Date of Graduation

2017

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Lane Department of Computer Science and Electrical Engineering

Committee Chair

Roy S Nutter

Committee Co-Chair

Powsiri Klinkhachorn

Committee Member

Vinod K Kulathumani

Abstract

The recent proliferation of smaller and more affordable sensing and computing has contributed to an increased availability of unmanned aerial vehicles, UAV's. Specifically, quadrotor platforms have become popular due to their low cost, versatility, and relative ease of operation. There are a variety of applications for this type of aerial vehicle, ranging from hobbyist photography to search and rescue operations. This thesis documents the feasibility of using a quadrotor UAV within the confined space of an underground coal mine during an emergency. Additionally, this paper notes in the Appendix an experiment to remotely operate a quadcopter that is located underground. This work specifies the equipment used to operate down an eight inch borehole in terms of radios, fiber optic cables, and video hardware. The operator and quadcopter were located 50 feet apart in the experiment.;One of the most significant challenges of operating a quadcopter in an underground coal mine is collision avoidance. The automation of basic spatial centering in the underground coal mine would lessen the burden on the operator and help prevent collisions. Many spatially aware quadcopter systems already exist, but widely rely on GPS signals as a way to determine position. GPS signals are very weak radio signals that cannot penetrate into the earth. The below-ground nature of an underground coal mine precludes the use of GPS for positioning the craft. Due to this limitation, it became necessary to explore unique sensing solutions that would allow for the spatial centering of the quadcopter while operating in an underground environment.;The ability for the craft to maintain a distance from its surroundings through the use of a light-based sensor was analyzed. Sensors were placed on the bottom and side of the quadcopter, and the performance of the control system was observed. Altitude was maintained with a steady state error of 4%, and the response to a step change in ground height resulted in a 10% lower overshoot than simulation. Simultaneously, distance was maintained from the side with a steady state error of 7.8%. The work presented in this document serves as validation for the basic spatial awareness and crash avoidance capability of a quadcopter operating without GPS in an underground coal mine while controlled remotely down an eight inch borehole.

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