JP3248358B2 - Engine control method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control method and apparatus in which a throttle actuator is included in a control target in an engine test or the like and sliding mode control (SM control) is introduced.

[0002]

[Prior art]

<Symbols> Among symbols appearing in the description and drawings, lowercase s is a Laplace operator and uppercase S is a sliding line constant. When the variable is generalized to A, the derivative of A with respect to time t (dA / d
The t) represents the A ^(1), 2-order derivative with respect to time t A a (d ² A / dt ²⁾ indicates the A ^(2), expressed as ∫A and differential (∫Adt) with respect to time t of the A. Further, when the control command and the controlled variable of the deviation and the ^{_{x 1, x 1 (1)}} [= dx 1 / d
t] is expressed as x _2, and x ₁ ⁽²⁾ [= d ² x ₁ / dt ² ] is expressed as x ₂
^It may be expressed as ⁽¹⁾ .

<Outline of Engine Test> In an engine test, the opening and closing of a throttle valve of an engine is controlled and operated by an engine control device by an engine control device, and the intake pressure, torque and rotation speed (rotation speed) at that time are operated.
And so on. Recently, NOx and S
Ox regulations are becoming stricter, and gas emitted from engines has become a problem. For this reason, it is important to improve the engine performance, and accordingly, it is necessary to improve the performance of a device for testing the engine.

[0004] Among the engine tests, a test for measuring exhaust gas is performed by operating the engine while changing the torque and the number of revolutions of the target engine according to a predetermined pattern. As described above, the operation of the engine is performed by controlling the throttle actuator by the engine control device to open and close the throttle valve.

[0005] For example, when torque is controlled by an engine control device, a dynamometer (dynamo) connected to the engine is used.
While controlling the number of revolutions to the target value, the engine actuator controls the throttle actuator to open and close the throttle valve, thereby controlling the torque to the target value. Conversely, when controlling the rotation speed with the engine control device, control the torque to the target value with the dynamometer, control the throttle actuator with the engine control device to open and close the throttle valve, and set the rotation speed to the target value. Control.

<Conventional Engine Control Device> Conventionally, an engine control device mainly applying PI (proportional-integral) control has been used. FIG. 11 is a diagram showing a configuration example of this type of engine control device, and FIG. 12 is a block diagram of a control system.

The control target 60 of the engine control device 50 includes a throttle actuator 70, and a throttle valve 81 of an engine 80 is connected to the throttle actuator 70 via a wire 82 as described later.
A dynamometer (dynamo) 90 is connected to the engine 80. The throttle actuator 70 includes a motor 71 such as an AC servomotor, a gear 72 for reducing the rotation of the motor 71, a clutch 73 provided between the reduction gear 72 and the motor 71, and a pulley 74 connected to the reduction gear 72. . One end of a wire 82 is connected to a throttle valve 81 of the engine 80, and the other end of the wire 82 is wound around a pulley 74 of a throttle actuator 70. The wire 82 is passed through the outer 83 and supported. In the figure,
Reference numeral 84 denotes a spring for returning the throttle valve 81 to the initial state (throttle opening 0%). Therefore, the motor 71
The pulley 74 rotates by the rotation of, and the wire 82 is wound or unwound, whereby the throttle valve 81 opens and closes.

The engine 80 and the dynamo 90 are used to detect the engine torque _Tor for feedback.
And a torque detector 54 is provided therebetween. Also, since it is necessary to know the throttle opening θ of the throttle valve 81 for feedback, the throttle actuator 7
The gear 55 is provided on the zero pulley 74 to detect the position of the actuator, which is artificially used as the throttle opening θ.

The engine controller 50 comprises a throttle actuator position command calculator 51, a throttle actuator position controller 52, and a driver 53 for a motor 71. As shown in FIG.
The deviation x ₁ between the torque command T _or ^* and the current torque T _or (= T
_or ^* −T _or ), a throttle actuator position command θ ^* is created by PI control and given to the control unit 52. The controller 52 creates an actuator speed command ω ^* by P (proportional) control from a deviation (θ ^* −θ) between the throttle actuator position command θ ^* and the current throttle actuator position θ, as shown in FIG. From the deviation (ω ^* −ω) between the actuator speed command ω ^* and the actuator speed ω detected by the sensor, a motor control signal 56 is created by PI control and given to the driver 53. The driver 53 supplies a current to the motor 71 according to the motor control signal 56 to rotate the motor 71.

Accordingly, in the conventional engine control device 50 shown in FIG. 11, when the amount of control the torque of the engine 80, the torque command T _or ^* and the current torque T _or the deviation (x ₁ = T _or ^* -T _or) is prepared by a throttle actuator position command theta ^* PI control such that the zero, further, deviation between the throttle actuator position command theta ^* and the current throttle actuator position θ (θ ^* -θ) is zero Such a motor control signal 56 is generated by P control and PI control, and the throttle actuator 70 is controlled via the driver 53.

In FIG. 12, AΘR is an actuator position control system, ASR is an actuator speed control system,
ATR is an engine torque control system. Further, K _T is a motor torque constant, 1 / J _s is a constant based on the total inertia of the rotating portion of the throttle actuator 70, and 1 / s is an integral element representing conversion from the actuator speed ω to the throttle opening θ.

[0012]

However, the throttle actuator 70, the throttle valve 81, and the wire 82 directly connecting them have mechanically non-linear elements such as a hysteresis element and a play element, and have mechanical friction. These are disturbances to the control system. In addition, engine characteristics change and there is diversity.

Therefore, in the conventional engine control device 50 mainly using PI control, the control may be in an unstable state or a limit cycle state. That is, the control target 6
Since the characteristic of 0 can be represented as shown in FIG. 13, when the hysteresis element of the wire 82 is large, an example of a control response as shown in FIG. 14 is obtained, and a hunting phenomenon occurs to be unstable. FIG. 15 shows an example of a control response when the hysteresis element of the wire 82 is small.

The present invention has been made in view of the above-described problems of the prior art, mainly PI control, and introduces a sliding mode control to provide a stable control response to a hysteresis element, a play element, and a variety of engine characteristics. It is an object of the present invention to provide an engine control method and apparatus capable of obtaining the above.

[0015]

The engine control method according to the first invention for achieving the Means for Solving the Problems] The foregoing objects, in the engine control method comprising the slot Le actuator to the controlled object: a gain for the control of the control target, the control Variably controlling the target sliding line constant toward zero; adding a dither signal to the manipulated variable for the control target so as to suppress a steady-state deviation due to disturbance;
Stopping the addition of the dither signal when the control deviation is within an allowable error range. Furthermore,
An engine control method according to a second invention is an engine control method including a throttle actuator as a control target: variably controlling a gain for the control of the control target so that a sliding line constant of the control target is zero; The sliding line constant is composed of a component proportional to a control deviation, a component proportional to a time derivative of the control deviation, and a component proportional to a time integral of the control deviation ;
The manipulated variable for the control object, it adds a dither signal to suppress the steady-state error due to the disturbance; operation with respect to the controlled object; to cancel the addition of the dither signal, when the control deviation is within the tolerance range Filtering the quantity with a first order lag.

An engine control apparatus according to a third aspect of the present invention for achieving the above-mentioned object is an engine control apparatus including a throttle actuator as a control object, wherein the transfer function of the throttle actuator is 1 / (1 + sT ₁ ) and the transfer function of the engine is 1 / (1 + sT ₂ ), where c is 0 <c <(T ₁ + T
_{2) / (T 1 T 2} ), the deviation between the control commands the x ₁ L ^* and the controlled variable L, x ^{_{1 (1)}} the time differential of the deviation x _1, gain Φ for deviations x _1, the alpha alpha> c (T ₁ + T ₂ ) −T ₁ T ₂ c ² −
1. When β is β <c (T ₁ + T ₂ ) −T ₁ T ₂ c ² −1 and K _f is a dither signal value: A deviation x ₁ between the control command L ^* and the current control amount L is obtained. From the deviation x ₁ and a predetermined coefficient c, S = c · x ₁ + x ₁
⁽¹⁾ means for obtaining a sliding line constant S by the following operation: a product x ₁ · S of the deviation x ₁ and the sliding line constant S
Means for determining the sign of the product x ₁ · S, and setting the gain Φ to a predetermined value α when x ₁ · S> 0, and to a predetermined value β when x ₁ · S <0. Means for switching; gain Φ is multiplied by torque deviation x ₁ , and Φ · x ₁ is _one of the manipulated variables: Judgment of the positive or negative of the sliding line constant S, and K _f when the dither signal value is S> 0 a, S <switched -K _f when the _{0, K f · sign (S} ) means for one of the operation amount; control instruction L ^* and the manipulated variable [Phi · x ₁ and K _f · sign
Means the final control u for the basic manipulated variable u controlled object by performing filtering processing of the primary delay to _B;; (S) and adding to the means for obtaining the basic manipulated variable u _B in advance with the deviation x ₁ Compare with the set tolerance e _min ,
Means for setting the dither signal value _Kf to zero when -e _min <x ₁ <e _min .

