Virtual surgery planning systems have demonstrated great potential to help surgeons achieve a better functional and aesthetic outcome for the patient, and at the same time reduce time in the operating room resulting in considerable cost savings. However, the two-dimensional tools employed in these systems today, such as a mouse and a conventional graphical display, are difficult to use for interaction with three-dimensional anatomical images. Therefore surgeons often outsource virtual planning which increases cost and lead time to surgery. Haptics relates to the sense of touch and haptic technology encompasses algorithms, software, and hardware designed to engage the sense of touch. To demonstrate how haptic technology in combination with stereo visualization can make cranio-maxillofacial surgery planning more efficient and easier to use, we describe our haptics-assisted surgery planning (HASP) system. HASP supports in-house virtual planning of reconstructions in complex trauma cases, and reconstructions with a fibula osteocutaneous free flap including bone, vessels, and soft-tissue in oncology cases. An integrated stable six degrees-of-freedom haptic attraction force model, snap-to-fit, supports semi-automatic alignment of virtual bone fragments in trauma cases. HASP has potential beyond this thesis as a teaching tool and also as a development platform for future research. In addition to HASP, we describe a surgical bone saw simulator with a novel hybrid haptic interface that combines kinesthetic and vibrotactile feedback to display both low frequency contact forces and realistic high frequency vibrations when a virtual saw blade comes in contact with a virtual bone model.  We also show that visuo-haptic co-location shortens the completion time, but does not improve the accuracy, in interaction tasks performed on two different visuo-haptic displays: one based on a holographic optical element and one based on a half-transparent mirror.  Finally, we describe two prototype hand-worn haptic interfaces that potentially may expand the interaction capabilities of the HASP system. In particular we evaluate two different types of piezo-electric motors, one walking quasi-static motor and one traveling-wave ultrasonic motor for actuating the interfaces.

In recent years, progress has been made regarding the use of tactile devices such as belts and helmets for navigational tasks. As most of the devices and solutions so far have focused on presenting one type of information at a time, the potential for tactile devices for simultaneous multiple tasks have yet to be properly explored. Based on such research, this study investigates various methods of presenting multiple simultaneous information using a vibrotactile head-mounted device for navigational tasks in a virtual space. The goal is to determine if it is possible to effectively present various simultaneous navigational information with vibrotactile feedback in a virtual space, and if so, determine guidelines for doing so while avoiding cognitive overload. Using a tactile head-mounted device known as the Perman Helmet various functions related to several navigational tasks in a virtual space were developed. These tasks were collision avoidance, object search and compass orientation. First a test was conducted to determine the most suitable solution for each given task. For each task three different types of solutions were developed, tested, and evaluated in an appropriate testing scenario. Afterwards, a second test was conducted to determine guidelines for how to combine those various solutions to present as much information as possible while avoiding cognitive overload. A new testing environment was created that incorporated all three tasks and various combination of the solutions were tested, along with two special configurations to test other factors. The results from the experiments shows that using several simultaneous vibrotactile signals representing different types of information is feasible and practical with at least 3 different types of signals. Furthermore, various types approaches and combinations have been considered and compared. Based on these findings, several guidelines when developing systems informing a user with multiple vibrotactile feedback signals have been proposed. These findings could help hasten the development of commercial and industrial multiuse vibrotactile devices, making it a relevant field of study. / Under senare år har en rad framsteg gjorts i utveckling av haptiska enheter så som bälten och hjälmar för navigation. Då fokus har legat på att en enhet ska lösa ett specifikt problem saknas det ordentlig utredning av haptiska enheters potential att hantera flera uppgifter simultant. Baserat på tidigare forskning utforskas det i denna rapport olika metoder att presentera multipla simultana informationsflöden via en vibrotaktil huvudmonterad enhet i syfte att navigera en virutell miljö. Baserat på om dessa metoder kan användas effektivt utan att överbelasta en användare tas därefter riktlinjer för sådana system fram. Med hjälp av en taktil huvudmonterad enhet kallad Perman Hjälmen togs en rad funktioner ämnade för att navigera i en virtuell rymd fram. Dessa funktioner var kollisionsförebyggande system, målsökning samt kompassorientering. För varje funktion togs tre olika lösningar fram och utvärderades i en lämplig miljö. Efteråt utfördes ett andra experiment för att ta fram riktlinjer för hur olika lösningar för olika uppgifter bör kombineras för att presentera maximal mängd information utan att överbelasta användare. En ny anpassad testmiljö utvecklades och olika kombinationer av lösningar till de olika uppgifterna utvärderades. Även två specialkonfigurationer togs fram för att testa specifika faktorer. Resultaten från experimenten visade att använda flera simultana vibrotaktila informationsflöden var praktiskt möjligt med åtminstone tre distinkta typer av flöden. Utöver detta har olika tillvägagångssätt och kombinationer övervägts och jämförts. Baserat på detta har flera riktlinjer tagits fram för utveckling och vidareforskning av system med multipla simultana vibrotaktila informationsflöden. Dessa slutsatser kan komma att bidra till vidareutveckling av framtida kommersiella och industrianpassade vibrotaktila enheter, vilket gör detta ett relevant forskningsområde.

