Vehicle Dynamics Library 3.7 is part of Modelon’s 2021.2 release.
Electrification Library Included
The clear trend with major global automotive and truck manufacturers is toward electric vehicles. Some manufacturers have already committed to be fully electric within this decade. Based on this trend, Modelon's Electrification Library (EL) is now available to all Vehicle Dynamics Library users beginning with this release.
The Electrification Library is intended for the design, analysis, and control of electrified systems including (but not limited to) ground vehicles, aircraft, and auxiliary power electric storage systems. The library provides scalable and flexible model architectures with compatible component models for electrified systems including batteries, machines, converters, loads, routing, and controls. Models include thermal interfaces and corresponding thermal models.
The combination of VDL for detailed chassis models and EL for detailed electrical component models allows users to analyze the overall system behavior of complete electric vehicles. Please see below for details of the new example models in VDL demonstrating this combination. Several new example experiments have also been added using these new models:
- The Acceleration experiment is a straight-line maneuver where the throttle aggressively applied. This experiment can be useful to determine motor sizing and torque-controller development.
- The Range Estimation experiment is a straight-line maneuver which demonstrates how a reduced fidelity chassis model can be used to estimate the range of a detailed electric powertrain when driven through a pre-defined drive cycle.
- The Torque Vectoring experiment is a j-turn maneuver that demonstrates how torque vectoring of the electric motors can be used to improve stability and handling.
New Electric Vehicle Examples
Two new electric vehicle examples have been added based on two new chassis and electric powertrains using components from the Electrification Library.
The Coupe has a chassis double wishbone front suspension and a trapezoidal rear suspension with a 2.6m wheelbase and 1.56m trackwidth. The Coupe vehicle examples use either the new DualMotorAWD or new SingleMotorRWD electric powertrains.
The Pickup chassis has a double wishbone front suspension and a five-link rear suspension with a 3.5m wheelbase and 1.8m trackwidth. The Pickup vehicle uses the new QuadMotorAWD electric powertrain.
New Electric Powertrain Examples
New electric powertrain templates and examples have been added using detailed battery and motor models from the Electrification Library. There are six examples available:
VDL models are now VI-Certified®
Vehicle models generated by VDL are now VI-Certified®. VI-Certified is an elevated partner program aimed at validating 3rd party software operation on VI-grade® simulators. VI-grade develops and optimizes its Driving Simulators with a complete software suite for vehicle modeling, graphics, sound & vibration, and motion cueing, thus enabling an off-the-shelf, turn-key solution. In addition, VI-grade’s open architecture and Application Programming Interface (API) make it easy to integrate 3rd party software and hardware components, as often desired by customers.
VI-grade decided to establish the VI-Certified program following the feedback received from clients, who requested the integration of partner technology to be consistently tested on their Driving Simulators. Customers need an efficient process to use partner software in their Driving Simulators, and do not want to be burdened with integration testing. Based on this feedback, VI-grade created VI-Certified, that enables customers to use their established products, knowing that these products have been fully tested by partners and assured by VI-grade. This reduces cost and time of deployment for their Driving Simulators.
Elimination of the scale and offset geometry parameters
The scale and offset parameters have been eliminated and will no longer change the positions of geometry positions. A survey of key VDL customers indicated that these parameters were not useful in their workflows. These parameters were actually problematic in that the geometry positions that were scaled and offset were stored in protected parameters. Accessing these protected parameters resulted in numerous warnings during checks or translation of the models. It was determined that the best approach to address these issues was to eliminate the parameters and allow users to reference geometry parameters directly. The downside is that users will have to scale and/or offset geometry parameters themselves.
Siemens Simcenter Tire Model Updated to 2021.1
The Siemens® Simcenter Tire model has been updated to version 2021.1. In MF-Tyre/MF-Swift 2021.1 the following improvements are included to increase the accuracy and robustness of the model:
- Increased model robustness for noise inputs (e.g. coming from sensor signals on HiL setups)
- Introduction of explicit modeling of the rubber relaxation properties at steer-hold situations
- Introduction of load dependency of the saturation of the tire aligning moment
- Introduction of inflation pressure dependency
Automatic transmission improvements
The gear shift behaviour for all automatic transmissions in VDL has been improved in the following ways:
- Updated upshift tables: acc_table_upshift tables for the Transmission examples have been parametrized using the traction diagram approach for the example powertrains. The TwelveSpeed transmission has been parametrized to work with the AutomaticRWD Truck driveline.
- Updated downshift and lockup tables: acc_table_downshift tables for the Transmission examples have been updated so that the downshift speeds are always lower than the upshift speeds. The acc_table_lockup tables have been updated so that the lockup speeds are in between the upshift and downshift speeds (This ensures the lockup clutch corresponding the correct gear is engaged). This has been achieved by using parametric downshift and lockup table functions. The downshift and lockup tables can be parametrized using tabular data as before if desired.
- The previous ChangeInterval block held the current gear if a shift command was received within t_min. The updated block performs the shift after t_min instead. The default t_min value has also been reduced to 0.2 sec instead of 0.99 sec.
- The DriveCycle driver can now take advantage of nearly 60 pre-defined, industry-standard drive cycles that have been added to the Modelon Base Library: DriveCycles. The example DriveCycle experiment has been updated to demonstrate this.
- The documentation for the polynomial suspension linkages Independent.PolynomialSTT, Independent.PolynomialTT, and AxleCarriages.PolynomialTT has been improved to describe the polynomial function and coefficients.
- A bug has been fixed in the WheelAngles sensor which provided incorrect windup angle output. Now this sensor provides the same outputs as the HubAngles sensor. As a result, TabularFromFile, Tabular1DfromFile and Tabular2DfromFile suspensions show improved correlation in the windup direction with a suspension used to generate the tabular data from a K&C analysis.
- The FormulaSAE chassis model has been updated to use the newer double wishbone pushrod/pullrod linkage topologies added in VDL 3.0. The front and rear linkages and antirollbar models ( FormulaMonoStrut, FormulaTwinStrutTT1, FormulaTwinStrutTT2) previously used, and specific to this chassis model, have been deprecated and will be removed in a future release. Further, a FormulaSAE vehicle has also been added.
Conversion of User Libraries
User libraries will automatically be converted from version 3.6. These conversions are made using the included conversion script: VehicleDynamics/Resources/Scripts/Convert_to_3.7.mos.