Maneuvering a bed sheet for repositioning a bedridden patient

The marionette bed presents a new method for rolling and repositioning a bedridden patient using a pair of actuated rollers attached to both sides of the bedsheet in order to lift and manipulate the patient body. This prevents development of painful bedsores and of pneumonia. This paper builds a simple kinematic model to create trajectories for generation of desired body motion. It also addresses a closed loop control strategy, based on patient position and orientation feedback, for the marionette bed. Closed loop control provides flexibility and safety in the various modes of operation of the bed. The bed can now handle patients of various sizes when supplied with some parameters. The safety of the patient is also ensured because the position and orientation is continuously monitored. A prototype is built and initial experiments demonstrate that a human body is rolled and manipulated by the assist device, as desired.