Active safety systems that warn automobile drivers of various types of impending collisions have been developed. How these systems alert drivers when integrated, however, is a crucial component to their effectiveness that hinges on the consideration of human factors. Drivers' ability to comprehend multiple alerts presented through a haptic driver seat was investigated in this dissertation. Twenty-four participants, balanced for age and gender, drove an instrumented vehicle on a test-track while haptic alerts (vibrations in the driver seat) were generated. Drivers' ability to transmit the information conveyed by the alerts was investigated through two experiments. The first experiment investigated the effects of increasing the number of potential alerts on drivers' response performance. The second experiment investigated whether presenting haptic alerts through unique versus common locations in the driver seat affects drivers' response performance. Younger drivers (between the ages of 18 and 25 years old) were found to efficiently process the increased information contained in the alerts, while older drivers were not as efficient. However, it is foreseeable that older driver performance decrements may be assuaged when a crash context is provided. A third experiment evaluated the haptic driver seat's ability to alert distracted drivers to an actual crash threat. Drivers that received a haptic seat alert returned their gaze to the forward roadway sooner, removed their foot from the throttle sooner, pressed the brake pedal sooner, and stopped farther away from an inflatable barricade than drivers that did not receive a haptic seat alert. No age or gender effects were found in this experiment. Furthermore, half of the drivers that received the haptic seat alert lifted up on the throttle before returning their eyes to the forward roadway. This suggests these drivers developed an automatic response to the haptic seat alerts through their experience with the previous two experiments. A three-alert haptic seat approach, the intermediate alternative tested, is recommended providing specific design requirements are met. / Ph. D.

La stimulation électrique transcrânienne à courant direct (tDCS) est une technique non invasive de neuromodulation qui modifie l’excitabilité corticale via deux grosses électrodes de surface. Les effets dépendent de la polarité du courant, anodique = augmentation de l’excitabilité corticale et cathodique = diminution. Chez l’humain, il n’existe pas de consensus sur des effets de la tDCS appliquée au cortex somatosensoriel primaire (S1) sur la perception somesthésique. Nous avons étudié la perception vibrotactile (20 Hz, amplitudes variées) sur le majeur avant, pendant et après la tDCS appliquée au S1 controlatéral (anodale, a; cathodale, c; sham, s). Notre hypothèse « shift-gain » a prédit une diminution des seuils de détection et de discrimination pour la tDCS-a (déplacement vers la gauche de la courbe stimulus-réponse et une augmentation de sa pente). On attendait les effets opposés avec la tDCS-c, soit une augmentation des seuils (déplacement à droite et diminution de la pente). Chez la majorité des participants, des diminutions des seuils ont été observées pendant et immédiatement suivant la tDCS-a (1 mA, 20 min) en comparaison à la stimulation sham. Les effets n’étaient plus présents 30 min plus tard. Une diminution du seuil de discrimination a également été observée pendant, mais non après la tDCS-c (aucun effet pour détection). Nos résultats supportent notre hypothèse, uniquement pour la tDCS-a. Une suite logique serait d’étudier si des séances répétées de tDCS-a mènent à des améliorations durables sur la perception tactile. Ceci serait bénéfique pour la réadaptation sensorielle (ex. suite à un accident vasculaire cérébral). / Transcranial direct-current stimulation (tDCS) is a non-invasive neuromodulation technique which aims to modify cortical excitability using large surface-area electrodes. tDCS is thought to increase (anodal, a-tDCS) or decrease (cathodal, c-tDCS) cortical excitability. At present, there is no consensus as to whether tDCS to primary somatosensory cortex (S1) modifies somatosensory perception. This study examined vibrotactile perception (frequency, 20 Hz, various amplitude) on the middle finger before, during and after contralateral S1 tDCS (a-, c- and sham, s-). The experiments tested our shift-gain hypothesis which predicted that a-tDCS would decrease vibrotactile detection and discrimination thresholds (leftward shift of the stimulus-response function with increased gain/slope), while c-tDCS would increase thresholds (shift to right; decreased gain). The results showed that weak, a-tDCS (1 mA, 20 min), compared to sham, led to a reduction in both thresholds during the application of the stimulation in a majority of subjects. These effects persisted after the end of a-tDCS, but were absent 30 min later. Cathodal tDCS, vs sham, had no effect on detection thresholds; in contrast, there was a decrease in discrimination threshold during but not after c-tDCS. The results thus supported our hypothesis, but only for anodal stimulation. Our observation that enhanced vibrotactile perception outlasts, albeit briefly, the period of a-tDCS is encouraging. Future experiments should determine whether repeated sessions of a-tDCS can produce longer lasting improvements. If yes, clinical applications could be envisaged, e.g. to apply a-tDCS to S1 in conjunction with retraining of sensory function post-stroke.

