Combined kinematic and static analysis of an articulated lower limb traction device for a rehabilitation robotic system

This paper presents a design of an articulated lower limb traction device (ALLTD) with joint torque generators for a cable-driven parallel rehabilitation robotic system (CDPRRS). An earlier version of the ALLTD uses a rigid link to model the lower limbs of a patient. This paper extends this scenario to include articulations in the lower limbs and analyzes the resulting two-link mechanism. Due to the force-displacement coupled structure, the inverse and forward kinematics of the ALLTD model are analyzed in combination with the requirement for static force balance. Examples using the limb parameters of Chinese adults are provided to show the efficacy of our model. The workspaces and cable tensions of the model indicate that the ALLTD could satisfy the rehabilitation training needs of patients with various lengths of lower limbs.