an amount that represents the state of the vehicle when the behavior of the vehicle actually changes. However, the wheel speed difference occurs not only when the behavior of the vehicle changes but also when there is an indication of a change. . For this reason, when the actual wheel speed difference that is the actual wheel speed difference between the left and right wheels is acquired when the vehicle is traveling, and the acquired actual wheel speed difference deviates from the target wheel speed difference, the behavior of the vehicle is It can be determined that this is a sign of instability. Therefore, in this case, the vehicle behavior can be stabilized by performing wheel speed difference stabilization control, which is control for bringing the actual wheel speed difference closer to the target wheel speed difference.

  As described above, when the actual vehicle state quantity deviates from the target vehicle state quantity, the vehicle state quantity stabilization control is performed, and when the actual wheel speed difference deviates from the target wheel speed difference, the wheel speed difference stabilization is performed. In addition to the vehicle state area where the behavior of the vehicle can be judged by the vehicle state quantity, the vehicle state area before the change appears in the vehicle state quantity, that is, the vehicle where the behavior change cannot be judged by the vehicle state quantity. Even in the state region, the behavior of the vehicle can be stabilized. As a result, the stability of the vehicle can be ensured in a wider vehicle state region.

  The vehicle stabilization control device according to the present invention further includes an estimated vehicle state quantity estimating means for estimating an estimated vehicle state quantity based on the actual wheel speed difference in the above invention, and the wheel speed difference stabilization When the estimated vehicle state quantity deviates from the target vehicle state quantity, the control control means causes the estimated vehicle state quantity to approach the target vehicle state quantity by performing the wheel speed difference stabilization control. And

  In the present invention, the estimated vehicle state quantity is estimated based on the actual wheel speed difference, and the wheel speed difference stabilization control is performed when the estimated estimated vehicle state quantity deviates from the target vehicle state quantity. That is, when determining whether or not the behavior of the vehicle is unstable, the estimated vehicle state quantity or the actual vehicle state quantity is compared with the target vehicle state quantity. Thereby, in any vehicle state region, the state of the vehicle is determined based on the vehicle state amount, so that it can be easily determined when determining the behavior of the vehicle. As a result, the stability of the vehicle can be ensured more easily in a wide vehicle state region.

  In the vehicle stabilization control device according to the present invention, in the above invention, the vehicle state quantity stabilization control and the wheel speed difference stabilization control are performed when a braking operation is performed by a driver of the vehicle. It is characterized by that.

  In the present invention, the vehicle state quantity stabilization control and the wheel speed difference stabilization control are performed when a braking operation is performed by the driver of the vehicle. Since a load different from the time is applied and acceleration in the longitudinal direction of the vehicle, that is, G is generated, the behavior is easily changed. For this reason, by performing the vehicle state quantity stabilization control and the wheel speed difference stabilization control when the braking operation is performed, the behavior of the vehicle can be stabilized more effectively. As a result, the stability of the vehicle can be effectively ensured in a wider vehicle state region.

  The vehicle stabilization control device according to the present invention further includes a braking device that applies a braking force to the wheels in the above-described invention, and the vehicle state quantity stabilization control and the wheel speed difference stabilization control. Is performed by controlling a braking force applied to the wheel by the braking device.

  In the present invention, vehicle state quantity stabilization control and wheel speed difference stabilization control are performed by controlling the braking force applied to the wheels by the braking device. For this reason, it is not necessary to provide a new device for performing vehicle state quantity stabilization control and wheel speed difference stabilization control, and these stabilization controls can be easily performed. As a result, the stability of the vehicle can be ensured more easily in a wide vehicle state region.

  In the vehicle stabilization control device according to the present invention as set forth in the invention described above, the braking device includes a plurality of braking force distribution control means capable of controlling the distribution of the braking force applied to the wheels, and the driver of the vehicle. Braking force assisting means that can apply to the wheel a braking force that is greater than or equal to the braking force by the braking operation of the wheel speed difference stabilization control means, the wheel speed difference stabilization control means during the wheel speed difference stabilization control The method for controlling the distribution of the braking force by the braking force distribution adjusting means is switched according to the operating state of the braking force assisting means.

  In this invention, since the braking force distribution control method by the braking force distribution adjusting means is switched according to the operating state of the braking force assisting means at the time of wheel speed difference stabilization control, more optimal wheel speed difference stabilization control is performed. Can do. In other words, the braking of the wheels by the braking device differs in the braking force distribution control means that can be used when controlling the distribution of the braking force depending on the operating state of the braking force assisting means. Therefore, during the wheel speed difference stabilization control, the braking force distribution control method is switched by the braking force distribution adjusting unit according to the operating state of the braking force auxiliary unit, and the braking force distribution according to the operating state of the braking force auxiliary unit is switched. By distributing the braking force by the adjusting means, it is possible to more reliably distribute the braking force and to perform more optimal wheel speed difference stabilization control. As a result, the stability of the vehicle can be ensured more reliably in a wide vehicle state region.

  In the vehicle stabilization control device according to the present invention, in the above invention, the braking device controls the distribution of the braking force applied to the wheels during the wheel speed difference stabilization control. Control is performed from the distribution of the braking force applied to the rear wheels.

  In this invention, when controlling the distribution of the braking force applied to the wheel during the wheel speed difference stabilization control, the control is performed from the distribution of the braking force applied to the rear wheel, but it is applied to the wheel while the vehicle is running. When controlling the braking force to be applied, the braking force applied to the front wheels has a greater influence on the behavior of the vehicle than the braking force applied to the rear wheels. For this reason, at the time of wheel speed difference stabilization control, by controlling from the distribution of the braking force applied to the rear wheel, the distribution of the braking force can be controlled from the wheel having a small influence on the behavior of the vehicle. The influence on the controllability of the vehicle by performing the differential stabilization control can be minimized. As a result, the stability of the vehicle can be ensured in a wide vehicle state region while ensuring the controllability of the vehicle.

  In the vehicle stabilization control device according to the present invention as set forth in the invention described above, the actual wheel speed difference acquisition unit acquires the actual wheel speed difference of the front wheel and the actual wheel speed difference of the rear wheel, respectively, of the wheels. When controlling the distribution of the braking force applied to the wheel during the wheel speed difference stabilization control, the braking device controls the distribution of the braking force applied to the front wheel. The control is performed based on the actual wheel speed difference of the front wheel, and the distribution of the braking force applied to the rear wheel is controlled based on the actual wheel speed difference of the rear wheel.

  In this invention, when the wheel speed difference stabilization control is performed, the control of the distribution of the braking force applied to the front wheels is performed based on the actual wheel speed difference of the front wheels, and the control of the distribution of the braking force applied to the rear wheels is performed after the rear wheel. Since it is based on the difference between the actual wheel speeds of the wheels, more appropriate distribution of braking force can be performed. In other words, when the braking force applied to the wheels is controlled to perform wheel speed difference stabilization control, the actual wheel speed difference changes, so the front wheel actual wheel speed difference and the rear wheel actual wheel speed difference are different. May come. For this reason, more appropriate braking force distribution can be performed by controlling the distribution of the braking force based on the actual wheel speed difference between the wheels to be controlled for distributing the braking force. As a result, the stability of the vehicle can be ensured more reliably in a wide vehicle state region.

  In addition, the vehicle stabilization control device according to the present invention further includes a steering assist device that generates a steering assist force when the driver of the vehicle steers the wheel in the above-described invention, and the vehicle state The quantity stabilization control and the wheel speed difference stabilization control are performed by controlling the steering assist force generated by the steering assist device.

  In the present invention, vehicle state quantity stabilization control and wheel speed difference stabilization control are performed by controlling the steering assist force generated by the steering assist device. For this reason, it is not necessary to provide a new device for performing vehicle state quantity stabilization control and wheel speed difference stabilization control, and these stabilization controls can be easily performed. As a result, the stability of the vehicle can be ensured more easily in a wide vehicle state region.

  Further, in the vehicle stabilization control device according to the present invention, in the above invention, the wheel is a steering wheel that can be steered by the driver among the front wheels and the rear wheels, and the actual wheel speed difference The acquisition means is provided so as to be able to acquire the actual wheel speed difference of the front wheel and the actual wheel speed difference of the rear wheel of the wheels, and the steering assist device includes the wheel speed difference stabilization control. The steering assist force is sometimes generated based on the actual wheel speed difference of the front wheels.

  In the present invention, during the wheel speed difference stabilization control, the steering assist force is generated based on the actual wheel speed difference of the front wheels that are the steered wheels, so that a more appropriate steering assist force can be generated. That is, when the wheel speed difference stabilization control is performed, the actual wheel speed difference changes, so the actual wheel speed difference of the front wheels and the actual wheel speed difference of the rear wheels may differ. For this reason, when the steering assist force is generated by the steering assist device in order to perform the wheel speed difference stabilization control, the steering assist force is more appropriately generated by generating based on the actual wheel speed difference of the front wheels that are the steered wheels. Can be generated. As a result, the stability of the vehicle can be ensured more reliably in a wide vehicle state region.

  The vehicle stabilization control device according to the present invention has an effect that the stability of the vehicle can be ensured in a wider vehicle state region.

  Embodiments of a vehicle stabilization control device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  FIG. 1 is a schematic diagram of a vehicle provided with a vehicle stabilization control apparatus according to an embodiment of the present invention. The vehicle 1 including the vehicle stabilization control device 2 according to the embodiment uses the engine 10 which is an internal combustion engine as power generation means, and the power generated by the engine 10 is transmitted through the automatic transmission 15 to the wheels 5 of the vehicle 1. The vehicle can travel by being transmitted to a rear wheel 7 provided as a drive wheel. In this embodiment, the engine 10 is a reciprocating spark ignition engine that uses gasoline as fuel, but the engine 10 is not limited to this. The engine 10 may be, for example, a spark ignition engine that uses LPG (Liquefied Petroleum Gas) or alcohol as fuel, a so-called rotary spark ignition engine, or a diesel engine. It may be. The engine 10 has its engine speed and torque (output) controlled by an ECU (Electronic Control Unit) 90 that controls each part of the vehicle 1.

  The engine 10 as power generation means is mounted on the front portion in the traveling direction of the vehicle 1 and drives the rear wheel 7 via the automatic transmission 15, the propeller shaft 16, the differential gear 17, and the drive shaft 18. The rear wheel 7 is driven by a left rear wheel 7L, which is a rear wheel 7 positioned on the left side in the traveling direction of the vehicle 1, and a right rear wheel 7R, which is a rear wheel 7 positioned on the right side in the traveling direction of the vehicle 1. It is connected to the shaft 18 and both are provided as drive wheels. In addition, the vehicle 1 including the vehicle stabilization control device 2 according to the embodiment has a so-called FR (Front engine Rear) in which the engine 10 is mounted on a front portion in the traveling direction of the vehicle 1 and the rear wheel 7 is provided as a drive wheel. drive). Note that the vehicle stabilization control device 2 according to the embodiment can be applied to any vehicle 1 as long as the power of the power generation means is transmitted to the drive wheels. Further, the transmission for shifting the rotation of the engine 10 may be other than the automatic transmission 15, for example, a manual transmission for shifting manually.

  Of the wheels 5 of the vehicle 1, the rear wheels 7 are provided as drive wheels in this way, whereas the front wheels 6 are provided as steering wheels of the vehicle 1. The front wheel 6 that is a steered wheel is provided so as to be steerable by a handle 20 disposed in the driver's seat of the vehicle 1. The handle 20 is connected to an EPS (Electric Power Steering) device 31 that is a steering assist device that generates a steering assist force when the driver of the vehicle steers the wheel 5. Thus, since the handle 20 is connected to the EPS device 31, the front wheel 6 can be steered by operating the handle 20.

  Specifically, the handle 20 is connected to one end of a steering shaft 32 that is a rotating shaft when the steering wheel is operated during turning of the vehicle 1, and the other end of the steering shaft 32 is connected to the EPS device 31. Yes. The front wheel 6 includes a left front wheel 6L that is a front wheel 6 positioned on the left side in the traveling direction of the vehicle 1 and a right front wheel 6R that is a front wheel 6 positioned on the right side in the traveling direction of the vehicle 1. And is connected to a knuckle arm 36 positioned inward in the width direction of the vehicle 1 of each front wheel 6. The knuckle arm 36 and the EPS device 31 are connected by a tie rod 35. That is, the knuckle arm 36 and EPS device 31 connected to the left front wheel 6L, and the knuckle arm 36 and EPS device 31 connected to the right front wheel 6R are both connected by the tie rod 35 positioned between them. In addition, the EPS device 31 is provided with a steering angle sensor 86 that is a steering angle detection means for detecting a steering angle that is a rotation angle of the handle 20.

  Further, the vehicle 1 is provided with a braking device 40 that applies a braking force to the wheels 5. In the vicinity of each wheel 5, there is a wheel cylinder 71 that the braking device 40 has and that is operated by hydraulic pressure, and this wheel cylinder. A brake disc 75 is provided which is provided in combination with 71 and rotates integrally with the wheel 5 when the wheel 5 rotates. That is, the wheel cylinder 71 includes a left front wheel 6L, a right front wheel 6R, a left rear wheel 7L, and a wheel cylinder 71 provided in the vicinity of the right rear wheel 7R in order, a left front wheel wheel cylinder 72L, a right front wheel wheel cylinder 72R, and a left rear wheel. A wheel cylinder 73L and a right rear wheel wheel cylinder 73R are provided. Similarly, the brake disc 75 includes a left front wheel 6L, a right front wheel 6R, a left rear wheel 7L, and a brake disc 75 provided in the vicinity of the right rear wheel 7R. A wheel brake disc 77L and a right rear wheel brake disc 77R are provided.

  Among these, the wheel cylinder 71 is connected to a hydraulic pressure path 50 that is a hydraulic pressure path that acts on the wheel cylinder 71 when the vehicle 1 is braked. The hydraulic path 50 is provided with a brake actuator 60 capable of controlling the hydraulic pressure in the hydraulic path 50 when the vehicle 1 is braked. The brake actuator 60 independently controls the hydraulic pressure applied to each wheel cylinder 71. Can act. Thereby, the braking force of the plurality of wheels 5 can be generated independently.

  Further, near each wheel 5, a wheel speed sensor 85 that is a wheel speed detecting unit that detects a wheel speed that is a rotation speed of the wheel 5 is provided. The wheel speed sensor 85 is provided independently for each wheel 5 and can detect the wheel speed of each wheel 5 independently.

