JP7002072B2 - Numerical control device and control method - Google Patents

Description

The present invention relates to a numerical control device and a control method.

Patent Document 1 proposes a method for controlling a machine tool that suppresses vibration by setting the acceleration / deceleration time to the reciprocal of the machine vibration. This method has a problem that vibration of only one frequency and a frequency that is an integral multiple of the frequency can be suppressed. On the other hand, there is a method of suppressing vibration by using a moving average filter having a time constant of the reciprocal of mechanical vibration. In this method, by applying a plurality of moving average filters having different time constants in an overlapping manner, it is possible to suppress vibration against mechanical vibrations of a plurality of frequencies.

Japanese Unexamined Patent Publication No. 54-98477

The frequency of machine vibration fluctuates due to variations in the manufacturing process of the machine, changes in the load weight of the machine, and the like. Since the above method performs vibration control for a specific frequency, if the frequency of mechanical vibration fluctuates, vibration control cannot be performed effectively, and there is a possibility that the processing quality may deteriorate.

An object of the present invention is to provide a numerical control device and a control method capable of effectively suppressing vibration even if the frequency of mechanical vibration fluctuates.

The numerical control device according to claim 1 calculates and applies a change in acceleration or speed with respect to a time axis based on a given acceleration / deceleration pattern to a speed command or a position command of a servomotor that drives a machine. In a numerical control device provided with an acceleration / deceleration control unit that controls acceleration / deceleration of a servomotor, the acceleration / deceleration pattern is a two-stage convex acceleration / deceleration in which the acceleration or velocity increases in a convex manner in the central portion of the time axis. The pattern indicates the change in the acceleration with respect to the time axis when applied to the speed command, and indicates the change in the speed with respect to the time axis when applied to the position command. Therefore , the acceleration / deceleration control unit has a reception unit that receives input of range information indicating a range of frequencies that suppress the vibration of the machine, and a convex acceleration / deceleration pattern based on the range information received by the reception unit. The convexity is based on a calculation unit that calculates the ratio between the magnitude of the acceleration or velocity in the first stage and the magnitude of the acceleration or velocity in the second stage that is larger than the first stage, and the ratio calculated by the calculation unit. It is characterized by including a setting unit for setting the size of each of the first stage and the second stage of the mold acceleration / deceleration pattern. The acceleration / deceleration control unit of the numerical control device controls the acceleration / deceleration of the servomotor based on the convex acceleration / deceleration pattern that has a convex acceleration or speed instead of the conventional moving average for the speed command or position command. conduct. Therefore, the numerical control device can suppress vibration within a certain range. Since the numerical control device can easily optimize the range of vibration suppression of the machine by the range information input by the operator, it is the optimum convex type according to the expected variation in the manufacturing process of the machine and the change of the integrated mass. Acceleration / deceleration patterns can be designed. By applying the convex acceleration / deceleration patterns in an overlapping manner, it is possible to give a vibration damping effect to a plurality of frequency ranges.

In the numerical control device of claim 2, when the period of the central portion of the convex acceleration / deceleration pattern is Tn, which is the reciprocal of the median of the frequency range to be _damped , the convex acceleration / deceleration pattern. By setting the period of each of the front side portion, which is the front side of the central portion, and the rear side portion, which is the rear side, to _Tn / 2, the vibration damping effect can be obtained around the median value of the vibration damping frequency. It can have a certain range. Therefore, the numerical control device can design a convex acceleration / deceleration pattern capable of controlling vibration within a range having a certain width.

In the numerical control device of claim 3, when the magnitude of the acceleration or velocity of the first stage of the convex acceleration / deceleration pattern is a and the magnitude of the acceleration or velocity of the second stage is b, a. It is good that ≠ b. The numerical control device has a range in which the vibration damping effect is obtained by adjusting the ratio after making the magnitude a of the acceleration or velocity of the first stage and the magnitude b of the acceleration or velocity of the second stage different from each other. Can be changed. Therefore, the numerical control device can design the optimum convex acceleration / deceleration pattern according to the expected variation in the manufacturing process of the machine and the change in the integrated mass.

The acceleration / deceleration control unit of the numerical control device according to claim 4 has a filter corresponding to the convex acceleration / deceleration pattern, and the filter processes the speed command or the position command to obtain the servomotor. The acceleration / deceleration control may be performed. The acceleration / deceleration control unit can realize the convex acceleration / deceleration pattern by processing the speed command or the position command with the filter, so that the acceleration / deceleration control can be performed easily and quickly.

であって、前記フィルタで、前記速度指令又は前記位置指令を処理したときに前記制振する周波数の範囲で振動が０になる周波数と、当該範囲の中心周波数との比率をαとしたとき、Ｋ＝－ＣＯＳ（απ）であるとよい。それ故、数値制御装置は、機械の振動特性に応じてＴ_ｎを決定し、制振する範囲に応じてαを決定することによって、適切なフィルタを設計できる。 In the numerical control device of claim 5, the filter has a rectangular first filter having the acceleration or velocity magnitude a in the first stage, and the acceleration or velocity magnitude b in the second stage. Assuming a convex filter expressed by adding a rectangular second filter, the period of the central portion of the convex acceleration / deceleration pattern is the reciprocal of the central value of the frequency range to be suppressed. When the ratio of _n , a and b is K, and the area of the convex filter is Laplace-transformed and the equation established by _Tn and K is F (s),

When the ratio of the frequency at which the vibration becomes 0 in the frequency range of the vibration damping frequency when the speed command or the position command is processed by the filter and the center frequency of the range is α. It is preferable that K = −COS (απ). Therefore, the numerical control device can design an appropriate filter by determining _Tn according to the vibration characteristics of the machine and determining α according to the vibration damping range.

The control method according to claim 6 is to process the acceleration or the magnitude of the speed with respect to the time axis based on a given acceleration / deceleration pattern with respect to the speed command or the position command of the servomotor that drives the machine. In the control method of the numerical control device provided with the acceleration / deceleration control step for controlling the acceleration / deceleration of the motor, the acceleration / deceleration pattern is a two-stage convex type in which the acceleration or the velocity is convexly increased in the central portion of the time axis. When the acceleration / deceleration pattern is applied to the speed command, the change in the acceleration with respect to the time axis is shown, and when applied to the position command, the change in the speed with respect to the time axis is shown. The acceleration / deceleration control step includes a reception step that accepts input of range information indicating a range of frequencies that suppress the vibration of the machine centering on the natural frequency of the machine, and the range that is received in the reception step. Based on the information, the calculation step of calculating the ratio between the magnitude of the acceleration or velocity of the first stage in the convex acceleration / deceleration pattern and the magnitude of the acceleration or velocity of the second stage larger than the first stage, and the calculation. Based on the ratio calculated in the step, the convex acceleration / deceleration pattern is characterized by including a setting step for setting the size of each of the first stage and the second stage. Since the numerical control device performs the above control step, the effect according to claim 1 can be obtained.

