JP2004348481A - Process control unit and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform appropriate control even if a turbulence pattern applied to a process is not constant and the dead time of the process is long, in a process control unit where a main controller and a sub controller are connected in cascade. <P>SOLUTION: A turbulence estimator, including a controller for performing model control and a pseudo control target that is the same transfer function as that of a control target including the sub controller and the process and is expressed as a transfer function without any dead time, is used. Then, when the process is performed, the amount of control of the process, for example the detection value of temperature (inner temperature) in a reaction container, is used as a target value, the output (the inner temperature when no turbulence is included) of the pseudo control target is inputted to the controller of the turbulence estimator, the difference between the amount of operation of the controller and that of the main controller is taken out as an estimated turbulence for storage. Then, in the next operation cycle, the estimated turbulence is converted to the amount of feed forward operation, and the amount of feed forward operation is added to the amount of operation of the main controller to compensate the turbulence. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００３６】
一般的なバッチプロセスにおける工程進行に伴い生ずる外乱の多くは、発熱、吸熱による反応熱の寄与分が高いと見なされるため、ＤＶ_１＞＞ＤＶ_２となる。また実際の内温Ｙ_Ｐおよび擬似制御対象である演算処理部５２の演算結果（制御結果）である内温Ｙ_Ｐ’は次のように定式化される。
【００３７】
【数２】

【００３８】
【数３】

【００３９】
Ｇ_Ｐ≒Ｇ_Ｐ’と見なされる場合には、Ｙ_ｐとＹ_ｐの比は次式となる。
【００４０】
【数４】

【００４１】
一方、推定用調節器はジャケットタンク１の内温、すなわちＹ_ｐを設定値とし、従調節器３２と既述のプロセスからなる制御対象の熱移動を一次遅れモデルに近似した伝達関数Ｇ_Ｐ’を制御する。ここで、設定値Ｙ_Ｐの変化に対して、制御量Ｙ_Ｐ’は、推定用調節器５１にて設定される参照軌道に依存するが、Ｙ_Ｐの変化に少し遅れて追従するので次式となる。
【００４２】
【数５】

【００４３】
従調節器３２とプロセスとに相当する擬似制御系である演算処理部５２においては、熱移動を一次遅れモデルに近似した伝達関数Ｇ_Ｐ’は無駄時間を含まない制御系を構成していることから、推定用調節器５１はＹ_Ｐ’の応答時間を無限に早く設定することが可能となる。推定用調節器５１の希望応答時間を十分に小さくすると次式となる。
【００４４】
【数６】

【００４５】
従って、式（数４）と式（数５）の関係より次式が得られる。
【００４６】
【数７】

【００４７】
【数８】

【００４８】
よって、主調節器３１の操作量と推定用調節器５１の操作量との差から推定外乱ＤＶ’が導かれた。この推定外乱ＤＶ’は既述のように外乱補償のフィードフォワード操作量に利用される。
【００４９】
ただし推定外乱ＤＶ’は反応容器１１の温度から求めているため、反応容器１１の無駄時間θを考慮すると、反応容器１１の前に加わるＤＶは次式で与えられる。
【００５０】
【数９】

【００５１】
フィードフォワード操作量への変換は推定外乱ＤＶ’を打ち消すように主調節器３１の操作量に加えればよいので、外乱補償量Ｄ_Ｆは次式となる。
【００５２】
【数１０】

【００５３】
すなわち推定外乱ＤＶ’の符号を換えたものにプロセスの無駄時間分の位相を進めて、主調節器３１の操作量に加えれば、加わった外乱ＤＶ’は打ち消され、外乱補償が容易に実現できる。ただし、外乱推定を行った同一レシピの次回バッチ運転時以降に推定外乱パターンに基づいた外乱補償が実現される。
【００５４】
式（数８）は従調節器３２の前段に外乱が加わったと仮定した結果より導出されたので、実際に観測できる内温の温度ＤＶ_ｔｅｍｐに変換するにはＤＶ’に伝達関数Ｇ_Ｐ’を乗ずればよい。
【００５５】
【数１１】

