JPH07334217A - Axial position controller - Google Patents

Abstract

PURPOSE:To provide the axial position controller which executes the position and speed control of a servo motor for driving one or more synchronous driving axes at least with one microprocessor without generating any position command error. CONSTITUTION:This device is provided with a time-counting time count part 106 for generating timer data by counting the number of times of timer signal generation within a position control cycle, plural motors positions control part 2 for performing position control processing for all the motors when the first timer data are generated within the position control cycle, and plural motors speed control part 3 for successively performing speed control processing for all the motors corresponding to the timer data after the end of position control processing based on a latest speed command value generated by the plural motors positions control part 2. Thus, the position and speed of the servo motor for driving the synchronous driving axis is executed with one microprocessor while canceling the position command error in synchronous operations.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servomotor control device, and one microprocessor for controlling the position and speed of a servomotor that drives a synchronous drive shaft such as a machine tool or a robot loader. The present invention relates to an axis position control device suitable for execution.

[0002]

2. Description of the Related Art In order to drive and control a drive target having a plurality of axes (at least one axis or more) such as a machine tool or a robot loader, position and speed control of servo motors driving these axes is performed. Need to do. Normally, one position control device was required for each servo motor to drive and control these multiple axes, but in recent years there has been a strong demand for higher performance and lower cost. Cost reduction is achieved by controlling the control system using a single position control device.
FIG. 8 shows a prior art shaft position control device with four axes
It is a conceptual functional block diagram when applied to a machine tool having a single servo motor. In FIG. 8, the axis position control device 10 is connected to a servo amplifier 31 that supplies electric power to the servo motor 41 of the first axis and a position detector 51 that detects the rotational position of the servo motor 41.
From the viewpoint of controlling the torque of the first axis, the servo motor 41 is an element that constitutes the torque control device 21 together with the servo amplifier 31 in FIG. Further, the shaft position control device 10 is connected with torque control devices 22 to 24 for second to fourth axis drive control, and position detectors 52 to 54. Further, the axis position control device 10 processes the data from the interrupt signal generator 11, the position error Pe, the position controller 12 that generates the speed command value Vr based on the position error Pe, and the data from the position detector. Current position P of servo motor
a position detection unit 13 for detecting am, i, j and a position control unit 12
A speed command value storage unit 14 for storing each shaft speed command value Vr generated by the above, and a speed control unit 15 for generating a current command value Irm based on the speed error Ve and the speed error Ve.
And the current position Pam, i, j generated by the position detection unit 13.
From the velocity Vam, i, j. In the present specification, position / speed /
Subscripts in English symbols indicating current command values and detected values
Let m, i, j have the following meanings. m: Control target axis (servo motor) identification number. (1 to 4) i: Position command cycle identification number. (Positive integer) j: Position control process identification number. (Positive integer of 0 to m-1 (= 3)) When these subscripts are omitted, it is not dependent on the axis or the temporal context is not a problem.

