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Tutorials and Examples For tutorials of overall product use, see: Getting Started Using Adams/Car

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Page 1: Car Tutorials

Tutorials and ExamplesFor tutorials of overall product use, see:

• Getting Started Using Adams/Car

Page 2: Car Tutorials

Adams/CarExample Four-Post Analysis

466

Example Four-Post AnalysisAlthough this is an Adams/Car example, you can use the general concepts presented here to customize any template-based product.

• Setting Up and Running an Analysis: Teaches the expert user how to build and run a full-vehicle analysis with the four-post test rig.

• Creating and Running a Macro: Introduces the concepts of creating and running a macro for the scenario given above.

Page 3: Car Tutorials

467Tutorials and ExamplesExample Event Files

Example Event FilesIn Adams/Car, XML became the default file format for Driving Machine analyses. Although Adams/Car still supports driver control files (.dcf), it now automatically converts them to .xml. The .xml files are referred to as event files. Although the contents of the two files types look different, they contain the same event information. You work with .xml files through the Event Builder.

In the shared Adams/Car database, we provide files in both .dcf and .xml format. These files are stored in the driver_controls.tbl directory/table.

Page 4: Car Tutorials

Adams/CarExample .dcd File

468

Example .dcd FileThe following shows the architecture of a .dcd file and all the options you can set for a .dcd file. It contains options, logic, and general rules that you must follow when creating a .dcd file.

[MDI_HEADER]FILE_NAME = filename.dcdFILE_TYPE = 'dcd'FILE_VERSION = 1.0 FILE_FORMAT = 'ASCII'

(COMMENTS){comment_string}'Any comment'

[UNITS]LENGTH = 'meter' || 'millimeter' || 'centimeter' || 'kilometer' || etc.FORCE = 'newton' || 'kilogram_force' || etc. ANGLE = 'deg' MASS = 'kg'TIME = 'sec'

[CLOSED_LOOP]comment = string steering_control = 'none' || 'curvature' || 'path' || 'lat_acc' speed_control = 'none' || 'lon_vel' || 'lon_acc' || 'lat_acc' || 'path'ordinal = 'distance' || 'time'lon_vel_max = float lon_vel_min = float lon_acc_max = float lon_acc_min = float lat_acc_max = float lat_acc_min = float

(DATA) $ steering, speed $ 1 Case{none, none} -- null case, no data required!! $ 2 Case{none, lon_vel}$ 3 Case{none, lon_acc}$ 4 Case{none, lat_acc} -- NOT VALID$ 5 Case{none, path} -- NOT VALID { ( distance || time ) && ( lon_vel || lon_acc ) }

$ 6 Case{curvature, none} -- Must have distance with curvature{ distance && curvature }

$ 7 Case{curvature, lon_vel}$ 8 Case{curvature, lon_acc} $ 9 Case{curvature, lat_acc} $10 Case{curvature, path} -- NOT VALID{ ( distance || time ) && curvature && ( lon_vel || lon_acc || lat_acc ) }

$11 Case{path, none}$12 Case{path, lon_vel}$13 Case{path, lon_acc}$14 Case{path, lat_acc}{ x && y && ( lon_vel || lon_acc || lat_acc ) }

$15 Case{path, path}{ x && y && time }

$16 Case{lat_acc, none} -- NOT VALID

Page 5: Car Tutorials

469Tutorials and ExamplesExample .dcd File

$17 Case{lat_acc, lon_vel}$18 Case{lat_acc, lon_acc}$19 Case{lat_acc, lat_acc} -- NOT VALID $20 Case{lat_acc, path} -- NOT VALID { ( distance || time ) && lat_acc && ( lon_vel || lat_acc ) }

[OPEN_LOOP]ordinal = 'time' || 'distance' {distance || time steering throttle brake gear clutch}*

0.0 0.0 0.0 0.0 2 0.0 0.1 0.0 0.0 0.0 2 0.0

*You can select distance or time and any combination of steering, throttle, brake, gear, and clutch

.Example corresponding to $ 2 Case{none,lon_vel}:

.....[CLOSED_LOOP]STEERING_CONTROL = 'NONE'SPEED_CONTROL = 'LON_VEL'ORDINAL = 'TIME'(DATA){ TIME, LON_VEL }0.0 27.7770.1 27.7770.2 27.7760.3 27.7750.4 27.7740.5 27.773 .....

Example corresponding to $ 7 Case{curvature,lon_vel}:.....

