JP5280183B2 - Control apparatus and control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quickly and reliably switch a hybrid heat-treatment furnace of a gas combustion furnace and an electric furnace from a gas mode to an electric mode. <P>SOLUTION: A control device includes: a first phase switch part 3 for setting a tracking phase, a second phase switch part 4 for setting a convergence phase, a third phase switch part 5 for setting a stabilization phase, a first manipulated variable decision part 6 for outputting a manipulated variable in the tracking phase, a second manipulated variable decision part 7 for outputting a manipulated variable in the convergence phase, a third manipulated variable decision part 8 for outputting a manipulated variable in the stabilization phase, a gas-mode manipulated variable output part 9 for outputting the manipulated variable from the first manipulated variable decision part 6 to an operation means for actuating a hybrid heat-treatment furnace as a gas combustion furnace, and an electric-mode manipulated variable output part 10 for outputting the manipulated variables from the second and third manipulated variable decision parts 7 and 8 to an operation means for actuating the hybrid heat-treatment furnace as an electric furnace. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a control device and a control method for performing set value tracking control by giving an operation amount to a control target so that the control amount follows a set value, for example, a hybrid heat treatment furnace of a gas combustion furnace and an electric furnace. The present invention relates to a control device and a control method for performing temperature rise control.

  In order to meet the requirements of both energy saving control and high precision control as much as possible, a hybrid heat treatment furnace of gas combustion furnace and electric furnace has been developed. FIG. 6 is a diagram showing an example of a temperature control system in a hybrid heat treatment furnace. In the example of FIG. 6, an electric heater 101, a gas heater 102, and a temperature sensor 103 are installed inside the heat treatment furnace 100. The temperature sensor 103 measures the temperature PV of air heated by the electric heater 101 or the gas heater 102. The temperature controller 104 calculates the manipulated variable MV so that the temperature PV matches the control amount set value SP. The power regulator 105 supplies power corresponding to the operation amount MV to the electric heater 101. The gas flow regulator 106 supplies a gas having a flow rate corresponding to the operation amount MV to the gas heater 102. Thus, the temperature controller 104 controls the temperature in the heat treatment furnace 100.

  In the hybrid heat treatment furnace as shown in FIG. 6, when the temperature of the heat treatment furnace 100 is increased from a low temperature to a high temperature, the gas flow regulator 106 and the gas heater 102 are used to operate as a gas combustion furnace advantageous in terms of energy. To do. On the other hand, when maintaining the temperature of the heat treatment furnace 100 at a constant value with high accuracy after the temperature rise, the power regulator 105 and the electric heater 101 are used, but the energy efficiency is inferior to that of the gas combustion furnace. It operates as an advantageous electric furnace with high responsiveness.

  In the heating function as the gas combustion furnace and the heating function as the electric furnace, the heating effect actually appears from the time when the operation amount MV which is a control command is output from the temperature controller 104 in order to execute the temperature control. The time until and the magnitude of the effect after the effect appears are different. That is, the characteristics of the controlled object are different when operating as a gas combustion furnace (gas mode) and when operating as an electric furnace (electric mode). When the characteristics of the controlled object are different as described above, for example, the PID parameter in the PID control needs to be switched to a value suitable for each in the gas mode and the electric mode. In the control switching method in which the gas treatment mode is set to raise the temperature of the heat treatment furnace 100 and the electric mode is set to maintain the heat treatment furnace 100 at a constant temperature, the electric mode is a normal operation state as the heat treatment furnace. Therefore, in order to shift to the operating state early, it is preferable to obtain a stable state in the electric mode early. In this case, the following problems occur.

(A) For example, if the method of switching to the electric mode when the temperature of the heat treatment furnace reaches the set value SP in the gas mode is adopted as a method of switching the control early, a temperature disturbance peculiar to discontinuous control occurs. To do. Until this disturbance is settled, the operation state as a heat treatment furnace cannot be entered, so that time and energy are lost.
(B) For example, if the method of switching to the electric mode at the time when the temperature of the heat treatment furnace is set to the set value SP in the gas mode is adopted as a method of switching the control reliably, it takes time in the gas mode that is difficult to control with high accuracy. To settle the temperature. In this method, the time and energy until settling in the gas mode is substantially lost.

