witricity legality?

[XXShadowXX]

I seriously want my team to do this next year but im sure about how legal it would be based on this and last years rules.
witricity is basically the cordless transmission of power. By using coils that resonate on the same frequency one will pick up the power that the other is broadcasting(no signals are being sent only electromagnetic waves), using this with victors it think would make a very sweet crap drive, but im not sure if it would be legal via this and last years rules.

thanks for the help
cody

[EricVanWyk]

Not to rain on your parade, but FIRST's rules are the least of your concerns. Physics and the FCC will stomp this many times over.

1) The drive train uses a lot of energy.
2) RF transmission is lossy.
3) The energy that leaks out will affect other systems.

Do you have any examples of this "witricity" as you call it? I'd be interested to see their numbers.

Cool idea though.

[XXShadowXX]

witricity which using resonating magnetic coils was proved possible my mit last year by using it to light a 60watt light bulb 2m away. With stuff blocking directing line of sight

also Tessala (can't spell) using witricity to transmit massive voltages over great distances, one example is that in a eletrical field you can light flourencent lights with out plugging them in.

the laws of physics allow this to work, but im not sure if the metal frame would interfere. Also other eletronics can work in a witricity feild if they don't opperate on the same frequency they will not conduct the current. Which is why you make sure that the cycles of the field is very high (10megahertz or higher).

MIT tested this device, there was 40% power loss in transmission. If we weren't going for speed this could be viable i think. You know for a engineering award.

[artdutra04]

You could also just build your own slip rings to transmit the power to the motors in the crab drive. It would most likely be a lot simpler.

[Jimmy Cao]

Originally Posted by artdutra04

You could also just build your own slip rings to transmit the power to the motors in the crab drive. It would most likely be a lot simpler.

Unfortunately, building custom connectors are not legal. Our swerve drive is limited to 8 rotations (on each wheel) and we looked into such connectors, but they cost upwards of $400

[artdutra04]

Originally Posted by Lostmage333

Unfortunately, building custom connectors are not legal. Our swerve drive is limited to 8 rotations (on each wheel) and we looked into such connectors, but they cost upwards of $400

Depending on how you actually design and implement it, they are legal if they make it through the electrical flowchart of legality.

[dtengineering]

Rather than planning this as a power transmission method for a FIRST robot drivetrain, where robustness and reliability are paramount, this sounds like a great science fair project.

If you do your research and start building prototypes and testing them now then you will not only have a good science fair project, but... if you can move more than 40 amps through the ether with minimal losses, then you will have something that your team can check against the FRC rules for legality.

Just keep in mind, however, that transmitting current is quite different from transmitting voltage. Also keep in mind that when a CIM is drawing 40amps at 10 volts, that is 400 watts of power. If you have a 40% power loss then you have 160 watts of heat showing up somewhere. Any compact, lightweight system is going to start getting really hot, really fast.

So if you are interested in this system, study it. Research it. Test it. And should you get it to the stage where you can use it in an FRC robot, then worry about what the FRC rules are. Even if it doesn't work for FRC, it will still be a very cool science fair project.

Jason

[Daniel_LaFleur]

I see no FIRST rule that would prevent the use of Witricity.

That being said, you still have a lot of things to overcome
1> Matching resonators for transmission and reception. Any impedence mismatch will greatly reduce your transmission efficiency.
2> Each device would need a separate frequency to transmit power.
3> You would need to make sure you do not induce any current in any robot frame on the field, to do so would break FIRSTs rules.
4> You would need to make sure you do not interfere with any signals on the field.
5> Power losses would limit your robot and multiple transmitters in series (Battery to dist block, dist block to Victors, Victors to motors, etc) would cut your power even more.

While I think your idea is novel, and would win you an engineering award, I don't think it would provide a viable robot on the field.

[roboxking]

Originally Posted by XXShadowXX

witricity which using resonating magnetic coils was proved possible my mit last year by using it to light a 60watt light bulb 2m away. With stuff blocking directing line of sight

also Tessala (can't spell) using witricity to transmit massive voltages over great distances, one example is that in a eletrical field you can light flourencent lights with out plugging them in.

the laws of physics allow this to work, but im not sure if the metal frame would interfere. Also other eletronics can work in a witricity feild if they don't opperate on the same frequency they will not conduct the current. Which is why you make sure that the cycles of the field is very high (10megahertz or higher).

