Tobias Kaufhold

Compliant Multistable Tensegrity Structures with Simple Topologies

This paper describes a method to identify compliant tensegrity structures with multiple states of self-equilibrium. The considered algorithm is based on the repeated use of a form-finding procedure, using the static Finite-Element-Method. The algorithm can be used to develop compliant multistable tensegrity mechanisms with simple topologies. Therefore three planar tensegrity mechanisms with two or three stable equilibrium configurations are exemplary considered and verified experimentally.

Indoor locomotion experiments of a spherical mobile robot based on a tensegrity structure with curved compressed members

This work presents theoretical and experimental investigations on an untethered rolling tensegrity robot. Previous research has shown, that rolling locomotion of compliant tensegrity robots can be realized without change of their shape, by using only internal mass shifting. The use of simple tensegrity structures, based on curved compressed members enables pure rolling locomotion in contrast to the most known prototypes of this kind. Therefore, theoretical and experimental investigations of an untethered locomotion system based on a simple tensegrity structure, consisting of two disconnected compressed curved members connected to a continuous net of twelve prestressed tensioned members with pronounced elasticity, are considered. Planar locomotion is induced by the movement of only two drive units as internal masses along the curved compressed members. Theoretical considerations show the influence of the geometrical system parameters on the movement behavior of the system. With the help of experimental investigations, by using motion-capturing technique, main properties of the locomotion performance of a prototype are discussed.

Spherical mobile robot based on a tensegrity structure with curved compressed members

The use of mechanically compliant tensegrity structures in mobile robots is an attractive research topic. This paper describes a new concept for rolling locomotion of mobile robots based on tensegrity structures. In particular, an untethered locomotion system based on a simple tensegrity structure, consisting of two rigid disconnected compressed curved members connected to a continuous net of twelve prestressed tensioned members with pronounced elasticity, is considered. The locomotion is induced by the movement of two internal masses. The working principle of the system is discussed with the help of kinematic considerations and verified with experimental tests.

Theoretical and Experimental Investigations of Amoeboid Movement and First Steps of Technical Realisation

We report about the investigation of the amoeboid locomotion at Amoeba proteus. Based on the detailed experimental study of the internal cytoplasm flow and the variation of the contour of the amoeba with optical flow measurement techniques like particle image velocimetry (PIV) we found characteristic velocity fields and motions of the center of mass. Furthermore a peripheral cell model is developed, in which a contractile backward flow of actin-myosin in the cortex stabilizes cell polarity and locomotion by inducing more protrusions in the front and stronger retraction in the rear. The results from the experimental and theoretical study were used to realise prototypes of locomotion systems, composed of silicon elastomer body with controlled elasticity and driven by a magnetic system, based on amoeboid motion principles.