【００５６】
推定外乱発生器４６はプロセスの無駄時間分の位相を早め、主調節器３１の制御周期に合わせて推定外乱値を逐次出力する。ＦＦ演算器４７は、ＤＶ’を入力とし、式（数１０）により外乱補償操作量Ｄ_Ｆを演算し、主調節器３１の操作出力に加算される。同一レシピにおいては、ＤＶ’・ｅ^θｓ≒−Ｄ_Ｆとなるため外乱補償が容易に実現できる。一方、外乱補償を制御に取り込んだ場合、設定値からの偏差は式（数１）の右辺第二項、第三項によるものが主となる。
【００５７】
次に、上述の実施の形態に係るプロセス制御装置を計算機を用いて実施する場合における処理の全体の流れについて図７のフローチャートを参照しながら説明する。同図において、プロセス制御装置が起動すると、表示／操作部４３は操作員からの入力操作待ち、あるいは通信プログラムによる遠隔装置への操作員による入力操作待ちとなる（ステップＳ１）。入力操作により製品の製造実施が選択されると、表示画面にて（図６参照）、製造する製品の情報についてレシピの確認および、外乱補償データを指定する（ステップＳ２）。運転はレシピ情報に基づきバッチプロセスが進行するが、この例ではＤＣＳ等他の計算機により運転シーケンス処理の機能を有するものとしている。外乱補償データとして、過去に得られたどの推定外乱パターンを使用するかを選択し、トリガータグの設定、位相、補償時間を設定する。使用する推定パターンについては、この例では外乱補償器４の中の推定外乱パターン記憶部４２から運転開始以前に前もって外乱処理部４４を介して出力外乱パターン記憶部４５に転送される。
【００５８】
次いで、データ収集を行うか否かが判断され（ステップＳ３）、「データ収集」が選択されていれば、これから行われる運転時において無条件に運転データを運転来歴記憶部４８に記憶し、外乱推定部４１で推定された外乱は推定外乱パターン記憶部４２に記憶されることとなる（ステップＳ４）。これら運転記憶時間は表示／操作部４３により任意に設定でき、全運転時間の情報を記憶もしくは一部のみ記憶できる。そしてジャケットタンク１内に原料が投入され、運転開始とともに、制御器３によりジャケットタンク１の制御が開始されて製品の製造が行われるが（ステップＳ４）、トリガータグと位相で決められた時間（以下、外乱補償開始時間）に達するまでは制御器３は通常のモデル予測制御（ＭＰＣ制御）として動作しており、外乱補償ＭＰＣ制御は動作しない。外乱補償開始時間に達した時点より、推定外乱発生器４６から制御周期毎に推定外乱値が出力され、ＦＦ演算器４７にてフィードフォワード操作量に変化された後、制御器３の主調節器３１の出力側の加算器３３に出力される。
【００５９】
この結果主調節器３１にて内温（検出値）と内温の目標値とから演算される操作量と、ＦＦ演算器４７からのフィードフォワード操作量と、を加算して従調節器３２に出力し、こうして外乱補償が行われる（ステップＳ４）。外乱補償対象時間が終了するまで、制御周期毎に推定外乱値の出力、フィードフォワード操作量への変化、この操作量と主調節器３１からの操作量との加算処理を繰り返す。そしてデータ収集が設定されているので、運転時に収集した運転来歴データ及び推定外乱パターンが運転終了後に夫々運転来歴記憶部４８及び推定外乱パターン記憶部４２に登録（記憶の確定）がされる（ステップＳ５）。またステップＳ３にてデータ収集が選択されない場合には、製品製造だけが行われ（ステップＳ６）、外乱補償、外乱推定データの収集及び運転来歴データの収集は行われない。
【００６０】
ところで外乱補償を行うことにより理屈の上では外乱が発生しないはずであるが、実際には外乱推定部４１により外乱を推定すると外乱パターンが得られることがある。この外乱パターンは例えば原料の性状などの微妙な差異により、外乱補償を行っている場合になおも発生する外乱であるから、例えば第１回目のバッチ処理（運転サイクル）時に推定した外乱を用いて外乱の補償を行いながら２回目のバッチ処理を行い、このときに得られた推定外乱パターンと１回目に得られた推定外乱パターンとを加算して３回目のバッチ処理を行うようにしてもよい。
【００６１】
一方ステップＳ１にて操作員が製品製造を選択せず、ステップＳ７にてオフライン外乱推定を選択した場合には、例えば選択された過去の運転サイクルにおける運転来歴データである制御量に相当する内温（検出値）及び主調節器３１の操作量に基づいて外乱推定部４１により外乱パターンが推定され（ステップＳ８）、推定外乱パターン記憶部４２に登録される（ステップＳ５）。
【００６２】
以上述べた実施の形態によれば、過去の運転により得られた推定外乱パターンを用い、次回以降の運転においてフィードフォワード操作量に変換して主調節器３１からの操作量に対して外乱を打ち消すように補償値として加えているので、プロセスに加わる外乱を排除またはその外乱の影響を小さくでき、良好なプロセス制御を行うことができて内温を安定させることができ、その結果製品の品質が安定する。そして外乱推定部４１において、検出された内温を目標値としかつ外乱のない擬似的な制御系を組んでその制御系内の推定調節器５１からの操作量と制御器３内の主調節器３１の操作量とを比較してその差分を推定外乱として取り出しているので、外乱が未知な場合においても外乱の補償値（フィードフォワード操作量）を正確にかつ容易に決定することができ、プラントの生産性の向上に寄与する。
【００６３】
更に外乱推定部４１において推定した外乱パターンを用いて外乱補償を行うときには、従調節器３２及びプロセスを合わせた制御対象の無駄時間を考慮して、推定された外乱パターンの位相を例えば推定外乱発生器４６により早めており、更にその早めるべく位相を選択できるようにしているので、制御対象の無駄時間が長い場合であっても良好な外乱補償を行うことができる。またプロセス制御に対する高度の知識を必要とせず、運転員が手動操作で経験と勘による制御性以上の外乱抑制性能が発揮される。
【００６４】
上述の実施の形態では、主調節器３１、従調節器３２及び外乱推定部４１としてモデル予測制御を行うものを例としてあげているが、主調節器３１及び従調節器３２については例えばＰＩＤ演算を行う構成であってもよく、主調節器３１及び従調節器３２がＰＩＤ演算を行う場合であっても、操作量ＭＶが発散しない場合には本発明を適用できることをシミュレーションで確認している。
。
【００６５】
以下に上述の実施の形態を用いて実際に計算した主調節器３１の操作量（操作出力）及び推定外乱並びに実際の内温を示す具体例について示しておく。図８は実運転データの操作量ＭＶおよび内温をもとに外乱推定部４１により外乱推定を行った結果の途中計算結果である。外乱推定部４１の推定用調節器の希望応答時間を十分に小さくし従調節器３２とプロセスとを一次遅れ系と見なした擬似制御部５２の出力より得られた外乱推定部内温Ｙ_Ｐ’と実際の内温Ｙ_Ｐとが示されている。図８からも明らかなように外乱推定部内温Ｙ_Ｐ’は内温Ｙ_Ｐにほぼ一致していることから、主調節器３１の操作出力と外乱推定部４１における推定用調節器の操作出力との差がジャケットタンク１に加わった外乱ＤＶ’と見なせる。
【００６６】
図９は図８の計算条件と同様に途中計算結果であり、主調節器３１の操作出力と調節器５２の操作出力とが示されている。この例においては主調節器３１の操作出力の下限値が冷却水の水温として設定されているために、操作出力は８℃未満にはならない。
【００６７】
図１０は式（数７）で示されるように主調節器３１の操作出力と推定用調節器の操作出力との差および内温に加わった温度変化の推定値が示されている。図１０において両者の操作出力の差の変動は急峻であるにも関わらず、推定外乱はプロセスを通過しているため非常に緩やかな温度変化となっている。
【００６８】
図１１は、既知の外乱をジャケットタンク１に加えつつ実運転を実施した一例として、実際に加えた外乱パターン、外乱推定器４１により得られた推定外乱パターン、測定された内温パターンが示されている。既知外乱（実際に加えた外乱）と推定外乱を比較すると誤差は存在するものの、推定外乱は概ね既知外乱を表現しており、外乱補償のフィードフォワード操作量として利用できることが確認された。
【００６９】
図１２は図１１で示した既知外乱をジャケットタンク１に加え、制御器３のみのモデル予測制御（以下、ＭＰＣ制御）および本発明による制御器３に外乱補償器４を加えた外乱補償モデル予測制御（以下、外乱補償ＭＰＣ制御）を行った結果が示されている。図１２の時間レンジ範囲においてＭＰＣ制御および外乱補償ＭＰＣ制御を評価すると、ＭＰＣ制御では目標値４０℃からの最大偏差は各々＋４２．０７℃、−３８．６８℃となりその差は３．３９℃であった。一方、外乱補償ＭＰＣ制御では目標値４０℃からの最大偏差は各々４０．２９℃、−３９．７６℃となりその差は０．５３℃となった。この結果から明らかなように通常のＭＰＣ制御と外乱補償ＭＰＣ制御の制御性能の差は著しく、本発明である外乱補償ＭＰＣ制御の有効性は示された。
【００７０】
図１３はＦＦ演算器４７に加える推定外乱パターンの位相を変化させ、本制御装置のロバスト性についてシミュレーションにより検討を行った結果が示されている。推定外乱パターンの位相を５０％進めて入力すると最大偏差−最小偏差の差は０．１７℃、推定外乱パターンの位相を５０％遅らせて入力すると最大偏差−最小偏差の差は０．４５℃となった。通常のＭＰＣ制御を同様なシミュレーション条件を設定し計算を行った結果、最大偏差−最小偏差の差は３．３９℃であったことを考慮すると外乱補償ＭＰＣ制御は十分なロバスト性を有すると結論付けられた。なお、計算条件としては、従調節器３２を含むプロセスの一次遅れ時定数６０００ｓｅｃ、従調節器３２を含むプロセス無駄時間３８０ｓｅｃとした。
【００７１】
【発明の効果】
以上の説明から明らかなように、本発明によれば、過去の運転より得られた推定外乱パターンを次回以降の運転に反映し、その推定外乱パターンからフィードフォワード操作量を生成し、外乱を打ち消す操作量とするようにしているため、プロセスに加わる外乱を排除でき、良好な制御を行うことができる。そして外乱が未知な場合においても対応できるし、また推定した外乱の位相を進めて（早めて）補償用の外乱パターンを発生させることができるので、プロセスの無駄時間の長さにかかわらず外乱を排除できる。
【図面の簡単な説明】
【図１】本発明に係るプロセス制御装置の実施の形態の全体構成を概略的に示すブロック図である。
【図２】従調節器の操作出力と冷媒バルブ及び熱媒バルブの開度との関係を示す特性図である。
【図３】外乱推定部の内部構成を、外乱推定部と主調節器及び実プロセスとの接続関係と共に示すブロック図である。
【図４】プロセスに加わる外乱を外乱補償器による推定外乱により補償する様子を示すブロック線図である。
【図５】推定外乱の位相が実際の外乱に対して遅れている様子を示す説明図である。
【図６】表示／操作部の画面の一例を示す説明図である。
【図７】上述実施の形態のプロセス制御装置を使用するときの処理の全体の流れを示すフローチャートである。
【図８】外乱補償を行ったときの内温の検出値と内温の推定値とを示す図である。
【図９】主調節器の操作量と外乱推定部内の調節器の操作量とを示す図である。
【図１０】主調節器の操作量と外乱推定部内の調節器の操作量との差、及び推定外乱を示す図である。
【図１１】主調節器の操作量に加わる外乱パターン、その外乱パターンの推定結果（推定外乱パターン）及び外乱が加わった状態における内温の検出値を示す図である。
【図１２】外乱補償を行ったときと行わないときにおける夫々の内温の検出値を示す図である。
【図１３】外乱補償を行ったときの制御系のロバスト性をシミュレーションにより確認した結果を示す図である。
【符号の説明】
【符号の説明】
１ ジャッケットタンク
１１ 反応容器
１２ 撹拌器
１３ ジャケット
１４、１５ 温度検出部
２１ 温調媒体流入管
２２ 温調媒体流出管
２３ 冷媒バルブ
３ 制御器
３１ 主調節器
３２ 従調節器
３３ 加算器
４ 外乱補償器
４１ 外乱推定部
４２ 推定外乱パターン記憶部
４３ 表示／操作部
４４ 外乱データ処理部
４５ 出力外乱パターン記憶部
４６ 推定外乱発生器
４７ ＦＦ演算器
４８ 運転来歴記憶部
５１ 調節器
５２ 疑似制御対象
５３ 加算器[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a process control device that estimates a disturbance pattern applied to a process when performing ford forward control, and converts the disturbance pattern into a feedforward manipulated variable to compensate for the manipulated variable.
[0002]
[Prior art]
Conventionally, feedback control or feedforward control based on PI control or PID control has been known. However, in recent years, in high-value-added, low-mix, high-mix production plans in batch processes, feedback control or feedforward control alone is not sufficient. However, sufficient control performance may not be obtained for unknown disturbances.Therefore, a model predictive control device configured to predict the behavior of a future process using a process model and determine the current manipulated variable has been developed. Many have been proposed. However, the disturbance compensation function of the conventional model predictive control device performs feedforward compensation for measured disturbance and disturbance compensation for estimated disturbance, assuming that unmeasured disturbance is constant. For this reason, there is a structural problem that the control performance is not good with respect to process characteristic values that fluctuate with time and unknown disturbances.
On the other hand, Patent Literature 1 discloses that as a means of disturbance compensation, an error between a process value and a process value of a prediction model is treated as an unmeasurable disturbance, thereby improving controllability with respect to a change in dynamic characteristics of a process and a disturbance that cannot be measured. Has been described. Specifically, a disturbance filter calculates the deviation between the model output obtained from the model unit based on the operation output from the operation output calculation unit and the process amount from the process, and estimates the disturbance obtained based on this deviation. The predicted value of the process amount including the signal is input to the operation output operation unit, and the operation output operation unit calculates the operation output so that the predicted value of the process amount matches the predicted value of the reference trajectory. Is a method of compensating for
[0003]
[Patent Document 1]
JP-A-5-265514: FIG. 1, paragraphs 0012 and 0013
[0004]
[Problems to be solved by the invention]
Handling the error between the above process value and the process value of the prediction model as an unmeasurable disturbance online can be applied when the process does not include dead time or the dead time is short, but there is a dead time in the process. In this case, the operation result calculated by the disturbance filter is based on the process amount obtained by inputting the operation amount to the process and then delaying by the dead time, so that the operation output compensated for the disturbance is input to the process. Since the process value oscillates because the process timing lags behind the timing when a disturbance is added to the process, there is a concern that the process control may be unstable by performing the disturbance compensation, especially when the dead time is long. , The control itself is not established.
[0005]
The present invention has been made based on such a background, and an object of the present invention is to provide a process control device capable of performing good control even when disturbance is applied to a process. Still another object of the present invention is to provide a process control device capable of performing good control when a disturbance is applied to a process regardless of the length of the dead time of the process.
[0006]
[Means for Solving the Problems]
The present invention provides a process control device that controls a process based on an operation amount output from a control adjustment unit,
The disturbance pattern added to the process based on the difference between the manipulated variable output from the control adjustment unit when the process is performed and the manipulated variable obtained by using the control amount obtained when the process is performed as the target value is calculated. A disturbance estimating unit for estimating,
A storage unit for storing the disturbance pattern estimated by the disturbance estimation unit,
An estimated disturbance output unit that generates a disturbance pattern based on data stored in the storage unit in an operation cycle after the operation cycle in which the disturbance pattern is estimated, and outputs the disturbance pattern as a feedforward operation amount;
