JP2003200752A - Constant speed running control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate uncomfortable feeling of the change of car speed due to overshoot or undershoot of an actual car speed when a desired car speed is changed with an acceleration by a switch during constant speed running. <P>SOLUTION: A vehicle is accelerated by turning ON an accelerator regime switch 21 until t1, the accelerator regime switch 21 is turned OFF at t1, and a constant speed running control using the car speed at this time as new desired car speed tVSP is restarted. During acceleration between t1 and t2 when car speed aVSP approaches a desired overshoot car speed tVover derived by adding car speed overshoot estimated value tVoffset to the desired car speed aVSP, and during deceleration between t2 and t3 when the car speed aVSP approaches the desired car speed tVSP, a car speed command value cVSP is determined so as to change the actual car speed aVSP by a response causing no un-natural car speed change, and a driving force of the vehicle is controlled so as to achieve this. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant speed running control system for a vehicle, and more particularly, to an actual vehicle speed which can be converged to a newly set changed target vehicle speed after acceleration / deceleration of the vehicle by an acceleration / deceleration switch without any discomfort. The present invention relates to an improvement proposal of a constant speed traveling control device.

[0002]

2. Description of the Related Art A constant speed traveling control device is generally disclosed in, for example, Japanese Unexamined Patent Publication No. 10-30467.
It is usual that the driver controls the driving force of the vehicle so that the target vehicle speed is maintained with the actual vehicle speed when the driver commands the start of the constant speed traveling control by the set coast switch.

Further, when the driver desires to decelerate during constant-speed traveling by the constant-speed traveling control, the driver can decelerate the vehicle by operating the set coast switch, and during constant-speed traveling control. When accelerating is desired, the driver can accelerate the vehicle by operating the accelerator / resume switch.

Then, when the vehicle speed reaches a desired vehicle speed due to acceleration / deceleration by operating an acceleration / deceleration switch such as an accelerator / resume switch or a set / coast switch, the operation is stopped, and then the constant speed traveling control device operates at this time. The constant vehicle speed control can be restarted based on the changed target vehicle speed by setting the actual vehicle speed as the new target vehicle speed. The accelerator / resume switch described above is also used when it is desired to restart the constant speed running control after the constant speed running control is released due to braking by depressing the brake pedal.
By pressing the resume switch, the constant speed traveling control is restarted and the actual vehicle speed can be returned to the target vehicle speed before the control is released.

By the way, in the constant speed running control after the accelerator / resume switch or the set / coast switch is operated to accelerate or decelerate the vehicle as described above, the actual vehicle speed is temporarily changed immediately after the operation of the switch is finished. There is an offset in vehicle speed called overshoot or undershoot that passes through the target vehicle speed, and when this offset amount is large, the vehicle speed deviation between the actual vehicle speed and the target vehicle speed within each control cycle also becomes large, which causes A natural change in vehicle speed occurs and gives an occupant a strange feeling. Figure
More specifically, when the acceleration control by the accelerator / resume switch is stopped at the instant t1, the actual vehicle speed aVSP at the instant t1 is set as the target vehicle speed tVSP, and the constant speed traveling control based on this target vehicle speed is restarted. , The target vehicle speed t after the actual vehicle speed aVSP is once changed immediately after the end of the instant t1
Passing through VSP, an overshoot of vehicle speed with offset amount Voffset occurs. In addition, the set up to the instant t1
If the deceleration control by coast switch is used, the actual vehicle speed
Since aVSP falls below the changed target vehicle speed tVSP, vehicle speed undershoot occurs.

From the viewpoint that the vehicle speed offset such as the overshoot or undershoot is caused by a response delay in a constant speed traveling control system for constant speed traveling control, for example, the above-mentioned Japanese Patent Laid-Open No. 10-30467. As described in (1), there is proposed a technique of compensating for the response delay and suppressing the vehicle speed offset itself.

[0007]

However, the offset amount of the vehicle speed when the constant speed traveling control is restarted due to stopping the acceleration / deceleration by the acceleration / deceleration switch is due to the response delay in the constant speed traveling control system for constant speed traveling. Not only due to this, but also greatly depending on the acceleration / deceleration of the vehicle at that moment and the traveling condition such as the road gradient, the above-mentioned conventional measures cannot suppress the vehicle speed offset which becomes large due to these causes.

According to the present invention, the actual vehicle speed is given a predetermined response when the constant speed traveling control is restarted so as not to cause an unnatural change in the vehicle speed even when the vehicle speed offset amount becomes large depending on the traveling condition of the vehicle. It is an object of the present invention to propose a constant speed traveling control device that solves the above-mentioned problems by adding a transient control for making the target vehicle speed after the change.

[0009]

To this end, according to the present invention, in a constant speed traveling control device of the above-mentioned type, a driver operates an acceleration / deceleration switch during constant speed traveling control as set forth in claim 1. After that, by stopping this operation, the actual vehicle speed is changed in the corresponding direction, and when the constant speed running control is restarted with the actual vehicle speed at the end of the switch operation as the new target vehicle speed, the actual vehicle speed for the changed target vehicle speed Estimate the vehicle speed offset amount of the vehicle speed from the vehicle operating conditions, add this vehicle speed offset amount to the target vehicle speed after the change, and the target vehicle speed after the change is passed through the target vehicle speed offset value that is obtained. It is characterized in that it is configured such that a vehicle speed command value is obtained every moment in order to make the vehicle go toward the vehicle, and the driving force of the vehicle is controlled so that this vehicle speed command value is achieved one by one.

When the vehicle speed offset amount is estimated, it is preferable that the vehicle speed offset amount is estimated from the acceleration of the vehicle at the end of the operation of the acceleration / deceleration switch.

When estimating the vehicle speed offset amount, it is preferable that the estimation is performed from the road surface gradient at the end of the operation of the acceleration / deceleration switch.

The above-mentioned predetermined response is as described in claim 4, while the actual speed ratio approaches the target vehicle speed offset value,
It is preferable that the actual gear ratio is different while the target vehicle speed is changed.

It is preferable that the predetermined response is determined according to the vehicle speed offset amount.

