JP2009051370A - Brake control device of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for a hydropneumatic braking device of a vehicle which is comprised so as to quickly perform behavior control for suppressing excessive rolling or overturn. <P>SOLUTION: The brake control device of the vehicle includes a behavior control means for suppressing the excessive rolling of the vehicle, and a drive slip control means for suppressing excessive drive slips of driving wheels of the vehicle. The brake control device is characterized in that the drive slip control means is prohibited from performing the precharge control of the brake device when the behavior control means selectively activates the brake device of each wheel. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control device for a hydraulic (hydraulic or pneumatic) braking device for a vehicle such as an automobile, and more specifically, vehicle behavior control and drive slip control (traction) that stabilize the behavior during vehicle travel. Control-TRC) is related to brake pressure control of the braking device.

  In many braking systems for vehicles such as automobiles, an electronically controlled fluid pressure braking system (ECB), that is, fluid pressure is applied to a fluid pressure braking device or wheel cylinder provided on each wheel under the control of an electronic control device. A braking system of a type in which a fluid pressure (hydraulic pressure, pneumatic pressure, etc.) that is boosted by a pump is selectively applied to generate a force for braking the rotation of the wheel is employed. According to such a braking system, the braking force of each wheel of the vehicle can be adjusted independently. Therefore, in such a fluid pressure type braking system, the braking force of each wheel is individually controlled to give a braking force difference between the left and right wheels or the front and rear wheels to generate a yaw moment in the vehicle, and the behavior of the vehicle in the yaw direction or roll direction. It has been proposed and realized to execute behavior control that stabilizes (especially turning behavior) and wheel slip control that suppresses excessive slip of each wheel, for example, traction control and ABS control. Each wheel braking force control for performing the behavior control or wheel slip control as described above has been executed individually before, but those controls are realized by the braking system of the same vehicle. A VDIM (Vehicle Dynamical Integrated Management) system that determines the braking force distribution in the vehicle and controls the operation of the braking device of each wheel has been proposed and realized.

By the way, in the case of the fluid pressure braking system as described above, since a finite time is required until the braking force actually reaches a level effective for the control purpose after the control command is given to the braking device, a control request is generated. After that, there will be a delay until the control action becomes effective. Such control delays include, for example, control for suppressing excessive rolling of the vehicle or preventing rollover (decelerating the vehicle and applying braking force to the front wheels or turning outer wheels of the vehicle to turn the vehicle in the understeer direction. By generating a yaw moment that is applied, it is necessary to execute an urgent control such as a control that reduces the centrifugal force acting on the vehicle and suppresses excessive rolling to prevent vehicle rollover (rollover). In particular, it is not preferable. Therefore, if a situation requiring such behavior control is approaching or a sign is detected before behavior control is truly necessary, the wheel braking device to be controlled when the behavior control is executed. Selectively, it is proposed that pre-charge control is performed so that the braking force reaches the desired level immediately when pressure is applied at a low level in advance and behavior control by the braking force is required. (For example, refer to Patent Document 1). Also, in the case of traction control, in order to improve the responsiveness, it is selectively reduced in advance to the wheel braking device to be controlled when the sign appears before it becomes necessary to suppress excessive driving slip. There is a case where precharge control for applying pressure at a level is executed.
Special table 2007-513002

  In the fluid pressure braking system as described above, the behavior control for suppressing excessive rolling and the drive slip control may be executed simultaneously. In that case, when the wheel to which the braking force is to be applied based on the behavior control and the wheel to which the braking force is to be applied based on the TRC are different, the number of wheel cylinders to be increased at the same time increases. The increase rate of the fluid pressure delivered from the pressure pump is reduced, and an increase in delay from when the above control request is generated until the control becomes effective may occur. Of course, both behavioral control and drive slip control should eventually be achieved if necessary, and both controls can be performed simultaneously by using a pump with a corresponding output or capacity. is there. However, behavior control for preventing excessive rolling or rollover may be urgent. Therefore, as described above, when the occurrence of excessive rolling is predicted, control is performed in order to accelerate the achievement of behavior control. When precharge is executed to increase the brake pressure for the target wheel at a low level, the wheel cylinder of the wheel subject to drive slip control is in communication with the fluid pressure pump (even if intermittent) When this occurs, the response speed of the wheel that is subject to behavior control decreases, and the effect of precharging is reduced. In the conventional hydraulic braking system, as described above, in the situation where behavior control for suppressing excessive rolling or preventing rollover and driving slip control such as TRC are performed simultaneously, the control response speed is There seems to be no proposal for a control configuration that takes account of the decline.

