JP4382632B2 - Control device - Google Patents

Description

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

  FIG. 8A 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. 8A, 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 treatment workpiece 1016 fall within the specified temperature tolerance. The
Focusing on the portion surrounded by the broken line in FIG. 8A, the state quantity for calculating the temperature difference (TC2−TC3) and the temperature change rate dTC3 / dt based on the plurality of measured temperatures TC1, TC2, and TC3. You can see that the conversion is taking place. That is, the temperature controller of FIG. 8A includes the state quantity conversion unit 1041 that calculates the temperature difference (TC2−TC3) and the temperature change rate dTC3 / dt (FIG. 8B).

  FIG. 9 (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. 9A, the detection value of the temperature sensor A converges to the target value.

When attention is paid to the portion surrounded by the broken line in FIG. 9A, 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. 9A includes the state quantity conversion unit 2008 that calculates the temperature difference (A−B) (FIG. 9B).
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, let us consider that in the two control loops, the state quantity average value PV1 'and the state quantity difference PV2' are controlled, not the state quantities PV1 and PV2 themselves. The control device in this case is shown in FIG. 10 includes a subtractor 3001 that outputs a difference between the set value SP1 ′ and the state quantity average value PV1 ′ for the state quantity average value PV1 ′, and a set value SP2 ′ and the state quantity difference for 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 simply by applying the state quantity conversion unit 3003 similar to that shown in FIGS. 8B and 9B. 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. In other words, the control device shown in FIG. 10 has a configuration in which inter-loop interference is artificially generated by the state quantity conversion unit 3003. 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. 11 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. 12 shows a configuration in which the cross controller 4005 shown in FIG. 11 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 using substantially the same method as the control device shown in FIG. 11, there is a control device using 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. 13 includes a temperature regulator 5001 that controls the temperature of the process to be controlled 5002. The temperature regulator 5001 is a 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 apparatus shown in FIGS. 12 and 13, 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”. In the ranges disclosed in Non-Patent Document 1 and Patent Document 3, the reference state quantity is a simple average value of the state quantities of each control loop, or simply a specific one state quantity. These can be said to be weighted average values with a fixed weight if viewed by broad broad concepts. When each state quantity can be controlled without restriction, it is effective to use a weighted average value with a fixed weight as the reference state quantity. In particular, the simple average value is a well-balanced and fair reference state quantity. For example, in the case of two loops, PV1 '= 0.5PV1 + 0.5PV2.

  However, if control restrictions such as manipulated variable saturation occur in a virtually unexpected manner, the fixed weight may adversely affect. Hereinafter, problems of the control apparatus shown in FIGS. 12 and 13 will be described with reference to FIGS. 14 (a) and 14 (b). Here, there are three temperature control loops I, II, and III, and the purpose of the control is to reduce the temperature difference (relative state quantity) between the control loops. That is, the temperatures (state quantities) PV1, PV2, and PV3 are measured in the control loops I, II, and III, and the reference state quantity measured value PV1 ′ = (PV1 + PV2 + PV3) by the state quantity conversion unit 3003 or the average temperature / gradient temperature calculation means 5003. ) / 3 and relative state quantity measurement value PV2 ′ = PV2-PV1 and relative state quantity measurement value PV3 ′ = PV3-PV2. Based on PV1 ′, PV2 ′, and PV3 ′, the operation amounts MV1 ′, MV2 ′, and MV3 ′ are calculated by the controllers of the control loops I, II, and III, and the operation amounts MV1 ′, MV2 ′, and MV3 ′ are calculated. It is converted into operation amounts MV1, MV2, and MV3 by the cross controller 4005 or the distribution means 5006 and output to the process to be controlled.

