Development of an Insect-like Flapping-Wing Micro Air Vehicle with Parallel Control Mechanism

Most traditional flapping-wing micro air vehicles (FMAVs) adopt a serial control mechanism, which means that one drive corresponds to one degree of freedom. However, the serial mechanism often struggles to meet FMAV requirements in terms of stiffness, size, and reliability. In order to realize a compact reliable control mechanism, we developed a two-wing insect-like FMAV with a parallel control mechanism. The prototype possesses an optimized string-based flapping wing mechanism, a 2RSS/U parallel control mechanism, and an onboard power supply and controller. The pulley's profile of the string-based mechanism was refined to reduce the deformation and impact of the string. The parameters of the parallel mechanism were designed to enable the stroke plane to rotate a large angle to produce control torque. The prototype had a flapping frequency of 25 Hz, a full wingspan of 21 cm, and a total weight of 28 g. A PID controller with a decoupler based on the kinetics solution of parallel mechanism was designed to control the FMAV. A force and torque (F/T) experiment was carried out to obtain the lift and control torque of the prototype. The measured data showed that the flapping wing mechanism provided sufficient lift and the control mechanism generated a toque caused by the stroke plane rotation and trailing edge movement and were linear to the control input. A flight test was carried out to verify the flight stability of the prototype. The result shows that the attitude angle only fluctuates within a small range, which proved that the control mechanism and control strategy were successful.