JP3647660B2 - Braking control device for numerical control device - Google Patents

Description

ここで、
制動エネルギ Ｅｔ［Ｊ］
モータイナーシャ Ｊｍ［ｋｇｍ² ］
モータ軸換算負荷イナーシャ ＪＬ［ｋｇｍ² ］
トータルイナーシャ（Ｊｍ＋ＪＬ） Ｊ［ｋｇｍ² ］
モータ軸換算摩擦トルク Ｔｄ［Ｎｍ］
Ｇ００指令の加減速時定数 ｔｌ［ｓｅｃ］
モータ回転数 Ｎ［ｍｉｎ^-1 ］
モータの内部インピーダンス Ｚｍ［Ω］
モータ電流 Ｉｍ［Ａ］
次に読み出したパートプログラムの全てのブロックの制動エネルギを数式（２）より積算する（Ｓ９）。
【００１１】
【数２】
ΣＥｔ(n)＝ΣＥｔ(n-1)＋Ｅｔ(n) ・・・（２）
ここで、
パートプログラムｎブロックの制動エネルギ Ｅｔ(n)［Ｊ］
【００１２】
一方、Ｓ２１ではＧ００指令以外の動作についての動作時間ｔ［ｓｅｃ］を算出する。主軸回転指令については加速度を予め決めておき指令回転数に応じて時間を算出する。工具自動交換時間については予め決められた時間とする。その他の補助動作についても時間を動作時間に合わせて決めておき指令に応じて決定する。
【００１３】
Ｓ６またはＳ２１で求めた軸移動時間または動作時間を数式（３）により積算する（Ｓ１０）。
【００１４】
【数３】
ΣＴ(n)＝ΣＴ(n-1)＋Ｔ(n) ・・・（３）
ここで、
パートプログラムｎブロックの動作時間 Ｔ(n)［ｓｅｃ］
【００１５】
次に、プログラムエンド（Ｍ０２）かどうか判定し、プログラムエンドであればＳ１２へ進み、プログラムエンドでなければＳ３よりの処理を繰り返す（Ｓ１１）。平均制動電力演算部６において、平均制動電力値Ｐｓを数式（４）より算出する（Ｓ１２）。
【００１６】
【数４】
Ｐｓ＝ΣＥｔ(n)／ΣＴ(n) ・・・（４）
ここで、
平均制動電力値 Ｐｓ［Ｗ］
【００１７】
制動電力比較部７は、パラメータメモリ２に予め設定された制動回路許容電力値Ｐａと平均制動電力値Ｐｓを比較し（Ｓ１３）、平均制動電力値Ｐｓの方が大きい場合は、一時停止時間演算部９において一時停止時間Ｔｓを数式（５）により算出して一時停止時間メモリ１０に記憶する（Ｓ１４）。
【数５】
Ｔｓ＝ΣＴ(n)・（Ｐｓ／Ｐａ）−ΣＴ(n) ・・・（５）
【００１８】
制動エネルギは数式（１）に示すようにモータ回転数の２乗に比例することにより、一般に
［Ｇ００指令の速度］＞［Ｇ０１指令の速度］
であるので、
［Ｇ００指令の制動エネルギ］＞＞［Ｇ０１指令の制動エネルギ］
が成り立つ。このため、実施形態１においては、Ｇ０１指令の制動エネルギはＧ００指令における制動エネルギに対して無視できる程度に小さいとした。しかし、近年のＧ０１指令の高速加工においては、Ｇ００指令における制動エネルギも考慮する必要がある。この場合は数式（１）を数式（６）に置き換えて対応可能である。尚、Ｎ(n)−Ｎ(n-1)≧０の場合は、力行状態となるため、Ｅｔ＝０とする。
【００１９】
【数６】