The inventions of claim 1-5 described above can be arbitrarily combined. For example, not all or part of claim 1 may be provided, but at least one of the other claims 2-5 may be provided. However, in particular, it is preferable to include the configuration of claim 1 and to include at least one configuration and combination of claim 2-5. Any component of claim 1-5 may be extracted and combined. The applicant intends to obtain a patent right for such a structure.

The block diagram which shows the electric composition of a numerical control device 20 and a machine tool 10. Flow chart of main processing. The figure which shows the convex acceleration / deceleration filter. The image figure which expressed the convex acceleration / deceleration filter by adding filters A1 and A2. The figure which shows the convex acceleration / deceleration filter (K = 0.95). The board diagram which shows the frequency response of the convex acceleration / deceleration filter shown in FIG. The figure which shows the convex acceleration / deceleration filter (K = 0.3). The board diagram which shows the frequency response of the convex acceleration / deceleration filter shown in FIG. 7. The board diagram which shows the frequency response of the convex acceleration / deceleration filter of K = 0.809. The board diagram which shows the frequency response of the convex acceleration / deceleration filter of K = 0.309. A chart showing the velocity pattern processed by the convex acceleration / deceleration filter. A chart showing the acceleration pattern processed by the convex acceleration / deceleration filter. Flow chart of filter setting process. Diagram of the movement path used in the simulation. Bode diagram comparing the frequency response of the conventional filter and the convex acceleration / deceleration filter. The chart which analyzed the natural vibration (40Hz) of the table. The chart which analyzed the natural vibration (42.5Hz) of the table. The chart which analyzed the natural vibration (45Hz) of the table. The chart which analyzed the natural vibration (47.5Hz) of the table. The chart which analyzed the natural vibration (50Hz) of a table. A Bode diagram showing the frequency response of a convex acceleration / deceleration filter in which a positive value is set for K. A chart showing an acceleration pattern processed by a convex acceleration / deceleration filter in which a positive value is set for K. A Bode diagram showing the frequency response of a convex acceleration / deceleration filter in which a negative value is set for K. A chart showing an acceleration pattern processed by a convex acceleration / deceleration filter in which a negative value is set for K.

An embodiment of the present invention will be described. The numerical control device 20 shown in FIG. 1 controls the operation of the machine tool 10 to cut a work material (not shown) held on the upper surface of a table (not shown). The left-right direction, the front-back direction, and the up-down direction of the machine tool 10 are the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively.

The configuration of the machine tool 10 will be described with reference to FIG. The machine tool 10 moves, for example, a tool mounted on a spindle extending in the Z-axis direction in the X-axis direction, the Y-axis direction, and the Z-axis direction with respect to the work material held on the upper surface of the table (for example, drilling, tapping). It is a vertical machine tool that performs machining, side machining, etc.). The machine tool 10 includes a spindle mechanism (not shown), a spindle moving mechanism, a tool changing device, and the like. The spindle mechanism includes a spindle motor 12 and rotates a spindle equipped with a tool. The spindle moving mechanism further includes a Z-axis motor 11, an X-axis motor 13, and a Y-axis motor 14, and the spindle is relatively oriented toward each feed axis of XYZ with respect to the work material supported on the upper surface of the table (not shown). Move each. The tool changer includes a magazine motor 15, drives a tool magazine (not shown) for storing a plurality of tools, and exchanges a tool mounted on the spindle with another tool. The Z-axis motor 11, the spindle motor 12, the X-axis motor 13, the Y-axis motor 14, and the magazine motor 15 are servo motors. In this embodiment, the Z-axis motor 11, the spindle motor 12, the X-axis motor 13, the Y-axis motor 14, and the magazine motor 15 are collectively referred to as motors 11 to 15.

The machine tool 10 further includes an operation panel 16. The operation panel 16 includes an input unit 17 and a display unit 18. The input unit 17 is a device for performing various inputs, instructions, settings, and the like. The display unit 18 is a device that displays various screens. The operation panel 16 is connected to the input / output unit 25 of the numerical control device 20. The Z-axis motor 11 includes an encoder 11A. The spindle motor 12 includes an encoder 12A. The X-axis motor 13 includes an encoder 13A. The Y-axis motor 14 includes an encoder 14A. The magazine motor 15 includes an encoder 15A. The encoders 11A to 15A are connected to the drive circuits 26 to 30 described later of the numerical control device 20, respectively.

The electrical configuration of the numerical control device 20 will be described. The numerical control device 20 includes a CPU 21, a ROM 22, a RAM 23, a storage device 24, an input / output unit 25, drive circuits 26 to 30, and the like. The CPU 21 controls the numerical control device 20 in an integrated manner. The ROM 22 stores various programs such as a main program and a filter setting program. The main program is a program for executing the main processing (see FIG. 2) described later. The filter setting program is a program for executing the filter setting process (see FIG. 13) described later. The RAM 23 stores various data during various processes. The storage device 24 is a non-volatile memory, and stores various data in addition to an NC program for processing, for example. The input / output unit 25 is connected to the operation panel 16. The drive circuits 26 to 30 are servo amplifiers. The drive circuit 26 is connected to the Z-axis motor 11 and the encoder 11A. The drive circuit 27 is connected to the spindle motor 12 and the encoder 12A. The drive circuit 28 is connected to the X-axis motor 13 and the encoder 13A. The drive circuit 29 is connected to the Y-axis motor 14 and the encoder 14A. The drive circuit 30 is connected to the magazine motor 15 and the encoder 15A.

The CPU 21 interprets an NC program for machining a work material, and issues a control command for moving each drive axis such as a feed axis (X axis, Y axis, Z axis), a spindle axis, and a magazine axis to a target position. It is transmitted to the drive circuits 26 to 30. The drive circuits 26 to 30 output drive currents (pulses) to the corresponding motors 11 to 15 in response to the control commands (drive signals) received from the CPU 21. The drive circuits 26 to 30 receive feedback signals (position and speed signals) from the encoders 11A to 15A, and control the position and speed of the motors 11 to 15. The drive circuits 26 to 30 are servo amplifiers that drive the servo motor, and may be configured by, for example, an FPGA circuit.

The main process will be described with reference to FIG. The operator selects one NC program from a plurality of NC programs stored in the storage device 24 by using the input unit 17 of the operation panel 16, and instructs the start of machining of the work material based on the selected NC program. .. When the CPU 21 receives the machining start instruction from the input unit 17, the CPU 21 reads the main program stored in the ROM 22 and executes this process.

The CPU 21 reads the NC program selected by the input unit 17 and interprets one line (S1). The CPU 21 determines whether or not the interpreted control command in one line is the end command (M30) (S2). If the interpreted control command is not an end command (S2: NO), the CPU 21 generates an internal command based on the interpretation of the control command (S3). The CPU 21 determines whether or not the generated internal command is a speed command (S4). When the generated internal command is not a speed command (S4: NO), the CPU 21 executes an operation based on the generated internal command (S7). The CPU 21 returns to S1 and interprets the next line of the NC program. When the internal command is the speed command of the feed shaft (S4: YES), the CPU 21 performs acceleration / deceleration processing on the speed command in order to suppress the vibration generated during the movement of the feed shaft (S5).

