Exoskeletal wheelchair operational assistance robot for C5 level cervical cord injury

Abstract

Cervical Cord Injury(CCI) causes a upper limb dysfunction. In an individual with C5-level CCI, which is the most frequent of all eight types of CCI, flexion force can be exerted by the biceps brachii, while extension force cannot be exerted by the paralyzed triceps brachii. Without the ability of the triceps brachii to exert this force, individuals with a C5-level CCI cannot operate a wheelchair along a carpet or sloping road. In this study, we developed an exoskeletal wheelchair operational assistance robot. We first developed a upper limb motion assistance robot. We then analyzed the difference between the wheelchair operations of a healthy person and a C5-level CCI. We designed a control model that included a user and a wheelchair. The wearer's arm was modeled as a two-link manipulator, and the extension force and hand position were estimated using the equation of motion. The estimated extension force was compared with the driving force required to operate a wheelchair with the target velocity defined at the time of flexion of an arm. We then applied the proposed method via an exoskeletal robot. The effectiveness of the proposed method is demonstrated by the experiment of wheelchair operation with C5-level CCI.

Keywords

• exoskeletal robot
• wheelchair operation
• cervical cord injury
• upper limb
• muscle and skeleton
• human-robot interaction
• mechatronics