[0014]

According to the first aspect of the present invention, when the constant speed traveling control is restarted after the acceleration / deceleration of the vehicle by the acceleration / deceleration switch, the vehicle speed offset amount of the actual vehicle speed with respect to the changed target vehicle speed is used for the vehicle operation. Estimated from the conditions and adding the vehicle speed offset amount to the changed target vehicle speed to obtain the target vehicle speed offset value obtained via the target vehicle speed offset value. The vehicle speed command value is calculated and the driving force of the vehicle is controlled so that this vehicle speed command value is achieved each time.Therefore, when the actual vehicle speed goes toward the changed target vehicle speed via the target vehicle speed offset value, the vehicle speed is ensured. Therefore, even if the vehicle speed offset amount increases depending on the driving conditions of the vehicle, the vehicle speed change may be unnatural depending on how the predetermined response is given. Can be stopped, it can solve the problem with unnatural vehicle speed change described above.

According to the second aspect of the present invention, when estimating the vehicle speed offset amount, the vehicle speed offset amount is estimated from the acceleration (negative value is a deceleration) of the vehicle at the end of the operation of the acceleration / deceleration switch. The above effects can be reliably achieved regardless of the vehicle acceleration that greatly affects the quantity.

According to the third aspect of the present invention, when the vehicle speed offset amount is estimated, the estimation is performed from the road surface gradient at the end of the operation of the acceleration / deceleration switch. Therefore, the road surface gradient that greatly affects the vehicle speed offset amount. Regardless of the above, it is possible to surely achieve the above-mentioned effects.

According to the fourth aspect of the present invention, the above-mentioned predetermined response is made different between the time when the actual speed ratio approaches the target vehicle speed offset value and the time when the actual speed ratio approaches the changed target vehicle speed. Therefore, it is possible to perform tuning by clearly separating them without affecting each other, and unnatural changes in the vehicle speed while the actual gear ratio approaches the target vehicle speed offset value and after the actual gear ratio is changed. It is possible to reliably eliminate the unnatural change in the vehicle speed while approaching the target vehicle speed.

According to the fifth aspect of the present invention, the predetermined response is determined according to the vehicle speed offset amount, so that it is possible to provide an appropriate vehicle speed change according to the vehicle speed offset amount, Even if the offset amount is large, it is possible to reliably achieve the above-mentioned effects, and avoid the problem that the vehicle speed change is too slow and the convergence to the target vehicle speed after the change is delayed when the vehicle speed offset amount is small. You can

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a power train of a vehicle equipped with a constant speed traveling control device according to an embodiment of the present invention and a control system thereof, and the power train is an engine.
It consists of 1 and continuously variable transmission 2. Although the engine 1 is an internal combustion engine such as a gasoline engine, its throttle valve 5
Is not mechanically connected to the accelerator pedal 3 operated by the driver, but is separated from these to electronically control the opening of the throttle valve 5 by the throttle actuator 4.

The throttle actuator 4 operates in accordance with a target throttle opening (tTVO) output by the engine controller 14 in response to an engine torque command value cTE, which will be described later, to change the opening of the throttle valve 5 to the target throttle opening. The output of the engine 1 is basically controlled to a value according to the accelerator pedal operation.However, depending on how to give the engine torque command value cTE, it is also controlled by factors other than the accelerator pedal operation. It is possible.

The continuously variable transmission 2 is a well-known V-belt type continuously variable transmission, and includes a primary pulley 7 drivingly connected to an output shaft of the engine 1 via a torque converter 6, and a secondary pulley 8 arranged in alignment therewith. , With a V-belt 9 spanning between these pulleys. Then, the differential gear device 11 is drivingly coupled to the secondary pulley 8 via the final drive gear set 10, and the wheels (not shown) are rotationally driven by these.

In the shifting operation of the continuously variable transmission 2, one of the flanges forming the V-grooves of the primary pulley 7 and the secondary pulley 8 is moved relatively to the other fixed flange. The stroke position of both movable flanges is determined by the primary pulley pressure Ppri and the secondary pulley pressure Psec from the shift control hydraulic circuit 12 by narrowing the V-groove width or conversely increasing the V-groove width. .

The shift control hydraulic circuit 12 includes a step motor 13 as a shift actuator, and a transmission controller 15 drives the step motor 13 to a step position STP corresponding to a gear ratio command value (cRATIO), which will be described later. Transmission 2
It is possible to continuously change the speed so that the actual speed ratio matches the speed ratio command value cRATIO.

The engine torque command value cTE to the engine controller 14 and the gear ratio command value (cRATIO) to the transmission controller 15 are respectively controlled by the vehicle speed controller 16
Will be calculated by the calculation described later. Therefore, the vehicle speed control controller 16 is provided with a signal from the constant speed running control switch (corresponding to the set / coast switch described above) 17 for pushing the constant speed running control according to the present invention to the ON state by the driver. And an engine speed sensor 1 that detects the engine speed aNE from the engine ignition signal
The signal from 8, the signal from the vehicle speed sensor 19 that detects the vehicle speed aVSP from the number of rotations of the wheels, the signal from the brake switch 20 that is turned on when the brake pedal (not shown) is depressed, and the driver Input the signal from the accelerator / resume switch 21 for turning on while accelerating the vehicle during constant speed running control and the signal from the road surface inclination angle sensor 22 that detects the road surface inclination angle θ. To do. As the road surface inclination angle sensor 22, a publicly known one such as that disclosed in JP-A-5-34150 can be used as appropriate.

The vehicle speed control controller 16 reads these input information at regular control intervals by a regular interruption,
Based on these input information, the processing shown in the functional block diagram in FIG. 2 is executed, and the engine torque command value cTE to the engine controller 14 and the gear ratio command value cRATIO to the transmission controller 15 are calculated as follows. Ask for. The engine controller 14 and the transmission controller 15 are respectively
These engine torque command value cTE and gear ratio command value cRA
The shift control of the continuously variable transmission 2 and the throttle opening (output) control of the engine 1 are performed based on TIO, and the constant speed traveling control of the vehicle, which is the object of the present invention, is performed.