[CLOSED_LOOP]STEERING_CONTROL = 'CURVATURE'SPEED_CONTROL = 'LON_VEL'ORDINAL = 'DISTANCE'(DATA){ DISTANCE, CURVATURE, LON_VEL }0.0 0.000 27.777 1.0 0.002 27.777 2.0 0.004 27.777 3.0 0.006 27.776 4.0 0.008 27.775 5.0 0.010 27.774 6.0 0.010 27.773 7.0 0.010 27.7748.0 0.010 27.7749.0 0.010 27.77410.0 0.010 27.77411.0 0.010 27.774 12.0 0.010 27.774 13.0 0.010 27.774 .....

Page 6: Car Tutorials

Adams/CarExample Suspension Loadcase File

470

Example Suspension Loadcase FileIn Adams/Car, you can use loadcase files to specify different types of suspension analyses. The following is an example loadcase file.

$-----------------------------------------------MDI_HEADER [MDI_HEADER]FILE_TYPE = 'lcf'FILE_VERSION = 4.0 FILE_FORMAT = 'ASCII'

$-----------------------------------------------UNITS[UNITS]LENGTH = 'mm'ANGLE = 'degrees'FORCE = 'newton'MASS = 'kg'TIME = 'second'$$Generation Parameters: (Do Not Modify!)$ loadcase = 1$ nsteps = 10$ bump_disp = 100.00 rebound_disp = -100.00$ steering_input = angle$ stat_steer_pos = 0.00$

$-----------------------------------------------mode[MODE]STEERING_MODE = 'angle'VERTICAL_MODE = 'length'

$-----------------------------------------------data[DATA]

$COLUMN: input type: type of input data: side:$ (c1) wheel z disp / force left$ (c2) wheel z disp / force right$ (c3) lateral force (y) left$ (c4) lateral force (y) right$ (c5 aligning torque (z-axis) left$ (c6) aligning torque (z-axis) right$ (c7) brake force (y) left $ (c8) brake force (y) right$ (c9) driving force (y) left$ (c10) driving force (y) right$ (c11) steering force / steer angle / rack travel { whl_z_l whl_z_r lat_l lat_r align_l align_r brake_l brake_r drive_l drive_r steer}-100.0000 -100.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000-80.0000 -80.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000-60.0000 -60.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 -40.0000 -40.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000-20.0000 -20.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.00020.0000 20.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.000040.0000 40.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 60.0000 60.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.000080.0000 80.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 100.0000 100.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000

Page 7: Car Tutorials

471Tutorials and ExamplesExample Wheel-Envelope Input File

Example Wheel-Envelope Input FileThe following is an example of a wheel-envelope input file (.wen) that you can use to control a wheel-envelope analysis.

$--------------------------------------------MDI_HEADER [MDI_HEADER]FILE_TYPE = 'wen'FILE_VERSION = 5.0 FILE_FORMAT = 'ascii'

$--------------------------------------------UNITS [UNITS]LENGTH = 'mm'FORCE = 'newton'ANGLE = 'deg'MASS = 'kg'TIME = 'sec'

$--------------------------------------------MODE[MODE]STEERING_MODE = 'angle'VERTICAL_MODE = 'length'

$--------------------------------------------GRID [GRID] BOUNDARY_STEERING_GRID = 100.0 BOUNDARY_WHEEL_GRID = 20.0INTERIOR_STEERING_GRID = 100.0 INTERIOR_WHEEL_GRID = 20.0

$--------------------------------------------DATA [DATA]$COLUMN: input type: type of input data: side:$ (c1) wheel z disp / force left$ (c2) wheel z disp / force right$ (c3) lateral force (y) left$ (c4 lateral force (y) right$ (c5) aligning torque (z-axis) left$ (c6) aligning torque (z-axis) right$ (c7) brake force (y) left$ (c8 brake force (y) right$ (c9) driving force (y) left$ (c10) driving force (y) right $ (c11) steering steer angle / rack travel$ {whl_z_l whl_z_r lat_l lat_r align_l align_r brake_l brake_rdrive_l drive_r steer}

-120.0 -120.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -500.080.0 80.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -500.090.0 90.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -300.0120.0 120.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -200.0120.0 120.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 200.0

Note: For wheel-envelope input files, Adams/Car ignores columns three through ten: (left and right) lateral force, aligining torque, brake force, and driving force.

