Actuator for a wrist tremor suppression sleeve/exoskelet

[MattiasVDB]

Hey everyone,

We are currently working on a project to make a kind of sleeve that can suppress a big part of the wrist tremor that Parkinson patients or people with other diseases have. We are trying to decide to make this a partially active system, with only adjustable damping, or a fully active system with actuators that uses forces to counteract the tremor (out-of-phase). The problem is that we don't find any actuators that would be able to do this. It has to be very light and small, so that it could fit in just a normal long sleeve. And it would have to be able to deliver the needed forces.

We were looking at Electroactive Polymers, because these are sometimes used as artificial muscles, but it seems these wouldn't be able to deliver the necessary forces. We were wondering if anybody here knew about a kind of actuator that would be an option in this project? Or maybe a kind of electroactive polymer that could work?

Thanks to everybody who wants to help us realizing this product that could help many people around the world!

 

[Nidum]

What is the configuration needed ?

In particular - is this a small version of something similar to a contracting blood pressure monitoring sleeve or are more complex movements needed ?

 

[MattiasVDB]

It's not really similar to a contracting blood pressure monitoring sleeve. It needs to be able to give a moment force arround the wirst joint in both vertical and horizontal direction (but we can install multiple actuators, so per actuator only one of those moment forces are needed)

 

[Nidum]

Thanks for clarification .

Are there any pictures or drawings available ?

How much movement needed and what level of forces ?

 

[MattiasVDB]

At this moment we don't have any drawings yet, sorry about that.
The movement needed is the whole movement a grown up can do with his wrist. And we don't have any measurements yet of the forces, but you can make a guess by seeing how you would move your wrist when you fake a tremor.

 

[Manuel Aguilar]

This sounds interesting.
Have you considered magnetorheological dampers?

 

[MattiasVDB]

Yes, we have and this is absolutely an option as a semi active system, but we were looking for actuators for a fully active system that can deliver real counterforces.
Btw for if we decide to go for a semi active system, do you have any idea where we could buy these MR dampers? Because at the moment we don't find any companies that produce finished ones

 

[Manuel Aguilar]

I have read they are productized on high end race cars for active suspension control, but I have not seen anything on reduced size actuators so most probably they need to be designed (a new venture probably? ).
Are you making a glove like carrier for this?
How do you plan to trigger the reaction force?

 

[rbelli1]

You are working with a system with actuators built in. Do you have the option of electrically stimulating the muscles in opposition to the unstable biological signals?

BoB

 

[gjonesy]

This is a terrible disease, I have seen it first hand. My old land lord had Parkinson and his tremors were so bad at times he had to call me to come unlock his door for him simply because he couldn't hold steady enough to put the key in the lock. His doctor came up with a simple solution. A Neoprene brace with ridged but flexible plastic staves just for the right arm (from hand to shoulder). It was bulky but he could hold steady enough to do most ordinary task that were impossible when shaking uncontrollably. He was an older gentleman so it wasn't long after that he finally passed away, but stayed active up until about a month before he passed.