An engine control device according to a fourth aspect of the present invention is an engine control device including a throttle actuator as a control object, wherein the transfer function of the throttle actuator is 1
/ (1 + sT ₁ ) and the transfer function of the engine is 1 / (1 + s
T ₂ ), 2ξω _n is calculated as 2ξω _n <(T ₁ + T ₂ ) / (T
₁ T ₂ ), x ₁ is the deviation between control command L ^* and control amount L, x ₁
⁽¹⁾ the time differential of the deviation x _1, the time integral of the deviation x ₁ to ∫X _1, gain [Phi ₁ for deviation x _1, integrating the Φ ₂ ∫x ₁
, And α ₁ is α ₁ > [(T ₁ + T ₂ ) −2ξω _n
T ₁ T ₂ ] 2ξω _n -1 + T ₁ T ₂ ω _n ² , β ₁ is β ₁ <
[(T ₁ + T ₂ ) -2ξω _n T ₁ T ₂ ] 2ξω _n -1 + T ₁ T _2
Let ω _n ² and α ₂ be α ₂ > (T ₁ + T ₂ ) ω _n ² -2 ξω _n ³ T
_{Let 1} T ₂ and β ₂ be β ₂ <(T ₁ + T ₂ ) ω _n ² −2 ξω _n ³ T ₁ T
From the deviation x ₁ with a predetermined coefficient 2Kushiomega _n and omega _n ² Prefecture; control instruction L ^* a control amount L and means for determining the deviation x ₁ in _2, when the K _f a dither signal value
^{_{S = x 1 (1) +}} 2ξω n x 1 + ω n 2 ∫x 1 becomes operational by obtaining the sliding line constants S means and; deviation x ₁ and the product S · x ₁ with sliding line constant S
Means for determining the sign of the product S · x ₁ and setting the gain Φ ₁ to S · x ₁ > 0
Means for switching to a predetermined value α ₁ when S · x ₁ <0, and a means for switching to a predetermined value β ₁ when S · x ₁ <0; Gain Φ ₁ is multiplied by deviation x ₁ , and Φ ₁ · x ₁ is 1
Means for bracts: means for determining the product S · ∫x ₁ with integral ∫X ₁ and sliding line constant S of the deviation; determining the sign of the product S · ∫x _1, the gain [Phi ₂ S · ∫
means for switching to a predetermined value α ₂ when x ₁ > 0, and to a predetermined value β ₂ when S · ∫x ₁ <0; multiplying the gain Φ ₂ by the deviation deviation ∫x ₁ , Φ ₂・ ∫x ₁
Means for one of the manipulated variable: determining the sign of sliding line constant S, a dither signal value to a K _f when the S> 0, when the S <0 switched -K _f, K _f · sign Means for setting (S) as one of the manipulated variables; and adding a control command L ^* to the manipulated variables Φ ₁ · x ₁ , Φ ₂ · ∫x ₁ and K _f · sign (S) to perform an operation on the control target. And means for measuring the amount.

According to a fifth aspect, in addition to the fourth aspect , the control command L ^* , the manipulated variables Φ ₁ · x ₁ , Φ ₂ · ∫x _1, and K _f · sig
means the amount of operation n (S) is formed by adding performs a filtering process of first order lag and final control; comparing the tolerance e _min a predetermined said deviation x _1,
Means for setting the dither signal value _Kf to zero when -e _min <x ₁ <e _min .

[0019]

Since the present invention is based on the sliding mode control, it is possible to stably control the control object including the play element and the hysteresis element with a small amount of overshoot. In particular, chattering can be suppressed by performing a first-order lag filter process on the operation amount for the control target. Also, chattering can be suppressed by setting the dither signal added to the operation amount to zero according to the control deviation. Along with the suppression of chattering, it is possible to mitigate adverse effects on control due to aging or failure of a mechanical system included in the control target. Further, by including a component proportional to the control deviation, a component proportional to the time derivative thereof, and a component proportional to the time integral to the sliding line constant, a steady deviation does not occur even if the dither signal is reduced.

<Principle of Sliding Mode Control with S = c · x ₁ + x ₁ ⁽¹⁾ > Referring to FIG. 2, sliding mode using S = c · x ₁ + x ₁ ⁽¹⁾ as sliding line constant S The principle of the control will be briefly described. In general, there are deviations x ₁ between the control instruction L ^* and the controlled variable L, x ₁ = L ^* -L becomes relevant. At this time, the differential deviation x ₁ the deviation x ₁ obtained by differentiating with respect to time _{^{t (1) [= dx 1}} / d
and t], the relationship between the original deviation x ₁ can be expressed by the phase plane as shown in FIG.

In the phase plane shown in FIG. 2, (x ₁ ,
x ₁ ⁽¹⁾ ) = (0,0) is a stable state without a steady-state deviation. Therefore, the point (x ₁ , x ₁ ⁽¹⁾ ) is converted to c · x
^{_{1 + x 1 (1) =}} 0 becomes the control to direct the asymptotically stable state (0,0) along a line is considered, as compared with the conventional PI control, if included backlash and hysteresis in the control subjects , Control is stabilized. However, c> 0. That is, the sliding line constant S is expressed as S = c × x ₁ + x ₁
^It may be detected as ⁽¹⁾ and controlled so that S = c · x ₁ + x ₁ ⁽¹⁾ = 0. This is the sliding mode control, switch the gain Φ for the deviation x ₁ in accordance with the sliding line constants S. In addition, a dither signal is added to the manipulated variable to suppress the steady-state error due to disturbance,
It switched to positive or negative in accordance with the value K _f to sliding line constants S.

For example, when the sliding line constant S is in a region larger than zero in the phase plane shown in FIG.
A control such that the sliding line constant S is directed to a region smaller than zero, that is, a differential sliding line constant S obtained by differentiating the sliding line constant S with respect to time t.
⁽¹⁾ Gain Φ such that [= dS / dt] becomes S ⁽¹⁾ <0
And by performing the switching control of the dither signal value K _f, sliding line constant S is a stable state.

On the other hand, when the sliding line constant S is in a region smaller than zero in the phase plane shown in FIG. 2, control is performed so that the sliding line constant S is larger than zero, that is, the differential sliding line constant S
⁽¹⁾ Gain Φ such that [= dS / dt] becomes S ⁽¹⁾ > 0
And by performing the switching control of the dither signal value K _f, sliding line constant S is a stable state.

Therefore, in the sliding mode control,
The control represented by the following equation (1) is performed so as to satisfy the above two conditions.

[0025]

(Equation 1)

<Error System of Controlled Object> As shown in FIG. 3, the characteristics of the throttle actuator 70 and the engine 80, which are the controlled object 60 of the engine control device 1, are first-order lag systems 1 / (1 + sT ₁ ) and 1 / ( 1 + sT ₂ ), the error system of the control target 60 is expressed by the following equation (2). The reason is as follows. Incidentally, the time constant is lowercase s Laplace operator, T ₁ and T ₂ are, u is the control input to the controlled object 60 (operation amount), x ₂ =
^{_{x 1 (1), x 2}} (1) = dx 1 (1) is _{^{/ dt = d 2 x 1 /}} dt 2.

[0027]

(Equation 2)

First, a transfer function L / u from the control input u of the control target 60 to the control amount L is expressed by the following equation (3).

[0029]

L / u = [1 / (1 + sT ₁ )] [1 / (1 + sT ₂ )] = 1 / [T ₁ T ₂ s ² + (T ₁ T ₂ ) s + 1] Equation (3)

Now, let the state variable in the transfer function L / u be x
= L, the control amount L is expressed by the following equation (4).
Using the Laplace transform theorem, L ^{(2) that} is second-order differentiated with respect to time t is expressed by the following equation (7) by L ⁽¹⁾ that differentiates control amount L with respect to time and control input u. .

[0031]

X = L = u / [T ₁ T ₂ s ² + (T ₁ + T ₂ ) s + 1] Equation (4)

L ⁽¹⁾ = s · u / [T ₁ T ₂ s ² + (T ₁ + T ₂ ) s + 1] (5)

U = L [T ₁ T ₂ s ² + (T ₁ + T ₂ ) s + 1] Equation (6)

[Equation 7] ^{L (2) = s 2 ·} u / [T 1 T 2 s 2 + (T 1 + T 2) s + 1) = (T 1 T 2 s 2 + (T 1 + T 2) s + 1) / (T ₁ T ₂ ) ・ u / T ₁ T ₂ s ² + (T ₁ + T ₂ ) s + 1-(T ₁ + T ₂ ) / (T ₁ T ₂ ) ・ s ・ u / T ₁ T ₂ s ² + (T _{1 + T 2) s + 1 -} [1 / (T 1 T 2)] · u / [T 1 T 2 s 2 + (T 1 + T 2) s + 1 = - [(T 1 + T 2) / (T 1 T 2)] L ⁽¹⁾ −L / (T ₁ T ₂ ) + u / (T ₁ T ₂ ) Equation (7)

[0032] Then the state variables x ₁ when the state variable x is changed, is represented by x ₁ = L ^* -L, the derivative with respect to time t x ₁ ⁽¹⁾ is x ₁ represented by the following formula (8) It is. Furthermore, x ₁
Let ⁽¹⁾ be a state variable x ₂ and this state variable x ₂ be the time t
X ₂ ⁽¹⁾ differentiated with respect to is expressed by the following equation (9) from the equation (7). Therefore, it can be seen from the equations (8) and (9) that the equation (2) represents the error system.