Means for adding the feedforward operation amount to the operation amount output from the control adjusting section as a disturbance compensation amount.
[0007]
In the present invention, "generating a disturbance pattern based on data stored in the storage unit in an operation cycle after an operation cycle in which a disturbance pattern is estimated" means, for example, a disturbance pattern when a first batch process is performed. Is estimated, and a disturbance pattern is generated when the process of the second batch or later is performed. The data stored in the storage unit may be directly generated as a disturbance pattern.For example, a plurality of previously stored disturbance patterns may be processed and, for example, averaged to generate a disturbance pattern. . In any case, when a process includes a dead time, the disturbance pattern output from the estimated disturbance output unit advances the phase of the disturbance pattern stored in the storage unit by an amount corresponding to the dead time. It is desirable to (early). Further, in the present invention, since the disturbance added to the process is regarded as a disturbance added to the operation amount, `` adding the feedforward operation amount as the disturbance compensation amount to the operation amount output from the control adjusting unit '' means That is, the disturbance included in the operation amount output from the control adjusting unit is canceled (subtracted) by the feedforward operation amount.
[0008]
Further, in the present invention, a plurality of disturbance patterns may be prepared based on the data stored in the storage unit, and a means for selecting a disturbance pattern to be used from the plurality of disturbance patterns may be provided. . Further, as an example of the present invention, the disturbance estimating unit includes an estimating adjusting unit having a control amount as a target value, and a control object controlled by the operating amount of the controlling adjusting unit, having an operation amount from the estimating adjusting unit as an input. Means for calculating and processing an input value by a transfer function equivalent to and an addition unit for extracting a difference between an operation amount from the control adjustment unit and an operation amount from the estimation adjustment unit as an estimated disturbance. Prepare,
The estimation adjustment unit may be configured to output the operation amount such that the output value of the transfer function in the disturbance estimation unit matches the set reference trajectory. In this case, for example, the transfer function in the disturbance estimation unit does not include a dead time. The control adjuster and the estimation adjuster have, for example, the same input / output characteristics.
The term "equivalent input / output characteristics" as used herein means that, for example, if the control adjustment unit and the estimation adjustment unit that perform model predictive control are used, the control amount prediction formula and the reference trajectory are the same in both. It is.
[0009]
Further, a selection for selecting one of a mode in which the disturbance is estimated by the disturbance estimating unit while performing the process, and a mode in which the disturbance is estimated by the disturbance estimating unit after the process is completed based on data stored during the process. Means may be provided, or means for displaying the disturbance pattern estimated by the disturbance estimation unit may be provided.
[0010]
Another invention is a process control method for controlling a process based on an operation amount output from a control adjustment unit,
The disturbance pattern added to the process based on the difference between the manipulated variable output from the control adjustment unit when the process is performed and the manipulated variable obtained by using the control amount obtained when the process is performed as the target value is calculated. Estimating,
Storing the disturbance pattern estimated in this step;
In a driving cycle after the driving cycle in which the disturbance pattern is estimated, a disturbance pattern is generated based on the already stored estimated disturbance pattern, and a step of outputting the disturbance pattern as a feedforward manipulated variable,
Adding the feedforward operation amount as a disturbance compensation amount to the operation amount output from the control adjustment unit.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a process control device according to the present invention will be described in detail with reference to the accompanying drawings. This embodiment is an example applied to control of the internal temperature of a jacket tank applied to a chemical plant. In FIG. 1, reference numeral 1 denotes a jacket tank 1, which is a reaction device, which allows a predetermined chemical reaction to proceed by appropriate temperature control after the introduction of raw materials, thereby converting the product into a product having predetermined characteristics. The jacket tank 1 includes a reaction vessel 11 into which the raw material is charged, a stirrer 12 for uniformly dispersing the raw material and making the temperature distribution uniform, and a flow path for the temperature control medium around the reaction vessel 11. The jacket 13 is provided, and heat is removed and heated by the temperature gradient between the temperature control medium through which the jacket 13 flows and the contents inside the reaction vessel 11 to perform heat exchange. The temperature in the container 11 is controlled by the controller 3 to a predetermined temperature.
[0012]
The jacket 13 is connected to an inflow pipe 21 serving as an inflow path for flowing the temperature control medium and an outflow pipe 22 serving as an outflow path for flowing out the temperature control medium. The conditioning medium returns to the outflow pipe 22 via, for example, a circulation tank (not shown). In this example, temperature-regulated water is used as a temperature-regulated medium, and a medium for regulating the temperature of the temperature-regulated water, for example, a refrigerant supply pipe 23 a and a heat medium supply pipe so that a refrigerant and a heat medium are supplied to the inflow pipe 21. 23 b is connected to the inflow pipe 21.
The cooling water as the refrigerant and the steam or the hot water as the heat medium are appropriately selected by a slave controller 32 included in the controller 3, and the refrigerant is a flow control unit. The heat medium is supplied to the inflow pipe 21 by being controlled by the refrigerant valve 23 and the heat medium valve 24 which is a flow control unit, and the temperature in the reaction vessel 11 is adjusted via the temperature control medium. The coolant may be a fluid other than cold water, and the heat medium may be a fluid other than hot water. Reference numeral 14 denotes a temperature detection unit for detecting the temperature in the reaction vessel 11, reference numeral 15 denotes a temperature detection unit for detecting the temperature of the temperature control medium (entrance-side temperature control medium) in the inflow pipe 21, and reference numeral 16 denotes the outflow pipe 22. It is a temperature detection unit that detects the temperature of the temperature control medium (exit side temperature control medium) inside.
[0013]
In FIG. 1, reference numeral 3 denotes a controller, which is composed of a main controller 31 and a sub controller 32 which are cascaded with each other. In this example, the main controller 31 forms a control controller, and the control object is a process with the sub controller 32. The control cycle of the main controller 31 is longer than the control cycle of the sub controller 32. It is set large. Further, a temperature target value set by a setting unit (not shown) and a temperature detection value (an internal temperature that is a control amount) from the temperature detection unit 14 are input to the main controller 31, and an operation amount MV is output. The manipulated variable MV is a set value of the slave controller 32, here, a target temperature of the internal temperature of the reaction vessel 11.
[0014]
The main controller 31 employs the model predictive control, and outputs the manipulated variable MV at which the set reference trajectory has the same process value at each control cycle. In this model predictive control, for example, as shown in FIG. 2A, a reference trajectory yR (t + j) that gradually approaches the target temperature of the internal temperature is calculated starting from the current detection value y (t) of the internal temperature. A predicted value yP (t + j) of the future internal temperature is obtained based on the detected value y (t) and the prediction formula, and the predicted value yP (t + j) of the internal temperature is obtained in a matching section (for example, a section from n steps to m steps ahead). ) Is determined so as to approach the reference trajectory yR (t + j) as much as possible at the time of a predetermined step after the current time (operation amount), and only the operation amount corresponding to the current time among the obtained operation amounts is output. The main controller 31 is configured to repeat this procedure. The internal model of the main controller 31 is defined as a model in which the slave controller 32 and the process are approximated by a first-order delay time. The actual processes are a) a process in which a heat medium or a refrigerant is mixed with a circulating temperature control medium, b) a process in which heat is transferred from the temperature control medium into the reaction vessel 11, c) a process in the reaction vessel 11. The process can be roughly classified into a heat generation process, but since the modeling of c) is difficult, the process referred to here means a) and b).
[0015]
