JP2002114059A - Overall control device for attitude control device for automobile and continuously variable transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfactorily recover a change gear ratio after an understeer state is resolved in a structure resolving the understeer state by the output reduction control of an engine and the change gear ratio control of a continuously variable transmission when the understeer state above the prescribed state occurs at a turn of a vehicle. SOLUTION: If the change gear ratio of the continuously variable transmission is changed from a predetermined change gear ratio on a variable speed characteristic to resolve the understeer state, this change gear ratio is recovered to the change gear ratio on the variable speed characteristic when the actual change gear ratio enters the prescribed range against the change gear ratio on the variable speed characteristic after the understeer state is resolved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overall control system for a vehicle aimed at resolving a posture of the vehicle at the time of turning, in particular, an understeer state, and relates to a field of vehicle running control technology.

[0002]

2. Description of the Related Art In recent years, vehicles have anti-skid brake systems that individually control the braking force of each wheel during braking to achieve good braking performance, and that the torque transmitted to the driving wheels is excessive. A traction control system that realizes good starting performance and acceleration performance by eliminating wheel slip due to the engine output and braking force control has been installed, but in addition to these systems, Alternatively, an attitude control system for stabilizing the behavior of a vehicle at the time of turning using the functions of these systems is being put to practical use.

In this system, when an understeer state or an oversteer state is detected during a turn, the attitude of the vehicle in the yawing direction is controlled by control of engine output reduction or brake force control for each wheel, thereby achieving a stable turn. The goal is to realize driving, but when this system is put into practical use, there is a problem of how to balance control by this system and shift control of the vehicle. See, for example,
Japanese Patent Application Laid-Open No. 0-236186 proposes an invention in which a shift operation of an automatic transmission is prohibited during attitude control during turning, and a shift speed is fixed.

Japanese Patent Application Laid-Open No. H11-44359 discloses a related art of the operation of the anti-skid brake system in a vehicle provided with the above-described anti-skid brake system and a belt-type continuously variable transmission. In the meantime, there is disclosed an invention in which the line pressure is increased and corrected in order to prevent the belt of the continuously variable transmission from slipping.

[0005]

When the understeer state during turning is eliminated by the above attitude control system, for example, control for reducing the number of combustion cylinders of the engine, retard control for the ignition timing, or reduction of the throttle opening degree is required. Controlling the engine output or the vehicle drive torque to reduce the vehicle speed, and applying a braking force to the inner wheel to apply a moment in the turning direction to the vehicle while further reducing the vehicle drive torque. In this case, the following inconvenience may occur, especially when the vehicle is underdriving, that is, when the driver intentionally generates an understeer state with the accelerator pedal depressed. become.

That is, if the engine output is reduced or the braking force is applied more than necessary in such an under-driven state, control contrary to the driver's intention is performed, and so-called control interference occurs. This causes the driver to feel uncomfortable or stalled. In particular, if the engine speed drops due to the engine output reduction control, the re-acceleration after the understeer state is resolved will deteriorate,
Further, heavy use of the brake control is a factor of destabilizing the behavior of the vehicle.

On the other hand, in the case of a vehicle equipped with a continuously variable transmission, it is possible to use both the attitude control by the engine control and the brake control as described above and the speed ratio control of the continuously variable transmission. Conceivable. That is, the vehicle drive torque is reduced by, for example, shifting up the speed ratio of the continuously variable transmission when the understeer state is detected,
To avoid the execution of brake control as much as possible, to suppress a decrease in engine output and engine speed, to stabilize the vehicle posture and eliminate stall sensation, etc., and to improve re-acceleration after eliminating the understeer state. Is conceivable.

However, when the speed ratio of the continuously variable transmission is changed from the speed ratio on the speed change characteristic set in advance in accordance with the operating condition as described above, after the elimination of the understeer condition, If the timing is too early, the running state becomes unstable due to a large change in the gear ratio.On the other hand, if the timing is too late, Running at the gear ratio is forced for a long time, and the running performance deteriorates. In particular, when the return of the gear ratio is downshifted, the driving torque is increased again, and the understeer state that has been eliminated is once again caused, thereby causing a poor behavior of the vehicle.

Therefore, according to the present invention, after the understeer state is eliminated by the speed ratio control of the continuously variable transmission, this speed ratio is smoothly returned to a speed ratio with a predetermined speed characteristic in accordance with the operating condition. That is the task.

[0010]

Means for Solving the Problems In order to solve the above-mentioned problems, an integrated control device for an automobile according to the present invention is characterized in that it is configured as follows.

First, the invention according to claim 1 (hereinafter referred to as first invention)
The invention relates to an attitude control device that controls the attitude of the vehicle in the yawing direction during turning by individually controlling the output of the engine and the braking force of the left and right wheels, and a shift control based on a preset shift characteristic. In an automobile equipped with a continuously variable transmission capable of continuously changing the ratio, an understeer detecting means for detecting an understeer state of the vehicle at the time of turning, an engine output reducing means for reducing an engine output, and a continuously variable transmission. A gear ratio changing means for changing a gear ratio from a gear ratio on the gear characteristic, and when the understeer state is detected by the understeer detecting means,
Control means for reducing the vehicle driving torque by engine output reduction control by the engine output reduction means and speed ratio control of the continuously variable transmission by the speed ratio changing means; determination means for determining the elimination of the understeer state; When it is determined by the means that the understeer state has been resolved, when the actual speed ratio of the continuously variable transmission falls within a predetermined range with respect to the speed ratio on the speed characteristic, the speed ratio is changed to the speed on the speed characteristic. And a gear ratio return means for returning to a gear ratio.

Further, the invention according to claim 2 (hereinafter referred to as second invention)
In the first aspect of the present invention, the speed ratio return means determines that the actual speed ratio falls within a predetermined range with respect to the speed ratio in the speed change characteristic when the running state of the vehicle shifts to the straight running state. It is characterized in that the speed ratio is returned to the speed ratio in the speed characteristics without waiting.

The invention according to claim 3 (hereinafter referred to as “third”)
In the first aspect of the present invention, the gear ratio return means includes an actual gear shift when the return to the gear ratio in the gear characteristic is upshifted when the determination means determines that the understeer state is eliminated. The present invention is characterized in that the speed ratio is returned to the speed ratio according to the speed characteristics without waiting for the ratio to fall within a predetermined range with respect to the speed ratio according to the speed characteristics.

