UAVs with Disaster-Aid Applications Feasibility Study

Introduction and Problem Definition

The 2017 Hurricane season was the deadliest in over a decade, and with an increase in hurricane frequency and intensity predicted, emergency response times will be hindered by physical barriers such as severe flooding. To optimize the process of disaster relief, organizations such as the Red Cross and the UPS foundation are collaborating with drone manufacturers such as CyPhy Works to adapt UAVs for disaster assessment. The goal is to create tethered drones that can identify water damaged homes and locate priority damage areas inside the disaster zone. The UAVs must be capable of transporting and delivering an 18-kilogram payload, which includes essential items for human survival. The stakeholders have a common desire for a fast and effective UAV service, while Metric Engineering and governments will consider cost effectiveness to a lesser extent. The model assumes that storm conditions have ceased, and wind conditions are negligible, and that the load of the UAV is uniformly distributed across the body.

Model and Analysis

Payload

This section outlines the calculation process for determining the maximum payload capacity of a UAV for delivering emergency supplies during natural disasters. The payload includes various items, such as iodine tablets, food, water, a life jacket, a safety manual, and a first aid kit. The total weight of the payload is approximately 18 kg, and the report emphasizes the importance of ensuring that the maximum payload capacity is greater than this weight. The section also discusses the physical payload and winch system, which should be lightweight and of appropriate size. The dimensions of the box are specified, and the winch system will consist of a nylon rope with a length of 10 feet. The report briefly mentions alternative delivery methods but ultimately recommends the use of the winch system for safety and accuracy.

Propulsion

This section discusses the calculations needed to model a UAV's delivery of a payload to victims in a disaster-stricken area. The section includes two stages: vertical ascent and horizontal movement. In the vertical ascent stage, calculations were made to determine the total force of gravity and drag acting on the UAV, and the power required from the motors to make the ascent. The section also discusses the horizontal movement stage and the average horizontal thrust required to maintain velocity, as well as the air flows acting against the craft modeled using the Reynolds number. The report concludes that the craft can ascend in 90 seconds and travel 2 km to the rescue site. The required solution will be within the normal power output of the battery and produce exit velocities that do not risk human safety or property damage.

Navigation

This section discusses the navigation system of a UAV used for completing reconnaissance missions after a catastrophe. The system comprises a barometer, two radio transmitters, a GPS receiver, and a Position Sensing Detector (PSD). The UAV uses the method of trilateration to determine its position, and the navigation model displays the method of determining the UAV's position and how it is piloted. The report provides an example of Hurricane Harvey and how it affected a small town in Rockport, TX, to explain how to determine the UAV's location in a 2-D grid. The most prominent error in the method is the large distance needed for each signal to travel, which affects the accuracy of the GPS navigation.

Body Design

This section describes the design of a multirotor octocopter UAV for reconnaissance missions. The report describes the mechanics and body design of the UAV, which has eight arms and 16 motors and propellers, along with an inverted pyramid body shape. The section includes details of how the motors and propellers are connected in tandem, and how the arms are fitted with dampeners to reduce vibration. It also mentions the materials used for the body, carbon fiber and aircraft-grade aluminum, and the dimensions of the UAV. Finally, the section talks about the payload cutout and payload compartment, and how the payload will be connected to the UAV.

Conclusion

The report details the design of a UAV for disaster response, with subsections for payload, propulsion, navigation, and body design. The payload consists of essential items and a winch system to transport a thin titanium cube to a disaster site. The propulsion system uses 16 brushless DC motors to achieve vertical takeoff and horizontal flight, with a 10% margin of error. The navigation system uses GPS and other sensors to track the UAV's location and avoid collisions, with an estimated total distance of 4km to reach the drop zone. The body design includes an inverted pyramid shape with eight arms, each with two motors, and is made from carbon fibre and aircraft-grade aluminum. The report notes that the model relies on several assumptions, with an expected error of approximately 10%.