[0033]

X ₁ ⁽¹⁾ = − L ⁽¹⁾ = x ₂ Equation (8)

X ₂ ⁽¹⁾ = − L ⁽²⁾ = (T ₁ + T ₂ ) / (T ₁ T ₂ )] · L ⁽¹⁾ + L (T ₁ T ₂ ) −u / (T ₁ T ₂₎ ) = − (T ₁ + T ₂ ) / (T ₁ T ₂ )] · x ₂ − (x ₁ −L ^* ) / (T ₁ T ₂ ) −u / (T ₁ T ₂ ) Equation (9)

FIG. 4 shows an example in which the control target 60 in FIG. 3 is replaced by an error system represented by the above equation (2).

<Restriction in Sliding Mode Control> Next, the following equation (1) representing the sliding mode control.
think about. Differential sliding line constant S ⁽¹⁾
When calculating x, use x ₂ = x ₁ ⁽¹⁾ = S−c · x ₁ ,
Assuming that u = Φ · x ₁ + K _f · sign as the control input u
When (S) is substituted, the following equation (10) is obtained using equation (2) of the error system.

[0036]

S ⁽¹⁾ = c · x ₁ ⁽¹⁾ + x ₁ ⁽²⁾ = c · x ₁ ⁽¹⁾ + x ₂ ⁽¹⁾ = c · x ₂ − (T ₁ + T ₂ ) / (T ₁ ) _{+ T 2) · x 2 -} (x 1 -L *) / (T 1 T 2) - [Φ · x 1 + K f · sign (S)] / (T 1 T 2) = [c- (T 1 + T ₂ ) / (T ₁ + T ₂ ) (S−c · x ₁ ) − (x ₁ −L ^* ) / (T ₁ T ₂ ) − [Φ × x ₁ + K _f · sign (S)] / (T ₁ T ₂ ) = S [c− (T ₁ + T ₂ ) / (T ₁ T ₂ ) −x ₁ [c ² −c (T ₁ + T ₂ ) / (T ₁ T ₂ ) + 1 / (T ₁ T ₂ ) + Φ / (T ₁ T ₂ )] − [K _f · sign (S) −L ^* ] / (T ₁ T ₂ ) Equation (10)

Therefore, S · S ⁽¹⁾ is given by the following equation (11).

[0038]

S · S ⁽¹⁾ = S ² [c− (T ₁ + T ₂ ) / (T ₁ T ₂ ) −x ₁ · S c ² −c (T ₁ + T ₂ ) / (T ₁ T ₂ ) + 1 / (T ₁ T ₂ ) + Φ / (T ₁ T ₂ ) −SK _f · sign (S) −L ^* ] (11)

To satisfy the condition of S · S ⁽¹⁾ <0,
From the equation (11), it suffices to satisfy the following conditions. c <(T ₁ + T ₂ ) / (T ₁ T ₂ ). When x ₁ · S> 0, Φ = α> c (T ₁ + T ₂ ) −
It is T ₁ T ^₂ c ₂ -1. When x ₁ · S <0, Φ = β <c (T ₁ + T ₂ ) −
It is T ₁ T ^₂ c ₂ -1. _{^{K f> | L * | max}} , i.e. a dither signal value K _f is larger than the maximum value in the absolute value of the control command L ^*. In the case of S> 0 is a _{K f · sign (S) =} + K f,
Be _{K f - K f · sign (} S) = in the case of S <0.

<Problems and Countermeasures When u = Φ · x ₁ + K _f · sign (S)> If only Φ · x ₁ + K _f · sign (S) is the control input u to the controlled object 60, sliding Since the gain Φ switches between α and β depending on the sign of the mode control state x ₁ · S, chattering occurs. Further, the dither signal value K _f for disturbance suppression is for switching the sign of the sliding line constant S positive and negative (+ K _f and -K _f), chattering is increased. Since K _f > | L ^* | _max , this tendency is strong.

Therefore, occurrence of chattering is suppressed by the following measures (i) to (iii). (I) The control command L ^* is added to the manipulated variable (control input) in a feed-forward manner, and u _B = Φ · x ₁ + K _f · sign
Let (S) + L ^* be the basic manipulated variable. As a result, the third term on the right side of the equation (11) becomes only -S · K _f · sign (S), and K _f may be a small value _satisfying K _f > 0.
Chatter is reduced. (Ii) Further, the basic operation amount u _B is subjected to a first-order lag filter process to obtain a final operation amount u. This makes difficult to change the operation amount u to the code changes in the switching and dither signal value K _f of the gain [Phi, chattering further relaxation. (iii) Further, when the absolute value of the control deviation x ₁ (= L ^* −L) is smaller than the predetermined allowable error e _min , the dither signal value K _{f is set} to K
Change from _f > 0 to _Kf = 0. Thereby, chattering in the vicinity of the stable state (0, 0) on the phase plane shown in FIG. 2 is further reduced.

[0042] The sliding line constants S described previously ^{_{<S = x 1 (1)}} + 2ξω n x 1 + ω n 2 ∫x 1 principle of the sliding mode control _{to> S = c · x 1 +} x 1 (1) and With this control, when K _f = 0, a steady-state deviation of T ₁ T ₂ / (1 + Φ) occurs. That is, the control deviation x with respect to the disturbance f _d
1 (= L ^* -L), when the e = x _1, from equation (2) of the error system, the following derivation process, the following equation (14)
Is represented by Where u = Φ · e + K _f · sign (S) +
L ^* , lower case s is Laplace operator, e ⁽¹⁾ = se, e
⁽²⁾ = s ² e.

[0043]

E ⁽²⁾ = − (T ₁ + T ₂ ) / (T ₁ T ₂ ) e ⁽¹⁾ −1 / (T ₁ T ₂ ) e−1 / (T ₁ T ₂ ) u + 1 / (T ₁ T ₂ ) L ^* + f _d ...... Equation (12)

[Equation 13] e [s ² + s (T ₁ + T ₂ ) / (T ₁ T ₂ ) + 1 / (T ₁ T ₂ ) = − 1 / (T ₁ T ₂ ) (Φ · e + K _f · sign (S) + L ^* ) + 1 / (T ₁ T ₂ ) L ^* + f _d Equation (13)

E = −K _f · sign (S) / (T ₁ T ₂ ) + f _d / s ² + s (T ₁ + T ₂ ) / (T ₁ T ₂ ) + (1 + Φ) / (T ₁ T ₂ ) ...... Equation (14)

In equation (14), if K _f = 0, then
The error with respect to the disturbance f _d is T ₁ T ₂ / (1 + Φ) according to the following equation (15) from the Laplace's final value theorem in consideration of the step-like disturbance f _dm / s. However, the magnitude of the disturbance is standardized and f _dm = 1.

[0045]

(Equation 15)

In order to eliminate the steady-state deviation T ₁ T ₂ / (1 + Φ), a dither signal of ± K _f (K _f > 0) is necessary, which is a factor of the chattering increase as described above.

Therefore, the control deviation x ₁ and its time derivative x ₁
^In addition to ⁽¹⁾ , when an integral deviation ∫x ₁ (= ∫x ₁ dt) obtained by integrating the control deviation x ₁ with respect to time t is introduced, these relationships can be expressed in a three-dimensional phase space as shown in FIG. Can be.

Then, a secondary vibration type is considered in the phase space of FIG.
S = x₁ ⁽¹⁾+ 2ξω_nx₁+ Ω _n ^Two∫x₁The slide
Is detected as a scanning line constant S, and this line is S = x
₁ ⁽¹⁾+ 2ξω_nx₁+ Ω_n ^Two∫x₁Control to go to = 0
Deviation x₁Gain Φ₁And its integral deviation ∫x₁To
Gain Φ_TwoAnd. This produces a dither signal
Value K_fIs K_f= 0, the disturbance f_dSteady bias for
No difference occurs. Below, the reason and the coefficient 2ξω
_nCondition, gain Φ₁And Φ_TwoWill be described.

<2ξω _n , Φ ₁ and Φ ₂ > S · S ^{(1) in the} above-described sliding mode control equation ^{(1)
_{Is, S = x 1 (1)}} + 2ξω n since it is ^{_{x 1 + ω n 2 ∫x 1}} , x 1 (2) = x 2 (1), x 1 (1) = it is x ₂ and Equation Considering (9), the following equation (16) is obtained.

[0050]

[Number 16] ^{S · S (1) = S} · d (x 1 (1) + 2ξω n x 1 + ω n 2 ∫x 1) / dt = S · x 1 (2) + 2ξω n x 1 (1) + ω n ² x ₁ = S-(T ₁ + T ₂ ) / (T ₁ T ₂ ) x ₂ -1 / (T ₁ T ₂ ) x ₁ + 1 / (T ₁ T ₂ ) L ^* -1 / (T ₁ + T ₂ ) u + 2ξω _n x ₂ + ω _n ² x ₁ ] = S ·-(T ₁ + T ₂ ) / (T ₁ T ₂ ) x ₂ + 2ξω _n x ₂ −1 / (T ₁ T ₂ ) x _{^{1 + ω n 2 x 1 -}} 1 / (T 1 T 2) u + 1 / (T 1 T 2) L *] ...... formula (16)

The equation (16) is calculated as follows: x ₂ = S− ₂ nω _n x ₁ −ω
_n ² ∫x ₁ (= x ₁ ⁽¹⁾ ), and u = Φ ₁ ·
Considering x ₁ + Φ ₂ · ∫x ₁ + K _f · sign (S) + L ^* , the following equation (17) is obtained. Note that L ^* is ^calculated by the equation (16).
The operation amount u is added to compensate for the term [1 / (T ₁ T ₂ )] L ^{* in} the feedforward manner.

