JP4304259B2 - Brake control device for vehicle - Google Patents

Description

  The present invention relates to a vehicular braking control apparatus, and is particularly useful when a driver is going to make a spin turn.

Conventionally, there has been an electric brake that combines a main brake and a parking brake (see Patent Document 1).
JP-A-11-321599

  If, for example, anti-skid control is performed on the electric brake as in the above-described conventional example regardless of whether it is a main brake operation or a parking brake operation, the driver intentionally skids the rear wheel by the parking brake operation. Even if you try to make a so-called spin turn that changes the direction of the vehicle body (also called a side turn because it uses a side brake), the anti-skid control that suppresses the braking force is activated and the wheel lock is prevented. There is a problem that the spin turn that the driver wants cannot be done.

  Accordingly, the present invention has been made paying attention to the above-mentioned problems, and an object of the present invention is to provide a vehicle brake control device that can realize a spin turn desired by the driver.

  In order to solve the above problems, the vehicle braking control device according to the present invention suppresses the tendency of the wheels to lock against the wheels to which braking force is applied by the driver's parking brake operation. It is characterized in that it is determined whether or not the driver is requesting a spin turn accompanied by a parking brake operation, and if it is determined that the driver is requesting a spin turn, suppression of wheel lock tendency is limited.

  Here, the spin turn is a driving technique in which the driver intentionally slides the rear wheel by the parking brake operation to change the direction of the vehicle body.

  According to the vehicle brake control device of the present invention, it is determined whether or not the driver requests a spin turn accompanied by a parking brake operation, and if it is determined that the driver requests a spin turn, the wheel lock is performed. By restricting the suppression of the tendency, when the driver tries to perform a spin turn by the parking brake operation, the tendency of the wheels to lock can be allowed, so that a spin turn desired by the driver can be realized. In addition, when the driver is trying to perform normal grip driving, that is, when it is determined that the driver does not require a spin turn, if a wheel lock tendency is detected, this is due to parking brake operation. The normal control is executed, and safety can be ensured by reliably suppressing the wheel lock tendency. That is, while suppressing the tendency of the wheel lock due to the parking brake operation in normal times, the wheel lock tendency is allowed and the spin turn can be realized only when necessary, that is, when the driver requests the spin turn. .

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, which controls the braking force of the front wheels 1FL and 1FR according to the driver's main brake operation, and also according to the driver's main brake operation and parking brake operation. This is a brake-by-wire that controls the braking force of the rear wheels 1RL and 1RR. That is, the stroke sensor 4 and 5 detect the operation amount S _M of the brake pedal 2 that is the main brake operation and the operation amount S _P of the parking lever 3 that is the parking brake operation, respectively, and the controller 6 detects each brake operation amount. In accordance with S _M and S _P , the brake actuator 7 composed of a hydraulic control circuit is driven and controlled, and a desired hydraulic pressure is supplied to the wheel cylinders 8FL to 8RR of each wheel as shown in FIG. The wheel cylinders 8FL to 8RR are incorporated in a disc brake that generates a braking force by pressing a disc rotor with a brake pad, or a drum brake that generates a braking force by pressing a brake shoe against the inner peripheral surface of the brake drum. ing.

  The front side of the brake actuator 7 is a normally open type first gate valve 10f capable of closing the flow path between the reservoir tank 9 storing brake fluid and the wheel cylinder 8FL (8FR), the first gate valve 10f and the wheel cylinder. A normally closed type inlet valve 11FL (11FR) capable of opening a flow path between 8FL (8FR), an accumulator 12f communicating between the wheel cylinder 8FL (8FR) and the inlet valve 11FL (11FR), and a wheel cylinder 8FL (8FR) ) And the accumulator 12f and a normally closed outlet valve 13FL (13FR) capable of opening the flow path, between the reservoir tank 9 and the first gate valve 10f, and between the accumulator 12f and the outlet valve 13FL (13F). ), A normally closed second gate valve 14f capable of opening a flow path communicating with each other, an accumulator 12f and an outlet valve 13FL (13FR) are connected to the suction side, and the first gate valve 10f and the inlet valve 11FL are connected. (11FR) and a positive displacement pump 15 in which the discharge side is communicated. Incidentally, a damper chamber 16 is disposed on the discharge side of the pump 15 to suppress pulsation of the discharged brake fluid and weaken pedal vibration.

