JPH1068348A - Positioning control device for throttle valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously control an actual throttle opening in a little step difference by estimating a plurality of disturbances added to an actuator based on a drive command value and a thorttle opening detected value, and selecting the disturbance estimated value according to an engine control condition so as to correct the drive command value. SOLUTION: In a throttle valve positioning controller 4 during operation of an engine, a motor current command value so as to let a throttle valve opening detected value follow to an opening command value is computed, and it is impressed on the motor of a throttle actuator 1 through a current amplifier 5. The controller 4 is provided with a disturbance compensator constituted of filters 11, 12, a limiter 13, and subtracters 14, 15, in order to obtain low sensitivity characteristc against disturbances and variation of parameters for correcting a drive command value by a disturbance estimated value. Further it is provided with a model matching compensators 16-19 for conforming the responsiveness of an actual throttle opening against a throttle opening command value to the prescribed desired responsive characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a throttle valve positioning control device for controlling an intake air amount of an internal combustion engine.

[0002]

2. Description of the Related Art PID control based on a deviation between a throttle valve opening command value and an actual throttle valve opening, PI
A positioning control device based on classical control theory combining control and speed feedback control is known.

[0003]

The throttle valve positioning control device is used for various purposes. For example, normal driving force control to achieve the optimal acceleration feeling based on the accelerator operation of the driver, traction control to suppress the slip of the driving wheels, and constant speed driving control to automatically drive at the vehicle speed set by the driver And engine idle speed control. When a throttle valve positioning control system is used as an actuator for these control purposes, all necessary throttle control performance (response, stability, disturbance suppression, resolution, etc.) is required for each control purpose. Need to be satisfied. In particular, a high throttle control resolution is required when the idle control conventionally performed by controlling a small-diameter auxiliary valve that bypasses the throttle valve is realized by the throttle valve control. In addition, in order to realize the conventional system in which the driver directly operates the accelerator pedal connected to the throttle valve by a wire, the throttle control is controlled by the actuator. Is required.

However, when the butterfly type throttle valve is driven and controlled by an actuator such as an electric motor, various disturbances and non-linear elements (static friction, motor torque ripple, temperature change, suction negative pressure change, throttle opening degree) The influence of measurement noise, throttle opening measurement resolution, etc.) cannot be neglected, and the effect is particularly large in idle control in which the throttle valve is driven and controlled with a small opening. Therefore, in the conventional throttle valve positioning control device,
Since it is greatly affected by disturbances and nonlinear factors, it has been difficult to achieve both throttle control resolution and responsiveness at a high level.

Accordingly, the present applicant has filed Japanese Patent Application No. 7-32047.
No. 6, a throttle valve positioning control device having a disturbance compensator for estimating disturbance applied to an actuator based on an actuator operation amount and a throttle opening and correcting the actuator operation amount to stabilize dynamic characteristics of the actuator. Has been proposed. In this device, when a very high throttle resolution is required as in the idle control, the characteristic is temporarily switched to the characteristic of the disturbance compensator which is more important than that in the normal control. It is generally known that disturbance suppression can be enhanced by increasing the cutoff frequency of a low-pass filter that constitutes a part of the disturbance compensator.

When the cutoff frequency of the low-pass filter is changed, it is general to switch only the constant of the cutoff frequency according to conditions such as the throttle opening. However, when switching the frequency characteristic of the disturbance compensator, the throttle opening, the current command value, and the actuator operation amount become discontinuous. Particularly, when the frequency characteristic is largely changed, a step occurs in the current and the actual throttle opening. There's a problem.

FIG. 11 shows a conventional apparatus in which the throttle opening command value is changed in a ramp shape from 0 to 50 degrees, and the frequency characteristic of the disturbance compensator is switched from 35 Hz to 1 Hz at a throttle opening of 16 degrees. situational,
The simulation results of (a) the throttle opening command value [degree / div], (b) the actual throttle opening value [degree / div], and (c) the current command value [A / div] are shown. As is clear from the figure, the actual throttle opening and the current command value fluctuate greatly when the frequency characteristic of the disturbance compensator is switched,
There is a large step.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a throttle valve positioning control device which suppresses fluctuations in throttle opening when characteristics of a disturbance compensator are changed.