Page 8: Car Tutorials

Adams/CarExample Wheel-Envelope Input File

472

85.0 85.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 350.080.0 80.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 500.060.0 60.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 500.0 30.0 30.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 450.0-30.0 -30.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 450.0-75.0 -75.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 500.0-120.0 -120.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 500.0

Page 9: Car Tutorials

473Tutorials and ExamplesExample Wheel-Envelope Output File

Example Wheel-Envelope Output FileA wheel-envelope output file (.wev) contains a header and a data table, as explained next.

The first three lines comprise the header and contain the following information, in this order:

• Type of file

• Adams dataset title

• Date and time of file creation

The table that follows the header contains the following information:

• The first column shows the solution step number

• Columns 2-4 show the data for the left wheel center x, y, z

• Columns 5-7 show the data for the left wheel axis point x, y, z

• Columns 8-10 show the data for the right wheel center x, y, z

• Columns 11-13 show the data for the right wheel axis point x, y, z

The following is an example of a wheel-envelope output file:

Adams/Car Wheel Envelope Analysis Output File - acar_v10.0Adams/Car Assembly2000-01-19 16:41:21

1 -4.2702 -673.57 205.00 -348.83 -1611.7 170.29 7.0293 670.69 205.00 303.63 1620.7 107.88

2 -4.6463 -681.45 225.00 -344.63 -1621.7 206.15 6.7629 678.55 225.00 307.97 1628.3 139.91

3 -4.9532 -687.82 245.00 -340.16 -1630.0 239.60 6.5706 684.92 245.00 311.28 1634.4 170.26

4 -5.2433 -692.82 265.00 -334.67 -1637.0 271.40 6.3755 689.93 265.00 314.35 1639.0 198.89

5 -5.5240 -696.55 285.00 -328.07 -1643.0 301.70 6.1779 693.66 285.00 317.43 1642.1 225.76

6 -5.7905 -699.08 305.00 -320.38 -1648.0 330.44 5.9864 696.18 305.00 320.67 1643.8 250.76

7 -6.0372 -700.45 325.00 -311.59 -1652.1 357.51 5.8099 697.55 325.00 324.25 1644.1 273.76

8 -6.2583 -700.71 345.00 -301.72 -1655.3 382.78 5.6583 697.79 345.00 328.31 1643.0 294.55

9 -6.4469 -699.89 365.00 -290.74 -1657.8 406.03 5.5424 696.93 365.00 333.04 1640.3 312.88

10 -6.5953 -698.01 385.00 -278.64 -1659.4 426.98 5.4752 695.00 385.00 338.63 1636.2 328.39

... .......

Page 10: Car Tutorials

Adams/CarExample Plot Configuration File

474

Example Plot Configuration FileThe following is an example of an Adams/Car plot configuration file:

$----------------------------------------------------------------------PAGE [PAGE] PAGE_LAYOUT = 11.0 NUMBER_OF_PLOTS = 1.0 PAGE_NAME = page_1 HEADER_LEFT_LINES = 1.0 HEADER_LEFT_LINE_0_TEXT = 'Header Left' HEADER_LEFT_TEXT_FONT_SIZE = 9.0 HEADER_LEFT_LINES = 1.0 HEADER_LEFT_COLOR = 788529153.0 FOOTER_RIGHT_LINES = 1.0 FOOTER_RIGHT_LINE_0_TEXT = 'Footer Right' HEADER_LEFT_LINES = 1.0 HEADER_LEFT_LINE_0_TEXT = 'Header Left' FOOTER_RIGHT_TEXT_FONT_SIZE = 9.0 FOOTER_RIGHT_COLOR = 788529153.0 $----------------------------------------------------------------------PLOT [PLOT] INDEX = 0.0 NAME = 'plot_1' TIME_LOWER_LIMIT = 0.0 TIME_UPPER_LIMIT = 0.0 AUTO_DATE_STAMP = 1.0 AUTO_ANALYSIS_NAME = 1.0 AUTO_SUBTITLE = 0.0 AUTO_TABLE_HEADER = 1.0 (LEGEND) {placement xloc yloc zloc fill } 2 55.46 85.03 0.00 1 (PLOT_BORDER) {color line_style line_weight} 788529153 1 1.0 (PRIMARY_GRID) {color line_style line_weight} 788529165 1 0.5 (SECONDARY_GRID) {color line_style line_weight} 788529165 1 0.5 (LEGEND_BORDER) {color line_style line_weight} 788529153 1 1.0 (NOTES) NUMBER_OF_NOTES = 3.0 (NOTE_1) {name font color autopos rotation alignment xloc yloc zloc isDate isAnalysis numStrings} 'analysis' 9 788529153 0 0.0 2 54.3200 4.7836 0.0000 0 1 0 1 STRING_1_TEXT = 'Analysis: test1_parallel_travel' (NOTE_2) {name font color autopos rotation alignment xloc yloc zloc isDate isAnalysis numStrings} 'date' 9 788529153 0 0.0 2 117.8513 4.7836 0.0000 1 0 0 1STRING_1_TEXT = '15:52:54 11-MAY-98' (NOTE_3)

