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Über dieses Buch

This book brings together investigations which combine theoretical and experimental results related to such systems as capsule micromechanisms, active micro catheters, nanotube vascular stents, mechanisms for micromilling, different compliant mechanisms including grippers and compliant systems with actuators and sensors, microrobots based on vibrations, tactile sensors, tooth brackets, compliant valves, and space reflectors.

This volume contains twenty-two contributions from researchers from ten countries, represented at the 4th Conference on Microactuators and Micromechanisms, which was held in 2016 in Ilmenau, Germany. The aim of the conference was to provide a special opportunity for a know-how exchange and collaboration in various disciplines concerning systems pertaining to micro-technology.

This Conference was organized under the patronage of IFToMM (International Federation for the Promotion of Mechanism and Machine Science).



Study on Polymer-Made 3DOF Spatial Parallel Manipulator

In this research, in order to realize the functions equivalent to the functions of the spherical bearing which is frequently used in conventional spatial mechanisms, a polymeric manufactured hinge with Hytrel ® (DUPONT Co., Ltd.), which has excellent flexural fatigue resistance, have been proposed. Next, the shape and dimensions of the polymeric manufactured hinge having low stress values at bending deformation have been found by FEM analysis results. In addition, a polymer-made three-degrees-of-freedom(3DOF) spatial parallel manipulator which consists of this polymer-made hinge is designed and developed, and the output displacement characteristics of the manipulator are revealed.
M. Horie

Miniaturization of Check Valves

This contribution deals with principles of developing and constructing technologies to enable the optimization of hydraulic components. The focus is on conventional check valves with a goal of achieving a reduction in size and an accompanying optimization of the housing. For this purpose, check valves, which up to now have had to be installed as additional equipment, are first analyzed, the requirements determined and then redesigned. Here, a conventional rigid-body valve is replaced by a compliant model, creating a monolithic component and uniting the functions of multiple elements, such as springs and closing members (steel balls). The model based development of the novel valve system was carried out by Finite Element Method (FEM). The new valve was improved, in relation to weight and design space, compared to the ball check valve.
M. Pendzialek, J. Schneider, K. Höhe, L. Zentner

A Biologically Inspired Sensor Mechanism for Amplification of Tactile Signals Based on Parametric Resonance

In this paper, the vibrational motion of an elastic beam under the parametric excitation is investigated theoretically and numerically. The problem is motivated by biological tactile sensors, called vibrissae or whiskers. Mammals use these thin long hairs for exploration of the surrounding area, object localization and texture discrimination. We propose a mechanical model of the vibrissa sweeping across a rough surface as a straight truncated beam stimulated by a periodic following force. The equation of transverse motion of the beam is studied using the Euler–Bernoulli beam theory and asymptotic methods of mechanics. The numerical analysis is performed by means of the finite element method. It is shown that the parametric resonance of the beam occurs at the specific ranges of the excitation frequency, which depend on the parameters of the beam and the amplitude of the applied force. For these frequency values, the vibrations of the beam are unstable with exponentially increasing amplitude. The comparison of the resonance ranges obtained theoretically and numerically is made. Thus, together with the realisation of the viscoelastic support of an artificial tactile sensor, the parametric resonance may be a potentially useful method for amplifying small signals arising from the contact with an object.
T. Volkova, I. Zeidis, K. Zimmermann

Towards the Development of Tactile Sensors for Determination of Static Friction Coefficient to Surfaces

Natural vibrissae fulfill a lot of functions. Next to object distance detection and object shape recognition, the surface texture can be determined. Inspired by the natural process of surface texture detection, the goal is to adapt this feature by technical concepts. Modeling the vibrissa as an Euler–Bernoulli bending beam with a quasi-statically moving support and the vibrissa–surface contact with respect to Coulomb’s Law of Friction, a first approach was formed by the group of Behn and Steigenberger. Due to the motion of the support (pushing the vibrissa) and the surface contact, the vibrissa gets deformed. Firstly, the beam tip is sticking to the surface. The acting friction force prevents a movement of the beam tip until the maximal stiction is reached. The displacement of the support corresponds to changes in the acting forces and moments. Out of these changes the coefficient of static friction can be determined. The analytical results of Steigenberger and Behn are verified and validated by numerical simulations and an experiment.
M. Scharff, M. Darnieder, J. Steigenberger, C. Behn

