JP2004343925A - Load identifying device, load identifying method, and control system design assisting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a load identifying device, a load identifying method, and a control system design assisting method that makes it possible to easily identify and models load characteristics by a simple structure. <P>SOLUTION: This load identifying device is provided with a current detector 9 that detects a current of a motor, a motor load torque operation part 11 that calculates a motor load value from a current value detected by the current detecting portion 9 and a motor constant, a frequency analyzing portion that analyzes a frequency to the motor load value, a frequency extracting portion 14 that extracts a frequency from the result of the analysis conducted by the frequency analyzing portion, and a time function converter 15 that converts each extracted frequency into a time function. The sum of each calculated time function is identified as a load to be added to the motor. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

（１）式においてＫＴ：モータのトルク定数、Ｉ（ｔ）：モータ電流、ｄＴ（ｔ）：モータ負荷トルク、（ｔ）は時間関数であることを示す。
このときモータ負荷トルクは図８のように検出される。本発明では等速制御を行なっているため、負荷トルクに変動がない場合は、モータ電流は一定となるはずであるが、実際には周波数成分を持っているため図８のようにトルク変動が検出できる。次に、モータ負荷トルクはフィルタ演算部１２において所定のフィルタ処理が行なわれる。
【００１１】
フィルタ演算処理の一例として離散系のＩＩＲフィルタを説明する。サンプリング時間ｔｓで離散化すなわちデータ取得された場合、状態空間方程式（２）と、出力方程式（３）の演算を行うことによって実現できる。
【数２】

【数３】

（２）式及び（３）式においてａｄ、ｂｄ、ｃｄ、ｄｄはｔｓで離散化後のフィルタ定数を表し、ｘ（ｎ）はｎサンプリング時の状態変数、ｕ（ｎ）はｎサンプリング時の入力、ｙ（ｎ）はｎサンプリング時の出力である。
次に、フィルタ処理後のモータ負荷トルク値は、フーリエ解析部１３へ送られ、フーリエ変換が行なわれる。フーリエ変換による解は複素数であるため、各周波数におけるゲインと位相情報は（４）式、（５）式として取得される。
【数４】

【数５】

ここで、Ｒｅは解析結果の実数部、Ｉｍは解析結果の虚数部である。
このときの解析結果は、図９となる。図９の上図がゲイン、下図が位相である。次に、解析結果は周波数抽出部１４に送られ、ゲインが所定値以上となる周波数成分が抽出される。抽出結果は、図１０である。抽出された周波数成分は時間関数変換部１５において、抽出された周波数ごとのゲイン、位相より、余弦関数の形で時間関数に変換される。この抽出された全周波数の余弦関数の和が同定された負荷トルクモデル（数６）となる。同定された負荷トルクモデル（数７）は（６）式として表現される。
【数６】

【数７】

抽出されたｎ＋１個の周波数ω（ｒａｄ／ｓ）と、そのときの位相φ（ｒａｄ）、各周波数におけるトルクの片振幅ｒ（Ｎｍ）、時間ｔ（ｓｅｃ）より（６）式は表されている。なお、添え字ｉはｉ番目の抽出周波数であることを意味する。また、抽出された周波数にはＤＣ成分すなわちω＝０（ｒａｄ／ｓ）の値も含まれる。このように構成された負荷同定装置では、簡単な構成で容易にモータ負荷モデルを同定することができる。
【００１２】
次に、上述した負荷同定装置とは一部異なる構成を採用した場合の負荷同定装置について図２を用いて説明する。なお、測定対象の機構を含む駆動装置とフーリエ解析部１３以降の測定系の構成は上述の負荷同定装置と同一であるため、異なる部分のみ説明する。電流検出部９はホール素子等を使用し被接触である電流センサや電流プローブ、回路中に入れた電流検出抵抗等によって構成される。フィルタ演算部１６とモータ負荷トルク演算部１７はオペアンプ等のアナログ回路で構築される。データ記憶部としての負荷トルク記憶部１８は、データレコーダやディジタルストレージオシロスコープ等の所定サンプリング周波数で所定時間のデータを取得できる計測器、もしくは、Ａ／Ｄ変換器が取付けられ所定サンプリング周波数で所定時間のデータを取得し、記憶できるＰＣ（パーソナルコンピュータ）やＤＳＰボードやＣＰＵボード等の演算装置によって構築される。
フーリエ解析部１３、周波数抽出部１４、時間関数変換部１５は、ＰＣやＤＳＰボードＣＰＵボード等の演算装置によって構築される。また、フィルタ演算部１６から時間関数変換部１５の間の構成をＡ／Ｄ変換器が取付けられ所定サンプリング周波数で所定時間のデータを取得し、記憶できるＰＣ（パーソナルコンピュータ）やＤＳＰボードやＣＰＵボード等の演算装置によって構築し、電流検出部９以外の計測系をディジタル化することも可能である。
動作を説明すると、電流検出部によって検出された電流値は、フィルタ演算部１６で所定のフィルタ処理を施し、モータ負荷トルク演算部１７において（１）式の演算を行ない、電流値をモータ負荷トルクに変換する。モータ負荷トルクは、所定のサンプリング周波数で所定時間分のデータとして、負荷トルク記憶部１８に記憶される。以降、前記装置構成と同様な動作により負荷トルクモデル（数６）は同定される。このように構成された負荷同定装置では、簡単な構成で容易にモータ負荷モデルを同定することができる。
【００１３】
ここで、フィルタ演算部１２，１６について説明する。フィルタ演算部１２，１６ではドライバのスイッチングノイズ、モータのブラシノイズ、回路のノイズ等の負荷同定には不要な高域のノイズカットのため、もしくは同定される負荷の帯域を制限するためにローパスフィルタとして設定される。動作は、上述の（２）、（３）式の演算を行うことによって行われる。ローパスフィルタによって帯域を制限することによって、サンプリング周波数で取得したデータ数を間引くことも可能であり、データの容量を減少させることも可能となる。また、図２の構成である場合、フィルタ演算部１６をアナログ回路で構築することも可能であるため、デジタル演算の負荷を低減することが可能である。このようにフィルタ演算部１２，１６を備えることで、ノイズや不必要な帯域のデータを除去することができる。
【００１４】
次に、時間関数変換部１５で得た時間関数の負荷モデルを位置関数に変換するように構成した場合の負荷同定装置について図３を用いて説明する。なお、図３においてフーリエ解析部１３より前の構成は図１もしくは図２と同様なため、図示は省略する。図３に示すように、時間関数変換部１５で同定された時間関数の負荷トルクモデル（数６）は、位置関数変換部１９において位置と速度を用いた位置関数
【数８】

に変換される。ここでは、検出角度、目標角速度を機構の位置ｘ、速度ｖに変換し、等速であると限定するとｔ＝ｘ／ｖなので、（６）式は（７）式として変換される。
【数９】

（７）式において（ｘ）は位置関数であることを示す。
また、位置関数変換部１９は上述の時間関数変換部１５と同様に、ＰＣ（パーソナルコンピュータ）やＤＳＰボードやＣＰＵボード等の演算装置によって構築される。変換された結果を図１１に示す。この図ではモデル化前の時間関数の負荷トルクｄＴ（ｔ）を位置関数ｄＴ（ｘ）に変換したものもあわせて示してある。このように構成された負荷同定装置では、同定した負荷モデルを制御系設計の支援手段などへ展開しやすい形式に変換することができる。
【００１５】
次に、取得データを記憶する所定時間の長さを、機構部の１回転以上としたときの負荷同定装置について説明する。図１もしくは図２記載の測定対象の機構を含む駆動装置の場合、電流値記憶部１０（図１）、もしくは負荷トルク記憶部１８（図２）においてデータを記憶する時間ｔｌｅｎｇｔｈを、目標角速度をωｒｅｆ（ｒａｄ／ｓ）とすると、（８）式で求まる機構部の１回転に要する時間よりも長くする。これによって、機構部が持つ低周波の負荷成分まで抽出可能となる。
【数１０】

