scholarly journals Design and Preliminary Evaluation of a Wearable Passive Cam-Based Shoulder Exoskeleton

2021 ◽  
Author(s):  
Morteza Asgari ◽  
Elizabeth A. Phillips ◽  
Britt M. Dalton ◽  
Jennifer L. Rudl ◽  
Dustin L. Crouch
Keyword(s):  
Theoretical Model ◽  
Muscle Activity ◽  
Preliminary Evaluation ◽  
Mean Square ◽  
Proof Of Concept ◽  
Home Based ◽  
Shoulder Disability ◽  
The Moment ◽  
Shoulder Kinematics ◽  
Shoulder Elevation

Abstract BackgroundMechanically passive (i.e. spring-powered) exoskeletons may be a practical and affordable solution to meet a growing clinical need for continuous, home-based movement assistance. We designed, fabricated, and preliminarily evaluated the performance of a wearable, passive, cam-driven shoulder exoskeleton (WPCSE) prototype. MethodsThe novel feature of the WPCSE is a modular spring-cam-wheel module, which generates an assistive force that can be customized to compensate for any proportion of the shoulder elevation moment due to gravity. We performed a benchtop experiment to validate the mechanical output of the WPCSE against our theoretical model. We also conducted a pilot biomechanics study (four able-bodied subjects) to quantify the effect of a WPCSE prototype on muscle activity and shoulder kinematics during three one-degree-of-freedom shoulder movements. ResultsThe shoulder elevation moment produced by the spring-cam-wheel module alone closely matched the desired, theoretical moment. However, when measured from the full WPCSE prototype, the moment was lower (up to 30%) during positive shoulder elevation and higher (up to 120%) during negative shoulder elevation compared to the theoretical moment, due primarily to friction. Even so, a WPCSE prototype, compensating for about 25% of the shoulder elevation moment due to gravity, showed a trend of reducing root mean square (up to 50%) and peak (up to 53%) electromyogram magnitudes of several muscles crossing the shoulder during shoulder elevation and horizontal adduction/abduction movements. Subjects verbally reported that the WPCSE did not physically constrain them during the tested movements. ConclusionThe results provide proof-of-concept evidence that our WPCSE can potentially assist shoulder movements. The proposed WPCSE, once refined, could provide clinical and home-based rehabilitation for patients with shoulder disability.

scholarly journals Design and Performance Evaluation of a Wearable Passive Cable-driven Shoulder Exoskeleton

2020 ◽  
Author(s):  
Morteza Asgari ◽  
Elizabeth A. Phillips ◽  
Britt M. Dalton ◽  
Jennifer L. Rudl ◽  
Dustin L. Crouch
Keyword(s):  
Daily Living ◽  
Muscular Activity ◽  
Home Based ◽  
Biomechanical Evaluation ◽  
Shoulder Motion ◽  
Shoulder Disability ◽  
And Performance ◽  
The Moment ◽  
Shoulder Elevation ◽  
Mechanical Assistance

AbstractThe mechanical assistance provided by exoskeletons could potentially replace, assist, or rehabilitate upper extremity function in patients with mild to moderate shoulder disability to perform activities of daily living. While many exoskeletons are “active” (e.g. motorized), mechanically passive exoskeletons may be a more practical and affordable solution to meet a growing clinical need for continuous, home-based movement assistance. In the current study, we designed, fabricated, and evaluated the performance of a wearable, passive, cable-driven shoulder exoskeleton (WPCSE) prototype. An innovative feature of the WPCSE is a modular spring-cam-wheel system that can be custom designed to compensate for any proportion of the shoulder elevation moment due to gravity over a large range of shoulder motion. The force produced by the spring-cam-wheel system is transmitted over the superior aspect of the shoulder to an arm cuff through a Bowden cable. The results from mechanical evaluation revealed that the modular spring-cam-wheel system could successfully produce an assistive positive shoulder elevation moment that matched the desired, theoretical moment. However, when measured from the physical WPCSE prototype, the moment was lower (up to 30%) during positive shoulder elevation and higher (up to 120%) during negative shoulder elevation due primarily to friction. Even so, our biomechanical evaluation showed that the WPCSE prototype reduced the root mean square (up to 35%) and peak (up to 33%) muscular activity, as measured by electromyography, of several muscles crossing the shoulder during shoulder elevation and horizontal adduction/abduction movements. These preliminary results suggest that our WPCSE may be suitable for providing movement assistance to people with shoulder disability.