However, in the present embodiment, the vehicle speed is increased by operating the accelerator / resume switch 21, and when the desired vehicle speed is reached, the operation of the accelerator / resume switch 21 is stopped so that the vehicle speed at this time becomes a new target vehicle speed. The object is to prevent the vehicle speed change (overshoot) when resuming the constant speed traveling control from becoming unnatural as shown in FIG. However, conversely, the vehicle speed is lowered by operating the constant speed travel control switch (set / coast switch) 17, and when the desired vehicle speed is reached, the operation of switch 17 is stopped, and the vehicle speed at this time is set as a new target vehicle speed. Needless to say, the intended purpose can be achieved by the same method when aiming to prevent unnatural changes in vehicle speed (undershoot) when restarting the high speed traveling control.

As shown in FIG. 2, the vehicle speed control controller 16 includes a constant speed traveling control availability determination unit 30, a vehicle speed command value calculation unit 4
0, a target driving force calculation unit 50, an actual gear ratio calculation unit 60, and a driving force distribution unit 70, and the details thereof will be sequentially described below.

The constant-speed traveling control availability determination unit 30 executes the control program shown in FIG. 3 to determine whether or not the constant-speed traveling control should be performed, and the result is determined as the constant-speed traveling control execution flag fSTA.
Set by RT 1 or 0. In step S1 of FIG. 3, it is checked whether the constant speed running control switch 17 is ON or OFF, and then in step S2 it is checked whether the brake switch 20 is ON or OFF.
The accelerator / resume switch 21 is turned on in step S3.
Check whether the target vehicle speed is being increased due to acceleration or OFF.

[0029] In step S1, the constant speed traveling control switch 17 is turned on.
It is determined that the driver desires constant speed traveling control, and that the brake switch 20 is OFF (non-braking) in step S2, and the accelerator / resume switch 21 is OFF in step S3. While the judgment is being made, the driver wants constant speed running control, and even if the control is performed, there is no problem in non-braking, and the accelerator / resume switch 21 does not accelerate (change the target vehicle speed to increase). Therefore, in step S4, it is determined that the constant speed traveling control should be performed, and the constant speed traveling control execution flag fSTART is set to 1.

However, in step S1, the constant speed traveling control switch 21 is turned off (the driver does not desire constant speed traveling control).
Or the brake switch 20 in step S2
Is ON (during braking), or the driver does not want constant speed running control while it is determined in step S3 that the accelerator / resume switch 21 is accelerating (changing the increase in the target vehicle speed). Even if it is desired, the constant speed traveling control should not be performed because the vehicle is being braked or the target vehicle speed is being changed. Therefore, in step S5, the constant speed traveling control execution flag fSTAR is executed.
Reset T to 0. The constant speed traveling control execution flag fSTART set as described above is supplied to the vehicle speed command value calculation unit 40, and as shown in FIG.
14 and the transmission controller 15 as well.

While the constant speed running control execution flag fSTART is 1, the engine controller 14 and the transmission controller 15 achieve these based on the engine torque command value cTE and the gear ratio command value cRATIO from the vehicle speed control controller 16. Thus, the target throttle opening tTVO to the throttle actuator 4 and the command step position STP to the speed change actuator 13 are determined, and the constant speed traveling control according to the present invention is performed. However, constant speed running control execution flag fSTART
During 0, the throttle opening control of the engine 1 and the shift control of the continuously variable transmission 2 are performed as usual instead of the constant speed traveling control according to the present invention.

The vehicle speed command value calculation unit 40 in FIG. 2 is as shown in detail in FIG. 4, and comprises a target vehicle speed determination unit 41, a transient target vehicle speed offset amount calculation unit 42, and an adder 40a.
The target vehicle speed determination unit 41 receives the actual vehicle speed aVSP and the signal from the accelerator / resume switch 21, and executes the control program shown in FIG. 5 on the basis of these signals to determine the target vehicle speed tVSP to be the target for constant speed traveling control. calculate. Figure 5
First, in step S11, it is determined whether or not the accelerator / resume switch 21 is ON (while the target vehicle speed is being increased by acceleration), and if it is ON, the target vehicle speed is changed in step S12 to indicate that the target vehicle speed is being changed. Vehicle speed set flag
If ftVSPSET is set to 0 and is OFF, in step S13 the target vehicle speed set flag ft is displayed to indicate that the target vehicle speed is not being changed.
Set VSPSET to 1.

In the next step S14, the accelerator / resume switch 21 is set to the previous OF by determining whether the previous value ftVSPSET (Buf) of the target vehicle speed set flag ftVSPSET is 1 or not.
It is determined whether it is F (the target vehicle speed was not being changed last time). If ftVSPSET (Buf) = 1, skip step S15 and step S16 and proceed with the control to step S17.
Here, the previous value ftVSPSET (Buf) of the target vehicle speed set flag is updated by this target vehicle speed set flag ftVSPSET to prepare for the next control.

When it is determined in step S14 that ftVSPSET (Buf) is not 1, that is, the accelerator / resume switch 21
If was previously turned on (the target vehicle speed was being changed last time), depending on whether or not the target vehicle speed set flag ftVSPSET of this time is 1 in step S15, the accelerator / resume switch 21 is turned on.
It is determined whether it has been switched to OFF (whether or not the target vehicle speed change due to acceleration has been completed). When it is determined that the accelerator / resume switch 21 is switched from ON to OFF (the change in the target vehicle speed due to acceleration is completed), the target vehicle speed tVSP is changed to the current actual vehicle speed aVSP in step S16, and the accelerator / resume switch 21 is changed. When it is determined that is still in the ON state (the target vehicle speed change due to acceleration continues), step S16 is skipped and the target vehicle speed tVSP is not changed. After the processing for changing the target vehicle speed tVSP, step S17 is executed to update the previous value ftVSPSET (Buf) of the target vehicle speed set flag with the target vehicle speed set flag ftVSPSET of this time, and prepare for the next control.

The transient target vehicle speed offset amount calculation unit 42 in FIG. 4 is the same as that shown in FIG.
An acceleration equivalent vehicle speed offset amount calculation unit 44, a road surface gradient equivalent vehicle speed offset amount calculation unit 45, a final acceleration equivalent vehicle speed offset amount determination unit 46, and a final road surface gradient equivalent vehicle speed offset amount determination unit 47. Constitute. Acceleration calculation unit 43
Calculates the estimated acceleration value αobs from the actual vehicle speed aVSP detected by the vehicle speed sensor 19 by using the transfer function (constant Kobs, time constant Tobs, Laplace operator S) as shown in FIG. αobs ＝ [(Kobs / Tobs) ・ S {S ² + (1 / Tobs) ・ S + (Kobs / To
bs)}] ・ aVSP Note that, as is generally done, the acceleration estimated value α is calculated with the amount of change in the actual vehicle speed aVSP during the calculation cycle.
It can also be obs.

