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
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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
Tank
Radiator
Filter
Q
Hydraulic
Motors
Relief
Valve
Engine
Reversible
Pump
Check
Valves
Check
Valves
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
D = 0.3m
Fr
• 1 wheel schematic
• Use ½ weight
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)
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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
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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)
Dp
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
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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
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
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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
MATV Project Management Plan
7-Jan-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
27-Jan-10
16-Feb-10
8-Mar-10
28-Mar-10
17-Apr-10
Questions!!!