JP7190828B2 - Control device, air conditioning system, control method and program - Google Patents

Description

The present invention relates to a control device, an air conditioning system, a control method and a program.

In PID (Proportional-Integral-Differential) control, there is known a technique of tuning control parameters to improve controllability such as responsiveness and stability.

For example, Patent Literature 1 discloses a technique of executing a special operation in which an operation amount is oscillated with a constant amplitude, and tuning a control parameter based on a control amount obtained during the special operation.

JP 2009-151521 A

However, when performing special operation for tuning control parameters, there is a problem that the control amount during special operation differs from the control amount during normal operation.

For example, consider a case in which an air conditioner is controlled by PID control, the blowout temperature is set as a controlled variable, and the set temperature is set as a target value of the controlled variable. In this case, the controlled variable during the special operation, that is, the blowing temperature is different from the set temperature. Therefore, there is a possibility that the comfort of a person in the room to be air-conditioned may be reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a control device and the like that tunes control parameters without performing special operation in view of the above circumstances.

In order to achieve the above object, the control device according to the present invention includes:
A control device for controlling a controlled object by proportional-integral-derivative control using a proportional gain, an integral time, and a derivative time as control parameters ,
a controlled variable acquiring means for acquiring a controlled variable of the controlled object;
target value acquisition means for acquiring a target value of the controlled variable;
an overshoot amount acquiring means for acquiring an overshoot amount of the control amount during start-up operation of the controlled object;
an arrival time acquiring means for acquiring an arrival time from when the controlled object is activated until the controlled variable reaches the target value;
Hunting amount acquisition means for acquiring a hunting amount of the control amount during stable operation of the controlled object;
At least one of: the amount of overshoot is greater than a predetermined upper limit of overshoot; the arrival time is longer than a predetermined target time; and the amount of hunting is greater than a predetermined upper limit of hunting. a tuning means for tuning the control parameters when satisfying
control means for determining a manipulated variable based on the controlled variable, the target value, and the control parameter, and controlling the controlled object based on the manipulated variable;
with
The tuning means adjusts the hunting amount until the hunting amount is greater than the hunting upper limit value and the control amount reaches the target value during the stable operation until the difference between the control amount and the target value becomes equal to the hunting amount. is less than or equal to the threshold, tuning is performed to reduce the proportional gain.

According to the present invention, the control parameters are tuned based on the information during start-up operation and stable operation, that is, during normal operation, so the control parameters can be tuned without special operation.

A diagram showing the configuration of an air conditioning system according to an embodiment of the present invention. 1 is a diagram showing the functional configuration of an air conditioner and an air conditioning control device according to an embodiment of the present invention; 1 is a diagram showing an example of a hardware configuration of an air conditioning control device according to an embodiment of the present invention; FIG. The figure which shows the pattern of the change of the control amount in the air conditioning system which concerns on embodiment of this invention. (a) is a diagram comparing a pattern that does not require tuning and a pattern that requires tuning to reduce the amount of overshoot. (b) is a diagram comparing a pattern that does not require tuning and a pattern that requires tuning to reduce the arrival time. (c) is a diagram comparing a pattern that does not require tuning and a pattern that requires tuning to reduce the amount of overshoot and arrival time. The figure which compared the operation amount at the time of target value attainment, and the operation amount at the time of stability in the air-conditioning system which concerns on embodiment of this invention. (a) is a diagram showing a case where the manipulated variable at the time of reaching the target value is larger than the manipulated variable at the time of stability. (b) is a diagram showing a case where the manipulated variable when reaching the target value is smaller than the manipulated variable when stable; FIG. 4 is a diagram showing the relationship between the amount of overshoot and the rate of change in the air conditioning system according to the embodiment of the present invention; FIG. 4 is a diagram showing the relationship between arrival time and change speed in the air conditioning system according to the embodiment of the present invention; FIG. 4 is a diagram showing the relationship between the amount of hunting and the rate of change in the air conditioning system according to the embodiment of the present invention; 4 is a flow chart showing the operation of starting operation tuning in the air conditioning control device according to the embodiment of the present invention; 4 is a flow chart showing the operation of starting operation tuning in the air conditioning control device according to the embodiment of the present invention; 4 is a flow chart showing the operation of starting operation tuning in the air conditioning control device according to the embodiment of the present invention; 3 is a flow chart showing operation of tuning for stable operation in the air conditioning control device according to the embodiment of the present invention;

Hereinafter, air conditioning systems according to embodiments of the present invention will be described with reference to the drawings. In each drawing, the same code|symbol is attached|subjected to the same or equivalent part.

(Embodiment)
An air conditioning system 1 according to an embodiment will be described with reference to FIG. The air conditioning system 1 is an air conditioning system that employs a water system. The air conditioning system 1 includes a heat source device 2 , a primary pump 3 , a secondary pump 4 , an air conditioner 6 and an air conditioning control device 10 . Also, the primary pump 3 , the heat source device 2 , the secondary pump 4 and the air conditioner 6 are connected by a water pipe 5 . An arrow marked on the water pipe 5 indicates the direction of the water flow. Also, the air conditioning control device 10 is connected to the air conditioner 6 via a communication line.

The heat source machine 2 generates cold water or hot water from water circulated by the primary pump 3 and the secondary pump 4 . The heat source device 2 is, for example, a heat pump type heat source device.

A primary pump 3 and a secondary pump 4 are used to circulate water in the water-based air conditioning system 1 . Note that the secondary pump 4 is not essential.

