With so many open-source repositories offering ROS libraries, we'd like to highlight the many different robots that ROS is being used on. It's only fitting that we start where ROS started with STAIR 1: STanford Artificial Intelligence Robot 1. Morgan Quigley created the Switchyard framework to provide a robot framework for their mobile manipulation platform, and it was the lessons learned from building software to address the challenges of mobile manipulation robots that gave birth to ROS.
Solving problems in the mobile manipulation space is too large for any one group. It requires multiple teams tackling separate challenges, like perception, navigation, vision, and grasping. STAIR 1 is research robot built to address these challenges: a Neuronics Katana Arm, a Segway base, and an ever-changing array of sensors, including a custom laser-line scanner, Hokuyo laser range finder, Axis PTZ, and more. The experience developing for this platform in a research environment provided many lessons for ROS: small components, simple reconfiguration, lightweight coupling, easy debugging, and scalable.
STAIR 1 has tackled a variety of research challenges, from accepting verbal commands to locate staplers, to opening doors, to operating elevators. You can watch the video of STAIR 1 operating an elevator below, and you can watch more videos and learn more about the STAIR program at stair.stanford.edu. You can also read Morgan's slides on ROS and STAIR from an IROS 2009 workshop.
In addition to the many contribution made to the core, open-source ROS system, you can also find STAIR-specific libraries at sail-ros-pkg.sourceforge.net/, including the code used for elevator operation.