EMG Controlled Soft Robotic Bicep Augmentation

Abstract

Repeated lifting tasks are often required of industrial workers. Such repetitive loading of workers’ arms throughout the workday can lead to injury and fatigue. This paper details the development and prototyping of a wearable soft robotic device to augment a worker’s arms by sensing and mimicking the contractions of their arm muscles. The device shares lifting loads with the user’s muscles to increase their lifting capacity, thereby preventing injury and reducing fatigue. The human arm contains many muscles that coordinate to produce movement. However, as a simplified proof of concept, this project developed a prototype to augment just the biceps brachii muscle since it is the primary pulling muscle used in lifting movements. Key components of the prototype include a soft robotic actuator analogous to the biceps, a control system for the actuator, and a method of attaching the actuator to the user’s arm. The McKibben-inspired pneumatic muscle was chosen as the soft actuator of the prototype. The Electromyography (EMG) and pressure sensors are used to inform a hybrid control algorithm combining PID and model-based control methods. The method and results of the design and preliminary feasibility testing of the pneumatic muscle, the controlling algorithm, and the overall prototype are discussed in this paper. Based on these results, a wearable EMG controlled soft robotic arm augmentation could feasibly increase the endurance of industrial workers performing repetitive lifting tasks.