This thesis research is concerned with the exploration, design, and validation of novel haptic technologies and signals that feel natural and meaningful in a calm and pleasant way. Our ultimate goal is to expand the possibilities of human-machine interaction by developing a single tactile display and a set of signals through a systematic design approach. It is generally a challenge to evoke a broad range of emotions with vibrotactile stimulation, especially at low signal intensities. During the first part of this thesis research, three types of prototypes were developed and explored using novel haptic technologies. The first was a circular array braille display consisting of eight small six-pin braille modules. The forty-eight pins were arranged in a circular shape to deliver circular tactile information such as time and direction. The second was a braille stick consisting of sixteen six-pin braille modules arranged in a row. The entire display could be easily grasped in the hand so that tactile information can be easily accessible. The third was a 3-by-3 electroactive polymer actuator array driven at high voltages that gives a subtle “tapping” feel on the skin. However, each of the three prototypes suffered from a limited range of expression and was not pursued further.<br> After the initial prototyping efforts, a 2-by-2 vibrotactile display, the palmScape, was conceived and developed. Custom-designed stimulation patterns based on natural phenomena that feel calm and pleasant were designed and implemented with the palmScape. We use text labels to set the context for the vibrotactile icons that attempt to capture and expresses natural metaphors through variations in signal amplitude, frequency, duration, rhythm, modulation, spatial extent, as well as slow movements. Fourteen participants evaluated twenty vibrotactile icons by rating the perceived valence and arousal levels. The twenty stimuli included sixteen custom-designed vibrotactile icons from this thesis research and four reference patterns from two published studies. The results show that our custom-designed patterns were rated at higher valence levels than the corresponding reference signals at similar arousal ratings. Five of the sixteen vibrotactile icons from this research occupied the fourth quadrant of the valence-arousal space that corresponds to calm and pleasant signals. These findings support the validity of the palmScape display and our signal design approach for achieving a calm and pleasant experience and the possibility of reaching a broader range of expressiveness with vibrotactile signals.<br> Future studies will continue with the design of signals that can express a broader range of metaphors and emotions through the palmScape, and build an emotional evaluation database that can be combined with other modalities. Our work can be further expanded to support an immersive experience with naturalistic-feeling vibrotactile effects and broaden the expressiveness of human-computer interfaces in media consumption, gaming, and other communicative application domains.

