A micro-flight mechanism with rotational wings

A flight mechanism with 2 mm long micro-rotational wings has been designed and fabricated. The rotational wings are made of cobalt-nickel alloy and rotate in an alternating magnetic field. The flight mechanism is composed of the rotational wings, non-rotational body and disk. The wings and the disk are attached to glass rod and rotate together. As the rotating frequency increases, the wings and the disk move up and the disk pushes the body upwards, and then the whole structures take off. The characteristics of the rotational wings are investigated. A scale effect is found; the characteristics of the rotational wings get better as the wing length decreases. It is considered to be caused by the wing-longitudinal flow, which is often ignored in high Reynolds number flow. The non-rotational body has soft magnetic films. Due to the magnetic anisotropic torque exerted on the films, the body can maintain its attitude stability passively. The flight mechanism that weighs 1.6 mg succeeded in taking-off at 438 Hz keeping the attitude of the body stable. The magnetic torque between the external magnetic field and the wings must be larger than the torque from the air and the friction in order to keep the wings rotating. The relationship between the required magnetic field and the rotating frequency is investigated