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
Steer input magnitude The magnitude of the steering input that is applied, in degrees. A positive value results in a left turn and a negative value turns the vehicle right.
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.
Velocity Velocity the vehicle maintains during the event in meters/sec.
End time Absolute end time of the event, in seconds.
Print interval Data is output to the plot files and graphics file at this time interval (seconds).

References

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