Examination Committee

Prof Michael WANG, ECE/HKUST (Chairperson)
Prof Zexiang LI, ECE/HKUST (Thesis Supervisor)
Prof Fu ZHANG, ECE/HKUST (Thesis Co-supervisor)
Prof Shaojie SHEN, ECE/HKUST

Abstract

In recent years, there has been an increasing interest within the robotics community in developing vertical take-off and landing (VTOL) unmanned aerial vehicles (UAV). A VTOL UAV combines the desirable capabilities of rotary-wing and fixed-wing aircraft in a single platform, enabling the vehicle to vertically take off and land and perform highly efficient level flight. Such capacities provide unique opportunities that are generally not possible for conventional fixed-wing airplanes or rotary-wing aircrafts. For example, a meaningful surveillance task requires a significant level of flight endurance and range that are usually beyond the capacity of current multirotor platforms, an efficient UAV platform such as VTOL vehicles becomes particularly useful in these application scenarios.

This thesis presents the design and control of a tail-sitter VTOL (Vertical Take-off and Landing) UAV, which is composed of a quadrotor for attitude control and a pair of wings for efficient level flight. To enhance the stability and maneuverability of designed UAV, the aerodynamic and mechanical designs are optimized. Both of them play a very important role in power efficiency and flight stability. Different from the traditional quadrotor and the fixed-wing airplanes, a new hierarchical control system is designed to achieve high accuracy in the attitude control with four rotors and the stable level flight. The prototype is built and test, and able to transit between hovering mode and level flight stably and reliably. Results of the flight tests are provided to show the performance of the designed VTOL, and its superior power consumption over a conventional quadrotor.