Altair MotionView 2020 Release Notes

Highlights

The Altair MotionView 2020 release provides many new solutions and several enhancements. A consolidated list is shown below:
  • New Two-Wheeler Library and Three-Wheeler Solution
  • New Vehicle Tools Update Model Utility
  • New Drum Road for FIALA Tire
  • Altair Driver Improvements
  • Enhanced Road File Support
  • Improved Suspension Design Factors
  • MDL Vehicle Library Changes
  • Enhancements to MotionSolve - EDEM Interface
  • Other Enhancements
  • Known Issues
  • Resolved Issues

New Two-Wheeler and Three-Wheeler Solution

The 2020 release of MotionSolve provides a comprehensive solution for two-wheeled vehicles such as motorcycles, bicycles and scooters.


Figure 1.
The key features of the solution are:
  • Two-Wheeler library of parametric subsystems
  • Assembly Wizard to quickly assemble vehicles
  • Two-Wheeler and Leaning-Three-Wheeler Driver
  • Two-Wheeler Tire
  • Comprehensive event library
  • Three-Wheeler Example Models
Two-Wheeler library of parametric subsystems
The 2020 release of MotionSolve contains a new library for modeling two-wheeled vehicles like motorcycles, bicycles and scooters. The library includes:
  • Classic or inverted front fork with rigid or deformable strut rods
  • Mono-shock or twin shock rear fork
  • Rider mass and simple or complex graphics
  • Chain drive
  • CAD graphics for good model appearance
Assembly Wizard to quickly assemble vehicles
The Assembly Wizard builds full two-wheeler models containing the subsystems listed above. Half vehicle (suspension) models are not supported.
Two-Wheeler and Leaning-Three-Wheeler Driver
Altair Driver supports new steer and lean controllers for two-wheeled and leaning-three-wheeled vehicles.
  • For closed loop path following, the steer and lean controllers act in concert to steer and balance the two-wheeler as needed to follow the path.
  • For open loop events with two-wheeler and leaning-three-wheeler vehicles the lean angle is input as a function of time, the driver steers the front fork to achieve the lean angle while maintaining balance and the resulting vehicle path in the event output.
By default, vehicles with two wheels use the leaning driver configuration and events. Vehicles with three or more wheels use the non-leaning driver. If your three-wheeler vehicle is leaning, you can override the default non-leaning driver configuration from the driver panel shown below.


Figure 2.
Note: The driver does not interact with the vehicle through the rider, only through the steering.
Two-Wheeler Tire
Altair’s free FIALA Tire model has been extended to include camber-dependent lateral force and tire-road contact for rounded tire cross-sections. These changes make the FIALA model suitable for 2- or 3-wheelers. DELFT-TYRE, packaged with MotionSolve, also includes the MFMC-TYRE model for use with two-wheeler and leaning-three-wheeler vehicles.
Known Issue
At high camber angles seen in two-wheeler vehicles, the FIALA tire incorrectly adds energy to the vehicle for unknown reasons.
Comprehensive event library
All existing passenger car full vehicle events are supported for 2- and 3-wheeled vehicles also.
New Three-Wheeler Example Model
An Auto-Rickshaw example model is now available. It is built by combining a front fork system from the Two-Wheeler library with a quadra-link rear suspension system from the Car library. This model illustrates how systems from different libraries can be combined to create unique vehicles that can use Altair Driver with its set of events.
Note that Altair Driver is enhanced to:
  • Generalize and reduce the number of attachments to the vehicle
  • Detect the vehicle configuration based on the number of wheels and tires

With these enhancements Altair Driver adapts its feedforward path control to match the vehicle configuration, be it a two-wheeler, three-wheeler, car or multi-axle heavy truck.

New Vehicle Tools Update Model Utility

The HyperWorks 2020 release introduces an Update Model utility on the Vehicle Tools menu you can use update models to use 2020 MotionAuto System Definitions. A description of the updates is given in the table below. The update only functions for models created in HyperWorks v2107.3 or later.

When you open full vehicles models using Altair Driver, you will receive an alert asking you to update your model. For half vehicle models, no alert is given. If you choose not to update your model, it will work in the HyperWorks v2020 release. If you save your model to disk from HyperWorks v2020 without executing the Update Model function, you will not be prompted to update again.

