Hello everyone, I’m Jiang Chutian.
Recently I am conducting my research in Chinese Academy of Sciences Institute of Software.
Today I’m talking about Douleur: Creating Pain Sensation with Chemical Stimulant to
Enhance User Experience in Virtual Reality.
As we know, pain is a human instinct and plays an important role for safety.
Though haptic feedback has been studied for several years, as one of several haptic sensations,
pain sensation was not widely used in virtual reality.
Therefore, in order to fulfill the gap, we developed Douleur, a wearable haptic device
that renders intensity adjustable pain sensations with chemical stimulant: Capsaicin
The prototype of Douleur consists 6 partis, they are microneedling, microfluidic channel,
reservoir, micropump, and peltier with its heat dissipation system.
The application of microneedling forms microchannel on skin at first.
Then capsaicin solution, which stored in the reservoir, is pumped out and flows into the
microchannel, thus creates pain sensation.
To investigate the ability of controlling temperature and the volume, we conducted two
evaluations.
The volume control evaluation indicates that Douleur is able to control the volume precisely.
The temperature control evaluation shows that the temperature can also be controlled by
Douleur.
Therefore, we believe that Douleur can precisely deliver capsaicin solution to the skin, and
is able to maintain the skin temperature at a preset value.
Here we conducted two studies to evaluate our prototype Douleur.
In the first study, we investigated how the intensity level and type of pain are influenced
by different capsaicin concentration and temperature in time series.
For the pain intensity level, with the change of capsaicin concentration and temperature,
the intensity level of pain changes.
The higher the temperature and capsaicin concentration, the higher the pain intensity level.
For the type of pain, with the change of capsaicin concentration and temperature, the type of
pain also changes.
With the increase of temperature and capsaicin concentration, main type of pain changes from
shooting to hot burning.
In the second study, we investigated how immersion changes when combined virtual reality scenario
with the application of Douleur
We designed three scenes:” dog biting scenario”,” corrosive liquid scenario”, and” spilled
hot coffee scenario”.
In the first scenario, participants were required to play with a dog, and was suddenly bitten
by it.
In the second scenario, participants were asked to take a bottle of corrosive liquid,
and carelessly knocked it over.
In the third scenario, participant tried to get a cup of coffee stands on the edge of
a cabinet, unfortunately, coffee spilled out.
The result shows that, in scenario 1, the immersion level increases from 1.2 to 5.4.
In scenario 2, the immersion level increases from 1 to 4.6.
In scenario 3, the immersion level increases from 1.2 to 4.4.
Though not in the same level, the immersion increases with the application of Douleur.
For safety issue and efficiency, how to replace the used microneedling should be considered.
we should design a structure that permits rapid installation and dismantling of microneedling.
For instance, we could design a slot where microneedling can be inserted into and removed
from easily.
The temperature control system is also worth redesigning.
To improve the efficiency, we could utilize a smaller TEC plate with lower power requirement.
We could also choose a heat sink with better thermal conductivity or even redesign the
whole heat dissipation system.
How to reduce the tiredness of long-time wearing of Douleur also remains a problem.
One solution could be reducing the working hours of the device, which requires less power
and thus we could use less and lighter batteries.
Besides, we should also pay attention to the habituation of pain, which may influence the
pain feedback formed by Douleur.
High concentration and repeated dose of capsaicin induces an analgesia after initial pain sensation.
Therefore, when designing the experiment, the capsaicin concentration and interval between
tests should be considered.
It takes time to remove the pain sensation, in our study, we rinsed participants’ skin
and applied oleic acid, which takes 30-45 minutes to remove the induced pain sensation.
A more rapid method should be developed to better control the induced pain sensation.
People’s different pain sensitivity should be considered, future work should focus on
how to provide a tailored experience, which requires a calibration process.
Other feedback can be induced by chemicals, such as temperature, itching, etc.
Therefore it is possible to induce multi-channel feedback with the application of chemicals
How to make chemical-induced feedback controllable remains an open question.
Thank you very much for listening to my work and I’m happy to take any questions.