MATV Memorial University All Terrain Vehicle Team members Jonathan Cole Trevor Dwyer Fabio Faragalli

Project Overview Design an autonomous amphibious vehicle able to navigate rough terrain Allow for the attachment of components for navigation, automation, and various future endeavors Improve upon the design of existing competitors vehicles that have inherent design weaknesses

Project Deliverables Design and fabrication of one complete hydraulically powered wheel assembly Design and fabricate a closed hydraulic system to support driven wheels Design and fabricate robust offroad suspension for vehicle Design and fabricate amphibious platform to support vehicle automation equipment and payload

Design Specifications 6 wheel vehicle/platform Hydraulically driven Amphibious Must have enough torque to climb a vertical wall 50 lbs pay load Less than 48” wide 12-14” ground clearance Weight less than 300 lbs At least 2 cubic feet cargo space 24 hour autonomy Attains speed up to 30 km/hr

Hydraulic System Motor, Pump & Engine Sizing Example Specifications: Powered by 6 hydraulic wheel motors One pump per side, powering 3 hydraulic wheel motors each - in series Gas powered internal combustion engine, governed at 3600rpm used to run pumps Employs a closed loop, bi-directional hydraulic transmission (reversible pumps)

System Diagram Q Tank Radiator Filter Hydraulic Motors Relief Valve Engine Check Valves Check Valves Reversible Pump

Sizing Assumptions 2 front wheels have enough torque to lift ½ the weight up a vertical wall 3000psi operating pressure Hydraulic motors in series – equal pressure drop MATV Weight 300lbs Wheel diameter 0.3m Efficiencies all assumed η = 0.9 Max speed 30 km/h Engine governed at 3600rpm

Required Wheel Torque Fg = (300lbs)(1/2 weight)(1kg/2.2lbs)(9.81m/s^2) 1 wheel schematic Use ½ weight D = 0.3m Fr Fg 30° Fg = (300lbs)(1/2 weight)(1kg/2.2lbs)(9.81m/s^2) Fr = (Fg)(Sin30 °) Tr = (Fr)(0.3m) Tr = 50.2 N·m

Sizing Motor Displacement 1000psi (per motor) Tr = (Dm)(P)(ηmm) Dm = (50.2 N·m) / (6.89x10^6 N/m^2)(0.9) Dm = 8.1x10^-6 m^3/rad Dm = 3.1 in^3/rev

Sizing Motor Flowrate Vmax = (30km/h)(1000m/km)(1h/3600s) V = (ωm)(π)(0.3m) ωm = 8.84 rev/s Qm = (ωm)(Dp) / (ηvm) Qm = 4.9x10^-4 m^3/s Qm = 29.5 L/min

Sizing Pump Displacement Qp = Qm (Series) – Pump flowrate Qp = (ωp)(Dp) / (ηvp) Dp = (4.9x10-4 m^3/s) / (3600 rev/min)(1min/60sec)(0.9) Dp = 9.1x10^-6 m^3/rev Dp = 9.1 cm^3/rev Dp = 0.55 in^3/rev

Hydraulic pump specifications Pump type 3070 Nominal Delivery: 32 L/min (29.5 L/min Required) Displacement: 21.33 cm3/ rev (9.1 cm3/ rev Required) Maximum Continuous Pressure 3000 Psi Speed at Maximum Continuous Pressure 3000 rpm

Engine Sizing Rolling Resistance Assume 10% of operating pressure (300psi) Tp = (9.1x10^-6 m^3/rev)(1 rev/2π rad)(2.068x10^6 N/m^3) / (0.9) Tp = 3.33 N·m Engine Power Power = (Tp)(3600 rev/min)(1min/60sec)(2π rad/1 rev) Power = 1255W Power = 1.7 HP Engine runs 2 pumps Power = 3.4 HP 300psi Dp

Selected Engine Specifications Air-cooled, 4-Stroke, OHV, single cylinder Displacement: 163 cm3 (9.9 cu in) Net horse power output: 3.6kW (4.8HP) at 3,600 rpm Net torque:10.3 Nm (7.6 lbs ft) at 2,500 rpm

Selected Engine Specifications Starting system: Electric Starter Oil Capacity: 0.6 liter (0.63 US qt) Dry weight: 13.0 kg (28.7 lbs) Dimensions: 12.0 in x 13.4 in x 12.5 in Fuel tank capacity: 3.1 liter (3.3 US qt) Requires 1.26 Qt/h fuel

Required Fuel Reserves Engine requires 1.26 Qt/h 24h Automation R = (24h)(1.26 Qt/h)(0.946352 L/Qt) R = 28.6 L Design for 32 L (10% reserve) Modified tank required

Suspension Double A-arm suspension chosen Upper a-arm shock mount chosen More clearance for hydraulic motors Allows for maximum suspension travel and ground clearance in offroad environments

Existing Competition Frontline Robotics Foster Miller

Gantt Chart

Questions!!!