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

Abstract

Abstract. BACKGROUND: Many countries, including Japan, Italy, and China are experiencing demographic shifts as their populations age. Some basic activities of daily living (ADLs) are difficult for elderly people to complete independently due to declines in motor function. OBJECTIVE: In this paper, a 6-DOF wearable cable-driven upper limb exoskeleton (CABexo) based on epicyclic gear trains structure is proposed. METHODS: The main structure of the exoskeleton system is composed of three epicyclic gear train sections. This new exoskeleton has a parallel mechanical structure to the traditional serial structure, but is stiffer and has a stronger carrying capacity. The traditional gear transmission structure is replaced with a cable transmission system, which is quieter, and has higher accuracy and smoother transmission. RESULTS AND CONCLUSIONS: The static workspace of the exoskeleton is large enough to meet the demand of assisting aged and disabled individuals in completing most of their activities of daily living (ADLs).

A review: A Comprehensive Review of Soft and Rigid Wearable Rehabilitation and Assistive Devices with a Focus on the Shoulder Joint

“…However, the position of glenohumeral joint rotation center changes with the upper arm movements. Important movements of the shoulder complex are flexion/ extension, abduction/adduction, and internal/external rotation, and in the most cases this complex is known in research as a limb with 3 Degrees of freedom (DOF)s [13] and in some other designs internal/external shoulder rotation is used less than other shoulder DOFs [22]. Due to constantly changing of the center of rotation of shoulder joint, it is necessary for some designs to be modelled as a 5 or 6 DOFs system, instead of modelling as a typical ball and socket joint [15].…”

“…The carpus joint is a formable joint that connects the forearm to the hand, and in some sources, the wrist joint has been interpreted as an oval joint [21]. In general, the carpus has been introduced as a member with two degrees of freedom in most studies [20,22,24]. In other words, when we consider that extension and flexion movements have one axis and also ulna and radius movements have one other axis, there will be a slight offset between these axes, the researchers measured it to be about 5 mm and it is shown in [13].…”

Mobile Mechatronic/Robotic Orthotic Devices to Assist–Rehabilitate Neuromotor Impairments in the Upper Limb: A Systematic and Synthetic Review

“…Regarding mobile devices, innovative systems are proposed in several articles (Yu and Rosen, 2010 ; Lenzi et al, 2011 ; Lin et al, 2013b ; Chen et al, 2014 ; Giberti et al, 2014 ; Tageldeen et al, 2016 ; Xiao et al, 2017 ). The respective approaches differ by their mechanisms to generate rotational DOF:…”

“…Electric : using gear rings (Chen et al, 2014 ) cable transmission systems (Xiao et al, 2017 ; Nycz et al, 2015 ); moving cylinders (Rocon et al, 2007 ; Lenzi et al, 2011 ; Wei et al, 2013 ).…”

“…Pneumatic : (Balasubramanian et al, 2008 ; Yu and Rosen, 2010 ; Chen et al, 2014 ; Dowling et al, 2014 ; Lee, 2014 ; Andrikopoulos et al, 2015 ; Nycz et al, 2016 ; Tu et al, 2017a , b ; Xiao et al, 2017 ) including pneumatic muscle actuators (Caldwell et al, 2007 ; Andrikopoulos et al, 2015 ).…”