Brake Assist System (BAS) requirements have been established by
the Economic Commission for Europe (ECE) in R13H. Electronic
Stability Control (ESC) systems typically have the value added
function of Panic Brake Assist (PBA) which is defined as a Category
C (sensitive to multiple criteria) Brake Assist System. PBA is
designed to force the vehicle into Antilock Brake System (ABS) and
to maintain ABS control when the driver spikes the brake pedal and
then temporarily reduces brake pedal force before reasserting more
brake pedal force.
ECE test protocol requires the use of brake ramp applications to define the mean acceleration force (maF) curve which is used to
define the brake pedal force where ABS activates (FABS).
After completing the brake ramp application test maneuvers and
completing the data processing to define the maF curve,
FABS, upper, and
FABS,
lower, the
test driver then proceeds to run the panic brake assist portion of
the test. A high level of skill is required for a test driver to
spike the brake pedal and then reduce the brake pedal force to a
level between FABS,
upper and
FABS, lower.
Numerous panic brake assist test runs can cause the test driver
fatigue and the amount of force within specified range is difficult
to vary from the high end to the low end of acceptable range.
Hardware-in-the-loop simulation that includes the physical brake
system and the ability to control brake pedal force serves as
another test method which can be used to eliminate need for the
test driver and to more precisely control the amount of brake pedal
force varying from the high end to the low end of the specified
range.
The methodology of using hardware-in-the-loop (HIL) simulation
to validate Category C Brake Assist System vehicle performance will
be presented. HIL simulation provides additional ability to
validate different versions of ESC software and calibrations. The
combination of physical tests and simulations is an effective
methodology to demonstrate Category C Brake Assist System
compliance for all variants of a vehicle program.