Development Force Control of a Series Elastic Actuator to Excavator for Mechanization of Manual Work ^*

Automation can address labor shortage and enhance worker safety in construction. However, workers continue to perform majority of the work at construction sites that can be automated. Construction machinery require force control for automation, which can absorb external shocks and provide appropriate forces along with environmental forces. This study proposes a force-controlled excavator that fulfills these requirements by replacing the hydraulic system with a series elastic actuator (SEA). Few studies have applied SEA to large high-output construction machinery. We designed the structure of the SEA to deliver high output power in a compact form that can be mounted on an excavator. A 2.5-T class excavator equipped with this SEA is designed, which achieved a force resolution of 15–35 N at the tip. The effectiveness of this excavator in automating a major portion of the manual work is demonstrated.