IMPEDANCE CONTROL METHOD OF STEPPED SWEPT SINE VIBRATION TEST BASED ON PERIODIC EXTENSION

The discontinuity between two adjacent sine signals and the poor control precision are two di-cult problems in the multiple input multiple output (MIMO) swept sine vibration test. This paper proposes a new method to smooth the discontinuous signal segments of sinusoid waves at difierent frequencies, to guarantee the test time requirement and the phase tolerance requirement of the reference. The compression impedance control method (CICM) is proposed to solve the over correction problem of the excited signals. The impacts on the rate of convergence and the control precision are analyzed, and the threshold of the frequency response function matrix (FRFM) is set to avoid the over excitation of the singular FRFM at some special frequencies. Finally the paper establishes the test conditions for the multiple axis vibration test, and tests the algorithm for the multiple axis swept sine test. It is shown that the amplitude and phase responses could be controlled within the tolerance range of the reference values by the 5 times correction, when the compression factor value is 0.4, and the control algorithm is shown to be reliable.