JPH074649Y2 - Numerical control device - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention is, for example, in a machine tool or the like, a numerical value for commanding the movement amount of a work or the like by an angle and setting the work or the like at a predetermined angle. Regarding the control device.

(Prior Art) In recent years, with the automation and labor saving of production lines due to the demands of the times, NC machine tools are introduced even in the fields of assembling precision parts and production processing, which were conventionally performed by skilled workers. In addition, work in these fields has become relatively easy to perform without human intervention.

In this NC machine tool, since high-precision positioning of the work is an important element for performing high-precision machining, the control device for performing the positioning is configured as shown in FIG. High precision machining is possible.

As shown in the figure, the selector 10 for selecting the required movement angle θ of the workpiece 3 and the rotation direction thereof is stored in the rotation angle storage unit 16 storing a plurality of required movement angle data of the workpiece 3 by the selector 10. A rotation angle extraction unit 17 for extracting the selected predetermined required movement angle data is connected to the rotation angle extraction unit 17, and the required movement angle θ extracted from the rotation angle storage unit 16 is determined according to the angle. A pulse converter 18 for converting the command pulse D into the command pulse D is connected.

On the other hand, the work 6 to be positioned is connected to the motor 6 via a drive mechanism (not shown), and
A pulse generator 9 for generating B pulses (for example, 1000 or 2000 pulses) per one rotation is provided.

This pulse generator 9 and the above-mentioned pulse converter 18
Is connected to a deviation register 19 which calculates a deviation pulse Pc which is the difference between the command pulse D output from the pulse converter 18 and the feedback pulse Pk output from the pulse generator 9.

The deviation register 19 is connected with a D / A conversion section 20 for converting the deviation pulse Pc calculated in the deviation register 19 into a voltage value. The D / A conversion section 20 has a servo for operating the motor 6. Amplifier 15 is connected.

The operation of the conventional numerical control device thus configured is
Description will be made based on the operation flowchart shown in the figure.

First, the required movement angle θ of the work 3 and its rotation direction are selected by the selector 10. When this selection is made, the rotation angle extraction unit 17 reads out the data selected from the required movement angle data stored in the rotation angle storage unit 16 and sets it as the command value A (step 1). Next, the pulse converter 18
Performs a calculation for converting into a command pulse D corresponding to the command value A. This command pulse D is sent to the deviation register 19 (step 2).

Then, the deviation register 19 receives the feedback pulses Pk sequentially sent from the pulse generator 9 (step 3), subtracts the command pulse D from the feedback pulse Pk,
The deviation pulse Pc is calculated (step 4). Deviation register
In step 19, if the deviation pulse Pc is not zero as a result of the calculation in step 4, the process of step 6 is performed, and if the deviation pulse Pc is zero, the process of step 9 is performed (step 5).

The D / A converter 20 converts the deviation pulse Pc into a voltage value V _C corresponding to the deviation pulse Pc (step 6), and the servo amplifier 15 amplifies this voltage value V _C and applies it to the motor 6. (Step 7). Then, the motor 6 rotates at a speed according to the applied voltage to rotate the work 3. At this time, the pulse generator 9 generates a feedback pulse Pk corresponding to the rotation angle of the motor 6, and this feedback pulse Pk is fed back to the deviation register 19 (step 8).

On the other hand, when the deviation pulse Pc calculated in step 4 is judged to be zero in the deviation register 19, the output voltage of the servo amplifier 15 becomes zero and the motor 6 stops (step 9).

In this way, the work 3 is set to the angle set by the selector 10.

(Problems to be solved by the invention) In the conventional numerical control device as described above, however, the required movement angle θ of the work 3 set by the selector 10 and the angle at which the work 3 is actually set. There is a problem that an error ε is generated between it and θ ′.