The acceleration-corresponding vehicle speed offset amount calculation unit 44 in FIG. 6 calculates the acceleration-corresponding vehicle speed offset amount Vof from the estimated acceleration value αobs based on the scheduled map shown in FIG.
Search fsetα. The road surface gradient equivalent vehicle speed offset amount calculation unit 45 in FIG. 6 retrieves the road surface gradient equivalent vehicle speed offset amount Voffsetθ from the road surface gradient θ detected by the road surface inclination angle sensor 22 based on the scheduled map shown in FIG. 10. To do.

The final acceleration-corresponding vehicle speed offset amount determining unit 46 in FIG.
The control program of FIG. 9 is executed based on setα and the accelerator / resume switch (21) signal, and the vehicle speed offset amount Voffsetα corresponding to the acceleration when the target vehicle speed is changed by turning ON / OFF the accelerator / resume switch 21 Is a vehicle speed offset amount Voffset α'corresponding to the final acceleration. Therefore, in FIG. 9, first in step S21, it is determined whether the accelerator / resume switch 21 is ON (during change of the target vehicle speed due to acceleration) or OFF. accelerator·
When the resume switch 21 is ON (changing the target vehicle speed due to acceleration), the vehicle speed offset amount determination flag fVoffsetα corresponding to the final acceleration is set to 0 in step S22 to indicate that the target vehicle speed due to acceleration is being changed. If the accelerator / resume switch 21 is not ON (the target vehicle speed is being changed due to acceleration), the vehicle speed offset amount determination flag fVoffsetα corresponding to the final acceleration is set in step S23.
To indicate that the target vehicle speed due to acceleration is not being changed 1
To

In the next step S24, the previous value fVoffs of the vehicle speed offset amount determination flag fVoffsetα corresponding to the final acceleration is calculated.
Depending on whether etα (Buf) is 1, the previous accelerator /
It is determined whether the resume switch 21 is OFF (while the target vehicle speed is not changing). When fVoffsetα (Buf) = 1,
Step S25 and step S26 are skipped, and the control proceeds to step S27, where the previous value fVoffsetα (Buf) of the final acceleration equivalent vehicle speed offset amount determination flag is set to the current final acceleration equivalent vehicle speed offset amount determination flag fVoffsetα.
To prepare for the next control.

When it is determined in step S24 that fVoffsetα (Buf) is not 1, that is, the accelerator / resume switch
If 21 is previously turned on (the target vehicle speed was being changed last time), the accelerator / resume switch 21 is switched from ON to OFF depending on whether or not the final acceleration-corresponding vehicle speed offset amount determination flag fVoffsetα is 1 in step S25. Whether or not (whether or not the change of the target vehicle speed due to acceleration is completed) is determined. Accelerator / resume switch 2 in step S25
When it is determined that 1 is switched from ON to OFF (the change in the target vehicle speed due to acceleration is completed), the final acceleration-corresponding vehicle speed offset amount Voffsetα 'is updated to the acceleration-corresponding vehicle speed offset amount Voffsetα in step S26, and the step If it is determined in S25 that the accelerator / resume switch 21 is still in the ON state (the target vehicle speed change due to acceleration is continuing), step S26 is skipped and the final acceleration-corresponding vehicle speed offset amount Voffsetα ' Make no changes. Therefore, the final acceleration equivalent vehicle speed offset amount Vo
ffsetα 'is ON → O of accelerator / resume switch 21
It is a vehicle speed offset amount Voffsetα corresponding to the acceleration when the target vehicle speed is changed by FF. After the final acceleration equivalent vehicle speed offset amount Voffsetα 'is determined, step S27 is executed to set the previous value fVoffsetα (Buf) of the final acceleration equivalent vehicle speed offset amount determination flag to the current final acceleration equivalent vehicle speed offset amount determination flag fVoffsetα. It is updated by and prepared for the next control.

The vehicle speed offset amount determining portion 47 corresponding to the final road surface gradient in FIG.
The control program shown in Fig. 11 is executed based on Voffsetθ and the accelerator / resume switch (21) signal to
Vehicle speed offset amount Voffse corresponding to the road surface slope when the target vehicle speed is changed by turning the resume switch 21 from ON to OFF
tθ is the amount of vehicle speed offset corresponding to the final road gradient Voffsetθ '
It is what This is why in Figure 11, the first step is
In S31, it is determined whether the accelerator / resume switch 21 is ON (changing the target vehicle speed due to acceleration) or OFF. If the accelerator / resume switch 21 is ON (the target vehicle speed is being changed by acceleration), the final road surface slope equivalent minute vehicle speed offset amount determination flag fVoffsetθ is set to 0 in step S32 to indicate that the target vehicle speed is being changed by acceleration. However, if the accelerator / resume switch 21 is not ON (during change of the target vehicle speed due to acceleration), the vehicle speed offset amount determination flag fV corresponding to the final road surface slope is determined in step S33.
The offset θ is set to 1 to indicate that the target vehicle speed due to acceleration is not being changed.

In the next step S34, the previous value fVof of the vehicle speed offset amount determination flag fVoffsetθ corresponding to the final road surface gradient is calculated.
Depending on whether or not fsetθ (Buf) is 1, it is determined whether or not the accelerator / resume switch 21 was OFF (the target vehicle speed is not being changed) last time. If fVoffsetθ (Buf) = 1, skip steps S35 and S36 and proceed with the control to step S37, where the previous value fVoffsetθ (Buf) of the final road surface slope equivalent minute vehicle speed offset amount determination flag is set to the last road surface this time. Gradient equivalent vehicle speed offset amount determination flag fV
It is updated by offset θ to prepare for the next control.

