Research On The Design Of Self-sensing Magnetic Levitation Ball Control System

Maglev technology is an emerging mechatronics technology which is developed in recent years.Along with the development of control theory,related electromagnetic,materials science and other scientific science,maglev technology has also made great progress.Maglev technology gets a very wide range of applications in magnetic bearings and magnetic levitation train.Magnetic levitation system is a basic model of magnetic levitation system.And Magnetic Levitation System is a nonlinear and unstable system,therefore,the study of magnetic levitation system has important significance for promoting the development of maglev technology.Because of the presence of position sensors,magnetic suspension system makes a large volume,dynamic performance deteriorated the development of magnetic levitation technology restricted severely.Therefore,in order to overcome the evils of the sensors,this paper presents a novel magnetic levitation system actuator sensor integrated design.This paper is researched on the magnetic hockey system both theoretically and experimentally.Firstly,according to the kinematic equations and electromagnetism equations of the magnetic levitation system,we build the dynamic model of it.At the equilibrium point of the magnetic levitation system model,we linearize it.Because magnetic levitation system is an unstable system,we must have closed-loop feedback control of position.In order to control levitation ball system stably,at first we design the PD controller to get the system leading correction.And in order to eliminate the steady-state error,then we design a PID controller,and proposes an optimization method based on LQR of magnetic levitation system PID parameters.This method turns the solution of the PID parameter to the solution of the optimal controller based on LQR by extension of the system’s differential equations.By properly selecting the weighting matrices Q and R,we can determine the optimal PID control parameters.And then we proceed simulation studies to verify if the designed PID controller is active.The estimation of position is an important part of the suspension system actuator sensor integrated design,and the key of the position estimation method is to generate a continuous disturbance of the current in the solenoid coil.We use the switching ripple of the bridge circuit which is controlled by PWM to estimate the position,and deduce the electromagnetic model of the levitation ball system,based on this model,then propose a method of estimating positionalgorithm based on the least squares method.This method is estimated the solenoid coil inductance by measuring the current and voltage of the electromagnet coil,and determine the position by a function of the inductor and the air gap of the magnetic levitation system.In order to verify the position estimation algorithm which is proposed,this paper build a test platform of the magnetic levitation system,and then design a magnetic levitation control system based on DSP chip.We design the hardware control circuit and software.It achieves a stable control of the magnetic levitation system,and the experimental results demonstrate that the estimation of position based on least squares method is effective.