Jaaghi Halil INTERACTIVE SYSTEM OF THE ANALYSIS OF OPERATIONAL EFFICIENCY OF INDUSTRIAL AND ECONOMIC SYSTEMS
The proposed interactive system consists of a number of mutually interconnected stages, brief content of which is discussed below.
At the first stage, analysis of an enterprise’s activity is carried on the basis of its accounting and planning data. In this regard, traditional models of managerial or administrative analysis are utilized which allow to determine the ‘painful’ points of the enterprise’s current activity. However, this analysis is not directed at the exposure and evaluation of not only the obvious factors but also development factors of industrial and management systems that are hidden from direct observation, and determination of the most preferable factors for further development.
At the second stage, models of factors are used for determining the development strategy of industrial and economic systems. In the realization of these models, it is sufficiently difficult to put together a sample of large dimensionality in order to fully reflect the characteristics of the aggregate. Therefore, in the given system the approach of space-time aggregate is used, based on models of automatic classification. Direct association of samples by different enterprises often lead to a situation where the common selective aggregate does not satisfy the minimum requirement of homogeneity. Hence, the suggested approach with the help of methods of automatic classification would lead to an a priori partition of all data set into separate groups ( classes, clusters, etc. ) to the limit of each to ensure homogeneity of the economic situation, and consequently a more stable development of its characterizing factors. By the construction of models, it would allow the forecasting to sustain basic conditions: preservation of static structure of the object. The use of the factor analysis allows to give formalized approach to the selection of technical and organizational factors and, indeed, to avoid dependence on the structure of competence of expert groups in an expert inquiry. There is no necessity to operate with a bulky set of individual estimated indices. The derived factor model is aimed at research of the development dynamics of the system as well as the determination of priority paths of its development.
At the third stage, a set of models for forecasting technical and economic indices is proposed. This considers the derived system of forecast values of indices considered as probable state of the system by preservation of existing development tendencies of the technical and organizational factors. The significance of that or another factor and the development direction of industrial and economic systems is determined by the magnitude of deviation of the planned value of an index from the forecast value and also by the degree of influence of a given factor on a corresponding index. A model of automatic selection (of a sample) has been realized. It is of a kind of predicting function by the criterion of maximum explained by the variance of minimum of average quadratic error. Under the circumstances, the data of an enterprise or any selected class would serve as the initial data for models.
At the fourth stage, a retrospective analysis of the system development is carried out. This is necessary not only in the arising of tangible operational failures of the system but also for the exposure of its hidden and imminent development tendencies. During analysis, factors - which are given preference in the course of preceding operation of the system - are determined and how all this is reflected on the eventual results of the systems’ activity. As an auxiliary instrument for the person taking decision, we can use the model of administrative analysis, which was applied at the first stage. If it is necessary to carry out a detailed analysis by somewhat separate subsystem, then a repeated iteration should be conducted. In this case, the subsystem is considered as the object of research and the enterprise as a whole as an external medium.
At the fifth stage, we can use a set of models by estimation of the formal organization of the control system, which is analyzable by the industrial and economic organization. By the results of analysis, it is possible in terms of value to estimate how much it would have cost each industrial subdivision, provided control systems are employed within the organization. Besides that, at this stage based on a model of analysis of information flow circulating within the enterprise, it is possible to evaluate how many effectively organized ares the processes in the very control system.
In conclusion, it should be noted that the use of all afore-mentioned models is not only possible in set, but also independently depending on the objectives and targets of an undertaken research.
Y.Veryha EXPERT SYSTEM FOR REDUNDANT ROBOTIC MANIPULATORS
Many of the stages of the technical system design cannot be fully formalized or must be solved with the incomplete information available. Thus, a need arises to develop a program that can operate with expert knowledge (heuristics). General-purpose expert system, easily adjusted for the specific purposes, has been used in the area of the redundant robotic manipulator motion optimization. The expert system works in two modes: knowledge obtaining (expert's development) and consultation (operation by users).
One of the main problems that must be solved in the robotic manipulator control is the inverse kinematic and dynamic problems, that consist in finding the joint motion for the given end-effector motion and accordingly joint forces and torques for the given end-effector force. For the redundant robotic manipulators, there is an infinite number of solutions to the inverse kinematic and dynamic problems.
The redundant robotic manipulator admits an infinite choice of the inverse kinematic solutions so that they are available for the optimization of different performance measures, corresponding to various task requirements, for instance, minimum-energy, minimum-effort, minimum-torque, minimum peak-torque, etc. Depending on the task requirement to the given redundant robotic manipulator, there exist methods using the Euclidian norms of vectors in the joint space, but there is no general method that could be used for all of the above-mentioned criterions of the optimization. It means that only local methods, for example, method of the peak torque reduction, etc., can be used in practice and have their real industrial application.
It has been proposed to use the consequent optimization based on the method of the expert evaluations that allows preliminary computer-aided ranging (with the help of the developed expert system) of the optimization criterions. This method allows to perform preliminary criterions ranging on the base of their importance in the given industrial application for the given redundant robotic manipulator. The experts use various data of the manipulator hardware and software for forming their evaluations: type of joint actuators (characteristics, maximum torque, energy consumption, etc.), type of joints (hardness, backlashes, wearness, etc.), requirements to the quickness and accuracy from the technological operations, etc.
All these characteristics are evaluated by experts with the help of the developed expert system. The expert system includes the knowledge base, the criterions group and the computational unit. The computational unit on the base of the expert evaluations performs criterions ranging. Such an approach to the optimization problem of the redundant manipulator dynamics and kinematics allows the consequent use of the previously developed local optimization methods using them one after another depending on the result of their ranging in the expert system. The expert system forms the criterion queue for the redundant manipulator optimization (for example, minimum-energy, minimum-torque, etc.) for the future use of them in the following way. The criterion that follows after another in the queue just corrects the preliminary parameters of the robotic manipulator dynamics and kinematics, obtained in the previous local optimization by the given criterion. After this procedure, the optimization solution for the given redundant manipulator dynamics and kinematics can be formed.
The developed expert system is intended for a computer-aided selection of a preferable solutions from a number of the the alternatives. It is based on the well-known method of the expert evaluations. It is a general-purpose method which is particularly recommended for the decision-making with regard to the versions that have numerous contradictory criterions that are difficult to be expressed qualitatively by the qualified specialist-experts. The expert system is developed in the Visual Basic 5.0 and DBCS Access 7.0 and operates in the Windows environment.