The air conditioner 6 is, for example, an air conditioner that is installed indoors and air-conditions the room. The air conditioner 6 is, for example, an air handling unit.

The air conditioning control device 10 is a control device that controls the temperature of air blown out from the air conditioner 6 .

The air conditioning system 1 is an example of an air conditioning system according to the present invention. The air conditioner 6 is an example of a controlled object according to the present invention. The air conditioning control device 10 is an example of a control device according to the present invention.

To facilitate understanding, an outline of air conditioning by the air conditioning system 1, an outline of control by the air conditioning control device 10, and an outline of tuning of control parameters by the air conditioning control device 10 will be described below.

Although the details will be described later, as shown in FIG. 2 , the air conditioner 6 includes a cold/hot water coil 61 , a valve 62 , an air blower 63 , and a temperature sensor 64 . Further, the secondary pump 4 and the cold/hot water coil 61, the cold/hot water coil 61 and the valve 62, and the valve 62 and the primary pump 3 are connected by the water pipe 5, respectively.

In the air conditioning system 1, cold water or hot water is generated by the heat source device 2, water is circulated by the primary pump 3 and the secondary pump 4, cold water or hot water is supplied to the cold/hot water coil 61, and air is supplied to the cold/hot water coil 61 by the blower 63. is blown, and the air around the cold/hot water coil 61 is blown out to perform air conditioning. If the water generated by the heat source device 2 is cold water, cooling is performed, and if the water generated by the heat source device 2 is hot water, heating is performed. For the sake of simplicity, the following description assumes that the air conditioning is cooling and that the water generated by the heat source device 2 is cold water.

A temperature sensor 64 detects the blown air temperature, which is the temperature of the blown air. The air conditioning control device 10 changes the amount of water flowing through the cold/hot water coil 61 by controlling the valve 62 . When the amount of water flowing through the cold/hot water coil 61 changes, the temperature of the air around the cold/hot water coil 61 also changes, so the blown air temperature also changes. A target value is set for the blown air temperature, and the air conditioning control device 10 performs control to make the blown air temperature equal to the target value. The air conditioning control device 10 acquires the blowing air temperature detected by the temperature sensor 64 as a control amount, and controls the valve 62 by PID control. At this time, PID control is performed using the degree of opening of the valve 62 as the manipulated variable.

PID control is feedback control based on three control parameters: proportional gain, integral time, and derivative time. If u(t) is the manipulated variable, e(t) is the deviation between the controlled variable and the target value, K is the proportional gain, Ti is the integral time , and Td is the derivative time, then u(t) and e(t ) is given by equation (1). In the following description, it is assumed that differential action has less influence than proportional action and integral action.

The air-conditioning control device 10 determines the manipulated variable from the deviation between the controlled variable and the target value based on Equation (1). As described above, the controlled variable is the blowing air temperature, and the manipulated variable is the opening of the valve 62 .

On the other hand, the control parameters described above are determined based on empirical rules, for example, and may not be appropriate. If the control parameters are not appropriate, for example, the control amount oscillates greatly, resulting in a lack of stability, and it takes a long time for the control amount to reach the target value, resulting in poor responsiveness.

Therefore, the air conditioning control device 10 performs tuning to adjust the above control parameters to more appropriate values. The air conditioning control device 10 can improve control stability and responsiveness by tuning.

Hereinafter, the time from when the air conditioner 6 is started until the control amount reaches the target value for the first time is referred to as an arrival time.

Next, functional configurations of the air conditioner 6 and the air conditioning control device 10 will be described with reference to FIG. It should be noted that, as described above, it is assumed that the air conditioning is cooling, and the water generated by the heat source device 2 is cold water.

As described above, the air conditioner 6 includes the cold/hot water coil 61 , the valve 62 , the blower 63 and the temperature sensor 64 .

Cold water generated by the heat source device 2 flows through the cold/hot water coil 61 . When the cold water flows through the cold/hot water coil 61, the air around the cold/hot water coil 61 is cooled. The amount of water flowing through the cold/hot water coil 61 is adjusted by a valve 62 . As the amount of flowing water increases, the cold water takes more heat from the air around the cold/hot water coil 61, so the temperature of the air around the cold/hot water coil 61 tends to drop.

The opening degree of the valve 62 is adjusted under the control of the air conditioning control device 10 . The valve 62 has an actuator, for example, and the actuator is controlled by an electric signal transmitted from the air conditioning control device 10 to adjust the degree of opening. Hereinafter, these phenomena may simply be described as "the opening degree of the valve 62 is controlled by the air conditioning control device 10".

The blower 63 draws in air from outside the air conditioner 6 and blows it onto the cold/hot water coil 61 . When the air is blown onto the cold/hot water coil 61 , the air around the cold/hot water coil 61 is blown out of the air conditioner 6 through an air outlet (not shown). Since the air around the cold/hot water coil 61 is cooled, it can be said that cooling can be performed by blowing air from the blower 63 .

A temperature sensor 64 detects the blown air temperature. The temperature sensor 64 is provided, for example, near the outlet. The temperature sensor 64 transmits temperature information indicating the detected blown air temperature to the air conditioning control device 10 .

The air conditioning control device 10 includes a controlled variable acquisition section 100 , a storage section 110 , a tuning section 120 and a valve control section 130 . Tuning unit 120 also includes target value acquisition unit 121 , overshoot amount acquisition unit 122 , arrival time acquisition unit 123 , and hunting amount acquisition unit 124 .

