KR19990079125A - Implementation of numerical control device using single central processor - Google Patents

Abstract

The present invention relates to a method of implementing a numerical control apparatus using a single central processing unit, and more particularly, to a method of designing a numerical control apparatus using a single central processing unit, A human-machine interface working phase; A Basis work step of receiving data from the human-machine interface work step and performing a translation of the program; A servo operation step of receiving data from the Basis operation step and generating an actual motion trajectory; A position control operation step of receiving data from the servo control operation step and performing motion control; In the real-time multiprocessing (RT-OS) environment, each independent task constituting the numerical control apparatus such as the logic control step of receiving the input data from the human-machine interface work step and the input / output data from the machine, It is possible to reduce the hardware cost of the overall system configuration by configuring it as an independent thread.

Description

Implementation of numerical control device using single central processor

The present invention relates to a method of implementing a numerical control apparatus using a single central processing unit, and more particularly, to a method of implementing a numerical control apparatus in which each function of all system components is software in a task form and controlled by a single central processing unit .

Background Art [0002] In recent years, numerical control devices have been implemented in a new form using a PC due to the development of a high-speed, high-performance and real-time operating system (RT-OS) of a central processing unit (hereinafter referred to as CPU).

In other words, unlike the existing numerical control system consisting of MMI processor, instruction interpreter, interpolator, position controller and PLC processor implemented with separate CPU and hardware, multi-tasking processing of many programs under real-time environment As a result, an attempt has been made to implement the above functions in a software form as a single CPU.

As shown in FIG. 1, a typical numerical control device is a Man-Machine Interface (hereinafter referred to as MMI) that displays an operating state of a machine and supports an operation of a user to provide an interface environment between a user and a machine A programmable logic controller (hereinafter, referred to as a PLC) 20 for programming and controlling data input by the user through the MMI 10 and data input on the operation state of the machine, And a servo mechanism (30) for performing motion control.

The operation of a general numerical controller having the above configuration will now be described.

A user applies a control input signal through the MMI 10 and operates the execution program by applying the control input signal. And displays the operating state of the machine through the MMI (10).

The PLC 20 receives input data and operation state data of the machine through the MMI 10 and controls the received data.

The servo mechanism 30 operates according to the execution program from the MMI 10 to perform the work.

Each of the processors in the MMI 10, the PLC 20 and the servo mechanism 30 performs independent tasks, and each of the independent processors can communicate with each other using a bus-level, Processors communicate with each other using a single shared memory device (Shard-memory), thereby realizing a harmonic operation between the respective processors under a real-time environment.

However, the conventional method of implementing the numerical control apparatus has a limitation in lowering the price of products by requiring the MMI 10, the PLC 20, and the servo mechanism 30 to be provided with arithmetic functions and communication functions.

In addition, the conventional numerical control apparatus is configured in hardware, so that when a new function is added, the entire system must be reconfigured.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a servo control task, a PLC task, an MMI task, a position control task, ), And implementing it by using a single CPU, thereby providing a method of implementing a numerical controller that can reduce cost in terms of hardware.

It is another object of the present invention to provide a method of implementing a numerical control apparatus that can be easily optimized when a system is changed by configuring the tasks constituting the numerical controller in software.

1 is a control circuit block diagram briefly showing a configuration of a general numerical controller,

2 is a block diagram of a control circuit including each task of the numerical controller according to the present invention,

3 is a flowchart of an initialization routine of the system configuration of the numerical controller according to the first embodiment of the present invention,

FIG. 4 is a diagram showing an occupation distribution chart of a central processing unit (CPU) of each task according to the second embodiment of the present invention,

5 is a configuration diagram of a loop driver using a module header according to the third embodiment of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

100: human-machine interface (MMI) 200: memory

500: Interface board 510: Analog & digital interface

520: Analog & Digital Input / Output Devices

530: buffer memory 600: peripheral device

700: driving unit 800: motor

900: central processing unit (CPU)

A first aspect related to a control method of a numerical controller according to the present invention for solving the above object is a human-machine interface work step for displaying an operating state of a machine and supporting an operation of a user to perform an interface between a user and a machine A basic operation step of receiving data from the human-machine interface operation step and performing a translation of the program and performing interpolation of the machine; and a control step of receiving data from the basis operation step, A position control operation step of receiving data from the servo control operation step and performing a position control and a work plan of the whole system, Receives the control input data output from the servo control operation unit And a programmable logic control job step for performing control of the system.

