An approach to integrating intelligentdiagnostics and supervision of machine tools

Arguments are presented for the necessity of integrating diagnostics and supervision in technological machines. An example of integrated diagnostics and supervision of the machine tool main drive, based on an expert system and neural network, is shown. Problems of intelligent thermal displacement supervision and questions related to practical supervision of machining centres are presented.     

Design of a discrete Kalman filter for a tactile sensor in a feedback control system

This paper presents a design methodology for the optimum linear filter and predictor applied to robot sensor signals, as well as a sensitivity analysis of the kalman algorithms for uncertainties in the estimation of signal and noise parameters. Simulation of the filtration and prediction processes was made assuming a first-order spectrum of a pure signal and white measurement noise. Calculations of the algorithm errors, dependent on the accuracy of the signal and noise parameter estimation, were done for various spectra of the signal and for various signal-to-noise ratios. Furthermore, the sensitivity curves of the Kalman filter and predictor are presented. The outlined considerations might be helpful for designers when synthesizing optimum linear digital filters applied to sensor signals. Although that particular procedure has been designed for a robot tactile sensor application, the conclusions are more general, and applications may be found elsewhere.     

The ‘linguistic pattern’ method for a workstation layout analysis

The ‘Linguistic Pattern’ approach to the facilities and panels layout is presented. This approach is based on Zadeh's possibility theory and the Lukasiewicz multivalued implication formula. The idea of the approach is presented on the basis of a simple exemplary problem of an automobile display arrangement. The general idea of a computer algorithm is presented and some potential benefits of the proposed approach are discussed.     

POLYOPTIMIZATION PROBLEM IN POWER CORE–TYPE TRANSFORMER DESIGN

ABSTRACT

The paper describes an optimum mass–efficiency design of power single–phase core–type air–blast oil Immersed transformer. The optimization problem is reduced to finding the minimum of the modifying scales function In a 6–dlmenslonal space bounded by 18 or 19 operation and design Inequality constraints based on Kuhlmann theory. To increase the efficiency of transformer modeling, it is used the first author's Idea of two–level hierarchic optimization modeling system. As an application example, an American existing transformer has been optimized. The polyoptimization problem has been solved for discrete net of scales factors. Based on a principle of maximum benefit, the polyoptimum–preferred design has been selected afterwards.     

ANALYSIS OF DISCONTINUOUS CONDUCTION IN A PWM DC CHOPPER DRIVE SYSTEM

ABSTRACT

This paper is concerned with the problem of analysis of quasi-steady and transient processes in a p.w.m. d.c. chopper drive system. An analitycal approach to the performance analysis of a d.c. separately excited motor fed from a chopper and operated in the region of discontinuous conduction is presented. The system equations are solved to obtain closed form solutions for motor current and speed, for quasi-steady as well as transient conditions. The solution for quasi-steady state condition corresponding to any set of operating conditions/voltage, chopper duty factor, load torque/ and mechanical characteristics of the drive are directly obtained.

Performance analysis of the system presented in this paper can be directly extended to a more complicated systems/for example, containing RLC input or output filter/.     

ISOLATION AND SOME PROPERTIES OF AN ACIDIC FRACTION OF POLYPHENOL OXIDASE FROM JERUSALEM ARTICHOKE(HELIANTHUS TUBEROSUS L.)

An acidic fraction of polyphenol oxidase (EC 1.14.18.1), representing the bulk activity, has been isolated from Jerusalem artichoke tubers by copper affinity chromatography, followed by DEAE-Sepharose ion-exchange chromatography. Isoelectric focusing analysis showed a cluster of activity bands (microheterogeneity) in the pH region of 4.5. The amino acid composition of the enzyme was also determined. The pH optimum for oxidation of chlorogenic acid, 4-methylcatechol and catechol was 6.0. Substrate inhibition was observed by high concentrations of chlorogenic acid. Thermal inactivation data indicated an apparent activation energy of 26.2 kcal/mol. Kinetics of inactivation, upon copper removal by KCN treatment, and reconstitution reactions revealed that the former is a much slower process than reactivation.     

Stability of linear systems with periodic feedback and sampled-data systems

A linear multivariable time-invariant system with three periodic state feedback strategies—dynamic, static, and of the instantaneous state—is considered. For each of these feedback strategies the stability question of an appropriate closed-loop system in relation to its dependence upon the repetition frequency is examined. The proposed approach to the question is based on exponential matrix representations of the dynamics of the considered closed-loop systems. It is shown that at sufficiently large values of the repetition frequency the stability question may be decided on the basis of the stability of a certain matrix which is common for all the considered feedback strategies. It is also shown that peculiar to discrete-time control, the dead-beat stability phenomenon may appear only for a dynamic or static feedback strategy and it may be achieved when the repetition frequency is small enough. The proposed approach results in some new characterization of the stability property for multivariable sampled-data systems.