[0052]

S ⁽¹⁾ = S · − (T ₁ + T ₂ ) / (T ₁ T ₂ ) + 2ξω _n (S−2ξω _n x ₁ −ω _n ² ∫x ₁ ) + − 1 / ( T ₁ T ₂ ) + ω _n ² x ₁ −1 / (T ₁ T ₂ ) u + 1 / (T ₁ T ₂ ) L ^* ] = S · − (T ₁ + T ₂ ) / (T ₁ T ₂ ) + 2ξω _n (S−2ξω _n x ₁ −ω _n ² ∫x ₁ ) + − 1 / (T ₁ T ₂ ) + ω _n ² x ₁ −1 / (T ₁ T ₂ ) (Φ ₁ × ₁ + Φ ₂・ ∫ x ₁ + K _f · sign (S) + L ^* ) + 1 / (T ₁ T ₂ ) L ^* = [− (T ₁ + T ₂ ) / (T ₁ + T ₂ ) + 2ξω _n S ² + − (T ₁ + T ₂ ) / (T ₁ T ₂ ) + 2ξω _n (−2ξω _n ) + − 1 / (T ₁ T ₂ ) + ω _n ² −Φ ₁ / (T ₁ T ₂ ) S · x ₁ + − (T ₁ + T ₂ ) / (T ₁ T ₂ ) + 2ξω _n (−ω _n ² ) −Φ ₂ / (T ₁ T ₂ ) S · ∫x ₁ −K _f · sign (S) / (T ₁ T ₂ ) S …… Equation (17)

From equation (17), in order to satisfy S · S ⁽¹⁾ <0, it suffices that the following condition ⁽¹⁾ is satisfied. From the term of S ² , 2ξω _n <(T ₁ + T ₂ ) / (T
₁ T ₂ ). As long as this holds, ω _n ² is arbitrary. Φ ₁ = α ₁ in the case of than the term of the _{S · x 1 S · x 1} >0>
[(T ₁ + T ₂ ) -2ξω _n T ₁ T ₂ ] 2ξω _n -1 + T ₁ T ₂
ω _n ² . When S · x ₁ <0, Φ ₁ = β ₁ <[(T ₁ + T ₂ )
−2ξω _n T ₁ T ₂ ] 2ξω _n -1 + T ₁ T ₂ ω _n ² . From section S · ∫x _1, in the case of _{S · ∫x 1> 0 Φ 2} =
α ₂ > (T ₁ + T ₂ ) ω _n ² −2 ξω _n ³ T ₁ T ₂ . When S · ∫x ₁ <0, Φ ₂ = β ₂ <[(T ₁ +
T ₂ ) ω _n ² −2 ξω _n ³ T ₁ T ₂ . According to the term of S, when S> 0, K _f · sigh (S)> 0
That is, if + K _f , S <0, then K _f · sign (S) <0, ie, −
K _f . However, if | x ₁ | <e _min when the allowable error is e _min , K _f = 0 may be set.

<Regarding the Steady-State Deviation> The error system of the controlled object 60 when the disturbance f _d is applied is given by the above equation (2).
Since it may be added to the section of the disturbance f _d to be expressed by the following equation (18).

[0055]

(Equation 18)

U = Φ₁・ X₁+ Φ_Two・ ∫x₁+ K_f・ Sign
(S) + L^*And Laplace's theorem,
From the error system of equation (18), the disturbance f_dControl over
Deviation x₁ Is e = x₁Then, through the following derivation process,
It is represented by equation (22).

[0057]

E ⁽²⁾ = − (T ₁ + T ₂ ) / (T ₁ T ₂ ) e ⁽¹⁾ −1 / (T ₁ T ₂ ) e−1 / (T ₁ T ₂ ) u +1 / (T ₁ T ₂ ) L ^* + f _d ...... Equation (19)

[0058]

Es ² + s (T ₁ + T ₂ ) / (T ₁ T ₂ ) + 1 / (T ₁ T ₂ )] = − 1 / (T ₁ T ₂ ) Φ ₁ · e + Φ ₂ · (e / S) + K _f · sign (S) + L ^* ] + 1 / (T ₁ T ₂ ) L ^* + f _d Equation (20)

[0059]

Es ² + s (T ₁ + T ₂ ) / (T ₁ T ₂ ) + 1 / (T ₁ T ₂ ) + Φ ₁ / (T ₁ T ₂ ) + Φ ₂ / (T ₁ T ₂ s) = −1 / (T ₁ + T ₂ ) K _f · sign (S) + f _d Equation (21)

[0060]

E = −K _f · sign (S) / (T ₁ T ₂ ) + f _d / s ² + s (T ₁ + T ₂ ) / (T ₁ T ₂ ) + (1 + Φ ₁ ) / (T ₁ T ₂ ) + Φ ₂ / (T ₁ T ₂ s) ...... Equation (22)

Assuming that K _f = 0 in the equation (22), the error e with respect to the disturbance f _d is given by the following equation (23). Therefore, the error e with respect to the step disturbance f _dm / s becomes zero from the following equation (24) by the Laplace's last theorem, and no steady-state error occurs due to the disturbance. However, the magnitude of the disturbance is standardized and f _dm = 1.

[0062]

E / f _d = s / s ² + s (T ₁ + T ₂ ) / (T ₁ T ₂ ) + (1 + Φ ₁ ) / (T ₁ T ₂ ) + Φ ₂ / (T ₁ T ₂ s) …… Equation (23)

[0063]

(Equation 24)

[0064]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an engine control device according to the present invention will be described in detail with reference to the drawings.

<First Embodiment> With reference to FIG. 1, as a first embodiment of the present invention, a configuration of an engine control apparatus in which S = c × x ₁ + x ₁ ⁽¹⁾ is set as a sliding constant S will be described. In FIG. 1, an engine control device 1 includes a torque deviation calculation unit 2, a sliding line constant calculation unit 3, a gain unit 7, a dither signal value variable switching unit 11, and an addition unit 12.
And a filter unit 13. Further, the calculation section 3 includes a coefficient multiplication section 4, a differentiation calculation section 5, and an addition section 6. Also,
The gain unit 7 includes a calculation unit 8 for gain switching determination data, a gain switching unit 9, and a multiplication unit 10. Each of these parts 2
13 can be realized by a computer and its software.

The control target 60 is shown in detail in FIG. 11, and includes a throttle actuator 70 and an engine 80. The throttle actuator 70 is simulated by a first-order lag system, and has 1 / (1 + sT ₁ ) as a transfer function.
The engine 80 was also simulated with a first-order lag system, and 1 / (1 + s
T ₂ ). Here, s is a Laplace operator, and T ₁ and T ₂ are time constants.

In FIG. 1, the operation unit 2 includes a torque command T _or
^* And the deviation x ₁ of the current torque T _or seek ^{_{(= T or * -T or)}} , arithmetic unit 3 of the sliding line constants, gain unit 7, giving respectively the switching unit 11 and the adding unit 12 of the dither signal value. The torque command T _or ^* is given from outside such as a computer used in the engine test apparatus. Current torque T _or the torque detector 54 shown in FIG. 11
And so on.

The calculation unit 3 calculates the torque deviation x ₁ (= T _or ^* −
From T _or), determine the sliding line constant S by _{S = c · x 1 + x} 1 (1) consisting operation, provided to the variable switching unit 9 of the gain section 7 and a dither signal value. Where x ₂ =
x ₁ ⁽¹⁾ , that is, x ₂ is a differential torque deviation (x ₂ = x ₁ ⁽¹⁾ = dx ₁ / dt) obtained by differentiating x ₁ with respect to time t. c is a coefficient, and the time constants T ₁ and T _{2 of the} control target 60
Is set in the range of 0 <c <(T ₁ + T ₂ ) / (T ₁ + T ₂ ).

For the above operation, the operation unit 3 includes a multiplication unit
4, the differential operation unit 5, and the addition unit 6 operate as follows.
You. The multiplication unit 4 calculates the torque deviation x₁Multiplied by the coefficient c
₁And the differential operation unit 5 calculates s / (1 + sT_Three) Become transmission
Torque deviation x by function₁And its differential torque deviation x₁
⁽¹⁾Are added by the adder 6 to obtain the sliding
Grine constant S (= c · x₁+ X₁ ⁽¹⁾). What
Contact, s is Laplace operator, T_Three Is a time constant.

The gain section 7 has a sliding line constant S
And torque deviation x₁Product S · x₁And this value is gay
S · x₁Gain> 0
Let Φ be Φ = α> c (T₁+ T_Two) -T₁T_Twoc^TwoAs -1
Luc deviation x₁Multiplied by S x₁ If <0, the gain Φ
Φ = β <c (T₁+ T_Two) + T₁T_Twoc^TwoTorque as -1
Deviation x₁And Φ · x₁Is added as one of the manipulated variables
To the part 12.

