Conceptual Design and Feasibility Test of Foldable Robotic Arms for Collaborative Work: FRAC

A new type of wearable robot is introduced to provide supplementary arms for assisting the worker's tasks. The supplementary arm is metamorphic called Foldable Robotic Arms for Collaboration (FRAC) to extend the operational degrees-of-freedom. FRAC provides additional two arms for a worker to augment the tasks with the environment where the additional arms are necessary. Initially, the FRAC is folded for saving the workspace to allow more space for human arms to interact with the environment. It is unfolded when the worker needs extra arms to hold the object. The strategy for assisting the worker is described, and kinematics and simulation analysis of the folding and unfolding are performed. FRAC is developed for its feasible functionality by performing the conceptual drilling and screwing operation for construction work with the FRAC.