On Wed, 15 Sep 2010, Tully Foote wrote:
> SMACH is the recommended way to coordinate complex systems. actions using
> actionlib are commonly used as states within SMACH.
> actions are as you say very similar to services in their use but have more
> control and feedback. SMACH is designed to work as a coordination engine,
> strongly based on a state machine. SMACH has been designed that it is
> trivial to use an action as a state within a SMACH state machine. Thus we
> use SMACH and actionlib at the same time.
So why are they implemented in two separate code trees? Why do they not
share everything they could share? (Which is a lot, because coordination
with state machines _is_ coordination with state machines, whether inside
or outside of a certain context...) Legacy? Developer communication short
circuits? Bouncing egos? Not Invented Here Syndrome? :-)))
I'm joking of course, but I do wonder what the real differences are, since
I do not see the case for two fully separated libraries...
> Tully
Herman
>
> On Wed, Sep 15, 2010 at 5:52 AM, Enea Scioni <enea.scioni@student.unife.it>
> wrote:
>
> HI all,
>
> I'm following this topic but I'm also a bit confused..
> In order to manage the whole system, composed as hundreds nodes,
> should I
> use SMACH (instead actionlib)?
> What is the " best practice " that ROS suggest? When should I
> use actionlib
> and when SMACH?
>
> Starting from the documentation (and my experiments), in a
> nutshell I see
> actionlib more similar to a ROS Service, but with added
> features, as
> possibilities to receive a feedback, delete the request and so
> on; to do
> that actionlib use/implement an "internal" state machine in
> order to manage
> the communication protocol on topic between the Action Server
> and Action
> Client.
> Is it true or I'm making a mistake?
>
> Regards,
> Enea Scioni
> --
> View this message in context:http://ros-users.122217.n3.nabble.com/actionlib-design-questions-tp1468507p
> 1479561.html
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>
>
>
> --
> Tully Foote
> Systems Engineer
> Willow Garage, Inc.
> tfoote@willowgarage.com
> (650) 475-2827
>
>
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