JPH0553601A - Electronic governor - Google Patents

Abstract

PURPOSE:To approximate an error to zero without deteriorating the responsiveness. CONSTITUTION:In an automatic control system, a controlled variable is compared with its target value at a comparison part 20. Then a control part 30 produces a control signal to instruct a manipulated variable, and an operating part 40 operates a controlled system 10. A manipulated variable detecting part 50 detects the manipulated variable with which the system 10 works. Then a target value converting part 60 changes the target value of the controlled variable with the output of the part 50.

Description

Detailed Description of the Invention

[0001]

[Industrial application] When the error between the controlled variable of the controlled object and the target value is zero, the manipulated variable is manipulated to a predetermined reference value, and when the error is not zero, the error and the manipulated variable with respect to the above reference value The present invention relates to an electronic governor of a proportional control system which operates so as to have a proportional relationship with displacement.

[0002]

2. Description of the Related Art FIG. 6 shows the relationship between error and displacement in proportional control. As shown in FIG. 6, when the error is zero, the manipulated variable is manipulated to a predetermined reference value, and when the controlled variable deviates from the target value and there is an error, a displacement proportional to the error is given to the manipulated variable. The controlled variable changes toward the target value. However, since the above-mentioned predetermined reference value is a value determined regardless of the load, normally, the error is zero and the displacement is not zero, and the displacement and the error are stable. For example, when the load is large and the control amount decreases when the operation amount is operated to the reference value, the error and the displacement are balanced and stable in the displacement increasing the control amount above the reference displacement. To do. FIG. 7 shows the transient response of the controlled variable. As shown in FIG. 7, the control amount approaches the target value with time, and as described above, it stabilizes with an error corresponding to the magnitude of the load. Moreover, the steady-state error increases with the magnitude of the load.

[0003]

In the case of proportional control, since the error and the displacement of the manipulated variable are proportional to each other, the error usually exists. In order to bring this error close to zero, there is PI (proportional integral) control that integrates the error over time, adds it and the error, and determines the manipulated variable based on the result. However, in the PI control, the error is integrated, so that it takes time and the responsiveness deteriorates.

An object of the present invention is to bring an error close to zero without sacrificing responsiveness.

[0005]

FIG. 1 is a block diagram showing the principle of the present invention. In the figure, 10 is a controlled object, 20 is a comparison unit, 3
0 is an adjustment unit, 40 is an operation unit, 50 is an operation amount detection unit, 60
Represents a target value conversion unit.

The comparison unit 20 compares the control amount of the controlled object 10 with the target value and outputs the error. The adjusting unit 30 issues a control signal instructing the magnitude of the manipulated variable by proportional control according to the error.

The operation unit 40 receives the control signal and operates the controlled object 10. The manipulated variable detector 50 detects the magnitude of the manipulated variable. The target value conversion unit 60 shifts the target value according to the operation amount.

[0008]

The operation amount detection unit 50 detects the operation amount by the control signal output from the adjustment unit 30, the operation amount operated by the operation unit 40, or the physical amount corresponding to the operation amount in the controlled object, and the detected value is sent to the target value conversion unit 60. Tell the operation amount. The target value conversion unit 60 shifts the target value according to the magnitude of the operation amount.

When the control amount is smaller than the original target value, a value larger than the original target value is set as the target value, and conversely, when the control amount is larger than the original target value, it is smaller than the original target value. The value is the target value. As a result, the error between the steady value and the original target value becomes smaller.

[0010]

2 and 3 show embodiments of the present invention. In FIGS. 2 and 3, reference numerals 10, 20, 30, 40 and 50 correspond to those in FIG.

2 and 3 show an engine 11 with a load 12.
1 shows a system for performing control with the control target 10. In the system shown in FIG. 2, the actuator 41 has a position detecting means 50.
The error information received from the comparison unit 20 by the calculation unit 30 (corresponding to the adjustment unit) and the engine 1 are provided by providing the operation amount detection unit.
It corresponds to the throttle position of 1. Further, in this system, the output of the position detecting means 50 is input to the comparing section 20 via the gain 51, and the target value is converted by adding or subtracting it to the original target value.

In the system shown in FIG. 3, the actuator 41 is provided with the spring 14, and the throttle position is determined when the torque of the actuator and the spring are balanced. Further, in this system, the control signal output from the arithmetic unit 30 is transmitted via the position detecting means 50 to the comparison unit 20.
Is input to. Since the control signal corresponds to the throttle position, the comparison unit 20 converts the target value according to the control signal.

FIG. 4 shows an example of the circuit shown in FIG. Reference numerals 13 and 2
0, 30, 41, 50 correspond to FIGS. 1 and 3.
The target value of the controlled variable is input to the point A, and the controlled variable is input to the point B. The control amount input is amplified by the operational amplifier OP3 and input to the operational amplifier OP1 via the resistor R2. When the control amount is smaller than the target value, the output of the operational amplifier OP1 has a negative value and the output of the operational amplifier OP2 has a positive value, so that the output is input to the operational amplifier OP1 via the position detecting means 50. As a result, the target value is converted to a larger value. On the contrary, when the controlled variable is larger than the target value, the target value is converted to a smaller value.

FIG. 5 shows the transient response of the embodiment. Taking the case of an engine as an example, when performing proportional control with a constant number of revolutions, the target value is shifted according to the throttle position corresponding to the magnitude of the load, so the error becomes small.

By the way, when the fine movement of the throttle is reflected in the input of the target value and the system becomes unstable, a low-pass filter may be provided in the throttle position detecting section. Further, even when this is applied to the one including the integral control such as the PI control or the PID (proportional integral derivative) control, the load on the integrating portion for reducing the error is reduced and the responsiveness is improved.

[0016]

According to the present invention, the error can be reduced without sacrificing the responsiveness.

[Brief description of drawings]

FIG. 1 shows a principle configuration diagram of the present invention.

FIG. 2 shows an embodiment of the present invention.

FIG. 3 shows another embodiment of the present invention.

FIG. 4 shows a specific circuit example of a main part in the case of FIG.

FIG. 5 shows the transient response for the present invention.

FIG. 6 is a diagram illustrating an error and a displacement.

FIG. 7 shows a transient response in the conventional case.

[Explanation of symbols]

 10 Control Target 20 Comparing Section 30 Adjusting Section 40 Operating Section 50 Operating Quantity Detection Section 60 Target Value Converting Section

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Claims (2)

[Claims] 1. A comparison unit (20) for comparing a control amount of a controlled object (10) with a target value to obtain an error thereof, and a control signal for instructing a magnitude of an operation amount according to the magnitude of the error. The control unit (30) that emits
An operation unit (40) for applying an operation to (10) is provided, and when the error is zero, the operation amount is operated to a predetermined reference value, and when the error is not zero, the error and the displacement of the operation amount with respect to the reference value are set. In an electronic governor of a proportional control system that operates in a proportional relationship, the manipulated variable detector (50) that detects the magnitude of the manipulated variable and the target that shifts the target value corresponding to the magnitude of the manipulated variable. An electronic governor, characterized in that a value conversion unit (60) is provided to perform the proportional control with the shifted target value. 2. The electronic governor according to claim 1, wherein the manipulated variable detector (50) is provided with a low-pass filter.