The slave controller 32 receives the manipulated variable MV output from the main controller 31 as an internal temperature set value, and also detects, for example, each temperature detected value from the temperature detectors 15 and 16, for example, a moving average at each temperature detected value. Is input to perform a predetermined operation on these values. The slave controller 32 employs model predictive control similarly to the main controller 31, and outputs an operation amount such that the process value matches the set reference trajectory in each control cycle. The internal model of the slave controller 32 is defined as a model in which the jacket inlet temperature generated when the valves 23 and 24 are operated is approximated by a first-order delay time.
[0016]
The control target of the slave controller 32 is the opening degree of the refrigerant valve 23 or the heat medium valve 24. The slave controller 32 includes a split range process so that the refrigerant valve 23 or the heat medium valve 24 is not opened at the same time. ing. FIG. 2B is a diagram illustrating an example of a split range that defines a relationship between the operation output of the slave controller 32 and the opening degrees of the valves 23 and 24. In this example, the operation output increases from 0% to 50%. As the pressure increases, the opening of the refrigerant valve 23 is set to go from 100% to 0%, and when the operation output is 50% or more, the opening of the heat medium valve 24 is set to go from 0% to 100%.
[0017]
Next, in FIG. 1, reference numeral 4 denotes a disturbance compensator. The disturbance compensator 4 has a control performance for overcoming a structural problem of a model predictive control device which is a process control device. It is newly provided to realize better control performance so as not to decrease. The controller 3, the disturbance compensator 4, the temperature detectors 14, 15, 16 and the valves 23, 24 and the like in FIG. 1 correspond to a process control device, and each part is described by a block. Alternatively, the processing is actually executed by software. The disturbance compensator 4 can be roughly classified into a part relating to estimation of a disturbance pattern and a part for compensating the operation output of the main controller 31 based on the estimated disturbance.
[0018]
First, the former part related to disturbance pattern estimation includes a disturbance estimation unit 41 and an estimated disturbance pattern storage unit 42 for storing the estimated disturbance pattern. As shown in FIG. 3, the disturbance estimating unit 41 performs an operation amount (operation output) MV of the main controller 31 and an internal temperature Y that is a control amount. _P (Detected temperature value) as an input, and outputs an estimated disturbance DV ′. The transfer function G of the control unit 33 of the estimation controller 51 and the main controller 31 is configured. _P Transfer function G equivalent to _P The operation amount of the estimation controller 51 is calculated by calculating the operation amount from the estimation controller 51, that is, the operation amount MV of the estimation controller 51 and the operation amount MV of the main controller 31 are compared with each other. And an adder 53 for taking the deviation. Here, the control target 33 refers to a combination of the slave controller 32 and a process (a product generation process performed by controlling a temperature control medium). Transfer function G _P Is expressed as a transfer function approximating a first order lag model to the slave controller 32, the step of mixing the refrigerant or the heat medium with the circulating temperature control medium, and the heat transfer of the jacket tank 1.
[0019]
The estimation controller 51 employs model predictive control similarly to the master controller 31 and the slave controller 32, and is configured in the same manner as the master controller 31, and the set reference trajectory matches the process value. Is output for each control cycle. Therefore, the internal model of the controller 51 for estimation is defined as a model obtained by approximating the slave controller 32, the step of mixing the refrigerant or the heat medium with the circulating temperature control medium, and the heat transfer between the jacket tank 1 and the first-order delay. Is done. This estimating controller uses a transfer function G _P Is always set to be as short as possible, and the control result (internal temperature) Y obtained from the control target 33 _P Is the target value, and the transfer function G _P 'Control amount (internal temperature) Y which is a control result obtained through (simulated control object) Y _P And an operation amount MV according to the target value.
[0020]
If a disturbance is applied to the process, for example, if an exothermic reaction occurs in the reaction vessel 11, the internal temperature Y _P Fluctuates, and it can be considered that this fluctuation is caused by adding the disturbance DV to the operation amount MV as shown in FIG. The disturbance estimating unit 41 attempts to estimate the disturbance DV, and creates a control system corresponding to the main controller 31 and the control target 33 as a pseudo control system by the estimating controller 51 and the arithmetic processing unit 52. I have. Since this simulated control system does not include any disturbance, if there is no disturbance even in the actual control system (if the DV shown in FIG. 3 does not exist), theoretically, the operation amount MV of the main controller 31 and the adjustment amount are adjusted. The operation amount MV ′ of the device becomes equal, and the addition result (deviation between MV and MV ′) in the adder 53 is zero. However, if a disturbance DV is applied in the actual control system, the sum of MV and MV ′ is The deviation appears as DV '. That is, this DV ′ is an estimated disturbance corresponding to the disturbance DV. As will be described in detail later, the calculation results at this time are shown in FIGS.
[0021]
The above description is for the case where the disturbance is estimated online, but the disturbance may be estimated offline. In this case, the manipulated variable MV and the internal temperature in the operation cycle are stored in the operation history storage unit 48 as described later, and the disturbance is not estimated during the operation cycle, and the operation history is stored later according to the instruction of the operator. The disturbance estimation unit 41 may call the data (the operation amount MV and the internal temperature) in the unit 48 and estimate the disturbance in the driving cycle.
[0022]
Next, a part of the disturbance compensator 4 for compensating the operation output of the main controller 31 based on the estimated disturbance will be described. Before that, a description of the disturbance will be added. Generally, an operation amount pattern obtained as a control result includes a disturbance applied when the control is performed and an operation result output to cancel the disturbance. The disturbance applied to the process can be classified into a reproducible disturbance and a non-reproducible disturbance. The reproducible disturbance corresponds to a disturbance generated in the process, and includes a disturbance caused by the input of raw materials, a disturbance caused by the progress of the reaction, and the like. Since these disturbances are disturbances that depend on the recipe for each product, they can be generally assumed to be reproducible disturbances.
In other words, the manufacturing process is determined for each product type, and if the manufacturing process is of the same type, the input of raw materials and the heat generation pattern can be assumed to be the same. Can be considered.
[0023]
On the other hand, disturbances without reproducibility include random components such as variations in raw materials, fluctuations in cooling water pressure and cooling water temperature, fluctuations in steam pressure and steam temperature, and can be regarded as disturbances without reproducibility. An object of the present invention is to estimate a disturbance pattern for a reproducible disturbance, and to obtain an appropriate feedforward operation amount for the obtained estimated disturbance pattern. That is, in the batch process, since a reproducible disturbance is added, it is reasonable to estimate a disturbance pattern in advance and apply feedforward compensation to cancel the estimated disturbance pattern. It is based on this idea.
[0024]
Therefore, a detailed description will be given of how disturbance is compensated based on the estimated disturbance pattern obtained by the estimated disturbance pattern storage unit 42. The disturbance compensator 4 has a display function and an operation by an operator as shown in FIG. A display / operation unit 43 having functions, a disturbance data processing unit 44, an output disturbance pattern storage unit 45, an estimated disturbance generator 46, an FF (feedforward operation amount) calculator 47, and a driving history storage unit 48 And
[0025]
