4.6 Materials and fabrication of the robots in applications

The robotic fin (Figure 4b) comprises two Double Bellows and a PVC sheet (160 mm × 75 mm 0.5 mm). All the frames and connectors in this application are 3D-printed (DSM IMAGE8200 pro, WeNext Technology Co., Ltd., China), including the mounting base of the force sensor (LSB201, FUTEK Advanced Sensor Technology, Inc., USA). The robotic fin, the force sensor, and the sensor mounting base are fabricated and fixed on the 6-DOFs manipulator (JAKA Zu 7, JAKA Robotics, China) to adjust and stabilize the position conveniently. Then, we immerse the robotic fin in the water tank (600 mm × 400 mm 450 mm, water depth 300 mm) to investigate the actuation performance (Figure S8a).
The fabric-based soft finger (Figure S8d) is fabricated by 30D rib weft-knitted polyester fabric coated with 0.2 mm-TPU (Jiaxing Yingcheng Textile Co., Ltd, China). A laser cutter (VLS 3.50, Universal Laser Systems, USA) trims the fabric to the target CAD pattern, and then a heat-sealing machine (customized) manually seals the fabric pieces into actuators. Specific methods are referred to the work of Feng et al. [8]. For the extensive application, Ecoflex 0030 (Smooth On, USA) and M 4601 (Wacker, Germany) are mixed 1:1 (mass) to cast the fiber-reinforced silicone actuator (62.1 g).
For the quadruped robot (244.1 g), a body frame connects four Triple Bellows, shown in Figure S8g. The body length of the quadruped robot is 220 mm, and each foot is 100 mm long (Figure 5b). Silicone feet (Sujie, China) are stuck on the caps of the Triple Bellows to prevent slipping.