Research On Rigidity Control Of Large-scale Machine Tool Maglev Platform

This thesis is based on Liaoning province education department project "Research on maglev linear motor and its control strategy for machine tool feeding system", advising the practical characteristics of large-scale machine tool, that the working platform of large-scale machine tool requires more strictly on suspension rigidity than the maglev train. This thesis did research on control algorithms to improve the maglev rigidity.As hybrid magnets combined permanent material and electrical magnet can solve the problem that the traditional electrical magnetic suspension system consumes much power, This thesis mainly did research on hybrid magnets.At the first, in order to resolve the rigidity effect caused by the current changes of electromagnet coils, double loop control system was adopted. Then the thesis introduces some common controllers, and choose PI controller after comparing them. The current inner loop not only improves the dynamic characteristics, but also offset uncertainty and change. The main work of the thesis is to choose and design outer loop controller by analyzing characteristics of traditional PID algorithm and Fuzzy algorithm, Fuzzy-PID algorithm was proposed. The composted control model based on the conventional PED regulator employs fuzzy reasoning and accomplishes PID parameters self-tuning according to different error and change rate of error, thus perfect performance can be reached.At last, the thesis simulates the above three control systems, and analyzes the feasibility according to practical application. The simulation results prove that the Fuzzy-PID controller not only improves the suspension rigidity of hybrid magnets system, but also offsets the error, so it is suitable for large-scale machine tool's requirements.