In the acceleration / deceleration process, the CPU 21 processes the generated speed command using a convex acceleration / deceleration filter (see FIG. 3) described later. As a result, the CPU 21 can remove the vibration component in a specific frequency range from the speed command. Therefore, since the numerical control device 20 can suppress vibration in a specific frequency range, it can effectively suppress vibration even if the vibration frequency peculiar to the machine fluctuates due to a change in the load mass on the table. The data of the convex acceleration / deceleration filter is stored in, for example, the storage device 24. Details of the convex acceleration / deceleration filter will be described later. The CPU 21 outputs a drive current (pulse) to the drive circuit of the corresponding servomotor to drive the feed shaft based on the speed command processed by the convex acceleration / deceleration filter (S6). The CPU 21 returns to S1 and interprets the next line. When the interpreted command is an end command (S2: YES), the CPU 21 ends the main process.

The features of the convex acceleration / deceleration filter will be described with reference to FIG. The convex acceleration / deceleration filter is, for example, an FIR (Finite Impulse Response) filter. The convex acceleration / deceleration filter can be applied to the speed command or the position command. When the convex acceleration / deceleration filter is applied to the velocity command, the time change of acceleration becomes convex. When the convex acceleration / deceleration filter is applied to the position command, the time change of the velocity becomes convex. In other words, the convex acceleration / deceleration filter is a digital filter designed to have a two-stage acceleration / deceleration pattern in which the acceleration or speed increases convexly in the central part of the time axis when applied to the speed command or the position command. Is. The acceleration / deceleration pattern means a time change of acceleration or velocity. This embodiment describes a case where the convex acceleration / deceleration filter is applied to the speed command.

The convex acceleration / deceleration filter calculates the time change of acceleration from the velocity command. In the chart of FIG. 3, the horizontal axis shows time (seconds), and the vertical axis shows gain. The convex acceleration / deceleration filter is a two-stage convex filter in which the gain increases convexly in the central portion of the time axis. The convex acceleration / deceleration filter has three regions, a front side portion 31, a central portion 32, and a rear side portion 33. The central portion 32 is a central portion on the time axis and is a region where acceleration or velocity is convexly large. The front side portion 31 is a region on the front side of the central portion 32. The rear side portion 33 is a region behind the central portion 32.

When the period of the median value of the frequency range for damping is T _n , the period of the central portion 32 is T _n . The cycle of each of the front side portion 31 and the rear side portion 33 is T _n / 2. The height of each of the front side portion 31 and the rear side portion 33 is a, and the height of the central portion is b. The heights of the front side portion 31 and the rear side portion 33 are the same. b is larger than a. The center frequency of the frequency range in which the convex acceleration / deceleration filter removes the vibration component is 1 / _Tn . The convex acceleration / deceleration filter of the present embodiment can easily and appropriately adjust the range of the vibration damping effect by adjusting the ratio of a and b. In this embodiment, in order to make it possible to easily design a convex acceleration / deceleration filter by inputting parameters to the numerical control device 20, a mathematical expression of the convex acceleration / deceleration filter has been studied.

With reference to FIG. 4, a method of deriving a mathematical formula expressing the convex acceleration / deceleration filter will be described. As shown in FIG. 4, in the present embodiment, it is considered that the convex acceleration / deceleration filter is represented by the sum of two rectangular filters A1 and A2. Both the filters A1 and A2 are rectangular filters in which an impulse response is set with respect to the time axis. The filter A1 has a horizontally long rectangular shape. The filter A2 has a rectangular shape having a narrower width than the filter A1. When the cycle length of the filter A1 is 2T _n , the cycle length of the filter A2 is T _n . The filter A2 lags the filter A1 by _Tn / 2 hours. A convex filter is expressed by adding the above filters A1 and A2.

Ｆ（ｓ）は、凸型加減速フィルタの全体の面積を示している。Ｆ（ｓ）の中括弧内の前段部分はフィルタＡ１の面積を示し、後段部分はフィルタＡ２の面積を示している。フィルタＡ１の面積は２Ｔ_ｎであるが、それを２Ｔ_ｎで割ることによって１にしている。これに対し、フィルタＡ２の面積をＫとする。Ｋは、フィルタＡ１の面積に対するＡ２の面積の比率を示している。Ｆ（ｓ）は、Ｔ_ｎとＫの変数によって成り立つ式である。中括弧内の後段部分中の「－Ｔ_ｎ／２」は、フィルタＡ２がＡ１に対して、Ｔ_ｎ／２の遅れがあることを示している。中括弧内の面積は、１＋Ｋとなり、それを（１＋Ｋ）で割ることによって、凸型加減速フィルタの面積は最終的に１にしている。故に凸型加減速フィルタの入力量と出力量は変わらないので、本実施形態は、凸型加減速フィルタの処理の前後で、送り軸の移動量が同一となるように制御できる。Ｋ＝１のとき、フィルタＡ１とＡ２の夫々の面積は等しい。 In this embodiment, based on the above filters A1 and A2, the Laplace transform of the convex acceleration / deceleration filter is performed, and the definition is as follows.

F (s) indicates the total area of the convex acceleration / deceleration filter. The front part in the curly braces of F (s) shows the area of the filter A1, and the rear part shows the area of the filter A2. The area of the filter A1 is _2Tn , but it is divided by _2Tn to make it 1. On the other hand, the area of the filter A2 is K. K indicates the ratio of the area of A2 to the area of filter A1. F (s) is an expression that holds for the variables T _n and K. "-T _n / 2" in the latter part in the curly braces indicates that the filter A2 has a delay of T _n / 2 with respect to A1. The area inside the curly braces is 1 + K, and by dividing it by (1 + K), the area of the convex acceleration / deceleration filter is finally set to 1. Therefore, since the input amount and the output amount of the convex acceleration / deceleration filter do not change, the present embodiment can be controlled so that the movement amount of the feed shaft is the same before and after the processing of the convex acceleration / deceleration filter. When K = 1, the areas of the filters A1 and A2 are equal.

Ｋは、凸型加減速フィルタの一段目（前側部３１及び後側部３３）の高さａと、二段目（中央部３２）の高さｂの比率を調整するパラメータである。このとき、ａは、以下の数３で算出できる。

Next, when the number 1 is rearranged, the convex acceleration / deceleration filter becomes the following number 2.

K is a parameter for adjusting the ratio of the height a of the first stage (front side portion 31 and the rear side portion 33) of the convex acceleration / deceleration filter to the height b of the second stage (central portion 32). At this time, a can be calculated by the following number 3.

故に凸型加減速フィルタを設計する為のａとｂは、上記数３と数４に、ＫとＴ_ｎを代入することによって夫々算出できるものとなった。 Since b is (a + b) T _n = 1, it can be calculated by the following number 4 which is modified by substituting it into the number 3.