このように構成された負荷同定装置では、機構部が持つ低周波の負荷成分まで抽出することができる。
次に、フィルタ演算部１２，１６のカットオフ周波数をモータ４と機構部５からなる伝達系の機械共振周波数以下としたときの負荷同定装置について説明する。図１のフィルタ演算部１２もしくは図２のフィルタ演算部１６におけるローパスフィルタのカットオフ周波数を、モータ４とベルト６と機構部５からなる伝達系の機械共振周波数よりも低い周波数に設定する。この実施の形態では、機械共振の影響が負荷トルクモデルに現れないようにするため、機械共振周波数ωｍとすると、カットオフ周波数ωＬＰＦを（９）式のように１／５〜１／１０倍とする。
【数１１】
ω_ＬＰＦ ＝ （０．２５〜０．１）×ω_ｍ （９）
このように構成された負荷同定装置では、カットオフ周波数をモータおよび機構系からなる伝達系の機械共振周波数よりも低い周波数に限定するフィルタ演算部を備えることによって、同定した負荷モデルが機械共振周波数以下となるため、同定モデルをモータ軸換算した形で入力可能となり、制御系設計支援上の機構系数学モデルが簡単化できる。
【００１６】
次に、実施の形態としての負荷同定方法について説明する。駆動装置は図１、図２のものと同等である。そして、図１の負荷同定装置と同様に、Ａ／Ｄ変換器を備えたＰＣ（パーソナルコンピュータ）やＤＳＰボードやＣＰＵボード等の演算装置によって所定サンプリング周波数でデータを取得し、負荷トルクモデル（数６）の同定を行う。図１の装置構成と図４のフローチャートで動作を説明すると、等速制御されるときのモータ電流は電流検出部９で検出され、所定サンプリング周波数で所定時間分のデータとして、Ａ／Ｄ変換器より演算装置に取込まれ、電流値記憶工程Ｓ１でＲＡＭやＨＤＤ等に記憶される。電流値記憶工程Ｓ１で蓄えられたデータは、モータ負荷トルク演算工程Ｓ２へ送られ（１）式の演算によってモータ負荷トルクに変換される。
次に、モータ負荷トルクはフィルタ演算工程Ｓ３において所定のフィルタ処理が行なわれる。高域のノイズカットと測定帯域の制限を目的とするローパスフィルタ処理である。フィルタ演算処理がＩＩＲフィルタである場合、状態空間方程式（２）式と、出力方程式（３）式の演算を行うことによって実現できる。次に、フィルタ処理後のモータ負荷トルク値は、フーリエ解析工程Ｓ４へ送られ、フーリエ変換が行なわれる。次に、解析結果は周波数抽出工程Ｓ５に送られ、ゲインが所定値以上となる周波数成分が抽出される。抽出された周波数成分は時間関数変換工程Ｓ６において、抽出された周波数ごとのゲイン、位相より、余弦関数の形で時間関数に変換される。この抽出された全周波数の余弦関数の和が同定された負荷トルクモデルとなる。同定された負荷トルクモデル（数６）は（６）式として表現される。このように構成された負荷同定方法では、簡単な手法で容易にモータ負荷トルクモデルを同定することができる。
【００１７】
次に、負荷同定装置を図２の構成とした場合の負荷同定方法について説明する。駆動装置は図１、図２のものと同等である。そして、図２の負荷同定装置と同様に、検出された電流値からモータ負荷トルクに換算するアナログ演算部を備え、Ａ／Ｄ変換器を備えたＰＣ（パーソナルコンピュータ）やＤＳＰボードやＣＰＵボード等の演算装置によって所定サンプリング周波数でデータを取得し、負荷トルクモデルの同定を行う。図２の装置構成と図５のフローチャートで動作を説明すると、等速制御されるときのモータ電流は電流検出部９で検出される。検出された電流値は、アナログ演算部のフィルタ演算工程Ｓ７で所定のフィルタ処理が行なわれる。高域のノイズカットと測定帯域の制限を目的とするローパスフィルタ処理である。
次に、モータ負荷トルク演算工程Ｓ８へ送られ（１）式の演算によってモータ負荷トルクに変換される。モータ負荷トルクは電圧信号であるため所定サンプリング周波数でＡ／Ｄ変換器より演算装置に取込まれ、負荷トルク記憶工程Ｓ９でＲＡＭやＨＤＤ等に記憶される。Ｓ１０においてデータが所定時間分取得されたか判断する。データ取得が完了していない場合は、負荷トルク記憶工程Ｓ９へ戻りＡ／Ｄ変換器よりデータを取得し記憶する。Ｓ１０においてデータ取得が完了したと判断した場合、フーリエ解析Ｓ４へ進む、以下の動作は図４のＳ４以下の動作と同一である。このように構成された負荷同定方法では、簡単な手法で容易にモータ負荷トルクモデルを同定することができる。
ところで、図４のフィルタ演算工程Ｓ３もしくは図５のフィルタ演算工程Ｓ７ではドライバのスイッチングノイズ、モータのブラシノイズ、回路のノイズ等の負荷同定には不要な高域のノイズカットのため、もしくは同定される負荷の帯域を制限するためにローパスフィルタとしての設定が施されている。動作は、図４のフィルタ演算工程Ｓ３もしくは図５のフィルタ演算工程Ｓ７において、上述の（２）式、（３）式の演算を行うことによって行われる。ローパスフィルタによって帯域を制限することによって、サンプリング周波数で取得したデータ数を間引くことも可能であり、データの容量を減少させることも可能となる。このようにフィルタ演算工程Ｓ３、Ｓ７を備えることで、ノイズや不必要な帯域のデータを除去することができる。
【００１８】
次に、同定された時間関数の負荷を位置と速度によって、位置関数の負荷とする位置関数変換工程を備えた場合の負荷同定方法について図６のフローチャートを用いて説明する。なお、図６の時間関数変換工程Ｓ６以前の工程は図４もしくは図５の時間関数変換工程Ｓ６以前の工程と同様なため、その説明は省略する。図４もしくは図５の負荷同定方法で同定された時間関数の負荷トルクモデル（数６）は、位置関数変換工程Ｓ１１において位置と速度を用いた位置関数（数８）に変換される。位置関数変換工程Ｓ１１では（６）式を（７）式へ変換する処理が行われる。このように構成された負荷同定方法では、同定した負荷トルクモデルを制御系設計の支援手段などへ展開しやすい形式に変換することができる。
次に、取得データを記憶する所定時間の長さを、機構部の１回転以上としたときの負荷同定方法について説明する。図１もしくは図２の駆動装置の場合、図４の負荷同定方法における電流値記憶工程Ｓ１、もしくは図５の負荷同定方法における負荷トルク記憶工程Ｓ９においてデータを記憶する時間ｔｌｅｎｇｔｈを、目標角速度をωｒｅｆ（ｒａｄ／ｓ）とすると、（８）式で求まる機構部の１回転に要する時間よりも長くする。このように構成された負荷同定方法では、機構部が持つ低周波の負荷成分まで抽出することができる。
【００１９】
次に、図４のフィルタ演算工程Ｓ３もしくは図５のフィルタ演算工程Ｓ７におけるカットオフ周波数をモータ４とベルト６と機構部５からなる伝達系の機械共振周波数よりも低い周波数に設定した場合の負荷同定方法について説明する。こここでは、機械共振の影響が負荷トルクモデルに現れないようにするため、機械共振周波数ωｍとすると、カットオフ周波数ωＬＰＦを１／５〜１／１０倍とする。（９）式のフィルタ演算を図４のフィルタ演算工程Ｓ３、もしくは図５のフィルタ演算工程Ｓ７で行う。このように構成された負荷同定方法では、カットオフ周波数をモータおよび機構系からなる伝達系の機械共振周波数よりも低い周波数に限定するフィルタ演算工程とすることによって、同定した負荷モデルが機械共振周波数以下となるため、同定モデルをモータ軸換算した形で入力可能となり、制御系設計支援上の機構系数学モデルが簡単化できる。
なお、上述した負荷同定装置及び負荷同定方法では、負荷同定装置および負荷同定方法単体に限定して構成・動作を説明しているが、これら負荷同定装置及び負荷同定方法を実際の装置、例えば、ステージ制御装置、ロボット、複写機、プリンタの駆動機構等に組み込み、起動直後などの所定のタイミングで負荷同定を行い、同定された負荷が設計時に想定されている負荷よりも大きい場合は、装置異常とする装置異常判別や、同定された負荷による制御パラメータ変更手段に使用することが可能である。
【００２０】
次に、実施の形態としての制御系設計支援方法について説明する。この制御系設計支援方法は数学モデルにおけるモータの回転角度もしくは位置、機構部の回転角度もしくは位置のいずれか一つによって、外乱が変化するようにした場合である。図１もしくは図２で説明した測定対象の機構を含む駆動装置は図７に示されるような制御系設計支援方法の速度制御系数学モデルとして演算装置上で構築される。モータと機構部からなる数学モデル２３は電流値が入力され機構部の回転角度を出力する。出力された回転角度は、速度演算部モデル２４へ入力され角速度信号が出力される。角速度信号は、目標角速度モデル２０と比較され速度偏差が算出される。この速度偏差は、速度制御コントローラモデルである補償器モデル２１に入力される。
補償器モデル２１では、速度偏差に位相補償等を行ない操作量である電流指令値を出力する。出力された電流指令値はモータドライバモデル２２へ入力される。モータドライバモデル２２は、前記電流指令値に応じてモータと機構部からなる数学モデル２３へ電流を流す。このような速度制御系数学モデルを使用し、速度制御の応答シミュレーションを行う。この速度制御系数学モデルに、上述の負荷同定装置および負荷同定方法で同定され、（７）式で表される位置関数の負荷トルクモデル（数６）を反映する。位置関数の負荷トルクモデル（数６）２５へ機構部の位置が入力される。ここでは、機構部の出力は回転角度であるが、（７）式に合わせて位置へ変換して入力される。位置関数の負荷トルクモデル（数６）２５は位置に応じた負荷トルクを出力する。出力された負荷トルクを電流変換部２６で負荷トルク相当の電流値Ｉｄ（ｘ）に変換し、電流値の形で比較器２７により速度制御系数学モデルに印加する。
電流変換部２６では（１０）式によって変換を行なう。
【数１２】

