We report values of the zero temperature magnetic penetration depth A(O), microwave surface resistance R, , and gap ratio 2A(O)lk,T, in technologically useful thin films of NbN and Bat-,I(,BiO,. A novel analysis technique was used to extract the absolute magnitude of h(0) and 2A(O)/k,T, from shifts in resonant frequency of a parallel-plate resonator. For NbN and Bat-,K,BiO, values of X(O)=390Of200 A and 3300?200 A were obtained, respectively. The gap ratios were found to be 2A(O)/k,T,=4.1+0.1 and 3.8kO.5, respectively, for T,=16.3 K in NbN and T,=17.2 K in Bar-,&BiOs. The surface resistance measurements on BarK K,BiO, represent the lowest values ever reported at microwave frequencies in this material.
For soft robotics, shape memory alloy (SMA)‐based elastomeric actuators are a promising material combination but their maximum stroke is limited by the small inherent contraction of SMAs. In this work, a textile‐reinforced soft actuator is presented, which has additional SMA wire length included in the textile structure as well as a sensoric textile to track the actuator's pose. This strategy eliminates the need for external SMA wires with extra mechanical components. Various experiments with different excitation voltages are performed to show the actuator's performance. In a horizontal setup, the soft actuator reaches a bending angle of 270° at a power input of 18 W. The integrated sensor reflects the actuator's position but is also influenced by the temperature increase during activation. Moreover, an equivalent circuit model is proposed that includes the actuator, sensor, and mechanical support structure in one model. The model incorporates not only the mechanical but also the thermal and electrical domains. The simulation results are in good agreement with the experimental results.
Soft actuators are a promising option for the advancing fields of human-machine interaction and dexterous robots in complex environments. Shape memory alloy wire actuators can be integrated into fiber rubber composites for highly deformable structures. For autonomous, closed-loop control of such systems, additional integrated sensors are necessary. In this work, a soft actuator is presented that incorporates fiber-based actuators and sensors to monitor both deformation and temperature. The soft actuator showed considerable deformation around two solid body joints, which was then compared to the sensor signals, and their correlation was analyzed. Both, the actuator as well as the sensor materials were processed by braiding and tailored fiber placement before molding with silicone rubber. Finally, the novel fiber-rubber composite material was used to implement closed-loop control of the actuator with a maximum error of 0.5°.
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