Patent ID: 8573335

Claim:
A robot comprising: a robot chassis having a forward end, a rearward end and a center of gravity; a support surface moveably connected to the chassis and configured to propel the robot chassis; a trailing arm rotatable about an axis located rearward of the center of gravity of the robot chassis; and a controller configured to execute a stair climbing control routine stored on the mobile robot, including causing the robot to perform operations comprising: driving the support surface over an underlying surface towards a stair; pivoting the trailing arm downward against the underlying surface and causing the forward end of the robot chassis to raise up off the underlying surface, the trailing arm having a distal end that contacts the underlying surface forward of the center of gravity of the vehicle; further driving the support surface to cause the forward end of the vehicle to ascend a riser of the stair, the support surface generating sufficient traction against the riser to climb the riser as the support surface is driven; and pivoting the trailing arm so that the distal end contacts the underlying surface at a point behind the support surface while the robot ascends the stair.