PCNC research and development laboratory

Synopsis to our publications

Analysis of control systems

V. L. Sosonkin, G. M. Martinov
The analysis of the contemporary world level of the NC-systemís architecture

There is submitted and illustrated the analysis of different architectural versions of NC systems. The suggested classification points out to five different architectural platforms, which co-exist at the market. In the spectrum of architectural versions, the PCNC concept occupies the strongest positions. The most significant tendency consists in advancing and realizing ideas of the NC open architecture, which provides to the end user broad possibilities to integrate their own functions into NC systems.


V. L. Sosonkin, G. M. Martinov
The integration, based on the open control and the OPC standard (OLE for Process Control)

Preliminary the interface OPC standard was implemented for the universal connection of different logic devices, data sources and field busses together with client applications. The success and large spreading of the standard explain the fact that in its sphere there have been involved NC systems, SCADA systems and terminals of the integrated technological medium. Inasmuch as the OPC standard appeared to be in the area of interests of NC developers, further there are discussed some problems of open control; these problems are connected with applying the OPC standard.


V.L. Sosonkin, G.M. Martinov
The integration based on the complex of industrial standards STEP (Standard for the Exchange of Product model data)

The STEP standard is used to create the information model of some product, this model is working at all stages of the product life cycle, at that. The stage of transition from the CAM automatic programming system to the NC system itself is called STEP-NC. After the final international coordination of this stage, there are expected both the cardinally more perfect system of NC programming and substantial changes in the NC architecture proper. This paper is devoted just to the analysis of this problem.


The architecture of NC mechatronic systems

V. L. Sosonkin, G. M. Martinov
The architecture of PCNC systems

There are discussed main symptoms of a new generation of NC systems, which are: belonging to the class of PCNC personal control systems; using principles of the open architecture. There are pointed out advantages of both "one-computer" and "two-computers" control systems: flexibility, the client-server organization of transactions and the object-oriented approach at the level of macro-structure and at the level of programming technology. There is submitted a new organization of NC systems, where modules with traditional names have new functional and algorithmic filling and new software realization. A special role of the PC-subsystem is highlighted, which defines user characteristics and the level of service for an operator.


G. M. Martinov, V. L. Sosonkin
The problem of real time

It is shown, that NC systems have both, - modules, working in the machine time, and modules, working in the real time. All application modules communicate between themselves and require dispatching. Dispatching problems are near to those, which could be solved by means of the real time operating systems. Here, the task is to find the way to organize the work of all control-system modules together as a whole. For this purpose it is necessary to find an adequate solution for the real-time problem and to build on this basis a dispatcher of application programs. In this connection there are observed existing suggestions for standard and original real-time operating systems. There is proposed a concept of using real-time extension of the Windows NT operating system in control systems.


V. L. Sosonkin, G. M. Martinov
The organization of the inter-module communication medium

There is suggested an approach to build the inter-module communication medium of NC systems, when the communication medium takes for itself both the problem of integrating all modules of the control system and the problem of inter-module communication. The "component" COM-approach and well-known principles of the system integration are used as to develop separate modules of the NC system, as at the level of NC system macro-implementation. It means, that the problem of inter-module communication could be solved in the same way, as the problem of the system integration. The component COM-approach supports the distributed work, when NC modules might function in different threads and in different systems and be COM-servers and COM-clients.


G. M. Martinov, V. L. Sosonkin
Principles of developing remote NC terminals

There exist situations, when distributed NC systems provide additional conveniences; but also, there exist situations, when it is impossible to treat without it. In both cases there should be used the remote (from the NC kernel) terminal, which either duplicates the main NC terminal or substitutes it. The peculiarity of the remote terminal is, that it could use the diverse platform. Another peculiarity is, that its visual facilities are rather laconic. At that, there should be provided the access to the main kernel functions either through the local net or through the Intranet, or Internet may be. The target of the paper is to observe principles of developing remote terminals, which are rather new components of control systems.


Tasks of control systems

G. M. Martinov, V. L. Sosonkin
The realization of the geometric task

There is observed the NC geometric task with its main components, the interpreter of flow programs and the interpolator. It is shown the evolution of requirements to these modules during the last time: the interpreter should be adjustable to any version of the ISO-7bit code of flow programs; the interpolator should have the open (extensible) architecture and should avail any combination of interpolation algorithms. There is submitted an approach for realization of geometric-task modules in practice.


