Project Intro
Solo Major project at MSc & MA Innovation Design Engineering, Royal College of Art & Imperial College London
KEYWORDS: Sensation Substitution; Wearable Devices; Disability; Research.
METHOD & TOOLS: Human-Centered Design; EXP; Arduino;
DURATION: 1 month.
INSTITUTIONS:
Context
＃What if Prosthesis Users could get back the lost feeling?
There are 45,000 people who rely on prosthetic limbs in England alone. Across the UK, around 5,000 people each year have lower-limb amputations. With the development of technology, people can use the prosthesis to complete very complex tasks. And the natural control (EMG, MMG.etc) of the prosthesis is possible.
But still, they cannot get any sensation from the prosthesis. The Prosthetic limbs are just tools for them, they cannot ‘communicate’ with their prosthesis. This kind of ‘lost’ is not only taking away the functionality of their body, but also a gap bet between them and the surrounding. The sensory compensation will not only help the prosthesis users get better control of the prosthetic limb but also bring back their humanity.
But still, they cannot get any sensation from the prosthesis. The Prosthetic limbs are just tools for them, they cannot ‘communicate’ with their prosthesis. This kind of ‘lost’ is not only taking away the functionality of their body, but also a gap bet between them and the surrounding. The sensory compensation will not only help the prosthesis users get better control of the prosthetic limb but also bring back their humanity.
“I can feel my feet just as a phantom awareness, It feels
like they’re stuck inside rigid ski boots.”
like they’re stuck inside rigid ski boots.”
-Han Lin , Exoskeleton Robot User
“My legs are separate tools from my mind and my body,
they are not part of me.”
they are not part of me.”
-Hugh Herr, Professor, MIT
“There’s also a huge emotional impact, I spend as much of
my time in clinic dealing with the emotional adjustment of
patients as with the physical disability.”
my time in clinic dealing with the emotional adjustment of
patients as with the physical disability.”
-Todd Kuiken, Physiatrist
Secondary Research
I find three possible scientific directions could be applied into this project.
Neural Plasticity
Neural plasticity, is the ability of the brain to change continuously
throughout an individual’s life.t the single cell level, synaptic
plasticity refers to changes in the connections between
neurons, whereas non-synaptic plasticity refers to changes in
their intrinsic excitability.
throughout an individual’s life.t the single cell level, synaptic
plasticity refers to changes in the connections between
neurons, whereas non-synaptic plasticity refers to changes in
their intrinsic excitability.
Create a Sense?
The brain is locked in silence and darkness inside the vault
of the skull. All it ever has are electrical and chemical signals
racing around among its specialised cells – it doesn’t directly
see or hear or touch anything.
The internal subjective experience of a sense – also known as
its “qualia” – is determined by the structure of the data itself.
if we could feed a new data stream directly into the brain. it
will give rise to a new qualia.
of the skull. All it ever has are electrical and chemical signals
racing around among its specialised cells – it doesn’t directly
see or hear or touch anything.
The internal subjective experience of a sense – also known as
its “qualia” – is determined by the structure of the data itself.
if we could feed a new data stream directly into the brain. it
will give rise to a new qualia.
Sensory Substitution
Sensory substitution is a non-invasive technique for circumventing
the loss of one sense by feeding its information
through another channel.
It is hoped that sensory substitution systems can help people
by restoring their ability to perceive certain defective sensory
modality by using sensory information from a functioning
sensory modality.
the loss of one sense by feeding its information
through another channel.
It is hoped that sensory substitution systems can help people
by restoring their ability to perceive certain defective sensory
modality by using sensory information from a functioning
sensory modality.
Initial Concept
＃Sensory feedback system
Based on Sensory Substitution Theory, my initial concept is a sensory feedback system could give prosthetic hand user(elbow-below) the feedback of proprioception(senses of the relative spatial positioning of one’s body parts) and haptic perception. The system consists of three parts: sensors(an IMU sensor on the hand and pressure sensors on the fingertips), a coupling system(Microcontroller), and a stimulator(A vibration motor array on user’s back). When the posture of the prosthetic hand or the pressure on fingertips changed, the vibration motor array will generate different vibration pattern.
Field Research
＃Meet Alex Lewis
In order to get a deeper understanding of the prosthesis user, I collaborated with Alex Lewis in this project.
Alex is a quadruple amputee with the elbow of his right arm was saved, which gives him crucial control. He is also a motivational speaker, interior designer and the founder of Alex Trust.
Alex is an extreme user case.
This project mainly designs for his right prosthetic hand.
“The prosthetic hand still is very separate from me.
It doesn’t feel like a part of me.”
It doesn’t feel like a part of me.”
＃Interview & insights
Interviewing in Hampshire
I went to Alex’s house in Hampshire for the interview.
We talked about the feeling of the prosthetic hand, the neighbourhood and his daily life.
The key insights from this conversation:
-Alex is keen on social occasions.
-Rather than the feedback of the movement of prosthetic hand, Alex prefers emotional feedback.
-Alex is keen on social occasions.
-Rather than the feedback of the movement of prosthetic hand, Alex prefers emotional feedback.
As I know more about Alex, I found out that he is not just a motivational speaker, interior designer
and the founder of Alex Trust, he is also a friend, a father and a dog lover.
Friend Father Dog Lover
Based on these 3 scenarios, I decided to recreate 3 feelings of different emotional interaction.
-Handshaking
-Caress son’s hair
-Pet the dog
-Caress son’s hair
-Pet the dog
Handshaking Caress Pet dog
Prototyping & Experiments
In order to recreate these 3 emotional feedback, several prototypes were made for experiments.
Handshaking (Squeezing)
In order to replicate the feeling of handshaking, I used 3 different methods to make people feel like
someone is squeezing their arm.
-Two vibration motors
-One TENS machine
-One blood pressure monitor
In order to replicate the feeling of handshaking, I used 3 different methods to make people feel like
someone is squeezing their arm.
-Two vibration motors
-One TENS machine
-One blood pressure monitor
Caress & Pet the dog (Touch)
In order to replicate the feelng of touch, I used 2 different methods.
-One vibration motor
-One DIY soft sensor
In order to replicate the feelng of touch, I used 2 different methods.
-One vibration motor
-One DIY soft sensor
＃Experiments
To test the prototypes, I asked 10 participants to hold a prosthetic hand coupling different feedback methods and shake hands/contact with me. The results reflected in the final design.
Final design & Validation
The sensory feedback system contains of one air band, three vibration motors and several pressure sensors. Pressure sensors are distribute on the fingertips and the palm of the prosthetic hand. Users could get feedback when they do handshaking and caress with their prosthetic hands.
＃Validation
When I finalising the design of the system, I asked Alex to come to the studio and test the prototype I made. Here is his feedback.
＃Next Steps
As it is a one month project, there are still a lot of improvement need to be made, following are the next steps of this project.
-Comfortable & simple attachment
-Soft sensor exploration (Material)
-Speed of the air pump
-New Sensation?(Hug etc.)
-Soft sensor exploration (Material)
-Speed of the air pump
-New Sensation?(Hug etc.)