Comparing hand tracking and controller-based interactions for a virtual reality learning application

Abstract. Pseudo-haptic illusions can simulate haptic sensations using visual stimulus only. Pseudo-haptic feedback methods are valuable methods to simulate haptic feedback for virtual reality users. In this thesis, pseudo-haptic feedback is examined in conjunction with virtual reality training. Virtual reality training in assembly operations is becoming popular and it is important to raise awareness and knowledge on ways to fully gain and use the benefits of virtual reality in industrial use. Hand tracking can free the user from using controllers in virtual reality, but hand tracking can have other setbacks. The differences between controller and hand tracking based interactions are examined in this thesis. An experiment was conducted, where it was observed whether the weight of the controller had an effect on the pseudo-haptic feeling of weight for the user. Simulation of weight was done with a control-delay technique, in which the movement of the real hand is delayed in relation to the head mounted display’s displayed hand. This can create an illusion of weight for a virtual object. Quantitative, as well as coded qualitative data was gathered from the experimental application, and by using questionnaires. The paired data were analyzed using the T-test. A significant difference between the pseudo-haptic weight sensations was not found. However, it was found that the use of hand tracking was seen as more intuitive for the users, and yielded into higher feeling of presence. Controllers however, were seen as more robust, which was the main advantage of them. Suggestions are provided for future research, and limitations that were observed during the experiment are discussed.Käsi- ja ohjainperusteisen interaktion vertailu virtuaalitodellisuutta hyödyntävässä opetussovelluksessa. Tiivistelmä. Pseudohaptiset illuusiot simuloivat tuntoaistimuksia pelkän visuaalisen ärsykkeen perusteella. Pseudohaptiset menetelmät ovat hyödyllisiä tuottamaan haptisia tuntemuksia virtuaalitodellisuuden käyttäjille. Virtuaalitodellisuus on tullut yleiseksi opetusmenetelmäksi linjastolla työskentelevien operaattoreiden koulutustarpeeseen. Siksi on tärkeää ymmärtää ja kehittää menetelmiä jotka parantavat virtuaalitodellisuutta näissä olosuhteissa. Käsiperusteinen interaktio vapauttaa käyttäjän ohjainten käytöstä, mutta sillä on muita haittoja. Käsi- ja ohjainperusteisen interaktion eroja tarkastellaan tässä työssä. Työssä kuvataan koe, jossa seurattiin onko ohjaimen fyysisellä painolla vaikutusta pseudohaptiseen painon tunteeseen. Painon simulointi toteutettiin viivästystekniikalla. Tämä tarkoittaa sitä, että käyttäjän näkemän virtuaalikäden liikehdintää hidastettiin verrattuna käyttäjän omaan käteen. Tämä voi luoda painon tunteen virtuaaliselle esineelle. Koesovelluksen sekä kyselyjen avulla kerättiin sekä kvantitatiivista, että koodattua laadullista dataa. Tulokset analysoitiin T-testillä. Tulosten perusteella ei löydetty merkittävää eroa pseudohaptisen painon tunteen voimakkuuksista. Tulosten perusteella todetaan kuitenkin, että käsiperusteinen interaktio voi olla intuitiivisempi käyttäjälle sekä tuottaa käyttäjälle vahvemman paikkailluusion tunteen. Ohjaimien todetaan tosin olevan vakaampi interaktiomenetelmä; mikä on niiden suurin vahvuus. Lopuksi työssä annetaan ehdotuksia tulevaa tutkimuksia varten sekä keskustellaan nykyisen työn rajoituksista

