Applied Mechanics and Materials Vol. 816

Abstract: The article presents use of a linguistic fuzzy-logic control (LFLC) system for mechatronic system modelling and control. The presented applications were verified on real laboratory tasks in the Laboratory of Intelligent Systems at the University of Ostrava. The LFLC system was developed at the University of Ostrava, Institute for Research and Applications of Fuzzy Modeling. This technology enables users to describe the system behaviour and/or the control strategy as a set of fuzzy rules. Input and output variables scales are defined by contexts and their change allows using the same system description for systems with similar behaviour very easily.

Abstract: Our article deals with the possibility of using shape memory material (SMA − Shape Memory Alloy) to create an actuator of the mechanical element. The biggest advantage of the SMA actuators compared to those made of conventional materials is that they have the ability to generate relatively great force, are of low weight and small size.

Abstract: The article presents the analysis of the 1D flow of compressible fluid by means of analytical and numerical methods. The results from the solution showed that the calculation of dimensionless velocity for particular flow conditions varies in the area of subsonic flow only a very little, when using both methods. It was found that the dependence of dimensionless velocity on the relative duration of the investigated tunnel applies universally. For any proportional value of the tunnel length x/L and the constant ratio of outlet and inlet cross section of the tunnel level equal to 0.6474, the course of the dimensionless velocity for each tunnel, which satisfies the above condition, will always be the same. This means that also the nature of flow in any such tunnel will exhibit the same properties. This finding provides new knowledge from the analysis of air flow through a channel with a variable flow cross section.

Abstract: Gear teeth are deformed due to the load. The tooth deformation of spur gears is not constant for all examined teeth of gears. Tooth deformation is depends on the shape of the teeth, on the basic parameters of examined spur gear, such as the number of teeth, module gearing, pressure angle, gearing width, correction and modification of gearing.

Abstract: The paper presents a kinematic and dynamic analysis of a planar mechanism by means of the Cosmos Motion 2.85 program. Graphic dependence of kinematic and dynamic magnitudes of some points is given in dependence on the angle of rotation of the driving item and on the time.

Abstract: The primary aim of the research, whose results are presented in this article, was to investigate the process of visual identification of objects. The objects recognised under this research were passenger seats for mass transit applications. The system presented in this paper is intended to be incorporated in the production process control system. The problem under analysis is based on the need to recognise (identify) an object located in the process area of the machine before proceeding with the process. Neural network was chosen as the adaptive element due to a high degree of similarity between the semi-products. The function of the network was to check if correct element had been fed. The input data fed to the network was the information from processing the photo images of these elements. The results of research as presented in this article are based on a limited set of elements and present the method used for solving the task of identification.

Abstract: The paper deals with quadrocopter stability in vertical axis. At first, dynamic model of quadrocopter is introduced. In the paper are derived relations for control error in steady state for PD and PID controller. Based on dynamic model the PID controller is designed by optimizing method. Using designed controller the quadrocopter stability in vertical axis was simulated in software Matlab. In the conclusion the results of the simulation are shown.

Abstract: This article is focused on finding the most appropriate solution for eliminating vibrations that pose harmful influences in mechanical systems. To find this solution, the kinetic equations were generated from dynamical model of truck bodybuilding. The block diagram for natural frequencies calculation was made up out of these equations. Two solutions were suggested – to place flexible shaft coupling between high pressure pump and Power Take off and to connect the pump and Power Take Off directly with shaft. It is important to note that vibrations emerging may be reduced more effectively by using of the former solution – flexible shaft coupling.

Abstract: The works [1, 2] present the values of the force and moment of friction needed to disassemble the axisymmetric connection with oval and three-angular shape of cross-section of the shaft. These works additionally show the variable values of the Mises stresses and contact pressures. This paper presents research which is a continuation of the research program on the evaluation of the influence of cross-section deviations, radial deviations, and their compilations on the value of the contact area in the connection. The limited contact area has a decisive impact on functional and operational parameters of the connection. Point contact between the shaft and the hole is the reason of the reduction of load transmission. The paper concerns the connection between the shaft with four-angular shape of cross-section with the deviation T_w = 13 μm and the hub with the nominal roudness. The authors have proved the occurrence of variable values of the force and moment of friction during disassembling of the connection. The authors have also showed the occurrence of variable values of the reduced stresses and contact pressures.