Therefore, a and b for designing the convex acceleration / deceleration filter can be calculated by substituting K and _Tn into the above equations 3 and 4, respectively.

The frequency response of the convex acceleration / deceleration filter will be described with reference to FIGS. 5 to 8. The frequency response of the convex acceleration / deceleration filter is important in determining the range of frequencies to be damped. FIG. 5 shows a convex acceleration / deceleration filter with K = 0.95 and Tn ₌ 2, and FIG. 6 shows the frequency response of the acceleration of the convex acceleration / deceleration filter with K = 0.95 and Tn ₌ 2. ing. The frequency response indicates the force for each frequency of the signal processed by the convex acceleration / deceleration filter in terms of Magnitude (or gain). The horizontal axis of the Bode diagram of FIG. 6 shows the frequency (Hz), and the vertical axis shows the absolute value of the magnitude of the frequency response. As shown in FIG. 5, the convex acceleration / deceleration filter with K = 0.95 has a larger difference between a and b than the convex acceleration / deceleration filter with K = 0.3 (see FIG. 7) described later. Therefore, the central portion 32 protrudes greatly upward with respect to the front side portion 31 and the rear side portion 33.

As shown in FIG. 6, the frequency response of the convex acceleration / deceleration filter with K = 0.95 is small in the range of 0.4 to 0.6 (Hz) centered on 0.5 (Hz). .. The range in which the frequency response is small is the range in which the damping effect is effective (hereinafter referred to as "vibration damping range"). The frequency response becomes 0 in the vibration suppression range at 0.5 (Hz), which is the center of the vibration suppression range, and 0.4 (Hz) and 0.6 (Hz), which are frequencies before and after the center of the vibration suppression range. Between 0.4 and 0.5 and between 0.5 and 0.6, the frequency response is slightly bulging in a chevron shape. In the frequency response of the convex acceleration / deceleration filter with K = 0.95, the vibration suppression range is narrower than the frequency response with K = 0.3 (see FIG. 8) described later, but the frequency response within the vibration suppression range is narrow. The mountains are small. From this, it can be seen that the damping effect of the convex acceleration / deceleration filter with K = 0.95 in the damping range is higher than that with the convex acceleration / deceleration filter with K = 0.3.

FIG. 7 is a convex acceleration / deceleration filter with K = 0.3, and FIG. 8 shows the frequency response of the acceleration of the convex acceleration / deceleration filter with K = 0.3 and _{Tn =} 2. As shown in FIG. 7, the convex acceleration / deceleration filter with K = 0.3 has a smaller difference between a and b than the above-mentioned convex acceleration / deceleration filter with K = 0.95. As shown in FIG. 8, the frequency response of the convex acceleration / deceleration filter with K = 0.3 is small in the range of 0.32 to 0.68 (Hz) centered on 0.5 (Hz). .. The frequency response becomes 0 in the vibration suppression range at 0.5 (Hz), which is the center of the vibration suppression range, and 0.32 (Hz) and 0.68 (Hz), which are the frequencies before and after that. Between 0.32 and 0.5 and between 0.5 and 0.68, the frequency response swells greatly upward in a chevron shape as compared with the frequency response shown in FIG. In the frequency response of the convex acceleration / deceleration filter with K = 0.3, the vibration suppression range is wider than the frequency response with K = 0.95 described above (see FIG. 6), but the frequency response within the vibration suppression range is wide. The mountain is big. This means that the frequency component within the vibration damping range included in the speed command cannot be sufficiently removed, and acceleration / deceleration may cause vibration in the machine to affect machining. However, if the frequency range in which the machine is prone to vibration is wider than the range of 0.4 to 0.6 (Hz) covered by K = 0.95, a convex type with K = 0.3 when considered comprehensively. It can be said that the vibration damping effect is higher than that of the acceleration / deceleration filter.

From the above, it can be seen that the damping range of the frequency response of the convex acceleration / deceleration filter changes depending on K. Therefore, the numerical control device 20 can easily adjust the vibration damping range by the convex acceleration / deceleration filter by adjusting K.

The design method of the parameter K will be described with reference to FIGS. 9 to 11. As described above, K is an important factor that defines a and b of the convex acceleration / deceleration filter. In order to obtain the frequency transfer function of F (s), s of the above number 2 is set to jω, and e ^ -jω = cosω-jsinω is substituted and arranged. Can be transformed into. The front part in the brackets is the real part R (ω), and the rear part is the imaginary part I (ω).

上記の数５と数６から、Ａ（ω）は以下の数７に変形できる。

Next, for example, in the Bode diagram as shown in FIGS. 6 and 8, the following number 6 in which the gain of the frequency response is A (ω) and A (ω) = 0 is considered.

From the above number 5 and number 6, A (ω) can be transformed into the following number 7.

ω_ｚｅｒｏを、制振範囲の中心の角周波数ω_ｎ＝２π／Ｔ_ｎと、それに対する比率αを用いて以下の数１０のように表すことが出来る。
［数１０］
ω_ｚｅｒｏ＝（２π／Ｔ_ｎ）×α
上記の通り、ω_ｎは、制振範囲の中心周波数であり、数７より周波数応答が０となる周波数である。故に上記の数９に数１０を代入することにより、パラメータＫは、以下の数１１のように表すことができる。
［数１１］
Ｋ＝－ＣＯＳ（απ） Since A (ω) = 0, K is obtained so that the underlined portion in the route of the above equation 7 becomes 0. That is, by controlling K, the frequency ω at which the frequency response becomes 0 can be determined. The ω in which the underlined portion of the equation 7 is 0 is ω _zero in FIGS. 9 and 10. As shown in the following equations 8 and 9, K is calculated from ω _zero .

ω _zero can be expressed as the following equation tens using the angular frequency ω _n = 2π / T _n at the center of the damping range and the ratio α to it.
[Number 10]
ω _zero = (2π / T _n ) × α
As described above, ω _n is the center frequency of the vibration damping range, and is a frequency at which the frequency response becomes 0 from Equation 7. Therefore, by substituting the number 10 into the above number 9, the parameter K can be expressed as the following number 11.
[Number 11]
K = -COS (απ)

The parameter K can be calculated by substituting α into the above number 11. As described above, α is the ratio of ω _zero to ω _n , so that the operator can change the vibration characteristics of the machine tool 10 and the assumed variation in the manufacturing process of the machine tool 10 and the load mass. ω _zero and ω _n may be determined. The vibration characteristics of the machine tool 10 may be obtained from an experiment such as an operation analysis of the machine tool 10.

A calculation example 1 of the parameter K will be described with reference to FIG. The frequency characteristics shown in FIG. 9 show a frequency response of T _n = 2 (sec) and ω _n = 0.5 (Hz). The convex acceleration / deceleration filter having this frequency response characteristic can suppress the frequency response in the range of 0.4 to 0.6 (Hz) centered on 0.5 (Hz). Since ω _n = 0.5 and ω _zero = 0.4 and 0.6, α = 0.8 or 1.2. Substituting into the above number 11, K = 0.809.

