1 badger gate interegr 160 team amit professor john murphy s.a. amit nimunkar client mark novak
TRANSCRIPT
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Badger Gate
INTEREGR 160Team Amit
Professor John MurphyS.A. Amit NimunkarClient Mark Novak
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About AgrAbility
Mark Novak, a BSE professor at UW-Madison is an outreach specialist for AgrAbility
AgrAbility is a federally funded program with the goal of aiding disabled farmers so they can continue production.
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Problem Statement Our goal is to design a prototype of
an automated livestock gate. The gate must be remotely operated to allow a disabled farmer to stay in the vehicle while the gate opens and closes. It must securely latch in order to serve the primary purpose of keeping all livestock inside the pen. It must also be safe, inexpensive, and reliable
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Brainstorming Two-way Winch
System Powered by a
motorized spool to wind cables attached to the gate.
Electronic Actuator An electronic arm
extends and retracts to push and pull the gate.
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Brainstorming Motorized Wheel
A remote operated wheel drives the gate open.
Motor and Chain A motor rotates a
gear which opens a gate by spinning a chain.
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Evaluation Criteria
Safety Cost Efficiency Reliability Ease of use Installation Maintenance
Opens Manually
Space/size
Power Required
Locks securely
Remote compatible
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Evaluation
Motor and Chain requires a new mounting and difficult installation.
The motorized wheel would be too unreliable.
A decision matrix and a group vote was used to pick a final design.
The winch system was chosen as the final design.
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Final Design
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Model Construction
The basic model was a plywood base, with square, 2x2 fence posts, wire fencing, and a ¾ inch diameter PVC pipe, 2’ by 1’ gate. Eye hooks constituted the hinges, and a plastic wheel can mounted to the end of the gate.
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Pulley System We had several
different ideas for use as the pulley system.
Tensioners were needed to pick up slack in excess cable as the motor rotated.
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Pulley System Solution Utilizes a spring loaded
tube to keep pressure on the cable and take up the slack produced when the gate is opened.
Uses 2 tubes of different diameters that can slide over one another with a spring on the inside.
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Motor and Pulleys
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16-Foot Gate Scaled Calculations Amount of power required to open the gate
is approximately 20 watts. Voltage varies depending on the motor
rating Only 11 watts should have been needed Motor efficiency was calculated into the formula
as error. Wire: Steel cable, rated 480-500 lbs Pulley arms: Wood or steel Other materials can be found on our parts
list.
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Servo-Operated Latch
Powered by servo motor
When power is applied, latch opens
1.25 V DC Operated via
joystick: pushing up opens latch
Closed
Open
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Latch Construction Constructed of
Grade 304 Stainless Steel
Servo contained in waterproof housing
Impervious to water Able to withstand
large forces Will not rust or
freeze
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Latch
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Strengths and Weaknesses
+ The system can be universally mounted on preexisting gates.
+ The gate is able to swing both into and out of the pen.
+ Opens gate quickly.+ Can be opened
manually if system should fail.
- Requires more installation.
- Length of pulley arms and cables take up more space.
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Cost Report Estimated Price List for 1/8 Scale Prototype Gate
Sail winch servo motor $53.95
50 lb. test fishing line $(4.00)
Two-Channel remote with reciever and servo
$39.99
PVC $8.25
Miscellaneous (clamps, bungees, springs, pulleys)
$12.00
Total $118.19
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Cost Report Estimated Price List for Full Scale Gate
½ H.P. Motor $60.00
25ft. 3/32” Nylon coated steel cable $21.15
Two-Channel remote with reciever and servo
$39.99
Steel Bar $60.00
Miscellaneous (clamps, bungees, springs, pulleys)
$60.00
Total $241.14
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Video Demo
Gate Video Demo
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Questions
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Calculations Summary Torque data: Torque= Force*Distance= abs(F)*abs(d)*sin(θ) “Theta”= the angle between the moment arm and the
direction of the force. T=F*d*cos(α) “Alpha”=the complementary angle to the gate Torque conversion: 1.27 Newton meter≈ 180 ounce
inches The motor will exert 183 ounce inches of torque on
the prototype gate. Derived formula used for initial torque:
T=0.10667(tension) Newton meters Wire should be able to withstand above 20
Newtons/4.5 lbs of instantaneous tension
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Calculations Summary Gate speed data: Angular velocity= ω= 2π/1.4 radians per second: Motor
speed Diameter of spool= 1.5 inch Tangential Velocity of spool= (1.5)(π/1.4) inches per second D= v*t= (.75)(2π/1.4)(time) D/(π(1.5))= # of turns of spool D= ((7.5)^2+(6)^2)^(1/2) Minimum Time= D/V≈2 to 2.50 seconds for the gate to open Closing the gate should take approximately the same time The calculations for the gate speed are accurate within less
than a second. The scaled up gate will have to move somewhat slower.
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Calculations Summary Gate Power: Kinetic Rotational Energy formula: K= (1/2)Iω^2 Derived formula for rotational inertia of gate (model and
scaled up): I= (1/3)mL^2 L= length of moment arm and m= mass of gate K= (1/6)mV^2 V= L*ω= velocity of gate≈ 4π/2.25 inches per second Mass of scaled down gate≈ 1.00 Kg K= (1/6)(1.00kg)(((π/2)/2.00)^2)((2ft)(1/3.25))= 0.0389
joules of kinetic energy for the prototype gate Power= Work/Time Work= Δ Kinetic Energy= K(f)- K(i)= 0.0389 joules- 0 Theoretical Power after assumption of 50% error: 0.039
Watts as a maximum. Rating of servo motor (from catalogue): 0.0384 to 0.048