  Thus, an object of the present invention is a control device for a hydraulic braking device capable of performing behavior control and driving slip control for suppressing excessive rolling or rollover during turning of a vehicle. An object of the present invention is to provide an apparatus configured to quickly execute behavior control for suppressing rollover.

  Another object of the present invention is a control device as described above, wherein behavior control for suppressing excessive rolling or rollover and drive slip control require generation of braking force on separate wheels at the same time. In an obtained situation, it is to provide a device configured to prioritize the generation of braking force by behavior control.

  Furthermore, another object of the present invention is a vehicle control device as described above, which is an effect of behavior control that suppresses excessive rolling or rollover due to a response delay of each wheel brake pressure with respect to a control command of a hydraulic brake device. It is an object of the present invention to provide a device configured to prevent the occurrence of the occurrence of delay.

  According to the present invention, in short, in the control device of the fluid pressure circuit for the braking device of the vehicle, when the excessive rolling or rollover suppression behavior control of the vehicle is executed or preload control (pre- Charge control) is executed in preference to driving slip control such as traction control, thereby providing an apparatus configured to quickly exhibit the effect of excessive rolling or rollover suppression behavior control.

  The vehicle braking control device of the present invention is applied to a vehicle having a braking system in which the braking force of each wheel can be independently controlled by a fluid pressure braking device. The braking control device of the present invention includes, as one aspect, behavior control means for suppressing excessive rolling of the vehicle and drive slip control means for suppressing excessive drive slip of the drive wheels of the vehicle. When the brake device for each wheel is selectively operated for behavior control by the control means, precharge control of the brake device for drive slip control by the drive slip control means is prohibited.

  Here, the “behavior control for suppressing excessive rolling” may be any known type of behavior control for suppressing excessive rolling or suppressing rollover. In this control, a braking force is applied to the front wheel of the vehicle or the front wheel outside the turn to generate a yaw moment that turns the vehicle outward in the turn, thereby reducing the centrifugal force acting on the center of gravity of the vehicle. It's okay. The “drive slip control” is a control that reduces the wheel speed by applying a braking force so that the drive slip amount or the slip rate does not become excessive in each of the drive wheels in any known type. It's okay. “Precharge control of braking device for driving slip control by driving slip control means”, as already mentioned, the driving wheel holds the gripping force, but the driving slip amount increases considerably, and the driving slip When it is determined that the condition that really requires control is approaching, brake pressure is supplied to the braking device corresponding to the drive wheel at a low level, and drive slip control is truly required When the state is reached, the control is performed so that the brake pressure can quickly reach the target pressure corresponding to the target braking force.

  According to the braking control device of the present invention described above, if necessary, behavior control for suppressing excessive rolling is executed, and a selected wheel of the vehicle (typically, the front wheels or both front wheels outside the turn). ) Is increased, precharge control for driving slip control is prohibited. As already mentioned, behavior control for suppressing excessive rolling is one of the controls that need to exhibit the control effect as quickly as possible. For this reason, in order to speed up the control response (for behavior control) Up to pre-charge control). However, if the driving slip control or the precharge control for the wheel different from the wheel to which the braking force is applied by the behavior control is executed, the braking of the wheel subject to the driving slip control is performed. The brake pressure supplied to the device also increases the number of braking devices or the number of flow paths to be supplied with pressure, and therefore the response speed of the wheel braking device to which braking force is applied in behavior control. In particular, there is a possibility that the boosting speed becomes slow and the generation of the control effect of the behavior control is delayed. On the other hand, the control itself that avoids the state in which the drive slip control is truly necessary, that is, the state in which the tire of the drive wheel loses the gripping power should be surely executed, but the precharge control for the drive slip control In such a situation, since the driving wheel still holds the gripping force, the stability of the vehicle does not deteriorate rapidly even if the execution of the control is prohibited. Therefore, in the braking device of the present invention, when behavior control for suppressing excessive rolling or precharge control for the same is executed, precharge control for driving slip control is prohibited, and behavior control is performed. Thus, an attempt is made to reduce the chance that the response speed of the braking device for the wheel to which the braking force is applied decreases. In other words, behavior control has priority over precharge control for drive slip control. In addition, when the drive slip control is really necessary, the drive slip control may not be prohibited because the control should be executed.