The calculation example 2 of the parameter K will be described with reference to FIG. The frequency characteristics shown in FIG. 10 show a frequency response of T _n = 2 (sec) and ω _n = 0.5 (Hz). The convex acceleration / deceleration filter having this frequency response characteristic can suppress the frequency response in the range of 0.3 to 0.7 (Hz) centered on 0.5 (Hz). Since ω _zero = 0.3 and 0.7, α = 0.6 or 1.4. Substituting into the above number 11, K = 0.309. From the above, K changes according to the magnitude of α, which is the ratio of ω _zero and ω _n . The larger α is, the larger K is, and the smaller α is, the smaller K is.

As shown in FIGS. 9 and 10, the vibration damping range centered on ω _n should be set to the optimum range according to the assumed variation in the manufacturing process of the machine tool 10 and the change in the integrated mass. For example, as shown in FIG. 9, when the vibration damping range is narrowed, the vibration suppression effect in the vibration damping range is enhanced, but as shown in FIG. 10, when the vibration damping range is widened, the vibration suppression in the vibration damping range is enhanced. The effect is reduced. The worker should decide α in consideration of these properties. For example, it was experimentally found that when the natural frequency ω _n = 0.5 of the machine tool 10, the vibration may vary in the range of 0.4 to 0.6 around 0.5 depending on the conditions. If so, α = 0.8 can be calculated by setting ω _zero = 0.4 and 0.6, and K can be obtained from this. If K and _Tn are known, a and b of the convex acceleration / deceleration filter can be determined, so that a convex acceleration / deceleration filter having a vibration damping range of 0.4 to 0.6 can be easily designed.

このとき、数１２で導出される解は、以下の数１３における（Ａ）～（Ｇ）の７つの解がある。

これら（Ａ）～（Ｇ）のうち本実施形態で求める解は（Ｅ）である。（Ｅ）は、制振範囲内で周波数応答が最大値となる周波数ωに相当する。（Ｅ）に基づき、ω（Ｈｚ）は、以下の数１４のように表すことができる。

このときの周波数応答の振幅は、以下の数１５で算出できる。

With reference to FIG. 9, a method for confirming the vibration suppression effect of the convex acceleration / deceleration filter will be described. As described above, in the frequency response when processed by the convex acceleration / deceleration filter, the vibration suppression effect within the vibration damping range changes according to the width of the vibration damping range determined by the operator. Therefore, it is necessary to determine α so that the maximum value of the frequency response within the vibration damping range is within the allowable range based on the vibration characteristics of the machine tool 10. For example, in the frequency characteristics shown in FIG. 9, the following equation 12 is set in order to obtain the frequency ω at which the frequency response within the vibration damping range becomes the maximum value. Equation 12 is a mathematical formula for obtaining ω that becomes 0 by differentiating A (ω), which is a gain function of the frequency response, with ω.

At this time, the solution derived by the equation 12 has the following seven solutions (A) to (G) in the equation 13.

Of these (A) to (G), the solution obtained in this embodiment is (E). (E) corresponds to the frequency ω at which the frequency response becomes the maximum value within the vibration damping range. Based on (E), ω (Hz) can be expressed as the following number 14.

The amplitude of the frequency response at this time can be calculated by the following equation 15.

Therefore, in the present embodiment, the maximum value _A of the frequency response within the vibration damping range can be obtained by substituting the parameters K and Tn into the equation 15. Taking advantage of this, the numerical control device 20 receives, for example, the parameters K and _Tn input by the operator and substitutes them into the above equations 14 and 15, respectively, so that the frequency response within the vibration suppression range can be obtained. It is preferable to calculate the maximum value A and the frequency ω at that time, and display the calculation results on the display unit 18. The operator refers to the maximum value A of the frequency response displayed on the display unit 18, the frequency ω at that time, and the vibration characteristics obtained by, for example, hammering the target machine, and an appropriate vibration control range. Can be decided.

For example, in the frequency response of the Bode diagram shown in FIG. 9, Tn ₌ 2 (sec) and K = 0.809. By substituting these T _n and K into the equation 14, it can be calculated that the frequency ω = 0.4435 which is the maximum value of the vibration damping range. On the other hand, by substituting Tn and K for the equation 15, the maximum value A of the vibration damping range A = _0.0247 can be calculated.

The speed pattern and the acceleration pattern when the speed command is processed by the convex acceleration / deceleration filter will be described with reference to FIGS. 11 and 12. As shown in FIG. 11, the speed pattern at the time of movement of the feed axis starts moving at t0, accelerates over T1 time, and reaches the maximum speed at t1. In such an acceleration period, the inclination becomes slightly steeper at p1 after the start of movement at t0, and the inclination becomes slightly gentle at p2 before reaching the maximum speed at t1. That is, the acceleration increases in the middle part of the acceleration period, and decreases before and after that. After reaching the maximum speed at t1, it will move at the maximum speed over T2 hours. After that, deceleration starts at t2, gradually decelerates over T3 time, and stops at t3. It should be noted that T3 and T1 have the same time. Even in such a deceleration period, the inclination becomes slightly steeper at p3 after the start of deceleration at t2, and the inclination becomes slightly gentle at p4 before stopping at t3. That is, the acceleration is large even in the middle part of the deceleration period, and is small before and after that.

As shown in FIG. 12, the acceleration corresponds to the velocity pattern of FIG. In the acceleration period from t0 to t1, the maximum acceleration is between p1 and p2, but before and after that, the acceleration is lower than the maximum acceleration between t0 and p1 and between p2 and t1. .. Even in the deceleration period from t2 to t3, the maximum acceleration is between p3 and p4, but the acceleration is lower than the maximum acceleration between t2 and p3 and between p4 and t3 before and after that. .. The numerical control device 20 can effectively suppress the vibration generated in the feed shaft by controlling the feed shaft with such a speed pattern and an acceleration pattern. The maximum acceleration indicates the acceleration with the highest absolute value of acceleration. The maximum acceleration A _max is obtained by multiplying the velocity F of the input signal by b.

A filter setting process executed by the CPU 21 will be described with reference to FIG. As described above, the numerical control device 20 controls the acceleration / deceleration of the feed shaft by using the convex acceleration / deceleration filter having the above function in the acceleration / deceleration process (S5) of the main process shown in FIG. In order to design a convex acceleration / deceleration filter corresponding to the vibration characteristics of the machine tool 10, the parameters _Tn and α are required. The operator determines _Tn from the natural frequency of the machine tool 10, determines the vibration damping range, and calculates α. The operator selects a filter setting from the menu screen displayed on the display unit 18 of the operation panel 16 in order to input T _n and α. When the CPU 21 accepts the selection of the filter setting, the CPU 21 reads the filter setting program from the ROM 22 and executes this process.