FIG. 9 is a flow chart showing the operation of the conventional shaft position control device, and FIG. 10 is an operation time chart of the conventional shaft position control device. The operation of the conventional technique will be described below with reference to FIGS. Figure 8
NC read and interpreted by an NC program reading unit and an NC program interpreting unit not shown in FIG.
Based on the program, a function generator (not shown) calculates movement information (target position, speed, etc.) of all axes (servo motors) to be drive-controlled and outputs the position command value for the servo motors driving each axis to the i-th position. Position command value (= Pr
m, i) at a predetermined timing as the axis position control device 10
Transfer to. Inside the axis position control device 10, an interrupt signal INT for starting the position control process is generated by the interrupt signal generator 11 in synchronization with this transfer timing.
i-th position command value Prm, i Interrupt signal INT immediately after transfer
When occurs, the position control unit 12 sets j = 0 and starts the position control processing PC1 for the first axis. First, the servo motor identification number m is obtained from j (step S1 in FIG. 9). j
Since = 0, m = 1. Next, i-th position command value P
Pr1, i is read from rm, i and is set as the position command value Pr (step S2 in FIG. 9). Next, Pa1, i, 0 is selected from the position detection values Pam, I, 0 detected and generated by the position detection unit 17 for each position control cycle and set as the position detection value Pa (FIG. 9).
Step S3). In the position control unit 12, the difference between the position command value Pr and the position detection value Pa is calculated as a position error and multiplied by a predetermined gain to generate the speed command value Vr (step S4 in FIG. 9). This speed command value calculation process is performed by the interrupt signal IN
Execute only once for each T occurrence. Since j = 0 now, Vr becomes Vr1, i, 0, and this value is stored in the storage position for the first axis of the speed command value storage unit 14 (step S5 in FIG. 9). After the end of storage, the position control unit 12 activates the speed control unit 15, and ends the position control process at j = 0. The speed control processing unit 12 performs speed control processing for all servo motors for each generation of the interrupt signal INT. The speed detection value Va required for the speed control process is constantly generated by the speed detection unit 16 by a known method using two position detection values Pa obtained in a predetermined cycle, for example. The speed control unit 15 specifies the first control target (step S6 in FIG. 9) and reads the speed command value Vr1, i, 0 of the first axis from the speed command value storage unit 14 (step S6 in FIG. 9).
7). Next, the speed detection value Va1, i, 0 of the first axis is read (step S8 in FIG. 9). Next, the speed command value Vr1, i, 0
And the speed detection value Va1, i, 0 are calculated to calculate a speed error Ve, and a torque command value Tr is generated based on the speed error Ve by a known method such as proportional-integral operation feedback control. Further, the current command value Ir1 is calculated from the torque command value Tr (step S9 in FIG. 9).
This current command value is transferred to the first-axis servo amplifier 31 via the servo amplifier IF (not shown) (step S10 in FIG. 9). The steps S7 to S10 are the first
This is the speed control processing SC1 for the axis. Based on the current command value Ir1, the first-axis servo amplifier 31 finally generates a phase voltage to be applied to the servo motor 31 by a known technique. By applying this voltage, the servo motor 3
A drive torque is generated at 1, and the drive load is drive-controlled at a desired position and speed. The speed control unit 15 updates the servo motor identification subscript k after the transfer of the current command value, and checks whether or not the current command value generation / transfer up to the fourth axis is completed (steps S11 and S12 in FIG. 9). If not completed, steps S7 to S12 are repeated, and if completed, the interrupt processing is terminated and the next interrupt signal I
Wait for NT to occur. In this case, since k = 2 at the stage of the determination process in step S12, the process returns to step S7 and the second
The axis speed control process SC2 is performed. If j = 0, the second
Since the speed command values (Vr2, i, 0 to Vr4, i, 0) for the four axes are not generated, the speed command value read in step S7 is a division of j = 1 of the previous position command cycle (i-1th). The speed command value Vr2, i-1,1 calculated in the plug-in process is used. Thereafter, the current command value Ir2 for the second axis is calculated and transferred in the same manner as the speed control processing SC1 for the first axis. Similarly, the current commands Ir3 and Ir4 for the third and fourth axes are similarly performed for the speed control processes SC3 and SC4 of the third and fourth axes.
At, the speed command values Vr3, i-1,2 and Vr4, i-1,3 are calculated and transferred to each axis servo amplifier. When the position control process PC1 for the first axis and the speed control processes SC1 to SC4 for the first to fourth axes are completed in the above procedure, j
= 0, all interrupt processing is completed, and the next interrupt signal IN
Wait for the occurrence of T. When the next interrupt signal INT is generated, j =
The interrupt processing of 1 is started, and the position control processing PC2 for the second axis and the speed control processing for the first to fourth axes based on the position command value Pr2, i are performed in the same procedure as the interrupt processing of j = 0. SC1 to SC4 are executed. Thereafter, similarly, j = 2
In the interrupt processing of the third command based on the position command value Pr3, i
The position control process PC3 for the axis and the speed control processes SC1 to SC4 for the first to fourth axes are the first position control process PC3 and the first position control process PC3 for the fourth axis based on the position command value Pr4, i in the interrupt process of j = 3. ~ Speed control process S for the fourth axis
C1 to SC4 are executed. When the interrupt processing of j = 0 to 3 is completed, j is reset to 0, and the next position command value Prm,
Prepare for i + 1 transfer.