According to a second aspect of the present invention, there is provided a control method for a numerical control apparatus, comprising: a script file reading step of reading a system script file (Script file) A hardware initialization step of initializing the hardware by checking system interrupts and a buffer memory after the step, and a task generating step of sequentially generating each position control task, the servo control task, the programmable logic control task, and the basis task after the hardware initialization step An input / output script file reading step of reading an input / output script file after the task generating step, a routine table inserting step of loading execution modules and inserting routine tables after the input / output script file reading step, It is determined whether or not the initialization process is successful. Results When the initialization process is determined to be successfully accomplished by any task running phase where tasks are performed on a periodic basis.

According to a third aspect of the present invention, there is provided a control method of a numerical control apparatus, comprising: an execution frequency setting step in which a user arbitrarily sets a frequency of execution for each task; and a determination step of determining whether the execution frequency is set And a transfer step of transferring the right to use the control means to another task when the set number of times is executed.

A fourth feature of the control method of a numerical controller according to the present invention for solving the above-mentioned problems is that a routine table is defined in a data segment of each task, a system boot-up is performed on the defined routine table, The routine table is created according to the priority of each routine, and periodic numerical control routines are executed using the routine table when a normal system is loaded.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

2 is a system configuration diagram showing a schematic configuration of a numerical control apparatus expressed by software, that is, each task of the numerical control apparatus.

A human-machine interface (hereinafter referred to as MMI) 100 is responsible for the processing of the MMI task 110 that displays the status of the machine and supports the user's operation to provide an interface between the user and the machine. The MMI is operating under a WINDOW operating system.

A memory 200 for storing data input from the MMI 100 and storing data input from the outside includes a CNC (Computerized Numerical Control) operation 300 for processing numerical values by a computer, And a PLC job 400 for controlling and processing data input from the PLC job 400 are stored.

The CNC operation 300 includes a position control task 310 for performing position control and overall scheduling at every sampling time when an external real time clock on the interface board 500 generates an interrupt every predetermined sampling time, A servo control task 320 controlled by the scheduling of the position control task 310 to generate a motion locus, and a Basis task 320 for performing the MMI interface and interpolation.

The PLC job 400 comprises a PLC task 410 for inputting data from the MMI 100 and operating the machine by input / output signals from the machine.

Also, a real-time operating system (RT-OS) is embedded in the memory 200 (not shown).

An interface board 500 for providing an interface between a user and a machine is provided with a digital & analog input / output device 520 for inputting / outputting digital and analog signals, an A / D converter 520 for converting a signal input / output through the digital & A D / A converter 510, and a buffer memory (VMI) 530 for temporarily storing the input / output signal and transmitting the input / output signal safely at high speed.

The peripheral device 600 includes an OP-PANEL and an HDD (hard disk driver) and an FDD (Floppy disk driver), which are auxiliary storage devices capable of backing up various data by interfacing with a bus, a VGA .

A driving device 700 driven by a control signal outputted through a digital & analog input / output device 520 for inputting and outputting digital and analog signals is connected to the interface board.

And a motor 800 operated by a driving signal of the driving device 700 is connected to the driving device.

The memory 200, the interface board 500, and the peripheral device 600 are connected to a CPU 900 that processes a control program and various data through a bus line.

The operation of the numerical controller according to the present invention will be described in detail with reference to the first embodiment.

FIG. 3 is a flowchart illustrating a process of configuring a software configuration of a numerical control device for a machine tool according to the first embodiment, and is a method of configuring an entire system using a configuration script file.

