RESUMO
In this paper, we propose a platform for an insect-like flapping winged micro aerial vehicle with a resonant wing-driving system using extension springs (FMAVRES). The resonant wing-driving system is constructed using an extension spring instead of the conventional helical or torsion spring. The extension spring can be mounted more easily, compared with a torsion spring. Furthermore, the proposed resonant driving system has better endurance compared with systems with torsion springs. Using a prototype FMAVRES, it was found that torques generated for roll, pitch, and yaw control are linear to control input signals. Considering transient responses, each torque response as an actuator is modelled as a simple first-order system. Roll, pitch, and yaw control commands affect each other. They should be compensated in a closed loop controller design. Total weight of the prototype FMAVRES is 17.92 g while the lift force of it is 21.3 gf with 80% throttle input. Thus, it is expected that the new platform of FMAVRES could be used effectively to develop simple and robust flapping MAVs.
RESUMO
The electrohydrodynamic (EHD) spraying technique has been utilized in applications such as inkjet printing and mass spectrometry technologies. In this paper, the role of electrical potential signals in jetting and on the oscillation of the meniscus is evaluated. The jetting and the meniscus oscillation behavior are experimentally investigated under ac voltage, ac voltage superimposed on dc voltage, and pulsed dc voltage. Based on this in-depth study of the meniscus behavior under various signals, the optimal signal is implemented to an EHD inkjet head for drop-on-demand operation. For applied ac voltage and ac voltage superimposed on dc voltage, the jetting phenomenon is a dynamic process due to sequential opposite sign signals. The jetting occurs at the end of the oscillation cycle, where the meniscus oscillates upward and arrives at its highest position.