  The first gate valve 10f, the inlet valves 11FL and 11FR, the outlet valves 13FL and 13FR, and the second gate valve 14f are two-port, two-position switching, single solenoid, and spring offset type electromagnetic operation valves, respectively. The gate valve 10f opens the flow path at the non-excited normal position, and the inlet valves 11FL and 11FR, the outlet valves 13FL and 13FR, and the second gate valve 14f are configured to close the flow path at the non-excited normal position. Has been. The accumulator 12f is configured by a spring-type accumulator in which a compression spring is opposed to a cylinder piston. The pump 15 is a positive displacement pump such as a gear pump, vane pump, piston pump or the like that can ensure a substantially constant discharge amount regardless of the load pressure.

  With the above configuration, when the outlet valve 13FL (13FR) is in the non-excited normal position, the first gate valve 10f is excited and closed, and the inlet valve 11FL (11FR) and the second gate valve 14f are excited. When the pump 15 is further driven, the hydraulic pressure in the reservoir tank 9 is sucked through the second gate valve 14f, and the discharged hydraulic pressure is sent through the inlet cylinder 11FL (11FR) to the wheel cylinder 8FL (8FR). ) And the pressure is increased.

  Further, when the first gate valve 10f, the inlet valve 11FL (11FR), the outlet valve 13FL (13FR), and the second gate valve 14f are all in the non-excited normal position, the reservoir cylinder 9 is moved from the wheel cylinder 8FL (8FR). And each flow path to the accumulator 12f is blocked, and the hydraulic pressure of the wheel cylinder 8FL (8FR) is maintained.

  Further, when the outlet valve 13FL (13FR) is excited and opened when the first gate valve 10f, the inlet valve 11FL (11FR) and the second gate valve 14f are in the non-excited normal position, the wheel cylinder 8FL (8FR) The fluid pressure flows into the accumulator 12f and is reduced. The hydraulic pressure flowing into the accumulator 12 f is sucked by the pump 15 and returned to the reservoir tank 9.

Thus, the controller 6, the braking force command value F _T outputted to the brake actuator 7, the first gate valve 10f, inlet valve 11FL · 11FR, outlet valve 13FL · 13FR, second gate valve 14f, and drives and controls the pump 15 By doing so, the hydraulic pressure of the wheel cylinders 8FL and 8FR on the front side is increased, held and reduced.
Next, the rear side includes the same first gate valve 10r, inlet valve 11RL / 11RR, outlet valve 13RL / 13RR, second gate valve 14r, pump 15 and damper chamber 16 as the front side. Detailed description thereof is omitted. Further, the drive control of the first gate valve 10r, the inlet valves 11RL and 11RR, the outlet valves 13RL and 13RR, the second gate valve 14r, and the pump 15 is the same as that on the front side, and detailed description thereof is omitted. .

In this embodiment, a front / rear split method is used in which the hydraulic pressure supply path from the reservoir tank 9 is divided into a front and a rear. However, the present invention is not limited to this, and the front left / rear right and front A diagonal split method that divides right and left rear may be adopted.
In the present embodiment, the spring-type accumulators 12f and 12r are employed. However, the present invention is not limited to this, and the brake fluid extracted from the wheel cylinders 8FL to 8RR is temporarily stored to efficiently reduce pressure. Any type such as weight type, gas compression direct pressure type, piston type, metal bellows type, diaphragm type, bladder type and in-line type may be used.

Further, in this embodiment, the pump-up type brake actuator 7 using the pump 15 is adopted. However, the present invention is not limited to this, and other pump-less brake actuators such as a volume change method equipped with a power piston can be used. A brake actuator may be employed.
In the present embodiment, the first gate valves 10f and 10r are configured to open the flow path at the non-excited normal position, and the second gate valves 14f and 14r are configured to close the flow path at the non-excited normal position. However, it is not limited to this. In short, since it is only necessary to open and close each valve, the flow path is opened at the offset position where the first gate valves 10f and 10r are excited, and the flow path is opened at the offset position where the second gate valves 14f and 14r are excited. You may comprise so that it may close.

  In the present embodiment, the front-side inlet valves 11FL and 11FR and the front-side outlet valves 13FL and 13FR are configured to close the flow path at the non-excited normal position. However, the present invention is not limited to this. Is not to be done. In short, as long as each valve can be opened and closed, the front inlet valves 11FL and 11FR and the front outlet valves 13FL and 13FR are configured to close the flow path at the excited offset position. May be.

