DIMEC
CONFERENZA
INCOSEdi ITALIA
SU SYSTEMS ENGINEERING
Dipartimento
Meccanica
CIISE 2014 – Roma, 24 – 25 Novembre 2014
Identifying the smartness of a mechatronic
coiler through the ‘System Engineering’
Eugenio Brusa, Ambra Calà
Dept. Mechanical & Aerospace Engineering
Politecnico
di Torino,
CIISE
2014 – Rome, Italy
– E. Brusa,Italy
A. Calà – Politecnico di Torino
1
DIMEC
Dipartimento di Meccanica
Model – Based Systems Engineering and
Design of heavy machines and industrial equipments
 Design of large equipments and heavy machines usually
involves a fairly high level of complexity because of :
 the number of operations performed to complete the
process
 the presence of several subsystems and components
 the need of a continuous monitoring and control
 the high demand of safety, reliability and performance
 the size of the system
 the number of coupling effects present (mechanical,
thermal, electromagnetic …)
 Designers are currently prone to resort to two main
approaches:
 ‘Mechatronics’ to apply some artificial intelligence or
‘smartness’
 ‘Systems Engineering’ to face and mastering
complexity
CIISE 2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino
DIMEC
Dipartimento di Meccanica
The real contents of ‘smartness’ ?
 Very often defining some suitable smart function to be applied to the system is rather
difficult although we know from the literature several attributes which might drive this activity
(Skelton – Bradley – Meirovitch – van Eyik …), but a straight application is sometimes hard …
Attribute
Selectivity
Self – diagnosis
Description
Capability of assessing the system properties depending on the working
conditions
Existence of intrinsic parameters which detect a failure condition
Self – tuning
Sensitivity
Skill of performing an internal calibration
Relation between cause and effect in the coupling (i.e. linear, nonlinear)
Shape – ability
Capability of modifying the system shape for different needs
Self – recovery
Possibility of reaching a saturation without failures
Simplicity
Simplicity of the energy conversion mechanisms, of the configuration
Self – repair
Skill of recover a stable and working condition after a saturation
Stability
Standby skills
Survivability
Switch – ability
All the possible stabilities of the system operation
Possibility of keeping a defined configuration
Capability of avoiding failure modes
Possibility of operating at different levels of energy if the architecture of
the system allows
CIISE 2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino
DIMEC
Dipartimento di Meccanica
The role of the ‘Systems Engineering’
 The MBSE approach allows some main and powerful actions in this field:
 completing the system requirements by introducing some smart / adaptive / active
function
 identifying and localizing the smart functions by allocating those additional
requirements
 allows performing a trade–off of architectures, electromechanical coupling phenomena
 detecting some physical ‘hidden actor’ (present in physical material system never in
sofware engineering) but often origin of some misunderstanding in design.
through two challenging issues of the SE application: drawing the diagrams of the system
model and inter-operating those with the physical models …
CIISE 2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino
DIMEC
Dipartimento di Meccanica
An experience within ‘Smart Steelmaking’
 To clarify those issues a practical test case will be
proposed concerning the shaping and storing of
coils from steel rods outcoming from the rolling mill
production line.
System
Super – system
Billets
Rolling
CIISE 2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino
Finishing (coiling and delivery)
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Dipartimento di Meccanica
System : coiler unit
The rolling mill
The rod
The system
The storage
The operator
The monitoring and
emergency system
The powerline
The building / environment
 Coiler is a sub-system of the whole plant and is located at the end of the product line. It
needs to be carefully synchronized with the production line to avoid any accidental stop in
delivery. It stops the rod within a certain distance from the cutting edge, it changes the shape
from rod to a coil and it stores the coil.
 The quantum of motion associated to the rod translation (up to 150 m/min, i.e 2.5 m/s)
is transformed into a rotational one.
 The rod is incoming into a rotating tubular shaft, connected to a so–called laying head and it
is delivered to the storage unit.
CIISE 2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino
DIMEC
Dipartimento di Meccanica
Customer’s needs, feeling, … dreams
It is a matters of evidence that :
The laying head and its bearings suffer a severe wear of material
The rotor balancing is very critical because of the irregular distribution of rod
mass within the head, especially at the beginning and at the end of each rod
segment.
Innovation motivates the manufacturer to:
■ design a modular system, composed by a coiler system and a storage unit
■ assure a precise synchronization of the rotor angular speed and the speed
of the production line
■ reduce wear by either changing or avoiding lubrication, but assuring the
system safety against the risk of fire
■ actively control any abrupt variation of the working condition (suggested active
magnetic bearings with small gap and electromagnetic compatibility assured)
■ submit this unit to the overall supervision of the main plant control system
CIISE 2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino
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SE : Smartness allocation through the diagrams [Use case]
The question …?
USE CASE DIAGRAM ACCORDING TO THE CUSTOMER
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Dipartimento di Meccanica
SE : Smartness allocation through the diagrams [Use case]
Power seems to be fed without any
Power supply
feeds
(“hidden query from the system but:
actor” in -it has to be checked first and
case of
-eventually substituted by a back-up
disfunction)
service
The powerline
V diagram
Conflict ?