  FIG. 14A shows the disturbance response of the control system when a disturbance is applied in a state where the state quantity set values SP of the control loops I, II, and III are all set to 30. FIG. Indicates the manipulated variables MV1 ′, MV2 ′, and MV3 ′ output from the controllers of the control loops I, II, and III when a disturbance is applied. The output upper limit value of the manipulated variable MV3 'of the controller of loop III was experimentally set to 16% to facilitate output saturation. For this reason, when the reference state quantity is a simple average value of the temperatures of the control loops I, II, and III, it is assumed that the manipulated variable MV3 'of the loop III is saturated in the middle of the disturbance response and the temperature rising rate reaches a peak. Then, only the temperature of the loop III becomes insufficient, and the temperature PV3 of the loop III is separated from the temperatures PV1 and PV2 of the loops I and II as shown in FIG. Since the reference state quantity is a simple average value of the temperatures PV1, PV2, and PV3 of the loops I, II, and III, if a deviation occurs between the temperature PV3 of the loop III and the temperatures PV1 and PV2 of the loops I and II, The value closer to the temperatures PV1 and PV2 of the loops I and II than the temperature PV3 is the reference state measurement value PV1 ′. Therefore, the controller of each loop I, II, III does not attempt to reduce the temperature difference by bringing the temperatures PV1, PV2, PV3 of the loops I, II close to the temperature PV3 of the loop III, but the temperature PV3 of the loop III. Is made closer to the temperatures PV1 and PV2 of the loops I and II to reduce the temperature difference.

  However, as described above, the manipulated variable MV3 ′ of the loop III is already saturated and the rate of temperature rise has reached its peak, so that the temperature PV3 of the loop III quickly approaches the temperatures PV1 and PV2 of the loops I and II. There is no effect. Therefore, the effect that the reference state quantity can be controlled simultaneously while controlling the temperature difference cannot be obtained. As described above, the control devices shown in FIGS. 12 and 13 have a problem that the original effect of reducing the state quantity difference is greatly impaired depending on control restrictions.

  The present invention has been made in order to solve the above-described problem. When a control system having at least two control loops is controlled so as to reduce the state quantity difference, control restrictions such as manipulated variable saturation are imposed. It is an object of the present invention to provide a control device that does not impair the effect of reducing the state quantity difference, which is the original purpose, even if it occurs in an unexpected manner.

The present invention provides a control system controller having n (n is a natural number of 2 or more) parallel PID control loops, a weighted average value of the state quantities of the n PID control loops, and a specific reference The reference state which is a weighted average of the measured values of the respective state quantities of the n PID control loops, where the absolute state quantity is a reference state quantity and the relative state quantity which is a state quantity difference is a relative state quantity. Each state quantity measurement value of the n PID control loops is included so that a quantity measurement value and a relative state quantity measurement value that gives a relative relationship between the state quantity measurement values of different PID control loops are included after conversion. a state quantity conversion unit that performs linear combination by an n × n state quantity conversion matrix to convert the reference state quantity measurement value and the relative state quantity measurement value , the converted state quantity measurement values, and the corresponding state quantity measurement values The manipulated variable is based on the control deviation from the state quantity set value. The n PID control arithmetic units to be output and the calculated n operation amounts are made non-interfering so that the influence of the control by each PID control arithmetic unit on the control by other PID control arithmetic units is eliminated or reduced. As described above, an operation amount conversion unit that converts an n × n operation amount conversion matrix so as to be distributed to each PID control loop and outputs the converted n operation amounts to control targets of the corresponding PID control loops, A control deviation calculation unit for calculating a control deviation between each state quantity measurement value of each of the n PID control loops and each state quantity set value corresponding thereto, and each of the calculated controls A maximum deviation control system search unit that compares absolute values of deviations and searches for a PID control loop having the largest absolute value of control deviation, and a PID control loop having a larger absolute value of the calculated control deviation, By significantly modify the heavy, those comprising a matrix correction unit for correcting the state quantity conversion matrix and the operation amount conversion matrix corresponding thereto.

Further, in one configuration example of the control device of the present invention, the manipulated variable conversion matrix is converted by the manipulated variable of the n PID control loops and the state variable converter by being designed by a gradient temperature control method. In addition, a product with a matrix that gives a relationship with each state quantity measurement value is set as an inverse matrix that becomes a unit matrix .
Further, in one configuration example of the control device of the present invention, the operation amount conversion matrix is converted by the operation amount of the n PID control loops and the state amount conversion unit by being designed by a cross controller design method. In addition, the product of the matrix and the matrix giving the relationship with each state quantity measurement value is set as a diagonal matrix .

