JP3972101B2 - Automatic control method and automatic control device - Google Patents

Description

  The present invention relates to an automatic control method and an automatic control device, and more particularly to an automatic control method and an automatic control device that feed back a change amount of a control target.

  PID (Proportional, Integral) is an automatic control method that controls the amount of operation given to the control device that follows the target range value under conditions in which various state variables such as temperature, pressure, flow rate, and level of the control target change over time. , Differentiation) control methods are known. In the conventional PID control, the operation amount of the control object is determined by PID calculation of the deviation between the control amount of the control object and its target value.

  For example, as an improved method using PID control, a set value that can accurately follow the target value of the controlled variable in the automatic control that causes the controlled variable to follow the target value that changes over time Is known (Japanese Patent Laid-Open No. 2001-92501). According to such a control method, there is an advantage that servo control can be performed by accurately following the set value in accordance with the characteristics of the system to be controlled.

Further, while calculating the deviation between the set value becomes the current value and the target detected from the control object, after performing the PID control calculation in accordance with the calculated deviation, the current operation amount of the control target device is given When it is within the predetermined range and the sign of the deviation is reversed, the output ratio preset according to the operation amount within the predetermined range is set to PID. Multiply the control calculation value to output a control operation signal to the control target device, and if it is out of the predetermined range, set the output ratio preset according to the operation amount outside the predetermined range to the PID control calculation value A PID control method is known in which a control operation signal is output to a control target device by multiplying by (Japanese Patent Laid-Open No. 2000-163101).

JP 2001-92501 A

JP 2000-163101 A

  However, in any of the above PID controls, the problem is that when the stability of the system is lost due to disturbance, the state value of the controlled object differs greatly from the target value (such as overshoot) before reaching the target value again. ) In the process.

  For example, when trying to maintain the temperature of a reaction vessel containing a biological enzyme having a certain optimum temperature at the optimum temperature, for example, when a sudden low temperature (disturbance) occurs, a conventional general-purpose PID control method Then, although the temperature of the reaction vessel is finally controlled to the target temperature, in the control process, it passes through a temperature range that greatly deviates from the optimum temperature range of the enzyme in question (Fig. 1). . This leads to a decrease in enzyme reaction, and at the same time, especially when the temperature rises above the optimum temperature, it causes thermal denaturation of the protein that is the main component of the enzyme, and in many cases it is called irreversible inactivation of the enzyme protein. Undesirable results. This is not a problem that occurs only in an enzyme reaction, but a problem that can occur in a temperature control process for a wide range of general life phenomena including cells, tissues, or individuals.

  This problem is also related to the fact that there is a considerable time lag until the target temperature is reached in conventional PID control, and various ideas have been proposed to solve this problem, but it is shorter than the vicinity of the target temperature. When the time is reached, an undesired temperature range due to an overshoot occurs. On the other hand, when the overshoot is reduced, the time to reach the target temperature is delayed. Solution has not been reached.

  Therefore, the present invention provides an automatic control method and an automatic control apparatus that can automatically control a target object to a desired target value more quickly and that can further reduce the over / undershoot width. It is to provide.

  In order to achieve the above object, the inventors have analyzed and extracted a temperature control algorithm possessed by Zasensou, an exceptional thermostatic plant in the plant world, and as a result, have found the automatic control method and the automatic control device of the present invention. It was.

The automatic control method of the present invention is an automatic control method for controlling so that a control amount indicating a physical state of a control target becomes a control amount (target value) in the immediately preceding control cycle.
Using the temperature control algorithm of the control object based on the temperature control mechanism of the thermostatic plant with a heat source, represented by the following formula,
q _{n + 1} = q _n −C _feedback · dT _{n + 1} / dt (1)
T _{n + 1} = C ₁ × Q _{n + 1} (2)
Q _{n + 1} = Q _n + (q ¹ _in + q ² _in ) −q _out (3)
q _out = C ₂ × (T _s −T _a ) (4)
q ¹ _in = C ₃ , q ² _in = C ₄ × H _n (5)
H _{n + 1} = H _n + q _{n + 1} − (q ¹ _in + q ² _in ) (6)
(In the above formula, q _n is the amount of heat that flows in and accumulates from the heat source in the control cycle n, T _n is the temperature of the object to be controlled in the control cycle n, C _feedback is the proportional constant, and Q _n is the above-mentioned in the control cycle n. the amount of heat retained by the controlled object by accumulated heat, q _out is the amount of heat dissipation from the control target, T _s is the surface temperature of the controlled object, T _a is the outside air temperature around the control target, q ¹ _in the heat generation of the control object certain heat content amount, q ² _in the variable heat content of the heating value of the control target, H _n is the amount of heat required for heat generation at the control cycle n of the accumulated heat, the parameter C ₁ is the thermal conductivity of the controlled object Rate, C ₂ is the heat transfer rate of the controlled object, C ₃ is a constant, and C ₄ is the heat rate of the controlled object)
In _order to reproduce the temperature T _n change of the controlled object, the constant C ₃ and the proportional constant C _feedback are determined,
A control operation signal is calculated from a change amount of a control amount indicating a physical state of the control object and the proportional constant C _feedback, and the control object is controlled by the control operation signal.