[0004]

The control operation of the shaft position control device 10 according to the prior art is executed as described above.
A time chart of this is shown in FIG. 10, in which Tpc represents a position control cycle and Tpr represents a position command cycle. As described above, in the prior art, the speed command value Vr newly calculated for each interrupt process is only for one axis, so that, for example, in the interrupt process of j = 2 in the i-th position command cycle, it is new. Vr3, i, 2 is calculated by the PC 3 as the speed command value of 1., and the following data is used as the speed command value and the speed detection value data in each axis speed control process SC1 to SC4. SC1 ... Vr1, i, 0 and Va1, i, 2 SC2 ... Vr2, i, 1 and Va2, i, 2 SC3 ... Vr3, i, 2 and Va3, i, 2 SC4 ... Vr4 , i-1,3 and Va4, i, 2 The latest position command value (= P
In the speed control process executed when the speed command value based on rm, i) is not calculated, the speed command value calculated based on the previous position command value as the speed command value for obtaining the speed error ( In the above example, Vr4, i-1,3) is adopted. Therefore, although the i-th position command value Pr4, i has already been transferred to the axis position control device 10 at the first time point, this command value is not reflected. The i-th position command value Prm, i is reflected in the speed control processing of each axis by SC1 when j = 0 on the first axis, SC2 when j = 1 on the second axis and j on the third axis. SC3 at = 2, 4th
The axis is the time point when SC4 at j = 3 is executed. This is because even if the function generating unit calculates a synchronous operation position command value to perform synchronous operation of each axis and transfers it to the axis position control device 10, it is based on this synchronous operation position command value inside the axis position control device 10. This means that there is a problem that a large synchronization error occurs at the command value level due to a time difference due to the fact that each axis speed control process is not performed within the same position control cycle. This synchronization error will be specifically described below. Now, it is assumed that movement commands of the same distance are given to both the first axis and the fourth axis as an NC program while all axes are stopped. The first axis position is the vertical axis, and the fourth axis is
If the axis position is taken as the horizontal axis, a 45-degree straight line connecting the movement start point (= Ps) and the end point (= Pd) as drawn by the dashed arrow in the first quadrant of the graph shown in FIG. 11 is an ideal command. It becomes a locus. Here, the acceleration / deceleration unit amount for the first and fourth axes (the slope of the speed curve during acceleration / deceleration), servo amplifier /
If the servo motor ratings are the same, the speed command curves for these two axes will have the same shape. Now, the speed (command) curves for the first axis and the fourth axis calculated by the speed controller 15 based on the synchronous operation position command have the same magnitude as shown in the second and fourth quadrants of FIG. If it becomes a trapezoid, because of the time difference, the speed command curve based on the synchronous operation position command value rises
In the 1st axis, IN of j = 0 in the i-th position command cycle
Immediately after the execution of SC1 during the T interrupt processing, and immediately after execution of SC4 during the INT interrupt processing of j = 3 in the i-th position command cycle in the 4th axis. Therefore,
The time difference between them is 3.5 of the actual position control period Tpc.
It doubles. INT of j = 3 in the i-th position command cycle
The speed command value is generated only for the first axis until immediately before the execution of SC4 during the interrupt processing, and the speed command value = 0 (stopped state) continues for the fourth axis. Therefore, considering that the time integrated value of the speed curve becomes the position during this period, the actual position command locus is separated from the ideal position command locus, resulting in a large synchronous operation position command error, that is, the position command in FIG. An error ERp occurs. Figure 11
In acceleration / deceleration unit amount = 1 m / S * S, position command cycle T
If pr = 10 ms and the position control cycle Tpc = 2.5 ms, the position command error ERp in FIG. 11 is about 30 μm, and the recent contour processing accuracy requirement is from submicron to several μm.
Considering that, it is a big problem in practical use.
The present invention has been made to solve the above problems, and an object of the present invention is to control the position and speed of a servo motor that drives a synchronous drive shaft without causing the problem of position command error in synchronous operation. An object of the present invention is to provide an axis position control device that is executed by a single microprocessor.

