@inproceedings{HerrmannSchaefferLehmannetal., author = {Herrmann, David and Schaeffer, Leon and Lehmann, Lukas and B{\"o}hm, Valter and Rieffel, John}, title = {Basic Investigations on a Compliant 2D Tensegrity Grid for the Use in Soft Robotic Applications}, series = {2024 6th International Conference on Reconfigurable Mechanisms and Robots (ReMAR), 23-26 June 2024, Chicago, IL, USA}, booktitle = {2024 6th International Conference on Reconfigurable Mechanisms and Robots (ReMAR), 23-26 June 2024, Chicago, IL, USA}, publisher = {IEEE}, isbn = {979-8-3503-9596-9}, doi = {10.1109/ReMAR61031.2024.10619926}, pages = {652 -- 657}, abstract = {The use of compliant tensegrity grids in soft robotic applications is a promising research topic. By using these grids, systems with large shape and stiffness change ability can be realized. In this paper, different tensegrity grid variants, consisting of rigid members indirectly connected via compliant tensioned members, are presented. A selected grid variant is analyzed in more detail for shape adaptation. Therefore the use of the grid as end effector in form-fit grippers is selected as a specific application case. Covariance Matrix Adaptation Evolution Strategies are used to optimize actuators for two given shape function variants and an evaluation is carried out.}, language = {en} } @misc{HerrmannSchaefferBoehm, author = {Herrmann, David and Schaeffer, Leon and B{\"o}hm, Valter}, title = {Theoretical considerations on 2D multistable tensegrity structures based on equilateral triangles}, series = {MMT Symposium (Mechanism and Machine Theory Symposium): Book of Abstracts ; June 26-28, 2024. - Guimar{\~a}es, Portugal}, journal = {MMT Symposium (Mechanism and Machine Theory Symposium): Book of Abstracts ; June 26-28, 2024. - Guimar{\~a}es, Portugal}, number = {1. edition}, editor = {Flores, Paulo and Marques, Filipe and Da Rodrigues Silva, Mariana}, publisher = {Departamento de Engenharia Mec{\^a}nica, Universidade do Minho}, address = {Guimar{\~a}es, Portugal}, isbn = {978-989-33-6448-2}, pages = {403 -- 404}, language = {en} } @inproceedings{SchaefferHerrmannBoehm, author = {Schaeffer, Leon and Herrmann, David and B{\"o}hm, Valter}, title = {Voruntersuchung einer vorgespannten nachgiebigen Struktur f{\"u}r den Einsatz in dynamischen Handorthesen}, series = {9. IFToMM D-A-CH Konferenz, 16./17. M{\"a}rz 2023, Universit{\"a}t Basel}, booktitle = {9. IFToMM D-A-CH Konferenz, 16./17. M{\"a}rz 2023, Universit{\"a}t Basel}, publisher = {DuEPublico}, address = {Duisburg-Essen}, doi = {10.17185/duepublico/77392}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:465-20230314-153711-8}, abstract = {In diesem Beitrag erfolgt die theoretische Untersuchung einer zweidimensionalen nachgiebigen Tensegrity-Struktur in Hinsicht auf ihre potenzielle Eignung als Basisstruktur f{\"u}r eine dynamische Handorthese. Translatorische und rotatorische relative Bewegungsm{\"o}glichkeiten zwischen den Drucksegmenten der Struktur sind m{\"o}glich, da diese Segmente durch nachgiebige Zugsegmente miteinander verbunden sind. Die Form der Struktur und ihre Vorspannung in einer statisch stabilen Gleichgewichtskonfiguration werden mit Hilfe der Minimierung des Kr{\"a}fte- und Momentenungleichgewichts, der Betrachtung der potentiellen Energie der Struktur und einem Ansatz mittels statischer Finite-Elemente-Methode (FEM) in Abh{\"a}ngigkeit der Segmentparameter untersucht.}, language = {de} } @article{SchaefferHerrmannSchratzenstalleretal., author = {Schaeffer, Leon and Herrmann, David and Schratzenstaller, Thomas and Dendorfer, Sebastian and B{\"o}hm, Valter}, title = {Preliminary theoretical considerations on the stiffness characteristics of a tensegrity joint for the use in dynamic orthoses}, series = {Journal of Medical Robotics Research}, journal = {Journal of Medical Robotics Research}, publisher = {World Scientific}, doi = {10.1142/S2424905X23400081}, abstract = {Early motion therapy plays an important role for effective long-term healing of joint injuries. In many cases, conventional dynamic orthoses fail to address the intricate movement possibilities of the underlying joints, limited by their simplistic joint representations, often represented by revolute joints, enabling rotations by only one axis. In this paper, a two-dimensional compliant tensegrity joint for use in biomedical applications is investigated. It consists