JP2004328829A - Method and device for controlling motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adjust a control parameter with high precision in a short time both during normal operation and under various conditions on a load side. <P>SOLUTION: The controller of a motor drives a motor 13 based on the instruction of a motor control part 11 and comprises a drive mechanism part 12 connected to the motor. It comprises a simulation part 20 composed of a motor model 23 that simulates the motor 13, a mechanism model part 22 that simulates the mechanism part 12, and a control model part 21 that simulates the motor control part 11, a state quantity comparison part 31 which compares the identical state quantity between an actual machine part 10 composed of the motor control part 11, the motor 13, and the mechanism part 12 and the simulation part 20, an evaluation quantity calculating part 32 which generates an evaluation quantity using a state quantity, and a control parameter adjusting part 33 that adjusts the control parameter of the motor control part 11 so that the evaluation quantity is adjusted within a specified value. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００２８】
ここで、ｍ_ｉはリンクｉの質量、Ｌ_ｉは軸から重心までの距離、ａ_ｉはリンク長さである。また、速度に関する干渉力の項は速度に依存しており、慣性項に比較して変化は緩やかであり、速度制御ループで補償されるため、無視して考えられる。その場合、式（１）と（２）は次のように表せる。
【００２９】
【数２】

【００３０】
よって、式（３）と（４）は以下のように表現することができる。
【００３１】
【数３】

【００３２】
ここで、
【００３３】
【数４】

【００３４】
また、Ｉ_ｉは重心周りの慣性モーメント、Ｎ_ｉはｉ軸モータの減速機の減速比、Ｉ_ｉｍはモータのモータロータのイナーシャ（等価慣性モーメント）である。
ｍ_ｉ、Ｌ_ｉ、ａ_ｉ、Ｎ_ｉは既知であり、主慣性であるＪ_１１とＪ_２２は、負荷イナーシャＪＬとして既に求められているため、特定の姿勢θ_１とθ_２での重心周りの慣性モーメントＩ_ｉを式（６）〜（８）から求め、相互慣性であるＪ_１２とＪ_２１を求めることができる。
【００３５】
式（５）は、加減速時に２軸目が１軸目に作用する干渉トルクτ_１２と１軸目が２軸目に作用する干渉トルクτ_２１が、以下のように表せることを意味する。
【００３６】
【数５】

【００３７】
よって、図８に示すように、求められた相互慣性のパラメータＪ_１２（＝Ｊ_２１）を元に、実機部１０に相互干渉部３５を配置する。
【００３８】
（２）相互慣性モデルのパラメータＪ_１２の調整
上位コントローラから、通常運転時の位置（角度）指令を、前記実機部１０の前記モータ制御部１１ａ、１１ｂ及び前記シミュレーション部２０の前記制御モデル部２１ａ、２１ｂに入力する。この指令は、図７（ｂ）に示すように１軸目を・・θ_１で、２軸目を・・θ_２で動作させることで、２軸目に干渉力τ_２１を与え、実機部とシミュレーション部の挙動（軌跡ズレ）を比較する。
実機部の相互干渉補償部３５の相互慣性Ｊ_ｒ１２（＝Ｊ_ｒ２１）と、実際に実機部の機構部に作用している相互慣性Ｊ_ｓ１２（＝Ｊ_ｓ２１）が一致していない場合には、実機部とシミュレーション部に軌跡ズレが発生する。ここでは、実機部とシミュレーション部の軌跡ズレを定量的に判断することで、相互干渉補償部３５の相互慣性パラメータを調整する。
【００３９】
実機部とシミュレーション部の軌跡の比較をするために、順変換部３４では、前記モータ制御部１１の位置検出器１４ａ、１４ｂの位置ＦＢと、前記制御モデル部２１の位置検出器モデル２４ａ、２４ｂの位置ＦＢをそれぞれ順変換し、直交座標系における実機部とシミュレーション部のロボット先端の位置ＦＢ（状態量）を求める。前記状態比較部３１では、２つの前記位置ＦＢを差分して状態量比較値を求め、評価量演算部３２で予め決められたしきい値以内であるかどうかを判断する。
しきい値以内であれば、制御パラメータ（相互慣性）の調整を終了する。これで実際に作用している相互干渉と実機部の相互干渉補償部３５が近似値になったことになる。しきい値以上であれば、以下に示すように制御パラメータ調整部３３で相互干渉補償部３５の制御パラメータＪ_１２を変更し、しきい値以内になるまで繰り返す。
【００４０】
相互慣性のパラメータＪ_１２の変更方法は、図７（ｂ）に示すように実機部の軌跡とシミュレーション部の軌跡のズレ量（ΔＸ，ΔＹ）から、相互慣性のパラメータＪ_１２を変更する大きさと正負方向について判断する。これには、直交座標系における軌跡のズレ量を、ヤコビアンと呼ばれる関節座標系と作業座標系の微小変位関係式の逆行列を用いて、関節座標系のズレ量に変換する。２軸のヤコビアンＪａｃｏｂｉａｎは以下の式で表すことができる。
【００４１】
【数６】

【００４２】
ここで、θ_１２＝θ_１＋θ_２
また、その逆行列Ｊａｃｏｂｅａｎ^−１は以下の式で表すことができる。
【００４３】
【数７】

【００４４】
よって、直交座標系における軌跡のズレ量（ΔＸ，ΔＹ）と関節座標系における角度誤差（Δθ_１，Δθ_２）は以下のように表すことができる。
【００４５】
【数８】

