JPH0619661B2 - Distributed numerical controller - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to an apparatus for realizing synchronous operation of each axis in a distributed numerical control apparatus in which a numerical control apparatus is distributed and arranged for each axis of a machine tool, a robot or the like, or a complex thereof.

[Prior art]

As shown in FIG. 1, the distributed type numerical control device means that each numerical control device 3 is operated by transferring the movement data to the numerical control device 3 for driving and controlling the axis servo system 2 by the upper axis group manager 1. This is a device for independently controlling each axis servo system 2. At present, such a device has not been put into practical use because there is no means for performing synchronous operation between the axes. If the above system is operated without the means for synchronizing, the error of the calculation speed of each numerical control device 3 influences the locus, and the target locus of movement cannot be realized, and it is attempted to correct it for each minute section. Then, in the worst case, mechanical vibration may be induced. In view of the above points, the applicant of the present invention has proposed a device for realizing the synchronous operation of distributed numerical control devices in Japanese Patent Application No. 58-756.
Served as 08. Japanese Patent Application No. 58-75608 receives the data for axis movement issued by one axis group controller, and one mechanical movement assigned to itself by the pulse output from the speed commander in the own device. In a distributed numerical control device having a plurality of numerical control devices for controlling the drive of an axis, the axis group manager and a common transmission line connecting all the numerical controllers are provided, and the axis group manager has the A unit for transferring data to the numerical control device by sending a common frame designating all of the numerical control devices and a unique frame designating any one to the transmission path is provided, and each of the numerical control devices is provided with: Start by the buffer register that temporarily stores the data taken from each unique frame and the data stored in the buffer register each time the common frame is received. Then, a speed command unit to complete the operation of the speed command unit until receiving the common frame again Te is characterized in that the provided. An example of Japanese Patent Application No. 58-75608 will be described below. Here, an example in which three numerical control devices are provided and three-axis synchronous operation is performed will be described. First, a frame will be described. Generally, when data is transferred from a master station (here, axis group manager) to a plurality of slave stations (here, numerical controller), a high level data link control (hereinafter referred to as HDLC) ) Format (J
IS standard C-6363) is used. The HDLC transfer format is shown in FIG. Between the flag indicating the start and end of one cycle, address, command, data,
A cyclic redundancy check is included. The one cycle is called a frame, and this frame is continuously transmitted. In this embodiment, this frame is transferred by one common frame corresponding to all numerical controllers and three unique frames corresponding to individual numerical controllers to make one transfer pattern.
A cycle is constructed. This state is shown in FIG. 3, where F _n -1, F _n -2, F _n
-3 is unique frames _{is F} n -0 common frame. _Fn- 1, _Fn- 2, and _Fn- 3 are each numerical control device NC.
1, NC2, NC3, respectively laid information corresponding _{individually, F} n -0 is the information corresponding to the common to all the numerical controller NC1~3 rests. Next, the structure of each numerical controller will be described. As shown in FIG. 4, a buffer register 4 for temporarily storing received data is provided. The speed commander 6 sends a desired amount of pulses to the servo controller 5 in a unit time, and can be realized by the circuit shown in FIG. 5, for example. The CPU in the CPU section 7 is directed to the data bus (D ₇ ).
And speed data (D _{0 to} D ₅ ) are set and a WRSG signal is issued, the data becomes the input data of the binary rate multiplier 9 written in the D flip-flop 8 and the RS flip-flop 10 To enable the binary rate multiplier 9. The binary rate multiplier 9 outputs EO after counting 64 pulses of SP and outputs RS flip-flop 1
Reset 0, disable yourself. During this time, the pulse for the input data is directed by D ₇ ,
Output EP or -EP. This pulse number is the movement amount. Next, a specific operation will be described with reference to FIGS. 6 and 7. The address of the frame F _n −1 is “00000001”
Then, it is assumed that the numerical control device NC1 is designated.
Therefore, when NC1 receives the frame F _n -1, it fetches the command and data following the address into the buffer register. NC2 and NC3 are naturally ignored. The address of the frame _F n -2 "00000010"
Then, it is assumed that the numerical control device NC2 is designated.
Thus NC2 command following the address and receives the frame F _n -2, captures the data in the buffer register. NC1 and NC3 are naturally ignored. The address of the frame _F n -3 "00000100"
It is assumed that the numerical controller NC3 is designated.
Therefore, when the frame F _n -3 is received, the NC 3 fetches the command and data following the address into the buffer register. NC1 and NC2 are naturally ignored. Between the above and the above, the NCs 1 to 3 are operating by the data acquired in the previous cycle. Frame _F n -0, the total numerical controller NC1~NC3
The NC1 to NC3 receive the command and data following the address in common. During this acquisition, NC1 to NC3 are still operating with the data acquired in the previous cycle. When the acquisition is completed, the contents of each buffer register are written in the speed command device and the speed command devices are activated at the same time. However, each N is set so that the speed command calculation in the previous cycle is completed by just before the completion of the acquisition.
Adjust the calculation speed of C. The above-described operation would make it possible to operate the axes in perfect synchronization. The reason will be described with reference to FIG. In the first place, the cause that could not be completely synchronized in the past is that each N
This is because there is an error in the calculation speed of C. However, in the present invention, since the operation start time 11 is completely synchronized for each transfer cycle, an error is absorbed within one cycle,
Does not affect the movement of the axis. This is because the time required for one transfer cycle is about several milliseconds, and the variation of the clock within that time is within several microseconds. This order has no effect on the operation of the servomotor that drives the axis. Also, even in the pause time until the restart, the speed commander only pauses and is not related to the motor. The simultaneous control of three axes has been described above, but the present invention can be performed for more than three axes. As described above, according to Japanese Patent Application No. 58-75608,
Since a large number of numerical control devices are synchronized in each data transfer cycle, it is possible to perform multi-axis perfect synchronous operation, which makes it possible to control robots, machine tools, transporting machines, etc. as a whole, and to achieve advanced FA (Factory automation)
Can be realized.

