This article proposes a new hybrid active mount featuring piezostacks and rubber element that can provide high performance in vibration control. After describing the configuration and operating principle of the proposed mount, appropriate rubber element and piezostack are designed and manufactured. Subsequently, dynamic characteristics of the piezostacks and the rubber element are experimentally identified. A two-degree-of-freedom control system, in which the hybrid active mount is installed with a supported mass of 100 kg, is then constructed for evaluating vibration control performance. To attenuate actively the vibration transmitted from the base excitation, a robust sliding mode controller is formulated by considering parameter uncertainties. The controller is then experimentally realized and vibration control performances of the proposed mount system are evaluated in both time and frequency domains.
The present work performs numerical optimization for design of blade stacking line for an axial flow fan with response surface method using three-dimensional Navier -Stokes analysis, and evaluates the effects of sweep and lean on the performance of the fan blade. Reynolds-averaged Navier -Stokes equations are discretized with finite-volume approximations using unstructured grids. Four geometric variables concerning spanwise distributions of sweep and lean of blade stacking line are chosen as design variables to find maximum efficiency. The computational results show good agreements with experimental data. The total efficiency is successfully increased in comparison with the reference fan by optimizing threedimensional stacking line with sweep and lean. Coupling of sweep and lean also improves off-design performance of the blade remarkably.
In this work, a new active mount featuring piezostack actuators and a rubber element is proposed, and its vibration control performance is evaluated by implementing an adaptive controller. The proposed mount is designed for particular applications that require high-performance isolation against broadband excitation, such as vibration-sensitive shipboard equipment. After describing the configuration of the proposed mount, the design and manufacture of the rubber element and piezostack actuators are described. A vibration control system is then constructed, in which the proposed mount is loaded with a lumped mass subjected to base excitations. To attenuate vibrations on the supported mass, an adaptive frequency-shaped sliding mode controller is formulated based on the Lyapunov's theorem. In the presence of inexactly known parameters, the proposed controller tends to drive the system to a desired dynamic while the system parameters are updated by adaptive laws. Finally, the controller is experimentally realized, and vibration control performances are evaluated in time and frequency domains.
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