  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 state between a plurality of state quantities is provided by providing an operation amount conversion unit that converts the n manipulated variables to be distributed to each control loop by a matrix and outputs the converted n manipulated variables to the control target of the corresponding control loop. Control that changes the reference state quantity to a desired value while maintaining a relative state quantity such as a quantity difference at a desired value can be realized. Furthermore, in the present invention, by providing a matrix correction unit that adaptively corrects the state quantity conversion matrix and the operation quantity conversion matrix, when controlling the relative state quantity to be small, Even when the restriction is generated in an unexpected manner, it is possible to avoid losing the effect of reducing the state quantity difference, which is the original purpose.

  Further, in the present invention, when there is a disturbance in the control of the relative state quantity measurement value due to control system constraints, the control calculation unit of the control loop that is not restricted than the control calculation unit of the control loop that is restricted is Control constraints can be virtually anticipated by adaptively modifying the state variable transformation matrix and the corresponding manipulated variable transformation matrix so that control that corrects the disturbance of the relative state variable measurement value is more strongly required. Even if it occurs in a non-circular shape, it can be avoided that the effect of reducing the state quantity difference is impaired.

[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, it is noted that there is a cause of the problem of the control device shown in FIGS. 12 and 13 where the reference state quantity is a weighted average value of fixed weights of the state quantities of each control loop. That is, the above-described problem is that, for example, when the temperature of loop III deviates from the temperatures of loops I and II due to operation amount saturation or the like, the reference state quantity measurement value to be aimed at by each control loop is larger than the loop III temperature. This is due to the fact that the controller of Loop III, which is originally restricted, is more strongly required to control the state quantity difference in order to become the value closer to the temperature of I and II.

  The present invention adaptively corrects the weighted average weight when there is a control loop that is a factor that disturbs the control of the state quantity difference due to some restrictions based on the above point of view. The above-mentioned problem is solved by making it possible to more strongly request the control of the state quantity difference to the controller of the non-control loop. Specifically, the weighted average weight is adaptively corrected so that the reference state quantity measurement value approaches the state quantity measurement value of the control loop which is the most disturbing factor of the state quantity difference control.

  In the present invention, it is assumed that control is performed so that the state quantity difference of each loop becomes small in n control loops. It is not always possible to reliably grasp a control loop in which control restrictions such as operation amount saturation occur in an unexpected manner. However, if such a constraint is a factor that disturbs the control of the state quantity difference, the response of the control loop receiving the constraint is delayed and the follow-up to other loops is insufficient. The situation is most likely. Therefore, it is only necessary to adaptively correct the weighted average weight so that other control loops are matched with the control loops with delayed responses.

  Specifically, the weight for the state quantity of the loop having the largest absolute value of the control deviation Eri0 between the state quantity set value SPi and the state quantity measurement value PVi is 1, and the weight for the state quantity of the other control loop is 0. Thus, the weighted average weight of the state quantity is adaptively corrected. In this case, since the control operation tends to be discontinuous when the weight changes suddenly, it is preferable to apply a time delay filter to the weight correction process so that the weight gradually changes. For example, if no overshoot occurs in the response waveform of each control loop, even if the weight for the state quantity of the loop having the largest deviation is suddenly changed to 1, an extreme discontinuity occurs in the control response The probability of doing is low. However, when the overshoot occurs in the response waveform, if the weight for the state quantity of the loop having the largest absolute value is suddenly changed to 1, the loop having the largest absolute value of the deviation becomes the upper side of the state quantity set value SPi. Since a situation can occur that suddenly changes between the lower side and the lower side, an extreme discontinuity occurs.

