  Age-related loss of mobility and increased risk of falling remain important
obstacles toward facilitating aging-in-place. Many elderly people lack the
coordination and strength necessary to perform common movements around their
home, such as getting out of bed or stepping into a bathtub. The traditional
solution has been to install grab bars on various surfaces; however, these are
often not placed in optimal locations due to feasibility constraints in room
layout. In this paper, we present a mobile robot that provides an older adult
with a handle anywhere in space - "handle anywhere". The robot consists of an
omnidirectional mobile base attached to a repositionable handle. We analyze the
postural changes in four activities of daily living and determine, in each, the
body pose that requires the maximal muscle effort. Using a simple model of the
human body, we develop a methodology to optimally place the handle to provide
the maximum support for the elderly person at the point of most effort. Our
model is validated with experimental trials. We discuss how the robotic device
could be used to enhance patient mobility and reduce the incidence of falls.