of two compressed members and five compliant tensioned members. Relative movement possibilities are realized by the intrinsic compliance of the structure. In the development of these systems, the first step is the determination of the static stable equilibrium. This analysis is conducted in this paper by considering the potential energy approach or by using the geometric nonlinear finite element method. The mechanical behavior of the structure is assessed with a specific emphasis on its mechanical compliance. The primary objective of this study is the investigation of the influence of structural parameters on the overall stiffness and movability of the structure. The results underscore the significant effect of member parameters on the stiffness and movability of the compliant tensegrity joint, particularly under varying load magnitudes. These findings provide insights for optimizing the joint's performance, contributing to its potential application in advanced orthotic and exoskeleton devices.}, language = {en} } @inproceedings{SchaefferHerrmannBoehm, author = {Schaeffer, Leon and Herrmann, David and B{\"o}hm, Valter}, title = {Concept of a wrist Hand Orthosis based on a prestressed compliant structure}, series = {Proceedings of the 7th International Conference on Biomedical Engineering and Applications (ICBEA), Hangzhou, China, 21-23 April 2023}, booktitle = {Proceedings of the 7th International Conference on Biomedical Engineering and Applications (ICBEA), Hangzhou, China, 21-23 April 2023}, publisher = {IEEE}, doi = {10.1109/ICBEA58866.2023.00024}, pages = {98 -- 103}, abstract = {In the treatment of hand injuries in the context of orthopedic care, movable wrist hand orthoses are used in numerous instances. Early motion therapy is in most cases advantageous for adequate, rapid and successful long-term healing of the hand. Conventional dynamic wrist hand orthoses can only be used for movement therapy to a limited extent since they represent the wrist as a simple rotating joint and neglect the complexity of the hand movement possibilities. In this paper, a preliminary concept for dynamic wrist hand orthoses based on prestressed compliant structures is presented. The distinctive feature of this concept lies in the enabling of multiaxial motion capabilities of the human hand without applying conventional joints. According to the concept the wrist region is surrounded by a prestressed compliant structure. Besides the derivation and description of the concept, a first three-dimensional computer-aided design is shown. Additionally, the necessary steps in the development of such a novel dynamic wrist orthosis are discussed.}, language = {en} } @inproceedings{HerrmannSchaefferLehmannetal., author = {Herrmann, David and Schaeffer, Leon and Lehmann, Lukas and Busch, Tobias and B{\"o}hm, Valter}, title = {Preliminary Theoretical Considerations on 2D Multistable Tensegrity Structures Based on Equilateral Triangles}, series = {New trends in mechanism and machine science: Proceedings of EuCoMeS 2024}, booktitle = {New trends in mechanism and machine science: Proceedings of EuCoMeS 2024}, editor = {Rosati, Giulio and Gasparetto, Alessandro and Ceccarelli, Marco}, publisher = {Springer}, address = {Cham}, isbn = {978-3-031-67294-1}, doi = {10.1007/978-3-031-67295-8_21}, pages = {183 -- 191}, language = {en} } @inproceedings{SchaefferHerrmannBoehm, author = {Schaeffer, Leon and Herrmann, David and B{\"o}hm, Valter}, title = {Preliminary theoretical considerations of a hand orthosis based on a prestressed, compliant structure}, series = {Proceedings of the 2023 International Symposium on Medical Robotics (ISMR), Atlanta, 19-21 April 2023}, booktitle = {Proceedings of the 2023 International Symposium on Medical Robotics (ISMR), Atlanta, 19-21 April 2023}, publisher = {IEEE}, doi = {10.1109/ISMR57123.2023.10130230}, pages = {1 -- 7}, abstract = {In the treatment of hand injuries in the context of orthopedic care, movable hand orthoses are used in many cases. Early motion therapy is in most cases advantageous for adequate, rapid, and successful long-term healing of the hand. Conventional mobile hand orthoses can only be used for movement therapy to a limited extent since they represent the wrist as a simple rotating joint and neglect the complexity of the movement possibilities of the hand. In this paper, a novel concept for movable hand orthoses based on prestressed compliant structures is presented. The advantage with this concept is that it replicates the multiaxial motion capabilities without the need for conventional joints. Besides the derivation and description of the concept, a first three-dimensional CAD design is shown. Additionally, the next planned steps in the development of such a novel dynamic hand orthosis are described.