In addition, the control amount indicating the physical state of the control target is the control amount (target value) in the immediately preceding control cycle using the change amount of the control amount indicating the physical state of the control target and the signal calculated by the proportional constant C _feedback. PID control calculation is performed so that the control object is controlled by the control operation signal of the calculation result .

Further, the automatic control device of the present invention is an automatic control device that performs control so that the control amount indicating the physical state of the control target becomes the control amount (target value) in the immediately preceding control cycle.
First calculation means for calculating a change amount of a control amount indicating a physical state of the control target ;
Second calculation means for calculating a value of the control operation signal by the change amount of the control amount and the proportional constant C _feedback ,
The proportionality constant C _feedback is expressed by the following equation, using a temperature control algorithm of a control object based on a temperature control mechanism of a thermostatic plant having a heat source,
q _{n + 1} = q _n −C _feedback · dT _{n + 1} / dt (1)
T _{n + 1} = C ₁ × Q _{n + 1} (2)
Q _{n + 1} = Q _n + (q ¹ _in + q ² _in ) −q _out (3)
q _out = C ₂ × (T _s −T _a ) (4)
q ¹ _in = C ₃ , q ² _in = C ₄ × H _n (5)
H _{n + 1} = H _n + q _{n + 1} − (q ¹ _in + q ² _in ) (6)
(In the above formula, q _n is the amount of heat that flows in and accumulates from the heat source in the control cycle n, T _n is the temperature of the object to be controlled in the control cycle n, C _feedback is the proportional constant, and Q _n is the above-mentioned in the control cycle n. the amount of heat retained by the controlled object by accumulated heat, q _out is the amount of heat dissipation from the control target, T _s is the surface temperature of the controlled object, T _a is the outside air temperature around the control target, q ¹ _in the heat generation of the control object certain heat content amount, q ² _in the variable heat content of the heating value of the control target, H _n is the amount of heat required for heat generation at the control cycle n of the accumulated heat, the parameter C ₁ is the thermal conductivity of the controlled object Rate, C ₂ is the heat transfer rate of the controlled object, C ₃ is a constant, and C ₄ is the heat rate of the controlled object)
A proportionality constant _{C? Feedback} of the determined to reproduce the temperature T _n change of the control object the constants C ₃ and the proportional constant _{C? Feedback,}
The control target is controlled by the value of the control operation signal calculated by the second calculation means .

In addition, the control amount indicating the physical state of the control target is the control amount (target value) in the immediately preceding control cycle using the change amount of the control amount indicating the physical state of the control target and the signal calculated by the proportional constant C _feedback. PID control calculation means for performing PID control calculation so that the control object is controlled by a value calculated by the PID control calculation means .

  According to the present invention, the control method and apparatus based on the temperature control algorithm of the thermostatic plant Zasensou has the advantageous effect that the target temperature range can be adjusted in a shorter time with the deviation due to disturbance being minimized. Play.

  In addition, it is possible to quickly stabilize the control target in the vicinity of the basic value determined by combining appropriate parameters.

  Further, according to the present invention, there is an advantageous effect that the target temperature can be reached in a shorter time than the conventional PID control method.

  Moreover, according to this invention, there exists an advantageous effect that the temperature of biological objects, such as an enzyme solution and a biological sample, can be kept at the target temperature from the fluctuation | variation by a disturbance on milder conditions. In other words, protein solutions undergo thermal denaturation when exposed to rapid temperature changes in enzyme solutions, etc., but even in such rapid temperature changes, they can be quickly corrected to the vicinity of the target value. It has an advantageous effect of being useful for prevention.

