Altair Multi Body Solutions 2020.1 Release Notes

Highlights

The Altair Multi Body Solutions 2020.1 release provides several enhancements and bug fixes to the previous 2020 release. A consolidated list is shown below:
  • Scooter Suspensions Added to the Two-Wheeler MDL Library
  • Tire Contact Patch Force Graphics Option for AutoTires
  • Electric Power Assisted Steering in the Car/Light-Truck MDL Library
  • Rider Positioning Tool
  • MotionView Python API (Beta)
  • Graphics Performance
  • Cosimulation Improvements with EDEM
  • Support for Subroutine Written in Compose (OML)
  • PSTATE for Linear Analysis (MotionSolve only)
  • Other Enhancements
  • Resolved Issues

Scooter Suspensions added to the Two-Wheeler MDL Library

The Two-Wheeler MDL Library now includes scooter front and rear suspensions systems. The associated Assembly Wizard includes options to build a scooter model.


Figure 1.
The new suspension systems are:
  • Front Single Side Trailing Link Suspension
  • Front Double Side Trailing Link Suspension
  • Front Double Side Leading Link Suspension
  • Rear Trailing Link Mono Shock Suspension


Figure 2. Scooter Front Suspensions

Tire Contact Patch Force Graphics

The AutoTire now includes an option for tire contact patch force graphics, allowing you to visualize in HyperView the vertical, lateral, and longitudinal forces acting on the idealized tire contact patch. The forces are the integral of the friction and contact forces over the contact patch area between the road and tire. You control the color and scale of the graphics and their lateral offset from the contact patch location.
Note: The offset prevents the tire, wheel, and chassis graphics from obscuring the force graphics.


Figure 3.

Electric Power Assisted Steering (EPAS)

The car/light-truck MDL Library now includes an Electric Power Assisted Steering system. The steering assist is generated by an electric motor geared to the rack in parallel to the steering column. The assist torque is a function of the vehicle longitudinal speed and the wind-up in a torsion-bar in the steering column as a proxy for the driver’s steering effort.

The electric motor and torque boost curve are encapsulated in a model exchange FMU exported from Altair Activate. The corresponding Activate model (.scm file) is included with the FMU in Car/Light-Truck MDL Library, and may be viewed and modified with Activate.

Rider Entity and Positioning Tool

MotionAuto adds a new AutoRider entity representing the mass and inertia of a human. You can scale the height (mass) and density of rider and position the rider’s arms, legs, torso and head using sliders on the AutoRider panel. The range of joint motions are limited to realistic values for humans, but not all joint motions are adjustable. Since each body segment is an individual rigid body, when positioned the total mass remains unchanged, but the mass moments of inertia are updated.


Figure 4.

New Graphics for AutoRickshaw Example Model

MotionAuto adds new CAD based graphics for the AutoRickshaw Example model:


Figure 5.

MotionView Python API (Beta)

MotionView now has a Python interface (beta release) for creating a model. Using the API, MotionView models can be created, queried and modified through Python. This functionality opens avenues for modeling and customization, leveraging the power and flexibility of the Python language.

To use Python with MotionView, set the environment variable HW_MV_EXPERIMENTAL= PYTHON_CONTEXT_MENU_ENTRIES. The “Python Window” option is available on right-click context menu in the browser. The mview module is available within the Hyperworks package that can be imported in Python.


Figure 6.

The API documentation for each entity with examples is available in the MotionView Reference Guide.

Improved Graphic Performance

CAD Graphic representation and its memory usage has been improved. This results in better responsiveness to mouse manipulation such as Pan/Zoom/Rotate.