One of the simple uses of the disturbance compensator 4 is, for example, when a raw material is charged into the reaction vessel 11 to obtain a product as a reaction product, and when the first batch processing is performed, the disturbance estimating unit is used. 41, the disturbance pattern is obtained as described above and stored in the estimated disturbance storage unit 42, and the estimated disturbance pattern acquired in the first batch is obtained when performing the processing of the second and subsequent batches in the same type of process. Is subtracted from the operation amount of the main controller 31 to cancel the disturbance. Actually, when the estimated disturbance pattern obtained in the first batch is not used as it is, but is selected from among the disturbance patterns obtained in several operation cycles (batch processing) or processing is applied to those disturbance patterns For example, the average value of a plurality of disturbance patterns may be obtained. More specifically, the operation is performed a plurality of times in advance for each production recipe to estimate the disturbance, and based on the acquired disturbance, for example, a plurality of representative disturbance patterns are determined, and the operation is performed when actually producing the product. The member may select a disturbance pattern to be used from the plurality of disturbance patterns. For example, as shown in FIG. 4, which will be described later, the operator selects the number of the production recipe using the display / operation unit 43, and further selects one of several disturbance patterns assigned to the production recipe. A disturbance pattern to be used is selected, and a use mode of the disturbance pattern is selected. Instead of preparing a plurality of disturbance patterns in the production recipe, one disturbance pattern may be assigned to each product type (brand) to be obtained. The use mode of the disturbance pattern includes a phase of the disturbance pattern, a start timing of disturbance compensation, and a time of disturbance compensation, which will be described later.
[0026]
The display / operation unit 43 is configured so that the operator selects an estimated disturbance pattern as described above, or performs a predetermined process on the already acquired estimated disturbance pattern, for example, an averaging process of a plurality of estimated disturbance patterns. The estimated disturbance pattern instructed and selected or processed is stored in the output disturbance pattern storage unit 45. Specifically, for example, a touch panel, a keyboard and a screen unit (CRT, liquid crystal panel, etc.) are combined. Things correspond.
[0027]
The display / operation unit 43 includes a screen for selecting and processing the estimated disturbance pattern, a screen for displaying the estimated disturbance pattern stored in the estimated disturbance pattern storage unit 42,
A screen displaying the estimated disturbance pattern after the predetermined processing is performed, the operation amount and control result from the main controller 31 acquired by the operation history storage unit 48, such as the internal temperature, the opening degrees of the valves 23 and 24, and the operation A screen for displaying a driving history such as a timing, a screen for designating whether the disturbance estimating unit 41 is to estimate a disturbance online (performing a disturbance estimation during the driving cycle), and a driving in a past driving cycle. A screen for allowing the disturbance estimating unit 41 to estimate the disturbance based on the data in the history storage unit 48 (for estimating the disturbance by offline) is provided. Information can be entered. If data registration is specified by the operator, the driving history and estimated disturbance pattern stored during the driving cycle are registered, but if data registration is not specified, the driving history and estimated disturbance of the cycle are registered. The pattern is erased.
[0028]
The disturbance data processing unit 44 selects an estimated disturbance pattern corresponding to the disturbance pattern selected by the operator via the display / operation unit 43 from the data in the estimated disturbance pattern storage unit 42, and stores the selected disturbance pattern in the output disturbance pattern storage unit 45. For example, when a production recipe of a product is selected, an estimated disturbance pattern corresponding to the recipe is selected. When the display / operation unit 43 designates to perform some processing on the estimated disturbance pattern, the disturbance data processing unit 44 processes the data in the estimated disturbance pattern storage unit 42 in accordance with the designation. And sends the processed data (estimated disturbance pattern) to the output disturbance pattern storage unit 45.
[0029]
The estimated disturbance generator 46 reads data from the output disturbance pattern storage unit 45 and outputs an estimated disturbance pattern, and the FF calculator 47 converts this output data into a feedforward manipulated variable. In FIG. 1, reference numeral 33 denotes an adder 33, which adds the feedforward operation amount from the FF operation unit 47 to the operation amount MV of the main controller 33. In this example, since the slave controller 32 includes a differential element, the FF calculator 47 changes the sign of the estimated disturbance pattern added to the process and then advances the phase by the dead time of the slave controller 32 and the process. It is output as a feedforward manipulated variable. In this example, the estimated disturbance generator 46 and the FF calculator 47 constitute an estimated disturbance output unit 40 for outputting the estimated disturbance pattern as a feedforward manipulated variable.
[0030]
FIG. 4 shows a state in which disturbance applied to the process is compensated by the disturbance compensator 4. That is, the estimated disturbance pattern stored in the output disturbance pattern storage unit 45 is read by the estimated disturbance generator 46, input to the adder 33 as the estimated disturbance DV ′ through the FF calculator 47, and operated by the main controller 31. It is subtracted from the quantity MV. On the other hand, a disturbance is added to the process, and the disturbance DV can be regarded as being added to the manipulated variable MV from the main controller 31. As a result, the estimated disturbance DV ′ is obtained as a compensation amount for the disturbance DV added to the process. Because of this, the disturbance looks like DV is offset and the internal temperature Y _P Stabilizes to reach the target temperature.
[0031]
Here, since there is a delay time from when the operation amount is input from the main controller 31 to the slave controller 32 until the internal temperature responds, that is, the transfer function G of the slave controller 32 and the process is combined. _P Since there is a dead time L, as shown in FIG. 5, when the disturbance DV is added to the operation amount MV from the main controller 31, the disturbance DV ′ estimated by the disturbance estimating unit 41 when the disturbance DV is added is the disturbance DV. It is delayed by the dead time L from the added timing.
Therefore, the estimated disturbance pattern must be added to the manipulated variable MV by advancing by the dead time L, instead of being directly added to the manipulated variable MV. Therefore, the estimated disturbance unit 46 reads the estimated disturbance data from the output disturbance pattern storage unit 45 and The estimated disturbance value is sequentially output in advance of the time L by the control period of the main controller 31.
[0032]
Here, an example of a setting screen on the display / operation unit 43 is shown in FIG. The upper screen in the setting screen is for selecting a production recipe for manufacturing a product, and the recipe information for each product is described. The screen on the lower side is used to select the estimated disturbance pattern and set the use mode.The presence or absence of disturbance estimation, data collection, classification, product name, corresponding disturbance pattern, trigger tag, phase, disturbance compensation Time, data creation date, etc. are displayed, and the operator can select which disturbance compensation data (estimated disturbance pattern) to use. Trigger is an abbreviation for trigger tag, which means the timing of charging reactants, catalysts, and the like, and phase means the dead time of the process including the slave controller 32. The disturbance compensation start timing is set from these trigger tags and phase information. Compensation is an abbreviation for disturbance compensation time, and is the time during which the feedforward manipulated variable signal is output. In the screen of FIG. 6, the unit of the dead time and the disturbance compensation time is “second”.
[0033]
Further, the setting screen of FIG. 6 includes an operation portion for selecting whether or not to perform the estimation of the disturbance pattern. When the data collection is set to “Yes” and the estimation of the disturbance pattern is set to “Execution”, The disturbance is estimated online, that is, during batch processing (during operation), and the estimated disturbance pattern is registered. On the other hand, if the estimation of the disturbance pattern is set to “do not perform”, the disturbance estimation is not performed, but in this case, if the data collection is performed with the data collection set to “Yes”, after the operation is completed, When an instruction for estimating the disturbance is input on a screen (not shown) of the display / operation unit 43, the disturbance at the time of the previous operation can be estimated based on the already collected data. That is, in this embodiment, so-called online disturbance estimation and offline disturbance estimation can be selected, and the display / operation unit 43 also serves as a selection unit for selecting one of them. Note that the compensation coefficient in the setting screen of FIG. 6 is a coefficient for setting the disturbance compensation amount applied to the adder 33 to, for example, 0 to 100%. The value of 80% of the disturbance compensation amount read from the storage unit 45 is the actual compensation amount.
[0034]
Next, returning to FIG. 3, the estimation of the disturbance will be considered by using a mathematical expression. Assuming that the estimated disturbance DV ′ is input to the stage preceding the control target 33 of the main controller 31, the disturbance DV with true reproducibility is assumed. ₁ And true disturbance DV without reproducibility ₂ And the error ε due to model mismatch or process non-linearity is:
[0035]
(Equation 1)

