A Doughnut Shaped Soft Gripper Based on 4D Printed Hydrogels. - Zhe Qiu; Zaiyang Liu; Yitong Xue; Qinshang Xie; Takuto Chihara; Yuma Sakurai; Tatsuya Kobayashi; Tsubasa Honma; Hidemitsu Furukawa; Zhongkui Wang (RCAR, 2024)