That is, conventionally, the pulse generator 9 having a resolution of about 500 to 2,000 pulses generated per one rotation of the motor 6 is used for reasons such as low cost and easy availability. However, for example, when the pulse generator 9 that generates 1000 pulses per one rotation of the motor 6 is used, this resolution is 1000 pulses / 3
60 degrees = 2.777 pulses / degree, and when the workpiece 10 is selected to rotate by 60 degrees, the pulse conversion unit 18
Must output 2.777 ... × 60 = 166.666 ... pulses to the deviation register 19, but since the fractional pulse below the decimal point is not output to the deviation register 19, 166 pulses are sent to the deviation register 19. As a result, the truncated fractional pulse causes an error in the actual set angle of the work 3.

This error becomes a cumulatively large error when the movement command to the work 3 is repeated, and there is a possibility that the precision machining of the work 3 cannot be performed due to this error. In order to eliminate such problems, for example, 360 revolutions per revolution of the motor 6
If a pulse generator that generates a pulse of a predetermined integer multiple of ° is used, it is possible to prevent the generation of a fractional pulse at the time of conversion from an angle to a pulse in the pulse conversion unit 18, but such a pulse generator is a mass-produced product. Since it is not available, it will be a special order, and another problem will occur that the acquisition cost will be high (2 to 3 times higher than usual).

The present invention has been made in view of the above problems, and an object of the present invention is to provide a numerical control device capable of highly accurately setting a workpiece at a predetermined angle according to a command value of the existing device. To do.

(Means for Solving the Problems) The present invention for achieving the above-mentioned object includes a setting means for setting a necessary movement angle [θ] of a work, a driving means for driving the work, and one rotation of the driving means. A pulse generator that outputs a hit [B] pulse and a pulse that is output from the pulse generator according to the rotation amount of the drive unit are multiplied by a value [C] obtained by dividing the common multiple of B and 360 by B. A multiplying means for outputting, and a command pulse [D] corresponding to the required movement angle [θ] of the work set by the setting means,
The conversion means that outputs by calculating B.C..theta. / 360 and the command pulse [D] output from the conversion means are successively subtracted from the pulse [Pk] output from the multiplication means to obtain a deviation pulse [ Pc] is calculated by the deviation pulse calculating means, and the control means controls the operation of the driving means according to the deviation pulse [Pc] calculated by the deviation pulse calculating means.

(Operation) The operation of the present invention will be described with reference to FIG. First, the required movement angle θ set by the setting means 23 is converted by the converting means.
Calculation of B.C..theta. / 360 is performed by 18 and converted into a predetermined designated pulse D. Then, the command pulse D is output to the deviation pulse calculating means 19.

On the other hand, the feedback pulse output from the pulse generating means 9
Pk is multiplied by C in the multiplication means 21 and output to the deviation pulse calculation means 19.

The deviation pulse calculation means 19 calculates the difference between the command pulse D converted by the conversion means 18 and the feedback pulse Pk ′ sequentially output from the multiplication means 21, calculates the deviation pulse Pc, and controls this deviation pulse Pc. Output to the means 24. When the deviation pulse Pc is calculated, the feedback pulse Pk 'sequentially output from the multiplying means 21 and the command pulse D converted by the converting means 18 are matched with each other.
The count value of Pc is always an integer pulse and no fractional pulse occurs.

Therefore, the control means 24 positions the work 3 by controlling the rotation angle, the rotation direction and the rotation speed of the drive means 6 according to the count value of the deviation pulse which is an integer pulse not including the fraction pulse. It is possible to prevent an error between the commanded position and the actually set position, which occurs when the positioning of No. 3 is performed.

(Embodiment) Next, an embodiment according to the present invention will be described in detail with reference to the drawings.

FIG. 2 shows a schematic configuration diagram of a numerical control device that commands the movement distance of a work by an angle to control the positioning of the work.