  As a technique for obtaining a good control characteristic when the control is switched, there is a control device disclosed in Patent Document 1. When the control amount PV is switched, the control device disclosed in Patent Document 1 resets the past control deviation and the change amount of the past control deviation to zero, sets the set value SP to the control amount PV_cur at the time of switching, and controls simultaneously. By making the manipulated variable MV_cur at the time when the amount PV switches to the previous value, it is substantially equivalent to the situation where SP = PV_cur, PV = PV_cur, and MV = MV_cur were set before the controlled variable PV was switched. In order to approach the state where the original control target is achieved step by step from this state, the first-order lag filtering process is applied to the set value SP to obtain the set value SP from SP = PV_cur. It will gradually approach the target value.

JP 2007-34574 A

As described above, in the hybrid heat treatment furnace of the gas combustion furnace and the electric furnace, the problems (A) and (B) described above occur when switching from the gas mode to the electric mode.
In addition, the technique disclosed in Patent Document 1 is to switch the target temperature to be controlled so that good characteristics can be obtained at the time of switching. However, in the switching from the gas mode to the electric mode in the hybrid heat treatment furnace, the control amount PV at the time of switching coincides with the original set value SP from the beginning, so the technique disclosed in Patent Document 1 is the above problem. Obviously, it is not an effective solution for the point.
The above-described problems are not limited to the hybrid heat treatment furnace, and similarly occur if the control target has two operation modes.

  The present invention has been made in order to solve the above-described problem. First, a control object having two operation modes, ie, a first mode excellent in energy efficiency and a second mode excellent in control responsiveness, is provided. An object of the present invention is to provide a control device and a control method capable of quickly and surely switching from the first mode to the second mode when operating in the second mode after operating in the first mode.

The control device according to the present invention includes a first phase switching unit that switches to the follow-up phase with a set value change start time as a start time of the follow-up phase, and a specific setting in which the control amount does not exceed the set value in the follow-up phase. Second phase switching means for switching to the convergence phase with the value follow-up control elapsed time as the start time of the convergence phase; and the stable phase with the time point when reaching a preset condition in the convergence phase as the start time of the stable phase A third phase switching means for switching to a phase, a first operation amount determining means for continuously outputting an operation amount for causing the control amount to follow a set value in the follow-up phase, and a control amount in the convergence phase. A second manipulated variable determining means for continuously outputting an manipulated variable that converges in the vicinity of the set value; The outputs an operation amount to stabilize the amount to the set value continuously third manipulated variable determining means and a second which is excellent in the first mode and the responsiveness of control than the first mode with excellent energy efficiency The first operation means for operating the control object having two operation modes of the first mode in the first mode outputs the operation amount output from the first operation amount determination means in the follow-up phase. From the second manipulated variable determining means or the third manipulated variable determining means in the convergence phase and the stable phase. And a second operation amount output means for outputting the output operation amount.
In one configuration example of the control device of the present invention, the control target is a hybrid heat treatment furnace of a gas combustion furnace and an electric furnace, and the first mode is a gas mode that operates as a gas combustion furnace, The second mode is an electric mode operating as an electric furnace.
Further, in one configuration example of the control device according to the present invention, the second phase switching unit calculates a predicted value of a remaining arrival time, which is a time until the set value is reached from the current control amount in the follow-up phase, as a set value. Is calculated based on the deviation between the control amount and the rate of change of the control amount, and the time when the calculated predicted arrival remaining time value becomes smaller than a preset time index is set as the start time of the convergence phase. It is what.

Further, the control method of the present invention includes a first phase switching procedure for switching to the following phase with a set value change start time as a start time of the follow-up phase, and an operation for causing the control amount to follow the set value in the follow-up phase. The operation amount determination procedure in the follow-up phase for continuously outputting the amount, the first mode excellent in energy efficiency, and the second operation mode superior in control response than the first mode. An operation amount output procedure in the follow-up phase for outputting the operation amount determined in the operation amount determination procedure in the follow-up phase to the first operation means for operating the control target in the first mode; and control in the follow-up phase A second phase switching procedure for switching to the convergence phase with a specified setpoint follow-up control elapsed time at which the amount does not exceed the set value as a convergence phase start time In the convergence phase, the operation amount determination procedure in the convergence phase for continuously outputting the operation amount for converging the control amount in the vicinity of the set value, and the second operation means for operating the control target in the second mode, An operation amount output procedure in the convergence phase for outputting the operation amount determined in the operation amount determination procedure in the convergence phase, and a time point when reaching a preset condition in the convergence phase is set as the start point of the stable phase to the stable phase. A third phase switching procedure for performing switching, a stable phase manipulated variable determining procedure for continuously outputting an manipulated variable that stabilizes the controlled variable to a set value in the stable phase, and the second operating means, A stable phase manipulated variable output procedure for outputting the manipulated variable determined by the stable phase manipulated variable determining procedure.