ここで、
パートプログラムnブロックのモータ回転数 Ｎ(n) ［ｍｉｎ^-1 ］
パートプログラムn-1ブロックのモータ回転数 Ｎ(n-1)［ｍｉｎ^-1 ］
Ｇ０１指令の加減速時定数 ｔ２［ｓｅｃ］
【００２０】
以上のようにして、制動回路の許容電力値と平均制動電力値から冷却に必要な最適一時停止時間が求められ、この一時停止時間は一時停止時間メモリ１０から読み出されて一時停止制御部１１により、必要な運転停止が行われる。本実施形態１においては、この運転一時停止は、パートプログラムの１ブロックずつで行われ、以下にその具体例を説明する。
図３は本発明の数値制御装置による１つのパートプログラム運転を示すものである。パートプログラム運転時において、関数発生部２１はパートプログラムメモリ４よりパートプログラムを１ブロックずつ読み出して実行する（Ｓ３１）。一時停止制御部１１は関数発生部２１が読み出したブロックがプログラムエンドかどうかを判定し（Ｓ３２）、プログラムエンドでなければＳ３１からの動作を繰り返す。プログラムエンドのときは一時停止時間メモリ１０よりそのパートプログラムに対応する一時停止時間を読み出し（Ｓ３３）、一時停止時間分ドゥエルを実行し、１つのパートプログラム運転を終了する。１つのパートプログラム終了後、次のパートプログラムを連続して実行するために従来技術であるスケジュールプログラム運転などで行うことができる。
【００２１】
さらに、主軸モータを含むシステムにおいても同様であり、この場合は数式（１）を数式（７）に変更して対応可能である。尚、Ｎ(n)−Ｎ(n-1)≧０の場合は、力行状態となるため、Ｅｔ＝０とする。
【数７】