[0005]

In order to achieve the above object, the invention according to claim 1 executes position control and speed control of at least one or more motors based on an input position command value. In the axis position control device, a clock signal generating unit that generates a clock signal at every constant cycle, and a clock frequency counting unit that counts the clock signal generation frequency within the position control cycle and generates clock data at regular intervals. , A plural position control for performing a position control process for calculating a speed command value based on the corresponding position command values for all the motors when the time count counting unit first generates the time measurement data in a predetermined position control cycle. Unit and all the units within the position control cycle in accordance with the time count data generated by the time count counting unit based on the speed command value generated by the multiple unit position control unit. And having between multiple speed controller for sequentially controlling the speed processing with respect to motor. Further, according to a second aspect of the present invention, in the axis position control device that executes position control and speed control of at least one motor based on the input position command value, a plurality of interrupt signals having different cycles are generated. An interrupt signal generation unit, a motor number storage unit for storing data on the number of motors to be controlled, and position control execution for executing position control from the interrupt signals according to the stored contents of the motor number storage unit. An interrupt signal selection unit that selects and outputs an interrupt signal and a speed control execution interrupt signal that executes speed control, and a predetermined position when a position control execution interrupt signal is generated. Multiple units that perform position control processing for all motors within the control cycle, and multiple units that sequentially perform speed control processing for all motors within the position control cycle when a speed control execution interrupt signal is generated. speed When the number of the motors is 1, the interrupt signal selection unit lowers the priority of the position control execution interrupt signal below the priority of the speed control execution interrupt signal. When the number of motors is plural, the priority of the position control execution interrupt signal is set higher than that of the speed control execution interrupt signal.

[0006]

Therefore, according to the present invention, within the same position control cycle, the plurality of units position control section calculates the speed command value for all the motors based on the latest position command value in the position control processing, and the plurality of units position control units are calculated. The speed control unit sequentially performs speed control processing for all the motors based on the speed command value. Therefore, since the speed control processing of each axis is performed based on the data calculated within the same position control cycle, it is possible to avoid a large synchronous operation position command error that occurs at the command value level due to the time difference of the processing time. When the number of motors to be controlled is 1, the interrupt signal selection unit lowers the priority of the position control execution interrupt signal below the priority of the speed control execution interrupt signal. If there are a plurality of positions, the priority of the position control execution interrupt signal is set higher than the priority of the speed control execution interrupt signal, so that the position control processing is not interrupted by the speed control processing. Since the speed control processing of each axis is performed based on the data calculated in the same position control cycle, it is possible to avoid a large synchronous operation position command error that occurs at the command value level due to the time difference of the processing time.
At the same time, the axis position control device can be used as a one-axis position control device by changing the priority.

[0007]

FIG. 1 is a conceptual functional block diagram when the shaft position control device of the first embodiment according to the present invention is applied to a machine tool having four axes, that is, four servo motors. In the first embodiment, for the sake of convenience, the axis control and the motor control are regarded as the same. 2 is a hardware configuration diagram showing the shaft position control device of the first embodiment of the present invention, and FIG. 3 is a flow chart showing the operation of the shaft position control device of the first embodiment of the present invention. FIG. 4 is an operation time chart of the shaft position control device according to the first embodiment of the present invention. In FIGS. 1, 3 and 4, the functions and processing contents of the components indicated by the same numbers as those of FIGS. 8, 9 and 10 showing the conventional technique are the same as those of the conventional technique, and therefore the description thereof is omitted. However, only the essential parts of the present invention will be described below. 1, in addition to the components common to the shaft position control device according to the prior art, the shaft position control device 1 also includes a time signal generated by the time signal generation unit at regular intervals,
That is, the hardware clock signal C having a fixed cycle
LK is timed for the length of the speed control cycle, and the number of times of time counting within the position control cycle is counted to measure time data CNT.
And a plurality of units position control unit 2 for performing position control processing of all servo motors when the time count data is CNT = 0, and a plurality of units generated by the plurality of unit position control unit 2. A plurality of units speed control unit 3 that sequentially performs speed control processing of all the motors on the basis of the speed command value according to the time count data. Next, the operation of the first embodiment will be described with reference to FIGS. The hardware configuration of the axis position control device 1 is as shown in FIG. 2, and includes a system bus and a system bus IF 105, which is a transfer path of a position command value, a microprocessor 101, a read only memory (ROM) 102, a random access memory. (RAM) 103, time count counter 106, position detector IF 120, servo amplifier IF
It is composed of 130. The time count counting unit 106
Is a time counter for identifying control processing, and is a hardware clock signal CL in the axis position control device 1.
When K is input to the time count counting unit 106 and time is counted for the time length of the speed control cycle, the count data initially set to 0 is incremented by 1. This count data is used as time measurement data CNT by the microprocessor 10
Forwarded to 1. The range of the value of the time measurement data CNT is 0 to 4. This range is determined by the sum of the number of times of position control processing and speed control processing to be executed in one position control cycle in the axis position control device 1. In the present embodiment, the number of times is four for the position control processing once and the speed control processing once for each axis.
The value range of is set to 0-4. The speed control cycle in the axis position control device 1 is determined so as not to be shorter than the longer of the speed control processing time for one motor and the position control processing time for all motors. The microprocessor 101 sequentially executes processing programs stored in the ROM 102 in advance by using the time measurement data CNT to execute various kinds of processing as an axis position control device. The RAM 103 stores software variables and the like required at this time, and the command storage unit 1 in this RAM is stored.
A position / speed command value is stored in 04. Position detector I
F120 is a position detector 51-connected to each motor.
It is composed of circuits 121 to 124 which receive the position detection analog signals E1 to E4 from 54 and digitize them by a known technique. The servo amplifier IF130 is composed of serial communication IF circuits 131 to 134 for transferring the current command values Ir1 to Ir4 to each axis servo amplifier at a predetermined timing.