Development and Investigation of Photoelastic Sensor for Torque Measurement

This article describes the development and the calibration of the photoelastic contactless torque sensor and it also presents the measurement of the starting torque of a disk micro motor, as a function of the rotor angle. Finite element analysis was performed to prove the functionality of the sensor and to determine its required sizes. In order to define the torque—rotor angle characteristics of the micro motor, electromagnetic simulation was also performed and the results were compared to each other.
A. Bojtos, N. Szakály, A. Huba

Flexural Body for a Wireless Force/Displacement Sensor

This paper deals with the design of the flexural body for a two axis force/displacement sensor based on electro-magnetic sensing principle. The compact elastic structure consists of two independent parallelograms that provide decoupled flexural motions of sensing elements in two rectangular directions. The procedure proceeds by experimental verification of this new sensing principle for building sensors that exhibit specific functional features.
J. Hricko, S. Havlik

Capsule Micromechanism Driven by Impulse—Wireless Implementation

We have developed a traveling small capsule, which has a smooth outer surface and is driven by vibration. Measuring only 11 mm in diameter and 25 mm in length, it is sufficiently small to be placed in the human gullet or intestines. Although the capsule does not have wheels nor legs, it can travel utilizing vibration. For these reasons, there is nothing protruding to harm the soft tissue of intestine. The capsule contains a small magnet, a coil, batteries and a circuit, and an electric pulse drives the coil to move the capsule. We did the experimental investigation that our capsule can travel in a plastic pipe and it can also travel on pig intestine surface. We also have developed liquid medicine dispenser that can be put inside the capsule. Our capsule may be useful for medical treatments such as inspection and drug delivery.
T. Ito, S. Murakami

Development of Peristaltically Propelled Active Catheter Used in Radial Artery

In our previous studies, many experiments using pseudoblood vessels with an inner diameter of ≤6 mm have been carried out assuming that the catheter is inserted in a femoral artery. In recent years in Japan, however, along with the trends of reducing the burden on patients and the downsizing of catheters, in more than half of the cases, catheters are inserted in radial arteries with inner diameters of 2.0–3.5 mm for the treatment of dysfunctional coronary arteries. The purpose of this study was to develop a small active catheter so that the catheter can navigate in a radial artery. The effectiveness of the catheter was confirmed by the driving experiment using silicon tubes with inner diameters of 2.5–3.0 mm and an endovascular surgery simulator.
Y. Nakazato, K. Kawanaka, K. Takita, M. Higuchi

Locomotion Principles for Microrobots Based on Vibrations

Microrobotics is a growing field with great advances in recent years. New applications in the fields of medicine, biology, manufacturing and maintenance technologies are developed. They require mobile systems with enhanced motion abilities. The present paper concerns principles of terrestrial locomotion for vibration-driven microrobots. Such systems are characterized by an internal periodic excitation, which is transformed to a directed motion due to asymmetric system properties. An extensive overview on the state of the art shows the great potential of the vibration-driven locomotion for miniaturized applications in technics. To perform a controllable two-dimensional locomotion with only one actuator, it is needed to overcome limits of rigid body systems. The proposed approach uses the frequency-dependent vibration behavior of elastic systems, like beams and plates. Experimental investigations are supported by finite element method. It is shown that the two-dimensional locomotion on a flat and solid ground can be controlled by only one actuator using the resonance characteristics of elastic systems.
F. Becker, V. Lysenko, V. T. Minchenya, O. Kunze, K. Zimmermann

