Tracked Vehicle Modeling
In this tutorial, you will learn how to use MotionView to build a tracked vehicle and simulate a track vehicle on a soft soil road passing over a few obstacles.
Before you begin, copy the file(s) used in this tutorial to your
working directory.
Model Overview
- Open a new MotionView session.
-
From the File menu, click on Extension
Manager and load the Vehicle Tools
extension.
- Open the Track_Start.mdl model file.
-
Review the model.
- The model is in the mm, Kg, N, sec unit system.
- The model has two systems: Body and Suspension.
- The Body system contains the Vehicle body (Frame) and Engine fixed to each other.
- The Suspension system has three trailing arms connected with a torsional spring damper.
- There are two unresolved motions used to drive the vehicle, Motion Left and Motion Right.
Create Rolling Systems
-
From the Vehicle Tools menu, under Track
Builder select Rolling systems.
The Create rolling system dialog is shown below:
- Under Parent System, select Suspension.
-
Select the Symmetric pair check box to create both the
left and right rolling system together.
Note: The symmetry needs to be about the x-z plane. The Symmetric pair does not create MotionView pair entities, instead it creates two entity copies positioned in the symmetry plane.
- Click on Attach to single/left and select the Frame body.
- Click on Attach to right and select the Frame body.
- Specify sysr_sprocket and Sprocket as the Rolling system varname and Rolling system label.
- Select the Rolling system type as Sprocket.
-
Enter the following parameters:
Center X Center Y Center Z Radius Thickness Number of Teeth 0 -500 400 200 100 16 -
Click Apply to create the sprocket systems and continue
in the Creating rolling system dialog.
The complete dialog is displayed below:
-
Repeat steps 2 to 9 using the following table to create three symmetric rolling
systems of type Wheel.
Tip: Use the Apply button to keep the dialog open when creating multiple rolling systems.
Parent System Attach to Single/Left Attach to Right Rolling system varname Rolling system label Center Radius Thickness X Y Z Suspension Front Arm-Left Front Arm-Right sysr_frontwheel Front Wheel 300 -500 0 200 100 Suspension Mid Arm-Left Mid Arm-Right sysr_midwheel Middle Wheel 800 -500 0 200 100 Suspension Rear Arm-Left Rear Arm-Right sysr_rearwheel Rear Wheel 1300 -500 0 200 100 The model with the rolling systems is shown below: -
Update the joint of Motion Left to Sprocket
LH Joint Rev by selecting the revolute joint in the
Sprocket LH system.
- Update the joint of Motion Right to Sprocket RH Joint Rev by selecting the revolute joint in Sprocket RH system.
- Save the model as Track_RollingSystems.
Create Track Systems
-
From the Vehicle Tools menu, under Track
Builder select Create Tracks.
The Create track dialog is displayed:
- Select Suspension as the Parent System.
- Set the Wrap varname as sysw_trackleft and the Wrap label as Track Left.
-
Enter 4 in the Total number of
Entities field to wrap on the four rolling systems that were
created.
This will update the entity selector table to enter four values.
-
Select Systems to wrap in the order shown below. Keep
Wraptype as Inside for each
system.
- Sprocket LH
- Rear Wheel LH
- Middle Wheel LH
- Front Wheel LH
- Select Single Pin as Chain/Belt Properties.
- Enter Link length as 85.0, Link thickness as 40.0, and Link width as 150.0.
- Enter 50 for Number of links/segments as suggested in the Minimum number of links.
- Select 1-Rotation and bending stiffness for Link DOF.
- Under Soil Interaction, select Soft Soil.
- Under Soil terrain file, select heavy_clay_25_custom_obs.rdf from Altair HyperWorks installation directory <install_dir>\hwdesktop\hw\mdl\autoentities\properties\Tires\ALTAIR_SOFTSOIL\SoilLibrary.
-
Select the Road Reference Marker as Soil
Reference Marker.
The complete dialog is displayed below:
-
Click OK to create the left side track.
- Open the Create Tracks dialog to build the right side track. The previous selections are stored in the dialog.
- Select Suspension as the Parent System.
- Set the Wrap varname as sysw_trackright and the Wrap label as Track Right.
-
Select Systems to wrap in the order shown below. Keep
Wraptype as Inside for each
system.
- Sprocket RH
- Rear Wheel RH
- Middle Wheel RH
- Front Wheel RH
- All other fields are already populated with the parameters from the left side track. Click OK to create the track and close the window.
-
The completed model is shown below.
-
Click on Road Tools to invoke the dialog.
- Under File, load the heavy_clay_25_custom_obs.rdf file from the installation directory <install_dir>\hwdesktop\hw\mdl\autoentities\properties\Tires\ALTAIR_SOFTSOIL\SoilLibrary.
-
Under MDL, select a location to save the
heavy_clay_25_custom_obs.mdl file in the
<working directory>.
- Click OK to create the road graphics.
-
After road graphics creation, select the road graphics
in the Model Browser under the created Road Graphics systems
and define the Road Reference Marker in the Entity Editor.
-
The Track with Terrain Graphics is shown below.
- Save the model as Track_complete.
Simulation and Post-Processing
-
Under the Vehicle Tools menu, go to Run and open the
Analysis settings dialog.
-
Select the Run Offline check box and click the
Run button.
- After the simulation finishes, open a new HyperView window to visualize the results.
-
Click on the Open Model button, load the
Track_complete.h3d file in the panel, and click
Apply.
-
From the Animation toolbar, click the (Start/Pause Animation) button to animate the
model.
-
Click on the Contour option in the Ribbon to visualize
the soil plastic sinkage.
-
From the panel, select Plastic Sinkage as result type
and click Apply.
- Add a new HyperWorks session.
-
From the menu bar, select the HyperGraph
Line Chart application.
- Click on Open model and load the Track_complete.abf file from the MotionSolve run.
-
Under Y type select REQSUB, a list of soft soil results
is displayed. Select Track LH Link 0 and
RESULTS(2) to plot the sinkage of the left track link
0.