MIT tested this device, there was 40% power loss in transmission. If we weren't going for speed this could be viable i think. You know for a engineering award.

You are correct, WiTricity is physically possible. however, probably incredibly destructive. Look at the nature of electricity and plasma. Plasmas (this includes fire and electricity) Plasmas in their nature are designed to destroy everything they get into contact with. The amount of energy require to transfer electrical potential is incredibly powerful, and can destroy not only human cells, but electrical circuits. everything in the path of these waves will be instantly destroyed. You can essentially kiss all of your electronic components good bye. And no, these cheap little electronic devices aren't made to withstand such a destructive force. Hope this clears up any notion to use such an experimental procedure.

[Daniel_LaFleur]

Originally Posted by roboxking

You are correct, WiTricity is physically possible. however, probably incredibly destructive. Look at the nature of electricity and plasma. Plasmas (this includes fire and electricity) Plasmas in their nature are designed to destroy everything they get into contact with. The amount of energy require to transfer electrical potential is incredibly powerful, and can destroy not only human cells, but electrical circuits. everything in the path of these waves will be instantly destroyed. You can essentially kiss all of your electronic components good bye. And no, these cheap little electronic devices aren't made to withstand such a destructive force. Hope this clears up any notion to use such an experimental procedure.

I need to correct a little here:

1> Witricity is RF, which is the transfer of electricity (electrons) through a medium in a specific frequency band. It is not conversion of that electricity (electrons) into plasma (charged ions).
2> Plasma is not inherently destructive. There are many factors that go into what plasma does. Energy levels, frequency, material being affected, etc. I use plasma all the time in surface treating applications where I work.
3> RF (like Witricity) is also not inherently distructive. You have RF going through you everyday. Cell phones, WiFi, Radio (including the RC radio), RADAR all use RF. There's also natural RF generators (our sun is a good example).

Now I'm not saying that Witricity would not be destructive. Properly implemented and controlled it could be very useful and nondestructive. The key is an understanding of the effects that the fields will have on the local enviroment and nearby objects. And "those cheap little electronic devices" ... you'd be surprised how much RF they can handle (at specific frequencies).

[Al Skierkiewicz]

Daniel,
One small correction, we are talking about electromagnetic energy in a certain frequency band.

[Daniel_LaFleur]

Originally Posted by Al Skierkiewicz

Daniel,
One small correction, we are talking about electromagnetic energy in a certain frequency band.

You are correct.

I don't generally differentiate between electromagnetic energy and electrcity because any movement of electricity within a medium creates a magnetic field (so for me it's an assumed thing).

Again, you are correct.

[Generalx5]

I havnt looked into this one bit, but does any one know where the power loss comes from?

After a quick wiki search...

It seems as if this technology is similar to transformers. either steup up or step down, so if the coils were identical, then theres no ups or downs but a direct transfer of energy via electromagnetic field. So...this makes me think that the 40% efficiency @ 7feet away conducted by MIT could have been more efficient if the two coils were close to one another....similar to a transformer. Is the high frequency necessary? I can feel the 60Hz "buzz" from my desk lamp if I put a metal object close to the base of the lamp. It doesnt seem to be affecting anything.....I will try a simple coil test right after I publish my post, Ill repost with the results form my Mastercraft Multimeter.


BRB!

[Generalx5]

Okay, so I see why they dropped the Witricity. As far as I can see, I didnt get any voltage, but I did get some current, 130mA was the average. As soon as I moved about 2cm awway I was down to only 20ma....Not a very good power supply... thats the end of that..

[Al Skierkiewicz]

Originally Posted by Generalx5

I havnt looked into this one bit, but does any one know where the power loss comes from?
BRB!

June,
There are a variety of places where the power is lost. Turning RF into an effective field is tough enough but then you add to that the power that is lost by not coupling all of that field to the receiving coil. The inefficient coupling between the coils due to a lack of focus of the field and the varying load on the receiving coil all add up as well. Certainly placing the coils closer together would help. The RF is used to make the coils small and light enough to be a practical demo. Lower frequencies would work but the coils become significantly larger for the same efficiency.