JP3731290B2 - Vehicle behavior control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a behavior control apparatus that suppresses and reduces drift-out during turning of a vehicle such as an automobile.
[0002]
[Prior art]
As one of devices for controlling the behavior of a vehicle such as an automobile when turning, a drift-out state indicating the turning behavior of the vehicle as described in, for example, Japanese Patent Application Laid-Open No. 8-85430 according to the application of the present applicant. The behavior estimation means for estimating the drift-out state based on the amount, and when the drift-out state is estimated, the turning behavior is controlled by applying a braking force to a predetermined wheel according to the drift-out state amount and suppressing the drift-out. A vehicle behavior control device having behavior control means, wherein the vehicle situation control means determines whether or not the vehicle is in a predetermined driving situation in which spin is induced by control by the behavior control means, based on a parameter indicating the driving situation of the vehicle. And a means for reducing the control amount of the behavior control means when it is determined that the vehicle is in a predetermined traveling state. Vehicle behavior control device are already known.
[0003]
According to such a behavior control device, it is determined whether or not a predetermined driving situation in which spin is induced by control by the behavior control means from a parameter indicating the driving condition of the vehicle, and it is determined that the driving condition is the predetermined driving condition. Sometimes the control amount of the behavior control means is reduced, so that the drift-out suppression control amount is reduced or the drift-out suppression is prohibited, so that the spin is prevented from being induced by the drift-out suppression control by the behavior control means. be able to.
[0004]
[Problems to be solved by the invention]
In the behavior control device according to the above-mentioned proposal, the determination as to whether or not the vehicle is in a predetermined driving situation in which spin is induced is made based on the slip angle of the rear wheel. In the situation where the vehicle is in the drift-out state, the estimation accuracy of the slip angle of the rear wheel is low. For example, the drift-out state continues for a relatively long time and the drift-out suppression control is performed for a relatively long time. In the case of slow spinning, it is difficult to accurately determine whether or not the driving situation is the one in which spin is induced, and in such a situation, the vehicle will be in the spinning state. Is difficult to prevent.
[0005]
The present invention has been made in view of the above-mentioned problems in the conventional behavior control apparatus, and the main problem of the present invention is that the drift-out suppression control is performed for a relatively long time with a relatively high control amount. By preventing this, even when the drift-out state continues for a relatively long time, it is possible to reliably prevent the vehicle from entering the spin state due to the drift-out suppression control.
[0006]
[Means for Solving the Problems]
  According to the present invention, the main problem described above is the configuration of claim 1, that is, means for estimating a drift-out state quantity of a vehicle, and at least the drift-out when the drift-out state quantity exceeds a reference value. Calculation means for calculating a drift-out suppression control amount based on the state quantity, and reducing the drift-out state by decelerating the vehicle or applying a turning assist yaw moment to the vehicle based on the drift-out suppression control quantityPerform drift-out suppression controlIn a vehicle behavior control device having a control means,By obtaining a correction amount that gradually increases in magnitude by low-pass filtering the drift-out suppression control amount,Correction means for correcting the drift-out suppression control amount by subtracting a correction amount that gradually increases in magnitude from the drift-out suppression control amount is provided.The control means performs the drift-out suppression control based on the corrected drift-out suppression control amount.Vehicle behavior control deviceOr the configuration of claim 2, that is, the means for estimating the drift-out state quantity of the vehicle and the drift-out suppression control quantity based on at least the drift-out state quantity when the drift-out state quantity exceeds the reference value A vehicle behavior control device comprising: a calculating means for performing a drift-out suppression control for decelerating the vehicle based on the drift-out suppression control amount or applying a turning assist yaw moment to the vehicle to reduce a drift-out state. In this case, a correction amount that gradually increases in magnitude is obtained by subjecting the drift-out suppression control amount to a gradient limiting process, and a correction amount that gradually increases in magnitude is subtracted from the drift-out suppression control amount. And a correction unit that corrects the drift-out suppression control amount. A vehicle behavior control device that performs the drift-out suppression control based on an out-control amount, or a configuration of claim 3, that is, a means for estimating a drift-out state amount of a vehicle, and the drift-out state amount When the reference value is exceeded, calculation means for calculating a drift-out suppression control amount based on at least the drift-out state amount, and decelerating the vehicle based on the drift-out suppression control amount or applying a turning assist yaw moment to the vehicle In a vehicle behavior control device having control means for performing drift-out suppression control for reducing a drift-out state, the drift-out is obtained by subtracting a correction amount whose size gradually increases from the drift-out suppression control amount. A correction means for correcting the suppression control amount, wherein the control means is a drift drift after correction. The drift correction control amount is controlled based on the drift suppression control amount when the sign of the drift out suppression control amount before correction and the drift out suppression control amount after correction is different from each other. The vehicle behavior control device characterized in that the vehicle behavior control device is set to 0, or the configuration of claim 4, that is, the means for estimating the drift-out state quantity of the vehicle, and at least when the drift-out state quantity exceeds the reference value Calculation means for calculating a drift-out suppression control amount based on the drift-out state amount, and drift-out suppression for reducing the drift-out state by decelerating the vehicle or applying a turning assist yaw moment to the vehicle based on the drift-out suppression control amount In a vehicle behavior control device having control means for controlling Compensating means for correcting the drift-out suppression control amount by subtracting an increasing correction amount from the drift-out suppression control amount, and the control means controls the drift-out suppression control based on the corrected drift-out suppression control amount. And the correction means determines the turning direction, and sets the correction amount to 0 when the turning direction is reversed.Achieved by:
[0007]
  According to the configuration of claim 1, the drift-out suppression control amountA low-pass filter processing is performed to obtain a correction amount that gradually increases in size,The amount of correction that gradually increases in size isFrom drift-out suppression control amountBy subtracting, the drift-out suppression control amount is corrected. Based on the corrected drift-out suppression control amount, the vehicle is decelerated or a turning assist yaw moment is applied to the vehicle, so that the drift-out state continues for a relatively long time. Even when the drift-out suppression control is performed for a relatively long time, the drift-out suppression control is prevented from being performed for a relatively long time with a relatively high control amount, which causes the vehicle to slowly move due to the drift-out suppression control. A spin state is reliably prevented.
