There exist multiple types of flyers in the world that either achieve lift through leveraging aerodynamics by cleverly choosing the wing airfoils of an airplane, or by flapping their wings. As the flapping wing vehicles (FWVs) decrease in scale, lift is predominantly generated by flapping. However, bigger birds or bird-scale flapping wing vehicle (BFWV) may not be able to hover but leverage the forward velocity to augment the lift generation. In this paper, we analyze the aerodynamic lift augmentation through the translational velocity for a 12g, BFWV with tail (flapping around 14 Hz). We prove that the vehicle is unable to hover, but there exist a significant augmentation through the translational motion. A cycle-averaged aerodynamic model including the contribution from the translational velocity is proposed, and experimentally validated. Finally, the analysis of the sufficient conditions on the velocity direction and orientation are studied to maintain the zero angular moment forward flight.

Mantis shrimp produce one of the fastest strikes in the animal kingdom, their striking appendages reaching tip velocities of tens of meters per second underwater. Their ultrafast movement is capable of crushing the shells of prey and generating cavitation bubbles, and has long raised interest from the scientific community. To study the underlying mechanisms and operating principles behind these behaviors, prior research has developed physical models that mimic the motions and speeds of mantis shrimp. That microrobot demonstrated speeds of approximately 5 m/s in water and 26 m/s in air. Here we utilize an accurate dynamical model of the four-bar mechanism and geometric latch observed in biological shrimp in a numerical trajectory optimization approach to find the design changes that can maximize the microrobot's striking velocities. Through a suboptimization problem maximizing the energy loaded in the mechanism's spring, we manage to improve the performance of the microrobot by over 58%, reaching tip velocities of$41.2 \pm 0.6$m/s.

Flapping-wing micro-aerial vehicles rely on subtle changes in the kinematics of high-frequency wing flapping to produce roll, pitch, and yaw torques. To generate yaw torque, the Harvard RoboBee changes the ratio of upstroke to downstroke speed (“split-cycling”) by applying a second harmonic to the fundamental flapping signal for each wing. However, since flapping typically occurs near resonance (for efficiency), these higher harmonics are filtered out by the transmission and actuator dynamics. Therefore, reliable yaw control authority has proven elusive. We propose a method to generate yaw torque sufficient for in-flight control by using split-cycle flapping in an “iso-lift” regime, to mitigate resonant filtering by decreasing the flapping frequency and increasing the drive voltage, which produces lift identical to typical flight conditions. We model the expected torque at iso-lift conditions and apply this method to the physical RoboBee, achieving reliable, controllable yaw torque. Finally, we demonstrate yaw control with a simple heading controller, achieving a step response with a time constant an order of magnitude faster than previous attempts.