The controlled variable acquisition unit 100 acquires the blown air temperature from the temperature sensor 64 of the air conditioner 6 . Since the blown air temperature is a controlled variable in the control of the air conditioning control device 10, it can be said that acquiring the blown air temperature from the temperature sensor 64 is to acquire the controlled variable. Hereinafter, obtaining the blowing air temperature from the temperature sensor 64 may be simply referred to as "obtaining the controlled variable". The controlled variable acquisition unit 100 is an example of controlled variable acquisition means according to the present invention.

In addition, the control amount acquisition unit 100 outputs the acquired control amount to the valve control unit 130 . Since the valve control unit 130 performs PID control based on the deviation between the current control amount and the target value, the valve control unit 130 needs the current control amount.

In addition, the control amount acquisition unit 100 stores the acquired control amount in the storage unit 110 in chronological order in association with the acquisition time. The control variables stored in the storage unit 110 are required when tuning control parameters by the tuning unit 120, which will be described later.

As described above, the control amount acquired by the control amount acquisition unit 100 is stored in the storage unit 110 in chronological order in association with the acquisition time.

Further, the operation amount of the valve control unit 130 is stored in the storage unit 110 in chronological order, as will be described later.

The storage unit 110 also stores a target value of the blowing air temperature. It can also be said that the target value of the blown air temperature is the target value of the control amount. Hereinafter, the target value of the blown air temperature or the target value of the controlled variable may be simply referred to as the target value.

The storage unit 110 also stores a target time value that determines the upper limit of the time from when the air conditioner 6 is started until the controlled variable reaches the target value. This target time is used, for example, when determining the need for tuning. For example, if the time required for the controlled variable to reach the target value after startup is longer than the target time, it may be determined that the responsiveness is poor, and tuning may be performed.

The storage unit 110 also stores an overshoot upper limit value that determines the upper limit of the overshoot amount and a hunting upper limit value that determines the upper limit of the hunting amount. These upper limits are used, for example, when determining the need for tuning. For example, when the overshoot amount exceeds the overshoot upper limit value, or when the hunting amount exceeds the hunting upper limit value, it is considered that the stability is judged to be poor and tuning is performed. In addition, hereinafter, these upper limits may be simply referred to as "upper limits".

The target value, target time, overshoot upper limit value, and hunting upper limit value may be, for example, values determined in advance when the air conditioning control device 10 is shipped, or may be set by the administrator of the air conditioning system 1. may Description and illustration of the configuration for setting the target value, the target time, the overshoot upper limit value, and the hunting upper limit value are omitted.

The storage unit 110 also stores control parameters, that is, values indicating the proportional gain K, the integral time Ti, and the derivative time Td. These control parameters can be updated by tuning by the tuning unit 120, which will be described later. Until tuning is performed, for example, values based on empirical rules are stored in the storage unit 110 as initial values of the control parameters.

The tuning unit 120 acquires the target value acquired by the target value acquisition unit 121, the overshoot amount acquired by the overshoot amount acquisition unit 122, the arrival time acquired by the arrival time acquisition unit 123, and the hunting amount acquisition unit 124. The control parameters stored in the storage unit 110 are tuned based on the hunting amount obtained and the operation amount stored in the storage unit 110 . After tuning the control parameters, the tuning unit 120 updates each parameter stored in the storage unit 110 to the value after tuning. Details of tuning will be described later. The tuning section 120 is an example of tuning means according to the present invention.

The amount of overshoot and the arrival time are the values during start-up operation, while the amount of hunting is the value during stable operation. Here, the start-up operation is the operation from when the air conditioner 6 is started to when it stabilizes. The stable time is when the change in the control amount is stable, such as when the control amount does not change, or when the control amount changes but the change is roughly periodic. Stable operation is the operation of the air conditioner 6 during stable operation. For example, start-up operation cannot be said to be stable operation. Moreover, even if the operation is not start-up operation, operation when the change in the control amount is not stable, such as immediately after tuning or immediately after the occurrence of a large disturbance, cannot be said to be stable operation.

The target value acquisition unit 121 acquires target values stored in the storage unit 110 . The target value acquiring unit 121 is an example of target value acquiring means according to the present invention.

The overshoot amount acquisition unit 122 acquires the overshoot amount based on the target value acquired by the target value acquisition unit 121 and the control amount stored in the storage unit 110 in time series. In the present embodiment, the overshoot amount is an amount indicating how much the control amount exceeds the maximum after the control amount reaches the target value for the first time after the air conditioner 6 is started. The overshoot amount acquisition unit 122 is an example of overshoot amount acquisition means according to the present invention.

The arrival time acquisition unit 123 acquires the arrival time based on the target value acquired by the target value acquisition unit 121 and the control amount stored in the storage unit 110 in time series. Since the time when the controlled variable reaches the target value for the first time can be known from the controlled variable and the acquisition time stored in the storage unit 110, the difference between this time and the startup time of the air conditioner 6 is the arrival time. The arrival time obtaining unit 123 is an example of the arrival time obtaining means according to the present invention.

The hunting amount acquisition unit 124 acquires the hunting amount during stable operation of the air conditioner 6 based on the control amount stored in the storage unit 110 in time series. In the present embodiment, the hunting amount is an amount indicating how much the controlled variable exceeds the target value after the controlled variable reaches the target value during stable operation. The hunting amount acquisition unit 124 also acquires the time from when the controlled variable reaches the target value to when the difference between the controlled variable and the target value becomes equal to the hunting amount during stable operation. The hunting amount acquisition unit 124 is an example of hunting amount acquisition means according to the present invention.