【００４６】
また、関節座標系の剛性から、角度誤差とトルクの関係は以下の式で表すことができる。
【００４７】
【数９】

【００４８】
ここで、Ｋ＝Ｋｐ・Ｋｖ・Ｊ
よって、相互慣性のパラメータＪ_１２は、式（１３）と以下の式を解くことで得ることができる。
【００４９】
【数１０】

【００５０】
実際の作業で使用する位置指令を用いて以上の作業を繰り返すことで、多軸ロボットの相互干渉による干渉力補償の制御パラメータを調整することができる。
【００５１】
【発明の効果】
以上述べたように、請求項１のモータの制御装置によれば、実機部及びシミュレーション部を並列に配置し、入力された同一の指令に応じて機構部及び機構部モデルの状態量を比較し、予め決められたしきい値以内に状態量入るまで、同一指令による動作の比較から実機部の制御パラメータ値の変更を繰り返すことにより、重力や動摩擦等の影響を受けずに、動作領域の制限などの制約を受けずに、制御部の制御パラメータを自動的に調整することができる。
請求項２記載のモータの制御装置によれば、複数のモータ制御の状態量で調整動作を実施することにより、複数軸の場合の軸間に生じる制御パラメータも調整することができる。
請求項３記載のモータの制御装置によれば、前記モータ制御部のゲイン調整は前記モータ制御部の速度、加速度の振動特性が前記シミュレーション部の同信号に比較して一定レベル以下になるように調整することにより、状況を的確に判断して運転条件に依らず、正確にモデルパラメータを同定できる。
請求項４記載のモータの制御装置によれば、前記振動特性の評価はＦＦＴなどの振動周波数成分の大きさを評価する手法を用いることにより、問題となる振動成分を的確に判断して、正確に制御パラメータの調整を行うことができる。
請求項５記載のモータの制御装置によれば、振動特性の評価を実施後、前記モータ制御部の制御構造を変化させることにより、実機及びモデルの機構構成に合った制御系を構築でき、制御対象をより的確に制御できる。
請求項６記載のモータの制御装置によれば、状態量の瞬時値又は蓄積値を用いたゲイン調整結果に応じて調整動作を終了することにより、モデルパラメータの不用意な変更や、ノイズによる影響を防止できる。
請求項７記載のモータの制御装置によれば、作業者又は前記評価量演算部の判断により、前記調整動作の実行を選択することにより、作業者が作業内容に応じて制御パラメータの更新ができ、制御パラメータの不用意な変更を防止できる。また、自動的にパラメータの更新ができる。
請求項８記載のモータの制御装置によれば、前記モータ制御部の制御パラメータを位置ループゲイン又は速度ループゲインとすることにより、高精度の位置決めや速度応答が可能となる。
請求項９記載のモータの制御装置によれば、実機部及びシミュレーション部を並列に配置し、前記実機部に作用する外力を補償する外力補償部と、前記実機部と前記シミュレーション部の同一状態量から前記外力補償部のパラメータを調整する補償パラメータ調整部とを備えたことにより、重力と摩擦の外力補償パラメータを調整でき、制御パラメータ調整の精度も向上できる。
請求項１０記載のモータの制御方法によれば、実機部及びシミュレーション部を並列に配置し、入力された同一の指令に応じて機構部及び機構部モデルの状態量を比較し、予め決められたしきい値以内に状態量入るまで、同一指令による動作から実機部の制御パラメータ値の変更を繰り返すことにより、重力や動摩擦等の影響を受けずに、機構部の周りに複数の周辺機器がある場合でも動作領域の制限などの制約を受けずに、制御部の制御パラメータを簡単に調整することができる。
請求項１１記載のモータの制御方法によれば、複数の前記モータの相互干渉を補償し、相互干渉のパラメータを調整することにより、相互干渉の制約を受けずに、制御部の制御パラメータを自動的に調整することができる。
【図面の簡単な説明】
【図１】本発明の第１の基本構成図
【図２】本発明の第１の具体的実施例を表すブロック図
【図３】本発明の第１の具体的実施例における応答波形１
【図４】本発明の第１の具体的実施例における応答波形２
【図５】本発明の第２の具体的実施例における応答波形
【図６】本発明の第３の具体的実施例を表すブロック図
【図７】本発明の第４の具体的実施例を表すモデル
【図８】本発明の第４の具体的実施例を表すブロック図
【図９】従来の制御方式を示す図
【符号の説明】
１０：実機部
１１：モータ制御部
１２：機構部
１３：モータ
１４：位置検出器
１５：外力補償部
２０：シミュレーション部
２１：制御モデル部
２２：機構モデル部
２３：モータモデル
２４：位置検出器モデル
２５：外力補償部モデル
３１：状態量比較部
３２：評価量演算部
３３：制御パラメータ調整部
３４：パラメータ同定部
３５：相互干渉補償部
１１１：位置速度ループ
１１２：アンプ
１２１：２次側機構部
１２２：減速機
２１１：位置速度制御ループモデル
２１２：アンプモデル
２２１：２次側機構部モデル
２２２：減速機モデル
３１１：振動成分抽出部[0001]
[Industrial applications]
The present invention relates to a motor control device, and more particularly, to a motor control device and a control method for adjusting a motor control parameter.
[0002]
[Prior art]
FIG. 9 shows a block diagram of a motor control system applied to the motor control device. Since the characteristics of the motor control system directly affect the entire operation including the mechanism system and the motor, when high trajectory accuracy and speed responsiveness are required, adjustment of the control parameters of the control device is extremely important.
A method for adjusting the control parameters, particularly, the control parameters such as the position gain and the speed gain, will be described. In a motor control system, it is necessary to determine a loop gain that is as large as possible while taking care not to cause oscillation from the inner loop, in order to maintain good steady-state characteristics and quick response and rigidity. Conventionally, an operator has set an appropriate gain based on his or her experience so that vibration and abnormal noise do not occur from the motor. This is done by inputting a specific gain in advance and causing the motor to perform an operation similar to actual use, so that when vibration or abnormal noise occurs, the gain is reduced, and when position or speed response delay occurs. Is a method of adjusting the gain so as to obtain a desired motor performance by taking steps such as greatly changing the gain.
[0003]
Further, as a conventional example 1 of a conventional apparatus for automatically adjusting a control gain of a motor, a test pattern generator for generating a pattern (including a ramp-shaped speed command) for changing a rotation speed of a motor and an integration of a speed control arithmetic unit are provided. A switch for interrupting the output to the tester, a speed loop gain multiplier capable of switching to a test gain, and a gain adjuster. In this control device, the load inertia is controlled by a gain adjuster that changes a loop gain of a motor control loop according to a difference between an output of a test pattern of a ramp-shaped speed command to be actually driven and a speed detection unit that detects a rotation speed of the motor. , And auto-tuning to set a loop gain more suitable for the load inertia becomes possible (see Patent Document 1).
Further, as a second conventional example, in a control system in which a value obtained by multiplying a speed deviation by a gain of a control loop is added to a control target to perform proportional control of the control target, an oscillation region moves from an oscillation region toward a stable region with respect to an increase in the speed deviation. A gain adjustment system having a characteristic of decreasing the gain is formed, and a gain converging to the oscillation limit is obtained (see Patent Document 2).
[0004]
[Patent Document 1]
JP-A-6-70566
[Patent Document 2]
JP-A-9-106303
[0005]
[Problems to be solved by the invention]
However, in the conventional method of adjusting the gain of the control parameter, it is necessary to rely on the experience of a skilled person, and depending on the operator who tunes, not only a great amount of time is required to obtain the optimum gain, but also There is a problem that the motor control system may oscillate. Further, in order to confirm the occurrence of vibration, the operator needs to separately measure the position and speed information of the motor using a measuring instrument.
