Tutorial - Defining a new chassis model

The following process will demonstrate how to create a new chassis model using these interface definitions. This tutorial will guide you through building a chassis for a passenger car, i.e., a vehicle with 4 wheels.

  1. Create a new model that extends VehicleInterfaces.Chassis.Interfaces.FourWheelBase, it should look like this:

  2. In the component browser, right click on FourWheelBase and select Parameters from the context menu to produce the following parameter dialog

  3. This dialog allows you to enable/disable the optional connections by setting includeWheelBearings, includeSteeringWheel and includeChassisFrame as required for your new chassis model. The wheelHub connectors are of the type Modelica.Mechanics.MultiBody.Interfaces.FlangeWithBearing, the parameter includeWheelBearings controls whether the bearing connectors within the wheelHubs is enabled or not.
  4. You can now define your chassis model as required

Creating a simple chassis model for longitudinal motion

The following steps demonstrate how to create a simple chassis model for longitudinal motion. The chassis model will transmit the torque from the wheel hub connections in to a force being applied to the vehicle model. Only the longitudinal dynamics of the vehicle body will be modelled so no suspension is required.

Starting from step 3 above.

  1. First, decide which of the optional connectors are required in the model. For this example we don't need any of the optional connections

  2. Add the following blocks and connections to the diagram. When you draw the connections to the wheelHub connectors the dialog box shown below will appear asking which connector within the wheelHub connector you would like to make the connection to. As we are modelling the wheels as a 1D system you should select flange from the list of options which is the 1D connector within the wheelHub connector.

  3. Next, we need to check to see if any connections to the control signal bus are required for the chassis, see here for a complete list of the minimum connections required. In this case we need to add the vehicle longitudinal velocity to the control signal bus and this can be done by connecting a speed sensor to the vehicle body and then connecting this to the signal bus. As the longitudinal speed signals are added to the chassisBus we first need to add this connector. The chassisBus connector is VehicleInterfaces.Interfaces.ChassisBus. This should be connected to the controlBus, when this connection is made the following dialog is produced and should be completed as shown.

  4. When the connection between the sensor and the chassisBus connector is added the dialog below appears and should be completed as shown

  5. The model is now complete and should check successfully and can be used in any model compatible with the VehicleInterfaces library assuming the selected Driver model doesn't use the steering wheel or chassis frame connections

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