Movements Of Upper Arm Research Articles

Design and Verification of Lockable Upper-Limb Exoskeleton Based on Jamming and Engagement Mechanisms

This letter presents a lockable upper-limb exoskeleton to reduce the physical fatigue of laborers/surgeons operating with upper limbs maintaining fixed posture for long time. A novel structure design integrating the jamming and engagement mechanisms that can provide locking of flexion and adduction movements of upper arm without affecting the motion space is proposed. An air-pressure waist bag with a voice control interface is developed, giving good portability and user convenience to the exoskeleton. The system is validated in experiments, indicating a locking torque as large as 6 Nm with 3.5 bar air pressure. Locking and unlocking settling times of the jamming mechanism are 0.09 s and 0.10 s, meaning nearly no delay can be felt by users for the switching. Moreover, surface electromyography (EMG) signal tests demonstrate that the proposed exoskeleton can significantly reduce muscle activation of randomly selected subjects by 25%--73%. Compared with commercially-available passive exoskeletons, proposed system has a lower weight, much larger and adjustable locking torque owing to the specially designed jamming mechanism. The exoskeleton presents good compliance, great flexibility, and hands free human-machine interface, showing good potential for physical fatigue reduction of laborers/surgeons over long-term operations.

Wearable sensors for 3D upper limb motion modeling and ubiquitous estimation

Human motion capture technologies are widely used in interactive game and learning, animation, film special effects, health care, and navigation. Because of the agility, upper limb motion estimation is the most difficult problem in human motion capture. Traditional methods always assume that the movements of upper arm and forearm are independent and then estimate their movements separately; therefore, the estimated motion are always with serious distortion. In this paper, we propose a novel ubiquitous upper limb motion estimation method using wearable microsensors, which concentrates on modeling the relationship of the movements between upper arm and forearm. Exploration of the skeleton structure as a link structure with 5 degrees of freedom is firstly proposed to model human upper limb motion. After that, parameters are defined according to Denavit-Hartenberg convention, forward kinematic equations of upper limb are derived, and an unscented Kalman filter is invoked to estimate the defined parameters. The experimental results have shown the feasibility and effectiveness of the proposed upper limb motion capture and analysis algorithm.

Postures and Movements in the Most Common Tasks of Power Line Workers

The repair and maintenance of electrical power lines involves awkward postures, which are known risk factors for developing musculoskeletal disorders. The aim of the present study was to quantify postures and movements of upper arm, head, upper back and neck in the main tasks performed by line workers. Posture of twelve right-handed line workers was recorded by inclinometry and presented as percentiles of angular and angular velocity distributions. All tasks involved considerable upper-arm elevation, ranging from 73° to 115° for the 90th percentile. Upper-arm elevation showed significant differences between tasks, but no consistent differences between right and left sides. Regarding velocity, the right arm presented higher levels than the left arm. All tasks required significant extension of head, upper back and neck, ranging from 7° to 67° for head (10th percentile). All tasks, except the one performed with a continuous extension, also involved pronounced flexion, ranging from 33° to 60° for the head (90th percentile). Work which required highly elevated arms also required significant head extension (r(2)=0.56). Awkward postures of upper arms, head, upper back and neck were identified by inclinometry, demonstrating the need for preventative interventions to reduce musculoskeletal disorders among line workers.

Electromyographic Study of Selected Muscles Involved in Movements of Upper Arm at Scapulohumeral Joint

Abstract This article presents an investigation, by means of electromyography, of the functions of the biceps brachii, the deltoideus, the latissimus dorsi, the pectoralis major, the serratus anterior, the cleido mastoideus, the teres major, the trapezius, and the triceps brachii (long head) in movements of the upper arm and the shoulder girdle at scapulo-humeral, acromioclavicular, and sternoclavicular joints. The procedure for collecting the data was established on the basis of records taken on twelve subjects; and the findings that are reported were based on 20 complete sets taken on five subjects.