Applied sciences

Archive of Mechanical Engineering

Content

Archive of Mechanical Engineering | 2009 | vol. 56 | No 3 |

Download PDF Download RIS Download Bibtex

Abstract

The paper presents a spatial model of the satellite antenna with an arbitrary number of flexible arms. Such a system is an example of an open kinematic chain with a tree-like structure. The modification of the rigid finite element method is used to discretise flexible links. The equations of motion are derived from the Lagrange equations and the motion of the system is described using joint coordinates and homogenous transformations. Numerical simulations have been carried out to analyse how the method of extending the arms influences the dynamics of the system.

Go to article

Authors and Affiliations

Krzysztof Augustynek
Iwona Adamiec-Wójcik
Edmund Wittbrodt
Download PDF Download RIS Download Bibtex

Abstract

Cranes belong to underactuated mechanical systems, an important subclass of nonlinear control systems typified by fewer control inputs than the degrees of freedom. The usual performance goal of a crane is to execute a desired motion of the load, specified by as many outputs as the control inputs. The challenging task of inverse simulation study, in which control of the underactuated system subject to execute the partly specified motion is determined, is usually formulated in independent variables. In this paper, a dependent variable formulation is motivated and developed. Compared to the independent variable formulation, the use of dependent variables leads to much simpler governing equations, and their effective number is reduced. The developed formulation is illustrated by a simulation model of an overhead crane executing a rest-to-rest maneuver of the load along a specified curvilinear trajectory.

Go to article

Authors and Affiliations

Wojciech Blajer
Krzysztof Kołodziejczyk
Download PDF Download RIS Download Bibtex

Abstract

In this work, a novel approach to designing an on-line tracking controller for a nonholonomic wheeled mobile robot (WMR) is presented. The controller consists of nonlinear neural feedback compensator, PD control law and supervisory element, which assure stability of the system. Neural network for feedback compensation is learned through approximate dynamic programming (ADP). To obtain stability in the learning phase and robustness in face of disturbances, an additional control signal derived from Lyapunov stability theorem based on the variable structure systems theory is provided. Verification of the proposed control algorithm was realized on a wheeled mobile robot Pioneer–2DX, and confirmed the assumed behavior of the control system.

Go to article

Authors and Affiliations

Zenon Hendzel
Marcin Szuster
Download PDF Download RIS Download Bibtex

Abstract

Parallel computers are becoming more available. The natural way to improve computational efficiency of multibody simulations seems to be parallel processing. Within this work we are trying to estimate the efficiency of parallel computations performed using one of the commercial multibody solver. First, the short theoretical outline is presented to give the overview of modeling issues in multibody dynamics. Next, the experimental part is demonstrated. The series of dynamics analyses are carried out. The test mechanisms with variable number of bodies are used to gather the performance results of the solver. The obtained data allow for estimating the number of bodies which are sufficient to gain benefits from parallel computing as well as their level. The parallel processing profits are taken into account in the case of contact forces present in the system. The performance benefits are indicated, when the multilink belt chain is simulated, in which contact forces are included in the model.

Go to article

Authors and Affiliations

Paweł Malczyk
Janusz Frączek
Download PDF Download RIS Download Bibtex

Abstract

Moving with the wheelchair can be a serious problem, especially when the obstacle occurs on its way. An alternative solution would be to equip the wheelchair with appropriate mechanical device, thanks to that it becomes possible to overcome barriers such as kerbs or doorsteps. In this paper, the authors present an idea of mechanism overcoming barriers by the wheelchair. Type and geometrical synthesis have been presented. The mechanism is modelled in a multibody computer analysis system and sample simulation research results are reported.

Go to article

Authors and Affiliations

Jacek Bałchanowski
Jarosław Szrek
Sławomir Wudarczyk
Download PDF Download RIS Download Bibtex

Abstract

In order for a quadruped robot to be able to move on wheels while keeping its platform in horizontal position, and to walk, the kinematic system of its limbs should be so designed that each of the wheels has at least four degrees of freedom. Consequently, the designed system will have many DOFs and many controlled drives. This paper presents a novel solution in which, thanks to a suitable limb kinematic system geometry, the number of drives for the robot travel function, i.e. travelling on an uneven surface with the robot platform kept horizontal, has been reduced by four which are used only for walking. The robot structure, the required geometry of the limb links and the driving torque characteristics are presented. Moreover, an idea of the control system is sketched. Finally, selected results of the tests carried out on the robot prototype are reported.

Go to article

Authors and Affiliations

Antoni Gronowicz
Jarosław Szrek
Download PDF Download RIS Download Bibtex

Abstract

The peculiarity of offshore cranes, i. e. cranes based on ships or drilling platforms, is not only a significant motion of their base, but also the taut-slack phenomenon. Under some circumstances a rope can temporarily go completely slack, while a moment later, the force in the rope can increase to nominal or even higher value. Periodic occurrence of such phenomena can be damaging to the supporting structure of the crane and its driver. In the paper, mathematical models of offshore cranes that allow for analysis of the taut-slack phenomenon are presented. Results of numerical calculations show that the method of load stabilization proposed by the authors in their earlier works can eliminate this problem.

Go to article

Authors and Affiliations

Andrzej Maczyński
Stanisław Wojciech
Download PDF Download RIS Download Bibtex

Abstract

The paper presents selected methods used for estimation the unknown geometrical parameters of a spatial mechanism model, used to describe the position and orientation of the end-effector, for example the coordinates of the center points of spherical joints, link dimensions etc. These data are necessary when dealing with computer simulation of any mechanism. The parameters are estimated based on coordinate measurements of selected points, located on the real mechanism links, using a portable manipulator with serial structure composed of 6 revolute joints and a spherical probe, but other techniques of acquiring point coordinates are applicable as well. The described methods can be used in the cases of a disassembled link, an assembled mechanism and redundant data sets. The methods are characterized by accuracy and robustness in the presence of different levels of noise, stability with respect to degenerate data sets, and low computation time. Special attention is paid to the case when the wanted parameters are hard to measure directly. Numerical examples are presented dealing with 5-link mechanism used to guide front wheels of a car.

