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Über dieses Buch

The first Workshop on Mechanisms, Transmissions and Applications -- MeTrApp-2011 was organized by the Mechatronics Department at the Mechanical Engineering Faculty, “Politehnica” University of Timisoara, Romania, under the patronage of the IFToMM Technical Committees Linkages and Mechanical Controls and Micromachines.

The workshop brought together researchers and students who work in disciplines associated with mechanisms science and offered a great opportunity for scientists from all over the world to present their achievements, exchange innovative ideas and create solid international links, setting the trend for future developments in this important and creative field.

The topics treated in this volume are mechanisms and machine design, mechanical transmissions, mechatronic and biomechanic applications, computational and experimental methods, history of mechanism and machine science and teaching methods.



History of Mechanisms and Machine Science and Teaching Methods


On the Evolution of Graphical Representation of Gears

In this paper, a historical evolution of graphical representation of gear designs is reported as a short survey by using significant drawings bath in the history of gear systems and design standards. A graphical representation of gear systems has evolved from a pictorial illustration towards a synthetic drawing of functionality and characteristics of gears that is today summarised in international standards. Those standards as from ISO and Italian UNI codes are still based on graphical schematic representation of gear characteristics with pictorial representation for an intuitive understanding of an intuitive understanding of main features of gear designs. A historical study is focused on the last century practical application of this gear representative.
M. Ceccarelli, M. Cigola

Kurt Hain and Walther Meyer zur Capellen: A View from Aachen at Two Shapersof German Mechanism Theory

The occasion of the 100th Birthday of Dr.-Ing. e.h. Kurt Hain is the starting point of the author to shed a light on two shapers of mechanism theory in Germany: Kurt Hain and Walther Meyer zur Capellen. Considering the restricted time and space of this contribution this can only just tackle the full story. Two joint publications of the two protagonists will be taken as basis of this paper. It will be shown that for both the scientific career was affected by their education, their technical and mathematical interest (or better genius) as well as their work enthusiasm. Two different people have made quite an impact on the development of mechanism theory in the decades after World War II.
B. Corves

thinkMOTION – DMG-Lib Goes Europeana

In 2011 the thinkMOTION project started. It focuses on making knowledge in the field of motion systems accessible to a broad public. The collected material covers forgotten treasures as well as current day research results. Different kinds of representation are supported, most notably books, articles, patents, images, videos, interactive animations and formalized mechanism descriptions. From the technical point of view the work in thinkMOTION is based on the DMG-Lib which was started as a German national project. Now workflow and tools were adapted to fit the needs of the work on European level. The content is collected on the DMG-Lib platform and presented to the international audience in different ways. The most important way for thinkMOTION is to make all the content accessible via Europeana, a multi-lingual online collection of millions of digitized items. This article focuses on the thinkMOTION workflow and the support of multilingualism.
U. Döring, R. Brecht, T. Brix

Multilingual Illustrated μ-Thesaurus in Mechanisms Science

In order to ensure a uniform indexing of technical information and a coordinated search engine in the field of mechanisms science, it is useful to develop a multilingual illustrated μ-thesaurus of “mechanism” indexing terms. This paper proposes a complete database of multilingual illustrated mechanisms science indexing terms, which will overcome the language barrier and will be integrated into technical macro-thesauri.
E.-C. Lovasz, D. Perju, B. Corves, T. Brix, K.-H. Modler, I. Maniu, C.M. Gruescu, A. Lovasz, V. Ciupe

A General Classification for Mechanisms Regarding the Motion Task

This paper presents a general classification method for mechanisms regarding the motion task which is used for storing mechanisms in a database. This classification bases on a practical oriented concept. A motion task to be solved can be described by pre-defined characteristics in a search engine in the IGM-Mechanism encyclopaedia. Through a comparison with the saved data in the database possible mechanisms were offered as solution for the motion task. The user can choose among these possibilities to find the best mechanism.
B. Corves, S. Kurtenbach, M. Hüsing, C. Schneider

Mechatronic and Biomechanic Applications


Developments of a Knee Motion Assist Mechanism for Wearable Robot with a Non-circular Gear and Grooved Cams