Pilvipalveluiden käyttö paikantamiseen perustuvissa AR-sovelluksissa

Tiivistelmä. Tutkimus perustui paikantamiseen perustuvan AR-sovelluksen (Augmented Reality, AR) kehittämiseen mobiililaitteelle. Tällaisen sovelluksen toiminta perustuu laitteen sijaintiin sekä sitä ympäröivästä alueesta saatavilla olevan tiedon vertaamiseen toisiinsa. Paikannukseen perustuvan sovelluksen täytyy saada informaatio käyttäjän sijainnista sekä sovelluksen haluaman informaation liittyen käyttäjän sijaintiin. Kerättyään tarvittavan informaation, AR-sovellus osaa näyttää käyttäjälleen ympäriltä kerätyn tiedon lisättynä todellisuutena reaalikuvan päälle. Tutkimuksessa kehitetyn sovelluksen alustana päätettiin käyttää Android-käyttöjärjestelmää, jolle mobiilisovelluksen kehittäminen onnistuu helpoiten sekä tähän työhön sopivimmin. Sovelluksen kehittämiseen käytettiin Android Studio -kehitystyökalua, jonka käyttöön löytyy ohjeita developer.android.com nettisivustolta. Työssä hyödynnettiin pilvipalvelu Google Servicen kategorioittain tarjoamaa informaatiota eri paikoista. Sovelluksessa käytettävä informaatio rajattiin yhteen Google Places-API:n kategoriaan, jossa arvioitiin olevan sopiva määrä kohteita sovelluksen kehittämistä varten. Informaation piirtäminen mobiililaitteen näytölle toteutettiin vertaamalla osuuko laitteen ja kohteen koordinaattien välinen suora linja kamerakuvan rajaamalle sektorille. Tässä työssä onnistuttiin kehittämään AR-sovellus, joka paikantaa laitteen käyttäjää ympäröivät kohteet sekä esittää niiden sijainnin mobiililaitteen näytölle kameran luoman reaalikuvan päälle. Sovelluksen kehitys onnistui Android-alustalle vaivattomasti Googlen tarjoamien palveluiden avulla. Mobiililaitteet sopivat hyvin AR-tyyppisten sovellusten käyttämiseen niiden käytettävyyden ja riittävän tehokkuuden ansiosta.Using cloud services in a location based augmented reality application. Abstract. This research is based on developing a location-based AR-application (Augmented Reality, AR) for mobile devices. This type of application requires information about the device’s location, orientation and it must be aware of its surroundings. A location-based application must get information about the user’s location and necessary information relative to that position. After gathering this data, the AR-app can display the surrounding’s information on top of the real-time camera picture as an augmented reality. Android-operating system was used as a platform for the application. It is an easy development platform and it was appropriate for this study. AndroidStudio was used as the application development environment. It has a full online documentation in the following internet page: developer.android.com. Categorial information about nearby places from Google Services was used in this project. Data used in the application was limited to one of Google Places API category, that was estimated to produce an appropriate amount of results to develop the application. Drawing the information to the mobile device’s screen was accomplished by comparing if the line between the device and the place is on the camera’s current view. This paper includes a successfully developed application that can fetch the nearby places for the user and show their location in the camera’s real-time view. The development of the application for the Android-platform was an ease with the services offered by Google. Mobile devices are suitable for using ARtype applications because of their usability and adequate performance

In‐depth oxide scale growth analysis of B and Ti microalloyed AISI 304 in oxygen‐containing furnace atmospheres and CH₄ burn‐simulating furnace atmospheres

Abstract The effects of boron and titanium microalloying on scale‐layer formation and structure on AISI 304 austenitic stainless steel are studied. The research is focused on a steel slab’s oxide scale formation in a reheat furnace prior to hot rolling. The studied boron microalloying amounts are 7, 35, and 55 ppm and the studied titanium microalloying amounts are <100 and 400 ppm. In‐depth temperature and atmosphere tests span from 1100 to 1300 °C for an O₂‐containing atmosphere and 1100 to 1250 °C in an H₂O‐containing atmosphere, both using 25 °C increments. Research shows that microalloying 55 ppm B reduces scale growth at above 1175 °C in an H₂O atmosphere, all microalloying elements show significant scale growth reduction at 1175 °C in an O₂ atmosphere, microalloying 35 and 55 ppm B increases scale growth amounts at above 1225 °C in an O₂ atmosphere, while microalloying 400 ppm Ti reduced it. The inhibiting effect on scale growth that results from boron microalloying is tied to silicon oxide infiltration of the steel substrate

The atmosphere’s effect on stainless steel slabs’ oxide formation in a CH₄-fuelled reheating furnace

Abstract Utilising the oxyfuel practice for CH₄-fuelled combustion has positive effects on the emissions, efficiency and cost of high temperature furnace practices. However, especially in older installations, oxyfuel usage requires retrofitting and alters the atmosphere in which the oxidation of the steel occurs, when compared to using air as the oxidiser. Stainless steel slab oxide growth during reheating was studied in different atmospheres. The simulated post-burn atmospheres from oxyfuel, lean oxyfuel and air-fuel practices were used to compare oxide-scale layer growth and morphology during simulated typical AISI 304 stainless steel slab reheating prior to hot rolling. Thermogravimetric measurements, glow discharge optical emission spectrometer (GDOES) and field-emission scanning electron microscope energy dispersive X-ray (FESEM-EDS) methodology were applied to discern differences between oxide growth and inner oxide layer morphology between the three practices. Switching from air to oxyfuel practice at a single temperature had the same increasing effect on the scale formation amount as a 25 °C temperature increase in air atmosphere. Inner oxide layer depth profiling revealed C, Si and Ni to be the main elements that differed between temperatures and atmospheres. A morphology study showed Si and Ni behaviour to be linked to breakaway oxidation

