MECH 4240 Concept Review Corp 2 Lunar Excavator Anna Holland Kyle Otte Alex Hollis Cody Salmon Han Cho Outline Concept Development Concept Details Mission Objective Final Concept Gantt Chart Drive System Subsystem Concepts Scoop System Decision Matrix Dump System 3 Concepts Analysis Testing Mission Objective Create an autonomous excavator that weighs less than 80 kg can collect and deposit at least 300 kg of lunar regolith within the 15 minute time limit and that will win the 2012 Lunabotics Mining Competition The overall size cannot exceed 0 75 m width x 1 5 m length x 2 m height at the start of the competition However the length and width constraints may be exceeded once the competition starts Gantt Chart Concepts Effectiveness Risk of Failure Speed 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 0 3 2 2 0 0 0 3 1 0 0 0 0 0 0 0 0 0 3 2 1 Cost Drive System 6 Wheels 4 Wheels Tracks Scoop System Bucket with actuator Grader Conveyer Belt Broom and Dust Pan Pull Bucket Auger Dump System Dump hopper Auger Material Fiberglass Aluminum Carbon fiber Strength 0 Total 3 2 2 Weight Complexity Decision Matrix Accomplishes Well Accomplishes Poorly 0 Indifferent Conveyor Failing Tracks Failing Concept Option 1 Drive System 6 Wheel Scoop System Bucket Dump System Auger Disadvantages Hard object could clog the auger Regolith could clump and not be picked up by auger Strong motor needed on the bucket scooping system Concept Option 2 Drive System 6 Wheel Scoop System Bucket Dump System Hopper Disadvantage Strong motor needed on the bucket scooping system Concept Option 3 Drive System 6 Wheel Scoop System Belt with small buckets Dump System Hopper Disadvantages Small buckets take longer to fill Hopper Very complex design Belts are less reliable Final Concept 6 Wheels Regolith Storage Hopper Actuator Controlled Dump System of Entire Storage Hopper Single Large Bucket for Mining Regolith Rotational Joint on Bucket Arm 1 DOF Regolith Transfer Solid Edge Simulation Working Model Simulation Actuators strong enough for max loads Wheels have enough torque Reasonable actuator lengths System within size limitation Max dump angle 55 Drive Subsystem 6 motors to control wheels 6 10 x 4 Polyethylene Wheels Skid steer system Frame Material Fiberglass Tube 1 m x 0 4 m x 0 5 m frame box houses motors Netbook electronics Analysis Testing Required motor torque can be reached with gearing 6 wheels provides enough traction ARGO 6 Wheel System Proof of Concept No suspension Skid steer system Very stable Very powerful Dump Subsystem Max Capacity 150 kg Material Aluminum bottom and front Analysis Testing 7000 N actuator strong enough to lift full load Length of Actuator is reasonable 12 in Scoop Subsystem Max Capacity 17 5 kg 8 6 full scoops 1 full hopper 18 75 small scoops 1 full hopper Blade to cut through top layer Material Aluminum bottom and back Analysis Testing Actuator strong enough to lift full load Length of actuator is reasonable 12 in Arm length sufficient to reach hopper Finite Element Analysis 10 kg in bucket distributed evenly All DOF constrained at end of arms Max Von Mises stress of 29 4 MPa Aluminum bucket brackets Rigid Epoxy Arms Yield Strength of 6061 Aluminum 200 MPa USDA Testing Speed Test Results Weight Added Distance Time Avg Velocity 0 kg 5m 7 0 sec 0 714 m s 95 kg 5m 8 0 sec 0 625 m s 196 kg 5m 10 3 sec 0 485 m s Motor performance not affected Velocity loss mostly due to 4 small wheels ground clearance Issues with battery Netbook housing Electrical System Issues from testing Battery and Netbook housing Loss of battery connection Re Design Incorporate specific housing to prevent battery from disconnecting Protect cushion the Netbook from vibration damage First Cut Economic Analysis Estimated Mass Breakdown Mass Budget Tracking Subsystem Scoop System Drive System Dump System Frame Miscellaneous Total Weight kg Component Bucket Actuator Mechanical Arms Wheel Motor Hopper Actuator Body tubing panels etc Electrical Circuit System Batteries Netbook Cameras Fasteners Mass kg Qty 2 800 1 2 500 2 2 500 1 3 100 6 0 920 6 10 000 1 6 800 1 Mass Total kg 2 800 5 000 2 500 18 600 5 520 10 000 6 800 12 000 1 12 000 0 500 2 700 1 500 0 097 2 500 1 2 1 3 1 0 500 5 400 1 500 0 291 2 500 73 411 Critical Design Review Full failure analysis Concept verification Scaled down mock up Further Testing Aluminum angle test 3 point bending test on fiberglass tubing Moment calculations for arms actuators Finite Element Analysis Fully dimensioned CAD drawings Dissemble old excavator Preserve Electrical Any Questions