}, language = {en} } @inproceedings{SchaefferHerrmannBoehm, author = {Schaeffer, Leon and Herrmann, David and B{\"o}hm, Valter}, title = {Theoretical considerations on a 2D compliant tensegrity joint in context of a biomedical application}, series = {Engineering for a changing world : 60th ISC, Ilmenau Scientific Colloquium, Technische Universit{\"a}t Ilmenau, September 4-8, 2023}, booktitle = {Engineering for a changing world : 60th ISC, Ilmenau Scientific Colloquium, Technische Universit{\"a}t Ilmenau, September 4-8, 2023}, publisher = {Technische Universit{\"a}t Ilmenau}, address = {Ilmenau}, doi = {10.22032/dbt.58879}, pages = {1 -- 15}, abstract = {In this paper, a two-dimensional compliant tensegrity joint was investigated for potential biomedical applications such as orthotics or exoskeletons. The structure consists of two compressed members connected by five compliant tensioned members. The concept is based on the tensegrity principle, which allows the realization of dynamic orthoses without conventional hinge joints. Another advantage is the adaptability to the individual needs of the patient through a suitable design of the structure and the careful selection of the characteristics of the elements. Using geometric nonlinear analysis, the mechanical behavior of the structure was investigated, focusing on mechanical compliance. The main objective was to determine the influence of the initial length and stiffness of the tensioned members and the influence of the magnitude of external forces on the overall stiffness of the movable member of the structure. The results highlight the significant impact of member parameters on the structure's stiffness and movability under varying load magnitudes. The research laid the foundation for future development of dynamic orthoses based on this structure.}, language = {en} } @article{SchaefferHerrmannSchmausseretal., author = {Schaeffer, Leon and Herrmann, David and Schmausser, Theresa and Liebrecht, Melanie and Rambach, Felix and B{\"o}hm, Valter}, title = {Theoretische Untersuchungen zu einer neuartigen Handorthese : [Kurzfassung des Tagungsbeitrags]}, series = {10. IFToMM D-A-CH Konferenz 2024: 05./06. M{\"a}rz 2024, Universit{\"a}t Rostock.}, journal = {10. IFToMM D-A-CH Konferenz 2024: 05./06. M{\"a}rz 2024, Universit{\"a}t Rostock.}, doi = {10.17185/duepublico/81586}, language = {de} } @inproceedings{SchaefferHerrmannBoehm, author = {Schaeffer, Leon and Herrmann, David and B{\"o}hm, Valter}, title = {Preliminary considerations on the form-finding of a tensegrity joint to be used in dynamic orthoses}, series = {8th International Conference on Biomedical Engineering and Applications (ICBEA 2024), Tokio, 18-21. March 2024}, booktitle = {8th International Conference on Biomedical Engineering and Applications (ICBEA 2024), Tokio, 18-21. March 2024}, edition = {accepted paper}, publisher = {ACM}, language = {en} } @inproceedings{SchaefferHerrmannBoehm, author = {Schaeffer, Leon and Herrmann, David and B{\"o}hm, Valter}, title = {Theoretical Investigations on a Dynamic Hand Orthosis Based on a Prestressed Compliant Structure with Respect to Stiffness and Wrist-Forces}, series = {2024 International Symposium on Medical Robotics (ISMR), 03-05 June 2024, Atlanta, GA, USA}, booktitle = {2024 International Symposium on Medical Robotics (ISMR), 03-05 June 2024, Atlanta, GA, USA}, publisher = {IEEE}, issn = {2771-9049}, doi = {10.1109/ISMR63436.2024.10585860}, abstract = {Many currently available dynamic hand orthoses use articulated connections that have one degree of freedom, such as hinge joints. These orthoses are therefore only able to replicate the multiaxial range of motion of the human hand to a limited extent. A possible solution for replecating the multiaxial movements of the hand is the use of pre-stressed compliant structures as a basis for the orthoses. After a brief description of this concept, the two main first steps by the development, the so called form-finding and the wrist-joint force characterization by hand movements are explained with theoretical analysis based on the static Finite Element Method. The influence of the orthosis parameters, global stiffness and geometric dimensions as well as the influence of the wrist-joint position relative to the orthosis are discussed. Finally, the next planned development steps towards to the first prototype are outlined.