Pulse Steer

A Pulse steer event simulates a vehicle response to a sudden pulse input to the steering wheel while driving in a straight line at a constant speed.

The input to the event can be a steering wheel angle, and you can set the pulse magnitude and width. The pulse can be input as a sine, step, or ramp function and you control the width. The Altair Driver is used to maintain a constant speed, and standard outputs for the vehicle and tires are included in the Tire System and the Output Requests system. A plot template is available to plot the results.

The Pulse steer is used to characterize the dynamic response of the vehicle. The results are typically analyzed in the frequency domain to identify resonant frequencies of the vehicle. The vehicle is driven with a fixed steering wheel angle for approximately 10 seconds before and after the pulse event in order to provide sufficient data to the frequency analysis.


Figure 1.
The parameters available in the Pulse Steer event are detailed in the following table:
Parameter Description
Units Velocity unit selection (Model, m/s, km/h, mph).
Velocity Velocity the vehicle maintains during the event.
Steer input magnitude The magnitude of the steering input that is applied, in degrees.
Lean input magnitude* The magnitude of the demand lean input, in degrees.
Length of pulse The length of the steering pulse in seconds.
Function type The function type used in the pulse steer portion of the event (sin, step, or ramp).
Steer input time The absolute time in seconds when the steer pulse reaches its maximum angle.
Lean input time* The absolute time in seconds when the demand lean pulse reaches its maximum angle.
End time Absolute end time of the event, in seconds.
Print interval Time interval of data output to the plot file (.plt) and graphics file (.h3d).

*Applicable only for Two-wheeler events.

References

ISO +7401-2003 – Road Vehicles-Lateral transient response test methods-Open-loop test methods.