TY - CHAP A1 - Böhm, Valter A1 - Schorr, Philipp A1 - Schale, Florian A1 - Kaufhold, Tobias A1 - Zentner, Lena A1 - Zimmermann, Klaus T1 - Worm-Like Mobile Robot Based on a Tensegrity Structure T2 - 2021 IEEE 4th International Conference on Soft Robotics (RoboSoft): 2.04.2021 - 16.04.2021, New Haven, CT, USA N2 - This work presents a novel concept to develop mobile robots enabling crawling locomotion in tubular environment. Chain-like systems are designed by serial cascading a uniform tensegrity module. Inspired by the movement of worms in nature, an undulating shape change of the system is targeted to generate locomotion. The shape changeability of an exemplary tensegrity module due to internal actuation is examined in simulations and experiments. A prototype consisting of these tensegrity modules is manufactured and the locomotion principle is verified in experiments. Comparing to existing prototypes this approach enables an enhanced compliance due to the modular assembly of tensegrity structures. KW - Mobile robots KW - motion control Y1 - 2021 SN - 978-1-7281-7713-7 U6 - https://doi.org/10.1109/robosoft51838.2021.9479193 SP - 358 EP - 363 PB - IEEE ER - TY - JOUR A1 - Chavez, Jhohan A1 - Schorr, Philipp A1 - Kaufhold, Tobias A1 - Zentner, Lena A1 - Zimmermann, Klaus A1 - Böhm, Valter T1 - Influence of Elastomeric Tensioned Members on the Characteristics of Compliant Tensegrity Structures in Soft Robotic Applications JF - Procedia Manufacturing N2 - The use of mechanically prestressed compliant structures in soft robotics is a recently discussed topic. Tensegrity structures, consisting of a set of rigid disconnected compressed members connected to a continuous net of prestressed elastic tensioned members build one specific class of these structures. Robots based on these structures have manifold shape changing abilities and can adapt their mechanical properties reversibly by changing of their prestress state according to specific tasks. In the paper selected aspects on the potential use of elastomer materials in these structures are discussed with the help of theoretical analysis. Therefore, a selected basic tensegrity structure with elastomer members is investigated focusing on the stiffness and shape changing ability in dependence of the nonlinear hyperelastic behavior of the used elastomer materials. The considered structure is compared with a conventional tensegrity structure with linear elastic tensioned members. Finally, selected criterions for the advantageous use of elastomer materials in compliant tensegrity robots are discussed. KW - compliant tensegrity structures KW - soft robotics KW - elastomers Y1 - 2020 U6 - https://doi.org/10.1016/j.promfg.2020.11.048 SN - 2351-9789 VL - 52 SP - 289 EP - 294 PB - Elsevier ER - TY - CHAP A1 - Schorr, Philipp A1 - Böhm, Valter A1 - Zentner, Lena A1 - Zimmermann, Klaus T1 - Dynamical Investigation of Crawling Motion System based on a Multistable Tensegrity Structure T2 - Proceedings of the 15th International Conference on Informatics in Control, Automation and Robotics : Porto, Portugal, 29.07.2018 - 31.07.2018 N2 - The basic idea of this article is the utilization of the multistable character of a compliant tensegrity structure to control the direction of motion of a crawling motion system. A crawling motion system basing on a two-dimensional tensegrity structure with multiple stable equilibrium states is considered. This system is in contact with a horizontal plane due to gravity. For a selected harmonic actuation of the system small oscillations around the given equilibrium state of the tensegrity structure occur and the corresponding uniaxial motion of the system is evaluated. A change of the equilibrium state of the tensegrity structure yields to novel configuration of the entire system. Moreover, the motion behavior of the novel configuration is totally different although the actuation strategy is not varied. In particular, the direction of motion changes. Therefore, this approach enables a uniaxial bidirectional crawling motion with a controllable direction of motion using only one actuat or with a selected excitation frequency. Y1 - 2018 SN - 978-989-758-321-6 U6 - https://doi.org/10.5220/0006852701220130 SP - 122 EP - 130 PB - SCITEPRESS ER - TY - GEN A1 - Chavez, Jhohan A1 - Henning, S. A1 - Zentner, Lena A1 - Böhm, Valter T1 - Soft tensegrity structures with variable stiffness and shape changing ability T2 - Annual Meeting of the DFG Priority Programme Soft Material Robotic