Most Critical Module Completion / Top Bot Engineering

Assembled module w/o motor and ramp components

During this week, our team successfully completed our Most Critical Module, which is now fully-functional.  We were able to clearly demonstrate our module for our MS8 assignment just how it would be used in the actual game, by mounting it in the slot and running it.  After hooking up the module to a battery pack, we were able to repeatedly launch our ramming arm over and over, each time having it function just as we intended.  We were also able to demonstrate the functionality of the ball-collecting components by dropping several balls on top of the module and watching them fall into the opening as intended.  All in all, we did great on our MS8 assignment, as well as with our engineering of our other modules.

Early assembly of module

There are a few modifications that can be made to the main module.  Our most critical modification will be ensuring that all balls which roll down the ramp will make it into our slot.  We have noticed slight problems with alignment,  but we are going to test and determine which type of modification (such as adding a small supporting wall) will be the best in any situation.  Other modifications include overall alignments that could increase the ramming force of the arm, help guarantee successful scoring of balls, and improve assembly and disassembly during competition.





In addition, our team has created our engineering designs for our top bot, including the CAD models, drawings, manufacturing plans, and bill of materials.  We have even already acquired all of the materials we will be using.  It is now simply a matter of machining the top bot, and we should have the overall machining of our entire Slotbot completed by the end of this week.

Assembly and necessary components 

Most Critical Module Nearly Complete

Module in progress

This week has been quite a busy week in the machine shop, and so far we have nearly completed our Most Critical Module.  One major feature are the side frames, and they look excellent.  We used the laser cutter to cut the frames out of stock acrylic sheets, and then the drill press to countersink the holes to allow for a flush finish when the module is complete.  This allows our frames to be held together with metal spacers (as seen in the photo to the right), and the final screws to be flush with the outside, allowing the module to easily slide and fit within the arena slot.  A lot of work has been done on both the mill and lathe as well.




As for milling, the majority of our rectangular and square metal stock pieces have been milled for the actual ram rod components, and look very clean.  Great care has gone into making sure the parts we make are well-machined as well as have precise tolerances, ensuring all our pieces will fit properly and tight when we assemble the completed module.

Mounting disks to hold side frame to arena walls

Our lathe work has been great as well.  We have successfully made quite a handful of spacers to be used for bracing the frames, and the mounting disks which will actually hold the frames to the inside of the arena walls have been successfully machined.  We have been carefully measuring all of our pieces to make sure they are correct, and have also tested the pieces out by doing some trial mounting within the actual arena.  As of now, it seems our most critical module is coming together nicely, and should be completed within the next few days.

Motor Lab & Manufacturing Progress

This week our team made significant progress with manufacturing components for our Most Critical Module, as well as completing our most recent assignment: the Motor Lab.

Two identical planetary gear configurations

Assembled 400:1 gear set without motor attached

The Motor Lab consisted of assembling a planetary gearbox set with a 25:1 and a 400:1 gear ratio, and testing the performance of each configuration separately.  We initially tested the motor alone using a constant voltage from a DC power supply unit, and took measurements of rpm and current, using a tachometer and readings from the power supply unit.  We then used a planetary gearbox assembly to create a 25:1 gear ratio, attached it to the motor, and ran more performance tests with the new configuration.  After this, we coupled the output shaft of the motor to an aluminum rod, with a Kevlar thread attached to the rod.  Weights were tied to the end of the thread, and as the shaft and rod rotated, the thread wrapped around the rod, pulling the weights.  This allowed us to test the assembly under different loads.  We used metal nuts as weights, and varied the amount of weight for different tests.  Once we finished testing our 25:1 gear ratio assembly, we repeated all of our tests using a 400:1 gear ratio.  Our team also designed a reinforced "Winch" mechanism that has a frame which helps support the loads placed on the mechanism while in use, and will likely be used in our actual module.

In addition to our Motor Lab, our team has made significant progress with the manufacturing of our Most Critical Module.  We have successfully cut out one of our side frames from a quarter-inch acrylic plate using the laser cutter.  Although we originally intended to use aluminum for our side frame, we used acrylic due to our constraints on budget and resources, since it is an effective alternate material and should hold up quite well while in use. Also, it looks really cool with our module (the transparent frame shows all the inner workings of our module).  We have also nearly machined our mounting disks; all that remains is separating the machined stock into individual disks.  We are currently in the process of cutting the other side frame and machining our rod components and frame spacers.

Motor Lab Photos:

The basic Motor Lab setup

Measuring the output speed of the motor without gears attached

"Winch" Mechanism:

Winch mechanism will pull a wire upwards

Side view of Winch - the wire will wrap around inner shaft

Most Critical Module/MS6 Progress

Full Assembly of "Most Critical Module"

This week Team Boss focused greatly on preparing and analyzing the engineering behind our Most Critical Module, the Ram Rod.  We created a complete CAD model and drawings of the module, developed a step-by-step manufacturing plan for our machining process, created a bill of materials, reviewed this information with our GSI, and even picked up a few stock pieces of metal that will be used for the module.  We were also trained on how to use waterjet and laser cutters, which will be vital for our machining process.



The CAD model allowed our team to not only see how our module will look when we fully machine and assembly it, but also revealed any important design aspects we may have overlooked or should be more aware of, such as issues with dimensioning or mounting.  However, the module is now fully worked out and should be fairly straightforward to machine and assemble, especially now that we have written a comprehensive manufacturing plan to be used while machining the module.

Example of "Manufacturing Plan" for a single component

The manufacturing plan outlines the overall process of machining, as well as important factors such as tool types and speeds.  We also created a bill of materials containing information on the cost to acquire materials for our module, and even managed to gather some of the materials from one of our suppliers, Alro Steel, to be used in the module.  At the end of the week, we reviewed all of this information with our GSI for our MS6 assignment, which went smoothly overall.

"Side Frame" - Will be cut with a waterjet cutter