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Electro-active polymers as robot leg actuators



We found that electroactive polymers are very interesting and promising technology. The most known family of electroactive polymers are the ones that can bend, shrink or stretch if you pass small electrical current through them. The obvious use is in a field of robotics as a replacement for muscles. 

Here are some videos of existing laboratory models:

Actuating family of electroactive polymers is just one family of this materials. There are also materials that can change other characteristics when exposed to electrical current like viscosity (become sticky). This is another thing we want to use for this project.

What we want is to build something small but attractive based on electroactive polymers so we could later take a more serious role in filed of modern robotics. So our choice is tiny robot spider because it's easy to build in every aspect. 

The spider will have six legs and one utility arm. Each leg has 3 axes joint and 3 electroactive fibers that can shrink and relax to produce actuation in the right direction. So each leg will be controlled by 9 electroactive fibers. Fiber will be packed around metal bone like we have in our own arms - bones, and muscles around them. 

At the end of each leg, there will be a piece of electroactive gel that can change viscosity. This will enable it to climb the walls like a real spider.

Utility arm will have needles that spider itself can plug into the electric jack to recharge the battery. This way spider could stay on mission for a long time because he could sneak to some electric jack to recharge himself. 

The spider will be capable of connecting to the internet using 3G/4G or WIFI and will be able to transmit live audio/video from front and rear IC cam. The spider will be controlled by a human via the internet but will be equipped with some autonomous moment algorithms for certain complicated moment operation, like stabbing utility arm needles into the electrical jack, 180-degree turn, sidewalk...      


What can we expect from this project?

 - The spider can be mass produced. It can be offered to military, police, private eyes ... In the end, it can be a cool toy. We expect one spider model cloud cost 2500-3500$ when mass produced. So we can expect we can profit from selling spider model.

- Having operating spider model will help us go further with other more complicated things. It will give us valuable technical data we would use to later more complicated products. Like in producing human, dog, cat ... artificial prosthetic replacement.

- The final goal is a development of humanly sized droid equipped with artificial intelligence.


What can technically most difficult parts of development?

Crafting spider skeleton and bounding electroactive polymer fiber muscles to it is certainly not an easy task, but it is not most difficult.

One difficult task is choosing the right polymer compound. Some electroactive polymers react fast, some slow, some require more energy some less to operate. So we need to find the right balance. Spider needs to move decently fast and to consume energy as low as possible because it depends on battery.     

Spider body carries tiny computer powered by arm9 CPU and based on Linux operating system. That tiny computer will execute all tasks needed for spider body to operate and move. 

Most difficult part is building software to control moments of the spider. It has to synchronize and coordinate voltage on artificial muscles fibers so spider could move and stand steadily. Also, it has to be adaptive because force put to actuation of each fiber will be almost always variable and will depend on terrain spider moves on at the moment. This is also the most valuable thing that will emerge from this project for later use. When we have the right adaptive algorithm for controlling 63 fiber artificial muscles in the spider, we will be able to adapt it to control something more complex that has ten times more fiber muscles in it.    


So from reading this text you can see honestly one goal is giving something new to the world that can help humankind. It can become standard, and of course other is that it can make the profit. Maybe not much from spider project itself, but certainly from moment coordination software we will develop from this.