The valve control unit 130 determines the opening degree of the valve 62 based on the current control amount acquired by the control amount acquiring unit 100, the target value stored in the storage unit 110, and the control parameter stored in the storage unit 110. is the manipulated variable, and PID control is performed. The valve control unit 130 acquires the current controlled variable from the controlled variable acquisition unit 100 . Valve control unit 130 acquires the target value from storage unit 110 . Valve control unit 130 acquires control parameters from storage unit 110 . The valve control unit 130 calculates the manipulated variable by equation (1) based on the deviation e(t) between the current controlled variable and the target value, and the proportional gain K, the integral time Ti, and the derivative time Td, which are control parameters. Determine u(t). The valve control unit 130 controls the air conditioner 6 as a control target by adjusting the opening degree of the valve 62 based on the manipulated variable u(t). Valve control unit 130 is an example of control means according to the present invention.

Further, the valve control unit 130 associates the current operation amount with the current time and stores it in the storage unit 110 in chronological order.

Next, an example of the hardware configuration of the air conditioning control device 10 will be described with reference to FIG. 3 . The air conditioning control device 10 shown in FIG. 3 is implemented by a computer such as a personal computer or a microcontroller.

Air conditioning control device 10 includes processor 1001 , memory 1002 , interface 1003 , and secondary storage device 1004 , which are interconnected via bus 1000 .

The processor 1001 is, for example, a CPU (Central Processing Unit). Each function of the air conditioning control device 10 is realized by the processor 1001 reading the dedicated program stored in the secondary storage device 1004 into the memory 1002 and executing the program.

The memory 1002 is, for example, a main memory configured by RAM (Random Access Memory). The memory 1002 stores a dedicated program read by the processor 1001 from the secondary storage device 1004 . The memory 1002 also functions as a work memory when the processor 1001 executes the dedicated program.

The interface 1003 is an I/O (Input/Output) port such as a serial port or a USB (Universal Serial Bus) port. By connecting the temperature sensor 64 to the interface 1003, the function of the controlled variable acquisition unit 100 is realized, and by connecting the valve 62 to the interface 1003, the function of the valve control unit 130 is realized.

The secondary storage device 1004 is, for example, a flash memory, HDD (Hard Disk Drive), SSD (Solid State Drive). A secondary storage device 1004 stores a dedicated program executed by the processor 1001 . Also, the function of the storage unit x is realized by the secondary storage device 1004 .

In the hardware configuration shown in FIG. 3, the air conditioning control device 10 has a secondary storage device 1004 . However, the configuration is not limited to this, and the secondary storage device 1004 may be provided outside the air conditioning control device 10 and the air conditioning control device 10 and the secondary storage device 1004 may be connected via the interface 1003 . In this form, removable media such as USB flash drives, memory cards, etc. can also be used as the secondary storage device 1004 .

Further, instead of the hardware configuration shown in FIG. 3, the air conditioning control device 10 may be configured with a dedicated circuit using an ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), or the like. good. Moreover, in the hardware configuration shown in FIG. 3, part of the functions of the air conditioning control device 10 may be implemented by a dedicated circuit connected to the interface 1003, for example. For example, among the functions of the air conditioning control device 10, the function of the tuning unit 120 and the function of the storage unit 110 may be implemented by a computer, and the other functions may be implemented by dedicated circuits.

Next, referring to FIGS. 4(a), 4(b), and 4(c), tuning based on changes in the control amount during start-up operation will be described. 4(a), 4(b), and 4(c) are diagrams comparing time-series changes in the control amount between cases in which tuning is not required and cases in which tuning is required.

In all of FIGS. 4A, 4B, and 4C, the solid line graph indicated by (a) shows changes in the controlled variable when tuning is unnecessary. This change is hereinafter referred to as "pattern (a)". Graphs indicated by dotted lines (a), (c), and (d), dashed-dotted lines, and broken lines indicate changes in the control amount when tuning is necessary. These changes are hereinafter referred to as "pattern (a)," "pattern (c)," and "pattern (d)," respectively.

In pattern (a), the arrival time is equal to or less than the target time t_lim, and the overshoot amount is equal to or less than the overshoot upper limit value Ov_lim. In this case, it can be said that the control in pattern (a) has good responsiveness and stability, so tuning is unnecessary.

In pattern (b) shown in FIG. 4(a), the arrival time is equal to or less than the target time t_lim, but the overshoot amount is greater than the upper limit value Ov_lim. Therefore, since it can be said that the stability is lacking, tuning is required to keep the overshoot amount below the upper limit value Ov_lim.

In this case, as shown in FIGS. 5(a) and 5(b), there are two cases according to the magnitude relationship between the manipulated variable Mv0 at the time of reaching the target value and the manipulated variable Mv1 at the time of stability. In the case shown in FIG. 5(a), that is, when Mv0 is greater than Mv1, it is considered that a large overshoot occurs due to excessive integral action. Therefore, tuning should be performed to weaken the integral action, that is, to lengthen the integral time.

Here are some specific examples. It is considered that if the manipulated variable becomes equal to Mv1 when the target value is reached, it will remain stable and no overshoot will occur. Therefore, it is conceivable to perform tuning so that the manipulated variable at the time of reaching the target value is equal to Mv1.

Let the initial deviation be e0, the arrival time t0, the integration time before tuning Ti0, and the integration time after tuning Ti1. ) holds. As described above, since the influence of the differential action is smaller than that of the proportional action and the integral action, the differential action is assumed to be 0 below.
K/Ti0×1/2×e0×t0=Mv0 Formula (2)
K/Ti1×1/2×e0×t0=Mv1 Formula (3)

Equation (4) holds from equations (2) and (3).
Ti1=Mv0/Mv1 Formula (4)

Therefore, in pattern (b), when Mv0 is greater than Mv1, the integration time Ti1 may be tuned based on equation (4), for example.