ここでは、簡単化のためモータと機構部を一体のモデルとして考え、負荷トルクを負荷トルク相当の電流値に変換して印加したが、モータと機構部が分割されたモデルである場合、モータ出力トルクへ負荷トルクを印加するモデルとしても良い。このように構成された制御系設計支援方法では、比較的低い領域の負荷特性抽出に注力し同定した負荷モデルをモータへ加わる負荷外乱とし、数学モデルの位置情報によって負荷を変動させることができる。
【００２１】
次に、あらかじめ数学モデルのモータの回転角度もしくは位置、機構部の回転角度もしくは位置のいずれか一つに対応する負荷データテーブルを作成し、これを数学モデルのモータに加わる外乱モデルとし、数学モデルのモータの回転角度もしくは位置、機構部の回転角度もしくは位置のいずれか一つによって負荷データテーブルの値を選択することによって外乱が変化するようにした場合の制御系設計支援方法について説明する。この制御系設計支援方法では、同定された（７）式の負荷トルクモデル（数６）をあらかじめ計算し、位置データと負荷トルクデータを対応させた負荷トルクデータテーブルとして用意する。その負荷トルクデータテーブルを請求項１１の負荷トルクモデル（数６）２５として使用し、入力される位置に応じた負荷トルクを出力する。このように構成された制御系設計支援方法では、負荷モデルをデータテーブル化しているので、負荷トルクモデル（数６）２５における（７）式の演算が不要となるためシミュレーションの演算負荷を低減することができる。
【００２２】
次に、図１、図２の負荷同定装置もしくは図４、図５の負荷同定方法で求めた周波数成分ごとの時間関数の負荷を数学モデルのモータに加わる外乱モデルとし、数学モデルの時間変化に応じて、外乱が変化するようにした場合の制御系設計支援方法について図１２を用いて説明する。図１もしくは図２で説明した測定対象の機構を含む駆動装置は図１２に示されるような制御系設計支援方法の速度制御系数学モデルとして演算装置上で構築される。モータと機構部からなる数学モデル２３は電流値が入力され機構部の回転角度を出力する。出力された回転角度は、速度演算部モデル２４へ入力され角速度信号が出力される。角速度信号は、目標角速度モデル２０と比較され速度偏差が算出される。速度偏差は、速度制御コントローラモデルである補償器モデル２１に入力される。
補償器モデル２１では、速度偏差に位相補償等を行ない操作量である電流指令値を出力する。出力された電流指令値はモータドライバモデル２２へ入力される。モータドライバモデル２２は、電流指令値に応じてモータと機構部からなる数学モデル２３へ電流を流す。このような速度制御系数学モデルを使用し、速度制御の応答シミュレーションを行なう。この速度制御系数学モデルに、上述の負荷同定装置および負荷同定方法で同定され、（６）式で表される時間関数の負荷トルクモデル（数６）を反映する。時間関数の負荷トルクモデル（数６）２９へシミュレーションの時間２８が入力される。時間関数の負荷トルクモデル（数６）２９はシミュレーション時間に応じた負荷トルクを出力する。出力された負荷トルクを電流変換部２６で負荷トルク相当の電流値Ｉｄ（ｘ）に変換し、電流値の形で比較器２７により前記速度制御系数学モデルに印加する。電流変換部２６では前記（１０）式によって変換を行なう。
このように構成された制御系設計支援方法では、比較的低い領域の負荷特性抽出に注力し同定した負荷モデルをモータへ加わる負荷外乱とし、数学モデルの時間情報によって負荷を変動させることができる。なお、ここでは、簡単化のためモータと機構部を一体のモデルとして考え、負荷トルクを負荷トルク相当の電流値に変換して印加したが、モータと機構部が分割されたモデルである場合、モータ出力トルクへ負荷トルクを印加するモデルとしても良い。
【００２３】
次に、図３の負荷同定装置もしくは図８の負荷同定方法で求めた周波数成分ごとの時間関数の負荷を使用し、あらかじめ時間に対応する負荷データテーブルを作成し、これを数学モデルのモータに加わる外乱モデルとし、数学モデルの時間変化によって負荷データテーブルの値を選択することによって外乱が変化するようにした場合の制御系設計支援方法について説明する。この制御系設計支援方法では、同定された（６）式の負荷トルクモデル（数６）をあらかじめ計算し、時間データと負荷トルクデータを対応させた負荷トルクデータテーブルとして用意する。その負荷トルクデータテーブルを図１２の負荷トルクモデル（数６）２９として使用し、入力されるシミュレーション時間２８に応じた負荷トルクを出力する。このように構成された制御系設計支援方法では、負荷モデルをデータテーブル化したので、負荷トルクモデル（数６）２９における（６）式の演算が不要となるためシミュレーションの演算負荷を低減することができる。
なお、ここで示した実施の形態としての負荷同定装置、負荷同定方法、制御系設計支援方法では、回転モータを使用した駆動装置に基づいて説明したが、モータをリニアモータとした場合は、モータ軸に加わる負荷トルクではなくリニアモータの可動子に加わる負荷力とし、回転角度・角回転数を位置・速度として対応させることによって適用できる。
【００２４】
【発明の効果】
以上説明したように、請求項１によれば、モータ負荷値に対して周波数解析を行う周波数解析部と、周波数解析部が解析した結果より周波数を抽出する周波数抽出部と、抽出した周波数ごとに時間関数に変換する時間関数変換部とを備え、算出された各時間関数の和をモータに加わる負荷として同定するようにしたので、機構の構成に関係無く、簡単な構成で容易にモータ負荷モデルを同定できる負荷同定装置を提供することができる。
請求項２によれば、同定する負荷の帯域を制限するフィルタ演算部を備えているので、ノイズや不必要な帯域のデータを除去可能な負荷同定装置を提供することができる。
請求項３によれば、同定された時間関数の負荷を位置と速度によって、位置関数の負荷とする位置関数変換部を備えているので、同定した負荷モデルを制御系設計の支援手段などへ展開しやすい形式に変換できる負荷同定装置を提供することができる。
請求項４によれば、データ記憶部において取得データを記憶する所定時間の長さを、機構部の１回転以上もしくは、１走査以上の時間とするようにしたので、機構部が持つ低周波の負荷成分まで抽出可能な負荷同定装置を提供することができる。
請求項５によれば、カットオフ周波数をモータおよび機構系からなる伝達系の機械共振周波数よりも低い周波数に限定するフィルタ演算部を備えることによって、同定した負荷モデルが前記機械共振周波数以下となるため、同定モデルをモータ軸換算した形で入力可能となり、制御系設計支援上の機構系数学モデルが簡単化できる負荷同定装置を提供することができる。
請求項６によれば、モータ負荷値に対して周波数解析を行う周波数解析工程と、周波数解析部が解析した結果より周波数を抽出する周波数抽出工程と、抽出した周波数ごとに時間関数に変換する時間関数変換工程とを備え、算出された各時間関数の和をモータに加わる負荷として同定するようにしたので、機構の構成に関係無く、簡単な手法で容易にモータ負荷トルクモデル（数６）を同定することができる負荷同定方法を提供することができる。
【００２５】
請求項７によれば、同定する負荷の帯域を制限するフィルタ演算工程を備えているので、ノイズや不必要な帯域のデータを除去可能な負荷同定方法を提供することができる。
請求項８によれば、同定された時間関数の負荷を位置と速度によって、位置関数の負荷とする位置関数変換工程を備えているので、同定した負荷モデルを制御系設計の支援手段などへ展開しやすい形式に変換できる負荷同定方法を提供することができる。
請求項９によれば、データ記憶工程において取得データを記憶する所定時間の長さを、機構部の１回転以上もしくは、１走査以上の時間とするようにしたので、機構部が持つ低周波の負荷成分まで抽出可能な負荷同定装置を提供することができる。
請求項１０によれば、カットオフ周波数をモータおよび機構系からなる伝達系の機械共振周波数よりも低い周波数に限定するフィルタ演算工程とすることによって、同定した負荷モデルが前記機械共振周波数以下となるため、同定モデルをモータ軸換算した形で入力可能となり、制御系設計支援上の機構系数学モデルが簡単化できる負荷同定方法を提供することができる。
請求項１１によれば、比較的低い領域の負荷特性抽出に注力し同定した負荷モデルをモータへ加わる負荷外乱とし、数学モデルの位置情報によって負荷を変動させることが可能な設計支援方法を提供することができる。
請求項１２によれば、負荷モデルをデータテーブル化し、機構部の回転角度もしくは位置によってデータテーブルの値を選択することによって演算負荷を低減可能な設計支援方法を提供することができる。
請求項１３によれば、比較的低い領域の負荷特性抽出に注力し同定した負荷モデルをモータへ加わる負荷外乱とし、数学モデルの時間情報によって負荷を変動させることが可能な設計支援方法を提供することができる。
請求項１４によれば、時間関数の負荷を使用し、負荷モデルをデータテーブル化することによって演算負荷を低減可能な設計支援方法を提供することができる。
【図面の簡単な説明】
【図１】負荷同定装置の構成を示す図である。
【図２】図１の負荷同定装置とは一部異なる構成を採用した場合の負荷同定装置を示す図である。
【図３】時間関数の負荷モデルを位置関数に変換するように構成した場合の負荷同定装置を示す図である。
【図４】負荷同定方法（図１の負荷同定装置を用いて説明した場合）を示す図である。
【図５】負荷同定方法（図２の負荷同定装置を用いて説明した場合）を示す図である。
【図６】位置関数変換工程を備えた場合の負荷同定方法を説明する図である。
【図７】数学モデルにおけるモータの回転角度もしくは位置、機構部の回転角度もしくは位置のいずれか一つによって、外乱が変化するようにした場合の制御系設計支援方法を説明する図である。
【図８】検出されたモータ負荷トルクを示す図である。
【図９】解析結果を示す図である。
【図１０】抽出結果を示す図である。
【図１１】変換結果を示す図である。
【図１２】周波数成分ごとの時間関数の負荷を数学モデルのモータに加わる外乱モデルとし、数学モデルの時間変化に応じて、外乱が変化するようにした場合の制御系設計支援方法を説明する図である。
【符号の説明】
１ 目標角速度、２ 補償器、３ モータドライバ、４ モータ、５ 機構部、６ ベルト、７ エンコーダ、８ 速度演算部、９ 電流検出部、１０ 電流値記憶部、１１，１７ モータ負荷トルク演算部、１２，１６ フィルタ演算部、１３ フーリエ解析部、１４ 周波数抽出部、１５ 時間関数変換部、１８ 負荷トルク記憶部、１９ 位置関数変換部、２０ 目標角速度モデル、２１ 補償器モデル、２２ モータドライバモデル、２３ 数学モデル、２４ 速度演算部モデル、２５ 負荷トルクモデル、２６ 電流変換部、２７ 比較器、２８ 時間、２９ 負荷トルクモデル[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a load identification device, a load identification method, and a control system design support method suitable for application to general control system design simulation, load measurement of a drive system such as a photosensitive drum drive unit of a copying machine, and the like.
[0002]
[Prior art]
In designing a control system having a drive unit, a model of a load characteristic or the like derived in advance may be used. For example, in a motor load characteristic identification device disclosed in Japanese Patent Application Laid-Open No. 8-220197, a motor torque is detected from a motor current, a transfer function from the motor torque to the motor speed is identified from the motor torque and the motor speed, and various types of two inertia systems are identified. Techniques for a device for identifying a parameter and a device for adjusting a control parameter of a motor control device based on the identification result are disclosed. Japanese Patent Application Laid-Open No. 11-182638 discloses a design support method for a mechanism for driving a cylindrical rotating body via a belt in a transmission belt design supporting method for a cylindrical rotating body drive system. The disturbance torque and friction load are obtained from the torque and the moment of inertia.
[Patent Document 1] JP-A-8-220197
[Patent Document 2] JP-A-11-182638
[0003]
[Problems to be solved by the invention]
By the way, in the motor load characteristic identification device of Patent Document 1, the mechanism system is limited to a two-inertia system, and the least square method is used so that the error between the transfer function of the two-inertia model and the response of the actual machine is minimized. The transfer function parameters are calculated. Further, the parameters of the mechanical system to be identified are treated as unknown before the identification. This technique identifies a parameter of a mechanical system expressed by a transfer function of two inertia. In the embodiment, there is a description about load torque in which the load torque is modeled as a time function, but no specific modeling method of the load torque is described. Therefore, this method cannot completely separate the parameters of the mechanical system and the load torque, and if the mechanical system is eccentric, the fluctuation of the load torque may be identified as a parameter of the transfer function. May contain errors. Further, the transmission belt design support method of the cylindrical rotating body drive system of Patent Document 2 is a method used for design support (simulation analysis) based on mechanism design data, and does not reflect the load characteristics of the actual machine in the design support. . Further, in actual machines, there are load characteristics that are difficult to model other than disturbance torque and frictional load considered in the mathematical model. In order to perform simulation analysis, it is necessary to design a mathematical model. Assuming that the mathematical model is constructed from a mechanism model, a control system model, and a load characteristic model, the design of the mechanism model and the control system model is relatively easy. For example, as a method of designing a mechanism model, a method based on mechanism design data, such as a transmission belt design support method for a cylindrical rotating body drive system of Patent Document 2, or a method of modeling from a frequency response analysis result of an actual machine Etc. However, it is not easy to model the load characteristics by the method in the transmission belt design support method of the cylindrical rotating body drive system of Patent Document 2.
[0004]
For example, in the case of a rotating body, if the load characteristics change according to the rotation angle, it appears as a variation in the positioning time. In a simulation analysis in which such a variation in positioning time is a problem and a tendency of response that is a problem, and a high-precision analysis is not required, a load characteristic model of the manufactured actual machine can be easily obtained. , There is a demand that it be reflected in the analysis. In the load characteristics of a mechanical system such as a general positioning device, the part that greatly affects the positioning accuracy is in the low frequency range.Therefore, it is necessary to analyze the complex transfer characteristics and model up to the high frequency range. On the other hand, it is over-specification, which increases labor and calculation load.
Therefore, the present invention has been made to solve the above problems, and a load identification device, a load identification method, and a control system design support method capable of easily identifying and modeling load characteristics with a simple configuration. The purpose is to provide.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, in the invention according to claim 1, a motor, a mechanism driven by the motor, a rotation angle or position of the motor, and a rotation angle or position of the mechanism are detected. A drive comprising at least one of the position detecting means, a speed calculating means for calculating a speed signal, and a control section for driving the motor or the mechanism section at a predetermined speed or angular speed using the speed signal. A load identification device for identifying a load model applied to the motor, wherein the current detection unit detects a current of the motor; and a motor load value is calculated from a current value and a motor constant detected by the current detection unit. A motor load calculation unit, a frequency analysis unit that performs frequency analysis on the motor load value, and a frequency extracted from a result analyzed by the frequency analysis unit. A frequency extraction unit, and a time function conversion unit that converts each extracted frequency into a time function, and a load identification device that identifies the sum of the calculated time functions as a load applied to the motor as the most important features. I do.
The invention according to claim 2 is characterized mainly by a load identification device including a filter operation unit for limiting a band of a load to be identified.
The invention according to claim 3 is characterized mainly by a load identification device including a position function conversion unit that uses the identified load of the time function as the load of the position function based on the position and speed.
According to a fourth aspect of the present invention, there is provided a load identification device including a data storage unit having a data storage unit for setting a length of a predetermined time for storing acquired data to be one rotation or more of the mechanism unit or one scan or more. I do.