  The vehicle 1 also brakes an accelerator pedal 21 that is operated when adjusting the output of the engine 10 in the vicinity of the driver's feet when the driver is seated in the driver's seat of the vehicle 1 and the vehicle 1 that is running. A brake pedal 22 that is operated when performing the operation is also provided. Among these, an accelerator opening sensor 81 which is an accelerator opening detecting means capable of detecting the opening of the accelerator pedal 21 is provided in the vicinity of the accelerator pedal 21. The brake pedal 22 is connected to the hydraulic path 50 via a master cylinder 41 (see FIG. 2), which will be described later, and a brake capable of detecting the stroke of the brake pedal 22 in the vicinity of the brake pedal 22. A brake stroke sensor 82, which is a stroke detection means, is provided.

  The vehicle 1 is also provided with a G sensor 84 that can detect at least the acceleration in the width direction of the vehicle 1 and a yaw rate sensor 83 that is a yaw rate detection means that can detect the yaw rate when the vehicle 1 is traveling. . These accelerator opening sensor 81, brake stroke sensor 82, yaw rate sensor 83, G sensor 84, wheel speed sensor 85, rudder angle sensor 86, EPS device 31, brake actuator 60, engine 10 and automatic transmission 15 The ECU 90 is connected to the ECU 90 for controlling each of the components, and can be controlled by the ECU 90.

  FIG. 2 is a schematic diagram of the configuration of the braking device shown in FIG. A brake pedal 22 that is operated during braking of the vehicle 1 (see FIG. 1) is connected to an intake passage (not shown) of the engine 10 (see FIG. 1), thereby transmitting negative pressure generated during operation of the engine 10. Is connected to a brake booster 42 to which a negative pressure path 43 capable of performing the above is connected. In this way, the negative pressure path 43 connected to the brake booster 42 includes a negative pressure path check valve 44 that is a check valve that blocks air flow from the intake passage side toward the brake booster 42, and a negative pressure. A negative pressure sensor 45 which is a negative pressure detecting means capable of detecting the negative pressure in the path 43 is provided.

  The brake booster 42 is connected to a master cylinder 41 that can generate hydraulic pressure, and the hydraulic path 50 is connected to the master cylinder 41. As described above, the hydraulic path 50 connected to the master cylinder 41 is filled with brake fluid (not shown) used as hydraulic oil. The hydraulic path 50 is divided into two systems, and the first hydraulic path 51 and the second hydraulic path 52, which are the two hydraulic paths 50, are independently connected to the master cylinder 41. ing.

  The brake pedal 22 is connected to the hydraulic path 50 through the brake booster 42 and the master cylinder 41 as described above, and the brake booster 42 is a known vacuum booster, and the brake pedal The pedal force input to 22 is increased by utilizing the difference between the negative pressure transmitted from the negative pressure path 43 and the atmospheric pressure, and can be transmitted to the master cylinder 41. Further, the master cylinder 41 is provided so as to generate a hydraulic pressure by the force transmitted from the brake booster 42 and transmit the generated hydraulic pressure to the hydraulic path 50.

  Further, a wheel cylinder 71 is connected to the end of the hydraulic path 50 connected to the master cylinder 41, and the first hydraulic path 51 and the second hydraulic path 52 are arranged at alternate positions in the vehicle 1. A wheel cylinder 71 provided in the vicinity of the provided wheel 5 is connected. That is, the first front wheel wheel cylinder 72L and the right rear wheel wheel cylinder 73R are connected to the first hydraulic path 51, and the right front wheel wheel cylinder 72R and the left rear wheel wheel cylinder 73L are connected to the second hydraulic path 52. Yes.

  The hydraulic path 50 is provided with a plurality of solenoid valves that are brake actuators 60, a master cut solenoid valve 61 that is a normally open solenoid valve, a holding solenoid valve 62, and a decompression that is a normally closed solenoid valve. A solenoid valve 63 is provided. The master cut solenoid valve 61, the holding solenoid valve 62, and the pressure reducing solenoid valve 63 are provided as braking force distribution control means capable of controlling the distribution of the braking force applied to the wheels 5. Of these, one master cut solenoid valve 61 is provided in each of the first hydraulic path 51 and the second hydraulic path 52.

  The holding solenoid valve 62 is provided in a path from the master cylinder 41 to the wheel cylinder 71 through the master cut solenoid valve 61 in the hydraulic path 50, and the holding solenoid valves 62 correspond to the four wheel cylinders 71. Four are provided.

  Further, the pressure reducing solenoid valve 63 branches from a path from the holding solenoid valve 62 toward the wheel cylinder 71 and is provided in a return path 55 that is a path connected to a path between the master cut solenoid valve 61 and the holding solenoid valve 62. It has been. As described above, the return path 55 in which the pressure reducing solenoid valve 63 is provided is branched from the path between the four holding solenoid valves 62 and the wheel cylinder 71, and the pressure reducing solenoid valve 63 is provided in each branched path. Therefore, four pressure reducing solenoid valves 63 are provided in the hydraulic path 50. That is, four decompression solenoid valves 63 are provided corresponding to the four wheel cylinders 71 in the same manner as the holding solenoid valve 62.

  The return path 55 has a downstream side of the decompression solenoid valve 63, that is, a part of the return path 55 that is connected to a path between the master cut solenoid valve 61 and the holding solenoid valve 62 rather than the decompression solenoid valve 63. The two return paths 55 in the first hydraulic path 51 and the two return paths 55 in the second hydraulic path 52 are connected to each other to form one path. As described above, the pressurization pump 64 that is the brake actuator 60 and the return path check valve 65 that is a check valve provided in the return path 55 are disposed in a part of the return path 55 that forms one path. The return path check valve 65 is disposed on the return path 55 on the side connected to the path between the master cut solenoid valve 61 and the holding solenoid valve 62 rather than the pressurizing pump 64.

  Among these, a driving motor 66 is connected to the pressurizing pump 64, and the pressurizing pump 64 is operated by the driving motor 66, so that the brake fluid in the return path 55 is mastered from the pressure reducing solenoid valve 63 side. It is provided so as to be supplied to the cut solenoid valve 61 or the holding solenoid valve 62 side. The return path check valve 65 allows only the brake fluid from the pressurizing pump 64 toward the master cut solenoid valve 61 or the holding solenoid valve 62 to flow, and blocks the flow of the brake fluid in the opposite direction. Since the pressurizing pump 64 and the return path check valve 65 are provided as described above, one is provided in each of the first hydraulic path 51 and the second hydraulic path 52, and each of them is 2 in total. It is provided one by one.

  A supply path that is a path connected to the return path 55 from the upstream side of the master cut solenoid valve 61 in the hydraulic path 50, that is, from the portion between the master cylinder 41 and the master cut solenoid valve 61 in the hydraulic path 50. 56 is branched, and the supply path 56 is connected to the return path 55. The supply path 56 is provided with a reservoir 67 and a supply path check valve 68 that is a check valve provided in the supply path 56. The supply path check valve 68 is provided in the supply path 56. The reservoir 67 is disposed on the side connected to the path between the master cylinder 41 and the master cut solenoid valve 61.

  Among these, the reservoir 67 is provided so as to be able to store a predetermined amount of brake fluid flowing through the supply path 56, and the supply path check valve 68 is directed from the master cut solenoid valve 61 or the holding solenoid valve 62 toward the return path 55. Only flow the brake fluid to the, and block the flow of brake fluid in the opposite direction. Since the reservoir 67 and the supply path check valve 68 are provided as described above, one reservoir is provided in each of the first hydraulic path 51 and the second hydraulic path 52, and two each in total. Is provided.

  In addition, a master cylinder pressure sensor 69 serving as an operation pressure detection unit is provided between the master cylinder 41 and the master cut solenoid valve 61 in the first hydraulic path 51. The master cylinder pressure sensor 69 is an operation pressure generated when the driver depresses the brake pedal 22 by operating the brake between the master cylinder 41 and the master cut solenoid valve 61 in the first hydraulic path 51. Is provided so as to be detectable.

  The negative pressure sensor 45, the master cylinder pressure sensor 69, the master cut solenoid valve 61, the holding solenoid valve 62, the pressure reducing solenoid valve 63, and the drive motor 66 provided as described above are connected to the ECU 90 and can be controlled by the ECU 90. Is provided.

  FIG. 3 is a main part configuration diagram of the vehicle stabilization control device shown in FIG. 1. The ECU 90 is provided with a processing unit 91, a storage unit 120, and an input / output unit 121, which are connected to each other and can exchange signals with each other. Further, the engine 10, the automatic transmission 15, the EPS device 31, the accelerator opening sensor 81, the brake stroke sensor 82, the yaw rate sensor 83, the G sensor 84, the wheel speed sensor 85, the steering angle sensor 86, the negative connected to the ECU 90. The pressure sensor 45, the master cylinder pressure sensor 69, the master cut solenoid valve 61, the holding solenoid valve 62, the pressure reducing solenoid valve 63, and the drive motor 66 are connected to the input / output unit 121. Input and output signals to and from sensors.

  Further, the storage unit 120 stores a computer program for controlling the vehicle stabilization control device 2 according to the present embodiment. The storage unit 120 is a hard disk device, a magneto-optical disk device, a non-volatile memory such as a flash memory (a storage medium that can be read only such as a CD-ROM), or a RAM (Random Access Memory). A volatile memory or a combination thereof can be used.

  The processing unit 91 includes a memory and a CPU (Central Processing Unit), and an accelerator opening acquisition unit 92 that is an accelerator operation acquisition unit that can acquire the accelerator opening from the detection result of the accelerator opening sensor 81. The brake stroke amount acquisition unit 93 which is a braking operation acquisition means capable of acquiring the stroke amount of the brake pedal 22 from the detection result of the brake stroke sensor 82, and the rotation angle of the handle 20 from the detection result of the rudder angle sensor 86. A steering angle acquisition unit 94 that is a steering angle acquisition unit that can acquire a certain steering angle, a wheel speed acquisition unit 95 that is a wheel speed acquisition unit that can acquire a wheel speed from the detection result of the wheel speed sensor 85, and a yaw rate sensor From the detection result at 83, the actual vehicle capable of acquiring the yaw rate used as the actual vehicle state quantity that is the actual vehicle state quantity of the vehicle 1 A yaw rate acquisition unit 96 that is an attitude acquisition means, and a G acquisition unit 97 that is an actual vehicle state quantity acquisition means capable of acquiring a lateral G used as an actual vehicle state quantity from the detection result of the G sensor 84. ing.

  Further, the processing unit 91 controls the operating state of the wheel cylinder 71 by controlling the engine control unit 98 which is an engine control unit capable of controlling the operating state of the engine 10 and the braking device 40. A braking device control unit 99, an EPS device control unit 100 that is a steering assist device control unit capable of controlling the EPS device 31, and a braking determination unit that is a braking determination unit that determines whether or not the vehicle 1 is braking. Part 101.

  The processing unit 91 also includes a target vehicle state quantity deriving unit 102 that is a target vehicle state quantity deriving unit that derives a target vehicle state quantity that is a target vehicle state quantity, and the actual vehicle state quantity and the target vehicle state quantity are When the vehicle state quantity determination unit 103, which is a vehicle state quantity determination means for determining whether or not there is a divergence, and the actual vehicle state quantity and the target vehicle state quantity deviate, the vehicle 1 is controlled by performing motion control. A vehicle state quantity stabilization control unit 104 that is a vehicle state quantity stabilization control unit that performs vehicle state quantity stabilization control, which is control for bringing the vehicle state quantity close to the target vehicle state quantity.

  In addition, the processing unit 91 includes a target wheel speed difference deriving unit 105 that is a target wheel speed difference deriving unit that derives a target wheel speed difference that is a target wheel speed difference, and the actual left and right wheels 5 of the vehicle 1. An actual wheel speed difference acquisition unit 106 that is an actual wheel speed difference acquisition unit that acquires an actual wheel speed difference that is a wheel speed difference, and a wheel that determines whether or not the actual wheel speed difference is different from the target wheel speed difference. Whether the wheel speed difference determination unit 107 that is a speed difference determination means and the front wheel speed left / right difference that is the actual wheel speed difference of the front wheel 6 and the rear wheel speed left / right difference that is the actual wheel speed difference of the rear wheel 7 are in the same direction. If the actual wheel speed difference deviates from the target wheel speed difference, the actual wheel speed difference is determined by controlling the vehicle 1 when the actual wheel speed difference deviates from the target wheel speed difference. Wheel speed difference stabilization control, which is a control to bring the vehicle closer to the target wheel speed difference, and an actual vehicle When the attitude amount and the target vehicle state quantity deviate, the operation speed of the wheel speed difference stabilization control unit 109, which is a wheel speed difference stabilization control means for ending the wheel speed difference stabilization control, and the braking device 40 is changed. And a braking device operating state determining unit 110 which is a braking device operating state determining means for determining.

  The control of the EPS device 31 and the master cut solenoid valve 61 controlled by the ECU 90 is performed by, for example, a memory in which the processing unit 91 incorporates the computer program in the processing unit 91 based on a detection result by the wheel speed sensor 85 or the like. The control is performed by operating the operating parts such as the engine 10 and the EPS device 31 according to the result of the calculation. At that time, the processing unit 91 appropriately stores a numerical value in the middle of the calculation in the storage unit 120 and takes out the stored numerical value to execute the calculation. In addition, when controlling the engine 10 etc. in this way, you may control by the dedicated hardware different from ECU90 instead of the said computer program.

  The vehicle stabilization control device 2 according to this embodiment is configured as described above, and the operation thereof will be described below. When the vehicle 1 travels, the vehicle travels by operating the engine 10 and transmitting the power of the engine 10 to the rear wheels 7 as drive wheels. Specifically, during operation of the engine 10, the rotation of a crankshaft (not shown) of the engine 10 is transmitted to the automatic transmission 15, and the automatic transmission 15 is shifted at a gear ratio suitable for the traveling state of the vehicle 1. . The rotation shifted by the automatic transmission 15 is transmitted to the rear wheel 7 through the propeller shaft 16, the differential gear 17, and the drive shaft 18. Thereby, the rear wheel 7 which is a drive wheel rotates, and the vehicle 1 drive | works.

