JP2006221235A - Controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To relax the saturation of manipulated variables, and to prevent such effects that a status quantity difference as an original purpose is reduced from being damaged in performing control so that the status quantity difference can be made small. <P>SOLUTION: This controller comprises a status quantity measurement value converting part 5 for converting the status quantity measurement value of each control loop into a value obtained by linearly connecting respective status quantity measurement values by a status quantity conversion matrix; PID control arithmetic parts 6-1 to 6-3 for calculating the manipulated variables of the respective control loops based on a control deviation between the converted status quantity measurement value and a corresponding status quantity setting value; a manipulated variable converting part 7 for converting the calculated n pieces of manipulated variables so that those manipulated variables can be distributed to the respective control loops by the manipulated quantity conversion matrix; and status quantity filtering setting value calculating parts 3-1 to 3-3 for operating filtering processing for suppressing rapid fluctuation to the status quantity setting value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a process control technique, and more particularly to a control device that controls a state quantity difference measured in a control system having at least two control loops.

  FIG. 5A shows the configuration of a temperature controller that is a conventional control device (see, for example, Patent Document 1). A heat treatment work 1016 is carried into the furnace 1001, and the heater 1011, detection means 1012 for detecting the control temperature TC 1, detection means 1013 for detecting the surface temperature TC 2 of the work 1016, and the deepest temperature TC 3 of the work 1016. Detection means 1014 for detecting is arranged. Reference numeral 1002 denotes a power regulator. The control unit 1003 includes a comparator 1031 that compares the control temperature TC1 and the execution program pattern set value 1033, a control calculation unit 1032 such as PID controlled by the output of the comparator 1031, and the surface temperature TC2 of the workpiece 1016 and the deepest surface temperature TC2. A temperature difference detector 1034 that detects a difference from the temperature TC3, a temperature difference setter 1035 that sets a predetermined temperature difference, and an output of the temperature difference detector 1034 and an output of the temperature difference setter 1035 are compared. The comparator 1036, the change rate detector 1038 for detecting the temperature change rate of the deepest temperature TC3, and the output of the change rate detector 1038 are compared with the output of the change rate setter 1039 for setting a predetermined temperature change rate. The comparator 1040 to perform, the inclination calculation based on the output of the comparator 1036 and the output of the comparator 1040, and the execution program pattern set value 103 And an inclined calculator 1037 for controlling.

The maximum allowable temperature difference is set in the temperature difference setting unit 1035, and the maximum allowable temperature change rate is set in the change rate setting unit 1039. With the configuration of FIG. 5A, the gradient in the execution program pattern set value 1033 is constantly corrected so that one or both of the temperature difference and the temperature change rate in the heat-treated workpiece 1016 are within the specified temperature tolerance. The
Focusing on the portion surrounded by the broken line in FIG. 5A, the state quantity for calculating the temperature difference (TC2-TC3) and the temperature change rate dTC3 / dt based on the measured temperatures TC1, TC2, TC3. You can see that the conversion is taking place. That is, the temperature controller of FIG. 5A includes the state quantity conversion unit 1041 that calculates the temperature difference (TC2−TC3) and the temperature change rate dTC3 / dt (FIG. 5B).

  FIG. 6 (a) shows a configuration of a temperature control device which is another conventional control device (see, for example, Patent Document 2). In the figure, reference numeral 2002 denotes a reaction tube of the vertical heat treatment apparatus 2020. Inside the reaction tube 2002, a temperature sensor A for detecting the temperature in the vicinity of the semiconductor wafer mounted on the wafer board 2021 is provided. A temperature sensor B that detects the temperature of the outer surface of the reaction tube 2002 is provided. The deviation circuit unit 2031 outputs a deviation obtained by subtracting a correction value described later from the target value of the temperature sensor A, that is, the target value of the temperature sensor B. The deviation circuit unit 2032 outputs a deviation obtained by subtracting the detection value of the temperature sensor B from the target value of the temperature sensor B to the PID adjustment unit 2004. The PID adjustment unit 2004 performs PID calculation based on the input deviation and outputs the calculation result to the power control unit 2005. The power control unit 2005 uses the vertical heat treatment apparatus based on the output value of the PID adjustment unit 2004. The power supply amount to the heater 2006, which is a heating source of 2020, is controlled. On the other hand, when the detected value of the temperature sensor B converges to the target value, the correction value output unit 2007 calculates the difference (A−B) between the detected value of the temperature sensor A and the detected value of the temperature sensor B at the time of convergence. As a correction value, the target value of the temperature sensor B is corrected by the correction value. With the configuration of FIG. 6A, the detection value of the temperature sensor A converges to the target value.

When attention is paid to a portion surrounded by a broken line in FIG. 6A, it is understood that state quantity conversion for calculating a temperature difference (A−B) based on a plurality of measured temperatures A and B is performed. it can. That is, the temperature adjustment device in FIG. 6A includes the state quantity conversion unit 2008 that calculates the temperature difference (A−B) (FIG. 6B).
As described above, efforts have been made in the past to incorporate not only the actual state quantity itself but also the state quantity difference into the control system. The state quantity conversion unit is provided.

