MicroTrac Drive Module Rubric

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1	The purpose of this document is to describe the features that are desired, or required of the MicroTrac drive module. This Rubric describes requirements for a sub-urban use case. This usecase is based on the imagined living situation and requirements of Andrew Spina.
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6	User Key:	Ben
7		Feature	Importance of Feature	Detailed Explanation	Variables and Constraints	Acceptance Criterion
8	Safety
9		Limited Pinch Points
10		Low risk of tipping		This is an integration requirement for the tool as a whole.	Low down weight?	I have used one of these and there is a danger of getting the bucket stuck and flinging the whole chassis up, catapulting the operator over the front to the bucket area. More of a hazard then sideways tipping, which shouldn't be a problem.
11		Breaking must be reliable
12		Part failures shouldn't be dangerous		If a part breaks (like a wheel going flat) the operator or other nearby people should be safe.
13	Movement
14		Top Speed			Find a good motor max rpm to drive wheel diameter ratio	A fast walking speed?	4-5 mph?
15		Turning Radius			Skid steer = good turning radius.	Can spin on a point in thoery. A track drive would rip up the ground when doing this however.
16		Multi-Terrain		MicroTrac must drive acceptably on the following surfaces: Grass, Dirt, asphalt, concrete, shallow mud.
17		Gentle Traversal		Driving across and turning on a surface must not harm the surface beyond the specified amount.
18		Water resistance		It may be worth sealing the bottom half from working in mud or water.	This could be incorperated in the chassis
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21	Fabrication
22		Few highly skilled operations
23		Component based design		High modularity allows simple maintanence and improvement of constituent modules without complete redesign.
24		Favor inexepensive materials
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30	Integration
31		Quick attach to MicroTrac		The drive module must attach to MicroTrack (I'm not sure which part) within the specified time.	A rear tow hitch with a rear standing platform could be a conflict and a safety issue.
32		Modular drive		A modular switch between tracks and four rubber pneumatic wheels	Ground level drive wheel would be needed for this to be an easy switch. 2wd?	I think this should be a option when fabricating, not a switchable feature. To begin with at least.	A FWD skid steer loader would not be to bad for front end bucket work. Good weight distribution and should be tested IMO.
33		Customisable front attachments	High	Need to be able to make dozer, screening, bucket attachments and anything else the owner wants to fabricate for himself	A standard connecting system. Additional ram mount points on arms?	I would say stay pretty closely to the dingo/kanga latching system
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36	Dimensions
37		Weight		Prefer lighter weight. This effects when MicroTrac will mark surfaces.	The lighter it is the less it can counterweight for bucket weight, the less it can grip = the less it can tow/pull/doze	I don't suggest skimping on the structure weight, and see how it performs in prototyping. I was actually thinking of a removable rear counterweight to make excavation more effective.
38		Width		Must fit through the average residential gate (apprix 3 foot wide)	Power cube is 26 inches wide. This leaves 5-6 inches for each track width and side walls. Doable.
39		Height		The operator should have a clear view over MicroTrac.
40		Depth
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43	Maintanence
44		Frequency		Long lasting (and few) disposable parts are preferable.
45		Complexity		Simple maintanence is preferred
46		Ubiquity		All non-permanent parts must be replaceable.
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48	Cage
49		Must contain a Power Cube		Power Cube is 26x26x26 inches
50		Pedestool controls
51		Standing platform		For an operator to stand on the rear and be able to see the front attachment clearly.	Flatform size to fit a large mans foot. Grippy surface.	15x26 inch platform, checkerplate overlay?
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