Hi everyone. I am Yuntao Wang from Tsinghua University.
I will present our recent research around haptic feedback for VR entitled MoveVR,
Enabling Multiform Force Feedback in Virtual Reality Using Household Cleaning Robot.
As more and more cleaning robots appear at our homes in recent years,
the robotic vacuum cleaner becomes one of the most ubiquitous robots.
We believe there are opportunities to leverage these domestic robots to conduct tasks beyond household cleaning.
So we introduce MoveVR, which leverages household cleaning robots
to provide force feedback for immersive VR experiences.
We implemented MoveVR using HTC Vive Pro with two trackers tracking the user’s hand position,
and HTC Vive controllers tracking the robot’s position and orientation.
We used Raspberry Pi 3B+ to control iRobot Create 2’s movement.
We used Alienware R5 laptop as the work station to render the VR environment,
and match VR content onto the robot, and configure the robot’s movement in the space.
To provide force feedback, proxies are required to deliver the force to the user.
We used everyday objects and materials to make the proxy fabrication method more easily accessible.
Three types of proxies are carry-on proxy that is carried by the robot,
and shared proxy that links the robot and the user.
user-driven proxy that is held by the user alone,
Components can be mounted to the robot using common adhesive tools such as touch fastener or tape.
We designed four force expressions, including tension, resistance, impact, and material rigidity.
This is achieved by changing the robot’s movement speed, rotation, position,
and carried proxy’s materials.
Specifically, MoveVR can create continuously changing tension with an elastic string between
the user and the robot as a shared proxy. Different levels of tensile strength can be
simulated by changing the distance between the user and the robot.
For a given type of elastic string and a particular surface that MoveVR operates on,
there is a maximum tension force that the robot could apply to a user.
It can be calculated by knowing the coefficient of friction, the robot’s weight,
and the distance between the user and the robot.
Therefore, we can calculate the maximum length and pitch angle using Hooke’s law to model the elastic string.
This will provide a guideline for future design on tension force feedback.
Similarly, MoveVR enables multiple levels of resistance force feedback by configuring
the robot’s active status or the direction of the motion.
Concrete resistance indicates static friction
MoveVR can simulate three levels of resistance forces on a specific surface where MoveVR operates on.
Heavy resistance means sliding friction when the motor is activated.
when the robot is locked in place with wheels placed vertically to the direction of the user’s push.
Light resistance represents rolling friction when the motor is deactivated.
We measured three types of resistance forces on three common surfaces shown in the table.
MoveVR can also simulate impact force feedback and material rigidity.
Different impact forces are generated by controlling the robot running into the human with different speeds.
While material rigidity is created by replacing the carry-on proxy with different material objects.
Lastly, MoveVR can also purposefully avoid contact with the user.
We refer to this type of interaction as evasive force feedback.
To explore MoveVR’s ability to provide multiple levels of distinguishable force intensities and directions.
We conducted a force perception user study with 12 participants.
The user study is to evaluate whether users can differentiate multiple levels of force feedback.
To be specific, tension force feedback includes five directions and four tensile strength.
Both resistance and impact force feedback include three levels of intensities.
Material rigidity include 5 classes using 5 different kinds of materials.
Results show that users can perceive multiple levels of force feedback accurately.
To further explore whether MoveVR can deliver more realistic and enjoyable VR experiences,
we conducted a second user experience evaluation study.
We compared our method with Barehand, vibrotactile haptic, and passive haptic solutions.
We used 7-points Likert scale to evaluate the realism, enjoyment, and easy to accept as the metric.
We built a VR game, including three scenarios within multiform force feedback were provided.
The result showed that MoveVR provides a more realistic and enjoyable user experience when
compared to commercially available haptic solutions such as vibrotactile haptic systems
while having the advantage of scalability in applications when compared to passive physical proxy alternatives.
To conclude, when comparing to existing VR force feedback solutions, our contributions have three folds.
1. For the first time, MoveVR enables multiform
force feedback using a common household cleaning robot with easy fabrication and assembly methods
using everyday materials, objects and tools. 2. Our force perception study demonstrates
that MoveVR can enable rich force expressions
with multiple levels of force intensity, force direction, and material rigidity.
3. Our user experience study shows that MoveVR provides a more realistic and enjoyable VR experience.
You can also scan the QR code for my recent research updates.
Thank you so much for your attention. Please refer to our paper for more details.