Page 11: Car Tutorials

475Tutorials and ExamplesExample Plot Configuration File

{name font color autopos rotation alignment xloc yloc zloc isDate isAnalysis numStrings} 'NOTE_3' 10 788529163 1 0.0 4 82.6197 56.0575 0.0000 0 0 0 1STRING_1_TEXT = 'This is my note' (PLOT_AXES) {axis_name type label scaling divisions low_limit up_limit color font rotation alignment placement axis_offset axis_color label_autopos label_offset label_xloc label_yloc tic_color minor_divs auto_divs use_divs incs trailing_zeros dec_places sci_lower sci_upper num_font num_color} 'vaxis' 'vertical' 'No Units' 'linear' 8 0 0 788529153 9 90.0 3 0 0.0 788529153 0 10.9 43.4 49.3 788529153 2 1 1 1.0 0 4 -4 5 9.0 788529153'haxis' 'horizontal' 'Time (sec)' 'linear' 3 0 0 788529153 9 0.0 2 3 0.0 788529153 0 6.5 86.1 4.8 788529153 2 1 1 5.0 0 4 -4 5 9.0 788529153$----------------------------------------------------------------PLOT_CURVE [PLOT_CURVE] NAME = 'curve_1' PLOT = 'plot_1' VERTICAL_AXIS = 'vaxis' HORIZONTAL_AXIS = 'haxis' HORIZONTAL_EXPRESSION = 'toe_angle.TIME' VERTICAL_EXPRESSION = 'toe_angle.right' Y_UNITS = 'no_units' X_UNITS = 'time' LEGEND_TEXT = 'Right' COLOR = 'red' STYLE = 'solid' SYMBOL = 'none' LINE_WEIGHT = 2.0 HOTPOINT = 0.0 INCREMENT_SYMBOL = 1.0

Page 12: Car Tutorials

Adams/CarAdams/Car Dynamic Suspension Analysis

476

Adams/Car Dynamic Suspension AnalysisThis example demonstrates the ability to carry out Dynamic Suspension Analysis. Earlier, the Suspension Assembly was limited to carry out only quasi-static simulation. Now, your suspension assembly is simulated with Adams/Solver Simulate/Dynamic command.

This feature allows you to directly provide a RPCIII file or define View Functions to specify Jack and Steering motion as a function of displacement, force etc.

Model Description

Investigate the model and carry out a Dynamic Analysis

Here you first analyze a double wishbone suspension with rigid lower control arm

1. Start Adams/Car, Select Standard Interface.

2. Create a new Suspension assembly: File - New - Suspension Assembly. Fill the dialog box as indicated below. To select the subsystems, Right-click - Search - <acar_shared> to open the file browser.

A Suspension Assembly consisting of a double wishbone suspension and a rack and pinion steering system is provided.

A dynamic suspension analysis is carried out to actuate the wheel pads across a range of frequencies. We are interested in looking at the lower control arm bushing force and how the force changes by replacing the rigid lower control arm by a flexible body. In addition, we use the flex body swap dialog box to switch a rigid lower control arm with a flexible one. We then plot the stress on the flexible body node and visualize it.

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477Tutorials and ExamplesAdams/Car Dynamic Suspension Analysis

3. The suspension assembly should be displayed.

4. To simulate using the Dynamic Solver Statements, go to Simulate - Suspension Analysis - Dynamic.

5. You will use View Functions to define the vertical displacement of the Jack. The following function steps up the bounce-rebound amplitude from 10 mm to 30 mm with a frequency of 2 Hz: step(time,2,10*sin(4*pi*time),8,30*sin(4*pi*time))

(Tire Forces can be added using the function like Static Loads Analysis)

Page 14: Car Tutorials

Adams/CarAdams/Car Dynamic Suspension Analysis

478

6. To animate the results, from the Review menu, select Animation Controls. Animate the model and observe the change in the suspension travel.