Next, the operation of the microprocessor 101 will be described with reference to FIG. Now, it is assumed that the i-th position command value Prm, i for the servo motor that drives each axis is transferred to the axis position control device 1 at a predetermined timing and is in the j-th position control cycle. Inside the axis position control device 1, the microprocessor 101 monitors the update of the time count data CNT by polling and determines whether the value is 0 (step N1 in FIG. 3). If CNT = 0, the process proceeds to step N2 to start the position control processing PC for all axes. If CNT = 1 to 4, proceed to Step N6, where CN
Speed control process SCm for the motor corresponding to the value of T
(M = 1 to 4) is executed. Since CNT = 0 now, the i-th four position command values Prm, i (m = 1 to 4), which is the process of step N2, are read. Next, as in the prior art, four position detection values Pam,
I, j (m = 1 to 4) is read (step N3 in FIG. 3).
From these data, the microprocessor 101 uses the speed command values Vrm, i, j (m = 1) for all the motors (four).
~ 4) is calculated by a known method (step N4 in FIG. 3),
The data is stored in the command value storage unit 104 (step N5 in FIG. 3).
When the storage is completed, the position control process PC for all motors, which is the process of CNT = 0 with j = 0, is completed. Then CNT
When = 1, the microprocessor 101 sequentially executes the speed control processing for the steps after step N6 in FIG. 3, that is, for each axis (motor). First, the servo motor identification subscript k is determined according to the value of CNT which axis is to be processed (step N6 in FIG. 3). In this case, k = CNT = 1 and the speed control process SC1 for the first axis is executed. First, the speed command value Vr1, i, 0 for the first axis is read from the command value storage unit 104 by the same method as in the prior art (step N7 in FIG. 3). Next, the speed detection value Va1, i, 0 of the first axis is read (step N8 in FIG. 3). Next, the current command value Ir1 is calculated in the same manner as in the prior art (step N9 in FIG. 3). This current command value is the servo amplifier IF
The data is transferred to the first-axis servo amplifier 31 via 131 (step N10 in FIG. 3). Based on the current command value Ir1, the first-axis servo amplifier 31 finally generates a phase voltage to be applied to the servo motor 31 by a known technique. By applying this voltage, a drive torque is generated in the servo motor 31, and the drive load is drive-controlled at a desired position and speed. The microprocessor 101 completes the first axis speed control processing SC1 upon completion of the transfer of the current command value, and waits for the next update of the time count data CNT. Below, timing data C
In the case of NT = 2-4, the 2nd-4th axis speed control processing S
C2 to SC4 are executed in the same manner as the speed control process SC1 for the first axis. In the above procedure, the position control processing PC for all axes and the speed control processing SC for the first to fourth axes
When 1 to SC4 are completed, the control process at j = 0 is completed. In the next control processing cycle (j = 1),
The position command value Prm, i is set in the same procedure as the control process for j = 0.
Position control processing PC for all axes based on
The speed control processes SC1 to SC4 for the axis are executed.
After that, similarly, the control processes of j = 2 and 3 are executed. When the control process of j = 0 to 3 is completed, j is reset to 0, and the next position command value Prm, i + 1 is prepared for transfer. The control operation of the shaft position control device 1 is executed as described above.
A time chart of this is shown in FIG. 4, in which Tsc is a speed control cycle (clock data CNT update cycle).
, Tpc represents a position control cycle, and Tpr represents a position command cycle. As described above, in the present invention, the position control processing 1
Since the speed command values for all axes are newly calculated each time,
For example, in the interrupt processing of j = 2 in the i-th position command cycle, Vm, i, 2 (m = 1 to 4) is calculated as a new speed command value by the all-axis position control processing PC, and each axis speed control is performed. Process SC1
In SC4, the following data are used as the speed command value and the speed detection value data, respectively. SC1 ... Vr1, i, 2 and Va1, i, 2 SC2 ... Vr2, i, 2 and Va2, i, 2 SC3 ... Vr3, i, 2 and Va3, i, 2 SC4 ... Vr4 , i, 2 and Va4, i, 2 In other words, the speed command value based on the latest position command value (= Prm, i) is calculated in the same position control process for all axes, so the latest position problematic in the prior art There is no time difference between updating the speed command value based on the command value. That is, the speed control processing can be performed for all the motors using the latest speed command value within the same position control cycle. However, as in the prior art, the current command value for only one axis is calculated in one speed control process, so there is still a difference in the generation time of the current command between the motors within the same position control cycle. Synchronization error due to remains. However, this time difference is, for example, 3 between the first axis and the fourth axis.
This is the speed control period Tsc, which is 6 of the position control period Tpc.
It is only worth the price. Therefore, although it depends on the setting of the control cycle, it can be reduced to about 1/6 of the time difference in the conventional technique. (See Figure 4). FIG. 5 is a diagram showing a synchronous operating position command error for the shaft position control device of the above-described embodiment, and the view of the diagram is the same as that of FIG. 11 for explaining the synchronous operating position command error in the shaft position control device according to the prior art. is there. When the same synchronous operation position command value as in FIG. 11 is given (that is, the speed command curves of the first and fourth axes in FIG. 5 are the same as those in FIG. 11), the speed command based on the synchronous operation position command value. The curve rises immediately after execution of SC1 in the process of INT = 0 of j = 0 in the i-th position command cycle in the first axis, and j = 0 in the i-th position command cycle in the fourth axis. Immediately after the execution of SC4 during the processing of INT = 0. Therefore, the time difference between them is 0.6 times the actual position control period Tpc as described above. As in the case of FIG. 11, when the acceleration / deceleration unit amount is 1 m / S · S, the position command cycle Tpr is 10 ms, and the position control cycle Tpc is 2.5 ms, the position command error ERp in FIG. 5 is about 5 μm. 1 compared to
It has decreased to / 6.