The CPU 21 displays an input screen on the display unit 18 (S11). The input screen includes input fields for parameters T _n and α. The operator uses the input unit 17 to input T _n and α into each input field, respectively. The T _n and α to be input are preferably determined based on, for example, the vibration characteristics of the machine tool 10, the variation in the assumed manufacturing process of the machine tool 10, the range of the loaded mass, and the like. The CPU 21 determines whether or not the input of _Tn and α is completed (S12). For example, the operator inputs the numerical values of T _n and α in each input field, and presses the enter button. Until the press of the enter button is accepted (S12: NO), the CPU 21 returns to S12 and waits. When the press of the enter button is accepted, the CPU 21 determines that the input of T _n and α is completed (S12: YES), confirms the input T _n and α, and stores them in the RAM 23 (S13).

The CPU 21 calculates K by substituting the α stored in the RAM 23 into the above number 10 (S14). The CPU 21 calculates a and b by substituting K calculated as T _n into the above equations 3 and 4 (S15). The CPU 21 displays the calculation results of a and b on the display unit 18 (S16). The operator can determine whether or not K, a, and b are appropriate by checking the calculation result displayed on the display unit 18. If the values a and b are calculated and the values are inappropriate, the CPU 21 may display an error on the display unit 18, return to S11 again, and accept the input of the parameter again.

The CPU 21 sets the calculated a and b and the _Tn stored in the RAM 23 in the convex acceleration / deceleration filter (S17). Construction of the convex acceleration / deceleration filter is completed. The CPU 21 stores the information (for example, a, b, _Tn ) of the constructed convex acceleration / deceleration filter in the storage device 24 (S18), and ends this process. Therefore, when the acceleration / deceleration process (S5) of the main process shown in FIG. 2 is executed, the CPU 21 can process the speed command by using the convex acceleration / deceleration filter stored in the storage device 24.

Next, in order to confirm the damping effect of the convex acceleration / deceleration filter, a simulation of table movement using the convex acceleration / deceleration filter was performed.

The experimental conditions will be explained. In the experiment, a vertical machine tool 10 that can move the table was used. In this experiment, it is assumed that the machine tool 10 is known to change the natural frequency of the table in the range of 40 to 50 Hz depending on the loaded mass on the table. Therefore, the vibration damping range of the convex acceleration / deceleration filter was set to 40 to 50 Hz, and a conventional FIR filter was used as a comparative example for comparison by simulation. The details of each filter are as follows.
-Conventional filter: A normal FIR filter, using a two-stage FIR filter (moving average) of 20 ms (50 Hz) and 25 ms (40 Hz).
_-Convex acceleration / deceleration filter: Tn = 22.2 ms (about 45 Hz). Since 40 Hz is 45 × 0.888, α = 0.888. K is 0.939 from the above number 11.
The time constant of the conventional filter is 25 ms + 20 ms = 45 ms. On the other hand, the time constant of the convex acceleration / deceleration filter is T _n + 2 (T _n / 2) = 2T _n , and T _n = 22.2 ms, so that 2 × 22.2 ms = 44.4 ms. .. That is, the time constant of the conventional filter and the time constant of the convex acceleration / deceleration filter are set to be substantially the same. Therefore, the movement time of the table is almost the same regardless of which filter processes the speed command.

In the experiment, the speed commands when the table is moved along the movement path shown in FIG. 14 are processed by the above two filters, respectively, and the vibration when the table is moved by the speed commands after the processing is analyzed and compared. did. The movement path is a straight path of 10 mm in the X-axis direction. The vibration was the residual vibration of the table. Residual vibration is vibration that is stopped after moving in the X-axis direction. The machine model of the machine tool 10 is a secondary lag system with ζ = 0.01.

With reference to FIG. 15, the frequency response of the above two filters and their characteristics will be described. The upper part of the chart of FIG. 15 shows the board diagram showing the frequency response of the above two filters, and the lower part shows the change of the phase with respect to the frequency. The unit of gain in FIG. 15 is dB (decibel). The dotted line shows the conventional filter, and the solid line shows the convex acceleration / deceleration filter. In the conventional filter, the gain is small at (A) 40 Hz and (E) 50 Hz, and a peak of gain is formed between them. On the other hand, in the convex acceleration / deceleration filter, the gain is small at (A) 40 Hz, (C) 45 Hz, and (E) 50 Hz, and between (A) and (C), (C) and (E). A mountain of gain is formed between them. It can be said that the convex acceleration / deceleration filter has an excellent vibration damping effect because the gain is always smaller than that of the conventional filter in the vibration damping range (A) to (E). On the other hand, when the frequency exceeds 50 Hz, the gain of the convex acceleration / deceleration filter is larger than that of the conventional filter, so that it can be said that the vibration damping effect is inferior at the frequency exceeding 50 Hz.

Based on the above studies, in this experiment, we decided to compare the vibrations generated when the table is moved at the five frequencies within the vibration control range of (A) to (E) shown in FIG. The five frequencies are (A) 40 Hz, (B) 42.5 Hz, (C) 45 Hz, (D) 47.5 Hz, and (E) 50 Hz.

The vibration results of the table for each of the five frequencies will be described with reference to FIGS. 16 to 20. Of the three charts, the upper row is the waveform diagram of the position command, the middle row is the waveform diagram of the vibration generated in the table, and the lower row is the waveform diagram of the acceleration command. The dotted line indicates a conventional filter, and the solid line indicates a convex acceleration / deceleration filter. The waveform diagram of the table position shows the vibration generated in the table.

-Frequency = 40Hz-
As shown in FIG. 16, looking at the waveform diagram in the middle stage, vibration did not occur in either the conventional filter or the convex acceleration / deceleration filter after the table reached 10 (mm) and stopped. Therefore, at 40 Hz, no vibration was generated in the table, and it was found that the vibration was suppressed to almost zero.

-Frequency = 42.5Hz-
As shown in FIG. 17, looking at the waveform diagram in the middle stage, it can be seen that the conventional filter cannot suppress the vibration because the table vibrates greatly after reaching 10 (mm) and stopping. Do you get it. On the other hand, in the convex acceleration / deceleration filter, after the table reaches 10 (mm) and stops, it vibrates slightly, but its amplitude is much smaller than that of the conventional filter. Therefore, at 42.5 Hz, it was found that the vibration of the table was suppressed when treated with the convex acceleration / deceleration filter as compared with the conventional filter.

-Frequency = 45Hz-
As shown in FIG. 18, looking at the waveform diagram in the middle stage, in the conventional filter, after the table reaches 10 (mm) and stops, it vibrates more than at 42.5 Hz, so it vibrates. It turned out that it could not be suppressed. On the other hand, in the convex acceleration / deceleration filter, vibration did not occur after the table reached 10 (mm) and stopped. Since the convex acceleration / deceleration filter sets the center frequency of the vibration damping range to 45 Hz, it was found that no vibration was generated in the table and the vibration was suppressed to almost zero.

