Total Time: 15 Hours

7/16/2024

8 Hours

I started this project off with a long and highly motivated day of CAD. Inspired by Gypsey Danger and Dragster (another PLANT drum), I made the robot four wheel drive with the weapon direct driven off of a 2822 motor. I also experimented with a swept drum design for this robot, with it coming to a point in the center. I believe that this will help it cut through plastic and it also just generally looks cooler. For the drive system I chose to try out indirect drive off of an N20 motor because it was a very cheap system to make and it allowed me to use a single repeat dual brushless ESC to run both the weapon system and drive system of the robot, as I could reflash one of the channels to run dual brushless with Greenjay firmware. This ended up being cheaper than using a Malenki HV and a seperate weapon ESC, while allowing me to use much higher quality components. For tires I opted to use lego tires, as they were cheap, easy, and had plenty of traction. For the battery I chose to use a 4S 300mah LiHV battery.

This was my sketch of the robot's weapon's side profile. This profile has a 50mm outer diameter and features an asymmetric design to maximize bite. I swept this profile along the helix to create a unique weapon design while still allowing it to be balanced. I also went in and put a pocket in each side of the drum, with a solid center in the middle, to save weight.

I started modelling the frame by making a master sketch which I would then use as the base for rest of the features. Affter a few extrusions and fillets, the robot is starting to take shape. From there I added wheelguards and made space for the drive motors. I also started to think about how the top plate would be mounted. After that, I added the top plate and created a cutout for the weapon motor wires. I then created an assembly file and inserted the motors, wheels, battery, and ESC.

Along with making most of the CAD model, I also started working on the Bill of Materials and weight sheet for this robot, allowing me to check to make sure I was underbudget and underweight.

I ended up not being a fan of the forks in this design, as they looked too fragile and I did not have enough weight for them.

7/17/2024

3 Hours

Today, I redesigned the robot so that it did not have wheel guards, aiming to save weight to allow me to get a fork configuration into weight. However, I ended up not being a fan of the exposed wheels and the fork mounting it would have forced me into. Coincidently I also made a mistake when closing the files when I finished this session and did not save the frame when I meant to not save a different file, so all of the changes made in this version were lost, which was fine since I didn't like most of them anyways.

I also added a few more items to the bill of materials that I had missed previously.

7/18/2024

2 Hours

Today, I redesigned the front of the robot to not have fork mounting and added mating features for the drive motors and some mounting holes for the axles that the wheels sit on.

7/24/2025

2 Hours

Today I made some final changes to the frame(mounting holes that I skipped) and sliced it to get a final weight. This frame will be printed with 2 walls, 2 top layers, and 2 bottom layers, which will hopefully be strong enough while saving plenty of weight.

The robot currently sits right at the weight limit as I have it on my sheet, and I figure that if I need to I can likely save some weight later down the road in the wheel hubs and drive pulleys if I need to.

After this, I worked on shipping this project.