The work presented in this thesis focuses on the design and testing of a casualty extraction robot intended to stabilize the head and neck of an unresponsive person. The employment of robots in dangerous locales such as combat zones or the site of a natural disaster has the potential to help keep first responders out of harm's way as well as to improve the efficiency of search and rescue teams. After a review of robotic search and rescue platforms the Semi-Autonomous Victim Extraction Robot(SAVER) is introduced. The necessity of a device intended to support the head and cervical spine during transport on a rescue robot is then discussed. The kinematic and dynamic analyses of various candidate differential mechanisms intended for the head stabilization device are described, and the chosen mechanism is demonstrated in a proof-of-concept device. Following testing with a simple PID controller, it was determined an advanced feedback controller with disturbance rejection capabilities was required. Linear Active Disturbance Rejection Control (LADRC) was chosen for its effectiveness in rejecting perturbations and handling modeling uncertainties. The performance the proposed LADRC control scheme was compared with PID in simulation and the results are presented. Finally, a prototype of the device was designed and built to validate the functionality of the subsystem, and the results of the corresponding experimentation are discussed. / M. S. / Robots can help to keep first responders and medics out of dangerous situations by performing the rescue operation themselves or by collaborating with the field medic to make the process quicker and more efficient. The work presented in this thesis begins with a review of state-of-the-art rescue robots followed by the a brief description of the design of a Semi-Autonomous Victim Extraction Robot (SAVER) intended to rescue injured and incapacitated people. After the SAVER system is briefly described, the necessity of a device intended to support the head and cervical spine during transport is discussed. The head stabilization subsystem could also be implemented as a standalone device for use by paramedics to help free up valuable time that would otherwise be spent in manually stabilizing the head and neck of the injured person

Introduction: Musculoskeletal discomfort in the neck and shoulders is common among workers performing visually demanding near work, e.g., on a computer screen, and sustained low-level muscle activity during such work can lead to work-related pain. The relationships between visual demands and muscle activity and discomfort in the neck/shoulder region are at present unclear. Aim: The aims of this thesis were to determine whether neck/shoulder discomfort and trapezius muscle activity increases during visually demanding experimental near work, and to investigate whether eye-lens accommodation is a mediating mechanism behind increased trapezius muscle activity. Methods: The four papers included are based on two experiments with different visually demanding near work tasks (duration 5 and 7 min). Trial lenses of different diopters were used to manipulate the visual demands (i.e., induce more or less accommodation) and thereby create different viewing conditions. Monocular viewing, which does not require active convergence, was used to examine the isolated effect of accommodation. Eye-lens accommodation and trapezius muscle activity were measured continuously during the visual tasks, and in one experiment the participants rated their eye and neck/shoulder discomfort at baseline and after each visual task. Results: Neck/shoulder discomfort and trapezius muscle activity increased during the visually demanding near work and participants experiencing a greater increase in eye discomfort (compared with baseline) also developed more neck/shoulder discomfort with time. There were no significant differences in muscle activity among the viewing conditions, and no effect of isolated accommodation response within the monocular viewing conditions. Conclusion: These findings indicate that accommodation per se is unlikely to mediate trapezius muscle activity. Instead, the increase in trapezius muscle activity observed here may be due to a combination of high visual attention and enhanced requirement for eye-neck (head) stabilisation. Since these results suggest that neck/shoulder discomfort may aggravate with time when the visual demands are high, it is important to provide good visual conditions in connection with visually demanding occupations. / Introduktion: Muskelrelaterade besvär i nack- och skulderområdet är vanligt förekommande, framförallt hos individer som utför synkrävande datorarbete. En orsak till sådana besvär anses vara långvarig lågintensiv aktivitet i dessa muskler. Det är i dagsläget oklart om de belastningar som synsystemet utsätts för vid synkrävande arbete bidrar till ökad muskelaktivitet i nack/skulderregionen. Syfte: Syftet var att undersöka om experimentellt synkrävande närarbete påverkar muskelaktivitet och besvär i nack/skulderregionen, och att undersöka om aktivitet i trapezius muskeln (kappmuskeln) påverkas av ögats ackommodation, d.v.s. när linsens brytkraft förändras för att se skarpt på nära håll. Metod: De fyra delstudierna baseras på två laborativa experiment där försökspersoner (66 respektive 26 stycken) genomförde olika synkrävande uppgifter (fem och sju minuter långa). För att göra synuppgifterna mer eller mindre ansträngande för synsystemet användes linser med olika grad av brytkraft (dioptrier). Dessutom, eftersom monokulärt seende inte kräver aktiv konvergens, genomfördes tre av de fyra synuppgifterna i ena experimentet med ett öga för att undersöka den enskilda effekten av ackommodation. En autorefraktor mätte ögats ackommodation under synuppgifterna och aktiviteten i trapeziusmuskeln registreades kontinuerligt med elektromyografi (EMG). I samband med det ena experimentet skattade deltagarna sina upplevda ögon- och nack/skulderbesvär, både före experimentet (baslinje) och efter varje synuppgift. Resultat: Det synkrävande arbetet ökade både de självskattade nack/skulderbesvären och muskelaktiviteten i trapezius. De personer som upplevde en högre ökning av ögonbesvär (i förhållande till baslinjen), rapporterade också mer nack/skulderbesvär över tid. Det var varken någon signifikant skillnad i grad av muskelaktivitet mellan synuppgifterna, eller något signifikant samband mellan monokulär ackommodation och muskelaktivitet. Slutsats: Resultaten indikerar att ögats ackommodation, i sig, inte påverkar muskelaktiviteten i trapezius. Ökad muskelaktivitet i nack/skulderregionen i anslutning till synkrävande arbete kan istället bero på en kombination av höga krav på visuell uppmärksamhet och ett ökat behov av att stabilisera ögonen (huvudet) i förhållande till objektet i fokus (t.ex. texten på en bildskärm). Eftersom resultaten tyder på att synkrävande närarbete leder till ökade besvär i nack/skuldraregionen över tid, är det viktigt att utforma arbetsplatser och synkrävande arbetsuppgifter (t.ex. vid datorn) på ett sätt som främjar visuell hälsa.

