Solid State Phenomena Vols. 147-149

Abstract: This paper present and validates experimentally a model-less methodology for off-line identification of modifications of nodal masses. The proposed approach is entirely based on experimentally measured data; hence no numerical modeling and tedious fine-tuning of the model are necessary. The influence of the added mass is modeled using virtual distortion forces and experimentally obtained system transfer matrices. The identification amounts to solving an optimization problem of minimizing the mean square distance between measured and modeled structural responses, the latter is based on previously recorded responses of the unaffected structure.

Abstract: The main causes of uncertainty in measurement regarding long-stroke line scales are line detection errors and external factors, especially temperature effects. The number of calibration errors of this sort increases with the extension of calibration time. Therefore, a dynamic method of line scale detection for modern long-stroke line scale comparators is used [1, 2, 3]. The article discusses the dynamic method of line scale detection by means of an optical microscope equipped with a photosensitive cell matrix and a line scale detection algorithm. Advantages of the dynamic method of scale calibration in terms of rate, accuracy and throughput are presented. The method’s error (detection parameters) correlations with detection rate, number of nominal lines, measuring rate, exposition delay are analyzed and mathematical models are described. The optimal values of these parameters are estimated. We are particularly interested in the improvement of the dynamic calibration program algorithm and minimization of uncertainty in measurement. The method was implemented and tested on the long-stroke line scale comparator, which has been developed and realized by JSC Precizika Metrology [3, 4, 5] in cooperation with VGTU and KUT.

Abstract: The methods of image processing for problems of detection and the analysis of movements and detection of concrete objects moving in video surveillance systems and other applications are considered. The field of speeds received by means of optical streams allows to analyze complex situations with which does not consult classical difference method, for example, the analysis of movement in crowd, or allocation of the person on strong disturbance images. The field of speeds is broken on cluster which allocate separate elements in complex area. For the detection on the personnel of objects is proposed the method, based on the theory of the ideas of continuous groups, which makes it possible to carry out a Fourier analysis relative to special functions, in the best way fitted out for the specific transformation groups, for example, group of the motions of plane. The analogs of the theorem about the roll and of the properties of Fourier transform make it possible instead of the labor-consuming correlation method to manage with the calculation of the pair of integrals.

Abstract: In the paper the procedure of processing biomechanical data has been proposed. It consists of selecting proper noiseless data, preprocessing data by means of model’s identification and Kernel Principal Component Analysis and next classification using decision tree. The obtained results of classification into groups (normal and two selected pathology of gait: Spina Bifida and Cerebral Palsy) were very good.

Abstract: This paper deal with possibility of cochlea function principle utilization for decomposition any non-stationary signals. The mathematical model based on array of resonators is described in this paper. This array of resonators is actuated by non-stationary signal, which is compound from different frequency components. Spectrograms calculated for different values of resonators viscous damping are results of this work and this results are also compared with spectrogram obtained from Short Time Fourier Transformation (STFT).

Abstract: Human gait analysis and classification is the process of identifying individuals by their walking manners. Computerized gait analysis using neural networks and fuzzy logic has become an integral part of the treatment decision-making process. Authors proposed the integration of kinetic data, more specifically power joints in combination with neural networks and fuzzy logic. It is a relatively new addition to other types of data including temporal and stride parameters. The performance of our approach was verified in laboratory for motion analysis. The obtained results are satisfying.

Abstract: The paper presents the use of the autocorrelation function for the description of vibrations and the problems connected with. The proposed method is based on the analysis of vibration signal recorded for machine during its operations using an analytic form of the autocorrelation function. The parameters are obtained using a curve fitting procedure. To keep a quality of parametric representation of considered vibration, only the curve fitting causes a determination coefficient over 0.90 is taken into consideration. Therefore, the autocorrelation functions are submitted for the fast Fourier transform to be helped, in determination of number of the dominant harmonic components. Also, the analytic form and parameters of power spectral density has been also calculated. Finally, the set of parameters has been collected to describe the selected fragment of vibration of the simple rotating machine. The influence of duration of analyzed vibration on the parameters values is also examined in this work.

Abstract: The objective of this paper is to identify the parameters of a new plane biodynamic model of a man jumping down on a hard base. In the modelling of this kind of dynamic phenomena, with dominant directions of human body motion and reactions, many simple and complex models have already been applied. Some of them were lumped parameter and unidirectional [Książek, 1999], [Fritz, 2001] or plane [Pandy, 1990], [Farley, 1998]. There are also spatial models, applied in the sport and medical investigations of the kinematics and dynamics of the human body [Morecki, 1990], [A. Nagano and col., 2005]. The presented approach has been founded on the results of experiments described in [Nosiadek, 2006] where body motions of 40 men volunteers were registered during drop jumping and landing from several assumed heights. By means of video cameras in 3D space and a dynamic platform linear and angular displacements of participants’ bodies and three mutually perpendicular components of the dynamical reactions between the feet and platform were measured. The numerical results of the displacements were numerically remodelled by the authors of the present paper and used for synthesis of models of muscles of a man during drop landing. Similar investigations can be found in [Pain and Challis, 2006].

Abstract: A new approach for solving sinusoid extraction problem in presence of distortions is proposed. Formulation of considered problem contains assumptions that sinusoidal signal is single and pulses are strictly finite in the time, but parameters of sinusoid as well as locations, durations and amplitudes of pulses are unknown a priori. We show that standard least squares criterion, based on the minimization of approximation error square, is inapplicable for parameter determination problem in presence of distorting pulses. The criterion of the minimum of the "duration" of approximation error is used to effectively solve the considered problem. Results of numerical simulations of the proposed method are presented. Developed approach is applied afterwards for the problem of restoration of distorted vibration data signal, collected by microwave measurement facility.

Abstract: Vibration measurement of CNC milling is one of the used techniques for prediction of tool wear. Monitoring of tool wear is very important since a worn tool will affect machine and workpiece either. We developed a fiber-optic sensor for spindle vibration of CNC face-milling machine. The sensor is based on monitoring loss of light from the fiber core. For this sensor a laser light transmitter circuit, a sense plane construction, and a light receiver circuit are designed. Designed fiber-optic sensor is tested on Taksan TMC 650V face-milling machine. Obtained signals from this sensor is investigated in time domain and frequency domain and showed that it is valuable to tool ware monitoring.