Further, in the first conventional example, there is a problem that a special adjustment operation is required when adjusting a parameter, and the parameter cannot be adjusted during a normal operation. When the load of the mechanical unit is frequently changed, it is necessary to stop the normal operation each time, secure an operation range in which the parameter can be adjusted, and execute a special adjustment operation. Further, even if the adjustment is performed with a dedicated operation command, if the operation is performed with an operation command used in actual work, there is a risk that the control system oscillates due to a difference in conditions. Further, in terms of accuracy, when friction acts on a drive system including a motor, there is a problem that parameter adjustment cannot be accurately performed because a position deviation and a detected speed value are affected.
[0006]
Similarly, in the above-described conventional art 2, there is a problem that, in terms of accuracy, when gravity or friction acts on the motor, the speed deviation is affected, so that parameter adjustment cannot be performed accurately. There is also a problem that only the adjustment of the speed loop gain of the control parameter is supported.
Therefore, an object of the present invention is to adjust a control parameter with high accuracy in a short time, even during normal operation and under various conditions on the load side, without requiring a special operation for adjustment.
[0007]
[Means for Solving the Problems]
The present invention has the following configuration in order to solve the above problems.
A motor control device according to claim 1, wherein the motor control device drives a motor based on a command from a motor control unit and has a drive mechanism connected to the motor. A simulation unit having a mechanism model unit simulating the mechanism unit, a control model unit simulating the motor control unit, and the same as the real machine unit including the motor control unit, the motor and the mechanism unit, and the simulation unit A state quantity comparison unit that compares state quantities, an evaluation quantity calculation unit that creates an evaluation quantity using the state quantities, and adjusts a control parameter of the motor control unit so as to adjust the evaluation quantity to a fixed value. And a control parameter adjusting unit.
[0008]
A motor control device according to a second aspect is characterized in that an adjustment operation is performed using the state quantities of a plurality of motors.
According to a third aspect of the present invention, in the motor control device, the control parameter adjustment unit adjusts based on a vibration characteristic of a speed and an acceleration of the motor control unit.
According to a fourth aspect of the present invention, in the motor control device, the vibration characteristic uses a vibration frequency component.
According to a fifth aspect of the present invention, in the motor control device, the control parameter adjusting unit changes a control structure of the motor control unit.
According to a sixth aspect of the present invention, in the motor control device, the state quantity uses an instantaneous value or an accumulated value.
According to a seventh aspect of the present invention, in the motor control device, the model parameter adjustment unit selects whether or not to perform the adjustment operation based on a result of an external unit or the evaluation amount calculation unit.
[0009]
The motor control device according to claim 8, wherein the control parameter of the motor control unit is a position loop gain or a speed loop gain.
10. The motor control device according to claim 9, wherein the motor is driven based on a command from a motor control unit, and the motor control device includes a mechanism connected to the motor. A simulation unit having a mechanism model unit simulating a unit and a control model unit simulating the motor control unit; an external force compensation unit for compensating an external force acting on the real machine unit; and the same state of the real machine unit and the simulation unit. A compensation parameter adjustment unit for adjusting a parameter of the external force compensation unit from an amount.
Further, the motor control method according to claim 10 drives the motor based on a command from the motor control unit, and the motor control method includes a mechanism connected to the motor, wherein the motor control unit and the motor A simulation unit that simulates a real machine unit composed of the mechanical unit, providing the same input to the real machine unit and the simulation unit, comparing the same state quantities of the real machine unit and the simulation unit, It is characterized in that control parameters are adjusted.
A method of controlling a motor according to claim 11 is characterized in that the mutual interference of the plurality of motors is compensated and a parameter of the mutual interference is adjusted.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
The basic configuration of the present invention will be described with reference to FIG. Here, for the sake of simplicity, it is assumed that there is one motor driven by the present control device, and the mechanism connected to the motor is a simple cylindrical load via a speed reducer.
In FIG. 1, the actual machine unit 10 includes a mechanism unit 12, a motor 13 connected to the mechanism unit 12, and a motor control unit 11 for controlling the motor 13. The simulation unit 20 includes a motor model 23 simulating the dynamic system of the motor 13, a mechanism model unit 22 simulating the dynamic system of the mechanism unit 12, and a control model unit 21 simulating the motor control unit 11. It is configured.
In the device that controls the motor of the control device, the real machine unit 10 and the simulation unit 20 are arranged in parallel, and each receives the same command from the upper controller. The real machine section 10 and the simulation section 20 output a torque command for controlling the mechanism section 12 and the mechanism section model 22 to the motor 13 and the motor model 23, respectively, in accordance with the input command. Here, the same command input from the host controller is an operation command used in actual work, and a pattern stored in advance may be reproduced and used, or a method of automatically creating a pattern from CAD data or the like. But it's fine. The use of a pre-stored pattern avoids interference with peripheral devices at the time of pattern creation, and thus has the advantage that there is no collision with peripheral devices during the identification operation.