  Here, in the normal two control loops (a combination of the controller, the actuator, and the measuring means), the state quantity average value PV1 ′ and the state quantity difference PV2 ′ are controlled, not the state quantities PV1 and PV2 themselves. think of. The control device in this case is shown in FIG. 7 includes a subtractor 3001 that outputs a difference between the set value SP1 ′ and the state quantity average value PV1 ′ with respect to the state quantity average value PV1 ′, and a set value SP2 ′ and the state quantity difference with respect to the state quantity difference PV2 ′. Subtractor 3002 that outputs a difference from PV2 ′, controllers C1 and C2 that calculate operation amounts MV1 ′ and MV2 ′ based on outputs from subtractors 3001 and 3002, and control target processes P1 and P2, respectively. Actuators A1 and A2 that perform operations according to the operation amounts MV1 ′ and MV2 ′, and a state amount conversion unit 3003 are provided.

The state quantity conversion unit 3003 multiplies multipliers 3004 and 3005 for multiplying the state quantities PV1 and PV2 of the control target processes P1 and P2 by 0.5 and −1 and 1 respectively for the state quantities PV1 and PV2. Multipliers 3006 and 3007 for multiplication, an adder 3008 for adding the outputs of the multipliers 3004 and 3005, and an adder 3009 for adding the outputs of the multipliers 3006 and 3007. By such a state quantity conversion unit 3003, the state quantity average value PV1 ′ and the state quantity difference PV2 ′ are expressed by the following equations.
PV1 ′ = 0.5PV1 + 0.5PV2 (1)
PV2 ′ = PV2-PV1 (2)
Further, the input / output relationship of the state quantity conversion unit 3003 is expressed as a matrix as follows.

  The controller C1 targets the state quantity average value PV1 ', and the controller C2 targets the state quantity difference PV2'. The controller C1 calculates the operation amount MV1 ′ based on the deviation between the set value SP1 ′ and the state quantity average value PV1 ′, and the controller C2 calculates the operation quantity MV2 based on the deviation between the set value SP2 ′ and the state quantity difference PV2 ′. 'Is calculated. At this time, since the state quantity average value PV1 ′ and the state quantity difference PV2 ′ are in a controllable state, the operation amount MV1 ′ calculated by the controller C1 is sent to the actuator A1 and calculated by the controller C2. The operation amount MV2 ′ is configured to be sent to the actuator A2. As a result, the actuator A1 operates to control the state quantity average value PV1 ', and the actuator A2 operates to control the state quantity difference PV2'. In this way, the controller C1 that directly controls the state quantity average value PV1 ′ and the state quantity difference PV2 are simply applied by applying a state quantity conversion unit 3003 similar to that shown in FIGS. 5B and 6B. A multi-loop control system including a controller C2 that directly controls' can be configured, and the state quantity average value PV1 'and the state quantity difference PV2' can be controlled to desired values.

  However, when the state quantity PV1 is changed by the operation of the actuator A1, this change also affects the state quantity difference PV2 'by the action of the state quantity conversion unit 3003. Similarly, when the state quantity PV2 is changed by the operation of the actuator A2, this change also affects the state quantity average value PV1 'by the action of the state quantity conversion unit 3003. That is, in the control device shown in FIG. 7, the state quantity conversion unit 3003 artificially generates inter-loop interference. In addition, when there is interference between the loops in the two control loops, more complicated inter-loop interference occurs, resulting in a problem that controllability is likely to deteriorate.

  Therefore, in order to realize non-interference between loops, it is easily conceivable to apply the cross controller disclosed in Non-Patent Document 1. The configuration of the control device disclosed in Non-Patent Document 1 is shown in FIG. 8 includes a subtractor 4001 that outputs a difference between the set value SP1 and the state quantity PV1, a subtractor 4002 that outputs a difference between the set value SP2 and the state quantity PV2, and outputs of the subtractors 4001 and 4002. Controller 4003 and 4004 for calculating the operation amounts MV1 ′ and MV2 ′, respectively, and a cross controller 4005 for outputting the operation amounts MV1 and MV2 obtained by converting the operation amounts MV1 ′ and MV2 ′, respectively.

  The cross controller 4005 performs processing for previously canceling the influence due to the interference between the loops on the manipulated variables MV1 ′ and MV2 ′, a multiplier 4007 for multiplying the manipulated variable MV1 ′ by a coefficient M12, and an manipulated variable MV2 ′. A multiplier 4008 that multiplies the output by the coefficient M21, a subtracter 4009 that outputs the difference between the manipulated variable MV1 ′ and the output of the multiplier 4008 as the manipulated variable MV1, and a difference between the manipulated variable MV2 ′ and the output of the multiplier 4007. And a subtractor 4010 that outputs the manipulated variable MV2. Here, for simplicity of explanation, dynamic characteristics such as process time constant and process dead time are ignored. First, the inter-loop interference originally occurring in the above two control loops is assumed as follows.

  The relationship between the manipulated variables MV1 and MV2, the state quantity average value PV1 ', and the state quantity difference PV2' is as follows.

  According to Non-Patent Document 1, the cross controller 4005 for non-interference can be designed as follows.

