There has been a lot of work over the last few years to produce omnidirectional MAVs that use fixed tilted rotor platforms and tilt-arm rotors. While they can achieve a significant wrench generation, they do so with the same amount of internal force — hence it lowers the MAV’s flight efficiency. When it comes to tilt-arm MAVs, they can achieve high omnidirectional force with great hover efficiency, but at the cost of weight, inertia, and additional complexity.
To overcome those issues, researchers from Zurich’s (ETH) Autonomous Systems Lab have designed a microdrone that features omnidirectionality without any degradation in flight efficiency — meaning it can fly/hover in any position and orientation without losing its flight efficiency.
The secret to the VoliroX’s omnidirectional pose lies in the combination of rotors and arms, as the researchers designed the MAV with six tiltable arms- each with two KDE2315XF-885 brushless motors and 9-inch propellers on each arm. Actuating each arm is done using Dynamixel XL430 servo actuators, which are housed at the base to reduce inertia.
The upper and lower propellers counter-rotate, canceling out the drag torque and minimizes the gyroscopic moment on the arms tilting mechanism. An Intel NUC i7 does all the computational heavy lifting while a PX4 flight controller maintains position and attitude while operating. The MAV is powered by a pair of 3800mAh 6s LiPo batteries, which can be tethered for long distance near-horizontal flights. The researchers feel the VoliroX MAV is perfect for 3D mapping and aerial filming, as well as configuration-based navigation in confined spaces.