  Further, the vehicle speed of the vehicle 1 that travels by transmitting the rotation of the engine 10 to the rear wheel 7 is adjusted by operating the accelerator pedal 21 with a foot and adjusting the rotation speed and output of the engine 10. When the accelerator pedal 21 is operated, the stroke amount of the accelerator pedal 21, that is, the accelerator opening is detected by an accelerator opening sensor 81 provided in the vicinity of the accelerator pedal 21. The detection result by the accelerator opening sensor 81 is transmitted to the accelerator opening acquiring unit 92 included in the processing unit 91 of the ECU 90 and acquired by the accelerator opening acquiring unit 92. Further, the acquired accelerator opening is determined by the processing unit of the ECU 90. 91 is transmitted to the engine control unit 98 included in 91. The engine control unit 98 controls the engine 10 based on the accelerator opening obtained by the accelerator opening obtaining unit 92 and the detection results by other sensors.

  The vehicle 1 travels by operating the engine 10 in this way, and the wheel speed sensor 85 detects the wheel speed that is the rotational speed of the wheel 5 during traveling. The wheel speed detected by the wheel speed sensor 85 is transmitted to the wheel speed acquisition unit 95 included in the processing unit 91 of the ECU 90 and acquired by the wheel speed acquisition unit 95. When the wheel speed acquisition unit 95 acquires the wheel speed, the detection results by the four wheel speed sensors 85 are acquired independently. That is, the wheel speed acquisition unit 95 acquires the wheel speeds of the four wheels 5 independently.

  Further, when the vehicle speed is to be reduced at a speed lower than the speed reduction caused by returning the accelerator pedal 21 while the vehicle 1 is traveling, the brake is applied by depressing the brake pedal 22. As described above, when the brake is operated by stepping on the brake pedal 22, the pedaling force is transmitted to the brake booster 42. Here, a negative pressure path 43 is connected to the brake booster 42, and a negative pressure generated in the intake stroke during operation of the engine 10 is transmitted to the brake booster 42 through the negative pressure path 43. ing. Therefore, when a pedaling force is input to the brake booster 42, the brake booster 42 increases the pedaling force and inputs it to the master cylinder 41 by the differential pressure between the negative pressure and the atmospheric pressure. The master cylinder 41 to which the force increased with respect to the pedaling force is input applies pressure to the brake fluid in accordance with the input force, and increases the master cylinder hydraulic pressure.

  When the master cylinder hydraulic pressure increases, the brake fluid pressure in the hydraulic path 50 also increases, and the hydraulic pressure in the hydraulic path 50 becomes the same pressure as the master cylinder hydraulic pressure. Further, when the hydraulic pressure in the hydraulic path 50 rises in this way, this hydraulic pressure is also transmitted to the wheel cylinder 71 via the master cut solenoid valve 61 and the holding solenoid valve 62 which are normally open solenoid valves. In this case, since the pressure reducing solenoid valve 63 is normally closed, the brake fluid in the hydraulic path 50 does not flow from the holding solenoid valve 62 side through the pressure reducing solenoid valve 63 to the return path 55. The hydraulic pressure transmitted to the cylinder 71 does not decrease.

  As described above, when the increased hydraulic pressure is transmitted to the wheel cylinder 71, the wheel cylinder 71 is operated by the transmitted hydraulic pressure. That is, the wheel cylinder 71 operates with the master cylinder hydraulic pressure. When the wheel cylinder 71 is actuated, the wheel cylinder 71 is provided in combination with the wheel cylinder 71 and reduces the rotation speed of the brake disc 75 that rotates together with the wheel 5 when the wheel 5 rotates. . Thereby, since the rotational speed of the wheel 5 also falls, the vehicle 1 decelerates.

  By operating the brake pedal 22 as described above, the wheel cylinder 71 generates a braking force, which is a force that reduces the rotational speed of the brake disc 75. 5 can be reduced, and the vehicle 1 traveling can be braked.

  When operating the brake pedal 22 in this way, the stroke amount of the brake pedal 22 is detected by a brake stroke sensor 82 provided in the vicinity of the brake pedal 22. The detection result by the brake stroke sensor 82 is acquired by a brake stroke amount acquisition unit 93 included in the processing unit 91 of the ECU 90. The braking device control unit 99 included in the processing unit 91 of the ECU 90 controls the brake actuator 60 according to the stroke amount of the brake pedal 22 acquired by the brake stroke amount acquisition unit 93 and the detection results of other sensors provided in the vehicle 1. By doing so, the hydraulic pressure applied to the wheel cylinder 71 is controlled.

  When the pressure pump 64 is operated by operating the drive motor 66, the brake fluid in the return path 55 is moved in the direction of the path between the master cut solenoid valve 61 and the holding solenoid valve 62. Shed. Thereby, the hydraulic pressure of the brake fluid flowing in the direction of the holding solenoid valve 62 can be increased, and the hydraulic pressure applied to the wheel cylinder 71 can be increased. For this reason, it is possible to cause the wheel cylinder 71 to act on a hydraulic pressure higher than the hydraulic pressure generated when the driver steps on the brake pedal 22, and to increase the braking force. In other words, when the vehicle cylinder 1 is braked, when a hydraulic pressure higher than the hydraulic pressure generated when the driver depresses the brake pedal 22 is applied to the wheel cylinder 71, the drive motor 66 is operated and the pressurizing pump 64 is turned on. Operate. Thus, the pressurizing pump 64 is provided as a braking force assisting means that can apply to the wheels 5 a braking force that is equal to or greater than the braking force generated by the braking operation of the driver of the vehicle 1.

  Further, when changing the traveling direction of the vehicle 1 such as turning the vehicle 1, the steering wheel is operated. That is, the handle 20 is rotated about the steering shaft 32 as a rotation axis. When the steering shaft 32 is rotated by rotating the handle 20, the rotation is transmitted to the EPS device 31. The EPS device 31 to which the rotation of the steering shaft 32 is input outputs to the tie rod 35 in accordance with the rotation transmitted from the steering shaft 32 and a control signal from the EPS device control unit 100 included in the processing unit 91 of the ECU 90. . That is, when the rotation is transmitted from the steering shaft 32, the EPS device 31 applies a pressing force or a pulling force to the tie rod 35 according to the transmitted rotation and the control signal from the EPS device control unit 100.

  The force applied from the EPS device 31 to the tie rod 35 is transmitted to the knuckle arm 36, and the knuckle arm 36 rotates according to the direction and magnitude of the force applied from the EPS device 31 via the tie rod 35. Since the knuckle arm 36 is connected to the front wheel 6, when the knuckle arm 36 rotates, the front wheel 6 also rotates together with this rotation. As a result, the rotational direction of the front wheel 6 is different from the front-rear direction of the vehicle 1, so that the traveling direction of the vehicle 1 changes and the vehicle 1 turns.

  As described above, the vehicle 1 turns by operating the steering wheel 20, but the steering angle that changes by operating the steering wheel 20 is detected by the steering angle sensor 86 provided in the EPS device 31. The steering angle detected by the steering angle sensor 86 is transmitted to the steering angle acquisition unit 94 included in the processing unit 91 of the ECU 90 and acquired by the steering angle acquisition unit 94.

  When the vehicle 1 turns, a yaw moment that is a rotational force around the vertical axis of the vehicle 1 is generated in the vehicle 1. Thus, when a yaw moment is generated in the vehicle 1, the yaw rate sensor 83 detects a yaw rate that is a yaw angular velocity when the yaw moment is generated and the vehicle 1 rotates around the vertical axis. The yaw rate detected by the yaw rate sensor 83 is transmitted to the yaw rate acquisition unit 96 included in the processing unit 91 of the ECU 90 and acquired by the yaw rate acquisition unit 96.

  In addition, when the vehicle 1 turns, a centrifugal force is generated in the vehicle 1, and therefore, a lateral G, which is an acceleration in the width direction of the vehicle 1, that is, a lateral acceleration, is generated by the centrifugal force. Thus, the lateral G generated during the turning of the vehicle 1 is detected by the G sensor 84, and the detection result is acquired by the G acquisition unit 97 included in the processing unit 91 of the ECU 90.

  When the vehicle 1 travels, the vehicle 1 travels while acquiring the yaw rate and the lateral G as described above. These yaw rate and lateral G are used as actual vehicle state quantities that are actual vehicle state quantities of the vehicle 1. Further, when the vehicle 1 is traveling, a target vehicle state quantity that is a target vehicle state quantity is determined based on the steering angle acquired by the steering angle acquisition unit 94, the brake stroke amount acquired by the brake stroke amount acquisition unit 93, and the like. Derived by the target vehicle state quantity deriving unit 102 included in the processing unit 91 of the ECU 90. That is, the target vehicle state quantity deriving unit 102 derives a target yaw rate or lateral G as the target vehicle state quantity.

  When the target yaw rate or lateral G derived by the target vehicle state quantity deriving unit 102 is significantly different from the yaw rate acquired by the yaw rate acquisition unit 96 or the lateral G acquired by the G acquisition unit 97, the processing of the ECU 90 The vehicle state quantity stabilization control unit 104 of the unit 91 brings the actual yaw rate and lateral G acquired by the yaw rate acquisition unit 96 and the G acquisition unit 97 closer to the target vehicle state quantity derived by the target vehicle state quantity derivation unit 102. Vehicle state quantity stabilization control, which is control to be performed, is performed. This vehicle state quantity stabilization control is performed by performing motion control of the vehicle 1. Specifically, the braking force applied to the wheels 5 by the braking device 40 or the steering assist force generated by the EPS device 31 is controlled. This is done by controlling the assist torque.

  For example, when the vehicle 1 is braked when traveling straight ahead, if the vehicle 1 turns to the left or right direction in the traveling direction or the direction of the vehicle 1 changes, the vehicle 1 is Causes yaw rate and lateral G. That is, when the vehicle travels straight, the steering angle is 0 °, so the steering angle acquired by the steering angle acquisition unit 94 is also 0 °. Thereby, it can be determined that the vehicle is traveling straight ahead. Thus, since the yaw rate and the lateral G are not generated when the vehicle travels straight, in this case, the yaw rate and the lateral G used as the target vehicle state quantity in the target vehicle state quantity deriving unit 102 are both 0. To derive. That is, the target vehicle state quantity deriving unit 102 derives the target vehicle state quantity based on the rudder angle acquired by the rudder angle acquisition unit 94, and derives that the yaw rate and lateral G used as the target vehicle state quantity are zero. .

  On the other hand, the yaw rate or lateral G acquired as the actual vehicle state quantity is acquired from the yaw rate or lateral G actually generated in the vehicle 1 by the yaw rate acquisition unit 96 or G acquisition unit 97 provided as the actual vehicle state quantity acquisition means. To do. The vehicle state quantity stabilization control unit 104 includes the target vehicle state quantity derived by the target vehicle state quantity deriving unit 102 and the actual vehicle state quantity obtained by the actual vehicle state quantity obtaining unit, that is, the yaw rate obtaining unit 96 and the G obtaining unit 97. When the yaw rate or the lateral G acquired in step S is deviated, vehicle state quantity stabilization control is performed.

  Since this vehicle state quantity stabilization control is performed so that the actual vehicle state quantity approaches the target vehicle state quantity, the yaw rate and the lateral G, which are actual vehicle state quantities, are other than zero when braking is performed during straight traveling. In such a case, control is performed so that these become zero. Specifically, the actual vehicle state quantity is brought close to the target vehicle state quantity by performing cooperative control of the braking force distribution control of the four wheels and the steering control and performing the motion control of the vehicle 1.

  For example, when braking is performed during straight traveling, if the vehicle 1 heads leftward, the braking force on the right side of the vehicle 1 is reduced to the left by reducing the braking force on the left front wheel 6L or the left rear wheel 7L. Make it relatively larger than the braking force. Further, the EPS device 31 is operated to apply an assist torque, which is a steering assist force in the clockwise direction, to the handle 20 via the steering shaft 32, thereby urging the driver to turn the handle 20 to the right. By urging the driver to turn the handle 20 to the right, when the driver rotates the handle 20 to the right, the rudder angle changes so that the vehicle 1 moves in the right direction. The traveling direction changes according to the steering angle. That is, the EPS device 31 applies an assist torque in the clockwise direction to the handlebar 20 to change the traveling direction of the vehicle 1 to the right side than before the control. As a result, a clockwise yaw moment is generated in the vehicle 1 so that the vehicle 1 goes straight.

  When the vehicle 1 goes straight in this way, the yaw rate and the lateral G generated in the vehicle 1 become small, so the actual vehicle state quantity approaches the target vehicle state quantity. When the actual vehicle state quantity becomes close to the target vehicle state quantity, the vehicle 1 is traveling in a stable state, and the behavior of the vehicle 1 becomes stable.

  As described above, when the target vehicle state quantity and the actual vehicle state quantity are different from each other, the behavior of the vehicle 1 is stabilized by performing the vehicle state quantity stabilization control, but the behavior of the vehicle 1 becomes unstable. In this case, there is a case where a difference occurs between the left and right wheel speeds before the target vehicle state quantity and the actual vehicle state quantity deviate. For this reason, when the vehicle 1 travels, the actual wheel speed difference that is the actual wheel speed difference between the left and right wheels 5 is acquired by the actual wheel speed difference acquisition unit 106 included in the processing unit 91 of the ECU 90.

  Further, in order to derive a target wheel speed difference that is a wheel speed difference compared with an actual wheel speed difference and is a target wheel speed difference, a rudder angle acquisition unit 94 is derived as in the case of deriving a target vehicle state quantity. The target wheel speed difference deriving unit 105 of the processing unit 91 of the ECU 90 derives the target wheel speed difference based on the rudder angle acquired in step B1, the brake stroke amount acquired by the brake stroke amount acquiring unit 93, and the like.

  When the target wheel speed difference derived by the target wheel speed difference deriving unit 105 is significantly different from the actual wheel speed difference acquired by the actual wheel speed difference acquiring unit 106, the wheel speed difference of the processing unit 91 of the ECU 90 is included. In the stabilization control unit 109, wheel speed difference stabilization control, which is control for causing the actual wheel speed difference acquired by the actual wheel speed difference acquisition unit 106 to approach the target wheel speed difference derived by the target wheel speed difference deriving unit 105, is performed. Do. The wheel speed difference stabilization control is performed by controlling the motion of the vehicle 1. Specifically, as in the vehicle state quantity stabilization control, the braking force applied to the wheels 5 by the braking device 40 is controlled. , By controlling the assist torque generated by the EPS device 31.