  From the equation (6), the coefficient M12 is −1.0 and the coefficient M21 is 1.0. The operation amount MV1 ′ calculated by the controller 4003 is converted to the operation amount MV1 by the cross controller 4005 and then sent to the control target process 4006 via an actuator (not shown). The operation amount MV2 ′ calculated by the controller 4004 is After being converted into the operation amount MV2 by the cross controller 4005, it is sent to the control target process 4006 via the actuator.

  FIG. 9 shows a configuration in which the cross controller 4005 shown in FIG. 8 is applied to the control device of FIG. From equations (5) and (6), the relationship between the manipulated variables MV1 'and MV2' from the controllers C1 and C2, the state quantity average value PV1 ', and the state quantity difference PV2' is as follows.

  In Equation (7), the matrix portion is a diagonal matrix, and no mutual interference occurs between MV1 'and MV2' and PV1 'and PV2'. This decoupling is an essential effect of the cross controller. Therefore, the controller C1 for calculating the operation amount MV1 ′ is independently operated as a dedicated controller for controlling the state amount average value PV1 ′, and the controller C2 for calculating the operation amount MV2 ′ is exclusively used for controlling the state amount difference PV2 ′. It becomes possible to operate independently as a controller.

  As a device that uses substantially the same method as the control device shown in FIG. 8, there is a control device that uses a gradient temperature control method (see, for example, Patent Document 3). The configuration of the control device disclosed in Patent Document 3 is shown in FIG. The control apparatus in FIG. 10 includes a temperature regulator 5001 that controls the temperature of the process to be controlled 5002. The temperature regulator 5001 is the temperature (state quantity) of the process to be controlled 5002 measured by a plurality of temperature sensors (not shown). Mean temperature / gradient temperature calculation means 5003 for calculating an average temperature (state quantity average value) PV1 ′ and a gradient temperature (state quantity difference) PV2 ′ from PV1 and PV2, a state quantity average value PV1 ′, and a state quantity difference PV2 ′. Controller 5004, 5005 for calculating the operation amounts MV1 ′, MV2 ′ based on the above, and a distribution means 5006 for distributing the operation amounts MV1 ′, MV2 ′ to the actuators (not shown) at a predetermined distribution ratio.

  Here, the inter-loop interference originally occurring in the two control loops is assumed to be the same as in the equation (4), and the relationship between the manipulated variables MV1 and MV2 and the state quantity average value PV1 ′ and the state quantity difference PV2 ′ is as follows. It is the same as equation (5). According to Patent Document 3, the distribution unit 5006 can be designed as follows using the inverse matrix of the matrix portion of Equation (5).

  The operation amount MV1 ′ calculated by the controller 5004 is converted to the operation amount MV1 by the distribution unit 5006 and then sent to the control target process 5002 via an actuator (not shown). The operation amount MV2 ′ calculated by the controller 5005 is After being converted into the operation amount MV2 by the distribution unit 5006, it is sent to the control target process 5002 via the actuator. From the equations (5) and (8), the relationship between the operation amounts MV1 'and MV2' from the controllers 5004 and 5005, the state amount average value PV1 ', and the state amount difference PV2' is as follows.

  Also in Equation (9), the matrix portion is a diagonal matrix, and no mutual interference occurs between MV1 'and MV2' and PV1 'and PV2'. This decoupling is an essential effect of gradient temperature control. Therefore, the controller 5004 that calculates the operation amount MV1 ′ is independently operated as a dedicated controller that controls the state amount average value PV1 ′, and the controller 5005 that calculates the operation amount MV2 ′ is dedicated to control the state amount difference PV2 ′. It becomes possible to operate independently as a controller.

The applicant has not yet found prior art documents related to the present invention by the time of filing other than the prior art documents specified by the prior art document information described in this specification.
JP-A-8-095647 JP-A-9-199491 Japanese Patent No. 3278807 Kazuo Hiroi, “Basics and Applications of Digital Instrumentation Control System”, Industrial Technology Co., Ltd., October 1987, p. 152-156, ISBN4-905957-00-1

  In the control device shown in FIGS. 9 and 10, the state quantity conversion unit 3003 or the average temperature / gradient temperature calculation means 5003 calculates the state quantity average value PV1 ′ and the state quantity difference PV2 ′. PV1 ′ is a reference state quantity corresponding to “reference absolute state quantity”, and state quantity difference PV2 ′ is a relative state quantity corresponding to “relative state quantity such as state quantity difference”. And if it can be moved up and down in the range which does not restrict | limit the operation amount, it is possible to control a relative state quantity (state quantity difference) as requested.

  However, when the operation amount saturation occurs, a situation in which the control cannot be performed as requested may occur. Hereinafter, problems of the conventional control device shown in FIGS. 9 and 10 will be described with reference to FIGS. 11 (a) and 11 (b). Here, there are three control loops I, II, and III, and the object of the control is to reduce the state quantity difference between the control loops. Further, the control algorithm of the controller of each control loop at this time is assumed to be PID. FIG. 11A shows a control response when a step input of the set value SP = 30% is added to the controllers of the control loops I, II, and III, and FIG. 11B shows each control at the time of this step input. The manipulated variable MV output from the controllers of the loops I, II, and III is shown.