Next, the case shown in FIG. 5B, that is, the case where Mv0 is less than or equal to Mv1 will be described. In this case, it is considered that a large overshoot occurs because the proportional action is too strong. Therefore, in this case, it is necessary to perform tuning to weaken the proportional action, that is, to reduce the proportional gain. However, if the proportional gain is decreased, the integral action also decreases, so it is preferable to tune the integral time after tuning the proportional gain.

A specific example will be described with reference to FIG. First, the average change speed a of the deviation from the time of startup until the time Ta until the overshoot amount reaches the maximum value Ov is obtained by equation (5).
a=(e0+Ov)/Ta Equation (5)

Next, consider the change speed b at which the amount of overshoot is equal to or less than Ov_lim. Also, let Tb be the time when the amount of overshoot is equal to Ov_lim. In the graph of FIG. 6, the change speed a corresponds to the line segment connecting the coordinates (0, e0) and the coordinates (Ta, -Ov), and the change speed b corresponds to the coordinates (0, e0) and the coordinates (Tb, -Ov_lim). ) corresponds to the line segment connecting Tb that makes the lengths of these line segments equal is obtained based on equation (6). This corresponds to performing tuning while the change distance of the control amount is the same.
Ta ² +(e0+Ov) ² =Tb ² +(e0+Ov_lim) ² Formula (6)

Then, the change speed b is obtained from the equation (7).
b=(e0+Ov_lim)/Tb Formula (7)

Assuming that the proportional gain before tuning is K0 and the proportional gain after tuning is K1, K1 can be obtained from equation (8).
K1=K0×b/a Formula (8)

Next, the integration time Ti is also tuned. As in the case where Mv0 is greater than Mv1, tuning is performed so that the manipulated variable when reaching the target value is equal to the manipulated variable Mv1 when stable. Note that equation (9) holds when the target value reaching time before proportional gain tuning is t0 and the target value reaching time after proportional gain tuning is t1.
t1=t0×Tb/Ta Equation (9)

Equation (10) holds for the integration time Ti1 after integration time tuning.
K1/Ti1×1/2×e0×t1=Mv1 Formula (10)

From equations (9) and (10), Ti1 can be obtained by equation (11).
Ti1=K1×e0/2×Tb/Ta×t0/Mv1 Formula (11)

Therefore, in pattern (a), when Mv0 is less than or equal to Mv1, the proportional gain K1 may be tuned based on equation (8), and the integral time Ti1 may be tuned based on equation (11).

Next, the case of pattern (c) shown in FIG. 4(b) and the case of pattern (d) shown in FIG. 4(c) will be described. The details will be described later, but to state the conclusion first, in both cases of pattern (c) and pattern (d), tuning is performed to increase the proportional gain, and further tuning is performed to lengthen the integration time.

In pattern (c), the overshoot amount is equal to or less than the upper limit value Ov_lim, but the arrival time is longer than the target time t_lim. Therefore, it can be said that the responsiveness is poor, so tuning is required to reduce the arrival time to t_lim or less.

In pattern (d), the arrival time is longer than the target time t_lim, and the overshoot amount is greater than the upper limit value Ov_lim. Therefore, it can be said that stability is lacking and responsiveness is poor, so tuning is required to keep the arrival time below t_lim and the amount of overshoot below Ov_lim.

First, consider tuning to reduce the arrival time to t_lim or less. The reason why the arrival time is longer than t_lim is that the proportional action is weak. Therefore, it is necessary to perform tuning to increase the proportional gain. However, if the proportional gain is increased, the integral action also increases, so it is preferable to tune the integral time after tuning the proportional gain.

A specific example of proportional gain tuning will be described with reference to FIG. Assume that the proportional gain before tuning is K0, the proportional gain after tuning is K1, the initial deviation is e0, and the arrival time before tuning is t0. Consider tuning such that the arrival time after tuning is equal to t_lim. Focus on the change speed a and the change speed b before and after tuning. The rate of change a and the rate of change b are given by equations (12) and (13), respectively.
a=e0/t0 Formula (12)
b=e0/t_lim Equation (13)

Regarding the relationship between the rate of change and the proportional gain, since the above equation (8) holds, the proportional gain K1 after tuning can be obtained from the equation (14).
K1=t0/t_lim Equation (14)

Next, consider tuning the integration time. In this tuning, for example, by tuning the manipulated variable when the target value is reached to be equal to the manipulated variable Mv0 when the target value is reached, as in the case of pattern (a), the amount of overshoot can be reduced even in the case of pattern (d). It can be less than or equal to Ov_lim. Therefore, similar tuning can be performed for both pattern (c) and pattern (d).

As for a specific example, the same way of thinking as in the case where Mv0 is greater than Mv1 in pattern (b) can be adopted. Let Ti0 be the integration time before tuning, and Ti0 be the integration time after tuning. Similar to Equation (3) above, Equation (15) holds. Then, Ti1 can be obtained by Equation (16), which is a modified Equation (15).
K1/Ti1×1/2×e0×t_lim=Mv1 Formula (15)
Ti1=K1×e0/2×t_lim/Mv1 Formula (16)

Therefore, in pattern (c) and pattern (d), for example, the proportional gain may be tuned based on equation (14), and the integration time may be tuned based on equation (16).

