Downwash Detection and Avoidance with Small Quadrotor Helicopters

By using four independent rotors to provide lift and control moments, the quadrotor helicopter provides researchers with a small, mechanically simple and e↵ective vertical-flight platform. Typically, the lift and resultant torque due to each rotor can be approximated with simple aerodynamic models. Although these models have proven to be adequate in low advance-ratio flight conditions [1], they cannot account for the flow conditions associated with high-speed flight or the presence of large disturbances such as wind gusts or downwash from nearby rotorcraft. Real-time measurements of the flow-field around a flying vehicle provide a description of the flight conditions that would otherwise be impossible with only inertial-based instruments. This paper introduces a pressure-probe flow measurement system developed for a small quadrotor. The design, fabrication and calibration of the instrumentation package are presented along with data from autonomous flight trials using motion-capture-based positioning data. As a demonstration of the capabilities a↵orded by onboard flow sensing, a strategy for avoiding the downwash of a neighboring rotorcraft is proposed and demonstrated. Assimilating vertical flow-field measurements with a Bayesian estimation algorithm detects and localizes the source of vertical flow disturbances for use in a flight-path planner developed for proximity flight. The path planner minimizes a cost function that drives the vehicle to a desired waypoint while avoiding the Research Associate, Department of Aerospace Engineering, dyeo@umd.edu , AIAA Member. Ph.D Candidate,Department of Aerospace Engineering, nsydney@umd.edu , AIAA Student Member. Willis H. Young Jr. Associate Professor of Aerospace Engineering Education, Department of Aerospace Engineering, and the Institute for Systems Research dpaley@umd.edu, AIAA Senior Member. Computer Scientist, Naval Research Laboratory, donald.sofge@nrl.navy.mil , AIAA Member.

[1]  Ou Ma,et al.  Development of a Small UAV with Autopilot Capability , 2011 .

[2]  Thomas Corke,et al.  Stall detection on a leading-edge plasma actuated pitching airfoil utilizing onboard measurement , 2009 .

[3]  Robert W. Deters.  Performance and slipstream characteristics of small-scale propellers at low Reynolds numbers , 2014 .

[4]  Derrick W. Yeo,et al.  Onboard Flow Sensing for Downwash Detection and Avoidance with a Small Quadrotor Helicopter , 2014 .

[5]  Anthony Tzes,et al.  Constrained-control of a quadrotor helicopter for trajectory tracking under wind-gust disturbances , 2010, Melecon 2010 - 2010 15th IEEE Mediterranean Electrotechnical Conference.

[6]  Waqas Khan,et al.  Improvement and validation of a propeller slipstream model for small unmanned aerial vehicles , 2014, 2014 International Conference on Unmanned Aircraft Systems (ICUAS).

[7]  Craig Cox,et al.  Flight Test of Stable Automated Cruise Flap for an Adaptive Wing Aircraft , 2009 .

[8]  Stephen Todd Lion.  Control Authorities of a Distributed Actuation and Sensing Array on a Blended-Wing-Body Uninhabited Aerial Vehicle , 2007 .

[9]  R. E. Brown,et al.  AIRFLOW SENSORS IN THE AVIAN WING , 1993 .

[10]  Michael Gewecke,et al.  Breast Feathers as an Air-current Sense Organ for the Control of Flight Behaviour in a Songbird (Carduelis spinus) , 2010 .

[11]  Chuan He,et al.  Autonomous Sensing and Control of Wing Stall Using a Smart Plasma Slat , 2006 .

[12]  Simon Watkins,et al.  Development and Flight Testing of a Turbulence Mitigation System for Micro Air Vehicles , 2016, J. Field Robotics.

[13]  Clark N. Taylor,et al.  A Fixed-Wing, Mini-UAV System for Aerial Search Operations , 2007 .

[14]  Anthony Tzes,et al.  Experimental model predictive attitude tracking control of a quadrotor helicopter subject to wind-gusts , 2010, 18th Mediterranean Conference on Control and Automation, MED'10.

[15]  Ella M. Atkins,et al.  Autonomous Guidance and Control of the Flying Fish Ocean Surveillance Platform , 2009 .

[16]  Maurice L. Albertson,et al.  Diffusion of Submerged Jets , 1948 .

[17]  L. Johnson,et al.  Nighttime UAV Vineyard Mission: Challenges of See-and-Avoid in the NAS , 2004 .

[18]  Fei-Bin Hsiao,et al.  The Design of a Small UAV System as a Testbed for Formation Flight , 2011 .

[19]  Taro Suzuki,et al.  A Small UAV for Immediate Hazard Map Generation , 2007 .

[20]  Waqas Khan,et al.  Development and Validation of a Propeller Slipstream Model for Unmanned Aerial Vehicles , 2015 .

[21]  A. Rabhi,et al.  Different linearization control techniques for a quadrotor system , 2012, CCCA12.

[22]  Charles E. Hall,et al.  UAV Flight Control using Distributed Actuation and Sensing , 2003 .

[23]  Vijay Kumar,et al.  Influence of Aerodynamics and Proximity Effects in Quadrotor Flight , 2012, ISER.

[24]  Ella M. Atkins,et al.  Aerodynamic sensing for a fixed wing UAS operating at high angles of attack , 2012 .

[25]  F. White.  Viscous Fluid Flow , 1974 .

[26]  Z. J. Wang.  Nature’s Flyers: Birds, Insects, and the Biomechanics of Flight , 2007 .

[27]  Derek A. Paley,et al.  Dynamic control of autonomous quadrotor flight in an estimated wind field , 2013, 52nd IEEE Conference on Decision and Control.

[28]  Timothy W. McLain,et al.  Autonomous Vehicle Technologies for Small Fixed Wing UAVs , 2003 .

[29]  Derek A. Paley,et al.  Onboard Flow Sensing For Downwash Detection and Avoidance On Small Quadrotor Helicopters , 2015 .

[30]  이동욱.  12. M & A , 2000 .

[31]  Chih-Ming Ho,et al.  Micro balloon actuators for aerodynamic control , 1998, Proceedings MEMS 98. IEEE. Eleventh Annual International Workshop on Micro Electro Mechanical Systems. An Investigation of Micro Structures, Sensors, Actuators, Machines and Systems (Cat. No.98CH36176.

[32]  Adam Huang,et al.  Flexible shear-stress sensor skin and its application to unmanned aerial vehicles , 2003 .

[33]  Ella M. Atkins,et al.  An Empirical Model of Rotorcrafy UAV Downwash for Disturbance Localization and Avoidance , 2015 .