Solid State Phenomena Vols. 147-149

Abstract: An in-house pin-on-disc apparatus is designed and constructed to perform the tests and the design of experiments technique is utilized to determine the effect of vibration, amplitude of vibration, surface roughness, and sliding speed and their cross influence on coefficient of friction for 304 stainless steel and Alloy 6061 Aluminum. The design is performed using response surface method (RSM). The coefficient of friction (CoF) is analyzed as a nonlinear function of the factors and predicted by a second-order polynomial equation. Results suggested that the presence of vibration affect the friction function CoF considerably for both metals. The friction function linearly decreases with the increases of vibration and amplitude of vibration, non-linearly decreases with the increases of sliding speed and linearly increases with the increases of the surface roughness until the middle range is reached and then there is non-linearly decrease thereafter. Similar trends of friction functions are observed for Alloy 6061 Aluminum with a reduction of almost 15% except for the case with amplitude of vibration where the variation showed more significant affect on the friction function when Alloy 6061 Aluminum disk is used.

Abstract: Traverse cylindrical grinding productivity and accuracy depend on many factors of rough, fine and spark out grinding. Evaluation of all these factors at manual calculation of the process plan is impossible, for that reason the engineer technologist selects the cutting rates approximately, and they are far from optimal. We have deduced equations for calculation of optimal cutting rates for that purpose. Because of task complexity the computer program was designed for calculations which is described in this paper.

Abstract: The aim of this paper is to present a new interdisciplinary methodology and software tools realized and configured for the analysis and optimization of the heteropolar radial Active Magnetic Bearing (AMB) construction. Due to several possible AMB configurations for the particular application, the designer needs to be supported by modelling and simulation tools at the decision stage. The designed software model of AMB accelerates the prototype design and minimizes its initial costs. In this paper the proposed solution and software environment are discussed together with its advantages and disadvantages. The analytical calculations of the AMB stator geometry are used as a starting point for the optimization procedure. The geometry constraints along with the AMB operational parameters are formulated. The AMB stator is characterized by many dimensions defining the magnetic field path, which are the pole width, the pole height, the stator radiuses: the external, internal and the rotor side. The coils are represented by closed shapes located at the pole sides. In the coil area a current density is defined and used in the optimization process. The AMB performance and parameters strongly depend on the air gap size which could be selected manually or fitted automatically due to the rotor size and weight. The electromagnetic force generated by the proposed stator geometry depends on the rotor-bearing air gap. For the proposed parametric description of the AMB geometry the choice of optimization strategy is studied to satisfy the selected quality criterion. To simplify calculations a quarter of the AMB construction is under consideration. The designed construction variants and examples of optimization are presented.

Abstract: The article presents the project design flow that leads to the implementation of the robust controller law in the FPGA chip. The designed robust FPGA controller is going to be used in the heteropolar active magnetic bearing system. The hardware and software architectures of the designed controller are presented. The hardware consists of the market available Spartan-3 Development Board and two specially designed A/D and D/A converters boards. The software architecture is made of several VHDL entities that are translated into the target FPGA chip. The results of the experimental preliminary tests show that the dynamic properties of the designed controller are very good and the authors hope that the dynamic performance, especially the stability of the whole active magnetic bearing system, will improve.

Abstract: With this paper the suspension of an elliptic rotor is considered. The operating area, electromagnetic forces and the rotor shape are analyzed along with the static and dynamic properties of the levitated rotor to obtain the required performance. The linear and non-linear stabilizing controllers are suggested to obtain stable levitation. An interdisciplinary approach for modelling and simulation tasks is proposed.

Abstract: In this article the storage systems: capacitors, batteries and flywheel energy storage are described. The flywheel energy storage will be described precisely and compared with other energy storage technologies.

Abstract: This paper shows the practical significance of the nonholonomic constraints that allow us to assess the processes occurring in the real machine units and to determine parameters of motions more accurately.

Abstract: This paper deals with an optimal design of an electromagnetic energy harvesting generator for supplying wireless sensors with energy. The developed device is complex mechatronic system which generates an electrical power from an ambient low frequency mechanical vibration by use of a suitable electromagnetic generator. This device is excited by ambient mechanical vibration and electrical energy is harvested due to Faraday’s law. The design of this vibration power generator results from development cycles and the final generator can provide sufficient electrical energy for wireless sensors. The vibration power generator is tuned up to frequency of vibration 17 Hz and harvested output power depends non-linearly on level of vibration. The vibration power generator operates in level of vibration 0.1 – 1 G peak and output power is in range 2 – 25 mW.

Abstract: The authors provide inverse method algorithm for invention mechatronic systems in vibrotechnics. The main difference of this method compared to a simple analysis method is that initial subsystem is solved before a synthesis of real system optimal control task for abstract. After the calculations optimal control law is found, which allows synthesizing series of structural schemes for real systems to close initial subsystem. It is also shown that near the optimal control excitation new structural schemes may be found within three kinds of strongly non-linear (impact) systems: systems with excitation as a time function; systems with excitation as a function of phase coordinates only; systems with mixed both excitations.

Abstract: This paper describes the process of a coil launcher parameters selection. Objective function Θ was defined and crucial variables were sought. The electro-mechanical system consisting of a copper coil and a ferromagnetic core was designed. Displacement of the core was computed. The magnetic force and coil inductance were calculated in many core position in relation to solenoid. Simulations were done by means of Finite Elements Method (FEM). The model parameters were being changed and the best system geometry was sought. In order to achieve better legibility, the research results were shown in the graphs. Selection process turned out to be very complex. In order to determine the best device parameters, the currents thermal effects should be taken into consideration. As the final conclusion some constructional conceptions of the magnetic launcher were proposed. The research will be continued to improve the coil launcher optimization process. The aim of future investigations is to achieve greater magnetic force and lower inductance of the electro-mechanical system.