Research On Magnetic Field Correction And Control Method For Micro-nano Robot Operation

Magneto-controlled micro-nano robot is a kind of micro-nano scale robot that moves under magnetic field,which has been proved to be a tool for in vivo targeted therapy.Because of its good controllability,biocompatibility and other advantages,it has been widely concerned in the field of biomedicine.The position control and motion control of the magneto-controlled robot are one of the keys to ensure its completion of tasks.However,there are still some problems in the magnetic field driving control of the micro-nano robot,which are mainly reflected in the control accuracy affected by the nonlinear hysteresis characteristics and time-varying characteristics of the electromagnet coil.Therefore,the magnetic field correction and control methods of micro-nano robots are studied in this dissertation to solve the above problems.The specific contents are as follows:In order to solve the problem of nonlinearity caused by hysteresis of electromagnet coils,a method of dimensionality reduction least square support vector machine(LSSVM-DEIM)is proposed in this dissertation,and the hysteresis is estimated and the compensator is constructed.The purpose of linearizing the nonlinear system is realized by constructing compensator.In this dissertation,the number of least squares support vector machine operators is reduced from 3000 to 35,and the effectiveness of this method for estimating hysteresis is verified by experiments.To solve the problem of time-varying model caused by heating of electromagnet coil,an adaptive model predictive controller(MPAC)is proposed in this dissertation to realize the control of time-varying system,and the stability of the adaptive model predictive controller is proved.In this dissertation,the control accuracy of MPAC is compared with other controllers(MPC,PID)at different temperatures and different frequencies,and the superiority of MPAC algorithm for magnetic field control of electromagnet coil is proved.Aiming at the kinematic modeling of the micro-nano robot,a mathematical model describing the rotational motion of the micro-nano robot is constructed based on electrodynamics and fluid force,and the rotational motion of the micro-nano robot is predicted.In this dissertation,a visual algorithm is used to detect the rotation speed of the micro-nano robot,and the theoretical speed based on the model is compared to verify the validity of the mathematical model.Based on the modeling and parameter estimation of the driving magnetic field of the magneto-controlled robot,this dissertation realizes the precise control of the magnetic field of the electromagnet coil.This method can not only provide a driving control method for the magneto-controlled robot,but also be extended to other electromagnet field correction and driving control scenarios.