The invention according to claim 4 (hereinafter referred to as the fourth invention)
In the first aspect of the present invention, the speed ratio return means is configured such that when the determination means determines that the understeer state is eliminated, the actual speed ratio is changed to the speed characteristic when the throttle opening of the engine is fully closed. The present invention is characterized in that the gear ratio is returned to a gear ratio based on gear characteristics without waiting for the gear ratio to fall within a predetermined range.

Further, according to a fifth aspect of the present invention (hereinafter referred to as a fifth aspect), in the first aspect as well, the speed ratio return means depresses the accelerator pedal after the determination means determines that the understeer state has been eliminated. When
The present invention is characterized in that the speed ratio is returned to the speed ratio according to the speed characteristics without waiting for the actual speed ratio to fall within a predetermined range with respect to the speed ratio according to the speed characteristics.

The invention according to claim 6 (hereinafter referred to as sixth invention)
In the fifth aspect of the present invention, in the fifth aspect, when the speed ratio is returned to a speed ratio based on the speed characteristics by depressing an accelerator pedal, the speed ratio is returned by a predetermined amount or more in a downshift direction. When it is to be changed, the change is suppressed.

According to a seventh aspect of the present invention (hereinafter referred to as a seventh aspect), in any one of the first to fifth aspects, the speed ratio return means is arranged so that the actual speed ratio has an effect on speed characteristics. When the speed ratio is returned to the speed ratio based on the speed characteristics without waiting for the speed ratio to fall within a predetermined range, the speed is gradually restored.

With the above configuration, each invention of the present application operates as follows.

First, according to the first aspect of the present invention, when an understeer state is detected during turning, the engine output reduction means controls the engine output and the transmission means controls the speed ratio of the continuously variable transmission. The vehicle driving torque is reduced, thereby eliminating the understeer state.

When the understeer state is eliminated, the speed ratio of the continuously variable transmission is returned to a speed ratio on the speed characteristics set in advance according to the operating state.
This return operation is performed when the actual gear ratio falls within a predetermined range with respect to the gear ratio in the gear characteristics. Therefore, a significant change in the gear ratio when the understeer state is resolved is prevented, and a smooth transition to a normal running state is achieved.

In this case, according to the second aspect of the present invention, if the traveling state of the vehicle shifts to the straight traveling state, it is possible to wait for the actual speed ratio to fall within a predetermined range with respect to the speed ratio on the speed change characteristic.
Since the speed ratio is immediately returned to the speed ratio on the speed change characteristic, it is possible to continue running at an inappropriate speed ratio after shifting to a straight traveling state in which the change in the speed ratio does not particularly deteriorate the vehicle behavior. It is avoided and the vehicle immediately returns to normal running performance.

According to the third aspect of the present invention, when the return to the speed ratio on the speed change characteristic is an upshift, that is, even if the speed ratio is immediately returned to the speed ratio on the speed change characteristic, the understeer caused by the increase in the driving torque is achieved. When there is no possibility that the state will re-occur, as in the case of the second aspect, without waiting for the actual gear ratio to fall within a predetermined range with respect to the gear ratio in the gear characteristic, the gear ratio is immediately changed. Therefore, it is possible to avoid running the vehicle at an inappropriate speed ratio.

Further, according to the fourth aspect, when the throttle opening is fully closed when the understeer state is eliminated, or when the throttle opening degree is fully closed after the understeer state is eliminated, In any case, if there is no danger of deterioration of the running state or re-generation of the understeer state even if the gear ratio is immediately returned to the gear ratio in the gear characteristic, the actual gear ratio is changed as in the second and third aspects. The gear ratio is immediately returned to the gear ratio without waiting for the gear ratio to fall within a predetermined range. Therefore, also in this case, it is avoided to continue running at an inappropriate speed ratio.

On the other hand, according to the fifth aspect, when the accelerator pedal is depressed after the determination means determines that the understeer state has been eliminated, the speed ratio immediately returns to the speed ratio in the speed change characteristic. Therefore, the driver's acceleration request is prioritized, and required acceleration can be obtained without delay.

In this case, according to the sixth aspect of the invention, when the return to the speed ratio in the speed change characteristic changes the speed ratio in the downshift direction by a predetermined amount or more, the change is suppressed. The re-generation of the understeer state and the like due to the significant downshift of the gear ratio can be avoided.

According to the seventh aspect, in any one of the first to fifth aspects, without waiting for the actual speed ratio to fall within a predetermined range with respect to the speed ratio in the speed change characteristic, When the speed ratio is returned to the speed ratio based on the speed change characteristic, since the speed is gradually restored, the instability of the vehicle behavior due to a sudden change in the speed ratio is prevented.

[0027]

Embodiments of the present invention will be described below.

First, a control system according to this embodiment will be described with reference to FIG. 1. This system has a control unit 10, which has wheel speed sensors 11,... A steering angle sensor 12 for detecting a steering angle of a steering wheel, a yaw rate sensor 13 for detecting a yaw rate generated in the vehicle, a lateral acceleration sensor 14 for detecting a lateral acceleration of the vehicle, a throttle opening for detecting a throttle opening of the engine. Degree sensor 15, a stop lamp switch 16 for canceling the control of the anti-skid brake system, an engine speed sensor 17 for detecting the engine speed, a shift position sensor 18 for detecting a shift position such as forward / reverse of the continuously variable transmission. , Master cylinder as hydraulic pressure source in brake system Signals are inputted from a fluid pressure sensor 19 for detecting a fluid pressure, a fluid level switch 20 for detecting a brake fluid level in a reservoir tank in the brake system, and an accelerator opening sensor 21 for detecting an accelerator opening. It has become.

The control unit 10 also provides an ABS lamp 31 indicating that the anti-skid brake system is operating, and a pressurizing motor for operating a pressurizing pump provided as a second hydraulic pressure source in the brake system. 32, a front solenoid valve 33 and a rear solenoid valve 34 as a pressurizing / depressurizing means for supplying / discharging brake fluid to / from a brake device provided for each wheel, communication between the master cylinder and the brake device for each wheel, A TSW solenoid valve 35 serving as a pressurizing / depressurizing means for shutting off, an ASW solenoid valve 36 serving as a pressurizing / depressurizing means for communicating and disconnecting between the master cylinder and the pressurizing pump, an engine controller 37 controlling the engine output, When vehicle attitude control is being performed, Alarm device 38 informing the rolling's line pressure actuator 39 to control the line pressure of the CVT, and also adapted to output a control signal to the shift actuator 40 to control the transmission ratio of the continuously variable transmission.

The control unit 10
Receives signals from the above-mentioned sensors or switches 11 to 21 and performs predetermined processing to execute the above-described devices 31 to 4.
In order to output a control signal to 0, it is configured as follows.

