Collaborative Robotics for Rehabilitation: A Multibody Model for Kinematic and Dynamic Analysis

Human-Robot Collaboration is increasing in industrial settings because of the robot’s accuracy and repeatability join perfectly with human’s problem solving to enhance the industrial productivity. Collaborative robots share the workspace with operators in order to reduce human workload and guarantee performances. The reliability and safety of these robots allow their application in the health care sector (e.g. neuromuscular rehabilitation). The cobot-assisted therapy is becoming a significant supplement to the traditional one aimed at providing intensive and repetitive rehabilitating tasks to improve the patient’s recovery. The human-robot system presented in this paper is a closed kinematic chain composed of a robotic arm attached to the human forearm through a custom handle system. The handle, designed with simple components, is used for primary rehabilitation exercises. The kinematic models of human and robotic arms presented in this study are applied to develop trajectory planning algorithm in the joint space. Robot joints torques needed for guiding the patient limb are obtained by multibody dynamic simulations, assessing the capability of the manipulator to perform the task at given speeds and loads. The tools and methods proposed in this work allow for a preliminary study on cobot-assisted-therapy by different human-cobot-working modalities.