Study On Thermal Compensation Control Method Of Giant Magnetostrictive Brake

With the development of precision positioning technology,more and more fields begin to study how to use precision control technology in the field of engineering.Giant magnetostrictive material(GMM)has the advantages of large strain,high controllable precision,and large magnetostriction coefficient,and is an important material for developing precision actuators.However due to the existence of hysteresis loops,non-linear expansion and contraction,and eddy current effects in the can cause problems such as long adjustment time and instability in the control process.The Giant Magnetostrictive Actuator(GMA)made of a giant magnetostrictive material is a mechanism capable of microdisplacement driving.This paper takes GMA as the research object,establishes the hysteresis model and combines adaptive control algorithm to study the micro-displacement control of GMA.The main content of the paper:The first chapter introduces the background of precise positioning,explains the significance of controlling GMA,and describes the characteristics of and its application at home and abroad.The second chapter introduces the positive effect mechanism of the specific theory of elongation and the working performance of GMA,the matters that should be paid attention to in the development of GMA,and the design method of the coil in GMA.The third chapter,the hysteresis loopback modeling of GMA is introduced.The internal magnetic field changes of GMA are explained by JA model.The hysteretic displacement output model is established,the parameters to be identified are given and the parametric model is identified by hierarchical genetic algorithm.Analysis of identification data under different conditions.The fourth chapter,introduces the design of GMA control system,adaptive control of GMA by LMS algorithm and proposes an improved variable-step LMS algorithm to improve the control system,and improve the response speed in the control process through the improved variable-step LMS algorithm.The fifth Chapter,the GMA control system is set up to measure the displacement under different current and prestress conditions.The improved LMS algorithm controls the system and compares the magnetostrictive displacement control accuracy under DC and AC.By comparing the Sigmiod function LMS algorithm with the modified variable-step LMS algorithm,the response speed is improved in the control process,and the control accuracy reaches the ideal displacement accuracy.