The invention according to claim 5 is characterized mainly by a load identification device in which a cutoff frequency of the filter operation unit is set to be equal to or lower than a mechanical resonance frequency of a transmission system including the motor and the mechanical unit.
[0006]
In the invention according to claim 6, at least one of a motor, a mechanism driven by the motor, and a rotation angle or position of the motor, or a position detection unit that detects a rotation angle or position of the mechanism is provided. And a speed calculating means for calculating a speed signal, and a control unit for driving the motor or the mechanical unit at a predetermined speed or an angular speed using the speed signal, wherein a load model applied to the motor is A load identification method for identifying, comprising: a motor load calculation step of calculating a motor load value from a current value and a motor constant detected by a current detection unit that detects a current of the motor; and performing a frequency analysis on the motor load value. Performing a frequency analysis step, extracting a frequency component from a result analyzed by the frequency analysis unit, and By the time function conversion step of converting the time function every, load identification method of identifying a sum of the time function calculated as a load applied to the motor and main features.
The invention according to claim 7 is characterized mainly by a load identification method including a filter operation step of limiting a band of a load to be identified.
The invention according to claim 8 is characterized mainly by a load identification method including a position function conversion step in which the load of the identified time function is used as the load of the position function by the position and the speed.
According to a ninth aspect of the present invention, a load identification method includes a data storage step of setting the length of a predetermined time for storing acquired data to be one or more rotations of the mechanism unit or one or more scans. I do.
The main feature of the invention according to claim 10 is a load identification method in which a cutoff frequency in the filter calculation step is set to be equal to or lower than a mechanical resonance frequency of a transmission system including the motor and the mechanism.
[0007]
According to the eleventh aspect, at least one of a motor, a mechanism driven by the motor, and a rotation angle or position of the motor, or a position detection unit configured to detect a rotation angle or position of the mechanism may be used. A drive device comprising a speed calculation means for calculating a speed signal, and a control unit for driving the motor or the mechanism at a predetermined speed or angular speed using the speed signal as a mathematical model, In a control system design support method for analyzing a response of a drive device, a load of a position function for each frequency component obtained by the load identification device according to claim 3 or the load identification method according to claim 8 is applied to the motor of the mathematical model. As the disturbance model to be added, the rotation angle or position of the motor or the rotation angle or position of the mechanism in the mathematical model By one or Re, the control system design support method as disturbance varies mainly characterized.
According to the twelfth aspect of the present invention, at least one of a motor, a mechanism driven by the motor, and a rotation angle or position of the motor, or a position detection unit configured to detect a rotation angle or position of the mechanism may be used. A drive device comprising a speed calculation means for calculating a speed signal, and a control unit for driving the motor or the mechanism at a predetermined speed or angular speed using the speed signal as a mathematical model, In a control system design support method for analyzing the response of a driving device, the load of a position function for each frequency component obtained by the load identification device according to claim 3 or the load identification method according to claim 8 is used, and the mathematical model is previously determined. Load data corresponding to any one of the rotation angle or position of the motor and the rotation angle or position of the mechanism unit. Table, this is used as a disturbance model applied to the motor of the mathematical model, and the rotational angle or position of the motor of the mathematical model, or the rotational angle or position of the mechanism unit, is used to generate the load data table. The main feature is a control system design support method in which a disturbance is changed by selecting a value.
[0008]
According to a thirteenth aspect of the present invention, at least one of a motor, a mechanism driven by the motor, and a rotation angle or position of the motor, or position detection means for detecting a rotation angle or position of the mechanism is provided. A drive device comprising a speed calculation means for calculating a speed signal, and a control unit for driving the motor or the mechanism at a predetermined speed or angular speed using the speed signal as a mathematical model, In a control system design support method for analyzing a response of a driving device, a load of a time function for each frequency component obtained by the load identification device according to claim 1 or the load identification method according to claim 6 is applied to the motor of the mathematical model. The main feature is a control system design support method in which a disturbance model is added so that the disturbance changes according to the time change of the mathematical model. To.
In the invention according to claim 14, at least one of a motor, a mechanism driven by the motor, and a rotation angle or position of the motor, or a position detection unit that detects a rotation angle or position of the mechanism is provided. A drive device comprising a speed calculation means for calculating a speed signal, and a control unit for driving the motor or the mechanism at a predetermined speed or angular speed using the speed signal as a mathematical model, In a control system design support method for analyzing a response of a drive device, a load of a time function for each frequency component obtained by the load identification device according to claim 3 or the load identification method according to claim 8 is used to correspond to time in advance. A load data table is created, and this is used as a disturbance model applied to the motor of the mathematical model. And key features of the control system design support method as disturbance is varied by selecting the value of the load data table by reduction.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a load identification device, a load identification method, and a control system design support method according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a configuration of a load identification device as an embodiment. The load identification device is roughly divided into two parts. One is a drive device including a mechanism to be measured, and the other is a measurement system. As the driving device, an example will be described in which a mechanical unit 5 is a two-inertia system driven by a motor 4 via a belt 6 and measures a load torque. It is used in many devices and devices such as a drive system for a photosensitive drum of a copying machine. In the case of controlling the speed of the above-described mechanism, it is common to detect the rotation angle of a motor or a mechanism by an encoder, calculate the speed from the value, and perform feedback control.
In this driving device, an encoder 7 is mounted as a position detecting means for detecting a rotation angle on the same axis as the rotation axis of the mechanism section 5, an output of the encoder 7 is input to a speed calculating section 8 as speed calculating means, and a speed signal is input. obtain. Here, since it is a rotating system, the speed signal is an angular speed signal. The speed calculating unit 8 counts the encoder pulse interval with the reference clock, or counts the number of pulses entering during the reference calculation cycle and calculates the difference from the number of pulses one sample before, thereby obtaining the speed signal. Is calculated. The calculated angular velocity signal and the target angular velocity 1 are compared to calculate a velocity deviation. The speed deviation is input to a compensator 2 which is a control unit (speed control controller). The compensator 2 performs a phase compensation or the like on the speed deviation and outputs a current command value which is an operation amount. The output current command value is input to the motor driver 3. The motor driver 3 supplies a current to the motor according to the current command value. The mechanism section is controlled at a constant speed by such a speed feedback system. Although the motor driver 3 can be constructed with a voltage-driven amplifier, it is assumed here that a current-controlled amplifier is used as the motor driver 3 in order to improve and simplify the performance of the control system.
[0010]
Next, the configuration of the measurement system will be described. The current detection unit 9 is constructed by using a Hall element or the like and a current sensor or a current probe to be contacted, a current detection resistor inserted in a circuit, or the like. In this example, a current value storage unit 10 is provided as a data storage unit for storing a detected current, and the current value storage unit 10 can acquire data for a predetermined time at a predetermined sampling frequency such as a data recorder or a digital storage oscilloscope. A measuring instrument or an A / D converter is attached, and is constructed by a computing device such as a PC (personal computer), a DSP board, or a CPU board capable of acquiring and storing data for a predetermined time at a predetermined sampling frequency. At present, since the arithmetic processing system is generally digitally processed, a motor load torque calculating unit 11, a filter calculating unit 12, a Fourier analyzing unit 13, a frequency extracting unit 14, a time function converting unit as a motor load calculating unit in the drawing are shown. Reference numeral 15 is constructed by an arithmetic unit such as a PC including a frequency analysis unit and a DSP board CPU board.
Next, the operation of the measurement system will be described. The motor current at the time of constant speed control is detected by the current detection unit 9 and stored in the current value storage unit 10 as data for a predetermined time at a predetermined sampling frequency. The predetermined sampling frequency and the predetermined time vary depending on the frequency band to be analyzed and the resolution. It is necessary to set the sampling frequency to at least twice the frequency band to be analyzed. The data stored in the current value storage unit 10 is sent to the motor load torque calculation unit 11 and is converted into the motor load torque by the calculation of equation (1). Equation (1) holds because the motor torque is proportional to the current value.
(Equation 1)

