Human Box Delivering Simulation by Subtask Division

This study addresses one solution for determining the optimal delivery of a box. The delivering task is divided into five subtasks: lifting, initial transition step, carrying, final transition step, and unloading. Each task is simulated independently with appropriate boundary conditions so that they can be stitched together to render a complete delivering task. Each task is formulated as an optimization problem. The design variables are joint angle profiles. For lifting and carrying tasks, the objective function is the dynamic effort. In contrast, for transition task, the objective function is the combination of dynamic effort and joint angle discomfort. For unloading, it is a reverse process of lifting motion. A viable optimization motion is generated from the simulation results. The joint torque, joint angle, and ground reactive forces are analyzed for the delivering motion which is also empirically validated.