That is, the control unit 10
Is the anti-skid brake system (ABS) 51
A braking force distribution device 52 that distributes a braking force so that the rear wheels do not lock during braking, and a traction control system (a traction control system that prevents the driving wheels from slipping due to excessive driving force transmitted to the driving wheels). TCS) 53
An attitude control device 54 for controlling the attitude of the vehicle in the yawing direction at the time of turning; and a transmission for controlling the operations of the line pressure actuator 39 and the speed change actuator 40 to control the attitude of the vehicle by operating the continuously variable transmission. And a control device 55.

In the control unit 10, based on the signals from the wheel speed sensors 11...
As a result, the wheel speed of each wheel and the estimated vehicle speed are calculated, and these values are input to the ABS 51, the braking force distribution device 52, the TCS 53, and the attitude control device 54.

The signal from the stop lamp switch 16 is input to the ABS 51, the braking force distribution device 52, the TCS 53, and the attitude control device 54 via the stop lamp determination unit 63.

The signals from the engine speed sensor 17, the throttle opening sensor 15 and the shift position sensor 18 are respectively supplied to the engine speed calculating section 64, the throttle opening taking section 65 and the shift position judging section 66.
Are input to the TCS 53, the attitude control device 54, and the transmission control device 55 via the

The signals from the steering angle sensor 12, the yaw rate sensor 13, the lateral acceleration sensor 14 and the hydraulic pressure sensor 19 are supplied to the steering angle calculating section 67, the yaw rate calculating section 68, the lateral acceleration calculating section 69 and the hydraulic pressure calculating section, respectively. The steering angle, the yaw rate, the lateral acceleration and the master cylinder hydraulic pressure are calculated based on these signals. These values are input to the attitude control device 54 and the transmission control device 55.

Further, the signal from the liquid level switch 20 is sent to the TCS 5 through the liquid level determination unit 71.
3 and the attitude control device 54, respectively.
The signal from the accelerator opening sensor 21 is input to the transmission control device 55 via the accelerator opening calculating unit 72.

The ABS 51 calculates a control amount based on each of the input signals, and sends a signal to the ABS lamp 31, the pressurizing motor 32, the front solenoid valve 33, and the rear solenoid valve 34 according to the calculation result. Is output to control these operations. Further, the braking force distribution device 52 controls the operation of the rear solenoid valve 34.

The TCS 53 includes a pressing motor 3
2. Outputs signals to the front solenoid valve 33, the rear solenoid valve 34, the TSW solenoid valve 35, and the engine controller 37 to control the operation thereof.

Further, the attitude control device 54 includes a pressure motor 32, a front solenoid valve 33, a rear solenoid valve 34, a TSW solenoid valve 35, an ASW
A signal is output to the solenoid valve 36, the engine controller 37, and the alarm device 38 to control the operation thereof.

The transmission control unit 55 outputs signals to the line pressure actuator 39 and the transmission actuator 40 to control their operations.

Here, as an example of the continuously variable transmission controlled by the transmission control device 55, a toroidal type continuously variable transmission used in this embodiment will be described. As shown in FIG. The step transmission 80 is interposed between the output shaft 82 of the engine 81 and the drive shaft 84 of the drive wheels 83, 83, and continuously changes the output rotation of the engine 81 to be transmitted to the drive wheels 83, 83. It is configured to be.

That is, the toroidal type continuously variable transmission 8
Reference numeral 0 denotes a pair of input disks 85, 85 connected to the output shaft 82 of the engine 81, and the drive shaft 8 is disposed so that both surfaces thereof face the input disks 85, 85.
4 is arranged between the opposing surfaces of the output disk 86 and the input disk 85 and the output disk 86 and brought into frictional contact therewith, thereby transmitting torque between the disks 85 and 86. Friction roller 87 to be performed ...
87, the tilt angle of these friction rollers 87 is changed by hydraulic pressure to change the turning radius of the point of contact with the two disks 85, 86, so that the engine output shaft 82 moves to the drive shaft 84. Is configured to continuously change the power transmission.

As shown in FIG. 3, the continuously variable transmission 80 has a target engine speed corresponding to the vehicle speed and the throttle opening according to the shift map stored in the transmission control unit 55. The gear ratio is controlled at the same time.

Next, the attitude control of the vehicle in the yawing direction during turning by the attitude control device 54 and the transmission control device 55 in the control unit 10 will be described. In this embodiment, the control for eliminating oversteer is performed only by the attitude control device 54, and the control for eliminating understeer is performed by the attitude control device 54 and the transmission control device 55.

First, the outline of these controls will be described.
The oversteer elimination control is based on the actual yaw rate detected by the yaw rate sensor 13 and actually generated in the vehicle.
Is detected to be greater than the target yaw rate ψ0 by a predetermined amount or more, that is, when the yawing angle of the vehicle is increasing at an excessively high speed, the braking force is applied to the front wheels outside the turning direction to cause the vehicle to move in the opposite direction to the turning direction. This is accomplished by generating a directional moment, which eliminates the oversteer condition.

Understeer elimination control is performed when the actual yaw rate ψ is detected to be smaller than the target yaw rate ψ0 by a predetermined amount or more, that is, when the increasing speed of the yawing angle of the vehicle is not sufficient. The control is performed by lowering the vehicle driving torque or the vehicle speed by controlling the speed ratio of the step transmission 80, and, if necessary, controlling to apply a braking force to the wheels inside the turning direction. As a result, the cornering force for countering the centrifugal force acting on the vehicle is restored, and the moment in the turning direction is given, so that the understeer state is eliminated.

Next, the overall operation of this attitude control will be described with reference to the flowchart shown in FIG.

First, in step S1, the control unit 10 controls the various sensors and switches 11 shown in FIG.
, And at step S2,
The first target yaw rate ψ (θ) corresponding to the steering angle θ calculated by the steering angle calculation unit 67 based on the signal from the steering angle sensor 12
And a second target yaw rate ψ (G) corresponding to the lateral acceleration G calculated by the lateral acceleration calculator 69 based on the signal from the lateral acceleration sensor 14.

Specifically, the first target yaw rate ψ (θ) is obtained by calculating the estimated vehicle speed V calculated by the estimated vehicle speed calculator 62 based on the signals from the wheel speed sensors 11. Using the steering angle θ calculated by the calculation unit 67, calculation is performed according to the following equation (1). Here, in equation (1), K is a stability factor of the vehicle, and L is a wheelbase.

