Research On Key Technology Of Electromagnetic Drive Of Magnetic PVA Hydrogel Soft Robot

Soft robot is an important research content in the robots'field.It has the characteristics of flexible movement,high degree of freedom,and strong environmental adaptability.It is widely used in medical,biological engineering and military fields.The smart hydrogel is a typical smart flexible material with high water content,softness,strong mechanical properties and good biocompatibility,and can be used as an ideal soft robot base material.In this thesis,the self-developed Fe₃O₄/PVA magnetic hydrogel,used as the base of the soft robot,is taken as the object;a driving method of soft robot combined coil external magnetic field is studied.First is to prepare the Fe3O4/PVA magnetic hydrogel and analyze its performance.The Fe₃O₄/PVA magnetic hydrogels with different composition ratios were prepared by freeze-thaw method?one of the hydrogel physical cross-linking methods?.Through the study of the properties of magnetic hydrogels doped with different content of Fe3O4 particles and different freeze-thaw times,a magnetic hydrogel with good swelling properties,mechanical properties and magnetic properties was obtained as the base material of the soft robot.Secondly,the external magnetic field driving theory of the magnetic soft robot is studied,the principle of the Helmholtz coil and the Maxwell coil to generate a magnetic field is analyzed,and the mechanism of the uniform gradient magnetic field generated by the combined coil is studied.The conclusion is that the spatial combination of Helmholtz coils and Maxwell coils can generate gradient magnetic forces and magnetic torques that drive soft robot.Finally,on the basis of theoretical analysis,the combined coil model was designed,and the magnetic field of the combined coil was simulated by using ANSYS finite element analysis software.The simulation results of the two coils were consistent with the theoretical analysis,thus verifying the reliability of the built mathematical model.Through the calculation and analysis of the magnetic field of the combined coil,it is obtained that by adjusting the load current of the Helmholtz coil and the Maxwell coil in the combined coil and the relative position translation of the pipeline where the soft robot is located,the required gradient magnetic force and magnetic torque that drive the soft robot can be get,which can realize the autonomous movement of the magnetic soft robot.