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Group 11- ASME Design Competition • Alicia Christie • Desmond Bourgeois • Toddrick Ruff ASME Design Competition Rule Update •Rocks do need to touch receiving area •1 rock in each circle Schematic of Test Course 2 – 1700 pt rocks 1 – 1600 pt 2 - 1500pt 2 – 1000pt Score S = Σ (R*t) +1000P - W - A - 1000T – 5s R = designated rock score t = target multiplier W = Weight of the vehicle in grams A = milliamp-hours available to the device according to the battery labels T = Times device touches border tape s = seconds to complete task, maximum 240 P = bonus for parking vehicle at end of task (1 = parked, 0 = not parked) Decision from Last Presentation 3 – Wheel Design Street Sweeper Mechatronics, Ariel University Center Design Concept rotate move Must be in an equilateral triange configuration for symmetry 3.500 L 2*cos(30)[r+s/2] r 4.000 s r + 2*cos(30)*[r+s/2] = 3.75 in Wheel set distance D = 4r + s : if r = 1 in, s = 1.18 in, D = 5.18 in D*2 + 4 in (box size with guides in back) = 14.36 in with wheels and box touching Max length is 14.5 in Design Concept ? 3.5-r 3.50 d r r 4.00 d 2 4 ( 3.5 r) 2 in Final Design •Wheels are offset with front wheels on inside barrier barrier Idea for body expansion • Switch blades Approximate Extension Length Interim Prototype 3 Wheel Operating Principle Exploded View Assembled View Gear Force Analysis Assumptions Radial Tangential Axial •Const. load with uniform shock •Const. mesh with no backlash •Axial load is negligible •Qv < 5, low pinion velocity < 13m/s •99% reliability •Full-depth teeth with tip loading • Pressure angle 20º •Operating temps < 200º • Teeth form standard AGMA profile Gear Force Analysis Given TP H p 20 deg H .121hp .p 250 rpm TP 3.447 N m TP 2.542 ft lbf Resulting Forces TP wt wr wt tan wresultant wt 229.768 N wr 83.629 N wresultant 244.514 N wt 51.654 lbf wr 18.8 lbf wresultant 54.969 lbf wt dp cos 2 Rock Collector Free Body Diagram 1lb Position #1 • Assumptions – Weight of box = 2lbs – Weight of Front = 7lbs – Tipping will not occur on back wheel ∑M = ∑F*d 3lb 3lb 2lb M T ;WBox d1 cos( ) WFront d 2 cos( ) T 3.5in 1.5in 5.9in 10.225in M = 34.04 lb-in, moment created by rock collector would have to exceed this limit to tip over giving a negative moment Cost Analysis Cost Analysis Current Total: $943.70 Future Plan • FEM Analysis to determine ways to remove material •Amount of motors, gears, other control components •Exact gear placement to minimize motor use •Program control components •Power input and velocity calculations •Exact placement of wheels and expandable body to fit within size requirement •Placement of batteries and motors •Control configuration