  When step input of the set value SP is applied, the manipulated variable output MV changes greatly in normal PID calculation, and the state quantity PV changes in a direction to follow the set value SP. In order to control the state quantity difference as required in the transient state at this time, it is necessary that the manipulated variable MV is in the range of 0 to 100% and can be freely increased or decreased. However, in the conventional control device shown in FIGS. 9 and 10, an operation amount for controlling the state quantity average value is obtained by adding a step input to the set value SP ′ with respect to the state quantity average value (that is, the reference state quantity). When PID calculation is performed in a range where MV ′ greatly exceeds 100%, the manipulated variable MV that is finally output to the controlled object by the non-interacting process also physically remains saturated at the upper limit value of 100%. It becomes the situation of not doing. Therefore, the effect of reducing the state quantity difference cannot be obtained. As described above, the conventional control device has a problem that the original effect is impaired by the occurrence of the operation amount saturation.

  The present invention has been made in order to solve the above-described problem, and in the control system having at least two control loops, when controlling the state quantity difference to be small, the state quantity set value (especially the reference state quantity setting) is set. It is an object of the present invention to provide a control device that can alleviate the saturation of the manipulated variable that occurs at the time of step input of (value), and that can avoid losing the effect of reducing the state quantity difference that is the original purpose.

  According to the present invention, in a control system control device having n (n is a natural number of 2 or more) control loops, each state quantity measurement value of the n control loops is represented by each state by an n × n state quantity conversion matrix. A state quantity conversion unit that converts a quantity measurement value into a linearly combined value, and calculates an operation amount of each control loop based on a control deviation between each converted state quantity measurement value and each corresponding state quantity set value And the calculated n operation amounts are converted to be distributed to the operation amounts of each control loop by an n × n operation amount conversion matrix, and the converted n operation amounts correspond respectively. An operation amount conversion unit that outputs to a control target of a control loop that performs, and a state amount filtering set value calculation unit that performs filtering processing that suppresses sudden fluctuations on the state amount set value input to the control calculation unit It is.

Moreover, in one configuration example of the control device of the present invention, the state quantity conversion matrix includes a reference state quantity measurement that is an average of the state quantity measurement values of the n control loops in the converted state quantity measurement values. Value and a relative state quantity measurement value that gives a relative relationship between the state quantity measurement values of different control loops are included in advance, and the manipulated variable conversion matrix is controlled by each control calculation unit. This is set in advance so as to eliminate or reduce the influence on the control by the control calculation unit.
Moreover, in one structural example of the control apparatus of the present invention, the state quantity filtering set value calculation unit performs the filtering process by time delay calculation.
Further, in one configuration example of the control device of the present invention, the time constant of the filtering process is further changed to the change amount of the state amount set value so that the saturation of the operation amount output from the control arithmetic unit is alleviated. It is provided with the correction means which corrects according to it.
In one configuration example of the control device of the present invention, the manipulated variable conversion matrix is designed by a gradient temperature control method.
Further, in one configuration example of the control device of the present invention, the manipulated variable conversion matrix is designed by a cross controller design method.

  According to the present invention, each state quantity measurement value of the n control loops is converted into a value obtained by linearly combining each state quantity measurement value by an n × n state quantity conversion matrix, and each converted quantity A control operation unit that calculates an operation amount of each control loop based on a control deviation between the state amount measurement value and each state amount setting value corresponding thereto, and n × n operation amount conversion of the calculated n operation amounts. A plurality of state quantities are provided by providing an operation amount conversion unit that converts the n operation amounts converted into a control amount of each control loop according to a matrix and outputs the converted n operation amounts to the control target of the corresponding control loop. It is possible to realize control for changing the reference state quantity to a desired value while maintaining a relative state quantity such as a state quantity difference between them at a desired value. Furthermore, in the present invention, by performing a filtering process that suppresses sudden fluctuations on the state quantity set value, the saturation of the operation quantity is alleviated when controlling the relative quantity such as the state quantity difference to be small. It is possible to avoid losing the effect of reducing the state quantity difference, which is the original purpose.

[Principle of the Invention]
Hereinafter, in the present invention, an absolute state quantity serving as a reference, for example, a state quantity average value, is referred to as a reference state quantity, for example, a relative state quantity, such as a state quantity difference, is referred to as a relative state quantity. Also, the setting value for the reference state quantity is the reference state quantity setting value, the reference state quantity measurement value is the reference state quantity measurement value, the relative state quantity setting value is the relative state quantity setting value, and the relative state quantity measurement value is the relative state This is called a quantity measurement value. Examples of the state quantity include temperature, pressure, and flow rate.

  In the present invention, the cause of the problem of the conventional control device described with reference to FIGS. 11A and 11B is the differential kick unique to the PID control calculation that occurs when the set value SP is stepped. Pay attention. For example, when a sudden change in the set value SP acts on the differential operation of the PID, the manipulated variable MV also suddenly changes in a direction to follow the sudden change in the set value SP, and the manipulated variable saturation occurs. When the operation amount MV is saturated, the calculation of the operation amount MV by the PID control calculation is a situation where, for example, a value exceeding 100% of the operation amount upper limit value is increased or decreased. In this case, the vertical movement of the operation amount MV for reducing the state amount difference by the conventional control device is substantially removed by the operation amount saturation, and the effect of reducing the state amount difference cannot be obtained.

