Advanced patient transfer assist device

Abstract

A significant need has been identified for an improved device to assist in transferring mobility limited patients, particularly those who are heavier or bariatric. Typical transfers include moving between a bed, wheelchair, chair/couch, toileting chair or toilet, car, or the floor. Currently, clinicians suffer more disabling workplace injuries than construction workers or firefighters, many of which are attributable to moving patients. A new, cost effective, hydraulically actuated prototype patient transfer assist device has been developed and fabricated; hydraulic actuation has advantages in terms of force density over electrical actuators that are typically used at this power scale. More generally, development of improved methods for control of machines that work collaboratively with humans to maneuver heavy payloads, sharing a task and a workspace, are developed. With this improved control, restrictions requiring two or more caregivers to move a patient can be removed, providing additional savings. A simple, intuitive caregiver interface has been implemented, which provides coordinated rate control using a force sensing handle mounted near the patient for the operator input. The caregiver can interact directly with the patient, while simultaneously controlling the lift device. External interaction forces are managed to keep them in a safe range, in addition to smoothly controlling motion. An impedance control uses redundant sensing of obstacles, with feedback of both external interaction forces and proximity. Operator experiments indicate improvements over current market lifts in terms of operator ratings and speed of completion with reduced forces in case of a collision.