Modeling and Simulation of System
D.K.Chaturvedi
Reader
Faculty of Engineering
Dayalbagh Educational Institute
Agra
Organization
• Basic concepts of system.
• Introduction to modeling and simulation.
• Modeling and Simulation of some real life
systems:
– Parachute
– Aircraft Arrester barrier system
– Aircraft landing control system
What is a system?
• The term system is derived from the Greek
word systema, which means an organized
relationship among functioning units or
components.
• A system is defined to be a collection of
entities, e.g., people or machines, that act
and interact together toward the
accomplishment of some logical end
[Schmidt and Taylor (1970)] .
System
• Three things are necessary to identify a
system:
– System Boundary,
– System Components and
– Interaction or Interdependence of components.
Environment
SYSTEM
C1
INPUT
C3
OUTPUT
C4
Cn
C5
C6
MODEL
• Model is an abstraction (essence) of a real
system. It is a representation of reality.
• A model of a system is a tool to answer
questions about the system without having to do
an experiment.
• Different models can be constructed for different
purposes.
• An abstracted models may be:
– Verbal models (vague)
– Mathematical models (precise).
• The word model is derived from Latin and it’s
meaning is mould or pattern (physical model).
• Modeling is a process of abstraction of a real
system.
Simulation
• Simulation is derived from Latin simulare
which means pretend.
• Simulation is thus an inexpensive and safe
way to experiment with the system model.
• However, the simulation results depends
completely on the quality of the system
model.
Simulation can tell
us things we don’t
already know.
BENEFITS OF USING SIMULATION
• Simulation points out modeler’s own
ignorance and give a Detailed Look at Your
System
• Improve Staff and Equipment Efficiency
• Try Out Many Different Scenarios
 Save Time and Money
 Simulation Improves the Quality of Analysis
 Simulations create virtual Environments
WHEN TO USE SIMULATIONS ?
• Changing one part of your strategy, results in
cascading changes throughout your organization.
• Simulation can help you in gaining the confidence to
make tough choices.
• Many of the opportunities you are evaluating haven’t
been tried before (New Ideas).
• Many of the consequences of your decisions might
only partially be under your control. This makes
decision making messy, but simulation is good at
handling these messes.
• Making mistakes would be expensive and painful
• The decision you are making is complicated and
difficult to think.
Return-on-Investment
Efficiency
(Money)
Effectiveness
(Time)
Risk Reduction
(Environment, Lives)
Simulation makes a real and positive
difference in national military readiness
and national productivity.
•
SIMULATION PROVIDES
Efficiency
* Cost quantification in terms of savings or avoidance.
- Higher mission availability
- Increase operational system availability
- Transportation avoidance
- Reduce / Eliminates expendable costs
- Less procurement & operational costs

Effectiveness
* Positive Contribution that are seldom quantified
- Improved proficiency / performance
- Provide activities otherwise impossible short of combat
- Provides neutral & opposition force
- Greater observation / assessment / analysis capability

