Design of screw fastening tool based on SEA

Abstract

Screw fastening is often involved in industrial automation assembly processes. During the automatic assembly process in the industry, utilizing the electric screwdriver improves greatly the assembly efficiency. However, the powered screwdriver produces a large impact force on the work piece as he downward screwing speed and rotational speed are fast, which results in fatal damage to the work piece. This paper mainly designs a screw fastening tool to decrease the large impact force between the screw head and the work piece when the screw is driven at fast downward speed and the high speed rotation. This tool designed is based on SEA (Series Elastic Actuators) and adopts two-stage control strategy. By analyzing the experimental data, the tool can complete the function of screw fastening and can basically achieve the effect that the control strategy expects in the bolt fastening process. Within the tolerance of the error, the deformation of the rubber in the SEA has a good linear relationship with its output torque.