Utafiti huu unachunguza design na feasibility ya prototype wearable Arm Swing Facilitator Device (ASFD) iliyotengenezwa kuanzisha arm swing wakati wa gait training kwa kuzalisha shoulder flexion-extension motion. System ina 260 W brushless motor iliyowekwa mgongoni, two-stage belt-pulley transmission yenye total ratio ya 12:1, Bowden-cable transmission na double-parallelogram linkage mechanism inayotumika kutoa wide shoulder workspace. Katika static-load test, 15,09 N·m ilipatikana; katika dynamic test, maximum output torque ya 10,74 N·m ilipatikana kwa total test mass ya 3,417 kg na condition ya 1,1 Hz. Katika feasibility experiment iliyofanywa na healthy male participants watano wakiwa wamesimama na arms passive, device iliweza kutengeneza arm swing katika frequencies za 0,8, 1,0 na 1,2 Hz. Kwa upande mwingine, study haikutest rehabilitation effectiveness wakati wa walking au katika neurological/clinical patient group.

Main engineering objective ya research ni kuhamisha actuator weight mbali na user arm wakati wa kuzalisha cyclic arm movement inayolingana na walking rhythm ya karibu 1 Hz, kuhifadhi other shoulder degrees of freedom kadiri iwezekanavyo, na kutoa assistance karibu na magnitude ya physiological shoulder torque. Design target iliwekwa karibu 12 N·m. Kwa kuwa nominal motor torque ni karibu 1,02 N·m, total 12:1 torque-amplification ratio iliundwa kwa transmission stages mbili za 3:1 na 4:1.

Transmission experiments zilionyesha kwamba total mechanical efficiency hubadilika kulingana na movement frequency. Total efficiency ilipimwa kuwa %82,9 katika 0,8 Hz, %86,5 katika 1,0 Hz na %90,1 katika 1,2 Hz. Katika conditions zilezile, total mechanical loss ilikuwa %17,1, %13,5 na %9,9 mtawalia. Watafiti wanahusisha efficiency increase katika higher frequency na improved belt engagement na reduced slipping.

Kwa shoulder workspace, device ilihifadhi sehemu kubwa ya flexion/extension na abduction/adduction motions; lakini rotation ilikuwa limited zaidi. Maximum abduction iliyopimwa kwa ASFD wakati wa human experiment iliripotiwa kuwa 129,76°, flexion 125,5°, extension 36,93°, external rotation 24,58° na internal rotation 56,21°. Katika discussion ya study, external-rotation limitation ilionekana acceptable kwa targeted arm-swing task ya device.

Kwa mtazamo wa Uturuki: Research haikufanywa kwenye clinical applications, rehabilitation centers au patient populations nchini Uturuki. Kwa hiyo, rehabilitation success ya device au suitability yake kwa clinical use nchini Uturuki haiwezi kutolewa kutoka study hii. Hata hivyo, study inatoa detailed prototype example kwa research teams zinazofanya kazi katika shoulder exoskeletons, rehabilitation robotics, wearable mechanisms na human-robot interaction kuhusu jinsi mechanical design, torque sizing, workspace na early human feasibility assessment zinaweza kufanywa pamoja. Kwa transition kwenda clinical use, separate validations zinahitajika kwa testing wakati wa walking, bilateral structure, target patient groups, long-term use na larger sample.

Main question ya research ni nini?

Main question ni kama wearable device inayozalisha programmable shoulder flexion-extension motion katika speeds karibu na natural walking frequencies, huku ikiweka other shoulder motions free kadiri iwezekanavyo, ni technically feasible.

Watafiti wanaanza kutoka problem kwamba users ambao hawawezi kuanzisha arms vya kutosha au wana difficulty kubadilisha arm swing wanaweza kuhitaji stronger mechanical guidance kuliko tactile feedback pekee. Hata hivyo, prototype hii haikutengenezwa kama direct treatment device, bali kama research tool ya kubaini torque na motion characteristics zinazohitajika kuunda arm swing.

ASFD ilitengenezwa kwa design requirements zipi?

