Micro aerial vehicle flapping actuation: an experimental analysis of crank and sliding lever mechanisms

Artificial flapping-wing robots necessitate a lightweight transmission mechanism with minimal interconnected parts, posing challenges to their development. This paper explores the design and analysis of a flapping actuation mechanism utilizing a crank and sliding lever configuration to convert rotational motion into angular flapping. The proposed mechanism represents a minimalist design concept with lightweight components specifically tailored for mosquito-sized flapping wing applications, contrasting with traditional, heavier four-bar mechanisms. Flight control is achieved through the crank slider design, facilitating essential maneuverability. Moreover, variations in forward and return stroke velocities contribute to enhanced lift generation. Structural and kinematic analysis of the flapping actuation mechanism are conducted to determine parameters such as wing angular velocity, acceleration, flapping angle, and frequency under maximum input voltage. Experimental validation of the concept is performed using data from a designed prototype, or flapping-wing testbed. Flapping angle measurements, similar to those of a mosquito, are verified using an ultrasonic sensor. Frequency validation involves separate flapping measurements on the testbench model using an infrared sensor and a laser tachometer, with validation of forward and reverse stroke durations. The return stroke consumed 37 percent of the cycle period, making it significantly faster than the forward stroke, which takes up 63 percent. Consequently, the time ratio between the forward and return strokes is 2:1, generating a favorable lift force throughout the wing's flapping cycle. This validates the sliding lever movement concept, with variations in the time and speed of flapping for both strokes observed in analytical results, simulation outcomes, and real-time testing.The suitability of the sliding lever mechanism for Micro Aerial Vehicle(MAV) flapping-wing applications is confirmed through these analysis and experiments.