Research On Dynamic Characteristic&Controlling Means Of Simulated Earthquake Vibration Table

Simulated earthquake vibration table serves as an important test equipment and plays animportant role in anti-earthquake study. Through simulation of earthquake environment andspecific vibration experimental scenario, it obtains failure mechanism and various dynamicresponse parameters of some equipment, facilities, and structions in conditions of earthquake orspecific vibration, providing experimental evidence and raw data to studies of anti-earthquakeperformance improvement. Therefore, researching and developing high-precision simulatedearthquake vibration table, improving its dynamic characteristics and response precision, andrevealing earthquake or specific vibration status, are fundamentally important research projectand own enormous applicsation value and theoratic significance.This thesis, with2m×1.5m polarity reversal and monodirectional vibration earthquakevibration table as research object and with control theory as research methodology, conductsprofound research on key issues of dynamic performance testing, system modeling,three-parameter controlling technology on the basis of velocity positive regeneration feedback,iterative learning control theory, and other vital technologies. As a consequence it obtains thefollowing creative achievements.1. On the basis of system modeling and dynamic performance testing, the thesis analyzesthe system features of servo-control vibration table at electro-hydraulic place, and reveals theconditions of improving vibration table features and reappearance of earthquake waves, namelybroadening service band, eliminating loading change’s influence on vibration table features,increasing system’s subsidence ratio, and realizing acceleration control.2. According to the feature that the resonance frequency of vibration table’s oil column ishigh and close to90°phase shift frequency of servo control which has a small interval, the thesisconcludes three-parameter contrl thchnology on the basis of velocity positive regenerationfeedback, leading to reduction of oil column resonant frequency, increase in open-loop gain andsystem damping ratio. As a result it attenuates system resonance peak effectively as well asimproves the system dynamic response precision.3. The thesis completes the design of three-parameter marker oscillator, realizing direct controlling of acceleration signal. Through reasonablly deploying status variable’s feedback gainof closed-loop system, loading change’s influence on vibration table features is eliminated.Through adjusting controlling variables of three-parameter marker oscillator, compensation tothe three-parameter marker oscillator is realized. Real test result reveals that workingfrequentcy band is considerably broadened, harmonic component is effectively constrained anddistortion factor of the waveform is reduced.4. Based on iterative learning control theory, the thesis, in accordance with electro-hydraulicservo system bearing nonlinear system’s track control problem, proposes a methodology adopingiterative learning control, builds both digital and analogic control means, constructs digitalcontrol hardware platform, and completes control software development. Experiment reveals thatoffline iterative learning control arithmetic has good astringency, is able to effectively optimizesystems’s dynamic response features, and reduces waveform distortion caused by reasons likesystem non-linear and so on.