Maximum yaw rate
Maximum yaw rate
(OP)
What's the maximum yaw rate a vehicle is likely to see during an extreme situation such as a spin or J-turn? (Something that a vehicle can recover from undamaged, not during a collision situation).
I know that the Bosch ESP yaw rate sensor (for example) tops out at 100deg/s, but is that just the upper bound for an 'elk' test or slalom situation, not the vehicle maximum?
Thanks, Ian
I know that the Bosch ESP yaw rate sensor (for example) tops out at 100deg/s, but is that just the upper bound for an 'elk' test or slalom situation, not the vehicle maximum?
Thanks, Ian





RE: Maximum yaw rate
Rod
RE: Maximum yaw rate
In a maneuver my rule of thumb is that the driver of a production car is unlikely to recover by steering from a yaw rate in excess of 40 deg/s, and even 20 deg/s is pretty aggressive at typical speeds (70-110 kph).
But that is a rule of thumb only. Might be easier to think in terms of latacc (m/s/s)=v(m/s).omega(rad/s)
Whoever calibrated the ESC on my car (Fiesta) seems to think less than 20 deg/s at 100 kph, working back from the steering wheel angle velocity. That means I have to drive very very smoothly on gravel roads if I don't want its 'help' (no Scandinavian flicks for you). I don't think it is calibrated for gravel roads, in a straight line at 100 kph cruise it goes off on some patches!
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Maximum yaw rate
At 80 kph that is 27 deg/s and 0.9 g.
That's modelled, using one of the canned models, obviously not correlated. I'm a bit surprised it hit 0.9g.
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: Maximum yaw rate
Would a high yaw rate 'incident' such as a handbrake turn, spin or J-turn form any part of a normal road vehicle test profile? I.e. is a maximum yaw rate likely to be specified for on-board equipment durability in the same way that vibration and acceleration tolerance is?
Thanks, Ian
RE: Maximum yaw rate
Anyway I guess I'm saying that 100 deg/sec seems a reasonable limit for the instrumentation, unless you are playing dodgems with Rod.
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.