  The method of adaptively correcting the weight is not limited to a method in which the weight for the state quantity of the loop having the largest absolute value of the deviation is set to 1. For example, the weight for the state quantity of the loop having the largest absolute value of the deviation is set to 0. As shown in FIG. 8, if the remaining weight of 0.2 is equally divided as the weight of the state quantity of other loops, the weight is increased as the loop with a larger absolute value of the deviation becomes effective. Is obtained.

  When the conversion matrix of the state quantity conversion unit (average temperature / gradient temperature calculation unit 5003) is adaptively corrected, the inverse matrix of the operation amount conversion unit (cross controller 4005 or distribution unit 5006) is also corrected accordingly. Therefore, by performing inverse matrix calculation as necessary, or by preparing a plurality of pairs of transformation matrix and inverse matrix in advance and appropriately selecting the pair corresponding to the loop with the largest absolute value of control deviation Thus, substantial adaptive correction will be realized.

[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 calculates a state quantity set value SP1 input unit 1-1, a state quantity measurement value PV1 input unit 2-1, and a control deviation Er10 as the configuration of the first measurement system related to the first state quantity. Unit 3-1 and the configuration of the second measurement system related 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 control deviation Er20. A calculation unit 3-2, and the configuration of the third measurement system relating to the third state quantity includes a state quantity set value SP3 input unit 1-3, a state quantity measurement value PV3 input unit 2-3, and a control deviation. An Er30 calculator 3-3.

  1 has a state quantity conversion matrix T storage unit 4 that stores a state quantity conversion matrix T for executing state quantity conversion, and a state quantity conversion matrix T as a configuration related to state quantity conversion. A state quantity set value conversion unit 5 that executes the conversion of the set values and a state quantity measurement value conversion unit 6 that executes the conversion of the state quantity measurement values using the state quantity conversion matrix T are provided.

  In addition, the control device of FIG. 1 includes a PID control calculation unit (PID controller) 7-1 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 7-2 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 7-3, an operation amount conversion matrix U storage unit 8 for storing an operation amount conversion matrix U for executing an operation amount conversion, and an operation amount conversion for performing operation amount conversion by the operation amount conversion matrix U Unit 9, an operation amount MV1 output unit 10-1, an operation amount MV2 output unit 10-2, and an operation amount MV3 output unit 10-3.

Further, the control device of FIG. 1 has a configuration relating to weighted adaptive correction, and compares the absolute values of the control deviations of the respective control systems and searches for a control system having the largest absolute value of the control deviations, A matrix for storing the state quantity conversion matrix T and the manipulated variable conversion matrix U in the state quantity conversion matrix T storage unit 4 and the manipulated variable conversion matrix U storage unit 8 so that the weight on the state quantity of the maximum deviation control system is maximized. And a correction unit 12. Note that the state quantity conversion matrix T is an n × n square matrix when the number of control loops is n, and an inverse matrix T ⁻¹ needs to exist.

  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, control deviation Er10 calculation section 3-1, state quantity set value conversion section 5, and state quantity measurement value conversion section 6 The PID control operation units 7-1, 7-2 and 7-3, the operation amount conversion unit 9, the operation amount MV1 output unit 10-1, the actuator A 1, and the process P 1 are the first control system. (First control loop) is configured. State quantity set value SP2 input section 1-2, state quantity measurement value PV2 input section 2-2, control deviation Er20 calculation section 3-2, state quantity set value conversion section 5, and state quantity measurement value conversion section 6 The PID control operation units 7-1, 7-2, 7-3, the operation amount conversion unit 9, the operation amount MV2 output unit 10-2, the actuator A 2, and the process P 2 are the second control system. (Second control loop) is configured. Then, the state quantity set value SP3 input unit 1-3, the state quantity measurement value PV3 input unit 2-3, the control deviation Er30 calculation unit 3-3, the state quantity set value conversion unit 5, and the state quantity measurement value conversion Unit 6, PID control operation units 7-1, 7-2, 7-3, manipulated variable converter 9, manipulated variable MV3 output unit 10-3, actuator A 3, and process P 3 are the third A 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 is sent to the control deviation Er10 calculation unit 3-1 and the state quantity measurement value conversion unit 6 via the state quantity measurement value PV1 input unit 2-1. Input (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 control deviation Er20 calculation unit 3-2 and the state quantity measurement value conversion unit 6 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 control deviation Er30 calculation unit 3-3 and the state quantity measurement value conversion unit 6 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 control deviation Er10 calculation unit 3-1 and the state quantity set value conversion unit 5 via the state quantity set value SP1 input unit 1-1 (Step S1). S104). The state quantity set value SP2 is set by the operator, and is input to the control deviation Er20 calculation unit 3-2 and the state quantity set value conversion unit 5 via the state quantity set value SP2 input unit 1-2 (step S105). The state quantity set value SP3 is set by the operator, and is input to the control deviation Er30 calculation unit 3-3 and the state quantity set value conversion unit 5 via the state quantity set value SP3 input unit 1-3 (step S106).

