Buoy structural high-sensitive magnetoelectric sensors for soft robots’ tactile sensing and avoiding obstacles

Abstract

Tactile sensing is one of the basic abilities for soft robots to sense the surroundings. Endowing soft robots with rich tactile perception is beneficial to improving the safety of object manipulation and avoiding the perceived obstacles, and thus to perform a task effectively in harsh environments. However, sensing is a grand challenge for soft robots due to their soft and flexible components. Here, we fabricated an externally magnetic guided soft robot in the capability of sensing the surroundings, which was comprised of a magnetoelectric sensor and a driving base. The top magnetoelectric sensor is mainly comprised of a buoy-type magnet (magnetic part) placed in the fluid-containing sac and a flexible conductive copper spiral helix (electric part). Attributing to the fluid interlink between the magnetic part and the electric part, such a buoy structure will result in a high sensitivity for external forces in contrast with the sensors interlinked two functional parts with silicon polymer or metallic spring. Once an externally mechanical force was applied on the fluid-containing sac, the magnetic flux change resulting from distance variation between magnetic part and electric part can lead to the generation of electric signal, and thereby the perception of obstacles. Integrating a driven base to the lower part of magnetoelectric sensor to form a soft robot with magnetic drive motion ability. We demonstrated that such a soft robot could detect sands’ falling and quickly moved away from the dangerous zones where the obstacles fell. It is believed that the proposed novel buoy structural design of magnetoelectric sensor can facilitate the development of the sensing ability of soft robots.