[ros-users] Fuerte SIG 2.15: Efficient IPC for Robust Modularity

Mike Stilman mstilman at cc.gatech.edu
Wed Sep 14 04:09:38 UTC 2011

Dear ROS Users,

With tomorrow as the close date for ROS Fuerte Planning SIGs, I'd like to 
announce two projects related to significant increases in performance for 
robot control and simulation. They are now posted on the SIG sign-up and 
we would like to gauge your interest in collaborating on these features. 
I'll separate this into two emails since they are distinct SIGs.

SIG 2.15: Efficient Inter-Process Communication (IPC)
Currently, ROS solves real-time performance by running a single process. 
However, for system modularity of complex robots such as PR2 and humanoids 
it is desirbale to run multiple processes that represent hardware drivers, 
control systems, vision processing, planners and other algorithms. It is 
challenging to create such IPC in an efficient and robust way. The 
Humanoid Robotics Lab at GT has developed Ach which maintains data 
history, eliminates HOL Blocking problems is efficient, robust, and 
formally verified. This was originally motivated by achieving 1khz control 
for a humanoid robot, however it is written generally and should be 
applicable to real-time control systems as well as improving the 
efficiency of perception frameworks such as Ecto by assisting with 
zero/low-copy functionalty.

The goal of this SIG is to explore Ach among other solutions to ROS shared 
memory transport and broaden their usage for tasks that require 
efficient/robust communication. Ach is BSD and will appear as a ROS node 
shotly. It has run reliably on a variety of robots for years and has been 
used together with other ROS toos such as OpenCV / RViz / PCL running in 
the same process.

Further topics of discussion in the SIG would include tighter integration 
between IPC and ROS, perhaps even implementing Ach
as a ROS transport. Likewise, using the IPC to help mitigate latency in 
networked and wireless communications.

If you are interested, please shoot us an email
(ntd at gatech.edu, mstilman at cc.gatech.edu)
and sign up for SIG 2.15 at http://www.ros.org/wiki/fuerte/Planning

For more information on Ach, visit http://www.golems.org/node/1526
It contains BSD source code and example code to run it, as well as 
developer dox and a tech report explaining the software and the choices 
made so far during development.



Mike Stilman
Assistant Professor
Director: Humanoid Robotics Lab
Robotics and Intelligent Machines
Georgia Institute of Technology
email: mstilman at cc.gatech.edu
cell:  (650)283-4284

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