  According to the present invention, a control target having two operation modes of a first mode with excellent energy efficiency and a second mode with excellent control response is first operated after being operated in the first mode. When operating in the second mode, it is possible to quickly and surely switch from the first mode to the second mode. Therefore, in the case of a hybrid heat treatment furnace, it is possible to quickly and surely switch from the gas mode to the electric mode. In the present invention, since the control characteristics of the follow-up phase, the convergence phase, and the stability phase can be adjusted separately, parameter adjustment according to the actual object is facilitated. In particular, by adjusting the switching time point from the tracking phase to the convergence phase and adjusting the operation amount in the convergence phase, it is possible to forcibly and directly shape the response waveform of the setting value tracking control, Even when a system with strong nonlinearity is a control target, it is possible to realize appropriate set value tracking control.

[Principle of the Invention]
The essential and concrete solution to the problems of conventional hybrid heat treatment furnaces is to get the operating time, that is, to settling, by linking the gas mode (combustion method) and the electric mode (electric method). It is to shorten the time. That is, drawing an ideal temperature rising trajectory in which the gas mode (combustion method) and the electric mode (electric method) work together to quickly raise the temperature from a low temperature to a high temperature and to settle quickly leads to a solution to the problem.

  In this case, in the series of operations, the manipulated value MV is maintained at a high value in the temperature raising operation by the gas mode (combustion method), and the manipulated value MV is maintained at a low value in the settling operation in the electric mode (electric method). Become. That is, it can be analyzed that it is appropriate to design as a series of temperature rising and setting operations in which the operation amount band is separated.

  Therefore, the inventor has a discontinuous manipulated variable output operation in the control device disclosed in Japanese Patent Application Laid-Open No. 2003-208201, and the transition from the follow phase to the converged phase is a discontinuous manipulated variable output operation. It was noted that it is similar to the temperature rising settling operation. Then, the inventors came up with the idea that it is appropriate to switch the heating method at the timing of shifting from the follow-up phase to the convergence phase. That is, the follow-up phase may be operated in the gas mode (combustion method) and the convergence phase and the stability phase may be operated in the electric mode (electric method).

[Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a waveform diagram showing the operation of the control device according to the embodiment of the present invention, FIG. 1 (A) shows a change in the control amount PV, and FIG. 1 (B) shows a change in the manipulated variable MV. FIG. ○ marks in FIG. 1 (B) is a manipulated variable MV output every control cycle dt. In the present embodiment, the response process of the set value tracking control accompanying the change of the set value is divided into the following three phases (following phase, convergence phase, and stable phase).

  First, in the response process, a follow-up phase is set from a set value SP change start time t1 to a specific set value follow-up control elapsed time t2 at which the control amount PV does not exceed the set value SP. In this follow-up phase, the operation amount MV is continuously output so that the response waveform of the set value follow-up control is not disturbed and the control amount PV follows the set value SP. Next, the convergence phase is set from the specific set value follow-up control elapsed time t2 to the time t3 at which a predetermined condition is reached. In this convergence phase, the manipulated variable MV is continuously output so that the response waveform of the set value follow-up control is not disturbed and the controlled variable PV converges near the set value SP. Then, the time t3 or later after reaching the previously specified situation is set as the stable phase. In this stable phase, the manipulated variable MV is continuously output so that the controlled variable PV is stabilized at the set value SP.