Go to article

Authors and Affiliations

Józef Knapczyk
Michał Maniowski
Download PDF Download RIS Download Bibtex

Abstract

A backward tucked somersault from the standing position is analyzed in this study. The used computations were based on a three-dimensional model of the human body defined in natural coordinates. The net torques and internal reactions occurring at the ankle, knee, hip, upper trunk-neck and neck-head joints were obtained by inverse dynamics. The achieved results confirmed the significant loads at the joints at the beginning of the landing phase and revealed the way the analyzed stunt was controlled. It was also shown that the natural coordinates provide a useful environment for modeling spatial biomechanical structures.

Go to article

Authors and Affiliations

Adam Czaplicki

Editorial office

Editor-in-Chief

Prof. Marek Wojtyra, Warsaw University of Technology, Poland

 

Editorial Board

Prof. Krzysztof Arczewski, Warsaw University of Technology, Poland

Prof. Janusz T. Cieśliński, Gdańsk University of Technology, Poland

Prof. Antonio Delgado, LSTM University of Erlangen-Nuremberg, Germany

Prof. Peter Eberhard, University of Stuttgart, Germany

Prof. Jerzy Maciej Floryan, The University of Western Ontario, Canada

Prof. Janusz Frączek, Warsaw University of Technology, Poland

Prof. Tadeusz Ryszard Fodemski, Technical University of Lodz, Poland

Prof. Zbigniew Kowalewski, Institute of Fundamental Technological Research, Polish Academy of Sciences, Poland

Prof. Zenon Mróz, Institute of Fundamental Technological Research, Polish Academy of Sciences, Poland

Prof. Andrzej J. Nowak, Silesian University of Technology, Poland

Dr. Andrzej F. Nowakowski, The University of Sheffield, United Kingdom

Prof. Jerzy Sąsiadek, Carleton University, Canada

Prof. Jacek Szumbarski, Warsaw University of Technology, Poland

Prof. Tomasz Wiśniewski, Warsaw University of Technology, Poland

Prof. Günter Wozniak, Chemnitz University of Technology, Germany

 

Assistant to the Editor

Małgorzata Broszkiewicz, Warsaw University of Technology, Poland

 

Editorial Advisory Board

Prof. Alberto Carpinteri, Politecnico di Torino, Italy

Prof. Fernand Ellyin, University of Alberta, Canada

Prof. Feng Gao, Shanghai Jiao Tong University, P.R. China

Prof. Emmanuel E. Gdoutos, Democritus University of Thrace, Greece

Prof. Gregory Glinka, University of Waterloo, Ontario, Canada

Prof. Andrius Marcinkevicius, Vilnius Gedeminas Technical University, Lithuania

Prof. Manuel José Moreira De Freitas, Instituto Superior Tecnico, Portugal

Prof. Andrzej Neimitz, Kielce University of Technology, Poland

Prof. Thierry Palin-Luc, Arts et Métiers ParisTech, Institut Carnot Arts, France

Prof. Andre Pineau, Centre des Matériaux, Ecole des Mines de Paris, France

Prof. Narayanaswami Ranganathan, LMR, Ecole Polytechnique de l'Université de Tours, France

Prof. Jan Ryś, Cracow University of Technology, Poland

Prof. Adelia Sequeira, Technical University of Lisbon, Portugal,

Prof. Józef Szala, University of Technology and Life Sciences in Bydgoszcz, Poland

Prof. Edmund Wittbrodt, Gdańsk University of Technology, Poland

Prof. Jens Wittenburg, Karlsruhe Institute of Technology, Germany

Prof. Stanisław Wojciech, University of Bielsko-Biała, Poland

 

Language Editor

Lech Śliwa, Institute of Physiology and Pathology of Hearing, Warsaw, Poland

  

Contact

ARCHIVE OF MECHANICAL ENGINEERING

Editorial Office:

Institute of Aeronautics and Applied Mechanics, Warsaw University of Technology

Nowowiejska 24, Room 132, 00-665 Warsaw, Poland

Phone:  (+48) 22 234 7448, fax: (+48) 22 628 25 87,

E-mail: ame.eo@meil.pw.edu.pl

https://www.editorialsystem.com/ame

www.journals.pan.pl/ame

Instructions for authors

About the Journal
Archive of Mechanical Engineering is an international journal publishing works of wide significance, originality and relevance in most branches of mechanical engineering. The journal is peer-reviewed and is published both in electronic and printed form. Archive of Mechanical Engineering publishes original papers which have not been previously published in other journal, and are not being prepared for publication elsewhere. The publisher will not be held legally responsible should there be any claims for compensation. The journal accepts papers in English.

Archive of Mechanical Engineering is an Open Access journal. The journal does not have article processing charges (APCs) nor article submission charges.

Original high quality papers on the following topics are preferred:

  • Mechanics of Solids and Structures,
  • Fluid Dynamics,
  • Thermodynamics, Heat Transfer and Combustion,
  • Machine Design,
  • Computational Methods in Mechanical Engineering,
  • Robotics, Automation and Control,
  • Mechatronics and Micro-mechanical Systems,
  • Aeronautics and Aerospace Engineering,
  • Heat and Power Engineering.

All submissions to the AME should be made electronically via Editorial System - an online submission and peer review system at: https://www.editorialsystem.com/ame

More detailed instructions for Authors can be found there.

This page uses 'cookies'. Learn more