Flexible tools for Interactive Model-Based
Control Design and Simulation
Roma 29-03-2007
Massimiliano Banfi
National Instruments - System Engineer
Graphical System Design
Design
Interactive Algorithm Design
• Control design
• Dynamic system simulation
• Digital filter design
• Advanced mathematics
Prototype
Tight I/O Integration
• I/O modules and drivers
• COTS FPGA hardware
• VHDL and C code integration
• Design validation tools
Deploy
Deployable Targets
• Rugged deployment platforms
• Distributed networking
• Human-machine interfaces
• Custom designs
Control Design Process
Modeling
and Design
System
Testing
Hardware-inthe-Loop
Testing
Rapid
Prototyping
Targeting
Modeling and Design
Setpoint
Error
Kc
Controller
Control
Output
Kp
Feedback
Plant
Modeling and design produce controller and plant
models
Rapid Control Prototyping (RCP)
Setpoint
Error
Kc
Controller
Control
Output
Kp
Plant
Creating a functional prototype of the controller
Feedback
Targeting Production Controller
Setpoint
Error
Kc
Controller
Control
Output
Kp
Feedback
Plant
Download control algorithm to production embedded target
Hardware-in-the-Loop (HIL) Simulation
Setpoint
Error
Kc
Controller
Control
Output
Kp
Feedback
Plant
Testing production controller with simulated plant
System Testing
Setpoint
Error
Kc
Controller
Control
Output
Kp
Plant
Feedback
Today’s Challenges
• Modeling and design
–
–
–
–
Iterative process
Models and design space are complex
Prototypes not readily available at start of process
Model tuning required based on empirical data
• Rapid control prototyping and HIL
– Hardware platforms are typically high cost and inflexible
– Significant development required to move from offline
simulation to real-time implementation
NI Platform for Control
LabVIEW Development Environment
Control Design Toolkit
System ID Toolkit
Simulation Module
State Diagram Toolkit
Simulation Interface
Toolkit
PID & Fuzzy Logic Toolkit
NI Motion Control
LabVIEW FPGA
Targets
LabVIEW Embedded
LabVIEW Real-Time
PXI
cRIO, cFP
RIO/DAQ Devices
32-Bit mp
PXI Platform for Real-Time
• I/O connectivity
–
–
–
–
–
–
–
–
Data acquisition
Signal conditioning
Dynamic signal acquisition
Motion control
Image acquisition
FPGA Reconfigurable I/O
Switching
Modular instruments
• Communication protocols
–
–
–
–
Ethernet
Serial
GPIB
CAN
• Chassis expansion through MXI
• 3rd party module support with NI-VISA
– Reflective memory, Mil Std 1553 Bus
Interface, IRIG B/Telemetry Board,
Syncro/Resolvers, Serial Sync Board
• 3rd party local displays with serial drivers
– NI Touch Panel Computer, QSI, Viewpoint
NI CompactRIO Reconfigurable
Embedded System
Reconfigurable Chassis
Real-Time Controller
I/O
I/O
I/O
I/O
I/O
Real-Time
Controller
I/O
I/O
I/O Modules
• DC power with redundant supply inputs
• 50 G shock
• -40 to 70 °C temperature
Connectivity
Signal
Conditioning
I/O
ADC

