Recent Progress Towards Developing an Insect-Inspired Flapping-Wing Micro Air Vehicle

This paper presents an overview of the on-going research activities at Shrivenham, aimed at the design of an autonomous flapping-wing micro air vehicle. After introducing the problem of insect wing kinematics and aerodynamics, we describe our quasi-three-dimensional aerodynamic model for flapping wings. This is followed by a brief discussion of some aerodynamic issues relating to the lift-generating leading-edge vortex. New results are then presented on modelling of wing aeroelastic deflections. Finally, some brief observations are made on flight control requirements for an insect-inspired flapping-wing micro air vehicle. Overall, it is shown that successful development of such a vehicle will require a multi-disciplinary approach, with significant developments in a number of disciplines. Progress to date has largely been concerned with hover. Little is known about the requirements for successful manoeuvre. 1.0 INTRODUCTION Agile flight inside buildings, caves and tunnels is of significant military and civilian value. Current surveillance assets (e.g. satellites, UAVs) possess virtually no capabilities of information-gathering inside buildings. The focus on indoor flight leads to the requirement of a distinct flight envelope. In addition, autonomy is required to enable mission-completion without the assistance of a human telepilot; this requires precise flight control. Current unmanned aerial vehicles (UAVs) are too large to achieve indoor flight and our research has concluded (see Refs [1][2][3]) that insect-like flapping flight is the optimum way to fulfil this capability — fixed wing aircraft do not have the required low-speed agility and miniature helicopters are too inefficient and noisy. Insect flapping flight, on the other hand, has been present in nature for over 300 million years [4] and has been perfected over this time. Insects fly at low speeds, are extremely manoeuvrable, virtually silent and most are capable of hover. In addition, insect flapping flight also offers significantly better power efficiency, particularly at low flight speeds, than both fixed-wing aircraft and rotorcraft [5][6], making it ideal for our focus on micro UAVs for indoor flight. Cranfield University at Shrivenham, together with our partners in other universities (currently Oxford, Heriot-Watt and Bristol) are engaged in world-leading research on flapping-wing micro air vehicles (FMAVs), based on insect-like aerodynamics. A micro air vehicle is defined here as a hand-sized flying machine having no dimensions greater than ca. 15cm. This paper will review our key work to date. The paper is organised as follows. First, the flapping-wing problem is introduced by familiarising the reader with insect flight kinematics and relevant aerodynamic phenomena. Then, a brief description of our aerodynamic model is presented. This is followed by discussion of some relevant aerodynamic phenomena which are not directly captured in this model. We next discuss some recent findings on aeroelasticity before finally highlighting some considerations for flight control of an FMAV. RTO-MP-AVT-146 35 1 UNCLASSIFIED/UNLIMITED UNCLASSIFIED/UNLIMITED Knowles, K.; Ansari, S.A.; Wilkins, P.C.; Zbikowski, R.W. (2007) Recent Progress Towards Developing an Insect-Inspired Flapping-Wing Micro Air Vehicle. In Platform Innovations and System Integration for Unmanned Air, Land and Sea Vehicles (AVT-SCI Joint Symposium) (pp. 35-1 – 35-12). Meeting Proceedings RTO-MP-AVT-146, Paper 35. Neuilly-sur-Seine, France: RTO. Available from: http://www.rto.nato.int/abstracts.asp. Report Documentation Page Form Approved OMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE 01 NOV 2007 2. REPORT TYPE N/A 3. DATES COVERED 4. TITLE AND SUBTITLE Recent Progress Towards Developing an Insect-Inspired Flapping-Wing Micro Air Vehicle 5a. CONTRACT NUMBER