Two-Dimensional Symmetric Box Delivery Motion Prediction and Validation: Subtask-Based Optimization Method

Abstract

Box delivery is a complicated manual material handling task which needs to consider the box weight, delivering speed, stability, and location. This paper presents a subtask-based inverse dynamic optimization formulation for determining the two-dimensional (2D) symmetric optimal box delivery motion. For the subtask-based formulation, the delivery task is divided into five subtasks: lifting, the first transition step, carrying, the second transition step, and unloading. To render a complete delivering task, each subtask is formulated as a separate optimization problem with appropriate boundary conditions. For carrying and lifting subtasks, the cost function is the sum of joint torque squared. In contrast, for transition subtasks, the cost function is the combination of joint discomfort and joint torque squared. Joint angle profiles are validated through experimental results using Pearson’s correlation coefficient (r) and root-mean-square-error (RMSE). Results show that the subtask-based approach is computationally efficient for complex box delivery motion simulation. This research outcome provides a practical guidance to prevent injury risks in joint torque space for workers who deliver heavy objects in their daily jobs.

Upper Extremity Joint Torque Estimation Through an Electromyography-Driven Model

“…The motion capture system was comprised of 8 Eagle-4 cameras with 10 retroreflective markers placed on the right arm during each task as shown in Figure 3 (Motion Analysis Corporation, California, USA). Details on the motion capture environment are explained in [30,31]. Analog EMG signals were recorded with Trigno Wireless Biofeedback System (DELSYS Incorporated, Massachusetts, USA) containing 16 surface EMG sensors.…”