  In order to solve the problems of the conventional control device, the operation amount MV can be maintained as much as possible within a range that does not deviate from the upper and lower limit values of the operation amount (that is, 0 to 100%). do it. In particular, it is important that the differential kick is relaxed, and it is only necessary that the sudden change of the set value SP does not affect the PID control calculation or is sufficiently relaxed. Therefore, in the present invention, a filter that applies a damping effect to the change in the set value SP is applied. As this filter, a time delay filter having a simple structure such as a first-order delay and a second-order delay is suitable.

  As a filter setting method, there is a method in which the degree of occurrence of the manipulated variable saturation is examined in advance and, for example, the time constant of the first-order delay filter is appropriately set. However, this method is applicable only when the control operation occurs only in a pattern that can be seen in advance. More preferably, it should be possible to automatically correct the time constant of the first-order lag filter in response to the occurrence of operation amount saturation. If the cause of the manipulated variable saturation is a sudden change in the set value SP, the time constant of the first-order lag filter may be automatically corrected in conjunction with the change range of the set value SP, and the change range of the set value SP is large. Is a way to increase the time constant. More specifically, the time constant should be automatically corrected with reference to the manipulated variable MV value before changing the set value SP, the set PID parameter, and the like.

[Embodiment]
FIG. 1 is a block diagram showing a configuration of a control apparatus according to an embodiment of the present invention. In this embodiment, there are three control loops, the average value of the three control loops is used as the reference state quantity, and the difference between the three control loops is used as the relative state quantity. However, if two or more control loops are used, a similar control system can be configured based on the same principle.

  The control device in FIG. 1 includes a state quantity set value SP1 input unit 1-1, a state quantity measurement value PV1 input unit 2-1, and a state quantity filtering setting as the configuration of the first measurement system related to the first state quantity. A value SP1 ″ calculation unit 3-1, and a second measurement system configuration relating to the second state quantity includes a state quantity set value SP2 input unit 1-2, a state quantity measurement value PV2 input unit 2-2, And a state quantity filtering set value SP2 "calculating unit 3-2. As a configuration of a third measurement system relating to the third state quantity, a state quantity set value SP3 input unit 1-3 and a state quantity measured value PV3 input are provided. Unit 2-3 and state quantity filtering setting value SP3 ″ calculating unit 3-3.

  Further, the control device of FIG. 1 has a configuration relating to state quantity conversion, a state quantity set value conversion unit 4 that performs conversion of state quantity filtering set values using the state quantity conversion matrix T, and state quantity measurement using the state quantity conversion matrix T. And a state quantity measurement value conversion unit 5 that performs value conversion.

  In addition, the control device of FIG. 1 includes a PID control calculation unit (PID controller) 6-1 that calculates an operation amount MV1 ′ based on a reference state amount set value SP1 ′ and a measured value PV1 ′ as a configuration related to control, and a relative state. A PID control calculation unit 6-2 that calculates the operation amount MV2 ′ based on the amount setting value SP2 ′ and the measurement value PV2 ′, and a PID that calculates the operation amount MV3 ′ based on the relative state amount setting value SP3 ′ and the measurement value PV3 ′. A control calculation unit 6-3, an operation amount conversion unit 7 that performs operation amount conversion by the operation amount conversion matrix U, an operation amount MV1 output unit 8-1, an operation amount MV2 output unit 8-2, and an operation amount And an MV3 output unit 8-3.

  Further, the control device of FIG. 1 has a configuration related to the filter time constant adaptive correction, and when at least one of the state quantity set values SP1, SP2 and SP3 is changed, the reference state quantity set value SP1 ′ by this set value change is used. A set value change amount calculation unit 9 for calculating the change amount ΔSP1 ′ of the reference value, a change amount ΔSP1 ′ of the reference state amount set value SP1 ′ and a preset ratio α to calculate a filtering time constant Tf. A filtering time constant determination unit that sets the constant Tf in the state quantity filtering setting value SP1 "calculation unit 3-1, the state quantity filtering setting value SP2" calculation unit 3-2 and the state quantity filtering setting value SP3 "calculation unit 3-3. The set value change amount calculation unit 9 and the filtering time constant determination unit 10 are modified to modify the filtering time constant Tf. Constitute the stage.

  FIG. 2 is a block diagram of the control system in the present embodiment. A1 is an actuator that controls the first state quantity, A2 is an actuator that controls the second state quantity, A3 is an actuator that controls the third state quantity, P1 is a process to be controlled related to the first state quantity, P2 Is a control target process related to the second state quantity, P3 is a control target process related to the third state quantity, Gp1 is a transfer function of a block including the actuator A1 and the process P1, and Gp2 includes the actuator A2 and the process P2. A transfer function Gp3 of the block is a transfer function of the block including the actuator A3 and the process P3.

