Transfer the Load with Winch Challenge - Day 5

Today was the final trial of the challenge. My partner and I had completed the initial requirements last class, so this time, we focused on gaining bonus points. Any team that lifted more than one mass would receive those points. Previously, our robot did not complete more than one cycle due to uneven weight distribution; the robot was top heavy. 

Below is a video of our robot completing two cycles of the challenge. It lifted a total of 400g (200g per mass). 

Final Thoughts 

I had more fun in this challenge than the first one; however, it was a lot more difficult. The robot was different than all the one's we created before, especially since it was not car-based. This time, we had to apply our knowledge of gear ratios in order for the robot to properly function, and we had to conduct multiple calculations.

Performance: As previously mentioned, our robot completed all requirements in order to receive full credit. Throughout the building process, we directed our focus to weight distribution and stability. We added counterweights to various places, allowing the mass to be lifted steadily. If we were to do this challenge again, we would more closely focus on the string that lifted the mass; it kept on slipping, limiting our robot to completing only two cycles.

Improvement and Learning: Thanks to this challenge, I am proud to say that I now understand the concept of "torque", for it is something I never understood before. To put it as my partner did, we also learned a lot about patience; taking apart and rebuilding practically defined our Winch Challenge experience. Because this trial was more successful than the last, I hope that my robot-building skills continue to increase as I move onto the next challenge. 

Transfer the Load with Winch Challenge - Day 4

Last class we completed the challenge! My partner and I fixed the sliding string by adding a second axle where it could loop over. We added a metal Lego hook to the end of the string to allow the string to smoothly return down. We also used the rubber Lego wheels as weights and balances. We noticed that each time we ran the program, the top motor would lean extremely far forward. Originally there were three support axles where it connected to, but we were able to find a location to insert a fourth one, greatly improving its stability. In order to receive full credit for the challenge, we needed to lift one mass up to the table, have the robot change directions while holding the mass, deposit it on a wooden block, and return to the ground. Bonus points would be awarded if the robot could lift multiple masses. We were very close to completing another cycle, but unfortunately it lifted the mass just short of the necessary height. Next class we still have another trial. By that time, we will try to enforce the robot even more, and hopefully receive extra credit.

Transfer the Load with Winch Challenge - Day 3

Design by the end of class

Last class was the first trial day. We were able to successfully balance our robot's systems by using what we learned from the previous unit. In the beginning of the challenge, each team was given two 100 gram masses to help with balancing mass distribution. We connected two long axles opposite to the end where the 200 gram mass was being lifted, and we hung the two 100 gram ones at the far end of the axles. Doing this greatly steadied our robot. As for programming, we were able to find decent power combinations to accommodate our gear ratio. With these two portions completed, our robot was practically set to complete the required actions; however, when put into motion, the string used to lift the mass kept on sliding out of place. Trying to prevent the string from slipping took up  most of our time. Unfortunately, due to lack  we missed our first trial opportunity. Hopefully next class we will be able to test our design.

Final code

Transfer the Load with Winch Challenge - Day 2

NXT Brick used for base

Last class was the second day of robot construction. We mostly worked on the base of the robot, which the two motors would rest on. The base's foundation was the NXT brick to counterbalance the weight of the mass the robot would be lifting. We attached Legos to the brick that acted as legs and axles that acted as a platform. The motors fit perfectly on top of the axle-platform, but the only problem was that it lacked stability, especially when pressure was put against it. We were told that for this challenge, we could only use the provided Legos and string. To further stabilize the motors resting above the structure, we used string to tie it to the base. By next class, we need to test whether or not the string interferes with the robot's movement and functions.

Transfer the Load with Winch Challenge - Day 1

Last class was the first day of the new Lego challenge. We are required to create yet another robot that lifts an object and moves it to another place, but this time, we are using different systems, including gears and pulleys. We are working towards finding an ideal gear ratio that maximizes angular velocity while still having enough force advantage to lift as many weights as possible (within given time limit).