  This work proposes an autonomous docking control for nonholonomic constrained
mobile robots and applies it to an intelligent mobility device or wheelchair
for assisting the user in approaching resting furniture such as a chair or a
bed. We defined a virtual landmark inferred from the target docking
destination. Then, we solve the problem of keeping the targeted volume inside
the field of view (FOV) of a tracking camera and docking to the virtual
landmark through a novel definition that enables to control for the desired
end-pose. In this article, we proposed a nonlinear feedback controller to
perform the docking with the depth camera's FOV as a constraint. Then, a
numerical method is proposed to find the feasible space of initial states where
convergence could be guaranteed. Finally, the entire system was embedded for
real-time operation on a standing wheelchair with the virtual landmark
estimation by 3D object tracking with an RGB-D camera and we validated the
effectiveness in simulation and experimental evaluations. The results show the
guaranteed convergence for the feasible space depending on the virtual landmark
location. In the implementation, the robot converges to the virtual landmark
while respecting the FOV constraints.
