Implementing Hardware-in-the-Loop
(HIL) Test Systems
Christian Hahn
National Instruments
Closed-Loop Control
Disturbance
Desired
Speed
Motor
Controller
Motor
Command
Measured
Speed
DC Motor
2
Closed-Loop Control
Engine Control
Navigation
Control
Flight Control
Steam Turbine
Control
Dryer Cycle
Control
Print Head
Control
Medical Device
Control
3
Example…the automobile
3 ECUs  15 to 70 ECUs in 10 years
4
Embedded Control System Challenges
• Increasing application complexity
Test
Challenges
• Increasing reliability requirements
• Decreasing time-to-market
Test
Resources
• Reduce development cost
Are these mutually exclusive?
5
Testing Embedded Control Systems
System Level Testing
Test System
Test Profile
Logging/
Analysis
UUT
Disturbance
Desired
Speed
Motor
Controller
Measured
Speed
Motor
Command
DC Motor
6
Testing Embedded Control Systems
System Level Testing
• What if the “DC Motor” is not available yet?
• What if test failures could damage the ”DC Motor”?
• What if the ”DC Motor” is very expensive (capital,
maintenance, operation, facilities)?
• What if ”DC Motor” conditions
are not repeatable?
• What if there are numerous
variations of the ”DC Motor”?
Disturbance
Measured
Speed
Motor
Command
DC Motor
7
Testing Embedded Control Systems
Component Level Testing
Test System
Test Profile
Logging/
Analysis
UUT
Disturbance
Desired
Speed
Motor
Motor
Command
Controller
Measured
Speed
8
What is HIL Simulation?
• Types of Test






• Test Methods
Functional
Parametric
Validation (V&V)
Durability (HALT/HAST)
End-of-line
…


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Temperature/power
variation
Salt/sand spray
EM radiation
Mechanical
loading/resistance
HIL Simulation
…
9
Virtual Reality for your UUT
What does your UUT know about
the world around it?
UUT
Voltage
Desired
Speed
TCP
Motor
Controller
ENCODER
Motor
Command
Current
PWM
Impedance
Measured
Speed
Timing
10
Testing Embedded Control Systems
Virtual System Level Testing
Test System
Test Profile
Logging/
Analysis
MODEL
UUT
Desired
Speed
Motor
Motor
Command
Controller
Measured
Speed
Stimulus =
MODEL(test profile, UUT response)
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Testing Embedded Control Systems
Virtual System Level Testing
Test System
Test Profile
Logging/
Analysis
MODEL
UUT
Desired
Speed
Motor
Motor
Command
Controller
Measured
Speed
Stimulus =
MODEL(test profile, UUT response)
12
What is a Model?
m
k
c
13
Dynamic System Models
NI LabVIEW
MapleSoft MapleSim
The MathWorks, Inc. Simulink® Software
Esterel SCADE
Simulink® is a registered trademark of The MathWorks, Inc. All other trademarks are the
property of their respective owners.
14
ANSI C
NI MATRIXx SystemBuild
You Need a Model…
Test System
Test Profile
Logging/
Analysis
MODEL
UUT
Desired
Speed
Motor
Motor
Command
Controller
Measured
Speed
Stimulus =
MODEL(test profile, UUT response)
15
Control Design Process
Modeling
and Design
System
Testing
Rapid
Prototyping
Hardwarein-the-Loop
Testing
Targeting
16
Modeling and Design
Setpoint
Error
Kc
Controller
Control
Output
Kp
Feedback
Plant
Modeling and Design Produce Controller and Plant
Models
17
Modeling and Design Software Tools
• NI LabVIEW Simulation Module
• NI MATRIXx
• The MathWorks Inc., Simulink® Application
Software
• MSC CarSim
• Hand-coded models (C, Fortran, etc.)
Simulink® is a registered trademark of The MathWorks, Inc.
18
Rapid Control Prototyping
Setpoint
Error
Kc
Controller
Control
Output
Kp
Feedback
Plant
Creating a Functional Prototype of the Controller
19
Hardware-in-the-Loop Simulation
Setpoint
Error
Kc
Controller
Control
Output
Kp
Feedback
Plant
Testing Production Controller with Simulated Plant
20
HIL System Architecture
Host PC
Loads / Power
Real-Time
Fault Insertion
Simulator
Unit (FIU)
21
ECU
Loads, Power, and Faults
Simulated & Real Loads
Physical loads that would be seen by
the ECU
Break-out
Panel
Simulated and
Real Loads
Power
Supplies
Break-out & Power Supplies
Panel for manual fault insertion and
custom loads
Fault Insertion Unit
Programmatic fault insertion of open,
short to Vbatt, short to GND, ch-to-ch
Fault Insertion
Unit (FIU)
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HIL Functional Architecture
Host
User Interface
Model
Manager
Data Manager
Test
Sequence
Analysis &
Reporting
IO
RT Simulator
Simulator Interface
Datalogging
IO Interfaces
Sequencer/Profiler
Plant Model
Simulated Fault Insertion
RT IO Interfaces
Bus DMM/ FPGA IO AIO/DIO
RF / Cal / Diag
IO
Scope
Vision
SigCon
GPIB Interfaces
Fault Insertion Unit (Switching)
Power
Supply
Break-out
ECU
Loads
23
Manufacturing test of hydraulic actuators
Customer: Parker Hannifin
• Application

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
Integrate measurements with control
Control actuator movement deterministically
Easily change motion profile for each unit
• Solution
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LabVIEW Real-Time
Modular PXI hardware platform
NI DAQ I/O modules
• Saved 44 weeks of development time and reduced cost by 6x
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Lockheed Martin Simulator
(PXI, LabVIEW Real-Time, SIT, VISA)
• Application


Prototype integrated avionics unit in XSS-11
Create hardware-in-the-loop/HIL simulator
to test LIDAR (light detection and ranging
system) controller
• Key points
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LabVIEW and NI hardware provide future
flexibility
NI helped create an interface to a third-party
synchronous serial interface using NI-VISA
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