[Problems to be Solved by the Invention]

However, since the HDLC communication accuracy is not 100% reliable at present, there is a possibility that the HDLC may not be completely synchronized. That is, a transmission error is not a little and can occur, and in that case, there is a risk that the speed commander remains stopped. Therefore, the present invention relates to Japanese Patent Application No. 58-
It is intended to solve the problem of 75608.

Means for Solving the Problems The features of the present invention are found in Japanese Patent Application No. 58-75608.
A timer and a transmission data estimation unit are provided in each numerical control device, and the timer is started each time a common frame is received, and the next common frame is not received even though one cycle time has elapsed. In this case, the speed commander is activated by the data estimated by the transmission data estimation unit when the timer counts up.

[Action]

With the above means, the timer complements each other to enable complete synchronization.

【Example】

The details will be described below. FIG. 9 shows a block diagram of the present invention. In the figure, reference numeral 11 is a timer, and it is assumed that a time longer than the cycle of receiving the common frame by a minute time is set in advance. Reference numeral 12 is a transmission data estimation unit that estimates the previously received data as the current transmission data. Alternatively, the average value of the reception data of the previous several times may be estimated as the transmission data of this time. However, the transmission data estimation unit 12 outputs the estimated value to the speed command device 5 and activates it only when the timer 11 counts up. With such a configuration, it is possible to avoid a transmission error and prevent the speed command device from stopping. However, the CPU unit 4 can be substituted for the timer and the transmission data designation unit. The specific operation will be described with reference to FIG. As shown in the figure, the timer is set to be slightly longer than the common frame reception period T, and at the same time (t
Start timing at point a). If no transmission error occurs, it is reset when the next common frame is received (at time tb). When a transmission error occurs, when the timer counts up (t
At time c), the speed commander is activated with the estimated data.
If no transmission error occurs in the next cycle, it is reset at time tb and returns to normal.

【The invention's effect】

As described above, according to the present invention, it is possible to prevent the speed commander from being stopped due to a transmission error. Further, if the transfer data designating section is constructed so as to independently generate data, it is possible to realize a system without a transmission system or a distributed numerical control system in which only a predetermined axis is operated independently regardless of transmission.

[Brief description of drawings]

FIG. 1 is a conventional example, FIG. 2 is a transfer format, FIG. 3 is an example of a format sequence of Japanese Patent Application No. 58-75608, FIG. 4 is a configuration example of a numerical control device of Japanese Patent Application No. 58-75608, and FIG. The figure shows a configuration example of the speed commander in Japanese Patent Application No. 58-75608.
6, 7 and 8 are diagrams for explaining the concrete operation of Japanese Patent Application No. 58-75608, FIG. 9 is a structural example of the numerical controller of the present invention, and FIG. 10 is a concrete example of the present invention. It is a figure explaining operation.

Claims (3)

[Claims] 1. A drive of one mechanical movement axis which is assigned to itself by a pulse output from a speed commander in its own device by receiving data for axis movement issued by one axis group controller. In a distributed numerical control device having a plurality of numerical control devices for controlling, a common transmission line connecting the axis group manager and all the numerical controllers is provided, and the numerical group controller is provided with the numerical controller. In addition to providing a means for transferring data to the numerical control device by sending a common frame that specifies all of the above and a unique frame that specifies any of them to the numerical control device, each numerical control device is provided with a count-up time. If the common frame is set to be slightly longer than the common frame reception cycle, the common frame is received, and the common frame is received again within the count-up time, the timer count Timer for resetting the frame, a buffer register for temporarily storing the data fetched from each of the unique frames, and a common frame for starting again with the data stored in the buffer register each time the common frame is received. A speed commander that completes the operation of the speed commander by the time of receiving, and if the common frame is received and the common frame is not received again within the count-up time, the speed commander estimates the data. A distributed numerical control device, comprising: a transmission data estimation unit for outputting to a. 2. The distributed numerical control apparatus according to claim 1, wherein the transmission data estimation unit estimates the previously received data as the data to be received this time. 3. The distributed numerical control apparatus according to claim 1, wherein the transmission data estimation unit estimates the average value of the reception data of the previous several times as the data to be received this time.