Design of a human-machine cooperation system to facilitate skilled work

This study deals with a design method of a human machine cooperation system that facilitates work requiring a large amount of skill. For example, during cutting work a skilled worker seems to give a great deal of attention to the reaction force from a workpiece to his tool and little variation of characteristics of the workpiece, and seems to adjust his processing force and direction for accomplishing the work. Thereby an appropriate human-machine cooperation that amplifies human sensitivity to variation of characteristics of the object is able to make the work easy. At first in this paper, the human-machine cooperation system that consists of a human, a robot manipulator with a tool and a workpiece is represented as a block diagram. In the system the manipulator is position controlled from two force signals measured at the interface between the human and the manipulator, and between the tool and the workpiece. Then it is indicated that two typical characteristics of the system, transfer characteristics from human force to tool position and its sensitivity function to variation of characteristics of the workpiece, are independently specifiable. Therefore, for example, it is possible that the system is designed simultaneously to increase the human force enabling heavy work with a slight force, and to transfer a small variation of characteristics of the workpiece to the worker with amplification. Finally, some experiments are carried out on the human machine cooperation system that simulates some simplified work