Field Programmable Gate Array
(FPGA)
• What it is
– A silicon chip with unconnected logic blocks
– User can define and redefine functionality
• How it works
– Define behavior in software
– Compile and download to the hardware
• When it is used
– Low volume applications that cannot afford ASIC fabrication
– Designs that require frequent changes or upgrades
Field Programmable Gate Array
(FPGA)
PROGRAMMABLE
INTERCONNECT
I/O BLOCK
Source: Xilinx
CONFIGURABLE LOGIC BLOCK (CLB)
Field Programmable Gate Array (FPGA) devices feature a reconfigurable digital circuit
architecture with a matrix of Configurable Logic Blocks (CLBs) surrounded by a
periphery of I/O Blocks. Signals can be routed within the FPGA matrix in any arbitrary
manner by Programmable Interconnect switches and wire routes.
CompactRIO MicroMo Motor Demo
Systems
• Direct connection to NI 9505
motor drive module
• Built-in Quadrature encoder
(512 CPR)
MicroMo 3242
Brushed DC Motor
NI 9505
Motor Drive Module
Step 1. Plant Modeling and Analysis
Speed
Setpoint
Error
Kc
Controller
Motor
Voltage
Kp
Plant
• Option A. Existing Model
• Option B. Mathematical Modeling
• Option C. System Identification
Actual
Speed
DC Motor Model
1
2
d (t )
Ri (t )  V (t )  K
dt
1
K
i (t )  V (t )   (t )
R
R
5
6
Note: Assume L (inductance) and b
(rotational friction) are very small
d 2 (t )
 T (t )  J dt 2
d (t )
J
 Ki(t )
dt
d (t ) K
K2
J
 V (t ) 
 (t )
dt
R
R
Laplace transform:
JRs  ( s)  KV ( s)  K 2 ( s)
3
4
DC Motor Model Cont.
Laplace transform:
JRs  ( s)  KV ( s)  K  ( s)
6
Reorganizing Terms
JRs  ( s)  K 2 ( s)  KV ( s)
7
Resultant Transfer
Function
2
Angular Speed
Input Voltage
 ( s)
K

2
V ( s ) JRs  K
8
Analyzing the Plant Model
• Time Response (Step Response)
• Frequency Response (Bode Plot)
• Pole-Zero Map
Property
Symbol
Units
Datasheet
Value
Measured Value
Resistance
R
Ohms
7.38
7.96
Inductance
L
H
4.64e-3
6.11e-3
Rotor Inertia
J
kg-m2
1.9e-6
16e-6
Friction Torque Constant
B
N-m-s
1.8e-6
Back-EMF Constant
Ke
V/rad/s
3.11e-2
3.12e-2
Torque Constant
Kt
N-m/A
3.11e-2
3.11e-2
Diode Threshold Voltage
Vth
V
0.7
0.8
 ( s)
K

2
V ( s) JRs  K
Demonstration: Mathematical Modeling
• Modeling in Simulink
• Modeling in NI Express Workbench
– Transfer Function (State Space, Zero-Pole-Gain)
• Modeling in LabVIEW
– Transfer Function (State Space, Zero-Pole-Gain)
– Time Domain Differential Equation
Demo
Step 1. Plant Modeling and Analysis
Speed
Setpoint
Error
Kc
Controller
Motor
Voltage
Kp
Plant
• Option A. Existing Model
• Option B. Mathematical Modeling
• Option C. System Identification
Actual
Speed
LabVIEW System Identification Toolkit
•
•
•
•
•
•
•
•
•
Identify and validate linear models of
systems from empirical data
Seamless integration with NI I/O
Parametric model estimation (both SISO
and MIMO)
Nonparametric model estimation
Recursive model estimation
Data preprocessing
Model conversion, validation, and
presentation
Closed-loop system identification with
feedback detection
Partially known “grey box” system
identification
Demonstration: System Identification
• System Identification Toolkit
– Stimulate and measure response
– Identify plant model coefficients
LabVIEW System ID Toolkit
LabVIEW System
ID Toolkit
Stimulus
Signals
AO0
Response
QE
System ID
Algorithms
DC Motor
Model
Mot Cmd
Tach
Demo
Step 2. Control Design
Speed
Setpoint
Error
Kc
Motor
Voltage
Controller
K
JRs  K 2
Plant
• Many Control Design Options
– Focus on Root Locus Method
– PID Synthesis
Actual
Speed
LabVIEW Control Design Toolkit
• Easily create interactive control
design and analysis VIs
• Model construction, conversion,
and reduction
• Time and frequency response
• Dynamic characteristics
• Classical control design
- root locus, PID, lead/lag ...
• State-space control and estimation
- LQR, LQG, pole placement,
Kalman filter ...
Demonstration: LabVIEW Control Design
LabVIEW Dev Sys
LabVIEW System
ID Toolkit
LabVIEW Control
Design Toolkit
LabVIEW Control Design Toolkit
DC Motor
Model
Controller
Model
Analyze
Design
Analyze
Closed-Loop
System
Plant
Controller
Demo
Step 3. Simulation
Speed
Setpoint
Error
 s  1 Ti 
Kc 

