Safety is a significant evaluation index of rehabilitation medical devices and a significant precondition for practical application. However, the safety evaluation of cable-driven rehabilitation robots has not been reported, so this work aims to study the safety evaluation methods and evaluation index of cable-driven rehabilitation robots. A bionic muscle cable (BM cable) is proposed to construct a bionic muscle cable-driven lower limb rehabilitation robot (BM-CDLR). The working principle of the BM-CDLR is introduced. The safety performance factors are defined based on the mechanical analysis of the BM-CDLR. The structural safety evaluation index and the use safety evaluation index of the BM-CDLR are given by comprehensively considering the safety performance factors and a proposed speed influence function. The effect of the structural parameters of the elastic elements in the BM cable on the safety performance factors and safety of the BM-CDLR is analyzed and verified by numerical simulations and experimental studies. The results provide the basis for further study of the compliance control strategy and experiments of the human-machine interaction of the BM-CDLR.

During rehabilitative training, a 3-DOF wire-driven parallel robot driven was designed to coordinate and control the trainer pelvis movement. Based on the force balance equation of the end-effector, the stiffness problem about the robot system was analyzed and one kind of force/position parallel control strategy was proposed that the position loop would realize the end-effector motion trajectory, and the force loop would control the wire tension. The experimental results have shown that the robot systematic stiffness is related with the wire tension and can be changed to realize the compliance control of the robot system by adjusting the wire tension.