- [Announcer] Right, the third talk of the session is
Frictio passive kinesthetic force-feed output
and we have wow a plethora of different
collaborating institutions here.
In Teng Han is going to give the talk.
- Good afternoon my name is Teng Han
is proud to present our work.
Frictio passive kinesthetic force-feed output.
The work was done at Dartmouth College
under the supervision of Professor Shindong Young
and with collaborations from Shin Young
and (muffled talking).
It is commonly known that smart rings can be used
for subtle always available and eye-free interactions.
For example in this meeting scenario, the user
can rotate his ring to check his calendar
without being noticed.
The smart rings are mainly being used
for input purposes so far.
The feedback of using the smart ring is still very limited.
Current smart ring output mainly focuses on the light,
sound, vibration, skin drag or poking, thermal,
but these are really require
the substance shows users attention
and are often decoupled from the input mechanism.
Alternatively we present the Frictio, a smart ring device
passive kinesthetic force-feed back
for users rotational input.
Smart ring has three major advantages.
Frictio has three major advantages.
First it provides force feedback to users
in response to their input actions.
Second, this fits to the smart ring phone factor very well
and lastly different force profiles can be designed
to engage the interactions.
First to clarify the terminologies we used.
Uptake user interfaces encompasses both tactile
and kinesthetic for feedback.
The tactile feedback relies on the continuous skin senses
and is created by stimulating the
mechanical receptors of the skins.
The vibro tactiles of our smartphones
and the deep 3 beauty.
The fourth is showing on the left after figure.
Examples of tactile feedback.
On the other hand the kinesthetic feedback
relates to the feeling sense of the user's muscles
and joints.
The red figure shows kinesthetic force feedback in that one.
The user wants to move his finger to left
where he feels the resistant Force to the right.
And people often differentiate active and passive,
take feedback from either the users perspective
or the devices perspective.
In this work we differentiate active and passive feedback
from the user's perspective.
Frictio is an example of the passive force-feed back.
In this one users want to rotate their ring
while they feel resistant force from the ring device.
And now I would like to show you the design
of the first prototype right here.
This is the exploration diagram of our prototype.
It consists of an inner race for fingers to wear,
an outer race that is rotatable,
18 miniature magnets that are embedded in the outer race
and are evenly placed at 20 degrees apart
from each other with 18 magnetic posts.
And the brake pad that provides
the friction force to the outer race.
The motor and rack that controls the privation
and the movement of the brake pad.
And the proximity sensor that use the privation displacement
of the brake pad and two hall sensors
that detects the magnetic field strength
to induce the rotational angles and the directions.
The Frictio prototype was 3D printed.
As you can see in the finger there is a brake pad
that provides the friction force to the auto race
and the hall sensors to detect
the rotational direction and displacement.
Here's a video showing the Frictio in action.
The brake pad moves in response to users rotational input.
And the user feels the friction force feedback as a result.
To explore the capabilities of Frictio
we design six different force profiles.
These force profiles were rendered over
the rotational angle, time or both.
With no force the auto race is free to rotate
without any resistant force.
The Hardstop wheel prevents the user
from rotating the ring so that it can be triggered
after the user rotates a certain degrees.
What's resistant for the auto race is still rotatable
but it requires some extra force, or extra effort
from the user.
The friction provided by the brake pad
increases with ramp up.
And ramp down is opposite to ramp up.
The auto race is progressively easier to rotate
as users rotate the ring.
The Bump stops the auto race from rotation.
But the user needs to spend an
extra effort to overcome that.
So I would like to show you several videos
describing his first profiles in detail.
This is the No Force.
As you can see the brake pad stays still
and there is no resistant force provided from the friction.
This is the Hard Stop.
The brake pad stops quickly at a certain angle
and it prevents the auto race from rotating.
With the Resistant Force the brake pad stays in contact
with the auto race and provides constant friction
to the user.
With the Ramp-Up the brake pad can
move down slowly as the user rotates.
The Ramp-down is opposite to ramp up.
The brake pad moves up as the user rotates the ring.
With the Bump the brake pad drops quickly
and provide strong friction to the auto race
and the user needs to spend extra effort
in order to overcome that.
With these force profiles we designed
four different applications to indicate
how Frictio can be used for interactions.
Checking the time is often inappropriate.
Imagine this can be mitigated by using Frictio.
For example the ring is unmovable if the user
is late to the meeting.
Providing the rotational input usually requires
the Fine Motor Control or the
user's Continuous Visual Attention.
To mitigate this we can provide the uptake landmarks
by using the Bump feedback.
In this Lock application the users can unlock the device
by providing a series of alternating rotations.
The traditional gaming input can be mapped
to this rotational nature of the device.
In this game the users rotate with the Ramp-up
or the Ramp-down force feedbacks to indicate
the power and direction of the slingshot.
So receiving a call in the movie may disturb other viewers.
Frictio can be used as an eye-free co-display
by using some predefined force profiles.
