Upload
gwendolyn-jenkins
View
221
Download
0
Tags:
Embed Size (px)
Citation preview
MATVMATVMemorial UniversityMemorial UniversityAll Terrain VehicleAll Terrain Vehicle
Team membersTeam membersJonathan Cole Jonathan Cole
Trevor DwyerTrevor Dwyer
Fabio FaragalliFabio Faragalli
Project OverviewProject 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 DeliverablesProject 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 SpecificationsDesign 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 Hydraulic System Motor, Pump & Engine Sizing Example& Engine Sizing Example
• 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)
Specifications:Specifications:
System DiagramSystem Diagram
Hydraulic Motors
Tank
Radiator
Filter
ReliefValve
CheckValvesReversible
Pump
Engine
CheckValves
Q
Sizing AssumptionsSizing 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 TorqueRequired Wheel Torque
• Fg = (300lbs)(1/2 weight)(1kg/2.2lbs)(9.81m/s^2)• Fr = (Fg)(Sin30 °)• Tr = (Fr)(0.3m)
• Tr = 50.2 N·m
30°
Fr
Fg
D = 0.3m• 1 wheel schematic• Use ½ weight
Sizing Motor DisplacementSizing Motor Displacement
• 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
1000psi (per motor)
Sizing Motor FlowrateSizing 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 DisplacementSizing 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 specificationsHydraulic 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 SizingEngine 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
Dp300psi
Selected Engine SpecificationsSelected 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 SpecificationsSelected 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 ReservesRequired 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 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 CompetitionExisting Competition
Frontline Robotics
Foster Miller
Gantt ChartGantt ChartMATV Project Management Plan
7-Jan-10 27-Jan-10 16-Feb-10 8-Mar-10 28-Mar-10 17-Apr-10
Kickoff Meeting
Webpage Design
Research
Project Presentation 1
System Sizing
Component Selection
Design
Mini Report 1
Parts Ordering
Project Presentation 2
Fabrication
Mini Report 2
Testing
Final Presentation
Final Report
Questions!!!