2. ● Engineering and construction of a Pick and Place Robot
● Picks up, repositions, and releases 12.7mm diameter steel spheres
● Sorts spheres from 9 base base plate locations to 2 drop hole locations
● Uses serially stacked axis configuration
● Provides motion in 2 Rotary Axes using 2 stepper motors and one servo
● Servo motor raises and lowers steel spheres within the gripper assembly
● Controlled with Arduino that is mounted on the base plate
● Normally open micro switches on both axes to identify home position
● Automated sorting function controlled by Arduino Code that can perform
any sorting sequence given
Overview - Pick and Place Robot
6. Sphere Base Overview
● Constructed with ABS plastic by
means of rapid prototyping
● Raised 3 inches off the working
surface
● Supported by (6) 3 inch long
carbon fiber hollow tubes
● (.04’’ thick)
● Total weight is 63g
7. Sphere Base Analysis
Deflection and Factor of Safety
● Length(L) = 183mm
● Width(a) = 11.2mm
● Height(b) = 3 mm
● 2nd Moment of Area(Ix) = 2.52x10^(-
11) m^4
● Yield Strength of ABS = 20.7 MPA
● Modulus of Elasticity of ABS = 1379
MPA
● Total Deflection = .5mm
● Factor of Safety = 20
8. Sphere Base Analysis
Deflection and Failure Analysis
● Length(L)= 38.1 mm
● Width(a)=11.2 mm
● Height(b) = 3mm
● 2nd Moment of Area(Ix) = 2.52x10^(-11) m^4
● Yield Strength of ABS = 20.7 MPA
● Modulus of Elasticity of ABS = 1379 MPA
● Bending Stress/2 = Max Shear = 49264.3 N/m^2
● Tresca failure yields a FS=40 with b=3 mm
● Deflection = 8.9x10^(-6) m
9. Sphere Base Analysis
● Stress Analysis of
Base using Inventor
Static Frame Analysis
● Max Displacement is
.2837 mm
● Scaled for Visual
Appearance
● Factor of safety is 15
10. Drive Base
Overview
● Constructed using 6061
Aluminum
● Provides support for both
rotary axes
● Provisions for motors
● Total mass 125g
11. Rotary Axes Overview
● Constructed using
Aluminum channel
● Connected using pin
and bearing
configuration
● 210 mm overall arm
lengths
● Total arm mass of 185
grams
13. Rotary Axis 1 Overview
Components
● 210 mm C-channel arm
● NEMA 17 Stepper
Motor and gearing
● 30 RPM Max Speed
● Pin and Bearings
● Microswitch
● Total weight of above
listed components-712g
18. Rotary Axis 2
Rotary axis 1 Rotary axis 2 Gripper Assembly Control
Green Pink Yellow Blue
19. Rotary Axis 2
Components
● 210 mm aluminum
channel
● Stepper motor with
belt and drive gears
● Pin and bearings
● Microswitch
● Total weight is
452.4g
20. Rotary Axis 2
Deflection and Failure Analysis
● Weight of the arm 2= 166.8 grams
● Point load of Gripper= 47.7 grams
● Moment of arm 2 = .0803 N*m
● Ix=80742 mm^4
● E=68.9 GPa
● Arm 2 Deflection= .000327 mm
● Factor of safety=580
21. Rotary Axis 2
Motor Selection
● Nema 17 motor size
● 400 steps/rev
● Torque - 22.7 oz-in
● Weight - 220 grams
● Max Speed 100 RPM
● Current - .6 A
● Gear Ratio - 1.5:1
● Resolution - .6 degrees/step
● Drive Pulley - 10 tooth
● Shaft Pulley - 15 tooth
23. Gripper Assembly
Total weight: 48 grams
Rack Specs.
● Length - 1.5”
● Pitch - 48P
● Teeth - 22 total
Gear Specs.
● Pitch - 48P
● Teeth - 22 total
● 1 full rotation = 1.5” movement in Z
direction
24. Gripper Assembly
Components
● Weight of magnetic ring - .141g
● Dimension of ring - 1/8"od x 1/16"id x1/8"thick
● Pull of magnetic ring - .53lb (8.5oz)
● Required torque is 8.5 oz-in
Motor Specs
● HS-81 Micro Servo
● Torque of motor - 42 oz-in @5V
● Speed of motor - .09 sec/60° at no load @5V
● Weight of motor - 16.6g
27. Control
● Provides control signals for rotary axes and
gripper subsystems
● Will run using 120V from the wall
● Will be programmed so the sequence of ball
placement can be easily reconfigured
● Fully automated process including a homing
sequence
28. Control
Code Structure
● Arms will be homed to a set location using micro switches
● Program will wait on the power button to be pressed to start
● Program will be initiated after the homing sequence
● 2 arrays
o 1 containing coordinates of each location from the home location
o 1 containing the given order of ball placement
● Operations will be looped to calculate the difference between the previous
location and the next location determining the needed movement of each
arm
● After 18 steps program will end
30. System Overview Motion
One step of motion of motor 1
● Resolution of motor 1: .6 degrees = .0104 radians
● A(x) = L1*cos(.0104) + L2*sin(.0104)
● A(y)= L1*sin(.0104) + L2*sin(.0104)
● A(x) = .02 mm
● A(y) = 3.59 mm
One step of motion of motor 2
● Resolution of motor 1: .6 degrees = .0104 radians
● A(x) = L1*cos(0) + L2*sin(.0104)
● A(y)= L1*sin(0) + L2*sin(.0104)
● A(x)= .01 mm
● A(y) = 1.795 mm
31. System Overview - Homing
Axis Homing Sequence
● Each microswitch will be wired to 5V power
● Motor 1 takes 1 step
● Arduino program checks for voltage to A1 input
● If voltage is greater than .1V then movement of motor 1
stops
● Repeat steps for motor 2
● Once robot is homed program will wait for power button
to start the sorting sequence
32. Uncertainty Analysis
Combined PAP system
uncertainty to hole A on base plate
Parameters
● Arm lengths
● Stepper motor resolution
● Arm angle with respect to
horizontal
● Deflection of base
● Gripper gear backlash
● Drive gear backlash
33. Use of rapid prototyping
● 3 integral parts of PAP Robot will be rapid prototyped
● Cost estimate from http://www.redeyeondemand.com/
34. Mechanism Manufacturability - Base
● Sphere Base will be Rapid Prototyped using ABS
● The carbon fiber arrows will be bought and cut to length, threaded inserts will be use to mount to
sphere base
● Aluminum sheet will be cut NEEDS MORE
37. Mechanism Manufacturability - Gripper Assembly
Bill Of Material
● The rack guide will be rapid prototyped using ABS plastic
● The endeffector guide will be rapid prototyped using ABS plastic
