Preliminary layout of the main technological equipment of a self-propelled machine with a rod mechanism for installing and fixing the end tower for a mobile ropeway

Mobile ropeways for carrying out transport operations, formed with the help of terminal transport units connected by a single cable system on the basis of self-propelled wheeled or tracked chassis of increased carrying capacity and cross-country ability, are a promising type of lifting and transport equipment that ensures the rapid deployment of the necessary technological means. The article discusses the issues of preliminary arrangement of the rod mechanism for installation and fixation in the working position of the end tower using a folding rod consisting of two articulated links for a constructive variant of the outrigger placement of the tower on a rotary platform. The design and principle of operation of the rod mechanism is considered. A mathematical model has been developed that provides the required normative vertical dimension of a self-propelled vehicle for the purpose of its safe independent movement to the deployment site on general-purpose highways. The analysis of the influence of normative dimensional requirements, the structural dimensions of the bearing frame of the chassis and the height of the end tower on the main structural dimensions of the articulated folding rod in the transport position is carried out.

Analysis and Experimental Investigation of Vibration Characteristics of Rotary Platform of Hydraulic Excavator under Complex Working Conditions

The rotary platform is the load-bearing substrate of a hydraulic excavator. The dynamic characteristics of the rotary platform directly affect the reliability and safety of the whole machine of a hydraulic excavator. In this work, the characteristics of the main external excitations acting on the hydraulic excavator such as the engine excitation, pressure pulsation excitation of the piston pump, inertial excitation of the working device, and road excitation are analyzed. The vibration transmission paths under the action of external excitations are ascertained. A vibration test method for the rotary platform of the hydraulic excavator is proposed. The vibration characteristics of the rotary platform under complex working conditions are researched, and the internal relationships between the vibration characteristics of the rotary platform and the engine excitation, pressure pulsation excitation of the piston pump, and road excitation are analyzed experimentally. The results show that the rotary platform is subjected to different excitations when it is under different working conditions. Moreover, the internal relationships between the dynamic characteristics of the rotary platform and the external excitation characteristics can be discovered by analyzing the vibration signals of the rotary platform, and the dynamic characteristics of the whole machine of the hydraulic excavator can be deeply studied based on the vibration characteristics of the rotary platform.

Three-Probe Error Separation with Chromatic Confocal Sensors for Roundness Measurement

In this study, three-probe error separation was developed with three chromatic confocal displacement sensors for roundness measurement. Here, the harmonic suppression is discussed first to set suitable orientation angles among three sensors. Monte Carlo simulation is utilized to test the error separation and optimize the orientation angles and off-axial distance. The experimental setup is established using chromatic confocal sensors with a precise rotary platform. The experimental results show that the measured roundness with an orientation-angle combination of (0°, 90.1°, and 178.6°) is much better than that of another nonoptimal selection (0°, 90.4°, and 177.4°). The roundness error is only 0.7% between the proposed measurement system and an expensive ultraprecision roundness meter. Furthermore, it is proven that the eccentricity distance should be decreased as small as possible to improve the measurement accuracy. In sum, this paper proposes a feasible method for roundness measurement with reliable simulations, easily integrated sensors, and an ordinary precision rotary platform.

Экспериментальное определение вибрационных характеристик рабочих лопаток турбин помехоустойчивым цифровым спекл-интерферометром

The paper notes the wide possibilities and high efficiency of vibration diagnostics of parts and assemblies of power units by the method of electronic speckle interferometry (ESI), shows the feasibility of developing and improving methods for obtaining speckle interferograms of vibrating objects. A patented by the authors' scheme of a digital speckle interferometer (DSI) for determining the dynamic parameters of products is presented. The diffuse reference wave greatly simplifies its alignment, mainly the aligned channels of propagation of interfering beams determine the resistance to mechanical and thermal disturbances, and the separate beam splitter and diffuser make it easy to optimize the optical scheme for the object under study. Speckle interferograms are obtained by speckle correlation methods and a developed method for determining the contrast of the dynamic speckle pattern. It does not impose special requirements on the parameters of the video system, does not require the use of a specialized video camera, and allows, by using a rotary platform, to organize a panoramic view of the oscillatory forms of asymmetric structures. The use of this method in combination with the proposed optical scheme provides an express analysis of products in off-bench conditions. The increased noise immunity of the installation allows the determination of the spectrum of frequencies and vibration modes (SFVM) of samples under free boundary conditions, which is rarely realized in interferometry. The paper presents examples of such speckle interferograms, the expediency of obtaining which is important in the resonance study of the elastic properties of the material and vibration resonance flaw detection. The implemented software and hardware solutions increase the resolution and visibility of the band patterns; facilitate their quantitative interpretation and the extraction of numerical information on the distribution of vibration amplitudes. The area of scientific interests and the specificity of the author's developments have determined the preferential adaptation of the proposed device with a complex of software and methodological developments for vibration testing of gas turbine engine (GTE) blades.

COMPACT ROTARY PLATFORM AS A UNIVERSAL LABORATORY STAND

A single axis rotary platform is distinguished among the laboratory equipment for testing gyroscopic devices and systems and their sensitive elements. An overview of the design principles of industrially developed stands for the study of static and dynamic characteristics of gyroscopic devices and systems is provided. The scheme of design of the universal laboratory stand is suggested as the compact rotary platform for research of static and dynamic characteristics of micromechanical gyroscopes and accelerometers as sensors of angular speed. The physical components of such a stand and technical and technological problems of its practical implementation are reviewed. The proposed laboratory stand is considered as a cyberphysical system where computing components play a crucial role in determining the parameters of the system and the studied micromechanical sensors. For this purpose, in addition to the physical control loop of the electric drive to ensure the stability of the angular velocity of the platform, an independent measuring loop is considered for analytical determination of system parameters, including the studied micromechanical sensors. The versatility of the stand is ensured by solving the inverse problems, namely determining in the process of testing static and dynamic characteristics of the electric drive and measuring sensors that work on various physical principles. It is assumed that, in addition to solving practical problems of micromechanical sensors in the development of the appropriate information interface of the virtual device, a compact laboratory stand can be effectively used in the educational process during laboratory work in relevant disciplines of instrument making direction.