  For example, if the behavior of the vehicle 1 becomes unstable when braking is performed while the vehicle 1 is traveling straight ahead, before the vehicle 1 actually changes, the left and right A wheel speed difference occurs in the wheel 5. Whether or not the vehicle is traveling straight ahead can be determined by the rudder angle acquired by the rudder angle acquisition unit 94, but when it is determined that the vehicle is traveling straight ahead from the rudder angle acquired by the rudder angle acquisition unit 94, In this case, the target wheel speed difference deriving unit 105 derives that the target wheel speed difference is zero.

  On the other hand, the actual wheel speed difference acquired by the actual wheel speed difference acquisition unit 106 is a wheel speed difference actually generated on the left and right wheels 5 of the vehicle 1. Therefore, the actual wheel speed difference acquisition unit 106 that acquires the actual wheel speed difference calculates the wheel speed difference between the left and right wheels 5 from each wheel speed acquired by the wheel speed acquisition unit 95 included in the processing unit 91 of the ECU 90. The calculated wheel speed difference is acquired as the actual wheel speed difference. The wheel speed difference stabilization control unit 109 determines whether the target wheel speed difference derived by the target wheel speed difference deriving unit 105 and the actual wheel speed difference acquired by the actual wheel speed difference acquiring unit 106 are different from each other. Speed difference stabilization control is performed.

  This wheel speed difference stabilization control is performed so as to bring the actual wheel speed difference closer to the target wheel speed difference. Therefore, when braking is performed during straight traveling, if the actual wheel speed difference is other than 0, the actual wheel speed difference is controlled. Control the speed difference to be zero. Specifically, as in the vehicle state quantity stabilization control, the cooperative control of the four-wheel braking force distribution control and the steering control is performed, and the vehicle 1 motion control is performed, whereby the actual wheel speed difference is determined as the target wheel speed. Get close to the difference.

  For example, when braking is performed during straight traveling, if the wheel speed of the left front wheel 6L is slower than the wheel speed of the right front wheel 6R, the EPS device 31 is activated and the steering wheel 32 is By applying the assist torque in the rotation direction, the driver is urged to turn the handle 20 to the right. As a result, when the driver rotates the steering wheel 20 to the right, the steering angle changes so that the vehicle 1 is directed rightward.

  Further, when the wheel speed of the left front wheel 6L is slower than the wheel speed of the right front wheel 6R, the braking force of the left front wheel 6L and the left rear wheel 7L is reduced, or the braking force of the right front wheel 6R and the right rear wheel 7R is increased. By increasing the braking force, the braking force on the right side of the vehicle 1 is relatively increased compared to the braking force on the left side. As a result, a clockwise yaw moment is generated in the vehicle 1, and the wheel speed reduction speed of the left front wheel 6L is made slower than the wheel speed reduction speed of the right front wheel 6R during braking. As a result, the wheel speed of the left front wheel 6L and the wheel speed of the right front wheel 6R approach each other, so that the wheel speed difference between the left and right wheels 5 becomes small, and the actual wheel speed difference approaches the target wheel speed difference. When the actual wheel speed difference and the target wheel speed difference become close, the situation in which the vehicle state quantity becomes unstable is eliminated, and the behavior of the vehicle 1 becomes stable.

  When performing the wheel speed difference stabilization control as described above, first, the EPS device 31 is operated to transmit the assist torque to the driver, thereby changing the actual wheel speed difference to the target wheel speed difference. After urging the driver to operate the steering wheel to give the steering angle in the approaching direction, the braking force of the rear wheel 7 is controlled, and then the braking force of the front wheel 6 is controlled. That is, when controlling the distribution of the braking force applied to the wheel 5 during the wheel speed difference stabilization control, the braking device 40 controls the distribution of the braking force applied to the rear wheel 7 out of the wheel 5 to control the rear wheel. When the wheel speed difference cannot be stabilized only by controlling the distribution of the braking force applied to 7, the distribution of the braking force applied to the front wheels 6 is controlled.

  FIG. 4 is a flowchart illustrating a processing procedure of the vehicle stabilization control apparatus according to the embodiment. Next, a control method of the vehicle stabilization control device 2 according to the embodiment, that is, a processing procedure of the vehicle stabilization control device 2 will be described. The following processing is called and executed every predetermined period when each unit is controlled while the vehicle 1 is traveling. In the processing procedure of the vehicle stabilization control device 2 according to the embodiment, first, it is determined whether or not braking is being performed (step ST101). This determination is performed by the braking determination unit 101 included in the processing unit 91 of the ECU 90. Whether or not braking is being performed by the braking determination unit 101 is determined by whether or not a stop lamp (not shown) provided at the rear end of the vehicle 1 is in an ON state, that is, in a lit state. Judge by.

  That is, since the stop lamp is turned on and lit when the driver of the vehicle 1 depresses the brake pedal 22 by performing a braking operation, the brake determination unit 101 acquires the state of the stop lamp, and the stop lamp is turned on. In the case of this state, it is determined that the braking operation by the driver of the vehicle 1 is being performed and the vehicle 1 is being braked. When the stop lamp is OFF, it is determined that no braking operation is performed by the driver and the vehicle 1 is not braking. If it is determined by this determination that braking is not being performed, the processing procedure is exited.

  When the braking determination unit 101 determines whether or not braking is being performed, the brake stroke amount acquisition unit 93 included in the processing unit 91 of the ECU 90 is determined based on the detection result of the brake stroke sensor 82 for the stroke amount of the brake pedal 22. If the acquired brake stroke amount is 0, it may be determined that braking is not being performed, and if it is not 0, it may be determined that braking is being performed.

  Next, an actual vehicle state quantity is acquired (step ST102). As the actual vehicle state quantity, the yaw rate detected by the yaw rate sensor 83 and the lateral G detected by the G sensor 84 are used. Among these, the yaw rate detected by the yaw rate sensor 83 is acquired by the yaw rate acquisition unit 96 included in the processing unit 91 of the ECU 90, and the lateral G detected by the G sensor 84 is acquired by the G acquisition unit 97 included in the processing unit 91 of the ECU 90. As a result, the yaw rate and the lateral G, which are actual vehicle state quantities, are acquired.

  Next, a target vehicle state quantity is derived (step ST103). When deriving the target vehicle state quantity, the brake angle is obtained from the rudder angle obtained by the rudder angle obtaining unit 94 included in the processing unit 91 of the ECU 90 from the detection result obtained by the rudder angle sensor 86 or the detection result obtained by the brake stroke sensor 82. The target vehicle state quantity deriving unit 102 included in the processing unit 91 of the ECU 90 derives from the brake stroke amount acquired by the stroke amount acquiring unit 93, the vehicle speed used in other control when the vehicle 1 is controlled, and the like. The target vehicle state quantity deriving unit 102 derives a target vehicle state quantity that is a target vehicle state quantity when the vehicle 1 is traveling at these steering angles and the like based on the steering angle and the like. For example, the target vehicle state quantity deriving unit 102 derives the target yaw rate and the target lateral G as the target vehicle state quantity.

  Next, it is determined whether or not the actual vehicle state quantity deviates from the target vehicle state quantity (step ST104). This determination is performed by the vehicle state quantity determination unit 103 included in the processing unit 91 of the ECU 90. The vehicle state quantity determination unit 103 uses the yaw rate or lateral G acquired as the actual vehicle state quantity by the yaw rate acquisition unit 96 or G acquisition unit 97 as the target vehicle state quantity derived by the target vehicle state quantity derivation unit 102. It is determined whether or not there is a deviation. Specifically, a threshold value of a difference between the actual vehicle state quantity and the target vehicle state quantity is set in advance and stored in the storage unit 120 of the ECU 90, and the difference between the actual vehicle state quantity and the target vehicle state quantity is stored. When it is larger than the threshold value stored in the unit 120, it is determined that the actual vehicle state quantity is different from the target vehicle state quantity. That is, the threshold value for the difference between the actual vehicle state quantity yaw rate and the target vehicle state quantity yaw rate, and the difference threshold value between the actual vehicle state quantity lateral G and the target vehicle state quantity lateral G are set and stored. 120, and at least one of the difference between the yaw rate of the actual vehicle state quantity and the yaw rate of the target vehicle state quantity and the difference between the lateral G of the actual vehicle state quantity and the lateral G of the target vehicle state quantity is If the difference threshold value stored in the storage unit 120 is larger than the difference threshold, it is determined that the actual vehicle state quantity is different from the target vehicle state quantity.

  If it is determined by the determination in the vehicle state quantity determination unit 103 (step ST104) that the actual vehicle state quantity is different from the target vehicle state quantity, the wheel speed difference stabilization control is terminated, and the vehicle state quantity is ended. Stabilization control is executed (step ST105). Of the wheel speed difference stabilization control and the vehicle state quantity stabilization control, the wheel speed difference stabilization control is performed by the wheel speed difference stabilization control unit 109 included in the processing unit 91 of the ECU 90. Therefore, the wheel speed difference stabilization control is performed. Is also completed by the wheel speed difference stabilization control unit 109. That is, when the wheel speed difference stabilization control unit 109 performs the wheel speed difference stabilization control, the wheel speed difference stabilization control is terminated. Further, since the vehicle state quantity stabilization control is performed by the vehicle state quantity stabilization control unit 104 included in the processing unit 91 of the ECU 90, the vehicle state quantity stabilization control is executed by the vehicle state quantity stabilization control unit 104.

  When the vehicle state quantity stabilization control unit 104 executes the vehicle state quantity stabilization control, the yaw rate or lateral G acquired by the yaw rate acquisition unit 96 or the G acquisition unit 97 is derived from the yaw rate derived by the target vehicle state quantity deriving unit 102. The movement control of the vehicle 1 is performed so as to approach the side G. That is, the vehicle state quantity stabilization control unit 104 causes the actual yaw rate and lateral G acquired by the yaw rate acquisition unit 96 and G acquisition unit 97 to approach the yaw rate and lateral G derived by the target vehicle state quantity derivation unit 102. By controlling the braking device 40 by the braking device control unit 99, the braking force distribution control of the four wheels is performed, or by operating the EPS device 31 by the EPS device control unit 100, the actual yaw rate and the lateral G are changed to the target vehicle state quantity. The motion of the vehicle 1 is controlled by urging the driver to change the rudder angle in a direction approaching the vehicle. As described above, the vehicle state quantity stabilization control unit 104 performs vehicle control that brings the actual vehicle state quantity close to the target vehicle state quantity by performing coordinated control of the four-wheel braking force distribution control and the steering control. Perform quantity stabilization control. After the vehicle state quantity stabilization control unit 104 performs the vehicle state quantity stabilization control, the processing procedure is exited.

  On the other hand, if it is determined by the determination in the vehicle state quantity determination unit 103 (step ST104) that the actual vehicle state quantity is not deviated from the target vehicle state quantity, then the wheel speed is acquired ( Step ST106). This acquisition is acquired by the wheel speed acquisition unit 95 by detecting the wheel speed by the wheel speed sensor 85 and transmitting the detection result to the wheel speed acquisition unit 95 of the processing unit 91 of the ECU 90. When the wheel speed acquisition unit 95 acquires the wheel speed, the wheel speed sensor 85 detects the wheel speeds of the four wheels 5 independently, and the wheel speed acquisition unit 95 determines the wheel speeds of the four wheels 5 independently. Get.

  Next, an actual wheel speed difference is acquired (step ST107). When acquiring the actual wheel speed difference, first, the wheel speed acquired by the wheel speed acquiring unit 95 is transmitted to the actual wheel speed difference acquiring unit 106 included in the processing unit 91 of the ECU 90. The actual wheel speed difference acquisition unit 106 determines the wheel speed difference between the left front wheel 6L and the right front wheel 6R and the wheel speed difference between the left rear wheel 7L and the right rear wheel 7R based on the wheel speed transmitted from the wheel speed acquisition unit 95. Is calculated. The wheel speed acquisition unit 95 acquires the wheel speed difference thus calculated as an actual wheel speed difference that is an actual wheel speed difference between the left and right wheels 5.

  Next, a target wheel speed difference is derived (step ST108). When this target wheel speed difference is derived, the steering angle acquired by the steering angle acquisition unit 94 and the brake stroke amount acquisition unit 93 are derived in the same manner as when the target vehicle state amount derivation unit 102 derives the target vehicle state amount. This is derived by the target wheel speed difference deriving unit 105 included in the processing unit 91 of the ECU 90 based on the brake stroke amount acquired in step 1 and the vehicle speed used in other control when the vehicle 1 is controlled. The target wheel speed difference deriving unit 105 derives a target wheel speed difference, which is a target wheel speed difference when the vehicle 1 is traveling at these steering angles, based on the steering angle.

  Next, it is determined whether or not the actual wheel speed difference is different from the target wheel speed difference (step ST109). This determination is performed by the wheel speed difference determination unit 107 included in the processing unit 91 of the ECU 90. The wheel speed difference determination unit 107 determines whether or not the actual wheel speed difference calculated and acquired by the actual wheel speed difference acquisition unit 106 is different from the target wheel speed difference derived by the target wheel speed difference deriving unit 105. To do.

  When this determination is made, the vehicle state amount determination unit 103 determines whether the actual vehicle state amount and the target vehicle state amount are different from each other. Is set in advance and stored in the storage unit 120 of the ECU 90. If the actual wheel speed difference is larger than the threshold stored in the storage unit 120, the actual wheel speed difference and the target wheel speed difference are Is determined to be deviated. Further, when comparing the difference between the actual wheel speed difference and the target wheel speed difference with the threshold value, the wheel speed difference of the front wheel 6 and the wheel speed difference of the rear wheel 7 are compared independently.

