Solid State Phenomena Vol. 198

Abstract: This paper presents the laminar flow of homogeneous liquids in crevices of smooth hydraulic resistance. The paper presents a theoretical model for the distribution of pressure in the gap and the flow rate through the slot hydraulic. The presented theoretical models for the distribution of pressure and flow in the gap on conventional hydraulic resistance of hydraulic joints, whose shape is related to the errors of their execution. In deriving the theoretical models, by introducing a variable height of the gap in the initial episode, was founded stream velocity profile variability in the hydraulic fluid retaining gap and zero values of local losses at the entrance to the slot. An analysis of the validity of the simplifications adopted in the given formulas for the distribution of pressure and flow in the hydraulic gap and on the basis provides guidelines for estimating the energy losses that occur cracks in the hydraulic resistance.

Abstract: This paper analyses the area in which synchronic operation of several pneumatic actuators connected by a rigid link exists. The minimum values of the supplied compressed air have been determined under which self-exciting vibrations appear in the system of several actuators. The influence of the transducers geometrical parameters on the variation law of motion of the system working organ has been investigated. It has determined that character of dependencies of peak-to-peak and frequency upon pressure of system is similar to character of dependencies separate transducer and that having picked up geometrical and dynamic parameters actuators it is possible to receive difficult (biharmonic) movement of system. This property can be applied in vibrostands meant for material or equipment trials and their vibrational processing.

Abstract: The recent trends in robotics and mechatronics necessitate for developing small-size multi-DOF motion systems. Piezoelectric actuators are one of the feasible solutions of this problem. An investigation of the contact point multicomponent oscillations of the beam type piezoelectric actuator with two-directional polarizations under different excitation regimes is presented in the paper. Polarization of the actuator has perpendicular directions on the first and second half of the actuator. Two-directional polarization of the actuator is used to achieve flexural oscillations of the actuator in two perpendicular planes. Superposition of longitudinal and flexural modes allows achieving oscillations of contact point in different planes. Electrodes of the actuator are divided into sections, and several excitation schemes are used to control a trajectory of the contact point movement. Numerical simulation and experimental study of piezoelectric actuator oscillations were performed. Elliptical motions of the contact point were obtained in different planes. Dependencies of contact point oscillation trajectories from excitation voltage phase and amplitude are determined at different excitation regimes.

Abstract: In the paper we present development work on an electromagnetic launcher (EML) for micro aerial vehicles (MAVs). The requirements of controlled take-off were shortly described and main advantages and disadvantages of the commonly used rubber and pneumatic launchers were enumerated. Concept, design and construction of the magnetic coil launcher were presented. The driving coils geometry determination with using the method, which was based on finite element method (FEM) and mechanical power analyses, was proposed. Finally, construction and assembling process of the device were described. In addition, the results of preliminary laboratory tests, control issues and controller target platform were mentioned.

Abstract: This paper summarises the results of numerical calculations of magnetic field and circuit parameters in an electromagnetic generator supplying a rotary MR damper. The design and operating principles of the generator are outlined. The distribution of the magnetic flux density vector is obtained, other parameters include its modulus, the magnetic flux from permanent magnets and time patterns of induced voltage and current in the control coil of the damper, power and energy of magnetic field in this coil at different rotational speeds of the induction with respect to the armature.

Abstract: The paper is devoted to the FEM modeling of a magnetic thrust bearing for the small power, high-speed microturbine, working in the Organic Rankine Cycle. The microturbine is used to produce electricity in small dissipated power generation systems.

Abstract: The paper deals with analysis of bearingless electric motor with surface-mounted permanent magnets. This kind of electric motor eliminate disadvantages of conventional motors, e.g. overall efficiency, friction forces, heat abstraction. In paper are shown mathematical analysis of bearingless motor and experimental investigation results of them. There are shown results of analysis of magnetic flux density distribution in bearingless motor by finite element method, too. This kind of motor was elaborated and investigated in Military University of Technology.

Abstract: In this paper the OptiTrack-Motion Capture System, the Microsoft KINECT sensor system and SHIMMER sensors are evaluated with respect to their applicability to the measurement of human locomotion in 3D-space. The both sensor systems KINECT and SHIMMER are evaluated with respect to the accuracy and precision of any measurement, to their repeatability and reliability of raw data, to the consistency of the underlying kinematical model. The OptiTrack system is used only as a reference for the other two sensor types (gold standard). Several experiments are explained and analyzed. Problems and ways to overcome them as well as their adaptability to different application fields are discussed.

Abstract: The article presents the structure of the developed pneumatic propellant system for impact tests particularly conducted in the aviation. The solution is intended for the realization of experimental tests enabling the simulation and recreation of the event of collision of the aircraft, or other means of transport, with the solid object or a bird in motion. The projectile thrower has been designed in form of a 250 mm pneumatic cannon. The size and the energy parameters of the cannon enable the objects weighing several kilograms to be thrown with the speed reflecting the actual collision of the aircraft with a big bird, both in the areas of subsonic and supersonic crash speed. In order for the complex realisation of the impact tests, the structure of the test system for impact tests with the option to record the event by means of a synchronised vision path and an impact force measurement path, has been developed.

Abstract: The paper describes the construction and the principle of operation of a planar aerostatic two-coordinate relative base. The physical model and the mathematical description of a planar aerostatic two-coordinate relative base are presented. Stages of the computer simulation of the planar aerostatic two-coordinate base and the computer simulation results are presented.