JPH07304349A - Constant-speed running control device for vehicle - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent overshoot of vehicle speed due to a decrease in drive torque during gear shifting. [Composition] Feedback control means 1 for feedback controlling the throttle opening so that the actual vehicle speed matches the target vehicle speed based on the deviation between the actual vehicle speed and the target vehicle speed.
In the vehicle constant speed traveling control device including 0, 34, the feedforward control means 10, 3 for controlling the throttle opening to a predetermined value regardless of the deviation between the actual vehicle speed and the target vehicle speed.
4 and selection means 11 for activating the feedback control means when the automatic transmission is not performing the gear shifting operation and activating the feedforward control means during the gear shifting operation of the automatic transmission.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle constant speed traveling control device for traveling while maintaining an actual vehicle speed of a vehicle at a target vehicle speed set by an occupant.

[0002]

2. Description of the Related Art Conventionally, based on a deviation between a target vehicle speed set according to an operation of an occupant and an actual vehicle speed detected by a vehicle speed sensor, the throttle valve is controlled so that the actual vehicle speed matches the target vehicle speed. 2. Description of the Related Art There is known a vehicle constant speed traveling control device that feedback-controls an opening (hereinafter, throttle opening).

In particular, in the constant speed traveling control device disclosed in Japanese Patent Laid-Open No. 57-119137, in addition to the above speed deviation,
The throttle opening is feedback-controlled by taking into consideration the gear position (gear ratio) of the transmission. That is, the vehicle speed is proportional to the drive torque obtained by multiplying the engine output torque by the gear ratio. Therefore, even if the output torque is the same, the vehicle speed varies depending on the gear ratio (gear position). Therefore, if the throttle opening is set only by the deviation between the actual vehicle speed of the vehicle and the target vehicle speed, good constant speed running can be performed, for example, in the 4th speed, but the increase rate of the drive torque becomes too high in the 3rd speed. Vehicle speed overshoot occurs. Therefore, in the constant speed running control device of the above-mentioned publication, by performing feedback control of the throttle opening in consideration of the gear ratio as well, good constant speed running is possible at any gear position.

[0004]

However, in the device disclosed in the above publication, the normal feedback control is performed even during the gear shifting operation, so that the following problems occur. FIG. 3 shows changes in the throttle opening and the vehicle speed when the gear position is changed from the fourth speed to the third speed. Normally, it takes 1 to 2 seconds for the gear shifting operation, but during this time,
As shown in Fig. 3 (a), the drive torque always drops momentarily,
Along with this, the vehicle speed becomes lower than the target speed as shown in FIG. In the feedback control, in response to this decrease in vehicle speed, the throttle opening is increased as indicated by the alternate long and short dash line in FIG. 3 (b) in order to increase the vehicle speed.
As indicated by the alternate long and short dash line in (c), an overshoot of the vehicle speed occurs near the end of the shift.

It is an object of the present invention to provide a vehicle constant speed traveling control device which prevents an overshoot of the vehicle speed due to a decrease in drive torque during a gear shifting operation.

[0006]

According to the invention of claim 1, there is provided feedback control means for feedback-controlling the throttle opening so that the actual vehicle speed matches the target vehicle speed on the basis of the deviation between the actual vehicle speed and the target vehicle speed. It is applied to the vehicle constant speed traveling control device provided. Then, the feedforward control means for controlling the throttle opening to a predetermined value irrespective of the deviation between the actual vehicle speed and the target vehicle speed, and the feedback control means when the automatic transmission is not performing the shifting operation, are operated. The selection means for activating the feedforward control means during the gear shift operation of (1) is used to solve the above problems. The invention according to claim 2 further comprises calculation means for calculating a target throttle opening to be set after the shift using the driving force estimated value before the shift and the gear ratio before and after the shift, and from the start to the end of the shift operation, The feedforward control means is configured to change the throttle opening from a value immediately before the shift start to a value to be set after the shift at a predetermined change rate. According to the third aspect of the present invention, the feedforward control means is configured so as to maintain the throttle opening at the value immediately before the start of the shift. According to a fourth aspect of the present invention, the feedforward control means is provided with the above-mentioned calculation means and holds the throttle opening at a value to be set after shifting.

