Robust controls for upper limb exoskeleton, real-time results

Abstract

This article shows the development of an exoskeleton for human joint. The exoskeleton proposed was developed for rehabilitating individuals who have suffered injuries at their shoulders, by rehabilitation exercises. The exoskeleton has special characteristics to deal with the 5 degrees of freedom of the human shoulder. The dynamic model results in the following form: € q = f (q, _ q) + b(q)u, where q, u, f (q, _ q) and b(q) are state's vector, torque's vector, a matrix function and a vector function, respectively. Therefore, we applied four different control laws, among which stand two robust controls (adaptive sliding modes and proportional-derivative with adaptive gravity compensation). The adaptive controller properties allow the exoskeleton to adapt to different humans with different parameters such as size, length, weight and so on that, in mathematical terms, is represented as a mechanical system with uncertainties.

Artificial Intelligence-Based Wearable Robotic Exoskeletons for Upper Limb Rehabilitation: A Review

“…Various developments [ 24 , 25 , 26 , 31 , 42 ] do not specifically refer to the implemented operation modes; however, it was deduced that an active control was implemented. In other works [ 39 , 40 , 43 , 45 , 47 , 51 ], the robotic exoskeleton has provided complete rehabilitation assistance through active control.…”

“…In detail, [ 31 ] stated that an important objective was the matching between the exoskeleton and the human movements. The five DoFs were arranged as follows: (i) three DoFs for the glenohumeral joint, and (ii) two DoFs for the scapulothoracic joint.…”

“…In-depth studies have shown some devices that can assist both the rehabilitation process and the measurement of users’ physiological parameters in the rehabilitation process, making this approach more comprehensive [ 31 ]. Specifically in [ 37 ], the proposed device was designed to help stroke survivors improve their motor function without being equipped as a neurorehabilitation system.…”

“…From the mechanical standpoint, the design of exoskeletons must be oriented towards more flexible, adaptable, wearable, and lightweight structures, as some of the devices do not yet fully meet these criteria [ 23 , 27 , 34 , 45 , 48 , 49 , 52 , 53 ]. As for the materials used for the functional structures of the devices, the use of 3D printed plastics is recommended due to rapid prototyping for user comfort, such as those evidenced in [ 22 , 26 , 29 , 33 , 36 , 42 , 46 , 48 ], or in a mix with low weight metal alloys [ 24 , 31 , 39 , 41 , 45 , 47 , 55 ]. The incorporation of more materials approved for medical use should be actively sought, such as [ 42 ].…”

Hybrid Approach of Finite Element Method, Kigring Metamodel, and Multiobjective Genetic Algorithm for Computational Optimization of a Flexure Elbow Joint for Upper‐Limb Assistive Device

“…In the state of art of rehabilitation process, assist robots and rehabilitation devices have been designed and commercialized. Robotic devices for upper-limb rehabilitation were proposed for shoulder exercises [1]. Mechanical structures and control strategies for exoskeletons for upper-limb exoskeletons were reviewed [2].…”