V. L. Sosonkin, G. M. Martinov
The realization of the logical control task

There is suggested a new approach to realize the logical task in the numerical control systems. Inside the life cycle of the logical task there are observed phases of programming, program interpreting and executing. At the first phase it seems to be interesting to use visual programming facilities, which deliver to the operator a convenient tool for the graphical dialogue implementation of cycle logic programs; these programs could be interpreted directly into C++ codes without intermediate compiling. The structure of the cycle logic software system could be substantially changed and made more effective, at that.


G. M. Martinov, V. L. Sosonkin
The realization of the terminal task

There are suggested formal methods and the original software tool for the realization of the terminal task skeleton in the Windows interface. There are implemented two configurable applications for editing, debugging and simulating flow programs; one application for the ISO-7bit code and another for the high-level flow program language. These applications could be either included into the terminal task or used independently in the personal computer.


V. L. Sosonkin, G. M. Martinov
The realization of the diagnostic task

Modern Numerical Control systems have enough free resources of computing power, which undoubtedly must be effectively used. The most preferable way to use it is to create and advance the diagnostic subsystem, which is rather weakly submitted in existing NC systems. In the first turn, there should be diagnosed the logical and geometrical control tasks. Here, there is suggested the concept of virtual devices, realized like ActiveX elements; this concept makes it possible to use developed diagnostic facilities in different applications, in which end users are mostly interested. Peculiarities of the further used COM-approach and COM-technology are such, that implemented diagnostic systems could be used in any Numerical Control systems.


V. L. Sosonkin, G. M. Martinov
Problems of the cycle-logic control

There are observed different versions of cycle-logic control in mechatronic systems with the help of programmable controllers. There is accentuated the increasing attractiveness of software (virtual) controllers, which are called SoftPLC. There is discussed the general organization of SoftPLC control: the system of notions in accordance with the IEC 6133-3 standard; the alternative structures of the client part of the control system project; the work of the server part of the control software; the object oriented approach for cycle-logic control; the peculiarities of cycle-logic control for NC machine-tools. There are accentuated two peculiarities of cycle-logic control for NC machine-tools: SoftPLC tasks are quasi-concurrent with NC tasks and work in the same operating system with them; control cycles are initiated in the NC flow program.


V. L. Sosonkin, G. M. Martinov, M. M. Perepelkina
Cycle logic control of NC machine tools by means of SoftPLC virtual controllers.

At the latest stage of PLCes evolution, there has appeared and obtained well-earned popularity the idea of their software realization (SoftPLC). This idea is mostly effective for Numerical Control systems, where SoftPLC software works in the same operating system environment as NC software. In this connection, there exists a necessity to build well-organized and observable software of the virtual controller, based on the object-oriented approach. Further, there will be discussed those problems of implementing the virtual controller kernel, which have not found their reflection in the available literature.


New technologies of developing NC software

G. M. Martinov, V. L. Sosonkin
The technology of the object-oriented programming

Up to the date, the traditional software of NC systems in the most cases uses the technology of the procedural programming, which could be considered a deadlock in this concrete application area. Nowadays, there come technologies of the object-oriented and component programming. In this connection, especially for control systems, there are proposed basic notions of the object-oriented approach; there are submitted methodical directions to choose objects in control systems; there are analyzed problems of creating object-oriented models on the base of the G.Bouch formalism. There are also touched problems of repeat using already implemented codes; there is demonstrated the possibility to support the object-oriented programming with software tools.

V. L. Sosonkin, G. M. Martinov
Specifics of the object-oriented programming

The technology of the object-oriented programming provides some standard approach to implementing software, but it does not take into consideration peculiarities of concrete realizations, for example, peculiarities of NC software. In order to reveal specifics of NC object-oriented programming, there are suggested: the abstract model of the PCNC system; the object-oriented model of the generalized PCNC module; the object-oriented model of data presentation. The set of such models makes it possible to observe key phases of NC software development; which are: the analysis, the implementation and the realization. The object-oriented model of the PCNC system makes the PCNC architecture and its software well structural and more transparent. Consequently, the software reliability becomes much better and the implementation process becomes more regular. On this basis, there appear prerequisites of creating the implementation environment. Elements of basic abstractions, classes of their object realizations, mechanisms on the base of such classes, - all these serve to create higher level blocks of NC systems. The examples of such blocks are channels, axes tied to channels, etc.


