基于周期延拓的步进式正弦扫频阻抗控制方法

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

针对步进式多输入多输出正弦扫频振动试验中相邻信号过渡不平顺以及多点相位控制精度差的问题,分析扫频频率切换机理,在保证试验时间以及多点相位差满足参考容差要求情况下,提出周期延拓法平稳地处理两段不连续信号;提出了阻抗多点控制算法,分析了压缩因子对收敛速度与控制精度的影响,设定频响函数矩阵条件数阈值以避免结构病态频率带来的过激励影响;开展多轴多点正弦扫频振动算法试验,结果验证了算法可靠性与有效性.

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 di?erent 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 the5times correction,when the compression factor value is0.4,and the control algorithm is shown to be reliable.