JPH10119607A - Automobile speed controller for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress any overshoot of a vehicle speed at the time of transmission from deceleration control to constant speed run control. SOLUTION: When decelerating operation for reducing a target vehicle speed is ended (t1), a throttle actuator operational quantity for making acceleration/ deceleration from a vehicle speed detected value to a target vehicle speed is calculated on the basis of a throttle valve opening detection value at the time and according to the calculated operational quantity, the throttle actuator is controlled in drive to open/close the throttle valve. Thereby, when the deceleration operation to the target vehicle speed is ended (t1), even though a control for the purpose of equalizing an actual vehicle speed to the target vehicle speed is started, any overshoot of the vehicle speed can be prevented without over- opening the throttle valve excessively by an already opened amount of the throttle valve.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular constant-speed traveling device for controlling the traveling speed of a vehicle to a target value.

[0002]

2. Description of the Related Art There is known a vehicle speed control device for a vehicle which calculates a target driving force for matching an actual vehicle speed to a target vehicle speed and controls a throttle opening so that the actual driving force matches the target driving force. (See, for example, Japanese Patent Application Laid-Open No. 4-132845).

Also, the target vehicle speed is increased or decreased at a constant rate only while the occupant is operating the acceleration switch or the deceleration switch, and when the occupant has completed the switch operation, the actual vehicle speed at that time is set to the target vehicle speed and is set. 2. Description of the Related Art A vehicle speed control device for a vehicle that performs high-speed running control is known (for example, see Japanese Patent Application Laid-Open
0-56639).

Further, at the start of constant-speed running control, an initial value corresponding to the vehicle speed is set as the throttle opening, and the vehicle speed control for the vehicle is controlled from the initial value based on the deviation between the target vehicle speed and the actual vehicle speed. An apparatus is known (for example, see JP-A-59-160055).

[0005]

However, when the above-described conventional vehicle speed control device is used in a vehicle having a negative pressure type throttle actuator, it is necessary to fully close the throttle by operating a deceleration switch. When the actuator is controlled, the negative pressure of the actuator is released,
It takes a considerable amount of time before the throttle is opened again after negative pressure is stored after the operation of the deceleration switch, so that the vehicle speed largely undershoots.

Therefore, at the start of the constant-speed running control after the end of the deceleration control, an initial value corresponding to the vehicle speed is set in the throttle opening,
A method of controlling the throttle opening from the initial value to prevent the vehicle speed from undershooting can be considered.

However, if the above-described deceleration control is performed in a high speed region or on an uphill, the actual vehicle speed may follow a target vehicle speed that decreases at a constant rate without fully closing the throttle. In such a case, if the throttle opening is controlled from the initial value at the time of constant-speed running control after the end of the deceleration control, the throttle is excessively opened, and an overshoot of the vehicle speed occurs. Further, even when the throttle is fully closed during deceleration, the negative pressure in the actuator is not always completely released, and the negative pressure may remain at the end of the deceleration control. In such a case, when the constant speed traveling control is started and the throttle opening is controlled from the initial value, the throttle is excessively opened, and an overshoot of the vehicle speed occurs.

An object of the present invention is to suppress an overshoot of the vehicle speed when shifting from deceleration control to constant speed traveling control.

[0009]

[Means for Solving the Problems]

