Review on ultra-lightweight flapping-wing nano air vehicles: Artificial muscles,flight control mechanism,and biomimetic wings

Flying insects are capable of flapping their wings to provide the required power and control forces for flight. A coordinated organizational system including muscles, wings, and control architecture plays a significant role, which provides the sources of inspiration for designing flapping-wing vehicles. In recent years, due to the development of micro- and meso-scale manufacturing technologies, advances in components technologies have directly led to a progress of smaller Flapping-Wing Nano Air Vehicles (FWNAVs) around gram and sub-gram scales, and these air vehicles have gradually acquired insect-like locomotive strategies and capabilities. This paper will present a selective review of components technologies for ultra-lightweight flapping-wing nano air vehicles under 3 g, which covers the novel propulsion methods such as artificial muscles, flight control mechanisms, and the design paradigms of the insect-inspired wings, with a special focus on the development of the driving technologies based on artificial muscles and the progress of the biomimetic wings. The challenges involved in constructing such small flapping-wing air vehicles and recommendations for several possible future directions in terms of component technology enhancements and overall vehicle performance are also discussed in this paper. This review will provide the essential guidelines and the insights for designing a flapping-wing nano air vehicle with higher performance.