Subsequently, the control deviation Er10 calculation unit 3-1 calculates the control deviation Er10 between the state quantity set value SP1 and the state quantity measurement value PV1 as shown in the following equation and outputs the control deviation Er10 to the maximum deviation control system search unit 11 (step S1). S107).
Er10 = SP1-PV1 (10)

The control deviation Er20 calculation unit 3-2 calculates the control deviation Er20 between the state quantity set value SP2 and the state quantity measurement value PV2 as shown in the following equation, and outputs it to the maximum deviation control system search unit 11 (step S108).
Er20 = SP2-PV2 (11)

The control deviation Er30 calculation unit 3-3 calculates the control deviation Er30 between the state quantity set value SP3 and the state quantity measurement value PV3 as shown in the following equation and outputs it to the maximum deviation control system search unit 11 (step S109).
Er30 = SP3-PV3 (12)

  Next, the maximum deviation control system search unit 11 obtains absolute values | Er10 |, | Er20 |, | Er30 | of the control deviations Er10, Er20, Er30, and based on the absolute values of the control deviations of the respective control systems, A control system j having the largest absolute value of the control deviation (hereinafter referred to as the maximum deviation control system j) is specified (step S110).

The matrix correction unit 12 selects the state quantity conversion matrix T such that the weight for the state quantity of the maximum deviation control system j is 1 and the weight for the state quantity of the other control system is 0, and the selected state quantity conversion is performed. The matrix T is set in the state quantity conversion matrix T storage unit 4 (step S111).
When the first control system is the maximum deviation control system j, the matrix correction unit 12 selects a state quantity conversion matrix T as shown in Expression (13).

  When the state quantity set value and the state quantity measurement value, which will be described later, are converted, the state quantity set value SP1 ′ is equal to the state quantity set value SP1 using the state quantity conversion matrix T of Expression (13). The state quantity measurement value PV1 ′ is equal to the state quantity measurement value PV1. When the weighted average value of the state quantities of the three control loops is set as the reference state quantity, the weight for the state quantity of the first control system is set to 1, and the weight for the state quantities of the other control systems is set to 0. This is equivalent to

  When the second control system is the maximum deviation control system j, the matrix correction unit 12 selects a state quantity conversion matrix T as shown in Expression (14).

  When the third control system is the maximum deviation control system j, the matrix correction unit 12 selects a state quantity conversion matrix T as shown in a predetermined equation (15).

  When the two control systems simultaneously become the maximum deviation control system j, for example, when the first control system and the second control system become the maximum deviation control system j, among the expressions (13) and (14) Any one of them may be selected, and when three control systems become the maximum deviation control system j at the same time, select one of the equations (13), (14), and (15). That's fine.

