Volume 61 (2010): Issue 2 (March 2010)

This paper describes a method for slosh-free moving of containers with a liquid at which the conveyor belt is flexible. It shows, by means of experimental results, that a container filled with a liquid can be regarded as a damped pendulum. Upon parameter identification of the two single-mode subsystems, theoretical modelling of the complete system is described. With respect to industrial application, feedforward control is used to transfer the container in horizontal direction without sloshing. The applied method requires deterministic and hard real time communication between the PLC and the servo amplifier which is realized here with Ethernet POWERLINK. The principle structure, calculations, time duration and the robustness of the basic types of input shaper are described and compared with each other. Additionally the positioning results of the two-mode system are presented. Finally, a possibility of the principle software implementation is presented.

In this paper an efficient method for optimal overcurrent relay coordination is proposed. In the proposed method using genetic algorithm, an objective function (OF) is developed to solve the problem of miscoordination for six pairs short circuit fault currents. The new OF is improved to be simple, optimal and efficient. This technique takes into account the changes in network configuration. The efficiency of the proposed technique is demonstrated by comparing the results of two different networks namely typical 8-bus & IEEE 30-bus systems with those obtained using the recently developed techniques.

An optical ring network employing optical packet switching is investigated. An analytical approach allowing the computation of end-to-end cell loss ratio (CLR) is proposed. The CLR dependence on topological parameters (number of stations), network parameters (number of wavelengths), and node structure (buffer capacity) is computed assuming a uniform traffic load. A discrete event simulation confirms the analytical results.

This paper presents a novel method to enhance the performance of Independent Component Analysis (ICA) of myoelectric signal by decomposing the signal into components originating from different muscles. First, we use Multi run ICA (MICA) algorithm to separate the muscle activities. Pattern classification of the separated signal is performed in the second step with a back propagation neural network. The focus of this work is to establish a simple, yet robust system that can be used to identify subtle complex hand actions and gestures for control of prosthesis and other computer assisted devices. Testing was conducted using several single shot experiments conducted with five subjects. The results indicate that the system is able to classify four different wrist actions with near 100% accuracy.

Faults in an industrial process could be timely detected and diagnosed in many cases. It is possible to subsequently reconfigure the control system so that it can safely continue its operation (possibly with degraded performance) until the time comes when it can be switched off for maintenance. In order to minimize the chances for drastic events such as a complete failure, safety-critical systems must possess the properties of increased reliability and safety. Faults in robotic systems are inevitable. They have diverse characteristics, magnitudes and origins, from the familiar viscous friction to Coulomb/Sticktion friction, and from structural vibrations. This paper presents an on-line environmental fault detection, isolation and an accommodation scheme.

Optimal finger placement improves significantly the performance of RAKE receivers. However, due to its high complexity, it is rarely applied in mobile systems with large channel spread. In this paper, we evaluate the merits of suboptimal finger allocation in terms of performance and complexity. A subset of the RAKE fingers is optimally positioned based on the received signal correlation properties while the rest of them are uniformly distributed within the channel spread. The tradeoffs between performance and complexity of the method are discussed. Results show that optimizing half finger positions lead to similar performance with the full optimization scheme. Finally, comparisons with conventional and optimal receivers exhibit the advantages of the method.

The paper addresses the problem of an output feedback guaranteed cost controller design for Networked Control Systems (NCSs) with time-delay and polytopic uncertainties. By constructing a new parameter-dependent Lyapunov functional and applying the free-weighting matrices technique, the parameter-dependent, delay-dependent design method will be obtained to synthesize PID controllers achieving a guaranteed cost such that the NCSs can be stabilized for all admissible uncertainties and time-delays. Finally, numerical examples are given to illustrate the effectiveness of the proposed method.

Artificial neural networks (ANN) in general classify patterns according to their relationship, they are responding to related patterns with a similar output. Polynomial neural networks (PNN) are capable of organizing themselves in response to some features (relations) of the data. Polynomial neural network for dependence of variables identification (D-PNN) describes a functional dependence of input variables (not entire patterns). It approximates a hyper-surface of this function with multi-parametric particular polynomials forming its functional output as a generalization of input patterns. This new type of neural network is based on GMDH polynomial neural network and was designed by author. D-PNN operates in a way closer to the brain learning as the ANN does. The ANN is in principle a simplified form of the PNN, where the combinations of input variables are missing.

In this paper the propagation of electrical treeing in nanodielectrics using the DIMET (Dielectric Inhomogeneity Model for Electrical Treeing) is studied. The DIMET is a model which simulates the growth of electrical treeing based on theory of Cellular Automata. Epoxy/glass nanocomposites are used as samples between a needle-plane electrode arrangement. The diameter of nanofillers is 100 nm. The electric treeing, which starts from the needle electrode, is examined. The treeing growth seems to be stopped by the nanofillers. The latter act as elementary barriers to the treeing propagation.