Human Movement Training With a Cable Driven ARm EXoskeleton (CAREX)

Abstract

In recent years, the authors have proposed lightweight exoskeleton designs for upper arm rehabilitation using multi-stage cable-driven parallel mechanism. Previously, the authors have demonstrated via experiments that it is possible to apply "assist-as-needed" forces in all directions at the end-effector with such an exoskeleton acting on an anthropomorphic machine arm. A human-exoskeleton interface was also presented to show the feasibility of CAREX on human subjects. The goals of this paper are to 1) further address issues when CAREX is mounted on human subjects, e.g., generation of continuous cable tension trajectories 2) demonstrate the feasibility and effectiveness of CAREX on movement training of healthy human subjects and a stroke patient. In this research, CAREX is rigidly attached to an arm orthosis worn by human subjects. The cable routing points are optimized to achieve a relatively large "tensioned" static workspace. A new cable tension planner based on quadratic programming is used to generate continuous cable tension trajectory for smooth motion. Experiments were carried out on eight healthy subjects. The experimental results show that CAREX can help the subjects move closer to a prescribed circular path using the force fields generated by the exoskeleton. The subjects also adapt to the path shortly after training. CAREX was also evaluated on a stroke patient to test the feasibility of its use on patients with neural impairment. The results show that the patient was able to move closer to a prescribed straight line path with the "assist-as-needed" force field.

Design of a wearable cable-driven upper limb exoskeleton based on epicyclic gear trains structure

“…Some basic activities of daily living (ADLs) are difficult for elderly people to complete independently due to declines in motor function. Researchers are developing wearable exoskeleton robots to help the aged and disabled with completing ADLs [2][3][4][5][6][7][8][9]. Ideally, wearable exoskeleton should be ergonomical, light-weight, highly reliable and accurate, very stiff, and inexpensive [2].…”

“…The cable-driven mechanism allows the system to be quieter and have high accuracy and smooth transmissions which are necessary for wearable exoskeletons [6][7][8][9]. Mao et al [6,7] developed a cable driven arm exoskeleton (CAREX) for upper arm rehabilitation and Shao et al [8] designed a 3-DOF cable-driven upper arm exoskeleton.…”

“…Mao et al [6,7] developed a cable driven arm exoskeleton (CAREX) for upper arm rehabilitation and Shao et al [8] designed a 3-DOF cable-driven upper arm exoskeleton. However, the cable-driven parallel mechanism with flexible links is hard to be controlled.…”

Design and Optimization of a Hybrid-Driven Waist Rehabilitation Robot

“…However, there are some major drawbacks that exist, making the CDDRs often more difficult to design (e.g., it may be difficult to avoid cable interference) and more expensive to build and maintain when the number of cables and actuators is higher. On the other hand, the arrangement of cables should be more difficult in view of the recovery patient’s safety in this work [6,7]. Therefore, the number of cables can be reduced to a reasonable number.…”

Invariant spatial parametrization of human thoracohumeral kinematics: A feasibility study

“…These upper limb exoskeletons are required to work closely with the human anatomic joints. Hence, it is important to ensure user's safety and comfort [1]. Robust and reliable sensing of human upper limb kinematics is essential, not only for operation of these devices, but also in their functional evaluation.…”