GRVA may wish to review amendments to UN Regulations No. 13, 13-H, 139 or 140, if available.
Documentation
GRVA-14-27
UN R140: Proposal for amendments (OICA)
UN R140: Proposal for amendments
Proposal for a provision to address use of a steering robot with mechanical power greater than 1200 W to enable testing of certain direct (low) steering gear ratio systems due to the given 0.7 Hz sine frequency.
Proposal for amendments to Annex 18 regarding special requirements for electronic control systems and for related transitional provisions for its entry into force.
GRVA-15-55
UN R140: Proposal to amend provisions for steering amplitude (OICA)
UN R140: Proposal to amend provisions for steering amplitude
Proposal to add the text, "In case that saturation of the front tyres happens before the above calculated magnitude angle, this angle may be used as the final steering amplitude, but only if this angle is greater or equal to 6.5 A.” based on the following justification:
Reaching fixed amplitude, i.e., fixed steering wheel angular speed due to given 0.7 Hz sine frequency, needs much more torque with quick steering gear ratio systems than with slow steering gear ratio systems, and produces much more wheel steer.
Car behavior (yaw rate, lateral acceleration and thus trajectory) is similar for all amplitudes above approx. 7 to 8 A (i.e., more than 7 times the steering wheel angle corresponding to 0.3 g), because front tires are saturated. More steer of the tires doesn’t provide more lateral force, so yaw rate and lateral acceleration don’t increase. Continuing to increase steering wheel amplitude after front tire saturation doesn’t give more information.
There might appear in the future some vehicles which have significantly low steering gear ratio (i.e., quick steering characteristics) and may need too much steering wheel torque to achieve the 270 degrees sine amplitude at 0.7 Hz (not reachable by conventional steering robots), then jeopardizing the easy approval of future beneficial steering equipment e.g. steering-by-wire systems.