If the numerical controller is activated in step S1, the system script file for configuring the entire system is read.

In step S2, a hardware initialization operation for checking the system interrupt, the buffer memory 530, and the like is performed.

In step S3, the position control task 310, the servo control task 320, the PLC task 410, and the basis task 330 are sequentially generated.

In step S4, the input / output script file after the generation of each task is read.

In step S5, the execution modules of the respective tasks are loaded and the routine tables for program execution are inserted.

In step S6, it is determined whether the initialization process is successful. If the determination result is successful, the process proceeds to step S7.

In step S7, all the tasks are executed periodically, and when all the tasks are completed, the boot-up processing is terminated.

On the other hand, if the initialization process is not successful in step S6 (NO), the process proceeds to step S8.

In step S8, the boot-up is interrupted and the process proceeds to the operating system control mode.

FIG. 4 shows an example of a timing when each of the tasks generated in FIG. 3 is executed as a second embodiment, and is a method for allocating an arbitrary execution interval in addition to basic task switching provided by a real-time operating system for each task.

In the method of implementing the soft numerical control device, the periodical execution time of each task may be changed according to the performance of the control object or the CPU 900 to be applied, so that the user can arbitrarily set the frequency of execution of the individual task.

In FIG. 4, the solid line portion of each task indicates a state in which the CPU 900 is in the open state, that is, a state in which it is executed.

The position control task 310 assigns the highest priority according to the importance of the processing task and is executed by the reference interrupt signal periodically generated by the timer. When execution is completed, the position control task 310 is assigned the next highest priority And transfers the usage right of the CPU 700 to the servo control task 320.

In the second embodiment, the period of the servo control task 320 is twice the period of the position control task 310.

The reason why the servo control task 320 is executed once every time the position control task 310 is executed is that the position control task 310 receives the position information interpolated from the servo control task 320 and outputs the position control task 310 ), Because it performs its own interpolation.

If the cycles of the position control task 310 and the servo control task 320 are the same, the position control task 310 does not perform the interpolation.

Similarly, when the execution of the servo control task 320 is completed, the CPU 900 is transferred to the PLC task 410 having the highest priority.

At this time, if the position control task 310 or the servo control task 320 whose priority is assigned higher prior to the execution of the PLC task 410 is to be pointed to the CPU 900, the execution of the PLC task 410 And transfers the CPU 900 license.

The above operation principle is for the reason that a plurality of tasks are processed under a real-time operating system so that they are executed according to the urgency and importance of the processing, the predetermined priority and periodicity at design, and the period set by the user.

The MMC task 110 having the lowest priority is set to have no periodicity so that the priority tasks that are periodically executed are executed and the CPU 900 is transferred at the remaining time.

The operation of the software implementation method of the numerical controller will be described as follows.

The following variables are used to arbitrarily control the task execution frequency.

Task_Status: An indication of the status of the task.

Idle (= 0) value if the previous execution is completed.

If the previous execution is not completed, it has Busy (= 1) value.

Task_Set_Counter: Set the task execution frequency.

= Task_Loop_Time% Position_Sampling_Time

Task_Actual_Counter: Increase on completion of every task.

Position_Task ()

{

[Instructions related to motion control;

Task1_Actual_Count = Task1_Actual_Count% Task1_Set_Counter;

if (Task1_Actual_Count = 0)

{

if (Task1_Status = Busy)

return Busy

else

[Send semaphore to activate Task1;]

}

Task2_Actual_Count = Task2_Actual_Count% Task2_Set_Counter;

if (Task2_Actual_Count = 0)

{

if (Task2_Status = Busy)

return Busy

else

[Send semaphore to activate Task2;]

}

..............

}

The above-configured code is analyzed as follows.

For example, when the sampling time of the position control task designed as the interrupt task is 1 (ms) and the task loop time (Task_Loop_Time) of the task 1 is set to 4 (ms), the Task_Set_Counter becomes 4, It means that Task 1 is executed once every 4 times of task.

