Shape and Force Sensing of A Soft SMA Planar Actuator for Soft Robots

Due to the large deformation and diversity of soft structures, many convenient sensors are hard to be used in soft robots/actuators. Although many novel flexible sensors have been developed in recent years, it is still difficult to accurately sense the shape and force of soft robots/actuators. In this paper, a shape sensing method and a variable-stiffness beam model are proposed to realize the shape and one-dimensional external force sensing, based on the SMA planar actuator(SPA) structure, with a strain gauge array sensing system. A shape reconstruction experiment and a force sensing experiment of a variable external force were implemented and the results validated the effectiveness and the accuracy of the above sensing methods, which extend application capability of the SMA-based soft actuator.