Novel human-centric force control methods of power assist robots for object manipulation

Abstract

We propose two novel human-centric force control methods for a power assist robot for lifting objects with it by the human. For this purpose, we developed a 1 DoF experimental power assist system for lifting objects. We included human's weight perception in the robot dynamics, and derived two novel force control methods for the system. We then implemented the force control methods separately. For each control method, the subjects lifted different sizes of objects with the system at different conditions, and evaluated the performances of the system. The performances were expressed in terms of perceived heaviness, force and motion features, safety, stability etc. We analyzed the performances and the results showed that both of the novel force control methods produced satisfactory performances of the assistive system though the performances varied between the control methods. We then proposed to use the findings to develop control methods for human-friendly power assist robots for manipulating heavy objects in industries that may improve productivity, man-machine interactions, and human's health and safety.