Analyses of drives power reduction techniques for multi-axis random vibration control tests

In multi-axis vibration control testing, the power required by the excitation system for replicating the user defined test specifications is a limiting factor which cannot be overlooked. Excessive power, on top of over-stressing the often expensive test equipment, could cause data acquisition overloads which inevitably interrupt the test even before the full level run. An accurate definition of the Multi-Input Multi-Output (MIMO) control target allows to perform the control test minimising the overall power required by the shakers. In this sense, in the recent years advanced procedures have been developed in this research direction. This paper analyses the available drives power reduction techniques, offering a detailed overview of the current state-of-the-art. Furthermore, this paper provides a novel solution to manage the cases where most of the power is required by a single drive of the multiple inputs excitation system. In order to point out the pros and cons of each procedure and to show the capabilities of the novel technique, the MIMO target generation algorithms are firstly theoretically explained and then experimentally compared by using a three-axial electrodynamic shaker.