Saulius Kausinis

Line Scale Calibration in Non-Ideal Measurement Situation

The precision line scale calibration in dynamical mode of operation is considered. A new interferometer-controlled comparator with moving microscope has been developed and optimised in order to reduce both the measurement uncertainty and calibration process duration. Modal analysis performed and measurements conducted of the spatial vibrations of comparator structure revealed that dynamically-induced errors can noticeably contribute to the measurement uncertainty budget. They can be prominently reduced, in particular, by proper improvement and optimisation of the carriage structure and elimination of the dry friction in the carriage drive.

Software based control techniques for precision line scale calibration

A precision line scale calibration method in a dynamic regime enables to gain the calibration throughput and simplify the comparatorpsila s structure and control. However, the errors featured by geometrical deviations, static and dynamic loads as well as temperature induced deformations should be considered and incorporated into uncertainty budget. These errors contain random and systematic components and can be minimized by increasing the accuracy of system design and implementing numerical error compensation methods. The paper discusses advances of precision line scale calibration system design gained by implementing new measurement and software based control techniques.

Estimation of thermo-elastic damping of vibrations in micro-electro-mechanical systems resonators: finite element modeling

Abstract. The authors investigated finite element (FE) analysis of damped modal vibrations in complex geometries of micro-electromechanical (MEM) resonators. Q-factor values were determined by taking the thermo-elastic damping into account. The basic model created is presented as a system of partial differential equations, which describe the elastic and thermal phenomena in the MEM structure. Mathematically the problem is formulated as a complex eigenvalue problem. Modal properties of square- and ring-shaped bulk-mode MEM resonators were investigated by taking into account the layered structure of the MEM system and the influence of the geometry of the clamping zone. The calculations were performed by employing the COMSOL Multiphysics FE software. The solution method was verified by comparing numerically and analytically obtained damped modal properties of a MEM cantilever resonator.

Simultaneous measurements of dynamic values using the transit time method

The problem of simultaneous and accurate measurements of two dynamic values, time dependencies of flow velocity and ultrasound velocity in the flow, is analyzed. In order to measure two dynamic values simultaneously a theory of the transit time method has developed, and the theoretical model of a microprocessor-based measuring system has been derived. The ways to improve the accuracy and information of such dual-channel measurement systems have been examined. It is shown that invariance between two channels of a measurement system can be achieved when dynamic, nonlinear, parametric models of these channels are identified in real time during the process of measurement, and when the multipulse irradiation of flow is used. The results of computer simulation of transit time method dynamic errors are represented. A method of minimizing these errors has been proposed. >

Finite element modelling and simulation of thermo-elastical damping of MEMS vibrations

The contribution is directed to providing accurate simulation and approximation of the Q-factor determined by thermalelastic damping in complex micro-electromechanical (MEM) resonators. The base model created is presented as a system of partial differential equations, which describe the elastic and thermal phenomena in the MEM structure. The FEM calculations were performed by using COMSOL Multiphysics software. The model was verified by comparing numerically and analytically obtained damped modal properties of a MEM cantilever resonator. The comparison of calculated and experimentally obtained resonant frequencies and Q-factor values indicated a good agreement of tendencies of change of the quantities against temperature. Investigation of longitudinal and bending vibration modes in 3D of a beam resonators was accomplished by taking into account the layered structure of the resonator and the influence of the geometry of the clamping zone. Modal properties of rectangle- and ring-shaped bulk-mode MEM resonators were examined, too.

Analysis of Dynamic Method of Line Scales Detection

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.

Dynamic Mode of Line Scale Calibration

The need for high-resolution and high-speed detection of line scale graduations is a result of increasing throughput requirements of precision scale calibration systems. These new demanding requirements can be met by exploiting the advantages of the dynamic mode of calibration. The state-of-the-art platform-based approach to improving calibration systems performance will allow both functional extension to already deployed systems and the design of new ones, capable of adapting to different application patterns and user profiles. An interferometer-controlled comparator setup has been designed to measure the performance of the dynamic calibration process. A novel 3D finite element model has been developed in order to both investigate thermo-mechanical processes in the comparator structure and evaluate possible temperature influence on geometrical dimensions of the line scale. A series of measurements has been conducted at PTB and MIKES length calibration laboratories in order to evaluate the capabilities of the dynamic calibration of graduated line scales.

Length Metrology and Calibration Systems

Accurate length measurement plays a vital role in meeting the needs of industry and commerce for traceability to common national and international standards, especially in view of the common market and world trade. Such measurement needs arise across a wide applications base, from large-scale engineering projects such as dam construction, aerospace and shipbuilding, through automotive engineering and components manufacture, to precision engineering and nanotechnology (DTI/NMDS, 2002b).

Parametric Sensitivity of MEMS-Gyro

The paper presents the finite element (FE) modeling approach to sensitivity analysis of MEMS-based gyros. The FE model is employed to both studying the system’s dynamical properties and appreciation of the sensitivity of these to various influencing effects. The sensitivity functions have been obtained for adjusting the geometric parameters of the piezoelectric transducers in order to achieve the desired values of natural frequencies. Results are presented in terms of sensor performance characteristics for various design parameters and modes of operation. The modeling assumptions adopted are tested experimentally on a cantilever-shape test vehicle.

The Impact of the Concurrent Engineering on the Transaction Processing Information System

Abstract The development of the production and control systems as well as the creation of the speech recognition and communication ones requires a close collaboration of the professionals of the large spectrum. It has been the challenge for the design and manufacturing engineers to work together as teams to provide all the links between: human knowledge and skills; logical organization; technology in order to improve quality performances while reducing costs of the manufacturing systems and processes. In this paper the integrated products and manufacturing systems design paradigm is used to analyse and characterise the complexity of the communication relations binding its participants and embedding their performances. The model decomposition often results in new peculiarities of the system, which were not taken into account at the previous stage of the system development. Examples are given of the “system-centred” socio-technological-psychological models in which the tasks’ distribution is accomplished in a concurrent way. This allows increasing the net efficiency and profitability of the integrated products and processes.