Analysis of force feedback mirror-assisted strategy based on adaptive impedance control

Abstract. When rehabilitation robots assist patients with unilateral upper-limb motor dysfunction in mirror-assisted exercise training, the lack of bilateral tactile feedback may lead to secondary injury on the affected side. To address this issue, a force feedback mirror-aided strategy based on adaptive impedance control is proposed, utilizing a bimanual robot. This strategy establishes a force feedback mirror between the unaffected and affected sides, allowing the unaffected side to perceive the assistive force when the manipulator assists the affected side's movement, thereby ensuring the safety of the mirror-assisted exercise. To achieve mirror trajectory tracking during rehabilitation, a human–robot physical interaction model is developed based on the robotic dynamic model and impedance control. For tactile feedback between the unaffected and affected sides, adaptive impedance control is employed based on the interaction force between the affected side and the manipulator, ensuring that the interaction forces on both sides are proportional and equal in real time. Experimental results demonstrate that, during bilateral mirror-assisted exercise, force feedback mirrors are effectively formed between the two arms, confirming that the proposed strategy not only enables mirror trajectory tracking but also facilitates force feedback mirroring. This study lays the foundation for future safety optimization of robot-assisted mirror rehabilitation training systems.