  According to the second aspect of the present invention, a correction amount that gradually increases in magnitude can be obtained by subjecting the drift-out suppression control amount to the gradient limiting process, and the correction amount that gradually increases in magnitude is the drift-out suppression control amount. By subtracting more, the drift-out suppression control amount is corrected, and the vehicle is decelerated based on the corrected drift-out suppression control amount or a turning assist yaw moment is applied to the vehicle. It is possible to prevent the out suppression control from being performed for a relatively long time with a relatively high control amount, thereby reliably preventing the vehicle from slowly entering the spin state due to the drift out suppression control.
  According to the third aspect of the invention, when the sign of the drift-out suppression control amount before correction and the drift-out suppression control amount after correction are different from each other, the corrected drift-out suppression control amount is set to 0. The drift-out suppression control is appropriately performed because the control that decelerates the vehicle or applies the turning assist yaw moment to the vehicle to reduce the drift-out state is performed based on an inappropriate corrected drift-out suppression control amount. It is reliably prevented that it is not performed.
  According to the fourth aspect of the present invention, the correction means determines the turning direction, and sets the correction amount to 0 when the turning direction is reversed. Therefore, the drift-out suppression control amount can be corrected with an inappropriate correction amount. It is reliably prevented that the drift-out suppression control is performed with an inappropriate control amount immediately after the turning direction is reversed.
[0008]
  According to the present invention, in order to effectively achieve the above-mentioned problems,Thru 4The control means gives a turning assist yaw moment to the vehicle while decelerating the vehicle by braking at least the left and right rear wheels, and the correction meansWithout correcting the control amount other than the rear wheels on the inside of the turnIt is configured to correct only the control amount of the turning inner rear wheel.5Configuration).
[0009]
Generally, when the vehicle turns, the ground contact load of the turning inner wheel decreases due to load movement, and in particular, drift-out suppression control is performed by braking the left and right rear wheels to decelerate the vehicle and giving the vehicle a turning assist yaw moment. In this case, the braking force of the rear wheel on the inside of the turn is excessive, and the lateral force of the wheel is insufficient, which causes the vehicle to easily enter a spin state.
[0010]
  Claim5With this configuration, the vehicle is decelerated by braking at least the left and right rear wheels, and a turning assist yaw moment is given to the vehicle.Control amount other than the rear inner wheel is not correctedSince only the control amount of the turning inner rear wheel is corrected, it is prevented that the braking force of the turning inner rear wheel becomes excessive and the lateral force is insufficient.Other than turning inner rear wheelSince the control amount of the wheel is not corrected, it is possible to prevent the vehicle from decelerating and the turning assist yaw moment from being excessively insufficient.
[0015]
[Preferred embodiment of the problem solving means]
  The present inventionOneAccording to one preferred embodiment, the above-mentioned claim1 to 5In this configuration, the means for estimating the vehicle spin state amount, the means for estimating the vehicle drift-out state amount, the target yaw moment control amount and the target deceleration control amount based on the spin state amount and the drift-out state amount are calculated. And a means for calculating a control amount for each wheel based on the target yaw moment control amount and the target deceleration control amount (preferred embodiment).1).
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0017]
FIG. 1 is a schematic configuration diagram showing a hydraulic circuit and an electric control device of one embodiment of a behavior control device according to the present invention.
[0018]
In FIG. 1, a braking device 10 corresponds to a master cylinder 14 that pumps brake oil from first and second ports in response to a driver's depressing operation of a brake pedal 12, and an oil pressure in the master cylinder. And a hydro booster 16 for increasing the brake oil to the pressure (regulator pressure). The first port of the master cylinder 14 is connected to the brake hydraulic control devices 20 and 22 for the left and right front wheels by the brake hydraulic control conduit 18 for the front wheels, and the second port is a brake for the rear wheels having a proportional valve 24 on the way. The hydraulic control conduit 26 is connected to a three-port two-position switching electromagnetic control valve 28 for left and right rear wheels. The control valve 28 is connected by a conduit 30 to a brake hydraulic pressure control device 32 for the left rear wheel and a brake hydraulic pressure control device 34 for the right rear wheel.
[0019]
The braking device 10 also has an oil pump 40 that pumps up the brake oil stored in the reservoir 36 and supplies it to the high-pressure conduit 38 as high-pressure oil. The high-pressure conduit 38 is connected to the hydro booster 16 and is also connected to a front-wheel switching valve 42 and a rear-wheel switching valve 44, and high-pressure oil discharged from the oil pump 40 in the middle of the high-pressure conduit 38. Is connected to the accumulator 46. As shown in the figure, the switching valves 42 and 44 are also 3-port 2-position switching electromagnetic switching valves.
[0020]
The brake hydraulic control devices 20 and 22 for the left and right front wheels are connected to wheel cylinders 48FL and 48FR for controlling braking force for the corresponding wheels, three-port two-position switching electromagnetic control valves 50FL and 50FR, and a reservoir 36, respectively. Normally-open electromagnetic on-off valves 54FL and 54FR and a normally-closed type provided in the middle of the regulator pressure supply conduit 53 connected between the low-pressure conduit 52 serving as the return passage and the discharge port of the hydro booster 16 The electromagnetic on-off valves 56FL and 56FR are provided. Regulator pressure supply conduits 53 between the on-off valves 54FL and 54FR and the on-off valves 56FL and 56FR are connected to the control valves 50FL and 50FR by connection conduits 58FL and 58FR, respectively.