However, in the rear wheels 1RL and 1RR, the braking force corresponding to the driver's parking brake operation must be maintained even after the ignition switch is turned off, so that the rear inlet valves 11RL and 11RR and the rear side The outlet valves 13RL and 13RR are configured to close the flow path at a non-excited normal position.
As shown in FIG. 1, the controller 6 includes wheel rotation sensors 17FL to 17RR that detect wheel speeds Vw _{FL to} Vw _RR , and a steering angle sensor 18 that detects a steering angle θ of a steering wheel (not shown). It is connected.

Next, the braking force control process executed by the controller 1 will be described based on the flowcharts of FIGS. 3 and 4.
The braking force control process is executed as a timer interruption process every predetermined time (for example, 5 msec). First, in step S1, various data (main brake operation amount S _M , parking brake operation amount S _P , wheel speeds Vw _{FL to} Vw _RR , Read the steering angle θ).

In step S2, with reference to the control map shown in FIG. 5, to calculate a target braking force F _M corresponding to the main brake operation amount S _M. The control map, the more the main brake operation amount S _M is increased, the target braking force F _M is set to increase.
In step S3, with reference to the control map shown in FIG. 6, to calculate a target braking force F _P corresponding to the parking brake operation amount S _P. The control map, the more parking brake operation amount S _P is increased, the target braking force F _P is set to increase.

In the subsequent step S4, as shown in the following equation (1), the target braking force F _B for the front wheels and the rear wheels corresponding to the driver's braking operation is calculated.
Front wheel F _B = F _M
Rear wheel F _B = F _M + F _P (1)
In a succeeding step S5, it is determined whether or not the target braking force _FP is larger than zero. When the determination result is F _P > 0, it is determined that the parking lever 3 is operated, and the process proceeds to step S7 described later. On the other hand, when the determination result is F _P = 0, it is determined that the parking lever 3 is not operated, and the process proceeds to step S6.

  In step S6, the spin turn request flag Fst indicating whether or not the driver is requesting a spin turn is reset to “0”, and then the process proceeds to step S14 in FIG. 4 to be described later. Here, the spin turn is a driving technique in which the driver intentionally slides the rear wheel (tail slide) to change the direction of the vehicle body by operating the parking brake. The spin turn request flag indicates that the driver does not request a spin turn when Fst = 0, and indicates that the driver requests a spin turn when Fst = 1.

In step S7 which shifts from the step S5, the vehicle speed V is estimated based on each wheel speed Vwi, and whether or not the vehicle speed V is equal to or less than a maximum value V _MAX (for example, 80 km / h) at which spin turn is possible. Determine. When the determination result is V ≦ V _MAX, it is determined that the vehicle is in a vehicle speed range where spin turn is possible, and the process proceeds to step S9 described later. On the other hand, when the determination result is V> V _MAX, it is determined that the spin turn cannot be performed, and the process proceeds to step S8.

In step S8, a brake warning light is displayed on the instrument panel or an alarm buzzer is activated to notify the driver that the parking brake is operating, and then the process proceeds to step S14 in FIG. To do.
In step S9, which shifts from step S7, the minimum steering angle θ _MIN necessary for performing a spin turn with respect to the vehicle speed V is calculated as shown in the following equation (2). As shown in FIG. 7, the θ _MIN is a point where the horizontal axis is the steering angle θ, the vertical axis is the vehicle speed V, V = V _MAX at θ = 360 deg, V = 0 km / h, θ = 180 deg Consists of a straight line connecting

θ _MIN = 2.25V + 180 (2)
In subsequent step S10, it is determined whether or not the steering angle θ is equal to or greater than θ _MIN . When the determination result is θ <θ _MIN, it is determined that the steering angle θ with respect to the vehicle speed V is insufficient and the spin turn cannot be performed, and the process proceeds to step S8. On the other hand, when the determination result is θ ≧ θ _MIN, it is determined that the steering angle θ with respect to the vehicle speed V is in a spin-turnable region and the driver is requesting a spin turn, and the process proceeds to step S11. That is, as shown in FIG. 7, when the vehicle speed V is high, it is determined that the driver is requesting a spin turn in a region where the steering angle θ is larger than when the vehicle speed V is low.

In step S11, a limit steering angle θ _LIM that allows grip traveling with respect to the vehicle speed V is calculated. First, the centrifugal force F _C acting on the turning vehicle is expressed by the following equation (3). Here, μ is a road surface friction coefficient, W is a vehicle weight, g is a gravitational acceleration (= 9.8 m / s ² ), and R is a turning radius. Further, (W / g) is the mass of the vehicle, and (V ² / R) is the lateral acceleration.
F _C = μ × (W / g) × (V ² / R) (3)
Moreover, the gripping force F _G with respect to the road surface is represented by the following equation (4).