[0007]

According to the first aspect of the present invention, during the shifting operation of the automatic transmission, the normal feedback control is not performed, and the feedforward control controls the throttle opening to a predetermined value regardless of the vehicle speed deviation. As a result, even if the drive torque decreases during the gear shift operation and the vehicle speed falls below the target speed, the throttle opening does not undesirably increase in response to this decrease in vehicle speed, and vehicle speed overshoot can be prevented. . Particularly, in the invention of claim 2, the target throttle opening to be set after the shift is calculated using the driving force estimated value before the shift and the gear ratio before and after the shift, and the throttle opening is changed from the start to the end of the shift operation. The value immediately before the start of the shift is changed to a value to be set after the shift at a predetermined change rate. In addition,
The throttle opening may be held at a value immediately before the start of the shift or a value to be set after the shift.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing the overall configuration of a constant speed traveling control device according to the present invention. The constant-speed traveling control unit indicated by reference numeral 10 is, for example, a one-chip microcomputer (hereinafter, microcomputer) 11 incorporating a CPU, ROM, RAM, digital port, A / D port, and various timers.
And a Stroller actuator drive circuit 12 for driving and controlling a negative pressure type throttle actuator 34, which will be described later,
It comprises a fail-safe shut-off circuit 13.

All of the switches 21 to 25 are operated by an occupant, and the operating state of each switch is input to the microcomputer 11 of the constant speed traveling control unit 10. Reference numeral 21 is a main switch for constant speed traveling control, 22 is a set switch for starting constant speed traveling control and setting a set vehicle speed, 23 is an accelerator switch for increasing the target vehicle speed, and 24 is a target vehicle speed. Is a coast switch, and 25 is a cancel switch for canceling the constant speed traveling control. When the set switch 22 is turned on after the main switch 21 is turned on, the microcomputer 11 starts constant speed traveling control at the vehicle speed at that time. A brake switch 26 is turned on when the foot brake is operated, and the on / off state thereof is also input to the microcomputer 11.

A vehicle speed sensor 31 using an electromagnetic pickup and a potentiometer type throttle sensor 32 are also connected to the microcomputer 11. The vehicle speed sensor 31 inputs the number of pulse signals corresponding to the actual vehicle speed to the microcomputer 11, and the microcomputer 11 measures the actual vehicle speed by counting the pulses. The throttle sensor 32 inputs an analog signal corresponding to the actual throttle opening to the microcomputer 11, and the microcomputer 11 A / D converts the analog signal to measure the actual throttle opening. The measured throttle opening is used for servo control of the throttle actuator and running resistance estimation as described later.

Reference numeral 33 is a crank angle sensor provided in the engine EG, and the microcomputer 11 measures the engine rotation speed based on the output thereof. Reference numeral 34 denotes a negative pressure type throttle actuator, which adjusts the negative pressure by driving and controlling a vacuum valve driven by a motor and a solenoid valve for opening to the atmosphere as well known, thereby opening the throttle valve (not shown). Adjust. The vehicle speed is determined according to the opening of the throttle valve.

The automatic transmission control unit indicated by the reference numeral 40 controls the automatic transmission AT, and uses the signal line 1 to output a signal indicating the gear position (3rd speed or 4th speed) during constant speed traveling control. Send to the control unit 10. During the constant speed traveling control, the constant speed traveling control unit 10 uses the signal line 2 to send a signal indicating that the constant speed traveling control is being executed, and the signal line 3 to send an overdrive cancel request signal to the automatic transmission. To the control unit 40. The automatic transmission control unit 40 performs shift control based on a command from the constant speed traveling control unit 10 during constant speed traveling control.

Next, the procedure of constant speed running control by the microcomputer 11 of the constant speed running control unit 10 will be described with reference to the flowchart of FIG. This routine is periodically executed every 100 ms when the main switch 21 is turned on. 100m in step S1
During s, the average actual vehicle speed Vsp for 100 ms is calculated from the count value of the number of pulses input from the vehicle speed sensor 31. Further, the average engine rotation speed Ne in 100 ms is calculated from the count value of the number of pulses input from the crank angle sensor 33 in 100 ms. further,
The analog signal from the throttle sensor 32 is A / D converted to calculate the throttle opening Tvo.

In step S2, the cancel switch 2
5 and on / off of the brake switch 26 are determined,
If both are off, the process proceeds to step S3. In step S3, it is determined whether the set switch 22 is on or off,
If it is ON, it is judged that the start of constant speed traveling control has been commanded,
Go to step S4. In step S4, the current actual vehicle speed Vsp is stored as the target vehicle speed Vspr. In step S5, the ASCD operation flag is set to "1", and in step S6, the fail-safe power cutoff circuit 13 is turned on and the process returns.

If it is determined in step S3 that the set switch 22 is off, the process proceeds to step S7. In step S7, it is determined whether the ASCD operation flag is "1", and if "1", it is determined that the constant speed traveling control is being performed, and the process proceeds to step S8. In step S8, it is determined whether or not the shifting operation is in progress. This may be determined, for example, by whether or not the time (1 second to 2 seconds) required for shifting has passed since the shift signal was output to the automatic transmission control unit 40. If the gear shifting operation is not in progress, feedback control calculation is performed in step S9. That is, the target vehicle speed Vsp
The target throttle opening Tvor is calculated by a well-known PI control method or the like based on the deviation between r and the actual vehicle speed Vsp and the gear position (gear ratio) at that time.