Exploration of Carbon-Filled Carbon Nanotube Vascular Stents

The purpose of this research was to design, fabricate, and test coronary stent designs composed of carbon-infiltrated carbon nanotubes (CI-CNTs). Coronary stents currently have two major complications: restenosis and thrombosis. CI-CNT stents may provide improved clinical outcomes for both of these issues. Multiple stent design concepts were generated, evaluated, and two stent designs were selected: one with a semi-auxetic nature, and one designed for maximum force. These designs were further developed and optimized using analytical tools along with finite element analysis. Planar versions of the stent designs were manufactured and mechanically tested to verify performance. The performance of the cylindrical stent configurations was analyzed using finite element modeling. A sample cylindrical stent was also fabricated. This research demonstrates that feasible coronary stent designs can be manufactured from CI-CNTs. However, a major challenge for CI-CNT stent designs is meeting the design requirement of sufficient radial force.
Darrell J. Skousen, Kristopher N. Jones, Takami Kowalski, Anton E. Bowden, Brian D. Jensen

A Novel Gripper Based on a Compliant Multistable Tensegrity Mechanism

Within this paper a novel gripper is introduced. The gripper is based on a tensegrity mechanism with multiple states of self-equilibrium. These tensegrity mechanism is built upon a mechanical compliant tensegrity structure, consisting of tensile and compressive members. The existence, shape and stability of the different states of self-equilibrium depend on the parameters of the members. After investigating this dependency with a form-finding algorithm the structure is extended with additional members to obtain a two-finger-gripper. The equilibrium configurations represent the opened and the closed state of the gripper. Due to the several equilibrium configurations, the control of the gripper can be realised easily and is discussed with theoretical analyses. The working principle of the gripper and the mechanical compliance is verified by a prototype. In addition, as an outlook for further works, a miniaturised prototype of the tensegrity mechanism with two stable states of self-equilibrium has been built.
S. Sumi, V. Böhm, F. Schale, R. Roeder, A. Karguth, K. Zimmermann

Selection of the Optimal Rigid-Body Counterpart Mechanism in the Compliant Mechanism Synthesis Procedure

The main problems appearing in the compliant mechanism synthesis procedure are the realization of the accuracy of the pre-defined function as best as possible, as well as the realization of the motion range of the mechanism as large as possible. One of the most frequent compliant mechanism synthesis procedure is to develop the compliant mechanism on the basis of the rigid-body linkage being able to realize pre-defined function of the compliant mechanism. There are many advantages of using the compliant joints in the mechanism structure. On the other hand, the mechanisms with compliant joints can realize relatively small motion range, that is, their mobility is limited. Another limitation to their use is fatigue failure at the compliant joints. In each particular compliant joint the angular deflection of a flexure hinge is limited in depending of the contour and hinge dimensions as well as the type of the material being used for the production of the compliant mechanism. Therefore, if there are several rigid-body counterparts to be used in compliant mechanism synthesis procedure, it should be necessary to choose the particular rigid-body counterpart with the smallest values of the angular deflection of the compliant joints. This approach will be presented in the synthesis procedure of the compliant mechanism for rectilinear guiding.
N. T. Pavlović, N. D. Pavlović, M. Milošević

Design and Experimental Characterization of a Flexure Hinge-Based Parallel Four-Bar Mechanism for Precision Guides

This paper presents the investigation of the influence of the flexure hinge contour in compliant linkage mechanisms for precision engineering applications. Especially the influence on the precision of the path of motion and the stroke of the compliant mechanism is reflected. Based on previous results on optimized single polynomial flexure hinges, the validity of proposed guidelines is analyzed for a combination of several flexure hinges in one compliant mechanism. A parallel crank mechanism is used as an example for a compliant rectilinear guiding mechanism with constant link orientation. The parameters of the approximated linear motion are investigated for the rigid-body model, a compliant analytic model and a FEM model. Finally these results are compared with measurement results taken at manufactured prototypes.
P. Gräser, S. Linß, L. Zentner, R. Theska

Dynamic Model of a Compliant 3PRS Parallel Mechanism for Micromilling

The objective of this work is to develop a manipulator of 5 degrees of freedom for micromilling. It consists of a XY stage under a 3PRS compliant parallel mechanism, obtaining the advantages of the compliant joints as are higher repetitiveness, smoother motion and a higher bandwidth, due to the high precision demanded from the process, under 0.1 μm. In this work, the dynamics of the compliant stage will be developed. The modelling approach is based on the use of the Principle of Energy Equivalence combined with the Boltzmann-Hamel equations to analyze the rotational dynamics of the platform. A pseudo-rigid model has been assumed for the compliant joints, calculating the flexural and torsional stiffness by FEA. Finally, a prototype has been built and some preliminary results are shown comparing the simulation and the measurements.
A. Ruiz, F. J. Campa, C. Roldán-Paraponiaris, O. Altuzarra