(1) The invention according to claim 1 is a negative pressure type throttle actuator for opening and closing a throttle valve, opening degree detecting means for detecting an opening degree of the throttle valve, vehicle speed detecting means for detecting a vehicle speed, and increasing and decreasing a target vehicle speed. An acceleration / deceleration operation member, and target vehicle speed setting means for reducing the target vehicle speed while the deceleration operation is being performed by the acceleration / deceleration operation member, and setting the vehicle speed detection value at the end of the deceleration operation to the target vehicle speed when the deceleration operation ends. A vehicle vehicle comprising: an operation amount calculating means for calculating an operation amount of a throttle actuator for accelerating and decelerating from a vehicle speed detection value to a target vehicle speed; and a drive control means for driving and controlling the throttle actuator according to the calculated operation amount. Applied to speed control devices. When the deceleration operation is completed, the operation amount calculating means calculates the operation amount of the throttle actuator for accelerating or decelerating from the vehicle speed detection value to the target vehicle speed based on the throttle valve opening detection value at that time. When the deceleration operation for reducing the target vehicle speed is completed, the operation amount of the throttle actuator for accelerating and decelerating from the vehicle speed detection value to the target vehicle speed is calculated based on the throttle valve opening detection value at that time, and the calculated operation is performed. The throttle actuator is driven and controlled according to the amount to open and close the throttle valve. (2) A vehicle speed control device for a vehicle according to claim 2, wherein the drive control means includes negative pressure increasing means for increasing the negative pressure of the throttle actuator to drive the throttle valve to the open side, and the operation amount calculating means. Calculates the target throttle valve opening for accelerating and decelerating from the vehicle speed detection value to the target vehicle speed, the target throttle valve opening, the throttle valve opening detection value, and the throttle valve opening when the negative pressure increasing means is continuously operated. An operation amount of the throttle actuator is calculated based on the opening speed. When the deceleration operation for reducing the target vehicle speed is completed, the operation amount of the throttle actuator is calculated based on the detected value of the throttle valve opening at that time, the target throttle valve, and the maximum opening speed of the throttle valve. (3) In the vehicle speed control device for a vehicle according to claim 3, when the throttle valve is closed when the deceleration operation is completed by the drive control means, the negative pressure of the throttle actuator is once released to the atmospheric pressure. (4) The invention according to claim 4 is a negative pressure type throttle actuator for opening and closing the throttle valve, opening degree detecting means for detecting the opening degree of the throttle valve, vehicle speed detecting means for detecting the vehicle speed, and for increasing and decreasing the target vehicle speed. An acceleration / deceleration operation member, while the deceleration operation is being performed by the acceleration / deceleration operation member, target vehicle speed setting means for reducing the target vehicle speed, and setting the detected vehicle speed at the end time to the target vehicle speed when the deceleration operation ends, A vehicle speed comprising: an operation amount calculating means for calculating an operation amount of a throttle actuator for accelerating and decelerating from a vehicle speed detection value to a target vehicle speed; and a drive control means for driving and controlling the throttle actuator in accordance with the calculated operation amount. When the throttle valve is closed at the end of the deceleration operation, the drive control means is applied to the control device. Release the negative pressure of the torque actuator to atmospheric pressure. If the throttle valve is closed when the deceleration operation for reducing the target vehicle speed ends,
Once the negative pressure of the throttle actuator is released to atmospheric pressure.

[0010]

【The invention's effect】

(1) According to the first aspect of the invention, when the deceleration operation for reducing the target vehicle speed is completed, the throttle for accelerating and decelerating from the vehicle speed detection value to the target vehicle speed based on the throttle valve opening detection value at that time. Since the operation amount of the actuator is calculated and the throttle valve is opened and closed by controlling the drive of the throttle actuator according to the calculated operation amount, when the deceleration operation of the target vehicle speed is completed,
Even when the control for matching the actual vehicle speed to the target vehicle speed is started, the throttle valve is not opened excessively by the amount that the throttle valve is already opened, and overshooting of the vehicle speed can be prevented. (2) According to the second aspect of the present invention, when the deceleration operation for reducing the target vehicle speed is completed, based on the throttle valve opening detection value at that time, the target throttle valve, and the maximum opening speed of the throttle valve. Thus, the throttle valve is opened and closed by driving and controlling the throttle actuator according to the calculated operation amount. Therefore, the same effect as the first aspect can be obtained. (3) According to the third aspect of the invention, if the throttle valve is closed when the deceleration operation of the target vehicle speed is completed, the negative pressure of the throttle actuator is once released to the atmospheric pressure. Even if control to match the actual vehicle speed to the target vehicle speed is started when the vehicle speed deceleration operation is completed, the throttle valve will not be opened excessively as much as the negative pressure remains. Can be prevented. (4) According to the fourth aspect of the invention, the same effect as the third aspect of the invention can be obtained.

[0011]

FIG. 1 shows a configuration of an embodiment. The vehicle speed control control unit 1 includes a microcomputer 10, a drive circuit 11, and a fail-safe shutoff circuit 12. The microcomputer 10 includes a memory and an interface, and executes a control program described later to control the traveling speed of the vehicle. Drive circuit 11
Drives the throttle actuator 30 in accordance with a command from the microcomputer 10. Further, the fail-safe shut-off circuit 12 is connected to the battery B when an abnormality occurs.
The power supply from the AT to the actuator drive circuit 11 is cut off, and the constant speed traveling control is stopped.

The control unit 1 includes a main switch 2, a set switch 3, an accelerate switch 4, a coast switch 5, a cancel switch 6, a brake switch 7, a vehicle speed sensor 8, a throttle sensor 9,
The engine speed sensor 13 is connected.

The main switch 2 is a switch for starting or stopping the vehicle speed control device. The set switch 3 is a switch for starting constant speed traveling control and setting the vehicle speed. The accelerate switch 4 is a switch for instructing an increase in the target vehicle speed, and the coast switch 5 is a switch for instructing a decrease in the target vehicle speed. The cancel switch 6 is a switch for releasing the cruise control, and the brake switch 7 is a switch that is activated when the foot brake is operated. When the brake switch 7 is actuated, the cruise control is released in the same manner as when the cancel switch 6 is operated.