As shown in the figure, a disk-shaped table 2 is rotatably provided on the housing 1, and a work 3 is fixed on the table 2 so that the work 3 rotates together with the table 2. Has become. A table support shaft 4 is attached to the center of the table 2 perpendicularly to the table 2,
A worm gear 5 is fixed to the table support shaft 4. The worm gear 5 meshes with the worm 8 provided on the drive shaft 7 of the motor 6, and transmits the rotational force of the motor 6 to the table 2. The motor 6 has
A pulse generator 9 is installed as a pulse generating means for generating a pulse according to the rotation angle of the drive shaft 7. A casing 1 of an apparatus according to the present invention, which is composed of the above-mentioned members
Is actually X which performs positioning in two orthogonal directions.
-Y is fixed on the table so that the work 3 can be positioned in the three axial directions of the two axial directions of X and Y and the rotational axis direction of the table 2. The motor 6 is connected to a control unit as shown in the figure, and the control unit is configured as follows.

The selector 10 as a setting means for selecting the required movement angle θ of the work 3 is connected to the input / output interface 11. A CPU 12 is connected to the input / output interface 11, and a ROM 13 for storing programs and the like and a RAM 14 for storing data and the like are connected to the CPU 12. Further, the input / output interface 11 is connected with a servo amplifier 15 that amplifies the voltage input via the input / output interface 11, and
The servo amplifier 15 is connected to a motor 6 as a driving means. A pulse generator 9 which is built in the motor 6 and generates a pulse according to the rotation angle of the motor 6 is also connected to the input / output interface 11, and the rotation angle of the motor 6 is fed back to the CPU 12.

Next, FIG. 3 shows a block diagram around the control unit described above.

As shown in the figure, the selector 10 for selecting the required movement angle of the work 3 and the rotation direction thereof includes a rotation angle storage unit 16 storing a plurality of required movement angle data of the work 3,
A rotation angle extraction unit 17 for extracting the predetermined required movement angle data selected by the selector 10 is connected, and the rotation angle extraction unit 17 stores the required movement angle θ extracted from the rotation angle storage unit 16, A pulse converter 18 is connected as a converter for converting the command pulse D according to the angle. The selector 10, the rotation angle storage unit 16, and the rotation angle extraction unit 17 constitute setting means 23.

On the other hand, the work 6 to be positioned is connected to the motor 6 via a drive mechanism (not shown), and
A pulse generator 9 for generating B pulses (for example, 1000 or 2000 pulses) per one rotation is provided.

The pulse generator 9 is connected with a multiplication unit 21 as a multiplication unit for multiplying the feedback pulse Pk output from the pulse generator 9 by a predetermined number and outputting the feedback pulse Pk. The multiplication unit 21 and the pulse conversion unit 18 are connected.
Is connected to a deviation register 19 as deviation pulse calculating means.

Further, the deviation register 19 is connected to a frequency divider 22 that divides the deviation pulse Pc calculated here into a predetermined magnification,
The frequency divider 22 includes a deviation pulse P after frequency division by the frequency divider 22.
A D / A converter 20 for converting k ′ into a voltage value is connected, and
The servo amplifier 15 is connected to the D / A converter 20. The frequency dividing section 22, the D / A converting section 20, and the servo amplifier 15 constitute the control means 24.

The operation of the work numerical control apparatus configured as described above is described in the fourth section.
A description will be given based on the operation flowchart shown in the figure.

First, the selector 10 selects command values for the required movement angle θ and the rotation direction of the work 3. The rotation angle extraction unit 17 reads the command value from the rotation angle storage unit 16 and sets it as the command value A (step 10). The pulse converter 18 performs an operation of converting the command value A into a command pulse number D corresponding to the command value A (step 1
1). Here, the calculation for converting the command value A into the command pulse D will be described. First, the minimum unit of the angle that can be selected by the selector 10 is a degrees, and the number of pulses generated by the pulse generator 9 per one rotation of the table 2 is B pulses. Next, assuming that the number of divisions per pulse in Table 2 is N, N is calculated by the following equation.