In the gain section 7, the operation section 8, the gain switching section 9, and the multiplication section 10 operate as follows for the above-described operation. Computing unit 8, sliding line constant S by the torque deviation ^{_{x 1 (= T or * -T}} or) performs a calculation of multiplying a, gives the resulting product x ₁ · S to gain switcher 9 as a gain switching determination data. The gain switching unit 9 determines the sign of the gain switching determination data x ₁ · S, and when x ₁ · S> 0, Φ = α> c (T ₁ + T ₂ ) −T ₁ T ₂ c ² −1, x ₁ · S
In the case of <0, the value of the gain Φ is switched to Φ = β <c (T ₁ + T ₂ ) −T ₁ T ₂ c ² −1 and provided to the multiplication unit 10. x ₁
When S = 0, either α or β may be used, but it is preferable to keep the previous value. The sampling time has a hysteresis element for digital control. The multiplication unit 10 calculates the gain Φ (= α or β) by the torque deviation x ₁ (= T _or ^* −T
_or ) and Φ · x ₁ as _one of the manipulated variables.
Give to 2.

The variable dither signal value switching section 11 basically has a sliding line constant S (= c.x ₁ + x ₁ ⁽¹⁾ ).
The value of the dither signal is changed to + K _f or −K _f (K
_f > 0), and gives K _f · sign (S) to the adding unit 12 as one of the manipulated variables. However, it is determined whether or not the absolute value | x ₁ | of the torque deviation x ₁ is smaller than a predetermined allowable range e _min by comparing x ₁ with e _min and | x ₁ | <e
_min, that is, in the case of −e _min <x ₁ <e _min , K _f = 0 is changed. That is, the dither signal is not substantially output to the adder 12. Here, K _f · sign (S)
Needless to say, when S> 0, + K _f and S <
In the case of 0 is -K _f. When S = 0, + K _f , −K _f
May be taken, but it is preferable to keep the previous sign. The sampling time has a hysteresis element for digital control.

The adder 12 calculates Φ · x ₁ and K _f · sign
(S) and the first basic manipulated variable (= Φ · x ₁ + K _f
Sign (S)), and further adds the torque command T _or ^* in a feed-forward manner to obtain Φ · x ₁ + K _f · sign (S) + T
The _or ^* a second basic manipulated variable u _B, giving the filter unit 13.

The filter unit 1 sets the second basic manipulated variable u _B to 1
First-order lag filter processing is performed by a transfer function of / (1 + sT ₄ ), and as a result, u is given to the throttle actuator 70 of the control target 60 through a driver as a final operation amount, and the motor is driven. Incidentally, s is the time constant Laplace operator, T ₄ is.

In the engine control apparatus 1 of the first embodiment (FIG. 1) described above, basically, the sliding line constant S is calculated based on the torque deviation x ₁ , its time derivative x ₁ ^(1), and the coefficient c. = C · x ₁ + x ₁ ⁽¹⁾
The gain Φ with respect to the torque deviation x ₁ switchable between α and β in accordance with the _first sign of the product S · x _1, also a dither signal according to the sign of S K _f · sign (S) ie K _f It switched between the -K _f. At that time, the way to push adding torque deviation x ₁ in the feedforward manipulated variable u by adding section 12, it is possible to reduce the dither signal value K _f. Therefore, chattering due to switching of the sign of the dither signal is reduced. Further, by performing a first-order lag filtering process on the operation amount u by the filter unit 13, a sudden change in the control input to the control target 60 with respect to the gain switching and the sign switching of the dither signal is suppressed. Accordingly, chattering due to these is reduced. Further, the variable switching unit 11 of the dither signal value | x ₁ | <For e _min dither signal value K _f> vary from 0 to K _f = 0. Therefore,
Within the allowable error e _min , that is, the stable state (0,
In the vicinity of 0), there is no chattering due to the dither signal, and the control response is stabilized.

FIGS. 6 and 7 show the results of the step response of the torque _Tor of the engine control device 1 incorporating the sliding mode control according to the first embodiment. Further, Figure 8 shows the step response results of the torque T _or the engine controller 50 using a conventional PI control for comparison. As can be seen from these figures, a better control response can be obtained in the present invention than in the prior art. However, the conditions are as follows. (I) In FIG. 6, T ₁ = 0.002 sec, T ₂ = 1 sec, T
₄ = 0.05 _{seconds, K f = 0.2, α =} 8~12, β = -
6 to -10 and e _min is 0.78 of the torque command T _or ^* .
%. (Ii) In FIG. 7, T ₁ = 0.002 seconds, T ₂ = 1 second, T ₄
= 0.13 _{seconds, K f = 0.2, α =} 8~12, β = -6
_-10 and e _min is 0.78% of torque command T _or ^*
And (iii) In FIG. 8, T ₂ = 1 second, K _P in PI control,
K _I was set to K _P = 5 and K _I = 5, respectively.

In the above-described first embodiment, the engine control unit 1 uses the torque _Tor as a control amount, and sets the torque command _Tor ^*.
Is used as a control command. If the control amount is a rotation speed or an intake pressure, and the control command is replaced with a rotation speed command or an intake pressure command, the throttle actuator 70 is controlled to control the rotation speed of the engine 80 or the like. The intake pressure can be controlled.

[0078] <Second Embodiment> Next, a second embodiment of the present invention with reference to FIG. ^{_{9, S = x 1 (1}} ) + 2ξω n x 1 + ω n 2
Illustrating the configuration of an engine control apparatus according to sliding line constant ∫x _1. In FIG. 9, an engine control device 21 includes a torque deviation calculation unit 22, a sliding line constant calculation unit 23, a first gain unit 29,
, A dither signal value switching unit 37, and an adding unit 38. Further, the calculation unit 23 includes a differentiation calculation unit 24, a coefficient multiplication unit 25, an integration calculation unit 26, a coefficient multiplication unit 27, and an addition unit 28. Further, the first gain unit 29 is provided with an operation unit 30 for the gain switching determination data.
, A gain switching unit 31, and a multiplication unit 32, and the second gain unit 33 is provided with a gain switching determination data calculation unit 3
4, a gain switching section 35, and a multiplication section 36. Each of these units 22 to 38 can be constituted by a computer and its software.

The control object 60 includes a throttle actuator 70 and an engine 80 as in the first embodiment shown in FIG.
(1 + sT ₁ ), the transfer function of the engine 80 is 1 / (1+
sT ₂ ).

In FIG. 9, the operation unit 22 calculates the torque command T
_or ^* and the deviation x between the current torque T _or which is the controlled variable
^{_{1 (= T or * -T or}} ) the determined, calculation unit 23 of the sliding line constants are given in the first gain portion 29 and the second gain portion 33. The torque command T _or ^* is supplied from the outside such as a computer used in the engine testing apparatus, the torque detector current torque T _or shown in FIG. 11 54
And so on.

The calculation unit 23 calculates the torque deviation x ₁ (= T _or ^* −T
from ^{_{or), S = x 1 (}} 1 as a secondary vibration type) + 2ξω _n x ₁
+ Ω _n ² ∫x ₁ , the sliding line constant S is obtained, and the first gain unit 29 and the second gain unit 33 are calculated.
And a dither signal value switching unit 37. Where x ₁
⁽¹⁾ is a differential torque deviation (= dx ₁ / dt) obtained by differentiating the torque deviation x ₁ with respect to time t, and x _{2 is} also displayed (x ₂ = x ₁ ⁽¹⁾ ). ∫x ₁ is the torque deviation x ₁ time t
And integrated torque deviation (= ∫x ₁ dt). Further, ξ and ω _n are coefficients representing the damping rate (ξ) and speed (ω _n ) of the secondary vibration type, and the time constant T
₁ and T ₂ , 2ξω _n <(T ₁ + T ₂ ) / (T ₁ T ₂ )
Is set within the range that satisfies.

For the above operation, the operation unit 23 of the sliding line constant S includes a differentiation operation unit 24, a coefficient multiplication unit 25, an integration operation unit 26, a coefficient multiplication unit 27, and an addition unit 28. The differential operation unit 24 obtains the differential torque deviation x ₁ ⁽¹⁾ (= x ₂ ) from the torque deviation x ₁ using a transfer function of s / (1 + sT ₃ ). The coefficient multiplying unit 25 obtains 2ξω _n x ₁ by multiplying the torque deviation x ₁ by a coefficient 2ξω _n .
The integral operation unit 26 has 1 / s as a transfer function and has a torque deviation x
Seeking integration torque deviation ∫X ₁ from _1, the coefficient multiplying unit 27 the integral torque deviation ∫x ^{2 ω} _n is multiplied by a coefficient omega _n ² to ₁ ∫X
Seek _1. Adding unit 28 adds them, a sliding line constants ^{_{S S = x 1 (1)}} + 2ξω n x 1 + ω n 2 ∫
determined as x _1.

The first gain unit 29 calculates the torque deviation x ₁ and the sliding line constant S (= x ₁ ⁽¹⁾ + 2ξω _n x ₁ + ω _n
^{2 ∫x} ₁₎ obtains the product x ₁ · S with this value as the gain switching determination data, in the case of x ₁ · S> 0 the gain [Phi ₁ [Phi
₁ = α ₁ > [(T ₁ + T ₂ ) −2ξω _n T ₁ T ₂ ] · 2ξω _n
-1+ (T ₁ T ₂₎ multiplied by the torque deviation x ₁ as omega _n ^2,
When x ₁ · S <0, the gain Φ _{1 is changed} to Φ ₁ = β ₁ <[(T ₁ +
T ₂ ) -2ξω _n T ₁ T ₂ ] · 2ξω _n -1+ (T ₁ T ₂ ) ω _n
^By multiplying the torque deviation x ₁ by ² , Φ ₁ · x ₁ is given to the adding unit 38 as _one of the manipulated variables.