scholarly journals Back-Support Exoskeleton Control Strategy for Pulling Activities: Design and Preliminary Evaluation

Designs ◽  
2021 ◽  
Vol 5 (3) ◽  
pp. 39
Author(s):  
Maria Lazzaroni ◽  
Tommaso Poliero ◽  
Matteo Sposito ◽  
Stefano Toxiri ◽  
Darwin G. Caldwell ◽  
...  
Keyword(s):  
Control Strategy ◽  
Muscle Activity ◽  
Material Handling ◽  
Ease Of Use ◽  
Biomechanical Analysis ◽  
Perceived Support ◽  
Preliminary Evaluation ◽  
Subjective Measurements ◽  
Spinal Muscles ◽  
Forearm Muscle

The execution of manual material handling activities in the workplace exposes workers to large lumbar loads that increase the risk of musculoskeletal disorders and low back pain. In particular, the redesign of the workplace is making the execution of pulling activities more common, as an alternative to lifting and carrying tasks. The biomechanical analysis of the task revealed a substantial activation of the spinal muscles. This suggests that the user may benefit from the assistance of a back-support exoskeleton that reduces the spinal muscle activity and their contribution to lumbar compression. This work addresses this challenge by exploiting the versatility of an active back-support exoskeleton. A control strategy was specifically designed for assisting pulling that modulates the assistive torques using the forearm muscle activity. These torques are expected to adapt to the user’s assistance needs and the pulled object mass, as forearm muscle activity is considered an indicator of grip strength. We devised laboratory experiments to assess the feasibility and effectiveness of the proposed strategy. We found that, for the majority of the subjects, back muscle activity reductions were associated with the exoskeleton use. Furthermore, subjective measurements reveal advantages in terms of perceived support, comfort, ease of use, and intuitiveness.

scholarly journals Exploratory study of electromyographic behavior of the vastus medialis and vastus lateralis at neuromuscular fatigue onset

2014 ◽  
Vol 20 (2) ◽  
pp. 213-220 ◽  
Author(s):  
Cristiano Rocha da Silva ◽  
Danilo de Oliveira Silva ◽  
Deisi Ferrari ◽  
Rúben de Faria Negrão Filho ◽  
Neri Alves ◽  
...  
Keyword(s):  
Exploratory Study ◽  
Vastus Lateralis ◽  
Knee Extension ◽  
Neuromuscular Fatigue ◽  
Isometric Contractions ◽  
Median Frequency ◽  
Vastus Medialis ◽  
Mean Square ◽  
Electromyographic Signal ◽  
The Moment

This study aimed to determine and analyze the neuromuscular fatigue onset by median frequency (MDF) and the root mean square (RMS) behavior of an electromyographic signal (EMG). Eighteen healthy men with no prior knee problems initially performed three maximum voluntary isometric contractions (MVIC). After two days of MVIC test, participants performed a fatiguing protocol in which they performed submaximal knee-extension contractions at 20% and 70% MVIC held to exhaustion. The MDF and RMS values from the EMG signals were recorded from the vastus medialis (VM) and the vastus lateralis (VL). Analysis of the MDF and RMS behavior enabled identification of neuromuscular fatigue onset for VM and VL muscles in 20% and 70% loads. Alterations between the VM and VL in the neuromuscular fatigue onset, at 20% and 70% MVIC, were not significant. These findings suggest that the methodology proposal was capable of indicating minute differences sensible to alterations in the EMG signals, allowing identification of the moment when the MDF and the RMS showed significant changes in behavior. The methodology used was also a viable one for describing and identifying the neuromuscular fatigue onset by means of the analysis of EMG signals.