Review the results

Plot the bushing force in the lca_front bushing:

1. Hit the F8 key in Adams/Car to switch to Adams/PostProcessor.

2. Locate the bkl_lca_front_force and bkr_lca_front_force REQUEST under user-defined REQUESTs:

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479Tutorials and ExamplesAdams/Car Dynamic Suspension Analysis

The fz_front component corresponds to magnitude of the force in the Z direction. Plot this quantity to obtain a figure similar to the following:

Change Rigid Lower Control arm to be a Flexible Body

Here you use the Flex body Swap dialog box feature available in the Standard interface to replace the left rigid lower control arm with a flexible body. The MNF file used for representing this flex body is created in Nastran.

To replace the lower control arm:

1. Go to Adjust - General Part - Rigid to Flex. This displays the flex body swap dialog box.

2. Right click the Current Part Field - Pick and select the Left Lower control arm. In the MNF File field, Right-click - Search - <acar_shared>\flexbodys.tbl and select the LCA_left_tet.mnf file.

Page 16: Car Tutorials

Adams/CarAdams/Car Dynamic Suspension Analysis

480

3. Click on the Connections tab next and highlight the Move column and click Preserve Expression button and click OK.

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481Tutorials and ExamplesAdams/Car Dynamic Suspension Analysis

4. Now, the rigid lower control arm in red is replaced by the white flexible body.

Simulate the Model

You again carry out a dynamic analysis with this model now containing a flexible body.

1. Go to Simulate - Suspension Analysis - Dynamic.

2. Name the Output Prefix to be Rigid_Flex and keep the remaining dialog box unchanged.

After the simulation is successful, animate the model to make sure it is behaving as expected.

Review & Compare Results

Here you plot the bushing force for the lower control arm and compare the force on left and right side.

To review the results:

1. Locate the bkl_lca_front_force and bkr_lca_front_force REQUEST under user-defined REQUESTs:

Page 18: Car Tutorials

Adams/CarAdams/Car Dynamic Suspension Analysis

482

2. Because of the left lower control arm being a flexible body, note the difference in the bushing force.

Optional: Load Durability Plugin to display Stresses and Identify the Hotspots

Here you will load the Durability Plugin and identify the hot-spots on the flexible lower control arm and also plot the nodal stresses. For better visualization, in the Adams/Car Standard Interface change the background color from Black to Gray (Settings - View Background Color).

To Display Stresses and animate the flex body:

1. Change to Adams/Postprocessor and switch to Animation mode.

2. Go to View - Load Animation - select Rigid_Flex_dynamic to load the animation.

3. Go to Tools - Plugin Manager and check the load Adams/Durability option.

Page 19: Car Tutorials

483Tutorials and ExamplesAdams/Car Dynamic Suspension Analysis

4. In the Animation tab right click the Component field and select the flexible body gel_lower_control_arm_flex. This only displays the flexible body and not the whole model.

5. Select the Contour Plots tab; set Contour Plot Type to Von Mises Stress and check Display Legend.

6. Select the Hot Spots tab; check Display HotSpots and fill the dialog box as shown below. You are interested in looking at the top 2 hotspots on the flexible body.

7. Play the animation; you would observe the change in stress with the hot spots being identified.

Page 20: Car Tutorials

Adams/CarAdams/Car Dynamic Suspension Analysis

484

8. From the above exercise, you can note that Node with ID 709 experiences the maximum Von Mises Stress. You can now, plot the stress at this node. Go to Durability menu at the top and select Nodal Plots. The dialog for Nodal Plots pops up. In the Select Node List field, fill in 709, Check Von Mises and click OK.

9. Switch back to Plotting mode in the Adams/PostProcessor, Set the Source to be Result Sets; select gel_lower_control_arm_flex_Stress and component to be node_709_Von_Mises. Your plot should look something like shown below.

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485Tutorials and ExamplesAdams/Car Dynamic Suspension Analysis

Remarks

• The above example, demonstrates a simple use of applying a non standard excitation to a suspension assembly. You could use an RPCIII file from test data to actuate your suspension or use other Adams/View functions. An example RPCIII file (roadprofile_lr_channels.drv) has been provided in the shared car database with your Adams installation (install_dir\acar\shared_car_database.cdb\loadcases.tbl).

• While animating or during plotting of the hot spots/stresses for the first time, you may see a progress bar. This is showing the caching of the Flex Cache Files for improving performance for future animation and post processing.