The task 2 may also be configured to execute a series of self-tasks when the position control task 310 generates an interrupt, and then use the semaphore to wait for a license of the CPU 900, The process goes through a series of processes.

Here, the execution cycle of each task is set to be as short as possible due to the characteristics of the user, so that a high control performance can be assured.

FIG. 5 is a block diagram showing the configuration of a loop driver using a module header according to the third embodiment. In general, functional modules called NC kernels are automatically managed and sequentially executed It is a way of giving.

The function module header defined here replaces the Compiler specific funtion header of the object file by a specially designed system utility program. Therefore, all functional modules consist of 16Byte module header and following module code section.

Table 1 below shows the basic structure of the module header defined for each function.

Table. One

Identity Type Module priority Pointer to module entry Module length Version Dummy1 Dummy2 1 Byte 1 Byte 2 Bytes 6 Bytes 2 Bytes 1 Byte 1 Byte 2 Bytes

Identity: Identification of the module file header

Type: Type of module file

0 × CNC module for 11 bases tasks

0 × 12 CNC module for servo control task

0 × 14 CNC module for position control tasks

0 × 1F CNC interrupt routine

0 × 20 PLC module

0 × 2F PLC interrupt routine

Module priority: Specify the slot number in the routine table consecutively

Pointer to module entry: Call the address of the code at offset

Module length: The length of the module containing the module header

Dummy 1: 0 × Scheduled future use of FF

Dummy 2: 0 × Schedule forward use at FFFF

These functional modules are loaded on the memory segment assigned to each task during system boot-up regardless of the execution order. If more than one existing function module exists in the secondary storage, the system software loads the latest version using the module header of the function module loaded in the memory segment.

The operation of the software implementation method of the numerical controller will be described as follows.

In order to sequentially execute function modules loaded on the memory segments according to the assigned priority, a routine table is defined in a data segment of each task.

When the routine table is defined, the system software makes a task and a routine table at the time of system boot-up.

When the routine table is completed for each task, numerical control routines are executed sequentially and periodically using a routine table.

As described above, according to the present invention, a built-in operation controller (Embeded motion controller) is replaced with a simple analog interface board or a digital interface board, and the functions of the built-in operation controller and the MMI function are processed by a single CPU. The cost can be reduced.

By configuring the numerical controller in software, it is easy to dynamically optimize the system according to the change of the application target.

Claims (4)

In the realization of a numerical controller in software by constructing each part constituting an NC in a real-time multiprocessing environment using a single CPU as an independent thread, A human-machine interface work step for displaying the operating state of the machine and supporting the user's operation to perform an interface between the user and the machine, A Basis operation step of receiving data from the human-machine interface work step and performing a translation of the program and interpolating the machine, A servo control operation step of receiving data from the Basis operation step and generating an actual motion trajectory, A position control operation step of receiving data from the servo control operation step and performing a position control and a work plan of the whole system, And a logic control operation step of receiving the input data from the machine and the input / output signal from the machine and operating the machine. 1. A method for dynamically configuring a numerical controller at boot-up using a script file for configuration defining an entire system, A script file reading step of reading a system script file at the same time that the numerical controller is activated, A hardware initialization step of initializing hardware by checking a system interrupt, a buffer memory and the like after reading out the script file, A task generating step of sequentially generating each position control task, a servo control task, a programmable logic control task, and a basis task after the hardware initialization step; An input / output script file reading step of reading an input / output script file after the task generation step; A routine table inserting step of loading execution modules and inserting routine tables after the input / output script file reading step, And a task execution step in which all the tasks are periodically executed if it is determined that the initialization process is successful and the initialization process is determined to be successful as a result of the determination. 3. The method of claim 2, Wherein the execution cycle of the task is arbitrarily controlled by the user. 3. The method of claim 2, And a numerical control routine is sequentially executed by using a routine table defined in the table to define a routine table defined by the module header defined in the table. Way.