Safety Evaluation and Experimental Study of a New Bionic Muscle Cable-Driven Lower Limb Rehabilitation Robot

Abstract

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.

Human Factor Engineering Research for Rehabilitation Robots: A Systematic Review

“…The safety evaluation of rehabilitation robots aims to achieve safe interaction between patients and rehabilitation robots and currently focuses on the safety performance of the rehabilitation robot system itself during human-robot interaction. Wang et al [ 36 ] defined safety performance factors, such as rope tension, system stiffness, fluctuation of motion velocity of slider B1 in the rigid motion support chain, and motion velocity of the lower limb traction point by mechanical analysis of the bionic muscle cable-driven lower limb rehabilitation robot (BM-CDLR) and gave a structural safety evaluation index and used the BM-CDLR safety evaluation index by combining the velocity influence function.…”

Motion Planning for a Cable-Driven Lower Limb Rehabilitation Robot with Movable Distal Anchor Points

“…It has the advantages of good man-machine compatibility, adjustable stiffness, and diverse training forms. For example, STRING-MAN [1,2], hybrid-driven waist rehabilitation robot [3,4], cable-driven upper limb rehabilitation robot [5,6], and bionic muscle cable-driven lower limb rehabilitation robot [7,8]. The moving platform of a cabledriven rehabilitation robot should move accurately along a specific trajectory according to the rehabilitation needs, it has certain requirements for the stability and safety of the robot simultaneously.…”

Research on mechanical optimization methods of cable-driven lower limb rehabilitation robot

“…In order to improve the kinematic characteristics of cable-driven parallel robots, researchers have done a lot of work. For example, the stability [19,21,22] and safety [23] of cable-driven rehabilitation robots were analyzed based on the characteristics of cable tension and system stiffness. Considering the workspace, cables tensions, cables sagging, compactness, singularity, and safety of the cable-driven parallel robot (CDPR), a dimensional synthesis optimization method [24] was proposed.…”

“…In order to evaluate the dynamical stability and safety of CDLR, the cable tension factors [5,6,23,29] were defined to measure the ability of the system to resist external interference in different directions based on the distribution of cable tension. Due to the evaluation of the CDPR's performances cannot be performed using the performance indexes for parallel robots with rigid links, an improved wrench exertion capability index was proposed to evaluate the maximum tension force that cable can exert along a direction of interest.…”

“…However, due to the hysteresis of pneumatic muscles, the control of the mechanism is still facing a great challenge in practical application. In order to prevent the pseudo-drag phenomenon of cables and to ensure the safety of patients, the minimum tension force of cables must be limited [23,33]. Therefore, in actual applications, the calibrated sensors and the data collected by them must be used to guarantee the existence of the minimum tension force in cables in rehabilitation training [33].…”