{(Θ) = V × θ / {(1 + K × V2) × L} (1) The second target yaw rate ψ (G) is calculated based on the estimated vehicle speed V and the lateral acceleration. Using the lateral acceleration G calculated by the calculation unit 69, calculation is performed according to the following equation (2).

Ψ (G) = G / V (2) Next, in step S3, the control unit 10
It is determined whether the absolute value of the first target yaw rate ψ (θ) is smaller than the absolute value of the second target yaw rate ψ (G). This determination is based on the first and second target yaw rates ψ (θ),
This is performed to set the smaller absolute value of ψ (G) to the target yaw rate ψ0 for the following vehicle attitude control.

That is, if YES is determined in step S3 (| ψ (θ) | <| ψ (G) |), the process proceeds to step S4.
And the first target yaw rate ψ (θ) according to the steering angle θ
Is set as the control target yaw rate ψ0, and in step S5, a deviation Δψ between the control target yaw rate ψ0 and the actual yaw rate ψ calculated by the yaw rate calculator 68 based on the signal from the yaw rate sensor 13 is calculated. Where the deviation Δ
ψ is defined as the absolute value of the difference between the actual yaw rate ψ and the control target yaw rate ψ0 (Δψ = | ψ−ψ0 |).

If the determination in step S3 is NO (| ψ (θ) | ≧ | ψ (G) |), the process proceeds to step S6.
And the second target yaw rate ψ according to the lateral acceleration G
A control target yaw rate # 0 is set based on (G).
At this time, the control target yaw rate ψ0 is corrected using the steering angle component according to the following equation (3). Here, equation (3)
Where k is a constant smaller than 1.

Ψ0 = ψ (G) + k × [ψ (θ) -ψ (G)] (3) Then, in step S5, the deviation Δ こ の between the corrected control target yaw rate ψ0 and the actual yaw rate ψ. Is calculated.

Here, when the second target yaw rate ψ (G) corresponding to the lateral acceleration G is set to the control target yaw rate ψ0, the correction using the steering angle component is performed when the driver intentionally understeers. Is generated, that is, in the case of under driving, unnecessary intervention of posture control is avoided.

In other words, the understeer state includes a case in which the turning operation of the vehicle cannot follow the steering of the driver due to overspeed, and a case in which the driving force is increased by keeping the steering angle constant. And the operation performed by the above operation. And the second based on the lateral acceleration G
When the target yaw rate ψ (G) becomes the control target yaw rate ψ0, it is not possible to determine which of the above two types of understeer state is based on only the lateral acceleration G.

Therefore, when the second target yaw rate ψ (G) is set to the control target yaw rate ψ0, the target value is corrected by using the steering angle component so as to increase the target value. At the time of speed, the attitude control is actively performed, while in the case of under driving, intervention of the attitude control is suppressed. In this case, by changing the constant k according to the lateral acceleration G corresponding to the road surface friction coefficient or the like, the posture control device is always interposed at appropriate timing according to the road surface friction state.

As described above, in step S5, the deviation Δψ of the actual yaw rate に 対 す る from the control target yaw rate ψ0
Is calculated, the control unit 10 next executes step S7, and sets a threshold value Δψos for determining whether to perform oversteer elimination control and a threshold value Δψus for determining whether to perform understeer elimination control, respectively. Set.

When the actual yaw rate よ り 大 き い is larger than the control target yaw rate ψ0 (during oversteer) and the deviation Δψ, which is the absolute value of the difference, is larger than the threshold value Δψos, the control unit 10 proceeds to step S8. To step S9 to perform control to eliminate the oversteer state. When the actual yaw rate よ り 小 さ い is smaller than the control target yaw rate ψ0 (during understeer), the deviation Δψ which is the absolute value of the difference is also used.
Is larger than the threshold value Δψus, step S
Steps S11 to S11 are executed to perform control for eliminating the understeer state.

Next, the understeer elimination control in step S11, which is a feature of the present invention, will be described in more detail.

This control is performed according to the flowchart shown in FIG. 5. First, in step S21, it is determined whether or not the deviation Δψ of the actual yaw rate に 対 す る from the control target yaw rate ψ0 is larger than a predetermined value Δψ0.

If the deviation Δψ is larger than the predetermined value Δψ0, that is, if the actual yaw rate ψ largely deviates from the target yaw rate ψ0 (understeer side), step S22 is executed to execute engine control and The understeer elimination control by the brake is immediately performed without performing the understeer elimination control by the speed ratio control or the like of the continuously variable transmission. In other words, in this case, it is necessary to reduce the vehicle speed promptly and apply a moment in the turning direction to the vehicle to surely eliminate the understeer state.

When the brake control is performed, step S23 is executed, and the speed ratio of the continuously variable transmission is controlled in accordance with the driving state based on the map shown in FIG. However, the change in the gear ratio is controlled so as to be slower than during normal traveling. This is because, when the understeer state needs to be eliminated promptly as described above, it is necessary to suppress the change in the gear ratio and to effectively perform the understeer elimination control by the brake.

If it is determined in step 21 that the deviation Δψ is equal to or smaller than the predetermined value Δψ0, the process proceeds to step S24.
Is performed, and it is determined whether or not the driver has depressed the brake pedal based on the signal from the hydraulic pressure sensor 19 that detects the hydraulic pressure of the master cylinder. When the driver is depressing, the above-described step S22 is executed, and only understeer elimination control by the brake is executed as in the case where the deviation Δψ is larger than the predetermined value Δψ0. This is because when the brake pedal is depressed, the vehicle attitude is governed by the state of the brake, and the engine control and the gear ratio control have little meaning.

On the other hand, when the deviation Δψ is equal to or less than the predetermined value Δψ0 and the driver does not depress the brake pedal, in other words, the understeer state is determined to be underdrive based on the driver's intentional driving operation. If it is determined, the target down amount ΔT0 of the vehicle driving torque T is calculated based on the yaw rate で in step S25.

The calculation of the target torque reduction amount ΔT0 is as follows.
This is performed as follows based on the maps shown in FIGS. That is, the first torque down amount ΔT1 corresponding to the magnitude of the deviation Δψ from the map of FIG. 6 is changed to the second torque down amount ΔT2 corresponding to the change rate of the deviation Δψ from the map of FIG.
Respectively, and these torque down amounts ΔT1, ΔT
By adding 2, the target torque down amount ΔT0 is calculated (ΔT0 = ΔT1 + ΔT2).

Here, as shown in FIG. 6, the first torque down amount ΔT1 is set so as to increase as the deviation Δψ increases to a certain limit in a region where the deviation Δψ is equal to or larger than a predetermined value.