So far, the tuning based on the change in the control amount at the time of starting operation has been explained. Next, referring to FIG. 8, tuning based on changes in the controlled variable during stable operation will be described. Tuning based on changes in the control amount during stable operation is performed to suppress hunting that occurs during stable operation. If the amount of hunting is too large, it can be said that the change in the blowing temperature is large, which impairs the comfort of the people in the room. Therefore, it can be said that the hunting amount is preferably equal to or less than the hunting upper limit value Ha_lim.

FIG. 8 shows that the hunting amount Ha exceeds the upper limit Ha_lim. In this case, tuning is required to keep the hunting amount Ha below Ha_lim.

As a specific example, an example of tuning for setting the hunting amount after tuning to Ha_lim will be given. Let Hf be the time from when the target value is reached until the change in the controlled variable reaches Ha. Also, let Hf1 be the time from when the target value is reached until the change in the control amount reaches Ha_lim after tuning.

In the case before tuning, the proportional action and integral action from the time when the target value is reached until the change in the control amount reaches Ha are represented by equations (17) and (18).
Proportional action = K0 x Ha Equation (17)
Integral action = K0/Ti0×Ha×Hf/2 Formula (18)

Comparing the size of the proportional action and the integral action, tuning should be performed to reduce the larger one. From equations (17) and (18), it is possible to compare the magnitudes of proportional action and integral action by comparing the magnitudes of Hf and 2Ti0. If Hf<2Ti0, the proportional action is larger, and if Hf>2Ti0, the integral action is larger.

First, consider the case where the proportional action is greater than the integral action, ie Hf<2Ti0. In this case, tuning is first performed to reduce the proportional gain. Then, after that, it is preferable to tune the integration time as well.

I will give a specific example. Pay attention to the change speed c and the change speed d before and after tuning. The rate of change referred to here is the average rate of change from when the target value is reached until the control amount changes to Ha or Ha_lim. The rate of change c and the rate of change d are represented by equations (19) and (20), respectively.
c=Ha/Hf Formula (19)
d=Ha_lim/Hf1 Formula (20)

Then, as in the case shown in FIG. 6, consider equalizing the length of the line segment corresponding to the change speed c and the length of the line segment corresponding to the change speed d. Then, since equation (21) holds, Hf1 can be obtained from equation (21). Then, d can also be obtained from equation (20).
Hf2+ ^Ha2 =Hf12 ^{+ Ha_lim 2 formula} (21)

Then, the proportional gain K1 after tuning can be obtained by equation (22).
K1=K0×d/c Formula (22)

Then, in order to restore the integral action changed by the tuning of the proportional gain, the integral time is tuned based on the equation (23).
Ti1=K1/K0×Ti0 formula (23)

Therefore, when the proportional action is greater than the integral action, for example, the proportional gain may be tuned based on equation (22), and the integral time may be tuned based on equation (23).

Next, consider the case where the integral action is greater than the proportional action, ie Hf>2Ti0. In this case, tuning is performed to lengthen the integration time.

I will give a specific example. As in the above case, attention is focused on the change speed c and the change speed d before and after tuning. In this case, c and d should be multiplied by d/c, so equation (24) holds. Therefore, the post-tuning integration time Ti1 can be obtained from equation (25).
K0/Ti1=K0/Ti0×d/c Formula (24)
Ti1=c/d×Ti0 Formula (25)

Therefore, when the integral action is larger than the proportional action, the integral time can be tuned based on Equation (25), for example.

The tuning based on the change in the control amount during stable operation has been described above. Next, referring to FIGS. 9, 10 and 11, the tuning operation of the startup operation by the air conditioning control device 10 will be described. It should be noted that the timing for tuning the start-up operation can be arbitrarily selected as long as the information necessary for tuning is available. For example, it may be performed during start-up operation, during stable operation, or at the end of operation. For example, when tuning is performed during start-up operation, tuning may be performed based on information obtained during the previous start-up operation.

First, referring to FIG. 9, the overall operation flow of tuning will be described. The tuning unit 120 of the air conditioning control device 10 acquires the history of controlled variables stored in the storage unit 110 in time series (step S101). It should be noted that the history of the amount of control referred to here is the history of the amount of control during the start-up operation. For example, this corresponds to the history of the controlled variable from the time of startup until the change in the controlled variable stabilizes.

The target value acquisition unit 121 of the tuning unit 120 acquires the target value stored in the storage unit 110 (step S102). The overshoot amount acquisition unit 122 acquires the overshoot amount based on the history and target value of the control amount (step S103). The arrival time acquisition unit 123 acquires the arrival time based on the history of the controlled variable and the target value (step S104).

The tuning unit 120 acquires the history of the manipulated variable from the storage unit 110, and based on the history of the manipulated variable, the history of the controlled variable, and the target value, determines the manipulated variable when reaching the target value and the manipulated variable when stable. (step S105). The tuning unit 120 acquires the target time from the storage unit 110 and determines whether or not the arrival time is equal to or less than the target time (step S106).

If the arrival time is longer than the target time (step S106: No), the above pattern (c) or pattern (d) applies, so the tuning unit 120 performs tuning for pattern (c) and pattern (d). (Step S107), the tuning operation is terminated.

If the arrival time is equal to or less than the target time (step S106: Yes), the tuning unit 120 acquires the overshoot upper limit value stored in the storage unit 110, and determines whether or not the overshoot amount is equal to or less than the upper limit value. (step S108).

