Browsing by Author "Lal Kummari, K."

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    Coupled piezoelectric fans with two degree of freedom motion for the application of flapping wing micro aerial vehicles
    (Elsevier Science B.V., Amsterdam., 2008-10-03T00:00:00Z) Chung, H. C.; Lal Kummari, K.; Croucher, S. J.; Lawson, Nicholas J.; Guo, Shijun J.; Huang, Zhaorong
    Piezoelectric fans consisting of a piezoelectric layer and an elastic metal layer were prepared by epoxy bonding and a coupled flexible wing was formed by a pair of carbon fibre reinforced plastic wing spars and polymer skin attached to two piezoelectric fans. Two sinusoidal voltages with phase differences were then used to drive the coupled piezoelectric fans. High speed digital cameras were used to characterize the two degree of freedom (DOF) motion of the wing and these results were compared to finite element model of the wing and the coupled piezoelectric fans. It has been observed that the phase delay between the driving voltages applied to the coupled piezoelectric fans plays an important role in the control of the flapping and twisting motions of the wing and this set-up has the potential for application to the control of flapping wings for micro aerial vehicles. (c) 2008 Elsevier B.V. All rights reserved.
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    Development of piezoelectric actuated mechanism for flapping wing micro-aerial vehicle applications
    (Maney Publishing, 2010-03-31T00:00:00Z) Lal Kummari, K.; Li, Daochun; Guo, Shijun J.; Huang, Zhaorong
    A piezoelectric actuated two-bar two-flexure motion amplification mechanism for flapping wing micro-aerial vehicle application has been investigated. f(r)*A as an optimisation criterion has been introduced where f(r) is its fundamental resonant frequency of the system and A the vibration amplitude at the wing tip, or the free tip deflection at quasi-static operation. This criterion can be used to obtain the best piezoelectric actuation mechanism with the best energy transmission coefficient for flapping wing micro-aerial vehicle applications, and is a measurable quantity therefore can be compared with experimental results. A simplified beam model has been developed to calculate the fundamental resonant frequency for the full system consisted of piezoelectric actuator, motion amplification mechanism and the attached wing and the calculated values were compared with the measured results. A clear trend of the criteria f(r)*A varying with the two-flexure dimension, stiffness and setting angle have been obtained from the measured data and also the predicted results as a guideline for optimal design of the system.