A Braking in a turn event simulates a vehicle decelerating in a circular path.
The purpose of this event is to measure the stability of a vehicle while braking and
turning. The vehicle is driven straight for the entry length and then turns onto the
circular path. At the "Time to Apply Brakes" time, the brake torque is ramped on using the
"Brake Step Duration" time so the vehicle slows at the "Desired Deceleration" rate. The
event ends at the "End of Simulation" time.
Standard outputs for the vehicle and tires are included in the event. The Altair Driver
maintains the proper speed, steers the vehicle, and decelerates at the proper time. Figure 1. Brake in Turn - Path Figure 2.
The parameters available in the Brake in Turn event are detailed in the following
table:
Parameter
Description
Units
Length unit selection (Model, m, ft).
Velocity unit selection (Model, m/s,
km/h, mph).
Acceleration unit selection (Model, m/s2,
g’s).
Radius
The radius of the circle that the vehicle CG will follow during the constant
radius portion of the event.
Initial straight
Length of the initial straight section.
Initial velocity
Initial vehicle velocity.
Final velocity
Final velocity desired in the simulation.
Turn direction
Direction the vehicle turns during the event (as seen by the driver).
Initial lateral acceleration
Estimated initial lateral acceleration, calculated using the initial speed
and the turn radius.
Final lateral acceleration
Estimated final lateral acceleration, calculated using the final speed and
the turn radius.
Deceleration
Desired deceleration of the vehicle after achieving steady state.
Turn direction
Direction the vehicle turns during the event (as seen by the driver).
Brake step duration
Step duration of the desired deceleration.
Look ahead time
Look ahead time, used by the Driver Feedforward steering model.
Prediction step size
Maximum step size, used by the Driver Feedforward steering model.
Print interval
Time interval of data output to the plot file (.plt) and
graphics file (.h3d).
Reference
ISO 7376-2006 - Passenger cars - Braking in A Turn - Open-loop test method.
