- Thank you all for coming to our presentation, and FacePush
had a demo last evening and I hope you are all enjoy
FacePush and had a good experience and I'm Wen-Jie and this
is my colleague Hong-Yu. Both of us are from National
Chiao Tung University in Taiwan and we will be presenting
FacePush introducing normal force on face with F and D's
and this work was stunning collaboration with Chia-En,
Hsin-Yu and Roshan from keio media design
from Japan and Liwei from NCTU.
First let us watch a short video of our work.
As you can see my colleague Chia-En is
wearing FacePush and playing the boxing game.
We simulate the haptic feedback of punches through
the normal force on face which is generated by FacePush.
Alright so why we want to simulate forces on face,
on the VR users face. Currently research in commercial
products are trying immerse the sense presence in the
virtual environment. Haptic becomes an important component
that can enhance the immersion. Lots or prior research
have explore this area like impact or use electrical muscles
simulator as a wearable device to simulate the haptic
feedback of impact and collision in VR.
The other works use handheld controller to simulate
haptics like NormalTouch and TextureTouch also the
haptic Links from CHI eighteen and both of them simulate
haptics through the handheld devices.
As we can see, many works were deploy on limbs through
wearable interfaces or handheld controllers.
However what about a face of the VR user.
There are some different kinds of modalities of haptic
feedback implemented VR HMD's, like haptic head
distributes multiple Vibrotactile actuators in three
concentric ellipses around the head to
provide intuitive haptic guidance.
Thermal VR demonstrates embedding of five thermal
modules on the HMD which produce hot and
cold haptic feedback. In the different
locations of similar stimuli had been
used as a directional cue in exploring the virtual world.
Other works focus on simulating head movements through
force feedback, like GyroVR contains a gyroscope attached
to the HMD generating tangential force, which provides
a feeling of inertia when conveying fast motion
or in other environment in VR.
So back to our boxing scenario we consider life through
the human face we can also enhance the
sense of immersion during VR.
There are still some more modalities of haptics haven't been
explore on the face, the face region. So we present FacePush
an HMD integrated with a pulley system that resulting in
a normal force on the user's face.
There are some more related work using normal force as
haptic output on wrist and body like Switchback presents
a use of pneumatic actuation and inflatable straps to
create compression stimulus on the wrist for notification.
Now work like Force Jacket a wearable jacket attached
with pneumatically actuated airbags and four sensors that
provide precisely directed force and high
frequency vibrations to the upper body.
Combine from above we decide to use normal force as the
haptic feedback on the horizontal axis of the face via HMD.
Also we want to deploy the special information concept
through FacePush. Now lets see how we implement FacePush.
We named the device at the center as torque generating
component and this is the main component of FacePush
for producing normal force.
So this video demonstrates how FacePush works.
Wait a second. So you can see the,
we demonstrates how FacePush works over here and the
different rotating angles produce different magnitudes
of the normal force on face. For the details of the
normal force generated by FacePush we will introduce that
part in the study section. Next we define two states
for the behavior of FacePush. The Neutral State represent
the top generating component or position parallel to
the direction of the user facing forward. At this moment
the rotate angle is zero and there is no normal force
inserted on the user's face. And the other state if the
motor are rotated we define this situation as Push State.
It represents the top generating component is rotated
and translates a belt pull into a HMD push.
At this moment we can assign the end goal to generate
different magnitude of normal force during push state.
So this figure shows each component of FacePush. The
DC motor works as the power source of FacePush and we
use rotary encoder to record position of motor
since we can assign the end goal where
the DC motor should rotate. And as we connect the
motor shaft and the belt of the HMD by coupling
and the clip on hinge then attach the top
generating component on both sides.
(mumbles)
This video shows how top generating component is assembled
in four parts are, you can see, and after the assemble
we just use the clip on hinge to
attach to the both side of the HMD.
After that we define two ways to use the push generated
by FacePush in our applications. The first time we
name it Discrete stimulus. The discrete stimulus
is an impulse representing a short duration
of contact and it increases and decreases
instantly in zero point five seconds.
And the other one we name it Continuous stimuli, the
duration of continuous stimuli covers the whole
application but the intensity is different among users,
and we use these stimulus depends on the
scenario of our applications.
So now we will show three different
applications of FacePush. The first one is,
the first one is a boxing demo last night. so we use
the discrete stimulus in the boxing game.
FacePush exerts corresponding pressure depends
on the different types of punch.
And diving, the next one is, (mumbles)
The second one is about diving example, and in this
example we try to simulate the water current acting on
your face when user is swimming. So we designed a
continuous stimuli of FacePush and its
strengths will be adjust according to
how fast and slow the user swims.
And the final one is about the
attention guidance and we use continuous
stimuli as directional cue in watching
a three sixty video. And users sometimes
miss important content when watching a
three sixty video so we used FacePush to remind
user where to look at during the watching.
And now we will introduce the user studies and our
resource of FacePush in the rest of the presentation.
- [Hong-Yu] Thanks Wen-Jie. In this work we carry out
user studies. In the first user study we find enjoyable
forces for FacePush.
In study one we counted three minor studies.
We define the appropriate pleasure
based on the results from the studies above.
