Fused deposition modelling (FDM) to fabricate a transitional vertical take-off and landing (VTOL) unmanned aerial vehicle (UAV) for transportation of medical supplies in underdeveloped areas.

Abstract

This dissertation’s work has focused on the design and development of a prototype UAV that aims to facilitate the delivery of emergency medical aid supplies to remote locations within South Africa (SA). This research has conducted a conceptualized design of a tilt-rotor VTOL UAV named Airslipper, which was entirely fabricated using FDM methods. Identification of key performance parameters within the vehicle’s mechatronic design enabled this research to conduct a simultaneous optimization on the propeller-based propulsion system and aerodynamic configuration. Execution of MATLAB’s ‘gamultiobj’ function on two parametrically formulated objective functions resulted in a UAV setup that increased flight endurance by 𝟓8 𝒔𝒔. This improvement amplified the effectiveness of this system and expanded the service radius distance by 𝟏.𝟓1 𝒌m. The outcome of a stability and sensitivity analysis performed on the Airslipper’s aerodynamic surfaces provided critical information that contributed towards the vehicle’s flight characteristics. Findings indicated a stabilized design that exhibited appropriate frequency plots for both longitudinal and lateral stability modes. The addition of a plane analysis, which included viscous and inertial effects, offered essential drag and pressure coefficients, which aided in the final design. This research correspondingly conducted several CFD simulations on an Airslipper model, which allowed this work to examine further the fluid behaviour characteristics endured on the vehicle in both VTOL and Fixed Wing (FW) modes. Simulation findings revealed standard pressure distributions, which confirmed thrust and lift forces for the relevant components without performance compromise. This research proposed to experimentally investigate a correction factor for an FDM fabricated aerofoil that aimed to determine what structural effects were apparent for a printed part with varying FDM parameters. Outcomes demonstrated greater resilience to failure for parts that had reduced layer heights and increased infill percentages. Fabrication of the Airslipper comprised of 99 individually printed parts that encompassed a specific parameter combination which pertained to the design’s importance. Validating the prototype’s functionality was achieved through a series of hover tests that generated suitable data logs plots for the control response, actuator output signals, vibration metrics, and power. This research concluded by discussing the Airslipper’s design and fabrication method with further mentioning of recommendations for potential improvements.