【００２２】
図４は実施形態２のフローチャートの例である。Ｓ１からＳ３までは実施形態１と同様である。Ｓ４ではＧ００指令であればＳ５へ進み、Ｇ００指令でなければＳ２２に進む。Ｓ５からＳ１４までは実施形態１と同様である。Ｓ１２、Ｓ１３、Ｓ１４においては主軸モータについても別途実行する。
【００２３】
Ｓ２２では切削指令Ｇ０１指令であればＳ３１へ切削指令でなければＳ２３へ進む。Ｓ２３ではＭ０３、Ｍ０４、Ｍ０５、回転数指令であればＳ４１へ進み、主軸指令でなければＳ２１へ進み実施例１と同様の処理を行いＳ１０へ進む。
【００２４】
図５に示すＳ３１以下の処理は次の通りである。制動エネルギ演算部５は送り速度指令よりモータ速度を算出し（Ｓ３１）位置指令より軸移動時間を算出する（Ｓ３２）。前回の送り指令を呼び出し（Ｓ３３）、制動エネルギを数５に従って算出し（Ｓ３４）、今回の送り指令を記憶し（Ｓ３５）Ｓ９へ進む。
【００２５】
図６に示すＳ４１以下の処理は次の通りである。制動エネルギ演算部５は主軸の前回指令速度を呼び出し（Ｓ４１）、 動作時間の算出のため今回の指令速度との差より予め定められた加速減速の加速度に従って加速減速時間を算出し（Ｓ４２）、制動エネルギを数７により算出し（Ｓ４３）、制動エネルギを積算し（Ｓ４４）、今回の速度指令を記憶し（Ｓ４５）Ｓ１０へ進む。Ｓ１０においてはＳ６、Ｓ２１、Ｓ３２、Ｓ４２において算出した時間を積算する。同時動作がある場合は長い方のみを積算する。
【００２６】
【発明の効果】
パートプログラムの運転により制動回路が過熱することを予め認知するため、制動回路過熱により運転が中断することを防止する。
【図面の簡単な説明】
【図１】 本発明の実施形態１のブロック図である。
【図２】 本発明の実施形態１のフローチャートである。
【図３】 本発明の実施形態１のパートプログラム処理のフローチャートである。
【図４】 本発明の実施形態２のフローチャートである。
【図５】 図４に続くフローチャートである。
【図６】 図４に続くフローチャートである。
【図７】 従来技術のブロック図である。
【図８】 従来技術のフローチャートである。
【符号の説明】
１ パラメータ入力手段、２ パラメータメモリ、３ パートプログラム選択手段、４ パートプログラムメモリ、５ 制動エネルギ演算部、６ 平均制動電力演算部、７ 制動電力比較部、８ 表示部、９ 一時停止時間演算部、１０ 一時停止メモリ、１１ 一時停止制御部、２１ 関数発生部、２２ ドライブユニット、２３ 駆動モータ、２４ 制動回路過熱検出部、２５ 運転中断制御部。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a braking control device of a numerical control device.
[0002]
[Prior art]
2. Description of the Related Art A numerical control device is known which has a power generation braking circuit or a regenerative braking circuit provided in a drive unit of a drive motor, and this braking circuit is coupled to the drive motor to brake the drive shaft. In such a braking control device, depending on the part program to be operated, there is a problem that the braking circuit is overheated when the drive motor is vigorously accelerated or decelerated. For this reason, conventionally, a braking control device is provided with a braking circuit overheat detection unit that detects overheating of the braking circuit and an operation interruption control unit that interrupts operation when overheating, and the operation is interrupted when the braking circuit overheats. Yes.
[0003]
FIG. 7 is an example of a block diagram of the prior art. The function generator 21 reads the part program from the part program memory 4. According to the command code of the part program, in the case of an axis movement command code, a function is generated and a position command is generated, and in the case of a speed command code, a speed command is generated and commanded to the drive unit 22. The drive unit 22 drives the drive motor 23 according to the command.
[0004]
FIG. 8 is an example of a flowchart of the prior art. The braking circuit overheat detection unit 24 monitors the temperature of the braking circuit mounted on the drive unit 22 (S51). If overheating is detected, the process proceeds to S53 (S52). In S53, the function generation unit 21 is instructed to stop function generation (S53), the operation interruption control unit 25 is used to shut off the power supply of the power circuit of the drive unit 22 (S54), and the display unit 8 indicates that overheating has been detected. (S55).
[0005]
[Problems to be solved by the invention]
Normally, after the braking circuit is overheated, it cannot be operated until it is cooled, and it takes time to operate from the middle of the part program after cooling. In a machine tool that can automatically load and operate multiple different workpieces continuously, unattended operation may occur when the braking circuit is overheated due to part program operation of one workpiece and the operation is interrupted. It becomes difficult. Although it is possible to cope with overheating of the braking circuit by increasing the allowable power that can be handled, this causes a problem that the parts to be used increase in size and require a lot of space and cost.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned conventional problems, the present invention allows the numerical control device to calculate the average braking power in advance and is necessary for cooling the braking circuit when the average braking power is larger than the allowable power that can be processed by the braking circuit. A temporary stop time is obtained, the vehicle is temporarily stopped based on the pause time, and then the operation is resumed.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an example of a block diagram when the first embodiment of the present invention is applied to a numerical control device of an NC machine tool. The parameter input unit 1 can set the motor shaft conversion torque of the load inertia applied to the motor, which is a machine drive system parameter, and the friction of the machine sliding part, from the keyboard, and the set data is stored in the parameter memory 2. Yes. Further, the parameter memory 2 includes a motor inertia, a motor current, a motor internal impedance which are preset motor parameters, an acceleration / deceleration time constant which is a mechanical drive system parameter, a rapid traverse speed, and a braking which indicates a processing capacity of the braking circuit. A circuit allowable power value is stored. The part program memory 4 stores a part program similar to the conventional one to be operated.
[0008]
FIG. 2 is an example flowchart of the operation of the present invention.
The part program name input from the part program selection unit 3 is input to the braking energy calculation unit 5 (S1). The braking energy calculation unit 5 reads the corresponding part program from the part program 4 (S2), and reads one block of the read part program (S3). Then, it is determined whether or not the block is a G00 command. If it is a G00 command, the process proceeds to S5, and if it is not a G00 command, the process proceeds to S21 (S4).
[0009]
In the case of the G00 command, the number of revolutions reached is calculated from the rapid traverse speed, acceleration / deceleration time constant preset in the parameter memory 2 and the moving distance from the part program (S5). Further, the axis movement time t [sec] is calculated (S6). Next, a braking energy calculation parameter necessary for calculating the braking energy is read from the parameter memory 2 (S7). The braking energy calculation unit 5 calculates the braking energy from Equation (1) (S8).
[0010]
[Expression 1]

