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Description
Magnetoactive elastomers (MAEs) consist of an elastic matrix with embedded micron-sized soft and/or hard magnetic particles. Such elastomers change their mechanical and rheological properties under the influence of external or internal magnetic fields. The magnetization of MAEs with hard magnetic particles in a strong magnetic field enables to produce elastic permanent magnets.
Magnetized MAEs are promising for use in the field of soft robotics. Motion systems realized using MAEs can achieve movement with a minimum number of actuators. In this work, the locomotion systems are made of a special type of MAEs as a functional element. We use beam-shaped MAEs, which are synthesized from a mixture of hard and soft magnetic particles. The MAE beams are permanently magnetized in a way that there is a south pole in the middle and a north pole at each end. The motion principle of the locomotion systems is based on the magnetic-field-induced bending deformation of the magnetized beam. The alternating magnetic field causing the beam deformation is generated by an electromagnetic coil integrated into the robot’s casing. Silicone bristles on the underside of the MAE beam provide asymmetrical friction conditions. Due to the cyclic interplay of friction forces and inertial forces caused by periodic bending, the robot shifts its position in each cycle and thereby moves forward. The movement speed is strongly dependent on the actuating frequency, with a maximum speed being achieved in the resonance range [1]. The use of two MAE functional elements, that are positioned parallel and mirror-symmetrical to each other, enables movement in a plane (Fig. 1). The principle of skid-steer is utilised. The movement speed along a curved path is determined by the choice of two actuating frequencies of the coils. The developed locomotion systems demonstrate good maneuverability and controllability. Their actuation method makes it easy to change the translational speed and yaw angle, making such systems suitable for use in complex operating conditions.
Fig. 1 Locomotion system for planar movement, left: top view, right: side view.
Acknowledgements
The work is funded by the Deutsche Forschungsgemeinschaft (DFG), project BE-6553/2-1.
References
[1] M. Reiche, T. I. Becker, G. V. Stepanov, and K. Zimmermann, “A Multipole Magnetoactive Elastomer for Vibration-Driven Locomotion,” Soft Robotics, vol. 10, no. 4. Mary Ann Liebert Inc, pp. 770–784, Aug. 01, 2023. doi: 10.1089/soro.2022.0106.