Specifically, the front wheel speed left-right difference ΔV_Fr, which is the actual wheel speed difference of the front wheel 6 when determining whether or not the actual wheel speed difference of the front wheel 6 is different from the target wheel speed difference, is the right front wheel 6R. Can be obtained by the following equation (1), where VW_FR is the wheel speed and VW_FL is the wheel speed of the left front wheel 6L. Whether or not the actual wheel speed difference and the target wheel speed difference of the front wheel 6 are deviated is determined by the absolute value of the front wheel speed difference ΔV_Fr calculated by the expression (1) as shown in the following expression (2). The determination is made based on whether or not the value is not less than Slip_Fr, which is the threshold value of the actual wheel speed difference of the front wheels 6.
ΔV_Fr = (VW_FR) − (VW_FL) (1)
| ΔV_Fr | ≧ Slip_Fr (2)

Similarly, when determining whether or not the difference between the actual wheel speed difference and the target wheel speed difference of the rear wheel 7 is different, the wheel speed of the right rear wheel 7R is set to VW_RR, and the wheel speed of the left rear wheel 7L is set to The rear wheel speed left-right difference ΔV_Rr, which is the actual wheel speed difference of the rear wheel 7 in the case of VW_RL, is obtained by the following equation (3). Further, whether the difference between the actual wheel speed difference and the target wheel speed difference of the rear wheel 7 is determined is determined by the difference between the left and right rear wheel speeds calculated by the equation (3) as shown in the following equation (4). The determination is made based on whether or not the absolute value of ΔV_Rr is equal to or greater than Slip_Rr, which is the threshold value of the actual wheel speed difference of the rear wheel 7.
ΔV_Rr = (VW_RR) − (VW_RL) (3)
| ΔV_Rr | ≧ Slip_Rr (4)

  When it is determined by the wheel speed difference determination unit 107 that the actual wheel speed difference and the target wheel speed difference are not deviated, that is, | ΔV_Fr | ≧ Slip_Fr and | ΔV_Rr | ≧ Slip_Rr. If at least one of the above is not established, the processing procedure is exited.

On the other hand, when it is determined by the wheel speed difference determination unit 107 that the actual wheel speed difference is different from the target wheel speed difference, that is, | ΔV_Fr | ≧ Slip_Fr and | ΔV_Rr | If ≧ Slip_Rr holds, it is next determined whether or not the front wheel speed left / right difference and the rear wheel speed left / right difference are in the same direction (step ST110). This determination is performed by the wheel speed difference direction determination unit 108 included in the processing unit 91 of the ECU 90. The wheel speed difference direction determination unit 108 determines whether or not the front wheel speed left / right difference ΔV_Fr obtained by the equation (1) and the rear wheel speed left / right difference ΔV_Rr obtained by the equation (3) are in the same direction. This is performed based on equation (5).
(ΔV_Fr) × (ΔV_Rr)> 0 (5)

  In other words, when the front wheel speed left / right difference ΔV_Fr and the rear wheel speed left / right difference ΔV_Rr are in the same direction, the sign indicating the positive / negative value in the value obtained by multiplying both is +. Can be determined that the front wheel speed left-right difference and the rear wheel speed left-right difference are in the same direction. That is, when Expression (5) is established, the front wheel 6 and the rear wheel 7 determine that the wheel speed of the wheel 5 on the same side of the left and right wheels 5 is faster than the other wheel speed. be able to. If it is determined by this determination that the front wheel speed left / right difference and the rear wheel speed left / right difference are not in the same direction, the processing procedure is exited.

  If it is determined by the wheel speed difference direction determination unit 108 that the front wheel speed left / right difference and the rear wheel speed left / right difference are in the same direction, next, wheel speed difference stabilization control is executed (step ST111). ). The wheel speed difference stabilization control is performed by the wheel speed difference stabilization control unit 109 included in the processing unit 91 of the ECU 90. The wheel speed difference stabilization control unit 109 controls the motion of the vehicle 1 so that the actual wheel speed difference acquired by the actual wheel speed difference acquisition unit 106 approaches the target wheel speed difference derived by the target wheel speed difference deriving unit 105. Do.

  That is, the wheel speed difference stabilization control unit 109 is configured so that the actual wheel speed difference acquired by the actual wheel speed difference acquisition unit 106 approaches the target wheel speed difference derived by the target wheel speed difference deriving unit 105. By controlling the braking device 40 by 99, the braking force distribution control of the four wheels is performed, or by operating the EPS device 31 by the EPS device control unit 100, the steering angle in the direction in which the actual wheel speed difference approaches the target wheel speed difference. The motion of the vehicle 1 is controlled by prompting the driver to change the vehicle speed. As described above, the wheel speed difference stabilization control unit 109 performs the coordinated control of the braking force distribution control of the four wheels and the steering control, thereby making the wheel speed that is a control for bringing the actual wheel speed difference closer to the target wheel speed difference. Perform differential stabilization control. When the wheel speed difference stabilization control unit 109 executes the wheel speed difference stabilization control, the control flow of the wheel speed difference stabilization control is executed.

  FIG. 5 is a flowchart showing a processing procedure of wheel speed difference stabilization control. When performing wheel speed difference stabilization control, first, assist torque by the EPS device 31 is controlled (step ST201). In this control, the wheel speed difference stabilization control unit 109 included in the processing unit 91 of the ECU 90 transmits a control signal when performing wheel speed difference stabilization control to the EPS device control unit 100 included in the processing unit 91 of the ECU 90. This is performed by the EPS device control unit 100. The EPS device control unit 100 controls the EPS device 31 according to the front wheel speed left / right difference acquired by the actual wheel speed difference acquisition unit 106 and causes the EPS device 31 to generate assist torque. The assist torque is torque that rotates the steering shaft 32, that is, torque that is transmitted to the driver through the handle 20.

  The EPS device control unit 100 controls the EPS device 31 to generate assist torque, thereby prompting the driver through the handle 20 to correct the rudder suitable for bringing the actual wheel speed difference close to the target wheel speed difference. The driver operates the steering wheel 20 with the direction and magnitude of the assist torque transmitted through the steering wheel 20 so that the front wheel 6 is oriented at a steering angle suitable for bringing the actual wheel speed difference close to the target wheel speed difference. Change.

  FIG. 6 is an explanatory diagram showing the relationship between the front wheel speed left-right difference and the assist torque. The horizontal axis in the figure shows the front wheel speed left-right difference ΔV_Fr, the left side of the figure shows the state in which the wheel speed of the left front wheel 6L is higher than the wheel speed of the right front wheel 6R, and the right side This shows a state in which the wheel speed of the right front wheel 6R is higher than the wheel speed of the left front wheel 6L, and shows a state in which the absolute value of the front wheel speed left-right difference ΔV_Fr increases as the distance from the center increases. ing. In addition, the vertical axis in the figure indicates the assist torque T_A, the lower side in the figure indicates the magnitude of the assist torque T_A when the front wheel 6 is directed leftward, and the upper side in the figure indicates the front wheel 6. The magnitude of the assist torque T_A when the direction is rightward is shown, and the absolute value of the assist torque T_A increases as the distance from the center increases.

  The assist torque T_A generated by controlling the EPS device 31 by the EPS device control unit 100 is determined by the direction and magnitude of the front wheel speed difference ΔV_Fr. That is, as shown in FIG. 6, when the wheel speed of the left front wheel 6L is higher than the wheel speed of the right front wheel 6R, the assist torque T_A that causes the front wheel 6 to operate in the left direction is generated in the EPS device 31. The absolute value of the assist torque T_A is increased as the absolute value of the front wheel speed difference ΔV_Fr increases. Similarly, when the wheel speed of the right front wheel 6R is higher than the wheel speed of the left front wheel 6L, the EPS device 31 is caused to generate an assist torque T_A for operating the front wheel 6 in the right direction, and the front wheel speed left-right difference As the absolute value of ΔV_Fr increases, the absolute value of the assist torque T_A is increased.

  The assist torque T_A generated by controlling the EPS device 31 by the EPS device control unit 100 is determined based on the direction and magnitude of the front wheel speed left-right difference ΔV_Fr. That is, as shown in FIG. 6, when the wheel speed of the left front wheel 6L is higher than the wheel speed of the right front wheel 6R, the assist torque T_A that causes the front wheel 6 to operate in the left direction is generated in the EPS device 31. The absolute value of the assist torque T_A is increased as the absolute value of the front wheel speed difference ΔV_Fr increases. Accordingly, the driver is prompted by the assist torque transmitted through the handle 20 to adjust the steering angle by operating the handle 20 so that the direction of the front wheel 6 changes to the left direction. Change direction. Here, the state in which the wheel speed of the left front wheel 6L is higher than the wheel speed of the right front wheel 6R indicates a state in which the vehicle 1 is directed rightward. In this state, the front wheel 6 is turned to the left. When the direction is changed, the vehicle 1 approaches a straight traveling state. As a result, the absolute value of the front wheel speed difference ΔV_Fr becomes small.

  Further, when the wheel speed of the right front wheel 6R is higher than the wheel speed of the left front wheel 6L, the EPS device 31 is caused to generate an assist torque T_A for operating the front wheel 6 in the right direction, and the front wheel speed left-right difference Δ As the absolute value of V_Fr increases, the absolute value of assist torque T_A is increased. Accordingly, the driver is prompted by the assist torque transmitted through the handle 20 to adjust the steering angle by operating the handle 20 so that the direction of the front wheel 6 changes to the right. Change direction. Here, the state in which the wheel speed of the right front wheel 6R is higher than the wheel speed of the left front wheel 6L indicates a state in which the vehicle 1 is directed leftward. When the direction is changed, the vehicle 1 approaches a straight traveling state. As a result, the absolute value of the front wheel speed difference ΔV_Fr becomes small. The EPS device control unit 100 causes the EPS device 31 to generate the assist torque T_A so that the driver performs the operation of giving the steering angle in the direction in which the front wheel 6 with the higher wheel speed is located as described above. The absolute value of the front wheel speed difference ΔV_Fr is decreased.

  Further, the EPS device control unit 100 causes the EPS device 31 to generate the assist torque T_A as described above, but an upper limit value is set for the absolute value of the assist torque T_A. That is, as shown in FIG. 6, regardless of the direction of the front wheel speed left / right difference ΔV_Fr between the left and right front wheels 6, the absolute value of the front wheel speed left / right difference ΔV_Fr is greater than a predetermined value, that is, the left front wheel 6L and the right When a wheel speed difference greater than or equal to a predetermined value occurs between the front wheels 6R, the EPS device 31 generates a certain upper limit assist torque T_A.

  Further, the EPS device 31 does not generate the assist torque T_A when the absolute value of the front wheel speed left-right difference ΔV_Fr is less than the threshold for performing the steering cooperative control. That is, when the absolute value of the front wheel speed left-right difference ΔV_Fr is less than the Clip_Fr_st, which is a threshold for performing the steering cooperative control, the EPS device control unit 100 does not generate the assist torque T_A in the EPS device 31 and The assist torque T_A is generated in the EPS device 31 only when the absolute value of the speed left-right difference ΔV_Fr is equal to or greater than the Clip_Fr_st.

  Next, it is determined whether the pressurizing pump 64 is operating (step ST202). This determination is made by the braking device operating state determination unit 110 included in the processing unit 91 of the ECU 90. The brake actuator 60 of the brake device 40 is controlled by the brake device control unit 99 included in the processing unit 91 of the ECU 90, but the brake device operation state determination unit 110 detects a control signal from the brake device control unit 99 to the brake actuator 60. By doing so, it is detected whether or not the pressurizing pump 64 is operating. The braking device operating state determination unit 110 determines whether the pressurizing pump 64 is operating based on the detection result. If it is determined by this determination that the pressurizing pump 64 is not in operation, the process proceeds to step ST205 described later.

  If it is determined by the braking device operating state determination unit 110 (step ST202) that the pressurizing pump 64 is operating, next, it is determined whether or not the front wheel speed left-right difference is greater than or equal to a predetermined value. Determination is made (step ST203). This determination is performed by the wheel speed difference determination unit 107 included in the processing unit 91 of the ECU 90. The wheel speed difference determination unit 107 determines whether or not the absolute value of the front wheel speed left / right difference ΔV_Fr calculated by the actual wheel speed difference acquisition unit 106 performs braking force control using the pressure pump 64. It is determined whether or not the value is not less than a predetermined value of Slip_Fr_p.

  Note that this Slip_Fr_p is a value equal to or greater than Slip_Fr, which is the threshold value of the actual wheel speed difference of the front wheel 6 used when determining whether or not the actual wheel speed difference of the front wheel 6 is deviated from the target wheel speed difference. And stored in the storage unit 120 of the ECU 90 in advance. That is, Slip_Fr_p and Slip_Fr are stored in advance in the storage unit 120 in a relationship of Slip_Fr_p> Slip_Fr. If it is determined by the wheel speed difference determination unit 107 that the absolute value of the front wheel speed left / right difference ΔV_Fr is not equal to or greater than the predetermined value Slip_Fr_p, the process proceeds to step ST205 described later.

  If the absolute value of the front wheel speed difference ΔV_Fr is determined to be greater than or equal to the predetermined value Slip_Fr_p by the determination by the wheel speed difference determination unit 107 (step ST203), the pressure pump 64 and the master cut solenoid valve 61 The left / right braking force is controlled (step ST204). In this control, the wheel speed difference stabilization control unit 109 included in the processing unit 91 of the ECU 90 transmits a control signal when performing the wheel speed difference stabilization control to the braking device control unit 99 included in the processing unit 91 of the ECU 90. Is performed by the braking device control unit 99. Here, when the wheel speed difference stabilization control unit 109 performs the wheel speed difference stabilization control via the braking device control unit 99, the wheel speed difference stabilization control unit 109 sets the operation state of the pressurizing pump 64. Accordingly, the braking force distribution control method by the master cut solenoid valve 61, the holding solenoid valve 62, and the pressure reducing solenoid valve 63, which are braking force distribution adjusting means, is switched. Therefore, if it is determined by the braking device operating state determination unit 110 (step ST202) that the pressurization pump 64 is operating, the wheel speed difference stabilization control unit 109 determines that the master cut solenoid valve 61 Then, a control signal is transmitted to the braking device control unit 99 so as to control the distribution of the braking force of the wheels 5.

  FIG. 7 is an explanatory diagram showing the relationship between the front wheel speed left / right difference and the required braking force difference. When the braking device control unit 99 controls the distribution of the braking force applied to the left and right wheels 5, the control is performed based on the front wheel speed left / right difference ΔV_Fr calculated by the actual wheel speed difference acquisition unit 106. For example, as shown in FIG. 7, a map of a required braking force difference that is a difference in braking force applied to the left and right front wheels 6 with respect to the front wheel speed left / right difference ΔV_Fr is created in advance and stored in the storage unit 120 of the ECU 90. When the braking device control unit 99 controls the distribution of the braking force applied to the left and right front wheels 6, the map compares the front wheel speed left / right difference ΔV_Fr calculated by the actual wheel speed difference acquisition unit 106. . Thereby, the required braking force difference is derived, and the distribution of the braking force applied to the left and right front wheels 6 is controlled so as to be the derived required braking force difference. When this control is performed, first, the pressurization amount is controlled by controlling the pressurization pump 64 and the master cut solenoid valve 61 through the control of the drive motor 66.