[0009]

[Means for Solving the Problems]

(1) The invention according to claim 1 includes an actuator for opening and closing a throttle valve of an internal combustion engine, and a drive unit for driving the actuator, and a drive command value for causing a throttle opening detection value to follow the opening command value. The present invention is applied to a throttle valve positioning control device that calculates and controls driving means. Then, a plurality of disturbances applied to the actuator are estimated based on the drive command value and the throttle opening detection value with different frequency characteristics, and the plurality of disturbance estimation values are selected according to the engine control state, and the selected disturbance estimation is performed. The drive command value is corrected by the value. (2) The invention according to claim 2 comprises an actuator for opening and closing a throttle valve of an internal combustion engine, and a drive means for driving the actuator, and a drive command value for causing a throttle opening detection value to follow the opening command value. The present invention is applied to a throttle valve positioning control device that calculates and controls driving means. Then, a plurality of disturbances applied to the actuator are estimated based on the drive command value and the throttle opening detection value by different frequency characteristics, and the plurality of disturbance estimation values are interpolated according to the engine control state, and the interpolated disturbance estimation is performed. The drive command value is corrected by the value. (3) The throttle valve positioning control device according to claim 3, wherein the detection accuracy of the throttle valve detection means is switchable, and the disturbance is estimated using the throttle valve detection value at the time of switching to high accuracy. It is. (4) The throttle valve positioning control device according to claim 4, wherein the engine control state includes a throttle valve opening detection value, an engine speed, and an idle control operating state, and a disturbance estimation value is selected according to these engine control states. Or perform interpolation.

[0010]

【The invention's effect】

(1) According to the first aspect of the invention, a plurality of disturbances applied to the actuator are estimated based on the drive command value and the throttle opening detection value based on different frequency characteristics, and the plurality of disturbance estimation values are set in the engine control state. And the drive command value is corrected based on the selected disturbance estimated value, so that the characteristics of the disturbance compensator can be greatly changed in real time, thereby minimizing the step of the actual throttle opening. And it can be continuous. (2) According to the second aspect of the invention, a plurality of disturbances applied to the actuator are estimated based on the drive command value and the throttle opening detection value based on different frequency characteristics, and the plurality of disturbance estimation values are set in the engine control state. , And the drive command value is corrected based on the interpolated disturbance estimated value, so that the same effect as the first aspect can be obtained. (3) According to the third aspect of the present invention, the detection accuracy of the throttle valve detection means can be switched, and a plurality of frequency characteristics having different frequency characteristics based on the throttle valve detection value and the drive command value when switching is performed with high accuracy. A disturbance is estimated, and the plurality of disturbance estimated values are selected or interpolated according to the engine control state, and the drive command value is corrected by the selected or interpolated disturbance estimated value. In addition to the above effects, disturbance due to noise can be reduced, and the step in the actual throttle opening can be further minimized.

[0011]

FIG. 1 is a diagram showing a configuration of an embodiment. The throttle actuator 1 drives a butterfly type throttle valve provided in an intake air flow path of an internal combustion engine. A DC motor is used as a drive source, and the output of the motor is reduced by a speed reducer to open / close a throttle valve biased by a spring. The sensor 2 detects the opening angle of the throttle valve. In this embodiment, an inexpensive potentiometer that outputs an analog signal is used, but a high-precision optical encoder may be used. The sensor signal processing circuit 3 has an amplifier and an A / D converter, and amplifies an analog signal from the angle sensor 2 and converts it into a digital signal. The throttle valve positioning controller 4 is composed of a microcomputer and its peripheral parts, and calculates a motor current command value such that the detected throttle valve opening value follows the opening command value. The current control amplifier 5 controls the switching time of the power transistor so that the actual motor current follows the motor current command value.

