15.2-Prototype

Kinematic Analysis

-Plot of System

-Mobility Calculations

The Gruebler Equation to determine the degrees of freedom of the system:

# of links: 6

# of joints: 7

DOF=3(6-1)-2(7)=1

-Kinematic Analysis

-Force Analysis

-Animation

With Velocity:

Without Velocity:

Iteration Documentation

Iteration 1

The above image is our initial idea for our project. This was one of four fingers that was going to be part of a fully functioning hand, although after some discussion and advising, we decided to simplify our original hand design to a mechanism that mimics the in-plane pinching motion of the index finger and thumb. Conceptually, this is a much simpler design to work with and analyze, and we can focus on refining the movements of the joints.

Iteration 2

The second iteration was a continuation of the original design, with a different orientation of the link connections while looking more finger-esque and less claw-like. Although, this design did prove to be nonfunctional in the way we had hoped.

Iteration 3

The third iteration continued with the finger resemblance, with two larger segments, much like a thumb, and using thinner links to connect them to a hypothetical base. This iteration was mostly a rough draft, guiding us to a clearer idea of how we want the links to interact with each other.

Final Iteration and Prototype

The fourth and final iteration was what we based our prototype on. This iteration is the most like a mechanical claw while still having some inspiration from the idea of a finger. After researching many types of links, we settled on a double Chebyshev linkage. This linkage converts rotational motion to roughly linear motion. From the way the link that makes up the tip of the “finger” is connected, it should rotate about the closest joint within a certain limited angle range, or oscillate back and forth. The rest of the links cause the rotation to become somewhat of a linear translation of the link down towards the base.

Bill of Materials