The vehicle speed sensor 8 generates a pulse signal at every predetermined traveling distance of the vehicle, and can detect the traveling speed of the vehicle by counting the number of generated pulses in a predetermined time. The throttle sensor 9 detects the actual opening of the throttle. Further, the engine speed sensor 13 generates a pulse signal for each predetermined rotation angle of the engine and counts the number of generated pulses in a predetermined time to detect the engine rotation speed.

The automatic transmission control unit 20 includes:
Drives and controls the automatic transmission (automatic transmission) of the vehicle. The automatic transmission control unit 20 sets the shift position of the third speed (hereinafter, referred to as D3) or the overdrive (hereinafter, referred to as OD) during the constant speed traveling control via the signal line 41 to the control unit 1 for controlling the vehicle speed. Send to In this embodiment, a fourth forward speed transmission including an OD will be described as an example. The control unit 1 for controlling the vehicle speed transmits a constant speed traveling control signal to the automatic transmission control unit 2 via a control line 42.
And sends an OD cancel command during the constant-speed running control to the automatic transmission control unit 20 via the signal line 43.

As shown in FIG. 2, a vacuum pump 31, a vent valve 32, and a safety valve 33 are connected to the negative pressure type throttle actuator 30. In the vacuum pump 31, the diaphragm 31b is driven by the motor 31a, and the negative pressure chamber 30a of the actuator 30 is moved.
To generate negative pressure. The vent valve 32 and the safety valve 33 are used to release the negative pressure of the negative pressure chamber 30a to atmospheric pressure. Control unit 1 for vehicle speed control
Is connected to the vent valve solenoid 32a via the signal line 44.
And the safety valve solenoid 33a and the vacuum pump motor 31a. The negative pressure in the negative pressure chamber 30a is controlled by a vacuum pump 31, a vent valve 32, and a safety valve 33, and the diaphragm 30b moves right and left in the figure according to the negative pressure. Diaphragm 3
The movement of 0b is transmitted to the throttle valve 30d via the accelerator wire 30c, and the throttle valve 30d is opened and closed.

FIG. 3 is a flowchart showing a main routine of vehicle speed control, FIG. 4 is a flowchart showing a coast control routine, and FIG. 5 is a flowchart showing a throttle initialization routine. The operation of this embodiment will be described with reference to these flowcharts. The microcomputer 10 of the control unit 1 executes a main routine shown in FIG. 3 every predetermined time (100 msec in this embodiment). In step 1, based on the measured values of the vehicle speed sensor 8 and the engine speed sensor 13 from the previous execution of the control program to the present, the average actual vehicle speed V
While calculating sp and the average engine speed Ne, the throttle sensor 9 measures the actual throttle opening.
In the following step 2, it is confirmed whether the cancel switch 6 has been operated or whether the brake switch 7 has operated the foot brake.
Alternatively, if the foot brake is operated, the process proceeds to step 21; otherwise, the process proceeds to step 3. When the cancel switch 6 or the foot brake is operated, it is determined that the constant speed traveling control is to be released. In step 21, an ASCD control flag indicating that the constant speed traveling control is being performed and various variables are initialized. Then, in step 22, the supply of power to the actuator drive circuit 11 is cut off by the cutoff circuit 12.

If neither the cancel switch 6 nor the foot brake is operated, it is checked in step 3 whether the set switch 3 is operated. If the set switch 3 has been operated, the process proceeds to step 4 and step 1
The actual vehicle speed Vsp obtained in step is set as the target vehicle speed Vspr and stored. Further, in step 5, the running resistance R when the vehicle travels on a flat road at the target vehicle speed is obtained from the data map stored in the memory in advance, and this is stored as the target driving force initial value Fori.

In step 6, the target driving force initial value F
An output pulse width initial value Tvaci to the vacuum pump 31 necessary for obtaining ori is obtained. First, the target engine torque initial value Teri is calculated using the target driving force initial value Fori.

## EQU1 ## Teri = (Fori.Rt) /Gm.Gf where Gm is the transmission gear ratio, Gf is the final gear ratio, and Rt is the effective radius of the tire.

Next, the target throttle opening initial value Tvo is calculated from the target engine torque initial value Teri and the engine speed Ne using the engine non-linear steady-state characteristic map shown in FIG.
Operate on ri. Then, the target throttle opening initial value Tvo
An output pulse width Tvaci to the vacuum pump 31 required to obtain ri is calculated by the following equation.

Tvaci = Tvori- [eta] + [lambda] where [lambda] is the dead time of the actuator 30, and [eta] is the average rate of change of the actuator 30, which is stored in advance in a memory.

At step 7, an AS indicating that the constant speed traveling control is being performed is performed.
The CD control flag is set, and power is supplied to the actuator drive circuit 11 by the fail-safe shutoff circuit 12 in step 8.

