09.2 - Initial Prototype

Figure 1. Initial Construction of Prototype

In the beginning stages of the project, we needed to build a functional prototype that shows working proof of concept by displaying the manual powered full range of motion of the mechanisms for the autonomous fishing rod.  As seen through the analysis and iterations of the fishing rod, we were able to build a prototype that displays the casting in 3 planes of motion. After building the prototype, we were able to identify any issues needed to be resolved in future design iterations.  

Video 1. Initial Demonstration of Prototype

Iteration of Initial Design 

Casting Mechanism Design 

Iterations between the original design of the casting mechanism include the changing of link 3 to have a slot for the connector rectangle, which connects the casting and positional adjustment mechanisms. When laser cutting the parts, we had iterations for the links due difficulty in assembly because of lengths and diameters of holes.

Figure 2. Initial Path Output of Prototype    Figure 3. Initial CAD of Casting Mechanism   Figure 4. Modified Path Output of Prototype                                              

Figure 5. Final CAD of Casting Mechanism

Output Link

The output link initially had a slider but after testing and analysis, it was concluded that a bearing connection was more effective. 

Figure 6. Iteration 2 of Output Link                                                            Figure 7. Iteration 1 of Output Link

Ground Link 

The slot for the slider in the ground link had to be adjusted to connect to the position adjustment mechanism. The slot had to be wide enough to fit the output link of the position adjustment mechanism and the connector rectangle. 

Figure 8. Ground Link Dimensions

Figure 9. CAD of Ground Link

Link 3 

Link 3 also had to be adjusted to connect to the position adjustment mechanism. It stays at a fixed angle during motion, so the angle was determined using the geometry of the casting mechanism and a slot was added at the corresponding angle for the connector rectangle. 

 Figure 11. Iteration 1 Link 3

Figure 10. Iteration 2 Link 3                    

Connector Rectangle

This rectangle was used to achieve 3D motion by connecting the position adjustment mechanism (XY plane) with the casting mechanism (ZY plane) while maintaining the angle of link 3. The casting mechanism link 3 had a rectangular slot at a 45° to be able to attached to the positional adjustment mechanism ground link perpendicularly.

Figure 12. CAD of Connector Rectangle

Final Casting Mechanism 

The final design shows the results of iteration. The ground link and link 3 were adjusted to connect to the position adjustment mechanism and the design iteration of link 4 (output link) with a bearing was chosen for the final prototype. 

Figure 13. Connector Rectangle in Housing

Positional Adjustment Mechanism

Original design, using a linear actuator as input:

Figure 14. Initial Design Sketch: Linear Input

First iteration of rotational input:

Figure 15. Initial Design Sketch: Rotational Input

Final CAD of Prototype (Connection between our two mechanisms not pictured, connector rectangle):

Figure 16. Final CAD of Prototype

Bill of Materials

Most of the parts needed for this project are provided by the RMD class or can be purchased at TIW. There are two items that will need to purchased for the fishing rod, the fishing wire and a linear actuator. In our initial brainstorm, we were considering using the linear actuator to translate between the two planes of motion for the design. However, during the prototype phase, we were trying to find a solution before purchasing the linear actuator. 

Laser Cut Components:

• Positional Adjustment Mechanism (slider-crank)
• Casting Mechanism (5 links)
• Connector Rectangle
• Spacers
• Bases

Electronic Components:

• Linear Actuator
• 360 Degree Servo
• Wires
• Arduino
• Power Supply
• Button

Stock Components:

• Fishing Wire
• 6mm Bearings 
• 6mm Stainless Steel Shaft
• Nuts
• Bolts

Figure 17. Bill of Purchased Materials