K.-H. Modler

Geometrical Synthesis Approach for Compliant Mechanisms – Design of Applications Exploiting Fibre Reinforced Material Characteristics

Compliant mechanisms have several advantages, especially smaller number of elements and therefore less movable joints. The flexural members furthermore allow an integration of special functions like balancing or locking. To take advantage of compliant elements in applications a robust synthesis tool is needed.Most of the common synthesis methods focus on energy storage or shape optimization. The purely geometrical approach presented in this paper concentrates on solving guidance tasks with maximum design freedom within the installation space. An easy to use step-by-step synthesis procedure is provided through which the user is able to design mechanisms with a compliant beam element. The necessary analysis of the compliant beam element can be done by numerical analysis as well as through experiments. The synthesis method is presented using an application for a cup holder mechanism made of fibre reinforced material.

Cam Mechanism with Flat/Tangential Translating Follower and Its Size

An important problem in the cam mechanisms synthesis is their total size as a minimization condition (criteria). Usual this condition is reduced to the cam size only, which may be partial accepted for cam mechanisms with oscillating follower ([1], [3], [4], [5]). The problem is quite different when the cam mechanism has a translating follower. In this case the length of follower’s guiding is a very important contributor to the total size of the cam mechanism. This problem was presented in [2] for cam mechanisms with contact roll of the translating follower. The same problem will be presented in this paper but for cam mechanism with flat translating follower.

Experimental Design and Control Approach of an Active Knee Prosthesis with Geared Linkage

The main purpose of this paper is to develop a novel experimental design of knee prosthesis for trans-femoral amputees, which uses a geared linkage in order to generate a rotational movement of the knee joint. The geared linkage with linear actuator can reproduce an approximately linear transmission function for a very large rotation angle. This property of the geared linkage allows an easier control of the walking gait. Such prosthesis becomes active by empowering it with an electro-pneumatic circuit and an electro-pneumatic control unit, which allows the control of the swing phase.

Numerical Method for Determination of Base Circle Radius of Cam Mechanisms with Oscillating Flat-Face Follower

The paper proposes an original numerical method for computation of the base circle radius of the cam mechanism with oscillating flat-face follower. The base circle radius is a parameter in order to optimise the design of the cam profile. The synthesized cam profile should be continuously convex without inflection or singularity points. The numerical method uses the conditions to avoid the singularities and to achieve a strictly positive curvature radius.

Kinematic Analysis of a Belt Mechanism with a Circular Eccentric Output Element

The paper proposes two methods for kinematic analysis of a belt mechanism with circular eccentric output element (link). One of them is based on the mechanisms geometry and the second on its kinematics in order to obtain the transmission functions of different order. Both approaches are based on a imaginary cam mechanism instantaneous isokinetic with the given belt mechanism. The transmission functions obtained by means of proposed procedures are in a numerical form due to the finite incremental method used in solving the problem.

Umlauffähigkeit räumlicher mechanismen

Zusammenfassung Fur 4-gliedrige ebene, spharische und raumliche Mechanismen, deren Ubertragungsgleichungen die gleiche Struktur haben, wird eine gemeinsame Theorie der Umlauffahigkeit gegeben: Die Ubertragungsgleichung muβ die Interpretation als algebraische Korrespondenz vom Typ (1, 2) zwischen zwei Kegelschnitten gestatten. Dazu wird die Theorie der Kegelschnittbuschel benotigt, die eine vollstandige Klassifizierung dieser Getriebe begrundet: Die Realitat der Buschelpunkte und die Art der Kegelschnitte geben Aaukunft uber Umlauffahigkeit und Art des Getriebes. Die Bedingungen fur die Umlauffahigkeit werden unabhangig vom Getriebetyp angegeben.

On the Kinematic Analysis of a Sixth Class Mechanism

The paper deals with the kinematic analysis of a particular case of a “multiple-bar mechanism” from Artobolevsky’s mechanisms collection. The structural analysis of this eight-link mechanism shows that it is a six class third order mechanism according to Assur-Artobolevsky classification. The kinematic analysis of such a mechanism is very difficult through the direct method. Usually, the kinematic analysis is performed by means of reducing the mechanism’s class through the swapping of the input and output links. The paper proposes another method to reduce the class of a mechanism, namely by choosing a certain moving link as referential and studying the relative movements of the remaining links/elements. Thus, the transmission function can be found, as a function of the original input and output links. Such a mechanism is useful for manufacturing of compound light structures.

Path Generating Belt Mechanisms as Kinematic Chains for Mechatronic Applications

The paper deals with a special type of planar belt mechanism with two degrees of freedom. Belt mechanisms achieve in principle any movement task, precisely, in a defined range, by using a belt as a flexible and inextensible element and at least one profiled wheel (non-circular wheel), on which the belt is enveloped or developed. In order to use belt mechanisms in mechatronic applications, the increasing of the degree of freedom and the use of simple circular wheel are required. The control of the actuator’s movement makes theoretically possible the generation of any movement task in the wheel’s plane.

Steering and Non-steering Crawling Tetrahedral Micro-mechanisms

Crawling mechanical structures with energetic autonomy and remote control may move and steer by sliding on the ground. The paper presents a study on simple possibilities to achieve sliding movement with a crawling tetrahedral structure and studies their movement capabilities both analytically and by MBS simulation. The structures are analyzed using an equivalent plane model and a 3d model, respectively. The analysis is structural, kinematical, static and dynamic.

Numerical Iterative Method for Computing the Base Circle Radius of Cam Mechanisms with Translating Flat-Face Follower

The paper proposes a numerical method for computation of the base circle radius of cam mechanisms with translating flat-face follower as alternative to the traditional graphic-analytical method. The base circle radius is a very important data in the synthesis of the cam profile. The method uses two conditions: to keep the curvature continuously positive in all points along the cam profile and to avoid inflection or singularity points.