In equation (1), KT: motor torque constant, I (t): motor current, dT (t): motor load torque, and (t) indicate a time function.
At this time, the motor load torque is detected as shown in FIG. In the present invention, since the constant speed control is performed, the motor current should be constant when the load torque does not fluctuate. However, since the motor current actually has a frequency component, the torque fluctuates as shown in FIG. Can be detected. Next, a predetermined filter process is performed on the motor load torque in the filter calculation unit 12.
[0011]
A discrete IIR filter will be described as an example of the filter operation processing. When the data is discretized at the sampling time ts, that is, data is acquired, it can be realized by calculating the state space equation (2) and the output equation (3).
(Equation 2)

[Equation 3]

In equations (2) and (3), ad, bd, cd, and dd represent filter constants after discretization with ts, x (n) is a state variable at the time of n sampling, and u (n) is a state variable at the time of n sampling. The input, y (n), is the output at the time of n sampling.
Next, the motor load torque value after the filter processing is sent to the Fourier analysis unit 13, where the Fourier transform is performed. Since the solution by the Fourier transform is a complex number, the gain and phase information at each frequency are obtained as Expressions (4) and (5).
(Equation 4)

(Equation 5)

Here, Re is the real part of the analysis result, and Im is the imaginary part of the analysis result.
The analysis result at this time is shown in FIG. The upper diagram in FIG. 9 shows the gain, and the lower diagram shows the phase. Next, the analysis result is sent to the frequency extracting unit 14, and a frequency component whose gain is equal to or more than a predetermined value is extracted. FIG. 10 shows the extraction result. The extracted frequency component is converted to a time function in the form of a cosine function from the gain and phase for each extracted frequency in the time function conversion unit 15. The sum of the extracted cosine functions of all the frequencies is the identified load torque model (Equation 6). The identified load torque model (Equation 7) is expressed as Expression (6).
(Equation 6)

(Equation 7)

Expression (6) is expressed by the extracted n + 1 frequencies ω (rad / s), the phase φ (rad) at that time, the one-sided amplitude r (Nm) of the torque at each frequency, and the time t (sec). I have. Note that the subscript i means the i-th extracted frequency. Further, the extracted frequency includes a DC component, that is, a value of ω = 0 (rad / s). The load identification device configured as described above can easily identify a motor load model with a simple configuration.
[0012]
Next, a description will be given of a load identification device employing a configuration partially different from the above-described load identification device with reference to FIG. Note that the configuration of the drive system including the mechanism to be measured and the measurement system after the Fourier analysis unit 13 are the same as those of the above-described load identification device, and therefore only different parts will be described. The current detecting section 9 uses a Hall element or the like and includes a current sensor or current probe to be contacted, a current detecting resistor inserted in a circuit, and the like. The filter operation unit 16 and the motor load torque operation unit 17 are constructed by analog circuits such as operational amplifiers. The load torque storage unit 18 as a data storage unit is a measuring device such as a data recorder or a digital storage oscilloscope that can acquire data for a predetermined time at a predetermined sampling frequency, or an A / D converter is attached and a predetermined time for a predetermined time at a predetermined sampling frequency. It is constructed by an arithmetic device such as a PC (personal computer) or a DSP board or a CPU board capable of acquiring and storing the data.
The Fourier analysis unit 13, the frequency extraction unit 14, and the time function conversion unit 15 are constructed by an arithmetic device such as a PC or a DSP board CPU board. Also, a configuration between the filter operation unit 16 and the time function conversion unit 15 is a PC (personal computer), a DSP board, or a CPU board, which is provided with an A / D converter and can acquire and store data for a predetermined time at a predetermined sampling frequency. It is also possible to digitize the measurement system other than the current detection unit 9 by using an arithmetic device such as the above.
In operation, the current value detected by the current detection unit is subjected to a predetermined filtering process in a filter calculation unit 16, the calculation of Expression (1) is performed in a motor load torque calculation unit 17, and the current value is converted to the motor load torque. Convert to The motor load torque is stored in the load torque storage unit 18 as data for a predetermined time at a predetermined sampling frequency. Thereafter, the load torque model (Equation 6) is identified by the same operation as the above-described device configuration. The load identification device configured as described above can easily identify a motor load model with a simple configuration.
[0013]
Here, the filter operation units 12 and 16 will be described. The filter operation units 12 and 16 are low-pass filters for cutting high-frequency noise unnecessary for load identification such as driver switching noise, motor brush noise, and circuit noise, or for limiting the band of the load to be identified. Is set as The operation is performed by performing the calculations of the above equations (2) and (3). By limiting the band by the low-pass filter, the number of data acquired at the sampling frequency can be reduced, and the data capacity can be reduced. In addition, in the case of the configuration of FIG. 2, the filter operation unit 16 can be configured by an analog circuit, so that the load of digital operation can be reduced. By providing the filter operation units 12 and 16 in this manner, noise and unnecessary band data can be removed.
[0014]
Next, a load identification device configured to convert the load model of the time function obtained by the time function conversion unit 15 into a position function will be described with reference to FIG. Note that the configuration before the Fourier analysis unit 13 in FIG. 3 is the same as that in FIG. 1 or FIG. As shown in FIG. 3, the load torque model (Equation 6) of the time function identified by the time function conversion unit 15 is a position function using the position and the speed in the position function conversion unit 19.
(Equation 8)

