Braking In a Turn

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
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. This section is used to allow the vehicle to reach steady state.
Turn direction Direction the vehicle turns during the event (as seen by the driver).
Velocity Initial vehicle velocity (meters/sec).
Look ahead time Time used by the Altair Driver to preview the road.
Prediction step size Maximum step size used by MotionSolve integrator.
Braking time The absolute time (in seconds) when the brakes are first applied.
Deceleration The deceleration rate of the vehicle in g’s.
Brake step duration The length of time the brakes are applied.
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).

Reference

ISO 7376-2006 - Passenger cars - Braking in A Turn - Open-loop test method.