Physical Human-Robot Interaction Control with Human Behavior Comprehension

Physical human-robot interaction (pHRI) has attracted massive research interests, leading to advancements in robot hardware and control scheme development. Series elastic actuators (SEAs)-driven robots are popular for physical interactions owing to their natural compliance and safety. Existing control schemes for SEA-driven robots have been demonstrated in pHRI tasks with a specific objective and limited interaction forms. However, the pHRI tasks requiring flexible interactions for task completion have yet to be thoroughly investigated. To this end, this paper develops a unified controller to address flexible interactions based on comprehending unintentional and intentional behaviours. A biomimetic adaptation learning method estimates the human unintentional interaction force based on iteratively updating time-varying feedforward force, stiffness, and damping. Simultaneously, human intentional behaviour is recognized from interaction force, and the reference trajectory is accordingly deformed for task completion. Finally, several experiments are conducted on a two-DoF SEA-driven robot to validate the effectiveness of the proposed controller.