For wearable robot, the active knee joint assist mechanism has been developed. Especially, this mechanism is driven by a non-circular gear and grooved cams. This mechanism rotates and slides simultaneously, which has 2 degree-of-freedom. And relation between a rotation and a sliding motion can approximate arbitrary mathematical function. And using this mechanism, the knee joint can flex until 130degrees. It is larger than the angle of a conventional joint. In this report, the motion of a knee flexion is analyzed. We propose the fundamental design method. And to move smoothly, we investigate the motion curves. And the optimized locus of a non-circular gear pitch and a grooved cam are shown. Also, the prototype knee joint assist mechanism is evaluated. It is clear that proposed mechanism is useful for the motion assist of a knee joint.
H. Terada, Y. Zhu, M. Suzuki, C. Cheng, R. Takahashi

Force Distribution for a Walking Robot with Articulated Body

Legged vehicles have attractive capabilities in terms of agility and obstacle avoidance. Also, these platforms are superior for locomotion on soft ground comparing to wheeled or tracked robots, particularly in low gravity. The functional capabilities of a walking robot can be essentially expanded by changing of the body design. It means that climbing over obstacles equal to the geometrical size of the robot could be possible by using a legged platform with articulated body. In this paper, some aspects regarding the force distribution for a hexapod walking robot with articulated body and its active compliance are presented.
I. Doroftei, Ghe Plesu, B. Stirbu

Numerical Root Finding from an Engineer’s Point of View

The article starts with a presentation of a straight-forward global root finding algorithm featuring Newton-Raphson-like local root finding to find all solutions. After an analysis of the causes why it may fail, strategies are given to improve root finding. The strategies are tested and statistically analyzed with respect to two practical mechanical engineering problems: determining the point positions of an Assur group of third order and determining the translation and orientation of a Stewart Gough platform. In conclusion, ten advices are given on how to do root finding successfully and quickly.
M. Färber, U. Döring

Kinetostatic Analysis of an Articulated Walking Mechanism

The mathematical model for kinetostatic analysis of Jansen’s type walking mechanism is presented in this paper. This mechanism will be implemented in the structure of a walking robot. Simulation results from CAD programs are also presented for validation of the mathematical model and for analyzing the 3D model of the mechanism. From a structural point of view the investigated mechanism consists in eight bar elements connected through revolute joints. The shape of the leg mechanism described is similar with the original one proposed by Theo Jansen.
F. Moldovan, V. Dolga, C. Pop

A Mirror Tracking Mechanism

Solar heliostat field use a tower and a set of mirrors spread over a precise area. The publications refer to solar energy name the mirror that tracks to the Sun as heliostat. There is yet a theory related to the heliostat tracking. Indeed, there is a set of methods of tracking control based on calculus algorithm. The paper tries to promote a mechanism that implement the reflection function to facilitate the heliostat target orientation. The mechanism should be equipped with a target line sensor. This one must target the Sun.
N.M. Dehelean, L.M. Dehelean

Choppers: Optomechatronic Devices for the Controlled Modulation of Light

We present our main contributions and current work regarding one of the most used mechatronic devices for optical applications: the choppers. The issues of the macroscopic choppers with rotating wheels are presented, with a focus on the chopping frequency and on the profile of the transmitted flux (the modulation function) generated. The profiles we have investigated theoretically for the classical chopper wheels, with linear margins, and for top hat light beam distributions are discussed. The new configuration of the “eclipse choppers” (with windows with circular margins) we have introduced to produce approximate triangular series of impulses is presented, and the modulation functions produced are characterized. An insight in the experimental part of the study we are currently working on is provided, from the prototype wheels we have manufactured to the optical setup built for the testing of the different geometrical configuration of wheels, and to the first results.
V.-F. Duma, M.F. Nicolov, M. Kiss, T. Ilca, C. Mnerie, D. Demian, L. Szantho

Motion Laws of a Varifocal Objective Working with a 1/2” CCD Camera

Varifocal objectives for imaging systems integrating CCD sensors are useful in numerous applications, but there are no standards to design such systems. The present paper proposes a varifocal objective, suited for a 1/2” CCD camera, working at constant distance between the object plane and the image plane and providing a variable magnification within the range of (0.33…0.68). The motion laws of the mid, negative lens, respectively the last, positive lens are calculated. The optical system is diffraction limited over the entire range.
C.M. Gruescu

Mechanisms and Machine Design


A New Principle of Adaptive Compliant Gripper

Gripping and holding of objects are key tasks for robotic manipulators. The development of universal grippers able to pick up unfamiliar objects of widely varying shapes and surfaces is a very challenging task. This paper presents an approach of the new principle of a universal gripper with adaptable shape morphing surfaces. The adaptive surfaces will have the controllability by a compliant system with embedded actuators and sensors. The main sensing system has to be made of a conductive silicone rubber or foam. These are carbon-black filled silicone materials with good sensing properties whose electrical resistance is changed by compression. The implemented controllable system will be able to morph shapes of the gripper to accommodate different objects. A methodology for design of the compliant adaptive gripper will be presented. The main advantage of this compliant gripper is the connection of controllability and observability in one system by a compliant mechanism.
D. Petković, N.D. Pavlović

