Surface wave actuators for tangential transport of humans

Bedridden patients and elastic bodies are transported by generating surface waves on an active bed. Surface waves are shown to be a viable transport mechanism for large-scale, elastic bodies given certain conditions and constraints on the design. Surface wave actuation allows a bedridden patient to move freely while lying comfortably upon the bed. The motion of each node on the bed surface is coordinated such that it follows a circular trajectory with a certain phase lag from adjacent nodes. Basic properties of surface waves are presented. Based on these properties a new, concept, the extender, is added to the design to take advantage to the inherent rotational component of surface wave points. Kinematic analysis is performed to characterize the actuation concept. Sensitivity of design parameters on critical human transport issues is presented. Transport speed and efficiency are analyzed as well. A proof-of-concept prototype is designed, built and tested. It is demonstrated that a human is moved along the bed surface while lying on the bed.