[0021]
The brake hydraulic pressure control devices 32 and 34 for the left and right rear wheels are normally open electromagnetic on-off valves 60RL and 60RR provided in the middle of the conduit 30 between the control valve 28 and the low pressure conduit 52, and a normally closed type. Electromagnetic on-off valves 62RL and 62RR and wheel cylinders 64RL and 64RR for controlling the braking force for the corresponding wheels are provided. The wheel cylinders 64RL and 64RR are opened and closed with the on-off valves 60RL and 60RR by connecting pipes 66RL and 66RR, respectively. It is connected to the conduit 30 between the valves 62RL and 62RR.
[0022]
The control valves 50FL and 50FR respectively connect the brake hydraulic control conduit 18 for the front wheels and the wheel cylinders 48FL and 48FR in communication with each other and block the communication between the wheel cylinders 48FL and 48FR and the connection conduits 58FL and 58FR in the illustrated first position. The brake hydraulic control conduit 18 is switched to the second position where the communication between the wheel cylinders 48FL and 48FR is cut off and the wheel cylinders 48FL and 48FR are connected to the connection conduits 58FL and 58FR.
[0023]
A regulator pressure supply conduit 68 for the left and right rear wheels is connected between the regulator pressure supply conduit 53 and the left and right rear wheel control valve 28. The control valve 28 opens and closes with the brake hydraulic pressure control conduit 26 for the rear wheel, respectively. The first position shown in the figure, which connects the valves 60RL and 60RR in communication and cuts off the communication between the on-off valves 60RL and 60RR and the regulator pressure supply conduit 68, and the communication between the brake hydraulic control conduit 26 and the on-off valves 60RL and 60RR. The switch is switched to the second position where the on / off valves 60RL and 60RR and the regulator pressure supply conduit 68 are connected in communication.
[0024]
The control valves 50FL, 50FR, 28 function as master cylinder pressure cutoff valves. When these control valves are in the first position shown in the figure, the wheel cylinders 48FL, 48FR, 64RL, 64RR are connected to the conduits 18, 26, When the master cylinder pressure is supplied to each wheel cylinder, the braking force of each wheel is controlled according to the depression amount of the brake pedal 12 by the driver, and when the control valves 50FL, 50FR, 28 are in the second position. Each wheel cylinder is shut off by the master cylinder pressure.
[0025]
The switching valves 42 and 44 function to switch the hydraulic pressure supplied to the wheel cylinders 48FL, 48FR, 64RL and 64RR between the accumulator pressure and the regulator pressure, and the control valves 50FL, 50FR and 28 are in the second position. When the switching valves 42 and 44 are maintained at the first position shown in the figure with the on-off valves 54FL, 54FR, 60RL, 60RR and the on-off valves 56FL, 56FR, 62RL, 62RR being in the illustrated positions, The regulator pressure is supplied to the wheel cylinders 48FL, 48FR, 64RL, and 64RR, whereby the pressure in each wheel cylinder is controlled by the regulator pressure, thereby regardless of the depression amount of the brake pedal 12 and the braking pressure of other wheels. The braking pressure of the wheel is controlled in the pressure increasing mode by the regulator pressure.
[0026]
Even if each valve is set to be switched to the regulator pressure increasing mode, if the pressure in the wheel cylinder is higher than the regulator pressure, the oil in the wheel cylinder will flow backward, even though the control mode is in the pressure increasing mode. The actual braking pressure will decrease.
[0027]
The control valves 50FL, 50FR, 28 are switched to the second position, and the switching valves 42, 44 in a state where the on-off valves 54FL, 54FR, 60RL, 60RR and the on-off valves 56FL, 56FR, 62RL, 62RR are at the illustrated positions. Is switched to the second position, the accumulator pressure is supplied to the wheel cylinders 48FL, 48FR, 64RL and 64RR, so that the pressure in each wheel cylinder is controlled by the accumulator pressure higher than the regulator pressure. Regardless of the depression amount of the pedal 12 and the braking pressure of other wheels, the braking pressure of the wheels is controlled in the pressure increasing mode by the accumulator pressure.
[0028]
Further, the open / close valves 54FL, 54FR, 60RL, and 60RR are switched to the second position while the control valves 50FL, 50FR, and 28 are switched to the second position, and the open / close valves 56FL, 56FR, 62RL, and 62RR are illustrated. When controlled to the state, the pressure in each wheel cylinder is maintained regardless of the position of the switching valves 42 and 44, and the control valves 50FL, 50FR, 28 are switched to the second position and the on-off valves 54FL, When the 54FR, 60RL, 60RR and the on-off valves 56FL, 56FR, 62RL, 62RR are switched to the second position, the pressure in each wheel cylinder is reduced regardless of the positions of the switching valves 42 and 44, thereby the brake pedal 12 Regardless of the amount of stepping on and the braking pressure of other wheels, the braking pressure of the wheels is controlled in the pressure reduction mode.
[0029]
The switching valves 42 and 44, the control valves 50FL, 50FR, 28, the on-off valves 54FL, 54FR, 60RL, 60RR and the on-off valves 56FL, 56FR, 62RL, 62RR are controlled by the electric control device 70 as will be described in detail later. . The electric control device 70 includes a microcomputer 72 and a drive circuit 74. The microcomputer 72 is not shown in detail in FIG. 1, but for example, a central processing unit (CPU), a read only memory (ROM), and the like. It may have a general configuration including a random access memory (RAM) and an input / output port device, which are connected to each other by a bidirectional common bus.
[0030]
A signal indicating the vehicle speed V from the vehicle speed sensor 76, a signal indicating the lateral acceleration Gy of the vehicle body from the lateral acceleration sensor 78 provided substantially at the center of gravity of the vehicle body, and a vehicle body velocity from the yaw rate sensor 80 are input to the input / output port device of the microcomputer 72. A signal indicating the yaw rate γ, a signal indicating the steering angle θ from the steering angle sensor 82, a signal indicating the longitudinal acceleration Gx of the vehicle body from the longitudinal acceleration sensor 84 provided substantially at the center of gravity of the vehicle body, and the wheel speed sensors 86FL to 86RR, respectively. Signals indicating wheel speeds (circumferential speeds) Vwi (i = fl, fr, rl, rr) of the left and right front wheels and the left and right rear wheels are input. The lateral acceleration sensor 78, the yaw rate sensor 80, and the like detect lateral acceleration and the like with the left turning direction of the vehicle as positive, and the longitudinal acceleration sensor 84 detects longitudinal acceleration with the acceleration direction of the vehicle as positive.
