Drones are becoming increasingly useful and commonplace—but one of their enduring problems is their limited flying time created by heavy batteries and inefficient propellers.
The smaller the drone is, the shorter its flying time will be. Quadrotor drones—a common and popular design—provide plenty of flying stability and reliability. But the smaller the drone, the less efficient those propellers are. Combine that with constraints on battery size and weight, and those small drones require recharging within a short time after they first take off.
A team of researchers at Flybotix, a startup of the Ecole Polytechnique Federale de Lausanne, has designed a drone that could potentially overcome that limitation.
Reducing the number of propellers by half enabled the team to make each propeller longer and more efficient, and helps to minimize drag. It also made the drone more energy efficient—and allowed the battery to last longer. In fact, the drone can fly twice as long as existing models. In addition, the ring structure improves the drone’s durability, enabling it to bounce off of obstacles without damaging its flight machinery.
But two-propeller drones are typically harder to fly and much less stable than their quadrotor cousins. Bouabdallah’s team compensated for this limitation by using a ring shape for the drone, with the propellers stacked on top of each other within it. The propellers move in opposite direction, resulting in improved stability.
Bouabdallah also developed a digital control system that uses an algorithm-powered stabilizer to offset the two rotating forces—using a transmission system inspired by helicopters. The algorithm calculates how much to offset the rotation and tilt of each prop for maneuvering—making the drone easy to pilot with a conventional remote control joystick.
The Flybotix team intends to test its drone by conducting inspections of dangerous and inaccessible areas—something the drone would be ideal for with its relatively small size and protective foam coating. After that, the company plans to introduce the drone in the Chinese market, where Flybotix generated positive feedback and important contracts at the CES Asia conference and the Venture Leaders China program.
According to Bouabdallah, the technology could be used for search and rescue, public safety, law enforcement and environments where miniaturized drones are needed.
Read more about developments in drone technology at Report Details the Role of Drones in Construction.