Improving the Maneuverability of Power Assist Valves by Considering the Characteristics of Biarticular Muscles

A number of studies have focused recently on the musculoskeletal systems of the human arm and foot with the support of human-machine systems. These studies aim to evaluate the performance of manipulators or analyze human characteristic. We focus on the fact that some postures reduce the effort necessary for the application of force from musculoskeletal systems. In this research, we apply the system to a power assist system. Using a musculoskeletal model, we propose the Compensation Considering Posture ( CCP ) method, which adjusts the assist ratio and consequently the applied force in accordance with the arm position of the operator. Then we apply it as a one link manipulator to a standard valve used in firefighting operations. In this regard, operation responsiveness changes when output force is reduced with the correct arm position. CCP improves valve maneuverability by providing additional assistance in such cases, and ensures that operation responsiveness is uniform regardless of arm position. To experimentally verify the proposedmethod, we firstmeasure the armposition of the operator in real time by using a musculoskeletal simulator. Next, we quantitatively defined the reduction of the output force according to the arm position as an output force level. Finally, we determine the appropriate amount of compensation by normalizing the force applied with the maximum output force level. The effectiveness of this method is experimentally confirmed using visual tracking.