Is converted to Here, the detected angle and the target angular velocity are converted into the position x and the velocity v of the mechanism, and if it is limited to a constant velocity, since t = x / v, the equation (6) is converted into the equation (7).
(Equation 9)

In equation (7), (x) indicates a position function.
Further, the position function conversion unit 19 is constructed by an arithmetic device such as a PC (personal computer), a DSP board, or a CPU board, like the time function conversion unit 15 described above. FIG. 11 shows the result of the conversion. This figure also shows the result obtained by converting the load torque dT (t) of the time function before modeling into the position function dT (x). With the load identification device configured as described above, the identified load model can be converted into a format that can be easily developed into control system design support means or the like.
[0015]
Next, a description will be given of the load identification device when the length of the predetermined time for storing the acquired data is one rotation or more of the mechanical unit. In the case of the drive device including the mechanism to be measured shown in FIG. 1 or FIG. 2, the time length for storing data in the current value storage unit 10 (FIG. 1) or the load torque storage unit 18 (FIG. 2) is set as the target angular velocity. If ωref (rad / s) is set, the time is longer than the time required for one rotation of the mechanism unit obtained by the expression (8). This makes it possible to extract even the low-frequency load components of the mechanism.
(Equation 10)

With the load identification device configured as described above, it is possible to extract even the low-frequency load components of the mechanism unit.
Next, a description will be given of a load identification device when the cutoff frequency of the filter operation units 12 and 16 is equal to or lower than the mechanical resonance frequency of the transmission system including the motor 4 and the mechanism unit 5. The cutoff frequency of the low-pass filter in the filter operation unit 12 in FIG. 1 or the filter operation unit 16 in FIG. 2 is set to a frequency lower than the mechanical resonance frequency of the transmission system including the motor 4, the belt 6, and the mechanism unit 5. In this embodiment, in order to prevent the effect of mechanical resonance from appearing in the load torque model, assuming that the mechanical resonance frequency is ωm, the cutoff frequency ωLPF is 1/5 to 1/10 times as shown in Expression (9). I do.
(Equation 11)
ω _LPF = (0.25-0.1) x ω _m (9)
The load identification device configured as described above includes a filter operation unit that limits the cutoff frequency to a frequency lower than the mechanical resonance frequency of the transmission system including the motor and the mechanical system. As described below, the identification model can be input in a form converted into the motor axis, so that the mathematical mathematical model for the control system design support can be simplified.
[0016]
Next, a load identification method as an embodiment will be described. The driving device is the same as that in FIGS. As in the case of the load identification device of FIG. 1, data is acquired at a predetermined sampling frequency by a PC (personal computer) equipped with an A / D converter or an arithmetic device such as a DSP board or a CPU board. 6) is identified. The operation will be described with reference to the device configuration of FIG. 1 and the flowchart of FIG. 4. The motor current when the constant speed control is performed is detected by the current detection unit 9 and is converted into data for a predetermined time at a predetermined sampling frequency by an A / D converter. The current value is taken into the arithmetic unit, and stored in the RAM, HDD, or the like in the current value storage step S1. The data stored in the current value storage step S1 is sent to a motor load torque calculation step S2, where it is converted into a motor load torque by the calculation of equation (1).
Next, a predetermined filter process is performed on the motor load torque in a filter calculation step S3. This is low-pass filter processing for the purpose of cutting high-frequency noise and limiting the measurement band. When the filter calculation process is an IIR filter, it can be realized by calculating the state space equation (2) and the output equation (3). Next, the motor load torque value after the filter processing is sent to a Fourier analysis step S4, where a Fourier transform is performed. Next, the analysis result is sent to a frequency extraction step S5, and a frequency component having a gain equal to or more than a predetermined value is extracted. In the time function conversion step S6, the extracted frequency component is converted into a time function in the form of a cosine function from the gain and phase for each extracted frequency. The sum of the extracted cosine functions of all the frequencies is the identified load torque model. The identified load torque model (Equation 6) is expressed as Expression (6). In the load identification method configured as described above, the motor load torque model can be easily identified by a simple method.
[0017]
Next, a load identification method when the load identification device has the configuration shown in FIG. 2 will be described. The driving device is the same as that in FIGS. A PC (personal computer), an A / D converter, a DSP board, a CPU board, etc., having an analog operation unit for converting a detected current value into a motor load torque, similarly to the load identification device of FIG. The data is acquired at a predetermined sampling frequency by the arithmetic unit (1), and the load torque model is identified. The operation will be described with reference to the apparatus configuration of FIG. 2 and the flowchart of FIG. 5. The motor current when the constant speed control is performed is detected by the current detection unit 9. A predetermined filter process is performed on the detected current value in a filter operation step S7 of the analog operation unit. This is low-pass filter processing for the purpose of cutting high-frequency noise and limiting the measurement band.
Next, it is sent to a motor load torque calculation step S8 and is converted into a motor load torque by the calculation of the equation (1). Since the motor load torque is a voltage signal, it is taken into the arithmetic unit from the A / D converter at a predetermined sampling frequency, and stored in the RAM, HDD, or the like in the load torque storage step S9. In S10, it is determined whether data has been acquired for a predetermined time. If the data acquisition is not completed, the process returns to the load torque storage step S9 to acquire and store data from the A / D converter. If it is determined in S10 that the data acquisition has been completed, the process proceeds to Fourier analysis S4. The following operations are the same as those in S4 and subsequent steps in FIG. In the load identification method configured as described above, the motor load torque model can be easily identified by a simple method.
By the way, in the filter operation step S3 of FIG. 4 or the filter operation step S7 of FIG. 5, identification is performed for high-frequency noise cut unnecessary for load identification such as driver switching noise, motor brush noise, and circuit noise. A low-pass filter is set in order to limit the load band. The operation is performed by performing the above-described equations (2) and (3) in the filter operation step S3 of FIG. 4 or the filter operation step S7 of FIG. By limiting the band by the low-pass filter, the number of data acquired at the sampling frequency can be reduced, and the data capacity can be reduced. By providing the filter operation steps S3 and S7 in this manner, noise and unnecessary band data can be removed.
[0018]
Next, a load identification method in the case of including a position function conversion step in which the load of the identified time function is set as the load of the position function based on the position and speed will be described with reference to the flowchart of FIG. The steps before the time function conversion step S6 in FIG. 6 are the same as the steps before the time function conversion step S6 in FIG. 4 or FIG. The load torque model (Equation 6) of the time function identified by the load identification method of FIG. 4 or 5 is converted into a position function (Equation 8) using position and velocity in a position function conversion step S11. In the position function conversion step S11, a process of converting Expression (6) into Expression (7) is performed. According to the load identification method configured as described above, the identified load torque model can be converted into a format that can be easily developed into control system design support means or the like.
Next, a description will be given of a load identification method when the length of the predetermined time for storing the acquired data is one rotation or more of the mechanical unit. In the case of the driving device shown in FIG. 1 or FIG. 2, the time tlength for storing data in the current value storage step S1 in the load identification method in FIG. 4 or the load torque storage step S9 in the load identification method in FIG. When (rad / s) is set, the time required for one rotation of the mechanism unit obtained by the equation (8) is set longer. With the load identification method configured as described above, it is possible to extract even low-frequency load components of the mechanism unit.
[0019]
Next, the load when the cut-off frequency in the filter calculation step S3 of FIG. 4 or the filter calculation step S7 of FIG. 5 is set to a frequency lower than the mechanical resonance frequency of the transmission system including the motor 4, the belt 6, and the mechanism 5 The identification method will be described. Here, in order to prevent the influence of the mechanical resonance from appearing in the load torque model, the cutoff frequency ωLPF is set to 1/5 to 1/10 times assuming the mechanical resonance frequency ωm. The filter operation of the equation (9) is performed in the filter operation step S3 of FIG. 4 or the filter operation step S7 of FIG. In the load identification method configured in this manner, the cutoff frequency is limited to a frequency lower than the mechanical resonance frequency of the transmission system including the motor and the mechanical system. As described below, the identification model can be input in a form converted into the motor axis, so that the mathematical mathematical model for the control system design support can be simplified.
In the load identification device and the load identification method described above, the configuration and operation are described as being limited to the load identification device and the load identification method alone. However, these load identification device and the load identification method are actual devices, for example, It is incorporated in the drive mechanism of the stage control device, robot, copier, printer, etc., and performs load identification at a predetermined timing, such as immediately after startup, and if the identified load is larger than the load assumed at the time of design, the device is abnormal. It can be used for the device abnormality determination and the control parameter changing means based on the identified load.
[0020]
Next, a control system design support method as an embodiment will be described. This control system design support method is for a case in which the disturbance changes according to any one of the rotation angle or position of the motor and the rotation angle or position of the mechanism in the mathematical model. The driving device including the mechanism to be measured described with reference to FIG. 1 or FIG. 2 is constructed on an arithmetic device as a speed control system mathematical model of a control system design support method as shown in FIG. The mathematical model 23 composed of a motor and a mechanism receives a current value and outputs a rotation angle of the mechanism. The output rotation angle is input to the speed calculation unit model 24 to output an angular speed signal. The angular velocity signal is compared with the target angular velocity model 20 to calculate a velocity deviation. This speed deviation is input to a compensator model 21 which is a speed controller model.
The compensator model 21 performs a phase compensation or the like on the speed deviation and outputs a current command value which is an operation amount. The output current command value is input to the motor driver model 22. The motor driver model 22 supplies a current to a mathematical model 23 composed of a motor and a mechanism according to the current command value. Using such a speed control system mathematical model, a response simulation of speed control is performed. The speed control system mathematical model reflects the load torque model (Equation 6) of the position function, which is identified by the load identification device and the load identification method described above, and represented by Expression (7). The position of the mechanism is input to the load torque model (Equation 6) 25 of the position function. Here, the output of the mechanism unit is a rotation angle, but is converted into a position according to the expression (7) and input. The load torque model (Equation 6) 25 of the position function outputs a load torque according to the position. The output load torque is converted into a current value Id (x) corresponding to the load torque by the current converter 26, and is applied to the speed control system mathematical model by the comparator 27 in the form of a current value.
The current conversion unit 26 performs conversion according to equation (10).
(Equation 12)

