Two unmanned aerial vehicles (UAVs) hover over a building in Singapore. UAV one drops 20 feet and enters through an open window, while UAV two flies slowly above a fire escape until locating a point of entry. Both UAVs ‘instinctively’ avoid obstacles before taking position outside an office where gunmen hold hostages. The UAVs see it all, and real-time video is transmitted to a command center where a Singaporean SWAT team readies itself for action.
International students at the Naval Postgraduate School (NPS) are working with university researchers to make the above scenario possible. ST Aerospace, one of Singapore’s premiere defense technology firms, recently dispatched one of its engineers, Chee Nam Chua, to conduct graduate research on UAV flight technology at NPS.
“NPS is known for its defense technology,” said Chua. “Our company works with the Technology Defense System Institute (TDSI) from Nanyang University of Singapore. TDSI has been working with NPS for the last 10 years … There is no other institution where you can do defense-related research that compares to what you can get here.”
Chua hopes to utilize UAV flight algorithms developed by NPS Department of Mechanical and Aerospace Engineering Professor Dr. Oleg Yakimenko, the director of the university’s Aerodynamic Decelerator Systems Center (ADSC). If successful, these algorithms will allow Singaporean defense and law enforcement personnel to operate multiple unmanned aircraft in congested urban environments.
“The most important UAV capability that we are developing is Detect, Sense and Avoid (DSA) technology … UAVs should be able to detect potential threats, avoid collisions and implement an avoiding maneuver,” said Yakimenko. “All these steps, up to the generation of an avoidance maneuver, need to be done in a fraction of a second.”
Yakimenko ‘s research into UAV flight algorithms and airborne delivery systems is breaking ground in an area that has becoming increasingly important in the age of asymmetric, modern warfare – warfare that often occurs in populated areas far from the battlefields of the past.
“Military conflicts are shifting from jungles and deserts to cities. This is because terrorists and insurgents find that these areas provide rich target environments and good hideouts,” said Chua. “With the use of UAVs, urban threats can be tracked and targeted effectively.”
Singapore is a small, but densely populated, urban nation. Its overwhelmingly urban environment demands innovative defense solutions, and Chua and his colleagues aim to harness technology that will allow UAVs to ‘instinctively’ avoid obstacles in type of dynamic urban terrain.
“Operators will provide UAVs with a mission area, map, flight and altitude data … But the dynamic environment requires systems that can avoid obstacles without human direction,” said Chua.
“We are employing the Inverse Dynamics in the Virtual Domain (IDVD) method that allows computing feasible spatial trajectories to maneuver in a clutter dynamic environment,” said Yakimenko. “It is a proven concept and it has been utilized onboard aerial, ground, surface and underwater vehicles already.”
The concept can been seen in action at NPS’ Autonomous Systems Engineering and Integration Laboratory where UAVs buzz about the lab, avoiding obstacles and each other.
“My students use IDVD technology on quadrotors and Qbots [unmanned ground vehicles] … they have demonstrated a variety of collaborative missions involving up to four ground vehicles and four quadrotors,” said Yakimenko.
The aircraft (quanser qball quadrotors or quadrotors) are beach ball sized contraptions of interconnected tubes and braces housing a set of four propellers. When perfected, the algorithms developed by Yakimenko and his students will guide more sophisticated aircraft designed to find, reveal and disrupt criminal and terrorist networks.