F _G = μ × W (4)
The limit value at which grip travel is possible is a value such that grip force F _G = centrifugal force F _C, and is expressed by the following equation (5).
μ × W = μ × W × V ² / (g × R)
1 = V ² / (g × R)
R = V ² / g (5)
Further, there is a relationship expressed by the following equation (6) between the turning radius R and the steering angle θ. Here, K is a coefficient determined by the vehicle.

R∝K / θ (6)
Therefore, from the above formulas (5) and (6), the limit steering angle θ _{LIM at} which grip traveling can be performed with respect to the vehicle speed V is represented by the following formula (7).
K / θ _LIM = V ² / g
θ _LIM = K × g / V ² (7)
In a succeeding step S12, it is determined whether or not the steering angle θ is equal to or _larger than θ _LIM . When the determination result is θ <θ _LIM, it is determined that the vehicle speed V and the steering angle θ are in the grip travelable region and the spin turn cannot be performed, and the process proceeds to step S8. On the other hand, when the determination result is θ ≧ θ _LIM , as shown in FIG. 7, the vehicle speed V and the steering angle θ exceed the limit values for grip traveling, and the driver requests a spin turn. Determination is made and the process proceeds to step S13.

The hatched area in FIG. 7 is an area where the driver determines that a spin turn is requested in the processing of steps S10 and S12, and the other areas are areas where a spin turn cannot be made.
In step S13, the spin turn request flag Fst is reset to “1”, and then the process proceeds to step S14 in FIG.

In step S14 of FIG. 4, as shown in the following equation (8), the slip ratio λi (FL, FR, RL, RR) of each wheel is calculated.
λi = (V−Vwi) / V (8)
In step S15, it determines whether or not the slip ratio λi of each wheel exceeds a predetermined value lambda _opt individually. The predetermined value λ _opt is a value in the vicinity of the slip ratio when the braking friction coefficient μ _B is maximum, and is a value that can shorten the braking distance as much as possible while ensuring the steering performance. Here, when the determination result is λi> _λopt, it is determined that the wheel tends to be locked, and the process proceeds to step S18 described later. On the other hand, when the determination result is λi ≦ _λopt, it is determined that the wheel does not tend to lock, and the process proceeds to step S16.

In step S16, as shown in the following equation (9), the target braking force F _B i calculated in step S4 is set as the braking force command value F _T i.
F _T i = F _B i (9)
In step S17, to return the braking force command value F _T from the output to the brake actuator 7 to the predetermined main program.

In step S18 which moves from step S15, it is determined whether or not the spin turn request flag Fst is set to “1”. When the determination result is Fst = 1, the process proceeds to step S21 described later. On the other hand, when the determination result is Fst = 0, the process proceeds to step S19.
In step S19, until the slip ratio λi reaches the normal target slip ratio λ ^* (for example, about 10% to 20%), the slip ratio λi is set to the normal target change amount every calculation cycle (5 msec in this embodiment). The target braking force F _ABS i of each wheel for increasing by Δλ _N , that is, for increasing the slip rate _λ i at the target change rate is calculated individually.

In step S20, as shown in the following equation (10), the select low between the target braking force F _ABS i by the target braking force F _B i and anti-skid control in accordance with the brake operation, the braking force command value F _T After the calculation, the process proceeds to step S20.
F _T = min [F _B i, F _ABS i] (10)
In step S21, which shifts from step S18, a correction map λ _R of the target slip ratio λ ^* is calculated according to the steering angle θ with reference to a control map as shown in FIG. This control map is set so that the correction amount λ _R increases as the steering angle θ increases.

In step S22, as shown in the following equation (11), by adding the correction amount lambda _R to the target slip ratio lambda ^*, corrects the target slip ratio lambda ^*.
λ ^* ← λ ^* + λ _R ……… (11)
In the subsequent step S23, the steering angular velocity θ ′ is calculated from the steering angle θ, and the target change amount Δλ of the slip ratio λ for each calculation cycle is calculated from the steering angular velocity θ ′ by referring to a control map as shown in FIG. To do. This control map is set so that the target change amount Δλ becomes larger as the steering angular velocity θ ′ is faster from a value larger than the above-described normal target change amount Δλ _N.