If you do choose to update your model, a back-up of the model is saved to disk with “_backup” appended to the name, the model is updated (see the table below for the update actions) and the updated model is save to disk with “_updated" appended to the name.
Description Affected Entities Actions
Legacy tire systems replaced by AutoTire Any systems using the AutoCDTire, AutoCTITire, or AutoMFTire system definitions Single and pair systems using the AutoCDTire, AutoCTITire or AutoMFTIre system definitions are replaced with a single or pair system using the AutoTire system definition. Attachments and parameters like the tire and road property file are unchanged.
Dummy Steering Bodies removed Steering systems

Full and Half Vehicle Events (analyses)

 Dummy steering bodies and associated joints are deleted from steering systems (sys_steering), and from full and half vehicle events (analyses). Steering system joints are modified so the rack joins to the rack housing via a translational joint, the pinion to the rack housing via a revolute joint and the pinion to rack via a coupler.
Old Altair Driver System replaced by new system Altair Driver system The Altair Driver system is replaced with the new 2020 Altair Driver system. If needed the Altair Driver system definition is updated to use an *DefinitionInclude() pointing to the Altair Driver system definition in your HyperWorks 2020 installation folder.
Signal Generator System moves to Altair Driver Signal Generator (.sys_signal_generator) The user signals solver variables move to the Altair Driver System. You now create expressions for user signals from the Altair Driver system panel. The signal generator system is deleted from the model.
Known Issues
  • For models containing AutoCDTire systems that are updated to AutoTire, you need to reselect the tire property files before running a simulation.
  • For models created in HyperWorks versions older than v2017.3, update model will leave attachments for instrumentation systems unresolved.

New Drum Road for FIALA Tire

FIALA tire offers a new drum road where you specify the drum profile as drum height tabulated against drum circumference. You can enter the drum profile in the road property file directly or reference a .csv file to define the drum profile. Similarly, you can enter the drum surface velocity tabulated against time in the road property file or reference a .csv file to define the velocity verses time.

The center of the drum is automatically positioned under the wheel center, but you can also set the position of the drum relative to the road reference marker from the road property file. In addition, drum graphics are created for post processing. You set the width (length) of the drum cylinder and the number lines to draw on the cylinder surface in the road property file.

Altair Driver Improvements

Altair Driver is improved to make it easier to add the driver to vehicle models not built using the Assembly Wizard and MDL library systems. Specifically, Altair Driver:
  • May be added to your vehicle model from the browser context menu Add Auto Entity.
  • Needs 13 fewer attachments compared to the previous version.
  • Does not require a separate signal generator system. The signal generator system is now part of the Altair Driver system.
  • Identifies the direction the steering wheel or rack needs to move to make the vehicle turn left. This allows Altair Driver to steer the vehicle to follow a path independent of how the steering wheel or rack joint are constructed providing, of course, that the steering wheel and rack are connected to the steered wheels.
  • Identifies the number of wheels and tires in your vehicle to infer the vehicle type the best feedforward steering controller to use. However, you can override the vehicle type in the Altair Driver panel.
  • Includes fields on the Altair Driver panel to identify your vehicle’s forward and vertical directions in the global coordinate system. This allows Altair Driver to correctly orient paths relative to the vehicle.

Altair Driver requires that your model use AutoTires for modeling tires in your vehicle. However, the new update model feature will convert old tire systems to AutoTires to ease the transition.

Enhanced Road Support

The HyperWorks v2020 release extends support for OpenCRG, Point Cloud (3D Shell), and 3D Spline Road property files to all supported tire models (CDTire, DELFT-TYRE, FIALA, and FTIRE) to eliminate the need to convert road property files from one format to another based on the tire model used.

Example road property files are provided in the HyperWorks installation at …\hwdesktop\hw\mdl\autoentities\properties\Altair_Roads.

Improved Suspension Design Factors

Virtual Steer Axis Outputs
The suspension design factors (SDFs) virtual steer axis outputs are improved to give more accurate results. When calculating the virtual steer axis and values derived from the steer axis like virtual scrub radius and virtual caster trail, the suspension spring travel is locked by numerically manipulating the compliance matrix. Locking the spring travel eliminates any coupling between the suspension steering and ride motions yielding better results.
To facilitate the locking, the spring systems in MDLLIB suspensions now include a travel lock system. The travel lock system identifies the spring marker on the un-sprung body, the spring type: translational or rotation (for example, torsion bar) and primary direction of spring motion for use by the functions computing the virtual steer axis. Because the locking is done only on the compliance matrix input to the SDF computations, it has no effect on the suspension behavior or analysis results.
Roll Center Height
The roll center height calculation is updated to show negative values (roll center below the road surface). Previously, the absolute value of the roll center height was output giving incorrect results for some suspensions.