Timekeeping data CN in the first embodiment described above
The object of the present invention can be achieved by using a hardware interrupt signal instead of T. FIG. 6 is a hardware configuration diagram showing the shaft position control device 1 of the second embodiment of the present invention made from this viewpoint, and FIG. 7 is an operation time of the shaft position control device 1 of the second embodiment of the present invention. It is a chart. Items not mentioned in the following description of the second embodiment of the present invention are the same as those of the first embodiment of the present invention described above.
6, in the interrupt signal generator 107 that generates an interrupt signal corresponding to the position control / speed control cycle from the hardware clock signal CLK, an interrupt signal Int_L having a cycle at least equal to the speed control cycle Tsc in FIG. ,
In synchronization with this, an interrupt signal Int_H having a cycle equal to the position control cycle Tpc in FIG. 4 is generated. To ensure that the speed command value based on the latest position command value is executed in the same position control process for all axes, that is, the position control process interrupt process is not interrupted by the speed control interrupt process. The interrupt level (interrupt priority) of the interrupt signal Int_H is set higher than that of the interrupt signal Int_L. As a result, even if Int_H and Int_L compete with each other, Int_
The H interrupt is prioritized and the priority processing is guaranteed. Therefore, these interrupt signals Int_H and Int_L are input to the interrupt signal selection unit 108, the priority is determined according to the information from the motor number storage unit, which will be described later, and the speed control processing interrupt signal INTv and the position control signal. When the interrupt signal INTp is input to the microprocessor 101 and the control processing of CNT = 0 and CNT = 1 to 4 in the first embodiment is performed, the same effect as in the first embodiment can be obtained. At this time, since Int_H and Int_L are in a synchronous relationship, the speed control process in the speed control cycle in which the position control process PC for all axes is executed is a dummy process and substantially no speed control process is performed for any axis ( This dummy speed control process is expressed as SC0). That is, the speed control interrupt processing SC0 in the speed control cycle in which the PC is executed performs only the interrupt end processing, from SC1 to S.
C4 is the step N6 to FIG. 3 corresponding to each axis.
The interrupt end process is performed with N10. FIG. 7A shows the above operation in a time chart. Further, in the present embodiment, the axis control executed based on the selection result of the interrupt signal selection unit can be selected from the multi-axis position control and the single-axis position control. That is, in the one-axis position control device, in addition to shortening each control cycle as a measure for obtaining higher control performance, execution of the speed control loop, which is a minor loop, is prioritized over the position control loop, and speed control is performed. Usually, the interrupt level of the processing interrupt signal INTv is set higher than the interrupt level of the position control interrupt signal INTp. In order to enable the axis position control device for controlling a plurality of axes according to the present invention to be used as such a one-axis position control device, the RAM 103 is provided with a motor number storage unit 109 for storing the number of motors to be controlled. The number-of-motors data given by a known method is stored here. When the number of motors is 1, the interrupt signal selection unit 108 outputs the two types of interrupt signals Int_H and Int_L generated by the interrupt signal generation unit 107 and the two types of interrupt signals input to the microprocessor 101. Included signal INTv
And INTp. Specifically, when the number-of-motors data is 1, Int_H is set to I in order to lower the priority of the position control execution interrupt signal INTp than the speed control execution interrupt signal INTv.
Int_L is set to INTp in NTv, and when the number of motor data is plural, the position control execution interrupt signal INTp
Int_L to INTv in order to make the priority level of INTv higher than that of the speed control execution interrupt signal INTv.
Is input to the microprocessor 101 as INTp. FIG. 7B shows a time chart of the operation when the number-of-motors data is 1. In FIG. 7 (b),
SC1 to SC4 indicate the processing order to be executed for a single motor, the speed control processing is executed prior to the position control processing, and the i-th speed control processing is performed with the i-1th speed command value. Although used, it does not cause a large position command error because it continuously controls a single motor with a short control cycle. Further, since the speed control process is executed prior to the position control process, the dummy process SC0 as shown in FIG.
Is unnecessary. In this way, by selecting the priority of processing by the interrupt signal selection unit, it is possible to perform accurate multi-axis control according to the application and also perform single-axis control by the same control device. The versatility of the device can be improved.