[0011]
In the state quantity comparing section 31, the same state quantity (for example, position deviation or speed feedback) of the motor control section 11 and the control model section 22 in the real machine section 10 and the simulation section 20 or the mechanism section 12 And the same state quantity (for example, position feedback or the like) of the mechanism model unit 22 to generate a state quantity comparison value. The evaluation amount calculation unit 32 determines whether the control parameter of the motor control unit 11 of the actual machine unit 10 is optimally set based on whether the state amount comparison value created by the state amount comparison unit 31 is within a threshold value. Judge whether or not. Here, when the parameters of the actual device and the model completely match, that is, when the actual device and the simulation show exactly the same behavior, the determination criterion is that the state quantity comparison value ideally becomes 0.
[0012]
Here, when comparing with the threshold value, it is possible to select whether to use the instantaneous value of the state quantity comparison value or to use the accumulated value of the state quantity comparison value. Further, in the case of a mechanical device such as a robot to which a plurality of motors are connected, a value obtained by converting the state quantity comparison value into a rectangular coordinate value or the like can be used as the state quantity of the hand effector portion of the robot.
If the state quantity comparison value is equal to or greater than the threshold value, the control parameter adjusting unit 33 changes the values of the control parameters of the motor control unit 11 and the control model unit 21 in conjunction with each other, and the state quantity comparison value becomes a threshold. Until the value falls within the value, the control parameter value is changed from the operation by the same command. If the state quantity comparison value is within the threshold value, it is determined that the control parameters of the actual machine and the simulation have become approximate values, and the adjustment operation is terminated. Here, the method of changing the control parameter value uses a method of determining the correction direction based on the sign of the state quantity comparison value, and determining the correction amount based on the magnitude of the state quantity comparison value with respect to the threshold.
[0013]
Whether to perform the adjustment operation during the normal operation or to interrupt the normal operation and execute the special adjustment operation can be selected by the operator via the control device. Further, during the normal operation, the state quantity comparison value is successively monitored in the evaluation quantity calculation unit 32, and if the state quantity comparison value becomes large, it is determined whether or not adjustment is necessary or unnecessary. The operation may be executed.
[0014]
Hereinafter, a first specific example of the present invention will be described with reference to FIG.
The motor control unit 11 includes a position / speed control loop 111 and an amplifier 112. The motor control unit 11 inputs a position (angle) command for normal work and outputs a torque command to the amplifier 112, thereby The mechanism 13 is driven. The position / velocity control loop 111 uses, for example, the position proportional / velocity proportional integral control shown in FIG. Similarly, the control model unit 21 also includes a position / speed control loop model 211 and an amplifier model 212. By inputting a position (angle) command during normal operation and outputting a torque command to the amplifier model 212. , And a model structure for driving the mechanism model unit 22.
[0015]
Further, when gravity acts on the mechanical unit assumed in the basic configuration, when the friction of the speed reducer is large, or when the demand for adjustment accuracy is high, to eliminate the difference between the actual machine unit and the simulation unit, gravity and friction are required. Can be compensated. The motor control unit 11 has a built-in external force compensating unit 15 for gravity, static friction and dynamic friction of the mechanism unit 12, and calculates gravity torque and friction torque according to position feedback (hereinafter referred to as FB) to obtain torque. By adding to the command, the effect of external force is compensated. Alternatively, the control model unit 21 incorporates the gravity model of the motor model 23 and the external force compensating unit model 25 of the static friction and dynamic friction models, and calculates the gravitational torque and the friction torque according to the command, and adds them to the torque command. By doing so, the effect of external force may be simulated. Whether to enable the external force compensating unit 15 or the external force compensating unit model 25 is selected as necessary.
Similarly, when the control target is a robot having a plurality of links, a posture change occurs due to a normal operation command, so that the load inertia of each axis fluctuates in real time. Therefore, by having a model of the mechanism in advance, solving the dynamics calculation in real time, and obtaining the load inertia for each posture, the influence of the posture change is compensated when adjusting the control parameters.
