- Thank you for introduction.
Good morning everyone, okay good morning.
I'm a servitor from Japan, AIST.
And this project Magneto-Haptics
is a challenging and novel approach
to estimate and create haptic sensation
when we using magnet, permanent magnet.
So, in our daily life there's many use case
of magnetic attraction like using physical phenomena.
Our lives are getting more useful and functionable.
So I thought how we can use this
physical force for the context of HCI.
So this is the idea, I have some personal motivation
on magnets.
So first one is that the magnet is powerful
too in physical world and as like my previous work
named Flux Paper it is look like
normal postate or paper but actually
it has powerful magnetic radio backside
and it works as a an animated object
or robot in the physical environment.
So when connecting pieces of these paper
it gives force feedback by magnetic attraction or repulsion.
And one day when I was using magnets for building
blocks with Lego, I found magnet has clear
potential in physics, haptics, for user interface area.
So my question was, is possible to estimate and create
haptic feedbacks on re-using magnets.
Like sliding , pushing and rotating
for contrary barriers for computer devices.
And I also realized magnetic sensation
is like gradient curve, although actual
set up of haptic mechanism with magnet
is shown on the left side.
But human views it as like right side
so this is the key of this project
which is converting magnetic force
into visual and intuitive representation.
And, but this video shows a clear goal
of this project by putting transparent
plastic plate with embedded magnets,
and by sliding round magnet,
fingertips feels feedback corresponding
to the curved graph in yellow color.
So, the round magnet stops in the middle
of the slope of the pass, and go back to the right side
when it, the finger removed.
So it was achieved only using permanent magnet.
Before technical details I'd like to
summarize difference between ecto- approach,
electonic approach and magnet haptics approach.
There some differences between magnet haptics
and traditional electronic approach
such as motor and vibrations.
Of course magnetic force is passive,
so that's totally different from motor vibration.
However, most of time, when users
having some object and move it
and they get the haptic sensation from that object.
So passive sensation is also useful in
the mechanical design or fabrication.
And permanent magnet doesn't need
power supply and also save the space for it.
And it is also very easy for create physical functions.
So I used the permanent magnet for designing haptics.
So here's list.
Here listed research questions for me.
How to create to estimate haptic sensation?
And how to visualize represent, visually represent
magnet haptics?
And also is magnet haptic practical for haptic sensation?
And I'm going to solve and contribute
with near real time and scalable calculation method.
And intuitive and visual representation of feedbacks.
And user study for validation of magnet haptics.
Now you must be very curious about how to design
magnet haptics with your computers.
Then I show it.
The first process is to define some magnets
with parameters in the thickest file
like size, position, or rotation of each magnets.
Then the path where the moveable objects moves
also should be written in the same file.
And then put those parameters into calculation
program to get the result.
Then the program visualizes haptic feedback,
haptic force feedback in 3D.
And here haptic force feedback is defined
as haptic potential.
I describe this reason in later slide.
And next open SCAD helps generate
a still file for 3D printing.
And finally we can get fabricated object
with spaces for magnets inside.
So we can insert magnet inside the AVS plastic.
And, yes, that's the process of making
the blocks with magnet haptics.
And then first three steps iteration process
so we can iterate this process
and update for the desired haptic sensation.
And this is how the haptic sensation
is actually designed in the computer.
And, maybe, sorry.
With editing the left side the parameter
of rotations estimated haptics potential
showing a screen was change.
And it is also possible to create
Lego like block with the 3D model.
Now the program shows animation
of force feedback in 3D axis.
And finally this block is complete.
The block contains magnets on the several
different haptic sensations, so.
There is four types of haptic sensation,
each according to the shape and position of magnet inside.
So it is possible to combine some blocks
to explore new scenario of haptic feedback.
And yeah, like this.
And, this each four blocks was also used in the studies.
Okay, and lets move to the difficult part
of this paper, mainly physics and electro-magnetism.
So, please no sleep at the morning.
There is mainly two famous approaches
to calculate, or solve electro-magnetism.
The one is FEM, which is creates meshes
and solve the problem.
The second one is Dipole Method
which uses plots to, plots of vectors
in the arbitrary spaces.
So in this paper we selected Dipole Method to use.
Dipole Method is open boundary approach
so it is easier to define the largest space
for blocks or the embedded magnets.
And it is also rapid and still precise when high resolution.
And it is also open boundary and vector based
so the scalability is also high.
And here is some quick description on Dipole Method.
So, it is invited as a fast and approximate method
by Yung in 1998, and it uses differential
operation to skip integral operation.
So its very simple and fast approach.
And also it is used in CG animation research.