Besides the above-described embodiments of the present invention, the following modifications may be made without departing from the spirit of the present invention. A1. A motor number setting unit for setting the number of servo motors to be controlled, a processing time storage unit for storing processing time for one position control and one speed control for one servo motor, the number of servo motors and the processing time. To a position control cycle determining unit that determines the position control cycle Tpc, and the position control cycle Tpc is changed according to the number of servo motors. The position control cycle determination unit determines the position control cycle Tpc as follows. In the case of FIG. 7A, Tpc = Tsc * (number of motors + 1), where Tsc is the longer of (position control processing time for one motor * number of motors) and speed control processing time for one motor. This is a speed control cycle obtained by adding a margin time to the other time. In the case of FIG. 7B, Tpc = (Ts
c * number of motors). A2. Servo motor number storage section for storing the number of servo motors to be controlled, processing time storage section for storing the processing time for one position control and one speed control for one servo motor, and position for storing the position command cycle A command cycle storage unit and a control count determination unit that determines the number of position control and speed control within one cycle of the position command from the number of servo motors and the processing time are provided, and the position command cycle Tpr The axis position control device is characterized by changing the number of times of position control and speed control within one cycle. The control frequency determining unit determines the number of times of position control and speed control in one cycle of the position command from the position command cycle Tpr given in advance and the position control cycle Tpc determined by the number of motors shown in the item A1.

