Fuzzy programming approach to UAV preliminary sizing

In preliminary sizing, wing loading, power loading, and maximum lift coefficient are commonly determined through an informal optimization process using statistical equations based on existing aircraft data in conjunction with a matching chart from which the best design point is picked. Presented here is an alternative method where these pivotal design parameters are computed using non-statistical flight dynamics equations immersed within a fuzzy multi-objective non-linear programming framework. A fixed-wing surveillance unmanned aerial vehicle (UAV) for disaster risk reduction and climate change adaptation is designed to illustrate the method. The mission specification of the UAV sets the constraints on six chosen performance parameters. Two types of membership function - ramp and triangular - that capture the tolerability of constraint violation are studied. Derived from the results are the wing area and power necessary for the UAV to satisfy the performance requirements and fulfill its mission. Together with the maximum lift coefficient, these parameters are critical inputs of the next phase of the design process which is configuration design.