Development of a Flexible Platformfor Real-time Hybrid Simulation

Oya Mercan, Ph.D

Assistant Professor, University of Toronto

Quake Summit 2012July 9-12, 2012

Computational/Control Platform

NI PXI 1042 with a built-in NI PXI 8110 controller (deterministic, fast, CPU running RT with a built in clock)Field Programmable Gate Array, FPGA(high reliability, high determinism, true Parallelism, & re-configurability)SCB-68 (Break-Out-Box)(68 screw terminals for I/O signal conditioning)NI 5191 expansion chassis• NI 9237, Load Cell Module • NI 9239, LVDT Module • NI 9481, Relay Module

Computational/Control Platform

Experimental Setup

Software Development

• Safe start-up• Emergency/ regular shutdown•Command generation: either predefined or using an integration algorithm• Data logging and observation• State determination of the analytical substructure

•Interface with the I/O modules to receive and issue analog anddigital signals.• Limit checks• Data transfer• Control law• Dither injection

PXI- Real timeState Machine Based with 7 States

FPGA

FIFO

DMA

NI LabVIEWMATLAB Simulink

NI LabVIEW

NI LabVIEW

synchronization

LabVIEW VI for Tuning the PID Controller for a Single Actuator(Front Panel)

Software Development

Initialization State

Open up FPGA

Write the user defined values for calibration , constants PID gains, limits etc.on the FPGA

Enable/Disable buttons on the front panelWrite “False” to HSM Stop and Next buttons

Go to “Start up” state

Software Development

Start-up State

Wait for the user to turn HSM on

Disable PID gains and filename If Next button is hit go to “Pre Zero” stateIf Stop button is hit go to “Stop” state

Software Development

Pre Zero State

Software Development

Zero State

Impose user-defineddisplacements

Check if the limits, next or stop buttons have been hit, decide the next state

Software Development

Clear FIFO Memory

Open up the predefineddisplacementfile

Depending on whether the displacement file makes sense, decide the next state

Pre Run StateSoftware Development

Run State Impose predefined displacements within the timed loop

Write data to fileEither finish or abort the test and go to Startup

Software Development

Immediately turn the HSMhigh pressureoff

Stop State

Wait 5 seconds and turn off the low pressure and HSM completely

Software Development

FPGA VIThe relay channels in NI 9481 are being turned on/offdepending on the user input

Acquire restoring force data from NI 9237, perform limit check

measured displacementLimit check

command displacement

PID

Dither injection

Electrical command to the servo valve

Write data to the FIFO

Software Development

Verification Tests

To verify the developed software, hardware configuration, data transfer, as well as the PID tuning and tracking performance of the proposed system several predefined displacement histories were applied.

Real-time hybrid simulation considering one experimental

substructure

Pre Run State

Real-time Hybrid Simulation

Pre Run State – 1DOF Hybrid Simulation

Information about the dll file that contains the Integration algorithm and analytical substructure is extracted and made available to the other states

Depending on whether there is an error in the decide the next state

model dll file

Real-time Hybrid Simulation

Simulink model subsystem to be converted to model dll using Simulation interface toolkit

Real-time Hybrid Simulation

Analytical substructure

Real-time Hybrid Simulation

Analytical substructure

Integration Algorithm

Real-time Hybrid Simulation

Analytical substructure

Integration Algorithm

Real-time Hybrid Simulation

Pre Run State – 1DOF Hybrid Simulation

Information about the dll file that contains the Integration algorithm and analytical substructure is extracted and made available to the other states

Depending on whether there is an error in the decide the next state

model dll file

Real-time Hybrid Simulation

Error notification, let the user decide what to do next.

Real-time Hybrid Simulation

Run State – 1DOF Hybrid Simulation

Real-time Hybrid Simulation

• Software modification to control two actuators simultaneously with and without physical coupling.• Replacing PID control with other control laws.• Control of larger scale actuators (with three stage servo-valves) with the NI computational/control platform.

Current & Future Work

• NSERC Discovery (Grant 371627-2009)

• NSERC RTI (Grant 374707-2009 EQPEQ)

• Start-up funds from University of Alberta and University of Toronto

Acknowledgements

Thank you!

Questions ?

Real-time Hybrid Simulation

Experimental Setup

Mechanical ComponentsHydraulic power supply 3000 psi (pressurized oil)Hydraulic service manifold 120 gpm (continuous flow)2-Stage electro servo-valves 16.5 gpm (flow capacity)Hydraulic dynamic actuators ±7,5 kips (force) & ±5 inch (stroke)Built-in AC LVDT ±5 inch (stroke)Fatigue rated load cell ±12,500 kips (load capacity)