Research On Control Algorithms For Flexible Maglev Rotor

Magnetic bearing system uses controllable electromagnetic force to levitate therotor without contact, which is a typical open-loop unstable system. Therefore,effective and reasonable control algorithms must be adopted in order to ensure itsstable operation. Currently, with rotating mechanical rotors developing to thedirection of high-speed and high accuracy, requirements of mechanical structure andperformance are further improved and researches have changed from rigid magneticbearing system to the flexible one. However, the vibration amplitude of flexible rotoris too large when approaching or over the critical speed, which will easily lead tosystem damage, hence appropriate control algorithms must be taken to suppress thevibration of flexible rotor. Therefore, researches on control algorithm of flexiblemagnetic suspension rotor have important practical significance.Firstly, working principle of magnetic suspension system was introduced in thispaper, and electromagnetic force expressions of the system were deduced. Then eachcomponent of mechanical structure and control system in the magnetic bearingsystem was described in detail, and the equivalent stiffness and equivalent dampingwere calculated as well.Secondly, virtual prototyping technology was introduced briefly and main stepsto establish a joint simulation model were described. Then the flexible body theory ofADAMS/Flex was introduced. The natural frequency and mode shapes of the flexiblerotor were analyzed. Moreover, the joint simulation model of the flexible rotor basedonADAMS and MATLAB was established.Finally, the simulation of control algorithms was carried out on the case that theflexible magnetic suspension rotor was supported on one degree of freedom in thevertical direction. For three working states of the flexible rotor, stationary suspension,low-speed rotation and high-speed rotation, the PID controller, Fuzzy PID controllerand single neuron adaptive PID controller were designed. Moreover, the simulationcurves of the flexible rotor under three working states were respectively obtained.The analysis results show that vibration of the flexible rotor can reduced by changing control algorithms, making it crossing the critical speed，and the best is single neuronadaptive PID controller.Research work in this paper can provide some references for that flexible maglevrotor crosses the critical speed smoothly. The purpose to improve the supportcharacteristics of the flexible maglev rotor system by designing the control algorithmwas achieved, which provides some technical support for the wide applications ofmaglev system in high-end equipments.