Optimal Design of a 3-DOF Cable-Driven Upper Arm Exoskeleton

Abstract

With outstanding advantages, such as large workspace, flexibility, and lightweight and low inertia, cable-driven parallel manipulator shows great potential for application as the exoskeleton rehabilitation robot. However, the optimal design is still a challenging problem to be solved. In this paper, the optimal design of a 3-DOF (3-degree-of-freedom) cable-driven upper arm exoskeleton is accomplished considering the force exerted on the arm. After analysis of the working conditions, two promising configurations of the cable-driven upper arm exoskeleton are put forward and design parameters are simplified. Then, candidate ranges of two angle parameters are determined with the proposed main workspace requirement. Further, global force indices are defined to evaluate the force applied to the arm by the exoskeleton, in order to enhance the system safety and comfort. Finally, the optimal design of each configuration is obtained with proposed force indices. In addition, atlases and charts given in this paper well illustrate trends of workspace and force with different values of design parameters.

A Review on Design of Upper Limb Exoskeletons

“…Shao et al [69] presented an optimal design of three degrees of freedom cable-driven upper-arm exoskeleton. To achieve an optimal design challenge, a study was conducted by keeping in mind the major limitation of modeling the cable-driven mechanisms and the way it impact the rehabilitation performance.…”

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

“…7 can be obtained using Eq. (8), and the static workspace of the exoskeleton is reasonably large in order to meet the demands of assisting the aged and disabled to complete ADLs.…”

“…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.…”