In the subsequent step S24, as shown in FIG. 10, until the slip rate λi reaches the target slip rate λ ^* , the slip rate λi is increased by the target change amount Δλ every calculation cycle, that is, the slip rate λi is increased by the target change rate. in the braking force command value F _T i of each wheel to increase calculated separately, to return from the transition to the predetermined main program to the step S20.
As described above, the processes of steps S14, S15, S19, and S20 correspond to the “lock tendency suppression unit”, the processes of steps S5 to S13 correspond to the “spin turn request determination unit”, and the processes of steps S18 and S21 to S24. Corresponds to “restriction means”. Further, the operation of the parking lever 3 corresponds to the “parking brake operation”, the steering angle θ corresponds to the “turning operation amount”, the steering angular velocity θ ′ corresponds to the “increase speed of the turning operation amount”, and the slip ratio λ Corresponds to the “slip state”, the target slip rate λ ^* corresponds to the “target slip state”, and the target change amount Δλ for each calculation cycle corresponds to the “target change rate”.

Next, the operation and effects of the one embodiment will be described.
When the driver operates the brake pedal 2 and the parking lever 3, the brake-by-wire braking force of each wheel is controlled in accordance with the main brake operation amount S _M and the parking brake operation amount S _P. At this time, if a wheel locking tendency due to braking is detected ("Yes" in step S15), a target braking force F _ABS i sufficiently suppressed to achieve the normal target slip ratio λ ^* is calculated ( In step S19), the braking force command value F _T i is reduced by a select low between the target braking force F _ABS i and the target braking force F _B i corresponding to the brake operation. By such anti-skid control, the braking force is suppressed and the tendency of the wheels to lock can be reliably prevented.

By the way, regardless of whether the operation is a main brake operation or a parking brake operation, if such anti-skid control is performed, even if the driver intentionally performs a spin turn and operates the parking lever 3, As shown in FIG. 11, the braking force command value F _T i is suppressed by the operation of the anti-skid control, and the slip ratio λi is controlled to the target slip ratio λ ^* , thereby preventing the wheels from being locked and I can't make the spin turn I want.

Therefore, it is determined whether or not the driver is requesting a spin turn with a parking brake operation (steps S5 to S13), and if it is determined that the driver is requesting a spin turn (the determination in step S18 is “Yes”). "), The suppression of the braking force by the anti-skid control is limited (steps S21 to S24).
As a result, when the driver tries to perform a spin turn by the parking brake operation, the slip rate λi can be increased and the wheel can be locked, so that the spin turn desired by the driver can be realized. . In addition, when the driver is trying to perform normal grip driving, that is, when the driver does not request a spin turn (the determination in step S18 is “No”), if a wheel locking tendency is detected, it is parked. Even in the case of a brake operation, safety can be ensured by executing normal anti-skid control to suppress the braking force (steps S19 and S20) and reliably preventing the wheels from being locked.

  Whether or not the driver is requesting a spin turn depends on whether or not the vehicle speed V and the steering angle θ are in the hatched region of FIG. 7 when the driver operates the parking lever 3. to decide. When the driver makes a spin turn, it is necessary to perform not only the parking brake operation but also a large steering operation. Therefore, the driver requests a spin turn based on at least the steering angle θ that is the turning operation of the driver. By determining whether or not, it can be determined reliably.

Specifically, first, the minimum steering angle θ _MIN necessary for performing a spin turn is calculated for the vehicle speed V (step S9), and it is determined whether or not the steering angle θ is equal to or greater than θ _MIN ( Step S10). In this determination process, as shown in FIG. 7, when the vehicle speed V is high, it is determined that the driver is requesting a spin turn in a region where the steering angle θ is larger than when the vehicle speed V is low. This is because as the vehicle speed V increases, yaw rate is less likely to occur and the spin turn becomes more difficult unless the steering angle θ is large. Therefore, it can be accurately determined from the vehicle speed V and the steering angle θ whether or not the driver is requesting a spin turn.

Subsequently, a limit steering angle θ _LIM that allows grip traveling with respect to the vehicle speed V is calculated (step S11), and it is determined whether or not the steering angle θ is equal to or _larger than θ _LIM (step S12). In this determination process, as shown in FIG. 7, it is determined that the driver is requesting a spin turn in a region where the vehicle speed V and the steering angle θ exceed the limit values at which grip traveling is possible. This is because the spin turn intentionally generates a centrifugal force F _C that exceeds the grip force F _G and causes the rear wheels to slide sideways. Therefore, it can be accurately determined from the vehicle speed V and the steering angle θ whether or not the driver is requesting a spin turn.

