WS8-1 ADM730, Workshop 8, September 2005 Copyright 2005 MSC.Software Corporation WORKSHOP 8...

WS8-1ADM730, Workshop 8, September 2005Copyright 2005 MSC.Software Corporation

WORKSHOP 8

MSC.EASY5 & ADAMS/Insight


Problem statementTune the hydraulic valve positioning model to minimize the accumulated position error. Ensure that pressures in the actuator don’t exceed the rated specifications for the component.

WORKSHOP 8 – MSC.EASY5


Getting started

First, you will start MSC.EASY5 and import the model.

To start MSC.EASY5:1. Start an EASY5 command shell.2. Launch EASY5 using the command:

easy5x3. Load the model file named Hydraulic_Act.0.ezmf.

This is a simple hydraulic model that controls a positioning component in a larger model.

4. Specify features in use:Help -> License Features…Select the hc library feature for checkout.



Build the model, run an analysis:1. Build the model in EASY5:

Build -> Create Executable

2. Open the default analysis in the model: Analysis -> Open current analysis…

3. Check the simulation parameters under the General tab of the analysis. Ensure that:

Stop Time = 10 Time Increment = 0.01

4. Run the current analysis: Either press the ‘start’ button or do Analysis -> Execute from the

menus. When the simulation completes, the plotting window appears.



Inspect results, change parameters and re-run:

1. Plot the AccumulatedPositionError value. This is an indicator of system performance. What is the final value of this variable? (hold the middle mouse button down over a plot to query plot values):

___________________________________________

2. Alter the maximum pressure in the circuit: Double-click the VR (Pressure Relief Valve) component. Increase the ValveCrackPress to be 120.

3. Re-run the last simulation and inspect the accumulated error. Did the error increase or decrease with greater system pressure?

Increase / Decrease (circle one)



Identify parameters to study: The following list contains parameters that may influence the system

response. Examine the various blocks in the EASY5 model and try to determine the 2 (or 3)-letter abbreviation of the block its parameter name corresponding to each description below. The first has been done for you:

1. Extend piston area of the actuator component: AC2 -> piston_area_extend2. Displacement per revolution of the pump: _____________________3. Actuator piston mass: ___________________4. Relief valve cracking pressure: _________________5. Controller proportional gain constant: _______________



Identify outcomes of interest: Both the accumulated position error and the maximum pressure seen in

the actuator are of interest. Browse through the various blocks in the model and identify the block names and parameters that capture these two quantities:

1. Accumulated position error: IN -> AccumulatedPositionError2. Maximum extend pressure in the actuator: _____________________(Hint: It’s not in the actuator block, but is connected to the actuator block)3. Mean power in the pump: _____________________(Hint: Same as above: it’s not in the pump block)



Export model, load into ADAMS/Insight: Creating information about the EASY5 model for ADAMS/Insight is a

three-step process:1. Build an EMX representation of the model in EASY5:

Build -> Export Model As -> MAT EMX Function…Since no modifiers are being used, simply accept the default parameters here.

2. Document the EASY5 model:File -> Document Model -> Create HTMLThis creates model information needed by ADAMS/Insight.

3. Start ADAMS/Insight and import the EASY5 files:1. Launch ADAMS/Insight from a new EASY5 shell (File -> Open Command Shell):

adams05r2 ainsight

2. Create a new, blank experiment (File -> New)3. Attach the EASY5 simulation to this experiment:

Simulaton -> Add Simulation -> MSC EASY5Select the latest EASY5 model file.



Promote the Factors of interest: Within ADAMS/Insight, navigate the treeview list of Factors and promote

the following to be inclusion candidates: 1. Piston areas and mass of the actuator component:

1. AC2 -> piston_area_extend_AC2

2. AC2 -> piston_area_retract_AC2

3. AC2 -> PistonMass_AC2

2. Displacement/revolution of the pump: 1. PD -> DispPerRev_PD

3. Relief valve cracking pressure: 1. VR -> ValveCrackPress_VR

4. Controller gain constants:1. GB -> GKI_GB

2. GB -> GKP_GB Note that all Factors, by default, have a range of +/- 10% from the

nominal value. The defaults will be used for this experiment.



Promote the Responses of interest: Within ADAMS/Insight, navigate the treeview list of Responses and

promote the following to be inclusions: 1. Accumulated position error:

IN -> AccumulatedPositionError

2. Maximum pressure in Actuator: ST2 -> MaxActuatorPressure_ST2

3. Mean pump power: ST -> MeanPumpPower_ST

ADAMS/Insight uses the last value of the state to define the Response value. Entities such as the Statistics blocks (used above) let you capture other possibly desirable quantities. Custom post-processing can be done via user-defined Fortran blocks, as well.



Perform a screening study in ADAMS/Insight: To determine which Factors most influence the position error, run a

simple screening DOE study with the following specification: Strategy: DOE Screening Model: Interactions Design Type: Full Factorial

Before simulating the trials, look at the MSC.EASY5 entry under the Simulation node in the left-hand treeview. Ensure that the matCommand script has an end time (TMAX) of 10.0 seconds.

Simulate the trials then fit the results in Insight.



Investigating the results:

1. Create an HTML representation of the data by clicking the ‘Export to web..’ button.

2. Open the web page that is created in the local directory.3. In the upper window that displays Factor values, check the box entitled

‘Effects’ to see the Pareto diagrams for the Responses. 4. Considering the Pareto diagrams for the AccumulatedPositionError and

MaxActuatorPressure Responses. Which two Factors do not appear to affect either Response significantly:

1. ________________________________2. ________________________________



Fit a Response Surface, Optimize:

1. Save your work as ‘screening_study.xml’ for reference. 2. Delete the current Design Space by selecting it in the treeview and

hitting the delete button in the toolbar. 3. Reduce the list of Factors to three, including just the piston

extend/retract areas and the valve cracking pressure. 4. Create a DOE Response Surface experiment of quadratic order and

type Full Factorial. 5. Run the trials for this new experiment, then fit the results in Insight. 6. Use the Optimization functionality in Insight to determine the Factors

needed to: Minimize the position error Have the maximum actuator pressure be 100 psi Ignore the mean pump power Response


WS8-1 ADM730, Workshop 8, September 2005 Copyright 2005 MSC.Software Corporation WORKSHOP 8...

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