Research On Motion Mechanism And Control Strategy Of Magnetorheological Fluid Robot

Magnetorheological fluid robot(MRF robot)is a spherical magnetic control robot designed with magnetorheological fluid(MRF)as the magnetic control object and utilizing the magnetization characteristics of MRF.The MRF robot has the advantages of simple structure,rapid response to external magnetic fields,light weight and strong controllability,it has great application potential in medical fields such as targeted drug delivery and treatment in vivo.Aiming at the problems of unknown movement mechanism and complicated control of the MRF robot,the paper conducts research from the following aspects:(1)The magnetization characteristics of the MRF are introduced.The two MRF robot design schemes based on driving modes of magnetic torque and gradient magnetic field force are proposed.Two design schemes were simulated and the magnetic torquedriven robot was identified as the final design scheme.Explore the motion mechanism of MRF robot from the dynamic characteristics and magnetic moment mechanics model.(2)The basic theory of Helmholtz coils and the principle of generating rotating magnetic fields are introduced.The design parameters of the 3D Helmholtz coil are obtained.Finite element simulation analysis of the coil model is performed.The coil is processed and its performance is tested using a Gauss meter.Motion speed detection method of MRF robot based on image processing is proposed.The MRF robot motion experiments are carried out.(3)Based on the characteristics of the MRF robot's motion speed control,the PID control strategy is proposed and the PID controller parameters are tuned using conventional PID,gray wolf optimization algorithm PID(GWO)and improved gray wolf optimization algorithm(IGWO)The unit step response simulation analysis of the controller is performed.The simulation results show that compared with the conventional PID and GWO PID controller,the IGWO PID controller has faster response time,shorter time to reach the target state and no overshoot.The IGWO PID controller has better control performance.(4)The MRF robot control experiment bench is built.The hardware configuration of the test bench is introduced and the host computer is designed with LabVIEW.The experiments of motion speed stability control of the MRF robot are carried out.The experimental results show that compared with the conventional PID and GWO PID controller,the IGWO PID controller has better control effect.There are 52 figures,6 tables and 93 references in this paper.