Systems, SPP2100, 02-04. März 2020, Schneverdingen Y1 - 2020 ER - TY - JOUR A1 - Schorr, Philipp A1 - Böhm, Valter A1 - Zentner, Lena A1 - Zimmermann, Klaus T1 - Motion characteristics of a vibration driven mobile tensegrity structure with multiple stable equilibrium states JF - Journal of Sound and Vibration N2 - A novel type of a vibration driven motion system based on a compliant tensegrity structure with multiple stable equilibrium states is considered. These equilibrium configurations correspond to different prestress states with different dynamical properties. Therefore, the motion characteristics can be varied by changing the equilibrium state. For the application in the fields of mobile robotics, these discrete adjustable dynamics are advantageous. The vibration modes of the structure as well as the corresponding motion characteristics of the system can be adapted to the given environmental conditions in order to ensure a reliable motion. In this paper, dynamical investigations of an exemplary two-dimensional multistable tensegrity structure are considered. For the chosen parameter values the structure features two relevant equilibrium configurations. The resulting motion system is in contact to a horizontal plane due to gravity and the actuation is realized by the harmonic variation of the length of a single tensioned member. The motion of the system is simulated for various actuation frequencies with the different equilibrium states as an initial configuration. A uniaxial or a planar movement occurs depending on the selection of the actuated member within the tensegrity structure. The steady state motion is evaluated regarding motion characteristics like the steady state velocity. Moreover, the influences on the motion behavior caused by the different equilibrium states as an initial condition are emphasized. (C) 2018 Elsevier Ltd. All rights reserved. KW - Compliant tensegrity structure KW - LOCOMOTION KW - Multistability KW - Vibration driven motion Y1 - 2018 U6 - https://doi.org/10.1016/j.jsv.2018.09.019 VL - 437 IS - December SP - 198 EP - 208 PB - Elsevier ER - TY - CHAP A1 - Schorr, Philipp A1 - Schale, Florian A1 - Otterbach, Jean Marc A1 - Zentner, Lena A1 - Zimmermann, Klaus A1 - Böhm, Valter T1 - Investigation of a Multistable Tensegrity Robot applied as Tilting Locomotion System T2 - Proceedings of the 2020 IEEE International Conference on Robotics and Automation (ICRA): 31 May-31 August 2020, Paris N2 - This paper describes the development of a tilting locomotion system based on a compliant tensegrity structure with multiple stable equilibrium configurations. A tensegrity structure featuring 4 stable equilibrium states is considered. The mechanical model of the structure is presented and the according equations of motion are derived. The variation of the length of selected structural members allows to influence the prestress state and the corresponding shape of the tensegrity structure. Based on bifurcation analyses a reliable actuation strategy to control the current equilibrium state is designed. In this work, the tensegrity structure is assumed to be in contact with a horizontal plane due to gravity. The derived actuation strategy is utilized to generate tilting locomotion by successively changing the equilibrium state. Numerical simulations are evaluated considering the locomotion characteristics. In order to validate this theoretical approach a prototype is developed. Experiments regarding to the equilibrium configurations, the actuation strategy and the locomotion characteristics are evaluated using image processing tools and motion capturing. The results verify the theoretical data and confirm the working principle of the investigated tilting locomotion system. This approach represents a feasible actuation strategy to realize a reliable tilting locomotion utilizing the multistability of compliant tensegrity structures. KW - actuators KW - bifurcation KW - mechanical stability KW - mobile robots KW - motion control KW - numerical analysis KW - robot dynamics KW - robot kinematics KW - vibration control Y1 - 2020 U6 - https://doi.org/10.1109/ICRA40945.2020.9196706 SP - 2932 EP - 2938 ER - TY - CHAP A1 - Schorr, Philipp A1 - Böhm, Valter A1 - Zentner, Lena A1 - Zimmermann, Klaus ED - Gusikhin, Oleg ED - Madani, Kurosh T1 - Design of a Vibration Driven Motion System Based on a Multistable Tensegrity Structure T2 - ICINCO 2018: proceedings of the 15th International Conference on Informatics in Control, Automation