scholarly journals Muscle Activity during Dryland Swimming while Wearing a Triathlon Wetsuit

2018 ◽  
Vol 6 (1) ◽  
pp. 7 ◽  
Author(s):  
Ciro Agnelli ◽  
John A. Mercer
Keyword(s):  
Root Mean Square ◽  
Muscle Activity ◽  
Swimming Performance ◽  
Stroke Rate ◽  
Mean Square ◽  
Long Distance ◽  
Dry Land ◽  
Shoulder Muscle ◽  
Anterior Deltoid ◽  
Paired T Test

Background: Triathletes typically wear a wetsuit during the swim portion of an event, but it is not clear if muscle activity is influenced by wearing a wetsuit. Purpose: To investigate if shoulder muscle activity was influenced by wearing a full-sleeve wetsuit vs. no wetsuit during dryland swimming. Methods: Participants (n=10 males; 179.1±13.2 cm; 91.2±7.25 kg; 45.6±10.5 years) completed two dry land swimming conditions on a swim ergometer: No Wetsuit (NW) and with Wetsuit (W). Electromyography (EMG) of four upper extremity muscles was recorded (Noraxon telemetry EMG, 500 Hz) during each condition: Trapezius (TRAP), Triceps (TRI), Anterior Deltoid (AD) and Posterior Deltoid (PD). Each condition lasted 90 seconds with data collected during the last 60 seconds. Resistance setting was self-selected and remained constant for both conditions. Stroke rate was controlled at 60 strokes per minute by having participants match a metronome. Average (AVG) and Root Mean Square (RMS) EMG were calculated over 45 seconds and each were compared between conditions using a paired t-test (α=0.05) for each muscle. Results: PD and AD AVG and RMS EMG were each greater (on average 40.0% and 66.8% greater, respectively) during W vs. NW (p<0.05) while neither TRAP nor TRI AVG or RMS EMG were different between conditions (p>0.05). Conclusion: The greater PD and AD muscle activity while wearing a wetsuit might affect swimming performance and /or stroke technique on long distance event.

A NATIONAL DANISH PROOF OF CONCEPT ON FEASIBILITY AND SAFETY OF HOME -BASED INTENSIVE CHEMOTHERAPY IN PATIENTS WITH ACUTE MYELOID LEUKEMIA

2021 ◽  
pp. 106756
Author(s):  
Kristina Holmegaard Nørskov ◽  
Katrine Fridthjof ◽  
Peter Kampmann ◽  
Anne Dünweber ◽  
Christen Lykkegaard Andersen ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
Intensive Chemotherapy ◽  
Proof Of Concept ◽  
Home Based ◽  
Acute Myeloid

Trunk Posture Influences Neck Angle When Reading A Tablet Computer

2016 ◽  
Vol 60 (1) ◽  
pp. 942-942
Author(s):  
Kaitlin M. Gallagher ◽  
Ethan C. Douglas
Keyword(s):  
Muscle Activity ◽  
Erector Spinae ◽  
Flexion Angle ◽  
Neck Flexion ◽  
Handheld Computer ◽  
Extensor Muscles ◽  
Head Flexion ◽  
The Moment ◽  
Trunk Position ◽  
Gravitational Moment

