Pilot Study of a Powered Exoskeleton for Upper Limb Rehabilitation Based on the Wheelchair

Abstract

To help hemiplegic patients with stroke to restore impaired or lost upper extremity functionalities efficiently, the design of upper limb rehabilitation robotics which can substitute human practice becomes more important. The aim of this work is to propose a powered exoskeleton for upper limb rehabilitation based on a wheelchair in order to increase the frequency of training and reduce the preparing time per training. This paper firstly analyzes the range of motion (ROM) of the flexion/extension, adduction/abduction, and internal/external of the shoulder joint, the flexion/extension of the elbow joint, the pronation/supination of the forearm, the flexion/extension and ulnar/radial of the wrist joint by measuring the normal people who are sitting on a wheelchair. Then, a six-degree-of-freedom exoskeleton based on a wheelchair is designed according to the defined range of motion. The kinematics model and workspace are analyzed to understand the position of the exoskeleton. In the end, the test of ROM of each joint has been done. The maximum error of measured and desired shoulder flexion and extension joint angle is 14.98%. The maximum error of measured and desired elbow flexion and extension joint angle is 14.56%. It is acceptable for rehabilitation training. Meanwhile, the movement of drinking water can be realized in accordance with the range of motion. It demonstrates that the proposed upper limb exoskeleton can also assist people with upper limb disorder to deal with activities of daily living. The feasibility of the proposed powered exoskeleton for upper limb rehabilitation training and function compensating based on a wheelchair is proved.

An innovative equivalent kinematic model of the human upper limb to improve the trajectory planning of exoskeleton rehabilitation robots

“…Misalignment compensation for full human-exoskeleton kinematic compatibility will reduce the effect of rehabilitation training, limit arm movement, and cause discomfort or secondary injury (Lo and Xie, 2012;Rocon et al, 2007;Schiele and Helm, 2006;Cao et al, 2020). There are three main methods of misalignment compensation, including manual alignment, compliant elements, and adding kinematic redundancy (Näf et al, 2019). Different misalignment compensation methods have different effects, so the effects need to be evaluated.…”

“…In order to help patients with hemiplegia or spinal cord injury to restore impaired or lost upper limb functionalities efficiently, Meng et al (2019) designed an upper limb exoskeleton robot based on a wheelchair, which not only transfers the weight of the affected limb and exoskeleton to the wheelchair, but also integrates rehabilitation training and assisting in ADL functions (Meng et al, 2019). The prototype of an upper limb exoskeleton robot based on a wheelchair has 3 active DOF, and its primary movements are internal/external rotation and flexion/extension of the shoulder joint and flexion/extension of the elbow joint.…”

Design and evaluation of a novel upper limb rehabilitation robot with space training based on an end effector

“…The ROM required for ADL by 95 % of the population is derived for the maximum values of the related work in (Namdari et al, 2012;Magermans et al, 2005;Gates et al, 2016) and translated to the ISB system, as shown in Table 4.…”

“…This paper performs a series of smooth pursuit movement experiments with a healthy male subject, who is 26 years old, to evaluate the ability of the proposed mechanism. Smooth pursuit movement is the movement of the tester's arm driven by the robot (Meng et al, 2019). These test motions include the shoulder flexion/extension and adduction/abduction and the elbow flexion/extension.…”

“…The exoskeleton-type upper limb rehabilitation robot has a kinematic structure similar to that of the human upper limb, and it generates driving force on each joint of the patient's upper limb to drive limb rehabilitation training, such as CADEN-7 (Perry et al, 2007), Harmony (Kim and Deshpande, 2017), ARMin III (Nef et al, 2009), Co-EXos (Zhang et al, 2019), Armeo Power (Jarrase et al, 2015), and LIMPACTA (Otten et al, 2015). Compared with the end-effector-based robot, the exoskeleton robot can drive the patient's limbs to perform three-dimensional rehabilitation training, especially the large-ROM flexion/extension training of the human shoulder.…”