5.6 - Conclusions and Future Work

Results:

Overall, our robot was able to successfully climb a vertical rope without the need for human assistance. We even found that our mechanisms allowed the robot to traverse a horizontally or diagonally oriented rope. We were successfully able to control the force that the robot applied to the rope through the slider clamp and rope cleat mechanisms to ensure our robot does not slide down the rope at any point throughout the revolution of L2.

Lessons Learned:

Our prototype attempted to prevent the robot from sliding down the rope by looping the rope around pins within the linkages and relying on friction to keep the rope in place. This somewhat worked for our lighweight prototype, but adding the motor and battery to our final version made it so that the robot was too heavy to rely on the frictional forces alone. Our solution to this was to implement the slider crank clamp and rope cleat mechanisms to hold the rope in place as the robot ascends the rope.

We also ran into problems with the motor we ordered not having enough torque to lift the full weight of the robot. To solve this problem, we used a more powerful brushless motor in addition to an ESC and controller/receiver. This new motor had more than enough torque to lift the weight of the robot, and also allowed us to change the speed at which the robot climbs the rope.

Potential Improvements:

A useful application for this robot, as mentioned in our proposal, would be to have the robot carry a load as it ascends the rope. This would be useful to industries like mining or construction because materials could be transported vertically without requiring humans to do any work. Currently, our robot can support its own weight (including the motor and battery mounted on the robot) as it ascends the rope, and we estimate it could carry an additional pound of weight, given the capabilities of the motor. However, improving upon this design by using a more powerful motor and stronger links would allow the robot to carry more weight with it as it ascends the rope.

Another potential improvement would be combining the slider crank clamp and rope cleat mechanism so that the robot can climb and descend the rope. Combining these into one mechanism used on both L1 and L4 would allow our robot to function in the same way as it descends the rope. A different motor would also be needed that can change direction without needing any rewiring.

Tips for future groups:

• If purchasing a motor, make an estimate of how much torque your mechanism will require before purchasing a motor. We didn’t account for adding extra weight when purchasing our motor which lead to replacing the motor.

• If your mechanism requires intermittent motion, consider using a cam-follower design. Our cam follower mechanism worked great for solving our problem with our robot sliding down the rope.

• Take advantage of TIW’s resources. Besides electronic components, all parts of our robot were either cut from 1/4” acrylic or 3D printed with PLA. If your components need to be very strong, however, ordering parts may be the way to go.

Acknowledgements:

We would like to thank Dr. Symmank along with TA’s Connor Hennig and Mila Wetz for their feedback during our proposal and the weekly check-ins, helping us stay on track to ensure we were able to complete the project on time.