Here, for simplicity, the motor and the mechanism are considered as an integrated model, and the load torque is converted and applied to a current value equivalent to the load torque. However, if the motor and the mechanism are divided, the motor output A model that applies load torque to torque may be used. In the control system design support method configured as described above, the load model identified by focusing on load characteristic extraction in a relatively low region can be used as a load disturbance applied to the motor, and the load can be varied based on the position information of the mathematical model.
[0021]
Next, a load data table corresponding to any one of the rotation angle or position of the motor of the mathematical model and the rotation angle or position of the mechanism is created in advance, and this is used as a disturbance model applied to the motor of the mathematical model, and the mathematical model The control system design support method in the case where the disturbance is changed by selecting the value of the load data table according to any one of the rotation angle or position of the motor and the rotation angle or position of the mechanism unit will be described. In this control system design support method, the identified load torque model (Equation 6) of the equation (7) is calculated in advance, and is prepared as a load torque data table in which the position data and the load torque data are associated. The load torque data table is used as the load torque model (Equation 6) 25 of claim 11, and a load torque corresponding to the input position is output. In the control system design support method configured as described above, since the load model is converted into a data table, the calculation of Expression (7) in the load torque model (Equation 6) 25 becomes unnecessary, so that the calculation load of the simulation is reduced. be able to.
[0022]
Next, the load of the time function for each frequency component obtained by the load identification device of FIGS. 1 and 2 or the load identification method of FIGS. 4 and 5 is used as a disturbance model applied to the motor of the mathematical model. A control system design support method in the case where the disturbance changes accordingly will be described with reference to FIG. The drive device including the mechanism to be measured described with reference to FIG. 1 or FIG. 2 is constructed on an arithmetic device as a speed control system mathematical model of a control system design support method as shown in FIG. The mathematical model 23 composed of a motor and a mechanism receives a current value and outputs a rotation angle of the mechanism. The output rotation angle is input to the speed calculation unit model 24 to output an angular speed signal. The angular velocity signal is compared with the target angular velocity model 20 to calculate a velocity deviation. The speed deviation is input to a compensator model 21 which is a speed controller model.
The compensator model 21 performs a phase compensation or the like on the speed deviation and outputs a current command value which is an operation amount. The output current command value is input to the motor driver model 22. The motor driver model 22 supplies a current to a mathematical model 23 including a motor and a mechanism according to a current command value. The response simulation of speed control is performed using such a speed control system mathematical model. The speed control system mathematical model reflects the load torque model (Equation 6) of the time function identified by the load identification device and the load identification method described above and represented by the equation (6). The simulation time 28 is input to the load torque model (Equation 6) 29 of the time function. The load torque model (Equation 6) 29 of the time function outputs a load torque according to the simulation time. The output load torque is converted into a current value Id (x) corresponding to the load torque by the current conversion unit 26, and is applied to the speed control system mathematical model by the comparator 27 in the form of a current value. The current converter 26 performs the conversion according to the equation (10).
With the control system design support method configured as described above, the load model identified by focusing on load characteristic extraction in a relatively low region can be used as a load disturbance applied to the motor, and the load can be varied based on the time information of the mathematical model. Here, for simplicity, the motor and the mechanism are considered as an integrated model, the load torque is converted into a current value equivalent to the load torque and applied, but in the case of a model in which the motor and the mechanism are divided, A model that applies a load torque to the motor output torque may be used.
[0023]
Next, a load data table corresponding to time is created in advance using the load of the time function for each frequency component obtained by the load identification device of FIG. 3 or the load identification method of FIG. A description will be given of a control system design support method in a case where a disturbance is added and a disturbance is changed by selecting a value of a load data table according to a time change of a mathematical model. In this control system design support method, the identified load torque model (Equation 6) of Expression (6) is calculated in advance, and a time torque data and a load torque data table corresponding to the load torque data are prepared. The load torque data table is used as the load torque model (Equation 6) 29 in FIG. 12 and a load torque corresponding to the input simulation time 28 is output. In the control system design support method configured as described above, since the load model is converted into a data table, the calculation of Expression (6) in the load torque model (Equation 6) 29 becomes unnecessary, so that the calculation load of the simulation can be reduced. Can be.
In the load identification device, the load identification method, and the control system design support method according to the embodiment described above, the description has been given based on a driving device using a rotary motor. The present invention can be applied by assuming that the load torque is not the load torque applied to the shaft but the load force applied to the mover of the linear motor, and the rotation angle and the number of rotations correspond to the position and speed.
[0024]
【The invention's effect】
As described above, according to the first aspect, a frequency analysis unit that performs frequency analysis on a motor load value, a frequency extraction unit that extracts a frequency from a result analyzed by the frequency analysis unit, A time function conversion unit for converting to a time function is provided, and the sum of the calculated time functions is identified as a load applied to the motor, so that the motor load model can be easily configured with a simple configuration regardless of the configuration of the mechanism. Can be provided.
According to the second aspect of the present invention, since the filter operation unit for limiting the band of the load to be identified is provided, it is possible to provide a load identification device capable of removing noise and data of an unnecessary band.
According to the third aspect of the present invention, since the position function conversion unit is provided which uses the identified load of the time function as the load of the position function according to the position and speed, the identified load model is expanded to control system design support means and the like. It is possible to provide a load identification device that can be converted into a format that can be easily performed.
According to the fourth aspect, the length of the predetermined time for storing the acquired data in the data storage unit is set to one or more rotations or one or more scans of the mechanism unit. A load identification device capable of extracting even load components can be provided.
According to the fifth aspect, by providing the filter operation unit that limits the cutoff frequency to a frequency lower than the mechanical resonance frequency of the transmission system including the motor and the mechanical system, the identified load model becomes equal to or lower than the mechanical resonance frequency. Therefore, it is possible to input the identification model in a form converted into the motor axis, and it is possible to provide a load identification device capable of simplifying the mathematical model of the mechanical system for supporting the control system design.
According to claim 6, a frequency analysis step of performing a frequency analysis on a motor load value, a frequency extraction step of extracting a frequency from a result analyzed by the frequency analysis unit, and a time of converting the extracted frequency into a time function A function conversion step is provided, and the sum of the calculated time functions is identified as a load applied to the motor. Therefore, regardless of the structure of the mechanism, the motor load torque model (Equation 6) can be easily obtained by a simple method. A load identification method that can be identified can be provided.
[0025]
According to the seventh aspect, since a filter operation step for limiting the band of the load to be identified is provided, it is possible to provide a load identification method capable of removing noise and data of an unnecessary band.
According to the eighth aspect, since there is provided a position function converting step in which the load of the identified time function is set as the load of the position function by the position and the speed, the identified load model is expanded to control system design support means and the like. It is possible to provide a load identification method that can be converted into a format that can be easily performed.
According to the ninth aspect, the length of the predetermined time for storing the acquired data in the data storing step is set to a time of one rotation or more of the mechanism unit or one scan or more. A load identification device capable of extracting even load components can be provided.
According to the tenth aspect, the identified load model becomes equal to or lower than the mechanical resonance frequency by performing the filter operation step of limiting the cutoff frequency to a frequency lower than the mechanical resonance frequency of the transmission system including the motor and the mechanical system. Therefore, it is possible to input the identification model in a form converted into the motor axis, and it is possible to provide a load identification method capable of simplifying a mechanical model mathematical model for control system design support.
According to the eleventh aspect, there is provided a design support method capable of changing a load based on position information of a mathematical model by using a load model identified by focusing on load characteristic extraction in a relatively low region as a load disturbance applied to a motor. be able to.
According to the twelfth aspect, it is possible to provide a design support method capable of reducing a calculation load by converting a load model into a data table and selecting a value in the data table according to a rotation angle or a position of the mechanism unit.
According to the thirteenth aspect, there is provided a design support method capable of changing a load according to time information of a mathematical model by using a load model identified by focusing on load characteristic extraction in a relatively low region as a load disturbance applied to a motor. be able to.
According to the fourteenth aspect, it is possible to provide a design support method capable of reducing a calculation load by using a load of a time function and converting a load model into a data table.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a load identification device.
FIG. 2 is a diagram illustrating a load identification device when a configuration that is partially different from the load identification device of FIG. 1 is employed;
FIG. 3 is a diagram showing a load identification device when configured to convert a load model of a time function into a position function.
FIG. 4 is a diagram showing a load identification method (the case described using the load identification device of FIG. 1).
FIG. 5 is a diagram showing a load identification method (the case described using the load identification device of FIG. 2).
FIG. 6 is a diagram illustrating a load identification method when a position function conversion step is provided.
FIG. 7 is a diagram illustrating a control system design support method in a case where disturbance is changed according to any one of a rotation angle or a position of a motor and a rotation angle or a position of a mechanism in a mathematical model.
FIG. 8 is a diagram showing a detected motor load torque.
FIG. 9 is a diagram showing an analysis result.
FIG. 10 is a diagram showing an extraction result.
FIG. 11 is a diagram showing a conversion result.
FIG. 12 is a diagram for explaining a control system design support method in a case where a load of a time function for each frequency component is used as a disturbance model applied to a motor of a mathematical model, and the disturbance changes according to a time change of the mathematical model. It is.
[Explanation of symbols]
1 target angular velocity, 2 compensator, 3 motor driver, 4 motor, 5 mechanism section, 6 belt, 7 encoder, 8 speed calculation section, 9 current detection section, 10 current value storage section, 11, 17 motor load torque calculation section, 12, 16 filter operation unit, 13 Fourier analysis unit, 14 frequency extraction unit, 15 time function conversion unit, 18 load torque storage unit, 19 position function conversion unit, 20 target angular velocity model, 21 compensator model, 22 motor driver model, 23 Mathematical model, 24 Speed calculation unit model, 25 Load torque model, 26 Current conversion unit, 27 Comparator, 28 hours, 29 Load torque model