In 2013, 64% of American households owned a handheld computer device (e-reader, tablet, smartphones, etc.). The presence of these devices has grown more quickly than our understanding of their effects on musculoskeletal disorders. Their use on a tabletop or a person’s lap causes increased head and neck flexion, as well as an inreased gravitational moment produced by the weight of the head (Straker et al., 2009, Young et al., 2012, Vasavada et al., 2015). A limitation to these studies is that they keep a standard trunk position throughout all tasks; however, people can also assume a semi-reclined position when reading a tablet. The purpose of this study was to determine the influence of a semi-reclined trunk position on neck and head flexion angle, and cervical erector spinae muscle activity. Nineteen participants (10 male, 9 female) read off of a tablet in four postures: with the tablet in their lap, on a tabletop, off of a standard computer monitor, and semi-reclined to an angle of 30 degrees from the vertical. Having the tablet on the lap ( M=16%MVC, SD=8%MVC) significantly increased muscle activity of the cervical erector spinae ( p=.0023) compared to reading off of a monitor or in the semi-reclined position (approximately 10%MVC). Neck and head flexion angles significantly increased ( p<.001) when reading the tablet off the lap (neck M=56.8o, SD=17.3o; head M=53.4o, SD=12.9o) versus the computer (neck M=6.4o, SD=6.4o; head M=8.2o, SD=7.4o), however, the head angle during semi-reclined reading stayed more vertical despite having the highest increase in neck flexion angle (neck M=71.6o, SD=14.0o; head M=19.7o, SD=9.2o). In the semi-reclined position, the gravitational moment of the head is second smallest for the four reading positions. In theory, this is desired as the moment that must be produced by the musculature and surround tissues would be less. The downside to this posture is that many of the neck extensor muscles may still not be in optimal force and moment production position. Many of the neck muscles that assist with extension originate from C5 to T5 and insert on C5 and above (Vasavada et al., 1998). At 30 degrees of neck flexion, the moment generating capability of the spenius and semispinalis muscles are decreased compared to when at a neutral position and fascicle length of splenius cervicis, capitis, and semispinalis capitis muscles experience changes of more than 70% of optimal length (Vasavada et al., 1998). While many of the extensor muscles only show moment arms that vary by 1 cm or less, for some there can be about a 2-3 cm changes as one goes from a flexed to extended neck posture (Vasavada et al., 1998). These combined changes mean that the force producing capabilities of the neck extensor muscles may be compromised a semi-reclined position. Future studies should report torso angle to properly analyze biomechanical risk factors during handheld computer use and compare results between studies.

scholarly journals Respiratory muscle activity after spontaneous, neostigmine- or sugammadex-enhanced recovery of neuromuscular blockade: a double blind prospective randomized controlled trial

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Tom Schepens ◽  
Koen Janssens ◽  
Sabine Maes ◽  
Davina Wildemeersch ◽  
Jurryt Vellinga ◽  
...  
Keyword(s):  
Neuromuscular Blockade ◽  
Muscle Activity ◽  
Spontaneous Breathing ◽  
Respiratory Muscle ◽  
Secondary Outcome ◽  
Emg Activity ◽  
Double Blind ◽  
Randomized Controlled ◽  
The Moment ◽  
Respiratory Muscle Activity

Abstract Background The use of neostigmine after neuromuscular blockade (NMB) has been associated with postoperative respiratory complications. In previous studies, we found lower diaphragmatic activity after neostigmine reversal of NMB, compared to sugammadex. It is still unclear whether the adequate use of neostigmine guarantees normal respiratory muscle function after NMB. In this study, we wanted to assess the effect of commonly used degrees of NMB and their possible reversal strategies on respiratory muscle activity after the return of normal neuromuscular transmission. Methods This is a randomized, controlled, parallel-group, single-centre, double-blind study in patients scheduled for intracranial surgery at a tertiary academic hospital in Belgium. All participants received target controlled propofol/remifentanil anesthesia and were randomized into one of five groups, receiving either a shallow NMB with no reversal (shallow/saline), a shallow NMB with sugammadex reversal (shallow/sugammadex), a moderate NMB with neostigmine reversal (moderate/neostigmine), a moderate NMB with sugammadex reversal (moderate/sugammadex), or a deep NMB with sugammadex reversal (deep/sugammadex). Primary and secondary outcome parameters were diaphragm and intercostal electromyographic (EMG) activity at the moment of resumed spontaneous breathing activity, defined as a maximal interval of 10 min after the first spontaneous breath. Results For the five groups, a total of 55 patients could be included in the final analysis. Median time of spontaneous breathing analyzed was 5 min (IQR 3–9.5 min). Both the moderate/sugammadex and the moderate/neostigmine groups had lower levels of diaphragm EMG compared to the shallow/sugammadex group. The moderate/neostigmine group had lower levels of intercostal EMG activity compared to the shallow/saline group. Conclusions In this study, the depth of neuromuscular blockade and type of reversal strategy impacts respiratory muscle activity at the moment of resumed spontaneous breathing and recovery of neuromuscular blockade. Both groups that received moderate NMB had lower levels of diaphragm EMG, compared to the shallow NMB group with sugammadex reversal. Compared to the shallow NMB group with no reversal, the moderate NMB with neostigmine reversal group had lower intercostal EMG activity. Trial registration Clinicaltrials.gov NCT01962298 on October 9, 2013 and EudraCT 2013–001926-25 on October 10, 2013.