[0036]
Most of the disturbances that occur with the progress of the steps in a general batch process are considered to have a high contribution of the heat of reaction due to heat generation and heat absorption. ₁ >> DV ₂ It becomes. The actual internal temperature Y _P And an internal temperature Y which is a calculation result (control result) of the calculation processing unit 52 which is a target of the pseudo control. _P 'Is formulated as follows:
[0037]
(Equation 2)

[0038]
[Equation 3]

[0039]
G _P ≒ G _P ', Y _p And Y _p Is given by the following equation.
[0040]
(Equation 4)

[0041]
On the other hand, the controller for estimation is the internal temperature of the jacket tank 1, that is, Y _p Is a set value, and the transfer function G that approximates the heat transfer of the controlled object consisting of the slave controller 32 and the process described above to a first-order lag model _P 'Control. Here, the set value Y _P Control amount Y _P 'Depends on the reference trajectory set by the estimation controller 51, but Y _P Follows a little with a change in
[0042]
(Equation 5)

[0043]
In the arithmetic processing unit 52, which is a pseudo control system corresponding to the slave controller 32 and the process, a transfer function G that approximates the heat transfer to a first-order lag model _P 'Constitutes a control system that does not include dead time. _P 'Can be set to infinitely fast response time. If the desired response time of the estimation controller 51 is made sufficiently small, the following equation is obtained.
[0044]
(Equation 6)

[0045]
Therefore, the following equation is obtained from the relationship between Equation (Equation 4) and Equation (Equation 5).
[0046]
(Equation 7)

[0047]
(Equation 8)

[0048]
Therefore, the estimated disturbance DV ′ was derived from the difference between the operation amount of the main controller 31 and the operation amount of the estimation controller 51. This estimated disturbance DV 'is used for the feedforward operation amount of disturbance compensation as described above.
[0049]
However, since the estimated disturbance DV ′ is obtained from the temperature of the reaction vessel 11, taking into account the dead time θ of the reaction vessel 11, the DV applied before the reaction vessel 11 is given by the following equation.
[0050]
(Equation 9)

[0051]
The conversion into the feedforward manipulated variable can be performed by adding the manipulated variable of the main controller 31 to cancel the estimated disturbance DV ′. _F Is given by
[0052]
(Equation 10)

[0053]
In other words, if the phase of the dead time of the process is advanced to that obtained by changing the sign of the estimated disturbance DV 'and added to the operation amount of the main controller 31, the added disturbance DV' is canceled and disturbance compensation can be easily realized. . However, disturbance compensation based on the estimated disturbance pattern is realized after the next batch operation of the same recipe for which disturbance estimation has been performed.
[0054]
Since the equation (Equation 8) is derived from the result assuming that a disturbance has been applied to the preceding stage of the slave controller 32, the actually observable internal temperature DV _temp To convert to DV ', the transfer function G _P '.
[0055]
(Equation 11)