  FIG. 2 is a block diagram showing a configuration of the control device according to the present embodiment. The control device includes a set value input unit 1 for inputting a set value SP set by an operator of the control device, a control amount input unit 2 for inputting a control amount PV detected by a sensor (not shown), and a setting value change start time. The first phase switching unit 3 that switches to the follow-up phase with the start phase t1 of the follow-up phase, and the start of the convergence phase when the control amount PV does not exceed the set value SP in the follow-up phase A second phase switching unit 4 for switching to the convergence phase at time t2, and a third phase for switching to the stable phase with a time point when reaching a preset condition in the convergence phase as a start time t3 of the stable phase A switching unit 5 and a predetermined operation amount MV for causing the control amount PV to follow the set value SP in the follow-up phase. A first manipulated variable determining unit 6 that outputs continuously, and a second manipulated variable determiner that continuously outputs a predefined manipulated variable MV for converging the controlled variable PV near the set value SP in the convergence phase. Unit 7, a third manipulated variable determining unit 8 that continuously outputs a predefined manipulated variable MV for stabilizing the controlled variable PV at the set value SP in the stability phase, and a hybrid heat treatment furnace in the follow-up phase. A gas mode manipulated variable output unit 9 for outputting the manipulated variable MV output from the first manipulated variable determining unit 6 to the first operating means operated as a gas combustion furnace, and a hybrid heat treatment furnace in the convergence phase or the stable phase The electric operation amount output unit outputs the operation amount MV output from the second operation amount determination unit 7 or the third operation amount determination unit 8 to the second operation means that operates the electric furnace as an electric furnace. And a part 10.

  The temperature control system to which the control device of the present embodiment is applied is as shown in FIG. The control device is provided inside the temperature controller 104 of FIG. The gas heater 102 and the gas flow rate regulator 106 constitute a first operation means, and the electric heater 101 and the power regulator 105 constitute a second operation means.

Hereinafter, the operation of the control device of the present embodiment will be described. FIG. 3 is a flowchart showing the operation of the control device.
The set value SP is set by an operator of the control device, and the first phase switching unit 3, the second phase switching unit 4, the third phase switching unit 5 and the first operation amount are set via the set value input unit 1. The data is input to the determination unit 6, the second operation amount determination unit 7, and the third operation amount determination unit 8. The control amount PV is detected by a sensor (temperature sensor 103 in the example of FIG. 6), and the first phase switching unit 3, the second phase switching unit 4, and the third phase switching unit via the control amount input unit 2. 5. Input to the first manipulated variable determiner 6, the second manipulated variable determiner 7, and the third manipulated variable determiner 8.

  In the initial state, the stable phase is selected. That is, with the start of control, the first phase switching unit 3 determines whether or not the follow-up phase start time t1 (step S101 in FIG. 3), and if it is determined that it is not the start time t1, phase switching is not performed. In step S107, the stable phase is maintained. In the stable phase, the third operation amount determination unit 8 outputs a predetermined operation amount MV, and the electric mode operation amount output unit 10 outputs the operation amount MV output from the third operation amount determination unit 8. Output to the control target (the actual output destination is the power regulator 105) (step S107). However, as is clear from FIG. 1B, the manipulated variable MV output in the initial state is, for example, 0%, which is different from the manipulated variable MV output when the convergence phase is switched to the stable phase.

  When it is determined that the follow-up phase start time t1 is determined by changing the set value SP as shown in FIG. 1A (YES in step S101), the first phase switching unit 3 starts from the stable phase to the follow-up phase. The second phase switching unit 4, the third phase switching unit 5 and the first manipulated variable determination unit 6 are notified of the switching to the follow phase. In the follow-up phase, the first operation amount determining unit 6 outputs a predetermined operation amount MV, and the gas mode operation amount output unit 9 outputs the operation amount MV output from the first operation amount determining unit 6. Output to the control target (the actual output destination is the gas flow rate regulator 106) (step S102).

  Next, when the phase is switched to the follow-up phase, the second phase switching unit 4 determines whether or not it is the start time t2 of the convergence phase (step S103), and when it is determined that it is not the start time t2, the phase is switched. Without returning to step S102, the follow-up phase is maintained.

  If it is determined in step S103 that the convergence phase start time t2 is reached, the second phase switching unit 4 switches from the follow-up phase to the convergence phase, and the first phase switching unit 3 and the second phase switching unit 4 switch to the convergence phase. 3 to the phase switching unit 5 and the second operation amount determination unit 7. In the convergence phase, the second operation amount determination unit 7 outputs a predetermined operation amount MV, and the electric mode operation amount output unit 10 outputs the operation amount MV output from the second operation amount determination unit 7. Output to the controlled object (step S104).

