“Besides black art, there is only automation
and mechanization.”
Federico Garcia Lorca
The Gantry Automation Project Overview
The
Objectives
How it was
programed
Our
Approach
The Final
Result
The Logic
Codes
Rhys Porter , Joseph Eric Roy, Anthony Moody
The Objectives
To Solve a Puzzle Using Automation
V0
Green
V1
V2
V3
V4
H0
H1
H2
H3
H4
Amber
Red
The Objectives
To Solve a Puzzle Using Automation
V0
Green
V1
V2
V3
V4
H0
H1
H2
H3
H4
Amber
Red
The Objectives
To Solve a Puzzle Using Automation
V0
Green
V1
V2
V3
V4
H0
H1
H2
H3
H4
Amber
Red
The Objectives
The Puzzle Solved State
V0
Green
V1
V2
V3
V4
H0
H1
H2
H3
H4
Amber
Red
Our Approach
Understand the task, then
Define the sequences
How it’s going to be done
V0
Green
V1
V2
V3
V4
H0
H1
H2
H3
H4
Amber
Red
Stack all the disks together
V0
Green
V1
V2
V3
V4
H0
H1
H2
H3
H4
Amber
Red
Measure the disks
V0
Green
V1
V2
V3
V4
H0
H1
H2
H3
H4
Amber
Red
Till the puzzle is solved
V0
Green
V1
V2
V3
V4
H0
H1
H2
H3
H4
Amber
Red
“Controlling complexity is the essence of computer programming”
(Brian Kernigham)
Hierarchical State Machine Design
S1 :
Dormant
Lights
S100-199
S2 :
Starting
Lights
S200-299
S3 :
Recover
Actions
S300-349
Lights
S350-399
S4 :
E-Stopped
S5 :
Running
Lights
S400-499
Stacking
S10001499
Sorting
S15001999
Lights
S350-399
Resource Allocation
Name
Main State
Sub-States
State Memory
Other Memory
Timers
Primary
–
S0-9
M0.0-3.7
M4.0-9.7
T0-9
Powerup
S0
–
–
–
–
Dormant
S1
S100-199
M10.0-13.7
M14.0-19.7
T10-19
Starting
S2
S200-299
M20.0-23.7
M24.0-29.7
T20-29
Recover
S3
S300-349
M30.0-33.7
M34.0-34.7
T30-34
Recover+Run Lights
S3
S350-399
M35.0-38.7
M39.0-39.7
T35-39
E-Stop
S4
S400-499
M40.0-43.7
M44.0-49.7
T40-49
Running: Stacking
S5
S1000-1499
M100.0-103.7
M104.0-149.7
T100-149
Running: Sorting
S5
S1500-S1999
M150.0-M153.7
M140.0-199.7
T150-199
Recover+Run Lights
S5
S350-399
M35.0-38.7
M39.0-39.7
T35-39
Interaction of Main States
Interaction of Main States (Simplified)
Benefits of a Hierarchical State Machine
•
Minimises code duplication
•
•
Easy to follow debugging
•
•
Ability to see states the PLC is in at any point
Any sub-state bugs are contained
•
•
Eg “Go Home” memory bit to return to HO,VO
Use of function calls and sub-state re-initialisation and clean up
Mutated sub-state behaviour based on “Flag” memory bits set
•
Eg Different Lighting behaviours or stacking columns
Machines
“If you don’t trust them, then program them”
(Joseph Eric Roy)
Gantry Simulation
Physical Constraints
Speed
• Simulation
• Suction
•
Time
• Over extension
•
Switch location
• S7-300 PLC
• TIA portal software
•
Stacking State
Recovery State