When it is determined in step S34 that fVoffsetθ (Buf) is not 1, that is, the accelerator / resume switch
If 21 is ON last time (the target vehicle speed was being changed last time), the accelerator / accelerator is determined in step S35 depending on whether or not the vehicle speed offset amount determination flag fVoffsetθ for this final road surface gradient is 1 this time.
It is determined whether the resume switch 21 is switched from ON to OFF (whether or not the change of the target vehicle speed due to acceleration is completed). If it is determined in step S35 that the accelerator / resume switch 21 has been switched from ON to OFF (the change in the target vehicle speed due to acceleration is completed), the vehicle speed offset amount Voffset corresponding to the final road surface gradient is calculated in step S36.
θ ′ is updated to the vehicle speed offset amount Voffsetθ that corresponds to the road gradient, and the accelerator / resume switch 21 is updated in step S35.
When it is determined that is still in the ON state (the change of the target vehicle speed due to acceleration continues), step S36 is skipped and the vehicle speed offset amount Voffset corresponding to the final road surface gradient is skipped.
Do not change θ '. Therefore, the vehicle speed offset amount Voffset θ ′ corresponding to the final road surface gradient is the vehicle speed offset amount Voffsetθ corresponding to the road surface gradient when the change of the target vehicle speed is completed by turning ON / OFF the accelerator / resume switch 21.
The vehicle speed offset amount Voffset corresponding to the final road gradient
After the determination of θ ′, step S37 is executed and the previous value fVoffsetθ of the vehicle speed offset amount determination flag corresponding to the final road surface gradient is executed.
(Buf) is updated by the vehicle speed offset amount determination flag fVoffsetθ corresponding to the final road surface gradient this time to prepare for the next control.

The adder 48 in FIG. 6 adds up the vehicle speed offset amount Voffset α'corresponding to the final acceleration and the vehicle speed offset amount Voffset θ'corresponding to the final road surface gradient, and offsets (overshoots) the vehicle speed with respect to the target vehicle speed. And the target vehicle speed offset amount tVoffset (= Voffset
α '+ amount Voffset θ'). This target vehicle speed offset amount tVoffset means a target vehicle speed offset amount indicating how much the target vehicle speed should be offset from the original value in order to match the actual vehicle speed offset amount with respect to the target vehicle speed.

The transient target vehicle speed offset amount determining unit 49 in FIG. 6 includes a target vehicle speed offset amount response characteristic determining unit 49a and a transient target vehicle speed offset amount calculating unit 49b as shown in FIG.
It consists of and. Target vehicle speed offset amount response characteristic determination unit 49
a is a constant speed running control execution flag fSTART, target vehicle speed tVSP,
Based on the actual vehicle speed aVSP and the target vehicle speed offset amount tVoffset, in order to prevent an unnatural vehicle speed change, it is determined which response to perform the vehicle speed offset, and the determined response is switched to the response characteristic. The transition target vehicle speed offset amount calculation unit 49b is instructed by the flag Fres, and the transition target vehicle speed offset amount calculation unit 49b performs the vehicle speed offset with the above response based on the response characteristic switching flag Fres and the target vehicle speed offset amount tVoffset. Target vehicle speed offset amount tVoffset '
Is calculated every moment.

For this reason, the former target vehicle speed offset amount response characteristic determining unit 49a performs the processing shown in FIG. 13, and first in step S41, is the previous value fSTART (Buf) of the constant speed running control execution flag fSTART 1? It is determined whether or not the accelerator / resume switch 21 was previously OFF (during constant-speed running control in which the target vehicle speed was not changed), and whether or not the determination result is S42 and At step S43, the current constant speed running control execution flag fSTART is 1
Depending on whether or not the accelerator / resume switch 21 is
It is determined whether it is OFF or ON (the target vehicle speed has been changed and the constant speed traveling control is suspended). If it is determined in step S41 to step S43 that the accelerator / resume switch 21 is switched from OFF to ON, the response characteristic switching flag Fres is set to 3 for turning the constant speed running control OFF in step S44, and the accelerator / resume switch 21 is set. Is ON
When it is determined that the response characteristic switching flag Fres is for restarting the constant speed traveling control in step S45 (when the accelerator / resume switch 21 is turned ON → OFF at the instant t1 in FIG. 23 under the same conditions as in FIG. 24). Explaining the case, when the vehicle speed aVSP is set to 1 for increasing the target overshoot vehicle speed tVover described later) and it is determined that the accelerator / resume switch 21 is kept ON, the response characteristic is determined in step S46. If the switching flag Fres is set to 3 for turning off the constant speed traveling control, and if it is determined that the accelerator / resume switch 21 remains off, steps S44 to S46 are skipped and the response characteristic switching flag at these steps is set. Do not execute Fres setting.

After the above processing, the control advances to step S47, where it is checked whether or not the response characteristic switching flag Fres is set to 1 for restarting the constant speed traveling control. Fres
If = 1, in step S48, the vehicle speed deviation | aVSP-tVover | V
Whether or not the actual vehicle speed aVSP has sufficiently approached the target overshoot vehicle speed tVover (reached the instant t2 in FIG. 23) is determined depending on whether it is less than l. When approaching, in step S49, the response characteristic switching flag Fres is set for after restarting the constant speed traveling control (the vehicle speed aVSP is set to the target overshoot vehicle speed tVo after the instant t2
Set to 2) for decreasing from ver to target vehicle speed tVSP).

In step S47, the response characteristic switching flag Fre
When it is determined that s is not 1 for restarting the constant speed traveling control,
In step S50, it is checked whether Fres = 2 or Fres = 3. If Fres = 2, in step S51 the vehicle speed aVSP and the target vehicle speed tVSP
Between vehicle speed deviation | aVSP-tVSP |
Whether or not the actual vehicle speed aVSP is sufficiently close to the target vehicle speed tVSP as at the instant t3 in FIG. 23 is determined depending on whether or not it is less than 2. When approaching, in step S52, response characteristic switching flag F
res is set to 3 (constant speed control O
Same as for FF). If it is determined in step S50 that Fres = 3 or in step S51 that the actual vehicle speed aVSP is sufficiently close to the target vehicle speed tVSP, the response characteristic switching flag is set.
Do not change Fres. After setting the response characteristic switching flag Fres as described above, in step S54, the previous value fSTART (Buf) of the constant speed traveling control execution flag is updated by the current constant speed traveling control execution flag fSTART to contribute to the next control. .