  Next, when the phase is switched to the convergence phase, the first phase switching unit 3 determines whether or not it is the follow-up phase start time t1 (step S105). Then, the convergence phase is switched to the tracking phase, and the second phase switching unit 4, the third phase switching unit 5 and the first manipulated variable determination unit 6 are notified of the switching to the tracking phase. If the first phase switching unit 3 determines that it is not the start time t1, the first phase switching unit 3 proceeds to step S106 without performing phase switching and remains in the convergence phase.

  Subsequently, the third phase switching unit 5 determines whether or not it is the start time t3 of the stable phase (step S106). If it is determined that it is not the start time t3, the third phase switching unit 5 returns to step S104 without performing phase switching and returns to the convergence phase. Leave as it is.

  In step S106, when it is determined that the start time t3 of the stable phase, the third phase switching unit 5 switches from the convergence phase to the stable phase, and the first phase switching unit 3, To the second phase switching unit 4 and the third operation amount determination unit 8. In the stable phase, the third operation amount determination unit 8 outputs a predetermined operation amount MV, and the electric mode operation amount output unit 10 outputs the operation amount MV output from the third operation amount determination unit 8. Output to the controlled object (step S107). The processes in steps S101 to S107 as described above are repeated every control cycle dt until the control device is stopped by an instruction from an operator or the like (YES in step S108).

  Here, phase switching will be described in more detail. FIG. 4 is a waveform diagram for explaining switching from the follow-up phase to the convergence phase. The second phase switching unit 4 uses the predicted value Tr of the remaining arrival time, which is the time from the control amount PV in the current control cycle to the set value SP, and the deviation Er between the set value SP and the control amount PV and the control amount. Based on the PV change rate ΔPV, Tr = Er / ΔPV is calculated, and the time when the calculated estimated remaining arrival time Tr becomes smaller than a preset time index Tx is defined as the convergence phase start time (specific setting The value follow-up control elapsed time) is determined to be t2, and the follow-up phase is switched to the convergence phase.

  FIG. 5 is a waveform diagram for explaining switching from the convergence phase to the stable phase. The third phase switching unit 5 determines the time when the preset time index Tc has elapsed from the start time t2 of the convergence phase as the start time of the stable phase (time to reach a predetermined condition) t3. Switching from the convergence phase to the stable phase is performed.

  Next, the operation amount determination procedure in each phase will be described. There are three operation amount determination procedures in the follow-up phase. According to the first procedure, the first operation amount determination unit 6 outputs a preset operation amount MV1. According to the second procedure, the first operation amount determination unit 6 performs time delay filter processing on the preset operation amount MV1 and outputs a value MVf after the time delay filter processing. According to the third procedure, the first manipulated variable determiner 6 calculates the manipulated variable MVc from the deviation Er by a PID control algorithm (including P, PD, and PI control) that emphasizes control responsiveness. Output.

In the convergence phase, the second manipulated variable determiner 7 outputs a preset manipulated variable MV2.
In the stable phase, the third manipulated variable determiner 8 calculates and outputs the manipulated variable MVd from the deviation Er by a PID control algorithm (including P, PD, and PI control) that emphasizes control stability.

  In the present embodiment, control is performed by a method that gives different control characteristics to the follow-up phase and the stable phase, and the control response waveform is not disturbed before and after switching between the follow-up phase and the stable phase. In addition, a convergence phase is provided for performing control by giving yet another control characteristic. In the follow-up phase, the manipulated variable MV is output only for the purpose of causing the control amount PV to follow the set value SP. Next, in the convergence phase, in order to shift from the follow-up phase to the stable phase, an operation amount MV for the purpose of only converging the control amount PV near the set value SP is output. Finally, in the stable phase, the manipulated variable MV is output only for the purpose of stabilizing the controlled variable PV at the set value SP.