  Further, according to the present invention, the basic value of the control target is determined by the physical constant of the control target, so it is not necessary to determine the basic value of the control target by incorporating a microcomputer or the like, and the physical constant is known. It has the merit that it becomes possible to determine the basic value of the controlled object only by combining the materials.

  In addition, even when it is not clear what kind of substance the control object is made of, it is stable by simply parameterizing the values obtained by measuring various physical constants of the substance and determining the proportional constant accordingly. It has the merit that control becomes possible.

  In the present invention, in the control transfer function that is determined so that the control target becomes a desired target value or target level range, the control calculation is performed using a proportional constant that is calculated so that the change amount per control cycle of the control target becomes zero The controlled object is automatically controlled using the result as a control operation signal.

  In the present invention, the object to be controlled is broad and includes control of a physical state such as temperature, speed, flow rate, pressure, or liquid level, and is not particularly limited. Further, the desired target value refers to a target value when controlling the control target. For example, when it is desired to keep the temperature constant at 25 ° C., the desired target value is 25 ° C.

  In the control transfer function determined so that the control target is a desired target value or target level range, the proportionality constant calculated so that the change amount per control cycle of the control target is zero is the change amount of the control target. It is an important factor from the viewpoint of how much feedback is given to. The parameter constituting the proportionality constant determined from the controlled object is preferably determined from the physical constant of the controlled object. This is from the viewpoint of eliminating the arbitraryness in determining the proportionality constant as much as possible and narrowing down the value more quickly and accurately. Specifically, heat generation rate, thermal conductivity, heat transfer rate, specific heat, thermal diffusion coefficient, thermal resistance, concentration, temperature, humidity, speed, acceleration, frequency. It is determined from at least one selected from the group consisting of mass, density, pressure, water pressure, lift, buoyancy, air resistance, electrical resistance, dielectric constant, and magnetic susceptibility, or a combination selected from these groups preferable.

  In the present invention, a conventional PID control method may be incorporated in order to maintain a constant value with respect to the target value. This eliminates the drawbacks of PID, that is, it repeats over / undershoot until reaching the target value, and it takes time to stabilize the control target, and is almost the same as the target value of the control target. It is also possible to make them coincide, and as a result, there is an advantage that a highly accurate automatic control method can be provided.

  That is, in a preferred embodiment, the amount of change per control cycle of the control target is further calculated with respect to the control operation signal output by the PID control calculation as the deviation between the current value detected from the control target and the target set value. The controlled object can be automatically controlled based on a control operation signal obtained by adding a value derived using a proportionality constant calculated to be zero. Conventional PID control can be applied and is not particularly limited.

An example of PID control will be described with reference to FIG. In PID control, the current value of the object to be controlled is detected at predetermined intervals, the deviation between the detected current value and a preset value set as the target value is calculated, and the calculation is performed. PID control calculation is performed according to the magnitude of the deviation. Then, the operation time corresponding to the total operation amount of the control target device is output to the target device as the PID control calculation result (calculation value). Specifically, in the PID control, the target value tracking system operates by adjusting the three parameters k _I / S, k _P and k _D S in FIG.

  On the other hand, the automatic control method of the present invention obtained on the basis of the control system of Zazenso is a simple circuit in which the control against disturbance is performed by only one parameter C as shown in FIG. 3 (FIG. 3).

  Here, the principle of the automatic control method extracted from the zenith that forms the basis of the present invention will be described as follows.

  First, FIG. 4 shows a model diagram of a control algorithm extracted from Zazenso. It is characterized in that the water movement of the system composed of two tanks is directly related to temperature control. The two faucets of the second tank control the heat generation of the system, and the movement of water from the first tank to the second tank is responsible for feedback control of temperature fluctuations (Fig. 4). Here, as the amount of feedback, conventionally, the difference between the set temperature and the current temperature, that is, the deviation was used in the PID control. It has the unique feature of being fed back. Such a control method of the present invention is a system that can make temperature fluctuation due to disturbance zero in a shorter time.

  FIG. 5 shows a block diagram of an automatic control method in which PID control is incorporated in the control algorithm. That is, in the automatic control method of the present invention in which PID control is incorporated, the deviation between the target value and the current value is calculated by PID control, and the result is fed back through the Zaseng algorithm.