Study imefafanua five main design requirements kwa arm swing:

1. Actuators kuwekwa mgongoni ili zisiongeze load kwenye arm.
2. Only shoulder flexion/extension kuendeshwa actively.
3. Wide passive freedom kutolewa katika other shoulder motions kama abduction/adduction na internal/external rotation.
4. Approximately sinusoidal motion kuweza kutengenezwa katika normal walking-frequency range ya karibu 0,8–1,1 Hz.
5. Sufficient torque kutengenezwa kwa shoulder motion.

Prototype inaunganisha rigid-link mechanism na remote actuation kupitia Bowden cable ili kutimiza requirements hizi. Rigid links hudhibiti endpoint geometry huku Bowden cable ikiruhusu motor kubaki mgongoni.

Torque inayohitajika kwa arm swing ilikadiriwaje?

Watafiti walimodeli upper arm na forearm kama two-link planar mechanism. Shoulder na elbow zilichukuliwa kama one-degree-of-freedom revolute joints; joint viscosity na stiffness zilipuuzwa kwa approximate torque estimation.

Standard Newton–Euler dynamic relation ilitumika:

\[ \tau = H(\theta)\ddot{\theta}+V(\theta,\dot{\theta})+G(\theta) \]

Hapa \(\tau=[\tau_s,\tau_e]^T\) inawakilisha shoulder na elbow torque vector, \(\theta=[\theta_s,\theta_e]^T\) joint angles, \(H(\theta)\) inertia matrix, \(V(\theta,\dot{\theta})\) centrifugal na Coriolis components, na \(G(\theta)\) gravitational torques.

Katika design simulation, amplitude ya 40° ilitumika kwa shoulder, 20° kwa elbow na movement frequency ya 1 Hz. Non-zero angle offset ya 20° pia ilizingatiwa ili kuzuia elbow hyperextension.

Anthropometric sensitivity analysis ilionyesha nini?

Ili torque requirement isibaki dependent kwa body type moja tu, watafiti waliongeza ±%10 variation katika height na body mass kwa male na female baseline anthropometries. Total conditions kumi na moja zilitathminiwa.

Highest maximum shoulder torque kwenye table ni 15,035 N·m katika scenario ya male height iliyoongezwa %10. Watafiti wanaeleza kwamba most typical adult body types ziko karibu na au ndani ya dynamic capacity ya device ya karibu 12 N·m, huku extreme height scenario pekee ikizidi limit hii kwa wazi.

Je, kuna important anthropometric inconsistency katika source?

Ndiyo. Mwanzoni mwa main methods text, simulation parameters zinaelezwa kuwa zimewekwa kwa “healthy U.S. male” wa 1,75 m na 76,7 kg. Katika sensitivity analysis inayofuata mara moja, 1,75 m na 90,3 kg imefafanuliwa tofauti kama “US Male”, huku 1,75 m na 76,6 kg ikiwa “Healthy Male”.

Muhimu zaidi, Appendix A inasema kwamba parameters za same two-link arm model ni za “average male subject (169 kg, 1.75 m)”. Value ya 169 kg haiendani na baseline anthropometric values za 76,6–90,3 kg katika main text. Value hii katika source haijabadilishwa kimya kimya.

Kwa nini double-parallelogram mechanism ilitumika?

Shoulder ni mojawapo ya joints zenye broad motion capacity katika human body, na joint-axis misalignment ni important design problem katika wearable rigid mechanisms. double parallelogram linkage (DPL) iliyotumiwa katika ASFD ilitumika kusaidia kuweka device rotation center karibu na shoulder center na kuruhusu end linkage kufikia wide workspace.

Figure 2 ya study inaonyesha jinsi DPL mechanism inavyohifadhi remote center of rotation katika maximum extension, maximum shortening na neutral positions. Figures 4 na 5 zinaelezea kwa detail jinsi mechanism ilivyosimplified na kumodeliwa kwa Denavit–Hartenberg coordinate systems.

Motor na power-transmission system zilidesigniwaje?

