Research On Characteristic Analysis And Inverse-model Compensation Of Heavy-load Mutti-modal Electro-magnetic Exciter

The performance of turret and other military equipment plays a decisive role innational defense construction, but they usually work in harsh external environmentand complex conditions, and are subjected to strong vibrations, which would cause avariety of problems, such as the damage of sight, the loosen or broken of fasteners,the wear of parts or fatigue failure, etc. These problems would influence the shootingaccuracy, even bring accidents or disable the equipment. Therefore, it is necessary tocarry out vibration tests to forecasting the potential problems, thus achieving reliabledesign and optimized design. However, the research on heavy-load militaryequipment exciters could not keep up with the need of national defense in a longperiod, which seriously restrained the modernization of China’s defense construction.To improve this situation, this paper designs a vibration system which can testheavy-load military equipment. Considering the characteristics of heavy-load andlimited space, a system which combined hydraulic excitation with electromagneticexcitation is proposed, and the hydraulic exciter is used to offer the large amplitudevibration below50Hz, while the electro-magnetic exciter is responsible to the smallamplitude vibration in the frequency range above50Hz. Here the electro-magneticpart is mainly discussed.At the beginning of the research, we got an understanding about thecharacteristics, development status and application prospects on heavy-load exciterthrough relevant literature. According to the requirement of a turret vibration testplatform, as well as the virtues, defects and application occasions of different exciters,an overall vibration program which combines hydraulic excitation withelectromagnetic excitation is adopted, and the multi-modal structure is proposed toamplify the amplitudes. Based on an existing electromagnet, a resonance mechanismis designed by theoretical calculation and finite element static analysis and modalanalysis according to the working principle of electromagnetic exciter thus finishedthe structural design of experimental device. Through electromagnetic analysis inAnsys got the static suction characteristics. Using Matlab/Simulink established themathematical model in circuit, magnetic and mechanical moving parts, while there are nonlinear factors in electromagnetic system, and the mechanical part is a multi-modalsystem, and the dynamic characteristic of the device is analyzed by simulation.To avoid the excessive fluctuation of output waveform, the inverse-modelcompensation control method is proposed. Different inverse models are establishedbased on the specific system, and the effectiveness of the inverse-model control isanalyzed by simulation results, then get the conclusion that such control method isuseful in compensating the amplitude in resonance region, and the output can keep upwith target signal well. By changing parameters in inverse model observe theirinfluence on result, which could be the foundation of parameter correction in thefuture. A DSP application system is designed based on TMS320F2812, and thecontrol algorithm of the inverse model is written into DSP by Simulink’s automaticcode generation technology combined with the code development and debuggingfunction of CCS. The sweep-frequency experiment indicates the existence of multi-modal in the device, and the parameters are revised according to the result. Theinverse-model experiment verifies the effectiveness of this control method on theresonance frequency characteristic in the main modal.