On the other hand, when the steering angle θ is less than θ _MIN (determination in step S10 is “No”) or when the steering angle θ is less than θ _LIM (determination in step S12 is “No”), the driver makes a spin turn. Is not requested, or it is not in a state where a spin turn is possible. As a result, for example, it is possible to prevent the anti-skid control from being restricted due to forgetting to release the parking brake or due to a simple operation error. At this time, a brake warning light is displayed on the instrument panel or an alarm buzzer is operated to notify the driver that the parking brake is operating (step S8), thereby releasing the parking brake. It is possible to prompt or to recognize an operation mistake.

If it is determined that the driver is requesting a spin turn, the target slip ratio λ ^* is increased by adding the correction amount λ _R (step S22). According to this, as shown in FIG. 12, the slip ratio λi is increased to allow the rear wheel to be locked, that is, the rear wheel can be reliably locked by restricting the suppression of the braking force by the anti-skid control. Therefore, the spin turn that the driver wants can be realized.

Here, the correction amount λ _R is calculated so as to increase as the steering angle θ increases (step S21). Therefore, as the steering angle θ increases, the limit amount for the braking force suppression by the anti-skid control increases. Become. This is because, if the correction amount λ _R is made constant regardless of the steering angle θ, the slip ratio λ i of the wheel becomes constant no matter how much the driver performs the steering operation. Accordingly, by increasing the correction amount λ _R and locking the wheel as the steering angle θ increases, the driver can control the vehicle behavior when performing a spin turn in accordance with the steering angle θ.

Further, if it is determined that the driver is requesting a spin turn, the target amount of change of the slip rate .lambda.i at each calculation cycle, is increased from a normal [Delta] [lambda] _N to [Delta] [lambda], i.e. to increase the rate of change of the slip rate .lambda.i ( Step S23). According to this, the speed of increase of the slip rate λi can be increased to promote the tendency of the rear wheels to lock, that is, the braking of the braking force by the anti-skid control can be quickly restricted and the rear wheels can be locked. You can achieve the spin turn you want.

  Here, the target change amount Δλ is calculated so as to increase as the steering angular velocity θ ′ increases (step S23). Therefore, as the steering angular velocity θ ′ increases, the limit amount for suppressing the braking force by the anti-skid control. Becomes larger. This is because if the target change amount Δλ is made constant regardless of the steering angular velocity θ ′, the increase rate of the slip ratio λi becomes constant no matter how fast the driver performs the steering operation. Therefore, as the steering angular velocity θ ′ increases, the target change amount Δλ is increased and the rear wheel is quickly locked, so that the driver can control the vehicle behavior during the spin turn according to the steering angular velocity θ ′. Is possible.

In the above-described embodiment, the parking brake is configured by a lever system, but is not limited thereto, and may be configured by a stepping system.
The switch in one embodiment of the above, in the processing in step S3, it calculates the target braking force F _P corresponding to the parking brake operation amount S _P, it is not limited thereto, the parking brake operation in is detected, When the switch is turned oN, the predetermined value to the target braking force F _P (e.g., 18.4KN) may be set to.

Further, in one embodiment described above, in the processing of step S4, the target braking force F _B of the rear wheels, the target braking force F _M corresponding to the main brake operation amount S _M, according to the parking brake operation amount S _P The calculation is performed by adding the target braking force F _P. However, the present invention is not limited to this, and a select high of F _M and F _P may be used.
Furthermore, in one embodiment described above, in the processing of step S2, S4, although the same value at front and rear wheel target braking force F _M corresponding to the main brake operation amount S _M, it is not limited thereto , it may be value in accordance with the target braking force F _M of the front and rear wheels to the ideal braking force distribution curve.

  In the above embodiment, the driver requests a spin turn by determining whether or not the steering angle θ is within a predetermined range with respect to the vehicle speed V in the processes of steps S9 to S12. Although it is determined whether or not, it is not limited to this. In short, since it is only necessary to determine whether or not the relationship between the vehicle speed V and the steering angle θ is in a predetermined state, the equations (2) and (7) are converted into equations for the vehicle speed V, and the steering angle θ On the other hand, it may be determined whether the driver is requesting a spin turn by determining whether the vehicle speed V is in a predetermined region.

