Finding Distance From Driver Station

[Mark McLeod]

It'd be kind of interesting. You'd only be able to derive the radius of an arc from the field AP from this method. Probably a distance of 10 to 60 feet, so even with a best error of +/-12 feet it won't place you in one of this year's zones.

You'd only want to ping the AP (an 10.0.0.x address) if you can to eliminate other network latency from throwing off your results. For your tests at home pinging your wireless router at 10.xx.yy.4. That'll be a nice experiment that you don't have to confine to the dimensions of an FRC field.

[mwtidd]

I guess my goal of trying to do it without breaking any rules isn't going to work.

Also I would be trying it with multiple access points, and this phase would just be to get the architecture in place for this kind of triangulation. I don't want to do it via WLAN, but the cRIO zigbee module is $700, and I don't have $2100 kicking around to produce a zigbee triangulation set up, as much as I would love to (anyone have grant money to do such a spike?? haha). Maybe I'll purchase some zigbee chips and try it that way. http://www.trossenrobotics.com/biolo...x?feed=Froogle ($25 a sensor)

http://ieeexplore.ieee.org/stamp/sta...umber=04463608

Thanks for all the feedback everyone!

(Hence why I switched from EE to CS )

[RyanCahoon]

I don't think this qualifies as thread-jacking as I think it still applies...

What about putting a beacon light on your driver station and using the camera to locate it? If you talked to your alliance partners and got the teams at stations 1 and 3 to each have a light, you could triangulate position using two cameras.

--Ryan

[mwtidd]

Originally Posted by RyanCahoon

I don't think this qualifies as thread-jacking as I think it still applies...

What about putting a beacon light on your driver station and using the camera to locate it? If you talked to your alliance partners and got the teams at stations 1 and 3 to each have a light, you could triangulate position using two cameras.

--Ryan

Think we could use the beacons that already exist??

The red vs blue would be real nice cause you could look at either side.

Good idea!

[davidthefat]

Why not just software localization? Just keep track of where you are through software

[RyanCahoon]

Originally Posted by lineskier

Think we could use the beacons that already exist??

The red vs blue would be real nice cause you could look at either side.

Ooh... Sounds like I have a new offseason project

Good idea, yourself

Originally Posted by davidthefat

Why not just software localization? Just keep track of where you are through software

Maybe I don't understand what you're suggesting; you would be using software to detect the position of the lights from the camera images and triangulate your position.

If you're suggesting (the fairly standard method of) dead-reckoning using encoders/accelerometers/gyros, the advantage to the methods talked about in this thread is that you can determine absolute position on the field, whereas relative localization has accumulated error since at each point in time you're only calculating the change in position, so successive errors in the sensor readings lead to increasing errors in the position estimate.

--Ryan

[mwtidd]

Originally Posted by davidthefat

Why not just software localization? Just keep track of where you are through software

Take this years game for instance, all sort of disorientation would occur when you cross the bump. So by having a absolute reference, you could re-initialize your position based on that reference. At that point you could switch to a sensor-driven localization similar to what your suggesting.

It kind of like zeroing a gyro based on a compass when you suspect drift.

[DonRotolo]

Thinking in a different direction: If you were on the field, how would you find your location?

If it were me, I'd just look around, find objects I recognize, and estimate the distance to two or three of them by their relative size in my field of vision.

Turning that into a machine function, you can have your camera rotate until it finds your home driver station wall (this assumes you are able to see it). Hand each of your alliance partners a battery-powered flashing LED, each with a different blink pattern. Your camera sees the blinks, knows which one is where, and calculates location based on separation between LEDs (how close or far apart they are) and angle based on camera rotation.

Sure, there's a few issues to address. For example, what to do when you're up against the driver station wall. Perhaps four Maxbotix distance sensors can help there. Whatever, these issues can be solved.

The point is, consider how nature does this, and emulate. Nature usually has a pretty good algorithm.

[mwtidd]

Originally Posted by Don Rotolo

Turning that into a machine function, you can have your camera rotate until it finds your home driver station wall (this assumes you are able to see it). Hand each of your alliance partners a battery-powered flashing LED, each with a different blink pattern. Your camera sees the blinks, knows which one is where, and calculates location based on separation between LEDs (how close or far apart they are) and angle based on camera rotation.

This was the idea behind looking at the driver station lights.
Also these lights are on either side, so you would just have to look to one side or the other, thus it wouldn't be side dependent. By seeing all 3 beacons in one scan you could tell where you were.

I think its relatively the same idea.