Design Of Control System For Magnetic Bearings Based On Embedded RTOS

Active magnetic bearings (AMBs) make rotor suspended by magnetic force. Since AMBs have many advantages of no friction, no abrasion, no lubricated, lasting life, maintenance-free to the traditional bearings, they are attracting more attention gradually. However, in addition to the part of the machine, the control system is very important for AMB system, the nature of it affects the dynamic performance of AMB system and control precision of the rotor. Taking five-freedom-degree AMB as research object, the digital control system of AMB, based on the Embedded Real Time Operation System (RTOS), is studied in this paper. By means of the DSP chip and DSP/BIOS software structure, the advanced control hardware plan is made, and the traditional algorithm and the multimode intelligent control algorithm are discussed. The main contents of the paper are listed as follows:The structure and the relation of five-freedom-degree AMB are described in detail. By the principle of the Electromagnetic Theory, the electromagnetic force expressions are deduced from the model of the single-freedom-degree AMB. Further more, the control model of the five-freedom-degree has been established.According to feature and designing desire of AMB, the DSP hardware plan is made, with the peripheral equipments of grouping DA, SCI, CPLD, etc. The hardware plan solved the harmonious control problems of the traditional distributed hardware plan, improved the stability and reliability, simplified the system's structure, and reduced the system's price.The study of AMB control algorithm has been developed. The continuous PID and the PID have been set up. Based on the control model of the single-freedom-degree, the multimode intelligent control algorithm has been discussed on the requirements of the fact to perform the good control of AMB.Due to the complexity of AMB system, the design of the control software is finished based on the Foreground/Background software structure. The C/C++ design theory is brought out. Because of the limitation of the Foreground/Background software, the paper gave the design of the software structure on the Embedded RTOSDSP/BIOS, and the process of how to do it.