s


Controller
Motor
Voltage
K
2
JRs  K
Actual
Speed
Plant
• Simulate response to arbitrary inputs (vs. step
response, etc.)
• Simulate controller with non-linear and/or higher-order
plant models
LabVIEW Simulation Module
• Simulate dynamic systems including controllers and plants
• Real-time implementation for rapid control prototyping or hardware-in-the-loop
simulation
LabVIEW Simulation Module Features
• Linear systems – continuous and
discrete time
• Nonlinear system blocks and lookup
tables
• Fixed-step, variable step, and stiff
solvers
• Trimming and linearization
• Model hierarchy
• Integration with Formula node and
MathScript node (through subVI)
• Integration with 3D picture control for
system visualization
3D Picture Control w/ LabVIEW Simulation
•
•
•
•
•
Intern project, 2006
Charles Beaman, UT ME
undergrad
Transition into courses taught by
Prof. Beaman at UT
Current effort to put on
Connexions (Erik Luther)
Can be applied to courses in:
–
–
–
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Physics
Intro to Engineering
Dynamic Systems
Controls, …
Demontration: LabVIEW Simulation
Module Demo
LabVIEW Dev Sys
LabVIEW System
ID Toolkit
LabVIEW Control
Design Toolkit
LabVIEW
Simulation Module
LabVIEW Simulation Module
Speed
Setpoint
Controller
Model
DC Motor
Model
Actual
Speed
Demo
Step 4. Control Prototyping
Speed
Setpoint
Error
 s  1 Ti 
Kc 

s


RT PXI System/cRIO
Controller
Motor
Voltage
Electric
Motor
Plant
• Prototype controller with real-time hardware
– Download control algorithm to RT PXI
– Connect to actual plant system (electric motor)
Actual
Speed
Demontration: Real-Time Prototyping
• Simulation Module and LabVIEW Real-Time
– Implement controller on real-time hardware
LabVIEW Dev Sys
LabVIEW
Simulation Module
LabVIEW RT
Speed
Setpoint
LabVIEW Simulation Module
Controller
Model
Actual
Speed
DC Motor AO
Model Update
AI Scan
Demo
Step 5. Targeting Production Controller
Error
PRODUCTION Motor
 s  1 Ti 
Kc 
EMBEDDED

