RE: Modelica

> From: Henrik I. Christensen [mailto:[email protected]]
> Subject: Re: [Orocos] Modelica
> 
> 
> Hi Herman and Michael
> 
> Modellica is likely to be a very good starting point for system
> modelling, but it is not at all obvious that we can use current
> implementation of Modelica like Dymola. We will need to integrate
> Modellica with other tools so as ot be able to use it not only for
> system specification but also for execution and monitoring which poses
> addition requirements. In addition we will likely have to consider the
> integration of hybrid dynamic systems / embedded systems where
> implementation specifications enters into the specification and at
> present Modellica to my knowledge is too abstract to cover the actual
> transfer to a real platform. Thus we might be able to use Modellica as
> a starting point but we would need to go beyond Modellica.

My area is not robotics so I am not really familiar with the existing tools in this area or the existing specification formats.  I would point out that Modelica includes a very nice feature called "annotations" that allow you to embellish a Modelica description with additional details that are tool specific.

Because this is not my area, I am struggling to understand what the deficiencies are.  Do you have a "design objectives" document anywhere that describes, in a broad sense, what you hope to achieve with this project?

> As indicated by Herman we would also want to see an implementation in
> terms of speficiation that adhers to XML, which is a fairly easy fix
> and it would be easy to do a conversion both ways between MOdellica
> and XML. This the OROCOS Robodellica might be a "superset" on
> Modellica. 

As I pointed out in a separate message, it would be possible to serialize the AST from a Modelica parser into XML (actually, I know of a group that is already attempting to do that).  That being said, I think that approach is somewhat awkward.  It is not clear to me why XML is so important for this project.  Is there some absolute requirement that all details be written in XML?  If so, what is the justification for this?  I understand it is easy to parse and there are many tools available, but it seems to me that an "absolute" requirement would ignore the fact that it would have to be weighed against the existing tools and intellectual content of existing specifications.

> Henrik

--
Mike