Re: Re: A nomenclature question

After reading the mail I think that I explained my question very bad. I will 
try to explain myself again.

It's a very nice thing to have a generic library. However, I think that it's a 
very dificult thing to implement and mantain. After reading the document:
http://www.orocos.org/kindyn-doc.html
it would be very nice to have some kind of objects that represent a Serial321 
robot, or a Parallel321 or a Scara.
It could be great to have some kind of:
move(myrobotSerial321,mycontroler,mypathgenerator,myendposition) 
my question is about that how I can define a robot to have a mathematical 
interface to play with?

I think that the nomeclature helps to define the homogeneous transformation 
matrices, but I think that always you will need to define SOME parameters to 
construct your representation of the robot. 

> I don't see the advantage of choosing TCS: not that it is bad, but
> what real advantage does it bring to make contributors learn a
> particular _convention_? 

I agree. But you always will need some kind of parameters in the 
implementation. For example. I would like to simulate, or I would like to 
construct a new 8DOF arm. I have my phisical prototype constructed with 
Mecano pieces, some kind of servos, and some control. I would like to make 
simulations and of the robot to experiment some control algorithm to after 
put it in the real model. I would like to construct my virtual model and I 
will need to caracterize this robot to play with. I will need to specifie the 
parameters. If I use some nomenclature or another maybe in thery will be not 
important, but I think that it could be important internally to have some 
kind of consistent library. 
> I notice this every year again with students:
> they just make lots of "formal errors"; take a look at the table on p
> 45 of that document and you will know why :-) 

Sure, it's not an obvious thing. I have made a lot of errors.

>  Just let a designer  define his coordinate frames in what seems the most 
> appropriate way  for a particular mechanism. 
This is very easy to say but very difficult to implement. 

> For that mechanism, the efficient  kinematics have to be coded anyway. And 
> for the "external" use of the  device, all that counts is the tool centre 
> point or end effector frame.

Yes and not. You maybe would want to know where is the 3th link because you 
have a constraint and that link cannot pass some dimension.


Leo