The effect of boron and titanium microalloying on the scale formation of AISI 304 austenitic stainless steel in simulated walking beam furnace conditions

Abstract The effect of microalloying boron and titanium on AISI 304 austenitic stainless steel scale formation is studied. Thermogravimetric tests simulating walking beam furnace conditions are performed at temperatures of 800, 1100, and 1300 °C for 3 h on samples of AISI 304 steels with different alloying amounts of B and Ti. Scaling at 800 °C is negligible on all the samples, while scaling is clear at 1100 and 1300 °C. The thermogravimetric results show that even in small amounts, boron and titanium have an effect on scale growth rate. FESEM microscopy and accompanying EDS analyses are used to study oxidation area element composition. The FESEM images are also used to compare the oxidation zones’ area fractions of metal, pores, and oxide between different alloying amounts for the samples of 1300 °C tests. Calculations for scale formation activation energy are done based on the thermogravimetric data. The steel sample with the lowest alloying of boron and titanium shows a noticeably different growth rate, which is nearly linear in both the 1100 and 1300 °C tests. Differences between alloying amounts in accumulated scale during the 180 min period in kg m−2 are greater at 1100 °C than they are at 1300 °C

Oxide scale formation of stainless steels with different heating methods:effect of hydrogen as fuel

Abstract The evolution from natural gas usage to new technologies, such as the use of hydrogen as fuel or electricity-based heating, strongly influences the oxidation of the stainless steel surface in the reheating furnace. Thermogravimetric tests using different simulated combustion and induction reheating conditions are performed for austenitic AISI 301, AISI 304, and ferritic AISI 444 steel grades. Simulated furnace atmospheres in combustion methods are based on methane–air, methane–oxygen, hydrogen–oxygen, and methane–hydrogen–oxygen combinations. For induction simulations, air and nitrogen are used as furnace atmospheres. The results indicate that changes in heating conditions to H2-fueled combustion or induction only have a minor influence on the oxidation of the ferritic grade; whereas, their effects on the austenitic grades are more pronounced. The transition from a methane–air to H2–oxyfuel combustion increases the total oxidation by 1.7 and 4 times for steel grades 304 and 301, respectively; therefore, grade 304 can be considered better suited for transition for H2–oxyfuel use. The shorter induction heating considerably decreases the amount of oxide scale for austenitic grades, but the nitrogen atmosphere produces a subscale inside the steel matrix, which can hinder the descaling process

Oxide scale formation of EN 1.4622 and EN 1.4828 stainless steels during annealing and descaling behavior in neutral electrolytic pickling

Abstract Oxide scale formation during short-term annealing and electrolytic pickling behavior of ferritic EN 1.4622 and austenitic EN 1.4828 stainless steels are investigated. The annealing is performed at temperatures between 1000 and 1100 °C for ferritic and 1100 and 1200 °C for austenitic steel grade under humid atmospheres in simulated industrial process. Neutral electrolytic pickling, also referred to as neutral electrochemical pickling or the Ruthner Neolyte Process, is performed in Na₂SO₄ electrolyte, and pickling efficiency is evaluated visually and by image analysis of pickled surfaces. The results show that annealing conditions have a more impactful effect on the structure and the composition of the resulting oxide in the austenitic grade within the studied condition range. The thicknesses of the ferritic scales are mainly less than 0.4 μm, while almost all austenitic scales are thicker than it. In addition, the amount of silicon oxide formation inside the steel matrix of the austenitic and ferritic grades is highly different. Longer exposure times and higher temperatures promote scale growth during annealing, resulting in inefficient electrolytic pickling for the ferritic grade. For the austenitic grade, almost all steel surfaces are still covered with oxide scale after electrolytic pickling

Effect of simulated annealing conditions on scale formation and neutral electrolytic pickling

Abstract Scale formation of AISI 304 stainless steel during annealing at temperatures between 1100 and 1200 °C under a water vapor‐containing atmosphere is studied. Characterization of the oxide scale is performed with field‐emission scanning electron microscopy–energy dispersive spectroscopy (FESEM–EDS) and glow discharge optical emission spectroscopy (GDOES) and removal of oxide scale is done via neutral electrolyte pickling. The pickling conditions are kept constant and the effect of the annealing conditions and scale properties on the pickling result are examined. The effectiveness of pickling is evaluated using analysis FESEM images taken on polished sections of pickled surfaces. Research shows that the thickness, morphology, and composition of the oxide scale are dependent on annealing temperature and time. The thicknesses of the scale formed under the established conditions vary from 0.2 to over 30 μm, and morphologies between the chromium rich oxide layer and layered scale structure formed by breakaway oxidation. The pickling response of oxide scales remains good at all annealing temperatures with the shortest exposure time