Page 22: Car Tutorials

Adams/CarAdding the vertical setup mode of Adams/Car Suspension Testrig

486

Adding the vertical setup mode of Adams/Car Suspension TestrigThis example demonstrates the enhancement of MDI_SUSPENSION_TESTRIG for quasi-static suspension analysis. The vertical mode named "VERTICAL_MODE_FOR_SETUP" in loadcase file is added to the suspension testrig. "VERTICAL_MODE_FOR_SETUP" means the vertical control method at time=0. Early the user could select only the "VERTICAL_MODE" for the simulation. This feature allows you to set the vertical mode method at the both condition the setup phase(time=0) and the simulation phase.

This new mode is very important for the model including adjustable force. Because when the user correlates with test data, it is important for users how the initial condition is setup in real world and in the simulation.

Model Description

Performing the analysis in order to investigate the vertical setup mode.

Here you first analyze a double wishbone suspension including adjustable force.

1. Start MD Adams 2010, Select Standard Interface.

2. Create a new Suspension assembly: File - New - Suspension Assembly. Fill the dialog box as indicated below. To select the subsystems, Right-click - Search - <acar_shared> to open the file browser.

A Suspension Assembly consisting of a double wishbone suspension including adjustable force and a rack and pinion steering system is provided.

We carry out quasi-static suspension analysis with two setup mode for vertical control. One is "wheel_center_height". Other is "contact_patch_height. And we then plot the toe angle in order to make sure the differences.

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487Tutorials and ExamplesAdding the vertical setup mode of Adams/Car Suspension Testrig

3. The suspension assembly should be displayed.

4. Go to Adjust - Adjustable Force. And select ".frontsusp_acforce.TR_Front_Suspension_torsional.afl_toe_adjustment" for the "Adjustable Force" field. Then you can see the desired value (-0.5). This value means that the toe angle is adjusted to -0.5 at setup phase.

5. Go to Simulate - Suspension Analysis - Parallel Wheel Travel…

6. Set up the analysis as follows. In this case, the vertical travel of the wheel is controlled to keep 0mm in setup phase.

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Adams/CarAdding the vertical setup mode of Adams/Car Suspension Testrig

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7. Select OK.

8. Go to Simulate - Suspension Analysis - Parallel Wheel Travel… again

9. Set up the analysis as follows for the second analysis. In this case, the vertical travel of the contact patch is controlled to keep 0mm in setup phase.

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489Tutorials and ExamplesAdding the vertical setup mode of Adams/Car Suspension Testrig

10. Select OK.

Review the results

Plot the toe angle in two analyses:

1. Hit the F8 key in Adams/Car to switch to Adams/PostProcessor.

2. From the simulation list, select the two analyses.

3. From the right of the dashboard, set Independent Axis to Data. (The Independent Axis Browser appears. You perform the next four steps in the browser.)

4. From the Request list, select wheel travel. You might have to scroll down to see this entry.

5. From the Component list, select vertical_left.

6. Select OK.

Note: "Absolute" at "Control Mode" means that the vertical displacement is controlled the displacement with absolute value. "Relative" means that the displacement is relative to the position at the setup phase.

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Adams/CarAdding the vertical setup mode of Adams/Car Suspension Testrig

490

7. Locate the testrig.toe_angle REQUEST under user-defined REQUESTs. And select left in component list.

8. Select Add curve. You can see the plot of wheel_travel vs toe_angle.

The toe angle in Red line(case1...) should be -0.5 by adjustable force when wheel_travel is 0.

9. Create New page.

10. From the right of the dashboard, set Independent Axis to Data. And select jfl_jack_force_data in request list and displacement in component list.

11. Plot the toe angle again. You can see the plot of contact_patch_height vs toe_angle.

The toe angle in Blue line(case2...) should be -0.5 by adjustable force when contact_patch_height is 0.

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491Tutorials and ExamplesAdding the vertical setup mode of Adams/Car Suspension Testrig

Remarks

• "VERTICAL_SETUP_MODE" is available with all quasi-static suspension analysis. When you create the loadcase file, the setup mode is described as follows in loadcase file.

[MODE] STEERING_MODE = 'angle' $ wheel_center_height/ contact_patch_height VERTICAL_MODE_FOR_SETUP = 'contact_patch_height' VERTICAL_MODE = 'wheel_center_height' VERTICAL_TYPE = 'absolute' COORDINATE_SYSTEM = 'vehicle'

• "Control Mode" is also described as follows in loadcase file.

