Publications Details

Exploring uncertainties in multi-input-multi-output (mimo) testing

Woodall, James; Hossain, Maimuna; Maji, Arup; Pott, John; Moreu, Fernando

Multi-Input-Multi-Output (MIMO) testing enables more realistic replication of true environment in dynamic testing of structures. MIMO infers inputs from the desired responses at multiple locations on the test article of interest. Errors in the estimation of inputs include but are not limited to: output measurement errors and errors in the Transfer Function (TRF) matrix that captures the input-output relationship. A systematic study involving the measurement of acceleration, control system and system response were undertaken to investigate MIMO actuation of a fixed-end cantilever beam. The response of the beam was also modeled using closed-from equations and finite element method. Various actuation schemes were used to explore the effect of location of actuators in the context of the modal response of the beam. The MIMO input derivation was modeled using the Moore-Penrose Pseudo-Inverse of a rectangular Transfer Function matrix. The results of this study quantify the sources of uncertainty in MIMO vibration testing, specifically the errors due to equipment, sensor calibration, and actuator effects on the beam. The conclusions obtained from the cantilever beam used on this study can be extrapolated to more complex geometries.