The project has the purpose of designing and developing a wearable haptic device for experiencing music through tactile vibrations on the body, and the result is the product concept BEATHOVEN and a completely new way of experiencing music.  Music is powerful, it touches our soul and gives form to our emotions. It captures the inner landscape of our minds, resonating in endless colours and nuances and shares it with others. Music has been a part of the human species for over 40 000 years and has played a fundamental role in our evolution and society; it is believed that we sang before we even spoke. Music, along with its aesthetic qualities, has throughout history been closely tied to our auditory perception. It was originally created and designed for listeners and has long been considered as something for the hearing. That perspective is starting to get more and more blurred out, however, and music is stepping out of auditory exclusivity. The general view of music today excludes over five percent of the world's population: people with disabling hearing loss. Hearing loss can impact a person’s life in many ways and one major impact is their ability to communicate with others. Music is another form of communication, and it is one where all of these people have thus far been excluded. The goal of this project is to design and develop a product that includes more people in music.  The project is carried out in collaboration with Pariception, a company specialized in research and development of assistive devices for people with deafblindness, and stems from one of their existing products: Good Vibrations. Good Vibrations is a wearable device for experiencing music through vibrations; it is a completely unique product and differs from all other solutions on the market. There are some brands, such as SubPac and Woojer, who have developed tactile music accessories, but these products are focused on enhancing a listening experience. Good Vibrations and BEATHOVEN are unique because they aim to convey the full musical experience and to be used independently from hearing. The current project brings Good Vibrations back to its basic concept idea, to redefine, refine, and design it into a usable, viable, and desirable consumer product: BEATHOVEN.   The project is made up of three main parts; to understand how the vibrotactile experience of music can be designed into a meaningful product, to understand how music can be conveyed through vibrotactile sensations on the body, and to know where on the body the vibrations should be conveyed to optimize the experience. To do this, we have created our own approach, adopting a mix of different design approaches such as design-driven innovation, human-centered design, embodied design, and aesthetic exploration. Research strongly indicates that it is possible to perceive aesthetic qualities within music through other senses than hearing, for example through stimuli such as tactile vibrations. To aid us in the development of the product, and to explore the aesthetic qualities of vibrations, we have defined a new research subject called Vibraesthetics.  The project has resulted in BEATHOVEN, a product concept featuring five vibrotactile actuators distributed to the chest and the neck. The product takes the input from any song or piece of music and transposes its frequencies to fit within 5-1000 Hz, which is the general range of human tactile perception. The music is further divided into three registers and distributed to separate and dedicated actuators. Some of the artist's original intentions with the music may be altered, but the richness of the experience is still there and available to anyone, regardless of their hearing abilities. / Målet med projektet är att utveckla och designa en bärbar haptisk produkt för att uppleva musik genom taktila vibrationer på kroppen. Resultatet av projektet är produktkonceptet BEATHOVEN och ett helt nytt sätt att uppleva musik.  Musik är kraftfull, det berör vår själ och sätter form på våra känslor. Det fångar vårt inre landskap, resonerar i oändliga färger och nyanser och delar det med andra. Musik har varit en del av den mänskliga arten i över 40 000 år och har spelat en grundläggande roll i vår utveckling och i vårt samhälle; mycket tyder på att vi sjöng innan vi ens började prata. Musik, tillsammans med dess estetiska kvalitéer, har genom historien varit nära knuten till vår hörsel. Den skapades ursprungligen och designades för lyssnare och har länge ansetts vara något för just hörseln. Den här synen på musik börjar dock mer och mer suddas ut, och nya sätt att uppleva musiken får ta plats. Genom den allmänna synen på musik vi har i dag utesluts dock över fem procent av världens befolkning: personer med nedsatt hörsel. Hörselnedsättning kan påverka människors liv på flera sätt och en viktig inverkan är på förmågan att kommunicera med andra. Musik är en annan form av kommunikation, en form där alla dessa människor hittills har blivit exkluderade. Målet med detta projekt är att designa och utveckla en produkt som inkluderar fler personer i musik.  Projektet genomförs i samarbete med Pariception, ett företag specialiserat på forskning och utveckling av hjälpmedel för personer med dövblindhet, och grundar sig i en av deras befintliga produkter: Good Vibrations. Good Vibrations är en bärbar produkt som möjliggör upplevelsen av musik genom taktila vibrationer; det är en helt unik produkt i sig och skiljer sig från alla andra lösningar som finns på marknaden idag. Det finns ett fåtal aktörer, som SubPac och Woojer, som har utvecklat taktila musiktillbehör, men de är enbart inriktade på att förstärka upplevelsen för den som redan hör. Good Vibrations och BEATHOVEN är unika av sitt slag då de eftersträvar att förmedla den fulla musikupplevelsen, oberoende av hörseln. I det här projektet tar vi Good Vibrations tillbaka till sin kärna, för att sedan omdefiniera, förfina och utforma den till en användbar, fungerande och åtråvärd konsumentprodukt: BEATHOVEN.  Projektet består av tre huvuddelar; att förstå hur musikens vibrotaktila upplevelse kan designas till en meningsfull produkt, att förstå hur musik kan förmedlas genom vibrotaktila förnimmelser på kroppen, samt att veta var på kroppen vibrationerna ska förmedlas för att optimera upplevelsen. För att göra detta, har vi skapat ett eget tillvägagångssätt, där vi har kombinerat olika designmetoder så som; design-driven innovation, människocentrerad design, embodied design och estetisk utforskning. Forskning visar starkt på att det är möjligt att uppleva estetiska egenskaper inom musiken genom andra sinnen än hörseln, till exempel genom taktila vibrationer. För att hjälpa oss i utvecklingsarbetet av produkten och för att bättre undersöka och förstå vibrationernas estetiska egenskaper har vi definierat ett nytt forskningsämne som heter Vibroestetik.  Resultatet av projektet är BEATHOVEN, ett produktkoncept bestående av vibrotaktila aktuatorer fördelade på bröstet och nacken. Produkten översätter vilken låt eller musik som helst och transponerar ner den till ett område på 5-1000 Hz, vilket är det allmänna omfånget för vår huds taktila uppfattningsförmåga. Musiken är sedan uppdelad i tre register och distribueras till separata aktuatorer. En viss del av konstnärens ursprungliga tankar och idéer med musiken kan förändras eller filtreras bort, men upplevelsens rikedom finns fortfarande kvar och är tillgänglig för alla, oavsett deras hörsel.