[0031]
The ROM of the microcomputer 72 stores various control flows and maps as described later, and the CPU performs various calculations as described later based on the parameters detected by the various sensors described above to determine the turning behavior of the vehicle. While determining, the target braking force of each wheel for stabilizing the turning behavior of the vehicle is calculated, and the braking force of each wheel is controlled based on the calculation result.
[0032]
Next, an overview of vehicle behavior control will be described with reference to the general flowchart shown in FIG. The control according to the flowchart shown in FIG. 2 is started by closing an ignition switch not shown in the figure, and is repeatedly executed at predetermined time intervals.
[0033]
First, in step 50, a signal indicating the vehicle speed V detected by the vehicle speed sensor 76 is read, and in step 100, a spin state quantity indicating the degree of spin of the vehicle according to the flowchart shown in FIG. SS is calculated, and in step 150, a drift-out state quantity DS indicating the degree of drift-out of the vehicle is calculated in accordance with the flowchart shown in FIG.
[0034]
In step 200, the total yaw moment control amount Mt and the total deceleration control amount Gt are calculated according to the flowchart shown in FIG. 5, and in step 250, the target yaw moment control is performed according to the flowchart shown in FIG. The amount Mreq is calculated, and in step 300, the target deceleration control amount Greq is calculated according to the flowchart shown in FIG.
[0035]
In step 350, the control amount Dsj (j = fin, fout, rin, rout) of each wheel is calculated in accordance with the flowchart shown in FIG. 8, and in step 400, turning is performed in accordance with the flowchart shown in FIG. The control amount Dsrin of the inner rear wheel is corrected, and in step 450, the target wheel speed Vwti of each wheel is calculated according to the flowchart shown in FIG.
[0036]
In step 500, the duty ratio Dri (i = fl, fr, rl, rr) of each wheel is calculated according to the following equation (1). In the following equation 1, Kp and Kd are proportional constants of a proportional term and a differential term in wheel speed feedback control.
[Expression 1]
Dri = Kp * (Vwi-Vwti) + Kd * d (Vwi-Vwti) / dt
[0037]
In step 550, a control signal is output to the switching valves 42 and 44 and the control valves 28, 50FL and 50FR, so that the control valve is switched to the second position, and the opening / closing valve of each wheel is also set. On the other hand, by supplying a control signal corresponding to the duty ratio Dri, supply / discharge of the accumulator pressure to the wheel cylinders 48FL, 48FR, 66RL, 66RR is controlled, thereby controlling the braking pressure of each wheel.
[0038]
In this case, when the duty ratio Dri is a value between the negative reference value and the positive reference value, the upstream side open / close valve is switched to the second position and the downstream side open / close valve is held at the first position. As a result, the pressure in the corresponding wheel cylinder is maintained, and when the duty ratio is greater than the positive reference value, the upstream and downstream on / off valves are controlled to the positions shown in FIG. When the accumulator pressure is supplied to the wheel cylinder, the pressure in the wheel cylinder is increased, and when the duty ratio is less than the negative reference value, the upstream and downstream on-off valves are switched to the second position. As a result, the brake oil in the corresponding wheel cylinder is discharged to the low-pressure conduit 52, whereby the pressure in the wheel cylinder is reduced.
[0039]
In step 102 of the spin state quantity SS calculation routine shown in FIG. 3, the deviation of the lateral acceleration, i.e., the deviation of the lateral acceleration, i.e. The side slip acceleration Vyd is calculated, and in step 104, the side slip acceleration Vyd is integrated to calculate the side slip velocity Vy of the vehicle body, and the ratio Vy of the vehicle body side slip velocity Vy to the vehicle body longitudinal speed Vx (= vehicle speed V). The slip angle β of the vehicle body is calculated as / Vx.
[0040]
In step 106, the spin value SV is calculated as a linear sum K1 * β + K2 * Vyd of the slip angle β and the side-slip acceleration Vyd of the vehicle body with K1 and K2 being positive constants, respectively. In step 108, the sign of the yaw rate γ is calculated. Based on this, the turning direction of the vehicle is determined, and the spin state amount SS is calculated as SV when the vehicle is turning left, -SV when the vehicle is turning right, and the spin state amount is 0 when the calculation result is negative. Is done. The spin value SV may be calculated as a linear sum of the slip angle β of the vehicle body and its differential value βd.
[0041]
Further, in step 152 of the drift-out state quantity DS calculation routine shown in FIG. 4, the target yaw rate γc is calculated according to the following equation 2 with Kh as the stability factor, H as the wheel base, and Rg as the steering gear ratio. At the same time, the reference yaw rate γt is calculated according to the following equation 3 using T as a time constant and s as a Laplace operator. The target yaw rate γc may be calculated in consideration of the lateral acceleration Gy of the vehicle in order to take into account the dynamic yaw rate.
[0042]
[Expression 2]
γc = V * θ / (1 + Kh * V²* H / Rg
[Equation 3]
γt = γc / (1 + T * s)
[0043]
In step 154, the drift value DV is calculated according to the following equation (4). The drift value DV may be calculated according to the following formula 5.
[Expression 4]
DV = (γt−γ)
[Equation 5]
DV = H * (γt−γ) / V
[0044]
In step 156, the turning direction of the vehicle is determined based on the sign of the yaw rate γ, and the drift-out state quantity DS is calculated as DV when the vehicle is turning left, and as -DV when the vehicle is turning right, and the calculation result When is a negative value, the drift-out state quantity is zero.
[0045]
In step 202 of the total yaw moment control amount Mt and total deceleration control amount Gt calculation routine shown in FIG. 5, the map corresponding to the graph shown in FIG. The yaw moment control amount Mts is calculated, and in step 204, the deceleration control amount Gts for the spin is calculated from the map corresponding to the graph shown in FIG. 12 based on the spin state amount SS.