So I just showed you a few interesting examples
but as a very new auto modality for smart rings
there are still many corrections that we don't understand.
For example whether users can perceive these force profiles
very well and whether the body motions and the
mant-over-growed can affect their perceptions.
To explore this we carried out a lab study
that explores whether Frictio can be used
as an effective output mechanism for smart rings.
We had three independent variables.
The first one was the force profile as described before.
And then the task users will rotate the ring
and random force profiles will be rendered
and user needs to tell as quickly as possible
which force profile they just felt.
So usually the body motions or the hand motions
impacted the user's perception for the force profiles.
So we designed the walking condition
where users keep walking at three kilometers per hour
on a treadmill while performing tasks.
And a standing condition where user stand stationary
on the treadmill while performing the tasks.
Besides mobility we also introduced secondary task
to induce user's mental workload.
The secondary task was designed from a modified stroke test
to make sure the secondary task was carried out
simultaneously with the primary task.
To know more details about the modified stroke test
you can refer to our paper but to be short
a color name is used to render a random color
and the users need to figure out whether the color name
and the color was a match.
With these studies I would like to point out several
interesting findings from the studies.
The first one: Most forced profiles could be
easily distinguished even under conditions
where users' physical or mental workload was high.
The average profile recognition accuracy was 94%
across all the users and all the conditions.
This figure shows the recognition accuracy
of the mobility condition and on
the secondary task condition.
The walking condition was labeled in the blue color
and the standing condition was labeled with the gray color.
The with-secondary task was on the left.
As you can see the profile recognition accuracy
was higher when the users were standing
and when there was no secondary task.
And this figure shows the average
profile recognition accuracy across
all the profiles we used.
We found out Hardstop was more accurate than the Ramp-down,
resistant force and the Ramp-up profiles.
But there was no significant effect
found between other pairs.
For the second finding we found
that physical workload didn't significantly
impact the response time.
The response time stands for the time elapsed
from the beginning of the force profiles
to the time when the users press the spacebar
to tell which profile they just felt.
In short, for the physical workload
which means whether users were standing or walking
but there was no significant impact.
For the third one, Frictio may not impact
the performance of a second parallel task.
And this figure shows the accuracy
of the secondary task across all the profiles.
Although the hard stop, bounce, no force
have significantly higher accuracy than the others,
for the secondary task.
But the average accuracy of the secondary task
actually reach 94.1% which is pretty high.
So with the study results
I would like to send several take-home messages.
The first one: the different Force profiles are easily
to be distinguished and they have different properties.
So they can be used for different applications.
For example the Bump and Hardstop maybe super
for urgent messaging applications because
they are easier to be distinguished.
And the second: We found that the resistant force
is actually the major source for confusion
with the others as a similarity to Ramp-up or Ramp-down.
So if designers want to use the Ramp-up or the Ramp-down
for the profiles it's better to avoid the resistant Force.
The last: Frictio could be useful for multitasking
because from the studies we didn't find
that the secondary task was impacted
by using the Frictio as the primary task.
So it potentially could be used for multitasking.
And for conclusion we presented the Frictio
and proposed using passive kinesthetic force feedback
as a variable smart push output.
The different force profiles can be designed
and be mapped to different applications.
With this I would like to thank my co-authors
and I'm happy to take questions.
(applause) Thank you.
- [Chris Mann] Oh hi, Chris Mann, MIT media lab.
So your mechanical design in that picture is very clever.
I'm not convinced about the applications but that's okay.
But the size of that that's something
I would put on my hands is just huge
So if you were going to actually make something like this
and try to get people to use them you'd need the size to be
about an order of magnitude smaller.
So based on your user study what would be
the most essential functions that you would need to have
in a ring like this?
- So this is the size of the prototype
is currently large for now.
This is actually one of the biggest limitations of our work.
So for the user studies
the device is both for the size of the user's finger
and the users mainly focus on detecting
which force profiles they felt during the rotating the ring
without looking at it and without hearing any sound.
So the central function will be which profile was that?
- [Chris Mann] But what's the single most important
thing you can in part by this mechanical feedback?
- Sorry can you speak louder I didn't--
- [Chris Mann] What is the single most important
sensation that you can impart through
the mechanical feedback?
I'm thinking about how to miniaturize this.
- I think for this one we mainly focus on
providing the friction force to the users
so when they rotate the ring they feel different frictions
and different patterns from the frictions.
- [Chris] Okay cool 'cause you can make that much smaller.
- Thank you.
- [Crowd Member] Let me just follow up with a question
that is maybe an extension of Chris's question and that is
as you miniaturize some things will be easy to miniaturize.
Others will be harder.
What do you think are the parameters
that will be easy to keep as you miniaturize
and what will be harder to achieve?
- So with our experiences of doing this project
we found that the motor patterns
were actually very hard to miniature,
but the brake pad this part could be easy to miniature.
But it's very hard to find a very very small miniature motor
that provides enough torque to rotate the ring.
Thank you.