In this embodiment, a feedback type current control amplifier using a current detection sensor is used, but the current control amplifier is not limited to this embodiment. For example, based on the throttle opening and the output of a model matching compensator described later, the back electromotive force of the motor is estimated using a dynamic characteristic model of the control object that is stabilized by a disturbance compensator described later. A feed-forward type current control amplifier may be used which corrects the effective voltage obtained from the current command value to calculate and control the switching time of the power transistor for current control.

FIG. 2 is a control block diagram showing the configuration of the throttle valve positioning controller 4. The throttle valve positioning controller 4 is provided with a disturbance compensator 11 to obtain a low sensitivity characteristic with respect to disturbance and parameter fluctuation.
15 and model matching compensators 16 to 19 for matching the responsiveness of the actual throttle opening to the throttle opening command value to a predetermined desired response characteristic.
The current control amplifier 4, the throttle actuator 1, which includes a motor and a valve movable mechanism, the angle sensor 2, and the sensor signal processing circuit 3 are controlled by the controller 4, and the throttle opening command value θr determines whether the throttle valve opening The degree command value (target value) and the current command value Ir are the above-described drive command value (operation amount), and the throttle opening θ is the above-described throttle valve opening detection value (control amount).

First, the disturbance compensators 11 to 15 will be described. The continuous system transfer characteristic Gp (s) of the controlled object from the current command value Ir to the throttle opening θ is represented by (K / (as ² + b)
s + c)) (hereinafter referred to as 0th order / 2nd order), and a transfer characteristic obtained by discretizing this is represented by Gp (z ^-1 ).

(Equation 1)

The zero point (-bp1 / bp) of Gp (z ^-1 )
0) converges to −1 as the sampling time is shorter, and therefore, if the inverse system of Gp (z ⁻¹ ) is used for the compensator, it becomes unstable. To avoid this, a disturbance compensator is designed as follows. The control block 11 adds Gp to the low-pass filter H0 (z ⁻¹ ) having a steady-state gain of 1.
(Z ^-1) is the filter H obtained by adding the Q (z ^-1) having a zero point (z ^-1). The control block 11 performs a low-pass filter process on the current command value Ir to perform the current command value Ir ′
Is output.

H (z ^-1 ) = H0 (z ^-1 ) · Q (z ^-1 )

The control block 12 includes a filter H (z ^-1 ) /
Gp (z ^-1 ). Therefore, the zero points converging to -1 are canceled, and the control block 12 becomes a stable digital filter. The control block 12 controls the current command value I
The current command value is inversely calculated based on the discrete system transfer characteristic Gp (z ^-1 ) of the controlled object from r to the throttle opening θ and the throttle opening θ. The subtractor 14 outputs the current command value I.
The current command value Ir ′ is subtracted from r ″, and a deviation u2 of the current command value Ir due to a disturbance of a control target from the current amplifier 5 to the sensor signal processing circuit 3 or a parameter variation (hereinafter referred to as a disturbance estimation value). Further, the subtractor 15 subtracts and corrects the disturbance estimation value u2 from the current command value u1 to correct the current command value Ir, and eliminates the influence of disturbance and parameter fluctuation.
Is output.

The disturbance estimation value u2 becomes zero when there is no disturbance or parameter fluctuation in the control target. Disturbance d
Or parameter variation Δ,

(Equation 3) In the frequency band where the gain characteristic of H (z ^-1 ) is 1,

４ = Gp (z ⁻¹ ) · u1 That is, the influence of the disturbance and the parameter fluctuation is completely canceled, and the dynamic characteristics of the control target are fixed to the nominal model Gp (z ^-1 ). When the cutoff frequency of H (z ^-1 ) is increased, the same effect can be obtained up to a high frequency range. However, a high gain feedback is obtained, and the stability margin is reduced. The control block 13 is a limiter corresponding to the upper and lower limits of the motor current. By limiting the input of the disturbance compensator when the motor current, which is the input of the actual control target, is saturated, an error is accumulated in the estimated disturbance value u2. To prevent the response performance from deteriorating.

