New Wing Stroke and Wing Pitch Approaches for Milligram-scale Aerial Devices
This work addresses design complexity in micro-aerial vehicles, offering incremental improvements to existing flexure-based methods for researchers and engineers in robotics and aerodynamics.
The paper tackles the challenge of designing transmission and wing pitch mechanisms for milligram-scale aerial devices by introducing a simple, planar, compliant transmission that converts linear motion to rotary wing stroke and a passive wing pitch mechanism that decouples design parameters. The transmission requires no assembly and works with any linear actuator, while the pitch mechanism allows post-fabrication tuning of wing pitch amplitude.
Here we report the construction of the simplest transmission mechanism ever designed capable of converting linear motions of any actuator to $\pm$60$^\circ$ rotary wing stroke motion. It is planar, compliant, can be fabricated in a single step and requires no assembly. Further, its design is universal in nature, that is, it can be used with any linear actuator capable of delivering sufficient power, irrespective of the magnitude of actuator displacements. We also report a novel passive wing pitch mechanism whose motion has little dependence on the aerodynamic loading on the wing. This exponentially simplifies the job of the designer by decoupling the as of yet highly coupled wing morphology, wing kinematics and flexure stiffness parameters. Like the contemporary flexure-based methods it is an add-on to a given wing stroke mechanism. Moreover, the intended wing pitch amplitude could easily be changed post-fabrication by tuning the resonance mass in the mechanism.