  In the embodiment, the selective operation of the braking device of each wheel by the behavior control means that suppresses excessive rolling, that is, behavior control is typically performed by the vehicle roll state index value, that is, the vehicle It may be executed when an arbitrary index value representing the roll state exceeds the first determination reference value. The precharge control of the braking device for each wheel by the behavior control means is executed when the roll state index value of the vehicle exceeds a second determination reference value that is lower than the first determination reference value. Good (when the roll state index value of the vehicle exceeds the first determination reference value, the behavior control exceeds the precharge control and is executed as it is). The control device of the present invention is characterized in that, in the embodiment, the precharge control of the braking device by the driving slip control means is prohibited while the behavior control as described above or the precharge control therefor is executed. Will be configured.

  In the above configuration, it should be understood that the roll state index value is referred to in order to determine the magnitude of the centrifugal force acting on the center of gravity of the vehicle. Or, in other words, it may be an arbitrary value that is referred to in order to determine the risk of rollover when the vehicle turns. Therefore, the roll state index value includes the lateral acceleration, yaw rate of the vehicle actually detected or estimated in the vehicle, the ground load difference or ground load ratio of the left and right wheels of the vehicle, the roll angle of the vehicle, the roll rate, It may be at least one value selected from the group consisting of a steering angle and a steering angular velocity, or a combination thereof. In particular, when the theoretical value of the steering angle, the steering angular velocity, or the yaw rate or lateral acceleration determined therefrom is selected as the roll state index value, those values are used as the steering input based on the driver's steering input. Correspondingly, it is possible to estimate that the centrifugal force can be excessive before it actually occurs.

  In the embodiment of the control device of the present invention described above, the determination of the roll state index value is, as one object, the determination of whether or not behavior control for preventing rollover of the vehicle should be executed. Therefore, the first criterion value for the roll state index value is the unit of the selected value of the various roll state index values listed above for the static rollover limit lateral acceleration of the vehicle. It may be determined based on the value converted into. Specifically, the determination reference value may be set to a value lower than the value corresponding to the static rollover limit lateral acceleration so that the actual lateral acceleration does not reach the static rollover limit lateral acceleration. preferable. In addition, since the second criterion value is for determining whether or not the state in which behavior control for preventing the vehicle rollover is to be executed is approaching, the first criterion value is It becomes the value which lowered the level arbitrarily.

  By the way, in the braking control device of the present invention described above, the fluid pressure braking device for the wheel to be subjected to behavior control for suppressing excessive rolling and the fluid pressure braking device for the wheel to be subject to drive slip control are in fluid communication. The invention is particularly advantageously applied in a fluid pressure circuit having such a configuration. Therefore, typically, the braking system of the vehicle may be a cross piping type braking system. However, when the brake pressure of the braking device for all wheels is controlled by receiving an output from one pump or a pressure supply source, or when the fluid pressure circuit is subject to behavior control for suppressing excessive rolling. Power supply for a pump or pressure supply source that supplies brake pressure to each brake device, although the hydraulic brake device and the hydraulic brake device of the wheel subject to drive slip control are not in fluid communication with each other. It should be understood that the advantages or effects of the present invention as described above can be obtained even when applied to a configuration having a common source, and such cases are also within the scope of the present invention.

  Briefly speaking, the braking control device according to the present invention is a single hydraulic braking system in which the braking force can be adjusted independently for each wheel, and when the braking force adjustment control is executed for a plurality of purposes. It can be said that priority is set in view of the purpose of each control, and this is one example of avoiding control interference when a plurality of objective braking force adjustment control execution requests occur simultaneously. In particular, in the braking control of the present invention, regarding the excessive rolling suppression control and the precharge control of the drive slip control, if both controls are executed, the effects of both controls are effective. Both may be reduced. However, according to the present invention, in view of the urgency or importance of excessive rolling suppression control, priority is given to excessive rolling suppression control, and the effect is quickly exhibited, so that the vehicle can be as reliably as possible. The behavior will be stabilized. In this case, the execution of the precharge control of the drive slip control is prohibited, but the control of the drive slip control itself is not prohibited, and the vehicle is also decelerated by the behavior control. When behavior control is executed prior to drive slip control, there is little chance that the drive slip control will be required suddenly. The impact of will not be significant.

  Other objects and advantages of the present invention will become apparent from the following description of preferred embodiments of the invention.

