Dynamic Analysis and Preliminary Evaluation of a Spring-Loaded Upper Limb Exoskeleton for Resistance Training with Overload Prevention

2012 ◽  
Vol 29 (1) ◽  
pp. 35-44 ◽  
Author(s):  
T.-M. Wu ◽  
D.-Z. Chen

ABSTRACTResistance training has been shown to be effective for developing musculoskeletal strength and is recommended by many major health organizations, such as the American College of Sports Medicine and the American Heart Association. This form of training is available for most populations, including adolescents, healthy adults, the elderly, and the clinical population. Resistance training equipment design relies heavily on the analysis of human movement. Dynamic models of human movement help researchers identify key forces, movements, and movement patterns that should be measured. An at-home resistance training upper limb exoskeleton has been designed with a three-degree-of-freedom shoulder joint and a one-degree-of-freedom elbow joint to allow movement of the upper limb at single and multiple joints in different planes. The exoskeleton can continuously increase the resistance as the spring length changes to train more muscle groups and to reduce the potential risk of muscle injury to the upper limb by free weights and training equipment. The objectives of this research were to develop a dynamic model of the spring-loaded upper limb exoskeleton and to evaluate this model by adopting an appropriate motion analysis system to verify our hypotheses and to determine the optimal configuration of a spring-loaded upper limb exoskeleton for further verification studies.

2020 ◽  
Author(s):  
Chang He ◽  
Cai-Hua Xiong ◽  
Ze-Jian Chen ◽  
Wei Fan ◽  
Xiao-Lin Huang

Abstract Background: Upper limb exoskeletons have drawn significant attention in neurorehabilitation because of anthropomorphic mechanical structure analogous to human anatomy. Whereas, the training movements are typically underorganized because most exoskeletons only control the movement of the hand in space, without considering rehabilitation of joint motion, particularly inter-joint postural synergy. The purposes of this study were to explore the application of a postural synergy-based exoskeleton (Armule) reproducing natural human movements for robot-assisted neurorehabilitation and to preliminarily assess its effect on patients' upper limb motor control after stroke. Methods: We developed a novel upper limb exoskeleton based on the concept of postural synergy, which provided five degrees of freedom (DOF) , natural human movements of the upper limb. Eight participants with hemiplegia due to a first-ever, unilateral stroke were recruited and included. They participated in exoskeleton therapy sessions 45 minutes/day, 5 days/week for 4 weeks, with passive/active training under anthropomorphic trajectories and postures. The primary outcome was the Fugl-Meyer Assessment for Upper Extremities (FMA-UE). The secondary outcomes were the Action Research Arm Test(ARAT), modified Barthel Index (mBI) , and exoskeleton kinematic as well as interaction force metrics: motion smoothness in the joint space, postural synergy error, interaction force smoothness, and the intent response rate. Results: After the 4-weeks intervention, all subjects showed significant improvements in the following clinical measures: the FMA-UE ( p =0.02), the ARAT ( p =0.003), and the mBI score ( p <0.001). Besides, all subjects showed significant improvements in motion smoothness ( p =0.004), postural synergy error ( p =0.014), interaction force smoothness ( p =0.004), and the intent response rate ( p =0.008). Conclusions: The subjects were well adapted to our device that assisted in completing functional movements with natural human movement characteristics. The results of the preliminary clinical intervention indicate that the Armule exoskeleton improves individuals’ motor control and activities of daily living (ADL) function after stroke, which might be associated with kinematic and interaction force optimization and postural synergy modification during functional tasks. Clinical trial registration: ChiCTR, ChiCTR1900026656; Date of registration: October 17, 2019. http://www.chictr.org.cn/showproj.aspx?proj=44420


Robotica ◽  
2019 ◽  
Vol 37 (12) ◽  
pp. 2073-2086 ◽  
Author(s):  
Amin Zeiaee ◽  
Rana Soltani-Zarrin ◽  
Reza Langari ◽  
Reza Tafreshi

SummaryThis paper studies the problem of optimizing the kinematic structure of an eight degree-of-freedom upper-limb rehabilitation exoskeleton. The objective of optimization is achieving minimum volume and maximum dexterity in the workspace of daily activities specified by a set of upper-arm configurations. To formulate the problem, a new index is proposed for effective characterization of kinematic dexterity for wearable robots. Additionally, a set of constraints are defined to ensure that the optimal design can cover the desired workspace of the exoskeleton, while singular configurations and physical interferences are avoided. The formulated multi-objective optimization problem is solved using an evolutionary algorithm (Non-dominated Sorting Genetic Algorithm II) and the weighted sum approach. Among the resulted optimal points, the point with least sensitivity with respect to the variations of design variables is chosen as the final design.


2015 ◽  
Vol 811 ◽  
pp. 305-310
Author(s):  
Tadeusz Mikolajczyk ◽  
Adrian Olaru ◽  
Pawel Walkowiak

The effectiveness of rehabilitation is closely linked with suitably chosen therapy. The treatment can be performed only by specialized personnel or through the use of automated devices. One of the potential solution of this problem is exoskeleton. It is the kind of suit that allows the user assumed to support or even replace the human motor. The paper presents a proposal of the exoskeleton with 1 degree of freedom providing upper extremity rehabilitation in the elbow with the master-slave program. Control is via stepper motor which ensures high accuracy in the implementation of programmed movements.


Sign in / Sign up

Export Citation Format

Share Document