Hereinafter, a method of adjusting the speed loop gain Kv and the position loop gain Kp of the motor control unit 11 will be described. Here, the adjustment operation is performed using a command during normal operation, but a special adjustment operation command may be used.
[0016]
(1) Preparation for adjustment
In the motor control unit 11 of the actual machine unit 10, Kp is set as an initial value of the position loop gain and the speed loop gain before adjustment.₀, Kv₀Set. In addition, the control model unit 21 of the simulation unit 20 also uses the same Kp as the initial values of the position loop gain and the speed loop gain as the actual machine unit 10.₀, Kv₀Set.
The position command at the time of the operation shown in FIG. 3A is input from the host controller to the motor control unit 11 of the real machine unit 10 and the control model unit 21 of the simulation unit 20. This command is, for example, a command to move from one point during the work to another point.
[0017]
(2) Adjustment of speed loop gain Kv
For the adjustment, a constant value section (steady state) of the position command is used, and the differential value of the position FB detected by the position detector 14 and the position detector model 24 connected to the motor 13 and the motor model 23 for this command ( The speed FB) is defined as a state quantity. The speed command and the speed FB of the real machine unit and the simulation unit have waveforms shown in FIG.
Here, when a response due to the frequency component of the command occurs, a response having the same frequency occurs at both the speed FB of the real machine unit and the speed FB of the simulation unit, and the influence of the frequency component caused by the command can be removed. .
The speed FB of the actual machine and the speed FB of the simulation are compared by the state quantity comparison unit 31, and a state quantity comparison value (difference of the speed FB) is created. It is determined whether or not the obtained state quantity comparison value is within a threshold value predetermined by the evaluation quantity calculation unit 32. Here, since the high-frequency vibration component is used as a criterion, an instantaneous value is used for the state quantity comparison.
[0018]
Speed loop gain Kv of actual machine₀Is too high than an appropriate value, the control system oscillates and the speed FB is oscillated by a high frequency component. Therefore, the value immediately before the high frequency component appears is the optimum value. Therefore, when the high-frequency component exceeds the threshold value, the speed loop gain Kv of the motor control unit 11 and the control model unit 21₀To a small value Kv₁, And repeat the adjustment. During the adjustment, the value immediately after the state becomes equal to or more than the threshold value from the state of being equal to or more than the threshold value is determined as the optimum value Kv.₂To end the adjustment.
Conversely, when there is no high-frequency component, the state quantity comparison value is equal to or less than the threshold value, but it cannot be determined whether the value is the optimum value. Therefore, the speed loop gain Kv of the actual machine gradually increases.₀To a large value Kv₁And the adjustment is repeated until a high-frequency component appears. During this adjustment, the value immediately before the value becomes equal to or more than the threshold value from the state within the threshold value is changed to the optimum value Kv.₂To end the adjustment.
By the above procedure, the optimum value of the speed loop gain Kv₂Can be requested.
[0019]
(3) Adjustment of position loop gain Kp
After adjusting the speed loop gain Kv, the position loop gain Kp is adjusted. For the adjustment, a position command constant speed section (steady state) shown in FIG. 4A is used, and the position detector 14 and the position detector model 24 connected to the motor 13 and the motor model 23 for this command detect the position command. The differential value (velocity FB) of the position FB thus obtained is defined as a state quantity. The speed command and the speed FB of the real machine section and the simulation section have waveforms shown in FIGS. 4B and 4C.
The speed FB of the actual machine and the speed FB of the simulation are compared by the state quantity comparison unit 31, and a state quantity comparison value (deviation of the speed FB) is created. It is determined whether or not the obtained state quantity comparison value is within a threshold value predetermined by the evaluation quantity calculation unit 32 and whether or not a high frequency component is present. An average comparison can be made by using the accumulated value for each fixed time as the state quantity comparison value.
[0020]
Position loop gain Kp of actual machine₀Is the value immediately before the high-frequency component appears. Position loop gain Kp of actual machine₀Is higher than the optimum value, the control system oscillates as shown in FIG. 4 (b), and the deviation of the speed FB is superimposed by the vibration of the high frequency component, and as shown in FIG. Is greater than the threshold. In this case, the position loop gain Kp of the motor control unit 11 and the control model unit 21₀To a small value Kp₁Reset to and repeat the adjustment. During the adjustment, the value immediately after the value becomes equal to or less than the threshold value from the state of being equal to or more than the threshold value is determined as the optimum value Kp.₂To end the adjustment.
Conversely, the position loop gain Kp of the actual machine₀Is smaller than the optimum value, no vibration of the high frequency component occurs as shown in FIG. 4C, but it cannot be determined whether or not the value is the optimum value. Further, since the deviation of the speed FB increases, the state quantity comparison value becomes larger than the threshold value as shown in FIG. In this case, the position loop gain Kp₀To a large value Kp₁, And the adjustment is repeated until the vibration of the high frequency component is obtained.₂To end the adjustment.