and Robotics, Porto, Portugal, July 29-31, 2018 N2 - In this paper a novel approach to realize a uniaxial bidirectional vibration driven motion system with controllable direction of motion is investigated. The considered motion system bases on a tensegrity structure with multiple stable equilibrium configurations. The structure is in contact with a horizontal plane due to gravity and the actuation is realized by the harmonic change of the length of a selected member. Beside varying the actuation parameters, the direction of motion can be controlled by changing the equilibrium configuration of the tensegrity structure. In this paper the topology of the tensegrity structure and the parameter values are chosen appropriately to provide two symmetric equilibrium configurations. A change of the equilibrium state yields a novel configuration of the entire motion system which is symmetric to the original state. Utilizing the symmetry of the system the same actuation yields an opposite motion. This approach represents a reliable opportunity to control the direction of motion by changing the equilibrium state for constant actuation parameters. This paper focuses on the parameter selection and the design of the actuation of the vibration driven motion system. The working principle of the vibration driven motion system is verified by numerical simulations. This contribution represents the theoretical investigation for the further development of a prototype. KW - Compliant tensegrity structure KW - Vibration driven motion multistability Y1 - 2020 SN - 978-3-030-31992-2 U6 - https://doi.org/10.1007/978-3-030-31993-9_14 VL - 613 SP - 302 EP - 317 PB - Springer CY - Cham ER - TY - CHAP A1 - Schorr, Philipp A1 - Chavez, Jhohan A1 - Zentner, Lena A1 - Böhm, Valter ED - Zentner, Lena ED - Strehle, Steffen T1 - Reconfigurable Planar Quadrilateral Linkages Based on the Tensegrity Principle T2 - Microactuators, Microsensors and Micromechanisms, MAMM, 2020 N2 - A feasible possibility to develop planar reconfigurable mechanisms is introduced in this work. Applying the tensegrity principle to common four-bar linkages allows a controllable change between two configurations of the mechanism. These two states correspond to different working spaces which vary regarding to the kinematic and mechanical properties. Therefore, the reconfiguration of the mechanism enables two different operation modes. Hence, this kind of mechanism enables the advantageous properties of conventional linkages with an additional enhanced adaptability of the kinematic and mechanic behavior. Beside the conceptual design of such tensegrity-based mechanisms, a reconfigurable four-bar parallel linkage is considered exemplarily. Numerical simulations are evaluated focusing on the kinematic behavior and the structural mechanics of this mechanism. Especially the reconfiguration of the mechanism by changing between two different working spaces is considered. The simulation results clarify the benefit of utilizing the tensegrity principle in mechanism theory. Adding only a few members to the original linkage enables a reconfigurable mechanism with comparable complexity. KW - Planar four-bar linkage KW - Reconfigurable mechanisms KW - tensegrity Y1 - 2021 SN - 978-3-030-61651-9 U6 - https://doi.org/10.1007/978-3-030-61652-6_5 SP - 48 EP - 57 PB - Springer International Publishing CY - Cham ER - TY - CHAP A1 - Böhm, Valter A1 - Schorr, Philipp A1 - Zimmermann, Klaus A1 - Zentner, Lena T1 - An Approach to the Estimation of the Actuation Parameters for Mobile Tensegrity Robots with Tilting Movement Sequences T2 - 2018 International Conference on Reconfigurable Mechanisms and Robots (ReMAR); 20-22 June 2018; Delft, Netherlands N2 - This paper deals with the locomotion by tilting sequences of shape-variable compliant tensegrity structures. The shape of these structures is controlled by manipulating their prestress state. The tensegrity structure is tilting as consequence of a suitable variation of its shape. By multiple repetition of such tilting sequences a motion is generated. Quasi-static considerations for the considered structures are presented in order to estimate the actuation parameters. For a proper number of actuators this quasi-static approach enables an analytical calculation of the actuation parameters of the structure in order to control the geometrical configuration as required. As an example a two-dimensional tensegrity structure which is in contact with a horizontal plane due to gravity