On the other hand, if the set switch 3 has not been operated in step 3, the process proceeds to step 9, where it is determined whether or not the ASCD control flag is set. ASC
If the D control flag is set, the routine proceeds to step 10, where a coast control (deceleration control) routine shown in FIG. 4 is executed.

In step 31 of FIG. 4, it is determined whether the coast switch 5 has been operated. If the coast switch 5 has been operated, the process proceeds to step 36,
Set the coast control flag. And step 3
In step 7, a constant value (in this embodiment, 0.2 km / h) is subtracted from the target vehicle speed Vspr (old) one control cycle before, and the process returns to the main routine.

## EQU3 ## Vspr = Vspr (old) -0.2km / h

On the other hand, if the coast switch 5 has not been operated, the routine proceeds to step 32, where it is confirmed whether or not the coast control flag is set. If the coast switch 5 has not been operated and the coast control in progress flag has been set, it is determined that the coast control (deceleration control) has just ended, and in step 33 the target vehicle speed Vspr is set to the current actual vehicle speed. Set Vsp. At step 34, the coast control flag is cleared, and at step 35, a throttle initialization routine shown in FIG. 5 is executed. If the coasting control flag is not set in step 32, the process returns to the main routine as it is not during the coasting control or immediately after the coasting control ends.

In step 41 of FIG. 5, the throttle sensor 30 is fully closed (= 0) by the throttle sensor 9.
Degree). If not fully closed (> 0 degrees), the routine proceeds to step 42, where the output pulse width Tvaci1 to the vacuum pump 31 is calculated by the following equation.

Tvaci1 = (Tvori−Tvoabs) · η Here, η is the reciprocal of the throttle opening speed when the vacuum pump 31 is continuously operated, Tvoabs is the actual throttle opening at the present time, and Tvori is the initial target throttle opening. It is.

In the conventional vehicle speed control device, even if the throttle valve is open at the end of the coast control, the vacuum pump output pulse width is calculated assuming that the throttle valve is fully closed (0 degree). It became longer, the throttle opening was too wide, and the vehicle speed overshot. In this embodiment, at the end of the coast control, if the throttle valve is open, the output pulse width to the vacuum pump is calculated by subtracting the actual throttle opening from the target throttle opening. The throttle valve is not excessively opened by an amount corresponding to the opening, and the vehicle speed overshoot at the end of the coast control can be prevented.

On the other hand, if the throttle valve 30d is in the fully closed state, the routine proceeds to step 43, where the vent valve 32 and the safety valve 33 are opened in order to release the negative pressure in the actuator 30. In the following step 44, the output width Tvaci2 of the vacuum pump 31 is calculated by the following equation.

Tvaci2 = Tvori · η + λ Here, λ is a dead time from when the negative pressure in the actuator 30 is 0 to when the vacuum pump 31 is continuously operated and the throttle valve 30d starts to open. In step 45, a flag (initialization flag) indicating that the throttle opening is being initialized is set, and the process returns to the main routine.

As described above, even if the throttle valve is fully closed at the end of the coast control, the negative pressure of the throttle actuator does not always reach the atmospheric pressure.
In a conventional vehicle speed control device, when coast control ends,
Since the vacuum pump output is performed even if the negative pressure has not returned to the atmospheric pressure, the actuator negative pressure becomes too large, the throttle valve opens too much, and the vehicle speed overshoot occurs. In this embodiment, at the end of the coast control, if the throttle valve is fully closed, the vent valve and the safety valve are once opened to return the actuator negative pressure to the atmospheric pressure, and then the vacuum pump output is performed. Even if the negative pressure remains at the end, the throttle valve is not opened excessively by that much, the throttle valve can be opened accurately to a desired opening, and overshooting of the vehicle speed can be prevented.

In step 12 after the coast processing,
Check whether the initialization flag is set. As described above, the initialization flag is set in the throttle initialization routine (FIG. 5) executed immediately after the coast control ends, and indicates that the coast control has ended. When the initialization flag is set, the process skips the vehicle speed feedback calculation, the target throttle opening calculation, and the actuator output pulse width calculation, and proceeds to step S13. In step 13, it is confirmed whether or not the safety valve 33 is open. If the safety valve 33 is open in the throttle initialization routine, the process is terminated. If the safety valve 33 is not open, the process proceeds to step 23. move on. Step 2
At 3, the output pulse width Tvac of the vacuum pump 31 is output to the drive circuit 11. Thereby, the vacuum pump 31 of the negative pressure type throttle actuator 30 is driven by the drive circuit 11, and the opening of the throttle valve 30d is adjusted.

On the other hand, if the initialization flag has not been set after the coasting process is completed, a vehicle speed feedback calculation is performed in step S14. First, a final target driving force y1 of the engine for making the actual vehicle speed Vsp coincide with the target vehicle speed Vspr is calculated. This calculation is performed using a vehicle speed feedback compensator based on a model matching method and an approximate zeroing method, which are linear control methods, as shown in FIG.