  In the present embodiment, since the control characteristics of the follow-up phase, the convergence phase, and the stability phase can be adjusted separately, it is easy to adjust parameters according to the actual object. In particular, in the setpoint tracking control, the response waveform of the setpoint tracking control is forcibly and directly shaped by adjusting the switching point from the tracking phase to the convergence phase and adjusting the manipulated variable MV in the convergence phase. Therefore, clean set value tracking control can be realized.

Next, a more specific operation of this embodiment will be described with reference to FIGS. As described above, the processing in steps S101 to S108 in FIG. 3 is performed every control cycle dt. Therefore, the operation amount MV is also output every control cycle dt.
In the present embodiment, the parameter indicating the phase is F, the tracking phase when F = 1, the convergence phase when F = 2, and the stable phase when F = 3. Further, the set value in the current control cycle n is SP (n), the control amount in the control cycle n is PV (n), the operation amount in the control cycle n is MV (n), and the control deviation in the control cycle n is Er (n ).

  If the set value SP (n) in the current control cycle n is larger than the set value SP (n−1) in the previous control cycle in step S101 or S105 in FIG. Is determined as the start time t1 of the follow-up phase, and the value of the parameter F indicating the phase is set to F = 1 (follow-up phase), and this F = 1 is set to the second phase switch unit 4, the third phase switch unit 5 and the second phase switch unit 5 1 to the operation amount determination unit 6. When the first phase switching unit 3 receives a notification of F = 2 or F = 3 from the second phase switching unit 4 or the third phase switching unit 5, the first phase switching unit 3 The value of the parameter F being output is changed to the received value F = 2 or F = 3.

When the value of the parameter F output from the first phase switching unit 3 is F = 1, the first operation amount determination unit 6 operates the operation amount MVc ( n) is output as the manipulated variable MV (n) (step S102 in FIG. 3, FIG. 1B). Here, a PID control algorithm that emphasizes control responsiveness is expressed by the following equation when expressed by a transfer function using a Laplace operator s.
MVc (n) = Kg1 {1+ (1 / Ti1s) + Td1s} {SP (n)
-PV (n)} (1)

  In Expression (1), Kg1 is a proportional gain, Ti1 is an integration time, and Td1 is a differentiation time. Since the method of setting the parameters Kg1, Ti1, and Td1 for emphasizing responsiveness is well known, the description thereof is omitted. Here, although the said 3rd procedure is employ | adopted as an operation amount determination procedure in a follow-up phase, it cannot be overemphasized that a 1st procedure or a 2nd procedure may be employ | adopted.

Next, the second phase switching unit 4 calculates a deviation Er (n) = SP (n) −PV (n) between the set value SP (n) and the control amount PV (n) in the current control cycle n. To do. Further, the second phase switching unit 4 calculates the predicted arrival time Tr (n), which is the time from the control amount PV (n) in the current control cycle n to the set value SP, as shown in the following equation. calculate.
Tr (n) = Er (n) / ΔPV
= Er (n) dt / {PV (n) -PV (n-1)} (2)
In the formula (2), PV (n−1) is a control amount before one control cycle.

  The second phase switching unit 4 is preset with a time index Tx for determining phase switching. In step S103 of FIG. 3, the second phase switching unit 4 has a parameter F value of F = 1, the set value SP (n) has not been changed from the set value SP (n−1), and has reached. When the remaining time prediction value Tr (n) is smaller than the time index Tx, the value of the parameter F is set to F = 2 (convergence phase), and F = 2 is set as the first phase switching unit 3 and the third phase switching unit. 5 and the second manipulated variable determiner 7. When the second phase switching unit 4 receives a notification of F = 1 or F = 3 from the first phase switching unit 3 or the third phase switching unit 5, the second operation amount determining unit 7 The value of the parameter F being output is changed to the received value F = 1 or F = 3.

  Next, the operation amount output value MV2 in the convergence phase is preset in the second operation amount determination unit 7. When the value of the parameter F output from the second phase switching unit 4 is F = 2, the second operation amount determination unit 7 outputs a preset value MV2 as the operation amount MV (n) ( FIG. 3 step S104, FIG. 1 (B)).