The first gain unit 29
Comprises a gain switching determination data calculation unit 30, a gain switching unit 31, and a multiplication unit 32. That is, the calculation unit 30 calculates the product x ₁ ·· of the torque deviation x ₁ and the sliding line constant S.
S is obtained and given to the gain switching section 31 as gain switching determination data. Gain switcher 31 determines the sign of _{x 1 · S, x 1 ·} S> Gain [Phi ₁ and alpha ₁ if 0
When x ₁ · S <0, the gain Φ ₁ is given to the multiplier 32 as β ₁ . Multiplication unit 32 multiplies the gain [Phi ₁ to the torque deviation _{x 1, Φ 1 · x 1} = α 1 · x 1 or Φ ₁ · x ₁ = β
₁ × ₁ is given to the adding unit 38 as _one of the operation amounts.

Here, α ₁ is α ₁ > [(T ₁ + T ₂ ) −2
ξω _n T ₁ T ₂ ] · 2ξω _n −1+ (T ₁ T ₂ ) ω _n ² . Β ₁ is β ₁ <[(T ₁ + T ₂ ) −
2ξω _n T ₁ T ₂ ] · 2ξω _n -1+ (T ₁ T ₂ ) ω _n ² . When x ₁ · S = 0, either Φ ₁ = α ₁ or Φ ₁ = β ₁ may be used, but it is preferable to keep the previous value. The sampling time for digital control has a hysteresis element.

The second gain section 33 calculates the integrated torque deviation ∫x
₁ and sliding line constant S (= x ₁ ⁽¹⁾ + 2ξω _n
x ₁ + ω _n ² ∫x ₁ ), the value S · と し x ₁ is obtained, and this value is used as gain switching determination data. If S · ∫x ₁ > 0, the gain Φ _{2 is set} to Φ ₂ = α ₂ > [(T ₁ + T ₂ ) ω _n ² -2 ξω _n ³ T ₁
Multiply the torque deviation ∫x ₁ as T ₂ , and if S · ∫x ₁ <0, then multiply the gain Φ ₂ by Φ ₂ = β ₂ <[(T ₁ + T ₂ ) −2ξω _n ³
By multiplying the torque deviation ∫X ₁ as _{T 1 T 2, Φ 2 ·} ∫x 1
Is given to the adding unit 38 as one of the operation amounts.

For the above-described calculation, the second gain unit 33
Comprises a gain switching determination data calculation unit 34, a gain switching unit 35, and a multiplication unit 36. That is, the computing unit 34 calculates the product S · Δx ₁ of the integrated torque deviation Δx ₁ and the sliding line constant S, and gives the result to the gain switching unit 35 as gain switching determination data. The gain switching unit 35 is configured as follows:
The sign of x ₁ is determined, and when S · ∫x ₁ > 0, the gain Φ _{2 is set} to α ₂ , and when S · ∫x ₁ <0, the gain Φ _{2 is set} to β ₂ and given to the multiplier 36. . Multiplying unit 36 multiplies the gain [Phi ₂ in the integral torque deviation _{∫x 1, Φ 2 · ∫x 1} = α 2 ·
∫x ₁ or Φ ₂ · ∫x ₁ = β ₂ · ∫x ₁ is given to the adding unit 38 as _one of the manipulated variables.

Here, α ₂ is α ₂ > (T ₁ + T ₂ ) ω _n ² −
It is set in advance in the range of 2ξω _n ³ T ₁ T ₂ . Β ₂ is set in advance in the range of β ₂ <(T ₁ + T ₂ ) ω _n ² -2ξω _n ³ T ₁ T ₂ . Φ ₂ = α ₂ or Φ when S · ∫x ₁ = 0
₂ = β _{2 It} does not matter which, but it is good to keep the previous value. The sampling time for digital control has a hysteresis element.

The dither signal value switching unit 37 is
Lining constant S (= x₁ ⁽¹⁾+ 2ξω_nx₁+ Ω_n ^Two∫
x₁), The value of the dither signal is set to + K_fOr
-K_f(K _f> 0) and K_f・ Operate sign (S)
This is given to the adding unit 38 as one of the quantities. However, if S> 0
K_f・ Sign (S) = K_f, S <0, K_f・ Sign
(S) =-K_fIt is. + K when S = 0_f, -K_fIzu
It doesn't matter, but it is good to keep the previous sign. What
Sampling time for digital control
It has a cis element.

[0090] adding section 38 and _{Φ 1 · x 1, Φ 2} · ∫x
₁ and K _f · sign (S) are added, and the torque command T _or
^* Is added feed-forward, and as a result u = Φ ₁
x ₁ + Φ ₂ · ∫x ₁ + K _f · sign (S) + T _or ^* is given as an operation amount to the throttle actuator 70 of the control target 60 through an appropriate driver, and the motor is driven.

The engine control of the second embodiment (FIG. 9) described above
In the control device 21, S = x₁ ⁽¹⁾+ 2ξω_nx₁+ Ω_n ^Two∫x₁
To determine the sliding line constant S as
x₁Gain Φ₁Is the product S · x₁Α according to the sign of₁
And β₁And the integrated torque deviation ∫x₁To
Gain Φ_TwoThe product S · ∫x₁Α according to the sign of_TwoWhen
β_TwoAnd the third order shown in FIG.
Original phase space (x₁, X ₁ ⁽¹⁾, ∫x₁) And S = x₁ ⁽¹⁾+2
ξω_nx₁+ Ω_n ^Two∫x₁= Asymptotically low along the 0 line
Control for moving to the fixed state (0, 0, 0) is performed. So
As a result, the dither signal value K_fIs temporarily zero (K_f= 0)
However, no steady-state error occurs due to disturbance. The operation amount u
Torque command T_or ^*Feed-forward
Thus, the dither signal value K_fSo that
In addition, an increase in chattering is suppressed.

In the second embodiment described above, the engine control unit 21 uses the torque T _or as a control amount and _{sets the} torque command T _or.
^* Is a control command, but if the control amount is a rotation speed or an intake pressure, and the control command is correspondingly replaced with a rotation speed command or an intake pressure command, the throttle actuator 70 is controlled to control the rotation speed of the engine 80. And the intake pressure can be controlled.

<Third Embodiment> Next, an engine control device according to a third embodiment of the present invention will be described with reference to FIG.
An engine control device 41 shown in FIG. 10 is obtained by modifying the engine device 21 of the second embodiment shown in FIG. 9 in the following two points. The filter unit 13 is provided on the output side of the adder unit 38 as in the first embodiment of FIG. 1 to reduce the occurrence of chattering. In place of the dither signal value switching unit 37, the same dither signal value variable switching unit 11 as in the first embodiment of FIG. 1 is provided to eliminate the occurrence of chattering due to the dither signal value switching within the allowable error e _min .

Therefore, the engine control device 4 shown in FIG.
The configuration and operation of the first embodiment are clear in the description of the first and second embodiments, but will be described below just in case.

In FIG. 10, an engine control unit 41 includes a torque deviation calculating unit 22, a sliding line constant calculating unit 23, a first gain unit 29, a second gain unit 33, and a variable dither signal value. Switching section 11 and adding section 3
8 and a filter unit 13. Further, the operation unit 2
Reference numeral 3 includes a differential operation unit 24, a coefficient conversion unit 25, an integration operation unit 26, a coefficient multiplication unit 27, and an addition unit 28. The first gain section 29 includes a gain switching determination data calculation section 30, a gain switching section 31, and a multiplication section 32, and the second gain section 33 includes a gain switching determination data calculation section 34. , Gain switching unit 35 and multiplication unit 36
Consists of Each of these units 22 to 38 can be constituted by a computer and its software.

The controlled object 60 includes a throttle actuator 70 and an engine 80, as in the embodiments shown in FIGS.
(1 + sT ₁ ), the transfer function of the engine 80 is 1 / (1+
sT ₂ ).

In FIG. 10, the calculation unit 22 calculates a deviation x ₁ between the torque command _Tor ^* and the current torque _Tor which is a control amount thereof.
(= T _or ^* -T _or) the determined, calculation unit 23 of the sliding line constants are given in the first gain portion 29 and the second gain portion 33. The torque command T _or ^* is supplied from the outside such as a computer used in the engine testing apparatus, the torque detector current torque T _or shown in FIG. 11 54
And so on.