260 W Maxon EC90 brushless motor inayotoa nominal torque ya 1,02 N·m na EPOS4 70/15 motor controller zilitumika kama actuator. Kwa design target ya karibu 12 N·m, motor output ilihitaji kuongezwa approximately mara 12, hivyo researchers walitengeneza two-stage toothed belt-pulley system.

Power system pia ilikaguliwa kwa upper design condition ya 2 Hz frequency na 40° amplitude. Kwa 12:1 reduction, motion hii inahitaji motor speed ya karibu 640 rpm, ambayo iko chini ya motor nominal speed ya 1790 rpm.

Kwa nini motor haiko juu ya arm?

Motor na heavy power-transmission components zimewekwa kwenye ALICE-type backpack frame karibu na torso. Lengo ni kupunguza distal mass kwenye user upper arm.

Motor torque hupelekwa kwenye shoulder kupitia Bowden cable. Structure hii inaruhusu motor kubaki mgongoni huku DPL na end linkage zikifuata arm motion.

Back plate, Bowden cables na cable housings kwa pamoja zina 2,88 kg. Total mass ya DPL na end effector inayounganishwa kwenye user arm imetolewa kuwa 1,07 kg. Torsion spring imeongezwa kwenye DPL mounting region ili kupunguza effect ya second mass hii.

Actual efficiency ya two-stage transmission ni kiasi gani?

Angular velocities za motor shaft, first-stage output na second-stage output zilipimwa kwa three Movella DOT IMUs kwa sampling rate ya 120 Hz. Steady-state motion ya 30 seconds ilirekodiwa kwa kila frequency.

Measured reduction kwa first stage:

\[ N_1=\frac{\omega_{motor}}{\omega_{stage1}} \]

na efficiency:

\[ \eta_1=\frac{3.0}{N_1}\times100\% \]

Kwa second stage:

\[ N_2=\frac{\omega_{stage1}}{\omega_{stage2}} \]

\[ \eta_2=\frac{4.0}{N_2}\times100\% \]

Total transmission:

\[ N_{total}=N_1N_2 = \frac{\omega_{motor}}{\omega_{stage2}} \]

na total efficiency:

\[ \eta_{total} = \eta_1\eta_2 = \frac{12.0}{N_{total}}\times100\% \]

zilihesabiwa.

Total efficiency iliongezeka kutoka %82,9 katika 0,8 Hz hadi %90,1 katika 1,2 Hz. Total loss ilipungua kutoka %17,1 hadi %9,9. Researchers wanahusisha trend hii na improved belt engagement na reduced slipping katika higher speeds.

Shoulder range of motion ilitathminiwaje?

ASFD ilimodeliwa kama serially linked mechanism yenye six joint variables na position ya end linkage ikahesabiwa kwa Denavit–Hartenberg transformations:

\[ {}^{0}T_{6} = {}^{0}T_{1} {}^{1}T_{2} {}^{2}T_{3} {}^{3}T_{4} {}^{4}T_{5} {}^{5}T_{6} \]

Result matrix:

\[ {}^{0}T_{6} = \begin{bmatrix} {}^{0}R_{6} & {}^{0}d_{06}\\ 0^T & 1 \end{bmatrix} \]

inatoa position na orientation ya end effector relative kwa shoulder center.

Figure 8 inaonyesha calculated end-effector workspace katika transverse, sagittal na frontal planes. Katika color maps, red regions zinaonyesha maeneo ambapo mechanism ina larger movement coverage, huku black point ikiwakilisha initial point iliyochukuliwa kuwa shoulder center.

ASFD ilizuia natural shoulder motion kwa kiasi gani?

Katika workspace measurement, device ilitumika ikiwa unpowered na backdrivable. Shoulder motions za participant mmoja zililinganishwa kwa IMU katika conditions zenye na zisizo na device, na male participants watano pia walifanya similar motions qualitatively.

Flexion/extension na abduction/adduction motions ziliripotiwa kuonyesha overlap hadi %86,5 na %72,2 mtawalia na anatomical workspace. Rotation motions ni limited zaidi. Katika results section, internal/external rotation kwa pamoja inasemwa kuwa na overlap ya karibu %50,5 pekee, huku discussion ikitoa separately %26,7 kwa external rotation na %80,3 kwa internal rotation. Different expressions hizi zipo hivyo hivyo katika source.