[MODE] STEERING_MODE = 'angle' $ wheel_center_height/ contact_patch_height VERTICAL_MODE_FOR_SETUP = 'contact_patch_height' VERTICAL_MODE = 'wheel_center_height' VERTICAL_TYPE = 'absolute' COORDINATE_SYSTEM = 'vehicle'

Page 28: Car Tutorials

Adams/CarAdding the length mode for roll analysis of Adams/Car Suspension Testrig

492

Adding the length mode for roll analysis of Adams/Car Suspension TestrigThis example demonstrates the enhancement of MDI_SUSPENSION_TESTRIG for quasi-static suspension analysis. The length mode is added to roll analysis of the suspension testrig. The length mode means that the user can define the vertical length of the center of the table for roll analysis. Early the user could set only vertical total force. This feature allows you to set the vertical mode the either of Force or Length for roll analysis.

Model Description

Performing the roll analysis in order to investigate the vertical mode.

Here you first analyze a double wishbone suspension including adjustable force.

1. Start MD Adams 2010, Select Standard Interface.

2. Create a new Suspension assembly: File - New - Suspension Assembly. Fill the dialog box as indicated below. To select the subsystems, Right-click - Search - <acar_shared> to open the file browser.

A Suspension Assembly consisting of a double wishbone suspension including adjustable force and a rack and pinion steering system is provided.

We carry out roll analysis in quasi-static suspension analysis with two setup mode for vertical control. One is "Force". Other is "Length". And we then plot some requests in order to make sure the differences.

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3. The suspension assembly should be displayed.

4. Go to Adjust - Adjustable Force. And select ".frontsusp_acforce.TR_Front_Suspension_torsional.afl_toe_adjustment" for the "Adjustable Force" field. Then you can see the desired value (-0.5). This value means that the toe angle is adjusted to -0.5 at setup phase.

5. Go to Simulate - Suspension Analysis - Roll & Vertical Force…

6. Set up the analysis as follows. In this case, the vertical mode is controlled with Force mode during the simulation.

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7. Select OK.

8. Go to Simulate - Suspension Analysis - Roll & Vertical Force… again

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9. Set up the analysis as follows. In this case, the vertical mode is controlled with Length mode during the simulation.

10. Select OK.

Review the results

1. Hit the F8 key in Adams/Car to switch to Adams/PostProcessor.

2. From the simulation list, select the first analyses named "mode_Force_roll_angle".

3. From the right of the dashboard, set Independent Axis to Time.

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4. Locate the left_tire_force and right_force REQUEST under user-defined REQUESTs. And select normal in component list.

5. Select Add curve. The sum of two curves is always 6000N.

6. Create New page.

7. From the simulation list, select the first analyses named "mode_Length_roll_angle".

8. Locate the jfl_jack_force_data and jfr_jack_force_data REQUEST under user-defined REQUESTs. And select displacement in component list.

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9. Select Add curve. The sum of two curves is constant. This means that the center of the table is constant during simulation.

Remarks

• When you create the loadcase file for roll analysis, the vertical setup mode is described as follows in loadcase file.

[MODE] STEERING_MODE = 'angle' VERTICAL_MODE_FOR_SETUP = 'wheel_center_height' $ roll_angle / roll_angle_disp VERTICAL_MODE = 'roll_angle_disp' COORDINATE_SYSTEM = 'iso'

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General Actuation Analysis feature examples

Extended description:

• Perform actuation analysis on assemblies.

• Create and modify RPC request map files in a much easier fashion.

• Create and modify actuator setting files (actuator input files) to "import/export" actuator settings.

• Modify actuator parameters in an assembly.

Submitting an actuation analysis

For submitting an actuation analysis, do the following,

1. Open a valid assembly for analysis. The example assembly (actuation_example.asy) provided with the installation may be used as an example.

2. Open the 'General Actuation Analysis' dialog from the menu. (Simulate -> General Actuation Analysis -> Submit Analysis). Note that all valid assemblies open in a session can be accessed through the drop down provided.

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3. Enter the required parameters in the dialog. Note that the input parameters can be categorized into 3 classes (output control, simulation, actuator setup) as shown in the figure above.

Output control parameters: To define the output files generated as part of the analysis.

Simulation parameters: To define the simulation length, mode etc.

Actuator setup: To setup the actuator parameters.

Note that the actuator setup is done through the 'RPC request map file' and the 'Actuation input file'. Sample files have been provided with the installation and may be used as an example.

4. Hit the OK or Apply button of the dialog, when all parameters have been input. Note that the environment variable MSC_FLATTEN_ADM should not be set.

