Initial development of direct interaction for a transfer robotic Arm system for caregivers.

The most common injuries in healthcare are related to transfers. The Strong Arm system assists caregivers in providing fully dependent transfers from an electric power wheelchair to a bed, shower bench, toilet or other surface. However, this system currently controlled by buttons could be more successful with a more intuitive method during use. This paper presents the initial development of direct interaction for a robotic transfer system called Strong Arm. Direct interaction was used to make a transfer system more intuitive to operate using a three-axis load cell. To move Strong Arm, the user must apply intentional force on any of the given axes by surpassing the axis threshold. Unintentional movement could lead to injury. The results indicate that the thresholds for each axis were at least 3.5 N in X, 16.9 N in Y and 5.3N in Z in order to prevent unintentional forces from a human hand that would cause the robot to move.