Nini kilipatikana katika static-load experiment?

Purpose ya static experiment ilikuwa kubaini maximum torque inayoweza kubebwa bila system failure. Aluminum test arm ilitumika kuwakilisha human arm na weight ikaongezwa hatua kwa hatua. Kila weight condition ilirudiwa mara nne.

Maximum output torque iliyopimwa katika static test iliripotiwa kuwa:

15,09 N·m

. Relation kati ya torque na added mass ilikuwa approximately linear na \(R^2=0,99\) imetolewa katika discussion section. Maximum static value hii iko juu ya design target ya karibu 12 N·m.

System limit ilikuwa nini chini ya dynamic load?

Katika dynamic experiments, test arm iliendeshwa kwa 40° movement amplitude na total test mass ikaongezwa kutoka 0,697 kg hadi 3,417 kg. Kwa lower mass, frequency hadi 1,5 Hz iliwezekana; katika heavier conditions, maximum reachable frequency ilishuka hadi 1,1 Hz.

Katika heaviest dynamic condition, maximum torque ya 10,74 N·m ilipimwa kwa total mass ya 3,417 kg na movement frequency ya 1,1 Hz. Researchers wanahusisha kutoweza kufikia 1,5 Hz chini ya heavier loads na limits za system direction-reversal capacity na power-transmission structure.

Text inaelezea experiments hizi mahali fulani kama “six different masses”; lakini Table 8 inaonyesha seven total mass conditions, ikiwa ni pamoja na first condition ya aluminum arm yenye mass yake pekee.

Nani alishiriki katika human experiment?

Healthy male participants watano walijumuishwa katika human feasibility study:

• Age: 30 ± 7 years
• Body mass: 90 ± 22 kg
• Height: 1,80 ± 0,07 m

Participants walisimama na waliombwa wasiswing arms actively, bali waache arms passive pembeni. Condition hii ilichaguliwa intentionally; purpose ilikuwa kutest uwezo wa device kusogeza arm yenyewe bila user contribution. Kwa hiyo, experiment hii si real walking experiment.

Movement protocol katika human experiment ilikuwa vipi?

Target arm-swing amplitude iliwekwa kuwa 10°, hivyo total range of motion ya karibu 20° iliundwa. Test frequencies zilichaguliwa kuwa:

• 0,8 Hz
• 1,0 Hz
• 1,2 Hz

. Frequency iliongezwa na kupunguzwa hatua kwa hatua na protocol ikafanywa mara tatu.

Katika sentence moja ya source text kuna linguistically inconsistent expression kwamba “iliongezwa kutoka 0,8 Hz hadi 1,0 Hz na kisha ikarudishwa hadi 1,2 Hz”. Mwendelezo wa section hiyo hiyo na Figure 11 unaonyesha experimental sequence ya 0,8 → 1,0 → 1,2 → 1,0 → 0,8 Hz. Source-internal expression hii haipaswi kudhaniwa kuwa imesahihishwa kimya kimya.

Je, arm kweli ilifuata device motion?

Ndiyo, source data zinaonyesha kwamba passive arms za healthy participants watano zilifuata motion ya ASFD linkage kwa karibu. Arm na mechanism angle curves katika Figure 11a zinaoverlap kwa kiasi kikubwa. FFT-based power spectral density analysis pia ilionyesha kwamba applied na realized dominant frequencies ziliendana.

Best frequency matching ilisemwa kupatikana katika 1 Hz condition.

Shoulder torque ilihesabiwaje katika human experiment?

User arm ilimodeliwa kama one-degree-of-freedom pendulum katika sagittal plane. Estimated shoulder torque ilihesabiwa kwa:

\[ \tau_{sh} = I_{sh}\alpha + m_{arm}g\,l_{COM}\sin\theta \]

.

Hapa \(I_{sh}\) ni moment of inertia kuhusu shoulder center, \(\alpha\) angular acceleration, \(m_{arm}\) upper-extremity mass, \(g\) gravitational acceleration, \(l_{COM}\) distance kati ya shoulder na arm center of mass, na \(\theta\) arm angle iliyopimwa kwa IMU.

