Research On Active Disturbance Rejection Control Method For Magnetorheological Impact Buffer System

Magnetorheological(MR)damper,as a semi-active control device,can adjust the output damping force in real time according to the change of excitation current.In the field of low-speed vibration reduction,the inherent hysteresis characteristics of MR damper and the influence of temperature on damping force are not obvious,which has not attracted the attention of researchers.However,in the field of impact buffer,the working environment of MR damper is very complex,the hysteresis characteristic caused by the rapid change of the control current makes the system unable to obtain the ideal buffering effect.Moreover,in buffering process,the rapid rise of temperature will reduce the damping force of the system output.In addition,the unmodeled part of the system will also affect the output of the system damping force and so on.For the control system,the above phenomena can be classified as the internal or external disturbance of the system.These factors seriously affect the buffer performance of the system.Therefore,it is urgent to analyze the disturbance factors of MR Impact Buffer System and put forward the disturbance suppression control strategy.The research goal of this subject is to suppress or eliminate the influence of the disturbance in the MR Impact Buffer System through control methods,so as to achieve the ideal buffer effect of the system.It mainly uses the methods of theoretical analysis,modeling and simulation and experimental verification to deeply study the disturbance factors of the system and the antidisturbance control strategies.The main research contents include:(1)According to the working principle and control objective of the MR Impact Buffer System,the effects of system model uncertainty,unmodeled part,temperature and hysteresis on the system are analyzed.The corresponding disturbance curves are established according to the temperature rise model and hysteresis curve,which lays a solid theoretical basis for numerical simulation and experiment.In order to prove disturbance is an important factor that makes the system unable to achieve the expected buffer effect,two groups of PID control systems are designed,the difference is whether to input disturbance signales.(2)According to the active disturbance rejection control principle and control objective,the Continuous Terminal Sliding Mode Control(CTSMC)law,Active Disturbance Rejection Control(ADRC)law and Sliding Mode Active Disturbance Rejection Control law are designed,a MR Impact Buffer System including temperature and hysteresis disturbances is built in Simulink,and the suppression effect of the proposed control strategies on the disturbance are analyzed.Taking the ideal adjustable Coulomb damping force as the input of the system,the hysteresis and temperature(20～50℃)disturbance curves are input to the system,the numerical simulation results show that the MR Impact Buffer System with Sliding Mode Active Disturbance Rejection Control strategy obtains the minimum peak damping force(4350N)within the allowable buffer displacement range,that means the Sliding Mode Active Disturbance Rejection Control method proposed in this paper has a significant ability to suppress the disturbance,and has advantages in the cushioning performance of MR impact cushioning system.(3)According to the signal range collected by the sensor and the requirements of real-time control,the MR impact buffer real-time controller based on STM32F103zet6 chip was designed and manufactured.As for the hardware part,the conditioning circuit of serial communication,LCD liquid crystal display,five channeles acquisition signal and the PWM wave boost conditioning circuit output by the controller were designed.As for the software part,the programming of control strategies were completed.(4)The MR Impact Buffer System based on em WIN is designed and built.After the control algorithm is selected through the LCD screen,the corresponding buffer effect will be displayed on the screen in real time.When the Sliding Mode Active Disturbance Rejection Control is adopted,the buffer curves of the test and simulation results are generally consistent,which shows that the design of Sliding Mode Active Disturbance Rejection Control algorithm and real-time controller is reasonable.