As shown in FIG. 7, in the region where the absolute value of the rate of change of the deviation Δψ is equal to or greater than a predetermined value, the rate of change of the deviation The rate of change of the deviation Δψ is set to increase in the minus direction (direction in which the deviation Δψ decreases) so as to increase in the plus direction as the value increases in the direction of increasing Δψ.

Then, in step S26, the target driving torque T0 is calculated by subtracting the target torque reduction amount ΔT0 obtained as described above from the current vehicle driving torque T, and in step S27, the target driving torque T0 is calculated. Target change amount ΔR0 of the speed ratio R of the continuously variable transmission for achieving
Is calculated.

In calculating the target change amount ΔR0,
The engine output characteristic map shown in FIG. 8 is used. That is,
When the speed ratio R of the continuously variable transmission is changed in an operating state of an engine to reduce the vehicle driving torque T, generally, the speed ratio is shifted up to reduce the amplification factor with respect to the engine output torque. At this time, in the hatched region in FIG. 8, the engine output torque itself increases due to the decrease in the engine speed due to the shift-up, so that the vehicle drive torque T does not always decrease. Will be. Therefore, the target change amount ΔR0 of the speed ratio of the continuously variable transmission for realizing the target drive torque T0 is calculated based on the current speed ratio R and the engine output characteristic map of FIG. It is calculated.

In step S28, the allowable change amount ΔRa of the speed ratio R of the continuously variable transmission according to the current state of the vehicle is determined.
Is set according to the maps of FIGS. 9 to 11. That is, the allowable change amount ΔRa of the gear ratio according to the vehicle speed is obtained from the map of FIG.
And the first and second correction coefficients K1 and K2 corresponding to the current steering angle and the throttle opening are read from the maps of FIGS. 10 and 11, respectively. Then, the base value ΔRa0 of the allowable change amount read from the map of FIG. 9 is corrected by multiplication of these correction coefficients K1 and K2, and the final allowable change amount ΔRa of the speed ratio R is corrected.
(= ΔRa0 × K1 × K2) is calculated.

Here, as shown in FIG. 9, the base value ΔRa0 of the permissible change amount is set so as to decrease as the vehicle speed increases, that is, the permissible range is narrowed. Is smaller on the shift-down side than on the shift-up side. This is to cope with the fact that the vehicle behavior becomes unstable due to a change in the gear ratio, which becomes remarkable as the vehicle speed increases, and that the downshift becomes larger than the upshift.

As shown in FIGS. 10 and 11,
The first and second correction coefficients K1 and K2 are set so as to become smaller as the steering angle and the throttle opening increase within a range of 1 or less, and in both cases, the downshift is more than the upshift. It is a small value. This is because the instability of the vehicle behavior due to the change of the gear ratio becomes more pronounced as the steering angle is larger and the throttle opening is larger, and the downshift is larger than the upshift. Therefore, in these cases, the allowable change range of the gear ratio is limited narrowly.

As described above, the speed ratio R of the continuously variable transmission for realizing the torque reduction to the target drive torque T0.
After calculating the target change amount ΔR0 and the allowable change amount ΔRa, in step S29, whether the target change amount ΔR0 is smaller than the allowable change amount ΔRa, that is, the target change amount ΔR0 of the gear ratio is determined. It is determined whether it is within the allowable range.
And when it is within the allowable range, in step S30,
The gear ratio control is performed such that the gear ratio R of the continuously variable transmission is changed by the target change amount ΔR0.

Thus, by changing the speed ratio R within the allowable range, the vehicle drive torque T is reduced to the target drive torque T0 without causing a vehicle behavior defect or the like, and the understeer state is eliminated.

On the other hand, when it is determined in step S29 that the target change amount ΔR0 of the speed ratio R is equal to or larger than the allowable change amount ΔRa, that is, the drive torque T is changed to the target drive torque T0 only by the change in the speed ratio within the allowable range. If it is determined that it cannot be reduced, the engine output reduction control of step S31 and subsequent steps is executed. First, in step S31, it is determined whether or not a torque reduction to the target drive torque T0 is realized by retard control of the ignition timing. I do. Then, when it is determined that the torque reduction to the target drive torque T0 is realized by the retard control, in step S32, the retard control of the ignition timing is executed so that the target drive torque T0 is realized.

If it is determined that the torque cannot be reduced to the target drive torque T0 only by the retard control of the ignition timing, the engine output reduction control centering on the reduction control of the number of combustion cylinders and the reduction of the number of cylinders are performed in step S33. The control for reducing the vehicle drive torque T to the target drive torque T0 is performed by using together with the speed ratio control of the continuously variable transmission for interpolating the stepwise change of the engine output due to the control.

The engine output reduction control and the gear ratio control in steps S32 and S33 are performed as follows using a torque down characteristic map of the engine as shown in FIGS.

That is, FIG. 12 shows how the engine output torque when the throttle is fully opened in the warm state of the engine is reduced by the retard control of the ignition timing and the reduction control of the number of combustion cylinders. Region A shows a range in which the output torque is reduced by the retard of the ignition timing in the all-cylinder operation state, region B shows a range in which the output torque is reduced by the retard of the ignition timing in the one-cylinder reduced state, and region C shows the range in which the output torque is reduced by one. The range in which the output torque is reduced by retarding the ignition timing in the cylinder reduction state is shown. The characteristic indicated by the curve D indicates the output torque in a state where three cylinders are reduced. Although not shown, similar torque-down characteristics are set for each intermediate throttle opening.

FIG. 13 shows how the engine output torque when the throttle is fully opened in a cold state of the engine is changed by the retard control of the ignition timing and the control of reducing the number of combustion cylinders. Similarly to the case of the warm state, the area A 'shows the range in which the output torque is reduced by the retard of the ignition timing in the all-cylinder operation state, but in the cold state, the ignition timing is reduced with the number of combustion cylinders reduced. Are not used because the combustion state is significantly deteriorated when the retardation is retarded. Therefore, the combustion cylinder number reduction state is represented by curves B ′, C ′ and D ′, respectively, as shown in FIG.
Only the output torque characteristics in the cylinder reduction state, the two cylinder reduction state, and the three cylinder reduction state are shown. Although not shown, a similar torque-down characteristic is set for each intermediate throttle opening in this cold state.

The torque-down characteristic maps of FIGS. 12 and 13 show that the first and second non-operable areas X,
X ', Y, and Y' are set. Of these,
The first inoperable regions X and X 'are regions where the engine may stall when the rotational speed is reduced to this region,
The second non-operable regions Y and Y 'indicate regions where the exhaust gas purifying catalyst may be deteriorated at an early stage by high-speed operation with the reduced number of combustion cylinders.