Optimum Design of Cam Mechanisms

The paper presents some considerations about the optimum design of cam mechanisms with reciprocal and oscillating roller followers. The objective function express the dimension of the cam, while the constraints limit the size of the pressure angle and / or the magnitude of the unit stress to the higher contact between cam and follower or cam and roller. Finally, the result of solving a numerical example is presented.
I. Simionescu, M. Ene, L. Ciupitu

Linkage Solutions for the Manufacture of Complex, Thermoplastic Lightweight Structures

The manufacturing of novel, high-performance fibre composite components based on hybrid yarns necessitates the development of new process solutions. In the particular case of manufacturing open core sandwich panels, tools are required which facilitate automated manufacturing. Such automation can be achieved using specially adapted wedge kinematics, which in turn require handling systems that ensure a correct position of these tools. One mainpart of such handling system is a comb system, which is successfully approved by the manufacturing of planar sandwich panels. Single-bend sandwich panels requires the development of new solutions, which facilitate the oriantation of the consolidation tools with a minimum of drive effort. Thereby the focus is on the design of a comb system based an a scissor mechanism.
M. Krahl, U. Hanke, K.-H. Modler

RBS Simulation of Integrated Piezo-Ceramic Actuation for Textile Reinforced Composite Compliant Mechanisms

Structure-integrated drives use compliant elements to transmit motion just by structural deformations, and also, integrate piezo-ceramic actuators into the composite’s laminate lay-up to command and control the motion. The transmission of motion sequences can be obtained with reduced number of parts and low structural weight. However, the actual motion of the system can be obtained with the desired accuracy only after tests and re-design. Thus, reliable procedures able to predict the actual motion of compliant mechanisms with integrated actuators are necessary. This paper makes a contribution to the compliant structure simulation by developing a RBS method to obtain the piezo-ceramic actuation simulation for bending actuators using kinematical simulation models with single layer and double layer actuating cells.
N. Modler, K.-H. Modler, W. Hufenbach, D. Margineanu, E.-C. Lovasz, D. Perju, Ev. Ianosi

Computational and Experimental Methods and Dynamics of Mechanisms and Machines


Maximally Regular Planar Non Fully Parallel Manipulators

This paper presents a new family of maximally regular planar non fully parallel manipulators (PPMs). The moving platform has three planar degrees of freedom, which are two planar translations and one rotation around an axis perpendicular to the plane of translations. A one-to-one correspondence exists between the actuated joint velocity space and the external velocity space of the moving platform. The Jacobian matrix mapping the two vector spaces of the maximally regular PPMs is a 3×3 identity matrix throughout the entire workspace. The condition number and the determinant of the Jacobian matrix being equal to one, the maximally regular parallel robots perform very well with regard to force and motion transmission capabilities. The new kinematic criteria, used for structural synthesis, are based on the recent formulae proposed by the author for mobility, connectivity, redundancy and overconstraint of parallel robots. These kinematic criteria allow us to get new families of over constrained and non overconstrained maximally regular parallel robots with planar motion of the moving platform. The non fully-parallel solutions are presented for the first time in the literature.
G. Gogu

An Experimental Characterization of a Rickshaw Prototype

In this paper, a rickshaw robot has been characterized from aspects of mechanical design and experimental tests. Experiments have been done to measure the contact forces between the feet and terrain, acceleration of the robot body, and torque of the motor during a walking process. Experimental results of walking operation of a built prototype have been reported to show characteristic features of a rickshaw efficient performance.
T. Li, M. Ceccarelli

Considerations upon the Influence of Manufacturing and Assembly Errors on the Kinematic and Dynamic Behavior in a Flight Simulator Stewart-Gough Platform

The paper presents a new approach concerning the accuracy of a dynamic flight simulator behavior by considering the influence of the manufacturing and assembling errors on the kinematics and dynamics of a Stewart-Gough platform. The obtained models offer the possibility of a complex study of the parallel structure in order to evaluate the kinematic and dynamic behaviors and to generate the control algorithms for an appropriate digital immersion. Using a numerical simulation the diagrams due to the manufacturing errors are computed and represented.
A. Pisla, T. Itul, D. Pisla, A. Szilaghyi