The transient target vehicle speed offset amount calculation unit 49b in FIG. 12 is as shown in FIG. 14, and includes a transient target vehicle speed offset amount calculation unit 49b-1 during acceleration control and a transient target vehicle speed offset amount calculation unit 49b- during deceleration control. 2, a transient target vehicle speed offset amount calculation unit 49b-3 during steady constant speed traveling control, and a transient target vehicle speed offset amount selection unit 49b-4.

The transient target vehicle speed offset amount calculating section 49b-1 during acceleration control has a vehicle speed command value cVSP that smoothly changes the vehicle speed aVSP during the acceleration control between the instants t1 and t2 in FIG. 23 as shown by the solid line. The transient target vehicle speed offset amount tVoffset1 at the time of acceleration control for giving is obtained based on the target vehicle speed offset amount tVoffset. For example, a configuration as shown in FIG. 15 can be adopted. The acceleration control transient target vehicle speed offset amount calculation unit 49b-1 in FIG. 15 is an acceleration control low pass filter unit 49b-1a.
And an acceleration control time constant calculation unit 49b-1b. The acceleration control time constant calculation unit 49b-1b uses the scheduled map illustrated in FIG. 16 to set the target vehicle speed offset amount tVoffset.
The time constant Tover for acceleration control is obtained by searching from. The acceleration control low-pass filter section 49b-1a receives the target vehicle speed offset amount tVoffset as an input and uses the acceleration control time constant described above.
A transient target vehicle speed offset amount during acceleration control tV
Calculate offsetl.

[Equation 1]

The deceleration control transient target vehicle speed offset amount calculation unit 49b-2 in FIG. 14 is a vehicle speed command for smoothly changing the vehicle speed aVSP during deceleration control between the instants t2 and t3 in FIG. 23 as shown by the solid line, for example. The transient target vehicle speed offset amount tVoffset2 at the time of deceleration control for giving the value cVSP is obtained based on the target vehicle speed offset amount tVoffset. For example, a configuration as shown in FIG. 17 can be adopted. The deceleration control transient target vehicle speed offset amount calculation unit 49b-2 in FIG. 17 includes a deceleration control low pass filter unit 49b-2a and a deceleration control time constant calculation unit 49b-2b. The deceleration control time constant calculation unit 49b-2b obtains the deceleration control time constant Tsd from the target vehicle speed offset amount tVoffset by using a scheduled map as illustrated in FIG. The deceleration control low-pass filter unit 49b-2a receives the target vehicle speed offset amount tVoffset as an input, and uses the first-order lag low-pass filter as shown in the following equation using the deceleration control time constant Tsd to perform deceleration control. The time transient target vehicle speed offset amount tVoffset2 is calculated.

[Equation 2]

The transient target vehicle speed offset amount calculating section 49b-3 in the steady constant speed running control shown in FIG. 14 is used in the steady constant speed running control after the instant t3 in FIG. The vehicle speed offset amount tVoffset3 is calculated by the following formula. tVoffset3 = 0 Here, tVoffset3 = 0 means that the transient control is not performed during the steady constant-speed running control after the instant t3 in FIG.

The transient target vehicle speed offset amount selection unit 49b-4 in FIG. 14 performs the processing of FIG. 19 based on the response characteristic switching flag Fres when Fres = 1 (the instants t1 to t2 in FIG. 23).
During acceleration control), the transient target vehicle speed offset amount tVoffsetl during acceleration control is set to the transient target vehicle speed offset amount tVoffse
It is output as t ', and when Fres = 2 (the instants t2 to t3 in FIG. 23).
During deceleration control), the transient target vehicle speed offset amount tVoffset2 during deceleration control is set to the transient target vehicle speed offset amount tVoffse
output as t ', and when Fres = 3 (during steady constant speed running control after the instant t3 in FIG. 23), the transient target vehicle speed offset amount tVoffset3 during steady constant speed running control is set as the transient target vehicle speed offset amount tVoffset'. Output.

The transient target vehicle speed offset amount tVoffset 'obtained as described above is added to the target vehicle speed tVSP by the adder 40a in FIG. 4 to be used for calculation of the vehicle speed command value cVSP. 2 is supplied from the vehicle speed command value calculation unit 40 to the target driving force calculation unit 50 in FIG. The target driving force calculation unit 50 obtains the target driving force For 'for achieving the vehicle speed command value cVSP.For example, as shown in FIG. 20, since the control system is strong against the disturbance such as the road surface gradient fluctuation, the disturbance estimator is used. The robust compensator 51 is a robust compensator 51, and the model matching compensator 52 is a model matching compensator having the response characteristic of the reference model as the overall response characteristic.

The robust compensator 51 constitutes a control system for matching actual characteristics with a vehicle linear model (Gv (s)) by estimating and correcting disturbances such as modeling error of the controlled object and running resistance. You can H (s) is a robust filter that determines the disturbance rejection performance, and is, for example, as in the following equation.

[Equation 3]

The model matching compensator 52 uses the reference model R ₂ (s) of the feedback control section (FF section) to determine the input / output response characteristics, and the feedback control section (FB section).
The disturbance rejection performance and stability are respectively determined by the reference model R _l (s) of, and thus a low-pass filter with a first-order delay is used, for example, as in the following equation.

[Equation 4]

[Equation 5]

Linear approximation model Gv of vehicle to be controlled
(S) is the integral characteristic and is given by the following equation.

[Equation 6] From the above, the target driving force For 'and the estimated disturbance value dv' can be obtained as follows.

[Equation 7]

[Equation 8]

[Equation 9]

The actual gear ratio calculating section 60 in FIG.
From the aVSP and the engine speed aNE input from the engine speed sensor 18, the actual gear ratio aRATIO is calculated according to the following equation.

[Equation 10] The calculated actual gear ratio aRATIO is supplied to the driving force distribution unit 70.