  It should be noted that the state quantity conversion matrix T in the equations (13) to (15) plays a role of correcting the relative state quantity as well as correcting the weight. That is, the state quantity conversion matrix T is set in advance so that the difference between the state quantity of the maximum deviation control system j and the state quantity of the other control system becomes a relative state quantity. For example, when the state quantity set value and the state quantity measurement value are converted, if the state quantity conversion matrix T of Expression (13) is used, the relative state quantity set value SP2 ′ becomes SP1-SP2, and the relative state quantity setting is performed. The value SP3 ′ is SP1-SP3, the state quantity measurement value PV2 ′ is PV1-PV2, and the state quantity measurement value PV3 ′ is PV1-PV3. The reason for correcting the relative state quantity according to the maximum deviation control system j is that the relative state quantity can be controlled better if the relative state quantity is determined based on the state quantity of the maximum deviation control system j.

Further, the matrix correction unit 12 is an operation designed to correspond to the state quantity conversion matrix T in which the weight for the state quantity of the maximum deviation control system j is 1 and the weight for the state quantity of the other control system is 0. The amount conversion matrix U is selected, and the selected operation amount conversion matrix U is set in the operation amount conversion matrix U storage unit 8 (step S112).
When the first control system is the maximum deviation control system j, the matrix correction unit 12 selects a manipulated variable conversion matrix U as shown in Expression (16).

  When the second control system is the maximum deviation control system j, the matrix correction unit 12 selects a manipulated variable conversion matrix U as shown in Expression (17).

  When the third control system is the maximum deviation control system j, the matrix correction unit 12 selects a manipulated variable conversion matrix U as shown in Expression (18).

Note that P ⁻¹ in Expressions (16) to (18) is an inverse matrix of the gain matrix P to be controlled, and is stored in advance in the matrix correction unit 12. 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 (19), 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 state quantity measured value 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.

  Next, the state quantity set value conversion unit 5 performs the state quantity set value conversion using the state quantity conversion matrix T set in the state quantity conversion matrix T storage unit 4 as in the following equation, and the reference state quantity The set value SP1 ′ and the relative state quantity set values SP2 ′ and SP3 ′ are calculated, the reference state quantity set value SP1 ′ is output to the PID control calculation unit 7-1, and the relative state quantity set values SP2 ′ and SP3 ′ are calculated. The data is output to the PID control calculation units 7-2 and 7-3 (step S113).

  On the other hand, the state quantity measurement value conversion unit 6 executes state quantity measurement value conversion using the state quantity conversion matrix T set in the state quantity conversion matrix T storage unit 4 as in the following equation, and the state quantity measurement value PV1 ′, PV2 ′, and PV3 ′ are calculated, and the state quantity measurement values PV1 ′, PV2 ′, and PV3 ′ are output to the PID control calculation units 7-1, 7-2, and 7-3 (step S114).

Next, the PID control calculation unit 7-1 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 9 (step S115).
MV1 ′ = (100 / Pb1) {1+ (1 / Ti1s) + Td1s} (SP1 ′
-PV1 ') (22)
In Expression (22), Pb1 is a proportional band, Ti1 is an integration time, Td1 is a differentiation time, and s is a Laplace operator.

The PID control calculation unit 7-2 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 9 (step S116).
MV2 ′ = (100 / Pb2) {1+ (1 / Ti2s) + Td2s} (SP2 ′
-PV2 ') (23)
In Expression (23), Pb2 is a proportional band, Ti2 is an integration time, and Td2 is a differentiation time.

The PID control calculation unit 7-3 performs a PID control calculation such as the following transfer function equation to calculate the operation amount MV3 ′ and outputs it to the operation amount conversion unit 9 (step S117).
MV3 ′ = (100 / Pb3) {1+ (1 / Ti3s) + Td3s} (SP3 ′
−PV3 ′) (24)
In Expression (24), Pb3 is a proportional band, Ti3 is an integration time, and Td3 is a differentiation time.

  The manipulated variable conversion unit 9 performs the manipulated variable conversion using the manipulated variable conversion matrix U set in the manipulated variable conversion matrix U storage unit 8 to calculate the manipulated variables MV1, MV2, and MV3. The operation amounts MV1, MV2, and MV3 are output to the operation amount MV1 output units 10-1, 10-2, and 10-3 (step S118).