If it is determined in step S32 of the flowchart of FIG. 5 that torque reduction to the target drive torque T0 can be realized only by retard control of the ignition timing, the region A, A '(or the intermediate throttle) in FIG. The retard control is performed within the same area in the same map of the opening degree). In step S33, in order to realize the torque reduction to the target drive torque T0,
When the output reduction control of the engine and the speed ratio control of the continuously variable transmission are used together, these controls are performed as follows.

For convenience, this control will be described with reference to FIG. 12 which shows the characteristics when the throttle is fully opened in a warm state. In order to reduce the torque to the target drive torque T0, the engine output torque is reduced. When I tried,
When the output torque becomes, for example, a point indicated by reference numeral P1 in the area B, the number of combustion cylinders is reduced by one, and
The output torque is reduced to the value of the point P1 by the retard control of the ignition timing in the region B (arrow A). The same applies to the case in the region C. However, when the engine output torque to be reduced is the torque on the characteristic D, the number of combustion cylinders is reduced by three.

On the other hand, the engine output torque for realizing the torque reduction to the target drive torque T0 is in the regions E, F and G which cannot be realized by the above-described engine combustion cylinder number reduction control and ignition timing retard control. If so, the speed ratio control of the continuously variable transmission is performed in addition to these engine controls.

That is, for example, when the engine output torque for realizing the torque reduction to the target drive torque T0 becomes the point P2 in the region E, the combustion cylinder is reduced by one cylinder and the ignition timing is retarded to the maximum. Thus, the state where the engine output torque is the lowest in the region B is realized, and the remaining torque reduction shortage is achieved by changing the speed ratio of the continuously variable transmission (arrow A), or the combustion cylinder is changed. By reducing the number of cylinders and not performing the retard control of the ignition timing, the engine output torque in the region C is maximized, and the excessive torque reduction is increased by the gear ratio control of the continuously variable transmission. (Arrow c).

The same applies to the case where the engine output torque for realizing the torque reduction to the target drive torque T0 belongs to the region F or the region G. By controlling the speed ratio of the continuously variable transmission, only these engine controls can be used. It interpolates the areas that cannot be achieved.

Thus, no matter what value the target driving torque T0 is set, it is possible to accurately and steplessly reduce the torque to the value T0,
As a result, the understeer state of the vehicle is always effectively eliminated by reducing the vehicle driving torque according to the degree.

When the above-described engine control and the speed ratio control are used together, a change in the vehicle drive torque due to these controls occurs simultaneously, so that the response delay time of the engine control is taken into consideration. The engine control is started first, and thereafter, the gear ratio control is started.
As a result, an unstable torque change in which the vehicle driving torque is reduced in two stages, or once increased and then reduced, or once decreased and then increased is prevented, and is smoothly reduced to the target driving torque T0. become.

In the cold state, similar control is performed using the torque-down characteristic map for each intermediate throttle opening degree shown in FIG. 13 or the same, but in this case, the characteristic shown in FIG. Regions E ', F', and G 'between B', C ', and D' are all interpolated by the speed ratio control of the continuously variable transmission.

When the operating state of the engine belongs to the first inoperable regions X and X 'shown in FIGS. 12 and 13 by the torque down control as described above, the speed ratio of the continuously variable transmission is changed. Is shifted down to increase the engine speed, thereby avoiding operation in these regions X and X '. This prevents occurrence of engine stall during the understeer elimination control. Further, when it belongs to the second non-operable region Y, Y ', the operation in this region Y, Y' is performed by shifting up the speed ratio of the continuously variable transmission to lower the engine speed. To avoid. Thereby, early deterioration of the catalyst device is prevented.

Next, the control when the attitude control for eliminating the understeer state as described above is completed, particularly the gear ratio when the gear ratio control for reducing the vehicle driving torque or avoiding the inoperable region is performed. Will be described.

This control is performed according to the flowchart shown in FIG. 14. First, in step S41, the deviation Δψ of the actual yaw rate に 対 す る from the target yaw rate ψ0 is set to a predetermined value Δψ.
It is determined whether or not the value has become smaller than 1. If it has become smaller, it is further determined in step S42 whether or not the target change amount ΔR of the speed ratio R for eliminating the understeer state has become smaller than a predetermined value ΔR1.

When the target change amount ΔR becomes smaller than the predetermined value ΔR1, in other words, when the understeer state is almost eliminated, the posture control for eliminating the understeer state shown in the flowchart of FIG. To end.

When the deviation Δψ is not smaller than the predetermined value Δψ1, and when the target change amount ΔR
Is not smaller than the predetermined value ΔR1, even when the steering operation by the driver is detected in step S44, or when the depression operation of the accelerator pedal by the driver is detected in step S45, At the same time as when the understeer state is eliminated, the posture control is ended in step S43.

Then, when the gear ratio of the continuously variable transmission is changed from the gear ratio on the gear characteristic previously set in accordance with the operation state shown in FIG. Control for returning to the above gear ratio is performed.

That is, in step S46, it is first determined whether or not the traveling state has shifted to the straight traveling state. If the vehicle is still in a turning state, in step S47, the actual speed ratio R of the continuously variable transmission is determined based on the transmission characteristics. It is determined whether or not the speed ratio R0 is within a predetermined range. When the actual gear ratio R substantially matches the gear ratio R0 on the gear characteristic and is within the above-mentioned predetermined range, control for returning the gear ratio R to the gear ratio R0 on the gear characteristic is performed in step S48. Do. As a result, after the attitude control is completed, the speed ratio of the continuously variable transmission is returned to the speed ratio based on the speed change characteristics without a large change, and a smooth transition to a normal running state is achieved. Become.

On the other hand, at the time when the attitude control is completed, the traveling state is in the straight traveling state, or while the actual speed ratio R is within the predetermined range with respect to the speed ratio R0 in the speed change characteristic. When the traveling state shifts to the straight traveling state, steps S46 to S49 are executed to immediately return to the gear ratio R0 in the gear characteristic without waiting for the gear ratio R to fall within the predetermined range. Let it.

Thus, even if the speed ratio is changed to some extent, the running state becomes unstable and there is no risk of returning to the understeer state. Is prevented from continuing running at a different speed ratio, and the vehicle quickly returns to a normal running state with a speed ratio having a speed characteristic suitable for the driving state.

