Gliding UAV Perches on a Wire -- Power Line Recharging to Follow

UAV (Glider) Perching on a Powerline

Perching is one of the most common aerobatic maneuvers executed by birds and is representative of a large and important class of aggressive aerial maneuvers that take advantage of unsteady aerodynamics.  During a perching maneuver, birds often exceed 90 degrees in angle-of-attack, exploiting both viscous and pressure drag for rapid deceleration.  Russ Tedrake and Rick Cory at MIT's Robot Locomotion Group have drawn inspiration from these insane maneuvers by developing a gliding UAV that can perform perching -- eventually (presumably) allowing a UAV to perch and recharge on powerlines.  This is an impressive feat on many levels:  the physics (semi-turbulent flow, visualized in their photos), a controls perspective (dealing with high-speed maneuvers, non-linear dynamics, and real-time constraints), and an application perspective (the eventual integration of powerline recharging).  Be sure to check out the photos and videos!

To quote the Perching Glider project page

The glider is launched at a random initial speed that ranges anywhere from 6.0 to 8.5 meters per second (13.5-19 mph) and begins 3.5 meters (12 ft) away from the perch. It must then quickly decelerate to a near stop before making the point landing, by attaching a small hook under its belly to the perch. In order to slow down fast enough, the glider must orient its entire body to a high angle of attack, allowing it to exploit both viscous and pressure drag for braking. The entire maneuver last just a fraction of a second and is computer-controlled by varying the angle of the tail.

A video of the perching glider:

Visualizing the fluid dynamics.  Note all that turbulent flow!


The detailed turbulent flow photos are simply beautiful.

Turbulent flow of a UAV glider
Turbulent flow of a UAV glider  Turbulent flow of a UAV glider


It seems that early systems performed all sensing offline via Vicon motion capture (see paper Experiments in fixed-wing UAV perching).  The idea of using inductive power harvesting from powerlines is not new in itself, but sensing the powerline's magnetic fields to hone in on its location is certainly clever (see paper Powerline perching with a fixed-wing UAV).  Tedrake et. al. have a number of additional academic papers on this topic:


You can find additional details on the Robot Locomotion Groups Perching Glider project page or the MIT press release.  


Evan Ackerman over @ IEEE Automaton just posted a cool video from the Utah Telerobotics Lab that shows a quadrotor with bird-like perching capabilities:

Quadrotor perches like a bird

Currently, the video (below) only shows the quadrotor statically latching onto the perch.  I'm sure this is fine for a quadrotor with nice, stable flight and descent.... but I wonder if a more compact leg mechanism could be used in conjunction with Tedrake's glider to "capture" the perch.  That would be mad cool!


—Travis Deyle