Digital Control Test Rig Of Five Degree Of Freedom Electric Spindle Based On AC Hybrid Magnetic Bearings

Magnetic bearing is one new type of high performance bearing which suspends the rotor in a contact-free manner.As it has many advantages as no friction and abrasions,lower power consumption,high speed,high precision and long service life,etc,it becomes more and more useful in many areas.A new-style AC hybrid magnetic bearing(HMB) is proposed in the dissertation.Compared with the traditional DC magnetic bearing,the AC HMB has many advantages,such as compact configuration,low cost,convenient driving and control,etc. Supported by National Natural Science Foundation of China(50575099),the digital control technology on AC HMB electric spindle system has been studied in the dissertation.The detail contents are as follows:Firstly,the unitary structure of five degree of freedom(DOF) electric spindle is introduced, the operation principle of the AC HMB is expounded,the structure of AC-2DOF-HMB and AC-DC 3DOF-HMB are analyzed and the expressions of suspension forces are deduced.On this basis,the state equation for five DOF electric spindle is built.Secondly,the PID control strategy and fuzzy PID control strategy are researched.By integrating the advantages of the PID control and fuzzy PID control,the parameter self-tuning fuzzy PID is designed.Use the axial HMB be the object of study,the simulation experiments are completed using MATLAB software,the results are analyzed and compared.Thirdly,the control block diagram of five DOF electric spindle control system is introduced, the hardware of the digital control system is developed based on TMS320F2812 DSP and the sections of the hardware are described in detail.The software of control system is developed using C language and assemble language in the C2000 development environment,the flow chart of the software is described and the programs of each function module are developed.Finally,based on the experiment object of the radial AC-2DOF-HMB,the integrated test rig has been constructed according to the designed digital control system.Many tests,such as rotor floating tests,static suspending tests,anti-interference tests,and so on,have been completed,and experiment results have been analyzed.