In this case, since the speed ratio may change to some extent, the operation of returning the speed ratio in step S49 accompanying the shift to the straight traveling state is performed gradually so that the occupant does not feel uncomfortable. It is planned.

FIGS. 15 to 17 show other control examples for restoring the gear ratio to the gear ratio in the gear characteristic, respectively. These control examples will be sequentially described below. The omitted parts of these flowcharts correspond to steps S41, S42, S4 in the flowchart of FIG.
5. Same as S46.

First, the second flowchart shown in FIG.
In the control example, if the attitude control is terminated in step S43a based on the elimination of the understeer state or the driver's steering operation or depressing operation of the accelerator pedal, then in step S46a, the gear ratio R of the continuously variable transmission is changed. It is determined whether or not returning to the characteristic gear ratio R0 results in an upshift.

If it is not possible to shift up,
Next, step S47a is executed to determine whether or not the actual speed ratio R of the continuously variable transmission falls within a predetermined range with respect to the speed ratio R0 on the speed change characteristics. When the speed ratio falls within the predetermined range, the gear ratio R is returned to the gear ratio R0 in the gear characteristic in step S48a. As a result, after the attitude control is completed, the speed ratio of the continuously variable transmission is returned to the speed ratio based on the speed change characteristics without a large change, and a smooth transition to a normal running state is achieved. Become.

On the other hand, the actual speed ratio R is changed to the speed ratio R
When returning to 0 shifts up, the gear ratio on the speed characteristic is immediately determined in step S49a without waiting for the actual gear ratio R to fall within a predetermined range with respect to the gear ratio R0 on the speed characteristic. Return to R0.

As a result, even if the gear ratio is largely changed to a certain extent, the return to the upshift side where there is no risk of the running state becoming unstable or returning to the understeer state again is delayed without delay. Continuation of traveling at a speed ratio different from the speed ratio is avoided, and the vehicle immediately shifts to a normal traveling state with a speed ratio having a speed characteristic suitable for the driving state. In that case, this step S
The point that the gear ratio return operation by 49a is gradually performed is as follows.
This is the same as the control example in FIG.

Next, the third flowchart shown in FIG.
The control example will be described. As in the above control examples, if the attitude control is ended in step S43b due to the elimination of the understeer state or the like, then in step S46b, the throttle opening of the engine at that time is fully closed. or not,
Alternatively, it is determined whether or not the position is completely closed after the end of the posture control.

If it is not fully closed, then step S
Step 47b is executed to determine whether or not the actual speed ratio R of the continuously variable transmission falls within a predetermined range with respect to the speed ratio R0 in the speed change characteristic. The gear ratio is returned to the gear ratio R0 on the gear characteristics. As a result, after the attitude control is completed, the speed ratio of the continuously variable transmission is returned to the speed ratio in the speed change characteristic without a large change, and the state smoothly shifts to the normal running state. .

On the other hand, the throttle opening is fully closed at the end of the attitude control, or fully closed before the actual speed ratio R falls within a predetermined range with respect to the speed ratio R0 in the speed change characteristics. In this case, without waiting for the gear ratio to fall within the predetermined range, the gear ratio is immediately returned to the gear ratio R0 in step S49b.

Thus, when the throttle is fully closed, there is no danger that the running state will become unstable even if the gear ratio is changed to some extent, or that the vehicle will return to the understeer state again. It is avoided to continue running at a speed ratio different from the speed ratio on the characteristic,
The shift to the normal running state with the speed ratio on the speed change characteristic adapted to the driving state is promptly made. In this case, the point that the gear ratio return operation in step S49b is gradually performed is the same as in the above-described control examples.

Next, a fourth control example shown in the flowchart of FIG. 17 will be described.
Step S43c is performed by eliminating the understeer state or the like.
When the attitude control is completed in step S46c, it is then determined in step S46c whether or not the accelerator pedal is depressed by the driver.

If it is not depressed, step S47c is executed to determine whether or not the actual speed ratio R of the continuously variable transmission falls within a predetermined range with respect to the speed ratio R0 on the speed change characteristics. If it is within the predetermined range, step S48
At step c, the gear ratio R is returned to the gear ratio R0 on the gear characteristics. As a result, similarly to the above control examples, after the attitude control is completed, the speed ratio of the continuously variable transmission is returned to the speed ratio based on the speed characteristics without a large change, and the normal traveling state is obtained. Will transition smoothly.

On the other hand, if the driver depresses the accelerator pedal until the actual gear ratio R falls within a predetermined range with respect to the gear ratio R0 in the gear shift characteristic after the end of the attitude control, the actual gear ratio R Without waiting for R to fall within the predetermined range R0, the gear ratio is returned to the gear ratio R0 in the gear shift characteristic. In this case, first, in step S49c, the gear ratio is reduced by a predetermined amount in the downshift direction by this return operation. ΔR2
It is determined whether or not it changes beyond.

If the change in the gear ratio R in the downshift direction exceeds the predetermined amount ΔR2, the return to the gear ratio R0 in the gear characteristic is stopped, and the above-mentioned step S47 is performed.
In step c, the process waits until the actual speed ratio R falls within a predetermined range with respect to the speed ratio R0 in the speed change characteristics. This is because, even when the driver requests acceleration, if the gear ratio greatly changes in the downshift direction, an understeer state may occur again due to an increase in drive torque.

On the other hand, when the gear ratio R is returned to the gear ratio R0 on the gear characteristic, if the gear ratio R does not change beyond the predetermined amount ΔR2 in the downshift direction, Without waiting for the actual speed ratio R to fall within a predetermined range with respect to the speed ratio R0 in the speed change characteristics, step S50 is executed.
At c, the gear ratio is returned to the gear ratio R0 on the gear characteristics.

As a result, when an acceleration request is made by the driver, the request is prioritized, and the driver immediately shifts to a running state with a gear ratio suitable for the operating state in the shift characteristic, whereby the acceleration request is satisfied. Become. In this case, the point that the operation of resetting the gear ratio in step S50c is performed gradually is the same as in the above-described control examples.

[0115]

As described above, according to the present invention, an attitude control device for controlling the attitude of the vehicle in the yawing direction at the time of turning by engine output control and braking force control, and a gear ratio characteristic in which a gear ratio is set in advance. In a vehicle equipped with a continuously variable transmission that can be changed steplessly according to the following, when an understeer state equal to or more than a predetermined state occurs during turning, the vehicle is controlled by the engine output reduction control and the speed ratio control of the continuously variable transmission. Driving torque or vehicle speed is reduced, which makes driving conditions unstable due to excessive use of brake control,
The understeer state is effectively avoided or eliminated without causing deterioration of the re-acceleration performance after the understeer state is eliminated.