-Frequency = 47.5Hz-
As shown in FIG. 19, looking at the waveform diagram in the middle stage, it can be seen that the conventional filter cannot suppress the vibration because the table vibrates greatly after reaching 10 (mm) and stopping. Do you get it. On the other hand, in the convex acceleration / deceleration filter, after the table reaches 10 (mm) and stops, it vibrates slightly, but its amplitude is much smaller than that of the conventional filter. Therefore, it was found that even at 47.5 Hz, the vibration of the table was suppressed when the convex acceleration / deceleration filter was used as compared with the conventional filter.

-Frequency = 50Hz-
As shown in FIG. 20, looking at the waveform diagram in the middle stage, vibration did not occur in either the conventional filter or the convex acceleration / deceleration filter after the table reached 10 (mm) and stopped. Therefore, at 50 Hz, no vibration was generated in the table, and it was found that the vibration was suppressed to almost zero.

From the above simulation results, since the conventional filter is a moving average filter with two frequencies of 40 Hz and 50 Hz, vibration can be suppressed to almost 0 at those two frequencies, but vibration is suppressed at other frequencies. I found that I couldn't. On the other hand, the convex acceleration / deceleration filter of the present invention can suppress vibration to almost 0 at 40 Hz, 45 Hz, and 50 Hz, and can also suppress vibration at 42.5 Hz and 47.5 Hz, which are between the respective frequencies. It turned out that. Therefore, it was confirmed by simulation that the convex acceleration / deceleration filter can effectively suppress vibration in the vibration control range of 40 to 50 Hz centered at 45 Hz. Looking at the acceleration waveforms shown in the lower part of FIGS. 16 to 20, the maximum value of the acceleration command waveform after passing through the convex acceleration / deceleration filter is smaller than that of the conventional filter. This means that the conventional filter can be replaced with a convex acceleration / deceleration filter without changing the motor, drive circuit, or the like.

The relationship between the value of K and the frequency at which vibration damping is possible will be described with reference to FIGS. 21 to 24. As described above, K is a parameter for adjusting the ratio of the height a of the first stage and the height b of the second stage of the convex acceleration / deceleration filter. The vibration-damping frequency of the convex acceleration / deceleration filter changes depending on whether a positive value is set for K or a negative value is set.

The Bode diagram of FIG. 21 shows the frequency response of the convex acceleration / deceleration filter when a positive value is set for K. K was set to 0, 0.1, 0.2, and 0.3, respectively, and the frequency responses of the convex acceleration / deceleration filters corresponding to each K were compared. Focusing on the first valley part from the lowest frequency, the frequency of the valley when a positive value is set for K with respect to the waveform diagram of K = 0, the larger K becomes in the positive direction, the more It is shifting to the high frequency side. On the contrary, the portion of the third valley from the lower frequency shifts to the lower frequency side as the inverse K becomes larger. FIG. 22 is a chart of the acceleration pattern processed by the convex acceleration / deceleration filter when a positive value is set for K. The waveform of K = 0 is rectangular and has no protrusion, but when a positive value is set for K, the center of the waveform is a convex shape that protrudes upward, and the absolute value of K can be increased. The more the protruding part becomes larger.

So far, K has shown an example of a positive value, but K can be a negative value. The Bode diagram of FIG. 23 shows the frequency response of the convex acceleration / deceleration filter (concave acceleration / deceleration filter) when a negative value is set for K. K was set to 0, -0.1, -0.2, and -0.3, respectively, and the frequency responses of the acceleration / deceleration filters corresponding to each K were compared. Focusing on the first valley part from the lowest frequency, the frequency of the valley when a negative value is set for K with respect to the waveform diagram of K = 0, the larger K becomes in the negative direction, the more It is shifting to the low frequency side. On the contrary, the portion of the third valley from the lower frequency shifts to the higher frequency side as the inverse K becomes larger. FIG. 24 is a chart of the acceleration pattern processed by the convex acceleration / deceleration filter when a negative value is set for K. When a negative value is set for K, the central portion of the waveform is recessed, and the larger the absolute value of K, the smaller the recessed portion. Here, it was found that when a negative value is set for K for the frequency of the first valley, the frequency is lower than the frequency controlled by the conventional acceleration / deceleration filter having the same time constant. For example, in the above-mentioned convex acceleration / deceleration filter, since Tn = _0.0222 ms, the time constant = 0.0444 ms. In the conventional acceleration / deceleration filter based on the moving average, the frequency (vibration damping frequency) of the first valley from the lowest frequency in the frequency response is 22.5 Hz. However, as shown in FIG. 23, the frequency of the first valley from the lower frequency in the frequency response of the convex acceleration / deceleration filter when K is set to a negative value is clearly lower than 22.5 Hz. Therefore, when a negative value is set for K, vibration at a lower frequency than that of the conventional acceleration / deceleration filter can be suppressed, so that vibration at a low frequency can be suppressed without extending the time constant.

As described above, the CPU 21 of the numerical control device 20 of the present embodiment controls the acceleration / deceleration of the servomotor by processing the speed command of the servomotor that drives the machine tool 10 with the convex acceleration / deceleration filter. conduct. The convex acceleration / deceleration filter is an FIR filter that defines an impulse response to an input signal, and is a two-stage convex filter in which the impulse response becomes convexly large in the central portion of the time axis. By processing the speed command with the convex acceleration / deceleration filter, it is possible to suppress the vibration generated when the feed shaft moves, for example, within the frequency range centered on the natural frequency of the machine tool 10. The convex acceleration / deceleration filter includes a front side portion 31, a central portion 32, and a rear side portion 33.

The CPU 21 executes the filter setting process and accepts the inputs of the parameters _Tn and α from the operator. T _n and α are parameters for defining the vibration damping range centered on the natural frequency of the machine tool 10. T _n is the reciprocal of the natural frequency and is the period of the natural frequency. α is the ratio of ω _zero to ω _n . ω _n is the center frequency of the vibration damping range, and is the natural frequency in this embodiment. ω _zero is a frequency other than ω _n at which the frequency response becomes 0 within the damping range, and is two boundary values that determine the width of the damping range.

The CPU 21 obtains the parameter K based on T _n and α received from the operator. K is a parameter for adjusting the ratio of the height a of the first stage (front side portion 31 and the rear side portion 33) of the convex acceleration / deceleration filter to the height b of the second stage (central portion 32). The CPU 21 sets a and b of the convex acceleration / deceleration filter based on the obtained K. Therefore, the numerical control device 20 can suppress vibration within a range having a certain width around the natural frequency of the machine tool 10. Since the numerical control device 20 can easily optimize the range of vibration suppression of the machine by the parameters _Tn and α input by the operator, it depends on the expected variation in the manufacturing process of the machine tool 10 and the range of the loaded mass. The optimum convex acceleration / deceleration filter can be easily designed.

In the above description, the machine tool 10 is an example of the machine of the present invention. The CPU 21 that executes the process of S5 of the main process shown in FIG. 2 is an example of the acceleration / deceleration control unit of the present invention. The CPU 21 that executes the process of S12 of the filter setting process shown in FIG. 13 is an example of the reception unit of the present invention. The CPU 21 that executes the process of S14 is an example of the calculation unit of the present invention. The CPU 21 that executes the process of S17 is an example of the setting unit of the present invention. The parameters T _n and α are examples of the range information of the present invention.

