Hello My name is kyosuke futami. From Ritsumeikan university in Japan.
Today, I’ll present our project, Mindless Load Changer: A Method for Manipulating Load Perception by Feedback of Myoelectricity Sensor Information.
In recent years, systems using the feedback of sensor information have become widespread, and myoelectric sensor information have been used.
Myoelectricity changes in response to the amount of muscle activity.
So, it can help users understand the load of the body for various purposes, such as rehabilitation and training.
On the other hand, the psychological effects of sensor information feedback have been studied.
When users get sensor information feedback, mind and body unconsciously change to match the sensor information.
This happens even if the sensor value is modified and different from the actual value.
For example, the psychological effects of heart rate sensors can improve mental states and cognitive test results.
By using these psychological effects, it is possible to help users unconsciously change mind and body without their conscious effort.
From these, we assumed that the myoelectric sensor would cause a psychological effect that changes the load perception such as heavy and tired.
Then, we tried to change user's load perception by manipulating this psychological effect.
The proposed method modifies sensor information in two ways.
The first is "High load reproduction information".
This information increases the actual sensor value to creates the perception of a heavier load.
In this implementation, the actual sensor value was multiplied by 1.5.
The second is "Low load reproduction information".
This information decreases the actual sensor value to creates the perception of a lighter load.
In this implementation, the actual sensor value was multiplied by 0.5.
Here is the flow of the system.
First, myoelectricity sensor captures data. The sensor is attached to the biceps.
Then, the sensor value is modified and displayed in the form of 10 gage blocks.
In the evaluation, we evaluated whether the weight perception of luggage changes by modified sensor information.
First, in the Preliminary step, participants performed a task to understand that the sensor values change depending on muscle activity.
This task was to lift dumbbells of different weights from 1.5 to 5.5 kg as observing actual sensor values in time-series waveform of raw data.
Next, two pieces of luggage were prepared and their weight was 1.5 k g.
Participants lifted the luggage while observing modified sensor information and answered the weight of the luggage.
This task was performed for each luggage under different conditions of sensor information.
The high load reproduction information was about 8 gage blocks and the low load reproduction information was about 3 gage blocks.
This is because the actual sensor value when holding the luggage was set to be about 5 gage blocks.
This is results. Here, a larger value on the vertical axis means that the weight was perceived as heavier.
The overall tendency was that the weight perception changed to match the modified sensor information.
The difference in weight perception between conditions was about 10% of the luggage weight ( about 140 g).
Next is the tendency for each individual. The graph shows the value of High load information minus Low load information.
Therefore, the positive direction of this value means that participant's perception changed corresponding to the sensor information as expected.
The results showed individual differences.
For the ratio of tendency, Normal effect as expected was 62%, Reverse effect opposite to expectation was 23%, and No effect was 15%
The difference in weight perception between the conditions was up to 30% of the weight of the luggage (500g).
In this study, we demonstrated a feedback method for myoelectric sensors to unconsciously manipulate the load perception.
On the other hand, there were individual differences in the tendency of this phenomenon.
Therefore, this phenomenon can be used effectively by understanding what kind of tendency each user gets.
This study also showed some prospect. For positive prospect using psychological effects,
the proposed method is expected to support for changes in the load perception for various purposes such as physical work, training, and entertainment.
On the other hand, on the dark side, it can be assumed that such phenomena can cause problems that harm the user's mind, body, and experience.
Sensor values don't always show the truth and may become different from the actual values due to any reason,
such as accident of sensor malfunction, or intention of malicious third parties.
So, it is assumed that a mechanism to prevent such dark side becomes necessary in the future.
Thank you very much for your attention. @-@m