| Newsgroups |
gmane.science.robotics.orocos.user |
| Organization |
FAW Ulm |
| Message-ID |
<[email protected]> |
[email protected] wrote:
> Indeed, and making these "well-defined patterns" explicit would be a
> very important contribution! I feel that we can do with much less than
> the most generic state machine structure, and I also have the feeling
> that the minimal FSM interface that you want is the same as the one we
> want at the control level!
>
> If one has an interface to a state automaton that is "only" an external
> interface, _and_ it is doing the job in the context of robotics, than it
> is _very_ worthwhile to have this interface. At all levels.
Absolutely !
> Does your state interface rely on particular SmartSoft architectural
> design decisions?
Yes, keep the state interface as lean as possible to avoid restrictions on the
component internal architecture. This of course requires skilled component
builders (which however can be expected and they do not have to be more skilled
than with other approaches), but due to the communication patterns, which
control every external depency, we can still provide a component based approach
with properties of component architectures.
> That is similar to our real-time core design: the sequencing is
> "outsourced" to a component, such that the other components need not be
> coupled at all. The coupling is exactly and only through the sequencing
> engine. One single point of decision making!
Yes, at least to have a hierarchical system of decision making where the parent
node configures the space of possible configurations for its successors. Since
we have bounded resources in robotics, it is quite natural to have a
hierarchical approach which however does not mean that we can have different
masters in different situations !
> This is "the" TCL, which is now abandonned by its original developers?
> I guess the specific language is not so important, but the interface is.
> I guess IDL is not suited for describing this interface, is it?
TCL has been developed by myself and is not related to any other approach /
software using the abbreviation TCL as well. It is a task net based approach to
describe activities. IDL describes interfaces and could be used to describe the
interface used for configuration including wiring. An important remark: since I
use well defined patterns with well defined semantics there is nothing
interesting to describe at the level of IDL since all methods of the patterns
and their usage is well known. What one would need is a much more rich
description of the capabilities of a component. CIDL is a step into the right
direction, but does not contain anything describing timing behaviors e.g.
Developing a component description language based on XML would be an interesting
goal.
> This is also behind the Esterel/Orccad approach, as presented by Daniel
> Simon at the Leuven meeeting. Of course, this kind of functionality is
> quite natural in any sequencing component.
It is behind many different approaches which differ more or less with respect to
the used software technology or with respect to the used software environment.
Some are simple libraries, others like TCL are interpreters written in LISP.
What I think is important in the context of SmartSoft is the availability of
simple component interfaces which do not require specialized method calls for
every component simply to activate or deactivate a skill or do whatever with a
component. The "glue layer" has to provide something for every communication
pattern and thats it.
> Both approaches are fully complementary, I think. They just provide
> similar fucntionality at different levels and for different purposes.
> But I think they might have _a lot_ in common, so making this
> commonality explicit really interests me... That's the kind of things
> Orocos is about: finding common designs for many robotics "things".
Exactly !
Christian
>
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Christian Schlegel
FAW Ulm (Research Institute for Applied Knowledge Processing)
PO Box 2060
D-89010 Ulm
Germany
Tel. : ++49 (731) 501 8949
Fax : ++49 (731) 501 999
email: [email protected]
WWW : http://www.faw.uni-ulm.de/
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