[robocup-small] New Referee Box Protocol

Michael Eischer michael.eischer at robotics-erlangen.de
Tue Nov 13 15:28:56 EST 2012


> The timestamp is the timestamp of the packet, so it changes with each
> packet. The command counter only counts changes to the command, so it
> will probably only increment once every handful of seconds. It’s OK to
> lose a packet or two, as long as you don’t lose any commands. That’s
> why the counter only counts commands. The timestamp is there so you can
> properly interleave referee box packets with vision packets.
I've overlooked that a refbox command also includes status information 
not just commands.
However for proper interleaving (that is by the time the 
packets/commands were issued) of vision and refbox packets you'd also 
need the time when the refbox command(just ignore the status information 
for now) was originally issued. That is for the refbox command it 
doesn't matter when a team receives it. Instead it takes effect the 
moment it has been issued. As you can't guarantee that every team will 
receive a command the first time it's sent, it should also be 
accompanied with a timestamp that tells when it was issued.
Such a timestamp should be used in conjunction with the command counter, 
unless one assumes that there's always a delay of at least one 
microsecond between two commands. The timestamp could be used to 
synchronize timers f.e. for the free kicks time limit.

The command and the status information represent two different things. 
Just by listening to the commands you're able to infer the TeamInfos 
(except for red and yellow cards). In addition it's only updated once in 
a while. The team info on the other hand is updated with every packet 
sent. Thus I suggest to split these into two messages and join both in a 
wrapper message.

Just to mention it:
Why do we have a goal blue/yellow command but none for yellow/red cards? 
Both can be inferred from the team infos or be sent via a command (No I 
don't want a command for yellow/red cards). Seems to be a little 
inconsistent ;-)

Michael


More information about the robocup-small mailing list