Cosimulation Improvements with EDEM

  • Mesh refinement ability while transferring geometry to EDEM is now available for CAD Graphics in the EDEM Subsystem panel.
  • A new "EDEM" menu is available. This menu offers all tools related to EDEM under one umbrella such as:
    • Creation of EDEM Subsystem
    • Running MS-EDEM co-simulation in batch mode
    • Generating H3D from EDEM results

Support for Subroutine Written in Compose (OML)

MotionSolve supports subroutines that are scripted in the OpenMatrix Language (OML) now using an embedded OML interpreter. The basic OML interpreter supports the basic OML syntax but does not include/support any of the additional toolboxes and libraries.

Furthermore, MotionSolve looks for a MATLAB installation to interpret *.m files. If the respective interpreter is not installed, MotionSolve will use its own basic OML interpreter to run *.m scripts instead.

The User Defined tab in MotionView for all entities that support User subroutines has been enhanced to provide Compose scripts as a subroutine.

OML-based subroutines are supported on Windows only. A Linux support for OML subroutines will be provided in future releases.

PSTATE for Linear Analysis (MotionSolve only)

You can define your own states via a new Reference_PlantState modeling element. Each Reference_PlantState contains a list of VARIABLES that have been defined in the model. These VARIABLES define the states to use in the linearization. MotionSolve uses these states for generating the linear problem. Reference_PlantState is currently supported in MotionSolve through .xml input files. MotionView will support this feature in a future release. For more information on Reference_PlantState, please see Reference: PlantState in the MotionSolve Reference Guide.

Other Enhancements

Descriptor State Space (MotionSolve only)
MotionSolve is able to generate matrices for state-space representation during a linear analysis step. The respective matrices (A, B, C, D) describe a mathematical model of a physical system as a set of input, output, and state variables related by first-order differential equations. Until now, MotionSolve only supported forces as inputs for state-space generation. In this release, you can define motion as inputs as well, which will result in a linear implicit model. The motions are added as algebraic constraints which leads to a descriptor state-space representation on the form of Eẋ = Ax + Bu and y = Cx + Du, where x is the state vector, u is the input vector, and y is the output vector. Descriptor State Space is currently supported in MotionSolve through .xml input files or the Msolve API; it is not available through MotionView. For more information on descriptor state space, please see Parameters: Linear Solver in the MotionSolve Reference Guide.
Data Summary Improvements
A new search option and filters are available in Data Summary. The View Options provides ability to:
  • Sorted based on dependency.
  • Filter for empty tabs and deactivated entities.
  • Filter points that are referred to as Body CG.
Forms
Forms panel can now display an image. If the cell in the form refers to a File name data member that has an image file, the image will be displayed within the cell.

Resolved Issues

MotionView
  • Messages on status bar were not being updated during Import, Export and opening of models.
  • Body data member of compliant joints were not updated after merging bodies.
  • Certain contact models failed to obtain mesh in the MotionSolve XML due to the mismatch of component names between MotionView and mesh generating Hypermesh.
  • An application error on browser scroll immediately after CAD import has been fixed.
  • Certain unit configuration with MNF to H3D conversion resulted in improper flex data to the solver.
  • An application error on creation of output for Contact entity has been resolved.
  • Transfer to EDEM of CADGraphics defined in reference to markers other than Global Frame resulted in an application error.
  • Template to recognize left or right-side members of a pair.
  • A change in dataset used by graphic resulted in undesired change in system topology.
MotionSolve
  • The Linux installer returned an error message regarding the lack of disc space for the root directory, even if you want to install the solver within another directory or drive.
  • In some cases, an inside cylinder got “shot away” within a cylinder-inside-cylinder contact if the penetration between the inside and outside cylinder was excessive.
  • Some Functional Mock-up Units based on Model Exchange were not solved correctly in MotionSolve.
  • After a Save and Load command, the internal states corresponding to the Motion Marker B1/B2/B3 were not initialized correctly, causing an offset between Motion states and the corresponding AX/AY/AZ values saved to the XML file. This caused some discontinuities in the results after the reload.
  • MotionSolve FMU generated by MotionView were not running in Activate on Linux.
  • MotionSolve Subroutine Builder failed to execute on the Linux platform.