In this study, an active vibration suppression control is presented for use in a two degree-of-freedom piezoelectric flexible structure system containing a rectangular plate driven by dc motors. A mathematical model involving a clamped-free-free-free cantilever flexible plate, piezoelectric transducer, and motor dynamics is derived for modal analysis and control design. To simplify the control design of this multivariable system, a two-stage design strategy is proposed because the plate motion exerts a comparatively small effect on the dc motors. Both the plate vibration and coupling effect in the motors are considered when designing a centralized motor tracking controller. Given a well-designed two-axis motor control system, piezoelectric actuators are used on the plate to perform efficient active vibration suppression control. Hybrid proportional-derivative and repetitive control methods are extended to manage the multiple-period disturbances and resonant excitation. Three sets of simulation experiments were conducted, focusing on suppressing the plate vibration response and demonstrating the effectiveness of the proposed method.
Optical trapping at interfaces has recently gained relevance due to the expansion of optical potential far away from the focus, especially for proteins where submillimeter structures have been described. Initially, lysozyme clusters are trapped as a shallow layer at the surface, becoming thicker with the irradiation time. Nonetheless, overcoming a concentration threshold, lysozyme clusters inside solution are collected and transported toward the focus, invading the lysozyme layer, which results to a border between them, although no concentration jump is detected. This two-stage optical trapping occurs due to long-range interaction originating from the focus.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.