On the other hand, when it is determined in step S8 that the gear shifting operation is being performed, the process proceeds to step S10, and feedforward control calculation is performed. That is, irrespective of the deviation between the target vehicle speed Vspr and the actual vehicle speed Vsp, the target throttle opening Tvo
For example, as indicated by the solid line in FIG. 3B, r changes linearly from the actual throttle opening Tvoo immediately before the shift start to the opening Tvon that should be set after the shift from the start T1 to the end T2 of the shift. To

Here, the target throttle opening Tvon to be set after the gear shift is calculated as follows.
First, an engine torque estimated value Teo corresponding to the actual throttle opening Tvoo and the engine speed Ne immediately before the start of gear shifting is obtained from a prestored engine performance map, and the estimated engine torque value Teo and the gear position before gear shifting are determined. Using the corresponding gear ratio (gear ratio) Go and the tire radius R, the driving force estimated value Fo is calculated by the following equation.

[Formula 1] Fo = Teo × Go / R On the other hand, from the vehicle weight M and the vehicle acceleration a,

## EQU2 ## The vehicle acceleration force Fa is calculated by Fa = M × a,

## EQU3 ## The running resistance F is calculated by F = Fo-Fa. This running resistance F corresponds to the running load applied to the vehicle immediately before the shift is started, and the target throttle opening Tvoo to be set after the shift is calculated on the assumption that the running resistance F is the same after the shift. That is,
From the running resistance F, the tire radius R, and the gear ratio (gear ratio) Gn corresponding to the gear position after the gear shift,

## EQU00004 ## The engine torque Ten required after the gear shift is back calculated by Ten = F.times.R / Gn, and the target throttle to be set after the gear shift is completed by using the engine performance map from the engine torque Ten and the engine speed Ne. Find the opening Tvon.

After steps S9 and S10, step S1
1 and using a control technique such as PID control,
Throttle opening deviation Δ (target opening Tvor-actual opening Tvo)
Based on the above, each output pulse width (Tvac, Tvent) to the vacuum pump and the atmosphere opening solenoid valve of the negative pressure type throttle actuator 34 is calculated. In step S12, the vacuum valve output pulse width Tvac (initially Tvaci) is stored in the pulse output register in the microcomputer 11.
And write the solenoid valve output pulse width Tvent for atmospheric release. As a result, the vacuum valve and the atmosphere release solenoid valve of the negative pressure type throttle actuator are drive-controlled via the drive circuit 12, and the throttle opening Tvo
Is adjusted to the target opening Tvor, and the vehicle speed corresponding to the opening is obtained. Then, the process returns.

If it is determined in step S7 that the ASCD operation flag is "0", and if the cancel switch 25 or the brake switch 26 is turned on in step S2, the constant speed traveling control is canceled in step S.
Proceed to 13. In step S13, each flag and variable are initialized, and in step S14, the power cutoff circuit 13 is turned off and the process returns.

According to the above procedure, when the driver turns on the main switch 21 and then the set switch 22 while the vehicle is traveling, the actual vehicle speed Vsp at that time is set to the target vehicle speed Vspr, and constant speed traveling control is performed. Be started. Figure 3
When the gear shift of the automatic transmission AT is not performed, as before the time T1 of, the normal feedback control as described above is performed. That is, from the deviation of the actual vehicle speed Vsp from the target vehicle speed Vspr and the gear ratio according to the gear position at that time, the target throttle opening T
vor is obtained, and the actual throttle opening Tvo is controlled so as to reach this target throttle opening Tvor. As a result, the deviation of the actual vehicle speed Vsp from the target vehicle speed Vspr is suppressed to a minimum, and good constant speed traveling is performed.

On the other hand, when the shifting operation of the automatic transmission AT is started at the time point T1, the feedback control is prohibited and the feedforward control is performed from the time point T1 to the time point T2 at which the shifting operation ends. That is, the target throttle opening Tvor is not calculated from the deviation of the actual vehicle speed Vsp from the target vehicle speed Vspr, but, for example, as shown by the solid line in FIG.
Over 2, the target throttle opening vor should be set after the gear shift from the actual throttle opening Tvoo just before the gear shift starts.
Make it change linearly to on. Then, the actual throttle opening Tvo is adjusted so as to reach the target throttle opening Tvor.
Is controlled. By performing feedforward control of the throttle opening in this manner, for example, when the gear position is changed from the 4th speed to the 3rd speed, the actual vehicle speed Vsp becomes lower than the target speed Vspr even if the drive torque decreases during the gear shift. The throttle opening does not respond to this decrease in vehicle speed, and it is possible to prevent the throttle opening from undesirably increasing. Therefore, unlike the conventional case, the vehicle speed does not overshoot near the end of the gear shift operation, and the deviation of the actual vehicle speed from the target vehicle speed can be minimized.