MDL Vehicle Library Changes

There are several changes to the MDL Vehicle Library in the v2020 release which are summarized below:
  • The Assembly Wizard option to build a Full Vehicle without Altair Driver is removed. But you can add the option by setting the environment variable: HW_MA_LEGACY_WIZARD=1.
  • Steering Dummy bodies and their associated joints in steering systems and analyses are removed.
  • Spring travel and steering locks are added to suspension systems and analyses to facilitate calculating suspension design factors like virtual steer axis.
  • The signal generator system moves to the Altair Driver system.
  • The Altair Driver system has fewer attachments to facilitate its use with two-wheeler and three-wheeler vehicles as well as cars and trucks.
Known Issue
The Wizard library selection (for example Car/Small Truck, Heavy Truck, Two-wheeler) is not saved to the .mdl file. Therefore, if you export wizard selections for a car model, select the Two-wheeler library, and then import car model wizard selections, the model created is a two-wheeler not a car. Reselecting the Car/Small Truck library and then importing the car model wizard selections will re-create the car model.

Enhancements to MotionSolve - EDEM Interface

In the v2019.1 release, MotionSolve added the capability to interface with the bulk material simulation software EDEM. This release presents further enhancements to this interface.
Linux Support
The EDEM co-simulation interface is now available on the Linux platform.
Cross Platform Support
The interface can be used across heterogeneous operating systems. MotionView/MotionSolve may be running on Windows and EDEM on Linux and vice-versa. The EDEM Subsystem panel is updated to transfer graphics to EDEM and create an EDEM system across heterogeneous platforms.


Figure 3.
H3D Generation Improvements
Generation of the EDEM particle .h3d file is now optional and occurs at the end of the simulation greatly reducing memory usage. Note that the EDEM system needs to be generated afresh to use this option. Previously, the .h3d file for the EDEM particles was always generated during simulation.
Coupling Start Time
The co-simulation interface is enhanced to allow the MotionSolve simulation to run for some time before starting the EDEM simulation. An additional field “Start EDEM simulation at time” is available in the EDEM subsystem panel. This feature is particularly useful for EDEM models whose start time is not 0.0 (for example, a pre-solved EDEM simulation until time T0).


Figure 4.
Batch Simulation
A batch script is now available to run the co-simulation in batch mode. The scripts msedemcosim.bat for Windows and msedemcosim.sh for Linux are located at ~install/hwdesktop/utility/mbd/edem.
Syntax to run the batch script:

msedemcosim.bat mvmodel.mdl edemmodel.dem

Where mvmodel.mdl and edemmodel.dem are the MotionView and EDEM models respectively.

Enhancements to Multi-Disciplinary Tools

The Multi-Disciplinary Tools (available through the Preference) offers the following new features.
Altair/Compose™ functions for use in conjunction with MotionView/MotionSolve
  • dsarun (Analysis features) - Submit multiple MotionSolve simulations with different values of a single parameter.
  • ms_dsafftplot / ms_dsafrfplot (Plotting - Compose) - Comparison plot of MotionView dsarun results in time and frequency domains, either as FFT of output signal or estimated FRF between output and input signal.
  • ms_frfplot (Plotting - Compose) - Compute and plot FRF between plant outputs / inputs from any MotionSolve linear analysis job.
A quick road builder tool road4durability (Experimental)
Build complex 3D CRG road profile with three lanes made of a series of obstacles to enable 2, 3 & 4 wheelers durability analysis. This feature is experimentation. To use the feature, set the environment variable HW_MD_EXPERIMENTAL=ALL.

Refer to the Multi-Disciplinary Tools help for additional details.

