Adam Woźniak

Using the second-order information in pareto-set computations of a multi-criteria problem

The paper presents an extension of a previously developed interval method for solving multi-criteria problems [13]. The idea is to use second order information (i.e., Hesse matrices of criteria and constraints) in a way analogous to global optimization (see e.g. [6], [9]). Preliminary numerical results are presented and parallelization of the algorithm is considered.

An interval method for seeking the Nash equilibria of non-cooperative games

Computing Nash equilibria in continuous games is a difficult problem. In contrast to discrete games, algorithms developed for continues ones are rather inefficient. This paper proposes a new approach - making use of interval methods we try to solve the problem directly, seeking points that fulfill Nash conditions. We also consider a shared-memory parallelization of the proposed algorithm. Preliminary numerical results are presented. Some new practical aspects of interval methods are considered.

Systematic errors of measurements on a measuring arm equipped with a laser scanner on the results of optical measurements

Laser triangulation is an optical measuring method which characterizes with relatively high precision. There are many factors which can affect this type of measurement. They depend on a nature of optical measurements. Equally important from the viewpoint of accuracy is how precisely the position of the scanner in measuring volume is determined. In this paper we present tests performed using measuring arm equipped with a laser scanner. As in measuring arms position of the probe depends on the accuracy of angular encoders their influence on the results was tested. Five different strategies were chosen to show the significance of employment of additional encoders. Results showed that if less encoders are used, better results are obtained. Also overlapping of individual scans affects precision of results. Therefore one should pay attention on choosing proper measuring strategy, to not change the scanning direction excessively and to not scan the same area many times.

Methods for verifying the dimensional and material properties on industrial CT scanners according to VDI / VDE 2630 Blatt 1.3.

In the article methods for verifying the dimensional and material properties like GS, GF i GG on industrial CT scanners according to VDI/VDE 2630 Blatt 1.3. “Computertomografie in der dimensionellen Messtechnik” guidelines were described. The proposed gauges in the form of a stepped cylinder were presented. In studies two types of different materials of gauges with different X-ray absorption coefficients were used. The study on METROTOM CT 800 manufactured by C. Zeiss with the X-ray tube voltage of 130 kV was performed. As the material for the gauges aluminum (aluminum alloy PA6) and ertacetal was selected. Both gauges in an accredited laboratory were calibrated.

Applying an interval method for a four agent economy analysis

This paper presents an application of interval methods for simulation of a policy game played by four main agents of economy: profit maximizing companies active on competitive market, the monopolistic trade union (aggregated wage setters), the government and the central bank. After reduction of companies as an active agent, the resulting three agents decision system is modeled as a Stackelberg game with the central bank as the leader and trade union and government as composite followers, aggregated by means of the Nash solution. The simulation of policy game is provided. A previously developed interval method is applied to find Nash points rigorously.

Policy Modeling in Four Agent Economy

This paper proposes a simple model of policy game played by four main agents of economy: profit maximizing firms active on competitive market, monopolistic trade union (aggregated wage setters), government and central bank. The interactions between agents are described by the single period aggregate demand and supply equations. We also adopt assumption of bounded rationality of agents. After reduction of firms as active agent, the resulting three agents decision system is modeled as Stackelberg game with central bank as leader and trade union and government as composite follower, aggregated by means of Nash bargaining solution. The simulation of policy game is provided.

Influence of Measurement Parameters Settings on the Results of the CT Measurement

Nowadays X-ray computed tomography for industrial applications is most frequently used for defectoscopy analysis or nondestructive testing. However, it is increasingly used for geometric measurements. The accuracy of geometric measurements is influenced by many factors such as: measurement parameters (X-ray tube and detector settings), environmental conditions, reconstruction algorithms, element alignment, threshold value etc. The article presents the influence of setting parameters of the X-ray tube (voltage and current) and detector (integration time and gain) on the results of geometric measurements. Studies were performed using Carl Zeiss computer tomograph METROTOM 800. Ceramic balls (Si3N4) of G5 accuracy class were selected as the reference master artifacts.

Master artifacts for testing the performance of probes for CNC machine tools

Methods of testing the performance of probes for CNC machine tools, the same as methods of testing the performance of probes for coordinate measuring machines (CMMs) can be divided into indirect methods and direct methods. Indirect methods give information about performance of the whole on-machine measuring system, including the probe and the machine tool. Direct methods enable separation of the probe’s errors and the machine tool’s errors, but they need an additional equipment. One of the direct methods of probe testing is a method with moving master artifacts. Performance of this method depends on the master artifact used. In the paper various master artifacts are presented, as far as results of probe testing with use of them.

Mechatronics in monitoring, simulation and diagnostics of industrial and biological processes

The paper describes a number of research projects of the Faculty of Mechatronics of Warsaw University of Technology in order to illustrate the use of common mechatronics and optomechatronics approach in solving multidisciplinary technical problems. Projects on sensors development, measurement and industrial control systems, multimodal data capture and advance systems for monitoring and diagnostics of industrial processes are presented and discussed.

A simple model of drive with friction for control system simulation

This paper proposes a simple discrete model of drive with friction. The nonlinear part of the model is based on the observation that friction is maximum just before two objects begin to move, and de creases when the objects are in motion with constant relative velocity. Although it falls in the realm of classical Static+Coulomb+Viscous models of friction it is a dynamical one. Linear part is based on the typi cal linearized equations of a DC motor. The obtained model equations can be easily modeled, e.g., in SIMUUNK. The complete model has four pa rameters and simple identification procedure is presented. An example of model parameter identification is provided.