Physical human-robot interaction by observing actuator currents

In this paper, an interactive control scheme is developed for physical human-robot interaction. The human interacts with the manipulator when it is stationary by applying impulsive forces in the form of push-and-pull. The magnitude and direction of the human force are estimated by observing the joint actuation currents. The reference position of the end-effector is updated based on the human-force information. The developed scheme does not use any force sensors, does not limit the interaction to any specific location, and uses very cheap and easy-to-mount current sensors. This paper shows that physical human-robot interaction can be achieved by using cheap equipment and well-known techniques that can easily be implemented on light-weight robots with back-drivable joints.