Configuration of Device FIG. 1 (A) a car that preferred embodiments of the brake control apparatus of the present invention is incorporated is shown schematically. In the figure, the vehicle 10 having the left and right front wheels 12FL and 12FR and the left and right rear wheels 12RL and 12RR is arranged in a normal manner according to the depression of the accelerator pedal by the driver (in the illustrated example, A drive system 20 that generates braking / driving force on all wheels because it is a four-wheel drive vehicle, and a steering device 30 for controlling the steering angle of the front wheels (further, a steering device for the rear wheels is provided) And a braking system device 40 that generates a braking force on each wheel. In the driving system device 20, the driving torque or rotational driving force from the engine and / or the electric motor 21 is transmitted to the center differential (or transfer) 26 via the transmission (transmission) 22 in the normal manner, and further, the front wheels It is transmitted to the front wheels 12FL, 12FR and the rear wheels 12RL, 12RR via the side differential 24 and the rear wheel side differential 28, respectively. The steering device transmits the rotation of the steering wheel 32 operated by the driver to the tie rods 36L and 36R while boosting the rotational force by the booster 34, and steers the front wheels 12FL and 10FR. It may be.

  The braking system device 40 is provided in a wheel cylinder 42FL, 42FR, 42RL, 42RR mounted on each wheel by a hydraulic circuit 46 that communicates with a master cylinder 45 that is operated in response to depression of a brake pedal 44 by a driver. This is an electronically controlled hydraulic brake device in which the brake pressure, that is, the braking force in each wheel is adjusted. FIG. 2A shows a schematic diagram of a typical example of the piping configuration inside the hydraulic circuit 46. Referring to the figure, hydraulic circuit 46 has a cross-pipe configuration, circuit 46A for controlling the brake pressures of left front wheel and right rear wheel wheel cylinders 42FL, 42RR, right front wheel and left rear wheel. Includes a circuit 46B that controls the brake pressure of the wheel cylinders 42FR, 42RL of the wheel (the two circuits may have the same piping structure unless otherwise indicated), and in normal operation the brake pedal In response to the depression of 44, the pressure of the master cylinder 45 is supplied to each wheel cylinder 42i (i = FL, FR, RL, RR) via the circuits 46A, 46B. On the other hand, when adjusting the braking force of each wheel individually or independently to execute behavior control, traction control (TRC) by each wheel braking force control, or other electronic control, it is based on a command of the electronic control unit 60. Then, the master cylinder cut valves 50A and 50B directly connected to the master cylinders of the circuits 46A and B are closed, and the hydraulic pumps 52A and 52B provided in the hydraulic circuit are operated to operate the master cylinder cut valves 50A and 50B. The hydraulic pressure between 50B and the wheel cylinder 42i of each wheel is increased. The wheel cylinder 42i of each wheel is provided with a hydraulic pressure holding valve 54i on the hydraulic pump 52A, B side and a pressure reducing valve 58i on the buffer reservoir 56A, B side, respectively, to increase the hydraulic pressure of the wheel cylinder of each wheel. When the pressure is applied, the hydraulic pressure holding valve 54i is opened and the wheel cylinder receives the pressure from the pump and expands. As a result, a brake pad (friction element) (not shown) is applied to the brake disc inside the wheel. When the brake pressure is reduced, the pressure reducing valve 58i is opened to release the pressure to the reservoir. The actual value of the brake pressure in the wheel cylinder of each wheel is referred to based on the detected value of a corresponding pressure sensor (not shown), and is controlled to match each target pressure. The braking system device 40 may be of a type that applies a braking force to each wheel pneumatically or electromagnetically, or any other type for those skilled in the art.

  Referring to FIG. 1A again, the behavior control and the operation control of the braking system device 40 of the present invention are executed by the electronic control device 60 as already mentioned. The electronic control unit 60 may include a microcomputer and a drive circuit having a CPU, a ROM, a RAM, and an input / output port device which are connected to each other by a bidirectional common bus. In the figure, the electronic control unit 60 receives the brake pedal depression amount θb, the steering angle δ, the wheel speed Vwi, the pressure Pbi in the wheel cylinder of each wheel, and the lateral acceleration Gy from sensors provided in each part of the vehicle. However, various parameters necessary for various controls to be executed in the vehicle of the present embodiment, for example, various detections such as front and rear G sensor values and yaw rate sensor values are illustrated. A signal may be input.

