JPH07152405A - Control device - Google Patents

Abstract

PURPOSE:To perform the control of a controlled system in accordance with the system state by changing the control parameter in response to the controlled variable set by a control part in a control state of an operating part and setting newly the control parameter at the control part. CONSTITUTION:The control conditions are initialized, and a test signal generating part 12 transmits the test signals which are held for a fixed time for each 20% opening degree. A control part 9 controls the opening degrees of a valve 8. Meanwhile a parameter calculating part 10 calculates an optimum PI control parameter for the control of the part 9 based on the temperature change information acquired from a temperature sensor 7. The PI control parameter is set at a parameter changing part 11. In a control operation mode, the part 11 monitors the output of the part 9. Then the part 11 changes the PI control parameter at the part 9 based on the relation between the valve opening degree and the PI control parameter and with interpolation/extrapolation of these opening degree and parameter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for controlling a non-linear controlled object by control capable of controlling a linear system.

[0002]

2. Description of the Related Art The amount of change to be controlled is measured and detected,
In an automatic control that compares this with a preset target value and uses the difference between the two to automatically perform the correction operation on the amount to be controlled, the controlled object may be a non-linear system. Many. For example, the temperature of the air to be controlled is a non-linear system when the temperature inside the room is controlled by a cooler or the like.
Therefore, in the indoor air conditioning of a building or the like in which air conditioning is controlled by exchanging heat between the air to be air-conditioned and the cooling water or the hot water, PI control or the like capable of linear system control is used.
The PI control parameters are tuned (set) within a range that can be linearly approximated to a certain operating point without complete air conditioning, thereby performing air conditioning control.

FIG. 3 is a block diagram showing a schematic structure of such an air conditioning system. In the figure, 1 is a room to be air-conditioned, 2 is a heat exchanger, 3 is a cold water supply pipe, 4 is an air circulation duct, 5 is an inlet of the air circulation duct, 6 is an outlet of the air circulation duct, and 7 is an outlet. 6 is a temperature sensor installed near 6, 6 is a valve for changing the amount of cold water supplied to the cold water supply pipe 3, and 9 is PI depending on the temperature detected by the temperature sensor 7.
It is a control unit that controls the opening of the valve 8.

The control unit 9 adjusts the opening of the valve 8 so that the preset temperature and the temperature detected by the temperature sensor 7 become the same. The air circulating in the air circulation duct 4 comes into contact with the cooling water supply pipe 3 in the heat exchanger 2 to be cooled. Then, by changing the flow rate of the cooling water in the cooling water supply pipe 3, the degree of cooling (capacity) of the air circulating in the heat exchanger 2 changes. Therefore, by adjusting the opening degree of the valve 8, the temperature of the air passing through the heat exchanger 2 and discharged from the discharge port 6 to the room 1 changes.

Here, the system for controlling the temperature of the indoor air is non-linear. However, in PI control or the like, if the controlled object is not linear, the corresponding control cannot be performed. However, even if the controlled object is a non-linear system, the controlled object can be approximated to a linear system by controlling a part of this system.

For this reason, the control unit 9 sets only a partial region in the vicinity of an operating point of the controlled non-linear system as the control target, and the PI control parameters are tuned and set. For example, the control unit 9 controls the outside air temperature to be 3 during the daytime in summer.
Assuming that the room temperature is set to about 25 ° C at 0 ° C, the PI control parameter is tuned to 25 to 30.
These are set by carrying out at around ℃.

[0007]

Since the conventional configuration is as described above, there is a problem that the control suitable for all environments cannot be performed. In the air conditioning control by heat exchange described above, since the system to be controlled is non-linear as described above,
When the environmental conditions are different, the control amount is different even if the set temperature is the same. For example, the outside air is hot during the day and the sunlight shines through the window.
In order to lower the temperature of 5 ° C. to the set temperature, the control by the control unit 9 such that the opening degree of the valve 8 becomes 80% is suitable.
However, if the same control is performed at night, or if the original temperature is lowered by 5 ° C., the cooling capacity is too high and overshooting or hunting occurs as it is.

For this reason, conventionally, the PI control parameter is set in accordance with the night, and the valve control amount is determined by this, so that the air conditioning is not so effective in the daytime. That is, if the control amount is adjusted to the night environment, for example, as described above, the valve 8
However, if this is performed during the daytime, then the room temperature does not easily reach the set value.

The present invention has been made to solve the above problems, and an object of the present invention is to enable control suitable for the state of the system to be controlled.

[0010]

The control device of the present invention comprises:
An operation unit that changes the state of the control target, a detection unit that detects the state of the control target, and a state detected by the detection unit using preset control parameters so that the preset values are set. A control unit that operates the operation unit to control the control target, a control amount that changes the operation amount of the operation unit within a predetermined range, and a state change of the control target that the detection unit detects as a result of control by this control amount. The parameter calculation unit for calculating the control parameter in the range of the control amount, and the control parameter calculated by the parameter calculation unit are stored, and the stored control parameter is stored in association with the control amount range of the control unit. And a parameter changing unit set in the control unit.