Next, the automatic control device of the present invention will be described.
The automatic control device of the present invention includes a first calculation unit that calculates a change amount per control cycle of a control target, and a proportionality that is calculated so that the change amount per control cycle calculated by the first calculation unit becomes zero. It has a 2nd calculation means which calculates the value calculated by control by the constant, and a control means which feeds back the value calculated by said 2nd calculation means to a controlled object, It is characterized by the above-mentioned.

  The first calculation means calculates an amount of change appropriate for the control target. The first calculation unit is not particularly limited as long as the change amount of the control target can be grasped. The change amount of the control target calculated by the first calculation means can be recorded in a predetermined recorder. The recorded change amount is provided to the next second calculating means.

  The second calculating means multiplies the amount of change calculated by the first calculating means by a proportionality constant determined from the control object and a desired target value, that is, a control cycle calculated by the first calculating means. A value controlled by a proportional constant calculated so that the amount of change per hit becomes zero is calculated. The feedback value calculated by the second calculation means can also be recorded in a predetermined recorder. The recorded feedback value is provided to the next control means to perform the automatic control of the present invention.

  Here, the control target is broad and includes control of a physical state such as temperature, speed, flow rate, pressure, or liquid level, and is not particularly limited. Further, the desired target value refers to a target value when controlling the control target. For example, when it is desired to keep the temperature constant at 25 ° C., the desired target value is 25 ° C.

  In the control transfer function determined so that the control target is a desired target value or target level range, the proportionality constant calculated so that the change amount per control cycle of the control target is zero is the change amount of the control target. It is an important factor from the viewpoint of how much feedback is given to. The parameter constituting the proportionality constant determined from the controlled object is preferably determined from the physical constant of the controlled object. This is from the viewpoint of eliminating the arbitraryness in determining the proportionality constant as much as possible and narrowing down the value more quickly and accurately. Specifically, heat generation rate, thermal conductivity, heat transfer rate, specific heat, thermal diffusion coefficient, thermal resistance, concentration, temperature, humidity, speed, acceleration, frequency. It is determined from at least one selected from the group consisting of mass, density, pressure, water pressure, lift, buoyancy, air resistance, electrical resistance, dielectric constant, and magnetic susceptibility, or a combination selected from these groups preferable.

  The control means feeds back the feedback value calculated by the second calculation means to the control target. The control unit controls the feedback value to the control target based on the information calculated by the second calculation unit.

  The control means is constituted by a CPU, for example, and executes feedback control based on a program stored in a memory such as a flash memory or a DRAM, or a recording medium such as an optical disk or a floppy (registered trademark) disk. This quickly stabilizes the controlled object.

  In a preferred embodiment of the present invention, the change between the current value detected from the control target and the target set value is a change per control cycle of the control target with respect to the control operation signal output by the PID control calculation. Control means for automatically controlling the controlled object is provided based on a control operation signal obtained by adding a value derived using a proportionality constant calculated so that the amount becomes zero. The control means is for establishing a control system in which PID control is incorporated with respect to the automatic control extracted from the sensation, thereby quickly stabilizing the control target and achieving a predetermined target value. It is possible to provide an automatic control device that can be approached as much as possible.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not intended to be interpreted as being limited to the following examples.

Example 1
First, the zenith type automatic control method according to the present invention and the conventional PID automatic control method were compared. In the zenith type automatic control, thermal conductivity C ₁ , heat transfer coefficient C ₂ , and heat generation rate C ₄ were used as physical constants for determining the proportionality constant. Specifically, a parameter called heat generation rate C ₄ is used as the energy conversion efficiency, the value is calculated from 0.2 and an actual measurement value , and the thermal conductivity C ₁ , which is a parameter for transmitting the obtained heat to the entire control target, is 0.33. a determined, calculated heat transfer coefficient C ₂ to 0.2 is a parameter related to the heat radiation when the heat is taken away from the control target, by the proportionality constant _{C? feedback} relating to the feedback at that time and 1.0, automatic Temperature control is realized.

