Micro Aerial Vehicles (MAVs) are a class of Unmanned Aerial Vehicles (UAVs) designed for closed-quarter and small/tight space navigational operations. The conventional Micro Aerial Vehicle (MAV) as outlined by the Defense Advanced Research Projects Agency (DARPA), is a vehicle that can have a maximum dimension of 6 inches and weighs no more than 100 grams. Under these tight constraints, the footprint, weight and power reserves available for on-board avionics and actuators is drastically reduced; the flight time and payload capabilities of MAVs take a massive toll in keeping up with these stringent size constraints. However, the demand for micro flying robots is increasing rapidly.;The applications that have emerged over the years for MAVs include search & rescue operations, remote Intelligence, Surveillance and Reconnaissance (ISR), among many others. However, the biggest setback in urban operations and closed quarter navigation is enabling hover-capability / Vertical-Take-Off-and-Landing (VTOL) along with long flight times, high sensor/telemetry payload capacity and small size. VTOL capable rotary and fixed wing flying vehicles do not scale down to micro sized levels, owing to the severe loss in aerodynamic efficiency associated with low Reynolds number physics on conventional airfoils. Some of the biologically inspired designs developed so far include the MicroBat, by Caltech, Mentor, by University of Toronto and Delfly by the Technical University of Delft and Wageningen University and lately the Hummingbird by Aerovironment. However, the present state of the art lacks in one or more of the minimum qualities required from an MAV: Appreciable flight time, payload capacity and Six Degrees of Freedom (6DoF) hovering/VTOL performance. This PhD. work is directed towards overcoming these limitations.;Firstly, this PhD thesis presents the advent of a novel Quad-Wing MAV configuration (termed, QV) capable of performing all 6DoF flight maneuvers. The thesis presents the theory, conceptualization, design, simulation study and finally hardware design/development of the MAV.;Secondly, it proves and demonstrates a significant improvement in on-board energy-harvesting, capable of resulting in increased flight times and payload capacities of the order of even 200%-400% and more.;Thirdly, the thesis defines a new actuation principle, called Fixed Frequency, Variable Amplitude (FiFVA). It is demonstrated that by the use of passive elastic members on wing joints, a further noteworthy increase in energy efficiency, and consequently reduction in input power requirements is observed. An actuation efficiency increase of over 100% in many cases is predicted. The natural evolution of the actuation development led to invention of two novel actuation mechanisms that are intended to illustrate the FiFVA actuation principle, and consequently show energy savings and flapping efficiency improvement.;Finally, the thesis presents supplementary work in the design, development of two novel Micro Architecture and Control (MARC) avionics platforms (autopilots) to demonstrate flight control and communication capability on-board the four-wing flapping prototype. The design of a novel passive feathering mechanism aimed to improve lift/thrust performance of flapping motion is also presented.;The contributions emerging from the research are:;1. A novel Quad-Wing MAV configuration (termed, QV) for generating a very notable increase in flight time and payload capacity.;2. A novel 6DoF flight control law for the Quad-Wing MAV design.;3. A novel resonance flapping principle termed FiFVA, for significantly improving flapping efficiency using passive elastic elements on wing joints (springs).;4. Two novel FiFVA operated mechanical actuation prototypes and a fully functional Quad-Wing MAV prototype with two indigenously developed Micro Architecture and Control (MARC) avionics platforms.
展开▼