[0046]
Similarly, in step 206, the yaw moment control amount Mtd for drift is calculated from the map corresponding to the graph shown in FIG. 13 based on the drift-out state quantity DS, and in step 208, the drift-out state quantity DS is calculated. Based on the map corresponding to the graph shown in FIG. 14, the deceleration control amount Gtd for drift is calculated.
[0047]
In step 210, it is determined whether or not the yaw moment control amount Mts for the spin is equal to or greater than the yaw moment control amount Mtd for the drift. If an affirmative determination is made, the total yaw moment control is performed in step 212. When the amount Mt is set to the yaw moment control amount Mts for spin and a negative determination is made, in step 214, the total yaw moment control amount Mt is set to the yaw moment control amount Mtd for drift.
[0048]
Similarly, in step 216, it is determined whether or not the deceleration control amount Gts for spin is greater than or equal to the deceleration control amount Gtd for drift. If an affirmative determination is made, the total deceleration control amount is determined in step 218. When Gt is set as the deceleration control amount Gts for spin and a negative determination is made, in step 220, the total deceleration control amount Gt is set as the deceleration control amount Gtd for drift.
[0049]
In step 252 of the target yaw moment control amount Mreq calculation routine shown in FIG. 6, the friction coefficient μ of the road surface with respect to the wheel is estimated and calculated according to the following equation 6, for example, with g as the gravitational acceleration. The upper limit value βrl is calculated from a map not shown in the figure based on the friction coefficient μ.
[Formula 6]
μ = (Gx²+ Gy²)^1/2/ G
[0050]
In step 256, the front wheel slip angle βf is calculated according to the following equation 7 with Lf as the distance between the center of gravity of the vehicle and the front wheel axle, and the front wheel actual steering angular velocity δfd is calculated as the front wheel actual steering angle δf (= θ / Rg) is calculated as a differential value, and further, a reference value βfs for calculating the rear wheel target slip angle βrt is calculated according to the following equation 8 using Ts as a phase advance time constant.
[0051]
[Expression 7]
βf = β + Lf * γ / V−θ / Rg
[Equation 8]
βfs = βf + Ts * δfd
[0052]
The reference value βfs may be calculated according to the following formula 9.
[Equation 9]
βfs = DV + Ts * δfd
[0053]
In step 258, the target slip angle βrt of the rear wheels is calculated from a map corresponding to the graph shown in FIG. 15 based on the reference value βfs. The slope of the straight line portion of the graph shown in FIG. 15 is given by assuming that Cf is the cornering power of the front wheel, Cr is the cornering power of the rear wheel, and Lr is the distance between the center of gravity of the vehicle and the rear wheel vehicle (Cf * Lf) / (Cr * Lr), and the upper and lower limits are βrl and -βrl, respectively.
[0054]
The rear wheel target slip angle βrt may be calculated according to the following equation 10 with C equal to the slope (Cf * Lf) / (Cr * Lr) of the graph shown in FIG.
[Expression 10]
βrt = βrl * tanh (βfs * C)
[0055]
In step 260, the yaw moment control coefficient Km is calculated according to the following equation 11, and in step 262, the target yaw moment control amount Mreq is calculated according to the following equation 12.
[0056]
## EQU11 ##
Km = βr−βrt + Vyd
[Expression 12]
Mreq = Km * Mt
[0057]
In step 302 of the target deceleration control amount Greq calculation routine shown in FIG. 7, the deceleration control coefficient Kg is calculated in step 252 and set to a value equal to the friction coefficient μ of the road surface. The target deceleration control amount Greq is calculated according to the following equation (13).
[Formula 13]
Greq = Kg * Gt
[0058]
In step 352 of the control amount Dsj calculation routine for each wheel shown in FIG. 8, based on the target yaw moment control amount Mreq, from the maps corresponding to the graphs shown in FIGS. The yaw moment distribution ratio Rmj (j = fin, fout, rin, rout) of the turning outer front wheel, the turning inner rear wheel, and the turning outer rear wheel is calculated. In step 354, the yaw moment of each wheel is calculated according to the following equation (14). A control amount Dsmj is calculated.
[Expression 14]
Dsmj = Rmj * Mreq
[0059]
In step 356, based on the target yaw moment control amount Mreq, the deceleration of the turning inner front wheel, the turning outer front wheel, the turning inner rear wheel, and the turning outer rear wheel from the maps corresponding to the graphs shown in FIGS. The distribution ratio Rdj (j = fin, fout, rin, rout) is calculated, and in step 358, the deceleration control amount Dsdj for each wheel is calculated according to the following equation (15).
[Expression 15]
Dsdj = Rdj * Greq
[0060]
In step 360, the control amount Dsj of each wheel is calculated according to the following equation 16 as the sum of the yaw moment control amount Dsmj and the deceleration control amount Dsdj.
[Expression 16]
Dsj = Dsmj + Dsdj
[0061]
In step 402 of the control amount Dsrin correction routine for the turning inner rear wheel shown in FIG. 9, the low pass filter processing value Dsrinf of the control amount Dsrin for the turning inner rear wheel one cycle before is rewritten to the previous value Dsrinff. Then, the control amount Dsrin of the current cycle is rewritten to the control amount Dsrinn before correction, and in step 404, the low-pass filter processing value Dsrinf of the control amount Dsrin of the turning inner rear wheel is calculated as a correction value according to the following equation 17. . In the following equation 17, the filter constant R is equal to Δt / T, where Δt is the cycle time of the flowchart shown in FIG. 2 and T is a time constant of about 1 second.
[Expression 17]
Dsrinf = (1-R) Dsrinff + R * Dsrinn
[0062]
In step 406, for example, it is determined whether or not the turning direction of the vehicle has been reversed by determining whether or not the product of the previous value and the current value of the yaw rate γ of the vehicle is negative. If YES in step 410, the flow directly proceeds to step 410. If an affirmative determination is made, the low pass filter processing value Dsrinf is set to 0 in step 408.
