Resumen de Design and control of flapping wing micro air vehicles
Flapping wing micro air vehicles (FWMAVs) have become an important research topic in recent years. Their potential applications, like search, rescue as well as surveillance and reconnaissance, make them attractive solutions with respect to traditional fixed or/and rotatory aerial vehicles. In this thesis, our research work focuses three main aspects of them: flapping transmission mechanism, flight attitude control and morphing-wing structure.
First, we propose a compliant transmission mechanism for a FWMAV, which was inspired by the thorax structures of insects. To better design the driving mechanism, kinematic analysis of the mechanism was derived. In addition, an aerodynamic model of wings was also built to be coupled with the flapping mechanism. Next, we proposed combining two methodologies, virtual-work-based and rigid-body dynamics-based approaches, to calculate and optimize the input torque required from the flapping actuator (DC motor). This allows designing a transmission mechanism that minimizes the sharp shock of the motor. After optimization, the compliant transmission mechanism with well-tuned parameters was shown to reduce the peak input torque up to 66\%, compared to a full rigid-body mechanism.
Second, we focus on the attitude control of the FWMAV. We proposed a type-2 fuzzy neural network working in parallel with a derivative differential controller to cope with system uncertainties and environmental disturbances. For the fuzzy neural network, two different triangular membership functions, with uncertain width and center, respectively, were used. With respect to these two cases, two new online learning algorithms were employed to update the parameters in both antecedents and consequents of the fuzzy neural network. After that, the stabilities of the two cases were proved by using both Lyapunov and sliding mode control theories. We applied the proposed methods to the attitude control model of the FWMAV. Simulation results demonstrate that the methods could effectively track the desired control signals even with system uncertainties and environmental disturbances.
Finally, we explore the effect of a morphing-wing structure inspired by bats. Bats have shown excellent flight characteristics in terms of high maneuverability and good stability by varying the geometry of their wings. A morphing-wing structure that mimics the mechanical system of bats' wings was integrated into the design of a flapping wing robot. To investigate the influence of changing the wing shape on the flight performance of the robot, in terms of lift and thrust forces, several experiments were performed. This approach provides an insight for developing future morphing-wing FWMAVs with the purpose of improving their maneuverabilities and flapping efficiency.
