Haptiska gränssnitt. Haptiska gränssnitt. Innehåll: Känselsinnets olika funktioner. Hur fungerar känselsinnet biologiskt

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1 Haptiska gränssnitt Eva-Lotta Sallnäs Ph.D. NADA, Royal Institute of Technology Haptiska gränssnitt Innehåll: Känselsinnets olika funktioner Hur fungerar känselsinnet biologiskt Fenomenet känsel samt dess relation till övriga sinnen Hårdvara som ger känselåterkoppling Applikationsområden Användbarhet och haptiska gränssnitt 1

2 Haptiska system Ger kraftåterkoppling både taktilt och kinestetiskt. CyberGrasp Desktop PHANToM Reachin display system Haptic master Haptiska samarbetsmiljöer IPLab: Haptikverkstan 2

3 Känselsinnet Somatosensoriska systemet Taktila, temperatur, smärta Kinestetiska Haptiska Proprioceptiska 1.3 kvm skinn, 4-5kg skinn Skyddar kroppen från yttervärlden Ger känselintryck gällande kroppens position samt beröring Somatosensoriska systemet Tactile perception is defined as perception mediated solely by variations in cutaneous stimulation (Loomis & Lederman, 1986). Kinesthetic perception is defined as perception from joints and muscles,by limb movement alone, of hardness, viscosity and shape. Proprioception is the sense of position of the body in relation to gravity as well as our movement through space. Receptors in the vestibular apparatus are involved. 3

4 Haptic perception Haptic perception is defined as perception in which both the cutaneous sense and kinesthesis convey significant information about distal objects and events. Haptic system unifies input from many sources, e.g., position of fingers, pressure, into a unitary experience. Taktila sinnet Känselnerv Fibertyp Bästa stimuli Känselintryck Pacinian corpuscle RA II snabb vibration djup vibration Meissner corpuscle RA I picka på skinnet pickande Ruffini endings SA II tänjning av skin tänjning Merkel disc SA I kontinuerligt tryck tryck Meissner corpuscle Stimulus Epidermis Merkel s discs Snabb adaption Långsam adaption Dermis Ruffini endings Pacinian corpuscle 4

5 Det kinestetiska känselsinnet De sinnesintryck man får från muskler och leder. Positionen huvud och extremiteter har i förhållande till torso och tex fingrarnas position. Det närmaste man kan komma ren kinestetisk känslan, utan att bedöva alla nervceller, är att tänka sig att röra vid något med en fingerborg på fingret. Proprioception Sinnesintryck om vilken position kroppen har i förhållande till jorden. I innerörat finns vestibular sacs (utricle & saccule) som skickar signaler om acceleration, samt semicircular canals som skickar signaler om kroppens lutning. semicircular canals Utricle Saccule 5

6 Intermodal relations Vision is generally dominant over both touch and audition for the perception of spatial location. Vision is more effective than touch for perception of shape (Heller & Schiff, 1991). Audition is more effective than vision for the perception of temporally distributed events. Touch is at least as accurate as vision in the perception of texture. If vision is blurred people rely more on touch for perception of form. Intermodal relations The specific characteristics of any particular perceptual task should be considered, in relation to the specific properties of the sensory modality (modalities), that provides information for performance of the task (Heller & Schiff, 1991). The sensory modalities are specialised for different tasks, and that specialisation emerges more strongly as the complexity of the task increases (Freides, 1974). 6

7 Multi-modala system Stödjer flera modaliteter såsom syn, hörsel, känsel, lukt & smak. Gör systemet mer interaktivt. Ökar bandbredden för interaktion. Multi-media system Information via olika media såsom text, grafiska illustrationer, animeringar & video, men ofta via samma modalitet. Alternativa sätt att presentera information. Haptiska system PHANToM Three-degree-of-freedom. A stylus or tool handle may be substituted for the thimble. PHANToM+ a computer interpret the finger's position in three dimensional space and apply an appropriate and variable resisting force. Smooth walls, sharp corners, rubbery spheres, textured surfaces and friction. 7

