Optimal control model for reproducing human rising movements from chair and its effectiveness verification

We have formulated an optimal control model that reproduces human rising movements from a chair. The model switches its dynamics at the time (switching time) when its body moves away from the chair, and optimizes its criterion function composed of three kinds of energy costs, a center-of-gravity cost, and an input cost. We clarify its fundamental performance in rising from a chair and discuss factors indispensable for reproducing the same rising movements from a chair as humans. Consequently, the following results were obtained: (1) experimentally measured rising movements from the chair were successfully reproduced by appropriately adjusting the switching time and the weight for the input cost; (2) there existed the optimum input weight value with respect to each switching time. These results suggest that the proposed model is effective as a model of the human rising mechanism from a chair and that the switching time and input weight can be factors involved strongly in human rising movements from a chair.