UWB localization for autonomous indoor position control of VTOL UAVs

Abstract

As the popularity of quadrotor Vertical Take-Off and Landing (VTOL) Unmanned Aerial Vehicles (UAVs) grows, the need for reliable position estimation and control grows as well. Furthermore, with the size of these quadrotors decreasing and indoor use becoming possible, the need for indoor position estimation methods where Global Position System (GPS) measurements are unavailabe, is a growing topic to which many solutions have been suggested. Herein a method fusing Ultra-Wideband (UWB) range measurements and Inertial Measurement Unit (IMU) measurements is implemented to produce reliable position and velocity estimates. The position and velocity estimates from this system are then used as inputs to a position controller for the VTOL UAV system. Due to the underactuated nature of the system the position cannot be directly controlled, as such an intermediary control signal is defined. This intermediary control is used to determine the desired orientation and thrust of the UAV, which can then be controlled to achieve the desired position control. As the true orientation of the UAV is not directly measurable an observer using the available IMU measurements is utilized to estimate the orientation of the UAV. Simulation and implementation results for the position estimation system, as well as the position control system are given.