here,
Braking energy Et [J]
Motor inertia Jm [kgm ² ]
Motor shaft conversion load inertia JL [kgm ² ]
Total inertia (Jm + JL) J [kgm ² ]
Motor shaft equivalent friction torque Td [Nm]
G00 command acceleration / deceleration time constant tl [sec]
Motor rotation speed N [min ^-1 ]
Motor internal impedance Zm [Ω]
Motor current Im [A]
Next, the braking energy of all the blocks of the read part program is integrated from Equation (2) (S9).
[0011]
[Expression 2]
ΣEt (n) = ΣEt (n-1) + Et (n) (2)
here,
Part program n block braking energy Et (n) [J]
[0012]
On the other hand, in S21, an operation time t [sec] for operations other than the G00 command is calculated. For the spindle rotation command, the acceleration is determined in advance, and the time is calculated according to the command rotational speed. The automatic tool change time is a predetermined time. For other auxiliary operations, the time is determined according to the operation time and determined according to the command.
[0013]
The axis movement time or operation time obtained in S6 or S21 is integrated according to Equation (3) (S10).
[0014]
[Equation 3]
ΣT (n) = ΣT (n-1) + T (n) (3)
here,
Part program n block operation time T (n) [sec]
[0015]
Next, it is determined whether it is a program end (M02). If it is a program end, the process proceeds to S12. If it is not a program end, the processes from S3 are repeated (S11). The average braking power calculation unit 6 calculates the average braking power value Ps from Equation (4) (S12).
[0016]
[Expression 4]
Ps = ΣEt (n) / ΣT (n) (4)
here,
Average braking power value Ps [W]
[0017]
The braking power comparison unit 7 compares the braking circuit allowable power value Pa preset in the parameter memory 2 with the average braking power value Ps (S13). If the average braking power value Ps is larger, the temporary stop time calculation is performed. The unit 9 calculates the pause time Ts from the mathematical formula (5) and stores it in the pause time memory 10 (S14).
[Equation 5]
Ts = ΣT (n) · (Ps / Pa) −ΣT (n) (5)
[0018]
The braking energy is generally proportional to the square of the motor rotational speed as shown in Equation (1), so that generally [G00 command speed]> [G01 command speed]
So
[G00 command braking energy] >> [G01 command braking energy]
Holds. For this reason, in the first embodiment, the braking energy of the G01 command is determined to be negligible with respect to the braking energy of the G00 command. However, in recent high-speed machining of the G01 command, it is necessary to consider the braking energy in the G00 command. In this case, the formula (1) can be replaced by the formula (6). When N (n) −N (n−1) ≧ 0, a power running state is established, so Et = 0.
[0019]
[Formula 6]

here,
Motor speed of part program n block N (n) [min ^-1 ]
Motor speed of part program n-1 block N (n-1) [min ^-1 ]
G01 command acceleration / deceleration time constant t2 [sec]
[0020]
As described above, the optimum pause time required for cooling is obtained from the allowable power value and the average brake power value of the braking circuit, and this pause time is read from the pause time memory 10 and is temporarily stopped. Thus, the necessary operation stop is performed. In the first embodiment, the operation suspension is performed for each block of the part program, and a specific example thereof will be described below.
FIG. 3 shows one part program operation by the numerical control apparatus of the present invention. During the part program operation, the function generator 21 reads the part program from the part program memory 4 one block at a time and executes it (S31). The pause control unit 11 determines whether the block read by the function generation unit 21 is a program end (S32). If the block is not a program end, the operation from S31 is repeated. When the program ends, the pause time corresponding to the part program is read from the pause time memory 10 (S33), a dwell is executed for the pause time, and one part program operation is terminated. After the completion of one part program, it is possible to perform the schedule program operation, which is a conventional technique, in order to continuously execute the next part program.
[0021]
Further, the same applies to a system including a spindle motor. In this case, the formula (1) can be changed to the formula (7). When N (n) −N (n−1) ≧ 0, a power running state is established, so Et = 0.
[Expression 7]