}, language = {en} } @inproceedings{HerrmannSchaefferZentneretal., author = {Herrmann, David and Schaeffer, Leon and Zentner, Lena and B{\"o}hm, Valter}, title = {Theoretische und experimentelle Voruntersuchungen von Manipulatoren auf Basis von nachgiebigen Tensegrity-Strukturen}, series = {9. IFToMM D-A-CH Konferenz, 16./17. M{\"a}rz 2023, Universit{\"a}t Basel}, booktitle = {9. IFToMM D-A-CH Konferenz, 16./17. M{\"a}rz 2023, Universit{\"a}t Basel}, publisher = {DuEPublico}, address = {Duisburg-Essen}, doi = {10.17185/duepublico/77397}, url = {http://nbn-resolving.de/urn:nbn:de:hbz:465-20230314-164736-8}, abstract = {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}, language = {de} } @inproceedings{HerrmannSchaefferSchmittetal., author = {Herrmann, David and Schaeffer, Leon and Schmitt, Lukas and K{\"o}rber, Wolfgang and Merker, Lukas and Zentner, Lena and B{\"o}hm, Valter}, title = {Compliant Robotic Arm based on a Tensegrity Structure with x-shaped Members}, series = {2024 IEEE 7th International Conference on Soft Robotics (RoboSoft), San Diego, CA, USA. April 14-17, 2024}, booktitle = {2024 IEEE 7th International Conference on Soft Robotics (RoboSoft), San Diego, CA, USA. April 14-17, 2024}, publisher = {IEEE}, doi = {10.1109/RoboSoft60065.2024.10521941}, pages = {1047}, abstract = {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.}, language = {en} } @misc{RieffelHerrmannLehmannetal., author = {Rieffel, John and Herrmann, David and Lehmann, Lukas and Schaeffer, Leon and B{\"o}hm, Valter}, title = {Illuminating the morphological diversity of 2D tensegrity grids}, series = {MMT Symposium (Mechanism and Machine Theory Symposium): Book of Abstracts ; June 26-28, 2024. - Guimar{\~a}es, Portugal}, journal = {MMT Symposium (Mechanism and Machine Theory Symposium): Book of Abstracts ; June 26-28, 2024. - Guimar{\~a}es, Portugal}, number = {1. edition}, editor = {Flores, Paulo and Marques, Filipe and Da Rodrigues Silva, Mariana}, publisher = {Departamento de Engenharia Mec{\^a}nica, Universidade do Minho}, address = {Guimar{\~a}es, Portugal}, isbn = {978-989-33-6448-2}, pages = {457 -- 458}, language = {en} } @inproceedings{HerrmannSchaefferZentneretal., author = {Herrmann, David and Schaeffer, Leon and Zentner, Lena and B{\"o}hm, Valter}, title = {Theoretical considerations on 3D tensegrity joints for the use in manipulation systems}, series = {Engineering for a changing world : 60th ISC, Ilmenau Scientific Colloquium, Technische Universit{\"a}t Ilmenau, September 4-8, 2023}, booktitle = {Engineering for a changing world : 60th ISC, Ilmenau Scientific Colloquium, Technische Universit{\"a}t Ilmenau, September 4-8, 2023}, publisher = {Technische Universit{\"a}t Ilmenau}, address = {Ilmenau}, doi = {10.22032/dbt.58888}, pages = {1 -- 13}, abstract = {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.}, language = {en} } @inproceedings{HerrmannSchaefferMerkeretal., author = {Herrmann, David and Schaeffer, Leon and Merker, Lukas and Zentner, Lena and B{\"o}hm, Valter}, title = {An Approach to the Realization of Multistable Tensegrity Structures with Deformable Compressed Members}, series = {Microactuators, Microsensors and Micromechanisms : MAMM 2024.}, booktitle = {Microactuators, Microsensors and Micromechanisms : MAMM 2024.}, editor = {Nguyen, Duc-Nam and Tran, Ngoc Dang Khoa and van Huynh, Tuan and Ono, Takahito and van Nguyen, Hieu and Pandey, Ashok Kumar}, publisher = {Springer Nature}, address = {Cham}, isbn = {978-3-031-83356-4}, doi = {10.1007/978-3-031-83357-1_34}, pages = {343 -- 350}, abstract = {Within this paper a novel tensegrity-mechanism is described. The mechanism is based on a tensegrity principle with multiple states of self-equilibrium. The tensegrity mechanism is built upon a mechanical compliant tensegrity structure, consisting of tensioned and compressed members. The existence of the different states of self-equilibrium depends on the parameters of deformable compressed members with continuous or discontinuous load-displacement characteristic. The working principle of the mechanism and the mechanical compliance is verified by theoretical investigations. Therefore, in the first step, the deformable compressed members are analyzed separately. With the help of the subsequent following form-finding procedure the equilibrium configurations of the mechanism and their static stability are analyzed in dependence of the mechanical parameters of the compressed and tensioned members. As a specific application case, the use of the mechanism as a variable stiffness device is discussed.