[0021]
The execution of these series of adjustment operations is performed by a method in which the operator operates the control device intentionally when the operator changes the load of the mechanical unit, or a specific method in the evaluation amount calculation unit 32 in advance. A method of monitoring the state quantity comparison value (such as the deviation of the speed FB between the real machine section and the simulation section), automatically detecting the fluctuation of the load inertia, and starting the control parameter adjustment work can be considered. Therefore, in the above-described embodiment, the configuration may be such that the deviation of the speed FB during normal operation is monitored, and when there is a difference between the state quantities of the actual machine unit and the simulation unit, the gain adjustment operation is automatically started. .
[0022]
Hereinafter, a second specific example of the present invention will be described.
This embodiment is different from the first embodiment in the process of determining the high-frequency component when adjusting the position loop gain and the speed loop gain. In the first embodiment, the extraction of the vibration component is obtained by directly measuring the time change of the waveform. However, in the present embodiment, the FFT (Fast Fourier Transform) is used by the state quantity comparison unit 31 to obtain the actual unit. And the vibration component of the position FB and the speed FB of the simulation unit can be determined more easily.
The determination of the vibration of the speed FB will be described as an example. By performing FFT analysis in the vibration component extraction unit 311 in the state comparison unit 31, a high frequency component is easily generated from the speed FB in FIGS. 5A and 5B as shown in FIG. 5C. Can be specified.
After that, according to the procedure described in the first specific example, the control parameter adjusting unit 33 controls the speed loop gain Kv and the speed loop gain Kv, which are the control parameters, so that the frequency and power of the real machine unit and the simulation unit substantially match within the threshold value. The position loop gain Kp is changed, and the process is repeated so that the state quantity comparison value falls within the threshold value.
[0023]
Hereinafter, a third specific example of the present invention will be described.
In this embodiment, after adjusting the control parameters of the motor control unit obtained in the first specific embodiment and performing the vibration characteristic evaluation, the motor control unit 11 of the real machine unit 10 and the simulation The control structure of the mechanism model unit 22 of the unit 20 is changed to improve the accuracy of adjustment.
If the vibration does not become smaller than the threshold in the vibration characteristic evaluation, it is determined that the order of the model to be controlled does not match, and the order of the mechanism model unit 22 of the simulation unit 20 is increased as shown in FIG. Change to the direction.
[0024]
Here, the control configuration is changed from a rigid body model (one inertial system) to a two inertial system model. However, when controlling an object to be controlled by the two inertia system, a spring element connecting the two inertia causes vibration, so that it is necessary to subtract a reaction force from the spring from a torque command of the motor control system. Therefore, the motor control unit 11 of the actual machine unit 10 arranges the observer of the two inertia model and sets the estimated torsion angle θ_SReaction force τ_RIs changed to a structure to subtract from the torque command. In the simulation unit 20, the torsion angle θ input to the secondary mechanism model 221 is set._SSReaction force τ_SIs subtracted from the torque command.
As described above, by changing the control configuration of the motor control unit 11 and the mechanism model unit 22 according to the adjustment result of the control parameter, vibration on the load side can be suppressed, and highly accurate control can be performed.
[0025]
Hereinafter, a fourth specific example of the present invention will be described. Here, a method for adjusting a control parameter of the interference force compensation based on the mutual inertia of the robot based on the trajectory deviation information between the real machine unit and the simulation unit will be described.
In the present embodiment, a method of adjusting a control system parameter for compensating mutual inertia will be described for a horizontal articulated robot to which a plurality of motors are connected. For the sake of simplicity, the mechanism to be controlled is a two-axis horizontal articulated robot as shown in FIG. Here, assuming that the main inertia of each axis (the load inertia JL of each axis) has already been determined, a method of adjusting the compensation parameter of the mutual inertia affecting other axes will be described.
In this embodiment, as shown in FIG. 8, a mutual interference compensator 35 is provided in the actual device. Mutual interference does not act on the simulation section, which is an ideal space. Therefore, if the mutual interference acting on the real machine section can be completely compensated by the mutual interference compensating section 35, the behavior becomes equivalent to that of the simulation section. Utilizing this, the position FB value of the robot tip of the real machine unit and the simulation unit in the orthogonal coordinate system is compared to reduce the position FB deviation, thereby adjusting the control parameter of the mutual interference compensation of the real machine unit. This will be described in detail below.
[0026]
(1) Mutual interference setting
The equation of motion of the two-axis horizontal articulated robot is expressed as follows.
[0027]
(Equation 1)

