Research On Structure Design And Zero Power Control Method Of Hybrid Magnetic Levitation Platform

In the production process of precision products such as chips and semiconductors,the traditional transmission system has friction and wear,and the dust and other pollutants generated will seriously affect the manufacturing accuracy and yield.Magnetic levitation technology has the characteristics of no friction,no lubrication,no contact and so on,It can be applied to the dust-free transmission workshop,which can effectively reduce dust pollution and increase the production accuracy and efficiency of products.Under the eccentric load condition,the hybrid magnetic levitation system adopting the magnetic pole movable type has the same air gap at each magnetic pole after stable suspension,and the current in the electromagnetic coil tends to zero,so that the power consumption of the system is effectively reduced,and meanwhile,the problem that suspended objects incline is solved.In this thesis,the hybrid electromagnet structure and the magnetic pole rotation structure were analyzed and designed.The stable suspension air gap and suspension weight of the hybrid electromagnet were analyzed by finite element simulation.The influence of air gap and current on leakage flux was further obtained by analytical method and finite element method.According to the principle of magnetic field segmentation,the theoretical magnetic mathematical model of hybrid electromagnet was established.The suspension force simulation analysis and force measurement experiment of a single hybrid electromagnet were carried out.The modified magnetic mathematical model was established by introducing the correction coefficient,which was consistent with the actual magnetic force measured by experiment.The dynamic model of the system was established by analyzing the force of the suspension disc,and the LPV model of the system was further established by considering the relationship between the coefficient matrix of the model and the moving angle of the magnetic pole.According to the zero-power level suspension condition that the current in the coil tends to zero and the air gap at each magnetic pole reaches the same,the relationship between the centroid position of the suspension disk and the moving angle of the magnetic pole was analyzed,and the magnetic force acting area was determined to be a circle.The suspension controller of PD,optimal and fuzzy PD was further designed,and zero power control was realized by current integral feedback.Loaded at any position,the system can achieve stable suspension under the action of the PD controller and the current in the electromagnetic coil tends to zero.Set the parameters of the three controllers and conduct unbalanced load simulation analysis,and the stability and response characteristics of the three controllers were compared.Aiming at the problem that the suspension disc was suspended in an inclined state under unbalanced load conditions,an anti-tilt controller was designed.The simulation results show that by adjusting the magnetic pole angle,the stable suspension current tends to zero and the air gap of each magnetic pole is the same.Build a hybrid magnetic levitation platform prototype and experimental system.Firstly,the suspension and position step experiments were carried out.The experimental results show that the air gap of each magnetic pole of the platform is the same,and the current is not zero,after 1.14 seconds,the platform realizes suspension.Secondly,based on the PD suspension controller,the current integral feedback was introduced to carry out zero power floating experiment,air gap external disturbance and unbalanced load disturbance experiment.The experimental results show that the current tends to zero after the stable suspension of the platform can reduce the system power consumption,and the platform has better stability under external disturbance.Finally,the anti-tilt experiment was carried out by joint adjustment the air gap integral feedback and magnetic pole movement,and the zero power experiment in which the magnetic pole does not move was compared.The experimental results show that the air gap of each magnetic pole is the same and the current tends to zero after stable suspension by moving the magnetic pole at a certain angle,the average power of each magnetic pole is less than 1W,which effectively reduces the power consumption of the system and solves the problem of suspension disc tilt.