Far-Field Magnetic Sensing on Soft Origami Actuator for Spatial Multidimensional Movement and Force Perception

Soft robots exhibit exceptional flexibility and adaptability, enabling them to dynamically adjust their body shapes in unstructured environments for a wide range of applications. This motivates an extensive investigation of soft sensing techniques to accommodate such versatility. Magnetic sensing mechanisms present promising adaptability for soft robots due to their ease of integration and extensive detection range features. In this study, we explore the potential of utilizing far-field magnetic sensing in combination with a soft actuator model-based approach for multimodal perception. We introduce a Soft Farfield Magnetic Origami design, which incorporates a concise Hall sensory array into soft pneumatic origami actuators. The Hall sensory array is utilized to track the unique distal position of the soft actuator. This facilitates the further retrieval of spatial multidimensional movements, including linear and omnidirectional bending motions, as well as interactive forces. This multimodal sensing capability is supported by the modeled relationships between the desired sensing modalities and the measurable set of soft origami actuators, in terms of distal position and pressure. Our proposed approach showcases accurate spatial kinematic perception with a root-mean-square deviation of 0.36 mm in length, 0.02 rad in angle, and an interactive force variation detection with a root-mean-square deviation of 0.89 N. This comprehensive methodology from concept, modeling, design, and fabrication, to validation, facilitates position feedback control and interactive force tuning in soft robotic systems.