Research

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Research

CUSL‘s research interest is in the areas of estimation, control, and dynamics of unmanned vehicles with an emphasis on unmanned aerial vehicles. Current focus is on vision-aided navigation, wind/gust estimation, cooperative control, remote sensing, and small UAV development.

Active Projects:

Small Unmanned System Development for Earth and Environmental Observations

Small unmanned autonomous systems can be deployed for different scientific research projects including but not limited to aviation safety research, atmospheric measurement, agricultural/environment monitoring, emergency response, etc.

KHawk - Flying Wing UAV

KHawk FlyingWing UAV Specifications Wingspan 48/55/81 inch Weight 4/6/8 lbs Cruise Speed 15-20 m/s Fight Endurance ~30/45/60 min Control Surface Two Elevens Power Electric Motor Take-off Bungee Payload GoPro Hero II Autopilot Papparazzi Autopilot

KHawk 48"-1 Flight Test

1. KHawk flying-wing-48 manual takeoff

2. KHawk Flying Wing 48 Auto-Circling

Wind/Gust/Wake Sensing and Suppression with Aircraft Formation Flight

Birds fly in V or echelon formations for energy saving as well as enemy defense. The follower bird usually flies in the wakes generated by the leader bird. However, it is unclear how exactly birds interact with the wake vortices during close formation flight. Small UAVs offer ideal platforms for further understanding of the interaction between the aircraft and the flow field such as wake vortices generated by the leader aircraft. Such researches could potentially lead to significant fuel saving of commercial flights and help decreasing the waiting time at airport terminals.

Former Research Projects:

Fusion of Optical Flow and Inertial Data for Short-Range Navigation of UAVs, NASA-Kansas-EPSCoR PDG, 2014

Optical flow has been used by insects and birds for navigation functions such as obstacle avoidance, speed regulation, landing, etc. It also has big potentials to support small UAVs for short-range navigation in GPS-degraded or GPS-denied environments.

• Publications
  • Rhudy, M., Chao, H., & Gu, Y. (2014). IEEE International Conference on Intelligent Robots and Systems (IROS). Wide Field Optical Flow Aided Inertial Navigation for Unmanned Aerial Vehicles. (Link)
  • Rhudy, M., Gu, Y., Chao, H., & Gross, J. (2015). Unmanned Aerial Vehicle Navigation Using Wide-Field Optical Flow and Inertial Sensors. Journal of Robotics, 2015, 251379. (Link)

Collaborative Stereo Vision Sensing with Small UAV Formation, NASA-Kansas-EPSCoR SIG, 2014-2016

The accuracy of most stereo systems are highly constrained by the short and fixed baseline between the two cameras. A group of small UAVs flying in formation with one camera mounted on each aircraft can function as one collaborative sensing system with adjustable formation offsets based on requirements from stereo vision sensing. After combining the collected stereo vision data with onboard inertial data, this system can then be used for real-time 3D terrain reconstruction during emergency response, mobile target detection, and obstacle avoidance.

• Publications
  • Zhang, M., Wang, G., Chao, H., & Wu, P. (2015). Fast and Robust Algorithm for Fundamental Matrix Estimation. In International Conference on Image Analysis and Recognition. (Link)
  • Chao, H., Brink, K., & Miller, M. (to appear in 2017). ION Pacific PNT Conference. Collaborative Stereo Vision Based Relative Pose Estimation with Small UAS Formation.
  • Chao, H., & Cheng, Y., (to be submitted). AIAA Journal of Guidance, Navigation, & Control. Collaborative Stereo Vision based Navigation Using a UAS Formation in GPS-Denied Environments.

Leader-follower formation flight of two KHawk UASs was achieved in Spring, 2016.

Preliminary visual odometry results and the 3D ground map is shown in the following figure.