  FIG. 8 is an explanatory diagram showing the relationship between the front wheel speed left-right difference and the pressurization amount. The horizontal axis in the figure shows the front wheel speed left-right difference ΔV_Fr as in FIG. Further, the vertical axis in FIG. 8 indicates the amount of pressure ΔP when the hydraulic pressure in the hydraulic path 50 is increased by the pressure pump 64, and the lower side of the figure indicates the hydraulic pressure that acts on the left front wheel wheel cylinder 72L. A pressurization amount ΔP in the case of pressurizing with respect to the hydraulic pressure of the first hydraulic path 51 as a path is shown, and the upper side of the figure shows the second hydraulic path 52 that is a path of hydraulic pressure applied to the right front wheel wheel cylinder 72R. The pressure amount ΔP in the case of pressurizing with respect to the hydraulic pressure is shown, and the pressure amount ΔP increases as the distance from the center increases.

  The pressurization amount ΔP that is changed by controlling the pressurization pump 64 through the control of the drive motor 66 by the braking device control unit 99 is determined by the direction and magnitude of the front wheel speed left-right difference ΔV_Fr. That is, as shown in FIG. 8, when the wheel speed of the left front wheel 6L is higher than the wheel speed of the right front wheel 6R, the pressurization amount ΔP for the hydraulic pressure in the first hydraulic path 51 is increased. That is, by actuating the pressurizing pump 64 provided in the first hydraulic path 51, the hydraulic pressure in the first hydraulic path 51, which is the hydraulic path that is applied to the left front wheel wheel cylinder 72L, is increased. Further, the pressure amount ΔP at that time is increased as the absolute value of the front wheel speed difference ΔV_Fr increases. Thereby, the hydraulic pressure applied to the left front wheel wheel cylinder 72L can be increased, and the braking force of the left front wheel 6L can be increased. Here, the state in which the wheel speed of the left front wheel 6L is higher than the wheel speed of the right front wheel 6R indicates a state in which the vehicle 1 is directed rightward. In this state, the braking force of the left front wheel 6L Is increased, the vehicle 1 approaches a straight traveling state. As a result, the absolute value of the front wheel speed difference ΔV_Fr becomes small.

  Similarly, when the wheel speed of the right front wheel 6R is higher than the wheel speed of the left front wheel 6L, the pressurization amount ΔP for the hydraulic pressure in the second hydraulic path 52 is increased. That is, by actuating the pressurizing pump 64 provided in the second hydraulic path 52, the hydraulic pressure in the second hydraulic path 52, which is the hydraulic path to be applied to the right front wheel wheel cylinder 72R, is increased. Further, the pressure amount ΔP at that time is increased as the absolute value of the front wheel speed difference ΔV_Fr increases. Thereby, the hydraulic pressure applied to the right front wheel wheel cylinder 72R can be increased, and the braking force of the right front wheel 6R can be increased. Here, the state in which the wheel speed of the right front wheel 6R is higher than the wheel speed of the left front wheel 6L indicates a state in which the vehicle 1 is directed rightward. In this state, the braking force of the right front wheel 6R Is increased, the vehicle 1 approaches a straight traveling state. As a result, the absolute value of the front wheel speed difference ΔV_Fr becomes small.

  When the pressure amount ΔP in the pressure pump 64 is increased to increase the braking force of the left front wheel 6L or the right front wheel 6R as described above, the operation amount of the pressure pump 64 and the master cut solenoid valve 61 are increased. By controlling the opening degree, the hydraulic pressure applied to the left front wheel wheel cylinder 72L and the right front wheel wheel cylinder 72R is adjusted, and the braking force is controlled. That is, since the master cut solenoid valve 61 is a normally open solenoid valve, even when the pressure pump 64 is operated, the brake fluid pressurized by the pressure pump 64 normally passes through the master cut solenoid valve 61. However, when the opening degree of the master cut solenoid valve 61 is reduced, the amount of brake fluid passing through the master cut solenoid valve 61 decreases and flows in the direction of the wheel cylinder 71. Increases the amount of brake fluid. In this case, since the hydraulic pressure acting on the wheel cylinder 71 is increased, the braking force is increased.

  When the braking force of the left front wheel 6L and the right front wheel 6R is controlled by increasing the amount of pressure ΔP applied by the pressure pump 64, the first hydraulic path 51 and the second hydraulic path 52 are respectively set in this way. By controlling the pressurizing pump 64 and the master cut solenoid valve 61 provided, the hydraulic pressure applied to the left front wheel wheel cylinder 72L and the right front wheel wheel cylinder 72R is adjusted, and the braking force of the left and right front wheels 6 is controlled. The braking device control unit 99 controls the pressurizing pump 64 and the master cut solenoid valve 61 that can increase the hydraulic pressure acting on the wheel cylinder 71 on the front wheel 6 side with the higher wheel speed as described above. Thus, the braking force of the front wheel 6 with the higher wheel speed is increased, and the absolute value of the front wheel speed left-right difference ΔV_Fr is decreased.

  Further, the braking device control unit 99 changes the pressurization amount ΔP by controlling the pressurization pump 64 in this way, and an upper limit value is set for the pressurization amount ΔP. That is, as shown in FIG. 8, regardless of the direction of the front wheel speed left / right difference ΔV_Fr between the left and right front wheels 6, the absolute value of the front wheel speed left / right difference ΔV_Fr is greater than a predetermined value, that is, the left front wheel 6L and the right When a wheel speed difference of a predetermined value or more occurs between the front wheels 6R, the braking device control unit 99 keeps the pressure amount ΔP by the pressure pump 64 constant.

  When the absolute value of the front wheel speed left-right difference ΔV_Fr is less than the predetermined value Slip_Fr_p for controlling the pressurization by the pressurization pump 64, the braking device control unit 99 does not perform the pressurization control and does not perform the pressurization pump. The pressure amount ΔP by 64 is not increased. That is, when the absolute value of the front wheel speed left / right difference ΔV_Fr is less than the predetermined value Slip_Fr_p for controlling the pressurization by the pressurization pump 64, the braking device control unit 99 applies the pressurization amount ΔP by the pressurization pump 64. The pressure increase amount ΔP is increased by the pressure pump 64 only when the absolute value of the front wheel speed left-right difference ΔV_Fr is not less than Slip_Fr_p. As described above, when the braking force of the left and right front wheels 6 is controlled by controlling the pressurizing pump 64 and the master cut solenoid valve 61, the processing procedure of the wheel speed difference stabilization control is exited.

  When it is determined that the pressurization pump 64 is not in operation by the determination in the braking device operating state determination unit 110 (step ST202), or the front wheel speed is determined by the determination in the wheel speed difference determination unit 107 (step ST203). If it is determined that the absolute value of the left / right difference ΔV_Fr is not greater than or equal to the predetermined value Slip_Fr_p, then the rear wheel speed left / right difference is greater than or equal to the predetermined value and the braking force applied to each wheel 5 by electronic control is applied. It is determined whether or not EBD (Electronic Brake Force Distribution) to be distributed is in progress (step ST205).

  Among these, the wheel speed difference determination unit 107 included in the processing unit 91 of the ECU 90 determines whether or not the difference between the left and right rear wheel speeds is equal to or greater than a predetermined value. The wheel speed difference determination unit 107 uses the holding solenoid valve 62 and the pressure reducing solenoid valve 63 to control the braking force of the rear wheel 7 based on the absolute value of the rear wheel speed difference ΔV_Rr calculated by the actual wheel speed difference acquisition unit 106. It is determined whether or not it is equal to or greater than a predetermined value of Slip_Rr_s when determining whether or not to perform. Note that this Slip_Rr_s is not less than Slip_Rr, which is a threshold value of the actual wheel speed difference of the rear wheel 7 used when determining whether or not the actual wheel speed difference of the rear wheel 7 is deviated from the target wheel speed difference. And stored in the storage unit 120 of the ECU 90 in advance. That is, Slip_Rr_s and Slip_Rr are stored in the storage unit 120 in advance in a relationship of Slip_Rr_s> Slip_Rr.

  In addition, it is determined whether or not the EBD is being performed, that is, the braking device 40 controls the braking force applied to each wheel 5 to a braking force suitable for each wheel 5 according to the driving state of the vehicle 1. It is determined by the braking device operating state determination unit 110 that the processing unit 91 of the ECU 90 has. When the brake device operating state determination unit 110 determines whether or not the brake device 40 is in EBD, it is the same as in the case of determining whether or not the pressure pump 64 is in operation (step ST202). In addition, the control signal from the braking device control unit 99 to the brake actuator 60 is detected by the braking device operating state determination unit 110 to detect whether or not the EBD is being performed. Based on the detection result, the braking device operating state determination unit 110 determines whether the braking device 40 is in EBD.

  When it is determined by the wheel speed difference determination unit 107 that the absolute value of the rear wheel speed left-right difference ΔV_Rr is not greater than or equal to the predetermined value Slip_Rr_s, or by the determination by the braking device operating state determination unit 110, the braking device 40 is If it is determined that the EBD is not being performed, the process exits the wheel speed difference stabilization control process.

  When the determination by the wheel speed difference determination unit 107 and the braking device operating state determination unit 110 (step ST205) determines that the absolute value of the rear wheel speed left-right difference ΔV_Rr is equal to or greater than the predetermined value Slip_Rr_s and is in EBD For this, the left and right braking force of the rear wheel 7 is controlled by the holding solenoid valve 62 and the pressure reducing solenoid valve 63 (step ST206). In this control, the wheel speed difference stabilization control unit 109 included in the processing unit 91 of the ECU 90 transmits a control signal when performing the wheel speed difference stabilization control to the braking device control unit 99 included in the processing unit 91 of the ECU 90. Is performed by the braking device control unit 99. If it is determined by the braking device operating state determination unit 110 (step ST202) that the pressurization pump 64 is not operating, the wheel speed difference stabilization control unit 109 includes the holding solenoid valve 62 and the pressure reducing valve. A control signal is transmitted to the braking device control unit 99 so that the solenoid valve 63 controls the distribution of the braking force of the wheels 5. Thus, the braking device control unit 99 controls the holding solenoid valve 62 and the pressure reducing solenoid valve 63 to control the distribution of the braking force of the wheels 5.

  FIG. 9 is an explanatory diagram showing the relationship between the difference between the left and right rear wheel speeds and the required braking force difference. When the braking device control unit 99 controls the distribution of the braking force applied to the left and right rear wheels 7, the control is performed based on the rear wheel speed left / right difference ΔV_Rr calculated by the actual wheel speed difference acquisition unit 106. For example, as shown in FIG. 9, a map of a required braking force difference that is a difference in braking force applied to the left and right rear wheels 7 with respect to the rear wheel speed left / right difference ΔV_Rr is created in advance and stored in the storage unit 120 of the ECU 90. When the braking device control unit 99 controls the distribution of the braking force applied to the left and right rear wheels 7, the rear wheel speed right / left difference Δ calculated by the actual wheel speed difference acquisition unit 106 is added to this map. Check V_Rr. Thus, the distribution of the braking force applied to the left and right rear wheels 7 is controlled by deriving the required braking force difference and controlling the holding solenoid valve 62 and the pressure reducing solenoid valve 63 so as to be the derived required braking force difference. To do.

  When the braking device control unit 99 controls the holding solenoid valve 62 and the pressure reducing solenoid valve 63 to control the braking force of the rear wheel 7, the wheel speed of the left rear wheel 7L is equal to the wheel speed of the right rear wheel 7R. If the speed is faster, the braking force of the left rear wheel 7L is increased, or the braking force of the right rear wheel 7R is reduced, thereby increasing the braking force of the left rear wheel 7L. Increase compared to. On the other hand, when the wheel speed of the right rear wheel 7R is higher than the wheel speed of the left rear wheel 7L, the braking force of the right rear wheel 7R is increased or the braking force of the left rear wheel 7L is decreased. As a result, the braking force of the right rear wheel 7R is increased as compared with the braking force of the left rear wheel 7L.

  For example, when the wheel speed of the left rear wheel 7L is higher than the wheel speed of the right rear wheel 7R, the pressure reduction corresponding to the right rear wheel wheel cylinder 73R among the four pressure reduction solenoid valves 63 included in the braking device 40. Open the solenoid valve 63. As a result, the brake fluid in the return path 55 branched from the path from the holding solenoid valve 62 toward the right rear wheel wheel cylinder 73R can pass through the pressure reducing solenoid valve 63. When the hydraulic pressure is increased, part of the brake fluid that flows through the path between the holding solenoid valve 62 and the right rear wheel wheel cylinder 73R flows into the return path 55. For this reason, the hydraulic pressure acting on the right rear wheel wheel cylinder 73R is reduced, and the braking force of the right rear wheel 7R is reduced.

  When the wheel speed of the left rear wheel 7L is higher than the wheel speed of the right rear wheel 7R, the holding solenoid valve 62 corresponding to the right front wheel wheel cylinder 72R is increased in order to increase the braking force of the left rear wheel 7L. Close. As a result, the brake fluid in the second hydraulic path 52 does not flow from the master cut solenoid valve 61 side to the right front wheel wheel cylinder 72R even when the hydraulic pressure in the second hydraulic path 52 is increased. , And flows toward the holding solenoid valve 62 corresponding to the left rear wheel wheel cylinder 73L. For this reason, the amount of brake fluid flowing through the holding solenoid valve 62 corresponding to the left rear wheel wheel cylinder 73L and flowing to the left rear wheel wheel cylinder 73L increases, and the hydraulic pressure acting on the left rear wheel wheel cylinder 73L increases. The braking force of the left rear wheel 7L increases.

  When the wheel speed of the left rear wheel 7L is higher than the wheel speed of the right rear wheel 7R, the braking device control unit 99 controls the holding solenoid valve 62 and the pressure reducing solenoid valve 63 in this way. When the wheel speed of the right rear wheel 7R is higher than the wheel speed of the left rear wheel 7L, control opposite to the above-described control is performed. That is, by opening the pressure reducing solenoid valve 63 corresponding to the left rear wheel wheel cylinder 73L, the hydraulic pressure acting on the left rear wheel wheel cylinder 73L is reduced, and the braking force of the left rear wheel 7L is reduced. Further, by closing the holding solenoid valve 62 corresponding to the left front wheel wheel cylinder 72L, the hydraulic pressure acting on the right rear wheel wheel cylinder 73R is increased, and the braking force of the right rear wheel 7R is increased.

