Adding a Custom Vehicle

One of the attributes that make the TURN module so flexible is the ability to add custom vehicles to any vehicle library. We will be adding an IVECO Daily Midi Bus to illustrate the best method to accomplish this.

Selecting a vehicle type
 

Press the Add Vehicle button.

Enter a vehicle name and select a vehicle configuration that closely resembles the vehicle that has to be added. In this case it will be a “Single Unit bus”.

When selecting a vehicle Type the following must be considered:

• The number of units (trailers) the vehicle has.
• If it has more then one units then confirm whether the vehicle is articulated or not.
• Also confirm whether the trailers are semi-trailers (only a rear axle group) or full trailers (front steering axle and a rear axle group).
• An axle group can consist out of a maximum of 3 axles.

An empty Vehicle Dimension dialog will now be displayed. The picture on the dialog may differ quite a bit from what your new vehicle actually look like. We are only interested in the dimensions that you will be entering next.

Overall Vehicle Dimensions

The overall dimension of almost any vehicle can be obtained from the manufacturer in the form of a specification sheet. You can also physically measure the dimensions on the ground. If the vehicle or trailers have more than one rear axle, all measurements must be done to the centre of these axle groups.

Press the F1 key for assistance of what each dimension means.

Enter all the dimensions except the Steering angles.

Calculating the Steering Angle

The manufacturer will supply either the maximum track radius or the clearance circle radius. You must calculate the steering angle required to achieve the minimum radius.

The “Max.Steering Angle” is the maximum angle at which the steering wheels of a vehicle can be turned, measured from the longitudinal plane.

The maximum steering angle can either be measured, or calculated from the minimum turning radius, which is normally supplied with the specification sheet from the manufacturer.

Press the SETUP toolbar button to display the setup dialog.

Select the newly added vehicle and check the “Enforce Steering Angle” option.

If you are given the track radius then select “Swept Path” and if you are given the clearance radius then select “Swept path”.

Check the “Edit Vehicle Dimensions” button and enter an estimated “Max. Steering” angle.

Press OK.

Checking the steering angle against the vehicle turning radius
Now check the minimum turning circle for the calculated maximum steering angle by generating a minimum turning circle and comparing that to the manufacturer's specification. Press the MINIMUM ENVELOPE toolbar button.

This function will draw an envelope of the vehicles Track/Swept path running through a 180-degree turn at the maximum steering angle. Press OK. Specify a start point and a direction for initial movement.

You should now be able to see the following envelope:

Draw a circle with a radius of the Clearance / Track radius given by the manufacturer. In this case the track radius is 14.02 m. Move the circle over the envelope and see if the vehicle will be able to turn within the circle.

In this case it is clear that we have to increase the maximum steering angle.

Alter the steering angle and repeat the process until the envelope fits within the circle as follows:

The final values are: