COMM 1 Nataliya Mulyar Laci Posta Coupling Of Multidisciplinary Models.
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Transcript of COMM 1 Nataliya Mulyar Laci Posta Coupling Of Multidisciplinary Models.
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COMM
Nataliya Mulyar
Laci Posta
Coupling Of Multidisciplinary Models
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Outline
• Introduction: COMM within Bode-RC• Rose-RT• Simulink• Rose-RT and Matlab/Simulink: how to
couple?• State-of-affairs in COMM
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Boderc Project
• Consequences of design decisions can be predicted as early as possible
• System-level decisions can be analyzed
• Trade-offs can be made between functions, price, performance, etc.
Universiteit Twente
Goal: improve multi-disciplinary system design, i.e. combining mechanics, electronics and informatics, such that
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The COMM project
• COMM = Coupling of Multidisciplinary Models• 9- month duo OOTI final project• Started on 1st of December 2003
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Problem Description
Sequential development long development cycle
Parallel development lack of communication btw.disciplines
incorrect assumptions problems during
integration late time-to-market
Possible solution: simulate an embedded system in its intended environment
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COMM Project
The problem of
Coupling of models from different disciplines (M, E, I)
Affects The development of real-time embedded systems
The MCT Is a tool that couples two tools widely used for modeling of software and physical components respectively
That • Helps to detect potential problems earlier• Shortens development time (if used properly)• Provides communication means between multiple disciplines
Focuses on design of Multidisciplinary Coupling Tool (MCT)
Business Case
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Concrete Goals
• Explore possibilities of coupling of tools used in MD modeling – Use Rose-RT and Matlab/Simulink as a concrete case
for coupling
• Get better understanding of coupling: – relation simulation-reality– the notion of time in multidisciplinary modeling
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Simulation
Simulation contains a set of models of one or more dynamical systems and the interaction between those systems and their environment (Jim Ledin).
Simulation advances through time and solves the equations for all models at each point in time.
Model is a physical, mathematical, or other logical
representation of a system/process.
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Simulation
Two basic representation methods of simulation models: The discrete event simulation, where time
is moving forward from one change of state to the next
The time step simulation, where time is divided into intervals
Time step
t1 t2 t3 t4 …
event 3event 2event 1
t1 t2 t3
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Real vs. Simulated
Target system
Simulated system environment
HW
Rose-RT SW
model
Matlab/Simulink physical model
MCT
SW
Discrete Discrete and/or
continuous
Hybrid
Simulate the real-time behavior of the embedded system
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Case Study
Motor Control Loop Model
Set-point generator
Controller Motor Encoder
+
Criteria for case-study selection:
1) Low level of model complexity
2) Multidisciplinary aspect: SW + HW components
3) Interaction btw. SW and HW components
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Mapping on Tools
Motor Control Loop Model
Matlab/ Simulink
Set-point generator
Controller Motor Encoder
+
Rose-RT
Centralized Software Control
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Mapping on Tools
Motor Control Loop Model
Matlab/ Simulink
Set-point generator
Controller Motor Encoder+
Rose-RT
Distributed Software Control
Decision 1: select Distributed Software Control
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Computing resources
1 PC or 2 PC’s?
Rose-RT and Matlab/Simulink
Rose-RT Matlab/Simulink
Decision 2: use a single PC for simulation
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Outline
• Introduction: COMM within Bode-RC• Rose-RT• Simulink• Rose-RT and Matlab/Simulink: how to
couple?• State-of-affairs in COMM
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What is Rose-RT?
Software development environment for: • Creating UML models using the elements and diagrams
defined in the UML • Generating complete code implementations for those models • Executing, testing and debugging models
Uses the extensibility features of the UML for real-time
reactive system development
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Rose-RT from inside
• Stereotypes (special form) of class – Capsules • Template of active objects – Protocols • Template of ports
Environment
Capsule
portS1
S2
Ports: created and destroyed along with their capsule
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Active objects
Encapsulationshell
Ports
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Capsule: Behavior• Optional hierarchical state machine (signal handler with
run-to-completion semantics)
S1
S2 S3
S1
S2
S1
transitionS1toS2: {int x; x = 0; p2.send(s1); p3.send(s2); … };
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Traffic Lights example
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Timing in Rose-RTGoal: Understand the notion of time in multidisciplinary modeling
initialize
InitialInitial
worktimeouttimeout timeout2timeout2
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Timing in Rose-RT
• Time in Rose-RT is strongly connected with the system clock
• Precision is dependent on the granularity of the OS
• Accuracy is not guaranteed
• Timing in Rose-RT is unpredictable
• Simulation in Rose-RT can be achieved only by step-by-step execution
Goal: Understand the notion of time in multidisciplinary modeling
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Outline
• Introduction: COMM within Bode-RC• Rose-RT• Simulink• Rose-RT and Matlab/Simulink: how to
couple?• State-of-affairs in COMM
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What is Simulink?
Simulink is a software package for modeling and simulating dynamic systems
process of computing a system’s states and outputs over a span of time, using
information provided by the system’s model
x(states)
u (input)
y (output)
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Components of a Simulink model
Continuous blocks respond continuously to changing input. Discrete blocks respond to changes in input only at
integer multiples of a fixed interval called the block’s
sample time.
y2 (output)x1
(states)u1 (input)
y1 (output) x2
(states)u2 (input)
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Structure of a Simulink model
• A typical Simulink model includes sources, systems and sinks.
Simulink provides:•graphical block diagram capability•drag-and-drop blocks facility
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Simulink Environment
The Library Browser displays a tree-structured view of the Simulink block libraries installed on your system.
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Motor model
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Components of a Simulink model
• Solvers
You can specify the solver to use in the model or when running a simulation.
A program, called ordinary differential equation (ODE) solver, updates block inputs and computes block outputs and states at intervals from the simulation start time to the simulation end time.
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Timing in Matlab/Simulink• The simulation time in Matlab/Simulink and real clock are not
the same
The amount of time it takes to run a simulation depends on
- model complexity, computer’s speed, solver’s type, etc.
• Simulation time and real time are not proportional
Simulation time can run faster time acceleration
slower time stretching
• Facilities for scheduling and dealing with concurrency are not offered
is not suitable for simulation of SW
Goal: Understand the notion of time in multidisciplinary modeling
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TrueTimeReal-time kernels and network transmissions can be
simulated• Different processing times, priorities, and arbitrary scheduling
policies in the computer nodes can be specified• Various network protocols may be evaluated• By introducing disturbing traffic on the network, the effects of
unpredictability in the network communication can be studied
Limitations• Code generated by other applications cannot be directly used in TrueTime framework
Goal: Understand the notion of time in multidisciplinary modeling
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Outline
• Introduction: COMM within Bode-RC• Rose-RT• Simulink• Rose-RT and Matlab/Simulink: how to
couple?• State-of-affairs in COMM
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Rose-RT and Matlab/Simulink: How to couple?
Goal: Explore ways of coupling of tools used in MD modeling
Approach 1 Approach 2
MCT
MATLAB/SIMULINK
ROSE-RTMATLAB/SIMULINK
ROSE-RT
Decision 3: select loosely-coupled architecture
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Rose-RT and Matlab/Simulink:Where to place timing?
Goal: Explore ways of coupling of tools used in MD modeling
• Not feasible due to the timing service of Rose-RT
Provide timing
MATLAB/SIMULINK
Timing request
Provide timing
Timing request
Data Data
ROSE-RT
MCT
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Rose-RT and Matlab/Simulink: Where to place timing?
Goal: Explore ways of coupling of tools used in MD modeling
Provide timing
MATLAB/SIMULINK
Timing request
ROSE-RT
Provide timing
Timing request
Data DataMCT
• Timing is enforced to both modeling toolsets• No advantage of Matlab/Simulink timing is taken
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Rose-RT and Matlab/Simulink: Where to place timing?
Goal: Explore ways of coupling of tools used in MD modeling
• Rose-RT timing is not used
• Matlab/Simulink provides a well-defined notion of simulation time
MCT
Provide timing
MATLAB/SIMULINK
Timing request
ROSE-RT
Provide timing
Timing request
Data Data
Decision 4: use Matlab/Simulink as a timing provider
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Outline
• Introduction: COMM within Bode-RC• Rose-RT• Simulink• Rose-RT and Matlab/Simulink: how to
couple?• State-of-affairs in COMM
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ToDo• Rose-RT automated step-by-step execution
changes in RTController needed (complex!)
• Rose-RT timing compatibility with Simulink replacement of Windows NT Timing Services
• Simulation in intended target environment
durations of execution of Rose-RT functions on a target OS should be available
State1 State2
InitialInitial
operation_durationoperation_duration
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Questions