Inchworm-Inspired soft robot with magnetic driving based on PDMS, EGaIn and NdFeB (PEN) combination

Soft robot has been widely used in many fields owing to flexible movement, good deformability and strong adaptability. To control soft robots, a variety of driving mechanisms have been explored, including light, electric, gas, and magnetic actuation. Of these mechanisms, magnetic actuation has gained significant importance due to its penetrability, rapid response and non-destructive performance. However, substrates made of soft composite films often suffer from poor toughness and flexibility. To address this issue, we designed a composite film composed of polydimethylsiloxane (PDMS), eutectic gallium indium (EGaIn) and neodymium ferrite boron (NdFeB) (PEN) at an optimal ratio of 10:4:2. The film exhibits exceptional properties, including an elastic modulus of 1.17 MPa, thermal stability of 2.6625e-6 K−1, contact angle of 121.1°, tearing energy of 7.36 KJ/m2, swelling degree of 0.02446 and cross-linking density of 1.52 × 10-3mol/cm3. As a result, it is capable of achieving superior motion performance for inchworm-like robots. With the help of real-time motion analysis, we obtained the motion stage, actuating velocity of 48.3 mm/s and sequential magnetic control time of 20 s for the inchworm-like soft robot. These results indicate a high degree of sensitivity and stability. In conclusion, the developed inchworm-robot based on the novel PEN material exhibits exceptional deformation, flexibility, velocity and magnetic controllability under magnetic driving.