Nonlinear Semi-active Damping using Constant or Adaptive Voltage Sources: A Stability Analysis

Semi-active vibration control techniques by nonlinear treatment have experienced strong development these last years, due to their effectiveness and advantages compared to passive and active approaches. In particular, the Synchronized Switch Damping (SSD) technique leads to very effective attenuation. This technique consists of a nonlinear processing of the piezovoltage that induces great enlargement of the electromechanical energy conversion. The SSD technique can be improved by switching on continuous voltage sources (SSDV), leading to an enlargement of the conversion energy cycle. This method is almost as effective as active techniques, but might generate instabilities. This article deals with these particular problems, focusing on CICO stability (Converging Input, Converging Output) and robustness. The study considers a theoretical and a technological point of view, confirmed by experimental results. The article also considers an enhanced SSDV, which uses matched continuous voltage sources, whereas the classical SSDV uses constant voltage sources. Simple monomodal and multimodal models of an electromechanical vibrating structure are proposed. Stability and robustness are discussed for the classical and enhanced SSDV techniques using the first harmonic method. It is shown both theoretically and experimentally that the enhanced SSDV is much more stable than the classical SSDV.