Convergence analysis of Bessel beamformer and its comparison with LMS in adaptive array system

2015 ◽  
Vol 34 (3) ◽  
pp. 952-961 ◽  
Author(s):  
M. Yasin ◽  
Pervez Akhtar
Keyword(s):  
Theoretical Model ◽  
Convergence Analysis ◽  
Digital Signal Processor ◽  
Wiener Filter ◽  
Digital Signal ◽  
Lms Algorithm ◽  
Mean Square ◽  
Least Mean Square ◽  
Content Type ◽  
Convergence Performance

Purpose – The purpose of this paper is to analyze the convergence performance of Bessel beamformer, based on the design steps of least mean square (LMS) algorithm, can be named as Bessel LMS (BLMS) algorithm. Its performance is compared in adaptive environment with LMS in terms of two important performance parameters, namely; convergence and mean square error. The proposed BLMS algorithm is implemented on digital signal processor along with antenna array to make it smart in wireless sensor networks. Design/methodology/approach – Convergence analysis is theoretically developed and verified through MatLab Software. Findings – Theoretical model is verified through simulation and its results are shown in the provided table. Originality/value – The theoretical model can obtain validation from well-known result of Wiener filter theory through principle of orthogonality.

A Framework Supporting Life-Cycle Guidance for Fabricating Micro Components by Compression Moulding

2010 ◽  
Author(s):  
P. J. Farrugia ◽  
P. Vella ◽  
M. Mifsud
Keyword(s):  
Design Methodology ◽  
Typical Case ◽  
Economic Feasibility ◽  
Preliminary Evaluation ◽  
Proof Of Concept ◽  
Compression Moulding ◽  
Micro Manufacturing ◽  
Computer Based ◽  
Design And Manufacture ◽  
Future Work

Micro-products and components are rapidly increasing in a range of sectors. This demand requires industrial technologies capable of mass producing polymer micro products at a reasonable price. These two requirements are satisfied by the use of replication technologies such as micro compression moulding (μCM). A literature review that we conducted revealed that there is indeed little if any work explicitly related to the domain of micro compression moulding. In addition, a design methodology in micro manufacturing is still in its infancy and that there is a shortage of relevant DFX guidelines. Thus, this research aims at developing a framework for a computer-based tool whereby micro-product stakeholders are guided to select the correct mould features, material, machine and process parameters for fabricating components via micro compression moulding. The paper presents a framework developed to meet this goal. A proof-of-concept tool has also been implemented based on this framework. This tool was evaluated by typical case studies and also presented to a number of experts in the field. Preliminary evaluation results provide a degree of evidence that technology based on the framework contributes a step towards providing guidance for the design and manufacture of mould tools for fabricating μ-components by compression moulding. Another contribution of this paper is the preliminary fabrication platform using μCM. Future work is however required mainly to assess the economic feasibility of the fabrication platform, to address the limitations of the implemented tool, and to assess its effectiveness in practice.

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