Next, the model matching compensators 16 to 19
Will be described. First, a desired response characteristic is given as a continuous system reference model transfer characteristic Gm0 (s) (0th order / 2nd order).
If this is the discretized reference model transfer characteristic Gm0 (z ^-1), in the same manner as the control target of the transfer characteristic Gp (z ^-1), with a zero point to converge to -1 The smaller the sampling time. Therefore, the reference model transfer characteristic G is used for the purpose of canceling both when designing the model matching compensator.
The zero point of m0 (z ^-1 ) is set to the control target transfer characteristic Gp (z ^-1 ).
Gm (z ^-1 ) replaced with the zero point of is used as the reference model transfer characteristic. If the sampling time is sufficiently short, there is almost no difference between Gm (z ^-1 ) and Gm0 (z ^-1 ), and there is no practical problem.

(Equation 5)

Using the coefficients of Equations 1 and 5, the control block 16 of the model matching compensator uses 1 / R
(Z ^-1 ), the control block 17 is composed of L (z ^-1 ), and the control block 18 is composed of Bmf.

(Equation 6)

FIG. 3 is a flowchart showing a control program of the throttle valve positioning controller 4. With reference to this flowchart, the positioning operation of the throttle valve of the embodiment will be described. The microcomputer of the controller 4 executes this control program from step 1 every 2 mS. In step 2, sensor 2
The voltage signal corresponding to the opening angle θ of the throttle valve is amplified and A / D converted. In the following step 3, the voltage signal converted into the digital signal is converted into the throttle opening θ. In step 4, the opening command value θr of the actuator is determined by the accelerator operation of the occupant or the like.

In step 5, switching of the throttle opening with different accuracy is performed. When the analog output signal of the throttle angle sensor 2 is amplified and A / D-converted and used as a throttle opening measurement value in the calculation of the disturbance compensators 11 to 15 and the model matching compensators 16 to 19, the analog output signal of the sensor 2 is obtained. In some cases, the disturbance compensators 11 to 15 may not function sufficiently, and the target throttle control resolution may not be achieved.

Therefore, as shown in FIG. 4, the analog output signal of the throttle angle sensor 2 is greatly amplified (four times in this example) to relatively reduce high-frequency noise exceeding the effective frequency range of the amplifier. Also, since the input voltage of the A / D converter naturally has an upper limit, this is performed only in the low throttle opening range during idle control where a very high throttle control resolution is required. As shown in FIG. 5, a normal A / D conversion value that is not amplified is interpolated and used as a throttle valve opening detection value. In order to smoothly connect both A / D conversion values, an interpolation operation is performed between the two based on a normal A / D conversion value that is not amplified or a value obtained by performing an interpolation operation one sample cycle earlier.

[Mathematical formula-see original document] Interpolation value = k * (A / D conversion value 2) + (1-k)
(A / D conversion value 1), where (A / D conversion value 1) ≦ θ, k = 1, θ2
<(A / D conversion value 1 <θ1 when 0 <k <1, θ2 ≦
In the case of (A / D conversion value 1), k = 0.

In step 6, the frequency characteristics of the robust compensators of the control blocks 11 and 12 shown in FIG. 2 are switched according to the engine control state. Details of this processing will be described later. In step 7, the model matching compensators 16 to 19 shown in FIG. 2 match the response of the actual throttle opening with respect to the throttle opening command value to a predetermined desired response characteristic. Then, in Step 8, the disturbance estimation value u2 calculated by the disturbance compensators 11 to 14 is subtracted from the current command value u1 calculated by the model matching compensators 16 to 19 shown in FIG. A current command value Ir excluding the influence is obtained and output to the current control amplifier 5.

