Fishhook (roll stability) tests
NHTSA developed the fishhook test to ensure that vehicles sold in the USA would not roll over when subject to an avoidance manoeuvre.
The fishhook test has a steering input defined in terms of angle against time.
It is a steer + countersteer manoeuvre which might be applied by a panicked driver avoiding an obstacle in the road. Maximum severity is achieved by triggering the countersteer precisely when the maximum roll angle is reached following the initial steer input – this is accomplished automatically in AB Dynamics’ control software.
The fishhook test remains a requirement for all passenger vehicles sold in the USA.
High angular velocity and acceleration is required at the steering wheel, meaning that steer torque of 40-60Nm is generally required to follow the required profile.
AB Dynamics has a range of steering robots suitable for doing this, including the SR60, the SR60 Orbit and the Torus.
AB Dynamics’ path-following software can be used to guide the vehicle to precisely the desired location for the start of the fishhook test. This is particularly useful on tracks of restricted size, eliminating the stress of manually triggering the test.
Fishhook testing by its very nature is dangerous; it’s designed to provoke rollover. Using AB Dynamics’ Driverless Test System it can be done without a driver in the vehicle, eliminating the risk of injury.