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 - 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 - 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 -