[0056]
The estimated disturbance generator 46 advances the phase corresponding to the dead time of the process, and sequentially outputs the estimated disturbance value in accordance with the control cycle of the main controller 31. The FF calculator 47 receives DV ′ as an input, and obtains a disturbance compensation operation amount D according to Expression (Equation 10). _F Is calculated and added to the operation output of the main controller 31. In the same recipe, DV '· e ^θs ≒ -D _F Therefore, disturbance compensation can be easily realized. On the other hand, when the disturbance compensation is taken into the control, the deviation from the set value mainly depends on the second and third terms on the right side of the equation (Equation 1).
[0057]
Next, an overall flow of processing when the process control device according to the above-described embodiment is implemented using a computer will be described with reference to the flowchart in FIG. In FIG. 5, when the process control device is started, the display / operation unit 43 waits for an input operation from an operator or an input operation to a remote device by a communication program by an operator (step S1). When the production of the product is selected by the input operation, a recipe is confirmed on the display screen (see FIG. 6) for the information on the product to be produced, and disturbance compensation data is designated (step S2). In the operation, the batch process proceeds based on the recipe information. In this example, another computer such as DCS has a function of the operation sequence processing. The user selects which estimated disturbance pattern obtained in the past is to be used as the disturbance compensation data, and sets the trigger tag, the phase, and the compensation time. In this example, the estimated pattern to be used is transferred from the estimated disturbance pattern storage unit 42 in the disturbance compensator 4 to the output disturbance pattern storage unit 45 via the disturbance processing unit 44 in advance before the operation is started.
[0058]
Next, it is determined whether or not data collection is to be performed (step S3). If "data collection" is selected, the driving data is unconditionally stored in the driving history storage unit 48 at the time of driving to be performed, and disturbance is performed. The disturbance estimated by the estimation unit 41 is stored in the estimated disturbance pattern storage unit 42 (Step S4). The operation storage time can be arbitrarily set by the display / operation unit 43, and information on the entire operation time can be stored or only a part thereof can be stored. Then, the raw material is put into the jacket tank 1, and at the same time as the operation is started, the control of the jacket tank 1 is started by the controller 3 to manufacture the product (step S4). Until the disturbance compensation start time) is reached, the controller 3 operates as normal model prediction control (MPC control), and the disturbance compensation MPC control does not operate. From the time when the disturbance compensation start time is reached, the estimated disturbance value is output from the estimated disturbance generator 46 for each control cycle, and is changed to the feedforward manipulated variable by the FF calculator 47. It is output to an adder 33 on the output side of 31.
[0059]
As a result, the manipulated variable calculated from the internal temperature (detected value) and the target value of the internal temperature by the main controller 31 and the feedforward manipulated variable from the FF calculator 47 are added to the secondary controller 32. Is output, and thus disturbance compensation is performed (step S4). Until the disturbance compensation target time ends, the process of outputting the estimated disturbance value, changing to the feedforward operation amount, and adding the operation amount and the operation amount from the main controller 31 are repeated for each control cycle. Since the data collection is set, the driving history data and the estimated disturbance pattern collected at the time of driving are registered (determined in the storage) in the driving history storage unit 48 and the estimated disturbance pattern storage unit 42 after the operation is completed, respectively (step). S5). If data collection is not selected in step S3, only product manufacturing is performed (step S6), and disturbance compensation, disturbance estimation data collection, and driving history data collection are not performed.
[0060]
By the way, by performing disturbance compensation, no disturbance should be generated theoretically. However, actually, when the disturbance is estimated by the disturbance estimating unit 41, a disturbance pattern may be obtained. This disturbance pattern is a disturbance that still occurs when disturbance compensation is performed due to, for example, subtle differences in the properties of the raw materials and the like. For example, using the disturbance estimated during the first batch processing (operation cycle), The second batch processing may be performed while the disturbance is compensated, and the estimated disturbance pattern obtained at this time and the estimated disturbance pattern obtained at the first time may be added to perform the third batch processing. .
[0061]
On the other hand, when the operator does not select the product manufacturing in step S1 and selects the off-line disturbance estimation in step S7, for example, the internal temperature corresponding to the control amount which is the driving history data in the selected past driving cycle. A disturbance pattern is estimated by the disturbance estimating unit 41 based on the (detected value) and the operation amount of the main controller 31 (step S8), and registered in the estimated disturbance pattern storage unit 42 (step S5).
[0062]
According to the above-described embodiment, the estimated disturbance pattern obtained in the past operation is used, converted into the feedforward operation amount in the next and subsequent operations, and the disturbance with respect to the operation amount from the main controller 31 is canceled. As a result, the disturbance added to the process can be eliminated or the influence of the disturbance can be reduced, good process control can be performed, the internal temperature can be stabilized, and as a result, the product quality can be reduced. Stabilize. The disturbance estimating unit 41 sets the detected internal temperature as the target value, forms a pseudo control system without disturbance, and operates the operation amount from the estimation controller 51 in the control system and the main controller in the controller 3. 31 and the difference is taken out as the estimated disturbance, the disturbance compensation value (feedforward manipulated variable) can be accurately and easily determined even when the disturbance is unknown, and the plant Contributes to the improvement of productivity.
[0063]
Further, when performing disturbance compensation using the disturbance pattern estimated by the disturbance estimating unit 41, the phase of the estimated disturbance pattern is determined, for example, by considering the dead time of the control target including the slave controller 32 and the process. Since the phase is advanced by the device 46 and the phase can be selected to further advance the phase, good disturbance compensation can be performed even when the control target has a long dead time. In addition, it is not necessary to have a high level of knowledge on process control, and the operator can exhibit disturbance suppression performance more than controllability based on experience and intuition by manual operation.
[0064]
In the above-described embodiment, the main controller 31, the slave controller 32, and the disturbance estimating unit 41 that perform model prediction control are described as an example. However, the PID calculation is performed for the master controller 31 and the slave controller 32, for example. It is confirmed by simulation that the present invention can be applied when the operation amount MV does not diverge, even when the main controller 31 and the slave controller 32 perform the PID calculation. .
.
[0065]
Hereinafter, a specific example showing the operation amount (operation output), estimated disturbance, and actual internal temperature of the main controller 31 actually calculated using the above-described embodiment will be described. FIG. 8 shows an intermediate calculation result of the result of the disturbance estimation performed by the disturbance estimation unit 41 based on the operation amount MV and the internal temperature of the actual operation data. The desired response time of the estimation controller of the disturbance estimator 41 is made sufficiently small, and the slave estimator 32 and the process are regarded as a first-order lag system. _P 'And the actual internal temperature Y _P Are shown. As is clear from FIG. _P 'Is the internal temperature Y _P , The difference between the operation output of the main controller 31 and the operation output of the estimation controller in the disturbance estimator 41 can be regarded as the disturbance DV ′ applied to the jacket tank 1.
[0066]
FIG. 9 shows an intermediate calculation result similarly to the calculation conditions of FIG. 8, and shows the operation output of the main controller 31 and the operation output of the controller 52. In this example, since the lower limit of the operation output of the main controller 31 is set as the temperature of the cooling water, the operation output does not become less than 8 ° C.
[0067]
FIG. 10 shows the difference between the operation output of the main controller 31 and the operation output of the estimation controller and the estimated value of the temperature change added to the internal temperature, as shown by the equation (Equation 7). In FIG. 10, although the fluctuation of the difference between the two operation outputs is steep, the estimated disturbance is a very gradual temperature change because the estimated disturbance passes through the process.
[0068]
FIG. 11 shows an actually applied disturbance pattern, an estimated disturbance pattern obtained by the disturbance estimator 41, and a measured internal temperature pattern, as an example of actual operation performed while adding a known disturbance to the jacket tank 1. ing. A comparison between the known disturbance (actually added disturbance) and the estimated disturbance shows that, although there is an error, the estimated disturbance generally represents the known disturbance and can be used as a feedforward manipulated variable for disturbance compensation.
[0069]
FIG. 12 shows a model prediction control (hereinafter, MPC control) of only the controller 3 by adding the known disturbance shown in FIG. 11 to the jacket tank 1, and a disturbance compensation model prediction in which the disturbance compensator 4 is added to the controller 3 according to the present invention. The result of performing the control (hereinafter, disturbance compensation MPC control) is shown. When the MPC control and the disturbance compensation MPC control are evaluated in the time range of FIG. 12, the maximum deviation from the target value of 40 ° C. is + 42.07 ° C. and −38.68 ° C., respectively, and the difference is 3.39 ° C. there were. On the other hand, in the disturbance compensation MPC control, the maximum deviation from the target value of 40 ° C. was 40.29 ° C. and −39.76 ° C., respectively, and the difference was 0.53 ° C. As is apparent from these results, the difference in control performance between the normal MPC control and the disturbance compensation MPC control is remarkable, and the effectiveness of the disturbance compensation MPC control according to the present invention is shown.
[0070]
FIG. 13 shows the result of changing the phase of the estimated disturbance pattern applied to the FF calculator 47 and examining the robustness of the control device by simulation. When the phase of the estimated disturbance pattern is advanced by 50%, the difference between the maximum deviation and the minimum deviation is 0.17 ° C. When the phase of the estimated disturbance pattern is delayed by 50%, the difference between the maximum deviation and the minimum deviation is 0.45 ° C. became. As a result of setting a similar simulation condition for normal MPC control and calculating, it was concluded that the disturbance compensation MPC control has sufficient robustness considering that the difference between the maximum deviation and the minimum deviation was 3.39 ° C. Attached. The calculation conditions were a first-order lag time constant of 6000 sec for the process including the slave controller 32 and a dead time of 380 sec for the process including the slave controller 32.
[0071]
【The invention's effect】
As is apparent from the above description, according to the present invention, the estimated disturbance pattern obtained from the past operation is reflected in the next and subsequent operations, the feedforward operation amount is generated from the estimated disturbance pattern, and the disturbance is canceled. Since the manipulated variable is used, disturbance applied to the process can be eliminated, and good control can be performed. In addition, it is possible to cope with the case where the disturbance is unknown, and it is possible to advance (earlier) the phase of the estimated disturbance to generate a disturbance pattern for compensation. Can be eliminated.
[Brief description of the drawings]
FIG. 1 is a block diagram schematically showing an overall configuration of an embodiment of a process control device according to the present invention.
FIG. 2 is a characteristic diagram illustrating a relationship between an operation output of a slave controller and the opening degrees of a refrigerant valve and a heat medium valve.
FIG. 3 is a block diagram showing an internal configuration of a disturbance estimating unit together with a connection relationship between the disturbance estimating unit, a main controller, and an actual process.
FIG. 4 is a block diagram showing a state in which a disturbance applied to a process is compensated by an estimated disturbance by a disturbance compensator.
FIG. 5 is an explanatory diagram showing a state in which the phase of an estimated disturbance is behind the actual disturbance.
FIG. 6 is an explanatory diagram illustrating an example of a screen of a display / operation unit.
FIG. 7 is a flowchart illustrating an overall flow of a process when using the process control device of the above embodiment.
FIG. 8 is a diagram showing a detected value of an internal temperature and an estimated value of the internal temperature when disturbance compensation is performed.
FIG. 9 is a diagram showing an operation amount of a main controller and an operation amount of a controller in a disturbance estimation unit.
FIG. 10 is a diagram illustrating a difference between an operation amount of a main controller and an operation amount of a controller in a disturbance estimation unit, and an estimated disturbance.
FIG. 11 is a diagram illustrating a disturbance pattern added to the operation amount of the main controller, an estimation result of the disturbance pattern (estimated disturbance pattern), and a detected value of an internal temperature in a state where the disturbance is added.
FIG. 12 is a diagram showing detected values of internal temperature when disturbance compensation is performed and when disturbance compensation is not performed.
FIG. 13 is a diagram showing a result of confirming, by simulation, robustness of a control system when disturbance compensation is performed.
[Explanation of symbols]
[Explanation of symbols]
1 jacket tank
11 Reaction vessel
12 stirrer
13 jacket
14, 15 temperature detector
21 Temperature control medium inflow pipe
22 Temperature control medium outlet pipe
23 Refrigerant valve
3 Controller
31 Main controller
32 slave controller
33 adder
4 disturbance compensator
41 disturbance estimator
42 Estimated disturbance pattern storage
43 Display / operation unit
44 Disturbance data processing unit
45 Output disturbance pattern storage
46 Estimated disturbance generator
47 FF calculator
48 Driving history storage unit
51 Controller
52 Pseudo-control target
53 adder