The operation amount MV1 output unit 10-1 outputs the operation amount MV1 converted by the operation amount conversion unit 9 to the actuator A1 (step S119). The actuator A1 operates to control the first state quantity based on the operation quantity MV1.
The operation amount MV2 output unit 10-2 outputs the operation amount MV2 converted by the operation amount conversion unit 9 to the actuator A2 (step S120). The actuator A2 operates to control the second state quantity based on the operation quantity MV2.
The operation amount MV3 output unit 10-3 outputs the operation amount MV3 converted by the operation amount conversion unit 9 to the actuator A3 (step S121). The actuator A3 operates to control the third state quantity based on the operation quantity MV3.

  The processes in steps S101 to S121 as described above are repeatedly executed for each control cycle until the end of control is instructed by an operator (YES in step S122), for example.

  FIG. 4 is a diagram illustrating a simulation result of a control device that does not apply the cross controller or the gradient temperature control method. 5 and 6 are diagrams illustrating simulation results of a control device to which the gradient temperature control method of Patent Document 3 is applied. FIG. 7 is a diagram illustrating a simulation result of the control device according to the present embodiment. 4 to 7 show the disturbance response of the control system when a disturbance is applied in a state where SP1 = SP2 = SP3 = 30. 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 = 1.2exp (−2.0 s) / {(1 + 70.0 s) (1 + 10.0 s)}
... (26)
Gp2 = 1.6exp (−2.0s) / {(1 + 60.0s) (1 + 10.0s)}
... (27)
Gp3 = 2.0exp (−2.0s) / {(1 + 50.0s) (1 + 10.0s)}
... (28)

The lower limit of the operation amount of the actuator A1 is 0%, the upper limit is 100%, the lower limit of the operation amount of the actuator A2 is 0%, the upper limit is 100%, the lower limit of the operation amount of the actuator A3 is 0%, and the upper limit is 16%. The state quantity measurement values PV1, PV2, and PV3 are determined as follows according to the operation amounts MV1, MV2, and MV3.
PV1 = Gp1MV1 (29)
PV2 = Gp2MV2 (30)
PV3 = Gp3MV3 (31)

  The proportional band Pb of the first PID control calculation unit (corresponding to the PID control calculation unit 7-1) of the control device used in the simulation of FIG. 4 is 50.0, the integration time Ti is 35.0, and the differential time Td is 20 0.0, the proportional band Pb of the second PID control calculation unit (corresponding to the PID control calculation unit 7-2) is 66.7, the integration time Ti is 35.0, the differential time Td is 20.0, The proportional band Pb of the PID control calculation unit (corresponding to the PID control calculation unit 7-3) is 100.0, the integration time Ti is 35.0, and the differentiation time Td is 20.0. Further, the proportional band Pb1 of the PID control calculation unit 7-1 of the control device used in the simulations of FIGS. 5 to 7 is set to 100.0, the integration time Ti1 is set to 35.0, and the differential time Td1 is set to 20.0 to perform PID control. The proportional band Pb2 of the calculation unit 7-2 is 40.0, the integration time Ti2 is 35.0, the differential time Td2 is 20.0, the proportional band Pb3 of the PID control calculation unit 7-3 is 40.0, and the integration time Ti3 Is 35.0 and the derivative time Td3 is 20.0.

The simulation results shown in FIG. 4 are obtained by control without applying a cross controller or a gradient temperature control method. Since the relative state quantity (state quantity difference) is not controlled, the state quantity measurement values PV1, PV2, and PV3 are not aligned.
The simulation result shown in FIG. 5 is obtained by applying the gradient temperature control method and fixing the reference state quantity to a simple average of the state quantities of each control loop. Compared with the result of FIG. 4, the effect of the control device that the state quantity difference between the control loops is reduced appears. However, because the upper limit value of the operation amount of the actuator A3 is 16%, MV3 is saturated before the operation amounts MV1 and MV2, and PV3 cannot follow the state amount measurement values PV1 and PV2, and the state amount The effect of reducing the difference is greatly impaired.

