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Our plan for producing this robotic hand includes researching the anatomy of the human hand, existing linkage designs for tension-driven robotic hands, experimenting with various linkage designs, software optimization, prototyping, testing, and improvements. We aim to complete our set objective of creating a pure linkage-based hand that can at least grasp some objects. This will likely include a lot of test designing, kinematic simulations, and prototyping. If possible, we would like to perfect the design and functionality of the hand by adding more range of motion and sensor-driven features in the future.
Preliminary Design
Preliminary design of the fingers
We will be referring to the finger joints by their anatomical name. Figure 1 will show what the names of the joints are.
Figure 1: Graph showing and labeling finger joints with their anatomical name.
Crossing 4-bar mechanism from MCP to PIP Joints
Figure 2 shows the planned preliminary design for the mechanism between the MCP and PIP joint, with an initial length. The actual lengths are still to be determined.
Figure 2: Preliminary design of the MCP - PIP crossing 4-bar mechanism
| Link Name | Link Length (mm) |
|---|---|
| L1 | 6.3 |
| L2 | 28.2 |
| L3 | 9.5 |
| L4 | 27.3 |
Crossing 4-bar mechanism from PIP to DIP Joints
Figure 3 shows the planned preliminary design for the mechanism between the PIP and DIP joint, with an initial length. The actual lengths are still to be determined.
Figure 3: Preliminary design of the PIP - DIP crossing 4-bar mechanism
| Link Name | Link Length (mm) |
|---|---|
| L5 | 9.4 |
| L6 | 24.8 |
| L7 | 6.0 |
| L8 | 20.1 |
Various ideas for achieving compliance within the hand.
Figure
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4:
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shows the side profile of the pawm and finger mechanism. This is one potential design where the finger mechanism will close to a percentage of fully grasping then the compliant link will snap the finger close.
Figure
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5: shows another potential configuration where the figure mechanism stays the same without the added compliant part. (4-bar kinematic chain) The palm shown has the linear actuator linked to a dampening kinematic chain that drives the finger mechanism.