: This paper examines a linear-quadratic stabilization system for a canard-controlled missile. An analytical method for selecting the weighting elements of the gain matrix in the feedback loop is also proposed, eliminating the need for an iterative solution to the Riccati equation. The proposed solution was evaluated using simulation tests.
{"title":"A LINEAR-QUADRATIC STABILIZATION SYSTEM FOR A CANARD-CONTROLLED MISSILE","authors":"W. Bużantowicz","doi":"10.21495/71-0-73","DOIUrl":"https://doi.org/10.21495/71-0-73","url":null,"abstract":": This paper examines a linear-quadratic stabilization system for a canard-controlled missile. An analytical method for selecting the weighting elements of the gain matrix in the feedback loop is also proposed, eliminating the need for an iterative solution to the Riccati equation. The proposed solution was evaluated using simulation tests.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127125030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
: This paper aims to the modelling and investigation of sub-synchronous vibrations of a rotor supported on poorly lubricated journal bearings. Bores for an oil supply are located in the lower halves of bearing shells. It is shown that the poor lubrication of the described bearings may lead to an occurrence of stable vibrations at the frequency ca. 0.9 to the rotor speed. Simulations are performed using a multi-body approach for modelling rotating systems. Forces acting in journal bearings are evaluated employing a mass-conserving finite element solution of the Reynolds equation.
{"title":"SUB-SYNCHRONOUS VIBRATIONS OF A ROTOR SUPPORTED ON POORLY LUBRICATED JOURNAL BEARINGS","authors":"L. Smolík, P. Polach, J. Rendl","doi":"10.21495/71-0-339","DOIUrl":"https://doi.org/10.21495/71-0-339","url":null,"abstract":": This paper aims to the modelling and investigation of sub-synchronous vibrations of a rotor supported on poorly lubricated journal bearings. Bores for an oil supply are located in the lower halves of bearing shells. It is shown that the poor lubrication of the described bearings may lead to an occurrence of stable vibrations at the frequency ca. 0.9 to the rotor speed. Simulations are performed using a multi-body approach for modelling rotating systems. Forces acting in journal bearings are evaluated employing a mass-conserving finite element solution of the Reynolds equation.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129628744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Adorna, M. Neuhäuserová, T. Fíla, J. Falta, P. Koudelka, P. Zlámal
: In this paper, digital image correlation method (DIC) is introduced as a tool for evaluation of high strain-rate experiments perfomed using Hopkinson Bar apparatus. Samples of advanced cellular materials with predefined periodic structure and negative Poisson’s ratio (auxetic structures) were investigated in this study. In-house Hopkinson Pressure Bar apparatus was used to perform the impact experiments and the experimental setup was observed using a pair of high-speed cameras. Custom DIC software tool was used to evaluate high-speed cameras records. Selected representative results of DIC applications on Hopkinson Bar experiments are provided in this paper.
{"title":"PROCESSING OF HIGH-SPEED CAMERA IMAGES OF HOPKINSON BAR EXPERIMENTS USING DIGITAL IMAGE CORRELATION","authors":"M. Adorna, M. Neuhäuserová, T. Fíla, J. Falta, P. Koudelka, P. Zlámal","doi":"10.21495/71-0-29","DOIUrl":"https://doi.org/10.21495/71-0-29","url":null,"abstract":": In this paper, digital image correlation method (DIC) is introduced as a tool for evaluation of high strain-rate experiments perfomed using Hopkinson Bar apparatus. Samples of advanced cellular materials with predefined periodic structure and negative Poisson’s ratio (auxetic structures) were investigated in this study. In-house Hopkinson Pressure Bar apparatus was used to perform the impact experiments and the experimental setup was observed using a pair of high-speed cameras. Custom DIC software tool was used to evaluate high-speed cameras records. Selected representative results of DIC applications on Hopkinson Bar experiments are provided in this paper.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129215123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"NUMERICAL SIMULATION OF SEAL LEAKAGE FLOWS IN AXIAL TURBINE STAGE","authors":"P. Straka, J. Pelant","doi":"10.21495/71-0-343","DOIUrl":"https://doi.org/10.21495/71-0-343","url":null,"abstract":"","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127899163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article is devoted to the study of the wear problem of elastic layer with nonuniform coating by the system of plane rigid punches. It is assumed that punches has different lengths. A mathematical model of the problem is obtained. It is a system of mixed integral equations (with Volterra and Fredholm operators) with additional conditions. The analytical solution of the problem is presented. In the solution coating nonuniformity is represented by separate factor. It allows one to make calculations with high accuracy even if coating nonuniformity is described by rapidly changing function.
