Wearable robots for performance enhancement of occupational workers

Wearable robots are robotic devices worn over the human body to assist during physical activity. They are broadly classified as soft exosuits and rigid exoskeletons. The upper limb robotic devices, worn over the human arm(s), augment during lowering, lifting, and operating power tools during overhead tasks. Upper limb wearable robots for industrial workers have shown potential in the recent decade. Specifically, passive upper limb wearable robots have been shown to reduce muscle activity and fatigue during overhead tasks. This chapter reviews the existing upper limb wearable robots, including their classification, mathematical modeling, control, and evaluation methods. First, a mathematical model is presented for the human arm and wearable robot to understand their respective kinematics and dynamics. Furthermore, the control architecture of the wearable robot is discussed. The wearable robot control is hierarchical, with a high-level and low-level controller. The focus of the high-level controller is on achieving more significant objectives, and the low-level controller focuses on ensuring that the actuators implement instructions of the high-level controller with minimum error. The physical interaction between the human arm and the robot is called the physical human–robot interaction (HRI). The robot’s controller includes the human intent with the help of sensor inputs, so the human arm motion and the robot output can be synchronized to have a better physical human-robot interaction (pHRI). The quality of pHRI is evaluated based on musculoskeletal parameters such as muscle activity, perceived exertion, range of motion after wearing the robot, and changes in the metabolic consumption of the user. However, wearable robots that are robust and highly effective for common use in industrial settings are yet to arrive. The leading cause for this could be the inability of the wearable robot to synchronize the robot’s response with the human motor control output.