Control Strategy Of High Accurcy Sinusoidal Vibration For The Hydraulic Shake Table

Sinusoidal vibration experiment technology is one important aspect of vibration mechanism environment simulation, which is widely used in engineering areas as defense, aerospace, construction. Sponsored by'great imitation and simulation equipment and its key technique research'of the 2nd phase of'985', this paper carried out theoretical and experimental research on key control strategy of sinusoidal vibration, attaining the purpose of improving the output precision of sinusoidal vibration experiment, which is significant to sustain feasibility and credibility of sinusoidal vibration experiment.Hydraulic shake table is important equipment for implementing large, full-length specimen sinusoidal experiment. For its nonlinearity and uncertainty of experiment conditions, the actual response waveform of hydraulic shake table acceleration is seriously distorted, with ill amplitude stability, bigger amplitude attenuation and phase lag. These problems lowered the credibility of results of sinusoidal experiment, even made the experiment impossible.In order to implement high accuracy sinusoidal vibration experiment, on basis of analyzing theories concerning adaptive filter, adaptive amplitude-phase controller and adaptive harmonic canceler were designed, and experiment was performed on custom servo-controller. Research of this paper includes the following:The servo-controller based on DSPs is developed for implementing the control algorithm of vibration experimental system. Through a series of pre-work design based on hardware and software, the model-based design of control system is accomplished for the custom DSPs controller. By this means of software design, the control algorithm code could be generated automatically by the Simulink model instead of hand-writing, providing the convenient implementation of design and debugging of control algorithm in this thesis.For eliminating the phase lag and amplitude attenuation of acceleration response and improving the amplitude stability, the control strategy of adaptive ASLMS-based amplitude-phase control is proposed, as well as its principle analysis. After comparing with amplitude-phase control strategy based on the standard LMS, the proposed amplitude-phase control strategy makes the parameter access easier, convergence faster, and the misadjustment smaller.The control strategy of adaptive ASLMS-based harmonic cancellation is proposed for eliminating the higher harmonics of acceleration response. For implementing this strategy, the filter structure of adaptive harmonic canceller (AHC) eliminating multi-harmonics simultaneously is proposed, which does not increase the amount of calculation, comparing with the traditional AHC eliminating single harmonic. Experimental research comparing with AHC based on standard LMS, demonstrated that ASLMS-based AHC, which has faster convergence and smaller distortion, owe more advantages in the parameter setting.