  State quantity set value SP1 input section 1-1, state quantity measurement value PV1 input section 2-1, state quantity filtering set value SP1 "calculation section 3-1, state quantity set value conversion section 4, and state quantity measurement The value conversion unit 5, the PID control calculation units 6-1, 6-2, 6-3, the operation amount conversion unit 7, the operation amount MV1 output unit 8-1, the actuator A1, and the process P1 A state quantity set value SP2 input unit 1-2, a state quantity measured value PV2 input unit 2-2, and a state quantity filtering set value SP2 "calculation unit are configured. 3-2, state quantity set value conversion unit 4, state quantity measurement value conversion unit 5, PID control calculation units 6-1, 6-2, 6-3, operation amount conversion unit 7, and operation amount MV2 The output unit 8-2, the actuator A2, and the process P2 include a second control system (second control loop). Constitute a. Then, the state quantity set value SP3 input section 1-3, the state quantity measured value PV3 input section 2-3, the state quantity filtering set value SP3 "calculation section 3-3, the state quantity set value conversion section 4, and the state The amount measurement value conversion unit 5, the PID control calculation units 6-1, 6-2, 6-3, the operation amount conversion unit 7, the operation amount MV3 output unit 8-3, the actuator A3, and the process P3 A third control system (third control loop) is configured.

  Next, the operation of the control device of the present embodiment will be described with reference to FIG. First, the state quantity measurement value PV1 is detected by a first detection unit (not shown) and input to the state quantity measurement value conversion unit 5 via the state quantity measurement value PV1 input unit 2-1 (step S101 in FIG. 3). . The state quantity measurement value PV2 is detected by a second detection unit (not shown) and is input to the state quantity measurement value conversion unit 5 via the state quantity measurement value PV2 input unit 2-2 (step S102). The state quantity measurement value PV3 is detected by a third detection unit (not shown), and is input to the state quantity measurement value conversion unit 5 via the state quantity measurement value PV3 input unit 2-3 (step S103).

  The state quantity set value SP1 is set by the operator of the control device, and is input to the state quantity filtering set value SP1 "calculating unit 3-1 and the set value change amount calculating unit 9 via the state quantity set value SP1 input unit 1-1. (Step S104) The state quantity set value SP2 is set by the operator, and the state quantity filtering set value SP2 "calculating unit 3-2 and the set value change amount are set via the state quantity set value SP2 input unit 1-2. The data is input to the calculation unit 9 (step S105). The state quantity set value SP3 is set by the operator, and is input to the state quantity filtering set value SP3 "calculating unit 3-3 and the set value change amount calculating unit 9 via the state quantity set value SP3 input unit 1-3. (Step S106).

The set value change amount calculation unit 9 detects the change amounts ΔSP1, ΔSP2, ΔSP3 of the changed set values SP1, SP2, SP3 when at least one of the state amount set values SP1, SP2, SP3 is changed. Then, the change amount ΔSP1 ′ of the reference state amount set value SP1 ′ due to the change of the set value is calculated as the following equation (step S107).
ΔSP1 ′ = (1/3) ΔSP1 + (1/3) ΔSP2 + (1/3) ΔSP3
... (10)
Of course, among the set value change amounts ΔSP1, ΔSP2, and ΔSP3 in Expression (10), the change amount is 0 for the set values that are not changed.

When the set value change amount calculation unit 9 detects a change in the set value, the filtering time constant determination unit 10 calculates the filtering time constant Tf as the following equation, and the filtering time constant Tf is calculated as the state amount filtering set value SP1. “Calculation unit 3-1 and state quantity filtering setting value SP 2” are set in calculation unit 3-2 and state quantity filtering setting value SP 3 ”calculation unit 3-3 (step S 108).
Tf = α | ΔSP1 ′ | (11)
The ratio α used in Equation (11) is determined by control simulation and is set in advance in the filtering time constant determination unit 10.

Next, the state quantity filtering set value SP1 ″ calculating unit 3-1 performs a first-order lag filtering process such as the following transfer function expression on the state quantity setting value SP1 to obtain the state quantity filtering set value SP1 ″. Is calculated (step S109).
SP1 ″ = SP1 / (1 + Tfs) (12)
In Expression (12), s is a Laplace operator.

The state quantity filtering set value SP2 ″ calculating unit 3-2 performs a first-order lag filtering process such as the following transfer function expression on the state quantity setting value SP2 to calculate the state quantity filtering set value SP2 ″. (Step S110).
SP2 ″ = SP2 / (1 + Tfs) (13)

The state quantity filtering setting value SP3 ″ calculating unit 3-3 performs a first-order lag filtering process such as the following transfer function expression on the state quantity setting value SP3 to calculate the state quantity filtering setting value SP3 ″. (Step S111).
SP3 ″ = SP3 / (1 + Tfs) (14)

  Subsequently, the state quantity set value conversion unit 4 performs state quantity filtering set value conversion using the state quantity conversion matrix T set in advance as in the following equation, and the reference state quantity set value SP1 ′ and the relative state The quantity set values SP2 ′ and SP3 ′ are calculated, the reference state quantity set value SP1 ′ is output to the PID control calculation unit 6-1, and the relative state quantity set values SP2 ′ and SP3 ′ are output to the PID control calculation unit 6-2. , 6-3 (step S112).

  The state quantity conversion matrix T preset in the state quantity set value conversion unit 4 is expressed by the following equation.

  The calculation of the change amount ΔSP1 ′ of the reference state quantity setting value SP1 ′ by Expression (10) is based on the reference state quantity setting value calculation part (first row) in the state quantity conversion matrix T of Expression (16). is there.

