Abstract: In multi-exciter/multi-axis (MEMA) vibration control tests, it is frequently difficult for the auto-spectra of the control point responses to achieve the required reference targets at the frequency points where the frequency response function matrices are ill-conditioned. To cope with this problem, a new method is proposed in this article. The pre-compensator of the plant is obtained by curve fitting and modifying of the frequency response functions in a specified frequency range. The exciting spectrum matrix is then shaped via H_∞ loop-shaping theory. The shaped exciting matrix is used in the control loop computation instead of the original one. The experiment shows that the modified algorithm via loop-shaping design is capable of suppressing the adverse effect of the frequency response function at some specific frequencies. The auto-spectra of the control point responses are improved and become satisfactory.

Key words: loop-shaping design, multi-exciter/multi-axis, vibration test, vibration control, multi-input/multi-output