Acquires data
monitored and
checks
Imposes stops
Maintains, tests
and calibrates
(“hidden actors” in
case of disfunction)
Requires
suspension
and rotation
only receives
a sensor might measure the
Requires shaping
amount of rod processed
and delivery
The platform is never asked to
provide mechanical support or neutral
potential reference (ground) in electric
circuits, but in case of disfunction it
applies some unsuitable action
The storage unit usually only receives
the rod but it could even measure the
amount of rod processed, thus
reducing the number of sensors
applied to the rotor.
Provides ‘grounding’
Additional remarks
Operator and Emergency system
have simultaneously access to stop
the system but
-a hierarchy is required and
-emergency system not only stops but
also records the monitored signatures
The plant
CIISE 2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino platform
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Dipartimento di Meccanica
SE : Smartness allocation through the diagrams [States]
Smart link
The so – called rotor ‘nulling’ operation
at standstill could be automatically
performed by the system (by comparing
currents and positions of the rotor shaft)
and monitored by the supervision control
system
CIISE 2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino
DIMEC
Dipartimento di Meccanica
SE : Smartness allocation through the diagrams [Activities]
Sensors
1) Condition associated to the
platform
2) Condition associated to the
risk of fire
1
2
3
3) Condition associated to the
safety
status
Smart links
- Need of sensors
- Connection to the control
systetm unit
- Warning and monitoring
CIISE 2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino
DIMEC
Dipartimento di Meccanica
SE : Smartness
allocation
through the
diagrams
[Sequences]
Smart links
- Landing of rotor has to be
safe: back – up in power
feeding is required and
automatyically activated
upon warning about the lack
of main power feeding
- A direct measurement of
coils stored by the storage
unit can allow stopping the
delivery from the laying
head
CIISE 2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino
DIMEC
Dipartimento di Meccanica
SE : Suggestions related to the block diagrams
Signature
monitoring
requires a defined
resolution
Compatibility
of electric
connections
with power
line standards
Canned rotor to
avoid contact
between rod and
inductances
Switching amplifier to
decrease dissipation
Safe landing on
additional bushings
Reliability of
mechanical
connections
against
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2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino
Detection of the real
neutral phase
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Requirements improvement
Customer needs and preliminary requirements
Requirement diagrams
CIISE 2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino
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Additional
requirements,
towards the
smartness
Examples
SR007 : Wear (CN): The system shall
reduce the wear of materials in operation.
SR007-1 : Wear (TN): The system shall be
suspended without direct contact
SR007-1-1: Wear (SN): Contactless
suspension through active magnetic
bearings shall control and stabilize the
system dynamics in operation.
…
SR012 : Safety against fire (CN): The
system shall prevent any risk of fire.
SR012-1 : Safety against fire (TN): The
system shall use special lubricants to
prevent any risk of fire.
SR012-2 : Safety against fire (TN): The
system shall prevent any abrupt
dissipation which might induce a severe
increasing of temperature.
SR026 : Switch-ability (SN): The system
shall be operated by resorting to different
levels of power, i.e. by switching from
one power set to another as in power
amplifiers working in switching mode.
CIISE 2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino
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Dipartimento di Meccanica
CIISE 2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino
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Mechatronics vs. Systems Engineering: results
CIISE 2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino
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Dipartimento di Meccanica
Testing, verification, validation
Tests:
- nulling
- levitation at
standstill
- critical speed
crossing
- stable
supercritical
rotation
- unbalance
response when
rod feeding
- safe landing
- rod stopping
- storage
saturation …
CIISE 2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino
DIMEC
Dipartimento di Meccanica
Customer’s satisfaction about the SE implementation
Severe wear of
bearings and material,
run-outs, unbalancing
Difficult
synchronization
The rolling mill
The rod
The system
Imperfect
detection of
processed rod
The storage
The operator
The monitoring and
emergency system
Fire prevention
The powerline
The building / environment
Problems with lack
of power
CIISE 2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino
Problems with
mechanical and
electric grounding
DIMEC
Dipartimento di Meccanica
Conclusion
 Application of the SE to the specific context of mechatronics for large industrial
equipment still needs some assessment in terms of conventional
interpretation of diagrams, functions, components.
 Requirements verification, refinement and assessment is greatly improved and
somehow ‘smartness’ contents are clarified and requirements better allocated.
 In the test case customer’s satisfaction was reached.
 In terms of methodology for design a very good matching between the
mechatronic approach and rules and the results of Systems Engineering was
found.
 Challenging issues are : updating the standards in mechatronics by fruitfully
using this approach – vs – assessing the tools of Systems Engineering for the
mechatronics context.
CIISE 2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino
DIMEC
Dipartimento di Meccanica
Thank You for Your kind attention !
prof. Eugenio Brusa , ing. Ambra Calà
Politecnico di Torino
Dept. Mechanical & Aerospace Engineering
[email protected] ; [email protected]
CIISE 2014 – Rome, Italy – E. Brusa, A. Calà – Politecnico di Torino