  The braking device control unit 99 controls the holding solenoid valve 62 and the pressure-reducing solenoid valve 63 as described above, so that the wheel cylinder 71 that brakes the rear wheel 7 positioned on the side where the wheel speed is fast in the wheel 5 to the left and right. By increasing the acting hydraulic pressure, the braking force of the rear wheel 7 is increased, and by reducing the hydraulic pressure acting on the wheel cylinder 71 that brakes the rear wheel 7 located on the side where the wheel speed is slow, this pressure is reduced. The braking force of the rear wheel 7 is reduced. As a result, the absolute value of the rear wheel speed difference ΔV_Rr is reduced.

  Next, it is determined whether the front wheel speed left-right difference is equal to or greater than a predetermined value (step ST207). This determination is performed by the wheel speed difference determination unit 107 included in the processing unit 91 of the ECU 90. The wheel speed difference determination unit 107 determines whether the absolute value of the front wheel speed left / right difference ΔV_Fr calculated by the actual wheel speed difference acquisition unit 106 controls the braking force of the front wheel 6 using the holding solenoid valve 62 and the pressure reducing solenoid valve 63. It is determined whether or not it is equal to or greater than a predetermined value of Slip_Fr_s when determining whether or not.

  Note that this Slip_Fr_s is equal to or greater than Slip_Fr, which is a threshold value of the actual wheel speed difference of the front wheel 6 used when determining whether or not the actual wheel speed difference of the front wheel 6 is deviated from the target wheel speed difference. Prestored in the storage unit 120 of the ECU 90. That is, Slip_Fr_s and Slip_Fr are stored in the storage unit 120 in advance in a relationship of Slip_Fr_s> Slip_Fr. Further, this Slip_Fr_s is larger than a predetermined value Slip_Rr_s when it is determined whether or not the braking force control of the rear wheel 7 is performed using the holding solenoid valve 62 and the pressure reducing solenoid valve 63, and these are Slip_Fr_s>. The relationship is “Slip_Rr_s”. When it is determined by the wheel speed difference determination unit 107 that the absolute value of the front wheel speed left / right difference ΔV_Fr is not equal to or greater than the predetermined value Slip_Fr_s, the process exits the wheel speed difference stabilization control process.

  If it is determined by the wheel speed difference determination unit 107 (step ST207) that the absolute value of the front wheel speed left-right difference ΔV_Fr is greater than or equal to a predetermined value Slip_Fr_s, the holding wheel 6 and the pressure reducing solenoid valve 63 use the front wheel 6 The left and right braking force is controlled (step ST208). This control is performed by controlling the holding solenoid valve 62 and the pressure reducing solenoid valve 63 by the braking device control unit 99 included in the processing unit 91 of the ECU 90. When controlling the distribution of the braking force applied to the front wheels 6 by the braking device control unit 99, the control is performed based on the front wheel speed right / left difference ΔV_Fr calculated by the actual wheel speed difference acquisition unit 106. In this control, a front wheel speed left / right difference Δ calculated by the actual wheel speed difference acquisition unit 106 is displayed on a map (see FIG. 7) showing a relationship between the front wheel speed left / right difference and the required braking force difference stored in the storage unit 120 of the ECU 90 in advance. By comparing V_Fr, the required braking force difference is derived, and the distribution of the braking force applied to the left and right front wheels 6 is controlled so as to be the derived required braking force difference.

  When the braking device control unit 99 controls the holding solenoid valve 62 and the pressure reducing solenoid valve 63 to control the braking force of the front wheel 6, the wheel speed of the left front wheel 6L is compared with the wheel speed of the right front wheel 6R. If it is fast, the braking force of the right front wheel 6R is reduced. Conversely, when the wheel speed of the right front wheel 6R is higher than the wheel speed of the left front wheel 6L, the braking force of the left front wheel 6L is reduced.

  For example, when the wheel speed of the left front wheel 6L is higher than the wheel speed of the right front wheel 6R, the holding solenoid valve 62 corresponding to the right front wheel wheel cylinder 72R is closed in order to reduce the braking force of the right front wheel 6R. At the same time, the pressure reducing solenoid valve 63 corresponding to the right front wheel wheel cylinder 72R is opened. Thus, by closing the holding solenoid valve 62 corresponding to the right front wheel wheel cylinder 72R, the brake fluid in the second hydraulic path 52 causes the master cut solenoid even when the hydraulic pressure in the second hydraulic path 52 is increased. It does not flow from the valve 61 side to the right front wheel wheel cylinder 72R. Further, by opening the pressure reducing solenoid valve 63 corresponding to the right front wheel wheel cylinder 72R, the brake fluid in the second hydraulic path 52 between the holding solenoid valve 62 and the right front wheel wheel cylinder 72R passes through the pressure reducing solenoid valve 63. Therefore, the amount of brake fluid flowing to the right front wheel wheel cylinder 72R is reduced. For this reason, the hydraulic pressure acting on the right front wheel wheel cylinder 72R is reduced, and the braking force of the right front wheel 6R is reduced.

  On the contrary, when the wheel speed of the right front wheel 6R is higher than the wheel speed of the left front wheel 6L, the holding solenoid valve 62 corresponding to the left front wheel wheel cylinder 72L is set to reduce the braking force of the left front wheel 6L. Simultaneously with the closing, the pressure reducing solenoid valve 63 corresponding to the left front wheel cylinder 72L is opened. Thus, even if the brake fluid in the first hydraulic path 51 increases the hydraulic pressure in the first hydraulic path 51 by closing the holding solenoid valve 62 corresponding to the left front wheel wheel cylinder 72L, the master cut solenoid. It does not flow from the valve 61 side to the left front wheel wheel cylinder 72L. Further, by opening the pressure reducing solenoid valve 63 corresponding to the left front wheel wheel cylinder 72L, the brake fluid in the first hydraulic path 51 between the holding solenoid valve 62 and the left front wheel wheel cylinder 72L passes through the pressure reducing solenoid valve 63. Therefore, the amount of brake fluid flowing to the left front wheel wheel cylinder 72L is reduced. For this reason, the hydraulic pressure acting on the left front wheel wheel cylinder 72L is reduced, and the braking force of the left front wheel 6L is reduced. In this way, when the braking force of the left and right front wheels 6 is controlled by controlling the holding solenoid valve 62 and the pressure reducing solenoid valve 63, the processing procedure of the wheel speed difference stabilization control is exited. After exiting from the processing procedure of the wheel speed difference stabilization control, the process returns to the processing procedure of the vehicle stabilization control device 2 (see FIG. 4), and further exits from the processing procedure of the vehicle stabilization control device 2.

  In the vehicle stabilization control device 2 described above, the vehicle state quantity determination unit 103 compares the actual vehicle state quantity and the target vehicle state quantity, and when both deviate, the vehicle state quantity stabilization control unit 104 uses the vehicle state quantity. Quantity stabilization control is performed. Thereby, when the behavior of the vehicle 1 becomes unstable, the behavior can be stabilized. Further, the actual wheel speed difference acquiring unit 106 acquires the actual wheel speed difference, the target wheel speed difference deriving unit 105 derives the target wheel speed difference, and the wheel speed difference determining unit 107 determines that they are separated. In this case, the wheel speed difference stabilization control unit 109 performs wheel speed difference stabilization control, which is control for bringing the actual wheel speed difference closer to the target wheel speed difference. The vehicle state amount is an amount that represents the state of the vehicle 1 when the behavior of the vehicle 1 actually changes, but the wheel speed difference is not only when the behavior of the vehicle 1 changes, but also when there is an indication of a change. Also occurs. For this reason, when the vehicle 1 travels, an actual wheel speed difference that is an actual wheel speed difference between the left and right wheels 5 is acquired. If the acquired actual wheel speed difference deviates from the target wheel speed difference, the vehicle 1 It can be determined that this is a sign of unstable behavior. Therefore, in this case, the behavior of the vehicle 1 can be stabilized by performing wheel speed difference stabilization control, which is control for bringing the actual wheel speed difference closer to the target wheel speed difference.

  As described above, in the vehicle stabilization control device 2 according to the embodiment, when the actual vehicle state quantity deviates from the target vehicle state quantity, the vehicle state quantity stabilization control is performed, and the actual wheel speed difference and the target wheel speed are controlled. When the difference deviates, wheel speed difference stabilization control is performed. Thereby, when stabilizing the behavior of the vehicle 1, not only the vehicle state region in which the behavior of the vehicle 1 can be determined by the vehicle state amount, but also the vehicle state region before the change in the vehicle state amount appears, that is, the vehicle state The behavior of the vehicle 1 can be stabilized even in the vehicle state region where the change in behavior cannot be determined by the amount. In other words, in a vehicle state region in which a change in behavior cannot be determined by the vehicle state quantity, a small change in behavior of the vehicle 1 due to a wheel speed difference between the left and right wheels 5 of the vehicle 1 or a sign that the behavior becomes unstable is determined. Speed difference stabilization control is performed. As a result, the behavior of the vehicle 1 can be stabilized even in a vehicle state region in which a change in behavior cannot be determined by the vehicle state quantity. As a result, the stability of the vehicle 1 can be ensured in a wider vehicle state region.

  In addition, since the wheel speed difference stabilization control is performed in the vehicle state region where the behavior change cannot be determined by the vehicle state quantity, the control intervention is prevented from being delayed when the control for stabilizing the behavior of the vehicle 1 is performed. it can. In addition, in this manner, since the wheel speed difference stabilization control is performed in the vehicle state region in which the change in behavior cannot be determined by the vehicle state quantity, a small change in behavior has occurred so that the change in behavior cannot be determined by the vehicle state quantity. Even in this case, the behavior of the vehicle 1 can be stabilized by the wheel speed difference stabilization control. Thereby, it can suppress that the passenger | crew of the vehicle 1 feels uncomfortable by the change of the small behavior of the vehicle 1 continuing. As a result, it is possible to stabilize the vehicle 1 more quickly and to improve the comfort when the vehicle 1 is traveling.

  Further, since the vehicle state quantity stabilization control and the wheel speed difference stabilization control are performed when the braking operation by the driver of the vehicle 1 is performed, the behavior of the vehicle 1 is effectively stabilized. Can do. That is, when the vehicle 1 is braked, a load different from that at the time of constant speed operation is applied to the wheel 5 and acceleration in the front-rear direction of the vehicle 1, that is, G is generated, so that the behavior is easily changed. For this reason, when the braking operation is performed, the behavior of the vehicle 1 can be stabilized more effectively by performing the vehicle state quantity stabilization control and the wheel speed difference stabilization control. As a result, the stability of the vehicle 1 can be effectively ensured in a wider vehicle state region.

  Further, when performing the stabilization control of the behavior of the vehicle 1, the vehicle state quantity stabilization control and the wheel speed difference stabilization control are performed by controlling the braking force applied to the wheels 5 by the braking device 40. For this reason, it is not necessary to provide a new device for performing vehicle state quantity stabilization control and wheel speed difference stabilization control, and these stabilization controls can be easily performed. As a result, the stability of the vehicle 1 can be ensured more easily in a wide vehicle state region.

  Further, the wheel speed difference stabilization control unit 109 is controlled by the brake actuator 60 such as the master cut solenoid valve 61, the holding solenoid valve 62, and the pressure reducing solenoid valve 63 according to the operating state of the pressure pump 64 during the wheel speed difference stabilization control. Since the braking force distribution control method is switched, more optimal wheel speed difference stabilization control can be performed. In other words, the braking of the wheel 5 by the braking device 40 differs depending on the brake actuator 60 that can be used when controlling the distribution of the braking force depending on the operating state of the pressurizing pump 64. For this reason, at the time of wheel speed difference stabilization control, the control method of the distribution of the braking force by the brake actuator 60 is switched according to the operating state of the pressurizing pump 64, and the braking actuator 60 according to the operating state of the pressurizing pump 64 is controlled. By distributing the power, the braking force can be more reliably distributed, and more optimal wheel speed difference stabilization control can be performed. As a result, the stability of the vehicle 1 can be ensured more reliably in a wide vehicle state region.

  Further, during the operation of the pressurizing pump 64, the distribution of the braking force applied to the wheels 5 by the master cut solenoid valve 61 is controlled, so that more accurate control can be performed. That is, since the opening degree of the master cut solenoid valve 61 can be set to a desired opening degree as well as full opening and full closing, the hydraulic pressure applied to the wheel cylinder 71 can be controlled with high accuracy. Further, as described above, since the opening degree of the master cut solenoid valve 61 is not only fully opened and fully closed, it is possible to suppress sound during operation. As a result, the distribution of the braking force applied to the wheels 5 can be controlled with higher accuracy, and the quietness can be improved when controlling the distribution of the braking force.

  In addition, the distribution of the braking force applied to the wheels 5 is controlled by the pressurizing pump 64 and the master cut solenoid valve 61 only when the absolute value of the front wheel speed left-right difference ΔV_Fr is equal to or greater than the predetermined value Slip_Fr_p. The distribution of the braking force can be controlled. That is, when the absolute value of the front wheel speed right / left difference ΔV_Fr is small, the pressurization amount of the hydraulic pressure in the hydraulic path 50 adjusted by the pressurization pump 64 and the master cut solenoid valve 61 is also small. If is too small, it may be difficult to adjust the amount of pressurization. On the other hand, in the vehicle stabilization control device 2 according to the embodiment, the pressure pump 64 and the master cut solenoid valve 61 apply the wheel 5 only when the absolute value of the front wheel speed right / left difference ΔV_Fr is equal to or greater than the predetermined value Slip_Fr_p. Since the distribution of the braking force to be controlled is performed, the pressurization amount can be adjusted more accurately. As a result, the distribution of the braking force applied to the wheel 5 can be controlled more reliably with high accuracy.

  Further, when controlling the distribution of the braking force applied to the wheel 5 during the wheel speed difference stabilization control, the control is performed from the distribution of the braking force applied to the rear wheel 7. When the braking force applied to the vehicle is controlled, the braking force applied to the front wheel 6 has a greater influence on the behavior of the vehicle 1 than the braking force applied to the rear wheel 7. For this reason, at the time of wheel speed difference stabilization control, by controlling from the distribution of the braking force applied to the rear wheel 7, the distribution of the braking force can be controlled from the wheel 5 having a small influence on the behavior of the vehicle 1. The influence on the maneuverability of the vehicle 1 by performing the wheel speed difference stabilization control can be minimized. As a result, the stability of the vehicle 1 can be ensured in a wide vehicle state region while ensuring the controllability of the vehicle 1.

