New technique to help drones manoeuvre safely in mountains

Scientists have developed a new technology that can allow unmanned aerial vehicles (UAV) to manoeuvre safely in plateau mountain regions.
The UAVs designed for plateau missions are usually installed with high span chord ratio wings, which provides more lifting force at a relatively low airspeed.
The UAVs employ high span chord ratio wings, however, tend to lose their manoeuvrability. Hence, they usually need larger turning radius and are unable to maintain the altitude during sharp slope turning as the lifting force produced by the wings decrease dramatically when the bank angle is large.
The discarding of the flight performances may risk the safety of the flight in plateau mountain regions.

Variable thrust direction (VTD) technology is a type of thrust vectoring control (TVC) approach that allows to manipulate the directions of thrust to the fuselage of the aircraft.
Most of the existing works are designed for jet engines, which cannot be applied to the conventional propeller engine aircraft.

Researchers from Nanjing University of Aeronautics and Astronautics in China developed a novel VTD mechanism to the conventional propeller engine UAV, which allows redirecting parts portion of the thrust from the propeller engine to other directions rather than normal axial direction.
A combination flight controller for the VTD enhanced UAV is then proposed to coordinate the VTD controlled forces and aerodynamic surfaces forces.

The proposed variable thrust direction mechanism consists of a conventional propeller engine which is mounted on a two dimensional rotate disk driven by two servo actuators.
By combining the linear motions of the actuator, both the azimuth and the altitude angle of the disk with respect to the fuselage can be controlled, and thus changing the thrust direction of the propeller.
By the introduction of the VTD capability to the conventional propeller UAV, the manoeuvrability of the UAV has been greatly enhanced, since the VTD engine enables direct force control of the aircraft.
The newly developed VTD UAV was applied to implement plateau missions, which demonstrates the usefulness of the proposed technique.

The research was published in the journal Science China Information Sciences.