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.