Here, a vehicle model to be controlled incorporated in the vehicle speed feedback compensator will be described. Since the vehicle is modeled with the target driving force as the manipulated variable and the vehicle speed as the control variable, the transient characteristics of relatively responsive engines and torque converters and the non-linear steady-state characteristics of torque converters can be omitted. The behavior of the power train can be represented by a simple nonlinear model shown in FIG. Then, for example, by using a previously measured engine non-linear compensation map as shown in FIG. 6, a target throttle opening is calculated such that the actual driving force matches the target driving force, and the throttle opening is servo-controlled. In addition, the engine non-linear steady-state characteristics can be linearized. Therefore, a vehicle model having the target driving force as input and the vehicle speed as output has an integral characteristic, and the compensator can set the transmission characteristic of this vehicle model to the pulse transmission characteristic P (z ^-1 ).

In FIG. 7, z is a delay operator, and z
Multiplying by ^-1 gives the value one sample cycle earlier. Also, C1
(Z ^-1 ) and C2 (z ^-1 ) are disturbance estimators based on the approximate zeroing method, and suppress the influence of disturbances and modeling errors. Further, C3 (z ^-1 ) is a compensator based on the model matching method, and as shown in FIG. 9, the target vehicle speed Vsp
The response characteristic of the control object when r is input and the actual vehicle speed Vsp is output is made to match the characteristic of the reference model H (z ^-1 ) having a predetermined first-order delay and a dead time element.

It is necessary to consider the dead time, which is the delay of the power train, as the transfer characteristic of the controlled object. This dead time is about 200 msec, which corresponds to a two-sample period in this embodiment. Therefore, the pulse transfer function P
(Z ^-1 ) can be represented by a product of an integral element P1 (z ^-1 ) and a dead time element P2 (z ^-1 ) (= z ^-2 ) shown in the following equation.

P1 (z ⁻¹ ) = T · z ⁻¹ / {M · (1−z ⁻¹ )} where T is a sample period (100 m in this embodiment).
sec), M is the average vehicle weight.

At this time, the compensator C1 (z ^-1 ) is expressed by the following equation.

C1 (z- ¹ ) = (1-.gamma.) Z- ¹ / (1-.gamma.z- ¹ ), .gamma. = Exp (-T / Tb) That is, compensator C1 (z- ¹ ). Is a low-pass filter with a time constant Tb.

Further, the compensator C2 (z ^-1 ) is C1 / P1
Is represented by the following equation.

C2 = (z ⁻¹ ) = M · (1-γ) · (1-
z ⁻¹ ) / {T · (1−γ · z ⁻¹⁾ } The compensator C2 is obtained by applying a low-pass filter to the inverse system of the vehicle model, and generates a disturbance (running resistance) obtained from the actual vehicle speed Vsp. 8), that is, the driving force obtained by subtracting the running resistance from the driving force as shown in FIG.

If the reference model H (z ^-1 ) is a first-order low-pass filter with a time constant Ta, ignoring the dead time of the controlled object, the compensator C3 has the following constant.

C3 = K = {1-exp (−T / Ta)} · M / T

The model matching compensator C3 shown in FIG.
The operation corresponding to (z ^-1 ) is performed, and the actual vehicle speed Vsp is calculated.
Target driving force y for accelerating the vehicle to target vehicle speed Vspr
Ask for 4. If data y (k-1) represents data y (k) one sample cycle earlier,

Y4 (k) = K · (Vspr (k) −Vsp (k))

Next, a part corresponding to a part of the robust compensator C2 (z ^-1 ) of the disturbance estimator shown in FIG. 7 is calculated, and the influence of disturbance (such as running resistance) is determined based on the actual vehicle speed Vsp. The received driving force y3 is back calculated.

Y3 (k) = γ · y3 (k−1) + (1−
γ) · M · {Vsp (k) −Vsp (k−1)} / T

Further, the target driving force y4 is corrected by the estimated running resistance Fr to obtain the final target driving force y1.

Y1 (k) = y4 (k) − (y3 (k) −y2 (k−2)) = y4 (k) + (y2 (k−2) −y3 (k)), Fr = y2 (K−2) −y3 (k) Here, y2 (k−2) is a value of the driving force y2 (k) described later two sample periods before, and the calculation of the driving force y2 is performed by the integration element P1 ( z ^-1 ), and using the value two sample periods earlier is equivalent to the dead time element P2
This corresponds to the operation of (z ^-1 ). y3 (k) is the actual vehicle speed Vsp
And the driving force y2 (k-2) is a driving force that is not affected by the running resistance obtained in the compensator. Therefore, the difference between the two is the driving resistance estimation. It becomes the value Fr. As described above, the disturbance estimator configured by the approximate zeroing technique can accurately estimate disturbance such as running resistance based on the difference between the output of the controlled object model and the actual output of the controlled object.