In the above-described embodiment, whether or not the driver requests a spin turn is determined according to the steering angle θ, but the present invention is not limited to this. In short, since it is only necessary to be able to make a determination according to the turning operation of the driver, the determination may be made according to the operation speed, that is, the steering angular velocity θ ′.
In the above-described embodiment, whether or not the driver requests a spin turn is determined according to the turning operation of the driver. However, the present invention is not limited to this, and lateral acceleration and yaw rate are not limited thereto. Alternatively, the determination may be made according to the amount of turning state of the vehicle such as the difference between the left and right wheel speeds. Furthermore, since it may be determined according to the turning state of the vehicle, the determination may be performed according to the changing speed such as the lateral acceleration, the yaw rate, and the left / right wheel speed difference.

In the above-described embodiment, the so-called 4-sensor 4-channel type anti-skid control for detecting the wheel speeds Vw _{FL to} Vw _RR and controlling the hydraulic pressures of the wheel cylinders 8FL to 8RR is performed. It is not limited to this. That is, an arbitrary system such as a 4-sensor 3-channel system or a 3-sensor 3-channel system may be employed.
In the above embodiment, the anti-skid control is performed using only the slip ratio λ as a control parameter. However, the present invention is not limited to this. The speed and wheel acceleration may be used as control parameters, or the wheel deceleration, wheel acceleration, and slip ratio λ may be used as control parameters.

Further, in the above-described embodiment, when it is determined that the driver requests a spin turn, the operation is limited, that is, the slip ratio λi is increased while the anti-skid control is activated. However, the operation may be limited by stopping the operation of the anti-skid control when it is determined that the driver requests a spin turn.
In the above-described embodiment, the correction amount λ _R of the target slip ratio λ ^* is calculated according to the steering angle θ in the process of step S21. However, the present invention is not limited to this. In short, it is only necessary to be able to calculate according to the turning operation of the driver or the turning state of the vehicle, so the calculation may be made according to the steering angular velocity θ ′, the lateral acceleration, the yaw rate, the left / right wheel speed difference, or the like.

In the above-described embodiment, the target change amount Δλ of the target slip ratio λ ^* is calculated according to the steering angular velocity θ ′ in the process of step S23. However, the present invention is not limited to this. In short, since it is only necessary to be able to calculate according to the driver's turning operation or the turning state of the vehicle, it may be calculated according to the steering angle θ, the lateral acceleration, the yaw rate, the left / right wheel speed difference, or the like.
In the above embodiment, the brake actuator 7 supplies hydraulic pressure to the wheel cylinders 8FL to 8RR to generate the braking force. However, the present invention is not limited to this. For example, an electric brake that drives and controls the electric actuator and clamps the disk rotor with a brake pad or presses a brake shoe against the inner peripheral surface of the brake drum, a regenerative brake, or the like may be used.

  In the above embodiment, the braking force according to the driver's main brake operation and the braking force according to the parking brake operation are generated by the common wheel cylinder. However, the present invention is not limited to this. is not. In other words, a conventional hydraulic brake mechanism that mechanically generates a braking force in conjunction with the driver's main brake operation and a parking brake mechanism that can control the braking force according to the driver's parking brake operation are individually provided. It may be provided. In this case, if the anti-skid control detects the locking tendency of the rear wheel to which the braking force according to the driver's parking brake operation is applied and suppresses the braking force generated by the parking brake mechanism, the present invention Can be applied. That is, when it is determined that the driver is requesting a spin turn, when the anti-skid control tries to suppress the braking force generated by the parking brake mechanism, the suppression of the braking force is limited. An effect is obtained.

  In the above embodiment, the braking force by the driver's parking brake operation is applied only to the rear wheels. However, the present invention is not limited to this, and the braking force may be applied to all the front and rear wheels. However, in this case, the effect of the present invention can be obtained by limiting the anti-skid control only to the rear wheels. That is, if it is determined that the driver is requesting a spin turn, when the anti-skid control tries to suppress the braking force of the front and rear wheels, by limiting the suppression of the braking force of only the rear wheels, Can be reliably locked, so that the effect of the present invention can be obtained.

  Furthermore, in the above-described embodiment, the brake-by-wire capable of controlling the braking force according to the driver's parking brake operation is employed. However, the present invention is not limited to this, and is interlocked with the driver's parking brake operation. A conventional wire type or linkage type parking brake mechanism that mechanically generates a braking force may be employed. However, in this case, a device that can control the driving force of the rear wheel provided with the parking brake mechanism separately from the driving force of the front wheel is provided, and the driving force of the rear wheel is increased when the rear wheel lock tendency is detected. Thus, the present invention can be applied as long as it has a system (locking tendency suppressing means) for suppressing the locking tendency. That is, when it is determined that the driver is requesting a spin turn, when the lock tendency suppression means tries to cancel the lock tendency by offsetting the braking force generated by the parking brake mechanism by increasing the driving force, The effect of the present invention can be obtained by limiting the increase in the driving force. Incidentally, as a device that can control the driving force of the rear wheels separately from the driving force of the front wheels, for example, a conventional rear wheel driving vehicle, or a so-called motor 4WD that drives one of the front and rear wheels by an engine and the other by a motor. And a parallel hybrid system that drives the rear wheels with an engine and a motor.