[0011]

The control parameter is changed according to the control amount in the control of the operation unit performed by the control unit, and this is newly set in the control unit.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a configuration when a control device according to an embodiment of the present invention is applied to an air conditioning control system. In the figure, reference numeral 10 indicates control in a predetermined temperature range based on the opening degree of the valve 8 (operation unit) and the control state of the temperature (control target) in the room 1 detected by the temperature sensor 7 (detection unit) at that time. A parameter calculation unit for calculating the control parameter of the unit 9, 11 is a parameter change unit for changing the control parameter of the control unit 9 according to the opening of the valve 8 using the parameter calculated by the parameter calculation unit 10, and 12 is the parameter calculation unit 10 Is a test signal generator that outputs a test temperature signal for calculating parameters, and is otherwise similar to FIG.

The operation of this air conditioning control system will be described below. First, the control conditions are initialized. First, as shown in FIG. 2, the test signal generator 12 sends out a test signal 21 which is held for 20% of opening for a certain period of time to control the opening of the valve 8. At this time, the parameter calculation unit 10 changes the valve opening degree from the 0% state to the 20% state by the input test signal, and maintains the valve opening degree of 20% for a predetermined time.

Then, based on the temperature change information 22 obtained from the temperature sensor 7 during this period, AR model identification or the like is first performed to identify a model approximated to the sum of the first-order lag and the dead time in this step. Then, using the identified model, the optimum PI control parameter in the control of the control unit 9 is calculated by the Chain-Holones-Reswick method (Chen-Hrones-Reswick method).

Then, similarly, the valve opening is changed from 20% to 4
The temperature change information 23 is picked up by setting it to 0% for a predetermined time and the optimum PI control parameter in the control of the control unit 9 is calculated in the same manner as described above. Similarly,
The temperature change information 24, 25 shown in Table 1 below is acquired at the opening of 60% and 80%, respectively, and the PI control parameter in the control unit 9 for each control amount is calculated.

[0016]

As described above, the opening of the valve 8 and the control unit 9
When the PI control parameter in is obtained, it is set in the parameter changing unit 11. With the above, the initial setting of the control condition is completed, and thereafter the control operation is started. During the control operation, the parameter changing unit 11
Changes the PI control parameter in the control unit 9 by monitoring the output of the control unit 9 and using the stored relationship between the valve opening degree and the PI control parameter to interpolate / extrapolate these. I do.

For example, when the control unit 9 is currently controlling the opening of the valve 8 to be 50%, the parameter changing unit 1
1 uses the values shown in Table 1, and the valve opening is 40% and 60%.
The values of P (proportional band) and I (integration time) in% are interpolated, and P at this time is 4.5 and I is 6.5. Then, the parameter changing unit 11 uses this value as the PI of the control unit 9.
Set as a control parameter. The control unit 9 controls the opening degree of the valve 8 so that the temperature information obtained from the temperature sensor 7 is set to the room temperature.

In the above embodiment, the opening of the valve 8 is increased from 0% in 20% steps to calculate the PI control parameter in the control unit 9. However, the opening of the valve 8 is set to 80%. The PI control parameters may be calculated by narrowing the value in 20% steps from%, and the average of these may be used. Further, the step width of the signal generated by the test signal generator 12 may be made smaller. If the step width is small,
More accurate control is possible. In addition, although the above embodiment is directed to the air conditioning in the building and the PI control of the air conditioning, the present invention is not limited to this. Even if the control target is a non-linear system, if the control unit is a control device capable of controlling only a linear system, it is possible to deal with it in the same manner, and the same effect is achieved.

[0020]

As described above, according to the present invention, even when only linear control such as PI control can be performed,
There is an effect that it becomes possible to control the controlled object of the nonlinear system. Therefore, the control of a non-linear system such as air conditioning can be performed using an inexpensive control device.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration when a control device according to an embodiment of the present invention is applied to an air conditioning control system.

FIG. 2 is a waveform diagram showing a state of a test signal output from a test signal generator 12 in FIG.

FIG. 3 is a configuration diagram showing a schematic configuration of an air conditioning system using a conventional control device.

[Explanation of symbols]

 1 room 2 heat exchanger 3 cold water supply pipe 4 air circulation duct 5 intake port 6 exhaust port 7 temperature sensor 8 valve 9 control unit 10 parameter calculation unit 11 parameter change unit 12 test signal generation unit

Claims (1)

[Claims] 1. An operation unit for changing the state of a controlled object, a detection unit for detecting the state of the controlled object, and a preset state for the state detected by the detecting unit using preset control parameters. As a result of control by the control unit that operates the operation unit to control the controlled object so as to have a certain set value, the control amount that changes the operation amount of the operation unit within a predetermined range, and the control by this control amount. A parameter calculation unit that calculates a control parameter in the range of the control amount of the control unit according to a change in the state of the control target detected by the detection unit, and a control parameter stored by the parameter calculation unit, and the control unit And a parameter changing unit that sets the stored control parameters in the control unit in correspondence with the range of the control amount.