FIG. 6 is a flowchart showing details of the robust compensator in step 6 of FIG. In steps 9 and 10, the disturbance estimation value 1 and the disturbance estimation value 2 are calculated by the robust compensator 1 (cutoff frequency f1 [Hz]) and the robust compensator 2 (cutoff frequency f2 [Hz]) having different frequency characteristics. I do. Next step 11
Then, the disturbance estimation value 1 or the disturbance estimation value 2 is selected according to the actual throttle opening θ which is the control state quantity of the engine.

When θ> θo, the disturbance estimation value 1 is selected, and θ <
In case of θo, select disturbance estimation value 2

As described above, by selecting a plurality of disturbance estimated values calculated by the plurality of disturbance compensators according to the engine control state such as the throttle opening, the characteristics of the disturbance compensator are largely changed in real time. As a result, the step of the actual throttle opening can be minimized and made continuous.

Modification of Embodiment of the Invention FIG. 7 is a flowchart showing a modification of the robust compensator in step 6 of FIG. In the above embodiment, 2
The example in which the disturbance estimation value obtained by the robust compensators is selected based on the throttle opening has been described. In this modification, the disturbance estimation value is interpolated by the following equation according to the throttle opening.

[Equation 9] Interpolated value = k · (disturbance estimated value 2) + (1−k) ·
(Estimated disturbance value 1) Here, k = 1 when θ ≦ θ1, 0 <k <1 when θ2 <θ <θ1, and k = 0 when θ2 ≦ θ.

FIG. 10 shows that the controller of this modification changes the throttle opening command value in a ramp shape from 0 to 50 degrees, and changes the frequency characteristic of the disturbance compensator from 35 Hz to 1 Hz at a throttle opening of 16 degrees. (A) Throttle opening command value [degree / di
v], (b) simulation results of actual throttle opening [degree / div] and (c) current command value [A / div]. As is apparent from this figure, the frequency characteristic of the disturbance compensator can be largely switched without affecting the behavior of the actual throttle opening degree by a step or the like.

-Other Modifications of Embodiment of the Invention-In the above-described embodiment and its modifications, the output of the throttle opening sensor 2 is greatly amplified and A / D converted, and the normal A that is not amplified is output. / D conversion value and interpolation calculation. However, in this modified example, the output of the throttle opening sensor 2 is greatly amplified to reduce the influence of noise and the like, and only when a high-precision throttle opening is used, FIG.
The processing shown in is performed.

FIG. 8 is a flowchart showing another modification of the robust compensator in step 6 of FIG. In step 13, a high-precision throttle opening in which the output of the throttle opening sensor 2 is greatly amplified to reduce the influence of noise and the like, and a normal throttle opening which is not amplified under predetermined conditions (in this modified example, the throttle opening). Degree). And steps 9 and 10 as described above.
In the above, the robust compensator 1 (the cutoff frequency f1
[Hz]) and the robust compensator 2 (cutoff frequency f2
[Hz]), the disturbance estimation value 1 and the disturbance estimation value 2 are calculated. In the following step 14, as shown in FIG. 9, the disturbance estimation value 1 and the disturbance estimation value 2 are selected or interpolated based on the throttle opening θ as described above.

As described above, in this modified example, only when a high-precision throttle opening is used, a plurality of disturbance estimated values calculated by a plurality of disturbance compensators are determined in accordance with an engine control state such as a throttle opening. By selecting or interpolating, the characteristics of the disturbance compensator can be largely changed in real time, whereby the step of the throttle opening can be minimized and made continuous.

In the above-described embodiment and its modification, 2
Although an example using three robust compensators has been described, a disturbance estimation value is calculated using three or more robust compensators, and either of them is selected from the throttle opening or each other is determined based on the throttle opening. The final disturbance estimation value may be obtained by interpolation. In the above-described embodiment and its modification,
Although the example in which the throttle valve opening is used as the engine control state has been described, the engine control state may be an engine speed, an idle control operation state, or the like.

In the configuration of the above embodiment, the motor and the valve movable mechanism serve as the actuator, the current control amplifier 5 serves as the driving means, the throttle angle sensor 2 and the sensor signal processing circuit 3 serve as the detecting means, and the throttle valve positioning controller 4 Constitute the control means, the disturbance estimation means, the selection means, the interpolation means, and the correction means, respectively.