Next, the final target driving force y1 is limited within the upper and lower limits. First, the maximum engine torque Temax and the minimum engine torque Temin corresponding to the current engine rotation speed Ne are obtained by using a data table in which the engine torque when the throttle is fully opened and when the throttle is fully closed is measured for each engine rotation speed. Next, the maximum engine torque Te
From the max and the minimum engine torque Temin, a maximum driving force Fmax and a minimum driving force Fmin are obtained by the following equation.

Fmax = Temax · Gm · Gf / Rt, Fmin = Temin · Gm · Gf / Rt where Gm is the transmission gear ratio, Gf is the final gear ratio, and Rt is the effective radius of the tire. Then, the final target driving force y1 is limited within the maximum driving force Fmax and the minimum driving force Fmin.

When y1 (k) ≧ Fmax, y5 (k) = Fmax, when y1 (k) ≦ Fmin, y5 (k) = Fmin, and when Fmin <y1 (k) <Fmax, y5 (k) = y1 (k)

As described above, by limiting the final target driving force within the upper and lower limit values, a steep ascending slope occurs during the constant speed traveling control, and the driving force becomes insufficient even at the maximum driving force of the vehicle, and the actual vehicle speed is reduced. Even if the vehicle speed decreases from the target vehicle speed, the final target driving force input to the disturbance estimator is limited so as not to exceed the actual maximum driving force, and does not become a large target driving force that cannot be actually obtained. No error is accumulated inside the disturbance estimator. Therefore, even after returning to the flat road, the disturbance estimator does not function quickly and the actual vehicle speed does not overshoot. Similarly, even in the case where the vehicle goes down steeply during cruise control and the braking force is insufficient even with the maximum engine braking force, and the actual vehicle speed exceeds the target vehicle speed, the final target input to the disturbance estimator is also used. Since the driving force is limited so as not to be smaller than the actual minimum driving force and does not become a large engine braking force that cannot be actually obtained, no error is accumulated inside the disturbance estimator. Therefore, even after returning to the flat road, the disturbance estimator does not function quickly and the actual vehicle speed does not undershoot.

The operation of a part corresponding to the compensator C1 (z ^-1 ) as a low-pass filter which is a part of the disturbance estimator is performed.

Y2 (k) = γ · y2 (k−1) + (1−
γ) · y5 (k−1) With the above, the calculation of the vehicle speed feedback compensator shown in FIG. 7 is completed, and the process returns to step 15 in FIG.

In step 15, the target throttle opening is calculated based on the final target driving force y1, as shown in FIG. First, a target engine torque Ter per liter of equivalent displacement is calculated from the final target driving force y1.

Where L is the equivalent displacement in liters, and is an index for normalizing the steady-state characteristics of various engines. In this embodiment, for example, the engine displacement is the same as the displacement of a twin cam engine, increased by 20% for a turbocharged engine, and reduced by 30% for a single cam engine. It is sufficient to prepare in advance non-linear steady-state characteristic maps of various types of engines, which are obtained by dividing the engine torque by the equivalent displacement L and normalizing the divided engine torque. It can be seen from these figures that the characteristics are almost the same regardless of the type of engine. Therefore, a target throttle opening corresponding to the engine torque command value Ter and the engine rotation speed Ne is calculated from the engine non-linear steady-state characteristic map normalized by the equivalent displacement.

As described above, the target throttle value corresponding to the engine torque command value and the engine speed is obtained by using the engine non-linear steady-state characteristic map having the engine speed as a parameter, normalized by the equivalent displacement of each engine. Since the opening degree is calculated by a table, the target throttle opening degree can be obtained from the normalized engine non-linear steady-state characteristic map and the equivalent displacement without using the nonlinear steady-state characteristic map of each engine. The complexity of adjusting the non-linear steady-state characteristic map each time according to the type of engine can be eliminated. Further, it is not necessary to store many types of engine non-linear steady-state characteristic maps in the memory in advance. If the torque saturation characteristics of the various engine non-linear steady-state characteristic maps have the same slope in the low-to-medium opening range and vary greatly, a normalized engine non-linear steady-state characteristic map of several engines with different saturation characteristics is prepared. do it.

Next, at step 16, the throttle actuator 30 for setting the throttle opening to the target value is set.
Is calculated. For this calculation, a model matching method, which is a known linear calculation method, is used. Assuming that the transfer characteristic of the controlled object is a pulse transfer function Pa (z ^-1 ), the compensator portion is as shown in FIG.