  On the other hand, the state quantity measurement value conversion unit 5 executes state quantity measurement value conversion using the state quantity conversion matrix T set in advance, as shown in the following equation, and state quantity measurement values PV1 ′, PV2 ′, PV3 ′. And the state quantity measurement values PV1 ′, PV2 ′, PV3 ′ are output to the PID control calculation units 6-1, 6-2, 6-3 (step S113).

Next, the PID control calculation unit 6-1 performs a PID control calculation like the following transfer function equation to calculate the operation amount MV1 ′ and outputs it to the operation amount conversion unit 7 (step S114).
MV1 ′ = (100 / Pb1) {1+ (1 / Ti1s) + Td1s} (SP1 ″
-PV1 ') (18)
In Expression (18), Pb1 is a proportional band, Ti1 is an integration time, and Td1 is a differentiation time.

The PID control calculation unit 6-2 performs a PID control calculation like the following transfer function equation to calculate the operation amount MV2 ′ and outputs it to the operation amount conversion unit 7 (step S115).
MV2 ′ = (100 / Pb2) {1+ (1 / Ti2s) + Td2s} (SP2 ″
-PV2 ') (19)
In Expression (19), Pb2 is a proportional band, Ti2 is an integration time, and Td2 is a differentiation time.

The PID control calculation unit 6-3 calculates a manipulated variable MV3 ′ by performing a PID control calculation like the following transfer function equation, and outputs it to the manipulated variable conversion unit 7 (step S116).
MV3 ′ = (100 / Pb3) {1+ (1 / Ti3s) + Td3s} (SP3 ″
-PV3 ') (20)
In Expression (20), Pb3 is a proportional band, Ti3 is an integration time, and Td3 is a differentiation time.

  The manipulated variable conversion unit 7 calculates manipulated variables MV1, MV2, and MV3 by using the manipulated variable conversion matrix U set in advance to calculate manipulated variables MV1, MV2, and MV3, and manipulated variables MV1, MV2, and MV3. Is output to the manipulated variable MV1 output units 8-1, 8-2, and 8-3 (step S117).

  The manipulated variable conversion matrix U preset in the manipulated variable converter 7 is expressed by the following equation.

P ^{−1 in} Expression (22) is an inverse matrix of the gain matrix P to be controlled. The gain matrix P is an n × n square matrix when the number of control loops is n, and is represented by the following equation in the present embodiment.

In Expression (23), I ₁₁ is a gain when the manipulated variable MV1 is transmitted to the state quantity measured value PV1, I ₂₁ is a gain when the manipulated variable MV2 is transmitted to the measured state quantity PV1, and I ₃₁ is a state where the manipulated variable MV3 is in the state. gain when gain when transmitted to the amount measured values PV1, I ₁₂ is the gain when the manipulated variables MV1 is transmitted to the state quantity measurement value PV2, I ₂₂ is the operation amount MV2 is transmitted to the state quantity measurement value PV2, I ₃₂ is operated Gain when the amount MV3 is transmitted to the state amount measurement value PV2, I ₁₃ is a gain when the operation amount MV1 is transmitted to the state amount measurement value PV3, I ₂₃ is a gain when the operation amount MV2 is transmitted to the state amount measurement value PV3, I ₃₃ is a gain when the manipulated variable MV3 is transmitted to the state quantity measured value PV3. The gains (transfer coefficients) I _{11 to} I ₃₃ are given by investigating interference between a plurality of loops as described in Patent Document 3.

The operation amount MV1 output unit 8-1 outputs the operation amount MV1 converted by the operation amount conversion unit 7 to the actuator A1 (step S118). The actuator A1 operates to control the first state quantity based on the operation quantity MV1.
The operation amount MV2 output unit 8-2 outputs the operation amount MV2 converted by the operation amount conversion unit 7 to the actuator A2 (step S119). The actuator A2 operates to control the second state quantity based on the operation quantity MV2.
The operation amount MV3 output unit 8-3 outputs the operation amount MV3 converted by the operation amount conversion unit 7 to the actuator A3 (step S120). The actuator A3 operates to control the third state quantity based on the operation quantity MV3.

  The processes in steps S101 to S120 as described above are repeatedly executed for each control cycle until the end of control is instructed by an operator (YES in step S121), for example.

  FIG. 4 is a diagram illustrating a simulation result of the control device of the present embodiment. FIG. 4A shows a control response when a step input of SP1 = SP2 = SP3 = 30% is added to the control device of FIG. 1, and FIG. 4B is output from the control device at the time of this step input. The manipulated variables MV1, MV2, and MV3 are shown. The simulation conditions are as follows.

