Hello, and welcome to this video presentation on A Review of Motion Sickness In Autonomous Vehicles.
This work has been done by myself, Abhraneil Dam, and my advisor, Dr. Myounghoon Jeon.
This is a review paper that utilizes the PRISMA framework to identify
relevant papers, perform a qualitative analysis and develop a research framework.
Firstly, we will discuss the scope of this work, and the PRISMA diagram.
Secondly, the qualitative analysis process. And lastly, the research framework that we
developed based on our analysis, and how it can be utilized to conduct future research on the topic.
Let's take a look at how the experience differs for drivers and passengers.
In SAE level 0 and 1 vehicles, the driver is in control of the vehicle
and is aware of the upcoming motions, compared to the passenger, who's merely experiencing the
motion of the vehicle as it occurs, and it's not necessarily prepared for them.
However, in SAE level 4 and 5 vehicles, the driver will begin taking on the role of a passenger.
The unique selling point of automated vehicles, is that it frees up the driver to engage in a
myriad of non driving related tasks or NDRTs or passenger tasks, PTs. These tasks will
further increase susceptibility to motion sickness, since engagement in these tasks
leads to a mismatch of the sensory inputs. Thus, motion sickness can be an issue
and automated vehicles, because they are expected to improve our lives by providing a
our lives by providing a better use of our time during surface transportation,
motion sickness presents a significant hurdle towards this goal. If passengers are not
ultimately comfortable while using an automated vehicle, their adoption will be slow and limited.
Motion sickness might not be apparent when testing out an automated vehicle,
like many ergonomic features that are not apparent while test driving a regular vehicle,
but become clear with usage over time. We suspect motion sickness in automated
vehicles to be a similar challenge, and that describes the scope and motivation for this work.
Our hope for this paper is to help early practitioners and students begin research
on this topic and contribute to this area. In increasing order of importance,
we hope to highlight the importance of human factors research on motion sickness,
identify the importance of testing different induction methods and their effectiveness,
develop a model that correlates the different measures of motion sickness,
and most importantly, encourage research on the different mitigation methods.
The PRISMA framework is shown on the left here. To identify papers, we searched popular human
factors databases such as Scopus, EBSCOHost, and ACM Digital Library. The search keywords used
were ‘(autonomous vehicles AND motion sickness)’ OR ‘(motion sickness AND mitigation AND autonomous
vehicles)’ OR ‘(motion sickness AND situation awareness AND autonomous vehicles)’. We examined
the abstracts to identify 87 papers, which were then screened to remove 10 duplicates. There was
no set time period for the searches, but the most relevant papers were found from 2006 to 2001.
Our eligibility criteria required the papers to approach the problem
from a human factors perspective that made use of a driving scenario to test potential
solutions. Papers that were strictly from an engineering or medical perspective were excluded,
although certain papers on vehicle dynamics, control algorithms, and
clinical drugs were included. After applying the eligibility
and exclusion criteria, 41 papers were identified in the final analysis process.
Motion sickness is a state of discomfort, resulting from exposure to motion
with physical symptoms, just malaise, dizziness, nausea and vomiting. It is often rated in terms
of its severity. Our analysis of the papers identified two main causation theories.
Primarily the Sensory Conflict Theory is described as the cause of motion sickness,
which explains that when we perceive one input visually and another conflicting input
through the vestibular system, there is a mismatch of the sensations of the brain.
The cerebellum of the human brain does not always expect this.
And that leads to the onset of motion sickness. The other theory is Anticipation Theory. Several
papers confirmed our hypothesis that unawareness of the upcoming motions of the vehicle
can lead to higher susceptibility to motion sickness; passengers,
because they are not controlling the vehicle, always tend to feel sicker than the driver.
Two popular induction methods were identified. Firstly, using virtual reality to immerse the
participant in a virtual automated vehicle. And secondly, using only real world driving.
In the first case, passengers wear a head mounted device for immersion in a virtual
environment as a passenger in a fully automated vehicle, with or without a driving simulator.
A key concern with this technique is the effectiveness, or the presence
of a confounding variable, because it has been established that using a VR headset or driving
simulator can use nausea by itself. A better induction technique is using real world driving
paired with the Wizard of Oz technique. Here the passenger is seated in a vehicle that is
driven by a human driver, unbeknownst to the passenger. While the vehicle
is driven on a serpentine road or in a defensive manner in an urban setting,
passengers are asked to perform a finding or tracking task on a screen inside the vehicle.
There are multiple subjective motion sickness measures, such as the Motion Sickness
Susceptibility Questionnaire - Short, the Motion Sickness Assessment Questionnaire,
the Misery Scale Continuum, and the Fast Motion Sickness Scale.
Each paper used a different measure and provided their own justifications.
However, there needs to be some form of validation that exists between these different subjective
scales. There is potential for this area to become an interest for future research.
There are also physiological and biological measures, such as electrogastrography,
galvanic skin response, and heart rate variability. But a single physiological measure
is not always conclusive to correctly measure motion sickness, but a combination of them can be.
All mitigation techniques revolved around the common modalities of information perception
visually auditorily, touch and olfactory. The most popular choice was visual cues;
the cues were designed to show the current or upcoming inertial state of the vehicle,
meaning the current direction, acceleration or breaking. However, this method requires the use
of peripheral vision, which can be disruptive when focusing on a more important primary task.
Auditory cues, on the other hand, have the advantage of not taking up the same mental
resources as visual cues. Also, hearing is omnidirectional which allows the use of spatial
audio to accurately provide predictive cues. This can also be a promising area of future research.
Another promising modality is haptics. Like auditory cues,
haptic cues can be used for a better dual task performance, since it does not compete
for the same mental resources as vision. However precaution must be taken to avoid frequencies
under 0.5 Hz or typically under 1 Hz, since it has been shown to actually induce motion sickness.
Finally, existing research provides some guidelines for mitigating motion sickness,
increased peripheral vision for the passengers and positioning displays in the greenhouse openings,
have been shown to be effective. Also, reducing head movements and matching the
passenger tasks with the driving route have also been recommended.
We identified common themes in the papers and develop a temporal research framework for any
researcher investigating this topic. First, there is the causation theory, which can have
an influence on the design of the induction and mitigation method that the researcher would want
to use. Second is the application of an induction method, and the measurement to confirm that the
induction of successful. After that researchers can apply a mitigation technique and measure
motion sickness scores again to test whether the method lead to a significant improvement.
Of all the methods investigated in the literature,
visual techniques and vehicle dynamics have been researched the most. There exists significant room
for improvement in testing auditory and haptic cues. Auditory cues can be provided continuous
non-speech sounds. The use of spatial audio and omnidirectionality of human hearing provides a
viable solution to the problem but future research is necessary to investigate this.
Vibrotactile or haptic cues can also provide a fast non-interruptive
technique of delivering information of the vehicles upcoming inertial state.
Lastly, visual cues can also be investigated further by studying display location and content,
to improve upon the existing solutions, and develop additional design guidelines.
This concludes our video presentation. It has been an honor to be to present
at this conference. We appreciate the chairs for their contributions,
and reviewers for their valuable feedback. Thank you for attending our video presentation!