Solid State Phenomena Vol. 198

Abstract: In the first stage of the identification process was to build a model describing the system, using the measurement data recorded on input and output system [. The model was built without the knowledge of the mechanisms that occur in the process, only based on the relationship between the collected data. As an input parameter the defined type of motion was used, next converted to digital form by the real-time computer and sent to the axes control card. While the output signal was registered as a change of encoders position. Sampling time 20 ms was adopted. For each axis separately recorded measurements (signals were with different amplitudes and frequencies of motion tape device) [. In the next step the estimation was performed for the selection suitable algorithm, and the determination the parameters of model selected in the previous step [. The last step was to verify, to check the results of identification process. By comparing the signals obtained in response to a signal given the model of a registered object actual output signal, it is possible to visually estimate the accuracy of the identification and designation of the error. The last part of the article shows the results of various tests.

Abstract: The paper addresses the possibilities of applying the cam_gate system to product quality control. Particular attention is paid to the concept of the test stand simulating the operation of the product quality control automatic machine with the use of the CCD camera. Dimensional parameters of rollers were measured by means of a micrometer screw and the CCD camera at the simulation stand in the cam_gate system and the results of measurements were compared. The paper presents the cost system structure of an enterprises and factors affecting the selection of inspecting-sorting automatic machines in the aspect of the prescribed quality parameters which condition the optimal selection.

Abstract: This paper presents the practical results of the design analysis, commissioning, identification, sensor calibration, and tuning of an active magnetic bearing (AMB) control system for a laboratory gas blower. The presented step-by-step procedures, including modeling and disturbance analysis for different design choices, are necessary to reach the full potential of the prototype in research and industrial applications. The key results include estimation of radial and axial disturbance forces caused by the permanent magnet (PM) rotor and a discussion on differences between the unbalance forces resulting from the PM motor and the induction motor in the AMB rotor system.

Abstract: In the last twenty years, there has been significant progress in the design of rotating machinery equipped with smart components and embedded functions. This was accompanied by developments in actuators, sensors and power electronics technologies, advances in data acquisition and signal processing, as well as developments in control theory. This paper will provide a brief overview of the current state of art and it will illustrate examples of the applications of smart technologies applied to rotating machines. Several technologies, either most recently developed or under development will be presented, which involve active control and are relevant to smart solutions applied to rotating machinery.

Abstract: The article considers the previously presented manipulating mechanism for positioning of a microphone during acoustical measurements in anechoic chamber. Usually the aims of acoustical measurements in anechoic chamber are: estimation of Sound Power Level of the noise source, measurement of directional characteristics of an electroacoustical transducer, measurement of the sound diffusion characteristic of a given structure and a measurement of Sound Pressure Level on a given measurement grid. The specific of that kind of measurements brings up the need of measurement microphone positioning in many points of the measurement space accordingly to relevant standards. In most cases during the tests it is necessary to position the microphone in certain points on the hemisphere. In such cases utilizing of typical microphone stands impedes the measurement and extends the time needed for the tests. The presented manipulation system for a measurement microphone allows positioning the microphone on the hemisphere around the tested object as required by the standards on the Sound Power Level measurement. Its construction is a simple, rigid form aiming at little effect on the acoustic field inside the chamber whereas the control system and the software are targeted at the maximal flexibility that allows not only standard testing but also scientific research in freely selected scenarios. Since its initial introduction the system has been extended by an additional axis that is used for rotating the microphone, which allows its positioning on the line that is coincident with the centre of rotation of the turntable. Such an extension eliminates the problem of use of the corrections of the directional characteristics of the microphone when measuring the sound signal. The microphone can be positioned directly towards the source of the sound. The article briefly reviews the mechanical construction of the positioning mechanism and focuses on the structure of the control section of the drive system constructed in the manipulator. The method for cooperation of actuators and the control system is presented. Also the description is given for the internal structure of the multi-level control circuits built in the applied drives. Finally the structure of the control application is presented.

Abstract: Underactuated mechanical systems are systems with fewer control inputs than degrees of freedom. Determination of an input control strategy that forces an underactuated system to complete specified in time outputs (servo-constraints), whose number is equal to the number of inputs, can be a challenging task. Diversity of the servo-constraint problems is discussed here using a simple spring-mass system mounted on a carriage (two degrees of freedom, one control input, and one specified in time output). A formulation of underactuated system dynamics which includes the output coordinates is motivated, with the governing equations arising either as ODEs (ordinary differential equations) or DAEs (differential-algebraic equations). Solutions to the servo-constraint problem are then discussed with reference to so-called non-flat systems (with internal dynamics) and differentially flat systems (no internal dynamics). Some computational issues related to the ODE and DAE formulations are finally discussed, and relevant simulation results for the sample case study are reported.

Abstract: This publication presents a novel piezoelectric shunt damping circuit. It consists of a negative capacitance in parallel to a synchronized switch damping on inductor (SSDI) branch. This combination utilizes the increased piezoelectric coupling due to the negative capacitance together with the adaptive ability of the SSDI technique. This novel circuit is theoretically modelled using non-dimensional parameters, and optimum network parameters and the corresponding maximum damping is obtained. The increase in damping performance due to the negative capacitance is clearly highlighted. Theoretically, the energy dissipation can be increased unlimited when tuning the system at the stability boundary, given the system would still be excited to vibrations. However, due to imperfections and practical realization using operational amplifiers the increase is limited.

Abstract: The paper presents strength machine control system for characterization of fatigue properties of materials based on a new, recently defined, energy fatigue damage parameter. It is used in new procedure for precise determination of the fatigue characteristics of materials with the controlled strain energy density parameter. The new parameter distinguishes positive and negative values strain energy density histories during variable loading. In case of modern, cyclically unstable materials the new closed-loop control system of strength machine allows to univocally establish the relevant stress-strain based fatigue characteristic under bending and torsion. This control system has been implemented with the use of National Instruments LabVIEW software. The mechatronic stand based on fatigue machine for material testing under bending moment and torsion moment has been described and preliminarily material tests have been done.

Abstract: In this paper, the state-of-the-art AMB controller structure, with an outer centralized position control loop with reference currents and inner current control loops, is replaced with an outer control loop with force references and inner flux control loops. The linearization of the force actuators and different control schemes of the centralized outer control for the radial suspension are considered. The operation of the proposed control under a zero bias is verified by simulations. The proposed control solution can achieve a dynamic performance comparable with that of a controller with the classical bias current.

Abstract: The gain scheduling control scheme designing problem consists in selecting a set of appropriate operating points at which the linear controllers are determined, thus the interpolation scheme ensures expected control quality within the known range of system's parameters changes, when those parameters vary in relation to some exogenous variables used in a control system as the scheduling variables. The problem arises together with the number of scheduling variables correlated with the parameters variations, thus utilizing the iterative techniques to minimize a set of controllers can be unreliable. The problem of gain scheduling system designing is addressed in the paper to the anti-sway crane control system. The fuzzy interpolation is used to determine the gains of proportional-derivative controllers based on the scheduling variables, the rope length and mass of a payload suspended on a rope. The problem of rules base optimization and membership function parameters tuning is solved using genetic algorithm and pole placement method.