In the figure, z is a delay operator, and z ^-1
Is multiplied by the value one sample cycle earlier. C4 (z ^-1 )
Is a compensator based on a model matching method, and makes the response characteristic of the control target coincide with the characteristic Ha (z ^-1 ) of the reference model.

Assuming that a portion to be controlled by an actuator drive pulse as an input and a throttle opening as an output is to be controlled, P
a (z ^-1 ) is represented by the following integral element.

Pa (z ⁻¹ ) = Ka · T · z ⁻¹ / (1−z ⁻¹ ) where Ka is the gain in the opening direction of the actuator 30 and T
Is the sample period.

The reference model characteristic Ha (z ^-1 ) is converted to a time constant Tac
If the first-order delay of tr is expressed by the following equation.

Ha (z ⁻¹ ) = (1−λ) · z ⁻¹ / (1−λ · z ⁻¹ ), λ = exp (−T / Tactr)

Therefore, the compensator C4 is expressed by the following equation.

C4 = Ha (z ^-1 ) / Pa (z ^-1 ) = ｛(1
−λ) / Ka · T｝ · (1-z ⁻¹ ) / (1−λ · z ⁻¹ )

In step 23, the output pulse width Tvac of the vacuum pump 31 and the output pulse width Tvent of the vent valve 32 are output to the drive circuit 11. Thereby, the vacuum pump 31 of the negative pressure type throttle actuator 30
And the vent valve 32 are driven by the drive circuit 11, and the opening of the throttle valve 30d is adjusted.

If the set switch 3 has not been operated and both the ASCD control flag and the initialization flag have been set (S3 → S9 → S10), the routine proceeds to step 17, where the safety valve 33 is closed. In the following step 18, it is confirmed whether or not the output pulse width initial value Tvaci to the vacuum pump 31 necessary for obtaining the target driving force initial value Fori is 100 ms or less. If the output pulse width initial value Tvaci is 100 ms or less, the routine proceeds to step 19, where it is determined that the initial setting of the throttle opening has been completed, and the initialization flag is cleared. On the other hand, if the output pulse width initial value Tvaci is greater than 100 ms, the process proceeds to step 20, where the current output pulse width initial value Tvaci is set.
The value obtained by subtracting 100 ms from is set as a new output pulse width initial value Vvaci. Thereafter, the process proceeds to step 23, where the output pulse width Tvac of the vacuum pump 31 and the output pulse width Tvent of the vent valve 32 are output to the drive circuit 11.

FIG. 12 is a diagram showing the control result of the embodiment, and shows changes in the target vehicle speed, the actual vehicle speed, the actual throttle opening, and the pulse width of the vacuum pump. If the throttle valve is open at the end of coast control t1, the actual pulse opening is subtracted from the target throttle opening to calculate the output pulse width Tvaci1 to the vacuum pump. Without opening the throttle valve too much
The vehicle speed overshoot at the end of the coast control can be prevented. For reference, in the conventional vehicle speed control device, even if the throttle valve is open at the end of coast control t1, the vacuum pump output pulse width Tvaci is calculated assuming that the throttle valve is fully closed (0 degree). The width became longer, the throttle opening was too wide, and the vehicle speed was overshot.

FIG. 13 is a diagram showing another control result of the embodiment, in which the target vehicle speed, the actual vehicle speed, the actual throttle opening, the time change of the negative pressure of the throttle actuator, and the pulse widths of the vacuum pump and the safety valve. Is shown. As described above, even if the throttle valve is fully closed at the time t1 when the coast control ends, the negative pressure of the throttle actuator does not always reach the atmospheric pressure. In the conventional vehicle speed control device, at the end of the coast control t1, the vacuum pump output is performed even if the negative pressure has not returned to the atmospheric pressure. Therefore, the actuator negative pressure becomes too large, the throttle valve opens too much, and the vehicle speed exceeds Shoot had occurred. In this embodiment, at the end of coast control t
1. If the throttle valve is fully closed, the vent valve and the safety valve are once opened to return the actuator negative pressure to atmospheric pressure, and then the vacuum pump is output. Therefore, the throttle valve can be opened to a desired degree of opening without excessive opening of the throttle valve, and overshooting of the vehicle speed can be prevented.

In the configuration of the above embodiment, the throttle sensor 9 functions as an opening detecting means, the vehicle speed sensor 8 functions as a vehicle speed detecting means, the accelerator switch 4 and the coast switch 5 operate as acceleration / deceleration operating members, and the microcomputer 1
0 denotes a target vehicle speed setting means and an operation amount calculating means, the microcomputer 10 and the drive circuit 11 constitute a drive control means, and the vacuum pump 31 constitutes a negative pressure increasing means.