s


Voltage
CONTROLLER
• Production controller with real-world I/O
– Download control algorithm to production embedded
target
– Not connected to real-world plant
Demo
NI LabVIEW Embedded Development Module
• Deploy on any 32-bit processor
• Use the same LabVIEW graphical
programming to deploy to custom
devices
• More than 400 built-in numerical
analysis and signal processing
libraries
• Interactive front panel and block
diagram debugging
• C code generator for breadth of
toolchain and target support
LabVIEW Embedded
Development Module
Third party toolchain
Third party OS
Step 6. Hardware-in-the-Loop
Speed
Setpoint
Error
Production
Motor
Voltage
Controller
Controller
K
2
JRs  K
RT PXI
System
Plant Model
• Prototype plant with real-time hardware
– Download plant model to RT PXI
– Connect to production controller
Actual
Speed
7. Final Test and Verification
Speed
Setpoint
Error
NI Core!!!
Motor
Voltage
Actual
Speed
LabVIEW for Design, Prototype, and Deploy
LabVIEW conditional compiling
technology provides for:
– Model reuse
– Test reuse
RCP Target
Embedded Target
HIL Target
Benefits of LabVIEW Graphical System Design
Simulation
Configurable
Graphical Dataflow
State Diagram
Math Script
New LabVIEW MathScript
• Powerful textual programming for signal
processing, analysis, and math
– More than 650 built-in functions
– Reuse many of your m-file scripts created with
The MathWorks, Inc. MATLAB® software and
others
– Partially based on original math from
NI MATRIXx
• A native LabVIEW solution
– Interactive and programmatic interfaces
– Does not require third-party software
MATLAB® is a registered trademark of The MathWorks, Inc. All other
trademarks are the property of their respective owners.
Little or No Learning Curve for Customers Familiar
with The MathWorks Inc. MATLAB® Language Syntax
LabVIEW MathScript Syntax
MATLAB ® syntax
Little or No Learning Curve for The MathWorks,
Inc. Simulink® Software Users
• LabVIEW Simulation Module
• The Simulink Software Environment
Simulink® is a registered trademark of The MathWorks, Inc. All other
trademarks are the property of their respective owners.
LabVIEW is the original …
Little or No Learning Curve for The MathWorks, Inc. Simulink®
Software Users
LabVIEW
Simulation Module
The Simulink Software
Environment
Simulation Model Conversion
– Convert your plant and controller models developed in The MathWorks,
Inc. Simulink® environment into LabVIEW Simulation Module code
NI LabVIEW Simulation Interface Toolkit (SIT)
• Use the LabVIEW Simulation Interface Toolkit to:
– Build powerful user interfaces for models developed in the Simulink
environment
– Interact with, view, and control models from LabVIEW
– Deploy models to real-time hardware with LabVIEW Real-Time*
*Requires The MathWorks, Inc. Real-Time Workshop®
.
Real-Time Workshop® is a registered trademark of The MathWorks, Inc. All
other trademarks are the property of their respective owners.
LabVIEW Simulation Interface Toolkit (SIT)
LabVIEW Front Panel
Simulation Model
SIT Connection Manager
LabVIEW Controls and
Indicators
Model Parameters and
Signals
Control Design Development Paths
Design and
Analysis
MATRIXx
Xmath
Math Inter. TK
LV Script Node
LabVIEW
LabVIEW
System
Build
Prototyping and
HIL Testing
AutoCode
Simulation Interface
Toolkit (Future)
Simulation Interface TK (Future)
LabVIEW RT,
LabVIEW
Windows
Math Inter. TK
LV Script Node
The
MathWorks
Simulation
Code
Generation
MATLAB®
Simulation Interface
Toolkit
Simulink®
Simulation Interface Toolkit
RTW
References: MicroNova Simulator
Windows PC
(e.g. user interface)
PXI RT HIL
Simulator
Engine Control Unit (ECU)
MicroNova System
Display elements and connection panel for ECU
Signal conditioning
Realtime
computer
CAN-card
Analog Output
MicroNova Motor-HIL-card
based on NI FPGA card
Power supply
MicroNova CAN
(FPGA to cRIO Expansion Chassis)
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
– LabVIEW and NI hardware provide future
flexibility
– NI helped create an interface to a third-party
synchronous serial interface using NI-VISA
Siemens Power
HIL (Hardware-in-the-Loop) Simulation
Host and Server
Monitor
PXI RT System
I/O Signals
Steam Turbine
Simulator
Actual
Turbine Controller
White Goods
LabVIEW Real-Time, DAQ, and Simulink models
through the Simulation Interface Toolkit (SIT) are
used in the design and test of appliances.
NI Benefits
• Software
– One graphical programming approach for
Windows, Real-Time, FPGA, Prototypes, Embedded, Distributed & Control Design
• I/O
– Breadth: plug-in and distributed
– Price and Value
• Openness
– Software (e.g. DLL, SIT, ActiveX/COM, .NET, IVI, OPC, LabVIEW Tools Network)
– Hardware (e.g. CompactRIO Modules, PXI based on CompactPCI, PCIExpress)
– Virtual Instrumentation means to be able to do full systems in some cases and
integrate with others in other cases (e.g. when other products are already in use)
Visit the web site: www.ni.com\design
• Discuss products and configure your application
• Obtain estimated costs or a quote to take with you
• Request a free consultation – an NI engineer will
come to your office to:
– Discuss your application and specialized topics
– Demonstrate customized applications, examples,
and products
• Schedule an onsite seminar at your location