Particularly in this embodiment, the target throttle opening T
Since vor is made to linearly change from the actual throttle opening Tvoo immediately before the shift start to the opening Tvon that should be set after the shift, a rapid change in the vehicle speed can be suppressed to a minimum.

When the shifting operation is completed at time T2, the feedback control is resumed. In the feedback control of the present embodiment, the throttle opening is controlled by taking into consideration the gear ratio as well as the vehicle speed deviation as described above, so immediately after the end of the gear shifting operation, the throttle opening is set after the gear shifting. The opening degree Tvon is set. Therefore, combined with the effect of the feedforward control described above, it is possible to immediately match the vehicle speed after the shift with the vehicle speed before the shift.

In the configuration of the above embodiment, the constant speed traveling control unit 10 and the throttle actuator 34 constitute feedback control means and feedforward control means, and the microcomputer 11 constitutes selection means and calculation means.

The method of setting the target throttle opening Tvor in the feedforward control is not limited to the method shown in FIG. 3 (b). For example, as shown in FIGS. It can be held at the value just before the start of shifting,
You may make it hold | maintain at the value (calculated by the above-mentioned calculation) which should be set after shifting. Further, the throttle opening actuator is not limited to the negative pressure type actuator, but may be, for example, one using a DC motor or another type of actuator.

[0026]

According to the first aspect of the present invention, during the shifting operation of the automatic transmission, the normal feedback control is not performed, and the feed-forward control is used to maintain the throttle opening at a predetermined value regardless of the vehicle speed deviation. Therefore, even if the drive torque decreases during the gear shifting operation and the vehicle speed falls below the target speed, the throttle opening will not undesirably increase in response to this vehicle speed reduction, and Vehicle speed overshoot can be prevented. Particularly, according to the invention of claim 2, the target throttle opening to be set after the gear shift is calculated using the driving force estimated value before the gear shift and the gear ratio before and after the gear shift, and during the feedforward control, from the start of the gear shift operation. Towards the end, the throttle opening is changed from the value immediately before the shift start to the value that should be set after the shift at a predetermined rate of change, so that the throttle opening does not change rapidly and the vehicle speed changes rapidly. Can be minimized.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of a vehicle constant speed traveling control device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating the operation of the embodiment.

FIG. 3 is a diagram showing changes in drive torque, target throttle opening, and vehicle speed due to gear position change.

FIG. 4 is a diagram showing another embodiment of feedforward control of a target throttle opening.

[Explanation of symbols]

 10 Constant Speed Travel Control Unit 11 Microcomputer 12 Throttle Actuator Drive Circuit 21 Main Switch 22 Set Switch 25 Cancel Switch 26 Brake Switch 31 Vehicle Speed Sensor 32 Throttle Sensor 33 Crank Angle Sensor 34 Negative Pressure Throttle Actuator

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F02D 41/14 320 D 45/00 314 M

Claims (4)

[Claims] 1. A constant speed running control device for a vehicle, comprising feedback control means for feedback-controlling a throttle opening so as to match the actual vehicle speed with the target vehicle speed on the basis of a deviation between the actual vehicle speed and the target vehicle speed. A feedforward control means for controlling the throttle opening to a predetermined value irrespective of the deviation between the actual vehicle speed and the target vehicle speed, and the feedback control means for operating the automatic transmission when a gear shifting operation is not performed, A constant speed traveling control device for a vehicle, comprising: selecting means for activating the feedforward control means during a shift operation of the automatic transmission. 2. A calculation means for calculating a target throttle opening to be set after the shift using a driving force estimated value before the shift and a gear ratio before and after the shift, wherein the feedforward control means comprises the shift operation. 2. The vehicle constant speed traveling control device according to claim 1, wherein the throttle opening degree is changed from a value immediately before the start of gear shift to a value to be set after the gear shift at a predetermined rate of change from the start to the end of. . 3. The vehicle constant speed traveling control device according to claim 1, wherein the feedforward control means holds the throttle opening at a value immediately before the start of gear shifting. 4. A calculation means for calculating a target throttle opening to be set after the shift using a driving force estimated value before the shift and a gear ratio before and after the shift, wherein the feedforward control means is provided for the throttle opening. The vehicle constant speed traveling control device according to claim 1, wherein the degree is maintained at a value to be set after the gear shift.