Design and stable flight of a 21 g insect-like tailless flapping wing micro air vehicle with angular rates feedback control

Feedback Control-Based Navigation of a Flying Insect-Machine Hybrid Robot

This study reports the first ever demonstration of the aero navigation of a free-flying insect based on feedback control. Instead of imitating the complicated kinetics and mechanisms of insect locomotion, a live insect can be directly transformed into a soft robot by embedding it with artificial devices. Since many insects can perform acrobatics aerially, thereby exhibiting far greater flexibility than current man-made flyers, correctly commanding the internal structures of an insect to perform based on the instructions would be a breakthrough. Herein, beetles (Mecynorrhina torquata) were chosen as the flying platform, and an inertial measurement unit-implemented electronic backpack was designed and manufactured to remotely command the beetles. To achieve horizontal flight control, multiple flight muscles of the beetles, that is, the basalar and third axillary muscles were stimulated to control the flight directions. However, the beetles were found to gradually adapt to the electrical stimulation, and the flight corrections were elicited by generating compensatory flight forces during a long-lasting stimulation (>300 ms), which were revealed by the decrease in induced lateral force. Based on this finding, a proportional derivative feedback controller was designed to navigate the flying beetles based on the predetermined path using frequency-dependent electrical pulses. To avoid a continuous stimulation, we proposed a stimulation protocol which separated two stimulations with a 50-ms rest. Compared to long stimulations (>300 ms), a 150-ms stimulation with 200-ms update interval was more efficient in correcting the flight direction of the beetles.

Experimental Investigation of Aerodynamics of Feather-Covered Flapping Wing

Avian flight has an outstanding performance than the manmade flapping wing MAVs. Considering that the feather is light and strong, a new type of the flapping wing was designed and made, whose skeleton is carbon fiber rods and covered by goose feathers as the skin. Its aerodynamics is tested by experiments and can be compared with conventional artificial flapping wings made of carbon fiber rods as the skeleton and polyester membrane as the skin. The results showed that the feathered wing could generate more lift than the membrane wing in the same flapping kinematics because the feathered wing can have slots between feathers in an upstroke process, which can mainly reduce the negative lift. At the same time, the power consumption also decreased significantly, due to the decrease in the fluctuating range of the periodic lift curve, which reduced the offset consumption of lift. At the same time, the thrusts generated by the feather wing and the membrane wing are similar with each other, which increases with the increase of flapping frequency. In general, the aerodynamic performances of the feather wing are superior to that of the membrane wings.