As the control transfer function at this time, the equation of the damped oscillation, which is one of the second-order lag transfer functions, was adopted from the actual temperature data waveform of Zazenso. This man equation is, because it is second-order differential equation, it can be decomposed into two first-order differential equations. In other words, it is possible to model by quantitative change of two things. Here, it was performed modeled using thermal change in the amount of two heat storage tank (Figure 4). In this model, is fed back to the heat quantity change in temperature of the skunk cabbage spadix moves from first heat source of the heat storage tank, the decrease is determined. When the heat amount to be transferred from first storage tank is determined, it has two heat amount of the heat storage tank of the eye increases and decreases flow, accordingly, the amount of heat transferred from the second heat storage tank changes To do. This increases or decreases the amount of heat generated in the zenitha spike, and determines the temperature of the zenzhi spike. This model is represented by mathematical formulas as shown in FIG. The parameters thermal conductivity C ₁ , heat transfer coefficient C ₂ , and heat generation rate C ₄ appearing here are uniquely determined from experimental measurements and the like. To reproduce the temperature change of the skunk cabbage determines the arbitrary value C ₃ trial and error, when all parameters are determined, accordingly proportional constant _{C? Feedback} is determined. Here, C ₃ was obtained as 2.0, and proportionality constant C _feedback was obtained as 1.0.

FIG. 7 shows a simulation result on a computer for the Zazen type automatic control method of the present invention and the conventional PID automatic control method when the temperature is rapidly lowered. FIG. 8 shows a simulation result on a computer for the Zazen type automatic control method of the present invention and the conventional PID automatic control method when the temperature is rapidly increased.

  From these results, the temperature controlled by the temperature control algorithm extracted from the genus persica can keep the width of over / undershoot much smaller than the temperature control by PID control against the sudden change of the air temperature. Turned out to be obvious.

Example 2
Next, the difference in over / undershoot amount was examined using the automatic control method and apparatus of the present invention.

FIG. 9 shows the range of over / undershoot with respect to various disturbance (temperature) changes. As a result, it can be seen that the temperature control algorithm extracted from the sensation always has a smaller over / undershoot width than the PID control. Furthermore, the width of the overshoot is much smaller than that of PID control, which means that even if there is a sudden rise in temperature by using the temperature control algorithm extracted from Zazensou, the temperature of the object is kept within a certain temperature range. Was found to be possible to maintain.

Example 3
Next, the temperature fluctuation when the PID control system was incorporated in the automatic control method and the automatic control apparatus of the present invention was examined. Conditions such as the proportionality constant are as described in Example 1.

FIG. 10 shows the results of simulation on a computer for the automatic control method of the Zazen type + PID control of the present invention and the conventional automatic PID control method when the temperature is drastically lowered. FIG. 11 shows the results of simulation on a computer for the automatic control method of the Zazen type + PID of the present invention and the conventional automatic PID control method when the temperature is rapidly increased.

As is apparent from the results of FIGS. 10 and 11 , it has been found that the automatic control method and apparatus of the present invention can further reduce the width of the over / undershoot, which is a major disadvantage of PID. This indicates that the accuracy of PID control can be improved by using the temperature control algorithm extracted from the sensation as a filter.

FIG. 1 shows the temperature response corresponding to a rapid change in the temperature when the optimum temperature of the enzyme reaction is controlled by PID control and the optimum temperature zone of the enzyme reaction. FIG. 2 shows a block diagram of PID control. FIG. 3 shows a block diagram of a control algorithm extracted from Zazenso. FIG. 4 shows a model diagram of the control algorithm extracted from Zazenso. FIG. 5 shows a block diagram of PID control improved by a control algorithm extracted from Zazenso. FIG. 6 shows an example of a mathematical expression used when a control algorithm model extracted from Zazenso is simulated on a computer. FIG. 7 shows the PID control and the algorithm sound response extracted from the sensation when the temperature drops sharply. FIG. 8 shows the temperature response of the control algorithm extracted from the PID control and the sensation when the temperature suddenly rises. FIG. 9 shows the width of the over / undershoot of the control algorithm extracted from the PID control and the sensation for various disturbance (temperature) changes. FIG. 10 shows the temperature response of the PID control improved by the control algorithm extracted from the PID control and the sensation when the air temperature drops rapidly. FIG. 11 shows the temperature response of the PID control improved by the control algorithm extracted from the PID control and the sensation when the temperature rapidly rises.

