[Tutor] Python serial interface

[Francois Dion]

On Wed, Apr 1, 2015 at 11:01 AM, Colin Ross <colin.ross.dal at gmail.com>
wrote:

> Hi Francois,
>
> Thank you for the fast reply! I am looking to control a brushless servo
> motor (
> http://www.aerotech.com/product-catalog/motors/rotary-motors/bms-series.aspx)
> that drives a rotary stage.
>

These motors are not controlled by serial, you'll need a brushless
controller. In turn the controller might be or not serial, or ip or
something else altogether (PWM is typical). They do have an rs-422
connection, but that is for a feedback signal. So you are building a
feedback control system. If you google that and python you'll find several
useful references, including a design and analysis module (but not control):

https://pypi.python.org/pypi/control/0.6.6
http://sourceforge.net/projects/python-control/

Nothing out of the box for your application, obviously. Also, the motor
control itself will depend on the microprocessor hardware you are using and
the motor controller. Assuming PWM, the raspberry pi has a software PWM
module in Python. Same with micropython. Anything else is pretty much DIY.

As for the overall concept of control systems, Chapter 9 of "Real World
Instrumentation" ( http://shop.oreilly.com/product/9780596809577.do ) will
give you an overview of what is involved (with some python example, but not
directly applicable to your system).

Francois
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