A Soft Robotic Gripper with Anti-Freezing Ionic Hydrogel-Based Sensors for Learning-Based Object Recognition

Soft robotic grippers possess high structural compliance and adaptability for grasping objects with unknown and irregular shapes and sizes. To enable more dexterous manipulation, soft sensors with similar mechanical properties to common elastomer materials are desired to be integrated into soft grippers. In this paper, we develop ionic hydrogel-based strain and tactile sensors and integrate these sensors into a three-finger soft gripper for learning-based object recognition. Such hydrogel-based sensors have excellent conductivity, high stretchability and toughness, good ambient stability, and unique anti-freezing property, and can be readily attached to a soft gripper at desired locations for strain and tactile sensing. Based on a deep-learning model, we demonstrate the capability of the sensory soft gripper for object grasping and recognition at both room and freezing temperatures, and achieve high recognition accuracy close to 100% for 10 typical objects. With these abilities, our gripper can find interesting applications such as sorting food or chemicals in low temperature storage and cold chain transportation, or manipulating equipment in polar area.