Claims (4)

In the automatic control method for controlling the control amount indicating the physical state of the control target to be the control amount (target value) in the immediately preceding control cycle,
Using the temperature control algorithm of the control object based on the temperature control mechanism of the thermostatic plant with a heat source, represented by the following formula,
q _{n + 1} = q _n −C _feedback · dT _{n + 1} / dt (1)
T _{n + 1} = C ₁ × Q _{n + 1} (2)
Q _{n + 1} = Q _n + (q ¹ _in + q ² _in ) −q _out (3)
q _out = C ₂ × (T _s −T _a ) (4)
q ¹ _in = C ₃ , q ² _in = C ₄ × H _n (5)
H _{n + 1} = H _n + q _{n + 1} − (q ¹ _in + q ² _in ) (6)
(In the above formula, q _n is the amount of heat that flows in and accumulates from the heat source in the control cycle n, T _n is the temperature of the object to be controlled in the control cycle n, C _feedback is the proportional constant, and Q _n is the above-mentioned in the control cycle n. the amount of heat retained by the controlled object by accumulated heat, q _out is the amount of heat dissipation from the control target, T _s is the surface temperature of the controlled object, T _a is the outside air temperature around the control target, q ¹ _in the heat generation of the control object certain heat content amount, q ² _in the variable heat content of the heating value of the control target, H _n is the amount of heat required for heat generation at the control cycle n of the accumulated heat, the parameter C ₁ is the thermal conductivity of the controlled object Rate, C ₂ is the heat transfer rate of the controlled object, C ₃ is a constant, and C ₄ is the heat rate of the controlled object)
In _order to reproduce the temperature T _n change of the controlled object, the constant C ₃ and the proportional constant C _feedback are determined,
Automatic control method the amount of change controlled variable indicating the physical condition of the control object and calculates the control operation signal by the proportional constant _{C? Feedback,} controls the controlled object by the control operation signal. The amount of change in the control amount indicating the physical state of the control target and the proportionality constant C _feedback Is used to calculate the PID control so that the control amount indicating the physical state of the control target becomes the control amount (target value) in the immediately preceding control cycle, and the control target is determined by the control operation signal of the calculation result. The automatic control method according to claim 1 to control. In an automatic control device that performs control so that a control amount indicating a physical state of a control target becomes a control amount (target value) in the immediately preceding control cycle,
First calculation means for calculating a change amount of a control amount indicating a physical state of the control target ;
Second calculation means for calculating a value of the control operation signal by the change amount of the control amount and the proportional constant C _feedback ,
The proportionality constant C _feedback is expressed by the following equation, using a temperature control algorithm of a control object based on a temperature control mechanism of a thermostatic plant having a heat source,
q _{n + 1} = q _n −C _feedback · dT _{n + 1} / dt (1)
T _{n + 1} = C ₁ × Q _{n + 1} (2)
Q _{n + 1} = Q _n + (q ¹ _in + q ² _in ) −q _out (3)
q _out = C ₂ × (T _s −T _a ) (4)
q ¹ _in = C ₃ , q ² _in = C ₄ × H _n (5)
H _{n + 1} = H _n + q _{n + 1} − (q ¹ _in + q ² _in ) (6)
(In the above formula, q _n is the amount of heat that flows in and accumulates from the heat source in the control cycle n, T _n is the temperature of the object to be controlled in the control cycle n, C _feedback is the proportional constant, and Q _n is the above-mentioned in the control cycle n. the amount of heat retained by the controlled object by accumulated heat, q _out is the amount of heat dissipation from the control target, T _s is the surface temperature of the controlled object, T _a is the outside air temperature around the control target, q ¹ _in the heat generation of the control object certain heat content amount, q ² _in the variable heat content of the heating value of the control target, H _n is the amount of heat required for heat generation at the control cycle n of the accumulated heat, the parameter C ₁ is the thermal conductivity of the controlled object Rate, C ₂ is the heat transfer rate of the controlled object, C ₃ is a constant, and C ₄ is the heat rate of the controlled object)
A proportionality constant _{C? Feedback} of the determined to reproduce the temperature T _n change of the control object the constants C ₃ and the proportional constant _{C? Feedback,}
An automatic control device that controls the control object based on a value of the control operation signal calculated by the second calculation means . The amount of change in the control amount indicating the physical state of the control target and the proportionality constant C _feedback And a PID control calculation means for performing PID control calculation so that the control amount indicating the physical state of the control target becomes the control amount (target value) in the immediately preceding control cycle, using the signal calculated by The automatic control apparatus according to claim 3, wherein the control object is controlled by a value calculated by the above.