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 – 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 45° slope 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(+) 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 in^3/rev. Fixed motor flowrate 51 L/min. Variable pump displacement (Max) 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

Solidworks Model

Weight Estimate

Steps Forward

Questions?