Claims (14)

A motor, a mechanism driven by the motor, at least one of a rotation angle or position of the motor, position detection means for detecting a rotation angle or position of the mechanism, and a speed for calculating a speed signal A load identification device that identifies a load model applied to the motor in a drive device including a calculation unit and a control unit that drives the motor or the mechanism unit at a predetermined speed or an angular speed using the speed signal. ,
A current detection unit that detects a current of the motor;
A motor load calculator that calculates a motor load value from the current value and the motor constant detected by the current detector;
A frequency analysis unit that performs frequency analysis on the motor load value,
A frequency extraction unit that extracts a frequency from the result of the analysis by the frequency analysis unit,
A time function conversion unit that converts the frequency into a time function for each extracted frequency,
A load identification device for identifying a sum of the calculated time functions as a load applied to the motor. The load identification device according to claim 1, further comprising a filter operation unit that limits a band of a load to be identified. 3. The load identification device according to claim 1, further comprising a position function conversion unit that uses the identified load of the time function as the load of the position function according to the position and the speed. 3. The load identification device according to claim 1, further comprising a data storage unit that sets the length of the predetermined time for storing the acquired data to be equal to or longer than one rotation of the mechanism unit or equal to or longer than one scan. A load identification device characterized by the above-mentioned. 3. The load identification device according to claim 2, wherein a cutoff frequency of the filter operation unit is set to be equal to or lower than a mechanical resonance frequency of a transmission system including the motor and the mechanism unit. 4. A motor, a mechanism driven by the motor, at least one of a rotation angle or position of the motor, position detection means for detecting a rotation angle or position of the mechanism, and a speed for calculating a speed signal A load identification method for identifying a load model applied to the motor in a drive device including a calculation unit and a control unit that drives the motor or the mechanism unit at a predetermined speed or an angular speed using the speed signal. ,
A motor load calculation step of calculating a motor load value from a current value and a motor constant detected by a current detection unit that detects the current of the motor,
A frequency analysis step of performing a frequency analysis on the motor load value,
A frequency extraction step of extracting a frequency component from the result analyzed by the frequency analysis unit,
By a time function conversion step of converting each extracted frequency component into a time function,
A load identification method comprising: identifying a sum of the calculated time functions as a load applied to the motor. 7. The load identification method according to claim 6, further comprising a filter operation step of limiting a band of a load to be identified. The load identification method according to claim 6 or 7, further comprising a position function conversion step of using the identified load of the time function as the load of the position function based on the position and the speed. 8. The load identification method according to claim 6, further comprising a data storage step of setting a length of a predetermined time for storing the acquired data to be one or more rotations of the mechanism unit or one or more scans. A load identification method characterized by the following. 8. The load identification method according to claim 7, wherein a cutoff frequency in the filter operation step is set to be equal to or lower than a mechanical resonance frequency of a transmission system including the motor and the mechanism. A motor, a mechanism driven by the motor, at least one of a rotation angle or position of the motor, position detection means for detecting a rotation angle or position of the mechanism, and a speed for calculating a speed signal A control device that has a calculation device and a control unit that drives the motor or the mechanism unit at a predetermined speed or an angular speed using the speed signal as a mathematical model, and performs a response analysis of the drive device by numerical calculation. In the system design support method,
The load of the position function for each frequency component obtained by the load identification device according to claim 3 or the load identification method according to claim 8 is a disturbance model applied to the motor of the mathematical model, and the rotation angle of the motor of the mathematical model Alternatively, a disturbance is changed according to any one of a position, a rotation angle and a position of the mechanism, and a control system design support method. A motor, a mechanism driven by the motor, at least one of a rotation angle or position of the motor, position detection means for detecting a rotation angle or position of the mechanism, and a speed for calculating a speed signal A control device that has a calculation device and a control unit that drives the motor or the mechanism unit at a predetermined speed or an angular speed using the speed signal as a mathematical model, and performs a response analysis of the drive device by numerical calculation. In the system design support method,
Using the load of the position function for each frequency component obtained by the load identification device according to claim 3 or the load identification method according to claim 8, the rotation angle or the position of the motor of the mathematical model, and the rotation of the mechanism unit in advance. Create a load data table corresponding to any one of the angle or the position, as a disturbance model applied to the motor of the mathematical model, the rotation angle or position of the motor of the mathematical model, the rotation angle of the mechanism unit Alternatively, a disturbance is changed by selecting a value of the load data table according to any one of the positions. A motor, a mechanism driven by the motor, at least one of a rotation angle or position of the motor, position detection means for detecting a rotation angle or position of the mechanism, and a speed for calculating a speed signal A control device that has a calculation device and a control unit that drives the motor or the mechanism unit at a predetermined speed or an angular speed using the speed signal as a mathematical model, and performs a response analysis of the drive device by numerical calculation. In the system design support method,
The load of the time function for each frequency component obtained by the load identification device according to claim 1 or the load identification method according to claim 6 is set as a disturbance model applied to the motor of the mathematical model, and the load is determined according to a time change of the mathematical model. A control system design support method, wherein the disturbance is changed. A motor, a mechanism driven by the motor, at least one of a rotation angle or position of the motor, position detection means for detecting a rotation angle or position of the mechanism, and a speed for calculating a speed signal A control device that has a calculation device and a control unit that drives the motor or the mechanism unit at a predetermined speed or an angular speed using the speed signal as a mathematical model, and performs a response analysis of the drive device by numerical calculation. In the system design support method,
Using the load of the time function for each frequency component obtained by the load identification device according to claim 3 or the load identification method according to claim 8, a load data table corresponding to time is created in advance, and the load data table is defined by the mathematical model. A control system design supporting method, wherein a disturbance model applied to the motor is used, and the disturbance changes by selecting a value of the load data table according to a time change of the mathematical model.

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