No description available.

Sensory adaptation is an important aspect of perception. A seemingly non-beneficial consequence of adaptation is that it produces perceptual illusions. For instance, following focal adaptation, the perceived separation between stimuli straddling the adapted attribute or region is often exaggerated. This type of illusion, known as perceptual repulsion, is both a consequence of and a clue to the brain’s coding strategies and how they are influenced by recent sensory events. Adaptation-induced perceptual repulsion has been well documented in vision (e.g. the tilt aftereffect) and to a lesser extent in audition, but rarely studied in touch. The present thesis investigated the effects of adaptation on tactile spatial perception using a combination of human psychophysics and computational modeling. In a two-interval forced choice task, participants compared the perceived separation between two point-stimuli applied on the forearms successively. The point of subjective equality was extracted as a measure of perceived two-point distance. We showed that tactile spatial perception is subject to an adaptation-induced repulsion illusion: vibrotactile adaptation focally reduced tactile sensitivity and significantly increased the perceived distance between points straddling the adapted skin site (Chapter 2). This repulsion illusion, however, was not observed when the intervening skin was desensitized with topical anesthesia instead of vibrotactile adaptation, suggesting that peripheral desensitization alone is insufficient to induce the illusion (Chapter 3). With Bayesian perceptual modeling, we showed that the illusion was consistent with the hypothesis that the brain decodes tactile spatial input without awareness of the adaptation state in the nervous system (Chapter 4). Together, the empirical and theoretical work furthers the understanding of dynamic tactile spatial coding as the somatosensory system adapts to the sensory environment. Its main findings are consistent with the adaptation- induced repulsion illusions reported in vision and audition, suggesting that perception in different sensory modalities shares common processing features and computational principles. / Thesis / Doctor of Philosophy (PhD) / Sensory adaptation can shape how we perceive the world. In this thesis, we showed that the perception of space in touch is pliable and subject to the influence of adaptation. Psychophysical testing in human participants showed that vibratory adaptation induced an illusion that expanded the perceived distance between stimuli on the skin. This illusion provides clues into how information about space in touch is normally processed and interpreted by the brain. In addition, we developed a computational model that used a powerful statistical framework – Bayesian inference – to probe touch on a theoretical basis. To the best of our knowledge, the present thesis provides the first combined psychophysical and computational study on the effects of adaptation on tactile spatial perception. Our findings suggest that touch shares some common information processing principles with vision and hearing, and adaptation plays a functionally similar role in mediating this process across the senses.