Before we move on to our user studies we want to define
the mapping between rotating angle and then the pressure
acting on face. Therefore we place five sensors on the
face module as shown in the figure.
We obtain a linear equation of the average pressure
and the rotating angles are shown in the figure.
The result represents a single pressure sensor.
We use our pressure units which we use in proportion
to the actual force exerted on the user's face.
The total force can be approximated by
multiplying the pressure by the contact area of
the facial interface of the HMD.
After we come from the relationship between angle
and the pressure next we conduct a ADT study to
know the least pressure needed to be felt by users.
We conducted a standard two-down one-up staircase
study and then take the average of those five trials
to be threshold estimation. The threshold is two point
six nine four kPa which indicates FacePush must generate
at a decent weight or length such as participants begin
to feel a pressure on their face.
Next, we used discrimination threshold to find distance
between forces to be discernible. We used four base
pressures and offset pressures we defined
seventy five percent of users to be able to
distinguish between two stimuli as JND.
According to our results we find our best
pressure two point five seven five and
two point seven need the delta pressure
zero point five so lets the user can distinguish.
They are also the best pressure for comfort
experiment. Finally we evaluate the subject
rating of comfort and where the pressure comes from.
We choose six pressures from JND and
then use six starting score to
decide order for every participant.
The experiment is a repeated-measures design,
participants measure comfort with
seven point likert scale. The left picture
is about comfort the right one is a percentage
of force coming from face. It shows when the
pressure increases the subject comfort is reduced
and then a pressure comes from the head front.
Finally we decide to use two point seven kPa
as our criteria for pressure. We are also interested
in whether FacePush enhances user engagement
in virtual reality boxing experiences.
So we conduct study two. Each participant walks
through four levels and must evaluate the levels
the level realism and the enjoyment of the boxing game.
Afterward an open-ended interview took guest
general comments about the system.
The return is showing the figure.
The results shows FacePush enhances the enjoyment
and realism is our VR boxing game.
Most of the feedback are positive. Our participants
felt engaged with FacePush some parties were in
stayed alert sometimes feel not well
when FacePush pushing pressure.
We believe these results are due to a distance from
the eyes to a HMD. During pressure is reduced causing
the focus to change temporarily. It may bring out
nausea and blurred vision. However the participant
didn't report clearly. We consider the future research
can address these discomforts by automating the focus
adjustment. The limitation of FacePush is a weight
and noise. The weight can buy our motors
sometimes cause the HMD slide down a little bit
Where the motor is rotating it generates some noise.
This limitations are due to as we are using motors
However this can overcome by using different mechanisms
such as embedding shape memory alloys into a belt.
About our future work. We would like to achieve
the following two points. First,
Apply FacePush to other parts of the body.
For example wrist or finger. Secondly, Combine
FacePush with other simulated facial feedback
such as thermal. For example, when you try
experience the diving game you can
feel a temperature of water flow.
Finally we summarize FacePush into three contributions
We propose a pulley system FacePush to render
the haptic sensations through pressure acting
on user's face. Also we conduct studies to determine
which pressure is best generated. Third we use
three applications to show discrete
and a continuous, normal force.
Thank you for your attention and we
are happy to take any questions.
(clapping)
- [Host] Questions? Oh no that was not a
question. Very cool stuff, like
I like actuations in the face for
different reasons but I'm actually wondering
given that this is a very sensitive area if you
got any of the participants to comment on, not
discomfort necessarily, but surprise or something
because it is something that we don't really
expect and were very adjusted to.
- So actually we did some comfort studies to make
sure the pressure we generated to the face is
appropriate for users. So is that what you're
trying to address?
- [Host] I was just wondering if people had more
comments on the effect and the sensations in the
face because you know, some people are more
sensitive to them especially around the eyes
right that's a very sensitive region
- More sensitive mhmm..
- The second question I have on this is that by
moving the device around you're also creating
a visual effect if you think about it right,
yes you might loose focus which is a downside
but on the other hand you're creating sort of a
distortion for a brief amount of time. Is that
something that you maybe can play around with?
- Play around with you mean..?
- You're basically actuating the headset right?
So you're creating a visual sensation by
temporarily blurring the image or something.
- Actually we think this can be adjust by another
mechanism so maybe we don't use,
its very, it's not very significantly
affect the sense, what you see
in the VR so basically it (laughs)
- I think it could be a feature,
- Yeah feature
- Yeah and you should think about that. Okay Gitara
- [Gitara] That was really exciting work and
thank you for talk. I can imagine if you, like
while you're using HMD, you can feel, you can also
feel the push of sensation but also you can
feel the lateral force on the belt right?
On the HMD belt, if you pull it using the motors
I can imagine you can also render such another
side effect by using those motors and also I'm
also really curious to see with this device
you could also induce a different illusion effect
rather than push, is it possible to do illusion,
you know face pull with this device.
- Face pull mhmm. Basically HMD you can only tighten
up the belt and to create a push effect but the
pull effect is in the other direction so, we
haven't thought about it yet but for present
we try many different type of the feedbacks
like thermal and the pressure so we can
create more haptic feedbacks in the VR.
- Thanks so much.
- [Host] Okay and before you guys all leave
don't forget to spend those best talk tickets
on your way out so I want to thank all the speakers
and you guys again.