Searching \ for '[PIC]: Rate-Sensor use for motion-control' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/microchip/ios.htm?key=sensor
Search entire site for: 'Rate-Sensor use for motion-control'.

Exact match. Not showing close matches.
PICList Thread
'[PIC]: Rate-Sensor use for motion-control'
2001\10\12@150346 by Protobyte Inc.

picon face
Greetings All....

Could use some input on a formula or any other
experience.......

Using a GyroChip-II "Rate-Sensor" and performing
an A-D (12-bit).  The data is combined with another
16-bit source (joystick-output) to produce a command
position value.  The value is then sent over to a PMD
(Performance Motion Devices) to operate the motor.

The joystick serves to position the axis, while the Rate-
Sensor acts to stabilize the axis (vibration, etc.)

I'm having a difficult time determining what calculation
I could use (within a PIC16F873) .......in assembly lang.

Any algorithms out there for such a task ?

Thanks!                Steve Kelley

__________________________________________________

PROTOBYTE INC.                       http://www.protobyte.com
14208 Zachary Dr.
Liberty, MO 64068                  
Email: spam_OUTinfoTakeThisOuTspamprotobyte.com
Phone: (816)-792-0235
Fax  : (816)-792-0595
___________________________________________________

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email .....listservKILLspamspam@spam@mitvma.mit.edu with SET PICList DIGEST in the body


2001\10\12@163801 by Olin Lathrop

face picon face
>>
Using a GyroChip-II "Rate-Sensor" and performing
an A-D (12-bit).  The data is combined with another
16-bit source (joystick-output) to produce a command
position value.  The value is then sent over to a PMD
(Performance Motion Devices) to operate the motor.

The joystick serves to position the axis, while the Rate-
Sensor acts to stabilize the axis (vibration, etc.)

I'm having a difficult time determining what calculation
I could use (within a PIC16F873) .......in assembly lang.

Any algorithms out there for such a task ?
<<

One of my current projects envolves dealing with real time gyro and
accellerometer data on a 16F877.  I do various analysis and filtering on the
data both in integer and floating point.  Beyond that I don't know what to
tell you because I don't understand your question.  Perhaps you could be
more specific.


********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, olinspamKILLspamembedinc.com, http://www.embedinc.com

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email .....listservKILLspamspam.....mitvma.mit.edu with SET PICList DIGEST in the body


2001\10\12@193906 by Brandon Fosdick

flavicon
face
Olin Lathrop wrote:
{Quote hidden}

It sounds like a controls question. Although that depends on why the PIC
is processing the inputs, which isn't very clear.

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email EraseMElistservspam_OUTspamTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body


2001\10\13@122246 by Protobyte Inc.

picon face
Brandon.......

You're right, I left out alot of details, because much
more is happening with the PIC's, that's not related
to the data-integration for producing the position
error.

The PIC utilizing the equation (or in need of one) is
actually working within a Master/Slave topology.

It happens to be the Slave and handles USART
& SPI data, as well as performing the integration.

The joystick data is received at 19.2K baud over
an async.-serial-port, using a 4-byte packet.  The
packet breakout is not important here, but it does
contain 16-bits of "position-information" that is used
to operate "one" axis through a PMD-Chipset.....
which then drives (via Sign-Mag) an LMD18200
H-bridge (as a Servo-motor).

The rate-sensor is located remotely and uses a
GyroChip-II Sensor, conditioned via 3rd, order
Butterworth (100hz. cutoff) and then passes to
a MAX-187  12-bit A-D.  We sample at 6250hz.
and the Slave gathers SPI data at 1.2mbs

Both the Rate-Sensor data and the joystick data
must be integrated to provide a single "position
error".  With the outcome being "two" independant
error sources, which when integrated have an
equal effect on the Servo's position error.  A scaling
of the two errors is necessary too.

Hope this shines more light.........it's about all that
I can disclose.

My "main" problem is lacking the ability to develop
assembly routines that perform much more than the
"basic-four", within a narrow time-frame of ~ 10 to 15
uSEC.  while operating at 20mhz. clock.

Also, I'm one of those that happens to be "C-challenged",
meaning ....... can't easily read/write it.  Thus, I work with
assembly only.  Of course, when my clone is ready, I'll be
sending him to school again......full-time.

So, now we come to the "nutshell"........
**********************************************************************
"I'm looking for assembly based algorithms, that can provide
integration functions and exceed the level of only basic math".
**********************************************************************

Regards,
                 Steve Kelley

P.S.  Where can I pick-up some singing potatoes ?
        They sound like easy "pets" to maintain  8^)


{Original Message removed}

2001\10\15@103315 by Don Hyde
flavicon
face
I would recommend giving yourself more time.  With your anti-aliasing filter
as it is, you have 72dB attenuation at 1600 Hz, which means that a 3200 Hz
sample rate will guarantee that all aliases are smaller than one
least-significant bit.

One more op-amp can get you to a 6th-order filter, and then you can get your
sample rate down to 800 Hz.

All this is assuming that your 100-Hz cutoff actually implies that you are
only interested in data below 100 Hz, which is probably pretty reasonable
for a gyro application.

I would heartily recommend downloading the FilterLab program from the
Microchip website.

When doing signal processing with a relatively arithmetically-challenged
processor like a PIC, step 1 must be to do a little work on the front end to
get the sample rate as low as possible.

> {Original Message removed}

More... (looser matching)
- Last day of these posts
- In 2001 , 2002 only
- Today
- New search...