Angular acceleration ilihesabiwa kwa two-state discrete Kalman filter iliyotumika kwenye state vector \([\theta,\dot{\theta}]^T\).

Device torque ilipatikana vipi kutoka motor current?

Torque inayozalishwa na ASFD ilihesabiwa kutoka motor current kwa:

\[ \tau_{ASFD}(t) = N K_t \frac{i}{1000} \]

.

Katika source:

• \(N=12\): total transmission ratio
• \(K_t=80,7\ \text{mN·m/A}\): motor torque constant
• \(i\): motor current katika amperes

zimetolewa.

Effect ya frequency kwenye torque ilikuwa statistically significant?

Ndiyo. Repeated-measures mixed-model ANOVA ilitumika kwa torque analysis na significance threshold ikawekwa \(\alpha=0,05\).

Significant main effect ya frequency kwenye torque ilipatikana:

\[ F(1.15,9.26)=43.24,\quad p<0.001,\quad \eta^2=0.84 \]

Pia kulikuwa na significant main difference kati ya ASFD torque na shoulder torque iliyohesabiwa kutoka inverse dynamics:

\[ F(1,8)=18.19,\quad p=0.003,\quad \eta^2=0.69 \]

Interaction kati ya frequency na torque-calculation method iliripotiwa kuwa:

\[ F(1.15,9.26)=60.37,\quad p<0.001,\quad \eta^2=0.88 \]

.

Calculated ASFD torque ilikuwa significantly higher kuliko shoulder torque katika 0,8 Hz (\(p<0,001\)). Difference ileile ilikuwa significant katika 1,0 Hz (\(p=0,003\)). Katika 1,2 Hz, hakukuwa na significant difference kati ya torques mbili (\(p=0,318\)). Shoulder torque iliripotiwa kuongezeka kadiri frequency inavyoongezeka, na highest peak value katika 1,2 Hz ilibaki chini ya 10 N·m.

Arm range of motion ilibadilika na frequency?

Ndiyo. Frequency condition ilikuwa na significant effect kwenye range of motion:

\[ F(2,16)=69.640,\quad p<0.001,\quad \eta^2=0.897 \]

Range of motion ya mechanism linkage na arm zote mbili iliongezeka kadiri frequency inavyoongezeka. Hakukuwa na significant difference kati ya arm na linkage ROM values:

\[ F(1,8)=4.032,\quad p=0.080,\quad \eta^2=0.335 \]

Result hii inaunga mkono kwamba arm na device linkage zilisogea similarly chini ya experimental conditions.

Je, muscle fatigue ilionekana katika matumizi ya 20 minutes?

Hakukuwa na detectable systematic muscle fatigue katika short-term EMG assessment ya study. Healthy participants watano hao hao walivaa ASFD continuously kwa 20 minutes na posture na shoulder muscles zikafuatiliwa kupitia nine electrodes kwa Noraxon Ultium wireless EMG system.

Median frequency (MDF) na mean frequency (MNF) za EMG power spectrum zilitumika kwa fatigue assessment. Kwa right upper trapezius muscle, linear slope ilitolewa kama:

• MDF: 0,0074 Hz/s
• MNF: 0,0034 Hz/s

. Researchers wanatafsiri near-zero slopes hizi kama indicator kwamba hakuna detectable systematic frequency decline wakati wa 20-minute use.

Finding hii inahusu tu short-term 20-minute experiment ya healthy participants watano. Long-term wearing comfort, fatigue katika clinical populations au safety ya daily-life use haijaonyeshwa na experiment hii.

