| PMAC servo system is widely used in the field of electrical drive due to itsexcellent dynamic performance, accuracy and Tracking characteristic. With theincreasing requirements of application, PMAC servo system needs fasterresponse and higher operation bandwidth. Mechanical transmission devices areused to connect executor with PMAC motor, but its flexibility will bringresonance points in servo system. Resonance points would near or be containedin operation bandwidth as the enlarging of system bandwidth, and lead tomechanical resonance.This dissertation studies characteristics of elastic mechanical transmissionsystems, and establishes the2-mass model. Theoretical analyzes and simulationsof2-mass model are used to study the principle and phenomenon of mechanicalresonance. Then the structure of notch filter is studied, and the effect of eachnotch filter parameter is analyzed. Feasibility and availability of suppressingmechanical resonance with notch filter are confirmed via simulation. Digitalnotch filter is achieved using equivalent discretization method, and analyzed itsperformance. Identification methods of system frequency characteristic arestudied in order to achieve the online mechanical resonance suppressing. Fourdifferent identification methods are analyzed and compared, and the method thatanalyzes current directly is used to obtain the resonant frequency online. FFTprogram that used to identify frequency characteristic is accomplishedconsidering the operational capability of MCU.Experimental platform is designed based on2-mass principle andmanufactured. Experiments confirm the effect of online mechanical resonancesuppressing. |
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