Pre-test analysis to reproduce random pressure fields with multi-channel acoustic control

Abstract Pre-test analysis is proposed as a methodology to design control strategies for environmental acoustic tests. In the space industry these tests are used to assess the survivability of hardware, which is exposed to harsh dynamic loads in service. In this work an array of loudspeakers and microphones is used in a laboratory to reproduce the acoustic environment generated during the launch of a spacecraft. Active control is required to design the signals driving the loudspeakers. Pre-test analysis uses an internal model of the electro-acoustic plant responses to automatically design the control parameters required by multi-channel random control algorithms. The outcome of pre-test analysis is the automatic selection of the control microphones, and a set of realizable test references in the form of a spectral density matrix. The methodology proposed in this work to design the control strategies is validated experimentally on system level tests. Compared with other approaches, proper design of the control strategy for the environmental acoustic test significantly enhances the correlation between the measured and desired pressure responses.