  Next, the third phase switching unit 5 is preset with a time index Tc for phase switching determination. The third phase switching unit 5 determines that the elapsed time tn from the time t2 when the value of the parameter F is set to F = 2 and F = 2 (convergence phase) in step S106 of FIG. If it is too long, the present time is determined as the start time t3 of the stable phase, the value of the parameter F is set to F = 3 (stable phase), and F = 3 is set to the first phase switching unit 3 and the second phase switching unit 4. And output to the third manipulated variable determiner 8. When the third phase switching unit 5 receives a notification of F = 1 or F = 2 from the first phase switching unit 3 or the second phase switching unit 4, the third phase switching unit 5 The value of the parameter F being output is changed to the received value F = 1 or F = 2.

Next, when the value of the parameter F output from the third phase switching unit 5 is F = 3, the third operation amount determination unit 8 performs an operation calculated by a PID control algorithm that places importance on control stability. The amount MVd (n) is output as the manipulated variable MV (n) (step S107 in FIG. 3, FIG. 1B). Here, the PID control algorithm that places importance on the stability of the control is expressed by the following equation when expressed by a transfer function.
MVd (n) = Kg3 {1+ (1 / Ti3s) + Td3s} {SP (n)
-PV (n)} (3)
In Equation (3), Kg3 is a proportional gain, Ti3 is an integration time, and Td3 is a differentiation time. Since the method of setting the parameters Kg3, Ti3, and Td3 for emphasizing stability is well known, a description thereof will be omitted.

  Note that the method of setting the manipulated variable output value MV1 and the filter time constant when the first and second procedures are adopted as the manipulated variable determining procedure in the follow-up phase is disclosed in Japanese Patent Laid-Open No. 2003-208201. Yes. Similarly, the method of setting the time indexes Tx and Tc and the manipulated variable output value MV2 is disclosed in Japanese Patent Laid-Open No. 2003-208201.

  In the temperature control system in the hybrid heat treatment furnace shown in FIG. 6, the electric heater 101 for performing high-precision control exists at a position close to the temperature sensor 103, and the gas heater 102 exists at a position far from the electric heater 101. doing. As a result, the dead time L until the output change of the electric heater 101 is reflected in the temperature measured by the temperature sensor 103 is shorter than the dead time L of the gas heater 102.

  On the other hand, the electric heater 101 is slow in changing the heat generation state in response to the operation amount MV which is a command from the control device. Technically, the time constant T is not long, but the time constant T is long. On the other hand, since the gas heater 102 generates heat by the combustion of gas, the speed at which the heat generation state changes in response to the operation amount MV is rapid. Technically, the time constant T is short.

  That is, since the electric heater 101 has a small dead time / time constant ratio (L / T ratio), it is easy to perform PID adjustment that emphasizes responsiveness, and the gas heater 102 has a larger L / T ratio than the electric heater 101. It must be adjusted for stability. That is, it takes time to reach the final settling by using the gas heater 102 which must give priority to stability at the expense of quick response.

In the present embodiment, it is avoided that the gas heater 102 reaches the final settling, and the heating function is switched aiming at a point where the manipulated variable MV becomes discontinuous in a series of temperature raising operations. In other words, continuous manipulated variable output is performed to obtain an ideal temperature rise trajectory, but the point at which the only manipulated variable output is discontinuous coincides with the discontinuous point of the heating function. I am letting.
Thus, in the present embodiment, it is possible to quickly and surely switch from the gas mode to the electric mode.

  Note that, according to the third procedure among the operation amount determination procedures in the follow-up phase, the first operation amount determination unit 6 calculates the operation amount MV by the PID control algorithm, but the present invention is not limited to this. Other control algorithms such as (Internal Model Control) may be used. Similarly, another control algorithm may be used in the third operation amount determination unit 8.

  The control device according to the present embodiment can be realized by a computer having a CPU, a storage device, and an interface, and a program that controls these hardware resources. The CPU executes the processing described in the present embodiment in accordance with a program stored in the storage device.

  The present invention can be applied, for example, to temperature rise control of a hybrid heat treatment furnace including a gas combustion furnace and an electric furnace.