In the above-described embodiment, a throttle actuator using a vacuum pump has been described as an example. However, a negative pressure type throttle actuator for introducing a negative pressure of intake air of an engine into a negative pressure chamber through a vacuum valve is used. The present invention can also be applied to vehicles that have been in use. Further, in the above-described embodiment, an example has been described in which both the vent valve and the safety valve are opened at the end of the coast control. However, only one of the safety valve and the vent valve may be opened.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment.

FIG. 2 is a diagram showing a configuration of a negative pressure type throttle actuator of one embodiment.

FIG. 3 is a flowchart showing a main routine of vehicle speed control according to one embodiment.

FIG. 4 is a flowchart showing a coast control routine.

FIG. 5 is a flowchart showing a throttle initialization routine.

FIG. 6 is a diagram showing an engine non-linear steady-state characteristic map.

FIG. 7 is a diagram illustrating a configuration of a vehicle speed feedback compensator.

FIG. 8 is a diagram showing a simplified nonlinear model of a vehicle power train.

FIG. 9 is a diagram showing a configuration of a model matching compensator.

FIG. 10 is a diagram illustrating a method of calculating a target throttle opening.

FIG. 11 is a diagram illustrating a method of calculating a vacuum pump output pulse width.

FIG. 12 is a diagram showing a control result of one embodiment.

FIG. 13 is a diagram showing another control result of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control unit for vehicle speed control 2 Main switch 3 Set switch 4 Accelerate switch 5 Coast switch 6 Cancel switch 7 Brake switch 8 Vehicle speed sensor 9 Throttle sensor 10 Microcomputer 11 Drive circuit 12 Fail safe shutoff circuit 13 Engine speed sensor 20 Automatic Transmission controller 30 Throttle actuator 30a Negative pressure chamber 30b Diaphragm 30c Accel wire 30d Throttle valve 31 Vacuum pump 31a Motor 31b Diaphragm 32 Vent valve 32a Vent valve solenoid 33 Safety valve 33a Safety valve solenoid 41, 43, 44 Signal line 42 Control line B Battery

Claims (4)

[Claims] 1. A negative pressure type throttle actuator for opening and closing a throttle valve, an opening degree detecting means for detecting an opening degree of a throttle valve, a vehicle speed detecting means for detecting a vehicle speed, and an acceleration / deceleration operating member for increasing / decreasing a target vehicle speed. And target vehicle speed setting means for reducing the target vehicle speed while the deceleration operation is being performed by the acceleration / deceleration operation member, and setting the vehicle speed detection value at the end point to the target vehicle speed when the deceleration operation is completed, from the vehicle speed detection value. A vehicle speed control device for a vehicle, comprising: an operation amount calculation unit that calculates an operation amount of the throttle actuator for accelerating and decelerating to a target vehicle speed; and a drive control unit that drives and controls the throttle actuator according to the calculated operation amount. In the above, when the deceleration operation is completed, the operation amount calculation means is configured to perform the operation based on the throttle valve opening detection value at that time. The vehicle automatic vehicle speed control apparatus and calculates the operation amount of the throttle actuator to accelerate or decelerate the vehicle speed detection value to the target vehicle speed. 2. The vehicle speed control device according to claim 1, wherein the drive control unit includes a negative pressure increasing unit that increases a negative pressure of the throttle actuator to drive the throttle valve to an open side. The operation amount calculation means calculates a target throttle valve opening for accelerating and decelerating from a vehicle speed detection value to a target vehicle speed, and calculates a target throttle valve opening, a throttle valve opening detection value, and the negative pressure increasing means. A vehicle speed control device for a vehicle, wherein an operation amount of the throttle actuator is calculated based on an opening speed of the throttle valve when the vehicle is continuously operated. 3. The vehicle speed control device for a vehicle according to claim 1, wherein the drive control means is configured to temporarily control the throttle actuator when the throttle valve is closed when a deceleration operation is completed. A vehicle speed control device for a vehicle, wherein the negative pressure of the vehicle is released to the atmospheric pressure. 4. A negative pressure type throttle actuator for opening and closing a throttle valve, an opening degree detecting means for detecting an opening degree of the throttle valve, a vehicle speed detecting means for detecting a vehicle speed, and an acceleration / deceleration operating member for increasing / decreasing a target vehicle speed. And target vehicle speed setting means for reducing the target vehicle speed while the deceleration operation is being performed by the acceleration / deceleration operation member, and setting the vehicle speed detection value at the end point to the target vehicle speed when the deceleration operation is completed, from the vehicle speed detection value. A vehicle speed control device for a vehicle, comprising: an operation amount calculation unit that calculates an operation amount of the throttle actuator for accelerating and decelerating to a target vehicle speed; and a drive control unit that drives and controls the throttle actuator according to the calculated operation amount. In the above, when the throttle valve is closed when the deceleration operation is completed, the drive control means A negative pressure to open the atmospheric pressure vehicular automatic vehicle speed control apparatus according to claim phlegm the throttle actuator.