Force Simulation and Ergonomic Assessment of Electric Care Beds

This study aims at evaluating and predicting the feasibility of electric care bed (ECB). Subjective evaluation were utilized to quantify the usage limitation of ECB and depict direction of shear in the passive motion process, Two groups of people were asked to finish a series of experiments on two types of electric care beds. The results were utilized in a virtual man-bed system to assess the influences of posture, motion process and figure. In each posture, the model was divided into 25 closed parts to calculate gravity of body parts in all given postures in repeated circulation process. With pressure measured by pressure mapping and shear direction known, the force distribution in dynamic system can be estimated. Conclusions are drawn from results of both subjective evaluation and force distribution simulation. A series of recommendations are given to improve passive motion of bed boards basing on the conclusions. The simulation method can also be used to quantify complex force distribution and predict the feasibility of unprecedented functions or new postures provided by mechanical assistance to some extend.