is considered. By successive tilting sequences a uniaxial motion results. The excitation of the structure is calculated for a given change of shape with the quasi-static analysis. The according results are compared with transient dynamic simulations. Qualitative conclusions about the motion behavior and the usability of the quasi-static approach are given. KW - mobile robots KW - motion control KW - robot dynamics KW - structural engineering Y1 - 2018 U6 - https://doi.org/10.1109/REMAR.2018.8449871 SP - 1 EP - 8 PB - IEEE ER - TY - CHAP A1 - Carrillo Li, Enrique Roberto A1 - Schorr, Philipp A1 - Kaufhold, Tobias A1 - Rodríguez Hernández, Jorge Antonio A1 - Zentner, Lena A1 - Zimmermann, Klaus A1 - Böhm, Valter ED - Awrejcewicz, Jan ED - Kaźmierczak, Markek ED - Olejnik, Paweł T1 - Kinematic analysis of the rolling locomotion of mobile robots based on tensegrity structures with spatially curved compressed components T2 - Applicable Solutions in Non-Linear Dynamical Systems; 15th International Conference "Dynamical Systems - Theory and Applications" (DSTA 2019, 2-5 December, 2019, Lodz, Poland N2 - In this work, a tensegrity structure with spatially curved members is applied as rolling locomotion system. The actuation of the structure allows a variation of the originally cylindrical shape to a conical shape. Moreover, the structure is equipped with internal movable masses to control the position of the center of mass of the structure. To control the locomotion system a reliable actuation strategy is required. Therefore, the kinematics of the system considering the nonholonomic constraints are derived in this paper. Based on the resulting insight in the locomotion behavior a feasible actuation strategy is designed to control the trajectory of the system. To verify this approach kinematic analyses are evaluated numerically. The simulation data confirm the path following due to an appropriate shape change of the tensegrity structure. Thus, this system enables a two-dimensional rolling locomotion. The use of mechanically compliant tensegrity structures in mobile robots is an attractive research topic, due to the possibility to adjust their mechanical properties reversibly during locomotion. In this paper rolling locomotion of mobile robots based on simple tensegrity structures, consisting of three compressed spatially curved members connected to a continuous net of prestressed tensional members, is discussed. Planar locomotion of these robots is induced by the movement of internal masses. The movement direction can be changed by changing the robot's shape between a cylinder and a truncated cone. The paper focuses on the description of the kinematics of these systems with respect to the shape change. KW - Inverse kinematics KW - Nonholonomic mechanics KW - Tensegrity structure Y1 - 2019 UR - http://212.191.87.54:1616/k16/awrejcewicz/publikacje/T2.pdf SN - 978-83-66287-30-3 SP - 335 EP - 344 PB - Wydawnictwo Politechniki Łódzkiej CY - Łódź, Polen ER - TY - CHAP A1 - Schorr, Philipp A1 - Böhm, Valter A1 - Stepan, G. A1 - Zentner, Lena A1 - Zimmermann, Klaus A1 - Stépán, G. ED - Uhl, Tadeusz T1 - Multi-mode motion system based on a multistable tensegrity structure T2 - Advances in Mechanism and Machine Science : Proceedings of the 15th IFToMM World Congress on Mechanism and Machine Science N2 - This paper presents a multi-mode motion system based on a compliant tensegrity structure with multiple stable equilibrium configurations. The motion system is in contact to an arbitrarily shaped rigid ground due to gravity. The movement is realized by changing successively between different equilibrium states. Depending on the strategy of changing the equilibrium configuration, different motion types occur. The reachable area of the motion system can be enlarged by adapting the motion type depending on the given environmental characteristics. Furthermore, the efficiency of the motion can be improved by choosing the most suitable motion mode. Theoretical studies regarding the change of the equilibrium states are introduced. Moreover, simulation results for the different motion modes tilting, vibration driven and jumping are illustrated. The resulting motion characteristics emphasize the advantageous adaptability of the motion system regarding to varying environmental conditions. KW - bifurcation analysis KW - multimodal motion KW - tensegrity Y1 - 2019 SN - 978-3-030-20130-2 U6 - https://doi.org/10.1007/978-3-030-20131-9_296 VL - 73 SP - 3007 EP - 3016 PB - Springer CY - Cham ER - TY - CHAP A1 - Böhm, Valter A1 - Schorr, Philipp A1 - Feldmeier, T. A1 - Chavez, Jhohan A1 - Henning, S. A1 - Zimmermann, Klaus A1 - Zentner, Lena T1 - An Approach to Robotic End Effectors Based on Multistable Tensegrity Structures T2 - New Trends in Mechanism and Machine Science: 8th European Conference on Mechanism Science (EuCoMeS), 2020 N2 - In this paper compliant multistable tensegrity structures with discrete variable stiffness are investigated. The different stiffness states result from the different prestress states of these structures corresponding to the equilibrium configurations. Three planar tensegrity mechanisms with two stable equilibrium configurations are considered exemplarily. The overall stiffness of these structures is characterized by investigations with regard to their geometric nonlinear static behavior. Dynamical analyses show the possibility of the change between the equilibrium configurations and enable the derivation of suitable actuation strategies. KW - Compliant tensegrity structure KW - Multiple states of self-equilibrium KW - Variable stiffness Y1 - 2020 U6 - https://doi.org/10.1007/978-3-030-55061-5_53 SP - 470 EP - 478 PB - Springer ER - TY - CHAP A1 - Schorr, Philipp A1 - Böhm, Valter A1 - Zentner, Lena A1 - Zimmermann, Klaus T1 - Investigation of a tensegrity structure with multiple equilibrium configurations as jumping motion system T2 - Theoretical Approaches in Non-Linear Dynamical Systems : Proceedings of the 15th Conference on Dynamical Systems -Theory and Applications N2 - Often, the operating range of mobile robots is limited by environ- mental circumstances like obstacles or gaps. Therefore, an adaptation of the motion principle is required to enable an operating continuation of such robots. A jumping motion is a promising approach. This motion type allows to cross gaps or to overcome obstacles where common motion principles which bases on wheels or legs fail. However, especially during landing large forces occur as a consequence of the impact with the ground. This issue encourages the use of compliant tensegrity structures which feature a great shock resistance. In this paper a tensegrity structure with multiple equilibrium configurations is considered. The two-dimensional structure is equipped with two actuators to vary the prestress of the system. The tensegrity structure is in contact to a horizontal plane due to gravity. Two actuation strategies are derived. Beside varying the prestress state of the structure, a jump can be realized by changing the equilibrium configuration. Both actuation strategies and the corresponding motion characteristics are evaluated by numeric simulations. The results emphasize the advantageous properties of tensegrity structures for a jumping motion system. In particular, the multistabilty of the structure allows a simple actuation strategy for a reliable jumping motion. Y1 - 2019 UR - http://212.191.87.54:1616/k16/awrejcewicz/publikacje/T1.pdf SN - 978-83-66287-29-7 SP - 465 EP - 476 PB - Wydawnictwo Politechniki Łódzkiej CY - Łódź, Polen ER - TY - JOUR A1 - Schorr, Philipp A1 - Chavez, Jhohan A1 - Zentner, Lena A1 - Böhm, Valter T1 - Reconfiguration of planar quadrilateral linkages utilizing the tensegrity principle JF - Mechanism and machine theory N2 - The development of reconfigurable planar four-bar linkages by applying the tensegrity principle is considered. Conventional quadrilateral linkages enable two operation modes differing in the kinematic behavior. However, a change between these states is not possible due to the geometric constraints. To enable a reconfiguration between the different modes one-sided limited nonholonomic constraints are introduced in this work. This issue is realized by applying ropes that cannot resist compression. However, to guarantee an appropriate load case in operation a prestress within the mechanism is required. Hence, the linkage is extended to a tensegrity-based mechanism. The structural dynamics are derived using the LAGRANGE formalism and the structural behavior is evaluated using numerical simulations. Furthermore, a prototype of an exemplary tensegrity-based mechanism is manufactured and experiments regarding the mechanical properties, in particular the reconfiguration, are performed. The results suggest the potential benefit of applying the tensegrity principle within conventional planar four-bar linkages. KW - CONFIGURATION SYNTHESIS KW - MECHANISMS KW - Multibody dynamics KW - Planar four-bar