Hello my name is Jordan Yamada and
this will be my engineer's journal and documentation for the class intro to
engineering design. Today we were assigned group and I was teamed up with
Alison Lanzi another student in the class.
So far I've looked at the challenge
which is to design and build a car using a mouse trap spring as a mechanical
source of energy. The way I see it, since I'm on the RPI Formula Hybrid Racing
team and have worked a bit with race car dynamic, getting the energy from
the spring to the wheels of the car is the most important thing. Doing some research I've found that to do
this most simple designs use line of some sort to wind around an axle. Then as the trap is released and the string is tensioned the line unwraps and transfers
the energy to the axle and thus the wheels. To extend the amount of travel of
the spring they suggest adding a longer lever arm which pulls out more line.
One idea that I had was to make the
actual axle that was connected the spring, directly, or through a gear
ratio, to drive the back wheels. This would emulate pull back windup toy cars. I
don't have much experience with the springs or the mouse trap itself so I’m not
certain the ability of me to implement that design. Also seeing as though I
might not have enough time to really get my head around it, it might be more trouble
than it’s worth. Another
thing that this system has either going for or against it is since the spring
is always directly connected to the axle, when the spring runs out the travel
the spring will stop the car. This is will either make it have a braking system which is great when we need to stop at a certain mark, or the travel will be so
short that the car can make many revolutions without a huge gear.
Another idea I had was adjustability.
The Idea isn't flushed out yet but maybe trying to make certain components out
of threaded rod would be great for fine tuning, such as attaching the wheels
(e.g. 2 nuts on a bolt) for a wheel alignment.
Lastly I was also thinking about
the wheels themselves. I really don't like the cds and hobby type wheels seen
in some designs. One because of the low co-efficient of friction means that energy
isn't getting the wheels, and because they seem flimsy. I was envisioning
something more like Lego wheels with rubber tires for grip. I made a mock up to see how they interacted with the ground and it seem to fit my needs. Also another thing
might be wheel tow in, which would make the car self-correct straighter but
might also make it more prone to friction.
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| Random Frame with Wheels to Better Understand Dynamics |
In any case I think this little
brainstorming session was good and that I can maybe start mocking up a table
of some sort to see what are the pros and cons of each idea. Also getting the
material would be a big advantage because then I can actually experiment and measure
some of the materials so I can start doing CADing of my ideas to show to my
partner and the teachers.
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| Sketches in Notebook |