[0063]
In step 410, the control amount Dsrin after correction is calculated by subtracting the low-pass filter processing value Dsrinf from the control amount Dsrinn before correction of the inner rear wheel according to the following equation 18, and in step 412 It is determined whether the product of the control amount Dsrinn before correction and the control amount Dsrin after correction is negative, that is, whether the signs of the control amount Dsrinn before correction and the control amount Dsrin after correction are opposite to each other. When a negative determination is made, the process proceeds to step 450 as it is. When an affirmative determination is made, the corrected control amount Dsrin of the rear inner wheel is set to zero.
[Formula 18]
Dsrin = Dsrin-Dsrinf
[0064]
In step 452 of the target wheel speed Vti calculation routine shown in FIG. 10, it is determined whether or not the product of the vehicle lateral acceleration Gy and the target yaw moment control amount Nreq is positive, that is, the target. It is determined whether or not the yaw moment control amount is a yaw moment control amount in the turning assist direction. If an affirmative determination is made, the process proceeds to step 460, and if a negative determination is made, the process proceeds to step 454.
[0065]
In step 454, it is determined whether or not the yaw rate γ is positive, that is, whether or not the vehicle is turning left, and if an affirmative determination is made, in step 456, In step 458, the target wheel speed Vwti of each wheel is calculated in accordance with the following equation (20).
[0066]
[Equation 19]
Vwtfl = (1-Dsfin) Vwfr
Vwtfr = Vwfr
Vwtrl = (1-Dsrin) Vwfr
Vwtrr = (1-Dsrout) Vwfr
[Expression 20]
Vwtfl = Vwfl
Vwtfr = (1-Dsfin) Vwfl
Vwtrl = (1-Dsrout) Vwfl
Vwtrr = (1-Dsrin) Vwfl
[0067]
Similarly, in step 460, it is determined whether or not the yaw rate γ is positive. If an affirmative determination is made, in step 462, the target wheel speed Vwti of each wheel is calculated according to the following equation (21). When a negative determination is made, in step 464, the target wheel speed Vwti of each wheel is calculated according to the following equation (22).
[0068]
[Expression 21]
Vwtfl = Vwfl
Vwtfr = (1-Dsfout) Vwfl
Vwtrl = (1-Dsrin) Vwfl
Vwtrr = (1-Dsrout) Vwfl
[Expression 22]
Vwtfl = (1-Dsfout) Vwfr
Vwtfr = Vwfr
Vwtrl = (1-Dsrout) Vwfr
Vwtrr = (1-Dsrin) Vwfr
[0069]
Thus, according to the illustrated embodiment, the spin state quantity SS and the drift-out state quantity DS are calculated in steps 100 and 150, respectively, and in step 200 the total yaw moment control quantity Mt and The total deceleration control amount Gt is calculated, and in steps 250 and 300, the target yaw moment control amount Mreq and the target deceleration control amount Greq are calculated based on these control amounts.
[0070]
In step 350, the control amount Dsj of each wheel is calculated based on the target yaw moment control amount Mreq and the target deceleration control amount Greq. In step 450, the target wheel speed Vwti of each wheel is calculated. Then, the duty ratio Dri of each wheel is calculated based on the control amount Dsj, and the braking pressure of each wheel is controlled in accordance with the duty ratio Dri in step 550, whereby the vehicle is decelerated and the yaw moment necessary for the vehicle is calculated. Is given.
[0071]
For example, when the vehicle is in a spin state, the spin state amount SS becomes a high value, and the target yaw moment control amount Mreq and the target deceleration control amount Greq in the anti-spin direction are calculated correspondingly, and the control of each wheel is performed based on these. By calculating the amount Dsj, the vehicle is given a yaw moment in the anti-spin direction and the vehicle is decelerated, thereby reducing the spin state.
[0072]
When the vehicle enters the drift-out state, the drift-out state amount DS becomes a high value, and the target yaw moment control amount Mreq and the target deceleration control amount Greq in the turning assist direction are calculated correspondingly, and based on these, each wheel is calculated. By calculating the control amount Dsj, the vehicle is given a yaw moment in the direction of turning assistance and the vehicle is decelerated, thereby reducing the drift-out state.
[0073]
Particularly in this case, the control amount Dsrin of the rear inner wheel is corrected in step 400. That is, in step 402, the low-pass filter processing value Dsrinf of the control amount Dsrin of the turning inner rear wheel one cycle before is rewritten to the previous value Dsrinff, and the control amount Dsrin of the current cycle is rewritten to Dsrinn. The low pass filter processing value Dsrinf of the control amount Dsrin of the turning inner rear wheel is calculated as a correction amount, and the control amount Dsrinn before correction is subtracted by the low pass filter processing value Dsrinf in step 410, thereby correcting the turning inner side. The rear wheel control amount Dsrin is set.
[0074]
For example, if the control amount Dsrinn before correction of the turning inner rear wheel changes as shown in FIG. 24A, the correction amount Dsrinf changes as shown in FIG. The corrected control amount Dsrin changes as shown in FIG. Since the negative region of the corrected control amount Dsrin is set to 0, the control amount Dsrin of the turning inner rear wheel used for actual control is a control amount that changes as shown in FIG. Become.
[0075]
Therefore, even when the drift-out state continues for a relatively long time and the drift-out suppression control is performed for a relatively long time, the drift-out suppression control is prevented from being performed for a relatively long time with a relatively high control amount. The vehicle is reliably prevented from spinning slowly due to the suppression control, and the control amount of the other wheels is not corrected, so that it is avoided that the vehicle decelerates and the turning assist yaw moment is insufficient. This effectively suppresses the drift-out state.
[0076]
When the continuation of the drift-out state is relatively short, the correction amount Dsrinf does not become a high value, so the control amount Dsrin of the turning inner rear wheel used for actual control is not too small. The drift-out state is not effectively suppressed due to the lack of control amount of the rear wheels.
