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HIL Presentation, v1.0 © Hans N Page 1Sandra Claesson, Prevas
HIL Presentation, v1.0 © Hans N Page 2
Agenda
� Embedded systems� Challenges in testing ES� Test types and methods
� HIL� Definition� HIL system� Architecture� Model� FISC� Options� Example
� When to use HIL� Tips and tricks
HIL Presentation, v1.0 © Hans N Page 3
Embedded systems
Printers
Engine Control
Washing machine
Navigation System
Medical Devices
HIL Presentation, v1.0 © Hans N Page 4
Challenges, testing embedded devices
� Increasing application complexity
� Increasing reliability requirements
� Decreasing time-to-market
� Reduce development cost
Test
Challenges
Test
Resources
HIL Presentation, v1.0 © Hans N Page 5
Test types and methods
� Types of Test� Functional
� Parametric
� Validation (V&V)
� Durability (HALT/HAST)� …
� Test Methods� Temperature/power
variation
� EM radiation
� Mechanical loading/resistance
� HIL Simulation
� …
HIL Presentation, v1.0 © Hans N Page 6
What is HIL Simulation ?
The use of real-time I/O hardware to simulate the dynamic behavior of a device that interfaces to the Unit Under Test.
Dynamic – stimulus reacts to the response of the UUT (closed-loop)
Static – stimulus ignores the response of the UUT (open-loop)
The simulator may use programming languages, state charts, modeling languages or other methods to describe the input/outputbehavior (dynamics) of the device
HIL Presentation, v1.0 © Hans N Page 7
HIL system
UUTModelTest Case
Real application
SimulatedLoads
SimulatedSensors
HIL Presentation, v1.0 © Hans N Page 8
System Architecture
UUT
Loads
Fault Injection& Signal
Conditioning(FISC)
Real-TimeSimulator
Host computerPower
HIL Presentation, v1.0 © Hans N Page 9
Real-time execution
Real-time Physical I/O
Host computer
Model
I/O Handling Scheduling
FISC
HIL Presentation, v1.0 © Hans N Page 10
What is a Model ?
c
m
k
Algorithmic representation of the
behaviour of a physical system
HIL Presentation, v1.0 © Hans N Page 11
Host computer
Realtime target
Physical I/O
Host computer
GUI Test sequence Configuration
FISC
HIL Presentation, v1.0 © Hans N Page 12
Fault Insertion & Signal conditioning
Simulatedloads and sensors
Power Supply
I/O UUT
Interference signals(GND, Vcc or others )
Fault InjectionSignal conditioning
Interference signals(GND, Vcc or others )
HIL Presentation, v1.0 © Hans N Page 13
Example, Volvo Aero
The Engine Control for the JAS-39 GripenFighter Aircraft, is continuously maintained and updated and require thorough testing before release into a real aircraft.
One major part of the testing is HIL simulation making it possible to execute system tests without the need of real engine testing.
HIL Solution: � Hardware build upon commercial hardware (COTS)
PXI with I/O boards and a large external GPIB controlled AC Power Source. � Complex I/O signals simulated using programmable FPGA PXI boards. � System operated by a normal desktop PC running windows XP� All software is developed using LabVIEW.
HIL Presentation, v1.0 © Hans N Page 14
When to use HIL ?
� Closed loop control systems (Requires dynamic testing)
� Complete system test is difficult to handle� Difficult to get access to complete system
� Many different products/variants
� Expensive to operate complete system
� Need for testing of abnormal behaviors� Over speed, Overload
� Signal errors, interference UUTModelTC
Load
Sens
HIL Presentation, v1.0 © Hans N Page 15
Tips and tricks
� Build your system flexible� All products will continually change and you need to be able to
adopt to those changes
� Use commercial tools and equipment (COTS) as much as possible.
� Specify and build or buy a system that fits your organization.
� Ensure that you have the knowledge needed to specify, (build), operate and maintain the HIL system.