Overview of the control operation According to the hydraulic circuit described above, the brake pressure in each wheel cylinder can certainly be adjusted individually, but in the circuits 46A and 46B, the two wheels connected respectively. When the cylinders are required to increase the brake pressure at the same time, the pressure increase speed can be slower than when only one wheel cylinder is required to increase the pressure. For example, as illustrated in FIG. 2B, when the behavior control for reducing excessive rolling or the precharge control for the excessive rolling is executed during the left turn of the vehicle, the braking force of the right front wheel 12FR is set. In order to increase, the brake pressure of the wheel cylinder is increased. At this time, if TRC or precharge control therefor is executed in the left rear wheel 12RL, the pump 52B supplies brake pressure to the wheel cylinder of the left rear wheel 12RL. May increase and the overall boosting speed in the circuit 46B may decrease. When this happens, the increase in brake pressure for behavior control or precharge control therefor is delayed, and as a result, generation of braking force of the right front wheel 12FR for behavior control for suppressing excessive rolling that may require abruptness is generated. It can be late. Conversely, when performing behavior control or precharge control therefor, closing the wheel cylinder valve of a wheel that is not subject to behavior control or precharge control within the same circuit will increase the brake pressure. It will be possible to execute more quickly.

  As mentioned in the disclosure section of the invention, it should be avoided that the driving wheel loses the gripping force. However, when the precharge control for TRC is executed, the driving wheel still has the gripping force. It is in a held state. On the other hand, suppression of excessive rolling has the purpose of preventing the vehicle from rolling over, and should be executed as quickly and preferentially as possible. Therefore, as described later, the control device of the present invention prohibits the execution of the precharge control for the TRC during the behavior control for suppressing excessive rolling or the precharge therefor, The wheel cylinder is configured to be quickly boosted for behavior control or precharging therefor. It should be understood that, normally, both the behavior control for suppressing excessive rolling and the TRC are executed after the precharge is first executed. Therefore, when the TRC main control is already executed at the start of the behavior control execution, it is assumed that the pressure in the circuit is considerably increased, so the TRC main control is not prohibited. Also good. Further, when it is necessary to execute the TRC main control, the driving wheel loses the grip force as it is, so that the TRC main control may be executed as it is. Of course, if the behavior control is started first, the vehicle is decelerated (deceleration control is started separately from the control that generates the yaw moment), and therefore it is necessary to execute the TRC main control. Is less likely to occur.

Device operation
(A) Control Configuration FIG. 1B shows the configuration of the control device of the present invention in the form of control function blocks. The illustrated control configuration may be realized by executing a program stored in advance in the electronic control device 60 of FIG. Further, the operation of the control device may always be executed while the vehicle is traveling. Referring to FIG. 1B, in the control device of the present invention, the target value of the braking force for each wheel determined by each wheel braking force distribution determination unit 60a is a control command including precharge control. It is converted into a control command to the hydraulic circuit 46 via the determination unit 60b, and thus the braking device of each wheel, that is, the brake pressure of the wheel cylinder is controlled.

  In the above-described configuration, each wheel braking force distribution determining unit 60a, like a so-called VDIM system, performs various arbitrary braking force distribution controls known in this field, for example, the yaw behavior (understeer tendency or Control of yaw behavior such as VSC (Vehicle Stability Control) that controls yaw rate by generating yaw moment that corrects oversteer tendency), roll suppression behavior control that prevents rolling of the vehicle by suppressing excessive rolling Integrate requests such as TRC and ABS control for adjusting wheel speed to suppress excessive wheel slip, and determine a target value of braking force for each wheel in a control device that controls braking force for each wheel. It may be like this. In particular, the control relating to the characteristics of the control device of the present invention is roll suppression control and TRC among the various controls listed above.

  Roll suppression behavior control, in any known manner, when it is detected that the rolling of the vehicle is excessive or when it is estimated, braking force is generated on the front wheels or both front wheels outside the turn, The vehicle is decelerated or the yaw moment is generated so that the vehicle turns in the direction of understeer, thereby reducing the centrifugal force acting on the center of gravity of the vehicle. Therefore, in the present embodiment, when the roll restraining behavior control is executed, the target value of the braking force of the front non-turning wheel or both front wheels is determined in each wheel braking force distribution determination unit 60a. It becomes. The detection that the rolling of the vehicle has become excessive or the estimation thereof may be executed in a known manner. Typically, however, an index value indicating a roll state (roll state index value) is a predetermined criterion value. It is performed by determining whether or not it exceeds. For example, when the lateral acceleration Gy is adopted as the roll state index value, the absolute value of the lateral acceleration Gy is compared with a predetermined determination reference value Gyth1, and when Gy> Gyth1 is satisfied, rolling of the vehicle is performed. It is excessive, and it may be determined that roll suppression behavior control is necessary. The determination reference value Gyth1 may be set to a value lower than the static rollover limit lateral acceleration by an arbitrary predetermined width in consideration of vehicle safety. As shown in FIG. 3, the static rollover limit lateral acceleration is a lateral acceleration that becomes a limit at which the direction of the resultant force of centrifugal force and gravity starts to turn to the side of the vehicle at the center of gravity of the vehicle. Tr / 2) / h · g (h and g are the height of the center of gravity and the acceleration of gravity, respectively).

