| Soft robots have characteristics such as high safety,strong adaptability,and good compliance,which make them highly valuable in fields such as bioengineering,industrial production,exploration and surveying,and biomedicine.In recent years,with the rapid development of materials science and processing technology,soft miniature robots have become a research hotspot in the field of robotics,particularly in the medical field.Soft miniature robots are capable of performing various medical procedures inside the human body,and their flexible bodies do not cause harm to organs and tissues.Soft miniature robots,due to their small size,face challenges in providing and driving internal energy sources.Therefore,pneumatic and hydraulic driving methods are not suitable for soft miniature robots.Magnetic field-based driving offers high efficiency and rapid responsiveness for soft miniature robots made of magnetic materials.Moreover,low-frequency and low-intensity magnetic fields do not pose harm to the human body.Hence,driving soft miniature robots using magnetic fields holds great potential for a wide range of applications.Firstly,a three-dimensional Helmholtz coil driving system and a permanent magnet driving system were designed based on the different motion modes of soft robots.The magnetic fields were analyzed using the multiphysics COMSOL finite element simulation software,and the relevant mathematical models were validated.The design and fabrication of the three-dimensional Helmholtz coil driving system and the permanent magnet driving system were completed.The designed threedimensional Helmholtz coil driving system generates controllable uniform magnetic fields,oscillating magnetic fields,and rotating magnetic fields in three-dimensional space by independently controlling the currents in each coil.The permanent magnet driving system is capable of generating gradient magnetic fields and rotating magnetic dipole fields in arbitrary directions within the space.Furthermore,a multimodal soft robot driven by magnetic dipole fields was designed.The robot is constructed using hydrogel and magnetic silicone gel materials.The hydrogel material is composed of gelatin and chitosan,and its mechanical properties were enhanced through the Hofmeister effect.The mechanical performance of the hydrogel was experimentally validated.The trunk of the robot is made of hydrogel and can carry drugs for controlled release.The feet are made of magnetic silicone gel material and are driven by the applied magnetic field to enable robot locomotion.By applying different magnetic fields,the robot can perform three different modes of motion: inchworm motion,rolling motion,and creeping motion in confined spaces.The design of the robot was optimized using ABAQUS finite element simulation software to validate its turning capability in narrow spaces.The motion performance of the robot in different modes was experimentally validated.Lastly,a biomimetic jellyfish soft robot with a double-layer structure was investigated.The lower layer of the robot was made of magnetic silicone gel material,serving as the driving layer that responds to external magnetic fields.The upper layer was made of adhesive hydrogel,possessing adhesion capabilities.By guiding the robot using magnetic fields,it can reach the target location and anchor itself,enabling targeted drug delivery and wound dressing functionalities.COMSOL finite element simulation was employed to analyze the motion performance of the biomimetic jellyfish robot in a fluid environment.The simulation results showed that the robot had a cutoff frequency of9 Hz,and its maximum velocity under a 10 m T magnetic field driving was 12.7 mm/s.Furthermore,an experimental platform for the magnetic driving system was built,and speed testing experiments as well as obstacle traversal experiments were conducted on the biomimetic jellyfish robot,validating the results obtained from the simulation analysis. |
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