Then in this project Dipole Method was upgraded
with GPGPU calculation and matrix operation,
and intuitive visualization for more understanding
about the magnet haptics.
And this is a simple representation of magnet haptics.
Here is graph named Haptic Potential.
This is a new expression of magnetic force feedback
defined this paper.
If we insert some magnets more, its changed.
So, the upper sample is a general one
with the magnetic force.
So, because the force changes according
to the distance, but it also possible
to create the linear distribution on force.
So, it's a kind of the round contribution of magnet haptics.
Form this slide I describe how to
estimate haptic potential.
For Dipole Method we use the small magnet,
magnetic moment, shown as m here.
And then this formula of force F applied
to m in magnetic field B.
And next we need to think about magnetic force
caused by other magnet.
So, here B at m is calculated with this formula.
Then we can get a all B from each cells of magnet,
then we can get the summary of B from the other magnet.
And using those two formulas we can
observe the force between the magnets.
The Dipole Method converts those into another approximate
expression after the finished operation like this.
So the force applied to the piece of magnet cell
represents magnet moment is Fk.
And summary of force applied to left magnet
from right is now F, which is summary of Fk.
Finally we can get force between two groups of magnets
shown as two objects with embedded magnets.
If these summary of force between
summary of force with all combination of magnetic force
but if these still 3D expressions
so we have to convert it to another expression.
For getting intuitive and impressive
visual expression of haptic feedback
I've had work done by a force of the X-axis.
The shape of work done by the force
is very corresponding to the sensation on the finger
when the magnet is moved.
So haptic potential represents as P
which is gained by integral of Ft times cos sign theta.
I have to hurry up, sorry.
Okay, that's how to speed up this approach
with using GTU.
So, finally it get ten times faster
than CPU method, CPU approach.
Okay, to make sure the Dipole Method is valid
for magnet haptics, so here's a comparison with FEM.
There is some difference between our method
and FEM in Z-axis, but the potential, haptic potential
is also same, and with different
configuration of magnets is also same.
So I described to of three here.
And the last, we have to validate
magnet haptics in user study.
We hired nine people in our lab
and their average age was 35.6
and we gave enough basic information about these object
contains magnets, so it makes haptic sensation.
And we gave enough time to exercise
and we waited for answer, until submission.
The first user study was Distinction Test,
to ask subject to guess which is the correct answer
between A, B, C, D and the four types of curves, like this.
And the result is like this.
So I intentionally selected the similar curves
so some subjects confuse, but basically the result
was better than my expectation.
And on the left side of graph,
half of participant could answer correctly.
And, three made mistake one, and subject subject six
is not good at this sensation so,
she or he get the average down.
So, as a result it can be said
magnet haptics is technically distinguishable at least.
And also the Sensitivity Test with
record scale in five levels.
So, seeing this, each curve has different trend
and seems to be well distributed.
Okay, so until here I described all listed here.
And finally, prior to submission
I asked some people for some supports
about brushing up my idea and papers
so I'd like to, I'd like to take this
opportunity to thank them all so much.
Thank you for listening.
I'd like to take any questions.
- [Host] Wonderful, so great speaker, great talk.
We have time for a few questions
so please come up to the microphones, and yeah.
- [Questioner] So I have two questions.
So, first question is the country,
the design system is not very good, intuitive
GUI based, so do you have any plan to GUI based
design system, this is question one.
The second question is, the current system is just
generate static, the magnetic potentials.
Do you have any plan for any kinds
of dynamic magnetic field, that's the.
- Okay thank you for question.
For first one, maybe we can use 3D modeling
software like Brenda for pragines
so we can get GUI based interface
for designing magnet haptics I think.
But it is not my work so I just skip this part.
And for second question, I think it is possible
to make dynamic changing about magnet haptics
with changing the parts inside the box
or object, each by each.
Maybe it is possible with using electro-magnets,
but electro-magnets is not such powerful like
permanent magnets so I didn't expect that part in my, yeah.
- [Questioner] Okay, thanks.
- Yeah, thank you.
- [Dan] Hi, Dan Ashbrook, University of Copenhagen.
I'm curious, your setup here is you
put down some magnets in the software
and then you get this force curve,
the haptic potential curve.
- Yes.
- [Dan] Can you go in the other direction?
Can you define a curve and then
have the system calculate the kind of
magnets you would need to have?
- Sorry.
- [Dan] So can I input the haptic potential curve
and have output of a magnet arrangement?
- Yeah, I think it's possible but
I didn't solve that problem, maybe you can do that.
- [Dan] No, I'm really bad at math.
Maybe we can work together.
- Yes mathematics, thank you.
- [Host] Great, so let's thank our speaker
for this great talk.