[0028]
Where m_iIs the mass of link i, L_iIs the distance from the axis to the center of gravity, a_iIs the link length. In addition, the term of the interference force related to the speed depends on the speed, changes slowly compared to the inertia term, and is compensated by the speed control loop. In that case, equations (1) and (2) can be expressed as follows.
[0029]
(Equation 2)

[0030]
Therefore, equations (3) and (4) can be expressed as follows.
[0031]
(Equation 3)

[0032]
here,
[0033]
(Equation 4)

[0034]
Also, I_iIs the moment of inertia around the center of gravity, N_iIs the reduction ratio of the reduction gear of the i-axis motor, I_imIs the inertia (equivalent moment of inertia) of the motor rotor of the motor.
m_i, L_i, A_i, N_iIs known and the main inertia J₁₁And J₂₂Is already determined as the load inertia JL, and therefore, the specific posture θ₁And θ₂Moment of inertia I around the center of gravity at_iFrom equations (6) to (8), and the mutual inertia J₁₂And J₂₁Can be requested.
[0035]
Equation (5) shows that the interference torque τ acting on the first axis during acceleration / deceleration₁₂And the interference torque τ on the first axis acting on the second axis₂₁Means that it can be expressed as follows.
[0036]
(Equation 5)

[0037]
Therefore, as shown in FIG.₁₂(= J₂₁), The mutual interference unit 35 is arranged in the actual machine unit 10.
[0038]
(2) Mutual inertia model parameter J₁₂Adjustment of
A position (angle) command during normal operation is input from the upper controller to the motor control units 11a and 11b of the real machine unit 10 and the control model units 21a and 21b of the simulation unit 20. As shown in FIG. 7 (b), this command sets the first axis to.₁And the second axis is θ₂, The interference force τ on the second axis₂₁And compare the behavior (trajectory shift) between the real machine section and the simulation section.
Mutual inertia J of the mutual interference compensator 35 of the actual machine_r12(= J_r21) And the mutual inertia J actually acting on the mechanism of the actual machine_s12(= J_s21) Do not match, a trajectory shift occurs between the real machine section and the simulation section. Here, the mutual inertia parameter of the mutual interference compensating unit 35 is adjusted by quantitatively determining the trajectory deviation between the real machine unit and the simulation unit.
[0039]
In order to compare the trajectories of the real machine section and the simulation section, in the forward conversion section 34, the position FB of the position detectors 14a and 14b of the motor control section 11 and the position detector models 24a and 24b of the control model section 21 Are forward-transformed, and the position FB (state quantity) of the robot tip of the real machine section and the simulation section in the orthogonal coordinate system is obtained. The state comparison section 31 obtains a state quantity comparison value by subtracting the two positions FB, and determines whether or not the difference is within a threshold value predetermined by the evaluation quantity calculation section 32.
If it is within the threshold value, the adjustment of the control parameter (mutual inertia) ends. This means that the mutual interference actually acting and the mutual interference compensator 35 of the actual machine have approximated values. If it is equal to or greater than the threshold value, the control parameter adjustment unit 33 controls the control parameter J of the mutual interference compensation unit 35 as shown below.₁₂And repeat until it is within the threshold.
[0040]
Mutual inertia parameter J₁₂As shown in FIG. 7 (b), the method of changing the parameter of the mutual inertia J is determined from the amount of deviation (ΔX, ΔY) between the trajectory of the real machine and the trajectory of the simulation section.₁₂Is determined with respect to the size of the change and the positive and negative directions. For this purpose, the deviation amount of the trajectory in the orthogonal coordinate system is converted into the deviation amount of the joint coordinate system using an inverse matrix of a minute displacement relational expression between the joint coordinate system and the working coordinate system called Jacobian. The biaxial Jacobian Jacobian can be represented by the following equation.
[0041]
(Equation 6)

[0042]
Where θ₁₂= Θ₁+ Θ₂
Also, its inverse matrix Jacobean^-1Can be represented by the following equation.
[0043]
(Equation 7)

[0044]
Therefore, the deviation amount (ΔX, ΔY) of the locus in the orthogonal coordinate system and the angle error (Δθ in the joint coordinate system)₁, Δθ₂) Can be expressed as:
[0045]
(Equation 8)

[0046]
Further, from the rigidity of the joint coordinate system, the relationship between the angle error and the torque can be expressed by the following equation.
[0047]
(Equation 9)

[0048]
Here, K = Kp · Kv · J
Therefore, the parameter J of the mutual inertia₁₂Can be obtained by solving the equation (13) and the following equation.
[0049]
(Equation 10)