8 Haptiska system Haptic master system Six-degree-of-freedom manipulator. The maximum payload of the manipulator is 2.5 kilograms,which is more than a typical hand. Hard surface, elastic surface, and fluid flow velocity. Haptiska system CyberGrasp is an force feedback system for the fingers and hand. The CyberGrasp is a lightweight, force-reflecting exoskeleton that adds resistive force feedback to each finger. The CyberGrasp system allows an operator to control a remotely located robotic "hand" and literally "feel" the object being manipulated. 8

9 Haptiska system The WCS II Joystick Taktilt system CyberTouch features small vibrotactile stimulators on each finger and the palm of the CyberGlove. Each stimulator can be individually programmed to vary the strength of touch sensation. The array of stimulators can generate sensations such as pulses or sustained vibration. 9

10 Taktilt system Braille display Känna papperskvalitet 10

11 Uppleva känslan av en växellåda Öva på att ta blodprov 11

12 Förstå seismiska data Simulera kirurgiska ingrepp Simulate the look and feel of eye surgery. Surgeons can practice procedures, as do pilots with flight simulators. Beside photo-realistic images of the eye, the simulator has linear tactile feedback for real-time "feel" of tool-tissue interaction. 12

13 Psykologiska verktyg Use of tactile augmentation to help distract burn patient from her pain during physical therapy..finns hur många exempel som helst.. Ultraljud på distans Molekyler Uppleva skulpturer i museum Känna på textilier Skapa prototyper.. 13

14 Perception av två-dimensionella objekt Det är signifikant lättare att känna igen tvådimensionella former med aktiv känsel än med passiv. Aktiv känsel när personen aktivt kontrollerar inhämtandet av känselstimuli tex vid läsande av punktskrift genom att röra fingrar och händer. Passiv känsel när personen EJ aktivt kontrollerar inhämtandet av känselstimuli tex om ett objekt trycks mot skinnet. Tactual Stereognosis Förmågan att känna tre dimensioner genom att undersöka objekt med händerna. Människor kan känna igen 96% av 2000 objekt utan att se objekten. - Sökande fas för att lokalisera objektet. Snabba svepande rörelser, inte särskilt taktila. -Positionsfas då händerna håller objektet för att etablera dess placering i förhållande till kroppen. - Undersökande fas för att mäta olika aspekter av objektet. Mikrorörelser med pauser vid kritiska punkter. - Olika rörelser utförs för olika syften, vikt, form, textur. 14

15 Manipulera objekt med ett verktyg När man manipulerar ett objekt aktivt med ett verktyg som vid tex titthålskirurgi, upplever personen efter ett tag att verktyget blivit som en förlängning av handen. Formen förmedlar funktionen - Underlätta val av knapp eller vred genom formen på knappen. -Använda texturer på knappar för att särskilja dem. Minimal möjlighet till förväxling av knappar. - Den känsla något ger förmedlar egenskaper hos produkten som tex kvalitet. 15

16 Guidelines för virtuella haptiska miljöer Design av objekt Undvik små objekt med många osammanhängande delar Gör rundade kanter snarare än skarpa God överensstämmelse mellan den visuella och haptiska modellen Perspektivet spelar roll för förståelsen Utnyttja det faktum att objektet är virtuellt Guidelines för virtuella haptiska miljöer Underlätta navigering Skapa referenspunkter (haptiska/visuella) Undvik att ändra referenssystemet Virtuella haptiska navigeringsfunktioner Haptisk vägledning, guide 16

17 Guidelines för virtuella haptiska miljöer Användarstöd Ge tydlig och snabb återkoppling Ge övningsexempel och möjligheter att imitera andra Medanvändare som lär ut genom fysisk guidning Var konsekvent Var uppmärksam på illusioner Minimera antalet regler som måste memoreras Haptic communication Feather, Scent and Shaker A new way of communication was a set of shakers. Two people had one shaker each and shaking one device caused the other to vibrate and vice-versa. Saw no graphical representation of the other person. (Strong and Gaver, 1996) 17