According to the present invention, when the speed ratio of the continuously variable transmission is returned to the speed ratio based on the speed characteristics after the understeer state is resolved, the actual speed ratio is changed from the speed ratio based on the speed characteristics. The vehicle is returned when it falls within the predetermined range, thereby avoiding problems such as instability of the running state due to a large change in the gear ratio and re-generation of the understeer state due to an increase in the driving torque. Thus, the state smoothly shifts to the normal running state.

In this case, according to the second to fourth aspects of the invention, when the traveling state shifts to the straight traveling state, when the return of the gear ratio is in the upshifting direction, and when the throttle opening of the engine is fully closed. In such a case, when the above-described problem does not occur even if the gear ratio is immediately restored, the gear ratio is immediately restored to the gear ratio in the gear characteristic without waiting for the actual gear ratio to fall within the predetermined range. Will be. As a result, after the understeer state is resolved, the vehicle is prevented from running at an improper gear ratio, and the vehicle immediately shifts to the normal running state.

According to the fifth aspect of the present invention, when the accelerator pedal is depressed after the understeer state is resolved, the speed ratio is immediately returned to the speed ratio in the speed change characteristic. The required acceleration can be obtained accordingly.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a control system according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a continuously variable transmission used in the embodiment.

FIG. 3 is a shift control map of the continuously variable transmission.

FIG. 4 is a flowchart illustrating a main routine of a control operation according to the embodiment of the present invention.

FIG. 5 is a flowchart showing a subroutine.

FIG. 6 is a map of a first torque down amount used in this subroutine.

FIG. 7 is also a map of a second torque reduction amount.

FIG. 8 is also an engine output map.

FIG. 9 is also a map of a base value of a speed ratio allowable change amount.

FIG. 10 is also a map of a first correction coefficient.

FIG. 11 is also a map of a second correction coefficient.

FIG. 12 is a torque down map when the engine is warm.

FIG. 13 is a torque down map also in a cold state.

FIG. 14 is a flowchart illustrating a control example of gear ratio control after the end of the understeer state.

FIG. 15 is a flowchart showing a second control example.

FIG. 16 is a flowchart showing a third control example.

FIG. 17 is a flowchart showing a fourth control example.

[Explanation of symbols]

Reference Signs List 10 control unit (control means) 37 engine controller (engine output reducing means) 54 attitude control device 55 transmission control device (speed ratio changing means, speed ratio returning means) 80 continuously variable transmission

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16H 61/02 F16H 61/02 // F16H 59:54 59:54 59:58 59:58 59:74 59 : 74 63:06 63:06 (72) Inventor Hiroshi Sasaki 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda F-term (reference) 3D041 AA03 AA32 AA36 AA48 AA49 AA80 AC19 AD02 AD04 AD10 AD14 AD37 AD50 AD51 AE04 AE06 AE09 AE36 AE43 3G093 AA06 BA01 BA05 BA17 BA24 CA03 CB08 CB09 DA01 DA05 DA06 DB00 DB02 DB07 DB11 DB21 EA08 EA09 EA13 EA13 EB03 EB04 FA10 FA11 FB03 3J552 MA09 NB01 PA34 RB21 V04 V04 VBZV02V04 VD14W

Claims (7)

[Claims] An attitude control device for controlling an attitude of a vehicle in a yawing direction at the time of turning by individually controlling an output of an engine and braking forces of left and right wheels, and a shift based on a shift characteristic set in advance. An integrated control device for a vehicle including a continuously variable transmission capable of changing a ratio steplessly,
Understeer detection means for detecting an understeer state of the vehicle at the time of turning, engine output reduction means for reducing the output of the engine, and gear ratio changing means for changing the gear ratio of the continuously variable transmission from the gear ratio on the gear characteristic, When the understeer state is detected by the understeer detection means, control means for reducing the vehicle drive torque by reducing the engine output by the engine output reduction means and controlling the speed ratio of the continuously variable transmission by the speed ratio changing means,
Determining means for determining the elimination of the understeer state; and when the determination means determines the elimination of the understeer state, the actual speed ratio of the continuously variable transmission falls within a predetermined range with respect to the speed ratio on the speed change characteristic. And a speed ratio resetting means for returning the speed ratio to a speed ratio in a speed change characteristic at a point in time. 2. The gear ratio return means, when the traveling state of the vehicle shifts to a straight traveling state, without waiting for the actual gear ratio to fall within a predetermined range with respect to the gear ratio in the gear characteristic. 2. The integrated control device for a vehicle attitude control device and a continuously variable transmission according to claim 1, wherein the ratio is returned to a speed ratio on a speed change characteristic. 3. The gear ratio return means, wherein when the determination means determines that the understeer state is eliminated, when the return to the gear ratio on the gear characteristic is upshifted, the actual gear ratio is changed on the gear characteristic. 2. The vehicle attitude control device and the continuously variable transmission according to claim 1, wherein the speed ratio is returned to a speed ratio based on speed characteristics without waiting for the speed ratio to fall within a predetermined range. Integrated control device. 4. The speed ratio return means, wherein when the determination means determines that the understeer state has been eliminated, when the throttle opening of the engine is fully closed, the actual speed ratio is higher than the speed ratio on the speed characteristics. 2. The attitude control device for a vehicle and the integrated control device for a continuously variable transmission according to claim 1, wherein the actual speed ratio is returned to a speed ratio on the speed change characteristic without waiting for the speed ratio to fall within a predetermined range. . 5. The speed ratio return means, wherein when the accelerator pedal is depressed after the determination means determines that the understeer state has been eliminated, the actual speed ratio falls within a predetermined range with respect to the speed ratio in the speed characteristics. 2. The integrated control device for a vehicle attitude control device and a continuously variable transmission according to claim 1, wherein the speed ratio is returned to a speed ratio on a speed change characteristic without waiting. 6. The speed ratio return means, when the speed ratio is returned to a speed ratio in accordance with the speed characteristics by depressing an accelerator pedal, when the return causes the speed ratio to change in a downshift direction by a predetermined amount or more. 6. The integrated control device for a vehicle attitude control device and the continuously variable transmission according to claim 5, wherein the change is suppressed. 7. The speed ratio resetting means for returning the speed ratio to the speed ratio according to the speed characteristics without waiting for the actual speed ratio to fall within a predetermined range with respect to the speed ratio according to the speed characteristics. 6. The integrated control device for a vehicle attitude control device and the continuously variable transmission according to claim 2, wherein the return is performed gradually.