linkage KW - Reconfiguration KW - Tensegrity-based mechanism Y1 - 2021 U6 - https://doi.org/10.1016/j.mechmachtheory.2020.104172 IS - 156 PB - Elsevier ER - TY - JOUR A1 - Schorr, Philipp A1 - Zentner, Lena A1 - Zimmermann, Klaus A1 - Böhm, Valter T1 - Jumping locomotion system based on a multistable tensegrity structure JF - Mechanical systems and signal processing N2 - All known locomotion principles are limited respective to environmental conditions. Often, the occurrence of obstacles or gaps means the break-off for the operating motion systems. For such circumstances, a controllable jumping locomotion is required to cross these barriers. However, this locomotion demands sophisticated requirements to the actuation. The abrupt actuation is commonly realized by high dynamic actuators or complex mechanisms. In this work, a simple solution utilizing the multistability of a compliant tensegrity structure is described. Therefore, a two-dimensional tensegrity structure featuring four stable equilibria is considered. Based on bifurcation analyses a feasible actuation to control the current equilibrium configuration is derived. Changing between selected equilibrium states enables a great difference in potential energy, which yields a jumping motion of the structure. Based on numerical simulations a suitable actuation strategy is chosen to overcome obstacle and steps by jumping forward or backward, respectively. The theoretical approach is examined experimentally with a prototype of the multistable tensegrity structure. (c) 2020 Elsevier Ltd. All rights reserved. All known locomotion principles are limited respective to environmental conditions. Often, the occurrence of obstacles or gaps means the break-off for the operating motion systems. For such circumstances, a controllable jumping locomotion is required to cross these barriers. However, this locomotion demands sophisticated requirements to the actuation. The abrupt actuation is commonly realized by high dynamic actuators or complex mechanisms. In this work, a simple solution utilizing the multistability of a compliant tensegrity structure is described. Therefore, a two-dimensional tensegrity structure featuring four stable equilibria is considered. Based on bifurcation analyses a feasible actuation to control the current equilibrium configuration is derived. Changing between selected equilibrium states enables a great difference in potential energy, which yields a jumping motion of the structure. Based on numerical simulations a suitable actuation strategy is chosen to overcome obstacle and steps by jumping forward or backward, respectively. The theoretical approach is examined experimentally with a prototype of the multistable tensegrity structure. KW - Compliant tensegrity structure KW - Multibody dynamics KW - Multistability KW - Non-classical locomotion Y1 - 2021 U6 - https://doi.org/10.1016/j.ymssp.2020.107384 IS - 152 PB - Elsevier ER - TY - JOUR A1 - Schorr, Philipp A1 - Carrillo Li, Enrique Roberto A1 - Kaufhold, Tobias A1 - Rodriguez Hernandez, Jorge Antonio A1 - Zentner, Lena A1 - Zimmermann, Klaus A1 - Böhm, Valter T1 - Kinematic analysis of a rolling tensegrity structure with spatially curved members JF - Meccanica N2 - In this work, a tensegrity structure with spatially curved members is applied as rolling locomotion system. The actuation of the structure allows a variation of the originally cylindrical shape to a conical shape. Moreover, the structure is equipped with internal movable masses to control the position of the center of mass of the structure. To control the locomotion system a reliable actuation strategy is required. Therefore, the kinematics of the system considering the nonholonomic constraints are derived in this paper. Based on the resulting insight in the locomotion behavior a feasible actuation strategy is designed to control the trajectory of the system. To verify this approach kinematic analyses are evaluated numerically. The simulation data confirm the path following due to an appropriate shape change of the tensegrity structure. Thus, this system enables a two-dimensional rolling locomotion. KW - Tensegrity structure KW - Inverse kinematics KW - Nonholonomic mechanics Y1 - 2021 U6 - https://doi.org/10.1007/s11012-020-01199-x SN - 0025-6455 VL - 56 SP - 953 EP - 961 PB - Springer ER - TY - CHAP A1 - Herrmann, David A1 - Schaeffer, Leon A1 - Zentner, Lena A1 - Böhm, Valter T1 - Theoretische und experimentelle Voruntersuchungen von Manipulatoren auf