Publication Date

2012

Document Type

Honors Thesis

Department

Engineering

Keywords

Airplane-Models, Drone aircraft, Gyrostabilizers, Atmosphere-Researcg, Meteorology-Instruments

Abstract

This project was a proof of concept for the development of a data logging and control system for an airborne atmospheric instrument. Unmanned aerial systems (UAS) provide lowcost opportunities for making low-cost in-situ measurements. Improved stability and control of UAS will allow for increased use by atmospheric scientists to characterize many atmospheric processes, including the exchange of carbon dioxide (CO2) between the surface and the lower atmosphere. This exchange helps quantify the sources and sinks of the atmospheric (CO2), giving scientists a better understanding of its rising concentration in the atmosphere. The aircraft developed for this thesis was stabilized with a 3-axis gyroscope to develop a linear feedback control system on the yaw axis, controlling the rotation rate to improve the user interface. The Gyro-Stabilized Aircraft (GSA) integrated chemical and meteorological sensors including the SenseAir K33 CO2 engine (K33), in collaboration with the Centre for Atmospheric Science (CAS) at the University of Cambridge, a relative humidity sensor, a thermistor, and an absolute pressure sensor to measure carbon dioxide concentration and meteorological conditions of the Atmospheric Boundary Layer (ABL). This electromechanical system was housed in the commercially available Multiplex EasyStar model aircraft. Two successful flights in the spring of 2012 validated the design of the GSA. The aircraft flew for six complete soundings in the late morning to evaluate the efficacy of the meteorological sensors. Characteristics of the atmosphere in the late morning include a high mixing depth and a nearly constant vertical CO2 profile; because the concentration of CO2 is nearly constant, this flight was used as an in-flight calibration of the K33. The second flight tested the proportional control algorithm. In flight, the aircraft completed four straight-line paths and was able to maintain a rotation rate of approximately 10 degrees per second (dps) for one ii complete circle at a near-constant altitude. While additional work needs to be completed to increase the stability of the aircraft and more accurately calibrate the CO2 sensor, these flights verified the effectiveness of the GSA for atmospheric measurements

Language

English

Comments

iv, 82 p. : ill. (some col.) Honors project-Smith College, Northampton, Mass., 2012. Includes bibliographical references (p. 47-50)

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