[Brief description of the drawings]

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

FIG. 2 is a control block diagram illustrating a configuration of a throttle valve positioning controller.

FIG. 3 is a flowchart showing a control program of a throttle valve positioning controller.

FIG. 4 Amplifies the output of the throttle opening sensor to obtain A /
FIG. 9 is a diagram illustrating a method of obtaining a throttle opening by interpolating a value obtained by D-conversion and a value obtained by A / D conversion without amplification.

FIG. 5 is a diagram illustrating an interpolation calculation of a throttle opening.

FIG. 6 is a flowchart showing details of a robust compensator in step 6 of FIG. 3;

FIG. 7 is a flowchart showing a modification of the robust compensator in step 6 of FIG.

FIG. 8 is a flowchart showing another modified example of the robust compensator in Step 6 of FIG. 3;

9 is a diagram illustrating the operation of the robust compensator shown in FIG.

10 changes the throttle opening command value in a ramp shape from 0 to 50 degrees by the control device of the modification shown in FIG. 7, and changes the frequency characteristic of the disturbance compensator from 35 Hz to 1 Hz at a throttle opening of 16 degrees. (A) throttle opening command value [degree / div],
It is a figure which shows the simulation result of (b) actual throttle opening [degree / div] and (c) current command value [A / div].

FIG. 11 shows a conventional device that changes a throttle opening command value from 0 degree to 50 degrees in a ramp shape,
When the frequency characteristic of the disturbance compensator is switched from 35 Hz to 1 Hz at a throttle opening of 16 degrees, (a) a throttle opening command value [degrees / div], (b) an actual throttle opening [degrees / div] and ( c) Current command value [A / di
v] is a diagram showing a simulation result of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Throttle actuator 2 Throttle angle sensor 3 Sensor signal processing circuit 4 Throttle valve positioning controller 5 Current control amplifier 11-15 Disturbance compensator 16-19 Feedback type model matching compensator

Claims (4)

[Claims] 1. An actuator for opening and closing a throttle valve of an internal combustion engine, a driving unit for driving the actuator, a detecting unit for detecting an opening of the throttle valve, and a throttle opening detection value as an opening command value. A throttle valve positioning control device comprising: a drive command value for following and controlling the drive means by controlling the drive command value, wherein a plurality of disturbance estimating means having different frequency characteristics from each other; A plurality of disturbance estimating means for estimating a disturbance applied to the actuator based on the throttle opening detection value and a plurality of disturbance estimation values estimated by the plurality of disturbance estimating means in accordance with an engine control state Selecting means, and correcting means for correcting the drive command value based on the disturbance estimated value selected by the selecting means; A positioning control device for a throttle valve, comprising: 2. An actuator for opening and closing a throttle valve of an internal combustion engine, a driving unit for driving the actuator, a detecting unit for detecting an opening of the throttle valve, and a throttle opening detection value as an opening command value. A throttle valve positioning control device comprising: a drive command value for following and controlling the drive means by controlling the drive command value, wherein a plurality of disturbance estimating means having different frequency characteristics from each other; A plurality of disturbance estimating means for estimating a disturbance applied to the actuator based on the throttle opening detection value and a plurality of disturbance estimating values estimated by the plurality of disturbance estimating means in accordance with an engine control state Interpolating means, and correcting means for correcting the drive command value with a disturbance estimated value interpolated by the interpolating means, A positioning control device for a throttle valve, comprising: 3. The throttle valve positioning control device according to claim 1, wherein said detection means is configured to switch detection accuracy, and said disturbance estimating means is switched with high accuracy. A throttle valve positioning control device using a detected value of the throttle valve. 4. The throttle valve positioning control device according to claim 1, wherein the engine control state includes the throttle valve opening detection value, an engine speed, and an idle control operation state. A throttle valve positioning control device, characterized in that: