> Hello,
> I am new at this forum and this is my first post.
> We are trying to control some servos with a microcontroller Olimex
> lpc2103.
> We managed to make all the necessary software and hardware, and everything
> is working fine.
> There is just one problem - there is some noice in the servos when turn on
> the transmitter.
> We decied to make some filter, but when we use the Kalman filter it works
> too slowly.
> I just wonder if anyone could share some information about Kalman filter
> with whole numbers, not float numbers.
> I would really appreciate if anyone can share such an information.
First: What everyone else said. Unless there's something about your
setup that precludes getting the root problem fixed, trying to fix this
in software is just throwing money in a rat hole.
Second: Are you _really_ making a _real_ Kalman filter, or are you just
making a low-pass filter and calling it a Kalman? Kalman filter design
proceeds from understanding your processes, including your noise
processes, and helps you to design the optimal filter for your
situation. It does _not_ guarantee that the best possible filter is
good enough, it is, as Rudy Kalman formulated it, limited to being
optimal for Gaussian noise and a mean-squared error criterion, the
design is often way more complex than needed, and for SISO systems it
usually devolves down to something simple like a regular old lowpass,
bandpass, or whatever.
In general, when you're designing a filter for an unknown process you
use an alpha-beta filter
(http://en.wikipedia.org/wiki/Alpha_beta_filter) or a lowpass. Then you
play with the parameters to see if you can get things working nicely.
As far as integer math -- if you stick to a simple lowpass filter the
implementation details should be more clear than a textbook Kalman
(whose implementation is complex to reflect the complex problem you're
solving, and can often be simplified at the expense of all hope of
clarity). Then the means of implementing it with integer or fixed point
math should be clear.
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html
Reply by Chris H●December 1, 20102010-12-01
In message <z7WdnZ8f1dsSj2jRnZ2dnUVZ_oGdnZ2d@giganews.com>, onelife
<vasil@n_o_s_p_a_m.ics-bg.com> writes
>Hello,
>I am new at this forum and this is my first post.
>We are trying to control some servos with a microcontroller Olimex
>lpc2103.
Just to be picky... I think you will find NXP do the LPC2103
Olimex just make dev boards.
>We managed to make all the necessary software and hardware, and everything
>is working fine.
BUT.....
>There is just one problem - there is some noice in the servos when turn on
>the transmitter.
I think you need to work out how to remove the noise... not hide it with
SW
--
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
\/\/\/\/\ Chris Hills Staffs England /\/\/\/\/
\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
Reply by RCIngham●December 1, 20102010-12-01
>Hello,
>I am new at this forum and this is my first post.
>We are trying to control some servos with a microcontroller Olimex
>lpc2103.
>We managed to make all the necessary software and hardware, and
everything
>is working fine.
>There is just one problem - there is some noice in the servos when turn
on
>the transmitter.
>We decied to make some filter, but when we use the Kalman filter it works
>too slowly.
>I just wonder if anyone could share some information about Kalman filter
>with whole numbers, not float numbers.
>I would really appreciate if anyone can share such an information.
>Thanks in advance
>
Solving an EMC problem in software is like banging screws in using a
chisel!
;-)
---------------------------------------
Posted through http://www.EmbeddedRelated.com
Reply by Michael Kellett●December 1, 20102010-12-01
"onelife" <vasil@n_o_s_p_a_m.ics-bg.com> wrote in message
news:z7WdnZ8f1dsSj2jRnZ2dnUVZ_oGdnZ2d@giganews.com...
> Hello,
> I am new at this forum and this is my first post.
> We are trying to control some servos with a microcontroller Olimex
> lpc2103.
> We managed to make all the necessary software and hardware, and everything
> is working fine.
> There is just one problem - there is some noice in the servos when turn on
> the transmitter.
> We decied to make some filter, but when we use the Kalman filter it works
> too slowly.
> I just wonder if anyone could share some information about Kalman filter
> with whole numbers, not float numbers.
> I would really appreciate if anyone can share such an information.
> Thanks in advance
>
>
>
>
> ---------------------------------------
> Posted through http://www.EmbeddedRelated.com
There are always exceptions but usually the solution to a noise problem from
a well defined source like a transmitter in your equipment is to solve the
problem by either dealing with the source of the interference (power supply
coupling, out of band radiation etc) or stopping your input ciruits from
picking it up (analogue filters, screened cables, good earthing, screened
covers, small ciruit loops etc.)
Only when these basic solutions have been investigated should you resort to
attempting to filter out the problem in software.
Michael Kellett
Reply by onelife●November 30, 20102010-11-30
Hello,
I am new at this forum and this is my first post.
We are trying to control some servos with a microcontroller Olimex
lpc2103.
We managed to make all the necessary software and hardware, and everything
is working fine.
There is just one problem - there is some noice in the servos when turn on
the transmitter.
We decied to make some filter, but when we use the Kalman filter it works
too slowly.
I just wonder if anyone could share some information about Kalman filter
with whole numbers, not float numbers.
I would really appreciate if anyone can share such an information.
Thanks in advance
---------------------------------------
Posted through http://www.EmbeddedRelated.com