Natural trajectory generation for Robot-Human cooperation for sit-to-stand assistance

This paper presents a method to determine trajectory for robot that involves a close interaction between robotic systems and human beings.The proposed method considers robot trajectory as path in operational space and time rhythm distinct problems verifying the natural smoothness of voluntary human movement. Operational space path is determined experimentally as individual movement pattern. The human voluntary movement smoothness is quantified by a function: the jerk. Than, minimizing the time derivation curvilinear abscissa acceleration, we found the function of the time that defines the time rhythm along the trajectory. This method is applied on a robotic device like ”walking aid” developed in LRP to provide support during the walk and sit to stand transfer. During the verticalisation, the robot handles have to help the user to sit-to-stand more naturally as possible. Keywords—Assistive device, sit-to-stand transfer, minimum jerk, trajectory generation