N = 360 / a Furthermore, the pulse generator 9 per one rotation of the table 2
Is calculated and the least common multiple of the number of pulses B generated by and the number N of divisions of the table 2 is calculated, and the calculation result is set to E. And
When the required movement angle selected by the selector 10 is θ degrees and the command pulse is D, the relationship between the two is expressed by the following equation.

D = θ · E / N The command pulse D calculated in this manner is stored in a predetermined address of the RAM 14. Further, the feedback pulse Pk 'output via the multiplier 21 is also stored in a predetermined address of the RAM 14 (step 12). The deviation register 19 is set in steps 11 and 12.
At step S13, the command pulse D and the feedback pulse Pk 'stored in the RAM 14 at a predetermined address are read out, and the deviation pulse Pc is calculated (step 13). As a result of the calculation in step 13, the deviation register 19 proceeds to step 20 when the deviation pulse Pc is determined to be zero, and stops the motor, while the deviation register Pc is determined to be not zero, the step Proceed to step 15 (step 14). Next, the frequency division
In step 22, the deviation pulse Pc is divided by a predetermined magnification (step 1
5), the D / A converter 20 performs an operation for converting the voltage value V _C corresponding to the pulse Pc ′ after the frequency division (step 16). The voltage value V _C calculated in step 16 is the servo amplifier 15
Is amplified to a voltage value V _D (step 17). When the voltage value V _D is applied to the motor 6, the motor 6 starts driving at a speed according to the applied voltage to rotate the table 2,
The work 3 is driven based on the commanded required movement angle θ and the rotation direction. On the other hand, the pulse generator 9 generates the feedback pulse Pk corresponding to the rotation angle and the rotation direction of the motor 6 (step 18). The multiplication unit 21 multiplies the feedback pulse Pk to a predetermined multiplication factor (step 19), and feeds back the feedback pulse Pk ′ thus multiplied to the deviation register 19. Here, the respective predetermined multiplication or division ratios of the multiplication unit 21 and the frequency division unit 22 will be described.

First, the multiplication rate T1 of the multiplication unit 21 will be described as follows.
It is a magnification for matching the number of generated pulses with respect to the angle between the command pulse D and the feedback pulse Pk, and is determined as follows.

T1 = E / B where B is the number of pulses generated by the pulse generator 9 per one rotation of the table 2, N is the number of divisions of the table 2, and E is the least common multiple of B and N. Further, the feedback pulse Pk is calculated by the following equation when the rotation angle of the motor 6 is a ′ degree.

Pk = B · a ′ / 360 Therefore, the feedback pulse Pk ′ fed back to the deviation register 19 is calculated by the following equation.

Pk ′ = Pk · T1 = Pk · E / B On the other hand, the frequency division ratio T2 of the frequency division unit 22 is described as follows.
It is a multiplication factor for compensating for the multiplied amount in the multiplication unit 21, and is the reciprocal of T1 as in the following equation.

T2 = 1 / T1 = B / E In order to facilitate understanding, a description will be added using a specific example. For example, consider the case where the minimum unit a of the angle that can be selected by the selector 10 is 1 degree and the number of pulses B generated by the pulse generator 9 per one rotation of the table is 2000 pulses. First, the division number N of the table 2 is calculated by the following equation.

N = 360 / a = 360 Further, the least common multiple E of the pulse number B (= 2000) and the division number N (= 360) is 18,000.

If the required movement angle θ is 20 °, the designated pulse D
Is calculated by the following equation.

D = θ · E / N = 1000 That is, the pulse converter 18 changes the required movement angle 20 ° to 1000.
The pulse is converted into a command pulse D, and this 1000 pulses are output to the deviation register 19.

On the other hand, the feedback pulse Pk generated by the pulse generator 9 when the table 2 rotates 10 ° with respect to the required movement angle 20 °
Is calculated as follows.