}, language = {en} } @misc{HerrmannSchaefferSchmittetal., author = {Herrmann, David and Schaeffer, Leon and Schmitt, Lukas and K{\"o}rber, Wolfgang and Merker, Lukas and Zentner, Lena and B{\"o}hm, Valter}, title = {Design, Erprobung und Vergleich von zwei Manipulatoren auf Basis von nachgiebigen Tensegrity-Strukturen}, series = {10. IFToMM D-A-CH Konferenz 2024: 05./06. M{\"a}rz 2024, Universit{\"a}t Rostock}, journal = {10. IFToMM D-A-CH Konferenz 2024: 05./06. M{\"a}rz 2024, Universit{\"a}t Rostock}, doi = {10.17185/duepublico/81587}, abstract = {Kurzfassung des Tagungsbeitrags.}, language = {de} } @article{SchaefferHerrmannSchratzenstalleretal., author = {Schaeffer, Leon and Herrmann, David and Schratzenstaller, Thomas and Dendorfer, Sebastian and B{\"o}hm, Valter}, title = {Theoretical considerations on stiffness characteristics of a 3-dimensional tensegrity joint model for the use in dynamic hand orthoses}, series = {Journal of Medical Robotics Research}, journal = {Journal of Medical Robotics Research}, publisher = {World Scientific}, doi = {10.1142/S2424905X25400069}, language = {en} } @inproceedings{HerrmannKunzeKobesetal., author = {Herrmann, David and Kunze, Julian and Kobes, Julian and Seelecke, Stefan and Motzki, Paul and Rizzello, Gianluca and B{\"o}hm, Valter}, title = {A mobile tensegrity robot driven by rolled dielectric elastomer actuators}, series = {2025 IEEE 8th International Conference on Soft Robotics (RoboSoft), 22-26.April 2025, Lausanne}, booktitle = {2025 IEEE 8th International Conference on Soft Robotics (RoboSoft), 22-26.April 2025, Lausanne}, publisher = {IEEE}, doi = {10.1109/RoboSoft63089.2025.11020974}, pages = {6}, abstract = {This paper presents a tensegrity-based mobile robot powered by dielectric elastomer actuators (DEAs), which provide high compliance and adaptability. The design consists of two V-shaped members linked by DEAs, enabling both symmetrical and asymmetrical actuation for varied movement patterns. Modal analysis and simulations show that uniform DEA actuation supports efficient linear motion, while asymmetrical actuation enables controlled circular paths. Experimental testing highlights the influence of voltage waveforms, frequencies, and surface types on speed, with optimal performance achieved using rectangular waveforms on low-friction surfaces. The robot reaches a top speed of 188 mm/s, among the highest reported for DEA-driven robots.}, language = {en} } @inproceedings{SchaefferSchmausserHerrmannetal., author = {Schaeffer, Leon and Schmaußer, Theresa and Herrmann, David and Lehmann, Lukas and Dendorfer, Sebastian and B{\"o}hm, Valter}, title = {Multi-Body Simulation of a Dynamic Hand Orthosis based on a Prestressed Compliant Structure Incorporating the Human Hand}, series = {2025 International Symposium on Medical Robotics (ISMR), May 14-16, 2025, Atlanta, GA, USA,}, booktitle = {2025 International Symposium on Medical Robotics (ISMR), May 14-16, 2025, Atlanta, GA, USA,}, publisher = {IEEE}, doi = {10.1109/ISMR67322.2025.11025982}, pages = {80 -- 86}, abstract = {Many dynamic hand orthoses use one degree of freedom joints, such as hinge joints. Therefore, these orthoses can only partially replicate the complex, multi-axis movement of the hand. A possible solution for this is the use of prestressed compliant structures as the basis for orthoses. Determining the joint forces in the wrist and optimizing the dynamic orthosis to influence these forces as well as acting muscle forces are important steps in the development of these orthoses. For this reason, in this work multi-body simulation models of an orthosis with human hand models are presented. Based on these theoretical investigations, more detailed orthosis models as well as initial prototypes of prestressed compliant dynamic hand orthoses can be developed.}, language = {en} }