Hello, my name is Yu-Hsin Lin. I am from National Taiwan University.
Today I would like to present JetController: High-speed 3-DoF Ungrounded Force Feedback Controllers using Air Propulsion Jets.
Haptic feedback enhances virtual experiences. Many haptic feedback types are provided one-to-one
to users, which may require a haptic device with the ability to actuate in higher frequency.
For example, automatic weapons in games such as Half-Life: Alyx
require the device to actuate up to 10-15Hz.
Even in the real world, the frequency of human button presses could be up to 6Hz
for an average person, according to our pilot study.
However, the past haptic feedback techniques that can produce strong force feedback
do not support those kinds of haptic feedback.
For example, hindered by the spin-up time of propeller-based approaches,
Thor’s Hammer could only produce 2Hz force feedback at 4N.
As a result, commercial products tend to use electric motors to support high-speed force feedback.
Xbox Wireless Controller utilizes two vibration motors to create ungrounded force feedback,
yet the feedback is unidirectional.
And the Falcon can generate 3 degrees of freedom
force feedback. However, it is not suitable
for most scenarios, such as virtual reality, due to its small operating space.
Therefore, we propose an air propulsion-based approach, JetController, a novel high-speed
3-DoF ungrounded force feedback technology.
JetController is the first high-speed 3-DoF ungrounded force feedback technology capable
of supporting the speed of human button presses and even automatic weapons in games and VR experiences.
Compared to propeller-based devices, JetController is 77% lighter and 89% more compact.
The system architecture of JetController is displayed as the figure.
Our system supports either air compressors or high-pressure portable air tanks as air suppliers.
In the next stage, electro-pneumatic pressure
regulators are used to manipulating air pressure. Finally, five high-speed solenoid valves are
used to control the direction of the resultant force.
Three horizontal nozzles are deliberately arranged 120° apart to avoid direct airflow
on the body during usage.
After creating a prototype of JetController, we found that the complex effects and tradeoffs
of several key design factors of a compressed air-based propulsion system have not been
established by prior literature. Therefore, we conducted series of system evaluation
to quantify the effects
and to decide which kind of tubing we should use and the use of nozzles.
We have four tubing configurations and two nozzle designs for a total of 8 configurations.
In our experiment setup, one of the JetController’s nozzles was attached to an L-Shape fitting
and mounted on a load cell to measure force magnitude.
Meanwhile, a decibel meter was placed at a 1-meter distance from the nozzle for measuring
noise level in stable input pressure. The measured force curve was recorded and
analyzed to identify three of its properties: maximum force, rise time, and fall time.
We found that a larger tubing size produces stronger forces under the same tubing length
and nozzle type.
And a shorter tubing produces stronger forces.
Last but not least, an open pipe produces stronger forces
compared to a pipe with noise-reducing nozzles.
Recorded data of JetController’s noise level also gave us some interesting findings.
It shows two clear groupings of curves, with the lower-noise curves being the configurations
with nozzles and the higher-noise curves being with open pipes.
This indicates that for a given force magnitude, the use of nozzles significantly reduced noise
level, but the choice of tubing size and length has minimal effect.
We measured the rise time and fall time as the periods from 10% of maximum force to 90%
of it and 90% of maximum force to 10% of it, respectively, based on a standard approach
to calculating rise time and fall time of analog impulses.
Also, we programmed our system to generate two types of impulses to demonstrate and validate
the capability of producing high-frequency impulses.
Lastly, we conducted several studies to evaluate the user experience of JetController.
There are three studies in our paper, an ADT study and two application studies. We recruited
24 participants, 12 females and 12 males age from 21 to 44.
Two high-rating commercial games, Half-Life: Alyx and Beat Saber are used in the paper
as testbeds for different purposes. For more details about implementation and
evaluation results, please refer to our paper. Thank you.