Reconfigurable Quadrotors with Energetically Efficient Multimodal Locomotion

Project: Research

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With foreseeable applications such as reconnaissance and transportation, research in small, human-friendly micro aerial vehicles has received tremendous attention from scientists and engineers. These small robots have the potential to revolutionize our use of robots for civilian applications. Compared to conventional aircraft, however, at centimeter scales, flying robots suffer from a radical reduction in aerodynamic efficiency. The elevated energetic cost of staying airborne severely limits the flight endurance and range. Not only to overcome the energetic restriction but also to broaden the functionalities, research in multimodal locomotion of aerial robots has gained interests. For small vehicles, surface locomotion becomes favorable due to the increased surface-to- weight ratio. With suitable adhesion, small robots are able to perch on overhangs in urban areas to conserve energy. Hybrid terrestrial locomotion has been demonstrated as a viable strategy for traversing through unstructured environments. Nevertheless, to date, multimodal locomotion often comes with a tradeoff as it necessitates extra actuators or sophisticated mechanisms to accommodate the conflicting requirements of different locomotion modes. In this proposed research, we will show how simple aerodynamic effects and folding mechanisms can be leveraged to create a novel transformable quadrotor with prolonged endurance and range through surface and terrestrial locomotion. This research will address the issues of energetic efficiency of small aerial robots in three steps. First, to achieve surface locomotion, we employ the ceiling effects. Based on our preliminary experiments, when a spinning propeller is placed below a horizontal surface, we observe a threefold decrease in power consumption. We seek to model and leverage the ceiling effects for the robot to perch and stay elevated while consuming significantly less energy. Second, we aim to combine these aerodynamic effects with microspines and design a mechanism that permits the robot to passively perch on a wall without feedback. The use of proximity effects enhances the thrust-assisted perching envelope as it contributes to a significant increase in the surface attraction. Finally, we adopt an origami-inspired, planar fabrication paradigm to fabricate a strong and lightweight transformable airframe. This passive foldable structure enables the robot to rotate the thrust vectors for rolling on flat terrain. Compared to the existing design, the reorientation of thrusts lowers the power dissipation by up to a factor of two, resulting in a radically extended range for the terrestrial locomotion. It is perceivable that the proposed research will contribute to advances in the field of micro aerial vehicles by expanding their endurance and operational range, broadening the applications of aerial robots. Scientific merits will come from (i) the development of aerodynamic models and validation of the ceiling effects of spinning propellers; (ii) the implementation of mechanically intelligent designs for passive transformation that provides additional functionalities; and (iii) the realization of an energetically efficient robot with an aerial-surface-terrestrial locomotion. 


Project number9042782
Grant typeGRF
Effective start/end date1/01/20 → …