Rotational Energy Harvesting to Prolong Flight Duration of Quadcopters

Abstract

This thesis presents a rotational energy harvester using brushless direct current (BLDC) generator to harvest ambient energy for quadcopter in order to prolong it flight duration. Quadcopters also known as drones are developed with the intention of operating in conditions where the presence of an on-board human pilot is either too risky or unnecessary, as such they are broadly referred to as UAV (Unmanned Aerial Vehicles). For a drone its endurance is essential in order to achieve operational goals, because most electrically powered drones have a limitation on size and mass, due to this they cannot carry a large mass of on-board energy thereby having short flight time. Quadcopters have a lot benefits such as large amount of controllability, hovering and manoeuvrability, because of this they are suitable for both indoor and outdoor applications such as scientific research, security surveillance and reconnaissance. BLDC generators are coupled with the propellers of the quadcopter to transfer kinetic= energy from the propellers to the generator. Taking into consideration the power requirement of quadcopter, the output of the generator is amplified using DC-DC boost and regulated to power and charge the on-board battery. The BLDC generator was simulated in MATLAB/SIMULINK, monitor and analyse the output of the generator. A final prototype of the rotational energy harvesting system was built and this comprised a quadcopter, power management system and a charging system. Results from the test conducted on the system produced output power levels of 4.98W at a source rotation speed of 5400RPM, which is use to augment the primary power supply. In all about 30% more energy was harvested from 4 micro-generators connected in parallel. This translates to about 10 minutes increase in flight endurance, thus a gain of about 50% in flight duration.