Munitions Manufacturing A Call for Modernization (2002) / Chapter Skim
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Appendix C: Open Modular Architecture Controller
Appendix C: Open Modular Architecture Controller
Pages 158-177
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From page 158... ...
As seen in the diagram below the Melt Pour Operation Consists of the following components: Projectile Component Pre-Heaters - Brings Projectile Components to Proper Temperature Melt Kettle - Prepares TNT Material Pour Machine - Dispenses TNT Material Cooling Bay- Controls Cool Down of Filled Projectile Probe Machine - Inspects TNT Material for Desired Temperature Profile 758
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From page 159... ...
.. -~.., if.,, \/ Figure C- 1 Melt-pour operation The following examination includes additional components that are not seen in the existing diagrams but are necessary to achieve an automated Melt Pour Operation.
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From page 160... ...
While the Pre-Heaters do not need to perform these calculations it is the responsibility of the Pre-Heaters to respond to the temperature- profiles based on these calculations. Me/f Kelf/e The melting portion of the operation involves combining two forms of TNT.
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From page 161... ...
A flow sensor will be included in the automated process allowing for precise real-time control over the pneumatic valve and directly over the material flow rate. The OMAC controller will use the sensor information to precisely contorl material flow to each projectile.
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From page 162... ...
:.:.S '.:,5 ,.,,f,^.~ ' 2 ,,""',,:', , ~ ~5:.:,',.~, ~.~ ~ ~~.~ ~~ ~~ ~ ~~ ~~'~ .. Figure C- 5 Cooling bay
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From page 163... ...
The temperatures can be used to control several upstream parameters: Pre-Heat Oven Temperature · Melt Kettle Temperature · Cooling Bay Profile The OMAC controverts ability to provide an integrated system allows for the closing of control loops throughout the Met-Pour System. /ntegrafec/ Projecti/e Han c//in g System The automation scenarios of the Met-Pour operations are contingent on having an integrated projectile handling system.
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From page 164... ...
The goal of the following examination will be to identify the control scenarios needed to create an autonomous twin screw operation. As seen in the diagram below the twin screw operation consists of the following components: · Material Feed Area - solid powder and solvent · Extruder Barrel - actual mixing area · Die Area - exit area for mixed material · Takeaway area - conveyor belt and indexing table area Figure C- 6 Twin screw operation
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From page 165... ...
The OMAC controller is required to perform the motion control over the screw axis as well as the agitators. The agitators are controller by constant amplitude vibrations under various duty cycles.
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From page 166... ...
The actual conveyor speeds will by set by the process model accounting for the exit pressure from the die and the material characteristics of the propellant. CONTROL REQUIREMENTS The following tables summarize the control requirements for the MeltPour and Twin Screw Operations as well as the entire TIME Program.
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From page 167... ...
Component Control Domain Pre-Heat Ovens Melt Kettle Pour Machine Cooling Bay Description Dual Oven Control Capability Closed Loop Temperature Control Oven Temperature Model Closed Loop Temperature Control Closed Loop Single Axis Motion Control Closed Loop Vibrator Control Melt Process Model Closed Loop Pneumatic Valve Control Pour Process Model Closecl Loop Tem peratu re Control Cooling Bay Process Model Controls Two Commercial Ovens Actual Set Points are determined by process Model Model Parameters · Temperature Loss Model for Each Component Material Delivery Time ~n-process Delays based on material upstream Controls Metal Grid to a profile as dictated by process model. Agitator Control - Speed set by process model.
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From page 168... ...
Valve Control Closed loop Agitator Actual Set Points are determined by Control process Model Extruder Closed Loop Temperature Model set points must be Control maintained in the 4 heating zones in the extruder barrel.
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From page 169... ...
Die and Takeaway Closecl Loop Temperature C~osecl loop temperature control Area Control over the hot and cold zones of the die area. Single axis motion control The process model dictates that temperature set points.
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From page 170... ...
The TIME program requires a true "Open" controls architecture that allows for creation of control loops not originally predicted by the controls developer because of lack of technology or models. As summarized in the preceding tables, the following major features characterize the TIME controller: Model Based Control Closed Loops throughout the Controls Architecture High Speed Deterministic Communications between Facilities Hard Real-Time Capability (Guaranteed Maximum Response Time)
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From page 171... ...
STATE OF COMMERCIAL CONTROLLERS In light of the TIME program controller requirements, a review of the current state of commercial controllers is required. The cost effectiveness of COTS integration technologies has lead to major innovations within the controls community.
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From page 172... ...
These separate PEC and complex motion packages require the controls engineer to use different development environments depending on the control problem. Lack of Integration Between Venclors IEC-61131 has provided standard requirements for the expression of control logic.
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From page 173... ...
DCOM must be examined against the constraints of the TIME program controllers. DCOM was designed for the desktop world.
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From page 174... ...
The TIME project offers a very challenging view of the word "Open" characterized by: . · Support for Moclel based control Ability to close loops throughout the controls architecture · High speed deterministic communications between facilities
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From page 175... ...
Closed Loops throughout the TiME's definition of closing loops is not Controller PEC & Motion constrained to a single control discipline. No commercial controllers allow for closing loops to levels that include changing control laws and interacting with the entire control architecture.
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From page 176... ...
Table C- 4 Tl M E Requirements and OMAC Features TIME Requirement Support for Model Based Control Closed Loops throughout the Controller PLC & Motion High Speed Inter-Facility Deterministic Communications Single Development Paradigm for Models, PLC and Motion Logic Extensibility and Portability Hard Real-Time Support O MAC Feature Introduction of Model Algorithms are allowed throughout the controller independent of whether it involves axis position, 1/0 or calculated variables. OMAC allows for access to all variables within the control system independent of type.
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From page 177... ...
The engineer concentrates on the problem and the OMAC environment makes sure they have access to all data necessary to solve the problem. In short, the OMAC environment allows the controls engineer to concentrate on the controls problems and not the problems of the development environment.
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