The calculation unit 23 calculates the torque deviation x ₁ (= T _or ^* −T
from ^{_{or), S = x 1 (}} 1 as a secondary vibration type) + 2ξω _n x ₁
+ Ω _n ² ∫x ₁ , the sliding line constant S is obtained, and the first gain unit 29 and the second gain unit 33 are calculated.
And the dither signal value to the variable switching unit 11. here,
x ₁ ⁽¹⁾ is a differential torque deviation (= dx ₁ / dt) obtained by differentiating the torque deviation x ₁ with respect to time t, and x _{2 is} also indicated (x ₂ = x ₁ ⁽¹⁾ ). ∫x ₁ is an integrated torque deviation (= ∫x ₁ dt) obtained by integrating the torque deviation x ₁ with respect to time t. Further, ξ and ω _n are coefficients representing the damping rate (ξ) and speed (ω _n ) of the secondary vibration type, and ₂に よ り ω _n <(T ₁ + T ₂ ) according to the time constants T ₁ and T ₂ of the controlled object 60. ) / (T
It is set in a range that satisfies ₁ T ₂ ).

For the above operation, the operation unit 23 of the sliding line constant S comprises a differentiation operation unit 24, a coefficient multiplication unit 25, an integration operation unit 26, a coefficient multiplication unit 27, and an addition unit 28. The differential operation unit 24 obtains the differential torque deviation x ₁ ⁽¹⁾ (= x ₂ ) from the torque deviation x ₁ using a transfer function of s / (1 + sT ₃ ). The coefficient multiplying unit 25 obtains 2ξω _n x ₁ by multiplying the torque deviation x ₁ by a coefficient 2ξω _n .
The integral operation unit 26 has 1 / s as a transfer function and has a torque deviation x
Seeking integration torque deviation ∫X ₁ from _1, the coefficient multiplying unit 27 the integral torque deviation ∫x ^{2 ω} _n is multiplied by a coefficient omega _n ² to ₁ ∫X
Seek _1. Adding unit 28 adds them, a sliding line constants ^{_{S S = x 1 (1)}} + 2ξω n x 1 + ω n 2 ∫
determined as x _1.

The first gain section 29 calculates the torque deviation x ₁ and the sliding line constant S (= x ₁ ⁽¹⁾ + 2ξω _n x ₁ + ω _n
^{2 ∫x} ₁₎ obtains the product x ₁ · S with this value as the gain switching determination data, the gain [Phi ₁ For x ₁ · S> 0 _{Φ 1}
= Α ₁ > [(T ₁ + T ₂ ) -2ξω _n T ₁ T ₂ ] 2ξω _n -1
+ (T ₁ + T ₂ ) ω _n ² multiplied by the torque deviation x ₁ , x ₁
When S <0, the gain Φ ₁ is increased by Φ ₁ = β ₁ <[(T ₁ +
T ₂ ) −2ξω _n T ₁ T ₂ ] · 2ξω _n -1+ (T ₁ + T ₂ )
By multiplying the torque deviation x ₁ as ω _n ² , Φ ₁ · x ₁ is given to the adding unit 38 as _one of the manipulated variables.

The first gain section 29 is used for the above-described calculation.
Comprises a gain switching determination data calculation unit 30, a gain switching unit 31, and a multiplication unit 32. That is, the calculation unit 30 calculates the product x ₁ ·· of the torque deviation x ₁ and the sliding line constant S.
S is obtained and given to the gain switching section 31 as gain switching determination data. Gain switcher 31 determines the sign of _{x 1 · S, x 1 ·} S> 0 in the case of the gain [Phi ₁ and _{α 1, x 1 · S <} 1 gain [Phi ₁ beta if 0 To the multiplier 32. Multiplication unit 32 multiplies the gain [Phi ₁ to the torque deviation _{x 1, Φ 1 · x 1} = α 1 · x 1 or Φ ₁ · x ₁ = β ₁
X1 is given to the adding unit 38 as _one of the manipulated variables.

Here, α ₁ is α ₁ > [(T ₁ + T ₂ ) −2
ξω _n T ₁ T ₂ ] · 2ξω _n −1+ (T ₁ T ₂ ) ω _n ² . Β ₁ is β ₁ <[(T ₁ + T ₂ ) −
2ξω _n T ₁ T ₂ ] · 2ξω _n -1+ (T ₁ T ₂ ) ω _n ² . When x ₁ · S = 0, either Φ ₁ = α ₁ or Φ ₁ = β ₁ may be used, but it is preferable to keep the previous value. The sampling time has a hysteresis element for digital control.

The second gain section 33 calculates the integrated torque deviation ∫x
₁ and sliding line constant S (= x ₁ ⁽¹⁾ + 2ξω _n
x ₁ + ω _n ² ∫x ₁ ), the value S · と し x ₁ is obtained, and this value is used as gain switching determination data. If S · ∫x ₁ > 0, the gain Φ _{2 is set} to Φ ₂ = α ₂ > (T ₁ + T ₂ ) ω _n ² −2 ξω _n ³ T ₁ T
Multiplying the torque deviation ∫X ₁ as _2, S · ∫x _{1 <2} gains Φ ₂ Φ ₂ = β in the case of _{0 <(T 1 + T 2} ) ω n 2 -2ξω n 3
By multiplying the torque deviation ∫X ₁ as _{T 1 T 2, Φ 2 ·} ∫x 1
Is given to the adding unit 38 as one of the operation amounts.

For the above-described calculation, the second gain unit 33
Comprises a gain switching determination data calculation unit 34, a gain switching unit 35, and a multiplication unit 36. That is, the computing unit 34 calculates the product S · Δx ₁ of the integrated torque deviation Δx ₁ and the sliding line constant S, and gives the result to the gain switching unit 35 as gain switching determination data. The gain switching unit 35 is configured as follows:
The sign of x ₁ is determined. If S · ∫x ₁ > 0, the gain Φ _{2 is set} to α ₂ , and if S · ∫x ₁ <0, the gain Φ ₂
Is given to the multiplication unit 36 as β ₂ . Multiplying unit 36 multiplies the gain [Phi ₂ in the integral torque deviation _{∫x 1, Φ 2 · ∫x 1} = α 2
Of · ∫X ₁ or _{Φ 2 · ∫x 1 = β 2} · ∫x 1 an operation amount 1
And to the adder 38.

Here, α ₂ is α ₂ > (T ₁ + T ₂ ) ω _n ² −
It is set in advance in the range of 2ξω _n ³ T ₁ T ₂ . Β ₂ is set in advance in the range of β ₂ <(T ₁ + T ₂ ) ω _n ³ −2 ξω _n ³ T ₁ T ₂ . Φ ₂ = α ₂ or Φ when S · ∫x ₁ = 0
₂ = β _{2 It} does not matter which, but it is good to keep the previous value. The sampling time has a hysteresis element for digital control.

The variable dither signal value switching section 11 basically has a sliding line constant S (= x ₁ ⁽¹⁾ + 2ξω _n x ₁
+ Switched to the value of the dither signal + K _f or -K _f (K _f> 0), depending on the sign of ω _n ² ∫x _1), to the adder 38 K _f · sign the (S) as one of the control output give. However, it is determined whether or not the absolute value | x ₁ | of the torque deviation x ₁ is less than a preset allowable range e _min by comparing x ₁ and e _min, and | x
₁ | <in the case of e _min namely _{-e m in <x 1 <e} min is, K _f
= 0. That is, the dither signal is not substantially output to the adder 12. Where K _f · sign
Needless to say, (S) means + if S> 0.
In the case of K _f, S <0 is -K _f. + When S = 0
K _f, but may either -K _f, it is preferable to maintain the previous sign. The sampling time has a hysteresis element for digital control.

The adder 38 generates Φ ₁ · x ₁ and Φ ₂ · ∫x
_1, and K _f · sign (S) first basic manipulated variable by adding the _{(= Φ 1 · x 1 +} Φ 2 · ∫x 1 + K f · sign (S)), further the torque command T _or ^* Are added in a feedforward manner,
Φ ₁ · x ₁ + Φ ₂ · ∫x ₁ + K _f · sign (S) + T _or ^* is given to the filter unit 13 as a second basic manipulated variable u _B.

The filter unit 13 performs a first-order lag filter process on the second basic operation amount u _B by using a transfer function of 1 / (1 + sT ₄ ), and as a result, sets u as a final operation amount and appropriately controls the control target 60 through a driver. , And drives the motor. Incidentally, s is the time constant Laplace operator, T ₄ is.

The engine of the third embodiment (FIG. 10) described above.
In the control device 41, S = x₁ ⁽¹⁾+ 2ξω_nx₁+ Ω_n ^Two∫x
₁To determine the sliding line constant S
Difference x₁ Gain Φ₁Is the product S · x₁According to the sign of
α₁And β₁And the integrated torque deviation ∫x
₁Gain Φ_TwoThe product S · ∫x₁Α according to the sign of
_TwoAnd β_TwoBy switching between the second embodiment and
Similarly, the three-dimensional phase space (x₁,
x₁ ⁽¹⁾, ∫x₁) And S = x₁ ⁽¹⁾+ 2ξω_nx₁+ Ω_n ^Two∫x₁
Asymptotically stable state along the line of = 0 (0,0,0)
Is performed. As a result, the dither signal value
K_fIs temporarily zero (K_f= 0), but steady bias due to disturbance
No difference occurs. In addition, the torque command T_or ^*To
By adding feed forward, dither signal
Signal value K_fAnd reduce chattering
Has been suppressed.