Other Enhancements

Functional Mockup Unit
  • The MotionView FMU entity now has an option to Check FMU for compliance using the fmu checker as per FMI standards. Check FMU provides information, warnings and/or errors about the FMU. MotionView’s Check Model feature runs the fmu checker in background and gives a warning if the checker returns any warnings or errors.
  • FMUs exported from MotionView now works on the Linux platform.
  • Some of the crash issues related to setting input variables and reading FMU have been fixed.
  • Incorrect FMU paths written to the solver deck in a different folder is fixed.
  • An ID assignment issue for solver variables in a model containing FMU is also fixed.
Linear Analysis
An option to write Compose/Activate state-space matrices during a Linear Analysis is now available under Run panel > Simulation Settings > Linear.
3D Contact
MotionSolve has a new option to compute contact forces based on mesh nodes other than at the element center. This option can be set in MotionView in the Contact panel – Advanced tab.


Figure 5.
FlexPrep
This utility now supports all unit choices offered by OptiStruct when generating flexbodies.
Solver Array - IC
The export of solver array of type IC has been updated to write the entries in integer or real form instead of scientific notation. This makes it easier when entries in the IC array are IDs of other solver elements.
Outputs
The output labels written to the solver deck on entities and entity sets have been enhanced to clearly identify the body and the connection entity the output belongs to. Note that this may require updates to existing report templates that depend on output labels.
Output Type Label as seen in result files Comments
Displacement

Velocity

Acceleration

 Two Points Body 1 from Body 2 (output_label) output_label is the label of the Output entity

connecting_entity is the force inducing entity that is associated with the body such as Joint, Bushing, SpringDamper etc.
Entity/Entity Sets - Bodies Body (output_label)
Entity/Entity Sets - other entities Entity on Body (output_label)

Force

 Entity/Entity Sets - Bodies connecting_entity on Body (output_label)
Entity/Entity Sets - other entities Entity on Body (output_label)
Allow Compliance Option for Joints
This option is turned ON by default when adding joints.
Export MDL Snapshot in the Run Panel
This option is now turned ON by default.
NLFE Belt Pulley System
The limitation of creating an NLFE Belt Pulley system with more than 300 elements is removed. MotionView warns you of potentially large solution times in this case.

Known Issues

  • Road Tools incorrectly positions the shoulder graphics for 3D Spline Roads.
  • Road Tools does not create centerline or shoulder graphics for Point Cloud Roads.
  • FMU exported from earlier version of MotionView will not readily work with HyperWorks v2020. A script fmu_patch.bat available at ~install/utility/mbd/fmu should be used to upgrade it.
  • There is a change in the folder structure of HyperWorks. Any custom scripts that uses the environment variable ALTAIR_HOME to locate the solver needs to be updated.

Resolved Issues

  • Roll Center Height: The roll center height calculation is updated to show negative values (roll center below the road surface). Previously, the absolute value of the roll center height was output giving incorrect results for some suspensions.
  • MacPherson Strut Camber Angle: Camber angle for MacPherson strut suspensions is now output correctly. Previously, a marker was not attached to the correct body.
  • Check Model took a long time for models having a large set of outputs.
  • Importing a MOTION of type ACCELERATION with a function expression from ADM resulted in an error.
  • CG Inertia Summary was erroneous in certain cases when Body coordinate systems were used along with Properties from Associated graphics.
  • Mass and inertia for Auto-Tires were not being reported in CG Inertia Summary.
  • The issue of including solver arrays within deactivated systems while exporting the model as FMU has been resolved.
  • Adding certain forms of FMU into the MotionView model resulted in a crash.
  • Expressions in the Input tab of the FMU was not possible without invoking the Expression Builder in certain cases.
  • FMU paths were not written relative to the exported MotionSolve xml.
  • Deactivating FMUs resulted in other solver variables losing their assigned IDs.
  • Graphics enclosed within another graphic whose display is set to wireframe/feature lines could not be selected or picked.
  • Models containing CADGraphics having an ampersand (&) in their name resulted in solver failure.
  • The help link to MotionSolve Functions from the Expression Builder was broken in version 2019.1.
  • CAD feature recognition is not exited during certain specific mouse movements away from the screen.
  • Mouse hover on points with left click press and the Point collector active in the CAD feature recognition ON results in a crash.
  • Switching to a HyperGraph window after editing curve values in MotionView resulted in an application error.
  • Creating File Graphics successively using FEM files resulted in distortion in graphic display.
  • Auto-MFTires referring to bodies that derived properties using associated graphics resulted in erroneous marker orientations in the solver deck.
  • Incorrect DOF calculations during Check Model (Tools > Options > Check Model > Degrees of Freedom) for entities under analysis, polybeams and compliant joints are fixed.