[0022]
FIG. 4 is an example of a flowchart of the second embodiment. Steps S1 to S3 are the same as those in the first embodiment. In S4, if it is a G00 command, the process proceeds to S5, and if it is not a G00 command, the process proceeds to S22. S5 to S14 are the same as in the first embodiment. In S12, S13, and S14, the spindle motor is also separately executed.
[0023]
In S22, if it is a cutting command G01 command, the process proceeds to S31, and if not, the process proceeds to S23. In S23, if it is M03, M04, M05, and a rotational speed command, the process proceeds to S41, and if it is not a spindle command, the process proceeds to S21 and the same processing as in the first embodiment is performed, and the process proceeds to S10.
[0024]
The processes after S31 shown in FIG. 5 are as follows. The braking energy calculation unit 5 calculates the motor speed from the feed speed command (S31), and calculates the axis movement time from the position command (S32). The previous feed command is called (S33), the braking energy is calculated according to Equation 5 (S34), the current feed command is stored (S35), and the process proceeds to S9.
[0025]
The processing after S41 shown in FIG. 6 is as follows. The braking energy calculation unit 5 calls the previous command speed of the main spindle (S41), calculates the acceleration / deceleration time according to the acceleration / deceleration determined in advance from the difference from the current command speed to calculate the operation time (S42), The braking energy is calculated by Equation 7 (S43), the braking energy is integrated (S44), the current speed command is stored (S45), and the process proceeds to S10. In S10, the times calculated in S6, S21, S32, and S42 are integrated. If there is simultaneous operation, only the longer one is added.
[0026]
【The invention's effect】
Since it is recognized in advance that the braking circuit is overheated by the operation of the part program, the operation is prevented from being interrupted due to overheating of the braking circuit.
[Brief description of the drawings]
FIG. 1 is a block diagram of Embodiment 1 of the present invention.
FIG. 2 is a flowchart according to the first embodiment of the present invention.
FIG. 3 is a flowchart of part program processing according to the first embodiment of the present invention.
FIG. 4 is a flowchart of Embodiment 2 of the present invention.
FIG. 5 is a flowchart following FIG. 4;
FIG. 6 is a flowchart following FIG.
FIG. 7 is a block diagram of the prior art.
FIG. 8 is a flowchart of the prior art.
[Explanation of symbols]
1 parameter input means, 2 parameter memory, 3 part program selection means, 4 part program memory, 5 braking energy calculation section, 6 average braking power calculation section, 7 braking power comparison section, 8 display section, 9 pause time calculation section, DESCRIPTION OF SYMBOLS 10 Pause memory, 11 Pause control part, 21 Function generation part, 22 Drive unit, 23 Drive motor, 24 Braking circuit overheat detection part, 25 Operation interruption control part

Claims (2)

In a braking control device of a numerical control device, including a braking circuit that performs braking by converting kinetic energy of a motor driven according to a driving part program into electric braking energy,
Wherein greater than processable allowable power value of the average control power value calculated in advance based on the contents of the part program the brake circuit for operation, the pause seeking pause time required for cooling of the braking circuit time calculation And
A pause control unit that pauses the operation and then resumes the operation based on the pause time;
A braking control device for a numerical control device, comprising: A part program memory for storing a part program, a function generation unit for generating a position command or a speed command by the part program, and a drive unit for driving the motor by a command from the function generation unit to convert the kinetic energy of the motor into electric braking energy In a braking control device of a numerical control device including a braking circuit that performs braking by conversion, an overheat detection unit that detects overheating of the braking circuit, and an operation interruption control unit that interrupts operation when overheated, motor inertia and motor current A braking energy calculation parameter comprising a motor drive parameter comprising a motor shaft equivalent torque and acceleration / deceleration time constant of a load inertia connected to the motor and a friction of a machine sliding part and a motor shaft equivalent torque, and the braking circuit A parameter that stores the braking circuit allowable power value indicating Data memory, a part program selection unit for selecting a part program stored in advance in the part program memory, and reading out the selected part program and analyzing the motor rotation command and the braking analyzed from the contents of the part program in each row A braking energy calculator that calculates braking energy and operating time from energy calculation parameters; an average braking power calculator that calculates an average braking power value obtained by dividing the total braking energy calculated from each line of the part program by the total driving time; When the average braking power value is large by comparing the average braking power value with the preset braking circuit allowable power value, driving is performed from the product of the value obtained by dividing the average braking power value by the braking allowable power value and the driving time. Pause time calculator that calculates the pause time by subtracting the time, and the calculated pause A numerical value control device comprising: a pause time memory for storing a pause; and a pause control unit that pauses for the pause time stored at the end of operation of the part program and resumes operation after the time has elapsed. Braking control device.

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