This thesis addresses a challenging problem: “how to let the visually impaired ‘see’ others emotions”. We, human beings, are heavily dependent on facial expressions to express ourselves. A smile shows that the person you are talking to is pleased, amused, relieved etc. People use emotional information from facial expressions to switch between conversation topics and to determine attitudes of individuals. Missing emotional information from facial expressions and head gestures makes the visually impaired extremely difficult to interact with others in social events. To enhance the visually impaired’s social interactive ability, in this thesis we have been working on the scientific topic of ‘expressing human emotions through vibrotactile patterns’. It is quite challenging to deliver human emotions through touch since our touch channel is very limited. We first investigated how to render emotions through a vibrator. We developed a real time “lipless” tracking system to extract dynamic emotions from the mouth and employed mobile phones as a platform for the visually impaired to perceive primary emotion types. Later on, we extended the system to render more general dynamic media signals: for example, render live football games through vibration in the mobile for improving mobile user communication and entertainment experience. To display more natural emotions (i.e. emotion type plus emotion intensity), we developed the technology to enable the visually impaired to directly interpret human emotions. This was achieved by use of machine vision techniques and vibrotactile display. The display is comprised of a ‘vibration actuators matrix’ mounted on the back of a chair and the actuators are sequentially activated to provide dynamic emotional information. The research focus has been on finding a global, analytical, and semantic representation for facial expressions to replace state of the art facial action coding systems (FACS) approach. We proposed to use the manifold of facial expressions to characterize dynamic emotions. The basic emotional expressions with increasing intensity become curves on the manifold extended from the center. The blends of emotions lie between those curves, which could be defined analytically by the positions of the main curves. The manifold is the “Braille Code” of emotions. The developed methodology and technology has been extended for building assistive wheelchair systems to aid a specific group of disabled people, cerebral palsy or stroke patients (i.e. lacking fine motor control skills), who don’t have ability to access and control the wheelchair with conventional means, such as joystick or chin stick. The solution is to extract the manifold of the head or the tongue gestures for controlling the wheelchair. The manifold is rendered by a 2D vibration array to provide user of the wheelchair with action information from gestures and system status information, which is very important in enhancing usability of such an assistive system. Current research work not only provides a foundation stone for vibrotactile rendering system based on object localization but also a concrete step to a new dimension of human-machine interaction. / Taktil Video

Smarta kläder är en kroppsnära teknik som består av kläder som har i sig integrerade/invävda sensorer vilka mäter kroppssignaler, arbetsställningar och rörelser och visar information om eventuella överbelastningar. Syftet i denna studie var att utvärdera prototyp 1 av ett smart arbetsklädersystem genom att utreda användarnas upplevelse (user experience) och användbarhet av prototypen samt prototypens påverkan på testpersonernas arbetsbeteende. En kombinerad studiedesign valdes. Den experimentella studien kompletterades med enkät och intervju. Tolv testpersoner deltog i undersökningen, fördelade lika på tre grupper: en kontrollgrupp och två experimentgrupper. Via tekniska mätningar samlades kinematisk data gällande: handledens vinkelhastighet och tummens tryckkraft; överarmens vinkel för höger- och vänster arm; överarmens vinkelhastighet för höger och vänster arm samt bålens vinkel vid fram- och bakåtböjningar. Signifikanta arbetsbeteendeförändringar kunde ej konstateras, men det förekom stora skillnader i de individuella resultaten i varje grupp. Dock kunde inte något specifikt mönster i arbetsbeteendeförändringar från de olika grupperna urskiljas. Hypotesen att arbetsbeteendeförändringar kan tillskrivas påverkan från prototypen stöddes inte av data. Resultatet från intervju- och enkätundersökning kring användarnas upplevelse och användbarhet visade att prototypen skattades som användarvänlig och användbar i sin helhet. Testpersonerna önskade förändringar i prototypens konstruktion gällande prototypens material och storlek, typ av feedback samt placering av sensorer. Vissa brister i design och utförandet av användartesterna och experimentmätningen konstateras och deras inverkan på studiens validitet och reliabilitet diskuteras. Rekommendationer ges gällande framtida testning av nästa prototyp utifrån de upptäckta bristerna. / Smart clothes are a group of technical aids that consist of clothing that has integrated/built-in sensors that measure body postures and movements and display information about possible physical overload. The purpose of this study was to evaluate prototype 1 of a smart workwear system by investigating its user experience and usability, as well as the impact of the prototype on the test subjects' work behavior. A combined study design was chosen. The experimental study was supplemented with questionnaire and interview. Twelve test subjects split in three equal groups participated in the study: one control group and two experimental groups. Through technical measurements, kinematic data was collected: angular velocity of the wrist and thumb pressure; right and left arm's angle; angular velocity for the right and left arm as well as the torso angle during forward and backward bending. Changes in work behavior were found. However, large differences in the individual results within each group were observed, with no obvious pattern of changes in work behavior between groups. The collected data did not support the hypothesis that work behavior changes can be associated with the impact of the prototype.  The result of analysis of the interviews and questionnaires about user experience and usability showed that the prototype was considered user-friendly and useful in general. Test subjects requested changes in the prototype’s construction regarding the prototype’s material and size, type of feedback and location of sensors.  Some shortcomings are observed in the test design, data collection and also in how the tests were conducted. Their impact on the validity and reliability of the study is discussed; accordingly, recommendations addressing the detected shortcomings are given regarding the future testing of the next prototype.