Design of a parallel crank-rocker flapping mechanism for insect-inspired micro air vehicles

In the current paper, a novel micro air vehicle (MAV) flapping mechanism for replicating insect wing kinematics is presented. Insects flap their wings in a complex motion that enables them to generate several unsteady aerodynamic mechanisms, which are extremely beneficial for lift production. A flapping wing MAV that can reproduce these aerodynamic mechanisms in a controlled manner is likely to outperform alternative flight platforms such as rotary wing MAVs. A biomimetic design approach was undertaken to develop a novel flapping mechanism, the parallel crank-rocker (PCR). Unlike several existing flapping mechanisms (which are compared using an original classification method), the PCR mechanism has an integrated flapping and pitching output motion which is not constrained. This allows the wing angle of attack, a key kinematic parameter, to be adjusted and enables the MAV to enact manoeuvres and have flight stability. Testing of a near-MAV scale PCR prototype using a high-speed camera showed that the flapping angle and adjustable angle of attack both closely matched predicted values, proving the mechanism can replicate insect wing kinematics. A mean lift force of 3.35 g was measured with the prototype in a hovering orientation and flapping at 7.15 Hz.