Research On LADRC Of Single-Point Suspension System

The constant conduction electromagnetic levitation system itself has strong nonlinearity,and the accurate acquisition of its model cannot be guaranteed under normal circumstances.The traditional control method relies heavily on the accurate model,which makes it impossible to guarantee the control quality of the suspension system.Therefore,the study of single-point electromagnetic levitation control system has important practical significance for the development and application of magnetic levitation technology.Linear Active Disturbance Rejection Control(LADRC)can make the controlled object independent of its mathematical model,thereby overcoming the influence of objective nonlinearity and uncertainty of the system on the tracking effect,and ensuring the stability of the system.At the same time,it is of great help to the enhancement of the system's anti-interference ability.This paper takes the single-point suspension system as the research object,designs a position-current double closedloop controller,and verifies the effectiveness of the proposed algorithm through simulation and experiments.First,the relevant expressions of the single-point suspension system are refined by using theoretical knowledge,and the modeling work is carried out,and the second-order equivalent model is obtained by means of linearization.In order to improve the response speed of the system,a position-current double closed-loop controller is designed.In order to simplify the structural design,the current inner loop adopts simple PI control;in order to suppress the influence of the internal parameter perturbation and external disturbance of the single-point suspension system,the position outer loop adopts the improved LADRC control.Secondly,aiming at the problem that the linear expansion state observer(LESO)cannot adjust the disturbance tracking in time,the original LESO deviation control quantity is optimized based on the original LESO deviation control quantity,and a new deviation control quantity is constructed to control the state quantity respectively.At the same time,the parameter tuning method of the improved LADRC controller is elaborated.The control effect of LADRC and PID controller is compared and analyzed by MATLAB simulation experiment.The simulation results show that,compared with the PID controller actually used by the maglev train,the improved LADRC controller has a faster response speed,better dynamic performance when dealing with sudden disturbances,stronger anti-disturbance ability,and when the model parameters change,showing better robustness.Finally,in order to further verify the effectiveness of the improved LADRC controller,a set of single-point suspension control experimental platform is designed and built.By writing the program on the software platform,the control effect of the designed improved LADRC controller and the PID controller is compared.It can be seen from the experimental results that LADRC has more obvious advantages in the dynamic performance and anti-interference ability of the system.