Dynamic Analysis of a Fatigue Test Bench for High Precision Flexure Hinges

General technological development and better knowledge of compliant mechanisms increase the growth in their applications. In current science the focus is on developing new hinge shapes or improving existing hinge types. Even though it can be assumed that the manufacturing based influences have a crucial impact on the performance of flexure hinges, experimental studies of the fatigue of compliant joints are currently missing in research activities. Thus, a test bench for fatigue testing was built to study the manufacturing based influences on the performance of high precision flexure hinges. First investigations show high load cycles. Hence it might be useful to increase the test frequency to reduce the overall testing time. Nevertheless, this causes increased inertia forces and moments which could additionally affect the test specimens. Accordingly, this contribution analyzed the dynamic behavior of the test bench. The kinematic equations are derived. Afterwards the actual forces acting on the test specimens are calculated and compared to a quasi-static load.
D. Schoenen, M. Hüsing, B. Corves

Self-setting Locks for Petal Type Deployable Space Reflector

The new design of petal type deployable space antenna is presented. To improve important characteristics of reflector—deployment repeatability, reflecting surfaces accuracy, rigidity and effective area of open mirror—the new kinematic scheme of petal mirror deployment is proposed. Within developed approach the deployment of large mirror is fulfilled in two stages. During the first stage the structure is transformed with low accuracy from folded position into a state close to the working one. High precision fixing of open mirror is performed during second stage of deployment. Self-setting locks are introduced into the structure and used for micromanipulations with the petals during second stage of mirror opening. The new kinematic scheme of deployment and the design of the locks are described. At the final stage of the reflectors deployment the self-setting locks operate as compliant mechanisms.
V. I. Bujakas, A. A. Kamensky

Monolithic and Statically Balanced Rotational Power Transmission Coupling for Parallel Axes

A new fully compliant rotational power transmission mechanism is presented. The design is based on the Pseudo-Rigid-Body Model (PRBM) of the Oldham constant velocity coupling. It can be fabricated as a single piece device with planar materials which make it suitable for micro scale applications. The internal stiffness of the proposed structure is eliminated by static balancing technique. Therefore, the compliance and zero stiffness behavior compensate for the structural error and poor efficiency inherent in rigid-body Oldham coupling, resulting in high mechanical efficiency power transmission system. The device is designed and its motion, torsional stiffness, and torque-angular displacement relations are predicted by the PRBM and finite element modeling. A large/macro scale prototype was manufactured and measured to evaluate the concept. This high efficient power transmission system can be applied in different applications in precision engineering and the relevant field such as micro power transmission system.
D. Farhadi Machekposhti, N. Tolou, J. L. Herder

Investigation of the Novelty Brackets “Gold-S”

The paper presents the new alternative orthodontic bracket Gold-S. The current applied force of wire on the compliant mechanism and thus its stiffness, will be determined and decreased. Furthermore, the investigation aims on decreasing stiffness by 25 %. Firstly, the geometric CAD model is simulated using the Finite Element Method (FEM), specific parameters are then altered. Accordingly boundary conditions, assumed simplifications and meshing is explained. Secondly, an experimental investigation is conducted, using an additive 3D printing process for the original as well as the improved model. Finally, the occurring forces in both models of the compliant mechanism are displayed in a graph for comparison of simulation and experimental investigation. It turns out that both results are quite similar, even though friction problems were encountered during investigation due to the used model material.
F. Pollok, C. von Mandach, S. Griebel, V. Böhm, L. Zentner

Dynamic Behavior of Active Lightweight Compliant Mechanisms with Integrated Piezoceramic Actuators by Under- and Overcritical Periodic Excitation