Characterization of Flexure Hinges Usingthe Script Oriented Programming Withina FEM Software Application

Using the script oriented programming within a software application based on the finite element method, it is possible to simulate the behaviour of a large number of different flexure hinges making a minor modelling effort. After creating a program, the stiffness / compliance and motion characteristics are determined and analyzed for circular and elliptical flexure hinges in this paper.
I. Ivanov, B. Corves

Basic Result on Type II DM Self-Motions of Planar Stewart Gough Platforms

In a recent publication [10] the author showed that self-motions of general planar Stewart Gough platforms can be classified into two so-called Darboux Mannheim (DM) types (I and II). Moreover, in [10] the author was able to compute the set of equations yielding a type II DM self-motion explicitly. Based on these equations we present a basic result for this class of self-motions.
G. Nawratil

Active Bearing for Vibration Damping of Roller Systems with Piezoelectric Actuators

To improve the efficiency of printing or coating processes for paper products the velocity of the web and the roller width can be increased. However, these measures cause deformations of the rollers, heating effects and streak print defects due to undesirable oscillations. The vibration characteristic is significant for the quality and efficiency of the printing or coating processes. Approved methods like balancing of the rollers and maximizing the bending stiffness have come to technical limits. This seems to be promising technology for further optimization of printing and coating machines. This paper describes an approach with piezoelectric actuators in a flexographic printing machine by introducing active elements in the bearings of a roller to compensate undesired bending vibrations. Similar active components for vibration damping have been introduced successfully in grinding and milling machines [1, 2].
M. -C. Voicu, R. Schmidt, B. Lammen, M. Mersch, I. Maniu

On the Kinematics of a Hybrid Parallel Robot Used in Minimally Invasive Surgery

The paper presents some aspects about the kinematics of a hybrid parallel robot used in minimally invasive surgery: PARASURG 9 M. The robotic structure PARASURG 9 M consists of two modules: a hybrid parallel robotic arm with five DOF - PARASURG 5 M, and a parallel robotic surgical instrument PARASIM with four DOF. After a short introduction in the approached field, the hybrid parallel structure PARASURG 9 M is presented. Using the developed geometrical models, some numerical results of PARASURG 9 M are presented.
M. Suciu, B. Gherman, C. Vaida, N. Plitea, A. Stoica, D. Pisla

Mechanical Transmissions


Synthesis of Toothed Continuously Variable Transmission (CVT)

Continuously variable transmission contains the closed gear differential and the controlled device. It is proved that closed gear differential in itself carry out a function of a controlling device. The elementary gear (toothed) continuously variable transmission has form of the gear closed differential with two degrees of freedom. The gear differential with the closed contour of toothed wheels creates additional constraint and supports a transition regime of motion from a start-up to bi-mobile regime with independent stepless regulating. The equations of interconnection of power, kinematic and geometrical parameters of transmission in statics, kinematics and dynamics are searched out. The synthesis of transmission consists in determination of teeth wheels numbers on a condition of overcoming the given maximum moment of resistance. The design of the gear regulated transmission is presented. Design of gear continuously variable transmission is presented. The found regularities allow synthesizing gear continuously variable transmission with constant engagement of toothed wheels on the given operational parameters of motion.
K. S. Ivanov

Differential Planetary Gear Transmissions Usable in Renewable Energy Systems

Many of the renewable energy systems (RES) use planetary gears for the speed increase or reduction. The paper presents a 2 DOF planetary gear transmission to be used as “speed increaser” in the counter-rotating wind turbines, hydropower plants, and, also as “speed reducer”, in the tracking systems that equip the solar photovoltaic or solar thermal systems. The transmission modelling, simulation and examples of applications in the field of renewable energy systems is presented in the paper.
R. Saulescu, C. Jaliu, D. Ciobanu, D. Diaconescu

Loading Devices for Closed-Loop Gear Test Stands

The paper deals with the problem of test stands for gears. The most convenient solution to test or brake in gear transmissions is the closed-loop stand. Its general features and basic assemblies are described. The paper develops the design of the loading coupling and presents constructive solutions manufactured and tested in laboratory. The loading device itself is a complex assembly which simulates the external loading in functioning. Mathematical approach and constructive elements are presented for a loading device based on a scheme of a quasi-differential mechanism. Also, three solutions for automated control of progressive loading are developed to work together with the quasi-differential.
C. M. Gruescu, I. Nicoara, E. Busa


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