Risk Reduction
* Safety
* Environment
* Equipment
- What is the risk?
Risk is the possibility of loss, damage, or any other undesirable event.
- Where is the risk?
Almost any change, good or bad , posses some risk.
- How significant us the risk ?
Once the risk is identified, a model can help you in quantifying it (putting a
price on it). It also help you in deciding whether risk is worth taking.
Model Development
SYSTEM
Purpose
Performance
Measure
Level of
Boundaries
Detail
MODEL
IMPLEMENTATION
Design
Alternatives
Steps in the modeling process
• System Description
• Gather experimental data that describe the system’s
behavior
• Investigate alternative models
• Make the model
• Validate the model
 Show that the model behaves like the physical system
 Simulate something not used in the model’s design
 Perform a sensitivity analysis
•
•
•
•
Integrate with models for other systems
Analyze the performance of the model
Re-evaluate and improve the model
Suggest new experiments for the physical system
Modeling and simulation of
Parachute
 It is the building block of any recovery system.
 The performance characteristics of parachute
must be known for selecting and designing.
 Parachutes are used for paratroopers, recovery
of unmanned aircraft, missiles, ordinance
devices, manned and unmanned space craft
and for speed reduction of landing fighter
aircrafts.
Heat generation in Parachute
• A large amount of heat is generated during power
packing and deployment of parachute.
• Heat developed during packing may be controlled, but it
is uncontrolled when parachute is deployed.
• Heat generated due to interlayer friction and wall-fabrics
friction.
• Canopy is poor conductor of heat and irregular in shape.
• Large temperature gradient is developed in canopy
surface.
• This may cause a major failure in the parachutes.
M&S of Heat generation in
Parachute
 Methodology: System Dynamics Technique
 SDT the cause-effect relationships are
identified among each pair of variables.
 In SDT causal loop diagram and flow
diagram have an important role. These
diagrams offers convenient way to
conceptualize the system.
Causal loop diagram
Wall temp., T
+
Room temp, Ta
+
+ Rate of
- change of wall
- temp.
RT
-
Adiabatic wall temp
Taw
Surface areas,
s1, s2, s3, s4
Temp of environment
Ts
Specific heat of
canopy material, C
Radiation shape factor
FS
+
+
Rate of change of
energy stored by
canopy, RE
+
+
Mass of canopy, M
Energy stored
by canopy, E
Flow diagram
Wall
temp., T
Adiabatic
wall temp
Taw
Rate of change
of wall temp.
RT
Radiation
shape factor
FS
Room temp, Ta
s1, s2, s3, s4
Specific heat of
canopy material, C
Temp of environment
Ts
Mass of canopy, M
Rate of change
of energy stored
by canopy, RE
Energy
stored by
canopy, E
Dynamo Equations
T.k=T.j + dt * RT.jk
RT.kl = (CC.k+L*A*S2 –BB.k – AA.k)/
(M*C)
AA.k=c1*FS*E*S4*(T.k4 – TA4)
BB.k=c1*S3*E*(T.k4 – TA4)
CC.k=H*S1*(Taw – T.k)
E.k=E.j + dt*RE.jk
RE.kl=M*C*RT.kl
Simulation
T
RT
Time, sec.
Modeling and Simulation of Parachute.
M.Tech. Dissertations guided
B.R. Gupta (ADRDE), An innovative approach for
modeling and simulation of parachute inflation and its
performance, 1993.
Bahadur, K. (ADRDE), Modelling and Simulation
Performance Characteristics of Flexible Aerodynamic
Deceleration Device, Dec., 1993.
Work Published
- Chaturvedi, D.K., and Gupta, B.R., Simulation of
Temperature Variation in Parachute Inflation, J. of The
Institution of Engineers (India), AS, Vol. 76, Sept. 1995, pp. 2931.
- Chaturvedi, D.K., and Gupta, B.R., Heat Generation
Modelling During Parachute Packing and Deployment,
National Conference on System Design and Simulation
(SYDSIM), Agra, April 30 – May 2,1992.
- Chaturvedi, D.K., Bahadur, K., and Gupta, B.R., An
Innovative Approach for Predicting the Selected
Performance
Characteristics
of
Aerodynamics
deceleration Device, Proc. Of National Systems Conference
(NSC – 92), pp. 123 – 126, Madras, 1992.
- Chaturvedi, D.K., Gupta, B.R., and Bahadur Kunwer,
Performance Evaluation of Parachute During Inflation,
Proc. Of National Systems Conference (NSC – 94), D.E.I.,
Dayalbagh, pp. 232, Agra, Jan. 14 – 16, 1995.
Aircraft Landing Control System
M.Tech. Dissertations Guided
Mahadev B. Alloli, Intelligent Control System for Aircraft Landing, April
98.
Ramawadh Chauhan, Automatic Aircraft Landing Control System
Using Neural Networks, Dec. 1998,
Published
Chaturvedi, D.K., Ramawadh Chauhan & Kalra, P.K, Applications of
Generalised Neural Network for Aircraft Landing Control System, Int.
J. on Soft Computing, Springer- Verlag, Vol. 6, No. 6, Sept. 2002, pp.
441-448.
Aircraft Arrester Barrier System
M.Tech. Dissertation Guided
R.K. sharma (ADRDE), Performance characteristics of Aircraft Arrester
Barrier System”, 1994
Published
– Chaturvedi, D.K., and Sharma, R.K., An Experimental Study of Initial
Tension of Suspension Strap of Aircraft Arrester Barrier System,
National Systems Conference, PSG College of Technology, Coimbatore,
pp. 474 – 481, Coimbatore, Dec. 14 – 16, 1995.
– Chaturvedi, D.K., and Sharma, R.K., Modelling and Simulation of Force
Generated in Stanchion System of Aircraft Arrester Barrier System,
Int. J. of Modelling, Measurements, and Control, France, B, Vol. 64, No. 2,
1996, pp.33-51.
Aircraft Arrester Barrier System
AABS
• This is installed at the end of
runway for the purpose of
arresting combat aircrafts while
overshooting runway lengths
during aborted takeoff and
emergency landings.
• Various parts of AABS:
–
–
–
–
–
Stanchion system
Energy Absorber System
Tape retrieval system
Tape and suspension system
Electrical systems and their
Control systems
Existing Energy Absorbing
System
• It consists of two velocity sensitive turbine type
rotatory hydraulic energy absorbers.
• It has a housing and a rotor, both consists of
blades.
• Rotor rotates in fluid and due to fluid friction brakes
applied on it.
Housing
Rotor
Problems of Existing Energy
Absorbing System
•There is no control on braking torque of Existing
energy absorbing System.
• The Existing EAS is highly nonlinear in nature. The
initial braking torque is very high but once it starts
rotating, torque reduces to a significant low value.
• For different types of aircrafts (weights) needs
different aircraft arrester barrier systems or modified
energy absorbing system (i.e. different drum
diameters).
•All the energy is wasted in the form of heat.
Proposed Energy Absorber
• To overcome the drawbacks of existing
energy absorbing system and provide
back up to it an Eddy current EAS is
proposed.
• Proposed EAS could be the combination
of existing system and eddy current EAS.
Pe =K Bmax2 f2
Requirements for Eddy current
EAS
• High Voltage and high frequency
Generator for Eddy current Energy
Absorbing System.
• Prime mover for rotating High Voltage
Generator.
• High voltage cables and suitable intelligent
control system.
CONCLUSIONS



Basic Concepts of modeling and simulation.
System Dynamics Technique of Modeling.
Modeling of some defence systems.
-Parachute heat generation modeling
during deployment.
-Aircraft landing control system
-Aircraft arrester barrier system.
Conclusion





Energy absorber system is a crucial and very
important part of Aircraft arrester barrier system. If
there is any problem with this during operation whole
AABS fails .
Hence it is necessary to give some backup to Energy
Absorbing system (EAS).
The Eddy Current EAS along with hydraulic EAS is
proposed.
Eddy current EAS is fully controlled.
The same Aircraft Arrester Barrier System could be
used for different types aircraft (like light weight,
heavy weight, etc.)
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Faculty of Engineering, DEI