Birds are agile in locomotion and able to move quickly and easily from one place to another. When a bird is on the ground, and a threat approaches, the bird will fly away and escape. An ornithopter robot provides advantages in energy saving, maneuverability, and crash safety. Most flapping robots require an operator or assistance to take off. The goal of this study is to enable self-takeoff from the ground. The developed robot can generate thrust to its body by exceeding its own weight using a simple flapping mechanism and lightweight design. The result of the takeoff experiment showed that the ornithopter robot was able to self-takeoff from the ground without assistance.

This paper presents small signal ac analysis of LLC current resonant converter. Equivalent source model that represents a switching element as an equivalent source having averaged current and voltage is employed and described in detail. From analysis, the transfer function of the switching frequency to the output voltage of the converter becomes a quadratic system. Resonant capacitor and inductor do not affect directly to the small signal characteristics. However they affect a dc gain and an internal resistance. The analysis method is confirmed by experiments, and experimental results are relatively consistent with the analytical results.

Vehicles employing idle reduction system need a step up DC-DC converter which operates stably for a voltage drop of a battery during engine restart. This paper proposes a power supply for idle reduction system employing a ripple regulator having an excellent transient performance and stability without using electrolytic capacitors which results in long life. The feedforward circuit is employed in order to improve transient response for large input voltage change. The prototype converters were experimentally examined to verify the transient performance for the large variations of the load current and input voltage.