[0077]
In addition, according to the illustrated embodiment, when it is determined in step 412 that the product of the control amount Dsrinn before correction of the turning inner rear wheel and the control amount Dsrin after correction is negative, in other words, For example, when the sign of the corrected control amount Dsrin is different from the sign of the control amount Dsrinn before correction of the turning inner rear wheel, the corrected control amount Dsrin of the turning inner rear wheel is set to 0. It is reliably prevented that the behavior control is not appropriately performed due to the braking force of the inner rear wheel being controlled based on the control amount Dsrin after the inappropriate correction.
[0078]
When the turning direction of the vehicle is reversed, the previous value Dsrinff of the low-pass filter processing value Dsrinf is rewritten in step 402 and becomes an inappropriate value that cannot be applied to the control of the current cycle. The calculated low-pass filter processing value Dsrinf of the control amount Dsrin of the turning inner rear wheel is also an inappropriate correction amount for the control of the current cycle.
[0079]
According to the illustrated embodiment, when it is determined in step 406 that the turning direction of the vehicle has been reversed, the low-pass filter processing value Dsrinf as the corrected control amount is set to 0 in step 408. Therefore, it is reliably prevented that the control amount Dsrin of the turning rear rear wheel is corrected with an inappropriate correction amount, and thus behavior control is performed with an inappropriate control amount immediately after the turning direction is reversed. Is reliably prevented.
[0080]
According to the illustrated embodiment, the control amount Dsrin of the turning inner rear wheel is corrected even when the vehicle is in the spin state, but the control amount of the turning inner rear wheel is so high when the vehicle is in the spin state. However, the effect of the spin suppression control is not greatly reduced by correcting the control amount Dsrin of the turning inner rear wheel.
[0081]
Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to the above-described embodiments, and various other embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art.
[0082]
  For example, in the illustrated embodiment, the correction amount of the control amount Dsrin of the turning inner rear wheel is calculated as a low-pass filter processing value Dsrinf of the control amount Dsrin of the turning inner rear wheel in step 404. However, the correction amount is the control amount DsrinofGradient limit processingControl amount D srin Limit the slope of changeIt may be calculated by doing.
[0083]
In the illustrated embodiment, a spin state quantity SS and a drift-out state quantity DS are calculated, and based on these state quantities, a total yaw moment control amount Mt and a total deceleration control amount Gt are calculated. The target yaw moment control amount Mreq and the target deceleration control amount Greq are calculated based on the control amount, and the control amount Dsj of each wheel is calculated based on these control amounts, but the control amount Dsj is in a drift-out state. As long as it is calculated as a control amount for suppressing drift-out based on the amount, it may be calculated in an arbitrary manner.
[0084]
Further, in the illustrated embodiment, the deceleration and the turning assist yaw moment direction for suppressing the drift-out are achieved by controlling the braking force of each wheel. Or control of braking force and driving force of each wheel.
[0085]
【The invention's effect】
  As is apparent from the above description, the first aspect of the present invention is as follows.And 2With this configuration, the drift-out suppression control amount is corrected by subtracting the correction amount that gradually increases from the drift-out suppression control amount, and the vehicle decelerates based on the corrected drift-out suppression control amount. Or the vehicle is given a turning assist yaw moment, so that even when the drift-out state continues for a relatively long time and the drift-out suppression control is performed for a relatively long time, the drift-out suppression control is relatively It is possible to prevent the vehicle from slowly going into a spin state due to the drift-out suppression control.
  According to the third aspect of the invention, when the sign of the drift-out suppression control amount before correction and the drift-out suppression control amount after correction are different from each other, the corrected drift-out suppression control amount is set to 0. The drift-out suppression control is appropriately performed because the control that decelerates the vehicle or applies the turning assist yaw moment to the vehicle to reduce the drift-out state is performed based on an inappropriate corrected drift-out suppression control amount. It can be surely prevented that it is not performed.
  According to the fourth aspect of the present invention, the correction means determines the turning direction, and sets the correction amount to 0 when the turning direction is reversed. Therefore, the drift-out suppression control amount can be corrected with an inappropriate correction amount. Thus, it is possible to reliably prevent the drift-out suppression control from being performed with an inappropriate control amount immediately after the turning direction is reversed.
[0086]
  Claims of the invention5With this configuration, the vehicle is decelerated by braking at least the left and right rear wheels, and a turning assist yaw moment is applied to the vehicle, and only the control amount of the turning inner rear wheel is corrected. It is possible to prevent the braking force from becoming excessive and the lateral force from being insufficient,Other than turning inner rear wheelSince the control amount of the wheel is not corrected, it is possible to prevent the vehicle from decelerating and the turning assist yaw moment from becoming excessive and to effectively suppress the drift-out state.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a hydraulic circuit and an electric control device of one embodiment of a behavior control device according to the present invention.
FIG. 2 is a general flowchart showing an outline of behavior control achieved by one embodiment of the behavior control device according to the present invention.
FIG. 3 is a flowchart showing a calculation routine of a spin state quantity SS in the illustrated embodiment.
FIG. 4 is a flowchart showing a calculation routine of a drift-out state quantity DS in the illustrated embodiment.
FIG. 5 is a flowchart showing a calculation routine of a total yaw moment control amount Mt and a total deceleration control amount Gt in the illustrated embodiment.
FIG. 6 is a flowchart showing a calculation routine of a target yaw moment control amount Mreq in the illustrated embodiment.
FIG. 7 is a flowchart showing a calculation routine of a target deceleration control amount Greq in the illustrated embodiment.
FIG. 8 is a flowchart showing a calculation routine of a control amount Dsj for each wheel in the illustrated embodiment.
FIG. 9 is a flowchart showing a correction routine for a control amount Dsrin of the turning inner rear wheel in the illustrated embodiment.
FIG. 10 is a flowchart showing a calculation routine of a target wheel speed Vwti of each wheel in the illustrated embodiment.
