BioGripp 3.1 - Robotic hand

I built this hand because I was convinced that we could do even better than the 3D-printed ones. They are really good looking but they usually don´t have the strength to grip objects or they cannot stay a high number of uses.

The purpose of my project was to design a hand with a human-like movement which could grip 1kg and which had to be affordable even in mass production. The design was really a lot influenced by the production price. 

Mechanic :

The mechanical system which allows imitating the human movement with only one actuator per finger is patent pending. Each finger stays independent. In addition, the thumb can change is position to adapt to several grip strategies.

In comparison with the 3D printed hand, mine is designed for heavy duty. I am using gears in aluminum which allows me to use some powerful actuators. I work as R&D engineer for the pharmaceutical industry so I used these skills in the maker world.

I thought, from the beginning on, to the mass production and to reduce the cost to make my hand available for the most. For example, the pieces are the same for the right and for the left hand. This is only a question of assembly. I also limited the number of different pieces to get some volume prices.

Production :

Regarding to the production methods, I limited myself to the laser cutting. The rest of the pieces can be ordered on the internet. The laser cutting was a good way to make the prototypes in plastics and then directly the end version in aluminium. I had to limit my use of the 3D printer because even if this technic is perfect for the prototype it is then difficult to achieve the mass production.

In 2 years of development I produced nearly 20 complete prototypes and thanks to the laser cutter of the FabLab I could make it for a few €. A real prosthetic hand costs between 10 and 40 000€, I realized my aluminium prototype for less than 1000€.

R&D Tool :

The hand can be used for research in robotic, informatics or mechatronics for example. There are no other pre-installed sensors except the in-built potentiometers in the actuators but you have enough space to build your own.

The hand is designed to be upgradable. The only parts that I 3D printed are the fingertips. That way, you can make your own version according to your needs, for a sensor or anything else. You can print them yourself, in a FabLab or through a service like Shapeways for example. The hand is already compatible with the Servocity parts which allow a huge range of constructions.

Control :

The controlling system is based on an Arduino Nano. I developed several PCB to answer different needs.

• One PCB for prototypes allowing the user to build his own system.

• One shield for Arduino Nano with every needed element to control the actuators, including the position feedback. The control with feedback from the 5 actuators requires 25 pins but the PCB in the hand already include 15 additional pins to make the upgrades easier. The different PCBs are OpenSource as the Arduino code but they are also available in professional quality by Fritzing.

Next step :

Prosthetic :

The FabLab Berlin has a partnership with Otto Bock (the biggest prostheses producer worldwide) and I would like to show them my work. Maybe can my design lead to a new generation of prosthetic hand.

R&D Tool :

I would like to take contact with Robotshop Accelerator Program which could handle the production and the distribution of the hand. In addition Firgelli motors and Servocity parts are already distributed by Robotshop. That would permit to Universities and to Makers to buy this cost-efficient hardware to build their own project.

Feelings:

What I like in this project is to see the hand moving. I find the movement really nice and I get not tired playing with it.

But, what was really moving was at the Maker Faire Berlin. The public already showed a real interest for my hand but I also met two people with the need of a prosthetic hand. They were impressed about the movement and the strength that I achieved with my design. They also confirmed that what was limiting was the price of the professional ones (From 10 to 40 000$ each).

One of these two needs a hand for himself and the second one was there for his wife. It was really nice to hear from these voices that my work wasn´t meaningless. It is my best memory about my project until now even if I get a blue ribbon that day too.

I still have two hopes for my project, to see my hand in universities or FabLabs with students and makers working on it and to meet someone wearing a prosthetic hand based on my design.