Assessment of operators' mental strain induced by hand-over motion of industrial robot manipulator

To improve productivity of assembly in cell production, human robot collaboration is introduced. In the collaboration, robot manipulator supports human operators by handing over an assembly part in the assembly process. However, when the human operator works coexisitently with the moving robot in close distance, it might induce high stress to the operator. This paper studies on strain measurement caused by the hand-over motion of an industrial robot, and discuss design criterions of the robot arm motion when working with a human operator. Several basic stresses are experimentally measured: motion speed at robot's movement, motion trajectory and so on. Experimental results indicated following two points. First, low motion speed (less than 500[mm/s]) or non-straight motion is preferred to design hand over motion which induce low mental strain. Second, it is recommended for a human operator to be notified of robot motion speed before it moves to avoid mental strain.