18 intouch The haptic system consisted of two devices that had three cylindrical rollers each. These rollers were linked respectively to each other so that direct continuous physical force on one of the rollers moved one of the rollers on the second device. Two people separated by distance could: passively feel the other person s manipulation of the rollers cooperatively move the shared rollers or fight over the state of the rollers (Brave et al., 1998) HandJive Small handheld and mobile device. Users could move parts in the device in nine discrete positions. People tended to compete if the haptic feedback was direct and continuous. Indirect haptic feedback and preferably discrete positions induced more cooperative behavior. People could learn complex patterns of Tactilese and started to improvise their own routines. (Fogg et al., 1998) 18

19 ComTouch Vibrotactile feedback that complement mobile voice communication. People developed a vibrotactile encoding system like Morse code. Emphasized what they were saying by synchronizing the tactile pattern with speech. Used vibrotactile signals to indicate that they intended to speak, turn-taking. People mimicked each other s signals in order to get other s attention, or as symbolically patting the other on the arm. (Chang et al., 2002) Haptic collaborative environment Haptic feedback improved subjects performance in moving a ring on a wire between two points without touching the wire with the ring. Haptic feedback increased subjects perceived togetherness. People more often though that they collaborated with a man when they had haptic feedback. (Basdogan et al. 2000) 19

20 Haptic collaborative environment A haptic cursor communication mechanisms in a 2D multiuser interface, PHANToM. - The users cursors could be felt and pushed. - One user could force another user to go the path that the first user goes. - A locate tool allowed a person to be guided to another user. - A grab tool allowed one user to force another user to move to her/him. People usually warned the other verbally before initiating haptic interaction More of the available space was used with haptic feedback for doing their task. Haptic feedback significantly increased (virtual) presence & perceived usability. (Oakley et al., 2001) Haptic collaborative environment Carry a stretcher through a detailed 3D virtual model of a chemical processing plant together with another person. The virtual model had obstacles in the form of pipework, vessels, pumps, valves other machinery and handrails. Two different haptic feedback systems were used, PHANToM and Argonne arm. Users could feel: pushing and pulling forces transmitted through the stretcher collisions between the stretcher and walls or other obstacles and a feeling of sliding along a wall. Haptic feedback made the joint manoeuvring of the stretcher easier. (Hubbold, 2002) 20

21 Haptic collaborative environments 21

22 Study 1. Apparatus Two Phantoms Two screens connected to one computer Two headsets, telephone connection Design Between group design 28 subjects Haptic vs. non-haptic Five tasks Study 2. Apparatus Two Reachin display systems Two desktop Phantoms One computer No verbal communication Design Within group design 22 subjects Haptic vs. nonhaptic Task: hand off 6 differently sized cubes 22

23 The collaborative environment in study 1. The collaborative environment in study

24 Conclusions from the two studies Supporting haptic force feedback in a distributed collaborative environment makes manipulation of common objects significantly faster (s.1) & more precise. People perceived their performance to be significantly better in the haptic environments. People perceived themselves to be significantly more virtually present in the haptic environments. But people did not always perceived themselves to be more socially present in the haptic environment. Fitt s law is applicable in collaboratively performed Fitt s law task and in both haptic and non-haptic environments. (Sallnäs et al., 2000; Sallnäs, 2001; Sallnäs & Zhai, 2003) The subjects own words.. In the environment where you feel, then you feel what the other person does, if both are at the object then you can adjust so that both persons help each other to move in one direction. But in the other environment you have no idea what the other person actually does. Then it can happen that you pull in different directions You signal that you are at (the object) then when you push from the front because you felt that yourself (that you had the object) It felt more insecure...(in the environment without haptic feedback) 24

25 Collaboration in virtual & haptic environments Social psychologists regard their discipline as an attempt to understand and explain how the thought, feeling and behavior of individuals are influenced by the actual, imagined or implied presence of others (Allport, 1954) Eva-Lotta Sallnäs Ph.D. NADA, Royal Institute of Technology 25