Motion Mode Design And Application Of Magnetically Controlled Micro-robot In Magnetic Field

Micro-robots are an important branch of robotics with promising biomedical applications for targeted therapy,micro-manipulation,micro-machining,and minimally invasive surgery.The development of micro-robots is inseparable from the joint development of materials science,biology,engineering and computer science.In the past decades,micro-robots have undergone various developments from rigid to microflexible structures,from open-loop to closed-loop control,and from individual to cluster.In practical application scenarios,in the face of complex and changing environments,flexible robots are able to accomplish more medical actions in human internal cavities and are less likely to cause damage to tissues.Micro-robots at the microscopic scale can be used for cell-related micro-manipulations.The drive of the robot is currently widely used is magnetic field drive,low-frequency and low-intensity magnetic field can penetrate biological tissues well without causing harm,and can drive the micro-robot wirelessly.In this project,micro-robots were studied at millimeter and micron scales.Thin films made of silica gel mixed with magnetic particles(PDMS)were used at millimeter scale,cut and magnetized to assemble a quadrupedal micro-robot,which was manipulated using a uniform magnetic field.The motion mode of the quadruped robot was first analyzed to elaborate its motion process and to test the effect of its motion speed with respect to magnetic induction intensity,frequency and cone angle.In order to test the motion of the miniature robot experiments were also set up with multiple steps with human stomach model as a complex scenario,and by adjusting the magnetic field parameters,the robot can be controlled to go over a variety of complex obstacles.Finally,the handling of items was realized,and the grasping and releasing of items were achieved by changing the cone angle of the conical magnetic field.The use of a special magnetic particle of iron tetroxide with a diameter of about 2μm containing specific antibodies that bind to human T cells at the micrometer scale is an important object of research in targeted therapy.A set of gradient magnetic field manipulation equipment was built for this magnetic particle,and the parameters configured to generate the desired magnetic field were determined by simulation.The actual test results of the finally assembled equipment were consistent with the simulation results,and the maximum magnetic induction strength of the magnetic pole surface reached over 200 m T when 5A current was applied.The magnetic field gradient is used to pull the magnetic particles to move in a directional manner,which can be controlled to go out of the four trajectories of "SIAT".The relationship between the speed and the driving current is tested in the experiment,and it is proved that the speed of the magnetic particles can be changed by the current.Finally,after binding the magnetic particles to the T cells,they are guided through a barrier by a gradient magnetic field.