Wings are best suited for cruising along distances horizontally, while rotors assist an aerial vehicle in the vertical axis of things. This is why most recreational drones use rotors as opposed to military grade drones whose wings make them look more like traditional airplanes. It’s always been a delicate balance between the two, but now it seems that researchers at the Singapore University of Technology and Design have found a perfect sweet-spot which allows for both vertical hovering and horizontal cruising capabilities from one singular drone design. Meet THOR, the “Transformable HOvering Rotorcraft”.
At the International Conference on Robotics and Automation (ICRA) of 2017, the THOR presented its aerodynamic efficiency to the world. Since the THOR utilizes wings to cruise which then fold into functioning rotors to hover, this really is an all-in-one design that seems to work perfectly according to the video provided by the Airlab of Singapore University of Technology and Design. In the video below, you can see the various options offered by THOR, such as Hover Mode (with which you can “pitch” forward or backward, and “roll” left or right), the transition from Hover to Cruising Mode, Cruising Mode, and finally, the transition back to Hover from Cruising Mode.
If you haven’t quite figured it out yet, THOR generates its lift by spinning in place with its wings tilted at 180 degrees, just like a helicopter does. When it’s time to cruise, similarly to an airplane, the wings are aligned into place, allowing for more horizontally focused autonomy. According to IEEESpectrum, the researchers are currently calling the Hover Mode “H-MOD”, while Cruise Mode is being labeled as “C-MOD.” Have a look at the diagram below of the THOR drone in “H-MOD”, straight from the Singapore University of Technology and Design.
The most important part of THOR’s operations is clearly the transition of the wings and their degrees to the ground. In order to switch from Cruise to Hover, each blade must rotate by 90 degrees, and this has to happen mid-flight without any obstruction to the intended flight path or any other user-experience flaw. According to IEEESpectrum, this action is done by an actuator in THOR’s midsection. Apparently, THOR has been extremely reliable in this regard. According to the SUTD team, “the motors were strong enough to almost instantaneously break the craft out of H-MOD rotation and push the craft into translational flight.”
Once you’ve seen the video above and take a look at all the work this team of researchers has done, you can’t help but be impressed. This seems like a huge step forward in combining the two primary elements of a cruising aerial vehicle and a hovering one, which, when combined, could fuse together to become a new standard of UAVs. This definitely seems like the best of both worlds. Of course, these are the early days yet, and refinements are sure to follow. We can’t wait to see how this evolves over time. Stay tuned.