Real-Time Controllers Phillips

8/10/2019 Real-Time Controllers Phillips

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Real-Time Controllers

Brian Phillips


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Overview and capabilities

Use in industry

System details

Products xPC Target

dSpace

CompactRIO Use in research

Concluding remarks


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Use in industry

System details

Products xPC Target

dSpace


Concluding remarks


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Overview

Basic idea: combines control and dataacquisition with dedicated, fast hardware

Advantages: speed, reliability, and versatility Disadvantages: cost, mess of buzzwords,

steep learning curve

Current status: used extensively throughoutautomotiveand aerospaceindustry andsomewhat in communication, power, andautomation


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Capabilities

Efficient computing facilitates real-time control

Dedicated devices can be more compact andportable than desktop computers

Many flexible alternatives available with expandableand interchangeable I/O cards and panels

Allow for rapid prototyping of system usingcombination of numerical and analytical components

Simulation of complex environment for exhaustivetesting of existing component

Definition: The process of quickly assembling a working model to evaluateportions of the design. Aimed at reducing risk and cost.Definition: Ratio of simulation time to actual time is 1:1


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Prototyping

Simulation

System of Interest

System of Interest


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Use in industry

System details

Products xPC Target

dSpace


Concluding remarks


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Uses in Automotive

Prototype electronic control unit (ECU) fordesign and testing Engine control unit

Climate control unit Speed control unit

Anti-lock brakes, etc

Simulate road conditions for exhaustingvirtual testing of ECUs (virtual plant)

Complications of alternative fuel cars

Prototype:

ECU

Plant:

Car


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Uses in Aerospace Simulate flight loads on components Evaluate pressure and climate control strategies

Prototype vibration control strategies


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Use in industry

System details

Products xPC Target

dSpace


Concluding remarks


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Typical Components for

Hardware-in-the-Loop Simulation

Host computer Real-time target computer

I/O Cards

CodeGeneration

Apply Excitation

Measure Feedback

Experiment

Host PC

SimulinkLabview

Monitor Results

Definition: Simulation technique where anembedded system (actual electronic or physical

component of interest) is tested in real-time with aplant simulation (numerical model of the remainingsystem components)

Target PC


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Inner Workings of a Real-Time

Controller

CompactRIO Data Flow Diagram, courtesy of NI


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Real-time controller types

Single card

Fits inside host computer

Require I/O panel

Dedicated Unit

Modular

Full scale

Industrial level application

Very large


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xPC Target

Produced by the MathWorks, the samecompany as Matlab

Focused around engineer friendly Matlab

Designed to work with Simulink and RealTime Workshop

Laptop host with compact target


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xPC Target Advantages

Target system may be any computer, utilizing over250 standard I/O boards, including NI

Inexpensive, on the order of $5,000, depending ontypes of I/O cards

xPC Target Disadvantages The Mathworks does not manufacture hardware

User must create target PC to suit their own needs,requiring familiarity with signal conditioning A/Dconversion, computer hardware, etc.

Arguably the least proven real-time control system

of the three


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dSpace

Produced by dSpace, headquartered inGermany

Designed to work with Simulink and RealTime Workshop

Large footprint in the automotive andaerospace industry

Mid-SizeDedicated Unit


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dSpace Advantages

Experienced company, founded in 1988 (Germany)and 1991 (North America)

Very proven system, especially in the automotivesector (13,000 systems worldwide)

Clients range from Boeing to Volkswagen Numerous success stories

Extensive array of software, simulation packages,visualization tools, hardware options

dSpace Disadvantages

Expensive, on the order of $30,000 for basic system


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CompactRIO

Produced by National Instruments

Designed to work with LabVIEW Real-Timeapplications

Focus on standalone hardware device

CompactRIO


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CompactRIO Advantages

NI heavily pushing CompactRIO

Rugged construction (50 g shock protection!)

LabVIEW derivatives at core of modeling

Moderately priced at $15,000 for basic system

CompactRIO Disadvantages

Can use Simulink and Real-Time Workshop,but in a roundabout way

Requires both knowledge of Simulink and

LabVIEW


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Use in industry

System details

Products xPC Target

dSpace


Concluding remarks


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Research Applications

Hybrid Testing

Embedded system: experimental substructure

Plant simulation: numerical substructure

Prototyping of structural control algorithms

Active energy dissipation devices

Active mass dampers, actuators

Semi-active energy dissipation devices

Variable orifice dampers, MR dampers


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Application in Hybrid Testing

k2

G

Force Factor

Numerical Stiffness

k1

Key

AccelerationForce

Displacement

k1

m

c

Discrete State-Space

Servo Control Loop

k2

ExperimentalStiffness

Real-Time Controller

Structure of Interest

gx

GroundMotion


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Laboratory

Application

Actuator

LVDT

Specimen

dSpace Computer

I/O Panel

Servovalve

Load Cell

Servo Controller

Servo Control Loop

Real-Time Controller

Experiment


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Use in industry

System details

Products xPC Target

dSpace


Concluding remarks


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Conclusions

Technology readily available for real-time control

Requires some detailed investigation

Choice of system depends on

Budget, number of channels, sample rate, comfort

Advances will lead to wider use

Increase sampling rate

Increase number of I/O channels

Potentially increase number of competitors

Decrease cost


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Main References

dSPACE

http://www.dspaceinc.com/

The Mathworks

http://www.mathworks.com/products/xpctarget/

National Instruments

http://www.ni.com/compactrio/


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Thank you

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Real-Time Controllers Phillips