As described above, according to the present invention, the position control section of a plurality of units of one microprocessor has the latest position in the same position control cycle according to the data from the time count counting section. The speed command is calculated for all the motors based on the command value, and the multiple-unit speed control unit sequentially performs the speed control process for all the motors based on the speed command value. A large synchronous operation position command error can be avoided. Therefore, it becomes possible to bring the command locus along which the axis actually moves closer to the ideal command locus, and the machining accuracy can be improved. The interrupt signal selection unit selectively outputs an interrupt signal input from the outside according to the number of motors controlled, and the position control processing of the motor by the multiple unit position control unit and the multiple unit speed control unit Since the speed control process is performed within the same position control cycle, a large synchronous operation position command error caused by a command value level due to a time difference in processing time can be avoided by using a hardware interrupt signal. Therefore, it becomes possible to bring the command locus in which the axis actually moves closer to the ideal command locus, and the machining accuracy can be improved by the control using the hardware clock. Further, when the number of motors to be controlled is 1, among the interrupt signals input to the interrupt signal selection unit, the priority of the position control execution interrupt signal for executing position control is executed for speed control. The priority of the speed control execution interrupt signal is set lower than that of the speed control execution interrupt signal, and when the number of motors is plural, the priority of the position control execution interrupt signal is set higher than the priority of the speed control execution interrupt signal. Therefore, it is possible to avoid a large synchronous operation position command error that occurs in the command value level due to the time difference in processing time, and use a position control device that controls multiple axes by changing the priority as a one-axis position control device. Therefore, the versatility of the control device can be improved.

[Brief description of drawings]

FIG. 1 is a conceptual functional block diagram showing a first embodiment of an axis position control device according to the present invention.

FIG. 2 is a hardware configuration diagram showing a first embodiment of an axis position control device according to the present invention.

FIG. 3 is a flowchart showing the operation of the first embodiment of the shaft position control device according to the present invention.

FIG. 4 is an operation time chart of the first embodiment of the shaft position control device according to the present invention.

FIG. 5 is a diagram showing a position command synchronization error in the shaft position control device according to the embodiment of the present invention.

FIG. 6 is a hardware configuration diagram showing a second embodiment of the shaft position control device according to the present invention.

FIG. 7 is an operation time chart of the second embodiment of the shaft position control device according to the invention.

FIG. 8 is a conceptual functional block diagram showing a conventional shaft position control device.

FIG. 9 is a flowchart showing the operation of a conventional shaft position control device.

FIG. 10 is an operation time chart of a conventional shaft position control device.

FIG. 11 is a diagram showing a synchronous operation position command error for a conventional shaft position control device.

[Explanation of symbols]

 1 Axis Position Control Device 2 Multiple Units Position Control Unit 3 Multiple Units Speed Control Unit 13 Position Detection Unit 16 Speed Detection Unit 21-24 Torque Control Device 31 Servo Amplifier 41 Servo Motor 51-54 Position Detector 106 Time Counting Unit

Claims (2)

[Claims] 1. A shaft position control device that executes position control and speed control of at least one motor based on a position command value that is input, and a time signal generation unit that generates a time signal at regular intervals. , A time count counter that counts the number of times the time count signal is generated in a position control cycle and generates time count data at a fixed interval, and the time count count section generates the first time count data in a predetermined position control cycle Sometimes, a plurality of unit position control units that perform position control processing to calculate a speed command value based on the corresponding position command values for all motors, and the timekeeping based on the speed command values generated by the plurality of unit position control units. A plurality of speed control units that sequentially perform speed control processing for all motors within the position control cycle in accordance with the time count data generated by the frequency counting unit; Axis position control apparatus characterized by having. 2. An axis position control device for executing position control and speed control of at least one motor based on an input position command value, and generating an interrupt signal for generating a plurality of interrupt signals with different cycles. Section, a motor number storing section for storing data on the number of motors to be controlled, and a position control execution interrupt signal and speed for executing position control from the interrupt signals according to the contents stored in the motor number storing section. An interrupt signal selection section that selects a speed control execution interrupt signal to execute control and outputs with prioritization, and if a position control execution interrupt signal occurs, all within a predetermined position control cycle. A plurality of unit position control section for performing position control processing of the motor, and a plurality of unit speed control section for sequentially performing speed control processing of all the motors within the position control cycle when a speed control execution interrupt signal is generated, To If the number of motors is 1, the interrupt signal selection unit lowers the priority of the position control execution interrupt signal below the priority of the speed control execution interrupt signal. In the case of a plurality of axes, the position control execution interrupt signal has a higher priority than the speed control execution interrupt signal.