G. M. Martinov, V. L. Sosonkin
Methodological aspects of open NC systems

Openness of NC systems, of the PCNC type, - should be passed to hands of end users, who are exploiting NC systems. One possibility is to build NC modules like open language processors, which combination defines the regular architecture and the configurable set of commands. Open language processors, in their turn, must be implemented on the base of the object-oriented approach, which solves the problem of compatibility. Some problems of implementing PCNC open systems could be overcome with the help of Windows NT system abilities. At that, there appears a possibility to use ready-made applications and the accumulated experience, to reduce expenses for development, to increase the whole system reliability. Standard software tools should also be used to support the open architecture, - they create the mighty subgroup in the environment of the PCNC-system development. However, they are not enough; that is why it is necessary to have own software tools for well-formalized tasks. When creating the development environment, there appears a possibility to suggest a global solution of problems, connected with the process of open-NC-system implementation. Concrete solutions are tied with certain stages of the implementation process in such a way, that the whole iterative implementation process becomes regular.


G. M. Martinov, V. L. Sosonkin
The technology of the component organization of software

There is suggested the component organization of control-systemsí software. There are submitted basic notions and methodical recommendations, which help to choose components. There are discussed complicated cases of creating component models in control systems, particularly on the base of standard libraries, MFC and ATL. There is found the preferable area of the COM approach in control systems. There is accentuated the possibility to use G. Bouch software tools in order to support the component development.

Documents of the NC systemsí user

G. M. Martinov, V. L. Sosonkin
The structure of the programming-NC-systems manual

The contents of the document, the programming-NC-system manual, contain: descriptions of the phase space of the technological machine, descriptions of the ISO-7bit code version (which main principles are submitted in standards, DIN66025 and ISO6983), directions concerned with possibilities to raise the language level of the ISO-7bit code, comment to the usage of preparatory G-functions. The ISO-7bit code has not lost its significance up to the date, and it is advancing constantly by means of adding new preparatory functions. The set of such functions is a good reflection of user abilities of the control system. Some time ago, the classical range of G-functions was no more than 100, and different versions of the ISO-7bit code differed one from another not so much. But now, this range is approaching to 1000. In this connection, there are observed some important peculiarities of expanded versions of the ISO-7bit code, which are usually omitted in superficial descriptions.


V. L. Sosonkin, G. M. Martinov
The configuration of NC systems

Normally, NC-systemsí OEMs produce some basic model, which is gradually evolving; but the substitution of basic models is made comparatively rarely. The market success of the model depends upon its ability to be adapted to endlessly diverse requirements of machine-tool builders and end users. The adaptation ability is defined by the set of configuration parameters. As a matter of fact, configuration parameters are global variables of the NC system. Values of parameters must be set at the stage of adjustment between the technological equipment and the NC system; and after this the access to editable parameters is available only for persons with special access rights. The programmer-technologist (who is the member of the end-user group) is able to temporally change values of some parameters inside the flow program by means of specially oriented preparatory G-functions. The problem of choosing configuration parameters (which are often called machine parameters) is not described in the available literature. In this connection there has been undertaken an attempt to make a certain summarizing.

Advanced direction

V. L. Sosonkin, G. M. Martinov
State of the art in numerical control system architectures: analysis

The paper analyses and illustrates numeric control system architecture. It offers a classification that shows the availability of 5 system architectures and proves that the PCNC concept has the strongest position in the market. The most important trend is the development and implementation of open NC architecture concepts that enable wide opportunities for end users to introduce their own functions in the NC system. The trend to incorporate NC systems into STEP environment is also discussed. This trend leads both to new NC programming systems and to novel architectures.

V. L. Sosonkin, G. M. Martinov
Latest trends in numerical control system architectures

Numerical control system architectures available in the market were analyzed in [1]. Further study showed that PC-based variants are the quickest to evolve. Special attention is paid to the development of open systems, SoftCNC or Motion Control open numerical control kernel, systems with STEP-NC interface including the intelligent ones, and web-enabled systems. All these are the objects for further investigation.