If the overshoot amount is greater than the upper limit value (step S108: No), the above pattern (a) applies, so the tuning unit 120 performs tuning for pattern (a) (step S109), and performs the tuning operation. finish. If the overshoot amount is equal to or less than the upper limit value (step S108: Yes), the pattern (a) described above, that is, the case where tuning is unnecessary, is applied, so the operation ends without tuning.

Referring to FIG. 10, the operation of tuning in the case of pattern (a) in step S109 of FIG. 9 will be described.

The tuning unit 120 determines whether or not the manipulated variable Mv0 at the time of reaching the target value is equal to or less than the manipulated variable Mv1 at the time of stability (step S901).

If Mv0 is greater than Mv1 (step S901: No), the tuning unit 120 performs tuning to lengthen the integration time (step S902), and ends the tuning operation. Tuning of the integration time is performed, for example, based on the above equation (4).

If Mv0 is less than or equal to Mv1 (step S901: Yes), the tuning unit 120 first performs tuning to reduce the proportional gain (step S903). Tuning of the proportional gain is performed, for example, based on the above equation (8). Subsequently, the tuning unit 120 performs tuning to shorten the integration time (step S904), and ends the tuning operation. Tuning of the integration time is performed, for example, based on the above equation (11).

Referring to FIG. 11, the tuning operation for pattern (c) and pattern (d) in step S107 of FIG. 9 will be described.

The tuning unit 120 first performs tuning to increase the proportional gain (step S701). Tuning of the proportional gain is performed, for example, based on the above equation (14). Subsequently, the tuning unit 120 performs tuning to lengthen the integration time (step S702), and ends the tuning operation. Tuning of the integration time is performed, for example, based on the above equation (16).

The tuning of the start-up operation has been described above. Next, the operation of tuning for stable operation will be described with reference to FIG. The timing of tuning for stable operation can also be arbitrarily selected as long as the information necessary for tuning is available. However, since the control parameters stored in the storage unit 110 are updated when the start-up tuning is performed, the operation is continued until the stable operation is achieved after the start-up operation tuning, and the information acquired after the stable operation is obtained. It is preferable to tune based on

The tuning unit 120 of the air conditioning control device 10 acquires the control amount history and the target value stored in the storage unit 110, and the hunting amount acquisition unit 124 of the tuning unit 120 acquires the control amount history and the target value based on the control amount history and target value. A hunting amount is obtained (step S201). It should be noted that the history of the controlled variable referred to here is the history of the controlled variable during stable operation. For example, it corresponds to the history of the controlled variable from when the change in the controlled variable is stabilized to when a certain period of time has elapsed.

The tuning unit 120 acquires the upper limit value of hunting stored in the storage unit 110, and determines whether or not the amount of hunting is greater than the upper limit value (step S202). If the hunting amount is equal to or less than the upper limit value (step S202: No), the tuning operation is terminated because tuning is unnecessary.

If the hunting amount is greater than the upper limit value (step S202: Yes), the tuning unit 120 sets the time Hf from when the controlled variable reaches the target value to when the deviation between the controlled variable and the target value becomes equal to the hunting amount as a threshold value. It is determined whether or not (step S203). As this threshold value, for example, 2Ti0 is adopted based on the above equations (17) and (18). Note that Ti0 is the integration time before tuning.

If Hf is longer than the threshold (step S203: No), the tuning unit 120 performs tuning to lengthen the integration time (step S204), and ends the tuning operation. Tuning of the integration time is performed, for example, based on the above equation (25).

If Hf is equal to or less than the threshold (step S203: Yes), the tuning unit 120 first performs tuning to decrease the proportional gain (step S205). Tuning of the proportional gain is performed, for example, based on the above equation (22). Subsequently, the tuning unit 120 performs tuning to shorten the integration time (step S206), and ends the tuning operation. Tuning of the integration time is performed, for example, based on the above equation (23).

The air conditioning system 1 according to the embodiment has been described above. According to the air conditioning system 1, control parameters can be tuned without performing special operation. Therefore, for example, tuning can be performed without impairing the comfort of a person in the room to be air-conditioned.

Further, according to the air conditioning system 1, tuning is performed based on information obtained during actual operation, so tuning can be easily performed without separately preparing a simulator.

Further, according to the air conditioning system 1, since tuning is performed in consideration of both the startup operation and the stable operation, control parameters can be tuned with high accuracy.

(Modification)
In the above-described embodiment, the air conditioning control device 10 performs PID control with the air conditioner 6 as the control target. However, the controlled object is not limited to air conditioners. For example, the present invention can also be applied to a control device that controls an elevator. In this case, for example, it is conceivable to control the number of revolutions of a motor mounted on an elevator as an operation amount and the position of the elevator as a control amount.

In the above-described embodiments, no tuning is performed on the derivative time. Therefore, the above-described embodiment can also be applied to the case where the derivative time is 0, that is, to the case of PI (Proportional-Integral) control. Accordingly, proportional-integral-derivative control in the present invention naturally includes proportional-integral control.

The tuning in the above embodiment is merely an example, and the tuning in the present invention is not limited to these. For example, tuning may be performed in consideration of derivative time. Moreover, it is not always necessary to perform tuning in all the cases described in the embodiments. For example, it is also possible to employ a form in which only tuning for lengthening the integration time is performed, and the arrival time is not considered.