  Further, when performing the wheel speed difference stabilization control, the control of the distribution of the braking force applied to the front wheel 6 is performed based on the actual wheel speed difference of the front wheel 6, and the control of the distribution of the braking force applied to the rear wheel 7 is performed. Since it is based on the actual wheel speed difference of the rear wheel 7, more appropriate distribution of braking force can be performed. That is, when the braking force applied to the wheel 5 is controlled in order to perform the wheel speed difference stabilization control, the actual wheel speed difference changes, so the actual wheel speed difference of the front wheel 6 and the actual wheel speed difference of the rear wheel 7 are changed. May be different. For example, when the control of the braking force distribution of the rear wheel 7 is performed prior to the control of the braking force distribution of the front wheel 6 during the wheel speed difference stabilization control, only the actual wheel speed difference of the rear wheel 7 is detected. Therefore, the actual wheel speed difference of the front wheel 6 and the actual wheel speed difference of the rear wheel 7 are different. Therefore, in this case, when controlling the distribution of the braking force of the front wheels 6, the control is performed based on the actual wheel speed difference of the front wheels 6. That is, more appropriate braking force distribution can be performed by controlling the distribution of the braking force based on the actual wheel speed difference of the wheels 5 to be controlled to distribute the braking force. As a result, the stability of the vehicle 1 can be ensured more reliably in a wide vehicle state region.

  Further, when the stabilization control of the behavior of the vehicle 1 is performed, the vehicle state quantity stabilization control and the wheel speed difference stabilization control are performed by controlling the assist torque generated by the EPS device 31. For this reason, it is not necessary to provide a new device for performing vehicle state quantity stabilization control and wheel speed difference stabilization control, and these stabilization controls can be easily performed. As a result, the stability of the vehicle 1 can be ensured more easily in a wide vehicle state region.

  Further, during the wheel speed difference stabilization control, the assist torque is generated by the EPS device 31 based on the actual wheel speed difference of the front wheel 6 that is the steered wheel, so that more appropriate assist torque can be generated. That is, when the wheel speed difference stabilization control is performed, the actual wheel speed difference changes, so the actual wheel speed difference of the front wheel 6 and the actual wheel speed difference of the rear wheel 7 may differ. For this reason, when the assist torque is generated by the EPS device 31 in order to perform the wheel speed difference stabilization control, the assist torque can be generated more appropriately by being generated based on the actual wheel speed difference of the front wheels 6. . As a result, the stability of the vehicle 1 can be ensured more reliably in a wide vehicle state region.

  Further, during the wheel speed difference stabilization control, the assist torque generated by the EPS device 31 is controlled before the braking force applied to the wheel 5 by the braking device 40, so that the behavior can be stabilized more reliably. Can be achieved. That is, when the wheel speed difference stabilization control is performed by controlling the assist torque generated by the EPS device 31, the behavior is stabilized by changing the direction of the front wheel 6. A linear effect can be obtained. In addition, when the wheel speed difference stabilization control is performed by controlling the assist torque generated by the EPS device 31, the driver can make a correction by operating the steering wheel 20, so that the behavior is more reliably performed. Can be stabilized. As a result, the stability of the vehicle 1 can be ensured more reliably in a wide vehicle state region.

  FIG. 10 is a main part configuration diagram of a vehicle stabilization control device according to a modification. In the vehicle stabilization control device 2 described above, the actual wheel speed difference acquisition unit 106 provided in the processing unit 91 of the ECU 90 acquires the actual wheel speed difference, and the target wheel speed difference derivation unit 105 calculates the target wheel speed difference. When the actual wheel speed difference deviates from the target wheel speed difference, the wheel speed difference stabilization control unit 109 controls the vehicle 1 so that the actual wheel speed difference is brought close to the target wheel speed difference. Although certain wheel speed difference stabilization control is performed, the wheel speed difference stabilization control may be performed by other methods.

  For example, the wheel speed difference stabilization control may be controlled so that the vehicle state quantity approaches the target vehicle state quantity, similarly to the vehicle state quantity stabilization control. In this case, as shown in FIG. 10, as an example, an estimated vehicle state quantity estimating unit 130 that is an estimated vehicle state quantity estimating unit that estimates the estimated vehicle state quantity based on the actual wheel speed difference is provided in the processing unit 91 of the ECU 90. Provide. Further, the vehicle state quantity determination unit 103 determines whether or not the estimated vehicle state quantity estimated by the estimated vehicle state quantity estimation unit 130 deviates from the target vehicle state quantity derived by the target vehicle state quantity derivation unit 102. . The wheel speed difference stabilization control unit 109 performs wheel speed difference stabilization control when it is determined by the vehicle state quantity determination unit 103 that the estimated vehicle state quantity is deviated from the target vehicle state quantity. Thereby, the estimated vehicle state quantity estimated based on the actual wheel speed difference is brought close to the target vehicle state quantity.

  Thus, in the vehicle stabilization control device according to the modification, when determining whether or not to perform the wheel speed difference stabilization control, the estimated vehicle state quantity depends on whether or not the estimated vehicle state quantity is deviated from the target vehicle state quantity. When determining and determining whether or not to perform the vehicle state quantity stabilization control, is the actual vehicle state quantity deviated from the target vehicle state quantity as in the vehicle stabilization control device 2 according to the embodiment? Judgment is based on whether or not As described above, in any vehicle state region, the state of the vehicle 1 is determined based on the vehicle state quantity, so that it can be easily determined when determining the behavior of the vehicle 1. As a result, the stability of the vehicle 1 can be ensured more easily in a wide vehicle state region.

  Further, in the vehicle stabilization control device 2 according to the embodiment, when it is determined that the pressurization pump 64 is operating (step ST202), the master cut solenoid valve 61 controls the distribution of the braking force of the wheels 5. However, if it is determined that the pressurizing pump 64 is operating, the master cut solenoid valve 61, the holding solenoid valve 62, and the pressure reducing solenoid valve 63 may be used in combination. When controlling the distribution of the braking force of the wheel 5, the braking force of the wheel 5 can be more accurately distributed by using these together. As a result, the stability of the vehicle 1 can be ensured more reliably in a wide vehicle state region.

  Further, in the vehicle stabilization control device 2 according to the embodiment, the yaw rate and the lateral G are used as the actual vehicle state quantity, and the ECU 90 serves as an actual vehicle state quantity acquisition unit that acquires the yaw rate and the lateral G. Although the yaw rate acquisition unit 96 and the G acquisition unit 97 are provided, the actual vehicle state quantity may use a state quantity other than the yaw rate or the lateral G. As the actual vehicle state quantity acquisition unit, the yaw rate acquisition unit 96 or G Means other than the acquisition unit 97 may be used. The actual vehicle state quantity only needs to be a state quantity capable of recognizing the behavior of the vehicle 1 that is running, and the actual vehicle state quantity acquisition unit only needs to be able to acquire this state quantity.

  Moreover, although the vehicle stabilization control apparatus 2 which concerns on an Example is demonstrated as what is provided in the vehicle 1 which used the engine 10 which is an internal combustion engine as a motive power generation means, the vehicle stabilization control apparatus 2 is others It may be mounted on a vehicle of the form. The vehicle stabilization control device 2 is, for example, an EV (Electric Vehicle) vehicle that uses a motor that operates by electricity as power generation means, or a hybrid vehicle that is a vehicle that uses both an engine and a motor as power generation means. The power generation means of the vehicle may be of any type.

  As described above, the vehicle stabilization control device according to the present invention is useful for a vehicle in which the braking force can be adjusted independently by each wheel, and particularly suitable for improving the stability of the vehicle during braking. Yes.

1 is a schematic view of a vehicle provided with a vehicle stabilization control device according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram of the braking device shown in FIG. 1. It is a principal part block diagram of the vehicle stabilization control apparatus shown in FIG. It is a flowchart which shows the process sequence of the vehicle stabilization control apparatus which concerns on an Example. It is a flowchart which shows the process sequence of wheel speed difference stabilization control. It is explanatory drawing which shows the relationship between front-wheel speed right-and-left difference and assist torque. It is explanatory drawing which shows the relationship between a front-wheel speed left-right difference and a request | requirement braking force difference. It is explanatory drawing which shows the relationship between front-wheel speed right-and-left difference and the amount of pressurization. It is explanatory drawing which shows the relationship between a rear-wheel speed left-right difference and a request | requirement braking force difference. It is a principal part block diagram of the vehicle stabilization control apparatus which concerns on a modification.

Explanation of symbols

1 Vehicle 2 Vehicle Stabilization Control Device 5 Wheel 6 Front Wheel 7 Rear Wheel 10 Engine 20 Handle 22 Brake Pedal 31 EPS Device 40 Braking Device 41 Master Cylinder 42 Brake Booster 50 Hydraulic Path 51 First Hydraulic Path 52 Second Hydraulic Path 55 Return Path 56 Supply path 60 Brake actuator 61 Master cut solenoid valve 62 Holding solenoid valve 63 Pressure reducing solenoid valve 64 Pressure pump 65 Return path check valve 66 Driving motor 71 Wheel cylinder 75 Brake disc 82 Brake stroke sensor 83 Yaw rate sensor 84 G sensor 85 Wheel speed sensor 86 Rudder angle sensor 90 ECU
91 Processing Unit 92 Accelerator Opening Acquisition Unit 93 Brake Stroke Acquisition Unit 94 Steering Angle Acquisition Unit 95 Wheel Speed Acquisition Unit 96 Yaw Rate Acquisition Unit 97 G Acquisition Unit 98 Engine Control Unit 99 Braking Device Control Unit 100 EPS Device Control Unit 101 Braking Determination Unit 102 target vehicle state quantity deriving unit 103 vehicle state quantity determining unit 104 vehicle state quantity stabilizing control unit 105 target wheel speed difference deriving unit 106 actual wheel speed difference obtaining unit 107 wheel speed difference determining unit 108 wheel speed difference direction determining unit 109 Wheel speed difference stabilization control unit 110 Braking device operation state determination unit 120 Storage unit 121 Input / output unit 130 Estimated vehicle state quantity estimation unit

Claims (9)

An actual vehicle state quantity acquisition means for acquiring an actual vehicle state quantity that is an actual vehicle state quantity of the vehicle;
Target vehicle state quantity deriving means for deriving a target vehicle state quantity that is a target vehicle state quantity;
Vehicle state quantity stabilization control, which is a control for bringing the actual vehicle state quantity close to the target vehicle state quantity by performing motion control of the vehicle when the actual vehicle state quantity and the target vehicle state quantity deviate from each other. Vehicle state quantity stabilization control means for performing
An actual wheel speed difference obtaining means for obtaining an actual wheel speed difference which is an actual wheel speed difference between left and right wheels of the vehicle;
Target wheel speed difference deriving means for deriving a target wheel speed difference which is a target wheel speed difference;
When the actual wheel speed difference deviates from the target wheel speed difference, wheel speed difference stabilization control, which is control for bringing the actual wheel speed difference closer to the target wheel speed difference by performing motion control of the vehicle. Wheel speed difference stabilization control means for ending the wheel speed difference stabilization control when the actual vehicle state quantity deviates from the target vehicle state quantity;
A vehicle stabilization control device comprising: Furthermore, an estimated vehicle state quantity estimating means for estimating an estimated vehicle state quantity based on the actual wheel speed difference is provided,
The wheel speed difference stabilization control means performs the wheel speed difference stabilization control to change the estimated vehicle state quantity to the target vehicle state quantity when the estimated vehicle state quantity deviates from the target vehicle state quantity. The vehicle stabilization control device according to claim 1, wherein the vehicle stabilization control device is moved closer to the vehicle.   3. The vehicle stabilization control according to claim 1, wherein the vehicle state quantity stabilization control and the wheel speed difference stabilization control are performed when a braking operation is performed by a driver of the vehicle. apparatus.   Furthermore, it has a braking device that applies braking force to the wheel, and the vehicle state quantity stabilization control and the wheel speed difference stabilization control control the braking force that the braking device applies to the wheel. The vehicle stabilization control device according to claim 1, wherein the vehicle stabilization control device is performed according to claim 1. The braking device applies to the wheels a plurality of braking force distribution control means capable of controlling the distribution of the braking force applied to the wheels, and a braking force equal to or greater than the braking force by a braking operation of a driver of the vehicle. Braking force assisting means capable of,
The wheel speed difference stabilization control means switches the braking force distribution control method by the braking force distribution adjustment means according to the operating state of the braking force auxiliary means during the wheel speed difference stabilization control. The vehicle stabilization control device according to claim 4.   The braking device, when controlling the distribution of the braking force applied to the wheel during the wheel speed difference stabilization control, controls from the distribution of the braking force applied to the rear wheel among the wheels. The vehicle stabilization control device according to claim 4 or 5. The actual wheel speed difference acquisition means is provided so as to be able to acquire the actual wheel speed difference of the front wheels and the actual wheel speed difference of the rear wheels of the wheels,
When the braking device controls the distribution of the braking force applied to the wheels during the wheel speed difference stabilization control, the braking force distribution applied to the front wheels is controlled by the actual wheel speed of the front wheels. The control of the distribution of the braking force applied to the rear wheel is performed based on the difference, and the control of the distribution of the braking force applied to the rear wheel is performed based on the actual wheel speed difference of the rear wheel. Vehicle stabilization control device.   The vehicle further includes a steering assist device that generates a steering assist force when the driver of the vehicle steers the wheel, and the vehicle state quantity stabilization control and the wheel speed difference stabilization control include the steering assist. The vehicle stabilization control device according to claim 1, wherein the vehicle stabilization control device performs control by controlling the steering assist force generated by the device. The front wheel is a steerable wheel that can be steered by the driver among the front and rear wheels,
The actual wheel speed difference acquisition means is provided so as to be able to acquire the actual wheel speed difference of the front wheel and the actual wheel speed difference of the rear wheel of the wheels,
9. The vehicle stabilization control device according to claim 8, wherein the steering assist device generates the steering assist force based on the actual wheel speed difference of the front wheels during the wheel speed difference stabilization control.

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