MATV Memorial All Terrain Vehicle

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MATV Memorial All Terrain Vehicle Powered By Docstoc
					    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
                        Tank


                                                 Radiator




                      Filter

                 Q
                                                                     Hydraulic
                                                                      Motors


                                        Relief
Engine                                  Valve




                               Check                        Check
         Reversible            Valves                       Valves
          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
                             • 1 wheel schematic
                  D = 0.3m
                             • Use ½ weight
             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)
                                                  300psi
                  Dp

• 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
 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
                                  MATV 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!!!

				
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posted:4/20/2011
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