1 air conditioning system, 2 heat source device, 3 primary pump, 4 secondary pump, 5 water pipe, 6 air conditioner, 10 air conditioning control device, 61 cold/hot water coil, 62 valve, 63 blower, 64 temperature sensor, 100 control amount acquisition unit , 110 storage unit, 120 tuning unit, 121 target value acquisition unit, 122 overshoot amount acquisition unit, 123 arrival time acquisition unit, 124 hunting amount acquisition unit, 130 valve control unit, 1000 bus, 1001 processor, 1002 memory, 1003 interface , 1004 secondary storage.

Claims (10)

A control device for controlling a controlled object by proportional-integral-derivative control using a proportional gain, an integral time, and a derivative time as control parameters ,
a controlled variable acquiring means for acquiring a controlled variable of the controlled object;
target value acquisition means for acquiring a target value of the controlled variable;
an overshoot amount acquiring means for acquiring an overshoot amount of the control amount during start-up operation of the controlled object;
an arrival time acquiring means for acquiring an arrival time from when the controlled object is activated until the controlled variable reaches the target value;
Hunting amount acquisition means for acquiring a hunting amount of the control amount during stable operation of the controlled object;
At least one of: the amount of overshoot is greater than a predetermined upper limit of overshoot; the arrival time is longer than a predetermined target time; and the amount of hunting is greater than a predetermined upper limit of hunting. a tuning means for tuning the control parameters when satisfying
control means for determining a manipulated variable based on the controlled variable, the target value, and the control parameter, and controlling the controlled object based on the manipulated variable;
with
The tuning means adjusts the hunting amount until the hunting amount is greater than the hunting upper limit value and the control amount reaches the target value during the stable operation until the difference between the control amount and the target value becomes equal to the hunting amount. When the time of is less than or equal to the threshold, perform tuning to decrease the proportional gain
Control device. The tuning means is configured such that the overshoot amount is larger than the overshoot upper limit value, the reaching time is equal to or shorter than the target time, and the manipulated variable when the controlled variable reaches the target value is the manipulated variable during stable operation. Tuning to lengthen the integration time when greater than
A control device according to claim 1 . The tuning means is configured such that the overshoot amount is larger than the overshoot upper limit value, the reaching time is equal to or shorter than the target time, and the manipulated variable when the controlled variable reaches the target value is the manipulated variable during stable operation. Tuning to reduce the proportional gain when less than
3. A control device according to claim 1 or 2. The tuning means performs tuning to increase the proportional gain when the arrival time is longer than the target time.
A control device according to any one of claims 1 to 3. The tuning means performs tuning to increase the integral time after performing tuning to increase the proportional gain.
5. A control device according to claim 4. The tuning means performs tuning to decrease the integral time after performing tuning to decrease the proportional gain.
A control device according to claim 1 . The tuning means adjusts the hunting amount until the hunting amount is greater than the hunting upper limit value and the control amount reaches the target value during the stable operation until the difference between the control amount and the target value becomes equal to the hunting amount. is longer than the threshold, perform tuning to lengthen the integration time,
A control device according to any one of claims 1 to 6. An air conditioner and the control device according to any one of claims 1 to 7,
The control device controls the air conditioner,
The controlled variable acquisition means acquires the blown air temperature of the air conditioner as the controlled variable,
The control means controls the air conditioner by controlling an actuator of the air conditioner based on the operation amount.
air conditioning system. A control method for controlling a controlled object by proportional-integral-derivative control using a proportional gain, an integral time, and a derivative time as control parameters ,
a controlled variable obtaining step of obtaining a controlled variable of the controlled object;
a target value obtaining step of obtaining a target value of the controlled variable;
an overshoot amount acquiring step of acquiring an overshoot amount of the control amount during start-up operation of the controlled object;
an arrival time acquisition step of acquiring an arrival time from when the controlled object is activated until the controlled variable reaches the target value;
a hunting amount acquiring step of acquiring a hunting amount of the control amount during stable operation of the controlled object;
At least one of: the amount of overshoot is greater than a predetermined upper limit of overshoot; the arrival time is longer than a predetermined target time; and the amount of hunting is greater than a predetermined upper limit of hunting. a tuning step for tuning the control parameters when satisfying
a control step of controlling the controlled object based on the controlled variable, the target value, and the control parameter;
with
In the tuning step, the hunting amount is greater than the hunting upper limit value, and from when the controlled variable reaches the target value during the stable operation until the difference between the controlled variable and the target value becomes equal to the hunting amount. When the time of is below the threshold, perform tuning to decrease the proportional gain,
control method. A program that causes a computer to control a controlled object by proportional-integral-derivative control using a proportional gain, an integral time, and a derivative time as control parameters ,
to the computer;
a controlled variable obtaining step of obtaining a controlled variable of the controlled object;
a target value obtaining step of obtaining a target value of the controlled variable;
an overshoot amount acquiring step of acquiring an overshoot amount of the control amount during start-up operation of the controlled object;
an arrival time acquisition step of acquiring an arrival time from when the controlled object is activated until the controlled variable reaches the target value;
a hunting amount acquiring step of acquiring a hunting amount of the control amount during stable operation of the controlled object;
At least one of: the amount of overshoot is greater than a predetermined upper limit of overshoot; the arrival time is longer than a predetermined target time; and the amount of hunting is greater than a predetermined upper limit of hunting. a tuning step for tuning the control parameters when satisfying
a control step of controlling the controlled object based on the controlled variable, the target value, and the control parameter;
and
In the tuning step, the hunting amount is greater than the hunting upper limit value, and from when the controlled variable reaches the target value during the stable operation until the difference between the controlled variable and the target value becomes equal to the hunting amount. When the time of is less than or equal to the threshold, perform tuning to decrease the proportional gain
program.

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