[0050]
By repeating the above operation using the position command used in the actual operation, it is possible to adjust the control parameter of the interference force compensation due to the mutual interference of the multi-axis robot.
[0051]
【The invention's effect】
As described above, according to the motor control device of the first aspect, the real machine unit and the simulation unit are arranged in parallel, and the state quantities of the mechanical unit and the mechanical unit model are compared according to the same input command. Until the state quantity falls within a predetermined threshold, the operation parameter is changed by comparing the operation of the same command and changing the control parameter value of the actual machine unit, thereby limiting the operation area without being affected by gravity, dynamic friction, etc. The control parameters of the control unit can be automatically adjusted without any restrictions such as the above.
According to the motor control device of the second aspect, by performing the adjustment operation with a plurality of motor control state quantities, it is possible to adjust the control parameters generated between the axes in the case of a plurality of axes.
According to the motor control device of the third aspect, the gain adjustment of the motor control unit is performed so that the vibration characteristics of the speed and acceleration of the motor control unit are equal to or lower than a certain level as compared with the same signal of the simulation unit. By making the adjustment, the model parameters can be accurately identified irrespective of the operating conditions by judging the situation accurately.
According to the motor control device of the fourth aspect, the evaluation of the vibration characteristics uses a method of evaluating the magnitude of the vibration frequency component such as FFT, so that the problematic vibration components can be accurately determined, and the vibration characteristics can be accurately determined. The adjustment of the control parameters can be performed at the same time.
According to the motor control device of the fifth aspect, after the evaluation of the vibration characteristics, the control structure of the motor control unit is changed, thereby making it possible to construct a control system suitable for the mechanism configuration of the actual machine and the model. The target can be controlled more precisely.
According to the motor control device of the sixth aspect, the adjustment operation is terminated in accordance with the gain adjustment result using the instantaneous value or the accumulated value of the state quantity, thereby inadvertently changing the model parameters and the influence of noise. Can be prevented.
According to the motor control device of the present invention, the operator can update the control parameters according to the work content by selecting the execution of the adjustment operation according to the judgment of the operator or the evaluation amount calculation unit. Inadvertent change of control parameters can be prevented. In addition, parameters can be automatically updated.
According to the motor control device of the eighth aspect, by setting the control parameter of the motor control unit to a position loop gain or a speed loop gain, highly accurate positioning and speed response are possible.
According to the motor control device of the ninth aspect, the real machine unit and the simulation unit are arranged in parallel, and an external force compensating unit that compensates for an external force acting on the real machine unit, and the same state quantity of the real machine unit and the simulation unit And a compensation parameter adjusting section for adjusting the parameters of the external force compensating section, the external force compensating parameters of gravity and friction can be adjusted, and the accuracy of control parameter adjustment can be improved.
According to the motor control method of the tenth aspect, the real machine section and the simulation section are arranged in parallel, and the state quantities of the mechanism section and the mechanism section model are compared in accordance with the same input command, and are determined in advance. By changing the control parameter value of the real machine part from the operation by the same command until the state quantity falls within the threshold value, there are multiple peripheral devices around the mechanical part without being affected by gravity, dynamic friction, etc. Even in such a case, the control parameters of the control unit can be easily adjusted without any restrictions such as restrictions on the operation area.
According to the motor control method of the eleventh aspect, by compensating for mutual interference of the plurality of motors and adjusting the parameters of the mutual interference, the control parameters of the control unit can be automatically adjusted without being restricted by the mutual interference. Can be adjusted.
[Brief description of the drawings]
FIG. 1 is a first basic configuration diagram of the present invention.
FIG. 2 is a block diagram showing a first specific example of the present invention.
FIG. 3 is a response waveform 1 in the first specific example of the present invention.
FIG. 4 is a response waveform 2 in the first specific example of the present invention.
FIG. 5 is a response waveform in a second specific example of the present invention.
FIG. 6 is a block diagram showing a third specific example of the present invention.
FIG. 7 shows a model representing a fourth specific embodiment of the present invention.
FIG. 8 is a block diagram showing a fourth specific example of the present invention.
FIG. 9 is a diagram showing a conventional control method.
[Explanation of symbols]
10: Real machine section
11: Motor control unit
12: Mechanical unit
13: Motor
14: Position detector
15: External force compensator
20: Simulation section
21: Control model part
22: Mechanism model section
23: Motor model
24: Position detector model
25: External force compensator model
31: State quantity comparison unit
32: evaluation amount calculation unit
33: control parameter adjustment unit
34: Parameter identification unit
35: Mutual interference compensator
111: Position / velocity loop
112: Amplifier
121: secondary mechanism
122: reducer
211: Position / velocity control loop model
212: Amplifier model
221: Secondary mechanism model
222: Reduction gear model
311: vibration component extraction unit

Claims (11)

Driving a motor based on a command of a motor control unit, a motor control device having a drive mechanism unit connected to the motor,
A motor model simulating the motor, a mechanism model unit simulating the mechanism unit, and a simulation unit having a control model unit simulating the motor control unit;
A state quantity comparison unit that compares the same state quantity between the actual control unit and the simulation unit with the motor unit and the motor and the mechanism unit;
An evaluation amount calculation unit that creates an evaluation amount using the state amount,
A control parameter adjustment unit that adjusts a control parameter of the motor control unit so that the evaluation amount is adjusted to be within a predetermined value. The motor control device according to claim 1, wherein an adjustment operation is performed using the state quantities of a plurality of motors. The motor control device according to claim 1, wherein the control parameter adjustment unit adjusts based on a vibration characteristic of speed and acceleration of the motor control unit. 4. The motor control device according to claim 1, wherein the state quantity uses a vibration frequency component. The motor control device according to claim 1, wherein the control parameter adjustment unit changes a control structure of the motor control unit. 6. The motor control device according to claim 1, wherein the state quantity uses an instantaneous value or an accumulated value. 7. The motor control device according to claim 1, wherein the model parameter adjustment unit selects whether or not to perform the adjustment operation based on a determination of an operator or a result of the evaluation amount calculation unit. 8. The motor control device according to claim 1, wherein the control parameter of the motor control unit is a position loop gain or a speed loop gain. A motor control device that drives a motor based on a command from a motor control unit and has a mechanical unit connected to the motor.
A simulation unit having a motor model simulating the motor, a mechanism model unit simulating the mechanism unit, and a control model unit simulating the motor control unit;
An external force compensating unit that compensates for an external force acting on the actual machine unit,
A motor control device comprising: a compensation parameter adjusting unit that adjusts parameters of the external force compensating unit based on the same state quantity of the real machine unit and the simulation unit. Driving the motor based on a command of the motor control unit, in the method of controlling a motor having a mechanism connected to the motor,
A simulation unit that simulates a real machine unit including the motor control unit, the motor, and the mechanism unit,
Giving the same input to the real machine section and the simulation section,
Comparing the same state quantities of the real unit and the simulation unit,
A motor control method, comprising: adjusting a control parameter of the motor control unit. 11. The motor control method according to claim 10, wherein the mutual interference of the plurality of motors is compensated, and a parameter of the mutual interference is adjusted.

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