5. The simulation progress will be indicated by verbose messages displayed in the message window.

6. The end of the simulation will be indicated as shown in the snapshot below,

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7. Once the analysis is finished, open the post processor (F8) and import the RPC file (extension .rsp) generated as part of the simulation output. The RPC would be located in the current working directory of the session. Plot the results. An example plot is shown in the figure below,

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Setting actuator parameters

The user is provided with the option of using a wizard of a tabular interface for editing actuator data. These options can be accessed through the Adjust - Actuators - Table/Wizard menus.

The wizard interface is as shown in the figure below,

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The desired assembly can be selected from the drop down list of valid assemblies open in the session. Upon selection, all actuators in that assembly are populated in the Actuator drop down.

The desired actuator can be selected either through the drop down or using the up-down arrow buttons. Parameter data related to the selected actuator is displayed in the dialog below and can be set by the user. The settings are saved to the assembly, using the OK/button. Facility is provided to switch to the "table view" from the wizard.

The "table view" for setting actuator parameters is shown below,

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The table like interface provides the user with an easy way of looking at a list of actuators at once and activating/deactivating an entire selection. As shown in the figure the desired set of actuators is selected first. Using the 'Activate Selection' and 'De-activate Selection' buttons, the selected set can be activated and de-activated at once.

Besides this, the user can choose to edit the list of selected actuators in the wizard view, using the 'Edit Selection in Wizard' button.

The actuator settings can be saved to a file using the Request map editor functionality, described later.

Request map editor

The request map editor allows the user to work with (view or edit) requests that are defined in the database or import a request map file and edit the requests defined there. The request map editor functionality can be accessed from the menu-group Simulate - General Actuation Analysis - Request Map Editor.

In the "database mode", the user can select to display all browse for a set of requests from the assembly to select (Using the All and Browse buttons respectively).

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In order to edit the request data in the table, the user needs to explicitly switch to the edit mode, using the corresponding check button provided.

The request data is displayed to the user in the tabular form and can be sorted, which makes it easier to locate and edit the desired request(s). The user may choose to apply the changes to the assembly directly, or alternatively, save the data to a request map file.

Opening/Saving an actuation input map file

An actuation input map file contains a series of parameter-value pairs corresponding to one or more actuators in an assembly. The parameters include major and minor roles of the actuator, scale factor, offset, time offset, RPC function etc. Such a file provides an easy way of setting up a large number of actuators at once.

A facility has been provided to the user to view/open an actuation input map file or create one using actuator data from a valid assembly. The open/save functionality can be accessed from the menu-group Simulate - General Actuation Analysis - Actuation Input File.

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It's not necessary to have any valid active assemblies open in a session, in order to view an existing actuation input file. Select the desired file and click on the button with a magnifying glass, in order to open the file. Note that the file gets opened in the user set editor as defined by the optional environment variable MDI_ACAR_USE_EDITOR. If the variable is not defined, then the file is opened in the message window.

If a valid assembly is open in the session, then the verify functionality is available, by which the user can compare the actuator data in an assembly, with that in the file. The comparison reports actuators present in the file that are absent in the assembly as well as incorrect roles set for the actuator, if any. A sample comparison message is shown below,

Alternatively, a valid assembly can be opened and the actuator settings can be changed manually for each desired actuator. Using these settings, an actuation input map file can be generated as follows,

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A facility to export the settings of actuators that belong to the specific type is provided. By default data belonging to all actuators within an assembly is exported. Specify the file name and the database location to save the file and hit the OK/Apply button to create the file.

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Path optimization feature example

Extended description:

Path optimization is a tool that builds a path around a closed road course that approximates the optimum or fastest path for a given vehicle. With this tool, we can visualize the input road file overlaid with the centre line for the optimized path.

In ACar, use Simulate->Full Vehicle Analysis->Path Optimization command to launch the tool. The dialog for path optimization in ACar looks like the one as below

The input road file can be visualized when the "Show" button is pressed. The mandatory fields on this dialog are the "Input Road Data File" and the "Output Path File Name". The road specified by input file can be optimized by providing values for mandatory fields and hitting the OK/Apply button. The output file generated contains the optimized road.

After the optimized road file is generated, the centerline for the optimized path is shown overlaid with the input road. The figure below shows input road file overlaid with the red line, which is the centre line for the optimized path.

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In AChassis, use Utilities->Path Optimization command to launch the tool. The dialog for path optimization in AChassis looks like the one as below

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