Basis von nachgiebigen Tensegrity-Strukturen T2 - 9. IFToMM D-A-CH Konferenz, 16./17. März 2023, Universität Basel N2 - In this paper, two compliant tensegrity manipulators are presented and contrasted with respect to their mechanical pro- perties and deformation capability. They differ in their topology, in the way they are actuated and also in their mechanical compliance. The mechanical compliance of the first system is based on the elasticity of the tensioned segments, while the compressed segments are rigid. The second system is based on elementary units, which are themselves spatial tensegrity structures. In this system, both the tension and compressed segments are compliant. Actuation of the first system occurs by changing the length of the tensile segments. In the second system, the change in shape of the overall system is realized by changing the shape of the compliant compressed segments N2 - Um die Leistungsfähigkeit von nachgiebigen Robotersystemen („Soft Robotics“) zu verbessern, werden immer neue Möglichkeiten zur Realisierung dieser Systeme gesucht. In vielen Anwendungen ist der Einsatz von mechanisch vorgespannten nachgiebigen Strukturen in diesen Systemen von Vorteil. Die Steifigkeit dieser Strukturen kann gezielt und gegebenenfalls reversibel variabel eingestellt werden. Die Formveränderung kann nur durch wenige Aktuatoren erzeugt werden. Nachgiebige Tensegrity-Strukturen, die auf hochelastischen Materialien basieren, entsprechen einer speziellen Klasse von mechanisch vorgespannten Strukturen. Sie werden durch druck- und zugbelastete Segmente gebildet, wobei die druckbelasteten Segmente untereinander nicht direkt verbunden sind. Die resultierende Form dieser Strukturen wird durch ihre Vorspannung bestimmt. Weiche Roboter, die auf diesen Strukturen basieren, bieten mehrere vorteilhafte Eigenschaften, wie z. B. Faltbarkeit/Entfaltbarkeit, geringe Masse, hohes Festigkeits-Gewichts-Verhältnis und stoßdämpfende Fähigkeiten [1]. Diese Strukturen haben eine ausgeprägte Fähigkeit, sowohl ihre Form als auch ihre Steifigkeit zu verändern. In den letzten Jahren hat das Interesse an der Erforschung von Robotersystemen, die auf diesen Strukturen basieren, zugenommen. Aktuelle Arbeiten konzentrieren sich auf die Entwicklung von mobilen Robotern [2]–[7] und Manipulatoren, die auf diesen Strukturen basieren [8]–[10]. Tensegrity-Manipulatoren werden typischerweise durch Kaskadierung von gleichartigen elementaren Einheiten gebildet, die nach dem Tensegrity-Prinzip untereinander verbunden werden. Die elementaren Einheiten sind entweder selber konventionelle Tensegrity-Strukturen oder einteilige planare bzw. räumliche Strukturen. In klassischen Tensegrity-Manipulatoren werden starre Drucksegmente und nicht elastische Zugsegmente verwendet. Die Formänderung dieser Systeme wird durch Änderung der Längen ausgewählter Zugsegmente realisiert. Dem gegenübergestellt können nachgiebige Tensegrity-Manipulatoren realisiert werden, indem die Zugsegmente der Struktur eine hohe Nachgiebigkeit aufweisen. Um die mechanische Nachgiebigkeit und Formänderungsfähigkeit von diesen nachgiebigen Manipulatoren zusätzlich zu erhöhen, ist auch der Einsatz von Tensegrity-Strukturen auf der Basis nachgiebiger Drucksegmente denkbar. Im vorliegenden Beitrag werden zwei nachgiebige Tensegrity-Manipulatoren vorgestellt und in Hinblick auf ihre mechanischen Eigenschaften und Formänderungsfähigkeit gegenübergestellt. Sie unterscheiden sich in ihrer Topologie, in der Art der Aktuierung und auch in der mechanischen Nachgiebigkeit. Die mechanische Nachgiebigkeit des ersten Systems beruht auf der Elastizität der Zugsegmente, die Drucksegmente sind starr. Die elementaren Einheiten bilden einteilige Strukturen. Das zweite System beruht auf elementaren Einheiten, die selbst räumliche Tensegrity-Strukturen sind. In diesem System sind sowohl die Zug- als auch die Drucksegmente nachgiebig. Die Aktuierung des ersten Systems erfolgt durch Längenänderung der Zugsegmente. Im zweiten System wird die Formänderung des Gesamtsystems durch Änderung der Form der nachgiebigen Drucksegmente realisiert. Die theoretischen Untersuchungen erfolgen unter Anwendung der statischen geometrisch nichtlinearen FE-Methode. Mit diesen Untersuchungen wird die Formveränderungsfähigkeit der beiden Systeme unter Variation ihrer Vorspannung untersucht und gegenübergestellt. Die experimentellen Untersuchungen an zwei Demonstratoren bestätigen die theoretischen Ergebnisse und zeigen die Anwendbarkeit von Systemen