Pk = B · a ′ / 360 = 500/9 Further, the multiplication rate T1 is calculated by the following equation.

T1 = E / B = 9 Therefore, the feedback pulse Pk ′ output to the deviation register 19
The number of pulses is 500, and the 500 pulses are output to the deviation register 19. That is, the deviation register 19 receives the command pulse D of 1000 pulses and the feedback pulse Pk 'of 500 pulses, and the deviation pulse of 500 which is the deviation pulse of D and Pk' is output from the deviation register 19. The deviation pulse of 500 pulses is divided by 1/9 in divider 22 and divided by 5
It becomes 00/9 pulse, and this 500/9 pulse is converted into a voltage value in the D / A conversion section 20, and this voltage value is further amplified in the servo amplifier 15. The servo amplifier 15 positions the work 3 while controlling the rotation angle and the rotation speed of the motor 6 according to the output voltage from the D / A conversion unit 20, while
The pulse generator 9 generates a feedback pulse Pk according to the rotation angle and the rotation direction of the motor 6, and the feedback pulse Pk
Is multiplied by the multiplication unit 21 and output to the deviation register 19, and the same operation as described above is repeated until the deviation pulse Pc becomes zero.

(Effect of the Invention) As described in detail above, according to the present invention, the deviation calculated by the deviation pulse calculating means by matching the command pulse D and the feedback pulse Pk ′ in the converting means and the multiplying means. The pulse Pc is always an integer pulse that does not include a fractional pulse, and the control means controls the rotation direction and rotation speed of the drive means in accordance with the deviation pulse Pc that is an integer pulse that does not include a fractional pulse to position the workpiece. Therefore, the error between the required movement angle θ and the actually set angle, which occurs when positioning the work, can be prevented at low cost, and the work can be accurately moved to the desired movement angle θ. It becomes possible to position. Further, even if the number of feedback pulses generated by the feedback pulse generating means per one rotation of the motor is changed, this change can be easily performed only by changing the predetermined conversion rate in the conversion means and the multiplication rate in the multiplication means. Can respond.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a numerical controller according to the present invention, and FIG.
FIG. 3 is a schematic configuration diagram of a numerical control device according to the present invention and a conventional example, FIG. 3 is a block diagram showing a control unit periphery of the numerical control device according to the present invention, and FIG. 4 is a numerical control device according to the present invention. FIG. 5 is a block diagram showing the periphery of the control unit of the numerical control device according to the conventional example, and FIG. 6 is an operational flowchart diagram of the numerical control device according to the conventional example. 3 ... Work, 6 ... Motor (driving means), 9 ... Pulse generator (pulse generating means), 10 ... Selector (setting means), 15 ... Servo amplifier (control means), 16 ...
... rotation angle storage section (setting means), 17 ... rotation angle extraction section (setting means), 18 ... pulse conversion section (pulse conversion means), 19
…… Deviation register (deviation pulse calculation means), 20 …… D / A
Conversion unit (control means), 21 ... Multiplication unit (multiplication means), 22 ...
… Divider (control means).

Claims (1)

[Scope of utility model registration request] 1. A setting means for setting a required movement angle [θ] of a work, a drive means for driving the work, a pulse generation means for outputting a [B] pulse per one rotation of the drive means, and the drive means. A multiplication unit for multiplying the pulse output from the pulse generation unit according to the rotation amount of No. 1 by a value [C] obtained by dividing the common multiple of B and 360 by B, and outputting the pulse of the work set by the setting unit. Command pulse [D] corresponding to the required movement angle [θ]
A conversion unit that outputs by calculating / 360, and a feedback pulse [Pk] that is output from the multiplication unit is sequentially subtracted from the command pulse [D] that is output from the conversion unit, and a deviation pulse [Pc] is calculated. And a control means for controlling the operation of the drive means in accordance with the deviation pulse [Pc] calculated by the deviation pulse calculation means.