  Furthermore, in the above embodiment, the present invention is applied to a four-wheel vehicle, but may be applied to a two-wheel vehicle, a three-wheel vehicle, or a vehicle having five or more wheels.

It is a schematic structure figure showing an embodiment of the present invention. It is a hydraulic circuit of a brake actuator. It is a flowchart which shows a braking force control process (first half). It is a flowchart which shows a braking force control process (second half). It is a control map used for calculating the target braking force F _M. It is a control map used for calculating the target braking force F _P. It is a graph which shows the relationship between the vehicle speed V at the time of a spin turn request | requirement, and steering angle (theta). It is a control map used for calculation of the correction amount λ _R. It is a control map used for calculation of the target change amount Δλ. It is a time chart which shows the change rate of slip ratio (lambda). It is a time chart explaining a prior art. It is a time chart explaining the effect of the present invention.

Explanation of symbols

1FL to 1RR Wheel 2 Brake pedal 3 Parking lever 4, 5 Stroke sensor 6 Controller 7 Brake actuator 8FL to 8RR Wheel cylinder 9 Reservoir tank 10f and 10r First gate valve 11FL to 11RR Inlet valve 12f and 12r Accumulator 13FL to 13RR Outlet valve 14f 14r 2nd gate valve 15 Pump 16 Damper chamber 17FL-17RR Wheel rotation sensor 18 Rudder angle sensor

Claims (9)

  Determines whether the driver is requesting a lock tendency suppression means for suppressing the tendency of the wheel to lock against a wheel to which braking force is applied by the driver's parking brake operation, and a spin turn accompanied by the parking brake operation. A spin turn request determining means, and when the spin turn request determining means determines that the driver is requesting a spin turn, a limiting means for limiting the suppression of the wheel lock tendency by the lock tendency suppressing means, A vehicular braking control apparatus comprising:   The spin turn request determination means determines whether the driver is requesting a spin turn based on at least one of a turning operation by the driver and a turning state of the vehicle when the driver is operating a parking brake. The vehicular braking control apparatus according to claim 1, wherein:   The spin turn request determination means determines that the driver is requesting a spin turn when the vehicle speed is high in a region where the amount of turning operation or the amount of turning state is larger than when the vehicle speed is low. Item 3. The vehicle brake control device according to Item 2.   The spin turn request determining means determines that the driver is requesting a spin turn in a region where the vehicle speed and the turning operation amount or the turning state amount exceed a limit value where grip driving is possible. The vehicle braking control device according to claim 2 or 3.   The restricting means, when the spin turn request determining means determines that the driver is requesting a spin turn, the larger the turning operation amount or the turning state quantity, the more the wheel lock tendency by the lock tendency suppressing means. The vehicular braking control apparatus according to any one of claims 1 to 4, wherein a restriction amount for suppression is increased.   When the spin turn request determination means determines that the driver is requesting a spin turn, the limiting means increases the turning tendency as the turning operation amount or the turning state quantity increases faster. The vehicular braking control apparatus according to any one of claims 1 to 5, wherein a limit amount for suppressing a wheel lock tendency by the suppressing means is increased. The lock tendency suppression means suppresses the wheel lock tendency by controlling the braking / driving force so that the slip state of the wheel becomes the target slip state,
The vehicular braking according to any one of claims 1 to 6, wherein the limiting means limits the suppression of wheel lock tendency by the lock tendency suppressing means by increasing the target slip state. Control device. The lock tendency suppression means suppresses the wheel lock tendency by controlling the braking / driving force so that the slip state of the wheel reaches the target slip state at a target change rate,
8. The vehicle brake control apparatus according to claim 7, wherein the limiting unit limits the suppression of wheel lock tendency by the lock tendency suppression unit by increasing the target change rate.   The vehicle for a vehicle according to any one of claims 1 to 8, wherein the restricting means restricts the restraint of the wheel lock tendency by the lock tendency restraining means only to the rear wheels. Braking control device.

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