As shown in FIG. 21, the driving force distribution unit 70 in FIG. 2 comprises a driving torque command value calculation unit 71, a gear ratio command value setting unit 72, and an engine torque command value calculation unit 73. Own vehicle speed aVSP, target driving force For 'and actual gear ratio aRATI
Based on O, the gear ratio command value cRATIO and the engine torque command value cTE for achieving the target driving force For 'are determined and output. The drive torque command value calculation unit 71 calculates the target drive force.
The drive torque command value c corresponding to this from For 'according to the following equation
Calculate TDR. cTDR = FOR '× Rt Rt: Tire radius

The gear ratio command value setting unit 71 calculates the gear ratio command value cRATIO from the own vehicle speed aVSP and the drive torque command value cTDR based on the map showing the relationship between the vehicle speed and drive torque and the gear ratio illustrated in FIG. To set. 22. Here, FIG. 22 shows a map when a continuously variable transmission is used. As is clear from FIG. 22, the gear ratio command value cRATIO is set to increase as the drive torque command value cTDR increases, and when the drive torque command value cTDR is the same, the gear ratio command value increases as the vehicle speed increases. cRATIO is set to be small.

Engine torque command value calculation unit in FIG. 21
72 calculates the engine torque command value cTE from the drive torque command value cTDR and the actual gear ratio aRATIO according to the following equation.

[Equation 11]

Engine torque command value obtained by the above equation
cTE is input to the engine controller 14 (see FIGS. 1 and 2), and the engine controller 14 outputs to the throttle actuator 4 the target throttle opening tTVO corresponding to the engine torque command value cTE. On the other hand, the gear ratio command value cRATIO is input to the transmission controller 15 (see FIGS. 1 and 2), and the transmission controller 15 outputs the command step position STP corresponding to the gear ratio command value cRATIO to the gear shift actuator 13. To do. It is possible to achieve the above-described target driving force For ′ by the engine output control and the shift control based on the target throttle opening degree tTVO and the command step position STP, and to realize the constant speed traveling control which is the target of the present invention.

By the way, according to the present embodiment, the accelerator / resume switch 21 is set at the instant t1 in FIG.
When the constant speed traveling control is restarted after the vehicle is accelerated by, the vehicle speed offset amount tVoffset of the actual vehicle speed aVSP with respect to the changed target vehicle speed tVSP is estimated from the vehicle operating conditions (estimated acceleration value αobs and road gradient θ), and this vehicle speed offset Quantity t
Target vehicle speed offset value obtained by adding Voffset to the changed target vehicle speed tVSP (target overshoot vehicle speed tVover)
Figure 23 shows the actual vehicle speed aVSP to the target vehicle speed tVSP after change via
The vehicle speed command value cVSP is calculated to obtain a predetermined response as indicated by the solid line, and the driving force of the vehicle is controlled so that this vehicle speed command value cVSP is achieved. Can reliably change the vehicle speed with the above-mentioned predetermined response when moving toward the changed target vehicle speed via the target vehicle speed offset value, and even when the vehicle speed offset amount tVoffset becomes large as shown in FIG. 23 depending on the running condition of the vehicle. , Figure the vehicle speed aVSP depending on how the above given response is given
The change tendency shown in FIG. 24 can be changed to the smooth change tendency shown in FIG. 23, and it is possible to prevent the vehicle speed change from becoming unnatural as shown in FIG. 24 and eliminate discomfort. .

According to the present embodiment, when estimating the vehicle speed offset amount tVoffset, the estimation is performed from the vehicle acceleration (negative deceleration) estimated value αobs and the road surface gradient θ at the end of the operation of the accelerator / resume switch 21. Since this is performed, the above-described operational effects can be reliably achieved regardless of the vehicle acceleration or the road surface gradient that greatly affects the vehicle speed offset amount tVoffset.

Further, the above-mentioned predetermined response is given at the instant t in FIG.
When the actual gear ratio aVSP accelerates toward the target vehicle speed offset value tVover as between 1 and t2, and at the instant t2 in FIG.
Since the actual gear ratio aVSP is individually determined at the time of deceleration toward the target vehicle speed tVSP after the change as in the period of t3, it is possible to perform the tuning separately without clearly affecting each other. An unnatural change in vehicle speed during acceleration in which the actual gear ratio aVSP moves toward the target vehicle speed offset value tVover, and the target vehicle speed tVSP after the actual gear ratio aVSP is changed.
An unnatural change in vehicle speed during deceleration toward the vehicle can be reliably eliminated.

Furthermore, FIG. 16 and FIG.
Since it is determined according to the vehicle speed offset amount tVoffset as illustrated in FIG. 18, it is possible to provide an appropriate vehicle speed change according to the vehicle speed offset amount tVoffset, and reliably achieve the above-described effects even when the vehicle speed offset amount tVoffset is large. In addition, it is possible to avoid the problem that when the vehicle speed offset amount tVoffset is small, the vehicle speed change is unnecessarily slow and the convergence to the changed target vehicle speed tVSP is delayed.

[Brief description of drawings]

FIG. 1 is a schematic system diagram showing a power train of a vehicle equipped with a continuously variable transmission equipped with a constant speed traveling control device according to an embodiment of the present invention together with its control system.

FIG. 2 is a functional block diagram of constant-speed traveling control executed by a controller in the control system of FIG. 1 through a shift control of a continuously variable transmission and an engine throttle opening control.

FIG. 3 is a flowchart showing a control program executed by a constant speed traveling control availability determination unit in FIG. 2 to determine whether or not to perform constant speed traveling control according to the present invention.

FIG. 4 is a functional block diagram showing a vehicle speed command value calculation unit in FIG. 2.

FIG. 5 is a flowchart showing a control program executed by a target vehicle speed determination unit in the vehicle speed command value calculation unit when setting a target vehicle speed.

FIG. 6 is a functional block diagram of a transient target vehicle speed offset amount calculation unit in the vehicle speed command value calculation unit.

FIG. 7 is a functional block diagram of an acceleration calculation unit in the transient target vehicle speed offset amount calculation unit.

8 is a characteristic diagram of the offset amount used by the acceleration-corresponding vehicle speed offset amount calculation unit in FIG. 6 to obtain the acceleration-corresponding vehicle speed offset amount.

FIG. 9 is a flowchart of a control program executed by a final acceleration-equivalent vehicle speed offset amount determination unit in the transient target vehicle speed offset amount calculation unit.