Matokeo yanayoungwa mkono na utafiti

• ASFD prototype iliweza kutengeneza programmable cyclic motion katika shoulder flexion/extension direction.
• Maximum torque ya 15,09 N·m ilipimwa katika static-load test.
• Katika dynamic-load test, maximum torque ya 10,74 N·m ilipatikana katika condition ya 3,417 kg na 1,1 Hz.
• Total efficiency ya two-stage transmission iliongezeka kutoka %82,9 katika 0,8 Hz hadi %90,1 katika 1,2 Hz.
• Passive arms za healthy male participants watano zilisogezwa na device katika frequencies za 0,8–1,2 Hz.
• Hakukuwa na statistically significant difference kati ya ranges of motion za arm na device linkage.
• Hakukuwa na detectable systematic muscle fatigue katika short-term 20-minute EMG assessment.
• Flexion/extension na abduction/adduction workspace zilikuwa less restricted kuliko rotation.

Matokeo ambayo utafiti hauungi mkono au haujatesti

• Study haionyeshi kwamba device inaboresha rehabilitation treatment.
• Effectiveness haijatestwa katika stroke, Parkinson’s disease, spinal cord injury au other clinical group.
• Human experiment haikufanywa wakati wa walking; participants walikuwa standing na arms passive.
• Results kutoka healthy males watano haziwezi kugeneralized directly kwa general population au patients.
• 20-minute EMG result haithibitishi kutokuwepo kwa fatigue katika long-term use.
• Unilateral prototype haionyeshi effectiveness ya bilateral arm-swing rehabilitation.
• External shoulder-rotation limitation haijaondolewa.
• Long-term mechanical durability na actuator life hazijatestwa comprehensively.
• Ability ya prototype kubadilisha arm swing wakati wa real walking imeachwa kama future-work topic.

Mbinu na Matokeo ya Utafiti

Experimental structure ya study

Main parameters zilizotumiwa katika arm model

Power-transmission efficiency

Measurement setup ya human experiment

Arm motion na device-linkage motion zilirekodiwa kwa separate IMUs mbili. IMU data zilitumwa wirelessly kwenye smartphone. Purpose ya sensors hizi mbili ilikuwa kutathmini independently kama kulikuwa na backlash, looseness au timing difference kati ya arm na mechanism.

Kwa participant safety, handheld dead-man switch ilitumika pamoja na software safety mechanisms.

Statistical analysis

Statistical procedures zilifanywa kwa SPSS v29. Repeated-measures mixed-model ANOVA ilitumika kwa torque na range of motion, na significance threshold:

\[ \alpha=0.05 \]

iliwekwa.

Sphericity assumption ilitathminiwa kwa Mauchly test; Greenhouse–Geisser correction ilitumika pale assumption ilipovunjwa. Bonferroni-corrected post-hoc comparisons zilitumika kubaini frequency pairs zilizohusika na significant differences.

EMG measurement

Short-term comfort na potential muscle fatigue zilitathminiwa kwa Noraxon Ultium wireless EMG system. Nine electrodes ziliwekwa kwenye posture na shoulder muscles, zikiwemo upper na lower trapezius, rectus abdominis, pamoja na anterior, middle na posterior deltoid kwenye right arm yenye ASFD.

Participants walivaa device continuously kwa 20 minutes. Median frequency (MDF) na mean frequency (MNF) za EMG power spectrum zilitumika kwa analysis.

Technical summary ya source-internal inconsistencies

• Main model text inatoa 1,75 m na 76,7 kg kama “healthy U.S. male”, huku anthropometric table ikitenganisha “US Male” 90,3 kg na “Healthy Male” 76,6 kg.
• Appendix A inaeleza model parameters kuwa za “average male subject (169 kg, 1.75 m)”. Value ya 169 kg haiendani na baseline body masses katika main text.
• Rotation-workspace result imeelezwa katika results section kama combined overlap hadi %50,5, huku discussion ikitoa external rotation %26,7 na internal rotation %80,3 separately.
• Dynamic-load method inatumia phrase “six different masses” huku Table 8 ikiorodhesha seven total mass conditions including unloaded aluminum test arm.
• Sentence moja katika human-experiment protocol inatumia expression “returned to 1,2 Hz” baada ya kutoka 0,8 Hz kwenda 1,0 Hz; experimental sequence katika section hiyo ni 0,8 → 1,0 → 1,2 → 1,0 → 0,8 Hz.
• Static-load test inaeleza system failure kwa conditions tatu, lakini discussion inataja “four criteria discussed earlier”.

