Echoic flow is a formula derived from natural phenomena that has the potential to control vehicles with great efficiency using range information. Initially studied in bats, echoic flow allows animals to use sonar as a navigation tool. Downward-facing echoic flow used in the vertical landing of an Unmanned Aerial System (UAS) has been studied in past research. Forward-looking echoic flow on a UAS could allow for new approaches to braking and following techniques in the horizontal plane of motion towards both fixed and moving targets. The goal of this project was to demonstrate forward-looking echoic flow guidance towards a fixed target using a quadcopter and to gather data showing the accuracy and precision of the process. In initial forward-looking tests, a modified Parrot AR Drone with an added ultrasonic sensor and Raspberry Pi were used as the UAS. Preliminary findings showed erratic and often inaccurate range finding measurements. These measurements were attributed in part to the inability of the UAS to aim directly at the small target. A software filter was designed to minimize the impact of erroneous measurements. Further tests conducted using a flat wall as the approach target still yielded trials that did not follow the ideal echoic flow approach accurately. In an attempt to improve the performance of trials, the equation used to convert velocities to motor thrust values was recalibrated. Though trial results did improve due to this modification, imprecise quadcopter movement control prevented the achievement of a smooth echoic flow approach. Finally, simulations of forward-looking trials were performed to test the impact of measurement and velocity error on the performance of echoic flow approaches. The values of measurement error that resulted in acceptable echoic flow performance were found to be lower than the expected values for the UAS in this study. Further forward-looking echoic flow research is recommended using a more accurate and robust rangefinder. A UAS capable of more precise horizontal plane movement is also recommended.No embargoAcademic Major: Electrical and Computer Engineerin
