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Abstract: Negative-imaginary systems have important engineering applications, for example, in lightly damped flexible structures with collocated position sensors and force actuators. This paper proposes a new Negative-Imaginary Lemma for generalized negative-imaginary systems, where the minimality assumption is relaxed. The proposed lemma facilitates both analysis and synthesis for negative-imaginary systems. Invoking this result, a systematic robust static state-feedback synthesis method is proposed in an LMI framework for systems with strictly negative-imaginary uncertainty (e.g. unmodeled spill-over dynamics in a lightly damped flexible structure) assuming all states are available for state feedback. Two numerical examples are given to show the usefulness of the proposed results. [Copyright &y& Elsevier]

Abstract: Varying ambient light may cause serious decorrelation effect in the images recorded using an ordinary optical imaging device, which prevent digital image correlation (DIC) from out-of-laboratory use. In this paper, we describe an easy-to-implement yet effective monochromatic light illuminated active imaging DIC method for obtaining high-quality images suitable for high fidelity deformation measurement. Experiments reveal that the active imaging DIC method is able to provide reliable and accurate measurements even though the ambient light has been seriously changed. The active imaging DIC method is promising for developing flexible and robust in situ deformation measurement systems for use in both laboratory and non-laboratory environment, and should therefore have more potential engineering applications. [Copyright &y& Elsevier]