level flying?

[Joe2003]

hey

Just wanted to know what solutuions people have developed to get level flight using stamp/pic chips? What sensors are needed? The only way I can see it being done is a ton of mercury all at varying angles which is kind of a lame solution. I know the obvious answer is to use a co pilot system, but I think it would be better to have the whole flight system from a single unit .

[Joe2003]

CAn you use gyros?

[kd7ost]

Rate gyros won't work well for you. They "resist moving from any given axis or axes' in the case of dual gyros." They accumulate error. If you do end up with a wing a little high, or nose or tail high or whatever, the rate gyro will then tend to keep it from moving off that pitch or bank angle. It won't level the plane out.

Dynamic is the cheapest way to go. Inherent stability built into the airframe around a given axis.

Vertcal gyros will do it, (unlike rate gyros) but they're hard to find below $2,000.00 each.

Thermopiles work for most conditions and locations. The co-pilot is easy to integrate into the flight package.

You might concider, that co-pilot is not a stand alone device once installed. It, like all the other parts you integrate into an airframe become part of the whole UAV. At least in my thinking.

Dan

[Joe2003]

what do you mean by dynamic?

I just think its cheating abit if you use a co pilot system :o

[kd7ost]

what do you mean by dynamic?

By dynamic I mean inherent in the design. I'm not a fan of that myself. It means polyhedral type wings etc. It stays level because it is not designed to roll without yaw. I don't like the lack of control in that style of plane.

I just think its cheating abit if you use a co pilot system :o

Thats cool. Lots of guys here are doing a variety of things including some of the stuff your talking about. I'm not one of the smart guys that can interface a couple of thermopiles to a processor. I have to cheat or I don't get to fly. :D

Dan

[Terry S]

A sensitive rate gyro can be used set up to detect yaw but conected to the ailerons. As soon as the plane starts to bank it will turn and the gyro will roll it back level. In practice it dose need a positive stable airframe to make it return to dead level but it will stop any plane from entering a terminal dive. To steer the plane with gps you just need a small input to the ailerons and this will cause a turn at a rate proportional to the input.

Terry

[Joe2003]

hey terry, I see your from the uk. Where do you get all your stuff from, what gps are you using?

I was thinking about heading lock gyros too, but I think a co pilot would save alot of time. are they all ir horizon units?

[kd7ost]

A sensitive rate gyro can be used set up to detect yaw but conected to the ailerons. As soon as the plane starts to bank it will turn and the gyro will roll it back level. In practice it dose need a positive stable airframe to make it return to dead level but it will stop any plane from entering a terminal dive. To steer the plane with gps you just need a small input to the ailerons and this will cause a turn at a rate proportional to the input.

Terry

Terry is right here. I don't know of too many examples where it's been done at our hobby level though. Maynard Hill's design crew evidently used a rate gyro that wasn't a hobby gyro for the Atlantic Ocean crossing. It was set up to sense yaw but connected to the single aileron. This was as per an email from Maynard.

Also, the BTA AS-06 and 07 units do it too. http://www.maxxprod.com/mpi/mpi-16.html scroll down the page.


Dan

[Terry S]

Hi Joe2003, I get my stuff from anywhere I can ! Most from the internet but parts from the US, Germany, France and not forgetting the UK. My GPS is a Geko 201 connected to a PDC10. The co-pilot is the easy way to go but I use a michanical gyro with very weak springs fitted. Its also possable to angle the gyro up to 30 deg so it will react to roll as well as yaw but I have not done this.

Terry

[weg22]

Joe,

I'm not sure what your budget is? Gyros probably are your best solution! Yes, they will accumulate noise...but you can filter this out! If you have a technical background, you can apply a Kalman filter to the data. Or you can buy an IMU which usually includes gyros, accelerometers, and a built-in filter. This will output roll, pitch, and yaw angles which you then will feed into your PIC...where your control algorithm will adjust your rudder, elevator, and aileron surfaces accordingly to keep the plane level.

I used this setup to perform a 3D hover autonomously:
http://prism2.mem.drexel.edu/~billgreen/blackhawk/nsfDemo091605a.mpg

-weg