Discipline: Technology and Engineering
Subcategory: Aerospace Engineering
Room: Exhibit Hall A
Madeline Corrigan - Northwestern University
Co-Author(s): Joe Heimerl, Texas A&M University, College Station, TX; Farid Saemi, Texas A&M University, College Station, TX
Cyclocopters offer improved efficiency over traditional small unmanned aerial vehicle (UAV) designs, and because the axis of rotation is switched from vertical to horizontal with blades parallel to this axis, the unsteady flow over the blades creates unique aerodynamic characteristics. This research tests a single bladed cyclorotor in a water tunnel at Re ~100,000 to determine if the same aerodynamic effects, like dynamic stall and unsteady virtual camber, are present at larger blade chords and spans with a larger radius of rotation. While extensive work has been done validating CFD simulations against PIV results for Re ~18,000, the unsteady effects vary with Reynolds number, so we made some major modifications to the setup to produce enough torque and provide enough precision in controls to obtain accurate results at larger sizes with higher velocities. A stepper motor replaced the servo previously used to pitch the blade, and the blade was redesigned to withstand high torsional forces from the fluid flow. To control the system, we implemented a Position-Integral-Derivative (PID) control to ensure the stepper motor maintains accuracy and can be electronically coupled to the blade’s azimuthal position around its rotation. By downloading the PID control loop to the motor’s controller, we were able to successfully force the stepper motor to behave like a servo, but with added torque, higher bandwidth, and more positional freedom, and very little computational delay. This experimental setup will allow us to test the aerodynamic effects acting on the cyclorotor blade, and as our research into this matter continues, we will be able to determine with a high degree of certainty what forces are at play and how we can tune cyclocopter controls to account for them in the real world.
Funder Acknowledgement(s): We conducted part of this work under the auspices of the National Science Foundation (NSF) under grant number EEC-1560424. However, any views expressed in this paper do not necessarily represent those of NSF or its affiliates.
Faculty Advisor: Jacques Richard, firstname.lastname@example.org
Role: I designed and built the majority of the testing setup, including calculating the amount of torque needed to pitch the blade, designing and wiring the electronic setup, writing the code to control the motor, tuning the controls to account for mechanical issues, designing the blade to be 3D printed without introducing torsional failure, and designing and machining the linkages connecting all the parts. Now that the program is technically 'over,' I'm helping remotely to tune the code and ensure proper functioning, and once we start gathering data I will be assisting in analyzing the results and writing a paper describing them.