Influence of Shaker Limitations on the Success of MIMO Environment Reconstruction

Several factors can prevent MIMO environment reconstruction tests from being successful, including the locations of the shakers and their directions, the set of accelerometers that are controlled to, and the upper and lower bounds of a shaker’s dynamic range. This work explores these issues for a simple component that flew on a sounding rocket in 2019, and which was instrumented with accelerometers to capture the operational environment in detail. Electrical models were estimated for three modal shakers to predict whether a certain configuration of shakers can recreate the environment without exceeding their input voltage capabilities. Tests are performed controlling to various sets of accelerometers. Finally, the condition number threshold and stinger length are investigated as potential solutions to insufficient shaker dynamic range. These factors are all studied by simulating a MIMO test using transfer functions measured in impact hammer testing, and physical MIMO testing is performed on the most promising test configurations using six modal shakers.