{"title":"WEAR OF ELASTIC FOUNDATION WITH COATING BY SYSTEM OF RIGID PUNCHES","authors":"K. Kazakov","doi":"10.21495/71-0-181","DOIUrl":"https://doi.org/10.21495/71-0-181","url":null,"abstract":"This article is devoted to the study of the wear problem of elastic layer with nonuniform coating by the system of plane rigid punches. It is assumed that punches has different lengths. A mathematical model of the problem is obtained. It is a system of mixed integral equations (with Volterra and Fredholm operators) with additional conditions. The analytical solution of the problem is presented. In the solution coating nonuniformity is represented by separate factor. It allows one to make calculations with high accuracy even if coating nonuniformity is described by rapidly changing function.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"162 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122699137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Keywords: The paper presents mathematical modelling of contactless ECM of conical surfaces. Applying the known-from-literature equation describing the evolution of the machined surface shape and the flow equation for the mixture or electrolyte and hydrogen in the interelectrode gap, there were determined parameters characteristic for ECM. For the machining parameters set, the calculations results for selected ECM parameters are shown in diagrams.
{"title":"ELECTROCHEMICAL MACHINING OF CONICAL SURFACES","authors":"J. Sawicki","doi":"10.21495/71-0-327","DOIUrl":"https://doi.org/10.21495/71-0-327","url":null,"abstract":"Keywords: The paper presents mathematical modelling of contactless ECM of conical surfaces. Applying the known-from-literature equation describing the evolution of the machined surface shape and the flow equation for the mixture or electrolyte and hydrogen in the interelectrode gap, there were determined parameters characteristic for ECM. For the machining parameters set, the calculations results for selected ECM parameters are shown in diagrams.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123291885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Autonomous mobile robots consists of various software modules to achieve given goal, including solving complex navigation tasks as localization, mapping or path planning. These tasks are highly dependent on the quality of data measured and gathered from hardware subsystems. Using Robot Operating System (ROS) as integration basis reduces the development effort and time to market. While ROS framework itself is considered as reliable and stable to run even soft real-time tasks, in case of any internal failures on data misreadings can be problematic to debug or even identify the problem for common user. Due to this unpleasant situations we develop a virtual assistant, internally represented as diagnostic expert system, to help users to identify and possibly fix the problem.
{"title":"REAL-TIME DIAGNOSTICS FOR ROS RUNNING SYSTEMS BASED ON PROBABILISTIC PATTERNS IDENTIFICATION","authors":"S. Vechet, J. Krejsa","doi":"10.21495/71-0-383","DOIUrl":"https://doi.org/10.21495/71-0-383","url":null,"abstract":"Autonomous mobile robots consists of various software modules to achieve given goal, including solving complex navigation tasks as localization, mapping or path planning. These tasks are highly dependent on the quality of data measured and gathered from hardware subsystems. Using Robot Operating System (ROS) as integration basis reduces the development effort and time to market. While ROS framework itself is considered as reliable and stable to run even soft real-time tasks, in case of any internal failures on data misreadings can be problematic to debug or even identify the problem for common user. Due to this unpleasant situations we develop a virtual assistant, internally represented as diagnostic expert system, to help users to identify and possibly fix the problem.","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"51 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130694135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Vlasák, Z. Chára, V. Matoušek, M. Kesely, J. Konfršt, M. Mildner
{"title":"EFFECT OF PIPE INCLINATION ON LOCAL CONCENTRATION AND FLOW BEHAVIOUR OF SETTLING SLURRY","authors":"P. Vlasák, Z. Chára, V. Matoušek, M. Kesely, J. Konfršt, M. Mildner","doi":"10.21495/71-0-391","DOIUrl":"https://doi.org/10.21495/71-0-391","url":null,"abstract":"","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"336 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115456406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A STOCHASTIC SOLUTION TO THE DYNAMICS OF LOAD MOVEMENT ON A TRANSPORT LINE","authors":"P. Pavlíček, K. Frydrýšek","doi":"10.21495/71-0-275","DOIUrl":"https://doi.org/10.21495/71-0-275","url":null,"abstract":"","PeriodicalId":197313,"journal":{"name":"Engineering Mechanics 2019","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123102843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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