Needless to say, the present invention is not limited to the above embodiment and can be modified in various ways. The CPU 21 of the above embodiment processes the speed command, which is an internal command generated by interpreting the NC program, with the convex acceleration / deceleration filter, but the above implementation even if the position command is processed with the convex acceleration / deceleration filter. The same effect as the morphology can be obtained. The convex acceleration / deceleration filter can be applied to commands such as acceleration commands and jerk commands that perform higher-order differentiation with respect to position commands.

The CPU 21 of the above embodiment processes the speed command using the convex acceleration / deceleration filter so that the time change of the acceleration becomes convex, but it may be processed by a method other than the convex acceleration / deceleration filter. For example, the time change of the acceleration so as to have a convex shape may be directly calculated.

In the filter setting process (see FIG. 13) of the above embodiment, the CPU 21 accepts the input of the parameter α in the input unit 17 of the operation panel 16, but for example, it accepts the inputs of ω _n and ω _zero and uses them. You may try to calculate α.

The machine tool 10 of the above embodiment is a vertical machine tool whose spindle extends in the Z-axis direction, but may be a horizontal machine tool whose spindle extends in the horizontal direction.

In the convex acceleration / deceleration filter of the above embodiment, the center frequency ω _n of the vibration damping range is set to the natural frequency of the machine, but other frequencies may be set.

The CPU 21 of the above embodiment processes the speed command with one convex acceleration / deceleration filter in the acceleration / deceleration process (S5) of the main process. For example, a plurality of convex acceleration / deceleration filters having different vibration damping ranges. May be processed with. In this case, vibration can be suppressed in a wider frequency range as compared with the case of processing with one convex acceleration / deceleration filter.

In the filter setting process (see FIG. 13) of the above embodiment, the CPU 21 accepts the input of the parameter α in the input unit 17 of the operation panel 16, but for example, using a separate PC or the like, for example, the parameter α, Inputs of ω _n and ω _zero may be accepted, parameters representing the convex acceleration / deceleration filter, for example, a, b, and Tn may be calculated and directly input from the input unit 17.

In this embodiment, instead of the CPU 21, a microcomputer, an ASIC (Application Specific Integrated Circuits), an FPGA (Field Programmable Gate Array), or the like may be used as a processor. The movement control process may be distributed by a plurality of processors. The ROM 22 and the storage device 24 for storing the program may be composed of other non-temporary storage media such as an HDD and / or a storage device. The non-temporary storage medium may be any storage medium capable of retaining information regardless of the period for storing the information. The non-temporary storage medium may not include a temporary storage medium (eg, a signal to be transmitted). Various programs such as an ascending stroke control program, a descending stroke control program, an NC program, and parameters representing a convex acceleration / deceleration filter are downloaded (that is, transmitted as a transmission signal) from, for example, a server connected to a network (not shown). ), May be stored in a storage device such as a flash memory. In this case, the program may be stored in a non-temporary storage medium such as an HDD provided in the server.

10 Machine tool 20 Numerical control device 11 Z-axis motor 13 X-axis motor 14 Y-axis motor 16 Operation panel 21 CPU

Claims (6)

Acceleration / deceleration control of the servomotor is performed by calculating and applying the change in acceleration or speed with respect to the time axis based on a given acceleration / deceleration pattern to the speed command or position command of the servomotor that drives the machine. In a numerical control device equipped with a deceleration control unit,
The acceleration / deceleration pattern is a two-stage convex acceleration / deceleration pattern in which the acceleration or speed increases convexly in the central portion of the time axis , and when applied to the speed command, the acceleration / deceleration pattern is relative to the time axis. It indicates the change in acceleration, and when applied to the position command, it indicates the change in speed with respect to the time axis.
The acceleration / deceleration control unit
A reception unit that accepts input of range information indicating the range of frequencies that suppress the vibration of the machine, and
Based on the range information received by the reception unit, the ratio of the magnitude of the acceleration or velocity of the first stage in the convex acceleration / deceleration pattern to the magnitude of the acceleration or velocity of the second stage larger than the first stage is determined. The calculation unit to calculate and
A numerical control device including a setting unit for setting the size of each of the first stage and the second stage of the convex acceleration / deceleration pattern based on the ratio calculated by the calculation unit. When the period of the central portion of the convex acceleration / deceleration pattern is _Tn , which is the reciprocal of the median of the frequency range for damping the machine.
The numerical value according to claim 1, wherein the period of each of the front side portion which is the front side of the central portion and the rear side portion which is the rear side of the convex acceleration / deceleration pattern is T _n / 2. Control device. When the magnitude of the acceleration or velocity in the first stage of the convex acceleration / deceleration pattern is a and the magnitude of the acceleration or velocity in the second stage is b.
The numerical control device according to claim 1 or 2, wherein a ≠ b. The acceleration / deceleration control unit has a filter corresponding to the convex acceleration / deceleration pattern, and the filter performs the acceleration / deceleration control of the servomotor by processing the speed command or the position command. The numerical control device according to any one of claims 1 to 3, wherein the numerical control device is characterized. To the filter, a rectangular first filter having the acceleration or velocity magnitude a in the first stage and a rectangular second filter having the acceleration or velocity magnitude b in the second stage are added. Assuming a convex filter that is also expressed together,
The period of the central portion of the convex acceleration / deceleration pattern is transformed by Laplace transforming the ratio of T _n , a and b, which are the reciprocals of the median of the frequency range to be damped, to K, and the area of the convex filter. When the equation consisting of T _n and K is F (s),

And
When the ratio of the frequency at which the vibration becomes 0 in the frequency range of the vibration damping frequency when the speed command or the position command is processed by the filter and the center frequency of the range is α.
K = -COS (απ)
The numerical control device according to claim 4, wherein the numerical control device is characterized by the above. Acceleration / deceleration control of the servomotor is performed by processing the magnitude of acceleration or speed with respect to the time axis based on a given acceleration / deceleration pattern in response to the speed command or position command of the servomotor that drives the machine. In the control method of the numerical control device provided with the deceleration control step,
The acceleration / deceleration pattern is a two-stage convex acceleration / deceleration pattern in which the acceleration or speed increases convexly in the central portion of the time axis , and when applied to the speed command, the acceleration / deceleration pattern is relative to the time axis. It indicates the change in acceleration, and when applied to the position command, it indicates the change in speed with respect to the time axis.
The acceleration / deceleration control step is
A reception step that accepts input of range information indicating the range of frequencies that suppress the vibration of the machine centered on the natural frequency of the machine.
Based on the range information received in the reception step, the ratio of the magnitude of the acceleration or velocity of the first stage in the convex acceleration / deceleration pattern to the magnitude of the acceleration or velocity of the second stage larger than the first stage is determined. Calculation steps to calculate and
A control method comprising: a setting step for setting the size of each of the first stage and the second stage of the convex acceleration / deceleration pattern based on the ratio calculated in the calculation step.

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