We are planning on having a shop day this weekend to start building the steel shell. Plasma cutting will make it easy, but we have to decide the best and most efficient way to split the armor so that it is easily removable, but not a weakness. We are also going to design some custom 3D printed wheels and mount treads on them.
While the drive system is a major part of robot combat, it wouldn't be combat if there weren't any weapons. Our robot design utilizes an undercutter disk, which is a large disk that spins very close to the ground. Lots of physics goes into designing the weapon, such as kinetic energy equations and center of mass. Thankfully, we have modern Engineering Software to help us with that. Solidworks allows us to find the center of mass of an object that is designed in CAD. This is important, even if the center of mass is slightly off of the center of rotation there will be violent vibrations. The result can give some very interesting looking designs. For example, our weapon disk has a very odd shape, with four cutouts of various size around the disk. Despite this oddity, the center of the mass is directly in the point of rotation. Thanks to Solidworks, we are sure our weapon will spin up smoothly!
Savvy observers may have noticed that budget team is utilizing a traditional twelve-volt lead acid battery. While newer, lighter, lithium batteries would usually be a great, go to solution; cost is the highest priority on budget team. The size of this robot requires that the battery store at least ten amp hours and be able to output very high currents in small bursts. While LiPo batteries can output tremendous currents, the cost of a LiPo with that high a capacity would cost hundreds of dollars. Lead acids, despite being rather heavy, are able to deliver a tremendous amount of power for only one-tenth the cost of similarly sized LiPo battery.