Claims (14)

In a process control device that controls a process based on an operation amount output from the control adjustment unit,
The disturbance pattern added to the process based on the difference between the manipulated variable output from the control adjustment unit when the process is performed and the manipulated variable obtained by using the control amount obtained when the process is performed as the target value is calculated. A disturbance estimating unit for estimating,
A storage unit for storing the disturbance pattern estimated by the disturbance estimation unit,
An estimated disturbance output unit that generates a disturbance pattern based on data stored in the storage unit in an operation cycle after the operation cycle in which the disturbance pattern is estimated, and outputs the disturbance pattern as a feedforward operation amount;
Means for adding the feedforward operation amount as a disturbance compensation amount to the operation amount output from the control adjustment unit. The process control device according to claim 1, wherein the disturbance pattern output from the estimated disturbance output unit is a disturbance pattern stored in the storage unit. The process control device according to claim 1, wherein the disturbance pattern output from the estimated disturbance output unit is obtained by performing a predetermined process on the disturbance pattern stored in the storage unit. 4. The process control device according to claim 1, wherein a phase of the disturbance pattern output from the estimated disturbance output unit is ahead of a phase of the disturbance pattern stored in the storage unit. 5. 5. The process control device according to claim 4, wherein the amount of advance of the phase is an amount corresponding to a dead time of a control target controlled by the operation amount. 6. The apparatus according to claim 1, further comprising: means for preparing a plurality of disturbance patterns based on the data stored in the storage unit, and selecting a disturbance pattern to be used from the plurality of disturbance patterns. A process control device according to any one of the above. The disturbance estimating unit receives an operating amount from the estimating adjusting unit using the control amount as a target value and an operation amount from the estimating adjusting unit, and uses a transfer function equivalent to a control target controlled by the operating amount of the control adjusting unit. Means for processing and outputting the input value, and an addition unit for extracting a difference between the operation amount from the control adjustment unit and the operation amount from the estimation adjustment unit as an estimated disturbance,
The process according to any one of claims 1 to 6, wherein the estimation adjustment unit outputs the manipulated variable such that the output value of the transfer function in the disturbance estimation unit matches the set reference trajectory. Control device. The process control device according to claim 7, wherein the transfer function in the disturbance estimating unit does not include a dead time. 9. The process control device according to claim 7, wherein the control regulator and the estimation regulator have the same input / output characteristics. A selection means for selecting one of a mode in which the disturbance is estimated by the disturbance estimation unit while performing the process, and a mode in which the disturbance is estimated by the disturbance estimation unit after the process is completed based on data stored at the time of the process. The process control device according to claim 1, further comprising: The process control device according to any one of claims 1 to 10, further comprising means for displaying a disturbance pattern estimated by the disturbance estimating unit. In a process control method for controlling a process based on an operation amount output from a control adjustment unit,
The disturbance pattern added to the process based on the difference between the manipulated variable output from the control adjustment unit when the process is performed and the manipulated variable obtained by using the control amount obtained when the process is performed as the target value is calculated. Estimating,
Storing the disturbance pattern estimated in this step;
In a driving cycle after the driving cycle in which the disturbance pattern is estimated, a disturbance pattern is generated based on the already stored estimated disturbance pattern, and a step of outputting the disturbance pattern as a feedforward manipulated variable,
Adding the feedforward operation amount as a disturbance compensation amount to the operation amount output from the control adjustment unit. 13. The process control method according to claim 12, wherein in the step of generating a disturbance pattern based on an already stored estimated disturbance pattern, the phase of the estimated disturbance pattern is advanced. In the step of estimating the disturbance pattern, the operation amount from the estimation adjustment unit having the control amount obtained when the process is performed as the target value is transmitted in the same manner as the control target controlled by the operation amount of the control adjustment unit. A step of calculating and outputting by a function, a step of outputting an operation amount from the estimation adjustment unit so that the output value output in this step matches the set reference trajectory,
14. The process control method according to claim 12, further comprising: extracting a difference between the operation amount output in this step and the operation amount of the control adjustment unit.

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