auf Basis dieser Strukturen als Manipulatoren auf. T2 - Preliminary theoretical and experimental investigations on manipulators based on compliant tensegrity structures Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:465-20230314-164736-8 PB - DuEPublico CY - Duisburg-Essen ER - TY - CHAP A1 - Herrmann, David A1 - Schaeffer, Leon A1 - Zentner, Lena A1 - Böhm, Valter T1 - Theoretical considerations on 3D tensegrity joints for the use in manipulation systems T2 - Engineering for a changing world : 60th ISC, Ilmenau Scientific Colloquium, Technische Universität Ilmenau, September 4-8, 2023 N2 - This paper presents a comprehensive analysis of a three-dimensional compliant tensegrity joint structure, examining its actuation, kinematics, and response to external loads. The study investigates a baseline configuration and two asymmetric variants of the joint. The relationship between the shape parameter and the parameters of the tensioned segments is derived, enabling the mathematical description of cable lengths for joint actuation. Geometric nonlinear static finite element simulations are performed to analyze the joint's response under various load conditions. The results reveal the joint's range of motion, the effect of different stiffness configurations, and its deformation behavior under external forces. The study highlights the asymmetric nature of the joint and its potential for targeted motion restriction. These findings advance the general understanding of the behavior of the considered tensegrity joint and provide valuable insights for their design and application in soft robotic systems. Y1 - 2023 U6 - https://doi.org/10.22032/dbt.58888 SP - 1 EP - 13 PB - Technische Universität Ilmenau CY - Ilmenau ER - TY - CHAP A1 - Herrmann, David A1 - Schaeffer, Leon A1 - Schmitt, Lukas A1 - Körber, Wolfgang A1 - Merker, Lukas A1 - Zentner, Lena A1 - Böhm, Valter T1 - Compliant Robotic Arm based on a Tensegrity Structure with x-shaped Members T2 - 2024 IEEE 7th International Conference on Soft Robotics (RoboSoft), San Diego, CA, USA. April 14-17, 2024 N2 - The use of intrinsically compliant tensegrity structures in manipulation systems is an attractive research topic. In this paper a 3D compliant robotic arm based on a stacked tensegrity structure consisting of x-shaped rigid members is considered. The rigid members are interconnected by a net of prestressed, tensioned members with pronounced intrinsic elasticity and by inelastic tensioned members. The system's motion is achieved by length-change of the inelastic tensioned members. The operating principle of the system is discussed with the help of kinematic considerations and verified by experiments. KW - Geometry KW - Three-dimensional displays KW - Shape KW - Prototypes KW - Kinematics KW - Soft robotics KW - Manipulators Y1 - 2024 U6 - https://doi.org/10.1109/RoboSoft60065.2024.10521941 SP - 1047 PB - IEEE ER - TY - JOUR A1 - Jahn, Hannes A1 - Böhm, Valter A1 - Zentner, Lena T1 - Analysis of deformation in tensegrity structures with curved compressed members JF - Meccanica N2 - AbstractTensegrity structures are prestressed structures consisting of compressed members connected by prestressed tensioned members. Due to their properties, such as flexibility and lightness, mobile robots based on these structures are an attractive subject of research and are suitable for space applications. In this work, a mobile robot based on a tensegrity structure with two curved members connected by eight tensioned strings is analyzed in terms of deformation in the curved members. Further, the difference in locomotion trajectory between the undeformed and deformed structure after the prestress is analyzed. For that, the theory of large deflections of rod-like structures is used. To determine the relationship between acting forces and the deformation, the structure is optimized using minimization algorithms in Python. The results are validated by parameter studies in FEM. The analysis shows that the distance between the two curved members significantly influences the structure’s locomotion. It can be said that the deformation of the components significantly influences the locomotion of tensegrity structures and should be considered when analyzing highly compliant structures. KW - Rolling locomotion KW - Mobile robot KW - Tensegrity structures KW - Deformation of compressedmembers KW - Finite element simulations Y1 - 2024 U6 - https://doi.org/10.1007/s11012-024-01833-y SN - 0025-6455 PB - Springer Nature ER -