FIG. 10 is a characteristic diagram of an offset amount used by a road surface gradient equivalent vehicle speed offset amount calculation unit in the transient target vehicle speed offset amount calculation unit to obtain a road surface gradient equivalent vehicle speed offset amount.

FIG. 11 is a flowchart of a control program executed by a vehicle speed offset amount determining unit for a final road surface gradient in the transient target vehicle speed offset calculating unit.

FIG. 12 is a functional block diagram of a transient target vehicle speed offset amount determination unit in FIG. 6.

FIG. 13 is a flowchart of a control program executed by a target vehicle speed offset amount response characteristic determination unit in the transient target vehicle speed offset amount determination unit.

FIG. 14 is a functional block diagram of a transient target vehicle speed offset amount calculation unit in the transient target vehicle speed offset amount determination unit.

15 is a functional block diagram of a transient target vehicle speed offset amount calculation unit during acceleration control in FIG.

FIG. 16 is a change characteristic diagram of a time constant used by the transient control target vehicle speed offset amount calculating section during acceleration control to determine a transient target vehicle speed offset amount during acceleration control.

FIG. 17 is a functional block diagram of a transient target vehicle speed offset amount calculation unit during deceleration control in FIG. 14.

FIG. 18 is a change characteristic diagram of the time constant used by the transient target vehicle speed offset amount calculating section during deceleration control to calculate the transient target vehicle speed offset amount during deceleration control.

FIG. 19 is a flowchart of a control program executed by the transient target vehicle speed offset amount selection unit in FIG.

20 is a functional block diagram of the target driving force calculation unit in FIG. 2. FIG.

21 is a functional block diagram of the driving force distributor in FIG. 2. FIG.

FIG. 22 is a characteristic diagram used when a gear ratio command value setting unit in the driving force distribution unit obtains a gear ratio command value.

FIG. 23 is a time chart showing the operation of the constant speed running control device according to the present invention in the case where the constant speed running control is restarted by turning the switch off after accelerating by operating the accelerator / resume switch to change the target vehicle speed. Is.

FIG. 24 is a time chart showing the operation of the conventional device under the same conditions as in FIG. 23.

[Explanation of symbols]

1 Engine 2 Continuously Variable Transmission 3 Accelerator Pedal 4 Throttle Actuator 5 Throttle Valve 6 Torque Converter 7 Primary Pulley 8 Secondary Pulley 9 V Belt 10 Final Drive Gear Set 11 Differential Gear Device 12 Gear Change Control Hydraulic Circuit 13 Step Motor 14 Engine Controller 15 Gear Change Machine controller 16 Controller for vehicle speed control 17 Constant speed travel control switch (deceleration switch) 18 Engine speed sensor 19 Vehicle speed sensor 20 Brake switch 21 Accelerator / resume switch (acceleration switch) 22 Road surface inclination angle sensor 30 Constant speed travel control availability judgment unit 40 Vehicle speed command value calculation unit 41 Target vehicle speed determination unit 42 Transient target vehicle speed offset amount calculation unit 43 Acceleration calculation unit 44 Acceleration equivalent vehicle speed offset amount calculation unit 45 Road surface gradient equivalent vehicle speed offset amount calculation unit 46 Final acceleration equivalent minute vehicle speed offset amount Decision 47 Final road slope equivalent minute vehicle speed offset amount determination unit 48 Adder 49 Transient target vehicle speed offset amount determination unit 49a Target vehicle speed offset amount response characteristic determination unit 49b Transient target vehicle speed offset amount calculation unit 49b-1 Transient target vehicle speed offset amount during acceleration control Calculation unit 49b-2 Transient target vehicle speed offset amount calculation unit during deceleration control Calculation unit 49b-3 Transient target vehicle speed offset amount calculation unit during steady constant speed traveling control 49b-4 Transient target vehicle speed offset amount selection unit 50 Target driving force calculation unit 51 Robust Compensator 52 Model matching compensator 60 Actual gear ratio calculation unit 70 Driving force distribution unit 71 Drive torque command value calculation unit 72 Gear ratio command value setting unit 73 Engine torque command value calculation unit

Continued front page    F-term (reference) 3D044 AA03 AA04 AA14 AA21 AA45                       AB01 AC05 AC15 AC24 AC26                       AC57 AD04 AD17 AE14 AE21                 3G093 AA01 AA05 BA15 BA23 CB11                       CB13 DA01 DA06 DB05 DB15                       DB18 EA02 EA09 EB03 FA04

Claims (5)

[Claims] 1. The constant vehicle speed control is configured such that the actual vehicle speed when the driver gives an instruction to start the constant vehicle speed control is set as a target vehicle speed and the driving force of the vehicle is controlled so that the target vehicle speed is maintained. By stopping the operation after the driver operates the acceleration / deceleration switch while driving at a constant speed, the actual vehicle speed can be changed to the direction corresponding to the direction of the operation, and the actual vehicle speed when the operation is stopped can be changed. In the constant-speed traveling control device that contributes to constant-speed traveling control as a new target vehicle speed, when changing the target vehicle speed accompanying the operation of the acceleration / deceleration switch,
The vehicle speed offset amount of the actual vehicle speed with respect to the changed target vehicle speed is estimated from the vehicle operating conditions, and the changed vehicle speed offset value is added to the changed target vehicle speed to obtain the changed vehicle speed target value. A constant vehicle speed command value is obtained to make the actual vehicle speed approach the vehicle speed with a predetermined response, and the driving force of the vehicle is controlled so that this vehicle speed command value is achieved one by one. Speed control device. 2. The constant speed traveling control device according to claim 1, wherein the vehicle speed offset amount is estimated from the acceleration of the vehicle at the end of the operation of the acceleration / deceleration switch. 3. The constant speed traveling control device according to claim 1, wherein the vehicle speed offset amount is estimated from a road surface gradient at the end of operation of the acceleration / deceleration switch. 4. The predetermined response according to claim 1, wherein the predetermined response is obtained while the actual speed ratio approaches the target vehicle speed offset value and while the actual speed ratio approaches the changed target vehicle speed. A constant speed traveling control device characterized by being different. 5. The constant speed traveling control device according to claim 1, wherein the predetermined response is determined according to the vehicle speed offset amount.