It is a wave form diagram which shows operation | movement of the control apparatus which concerns on embodiment of this invention. It is a block diagram which shows the structure of the control apparatus which concerns on embodiment of this invention. It is a flowchart which shows operation | movement of the control apparatus which concerns on embodiment of this invention. It is a wave form diagram for explaining switching from a follow phase to a convergence phase. It is a wave form diagram for explaining switching from a convergence phase to a stable phase. It is a figure which shows one example of the temperature control system in a hybrid type heat processing furnace.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Setting value input part, 2 ... Control amount input part, 3 ... 1st phase switching part, 4 ... 2nd phase switching part, 5 ... 3rd phase switching part, 6 ... 1st manipulated variable determination part , 7... Second operation amount determination unit, 8... Third operation amount determination unit, 9... Gas mode operation amount output unit, 10.

Claims (6)

First phase switching means for switching to the follow-up phase with the set value change start time as the start time of the follow-up phase;
Second phase switching means for switching to the convergence phase with a specific set value tracking control elapsed time at which the control amount does not exceed a set value in the tracking phase as a convergence phase start time;
Third phase switching means for switching to the stable phase with the time when a preset situation is reached in the convergence phase as the start time of the stable phase;
First operation amount determination means for continuously outputting an operation amount for causing the control amount to follow a set value in the following phase;
A second manipulated variable determining means for continuously outputting an manipulated variable for converging the controlled variable in the vicinity of a set value in the convergence phase;
A third operation amount determination means for continuously outputting an operation amount for stabilizing the control amount at a set value in the stable phase;
A first operation for operating a control target having two operation modes of a first mode excellent in energy efficiency and a second mode superior in control responsiveness than the first mode in the first mode. A first operation amount output means for outputting the operation amount output from the first operation amount determination means in the follow-up phase;
The operation amount output from the second operation amount determination unit or the third operation amount determination unit in the convergence phase and the stability phase is output to the second operation unit that operates the control target in the second mode. And a second operation amount output means. The control device according to claim 1,
The control object is a hybrid heat treatment furnace of a gas combustion furnace and an electric furnace, the first mode is a gas mode that operates as a gas combustion furnace, and the second mode is an electric that operates as an electric furnace. A control device characterized by being in a mode. The control device according to claim 1,
In the follow-up phase, the second phase switching means converts the predicted arrival time, which is the time from the current control amount to the set value, into the deviation between the set value and the control amount and the change rate of the control amount. A control device characterized in that a time point when the calculated predicted remaining arrival time becomes smaller than a preset time index is set as a start point of the convergence phase. A first phase switching procedure for switching to the follow-up phase with the set value change start time as the start time of the follow-up phase;
An operation amount determination procedure in the follow phase that continuously outputs an operation amount that causes the control amount to follow the set value in the follow phase;
A first operation for operating a control target having two operation modes of a first mode excellent in energy efficiency and a second mode superior in control responsiveness than the first mode in the first mode. Means for outputting an operation amount in the follow-up phase for outputting the operation amount determined in the operation amount determination procedure in the follow-up phase;
A second phase switching procedure for switching to the convergence phase with a specified setpoint tracking control elapsed time at which the control amount does not exceed a set value in the tracking phase as a start time of the convergence phase;
An operation amount determination procedure in a convergence phase for continuously outputting an operation amount for converging the control amount in the vicinity of a set value in the convergence phase;
An operation amount output procedure in a convergence phase for outputting the operation amount determined in the operation amount determination procedure in the convergence phase to second operation means for operating the control target in the second mode;
A third phase switching procedure for switching to the stable phase with the time point when reaching a preset situation in the convergence phase as the start point of the stable phase;
An operation amount determination procedure in a stable phase for continuously outputting an operation amount that stabilizes the control amount to a set value in the stable phase;
A control method comprising: a stable phase manipulated variable output procedure for outputting the manipulated variable determined by the stable phase manipulated variable determining procedure in the second operating means. The control method according to claim 4, wherein
The control object is a hybrid heat treatment furnace of a gas combustion furnace and an electric furnace, the first mode is a gas mode that operates as a gas combustion furnace, and the second mode is an electric that operates as an electric furnace. A control method characterized by being in a mode. The control method according to claim 4, wherein
In the second phase switching procedure, the predicted value of the remaining arrival time, which is the time until the set value is reached from the current controlled variable in the follow-up phase, is converted into the deviation between the set value and the controlled variable and the change rate of the controlled variable. A control method characterized in that a time point at which the predicted arrival remaining time value calculated based on the calculated time is smaller than a preset time index is set as a start point of the convergence phase.

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