Further, in the engine control unit 41 of the third embodiment, as in the first embodiment, the filter unit 13 performs a first-order lag filtering process on the operation amount u, thereby switching the gain and the sign of the dither signal. On the other hand, a sudden change in the control input to the control target 60 is suppressed. Accordingly, chattering due to these is reduced. Further, the variable switching unit 11 of the dither signal value | x ₁ | <For e _min dither signal value K _f> vary from 0 to K _f = 0. Therefore, the tolerance e _min in other words a stable state (zero phase space of Fig. 5,
In the vicinity of (0, 0), there is no chattering due to the dither signal, and the control response is stabilized.

In the third embodiment described above, the engine control device 41 uses the torque _Tor as a control amount and _{sets the} torque command _Tor.
^* Is a control command, but if the control amount is a rotation speed or an intake pressure, and the control command is correspondingly replaced with a rotation speed command or an intake pressure command, the throttle actuator 70 is controlled to control the rotation speed of the engine 80. And the intake pressure can be controlled.

[0112]

Since the present invention is an engine control method and apparatus based on sliding mode control, it is possible to control an object including a backlash element and a hysteresis element with a small amount of overshoot and to perform stable control. is there.

In particular, chattering can be suppressed by performing first-order lag filter processing on the operation amount for the control target. Further, since the dither signal added to the operation amount is set to zero according to the control deviation, chattering can be suppressed. Along with the suppression of chattering, it is possible to mitigate adverse effects on control due to aging or failure of a mechanical system included in the control target.

Further, by adding a component proportional to the control deviation to the sliding line constant, a component proportional to the time derivative thereof, and a component proportional to the time integration,
Even if the dither signal is reduced, no steady-state error occurs.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an engine control device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing the principle of sliding mode control.

FIG. 3 is a diagram showing a control target.

FIG. 4 is a block diagram showing an error system to be controlled.

FIG. 5 is a diagram showing the principle of another example of the sliding mode control.

FIG. 6 is a diagram illustrating a control response example according to the first embodiment.

FIG. 7 is a diagram showing another example of a control response according to the first embodiment.

FIG. 8 is a diagram showing a conventional control response example.

FIG. 9 is a diagram showing a configuration of an engine control device according to a second embodiment of the present invention.

FIG. 10 is a diagram showing a configuration of an engine control device according to a third embodiment of the present invention.

FIG. 11 is a diagram showing a configuration of an engine control device according to a conventional example.

FIG. 12 is a block diagram of a conventional control system.

FIG. 13 is a block diagram of a control target in a conventional example.

FIG. 14 is a diagram showing an example of a control response when hysteresis of a wire is large in a conventional example.

FIG. 15 is a diagram showing an example of a control response when hysteresis of a wire is small in a conventional example.

[Explanation of symbols]

 1,21,41 Engine control unit 2,22 Calculation unit for torque deviation 3,23 Calculation unit for sliding line constant 4,25,27 Coefficient calculation unit 5,24 Differential calculation unit 6,28 Addition unit 7,29,33 Gain Units 8, 10, 30, 32, 34, 36 Multiplication units 9, 31, 35 Gain switching unit 11 Dither signal value variable switching unit 12, 38 Addition unit 13 Filter unit 26 Integral operation unit 37 Dither signal value switching unit

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-224425 (JP, A) JP-A-1-100611 (JP, A) JP-A-2-297603 (JP, A) JP-A-6-297 28005 (JP, A) JP-A-63-301303 (JP, A) JP-A-5-134758 (JP, A) JP-A-2-75001 (JP, A) JP-A-7-121209 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F02D 9/00-45/00

Claims (5)

(57) [Claims] 1. An engine control method including a throttle actuator as a control target: variably controlling a gain for control of the control target so that a sliding line constant of the control target becomes zero; Adding a dither signal so as to suppress a steady-state error due to disturbance; and stopping the addition of the dither signal when the control deviation is within an allowable error range. 2. A throttle actuator as a control object.
In the engine control method including : controlling the gain of the controlled object by controlling the gain of the controlled object;
Variable control so that the riding line constant goes to zero
That the sliding line constant is proportional to the control deviation.
Minute, a component proportional to the time derivative of the control deviation, and the control deviation.
A component that is proportional to the time integral of the difference; adding a dither signal to the manipulated variable for the controlled object so as to suppress a steady-state error due to disturbance; (C) stopping; and performing a first-order lag filter process on the operation amount for the control target. 3. An engine control device including a throttle actuator as a control target, wherein the transfer function of the throttle actuator is 1 / (1 + sT ₁ ), the transfer function of the engine is 1 / (1 + sT ₂ ), and c is 0 <c <(T ₁ + T ₂ )
/ (T ₁ T _2), the deviation between the control commands the x ₁ L ^* and the controlled variable L, x ^{_{1 (1)}} the time differential of the deviation x _1, gain Φ for deviations x _1, the alpha alpha> c ( T ₁ + T ₂ ) −T ₁ T ₂ c ² −
1. When β is β <c (T ₁ + T ₂ ) −T ₁ T ₂ c ² −1 and K _f is a dither signal value: A deviation x ₁ between the control command L ^* and the current control amount L is obtained. From the deviation x ₁ and a predetermined coefficient c, S = c · x ₁ + x ₁
⁽¹⁾ means for obtaining a sliding line constant S by the following operation: a product x ₁ · S of the deviation x ₁ and the sliding line constant S
Means for determining the sign of the product x ₁ · S, and setting the gain Φ to a predetermined value α when x ₁ · S> 0, and to a predetermined value β when x ₁ · S <0. Means for switching; gain Φ is multiplied by torque deviation x ₁ , and Φ · x ₁ is _one of the manipulated variables: Judgment of the positive or negative of the sliding line constant S, and K _f when the dither signal value is S> 0 a, switching to -K _f when the S <0, K _f · sign means that one of the operation amount (S) and; control instruction L ^* and the manipulated variable [Phi · x ₁ and K _f · sign (S )
DOO means for determining a basic manipulated variable u _B in consideration of; means a final control u for the basic manipulated variable u controlled object by performing filtering processing of the primary delay to _B; acceptable predetermined and the deviation x ₁ Compare with the error e _min ,
Means for setting the dither signal value _Kf to zero when -e _min <x ₁ <e _min . 4. An engine control device including a throttle actuator as a control target, wherein the transfer function of the throttle actuator is 1 / (1 + sT ₁ ), the transfer function of the engine is 1 / (1 + sT ₂ ), and 2ξω _n is 2ξω _n <(T ₁
+ T ₂ ) / (T ₁ T ₂ ), x ₁ is a control command L ^* and a control amount L
Deviation between, x ₁ ⁽¹⁾ the time differential deviation x _1, the time integral of the deviation x ₁ to ∫x _1, gain [Phi ₁ for deviation x _1, [Phi
₂ the gain for the integral ∫x _1, the _{α 1 α 1> [(T} 1 +
T ₂ ) -2ξω _n T ₁ T ₂ ] 2ξω _n -1 + T ₁ T ₂ ω _n ² , β
₁ is expressed as β ₁ <[(T ₁ + T ₂ ) -2ξω _n T ₁ T ₂ ] 2ξω _n −
1 + T ₁ T ₂ ω _n ² , where α ₂ is α ₂ > (T ₁ + T ₂ ) ω _n ² −2}
_Let ω _n ³ T ₁ T ₂ , β ₂ be β ₂ <(T ₁ + T ₂ ) ω _n ² −2 ξω _n ³
From the deviation x ₁ with a predetermined coefficient 2Kushiomega _n and omega _n ² Prefecture; control instruction L ^* a control amount L and means for determining the deviation x ₁ with: T ₁ T _2, when the K _f is a dither signal value S
^{_{= X 1 (1) + 2ξω}} n x 1 + ω n 2 ∫x 1 becomes operational by obtaining the sliding line constants S means and; deviation x ₁ and the product S · x ₁ with sliding line constant S
Means for determining the sign of the product S · x ₁ , and the gain Φ ₁ is a predetermined value α ₁ when S · x ₁ > 0, and a predetermined value when S · x ₁ <0. means for switching to β ₁ ; gain Φ ₁ is multiplied by deviation x ₁ , and Φ ₁ · x ₁ is manipulated variable 1
Means for bracts: means for determining the product S · ∫x ₁ with integral ∫X ₁ and sliding line constant S of the deviation; determining the sign of the product S · ∫x _1, the gain [Phi ₂ S · ∫
means for switching to a predetermined value α ₂ when x ₁ > 0, and to a predetermined value β ₂ when S · ∫x ₁ <0; multiplying the gain Φ ₂ by the deviation deviation ∫x ₁ , Φ ₂・ ∫x ₁
Means for one of the manipulated variable: determining the sign of sliding line constant S, a dither signal value to a K _f when the S> 0, when the S <0 switched -K _f, K _f · sign Means for setting (S) as one of the manipulated variables; and adding a control command L ^* to the manipulated variables Φ ₁ · x ₁ , Φ ₂ · ∫x ₁ and K _f · sign (S) to perform an operation on the control target. Means for controlling the quantity of the engine. 5. The control command L ^* and the manipulated variables Φ ₁ · x ₁ , Φ ₂ ·
Means the final control on the operation amount ∫X ₁ and K _f · sign (S), which are summed by performing a filtering process of first order lag; a tolerance e _min a predetermined said deviation x ₁ Compare,
5. The engine control apparatus according to claim 4 , further comprising: means for setting the dither signal value _Kf to zero when -e _min <x ₁ <e _min .