This project is a sub-project of Haifa3D Robotic Hand. In this project, we present the mechanical design of the Oded Hand – a 3D printed robotic hand with five micro-DC motors. The aim of this design is to be low cost, accessible, easy to assemble, robust and lightweight.
The Oded Hand can perform a variety of user-defined hand configurations using an autonomous adaptive grip along with a variety of grip force levels. The mechanical design consists of four fingers with four different tendon-driven mechanisms actuated by four different micro-DC motors, a passive thumb with two discrete positions using two magnets and wrist rotation driven by planetary gears and a DC motor. Each finger is an independent module, hence from a developer point-of-view, you can check new finger designs and change the number of fingers in your hand model. For more details, see the project presentation All five independent micro-DC motors are driven by a microcontroller system which measures the motors’ current state (see our Electronic Design) and communicate via Bluetooth with additional sensors or systems (see our Mobile App).
The design is suitable for users with a below elbow amputation. We welcome any new developers to enhance our design or to use the Oded Hand as a simulator for your new sensors/algorithms/methods that would potentially help users to control their prosthetic hand.
See our detailed Manual, including printing parameters, assembly instruction and images. Notice: some of the images are from our previous version but the current version assembly and functionality can be deduced easily according to the same instructions. The STL files can be found here as a folder or here as a zip file ready to download. The source files (SolidWorks2020) can be sent upon request, while the Parasolid parts can be found here.
To build the Oded Hand you will need a basic knowledge of 3D-printing and an access to a 3D printer.
We use the UP mini 2 printer + ABS / SnapMaker2 + PLA
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Please refer to the user manual before printing the files for printing parameters, recommendation and more.
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Oded Hand parts list:
| Part Name | Quantity | Hand Module | Right/Left Hand |
|---|---|---|---|
| Gear Finger | 3x4 | Finger | Both |
| Gear Finger NR | 1x4 | Finger | Both |
| Proximal Phalange | 1x4 | Finger | Both |
| Middle Phalange | 1x4 | Finger | Both |
| Distal Phalange | 1x4 | Finger | Both |
| Pinion D* (or Pinion) | 1x4 | Finger Driver | Both |
| Pulley Clip | 1x4 | Finger Driver | Both |
| Finger Motor Chassis | 1x4 | Finger Driver | Both |
| Single Pulley | 1x4 | Finger Driver | Both |
| Palm Cover | 1 | Palm | Right** |
| Palm | 1 | Palm | Right** |
| Finger module holder | 1 | Palm | Right** |
| Thumb | 1 | Palm | Right** |
| Planetary Gear | 3 | Wrist | Both |
| Wrist Pinion D* (or Wrist Pinion) | 1 | Wrist | Both |
| Rotator Housing | 1 | Wrist | Right** |
| Rotator Upper Adaptor | 1 | Wrist | Right** |
| Rotator Lower Adaptor | 1 | Wrist | Right** |
| Rotator Base | 1 | Wrist | Both |
| Wrist Cover | 1 | Wrist | Both |
* D-shape is preferable. ** Parts need to be mirrored for left hand model.
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tools and materials list
tools:
- Nippers
- Soldering iron and solder
- Flat file
- Drill (optional)
Materials:
- Common Filament (Ø1.75 [mm])
- Thick filament (Ø2.85 [mm])
- Nylon thread 0.6 diameter[mm]
- Silicon tube (outer diameter 8 [mm])
- 1 Stainless Steel Rod Ø4x30 [mm] (length 29-34[mm] are also optional)
- 2 Magnet N52 Ø6x4
- 5 Hex headless screw M3x4 or M3x5
- 1 Machined Screw and nut M2x8 [mm] (length 8-10[mm] are also optional)
- 6 self-tap Screws M2x8
- 2 Machine screws and nuts M3x40 [mm]
- Electrical Wire for ~0.5 [amp]
- 5 micro metal gear motors – N20 dc motor, 6V, LP or MP (low or middle power), between 100-200 RPM for the fingers (we are using 200 RPM) and 30 RPM for the wrist. For instance, an aliexpress seller.
After you complete the mechanical assembly of the Oded Hand according to the Manual, please refer to the Electronic Design to assemble the PCB. If you have already assembled the mechanical and the electrical parts, you are welcome to check out our Mobile App to refine the controller parameters and to define your favorite hand movements.
This project was done by a group of great people and with the help and guidance of generous organizations.
Mechanical design: Oded Katzman, Shunit Polinsky, Frank Schenk, Avital Dellariccia, SU-PAD company and Taga Product Design Company, Israel.
Users Communication: Haifa 3D – a nonprofit organization that designs and builds hands for free, founded by Yoav Medan and Yacov Malinovich.
Resources: The Technion - Israel Institute of Technology and special thanks to Prof. Alon Wolf and the Biorobotics and Biomechanics Lab.