FIG. 11 is a graph showing a relationship between a spin state amount SS and a spin yaw moment control amount Mts.
FIG. 12 is a graph showing a relationship between a spin state amount SS and a spin deceleration control amount Gts.
FIG. 13 is a graph showing a relationship between a drift-out state quantity DS and a drift yaw moment control quantity Mtd.
FIG. 14 is a graph showing a relationship between a drift-out state quantity DS and a drift deceleration control quantity Gtd.
FIG. 15 is a graph showing a relationship between a reference value βfs and a rear wheel target slip angle βrt.
FIG. 16 is a graph showing a relationship between a target yaw moment control amount Mreq and a yaw moment distribution ratio Rmfin of a turning inner front wheel.
FIG. 17 is a graph showing the relationship between the target yaw moment control amount Mreq and the yaw moment distribution ratio Rmfout of the front wheel outside the turn.
FIG. 18 is a graph showing a relationship between a target yaw moment control amount Mreq and a yaw moment distribution ratio Rmrin of a turning inner rear wheel.
FIG. 19 is a graph showing the relationship between the target yaw moment control amount Mreq and the yaw moment distribution ratio Rmrout of the rear outer wheel.
FIG. 20 is a graph showing the relationship between the target yaw moment control amount Mreq and the deceleration distribution ratio Rdfin of the turning front wheel.
FIG. 21 is a graph showing the relationship between the target yaw moment control amount Mreq and the deceleration distribution ratio Rdfout of the front outside wheel.
FIG. 22 is a graph showing a relationship between a target yaw moment control amount Mreq and a deceleration distribution ratio Rdrin of the turning inner rear wheel.
FIG. 23 is a graph showing the relationship between the target yaw moment control amount Mreq and the deceleration distribution ratio Rdrout of the rear outer wheel.
FIG. 24 is a graph showing an example of changes in a control amount Dsrinn, a correction amount Dsrinf before correction, a control amount Dsrin after correction, and a control amount Dsrin for a turning inner rear wheel.
[Explanation of symbols]
10 ... Brake device
14 ... Master cylinder
16 ... Hydro Booster
20, 22, 32, 34 ... Brake hydraulic control device
28, 50FL, 50FR ... Control valve
42, 44 ... switching valve
44FL, 44FR, 64RL, 64RR ... Wheel cylinder
54FL, 54FR, 60RL, 60RR ... Open / close valve
56FL, 56FR, 62RL, 62RR ... Open / close valve
70: Electric control device
76 ... Vehicle speed sensor
78 ... Lateral acceleration sensor
80 ... Yaw rate sensor
82 ... Steering angle sensor
84: Longitudinal acceleration sensor
86FL-86RR ... Wheel speed sensor

Claims (5)

Means for estimating a drift-out state quantity of a vehicle; computing means for computing a drift-out suppression control amount based on at least the drift-out state quantity when the drift-out state quantity exceeds a reference value; and the drift-out suppression In the vehicle behavior control device, the drift-out suppression control amount having a control means for performing drift-out suppression control for reducing the drift-out state by decelerating the vehicle based on the control amount or applying a turning assist yaw moment to the vehicle. A correction amount that gradually increases in magnitude is obtained by low-pass filtering, and the drift-out suppression control amount is corrected by subtracting the correction amount that gradually increases in magnitude from the drift-out suppression control amount. have a correction means, the control means drift-out suppress control amount after corrected Behavior control device of a vehicle which is characterized in that the drift-out suppress control based. Means for estimating a drift-out state quantity of a vehicle; computing means for computing a drift-out suppression control amount based on at least the drift-out state quantity when the drift-out state quantity exceeds a reference value; and the drift-out suppression In the vehicle behavior control device, the drift-out suppression control amount having a control means for performing drift-out suppression control for reducing the drift-out state by decelerating the vehicle based on the control amount or applying a turning assist yaw moment to the vehicle. Is corrected by gradient limiting processing, and the drift-out suppression control amount is corrected by subtracting the correction amount that gradually increases from the drift-out suppression control amount. Correction means, the control means based on the corrected drift-out suppression control amount Serial behavior control device of a vehicle which is characterized in that a drift-out suppress control. Means for estimating a drift-out state quantity of a vehicle; computing means for computing a drift-out suppression control amount based on at least the drift-out state quantity when the drift-out state quantity exceeds a reference value; and the drift-out suppression In a vehicle behavior control device having a control means for performing drift-out suppression control for reducing a drift-out state by decelerating a vehicle based on a control amount or applying a turning assist yaw moment to the vehicle, the size gradually increases. A correction means for correcting the drift-out suppression control amount by subtracting the correction amount to be corrected from the drift-out suppression control amount, and the control means performs the drift-out suppression control based on the corrected drift-out suppression control amount. The correction means performs a drift-out suppression control amount before correction and a drift after correction. Behavior control device of the vehicle when the sign of Outs suppression control amount are different from each other, characterized in that setting the drift-out suppress control amount after corrected to zero. Means for estimating a drift-out state quantity of a vehicle; computing means for computing a drift-out suppression control amount based on at least the drift-out state quantity when the drift-out state quantity exceeds a reference value; and the drift-out suppression In a vehicle behavior control device having a control means for performing drift-out suppression control for reducing a drift-out state by decelerating a vehicle based on a control amount or applying a turning assist yaw moment to the vehicle, the size gradually increases. A correction means for correcting the drift-out suppression control amount by subtracting the correction amount to be corrected from the drift-out suppression control amount, and the control means performs the drift-out suppression control based on the corrected drift-out suppression control amount. The correction means determines the turning direction, and when the turning direction is reversed, Behavior control device of a vehicle, characterized in that setting the Seiryo to 0. The control means applies a turning assist yaw moment to the vehicle while decelerating the vehicle by braking at least the left and right rear wheels, and the correction means controls the rear inner wheels without correcting the control amount other than the rear inner wheels. 5. The vehicle behavior control device according to claim 1, wherein only the amount is corrected.

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