Hizook (Travis Deyle and Robert Powers) have found some fascinating research:
We were scanning through the upcoming ICRA2012 program and noticed an interesting paper titled, "Resonant Wireless Power Transfer to Ground Sensors from a UAV." This certainly piqued our interest -- especially for Travis, who happens to work with wirelessly-powered sensors at his day job. Come to find out... the article is by Dr. Carrick Detweiler, PI of the NIMBUS Lab at the University of Nebraska-Lincoln (our undergrad alma mater!). Furthermore, he just provided a preprint of the paper (PDF) and a video on his website. Score! Their quadrotor delivers power via magnetic resonance (ie. WiTricity-style) to a load on the ground. This same type of technology is being actively researched for lots of applications, including: consumer electronics, transportation (eg. electric vehicle recharging), and remote sensing (this application). Adding it to a UAV adds a bit of flexibility to the system. Anyway, be sure to check out the video below... and we'll also give a brief overview of a few different wireless power + robotics projects over the ages.
The paper is titled, "Resonant Wireless Power Transfer to Ground Sensors from a UAV" (PDF) by Brent Griffin and Dr. Carrick Detweiler.
Magnetic resonance can be a good method for wireless power transfer at medium distances (ie. a meter or so). Owing to the resonant fields, it is more efficient that inductive coupling, which would require the UAV to be in close proximity to the load (a few centimeters) to get good mutual coupling. Furthermore, the magnetic fields are less susceptible to occlusions or material composition compared to microwave (electromagnetic) or laser-based wireless power transfer.
However, being at least partially familiar with the underlying technology, we know that alignment and (dynamic) frequency tuning are absolutely critical for efficient power transfer using magnetic resonance. Presumably, the quadrotor itself could supply the necessary flexibility in the system to help align the coils -- heck, we've all seen quadrotors perform impressive feats of acrobatics. So kudos to Carrick and Brent for their insights!
Lots more history on this kind of power transfer at the rest of the post here.
Comments
Back to the original topic . The more things change the more they stay the same Lower the frequency and the distance for wireless power transfer increases along with potential .Crystal radios are Wireless power transfer they
work over distances of hundreds of miles In the last few discussions above between Munroe and I about "free power "we are only talking 60 cycles or Herts for you young guys
Thanks ! EagIe I needed that ! In many ways Munroe and I are on the same page
I Know what you are thinking Munroe go for it ! Charley was quite a guy he had a piper super cub . He would be flying along "Declare an Emergency" and land on the on ramp to the service center along the free way and go in for a coffee. a lot of times the police would show up before he was done . He would say "Let me take the plane over to the far end of the service center so it is out of the way ."As soon as there was 350 clear feet in front of him he was GONE!
Hers one for you guys a fellow pilot Charlie Olden who is deceased now and had a air strip on his farm. Out back of his farm the high voltage transmission towers ran parallel with the back of his property One day Charley was out fixing his fence and got a shock from the fence .I checked it with the volt meter to ground there was some serious current .We ran 2 iron wire 600 feet long 30 inches apart on stand off insulators and got induced 230 v ac from the transmission lines 50 feet away and He powered his farm free for 20 years . It wasn't until Ontario Hydro got a sensor on their helicopter and were able to fly along the power lines that could sense shorts and hot spots lines and stray eddy currents that they found it . Thy never charged him for stealing
electricity but they made him take it down on the premise if some body climbed the fence they might get zapped ! You guys have a good day!
Can't believe no-one in Nebraska thought of grappling the receiver coil & hanging during the power transfer. This could be the technological miracle that finally allows Oklahoma researchers to surpass Nebraska researchers.
I think the reverse would be more useful. Maybe a fully autonomous scenario where the UAV preforms security patrols around a building then returns to its home location for charging.
Travis here -- one of the Hizook post authors, and a researcher in this field.
The key thing about wirelessly-powered sensors being queried by a UAV is that (1) the UAV can get to inaccessible locations that are normally tough to reach and (2) the sensors don't need a battery-pack (again, because they're tough to reach). An example... perhaps you want strain gauges measurements from many different locations on a large bridge. A UAV could fly up, supply power, and make LOTS of measurements from embedded sensors. [If anyone is interested in this... we're building the wireless power, comms, and sensor systems for this exact purpose (and others). Just ping me on Hizook's contact form.]
As for powerline perching and recharging... there is already a project for that: http://www.hizook.com/blog/2010/07/20/gliding-uav-perches-powerline...
That's something for DARPA to figure out.
Greg, that was my impression too. It would be much more useful to be able to charge the quad rather than something ground-based, but on the other hand it would appear pretty counter-effective to do it while flying! I wonder if your idea is feasible...
I guess that's good for a learning exercise, but to me it looks like a solution without a problem. Now if you could get a copter to hang(perch like a bat) on a high voltage power line, could it couple enough to recharge its' batteries and fly on, or collect data for a long time? Like an energy sucking vampire bat(they don't take much).