Integration of active elements as thermoplastic-compatible piezoceramic modules in lightweight compliant mechanisms offers the possibility to actively control its structural behavior by static, dynamic or vibro-acoustic loads. New active lightweight structures with material-integrated structural monitoring, energy-harvesting, or active vibration damping functionalities become possible. Previously, a demonstrator mechanism was designed and built, and its behavior under quasi-static excitation was simulated as a multi-body system, using two-layer cells with torsion and traction springs for compliance and linear motors for excitation. The mechanism was later tested to confirm the simulation results. This paper presents a study of the dynamic behavior of active compliant mechanisms obtained by integration of piezoceramic actuators into fiber-reinforced composite structures. The results of the dynamic mechanical simulation procedure were compared with experimental results for a given demonstrator mechanism. The comparison concluded that the simulation procedure describes fairly accurate the real behavior of the lightweight compliant mechanism, thus it can be used in the development of new active structures.
N. Modler, A. Winkler, A. Filippatos, Erwin-Christian Lovasz, D.-T. Mărgineanu

Synthesis of Compliant Mechanisms With Defined Kinematics

A mechanism is designed to transform forces and/or displacements from an input to one or multiple outputs. This transformation is essentially ruled by the kinematics, i.e. the defined ratio between input and output displacements. Although the kinematics forms the basis for the design of conventional mechanisms, some common approaches for the topology and shape optimization of compliant mechanisms do not explicitly include the kinematics in their optimization formulation. The kinematics is more or less an outcome of the optimization process. A defined kinematics can only be realized by iteratively adjusting process-specific optimization parameters within the optimization formulation. This paper presents an optimization formulation that solves the aforementioned problem. It bases on one of the authors former publications on the design of compliant mechanisms with selective compliance. The formulation is derived by means of an intensive workup of the design problem of compliant mechanisms. The method is validated for a common design example: a force inverter.
A. Hasse, M. Franz, K. Mauser

A Concept of Adaptive Two Finger Gripper with Embedded Actuators

Today in many industries there is a great need for grasping different shaped and soft objects. For safe grasping of such objects and specially a fragile one adaptability is required. Developing a gripper that can adapt the shape of its grasping surface to different shaped objects and achieve safe and reliable manipulations of that objects, represent a challenging task. Many micro domain applications would benefit from adaptive gripper and adaptive grasping, such as in medicine or biomedicine where there is a need for manipulations of human tissue or individual cells. This paper presents concept of a new adaptive two finger gripper with embedded actuators. By using compliant systems—compliant mechanisms with embedded actuators it is possible to develop an adaptive compliant gripper. By embedding the actuators gripper could morph or change the shape of its grasping surface and achieve different grasping patterns i.e. gripper would have structural adaptability. Synthesis methodology for the adaptive gripper that includes simultaneous topology optimization and actuators placement, is also presented. It will be shown that the developed adaptive gripper can achieve multiple shapes of its grasping surface when different contracting or extending actuators are active, whereby they realize different stroke.
A. Milojević, N. D. Pavlović, S. Linß, M. Tomić, N. T. Pavlović, H. Handroos

Implementation of Self Contact in Path Generating Compliant Mechanisms

Path generating compliant mechanisms with self contact are synthesized using continuum discretization and negative circular masks. Hexagonal cells are employed to represent the design space and negative circular masks are used to remove material beneath them. Each mask is defined by three parameters which constitute the design vector, which is mutated using the Hill-climber search. Hexagonal cells circumvent various geometrical singularities related to single point connections however, many “V” notches get retained on the boundary edges. Self contact is permitted between various subregions of the continuum. To achieve convergence in contact analysis, it is essential to have smooth boundary surfaces for which a smoothing technique is employed. Consequently, many hexagonal cells get modified to six-noded generic polygons. Non-linear finite elements analysis is implemented with Mean Value Coordinates based shape functions. Self contact is modeled between two deformable bodies in association with augmented Lagrange multiplier method. To minimize the error in shape, size and orientation between the actual and specified paths, a Fourier Shape Descriptors based objective is employed. An example of path generating compliant mechanism which experiences self contact is presented and its performance is compared with a commercial software.
Prabhat Kumar, Anupam Saxena, Roger A. Sauer

Erratum to: Dynamic Analysis of a Fatigue Test Bench for High Precision Flexure Hinges

Without Abstract
D. Schoenen, M. Hüsing, B. Corves
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