A magnetically controlled bio-inspired cobweb soft robot based on structural topology optimization

Magnetically controlled micro-soft robots have been widely used in precise drug delivery and treatment of the gastrointestinal tract due to their advantages of high flexibility, environmental adaptability and non-contact control. Current micro-soft robots usually employ simple configurations and homogeneous materials, which limits their deformation and movement capacities. Therefore, it is of great significance to make a comprehensive investigation on the properties of key elastic structures of micro-soft robots with complex configurations. In the present work we conduct a systematic study on the design, preparation, experiments and simulations of the common disc-shaped robot and the proposed bio-inspired cobweb robot. Firstly, the topology optimization strategies are developed to design the configuration of the bio-inspired cobweb robot. Then, two kinds of robots are prepared by the mold manufacturing method of mixing NdFeB particles and silica gel solution in a certain proportion and pouring. Next, the magnetic control deformation experiments on these two kinds of robots are carried out, and the corresponding force-magnetic coupling model is established. The simulation and experimental results of the longitudinal and lateral displacement and the deflection on a specific path are compared and analyzed, which validates the accuracy of the simulation model. Finally, based on the developed numerical model, the effects of different residual magnetization and different magnet positions of the driving force of the cobweb structure are further predicted. The results indicate that the topologically optimized cobweb robot presents better deformation and movement capacities under the same size. These findings shed new light on engineering soft robots with complicated configurations and improved capacity than existing soft robots.