It's Alive!

Hey, there, fans of ME 250!

So although our machine is certainly not "alive", we did have some fantastic news coming out of this week--our MCM moves! Our cart and axles are completely assembled including pillowblocks, bushings, and our dual gearbox drive motor to power the front axles. When we connected the dual gearbox to the power source to demonstrate our module to Sei Jin, it actually drove forward (very slowly but powerfully, just as we had intended)! Our machine certainly won't be a speed demon, but hopefully it will be somewhat stealthy and tank-like.

In other news, we also completed our "All Engineering" (AE) assignment this week. We've now finished designing every part of our machine, and we're ready to machine everything starting this week. After our MCM, we actually only had one module remaining--the arm with its driving and winch axles. After some new analysis and changes to our original design, we finally settled on the module setup shown in Figure 1 below. We'll let you know how machining is going next week!

What we have left to do:

-machine all arm PVC parts

-machine axles for arm and winch

-assemble machine and configure planetary gearbox motors

-test machine

Hope you all had a safe and happy Thanksgiving! See you in a week...

Team 42

PS: Interested to see how our schedule has changed? Click here for more information on our current plan!

Figure 1: Completed CAD assembly for All Engineering assignment.

Figure 2: 3 very excited members of Team 42 show off our completed MCM.

Figure 3: Dan's thumb approves of the completed MCM!

Turkey Day Update

Hey there, fans of ME 250!

Almost Thanksgiving, and you know what that means, folks--Team 42 has been hard at work designing and machining our contraption as we get closer and closer to the December 10 deadline. This week, we had lots to take care of: the completion of 3 machined parts as well as planning and prep for the MCM demonstration and All Engineering (AE) assignments. It tires us out just thinking about it!

For our 3 machined parts, we chose our axles (because we have different types for the front and rear they counted as 2 parts) and our wooden cart base. The base was machined using the laser cutter, while the axles were fabricated using turning and band sawing methods. All the parts came out well and within our specified tolerances, and we were really happy with the end result. Stay tuned for some sweet photos once we get the whole MCM assembled for this week--we wouldn't want to ruin the surprise!

In addition to working on the physical construction of our MCM, we've also begun designing our other module--the cart arm--this week. We plan to use PVC piping to create an outer and inner arm which can then be controlled using the winch attached to a planetary gearbox. The other planetary gearbox will be used to drive the arm itself, which will rotate on a "square axle" (it's awesome, we promise). As can be seen in Figure 1 below, we've slightly reworked and expanded upon our original proposed design, but we're confident that all of these changes will ultimately be for the better.

So, fans, after our presentations on Tuesday it looks like we'll have a few days off, with the Design Expo just on the horizon. YES WE CAN.

That's all for now... safe travels and catch you on the flip side!

-Team 42

Figure 1: Re-working of arm mechanism for "All Engineering" assignment.

Figure 2: Adam works to keep the motor parts in order while assembling the second planetary gearbox.

Weekly Update

Hey there, fans of ME 250!

So it's been quite a week in the world of ME 250--we've officially started production! After completing our motor lab assignments in addition to our Most Critical Module (MCM) preparation last week, we finally felt comfortable enough to begin manufacturing components for our MCM. Unfortunately for us, the part that we began with--the metal cart plate cut by the waterjet cutter--was misaligned while being machined, leading to center-of-mass and alignment issues that we felt just couldn't be overcome.


So what did we do in this time of crisis? Went back to the drawing board! After some discussion, we decided to scrap the metal plate (Get it? Scrap metal?) and construct a wooden cart base instead. This base could be bigger than the metal one (due to the fact that we were supplied with a larger piece of wood in our kit) and could also be manufactured easily using the laser cutter in the machine shop. After this change in design, we re-did the CAD drawings for the new larger cart base and plan to cut it early on Monday morning (see Figure 1 below).


In addition, the motor lab finally supplied us with enough information to finalize the pillow block designs (the motor heights were required before the bearing and bushing positions could be finalized), and we'll be completing the machining of these parts tomorrow morning as well. It's going to be a big day for Team 42!

Anyway, off to go and study for the big exam. Wish us luck!

-Team 42

Figure 1: Redesigned cart with wooden base.

Figure 2: Ilya and Adam working hard at the motor lab.

ME 250-Blogging Week 2!

Hey, everyone!

So this was an interesting week in the world of ME 250--we spent lots of time together working on our MCM project (hooray for Thursday nights at the Ugli!). After hours of toil and trouble (see pictures below), we came up with what we thought were final designs for our cart, axles, and pillow blocks.

As may or may not be visible in the CAD drawing below (Figure 2), there are 36 separate screw holes to anchor the three types of pillow blocks on to the cart base--a lot of dimensions to include on a small type-A mechanical drawing! After we re-dimension our cart base (as well as the pillow blocks and one type of axle), we'll be ready to start machining this week. We've created a bill of materials and a manufacturing plan for this module, and we'll hopefully have a firm grasp on the manufacturing before exam week comes next week (time flies, eh?).

Before we start manufacturing, however, we'll have to buy some additional materials, most notably a 1/4 aluminum rod with more precise tolerances to better fit in the supplied wheels. Characterizing and measuring the motors is also a major goal for this week--we want to make sure that all alignments will work before any parts are manufactured.

If you have any questions, comments, or concerns about our progress, feel free to email us at me250group42@umich.edu. We welcome suggestions!

Thanks all for now, folks... see you in a week!

-Team 42

Figure 1: Team member Dan Cox prepares some calculations.

Figure 2: CAD of full cart Most Critical Module (MCM) without wheels or driving mechanisms.