Dynamic Movement Primitives Modulation-Based Compliance Control for a New Sitting/Lying Lower Limb Rehabilitation Robot

Abstract

Compliant physical human-robot interaction (pHRI), as well as the accuracy and robustness of trajectory tracking, are crucial for rehabilitation robots. In this paper, a new sitting/lying lower limb rehabilitation robot, SUT-SLLRR, has been designed for patients with lower extremity motor dysfunction. A dynamic movement primitives modulation-based compliance control strategy (DMPM-CCS) has been proposed for the SUT-SLLRR. The high-level trajectory planner consists of the trajectory generator based on dynamic movement primitives (DMPs), acceleration layer modulation generator, and velocity layer modulation generator, which can reshape the reference trajectory to generate desired trajectory within a constrained joint space through pHRI. Besides, the linear active disturbance rejection controller (LADRC) is adopted as the low-level position controller to ensure that each joint can accurately and robustness track the desired trajectory under internal and external disturbances. Simulation and experimental results indicate that the proposed strategy can provide the compliant pHRI within the constrained joint space and ensure the accuracy and robustness of trajectory tracking.

Keywords

• Sitting/lying lower limb rehabilitation robot
• compliance control
• physical human-robot interaction
• dynamic movement primitives
• linear active disturbance rejection control