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Lessons Learned

• The most important lessons learned.® Budgets should always be closely monitored and even then they tend to be

adjusted and changed® Be quick to react to changing requirements® The best engineers never get attached to designs, they can scrap and finish a

project no matter the issues and set back are part of the norm® The problem is never fully finished

– I constantly wanted to fix problems but had to limit myself to getting the project to a stable point, there is always an issue that can be better but sometimes you have to cut your losses

® Even if you are not the sole lead of a project it is never a bad idea to push other to achieve the set goals, it’s a team project

® It pays to ask other for help, suspension systems are not easy finding individuals to help you with ideas pay off ten fold

® Trust your gut, people may tell you what the “norm” is for a certain application, but do research, why is that the “norm”. In some situations (like mine) it didn’t make sense so I questioned it and formulated a new set of ideas

® Have good problem solving skills, I came in with exceptional mechanical skills, from welding to rebuilding small electronics, and you never know when those will come in handy

® Always stay curious, sometimes the best ideas come from just looking at old ideas

® Lastly, don’t ever rule out a possibility till its been tried, sometimes the ‘dumbest” ideas can pay off

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M.A.R.S.U.P.I.A.L. Mechanical Improvements

• Problems® Leading Incline is too steep® Overall height may be too high

– Raised CG® Self Leveling issues® Horizontal spring to stiff® Air shocks cant handle the cold® Reverse direction of tensioning® Track friction

– Too high inside– Too low outside

® Size of lower idler wheels

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Leading Incline/Overall Height

~67 Deg

• Remedies® Lower leading wheels® Lower overall height

• Benefits® Aids climbing over objects

– Allows for ease of the first idler wheel to travel up and over

® Greater speed when traversing obstacles

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Self Leveling

• Cause® Air spring are constant force meaning they are always in equilibrium

• Remedies to existing® First try was to add a spring between rod end and shock

– Springs were not strong enough and were fully compressed® Next try is applying large coil spring over entire shock® Increased spring constant and added spring compressive length

• Benefits® Maintains parallel plane to ground

• Remedies for new system® Added motor inside main Christie

– Ability to actively move CG

• Benefits® Actively adjust vehicle baseline® Actively adjust CG when needed

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Air Spring Problems

• Lower tension in horizontal spring

• Potentially revert from tension springs to compression

• Manage environmental concerns® Encase the air shock in sealed container

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Direction of Tensioning

• W-style active tensioners currently

• Two up force tensioners on the outside® Reduces wrap on motors® Using torsion for upforce

– If too much slack in belt can cause tensioners to flip forwards

• Remedies® M-Style with vertical forces applied

– Gives more wrap on the drive wheels– Removes possible over rotation of clock springs

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Track Friction

• Full PVC track, steel banded® Double sided with guiding feature

– Thought was to be able to dig into the ground and stair ledges ® PVC had largest friction constant, however this is inside and outside,

requiring more than necessary torque to drive

• Possible Remedies® Add nylon facing on inside® Rethink double sided and instead use higher coeff backing® Can have machining done to the backing easily for custom profiles

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Possible Backings