The vestibuloocular reflex can be manually elicited by tilting or rotating the head. Manual techniques serve their purpose well and is the golden standard in the clinical work, but they lack control of velocity and movement pattern. However, motion simulation platforms enable automatic control of both velocity and movement pattern. One motion simulation platform, named BIRGIT, has been built at the Department of Clinical Neurosciences at Karolinska Institutet but has not yet been in service and require a performance evaluation. The objectives with this thesis is to evaluate the accuracy and precision of BIRGIT and evaluate how bodyweight and movement direction impact the performance. The thesis also evaluate whether it is possible to stabilize the head of the patient during the acceleration phase. Repeated measurements of acceleration with different loads, desired ac- celeration, direction and motion type (rotational and translational), are per- formed. Dummies are used to simulate bodyweight in the performance study and real persons are used in the head stabilization study. Analysis of variance (ANOVA) is the main statistical tool. The results suggest that the platform does not perform equally at dif- ferent load or directions and that there is a bias between desired and true acceleration. The main problems are an inclination of the rails, upon which the chair is mounted, that causes differences between directions and an un- desirable performance characteristic for rotational motions. The stabilization study suggest that the head can be stabilized. / Den vestibulo-okul ̈ara reflexen kan framkallas genom att manuellt rotera eller rycka p ̊a huvudet. Att manuellt framkalla reflexen fungerar i de flesta sam- manhang va ̈l och a ̈r standard i m ̊anga underso ̈kningar. Dock g ̊ar det inte att till fullo kontrollera vare sig hastighet eller ro ̈relsebana perfekt. Emellertid g ̊ar detta att kontrollera genom att anva ̈nda sig av en s ̊a kallad ro ̈relsesimu- leringsplatform. En s ̊adan platform, d ̈opt till BIRGIT, har byggts vid Institutionen f ̈or kliniska neurovetenskaper vid Karolinska Institutet. Denna har ej bo ̈rjat anva ̈ndas ̈annu d ̊a dess prestanda fo ̈rst beho ̈ver utv ̈arderas. Syftet med denna uppsats ̈ar att utva ̈rdera precision och noggrannhet hos BIRGIT. Dessutom, att utv ̈ardera hur kroppsvikt och ro ̈relseriktning inverkar p ̊a prestandan. I arbetet ing ̊ar ̈aven att testa om det a ̈r m ̈ojligt att stabilisera huvudet under accelerationsfasen. Repeterade ma ̈tningar av sann acceleration med olika last, riktning, bo ̈rac- celeration och r ̈orelsetyp (rotation eller sidledes) genomfo ̈rdes. Testdockor anva ̈ndes fo ̈r att simulera lasten i prestandatesterna och riktiga testpersoner anva ̈ndes i huvudstabiliseringsdelen. Variansanalys (ANOVA) var det hu- vudsakliga statistiska verktyget. Resultatet antyder att last och ro ̈relseriktning inverkar p ̊a acceleratio- nen och prestandan och att den sanna accelerationen alltigenom a ̈r la ̈gre a ̈n bo ̈raccelerationen. Det finns tv ̊a sto ̈rre problem hos plattformen, det fo ̈rsta a ̈r att uppha ̈ngningen till stolen lutar och detta resulterar i en skillnad mellan riktningarna (det g ̊ar fortare nedf ̈ors). Det andra problemet a ̈r ett cykliskt uppfo ̈rande na ̈r flera rotationsr ̈orelser skall fo ̈lja p ̊a varandra. Stabiliseringsstudien visade att det g ̊ar att stabilisera huvudet.