  The roll state index value may be any amount as long as the value of the centrifugal force acting on the vehicle can be estimated. For example, when the roll sensor is provided in the vehicle, The roll angle or roll rate of the vehicle may be referred to, and when each wheel is provided with a ground load sensor, the ground load difference or load ratio between the left and right wheels may be referred to. Further, steering angle, steering angular velocity, and yaw rate may be referred to. When a yaw rate sensor is provided, the lateral acceleration Gy may be given by Gy = γa · Vx (Vx is a vehicle speed and may be arbitrarily determined based on wheel speed or the like). When the roll state index value is an amount other than lateral acceleration, the static rollover limit lateral acceleration is converted into a value adopted as the roll state index value, and the determination reference value is determined based on the converted value. Good.

  The TRC may be the same as that executed in any known manner, and typically, for each wheel, the difference between the wheel speed and the vehicle speed (ie, the slip amount) or the difference in the vehicle speed. The divided value (slip rate) is calculated, and when a slip amount or slip rate Si exceeds a predetermined threshold value Sth for a certain drive wheel, a braking force is applied to reduce the wheel speed. Therefore, in this embodiment, when TRC is executed, the braking force target for the wheels whose slip amount or slip ratio exceeds a predetermined threshold in each wheel braking force distribution determination unit 60a. The value will be determined. The vehicle body speed may be determined by the smallest value of wheel speeds or any other method known in this field. When some wheels are in a rolling state, the wheel speed may be selected as the vehicle body speed.

(B) Precharge Control The output of each wheel braking force distribution determining unit 60a, that is, the target braking force value of each wheel is transmitted to the control command determining unit 60b. Therefore, the control command determining unit 60b basically uses the brake pressure corresponding to the target braking force value in the wheel cylinder of each wheel in any known manner based on the target braking force value of each wheel. A control command is sent to each part of the hydraulic circuit to achieve the above. However, in the control device of the present embodiment, with reference to the roll state index value of the vehicle and the slip amount or slip ratio of each wheel, even if there is no need to perform roll suppression behavior control or TRC, When it is determined that the necessary state of execution of these controls is imminent, brake pressure is supplied to the wheel cylinder at a lower level than when normal roll suppression behavior control or TRC is executed (pre- Charge), the target braking force can be quickly achieved when each control needs to be executed. In this regard, the precharge for controlling the roll suppression behavior and the precharge of the TRC may be performed in any known manner, but as understood from the above description, While precharge or this control is being executed, execution of TRC precharge is prohibited.

  FIG. 4 shows the control processing by the control command determination unit 60b in the form of a flowchart.

  With reference to the figure, in the control command determination unit 60b, first, referring to the roll state index value of the vehicle, whether or not the situation where the roll suppression behavior control needs to be executed is approaching. Is determined (step 10). Such determination may be performed by determining whether or not the roll state index value of the vehicle exceeds a predetermined determination reference value, as in the determination of whether or not to perform roll suppression behavior control. However, since the determination result referred to by the control command determination unit 60b is whether or not the situation where the roll suppression behavior control needs to be executed is approaching, the determination reference value is determined by each wheel braking force distribution determination unit 60a. A criterion value Gyth2 smaller than the criterion value Gyth1 used is used. Specifically, as the calculation processing, when the lateral acceleration is adopted as the roll state index value, as illustrated in FIG. 1B, the absolute value | Gy | of the lateral acceleration acquired from the lateral acceleration sensor and When the difference ΔGy from the determination reference value Gyth2 is calculated and ΔGy> 0 is established, it may be determined that the situation where the roll suppression behavior control needs to be executed is approaching.

