COMAU open control - a first reply

Herman Bruyninckx wrote:
> 
> On Mon, 8 Jan 2001, Basilio Bona wrote:
> 
> [...]
> > have acquired a COMAU Smart S2 Robot with an "open" C3G control.

> Great! How do you evaluate the openness of this approach? (Other
> manufacturers, such as ABB and KUKA also offer `open' controllers, but
> these are limited to sample frequencies of about 80Hz, and with dead
> times of several tens of milliseconds... I've heard that the Comau
> thing is better; is this correct?

In the normal industrial use, this robot is controlled by its own
Controller,
provided by the manufacturer with its software and control algorithm.

Using the PC-C3Link software, it is possible to 'open' the Controller
and 
use a PC to control the robot. 
The data exchange between the Controller and the PC is obtained by means 
of an interrupt signal generated by the Controller. Both the type of
data 
exchanged and the frequency at wich the interrupts are generated depend 
on the selected operating mode. 

We can divide these modes in 2 groups. 

Using an operating mode of the first group, the PC can interact with the 
controller at trajectory generation level, at a frequency of 50 Hz.
The Micro Interpolation and the Axes Position and Speed Control of 
the Controller are used. This means that the user can generate
trajectories
but cannot change the control algorithm.

Using a second group operating mode, the PC interacts with the
Controller
at a joint position control level, at a frequency of 1 KHz.
Using one of these modes, most of the Controller is disabled and the
user
is responsible for most of the control functions. 

It must be noted that in these modes, the user has the total control of 
the robot. This means that the user can choose the control algorithm 
but has also to consider the standard safety checks since they are 
not anymore performed by the Controller, like for example the Overspeed
or the Overcurrent check.

Due to safety reasons, these last modes can be activated only upon
explicit 
request by the customer.

As said in a recent mail, we have not yet used these two modes, so we
have
no direct experience.

Best wishes to all Orocosian

-- 
Basilio Bona
Professor of Industrial Robotics 
DAUIN - Politecnico di Torino
Corso Duca degli Abruzzi, 24
10129 Torino, Italy

tel +39 011-564.7023 
fax +39 011-564.7099
http://ladiserver1.polito.it/robotica/Curriculum/bben.htm