Angle measurement for balancing robot.

[Darrel Taylor]

>> Any chance you see some way to improove it?

Actually, yeah, I've got a couple ideas. I'll post them in the other thread.

But, back to the Balancing Act.
Did you use it in place of the Kalman filter, or with it?

Just curious.

[HenrikOlsson]

Hi Darrel,
Nope, the Kalman filter (if I ever understand/get that to work) would be used only to track the absolute angle of the robot platform. (Basicly removing the gyro drift). The error (desired angle - actual angle) is then fed to the PID-filter which in turn tells the motor-driver how fast the wheels needs to spin to keep it upright (or whatever).

As it stands at the moment (with the SHARP sensors) it just subtract the front sensor reading from the rear sensor reading and sends that value the PID-filter.

Thanks

/Henrik Olsson.

[uffi]

For those of you interested, I put here the link to my internet homepage, where you can find videos and description of my two-wheel balancing robot named ARTIST.

http://home.arcor.de/uffmann/ARTIST.htm

Have fun, Dirk.

[bbarney]

don't know if this is the answer but check it out
http://www.austriamicrosystems.com/0...ons_AS5043.htm

[HenrikOlsson]

Hi,
Thanks! Unfortunatly it won't work. That sensor outputs a value based on how a magnet placed in front of the sensor is rotated.

/Henrik Olsson.

[bbarney]

I just ran across it by mistake and remembered your post and thought maybe it would work,some interesting stuff there though

[RodSTAR]

I suggest that you use a third wheel.

You will not need to write complex coding and save a lot of coding space and parts.

LOL that's innovative !!

[RodSTAR]

Well,
interesting project, in fact i did that some years ago with stepper motors, hardware talking, you must combine both sensors accelerometer and gyro, aswell as obvious other sensors for not to mess with walls and other more complex obstacles. I applied kalman in C, in those times, I'll try to give myself a time to work in a PICBasic version to share it and adapt it to some new personal proyects I have in mind. Added also a digital compass to test gyro's Z response. Calibration and software compensation is the goal for this. Neural implementation for this, is the way to be taken.

Regards
Rodrigo,
RodSTAR

[HenrikOlsson]

Hi Rodrigo,
I haven't worked on the robot for several months. I did get it to balance a bit with the two SHARP sensors but the goal is to use the gyro and acceleromter. I beleive the Kalman filter is an esential part of the equation to get that to work correctly. If you ever get to porting any of your Kalman code to PBP I'd very much appreciate if you'd share it.

Thanks!
/Henrik Olsson.

[flipper_md]

Found this track about Kalman, and it looks quite a Maths challenge!

http://fred.unis.no/Kalman/Master_Thesis_Mathieu.pdf

very well detailed, but still complex.


this looks a bit more accessible: KalmanFilterforDummies
http://bilgin.esme.org/BitsBytes/Kal...6/Default.aspx

[Kamikaze47]

Sorry to drag up an old thread, but did anyone ever manage to get a Kalman filter implemented successfully in PBP?

I'm hoping to apply a Kalman filter to accelerometer and gyroscope readings to obtain a tilt measurement and I figured I'd ask if someone has done this in PBP before attempting to port the C code full of floats and matrix multiplication into PBP.

[HenrikOlsson]

Hi,
Not me.... But I'm sure it can be done with PBP, PBPL provides enough bits to get the resolution and but to be able to do it you need to actually understand how it works - which I don't :-(

If you understand the Kalman theory and/or how the C code works I'm sure that we, collectively, can work it out if we take it step by step.

I'd really like to see working Kalman filter in PBP as well.

/Henrik.

[Kamikaze47]

I've been researching it and i'm starting to understand it better. I can certainly follow the C code, but theres a lot of things in there that arent so easy in PBP, like floats, matrix manipulation and trig like arcsin.