When it is determined that ΔGy> 0 is satisfied and the situation where the roll suppression behavior control needs to be executed is approaching, the brake device (wheel cylinder) for the roll suppression behavior control is precharged. Therefore, correction of the target braking force value of the front non-turning wheel (or both front wheels) out of the target braking force value from each wheel braking force distribution determining unit 60a is executed (step 50). Specifically, the target braking force value of the front wheels outside the turn or both front wheels is reset by the following equation.
Fbtfo ← Max {Fbfo, Fbpre} (1)
(Fbtfi ← Max {Fbfi, Fbpre})
Here, Fbfo and Fbfi are target braking force values of the front wheels outside the turn and the front wheels inside the turn by each wheel braking force distribution determination unit 60a, Fbpre is a braking force value corresponding to the precharge brake pressure, and Fbtfo and Fbtfi. Is a target value of the braking force to be realized by a control command to the hydraulic circuit. Note that Max is an operator that selects the larger one of the values in parentheses. Further, the resetting by the second equation may or may not be arbitrarily executed.

  Thus, according to the resetting of the target braking force value according to the equation (1), each wheel braking force distribution determination unit 60a is not required to perform roll suppression behavior control or TRC (in this case, Fbfo˜0). , Fbfi to 0), when the situation requiring execution of the roll suppression behavior control is approaching, Fbpre is selected as Fbtfo, Fbtfi, that is, the target braking force value of the front non-turning wheel or both front wheels is pre- The braking force value corresponding to the charge is raised. On the other hand, when roll suppression behavior control or TRC execution is requested in each wheel braking force distribution determination unit 60a, the target braking forces Fbo and Fbi determined in each wheel braking force distribution determination unit 60a are used as they are. The final target braking force values Fbtfo and Fbtfi for the front wheels outside the turn or both front wheels are adopted. It should be noted that ΔGy> 0 is normally established when execution of roll suppression behavior control is required.

  In step 10, when ΔGy> 0 is not established, it is determined whether or not the situation that requires execution of TRC is approaching (step 20). This determination may be made by determining whether the driving slip amount or the slip ratio Si exceeds a predetermined threshold for each wheel of the vehicle, as in the determination of whether or not to execute TRC. However, in this case as well, as in Step 10, the determination result referred to by the control command determination unit 60b is whether or not the situation that requires execution of TRC is imminent. A determination threshold value Sth2 smaller than the determination threshold value Sth1 used in the power distribution determination unit 60a is used. Specifically, as exemplified in FIG. 1 (B), the calculation processing includes the driving slip amount Si and the determination threshold value Sth2 from each wheel speed value determined based on the wheel speed sensor value Vwi of each wheel. When the difference ΔSi is calculated and ΔSi> 0 is established, it may be determined that the situation where the TRC needs to be executed is approaching. Although omitted in the figure for simplicity, this determination is performed for all of the drive wheels of the vehicle.

When it is determined that ΔSi> 0 is satisfied and the situation where TRC needs to be executed is approaching, a braking device for a wheel that satisfies ΔSi> 0, that is, a wheel that can be a target of TRC ( In order to execute the precharge of the wheel cylinder), correction of the target braking force value from each wheel braking force distribution determining unit 60a for the wheel is executed (step 40). Specifically, the target braking force value of the target wheel is reset by the following equation.
Fbti ← Max {Fbi, Fbpre} (2)
Here, Fbi is a target braking force value by each wheel braking force distribution determining unit 60a, Fbpre is a braking force value corresponding to the precharge brake pressure, and Fbti should be realized by a control command to the hydraulic circuit. This is the target value of braking force. In addition, when there are a plurality of wheels in which ΔSi> 0 is established (which may be a target of TRC), the processing according to the expression (2) is performed for all of them.

  Thus, in the case of resetting the target braking force value according to the expression (2), when each wheel braking force distribution determining unit 60a does not require the roll suppression behavior control or the TRC execution (in that case, Fbi˜ 0) Fbpre is selected as Fbti for a wheel that is determined to be in a state where the TRC needs to be executed, and the target braking force value of the wheel reaches a braking force value equivalent to precharge. Will be lifted. On the other hand, when the execution of TRC is requested in each wheel braking force distribution determination unit 60a, the target braking force Fbi determined in each wheel braking force distribution determination unit 60a is directly used as the final target braking force value. Adopted as Fbti.

  However, as understood from the flowchart shown in the figure, TRC precharge is executed only when ΔGy> 0 is not satisfied, so when either roll suppression behavior control or precharge control therefor is executed. Therefore, the precharge for the TRC is prohibited, and therefore the response speed of the brake pressure for the roll suppression behavior control or the precharge control for the roll suppression behavior control is improved.