Main methodological limitations

• Only five healthy males walishiriki katika human experiment.
• Participants hawakutembea wakati wa experiment.
• Arms zilihifadhiwa completely passive ili kutest highest-assistance-demand scenario.
• Prototype ni unilateral.
• Kuna clear movement limitation katika external shoulder rotation.
• 20-minute experiment si long-term wearability assessment.
• Long-term mechanical durability bado haijachunguzwa.
• Rehabilitation effect katika clinical population haijatathminiwa.

Maelezo ya Chanzo na Mbinu

Jina kamili asilia la utafiti: Design and Feasibility Assessment of a Prototype Wearable Upper-Limb Device for Facilitating Arm Swing Training

Waandishi: Ali Faeghinejad, Liam Hawthorne, Babak Hejrati.

Author order: Order katika source imehifadhiwa exactly.

Co-first / equal contribution: Hakuna co-first au equal-contribution statement katika source.

Corresponding author: Babak Hejrati.

Taasisi: Biorobotics & Biomechanics Laboratory, Mechanical Engineering Department, University of Maine, Orono, Maine, USA.

Aina ya chanzo: Peer-reviewed experimental research article; wearable rehabilitation robot design, mechanical modeling, prototype validation na feasibility study kwenye healthy humans.

Jarida: Actuators.

Mchapishaji: MDPI.

Bibliographic citation: Actuators 2026, 15(1), 27.

Article number: 27.

DOI: 10.3390/act15010027.

Official publication link:https://doi.org/10.3390/act15010027

Submission date: 22 October 2025.

Revision date: 13 December 2025.

Acceptance date: 24 December 2025.

Publication date: 3 January 2026.

Leseni: Creative Commons Attribution (CC BY).

Funding: National Science Foundation, grant 2145177.

Ethics board: Study ilielezwa kufanywa kulingana na Declaration of Helsinki na kuidhinishwa na University of Maine Institutional Review Board. Approval information imetolewa katika source kama “IRB 15 April 2019”.

Informed consent: Imeripotiwa kwamba informed consent ilipatikana kutoka kwa all individuals walioshiriki.

Data availability: Imeelezwa kwamba dataset inaweza kupatikana kutoka kwa authors upon request.

Conflict of interest: Waandishi walitangaza kwamba hakuna conflict of interest.

Author contributions: A.F.; human experiment, data analysis, software simulation na review/editing. L.H.; device design, static na dynamic load experiments, data analysis na first draft. B.H.; conceptualization, supervision, funding acquisition na review/editing.

Scientific-content boundary: Torque values, transmission efficiencies, workspace, movement frequencies, human experiments, statistical results, EMG findings na mechanical-design details katika Verianla article hii zinategemea examined primary study. Hakuna new experimental au clinical finding kutoka external sources iliyoongezwa isipokuwa bibliographic identity verification.

Main interpretation boundary: Study ni feasibility na prototype assessment. Human experiments zilifanywa na only five healthy male participants, standing na arms passive. Study hii haijaonyesha kwamba device inaweza kubadilisha arm swing wakati wa walking, kutoa neurological rehabilitation au kuboresha clinical outcomes.

Important inconsistencies ndani ya source

• Baseline anthropometric body mass imefafanuliwa differently kati ya 76,7 kg katika main text, 76,6 kg “Healthy Male” na 90,3 kg “US Male” katika sensitivity analysis.
• Expression “169 kg, 1.75 m average male subject” katika Appendix A haiendani na anthropometric values katika main text.
• Combined %50,5 expression ya internal/external shoulder rotation workspace na separate %26,7 external na %80,3 internal rotation values katika discussion hazijawasilishwa kwa namna ileile.
• Dynamic-experiment narrative inazungumzia six different masses, huku table ikionyesha seven total mass conditions including initial aluminum arm.
• Expression “returned to 1,2 Hz” katika frequency protocol haiendani linguistically na stepwise increase sequence ya experiment.
• Ingawa static system failure imefafanuliwa kwa criteria tatu katika method, discussion inazungumzia four criteria.