  The simulation result shown in FIG. 6 is based on the control using the gradient temperature control technique, but the state variable conversion matrix T and the manipulated variable conversion matrix U are previously set, and the third control system is the maximum deviation control system j. It is obtained by fixing to the case matrix. For this reason, the state quantity measurement values PV1 and PV2 follow PV3, and the effect of reducing the state quantity difference between the control loops is not impaired. As a result, it is possible to verify that the state quantity measurement values PV1, PV2, and PV3 are aligned to the level shown in FIG. 6 when the simulation conditions are controlled without any loss of the effect of reducing the state quantity difference.

  The simulation result shown in FIG. 7 is obtained by the control of the present embodiment, and the control result substantially the same as that of FIG. 6 is obtained, and the effect of reducing the state quantity difference is completely impaired. It can be verified that it is not.

Note that the control device described in this embodiment can be realized by a computer including an arithmetic device, a storage device, and an interface, and a program that controls these hardware resources.
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. Also in the case of the configuration as shown in FIG. 12, the matrix representing the input / output relationship between the state quantity conversion unit and the operation amount conversion unit (cross controller) may be modified adaptively.

  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 which does not apply the method of a cross controller or inclination temperature control. It is a figure which shows the simulation result of operation | movement of the control apparatus to which the method of inclination temperature control is applied. It is a figure which shows the simulation result of operation | movement of the control apparatus to which the method of inclination temperature control is applied. 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. 11 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, control deviation Er10 calculation unit, 3-2 ... control deviation Er20 calculation unit, 3-3 ... control deviation Er30 calculation unit, 4 ... state quantity conversion matrix T storage unit, 5 ... state quantity set value conversion unit, 6 ... state quantity measurement value conversion unit, 7-1, 7-2, 7-3 ... PID control calculation unit, 8 ... manipulated variable conversion matrix U storage unit, 9 ... manipulated variable conversion unit, 11 ... maximum deviation control system search unit 12 ... Matrix correction unit.

Claims (3)

In a control system controller having n (n is a natural number of 2 or more) parallel PID control loops,
When a weighted average value of the state quantities of the n PID control loops and a specific reference absolute state quantity is a reference state quantity, and a relative state quantity that is a state quantity difference is a relative state quantity ,
A reference state quantity measurement value that is a weighted average of each state quantity measurement value of the n PID control loops and a relative state quantity measurement value that gives a relative relationship between the state quantity measurement values of different PID control loops are converted. A state in which each state quantity measurement value of the n PID control loops is linearly combined by an n × n state quantity conversion matrix to be converted into the reference state quantity measurement value and the relative state quantity measurement value , as included later A quantity conversion unit;
N PID control calculation units for calculating an operation amount based on a control deviation between each converted state quantity measurement value and each corresponding state quantity set value;
The n × n manipulated variable conversion matrix is used to eliminate or reduce the influence of the control by each PID control computation unit on the control by other PID control computation units as non-interference. An operation amount converter that converts the n operation amounts to be output to the control target of the corresponding PID control loop,
A control deviation calculation unit for calculating a control deviation between each state quantity measurement value of the n PID control loops and each state quantity set value corresponding thereto, for each state quantity measurement value;
A maximum deviation control system search unit that compares the calculated absolute values of the control deviations and searches for a PID control loop having the largest absolute value of the control deviation;
A PID control loop having a larger absolute value of the calculated control deviation, by correcting the weight of the weighted average value to a greater extent, thereby correcting the state quantity conversion matrix and the corresponding operation quantity conversion matrix; A control device comprising: The control device according to claim 1,
The manipulated variable conversion matrix is a matrix that provides a relationship between the manipulated variable of the n PID control loops and the measured value of each state variable converted by the state variable converter by being designed by the gradient temperature control method. Is set as an inverse matrix that becomes a unit matrix . The control device according to claim 1,
The manipulated variable conversion matrix is a matrix that is designed by a cross controller design method to give a relationship between the manipulated variable of the n PID control loops and the measured value of each state quantity converted by the state quantity converter. A control device characterized in that the product of is set as a matrix that becomes a diagonal matrix .

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