First, the transfer function Gp1 of the block including the actuator A1 and the process P1, the transfer function Gp2 of the block including the actuator A2 and the process P2, and the transfer function Gp3 of the block including the actuator A3 and the process P3 are set as follows: To do. Here, it is assumed that there is no interference between control loops.
Gp1 = 0.343exp (−2.0 s)
/{(1+70.0s)(1+10.0s)} (24)
Gp2 = 0.800 exp (−2.0 s)
/{(1+60.0s)(1+10.0s)} (25)
Gp3 = 0.308exp (−2.0 s)
/{(1+50.0s)(1+10.0s)} (26)

The state quantity measurement values PV1, PV2, and PV3 are determined as follows according to the operation amounts MV1, MV2, and MV3.
PV1 = Gp1MV1 (27)
PV2 = Gp2MV2 (28)
PV3 = Gp3MV3 (29)

  The proportional band Pb1 that is the PID parameter of the PID control calculation unit 6-1 is 25.0, the integration time Ti1 is 35.0, the differential time Td1 is 20.0, and the proportionality that is the PID parameter of the PID control calculation unit 6-2 The band Pb2 is 10.0, the integration time Ti2 is 35.0, the differential time Td2 is 20.0, the proportional band Pb3, which is the PID parameter of the PID control calculation unit 6-3, is 10.0, and the integration time Ti3 is 35. 0, the differential time Td3 is 20.0. Further, the ratio α for determining the filtering time constant is set to 2.5. As a result, the filtering time constant Tf calculated by the filtering time constant determining unit 10 is about 75 seconds.

  As can be seen from FIG. 4B, according to the present embodiment, there is no situation in which the operation amounts MV1, MV2, and MV3 greatly exceed the upper limit value of 100%, and it can be understood that the operation amount saturation can be alleviated. . As a result, in the present embodiment, as shown in FIG. 4A, it is possible to avoid the effect of reducing the state quantity difference between the control loops from being lost. As shown in FIG. The measured values PV1, PV2, and PV3 can be substantially matched.

Note that the control device described in the present embodiment can be realized by a computer including an arithmetic device, a storage device, and an interface, and a program for controlling these hardware resources.
In the present embodiment, the filtering process is performed on the state quantity setting values SP1, SP2, and SP3 before being converted by the state quantity conversion matrix T. A configuration may be adopted in which filtering processing is performed on the state quantity set values SP1 ′, SP2 ′, and SP3 ′.

  In the present embodiment, the control device is configured based on the gradient temperature control method disclosed in Patent Document 3, but the control device is configured based on the cross controller method disclosed in Non-Patent Document 1. The configuration as shown in FIG. 9 may be configured in the same manner as this embodiment.

  The present invention can be applied to a process control technique.

It is a block diagram which shows the structure of the control apparatus used as embodiment of this invention. It is a block diagram of the control system in the embodiment of the present invention. It is a flowchart which shows operation | movement of the control apparatus in embodiment of this invention. It is a figure which shows the simulation result of operation | movement of the control apparatus in embodiment of this invention. It is a block diagram which shows the structure of the conventional control apparatus. It is a block diagram which shows the structure of the other conventional control apparatus. It is a block diagram which shows the structure of the conventional control apparatus which makes a control object the state quantity average value and a state quantity difference. It is a block diagram which shows the structure of the conventional control apparatus using a cross controller. It is a block diagram which shows the structure which applied the cross controller of FIG. 8 to the control apparatus of FIG. It is a block diagram which shows the structure of the conventional control apparatus using the method of inclination temperature control. It is a figure for demonstrating the problem of the conventional control apparatus.

Explanation of symbols

3-1. State quantity filtering set value SP1 "calculating section, 3-2 ... State quantity filtering setting value SP2" calculating section, 3-3 ... State quantity filtering setting value SP3 "calculating section, 4 ... State quantity setting value converting section 5 ... State quantity measurement value conversion unit, 6-1, 6-2, 6-3 ... PID control calculation unit, 7 ... Operation amount conversion unit, 9 ... Set value change amount calculation unit, 10 ... Filtering time constant determination unit .

Claims (6)

In a control device of a control system having n (n is a natural number of 2 or more) control loops,
A state quantity conversion unit that converts each state quantity measurement value of the n control loops into a value obtained by linearly combining the state quantity measurement values using an n × n state quantity conversion matrix;
A control calculation unit that calculates an operation amount of each control loop based on a control deviation between each converted state quantity measurement value and each state quantity set value corresponding thereto;
The calculated n manipulated variables are converted so as to be distributed to the manipulated variables of each control loop by an n × n manipulated variable conversion matrix, and the converted n manipulated variables are controlled by the corresponding control loop. A manipulated variable converter to output to
A control apparatus comprising: a state quantity filtering set value calculation unit that performs a filtering process for suppressing sudden fluctuations on the state quantity set value input to the control calculation unit. The control device according to claim 1,
The state quantity conversion matrix includes a reference state quantity measurement value that is an average of the state quantity measurement values of the n control loops and a state quantity measurement value of a different control loop. A relative state quantity measurement value that gives a relative relationship is included in advance,
The control device is characterized in that the manipulated variable conversion matrix is set in advance so as to eliminate or reduce the influence of the control by each control calculation unit on the control by another control calculation unit. The control device according to claim 1,
The state quantity filtering set value calculation unit performs the filtering process by time delay calculation. The control device according to claim 3,
Furthermore, the time constant of the said filtering process is provided with the correction means which corrects according to the change amount of the said state amount setting value so that the saturation of the operation amount output from the said control calculating part may be relieve | moderated. Control device. The control device according to any one of claims 1 to 4,
The operation amount conversion matrix is designed by a gradient temperature control method. The control device according to any one of claims 1 to 4,
The operation amount conversion matrix is designed by a cross controller design method.

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