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Project MATV Presentation #2. Jonathan Cole Fabio Faragalli Trevor Dwyer. March 2, 2010. Outline. Original Design Issues Limitations Improvement Opportunities System Regression Analysis Lessons Learned Governing Relations System Limits Re-design Components Solidworks Model
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Project MATVPresentation #2 Jonathan Cole Fabio Faragalli Trevor Dwyer March 2, 2010
Outline • Original Design • Issues • Limitations • Improvement Opportunities • System Regression Analysis • Lessons Learned • Governing Relations • System Limits • Re-design • Components • Solidworks Model • Weight Estimate • Steps Forward
Issues • Weight • Spec: 300 lbs with a payload of 50 lbs • Actual: 600+ lbs total • Large weight of wheel motors, suspension and fuel • Cost • Cost estimate ~$10,000 • Motors $720 US per motor ($4200+ total) • Tandem pump $1000+
Limitations • Operating Pressures • 2000 psi for entire hydraulic system • Motor limited • Motors in series • 1/3 operating pressure drop per motor • Wheel Motor Availability • Required physical properties of motor • Parker TJ0080 • Could not sustain operating pressure of pump
Improvement Opportunities • Suspension Design • Track width of double A arm suspension • Ground clearance & width potential of swing-arm suspension • Driven System • Weight of wheel motor driven hydraulic system • Weight & cost savings of hydraulic/chain driven system
System Regression Analysis • Required HP dependent only on weight. • Regardless of operating pressure. • Limit of 5.5HP engine is 500lb @ 45° slope (650lb @ 30°). • Required pump displacement and flow rate highly dependent on operating pressure. • Transmission (pump/motor) can handle 4500psi intermittent and 3000psi continuous. • This translates to 1000lb(+) capacity @ 3000psi. • Tire diameter only affects gear ratio. • Required torque at wheels dependent on gear ratio. • Engine governed at 3600rpm, transmission Max 4000rpm.
Drivetrain Components • Honda GX200 • 5.5Hp (4.1kW) at 3600rpm • 9.1 lbs·ft (12.4 Nm) at 2,500 rpm • Dimensions 12.6 in x 14.8 in x 13.2 in • Dry weight of 16.0 kg (35.3 lbs)
Sauer-Danfoss 15 Series In-line Transmission • Operating Pressure: 3000psi (cont.), 4500psi (int.). • Fixed motor displacement 0.913 in^3/rev. • Fixed motor flowrate 51 L/min. • Variable pump displacement (Max) 0.913 in^3/rev. • Variable pump flowrate (Max) 51 L/min. • Motor output torque 135 lbf·in (11.25lb·ft) per 1000psi. • Dimensions 13.3 in x 8.0 in x 6.5 in. • Dry weight of 16.5 kg (37 lbs).
New Design • Swing-arm Suspension • Coilover Shock Design • Chain Drive • Custom Axles/Hubs • 80/20 Inner Frame • Aluminum Outer Body