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 - Sindersberger, Dirk A1 - Prem, Nina A1 - Monkman, Gareth J. A1 - Zimmermann, Klaus ED - Schlaak, Helmut T1 - Self-Sensing Electroadhesive Polymer Gripper with Magnetically Controllable Surface Geometry T2 - Actuator 2021, International Conference and Exhibition on New Actuator Systems and Applications: GMM conference, February 17-19, 2021, online event N2 - Compared to conventional end effectors, electro-adhesive grippers enable the handling of sensitive, soft or air-permeable materials [1]. The prehension force is based on a strong electric field generated by electrodes resulting in a polarisation of the dielectric and the generation of mirror charges in the workpiece. When the electrode supply voltage is deactivated, the electric field drops,but an electrostatic field remains due to remanent polarisation of the dielectric. The residual charge on the gripper surface reduces only slowly and in combination with other influencing factors can prevent the workpieces from being ejected temporarily or completely. In this work a solution to this problem is presented by means of gripper surface deforming caused by the applicat ion of a magnetic field to a magneto- active polymer (MAP) actuator. The in-creased distance between the workpiece and the dielectric enables precise and controlled ejection. In addition to compliance and deformability, the employment of soft smart materials enables the integration of self-sens-ing mechanisms for the measurement of surface deformation. The embedding of electrically conductive flexible electrodes within the soft silicone dielectric sup port such movements and serves as the n ecessary electrodes for electroadhesion. Since the implementation of the end effectoris based entirely on soft materials, the self-sensing magnetically controllable electroadhesive gripper (SMEG) can be produced in a shape deposition manufacturing (SDM) process [2], [3] and is highly applicable to the field of soft robotics. Y1 - 2021 SN - 9783800754540 U6 - https://doi.org/10.1002/macp.201800222 SP - 318 EP - 320 PB - VDE VERLAG CY - Berlin; Offenbach 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 - 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 Vega, Jhohan Harvey A1 - Ziolkowski, Marek A1 - Schorr, Philipp A1 - Spiess, Lothar A1 - Böhm, Valter A1 - Zimmermann, Klaus T1 - A method to approach constant isotropic permeabilities and demagnetization factors of magneto-rheological elastomers JF - Journal of Magnetism and Magnetic Materials N2 - The use of non-conventional materials is nowadays of much interest in scientific community. Magneto-rheological elastomers are hybrid materials, which in presence of magnetic fields state a change in their mechanical properties. They are composed by an elastomeric matrix with embedded magnetic particles. One of the most attractive features of these materials is that as soon as the magnetic field is removed from the material, the original mechanical properties are completely recovered, with negligible differences in comparison to the original state. This paper focuses on the study of magnetic characteristics of these smart materials, such as relative permeability and demagnetizing factors, for samples with different volume concentration of ferromagnetic particles. KW - Demagnetization factor KW - Finite element simulations KW - Magneto-rheological elastomer KW - Relative permeability KW - Static magnetic field Y1 - 2021 U6 - https://doi.org/10.1016/j.jmmm.2021.167742 VL - 527 PB - Elsevier ER - TY - CHAP A1 - Chavez Vega, Jhohan Harvey A1 - Böhm, Valter A1 - Becker, Tatiana I. A1 - Gast, Simon A1 - Zeidis, Igor A1 - Zimmermann, Klaus ED - Odenbach, Stefan T1 - Actuators based on a controlled particlematrix interaction in magnetic hybrid materials for applications in locomotion and manipulation systems T2 - Magnetic Hybrid-Materials: Multi-scale modelling synthesis and applications N2 - The paper deals with the investigation of magneto-sensitive elastomers(MSE) and their application in technical actuator systems. MSE consist of an elasticmatrix containing suspended magnetically soft and/or hard particles. Additionally,they can also contain silicone oil, graphite particles, thermoplastic components, etc.,in various concentrations in order to tune specific properties such as viscosity, con-ductivity and thermoelasticity, respectively. The focuses of investigations are thebeneficial properties of MSE in prototypes for locomotion and manipulation purposesthat possess an integrated sensor function. The research follows the principle of amodel-based design, i.e. the working steps are ideation, mathematical modelling,material characterization as well as building first functional models (prototypes). Thedeveloped apedal (without legs) and non-wheeled locomotion systems use the inter-play between material deformations and the mechanical motion in connection with theissues of control and stability. Non-linear friction phenomena lead to a monotonousforward motion of the systems. The aim of this study is the design of such mechanicalstructures, which reduce the control costs. The investigations deal with the movementand control of‘intelligent’mechanisms, for which the magnetically field-controlledparticle-matrix interactions provide an appropriate approach. The presented grippersenclose partially gripped objects, which is an advantage for handling sensitive objects.Form-fit grippers with adaptable contour at the contact area enable a uniform pressuredistribution on the surface of gripped objects. Furthermore, with the possibility ofactive shape adaptation, objects with significantly differing geometries can be gripped.To realise the desired active shape adaptation, the effect of field-induced plasticity ofMSE is used. The first developed prototypes mainly confirm the functional principles assuch without direct application. For this, besides the ability of locomotion andmanipulation itself, further technological possibilities have to be added to the systems. KW - apedal locomotion systems KW - field-controlled particle-matrix interaction KW - field-induced plasticity KW - form-fit gripper KW - integrated sensor-actuator systems KW - magneto-sensitive elastomer Y1 - 2021 SN - 9783110569636 U6 - https://doi.org/10.1515/9783110569636-027 N1 - Zuerst erschienen in: Physical Sciences Reviews, 2020, pp. 20190087 SP - 653 EP - 680 PB - De Gruyter CY - Berlin ER -