Dynamic modeling of an upper limb hybrid exoskeleton for simulations of load-lifting assistance

Abstract

Work-related musculoskeletal disorders (MSDs) are among the most commonly reported issue in Europe. Using robotic exoskeletons to support users in performing heavy industrial tasks can effectively mitigate the work-related MSDs. In this paper, a dynamic model of a hybrid exoskeleton is presented to analyze the assistive effect. The exoskeleton in this study is able to passively support the human shoulder joint and actively support the human forearm movements by providing different levels of assistive torque. With the model, two different tasks are simulated, i.e., an overhead lifting task and a static load transferring task. The results show that the assistive torque provided by the passive spring-loaded mechanism reduces the maximum human upper arm effort by 22.65%. Moreover, the exoskeleton elbow joint’s assistive torque reduces the peak torque of human forearm from $10.12$  Nm to $5.1$  Nm. All these results demonstrate the efficacy of the model developed in the simulation and analysis of human-exoskeleton systems.