  When neither ΔGy> 0 nor ΔSi> 0 holds, the target value of the braking force of each wheel braking force distribution determination unit 60a is used as it is as the final target value as understood from FIG. 4 (step 30). . Then, a control command to the hydraulic circuit is generated in any known manner so that the final target value determined in any of steps 30 to 50 is achieved, and each part of the hydraulic circuit is generated according to the control command. (However, when neither ΔGy> 0 nor ΔSi> 0 holds, the target braking force value is approximately zero for all wheels unless there is any other braking force control or brake pedal depression.)

  While the present invention has been described in detail with respect to one embodiment thereof, it will be apparent to those skilled in the art that various modifications can be made within the scope of the present invention.

  For example, in the above embodiment, the precharge is executed when ΔGy> 0 or ΔSi> 0 is satisfied, but ΔGy> 0 or ΔSi> 0 is once satisfied. From the time or when ΔGy> 0 or ΔSi> 0 is not established, it may continue for a predetermined time. Alternatively, the judgment reference value or judgment threshold value for releasing the precharge may be set lower than the judgment standard value or judgment threshold value for starting the precharge. According to these configurations, it is possible to prevent precharge on / off chattering. Further, in the illustrated example, the determination of whether or not the situation requiring the roll suppression behavior control is approaching is based on the determination of the magnitude of the roll state index value such as the lateral acceleration. When emergency steering is detected at, precharge for roll suppression behavior control may be executed.

FIG. 1A is a schematic diagram of a vehicle on which a preferred embodiment of the braking control device of the present invention is mounted, and FIG. 1B is an electronic control that realizes the preferred embodiment of the braking control device according to the present invention. It is a control block diagram of an apparatus. FIG. 2A is a schematic diagram of a piping configuration of a hydraulic braking device controlled by the braking control device of the present invention. In the figure, the master cylinder cut valves 50F and 50R and the hydraulic pressure holding valve 54i are normally open solenoid valves, and the pressure reducing valve 58i is a normally closed solenoid valve. In FIG. 2, the setting of each valve is in a state where electronic control of braking force is not performed. FIG. 2 (B) is a schematic diagram of a vehicle showing wheels connected to one circuit in the hydraulic circuit configuration of (A). FIG. 3 is a schematic view seen from the front-rear direction of the vehicle for explaining the calculation of the static rollover limit lateral acceleration. If the resultant force further shifts to the side of the vehicle, there is a risk of rollover. FIG. 4 is a flowchart showing the precharge control process in the control command determination unit of the braking control apparatus according to the embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Vehicle 20 ... Drive system device 30 ... Steering device 40 ... Braking system device 42FL-42RR ... Braking device (wheel cylinder)
46 ... Hydraulic circuit 44 ... Brake pedal 60 ... Electronic controller 62 ... Lateral acceleration sensor

Claims (6)

  A vehicle braking control device having a braking system in which the braking force of each wheel can be independently controlled by a fluid pressure braking device, and behavior control means for suppressing excessive rolling of the vehicle and excessive driving wheels of the vehicle Drive slip control means for suppressing a drive slip, and when the brake device for each wheel is selectively operated for behavior control by the behavior control means, the drive slip control means drives A device for prohibiting precharge control of the braking device for slip control.   The apparatus according to claim 1, wherein when the roll state index value of the vehicle exceeds a first determination reference value, the braking device for each wheel is selectively operated by the behavior control means, and the driving slip control is performed. A device characterized in that precharge control of the braking device for is prohibited.   3. The apparatus according to claim 2, wherein the behavior control is performed when a roll state index value of the vehicle exceeds a second determination reference value lower than the first determination reference value and lower than the first determination reference value. The precharge control for the wheel is selectively executed for the brake device of each wheel, and the precharge control of the brake device for the drive slip control is prohibited.   3. The apparatus according to claim 2, wherein the first determination reference value is determined based on a static rollover limit lateral acceleration of the vehicle.   The apparatus according to claim 2, wherein the roll state index value is a lateral acceleration of the vehicle, a yaw rate, a ground load difference or a ground load ratio of the left and right wheels of the vehicle, which is actually detected or estimated in the vehicle. The apparatus is at least one value selected from the group consisting of a roll angle of the vehicle, a roll rate, a steering angle of the vehicle, and a steering angular velocity.   2. The apparatus according to claim 1, wherein the braking system of the vehicle is a cross piping type braking system.

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