The Study On Electromagnetic Actuation Characteristics Of Magnetic Hydrogel

Due to the increasing demand for soft grasping operation in micro space,coupled with the sudden COVID-19 in recent two years,the remote controlled flexible robot industry has developed rapidly.At present,it has become a difficult and hot spot in the field,and the remote driving control mode is also very diverse.Among them,magnetic drive has the advantage of high driving efficiency,good biocompatibility of magnetic materials,easy access and relatively safe medical use,which makes it a leader in this field,and it adopts magnetic hydrogel with response characteristics and multiple properties as the matrix material of flexible robot.As the result,magnetic hydrogel is taken as the research object in this paper.In view of the difficulty and hot spot of remote control of magnetic hydrogel,the electromagnetic actuation characteristics of magnetic hydrogel are studied by using the driving force of oscillating magnetic field.Firstly,the motion theory model of magnetic hydrogel is abstracted from the motion characteristics of microorganism in nature,and the basic motion mechanism of magnetic hydrogel under low Reynolds number condition is given.Based on this theory,the significance of non-reciprocating motion for the effective movement of magnetic hydrogel microsegments at low Reynolds number is studied.Secondly,the two-dimensional magnetic field with iron core solenoid is simulated and analyzed by Maxwell finite element method,which analyzes the effects of current,solenoid shape distribution,core relative permeability,core outer diameter and core fillet on the magnetic field distribution at the same time.On this basis,the Helmholtz coil is designed,which helps to analyzes the magnetic field uniformity on the axis of circular and rectangular coil,and selects the rectangular coil to build an oscillating magnetic field that generates driving force.Finally,the magnetic hydrogel was prepared by freeze thaw method and its magnetic properties were analyzed by experiments.Experiments show that the magnetic hydrogel can simulate the bending movement of fingers and achieve the action of"tension"well under the control of static magnetic field.The relationship between Fe₃O₄concentration,magnetic field intensity and deflection angle,and the relationship between Fe₃O₄concentration and magnetic field threshold are obtained by analyzing the experimental data.In this thesis,the dynamics model of the flexible flagellum micro robot’s oscillation and the oscillation characteristics are analyzed and demonstrated which is applied to magnetic hydrogel driven by oscillating magnetic field in viscous medium to analyze the effect of oscillation frequency on material excitation characteristics.