VDL Version 4.2

VehicleDynamics Library 4.2 is part of Modelon���s 2023.1 release.

New Features

Support for the Michelin TameTire Model

VDL has been extended to include support of the Michelin TameTire�� 6.2.0 model.

TameTire is a physical tire model developed by Michelin R&D, especially for vehicle dynamic simulations. The model aims at an accurate description of the transient mechanical and thermal behavior of a tire.TameTire's main benefit compared to mathematical fit models is its capability to extrapolate tire forces and moments in a wide range of conditions including thermal effects, speed effects, tire inflation pressure and transient effects. TameTire can accurately predict the lateral force especially when the tire is at the limit of friction.

The TameTire wheel model is fully supported on all VDL built-in ground models.

Please see the TameTire Forces block for more information, requirements, and limitations.

Added Powertrain Transaxle Models

Transaxle models have been added in the Powertrains package. A transaxle is a transmission and a differential combined into one unit. Transaxles are nearly universal in configurations that have the engine placed at the same end of the car as the driven wheels. While it was possible to build a transaxle previously, including transaxle interfaces, templates and example models makes it easier for users requiring to model them. The transaxle package contains examples for Automatic, Manual, and ManualI (sequential) transmissions.

Three new transaxle powertrain templates have also been added:

  • FrontEngineTransaxle: Front engine/front wheel drive
  • MidEngineTransaxle: Mid engine/rear wheel drive
  • RearEngineTransaxle: Rear engine/rear wheel drive

New WheelBus Added to Wheels

A new WheelBus has been added to the base wheel interface. The WheelBus is intended to allow access to wheel information directly as opposed to either summary variables or the signalBus. The WheelBus is enabled by default, but can be disable by setting enable_wheel_bus to false.

The wheel sensor has been modified to always be enabled. Previously, the wheel sensor was conditionally enabled when the enable_signal_bus was true. The existing wheel sensors have been renamed from Ideal and IdealTwin to SingleSB and TwinSB, respectively. The suffix in the name indicates that these sensors put information on the signalBus. Two new sensors have been added SingleWB and TwinWB to put wheel information on the WheelBus and also optionally put the same information on the signalBus. The suffix in the name indicates that these sensors put information on the WheelBus. The default sensor in the wheel templates has been changed to use the new sensors: SingleWB and TwinWB.

New Truck Component Examples

A new Cross Steerable Axle linkage model has been added which uses a pitman-idler-draglink steering mechanism. A twin steerable axle model has also been added which uses this linkage.

Two stabilizer examples have been added (AxleFlex and AxleFlex2) which are modeled using FlexBeam components.


VI-Road Interface Improvement

Using vehicle models with the VI-Road ground model is now easier. Support for multi-point contact calculation models means that a VI-Road exclusive contact calculation block is no longer required. Further, it is now possible to use external tire models, such as DelftTyre, SwiftTyre and TameTire, on VI-Road surfaces.

Tire Dimensions for Third-Party Tire Models

The tire dimensions for all third-party tire models are now based on the dimensions specified in the tire property file. Tire dimensions such as unloaded radius, width, aspect ratio, and rim diameter are all updated automatically by reading the tire property file header information. This improvement applies to all third-party models: DelftTyre, FTire, SwiftTyre and TameTire.

Correction in Contact Patch Slip Velocities

The contact patch slip velocities calculations have been corrected to eliminate the contribution of the angular velocity about the spin axis. The changes were made in two contact calculation blocks: Single and ContactPointVelocities. If you reference either of these blocks, expect a very minor difference in the contact patch velocities and in simulation results.

Siemens Simcenter Tire Model Updated to 2212

The Siemens�� Simcenter Tire model has been updated to version 2212. In MF-Tyre/MF-Swift 2212, the following improvements are included to increase the accuracy and robustness of the model:

  • Internal solver timestep: An additional function has been added to set the timestep of the internal solver of MF-Tyre/MF-Swift (mfs_api_simulation_set_solver_frequency_t). This function would require an input (timestep for the swift library) from the end-user via the user interface. The default value is set to 1000Hz, if no input value is provided by the user.
  • Enveloping runtime performance: The run time when using the Enveloping use mode has been enhanced significantly and show an improvement of around 40%, especially on real-time platforms. There are no additional changes or settings required from the user for this.

Correction in Steering Systems Using Universal Joints

A bug has been fixed in Modelon.Mechanics.Rotational3D.Shaft that caused non-zero pinion angle initialization when using universal joints.

The steeringShaft component has been reversed in the Steering templates which means the joint phase angles (phi0_1 and phi0_23 parameters) are defined with respect to the steering wheel instead of the pinion as was the case previously. Documentation has been added describing the parameterization of the phase angles.

Steering systems using constant velocity joints are not affected by these changes.

Minor Improvements

  • AggregateMass has been added to the chassis and vehicle FlatPad experiment templates.
  • An example has been added showing the usage of categorized aggregate mass to calculate the sprung and unsprung mass of a chassis. Additionally, the motorsports chassis and suspensions examples have been updated to have categorized sprung and unsprung mass.
  • A bushing mounted stabilizer model has been added.

Minor Changes

  • The mounting frames of sensors have been renamed to mountFrame. This includes Ground, Chassis, Atmospheres, Brakes and ViDriveSim sensors.
  • The summary variables related to hub position have been renamed in all suspensions. The variables summary_rU_[xyz]_[12] and summary_rrelU_[xyz]_[12] have been renamed to summary_rH_[xyz]_[12] and summary_rrelH_[xyz]_[12], respectively.
  • The summary_lift variable in Bodies.Aerodynamics.Basic has be renamed to summary_drag which is the value it represents.
  • The SteerServo has been fixed to resolve an incorrect reaction torque applied to the chassis. This fix will cause a minor difference in simulation results.

Conversion of User Libraries

User libraries will automatically be converted from version 4.1. These conversions are made using the included conversion script: VehicleDynamics/Resources/Scripts/Convert_to_4.2.mos.